900 results on '"School of Mechanical Engineering Shanghai Jiao Tong University"'
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2. The nature of nano-sized precipitates in ferritic/martensitic steel P92 produced by thermomechanical treatment
- Author
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Liu, Huan [School of Mechanical Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240 (China)]
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- 2016
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3. Three axis electronic flight motion simulator real time control system design and implementation
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Wang, Xuyong [School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China)]
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- 2014
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4. Multiscale modeling and experimental validation for nanochannel depth control in atomic force microscopy-based nanofabrication
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Chen, Guozhen [State Key Laboratory of Mechanical System and Vibration, School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China)]
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- 2014
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- View/download PDF
5. Exploring pyrolysis and oxidation chemistry of o-xylene at various pressures with special concerns on PAH formation
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Long Zhao, Wenhao Yuan, Jiuzhong Yang, Philippe Dagaut, Yuyang Li, Fei Qi, Sandro Gail, School of Mechanical Engineering Shanghai Jiao Tong University, Shanghai Jiao Tong University [Shanghai], University of Science and Technology of China [Hefei] (USTC), Institut de Combustion, Aérothermique, Réactivité et Environnement (ICARE), Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut des Sciences de l'Ingénierie et des Systèmes (INSIS), and ANR-11-LABX-0006,CAPRYSSES,Cinétique chimique et Aérothermodynamique pour des Propulsions et des Systèmes Energétiques Propres(2011)
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flow reactor pyrolysis ,General Chemical Engineering ,General Physics and Astronomy ,Energy Engineering and Power Technology ,02 engineering and technology ,7. Clean energy ,01 natural sciences ,chemistry.chemical_compound ,020401 chemical engineering ,0103 physical sciences ,Organic chemistry ,PAH formation ,0204 chemical engineering ,Indene ,Benzene ,Chemical decomposition ,Naphthalene ,010304 chemical physics ,[SPI.FLUID]Engineering Sciences [physics]/Reactive fluid environment ,o-Xylene ,kinetic model ,General Chemistry ,Phenanthrene ,Toluene ,[CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry ,Fuel Technology ,chemistry ,13. Climate action ,o-xylene ,jet-stirred reactor oxidation ,Pyrolysis - Abstract
International audience; This work reports an experimental and kinetic modelling investigation on flow reactor pyrolysis and jet-stirred reactor oxidation of o-xylene. The flow reactor pyrolysis experiments were conducted over 1050-1600 K at 0.04 and 1.0 atm. Key products related to fuel decomposition such as o-xylyl radical, o-xylylene, benzocyclobutene and styrene, as well as polycyclic aromatic hydrocarbons (PAHs), were detected by using synchrotron vacuum ultraviolet photoionization mass spectrometry. The jet-stirred reactor oxidation experiments were performed at 10 atm, 800-1200 K, a residence time of 0.5 s and equivalence ratios of 0.5, 1.0 and 2.0. Speciation were conducted by using gas chromatography and Fourier transform infrared spectrometry. A kinetic model of o-xylene was developed from our previous models of aromatic fuels and validated against both present data and experimental data in literature. Styrene is observed as the dominant product in the pyrolysis of oxylene and it is mainly produced from the isomerization of o-xylylene directly or via benzocyclobutene as an intermediate species. C9 PAHs (indenyl, indene and indane), phenanthrene and its methyl derivatives were observed as the abundantly produced bicyclic and tricyclic PAHs. The main formation pathways of bicyclic and tricyclic PAHs are found to be different at low and atmospheric pressures, depending on the major precursors produced. Particularly, the self-combination reactions of o-xylyl and the addition reaction of o-xylyl with benzyl and subsequent stepwise H-loss/cyclization reactions are found to be the main sources of methylphenanthrene and dimethylphenanthrene. In the JSR oxidation of o-xylene, toluene and benzene were observed as the abundantly produced aromatic products, while o-methylbenzaldehyde was among the most abundantly produced oxygenated aromatics. Modelling analysis reveals that o-xylyl radical is also the dominant fuel consumption product. Its consumption mainly proceeds through the oxidation by HO2 and finally produces omethylbenzaldehyde. Further decomposition reactions of o-methylbenzaldehyde contribute to the formation of other major oxygenated aromatics such as cresol and benzofuran. Indene and naphthalene were also observed in the oxidation of o-xylene, which are mainly produced from the stepwise Hloss/cyclization reaction sequence of o-methylethylbenzene and decomposition of dibenzofuran, respectively.
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- 2021
6. Design, analysis and testing of a parallel-kinematic high-bandwidth XY nanopositioning stage
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Zhu, Li-Min [State Key Laboratory of Mechanical System and Vibration, School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China)]
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- 2013
- Full Text
- View/download PDF
7. Low-temperature chemistry triggered by probe cooling in a low-pressure premixed flame
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Fei Qi, Hanfeng Jin, Jiuzhong Yang, Meirong Zeng, Xiaoyuan Zhang, Wei Li, Philippe Dagaut, Tianyu Li, Yan Zhang, Jiabiao Zou, Yuyang Li, Wenhao Yuan, Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration (CISSE), Shanghai Jiaotong University, Institut de Combustion, Aérothermique, Réactivité et Environnement (ICARE), Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut des Sciences de l'Ingénierie et des Systèmes (INSIS), Shanghai Jiao Tong University [Shanghai], and School of Mechanical Engineering Shanghai Jiao Tong University
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Kinetic modeling ,General Chemical Engineering ,Analytical chemistry ,General Physics and Astronomy ,Energy Engineering and Power Technology ,chemistry.chemical_element ,02 engineering and technology ,Photoionization ,photo ionisation ,Mole fraction ,01 natural sciences ,7. Clean energy ,Oxygen ,Propene ,chemistry.chemical_compound ,020401 chemical engineering ,Orders of magnitude (specific energy) ,synchrotron ,0103 physical sciences ,0204 chemical engineering ,Premixed flame ,Argon ,010304 chemical physics ,[SPI.FLUID]Engineering Sciences [physics]/Reactive fluid environment ,General Chemistry ,Hydroperoxides ,[CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry ,Fuel Technology ,chemistry ,13. Climate action ,Flame chemical structure ,Stoichiometry - Abstract
International audience; Previous studies on sampling probe effects in the premixed flat flame showed that the temperature in the preheat zone can be lowered down to low-temperature oxidation regime (e.g., 400–800 K). In order to investigate the contribution of the low-temperature chemistry in flame-sampling experiments, a stoichiometric laminar premixed flat flame of ethylene/oxygen/argon was investigated at 30 Torr using synchrotron vacuum ultraviolet photoionization mass spectrometry (SVUV-PIMS) in this work. Ethyl hydroperoxide (C2H5OOH) was identified and quantified in the present experiment, providing an experimental evidence for the existence of low-temperature chemistry in flame-sampling experiments. In addition to C2H5OOH, the formation of several other intermediates like ethanol and formaldehyde was also influenced by the low-temperature chemistry in the present flame-sampling experiment. A literature kinetic model (Hashemi et al., 2017) was used for predictions and analyses. The difference between the predicted maximum mole fractions of C2H5OOH with the perturbed and unperturbed temperature profiles can reach up to five orders of magnitude. The great improvement of the predictions with the perturbed temperature profiles indicates that the observed low-temperature chemistry in the present flame sampling experiment originates from the probe-induced perturbations, which lowers down the temperature window of the preheat zone and leads to a temperature drop of more than 400 K compared with the unperturbed temperature profile. Through modeling analysis, the low-temperature oxidation chemistry of ethylene involved in the present flame-sampling experiment was discussed. The influence of low-temperature chemistry in the present experiment has also been demonstrated by comparing the model predictions with/without key reactions at low temperatures. It is concluded that predicted maximum mole fractions of several low-temperature chemistry related intermediates, i.e. C2H5OOH, ethanol and formaldehyde, are strongly reduced without these reactions, while low-temperature chemistry only has negligible influence on the predictions of the fuel and the majority of flame intermediates. Furthermore, preliminary experiments were also conducted in ethane, propene and n-butane flames under similar conditions, where hydroperoxides can also be observed.
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- 2019
8. Experimental assessment of the sudden-reversal of the oxygen dilution effect on soot production in coflow ethylene flames II: soot radiation and flame transition analysis
- Author
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Weiwei Cai, Guillaume Legros, Jean-Louis Consalvi, Céline Morin, Fengshan Liu, Qianlong Wang, Haifeng Liu, State Key Laboratory of Engines, Tianjin University, Tianjin, Institut universitaire des systèmes thermiques industriels (IUSTI), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Automatique, de Mécanique et d'Informatique industrielles et Humaines - UMR 8201 (LAMIH), Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF)-INSA Institut National des Sciences Appliquées Hauts-de-France (INSA Hauts-De-France), Sorbonne Université (SU), Measurement Science and Standards, National Research Council of Canada, Ottawa, Ontario, Canada, Key Lab of Education Ministry for Power Machinery and Engineering, School of Mechanical Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China, State Key Laboratory of Engines, Tianjin University, Tianjin, 300072, China, and Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)
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Materials science ,010504 meteorology & atmospheric sciences ,Analytical chemistry ,chemistry.chemical_element ,medicine.disease_cause ,01 natural sciences ,Oxygen ,complex mixtures ,soot ,[SPI]Engineering Sciences [physics] ,fluids and secretions ,Radiative transfer ,medicine ,Spectroscopy ,0105 earth and related environmental sciences ,ethylene diffusion flames ,Radiation ,Diffusion flame ,Laminar flow ,[SPI.MECA]Engineering Sciences [physics]/Mechanics [physics.med-ph] ,flame transition ,smoking flames ,Atomic and Molecular Physics, and Optics ,Soot ,humanities ,Dilution ,local radiative intensity field ,chemistry ,13. Climate action ,Volume fraction ,Intensity (heat transfer) - Abstract
The current study focuses on the radiative characteristics of heavy smoking flames that are formatted by oxygen being added to the fuel stream of a steady laminar ethylene diffusion flame. In such a scenario, based on the experimental local soot temperature and volume fraction results, the soot local radiative fields are obtained by solving the Radiative Transfer Equation (RTE). Along with the diluted range (oxygen volume fraction X O 2 a x from 0 to 32%), the flame undergoes two significant transitions, i.e., smoking and non-smoking; however, only one remarkable radiative intensity transition between 30% and 32% is identified. The radiative loss due to the oxygen chemical effect is further assessed by comparing with that of N2 diluted flames. It is found that the chemical effect on radiative loss promotion is undermined by approximately 25%, compared with that on soot formation promotion. In contrast, the oxygen dilution effect results in a similar reduction level on soot formation propensity and soot radiative loss. Furthermore, the correlations between relative soot consumption rate and cumulated radiative loss below the flame tip region are explored, and the results indicate that the initial relative oxidation rate at the position of z F v , max (the peak location of flame cross-section mean soot volume fraction) and its residence time are two important factors that may affect the final flame smoking/non-smoking transition. Eventually, these local soot radiative intensity fields, together with the local soot temperature and volume fraction fields, provide a more comprehensive benchmark to refine the soot oxidation model as the ISF workshop required and understand the flame transition mechanism in the sooting flames.
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- 2020
9. An integrated reliability approach with improved importance sampling for low-cycle fatigue damage prediction of turbine disks
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Guang-Chen Bai, Hai-Feng Gao, Enrico Zio, Anjenq Wang, School of Mechanical Engineering Shanghai Jiao Tong University, Shanghai Jiao Tong University [Shanghai], Centre de recherche sur les Risques et les Crises (CRC), MINES ParisTech - École nationale supérieure des mines de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Politecnico di Milano [Milan] (POLIMI), Kyung Hee University (KHU), and Beijing University of Aeronautics and Astronautics (BUAA)
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Low-cycle fatigue damage ,021110 strategic, defence & security studies ,Computer science ,Random variable ,020209 energy ,Computation ,0211 other engineering and technologies ,Probabilistic logic ,02 engineering and technology ,Turbine disk ,Improved importance sampling ,Turbine ,Industrial and Manufacturing Engineering ,Reliability engineering ,Surrogate model ,0202 electrical engineering, electronic engineering, information engineering ,Moving least squares ,Reliability approach ,[SHS.GEST-RISQ]Humanities and Social Sciences/domain_shs.gest-risq ,Safety, Risk, Reliability and Quality ,Importance sampling ,Reliability (statistics) ,ComputingMilieux_MISCELLANEOUS - Abstract
The objective of this paper is to develop an effective reliability approach to improve the numerical accuracy and computational efficiency of the low-cycle fatigue (LCF) damage prediction for turbine disks. The approach is called as distributed collaborative (DC) probabilistic substructure (PS)-based moving improved importance-sampling least-squares (MIIL), DC-PS-MIIL. In this approach, the MIIL model is firstly developed by combining an improved importance sampling (IIS) with moving least squares (MLS), to reduce the computation burden and improve the precision of surrogate model; then, the PS-MIIL comes up by integrating probabilistic substructure (PS) method into MIIL, to address the interface forces of turbine disks; finally, DC-PS-MIIL is proposed by incorporating distributed collaborative strategy with PS-MIIL. The comprehensive analysis procedure with DC-PS-MIIL is shown to simplify the probabilistic assessment of complex structures for improving numerical accuracy and simulation efficiency. Taking the LCF damage prediction of turbine disks as an example, DC-PS-MIIL is demonstrated to be an effective reliability approach. Also, numerical results show that the confidence levels, applied cycles and coefficients of variation (CVs) of random input variables have important impact on the LCF damage reliability for turbine disks.
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- 2020
10. A comprehensive experimental and kinetic modeling study of n-propylbenzene combustion
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Fei Qi, Philippe Dagaut, Yuyang Li, Wenhao Yuan, Zhandong Wang, Yizun Wang, School of Mechanical Engineering Shanghai Jiao Tong University, Shanghai Jiao Tong University [Shanghai], Institut de Combustion, Aérothermique, Réactivité et Environnement (ICARE), Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut des Sciences de l'Ingénierie et des Systèmes (INSIS), National Synchrotron Radiation Laboratory (NSRL), and University of Science and Technology of China [Hefei] (USTC)
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Jet-stirred reactor ,Kinetic modeling ,020209 energy ,General Chemical Engineering ,Analytical chemistry ,General Physics and Astronomy ,Energy Engineering and Power Technology ,02 engineering and technology ,Combustion ,7. Clean energy ,Ethylbenzene ,Propylbenzene ,chemistry.chemical_compound ,020401 chemical engineering ,0202 electrical engineering, electronic engineering, information engineering ,0204 chemical engineering ,Indene ,propylbenzene ,Shock tube ,ComputingMilieux_MISCELLANEOUS ,Naphthalene ,Atmospheric pressure ,[SPI.FLUID]Engineering Sciences [physics]/Reactive fluid environment ,Oxidation -mechanism ,General Chemistry ,[CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry ,Fuel Technology ,chemistry ,13. Climate action ,Pyrolysis ,combustion - Abstract
This work presents a comprehensive experimental and kinetic modeling study on the combustion of n -propylbenzene. Flow reactor pyrolysis of n -propylbenzene at 0.04, 0.2 and 1 atm and laminar premixed flames of n -propylbenzene at 0.04 atm with equivalence ratios of 0.75 and 1.00 were investigated with synchrotron vacuum ultraviolet photoionization mass spectrometry. Jet stirred reactor (JSR) oxidation of n -propylbenzene at 10 atm with equivalence ratios of 0.5, 1.0, 1.5 and 2.0 was investigated with gas chromatography. A detailed kinetic model for n -propylbenzene combustion with 340 species and 2069 reactions was developed and validated against the data measured in this work. Model analyses such as rate of production analysis and sensitivity analysis were also performed to reveal the key pathways in the consumption of fuel and formation of polycyclic aromatic hydrocarbons (PAHs). The analysis results demonstrate that the benzylic C C bond dissociation reaction is crucial for the decomposition of n -propylbenzene in the pyrolysis and rich flame. Low temperature oxidation reactions play important roles in the high pressure JSR oxidation of n -propylbenzene. In addition, the formation pathways of PAHs are strongly related to the fuel structure, especially for the formation of bicyclic PAHs such as indene and naphthalene. Furthermore, the present model was also validated against previous experimental data of n -propylbenzene combustion under a wide range of conditions, including ignition delay times, laminar flame speeds, extinction strain rates, speciation profiles in atmospheric pressure JSR oxidation, flow reactor oxidation and high pressure shock tube pyrolysis and oxidation.
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- 2017
11. Hydrodynamic instability and sound amplification over a perforated plate backed by a cavity
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Xiwen Dai, Yves Aurégan, School of Mechanical Engineering Shanghai Jiao Tong University, Shanghai Jiao Tong University [Shanghai], Laboratoire d'Acoustique de l'Université du Mans (LAUM), and Le Mans Université (UM)-Centre National de la Recherche Scientifique (CNRS)
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geography ,geography.geographical_feature_category ,Materials science ,Physics::Instrumentation and Detectors ,Acoustics ,Physics::Optics ,01 natural sciences ,Instability ,010305 fluids & plasmas ,[PHYS.MECA.ACOU]Physics [physics]/Mechanics [physics]/Acoustics [physics.class-ph] ,Physics::Fluid Dynamics ,0103 physical sciences ,sense organs ,010301 acoustics ,Sound (geography) - Abstract
International audience; The long-wavelength hydrodynamic behaviour over a cavity-backed perforated plate, in a duct with a mean shear flow, is studied numerically using the multimodal method, where the acoustic and hydrodynamic disturbances are calculated from the linearized Euler equations. The flow-acoustic coupling near the perforated plate is first solved hole by hole, and results indicate a well-defined large-scale hydrodynamic wave over the plate, with a wavelength close to the plate length at the peak sound amplification frequency when a plane acoustic wave is introduced from the upstream duct. Since the hydrodynamic wavelength is one order larger than the period of the perforation, the effect of the perforated plate is then described by a homogeneous plate impedance. It is shown that the homogenized approach approximately represents the discrete approach in this problem.
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- 2019
12. New insights into propanal oxidation at low temperatures: An experimental and kinetic modeling study
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Xiaoyuan Zhang, Chuangchuang Cao, Jiabiao Zou, Philippe Dagaut, Tianyu Li, Wei Li, Jiuzhong Yang, Yan Zhang, Yuyang Li, Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration (CISSE), Shanghai Jiao Tong University [Shanghai], Institut de Combustion, Aérothermique, Réactivité et Environnement (ICARE), Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut des Sciences de l'Ingénierie et des Systèmes (INSIS), School of Mechanical Engineering Shanghai Jiao Tong University, National Synchrotron Radiation Laboratory, and University of Science and Technology of China [Hefei] (USTC)
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General Chemical Engineering ,Kinetics ,Photoionization ,010402 general chemistry ,Mass spectrometry ,Kinetic energy ,Photochemistry ,7. Clean energy ,01 natural sciences ,Redox ,0103 physical sciences ,Physical and Theoretical Chemistry ,ComputingMilieux_MISCELLANEOUS ,Addition reaction ,010304 chemical physics ,Atmospheric pressure ,Chemistry ,Mechanical Engineering ,[SPI.FLUID]Engineering Sciences [physics]/Reactive fluid environment ,Atmospheric temperature range ,kinetic modeling ,0104 chemical sciences ,Jet-Stirred reactor ,13. Climate action ,propanal ,Oxidation mechanism - Abstract
The kinetics of propanal oxidation was studied in a jet-stirred reactor (JSR) at atmospheric pressure. The investigated temperature range is from 450 to 800 K at two different equivalence ratios (0.35 and 4.0). Thanks to the synchrotron vacuum ultraviolet photoionization mass spectrometry (SVUV-PIMS), critical intermediates were identified, including methylperoxy, methyl hydroperoxide, ethylperoxy, ethyl hydroperoxide, α-lactone, β-propiolactone and ketohydroperoxides. A kinetic model for propanal oxidation was also developed and validated against the present experimental results, as well as those available from the literature. Main chain-branching pathways under the investigated conditions were analyzed based on present experimental data and kinetic model. The O2 addition reaction to the propanoyl radical and subsequent oxidation reactions play an important role in determining the oxidation rate of propanal under fuel-lean conditions, especially in the low-temperature oxidation region. Under fuel-rich conditions, the decomposition of the propanoyl radical is predominant and C2H5 relevant reactions consequently determine the kinetics of oxidation of propanal.
- Published
- 2019
13. The effects of nanosized particles on microstructural evolution of an in-situ TiB2/6063Al composite produced by friction stir processing
- Author
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Mingliang Wang, Jian Li, Gang Ji, Huang Wang, Yurong Wu, András Borbély, Zhe Chen, Shengyi Zhong, Shanghai Jiao Tong University [Shanghai], Inst Nucl Phys & Chem, Laboratoire Georges Friedel (LGF-ENSMSE), École des Mines de Saint-Étienne (Mines Saint-Étienne MSE), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Centre National de la Recherche Scientifique (CNRS), Centre Science des Matériaux et des Structures (SMS-ENSMSE), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), PMM-ENSMSE- Département Physique et Mécanique des Matériaux, Unité Matériaux et Transformations - UMR 8207 (UMET), Centre National de la Recherche Scientifique (CNRS)-Université de Lille-Ecole Nationale Supérieure de Chimie de Lille (ENSCL)-Institut National de la Recherche Agronomique (INRA), School of Mechanical Engineering Shanghai Jiao Tong University, Institut National de la Recherche Agronomique (INRA)-Ecole Nationale Supérieure de Chimie de Lille (ENSCL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Southwest Institute of Nuclear Physics and Chemistry [Mianyang], China Academy of Engineering Physics (CAEP), Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-École des Mines de Saint-Étienne (Mines Saint-Étienne MSE), Institut National de la Recherche Agronomique (INRA)-Ecole Nationale Supérieure de Chimie de Lille (ENSCL)-Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), and Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)
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Friction stir processing ,Materials science ,Composite number ,SEVERE PLASTIC-DEFORMATION ,DISLOCATION DENSITY ,GRAIN-REFINEMENT ,Metal-matrix composites (MMCs) ,HIGH-PRESSURE TORSION ,X-ray diffraction (XRD) ,Neutron diffraction ,[SPI.MAT]Engineering Sciences [physics]/Materials ,STRENGTH ,lcsh:TA401-492 ,General Materials Science ,Transmission electron microscopy (TEM) ,ComputingMilieux_MISCELLANEOUS ,ALUMINUM-ALLOYS ,WELDED-JOINTS ,Mechanical Engineering ,Metallurgy ,Recrystallization (metallurgy) ,PROFILE ANALYSIS ,[CHIM.MATE]Chemical Sciences/Material chemistry ,MECHANICAL-PROPERTIES ,Grain size ,Grain growth ,Mechanics of Materials ,Particle-size distribution ,[PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci] ,lcsh:Materials of engineering and construction. Mechanics of materials ,Severe plastic deformation ,Electron backscatter diffraction ,TIB2 PARTICLES - Abstract
The homogenous redistribution of nanosized TiB2 particles in a fine-grained in-situ AA6063/TiB2 composite has been achieved by friction stir processing (FSP). The effects of TiB2 particles on as-deformed structure in the nugget zone and its thermal stability after additional T6 heat treatment are quantitatively evaluated by using neutron diffraction, scanning electron microscopy associated with electron backscatter diffraction and synchrotron X-ray line profile analysis. The results are compared to those obtained from a FSPed AA6063 alloy and, show first that, average grain size of the FSPed AA6063/TiB2 composite is smaller than that of the FSPed AA6063 alloy, while grain size distribution is more uniform. Second, dislocation density estimated in the FSPed AA6063/TiB2 composite is higher than that in the FSPed AA6063 alloy. Third, a small number of grains are dynamically recrystallized in the FSPed AA6063/TiB2 composite compared to its alloy counterpart, which indicates that recrystallization and grain growth during FSP and T6 heat treatment are effectively inhibited by the presence of nanosized TiB2 particles. Keywords: Metal-matrix composites (MMCs), X-ray diffraction (XRD), Transmission electron microscopy (TEM), Neutron diffraction, Friction stir processing
- Published
- 2015
14. A cavity-by-cavity description of the aeroacoustic instability over a liner with a grazing flow
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Xiwen Dai, Yves Aurégan, School of Mechanical Engineering Shanghai Jiao Tong University, Shanghai Jiao Tong University [Shanghai], Laboratoire d'Acoustique de l'Université du Mans (LAUM), and Le Mans Université (UM)-Centre National de la Recherche Scientifique (CNRS)
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Physics ,Mechanical Engineering ,Instability ,Shear layers ,Mechanics ,Condensed Matter Physics ,01 natural sciences ,010305 fluids & plasmas ,Euler equations ,[PHYS.MECA.ACOU]Physics [physics]/Mechanics [physics]/Acoustics [physics.class-ph] ,Physics::Fluid Dynamics ,Transverse plane ,symbols.namesake ,Convective instability ,Mechanics of Materials ,0103 physical sciences ,Aeroacoustics ,symbols ,Duct (flow) ,Shear flow ,010301 acoustics ,Bloch wave - Abstract
International audience; This paper presents a two-dimensional (2D) cavity-by-cavity description of a convective instability near a lined wall with low dissipation due to the coupling of hydrodynamic modes with resonance of the wall. For a liner consisting of an array of deep cavities periodically placed along a duct containing a mean shear flow, the acoustic and hydrodynamic disturbances are described by the linearized Euler equations. The Bloch modes and the scattering matrix of periodic cells are used to examine the instability over the liner. The unstable Bloch mode is due to the coupling of a hydrodynamic mode in the shear flow with the cavity resonance. It is demonstrated that even when all the transverse modes are stable in the duct-cavity system, i.e. when the Kelvin-Helmholtz instability of the shear flow over the cavities does not occur, such an instability over the liner can still exist. The unstable Bloch wave, excited by the incident sound wave at the upstream part of the liner, convectively grows along the liner, and regenerates sound near the downstream edge of the liner with a sound level higher than that incident sound level. It is shown that a homogenized approach, where the wall effect is described by a homogeneous impedance, can also explain the unstable behaviour above the liner. It reveals that a small wall resistance and a small and positive reactance are two necessary conditions for such an instability.
- Published
- 2018
15. Low-temperature gas-phase oxidation of diethyl ether: Fuel reactivity and fuel-specific products
- Author
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Yuyang Li, Frédérique Battin-Leclerc, Eike Bräuer, Luc-Sy Tran, Fei Qi, Meirong Zeng, Katharina Kohse-Höinghaus, Julia Wullenkord, Olivier Herbinet, Laboratoire Réactions et Génie des Procédés (LRGP), Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Physicochimie des Processus de Combustion et de l’Atmosphère - UMR 8522 (PC2A), Université de Lille-Centre National de la Recherche Scientifique (CNRS), Universität Bielefeld, School of Mechanical Engineering Shanghai Jiao Tong University, Shanghai Jiao Tong University [Shanghai], Université de Lille, CNRS, Physicochimie des Processus de Combustion et de l’Atmosphère - UMR 8522 [PC2A], Laboratoire Réactions et Génie des Procédés [LRGP], and Centre National de la Recherche Scientifique (CNRS)-Université de Lorraine (UL)
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Diethyl ether ,020209 energy ,General Chemical Engineering ,Analytical chemistry ,02 engineering and technology ,Photoionization ,Mass spectrometry ,7. Clean energy ,01 natural sciences ,010305 fluids & plasmas ,chemistry.chemical_compound ,Acetic acid ,Biofuel ,0103 physical sciences ,0202 electrical engineering, electronic engineering, information engineering ,Reactivity (chemistry) ,[SPI.GPROC]Engineering Sciences [physics]/Chemical and Process Engineering ,Physical and Theoretical Chemistry ,Plug flow reactor model ,Dual NTC zone phenomenon ,Electron ionization ,Mechanical Engineering ,[CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry ,chemistry ,13. Climate action ,Gas chromatography ,Low-temperature oxidation ,Detailed kinetic model - Abstract
International audience; Diethyl ether (DEE) has been recently suggested as a potential biofuel for compression-ignition engines that are known to be significantly controlled by low-temperature (LT) chemistry. However, the LT oxidation of DEE has not fully been understood in term of the formation of LT fuel-specific products. We have thus studied the oxidation of DEE by examining detailed profiles of its oxidation products under LT conditions (400-1100 K). To this end, we have used a dedicated experimental setup including a nearly-atmospheric jet-stirred reactor (JSR) coupled to online gas chromatography (GC). The experiments were complemented by measurements made with a JSR coupled to tunable synchrotron vacuum ultraviolet (SVUV) photoionization (PI) molecular-beam mass spectrometry (MBMS) for a cross-validation of the identification of important LT species. Experimental results indicate that DEE is very reactive; it starts to react around 425 K. DEE exhibits an unusual oxidation behavior with two negative temperature coefficient (NTC) zones in the JSR study. Because of this two-NTC observation, additional experiments were performed with a plug flow reactor (PFR) combined with electron ionization (EI)-MBMS, confirming this behavior in the two types of reactor. Moreover, about 20 oxidation species in C1-C4 range were detected with several intermediates containing 2-3 O-atoms. Acetic acid is found to peak at 525 K with a very large amount, suggesting that it is a key species in the early stage of DEE's LT oxidation. Possible DEE-consumption paths leading to acetic acid formation could play an important role in the oxidation mechanism of DEE. A new model is proposed based on the present experimental observations to include new primary LT reaction paths. The model reproduces the experimental phenomena quite well and enhances the understanding of the two-NTC-zone occurrence and of intermediates containing 2-3 O-atoms during the LT oxidation of DEE.
- Published
- 2018
16. The patient assignment problem in home health care: using a data-driven method to estimate the travel times of care givers
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Evren Sahin, J. George Shanthikumar, Andrea Matta, Semih Yalçındağ, Dipartimento di Meccanica Politecnico di Milano, HEC Montréal (HEC Montréal), School of Mechanical Engineering Shanghai Jiao Tong University, Shanghai Jiao Tong University [Shanghai], Laboratoire Génie Industriel - EA 2606 (LGI), CentraleSupélec, Krannert School of Management, and Purdue University [West Lafayette]
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Estimation ,Service (business) ,0209 industrial biotechnology ,021103 operations research ,Computer science ,0211 other engineering and technologies ,Kernel regression ,Resource assignment ,Workload ,02 engineering and technology ,Management Science and Operations Research ,Service provider ,Strategic human resource planning ,Industrial and Manufacturing Engineering ,3. Good health ,Data-driven ,[SPI]Engineering Sciences [physics] ,Home health care ,020901 industrial engineering & automation ,Operations management ,[MATH]Mathematics [math] ,Set (psychology) ,Assignment problem - Abstract
International audience; Home health care is one of the recent service systems where human resource planning has a great importance. The assignment of patients to care givers is a relevant issue that the home health care service provider must address before generating the daily routes. The assignment decision is typically made without knowing the visiting sequence, which creates some uncertainties and disparities regarding the effective workload of care givers. However, taking into account travel times in the care giver workload while solving the assignment problem is not straightforward, because travel times can also be affected by clinical conditions of patients and their homes. Providing good travel time estimates that would be used in the assignment decision is the specific topic this paper focuses on. In particular, we propose a data-driven method to estimate the travel times of care givers in the & Semih Yalçındag ˘ assignment problem when their routes are not available yet. The method, based on the Kernel regression technique, uses the travel times observed from previous periods to estimate the time necessary for visiting a set of patients located in specific geographical locations. The main advantage offered by this technique is the empirical modelling of the travel routes generated by care givers. Numerical results based on realistic problem instances indicate that the proposed estimation method performs better than the average value and k-nearest neighbor search methods and can be successfully used in a two-stage approach that first assigns patients to care givers and then defines their routes.
- Published
- 2015
17. A Fuzzy Knowledge Fusion Framework for Terms Conflict Resolution in Concurrent Engineering
- Author
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Aicha Seklouli Sekhari, Xiao Hu, Yinghong Peng, Zhaomin Cao, Jie Hu, Shanghai Jiao Tong University [Shanghai], School of Mechanical Engineering Shanghai Jiao Tong University, Décision et Information pour les Systèmes de Production (DISP), Université Lumière - Lyon 2 (UL2)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA), and School of Mechanical Engineering
- Subjects
Concurrent engineering ,Computer science ,business.industry ,General Engineering ,02 engineering and technology ,[INFO.INFO-IA]Computer Science [cs]/Computer Aided Engineering ,Data science ,Fuzzy logic ,Computer Science Applications ,Terminology ,Conceptual design ,020204 information systems ,Modeling and Simulation ,Similarity (psychology) ,Conflict resolution ,0202 electrical engineering, electronic engineering, information engineering ,Design process ,020201 artificial intelligence & image processing ,Artificial intelligence ,business ,ComputingMilieux_MISCELLANEOUS ,Natural language - Abstract
Due to the increased complexity of engineering products and design process, concurrent engineering practices still face enormous challenges. Design teams often provide the knowledge involving multiple disciplines in natural language at conceptual design stage. As a result, conflicts often arise during communications. To increase the efficiency of design process, it is necessary to avoid interpretation conflicts. This article presents a system framework to resolve terminology conflicts. First, a semantic hierarchical structure of knowledge is proposed. Knowledge is decomposed into terms and predicates. Second, a fuzzy knowledge fusion framework is proposed to identify and resolve terminology conflicts. The conflict is resolved by unifying the usage of terminologies. By using the fuzzy linguistic computational model based on extension principle to measure the similarity of terms, the terminology conflict problem is converted into a linguistic decision-making problem. Finally, the methodology is applied to a piece of automotive electronics knowledge. The best term to describe electronic control unit is identified.
- Published
- 2011
18. Experimental and kinetic modeling study of styrene combustion
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Philippe Dagaut, Fei Qi, Jiuzhong Yang, Wenhao Yuan, Yuyang Li, School of Mechanical Engineering Shanghai Jiao Tong University, Shanghai Jiao Tong University [Shanghai], Institut de Combustion, Aérothermique, Réactivité et Environnement (ICARE), Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut des Sciences de l'Ingénierie et des Systèmes (INSIS), National Synchrotron Radiation Laboratory (NSRL), and University of Science and Technology of China [Hefei] (USTC)
- Subjects
ignition delay ,General Chemical Engineering ,Inorganic chemistry ,General Physics and Astronomy ,Energy Engineering and Power Technology ,010402 general chemistry ,Photochemistry ,Mole fraction ,Combustion ,7. Clean energy ,01 natural sciences ,Ethylbenzene ,Styrene ,chemistry.chemical_compound ,0103 physical sciences ,Benzene ,ComputingMilieux_MISCELLANEOUS ,010304 chemical physics ,[SPI.FLUID]Engineering Sciences [physics]/Reactive fluid environment ,General Chemistry ,kinetic modeling ,Toluene ,0104 chemical sciences ,[CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry ,Fuel Technology ,chemistry ,Phenylacetylene ,13. Climate action ,jet-stirred reactor ,styrene ,Stoichiometry - Abstract
The aim of this work is to report new experimental data on styrene combustion and develop a kinetic model for styrene combustion. Three laminar premixed flames of styrene with equivalence ratios of 0.75, 1.00 and 1.70 were studied at low pressure (0.0395 atm) using synchrotron vacuum ultraviolet photoionization mass spectrometry. The JSR oxidation of styrene/benzene mixtures with three equivalence ratios of 0.50, 1.00, and 1.50 was studied at atmospheric pressure using gas chromatography. The mole fraction profiles of flame species and oxidation species were measured. A kinetic model of styrene combustion with 290 species and 1786 reactions was developed from our recently reported toluene model, and was validated on the new experimental data from this work and previous ignition delay time data. The O-atom attack reactions, H-atom abstraction reactions and other H-atom attack reactions were found to dominate the consumption of styrene. In particular, the O-atom attack reactions on the double bond of styrene play an important role in the JSR oxidation and the lean and stoichiometric flames, while the pyrolytic reactions have increasing contributions as the equivalence ratio increases. The phenyl radical plays a crucial role in the decomposition of styrene since it affords most of the reaction fluxes from styrene. In the aromatics growth process, phenylacetylene, the 1-phenylvinyl radical, the phenyl radical, and styrene serve as major precursors of polycyclic aromatic hydrocarbons (PAHs), leading to the high sooting tendency of styrene compared to toluene and ethylbenzene.
- Published
- 2015
19. Investigation on the pyrolysis and oxidation of toluene over a wide range conditions. I. Flow reactor pyrolysis and jet stirred reactor oxidation
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Jiuzhong Yang, Philippe Dagaut, Fei Qi, Wenhao Yuan, Yuyang Li, School of Mechanical Engineering Shanghai Jiao Tong University, Shanghai Jiao Tong University [Shanghai], Institut de Combustion, Aérothermique, Réactivité et Environnement (ICARE), Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut des Sciences de l'Ingénierie et des Systèmes (INSIS), National Synchrotron Radiation Laboratory (NSRL), and University of Science and Technology of China [Hefei] (USTC)
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Toluene oxidation ,Kinetic modeling ,General Chemical Engineering ,Analytical chemistry ,General Physics and Astronomy ,Energy Engineering and Power Technology ,Combustion ,Mass spectrometry ,Mole fraction ,7. Clean energy ,law.invention ,chemistry.chemical_compound ,law ,Flame ionization detector ,ComputingMilieux_MISCELLANEOUS ,Chemistry ,Thermal conductivity detector ,[SPI.FLUID]Engineering Sciences [physics]/Reactive fluid environment ,General Chemistry ,equipment and supplies ,pyrolysis ,Toluene ,[CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry ,Fuel Technology ,jet-stirred reactor ,Pyrolysis - Abstract
The pyrolysis of toluene was studied in a flow reactor at pressures from 5 to 760 Torr and temperatures from 1100 to 1730 K using synchrotron vacuum ultraviolet photoionization mass spectrometry. The pyrolysis species and intermediates, including some radicals, isomers and large PAHs, were identified and their mole fraction profiles were evaluated as the function of heating temperature. The oxidation of toluene was investigated in a jet stirred reactor (JSR) at the pressure of 10 atm, residence time of 0.6 s, equivalence ratios of 0.5, 1.0 and 1.5, and temperatures from 950 to 1200 K using gas chromatography combined with flame ionization detector, thermal conductivity detector and mass spectrometry. The concentration profiles of oxidation products as the function of heating temperature were measured. Based on recent theoretical progresses, a detailed kinetic model of toluene combustion with 272 species and 1698 reactions was developed to reproduce the decomposition of toluene and growth of aromatics in both the flow reactor pyrolysis and JSR oxidation. The rate of production analysis and the sensitivity analysis reveal that benzyl and fulvenallenyl radicals play crucial roles in the decomposition of toluene and formation of polycyclic aromatic hydrocarbons (PAHs).
- Published
- 2015
20. Investigation on the pyrolysis and oxidation of toluene over a wide range conditions. II. A comprehensive kinetic modeling study
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Philippe Dagaut, Yuyang Li, Wenhao Yuan, Jiuzhong Yang, Fei Qi, School of Mechanical Engineering Shanghai Jiao Tong University, Shanghai Jiao Tong University [Shanghai], Institut de Combustion, Aérothermique, Réactivité et Environnement (ICARE), Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut des Sciences de l'Ingénierie et des Systèmes (INSIS), National Synchrotron Radiation Laboratory (NSRL), and University of Science and Technology of China [Hefei] (USTC)
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Jet-stirred reactor ,Work (thermodynamics) ,Toluene oxidation ,Kinetic modeling ,General Chemical Engineering ,General Physics and Astronomy ,Energy Engineering and Power Technology ,Combustion ,7. Clean energy ,chemistry.chemical_compound ,synchrotron ,Organic chemistry ,Shock tube ,ComputingMilieux_MISCELLANEOUS ,[SPI.FLUID]Engineering Sciences [physics]/Reactive fluid environment ,Laminar flow ,General Chemistry ,pyrolysis ,Toluene ,[CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry ,Fuel Technology ,chemistry ,Chemical engineering ,Alkylbenzenes ,Pyrolysis - Abstract
The flow reactor pyrolysis of toluene from low to atmospheric pressures and jet stirred reactor oxidation of toluene at high pressure have been studied in Part I of this serial work. The targets in this part are to collect and review the experimental data of toluene pyrolysis and oxidation reported in recent years, and validate the kinetic model of toluene combustion developed in Part I. The vast amount of data used in this work mainly include species profiles in shock tube pyrolysis and oxidation, flow reactor oxidation and low pressure premixed laminar flames, and global combustion parameters such as ignition delay times and laminar flame speeds. Along with the validation of new pyrolysis and oxidation data in Part I, a wide range of conditions from low to high temperatures, subatmospheric to high pressures, very lean to pyrolysis conditions were validated in this work. The satisfactory reproduction of these data demonstrates that the present model can be used in combustion simulation of surrogate fuels containing toluene and as a reliable basis to develop kinetic models of large alkylbenzenes and bicyclic aromatics.
- Published
- 2015
21. A comprehensive experimental and kinetic modeling study of ethylbenzene combustion
- Author
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Wenhao Yuan, Yuyang Li, Gaëlle Pengloan, Casmir Togbé, Philippe Dagaut, Fei Qi, School of Mechanical Engineering Shanghai Jiao Tong University, Shanghai Jiao Tong University [Shanghai], Institut de Combustion, Aérothermique, Réactivité et Environnement (ICARE), Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut des Sciences de l'Ingénierie et des Systèmes (INSIS), National Synchrotron Radiation Laboratory (NSRL), and University of Science and Technology of China [Hefei] (USTC)
- Subjects
Jet-stirred reactor ,Kinetic modeling ,[SPI.FLUID]Engineering Sciences [physics]/Reactive fluid environment ,General Chemical Engineering ,General Physics and Astronomy ,Energy Engineering and Power Technology ,02 engineering and technology ,General Chemistry ,021001 nanoscience & nanotechnology ,Ethylbenzene ,[CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry ,Fuel Technology ,020401 chemical engineering ,0204 chemical engineering ,0210 nano-technology ,ComputingMilieux_MISCELLANEOUS ,combustion - Abstract
International audience
22. Improved Liver Intravital Microscopic Imaging Using a Film-Assisted Stabilization Method.
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Xu L, Feng X, Wang D, Gao F, Feng C, Shan Q, Wang G, Yang F, Zhang J, Hou J, Sun D, and Wang T
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- Animals, Mice, Vibration, Phagocytosis, Liposomes chemistry, Kupffer Cells cytology, Mice, Inbred C57BL, Male, Liver diagnostic imaging, Intravital Microscopy methods
- Abstract
Intravital microscopy (IVM) is a valuable method for biomedical characterization of dynamic processes, which has been applied to many fields such as neuroscience, oncology, and immunology. During IVM, vibration suppression is a major challenge due to the inevitable respiration and heartbeat from live animals. In this study, taking liver IVM as an example, we have unraveled the vibration inhibition effect of liquid bridges by studying the friction characteristics of a moist surface on the mouse liver. We confirmed the presence of liquid bridges on the liver through fluorescence imaging, which can provide microscale and nondestructive liquid connections between adjacent surfaces. Liquid bridges were constructed to sufficiently stabilize the liver after abdominal dissection by covering it with a polymer film, taking advantage of the high adhesion properties of liquid bridges. We further prototyped a microscope-integrated vibration-damping device with adjustable film tension to simplify the sample preparation procedure, which remarkably decreased the liver vibration. In practical application scenarios, we observed the process of liposome phagocytosis by liver Kupffer cells with significantly improved image and video quality. Collectively, our method not only provided a feasible solution to vibration suppression in the field of IVM, but also has the potential to be applied to vibration damping of precision instruments or other fields that require nondestructive ″soft″ vibration damping.
- Published
- 2024
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23. Chirality Engineering of Nanostructured Copper Oxide for Enhancing Oxygen Evolution from Water Electrolysis.
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Li Y, Qiu L, Tian R, Liu Z, Yao L, Huang L, Li W, Wang Y, Wang T, and Zhou B
- Abstract
The exploration of a new conceptual strategy for improving the oxygen evolution reaction (OER) of earth-abundant electrocatalysts is critical. In this study, chiral copper oxide nanoflower is explored by a self-assembly method. The characterization suggests the chiral structure originates from the crystal plane-level helical stack of the secondary nanosheets. Of note, the assembly illustrates a record-high degree of spin polarization of 96%, indicating the ideal alignment of electron spin. Moreover, density function theory calculations show the chiral structure reducing the reaction energy barrier (REB) while switching the potential-determining step from *O→*OOH to *OH→*O. Together with the enhanced electrochemical active surface area and accelerated charge transfer, the production of ground-state triplet O
2 is improved via a spin-forbidden route that involves the singlet H2 O/OH•. Consequently, the chiral nanoflower shows a overpotential of 308 mV at 10 mA cm-2 and a Tafel slope of 93.5 mV dec-1 , which is even superior to the commercial RuO2 (310 mV, 101 mV dec-1 ). This study presents a new strategy for improving the OER activity by simultaneously enhancing electronic properties and lowering the REB of an non-noble electrocatalyst via chirality engineering., (© 2024 Wiley‐VCH GmbH.)- Published
- 2024
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24. Water-Triboelectrification-Complemented Moisture Electric Generator.
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Li F, Zhao J, Li B, Han Z, Guo L, Han P, Kim HH, Su Y, Zhu LM, and Shen D
- Abstract
Energy harvesting from ubiquitous natural water vapor based on moisture electric generator (MEG) technology holds great potential to power portable electronics, the Internet of Things, and wireless transmission. However, most devices still encounter challenges of low output, and a single MEG complemented with another form of energy harvesting for achieving high power has seldom been demonstrated. Herein, we report a flexible and efficient hybrid generator capable of harvesting moisture and tribo energies simultaneously, both from the source of water droplets. The moisture electric and triboelectric layers are based on a water-absorbent citric acid (CA)-mediated polyglutamic acid (PGA) hydrogel and porous electret expanded polytetrafluoroethylene (E-PTFE), respectively. Such a waterproof E-PTFE film not only enables efficient triboelectrification with water droplets' contact but also facilitates water vapor to be transferred into the hydrogel layer for moisture electricity generation. A single hybrid generator under water droplets' impact delivers a DC voltage of 0.55 V and a peak current density of 120 μA cm
-2 from the MEG, together with a simultaneous AC output voltage of 300 V and a current of 400 μA from the complementary water-based triboelectric generator (TEG) side. Such a hybrid generator can work even under harsh wild environments with 5 °C cold and saltwater impacts. Significantly, an optical alarm and wireless communication system for wild, complex, and emergency scenarios is demonstrated with power from the hybrid generators. This work expands the applications of water-based electricity generation technologies and provides insight into harvesting multiple potential energies in the natural environment with high output.- Published
- 2024
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25. Crystalline-Amorphous IrO x Supported on Perovskite Nanotubes for pH-Universal OER.
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Li X, Wang Z, Peng Z, Cheng J, Zheng F, Wang Y, Tian Y, Chi B, Wei G, and Zhang J
- Abstract
Designing catalysts with desirable oxygen evolution reaction (OER) performance under pH-universal conditions is of great significance to promote the development of hydrogen production. Herein, we successfully synthesized a crystalline-amorphous IrO
x supported on perovskite oxide nanotubes to obtain IrOx @La0.6 Ca0.4 Fe0.8 Ni0.2 O3 with superior OER performance in whole pH media. The overpotential of the IrOx @La0.6 Ca0.4 Fe0.8 Ni0.2 O3 catalyst in media of pH 14, 7.2, and 1 has been demonstrated to be 120, 400, and 143 mV, respectively, with no significant element dissolution as well as double-layer capacitance decay after the durability test. Through comparative experiments with IrOx @CNT and the physical mixture of IrOx and La0.6 Ca0.4 Fe0.8 Ni0.2 O3 , it is found that the strong metal-support interaction (SMSI) in IrOx @La0.6 Ca0.4 Fe0.8 Ni0.2 O3 makes IrOx exist in an amorphous state rich in Ir3+ , which is closely associated with the surface-active species Ir-OH. Through the regulation of Ir by a perovskite oxide support at the heterointerface, the reaction breaks through the limitation of the adsorbate evolution mechanism (AEM) and converts to a lattice-oxygen-mediated mechanism (LOM), which was fully demonstrated by the addition of the probe tetramethylammonium cation (TMA+ ), a LOM reaction intermediate, to the electrolyte. This work fills the research gap of perovskite oxide supported Ir-based catalysts with heterogeneous structures, providing an excellent strategy for the structural design of efficient pH-universal OER catalysts for hydrogen production systems.- Published
- 2024
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- View/download PDF
26. Avian-inspired embodied perception in biohybrid flapping-wing robotics.
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Li Q, Tan T, Wang B, and Yan Z
- Subjects
- Animals, Biomechanical Phenomena, Mechanoreceptors physiology, Neural Networks, Computer, Proprioception physiology, Robotics, Flight, Animal physiology, Feathers physiology, Birds physiology, Wings, Animal physiology, Aircraft
- Abstract
Avian feather intricate adaptable architecture to wing deformations has catalyzed interest in feathered flapping-wing aircraft with high maneuverability, agility, and stealth. Yet, to mimic avian integrated somatic sensation within stringent weight constraints, remains challenging. Here, we propose an avian-inspired embodied perception approach for biohybrid flapping-wing robots. Our feather-piezoelectric mechanoreceptor leverages feather-based vibration structures and flexible piezoelectric materials to refine and augment mechanoreception via coupled oscillator interactions and robust microstructure adhesion. Utilizing convolutional neural networks with the grey wolf optimizer, we develop tactile perception of airflow velocity and wing flapping frequency proprioception. This method also senses pitch angle via airflow direction and detects wing morphology through feather collisions. Our low-weight, accurate perception of flapping-wing robot flight states is validated by motion capture. This investigation constructs a biomechanically integrated embodied perception system in flapping-wing robots, which holds significant promise in reflex-based control of complex flight maneuvers and natural bird flight surveillance., (© 2024. The Author(s).)
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- 2024
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27. Parameter Optimization for Laser Peen Forming on 6005A-T6 Aluminum Alloy Plates to Enhance the Constrained Deformation of Integral Stiffened Plates.
- Author
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Jiang G, Zhou J, Wu J, Huang S, Meng X, and Hu Y
- Abstract
Multiscale parameter optimization for laser peen forming (LPF) on 6005A-T6 aluminum alloy plates was conducted through a combination of simulation and experimentation. By obtaining the optimal parameter, this study aims to explore the constrained deformation and forming laws of the integral stiffened plates. Detailed descriptions were provided regarding the dynamic response process and transient behavior of aluminum alloy plates under ultrahigh strain rates, along with an in-depth analysis of the stress evolution. The results reveal that laser beam diameter and laser beam energy can achieve large range forming, while the number of tracks facilitates the precise deformation adjustment. During the 12-track LPF process, there is an overall upward trend in deformation values accompanied by a dynamic increase in the bend curvature. After static relaxation, the deformation value recovers to 55.2% of the final bending curvature. The chord direction scanning of stiffened plates exhibits a larger bending curvature, indicating its greater forming capacity for large-sized single unfolding direction formation; whereas, the unfolding direction scanning of stiffened plates excels in achieving efficient integrated two-way forming.
- Published
- 2024
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28. A Globally Guided Dual-Arm Reactive Motion Controller for Coordinated Self-Handover in a Confined Domestic Environment.
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Geng Z, Yang Z, Xu W, Guo W, and Sheng X
- Abstract
Future humanoid robots will be widely deployed in our daily lives. Motion planning and control in an unstructured, confined, and human-centered environment utilizing dexterity and a cooperative ability of dual-arm robots is still an open issue. We propose a globally guided dual-arm reactive motion controller (GGDRC) that combines the strengths of global planning and reactive methods. In this framework, a global planner module with a prospective task horizon provides feasible guidance in a Cartesian space, and a local reactive controller module addresses real-time collision avoidance and coordinated task constraints through the exploitation of dual-arm redundancy. GGDRC extends the start-of-the-art optimization-based reactive method for motion-restricted dynamic scenarios requiring dual-arm cooperation. We design a pick-handover-place task to compare the performances of these two methods. Results demonstrate that GGDRC exhibits accurate collision avoidance precision (5 mm) and a high success rate (84.5%).
- Published
- 2024
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29. Ultra-High Sensitivity Anisotropic Piezoelectric Sensors for Structural Health Monitoring and Robotic Perception.
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Yin H, Li Y, Tian Z, Li Q, Jiang C, Liang E, and Guo Y
- Abstract
Monitoring minuscule mechanical signals, both in magnitude and direction, is imperative in many application scenarios, e.g., structural health monitoring and robotic sensing systems. However, the piezoelectric sensor struggles to satisfy the requirements for directional recognition due to the limited piezoelectric coefficient matrix, and achieving sensitivity for detecting micrometer-scale deformations is also challenging. Herein, we develop a vector sensor composed of lead zirconate titanate-electronic grade glass fiber composite filaments with oriented arrangement, capable of detecting minute anisotropic deformations. The as-prepared vector sensor can identify the deformation directions even when subjected to an unprecedented nominal strain of 0.06%, thereby enabling its utility in accurately discerning the 5 μm-height wrinkles in thin films and in monitoring human pulse waves. The ultra-high sensitivity is attributed to the formation of porous ferroelectret and the efficient load transfer efficiency of continuous lead zirconate titanate phase. Additionally, when integrated with machine learning techniques, the sensor's capability to recognize multi-signals enables it to differentiate between 10 types of fine textures with 100% accuracy. The structural design in piezoelectric devices enables a more comprehensive perception of mechanical stimuli, offering a novel perspective for enhancing recognition accuracy., (© 2024. The Author(s).)
- Published
- 2024
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30. Platinum-cobalt synergy redefines electrocatalytic lignin upgrading.
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Chen X, Zhou B, and Yan N
- Published
- 2024
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31. Author Correction: Non-equilibrium pathways to emergent polar supertextures.
- Author
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Stoica VA, Yang T, Das S, Cao Y, Wang HH, Kubota Y, Dai C, Padma H, Sato Y, Mangu A, Nguyen QL, Zhang Z, Talreja D, Zajac ME, Walko DA, DiChiara AD, Owada S, Miyanishi K, Tamasaku K, Sato T, Glownia JM, Esposito V, Nelson S, Hoffmann MC, Schaller RD, Lindenberg AM, Martin LW, Ramesh R, Matsuda I, Zhu D, Chen LQ, Wen H, Gopalan V, and Freeland JW
- Published
- 2024
- Full Text
- View/download PDF
32. 2D/3D registration based on biplanar X-ray and CT images for surgical navigation.
- Author
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Yang D, Shi H, Zeng B, and Chen X
- Abstract
Background and Objectives: Image-based 2D/3D registration is a crucial technology for fluoroscopy-guided surgical interventions. However, traditional registration methods relying on a single X-ray image into surgical navigation systems. This study proposes a novel 2D/3D registration approach utilizing biplanar X-ray images combined with computed tomography (CT) to significantly reduce registration and navigation errors. The method is successfully implemented in a surgical navigation system, enhancing its precision and reliability., Methods: First, we simultaneously register the frontal and lateral X-ray images with the CT image, enabling mutual complementation and more precise localization. Additionally, we introduce a novel similarity measure for image comparison, providing a more robust cost function for the optimization algorithm. Furthermore, a multi-resolution strategy is employed to enhance registration efficiency. Lastly, we propose a more accurate coordinate transformation method, based on projection and 3D reconstruction, to improve the precision of surgical navigation systems., Results: We conducted registration and navigation experiments using pelvic, spinal, and femur phantoms. The navigation results demonstrated that the feature registration errors (FREs) in the three experiments were 0.505±0.063 mm, 0.515±0.055 mm, and 0.577±0.056 mm, respectively. Compared to the point-to-point (PTP) registration method based on anatomical landmarks, our method reduced registration errors by 31.3%, 23.9%, and 26.3%, respectively., Conclusion: The results demonstrate that our method significantly reduces registration and navigation errors, highlighting its potential for application across various anatomical sites. Our code is available at: https://github.com/SJTUdemon/2D-3D-Registration., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)
- Published
- 2024
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33. An in-phase filter-based flux observation strategy for sensorless control of PMSMs.
- Author
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Zheng L, Tong Y, Karimi HR, and Huang B
- Abstract
Due to the complexity of determining the initial rotor flux and detecting errors, conventional rotor flux observation methods are easily affected by direct current (DC) components and harmonics. To address this issue, this paper proposes an in-phase filter (IPF)-based rotor flux observation strategy for sensorless control of permanent magnet synchronous machines (PMSMs). The core components of the IPF consist of a double second-order generalized integrator (DSOGI) and a phase angle compensation transfer function (PACTF). The DSOGI provides a accurate electrical angular frequency, while the PACTF implements a phase correction to the v
q signals. By employing IPF structure, accurate observations for rotor flux, electronic speed, and rotor position are achieved, which can be effectively used in the sensorless control of PMSMs, eliminating the need for magnitude and phase compensations. Finally, the proposed observation strategy is applied to an experimental bench of a PMSM, and its effectiveness is illustrated by experimental results. From experimental results, it can be concluded that the IPF is significantly better than the LPF, and 5% more accurate than the observer based on cascade second-order generalized integral(CSOGI) overall.' signals. By employing IPF structure, accurate observations for rotor flux, electronic speed, and rotor position are achieved, which can be effectively used in the sensorless control of PMSMs, eliminating the need for magnitude and phase compensations. Finally, the proposed observation strategy is applied to an experimental bench of a PMSM, and its effectiveness is illustrated by experimental results. From experimental results, it can be concluded that the IPF is significantly better than the LPF, and 5% more accurate than the observer based on cascade second-order generalized integral(CSOGI) overall., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)- Published
- 2024
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34. Revisiting the sound absorption mechanisms of a finite flexible perforated panel absorber using a numerical approach.
- Author
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Li J, Zhao P, Wang P, and Yang C
- Abstract
This study investigates the sound absorption mechanisms of a finite flexible perforated panel absorber. Different from existing work where the mechanisms were often investigated by comparing the sound absorption coefficient curves of different absorber configurations, a numerical approach, called virtual impedance tube (VIT) technique, is developed and used for the analysis. One advantage of this technique is the vast dataset generated can be used to investigate the sound absorption mechanisms from an energy standpoint. The developed VIT technique is first validated using the impedance tube test, where a proportion-integration-differentiation control algorithm is developed to maintain the incident sound at a desired sound pressure level. Then, the sound absorption mechanisms at three absorption peaks, i.e., hole-cavity controlled, panel-cavity controlled, and panel controlled, are investigated and the dominant energy dissipation mechanism at different sound pressure levels (SPLs) is revealed. Finally, an impedance model that takes account of the panel vibration and is applicable to various SPLs is proposed and validated., (© 2024 Acoustical Society of America.)
- Published
- 2024
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35. Non-equilibrium pathways to emergent polar supertextures.
- Author
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Stoica VA, Yang T, Das S, Cao Y, Wang HH, Kubota Y, Dai C, Padma H, Sato Y, Mangu A, Nguyen QL, Zhang Z, Talreja D, Zajac ME, Walko DA, DiChiara AD, Owada S, Miyanishi K, Tamasaku K, Sato T, Glownia JM, Esposito V, Nelson S, Hoffmann MC, Schaller RD, Lindenberg AM, Martin LW, Ramesh R, Matsuda I, Zhu D, Chen LQ, Wen H, Gopalan V, and Freeland JW
- Abstract
Ultrafast stimuli can stabilize metastable states of matter inaccessible by equilibrium means. Establishing the spatiotemporal link between ultrafast excitation and metastability is crucial to understand these phenomena. Here we utilize single-shot optical pump-X-ray probe measurements to capture snapshots of the emergence of a persistent polar vortex supercrystal in a heterostructure that hosts a fine balance between built-in electrostatic and elastic frustrations by design. By perturbing this balance with photoinduced charges, an initially heterogeneous mixture of polar phase disorders within a few picoseconds, leading to a state composed of disordered ferroelectric and suppressed vortex orders. On the picosecond-nanosecond timescales, transient labyrinthine fluctuations develop, accompanied by the recovery of the vortex order. On longer timescales, these fluctuations are progressively quenched by dynamical strain modulations, which drive the collective emergence of a single vortex supercrystal phase. Our results, corroborated by dynamical phase-field modelling, reveal non-equilibrium pathways following the ultrafast excitation of designer systems to persistent metastability., (© 2024. UChicago Argonne, LLC, Operator of Argonne National Laboratory, and the Authors, under exclusive licence to Springer Nature Limited.)
- Published
- 2024
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36. A bidirectional framework for fracture simulation and deformation-based restoration prediction in pelvic fracture surgical planning.
- Author
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Zeng B, Wang H, Tao X, Shi H, Joskowicz L, and Chen X
- Subjects
- Humans, Computer Simulation, Surgery, Computer-Assisted methods, Fractures, Bone diagnostic imaging, Fractures, Bone surgery, Pelvic Bones diagnostic imaging, Pelvic Bones injuries, Pelvic Bones surgery, Tomography, X-Ray Computed
- Abstract
Pelvic fracture is a severe trauma with life-threatening implications. Surgical reduction is essential for restoring the anatomical structure and functional integrity of the pelvis, requiring accurate preoperative planning. However, the complexity of pelvic fractures and limited data availability necessitate labor-intensive manual corrections in a clinical setting. We describe in this paper a novel bidirectional framework for automatic pelvic fracture surgical planning based on fracture simulation and structure restoration. Our fracture simulation method accounts for patient-specific pelvic structures, bone density information, and the randomness of fractures, enabling the generation of various types of fracture cases from healthy pelvises. Based on these features and on adversarial learning, we develop a novel structure restoration network to predict the deformation mapping in CT images before and after a fracture for the precise structural reconstruction of any fracture. Furthermore, a self-supervised strategy based on pelvic anatomical symmetry priors is developed to optimize the details of the restored pelvic structure. Finally, the restored pelvis is used as a template to generate a surgical reduction plan in which the fragments are repositioned in an efficient jigsaw puzzle registration manner. Extensive experiments on simulated and clinical datasets, including scans with metal artifacts, show that our method achieves good accuracy and robustness: a mean SSIM of 90.7% for restorations, with translational errors of 2.88 mm and rotational errors of 3.18°for reductions in real datasets. Our method takes 52.9 s to complete the surgical planning in the phantom study, representing a significant acceleration compared to standard clinical workflows. Our method may facilitate effective surgical planning for pelvic fractures tailored to individual patients in clinical settings., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)
- Published
- 2024
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37. Using a Biofeedback-Based Mindfulness Practice System to Enhance Mindfulness and Alleviate Anxiety in College Students: A Randomized Controlled Trial.
- Author
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Mingxuan W, Ting H, Chenqi Z, Ningning Z, Hao C, Hongtao Z, Shuo L, and Yang G
- Subjects
- Humans, Male, Female, Universities organization & administration, Surveys and Questionnaires, Young Adult, Adult, Mindfulness methods, Biofeedback, Psychology methods, Biofeedback, Psychology instrumentation, Students psychology, Students statistics & numerical data, Anxiety therapy, Anxiety psychology
- Abstract
Objective: College students experience intense anxiety, for which biofeedback mindfulness techniques show effectiveness in relief. However, typical biofeedback products often lead to user fatigue and boredom because of a single or fixed feedback and lack of focus on mindfulness enhancement. Materials and Methods: In this research, we developed Mindjourney, a VR-based respiratory feedback mindfulness system, designed to enhance mindfulness and alleviate anxiety through continuous/noncontinuous feedback and nonjudgmental reward/punishment for self-perception and attention management. A randomized controlled trial involved 72 college students, split equally into short-term ( n = 34, age: 23.11 ± 1.729) and 4-week long-term ( n = 38, age: 24.12 ± 1.408) groups, with equal randomization for intervention and control groups. Pre/postintervention tests were measured by using Trait Anxiety Inventory (TAI) and Five Facet Mindfulness Questionnaire (FFMQ) for long-term groups and Galvanic Skin Response and State Anxiety Inventory (SAI) for short-term groups. Results: Results showed that the long-term intervention group showed a significant increase in mindfulness ( P = 0.001 for FFMQ total score). Furthermore, observe and act with awareness subscales showed significant increase after intervention ( P = 0.034 for observe , P < 0.001 for act with awareness ) compared with the control group. Both intervention groups demonstrated a significant decrease in anxiety levels compared with the control groups ( P = 0.049 for SAI, P = 0.01 for TAI). Moreover, participants expressed high interest in this biofeedback mindfulness system and willingness for long-term usage. Conclusion: The proposed biofeedback mindfulness practice system could potentially facilitate mindfulness practice and serve as a convenient tool for anxiety relief in campus college students.
- Published
- 2024
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38. Ionic Hydrogel-Based Moisture Electric Generators for Underwater Electronics.
- Author
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Shen D, Li F, Zhao J, Wang R, Li B, Han Z, Guo L, Han P, Yang D, Kim HH, Su Y, Gong Z, and Zhu L
- Abstract
Ubiquitous moisture is of particular interest for sustainable power generation and self-powered electronics. However, current moisture electric generators (MEGs) can only harvest moisture energy in the air, which tremendously limits the energy harvesting efficiency and practical application scenarios. Herein, the operationality of MEG from air to underwater environment, through a sandwiched engineered-hydrogel device with an additional waterproof breathable membrane layer allowing water vapor exchange while preventing liquid water penetration, is expanded. Underwater environment, the device can spontaneously deliver a voltage of 0.55 V and a current density of 130 µA cm
-2 due to the efficient ion separation assisted by negative ions confinement in hydrogel networks. The output can be maintained even under harsh underwater environment with 10% salt concentration, 1 m s-1 disturbing flow, as well as >40 kPa hydraulic pressure. The engineered hydrogel used for MEG also exhibits excellent self-healing ability, flexibility, and biocompatibility. As the first demonstration of practical applications in self-powered underwater electronics, the MEG device is successfully powering a wireless emitter for remote communication in water. This new type of MEG offers an innovative route for harvesting moisture energy underwater and holds promise in the creation of a new range of innovative electronic devices for marine Internet-of-Things., (© 2024 The Author(s). Advanced Science published by Wiley‐VCH GmbH.)- Published
- 2024
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39. A Real-Time Global Re-Localization Framework for a 3D LiDAR-Based Navigation System.
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Chai Z, Liu C, and Xiong Z
- Abstract
Place recognition is widely used to re-localize robots in pre-built point cloud maps for navigation. However, current place recognition methods can only be used to recognize previously visited places. Moreover, these methods are limited by the requirement of using the same types of sensors in the re-localization process and the process is time consuming. In this paper, a template-matching-based global re-localization framework is proposed to address these challenges. The proposed framework includes an offline building stage and an online matching stage. In the offline stage, virtual LiDAR scans are densely resampled in the map and rotation-invariant descriptors can be extracted as templates. These templates are hierarchically clustered to build a template library. The map used to collect virtual LiDAR scans can be built either by the robot itself previously, or by other heterogeneous sensors. So, an important feature of the proposed framework is that it can be used in environments that have never been visited by the robot before. In the online stage, a cascade coarse-to-fine template matching method is proposed for efficient matching, considering both computational efficiency and accuracy. In the simulation with 100 K templates, the proposed framework achieves a 99% success rate and around 11 Hz matching speed when the re-localization error threshold is 1.0 m. In the validation on The Newer College Dataset with 40 K templates, it achieves a 94.67% success rate and around 7 Hz matching speed when the re-localization error threshold is 1.0 m. All the results show that the proposed framework has high accuracy, excellent efficiency, and the capability to achieve global re-localization in heterogeneous maps.
- Published
- 2024
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40. Mechanical effect of different patterns for preparation of orthodontic appliances: An experimental study.
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Tian S, Dai J, Ahmad W, Liang K, Tan Q, Deng H, Jiang F, Xiong J, Cao J, and Xia Z
- Subjects
- Orthodontic Appliances, Stress, Mechanical, Orthodontic Appliance Design, Stainless Steel chemistry, Orthodontic Wires, Materials Testing, Dental Stress Analysis
- Abstract
Archwire bending is the key to orthodontic treatment, and multi-time bendings are inevitable during manual and robotic automated bending. The purpose of this paper is to quantitatively evaluate the mechanical effects of the different preparation modes and to compare the mechanical properties of the orthodontic loops in one and multiple bends. Three types of typical stainless steel orthodontic loops (vertical loop, T-loop, and L-loop) were used to quantify the mechanical effect of patterns for preparation by experimental comparison between loops with different bending times by using an orthodontic force tester (OFT). The results were statistically analyzed by t-test. The fracture test of the stainless steel archwire was also carried out, and the bending times at fracture were recorded. Results of the tests indicate that one-time and multi-time bending have a significant mechanical effect on orthodontic appliances. Multi-time bending causes significant mechanical decreases and can damage the appliances.
- Published
- 2024
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41. Comprehensive Assessment and Optimization of a Middle-Arch Dual-Channel Municipal Solid Waste Incinerator Using Numerical Simulation Methods.
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Zhou H, Zhang R, Wang L, and Luo Y
- Abstract
The present study focuses on a middle-arch dual-channel municipal solid waste (MSW) incinerator facing issues of high NO
x emission and overheating. To address these problems and optimize the incinerator, an advanced numerical simulation method was employed to comprehensively assess its bed combustion, freeboard combustion, and NOx emission characteristics. A multiphase fuel bed model considering large-particle characteristics of MSW was developed, coupled with a three-dimensional (3D) model for combustion in freeboard. The analysis revealed that the observed issues stem from multiple factors, including primary-to-secondary air ratio, flame propagation in bed, release of volatiles from bed, and distribution and mixing of components in freeboard. Reducing the proportion of primary air and correspondingly increasing secondary air effectively alleviated the localized overheating in the furnace and reduced NOx emission. Further adjustments to the distribution of primary air in three stages delaying air supply toward the burnout stage, together with the decrease in the grate movement speed, can better control the amount and speciation of N released from the bed. Implementing a counterflow mixing strategy with NH3 in the front channel and NO in the rear channel can greatly reduce the original NOx emission concentration to 95.94 mg/(N·m3 ), as predicted by a numerical simulation. Subsequent practical adjustments to an actual incinerator led to notable improvements, clearly optimizing the localized high-temperature issues at various locations, especially the front channel suffering severe slagging problems, with the temperature reduced from 1118 to 957 °C. Meanwhile, NOx emission concentration decreased from 200 mg/(N·m3 ) to around 50 mg/(N·m3 ), with no negative effect on the boiler load., Competing Interests: The authors declare no competing financial interest., (© 2024 The Authors. Published by American Chemical Society.)- Published
- 2024
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42. Green Syngas Production from Natural Lignin, Sunlight, and Water over Pt-Decorated InGaN Nanowires.
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Yu T, Li J, Li Y, Qiu L, Pan H, Zhu L, Huang Z, and Zhou B
- Abstract
Transformation of lignin to syngas can turn waste into treasure yet remains a tremendous challenge because of its naturally evolved stubborn structure. In this work, light-driven reforming of natural lignin in water for green syngas production is explored using Pt-decorated InGaN nanowires. The spectroscopic characterizations, isotope, and model compound experiments, as well as density function theory calculation, disclose that among a variety of groups including aromatic ring, -OH, -OCH
3 , -C3 H7 with complex chemical bonds of O-H, C-H, C-C, C-O, etc., InGaN nanowires are cooperative with Pt for preferably breaking the C-O bond of the rich O-CH3 group in lignin to liberating ⋅CH3 by photogenerated holes with a minimum dissociation energy of 2.33 eV. Syngas are subsequently yielded from the continuous evolution of ⋅CH3 and ⋅OH from photocatalytic reforming of lignin in water. Together with the superior optoelectronic attributes of Pt-decorated InGaN nanowires, the evolution rate of syngas approaches 43.4 mol ⋅ g-1 ⋅ h-1 with tunable H2 /CO ratios and a remarkable turnover number (TON) of 150, 543 mol syngas per mol Pt. Notably, the architecture demonstrates a high light efficiency of 12.1 % for syngas generation under focused light without any extra thermal input. Outdoor test ascertains the viability of producing syngas with the only inputs of natural lignin, water, and sunlight, thus presenting a low-carbon route for synthesizing transportation fuels and value-added chemicals., (© 2024 Wiley-VCH GmbH.)- Published
- 2024
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43. Ni-Doped Pr 0.7 Ba 0.3 MnO 3-δ Cathodes for Enhancing Electrolysis of CO 2 in Solid Oxide Electrolytic Cells.
- Author
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Shan F, Chen T, Ye L, and Xie K
- Abstract
Solid Oxide Electrolysis Cells (SOECs) can electro-reduce carbon dioxide to carbon monoxide, which not only effectively utilizes greenhouse gases, but also converts excess electrical energy into chemical energy. Perovskite-based oxides with exsolved metal nanoparticles are promising cathode materials for direct electrocatalytic reduction of CO
2 through SOECs, and have thus received increasing attention. In this work, we doped Pr0.7 Ba0.3 MnO3-δ at the B site, and after reduction treatment, metal nanoparticles exsolved and precipitated on the surface of the cathode material, thereby establishing a stable metal-oxide interface structure and significantly improving the electrocatalytic activity of the SOEC cathode materials. Through research, among the Pr0.7 Ba0.3 Mn1-x Nix O3-δ (PBMNx = 0-1) cathode materials, it has been found that the Pr0.7 Ba0.3 Mn0.9 Ni0.1 O3-δ (PBMN0.1 ) electrode material exhibits greater catalytic activity, with a CO yield of 5.36 mL min-1 cm-2 and a Faraday current efficiency of ~99%. After 100 h of long-term testing, the current can still remain stable and there is no significant change in performance. Therefore, the design of this interface has increasing potential for development.- Published
- 2024
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44. Motion Planning for a Legged Robot with Dynamic Characteristics.
- Author
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Liu X, Yang L, Chen Z, Zhong J, and Gao F
- Abstract
Legged soccer robots present a significant challenge in robotics owing to the need for seamless integration of perception, manipulation, and dynamic movement. While existing models often depend on external perception or static techniques, our study aims to develop a robot with dynamic and untethered capabilities. We have introduced a motion planner that allows the robot to excel in dynamic shooting and dribbling. Initially, it identifies and predicts the position of the ball using a rolling model. The robot then pursues the ball, using a novel optimization-based cycle planner, continuously adjusting its gait cycle. This enables the robot to kick without stopping its forward motion near the ball. Each leg is assigned a specific role (stance, swing, pre-kick, or kick), as determined by a gait scheduler. Different leg controllers were used for tailored tiptoe trajectory planning and control. We validated our approach using real-world penalty shot experiments (5 out of 12 successful), cycle adjustment tests (11 out of 12 successful), and dynamic dribbling assessments. The results demonstrate that legged robots can overcome onboard capability limitations and achieve dynamic mobility and manipulation., Competing Interests: Author Jiangwei Zhong was employed by the company Lenovo. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
- Published
- 2024
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45. Improving Thermosensitive Bioink Scaffold Fabrication with a Temperature-Regulated Printhead in Robot-Assisted In Situ Bioprinting System.
- Author
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Wang Z, Lin L, Li X, Zhang Q, Mi X, Xu B, Xu Y, Liu T, Shen Y, Wang Z, Xie N, and Wang J
- Abstract
In situ bioprinting enables precise 3D printing inside the human body using modified bioprinters with thermosensitive bioinks such as gelatin methacrylate (GelMA). However, these devices lack refined temperature-regulated mechanisms essential for ensuring bioink viscosity, as compared to traditional bio-3D printers. Addressing this challenge, this study presents a temperature-regulated printhead designed to improve the fabrication of thermosensitive bioink scaffolds in in situ bioprinting, integrated into a UR5 robotic arm. Featuring a closed-loop system, it achieves a temperature steady error of 1 °C and a response time of approximately 1 min. The effectiveness of the printer was validated by bioprinting multilayer lattice 3D bioscaffolds. Comparisons were made with or without temperature control using different concentrations of GelMA + LAP. The deformation of the bioscaffolds under both conditions was analyzed, and cell culture tests were conducted to verify viability. Additionally, the rheology and mechanical properties of GelMA were tested. A final preliminary in situ bioprinting experiment was conducted on a model of a damaged femur to demonstrate practical application. The fabrication of this printhead is entirely open source, facilitating easy modifications to accommodate various robotic arms. We encourage readers to advance this prototype for application in increasingly complex in situ bioprinting situations, especially those utilizing thermosensitive bioinks., Competing Interests: The authors declare no competing financial interest., (© 2024 The Authors. Published by American Chemical Society.)
- Published
- 2024
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46. Is the Apple Vision Pro the Ultimate Display? A First Perspective and Survey on Entering the Wonderland of Precision Medicine.
- Author
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Egger J, Gsaxner C, Luijten G, Chen J, Chen X, Bian J, Kleesiek J, and Puladi B
- Abstract
At the Worldwide Developers Conference in June 2023, Apple introduced the Vision Pro. The Apple Vision Pro (AVP) is a mixed reality headset; more specifically, it is a virtual reality device with an additional video see-through capability. The video see-through capability turns the AVP into an augmented reality (AR) device. The AR feature is enabled by streaming the real world via cameras on the (virtual reality) screens in front of the user's eyes. This is, of course, not unique and is similar to other devices, such as the Varjo XR-3 (Varjo Technologies Oy). Nevertheless, the AVP has some interesting features, such as an inside-out screen that can show the headset wearer's eyes to "outsiders," and a button on the top, called the "digital crown," that allows a seamless blend of digital content with the user's physical space by turning it. In addition, it is untethered, except for the cable to the battery, which makes the headset more agile, compared to the Varjo XR-3. This could actually come closer to "The Ultimate Display," which Ivan Sutherland had already sketched in 1965. After a great response from the media and social networks to the release, we were able to test and review the new AVP ourselves in March 2024. Including an expert survey with 13 of our colleagues after testing the AVP in our institute, this Viewpoint explores whether the AVP can overcome clinical challenges that AR especially still faces in the medical domain; we also go beyond this and discuss whether the AVP could support clinicians in essential tasks to allow them to spend more time with their patients., (©Jan Egger, Christina Gsaxner, Gijs Luijten, Jianxu Chen, Xiaojun Chen, Jiang Bian, Jens Kleesiek, Behrus Puladi. Originally published in JMIR Serious Games (https://games.jmir.org), 18.09.2024.)
- Published
- 2024
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47. Bio-inspired hierarchical wearable patch for fast sweat collection.
- Author
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Wu T, Yang P, Xie X, Cao X, Deng Y, Ding X, and Zhang Z
- Subjects
- Humans, Colorimetry instrumentation, Sweat chemistry, Wearable Electronic Devices, Biosensing Techniques instrumentation, Equipment Design
- Abstract
Sweat contains abundant physiological and metabolic data to evaluate an individual's physical health. Since the non-exercise sweat secretion rate is low, with an average value of 1-10 μl h
-1 cm-2 , sweat is generally collected during exercise for existing wearable sweat sensors. To expand their applications to include daily scenarios, these sensors developed for sports and fitness are challenged by the difficulty of collecting trace amounts of sweat. This study proposes a wearable patch inspired by the hierarchical structure of Sarracenia trichomes, allowing for the spontaneous and fast collection of a small amount of secreted sweat. The patch contains microfluidic channels featuring a 20 μm-wide rib structure, fully utilizing the capillary force, thereby eliminating the issue of sweat hysteresis. Furthermore, with only 0.5 μl of the sweat secreted at the collection site, it can converge on the detection medium located within the center reservoir. Volunteer verification demonstrated a twofold increase in sweat collection efficiency compared to traditional wearable patches. This patch serves as an efficient sweat-collection configuration, promising potential for diverse in situ sweat colorimetric analyses., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Zhinan Zhang reports financial support was provided by State Key Laboratory of Mechanical System and Vibration. Zhinan Zhang reports financial support was provided by the open project of National Research Center for Translational Medicine, Shanghai. Zhinan Zhang reports financial support was provided by High-end Foreign Experts Recruitment Plan. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)- Published
- 2024
- Full Text
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48. Pressure-induced generation of heterogeneous electrocatalytic metal hydride surfaces for sustainable hydrogen transfer.
- Author
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Luo L, Liu X, Zhao X, Zhang X, Peng HJ, Ye K, Jiang K, Jiang Q, Zeng J, Zheng T, and Xia C
- Abstract
Metal hydrides are crucial intermediates in numerous catalytic reactions. Intensive efforts have been dedicated to constructing molecular metal hydrides, where toxic precursors and delicate mediators are usually involved. Herein, we demonstrate a facile pressure-induced methodology to generate a cost-effective heterogeneous electrocatalytic metal hydride surface for sustainable hydrogen transfer. Taking carbon dioxide (CO
2 ) electroreduction as a model system and zinc (Zn), a well-known carbon monoxide (CO)-selective catalyst, as a model catalyst, we showcase a homogeneous-type hydrogen atom transfer process induced by heterogeneous hydride surfaces, enabling direct hydrogenation pathways traditionally considered "prohibited". Specifically, the maximal Faradaic efficiency for formate is enhanced by ~fivefold to 83% under ambient conditions. Experimental and theoretical analyses reveal that unlike the distal hydrogenation route for CO2 to CO over pristine Zn, the Zn hydride surface enables direct hydrogenation at the carbon site of CO2 to form formate. This work provides a promising material platform for sustainable synthesis., (© 2024. The Author(s).)- Published
- 2024
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49. Intelligent surgical planning for automatic reconstruction of orbital blowout fracture using a prior adversarial generative network.
- Author
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Xu J, Wei Y, Jiang S, Zhou H, Li Y, and Chen X
- Abstract
Orbital blowout fracture (OBF) is a disease that can result in herniation of orbital soft tissue, enophthalmos, and even severe visual dysfunction. Given the complex and diverse types of orbital wall fractures, reconstructing the orbital wall presents a significant challenge in OBF repair surgery. Accurate surgical planning is crucial in addressing this issue. However, there is currently a lack of efficient and precise surgical planning methods. Therefore, we propose an intelligent surgical planning method for automatic OBF reconstruction based on a prior adversarial generative network (GAN). Firstly, an automatic generation method of symmetric prior anatomical knowledge (SPAK) based on spatial transformation is proposed to guide the reconstruction of fractured orbital wall. Secondly, a reconstruction network based on SPAK-guided GAN is proposed to achieve accurate and automatic reconstruction of fractured orbital wall. Building upon this, a new surgical planning workflow based on the proposed reconstruction network and 3D Slicer software is developed to simplify the operational steps. Finally, the proposed surgical planning method is successfully applied in OBF repair surgery, verifying its reliability. Experimental results demonstrate that the proposed reconstruction network achieves relatively accurate automatic reconstruction of the orbital wall, with an average DSC of 92.35 ± 2.13% and a 95% Hausdorff distance of 0.59 ± 0.23 mm, markedly outperforming the compared state-of-the-art networks. Additionally, the proposed surgical planning workflow reduces the traditional planning time from an average of 25 min and 17.8 s to just 1 min and 35.1 s, greatly enhancing planning efficiency. In the future, the proposed surgical planning method will have good application prospects in OBF repair surgery., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)
- Published
- 2024
- Full Text
- View/download PDF
50. Ultrahigh electromechanical response from competing ferroic orders.
- Author
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Lin B, Ong KP, Yang T, Zeng Q, Hui HK, Ye Z, Sim C, Yen Z, Yang P, Dou Y, Li X, Gao X, Tan CKI, Lim ZS, Zeng S, Luo T, Xu J, Tong X, Li PWF, Ren M, Zeng K, Sun C, Ramakrishna S, Breese MBH, Boothroyd C, Lee C, Singh DJ, Lam YM, and Liu H
- Abstract
Materials with electromechanical coupling are essential for transducers and acoustic devices as reversible converters between mechanical and electrical energy
1-6 . High electromechanical responses are typically found in materials with strong structural instabilities, conventionally achieved by two strategies-morphotropic phase boundaries7 and nanoscale structural heterogeneity8 . Here we demonstrate a different strategy to accomplish ultrahigh electromechanical response by inducing extreme structural instability from competing antiferroelectric and ferroelectric orders. Guided by the phase diagram and theoretical calculations, we designed the coexistence of antiferroelectric orthorhombic and ferroelectric rhombohedral phases in sodium niobate thin films. These films show effective piezoelectric coefficients above 5,000 pm V-1 because of electric-field-induced antiferroelectric-ferroelectric phase transitions. Our results provide a general approach to design and exploit antiferroelectric materials for electromechanical devices., (© 2024. The Author(s).)- Published
- 2024
- Full Text
- View/download PDF
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