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The gait rehabilitation knee exoskeleton is an advanced rehabilitative assistive device designed to help patients with knee joint dysfunction regain normal gait through training and activity support. This paper introduces a design framework based on the process knowledge representation method to optimize the design and control efficiency of the knee exoskeleton. This framework integrates knowledge of design objects and processes, specifically including requirements, functions, principle work areas, and the representation and multi-dimensional dynamic mapping of the Behavior–Structure (RFPBS) matrix, achieving multi-dimensional dynamic mapping of the knee exoskeleton. This method incorporates biomechanical and physiological knowledge from the rehabilitation process to more effectively simulate and support gait movements during rehabilitation. Research results indicate that the knee rehabilitation exoskeleton design, based on the RFPBS process knowledge representation model, accomplishes multi-dimensional dynamic mapping, providing a scientific basis and effective support for the rehabilitation of patients with knee joint dysfunction. [ABSTRACT FROM AUTHOR]

Bidirectional associative memories (BAMs) have been extensively applied in auto and heteroassociative learning. However, the research on the hardware implementation of BAM neural networks is relatively few. Memristor, a nanoscale synaptic-like element, provides a new perspective for the circuit implementation of neural networks. In this work, we improve a threshold memristor bridge circuit (T-MBC) and design a novel memristive bidirectional associative memory (MBAM) network circuit on this basis. T-MBC is capable to achieve positive, negative, and zero synaptic weights without any switches, inverters, transistors, and current–voltage conversion processes. The validity of T-MBC is illustrated by PSPICE. MBAM has a simpler structure and gains excellent effects in flexibility, and reconfigurability. Besides, it is shown that MBAM can be trained to recall both disturbed binary images and incomplete/noisy grey-scale images robustly. Meanwhile, a more complex application of emotion classification based on MBAM is also accomplished. Experimental results verify the effectiveness of the MBAM neural network and demonstrate that the MBAM neural network has high recognition accuracy and strong noise immunity. [ABSTRACT FROM AUTHOR]

The memristor is a nano-size electrical device that is widely investigated in memory, logic circuits, and neuromorphic systems. This paper puts forward a general window function for Hewlett-Packard (HP) TiO 2 memristor model, which covers almost all typical window functions and resolves the boundary lock problem, the inflexible parameter problem, and the distorted pinched hysteresis loop problem. Several adjustable parameters are introduced in the proposed window function in order to make it more fle x ible and scalable. A comparison with some classic window functions is given. Meanwhile, the range of these parameters is deduced with the aim of finding suitable parameters to simulate memristor devices. This TiO 2 memristor model based on the novel window function is further applied to the spiking neural network and tested with the MNIST database of handwritten digits. The result demonstrates that the memristor-based neural network has higher recognition accuracy and better classification effect, indicating the availability of the entire scheme. [ABSTRACT FROM AUTHOR]

Efficient electro‐oxidation of formic acid, methanol, and ethanol is challenging owing to the multiple chemical reaction steps required to accomplish full oxidation to CO2. Herein, a ternary CoPtAu nanoparticle catalyst system is reported in which Co and Pt form an intermetallic L10‐structure and Au segregates on the surface to alloy with Pt. The L10‐structure stabilizes Co and significantly enhances the catalysis of the PtAu surface towards electro‐oxidation of ethanol, methanol, and formic acid, with mass activities of 1.55 A/mgPt, 1.49 A/mgPt, and 11.97 A/mgPt, respectively in 0.1 m HClO4. The L10‐CoPtAu catalyst is also stable, with negligible degradation in mass activities and no obvious Co/Pt/Au composition changes after 10 000 potential cycles. The in situ surface‐enhanced infrared absorption spectroscopy study indicates that the ternary catalyst activates the C−C bond more efficiently for ethanol oxidation. [ABSTRACT FROM AUTHOR]

Efficient electro‐oxidation of formic acid, methanol, and ethanol is challenging owing to the multiple chemical reaction steps required to accomplish full oxidation to CO2. Herein, a ternary CoPtAu nanoparticle catalyst system is reported in which Co and Pt form an intermetallic L10‐structure and Au segregates on the surface to alloy with Pt. The L10‐structure stabilizes Co and significantly enhances the catalysis of the PtAu surface towards electro‐oxidation of ethanol, methanol, and formic acid, with mass activities of 1.55 A/mgPt, 1.49 A/mgPt, and 11.97 A/mgPt, respectively in 0.1 m HClO4. The L10‐CoPtAu catalyst is also stable, with negligible degradation in mass activities and no obvious Co/Pt/Au composition changes after 10 000 potential cycles. The in situ surface‐enhanced infrared absorption spectroscopy study indicates that the ternary catalyst activates the C−C bond more efficiently for ethanol oxidation. [ABSTRACT FROM AUTHOR]

Co-based catalysts are highly active for synthesizing long-chain paraffins through Fischer–Tropsch synthesis. However, their exothermic reactions can cause overheating and catalyst deactivation. To address this, thermally conductive SiC-Al 2 O 3 pellets (HeatPath™) were coated with a Co/Re/Al 2 O 3 shell, significantly boosting the CO conversion rate and the yield of C 2–4 and C 5+ hydrocarbons over a wide range of temperatures by dissipating the reaction heat. The core@shell HeatPath@Co/Re/Al 2 O 3 catalyst demonstrated high productivity (up to 19.7 g CO g cat − 1 h−1), exceptional long-term stability over 660 h time-on-stream, with high-temperature operation up to 260 °C, a low CH 4 selectivity (7.1 %) and a chain growth probability (α) > 0.8. In contrast, the irreversible deactivation of a powder Co/Re/Al 2 O 3 catalyst started at 195 °C, resulting in >60 % CH 4 selectivity and ∼100 % CO conversion due to excessive local heat. The CO conversion rate on the core@shell catalyst could be further improved by increasing the H 2 /CO ratio and temperature, with commercially viable CH 4 selectivity. [Display omitted] • core@shell SiC-Al 2 O 3 @Co-Re showed high performance in Fischer-Tropsch synthesis. • core@shell catalyst improved CO conversion rate and yield of C5 + hydrocarbons. • Heat dissipation property of SiC-Al 2 O 3 pellets enhanced Fischer-Tropsch performance. • Low CH 4 and CO 2 selectivities over a wide temperature range. • High productivity (∼19.7 g CO g cat − 1 h−1) and good stability >660 h time-on-stream. [ABSTRACT FROM AUTHOR]

A quick method to directly determine the true stress–strain curve over a large strain range is proposed. The true stress–strain curve includes the post-necking strain, is directly measured via a special multi-camera digital image correlation (DIC) system. A tension test with the standard dog-bone shape specimens is used in the system. The cross-section area of the specimen throughout the test is measured by the DIC, as well as the entire field true strain. The true stress is calculated based on the measured cross-section area and the load. A dual-phase steel with a minimum 780 MPa tensile strength (DP780), as a typical advanced high-strength steel (AHSS), is used in the test to demonstrate the method and to validate the result. The true stress–strain curve including the post-necking data of DP780 is presented. The test result is validated with the theoretical calculation as well as the experimental method. Furthermore, the measured true stress–strain curve is approximated by the power law equation to identify the material constants. The methodology, experimental test, and the evaluated result are described in detail. [ABSTRACT FROM AUTHOR]

We report in this article a detailed study on how to stabilize a first-row transition metal (M) in an intermetallic L10-MPt alloy nanoparticle (NP) structure and how to surround the L10-MPt with an atomic layer of Pt to enhance the electrocatalysis of Pt for oxygen reduction reaction (ORR) in fuel cell operation conditions. Using 8 nm FePt NPs as an example, we demonstrate that Fe can be stabilized more efficiently in a core/shell structured L10-FePt/ Pt with a 5 À Pt shell. The presence of Fe in the alloy core induces the desired compression of the thin Pt shell, especially the two atomic layers of Pt shell, further improving the ORR catalysis. This leads to much enhanced Pt catalysis for ORR in 0.1 M HClO4 solution (at both room temperature and 60 °C) and in the membrane electrode assembly (MEA) at 80 °C. The L10-FePt/Pt catalyst has a mass activity of 0.7 A/mgPt from the half-cell ORR test and shows no obvious mass activity loss after 30 000 potential cycles between 0.6 and 0.95 V at 80 °C in the MEA, meeting the DOE 2020 target (<40% loss in mass activity). We are extending the concept and preparing other L10-MPt/Pt NPs, such as L10-CoPt/Pt NPs, with reduced NP size as a highly efficient ORR catalyst for automotive fuel cell applications. [ABSTRACT FROM AUTHOR]

Three dimensional digital image correlation (3D-DIC) has been widely used by industry to measure the 3D contour and whole-field displacement/strain. In this paper, a novel single color camera 3D-DIC setup, using a reflection-based pseudo-stereo system, is proposed. Compared to the conventional single camera pseudo-stereo system, which splits the CCD sensor into two halves to capture the stereo views, the proposed system achieves both views using the whole CCD chip and without reducing the spatial resolution. In addition, similarly to the conventional 3D-DIC system, the center of the two views stands in the center of the CCD chip, which minimizes the image distortion relative to the conventional pseudo-stereo system. The two overlapped views in the CCD are separated by the color domain, and the standard 3D-DIC algorithm can be utilized directly to perform the evaluation. The system’s principle and experimental setup are described in detail, and multiple tests are performed to validate the system. [ABSTRACT FROM AUTHOR]

Selective hydrogenation of cinnamaldehyde (CAL) to cinnamyl alcohol (COL) was conducted over a series of FeO x -doped Pt catalysts supported on a 15 wt% Al 2 O 3 @SBA-15 composite (15AS). It was found that the addition of FeO x to the catalyst greatly improved its performance. With an optimal Fe/Pt molar ratio of 0.25, the PtFe 0.25 /15AS catalyst reached a maximum reaction rate (defined as moles of converted CAL per gram of Pt per hour) of 13.93 mol g Pt −1 h −1 with 76.9% selectivity to COL. Additionally, the PtFe 0.25 /15AS catalyst afforded the highest TOF value (defined as moles of converted CAL per mole of Pt active sites per second) of 1.54 s −1 . X-ray photoelectron spectroscopy analyses and H 2 temperature-programmed reduction and CO diffuse-reflectance infrared Fourier-transformation spectroscopy studies reveal that there is strong interaction between Pt nanoparticles and Al 2 O 3 @SBA-15 composites and also between Pt and FeO x , resulting in Pt species with a positive charge being dominant in PtFe 0.25 /15AS catalysts. Therefore, Pt species with positive charges, together with FeO x species, are beneficial for preferential adsorption and activation of carbonyl bonds of CAL, so that the activity and selectivity to COL were improved by PtFe x /15AS catalysts ( x represents the Fe/Pt molar ratio). [ABSTRACT FROM AUTHOR]

Three Dimensional digital image correlation(3D-DIC) has been widely used by industry, especially for strain measurement. The traditional 3D-DIC system can accurately obtain the whole-field 3D deformation. However, the conventional 3D-DIC system can only acquire the displacement field on a single surface, thus lacking information in the depth direction. Therefore, the strain in the thickness direction cannot be measured. In recent years, multiple camera DIC (multi-camera DIC) systems have become a new research topic, which provides much more measurement possibility compared to the conventional 3D-DIC system. In this paper, a multi-camera DIC system used to measure the whole-field thickness strain is introduced in detail. Four cameras are used in the system. two of them are placed at the front side of the object, and the other two cameras are placed at the back side. Each pair of cameras constitutes a sub stereo-vision system and measures the whole-field 3D deformation on one side of the object. A special calibration plate is used to calibrate the system, and the information from these two subsystems is linked by the calibration result. Whole-field thickness strain can be measured using the information obtained from both sides of the object. Additionally, the major and minor strain on the object surface are obtained simultaneously, and a whole-field quasi 3D strain history is acquired. The theory derivation for the system, experimental process, and application of determining the thinning strain limit based on the obtained whole-field thickness strain history are introduced in detail. [ABSTRACT FROM AUTHOR]

The short-side-chain (SSC) perfluorosulfonic acid (PFSA) membranes are important candidates as membrane electrolytes applied for high temperature or low relative humidity (RH) proton exchange membrane fuel cells. In this paper, the fuel cell performance, proton conductivity, proton mobility, and water vapor absorption of SSC PFSA electrolytes and the reinforced SSC PFSA/PTFE composite membrane are investigated with respect to temperature. The pristine SSC PFSA membrane and reinforced SSC composite membrane show better fuel cell performance and proton conductivity, especially at high temperature and low relative humidity conditions, compared to the long-side-chain (LSC) Nafion membrane. Under the same condition, the proton mobility of SSC PFSA membranes is lower than that of the LSC PFSA membrane. The water vapor uptake values for Nafion 211 membrane, pristine SSC PFSA membrane and SSC PFSA/PTFE composite membrane are 9.62, 11.13, and 11.53 respectively at 40 °C and they increase to 9.89, 12.55 and 13.09 respectively at 120 °C. The high water content of SSC PFSA membrane makes it maintain high performance even at elevated temperatures. [ABSTRACT FROM AUTHOR]

Comparative genomic studies suggest that a huge number of genes that show the strongest evidence for positive selection in human are testis- or sperm-specific genes, which are possibly due to germline selection. We propose a novel selection model in which the germlines of heterozygous males in a monogamous population are under natural selection. Under this model, we study the dynamics of a strongly selected substitution in the male germline and its hitch-hiking effect on the preexisting linked neutral polymorphism. We show that the expected heterozygosity at the neural locus is reduced by , where c is the recombination rate between selected and neutral locus, s is selective coefficient of advantageous allele, and N is diploid effective population size. [ABSTRACT FROM AUTHOR]

Abstract: Impregnating hygroscopic nanoparticles, typically silica in Nafion membrane has received intense interest in high-temperature PEMFCs application due to increased water retention ability, proton conductivity and mechanical stability. However, typical Nafion/silica membranes may suffer from potential durability degradation because of the instability of inorganic–organic electrostatic interface under humidifying conditions. Here, we investigate microstructural evolutions of this membrane and the subsequent performance. Aggregation and dissolving of silica nanoparticles and membrane fractures are observed under humidifying and RH cycling tests, thus leading to a significant decay of proton conductivities from ∼0.095 S cm−1 to ∼0.055 S cm−1 after 720 h of RH cycles. Simultaneously, H2 crossover soars to nearly 40 times larger than the initial. Inorganic–organic interfaces are recognized to be crucial in the stability and performance of this type of composite membrane. The insight into the degradation process will provide meaningful reference for optimizing composite membranes and designing competent candidates for high-temperature PEMFCs operation. [Copyright &y& Elsevier]

Teasing apart the effects of selection and demography on genetic polymorphism remains one of the major challenges in the analysis of population genomic data. The traditional approach has been to assume that demography would leave a genome-wide signature, whereas the effect of selection would be local. In the light of recent genomic surveys of sequence polymorphism, several authors have argued that this approach is questionable based on the evidence of the pervasive role of positive selection and that new approaches are needed. In the first part of this review, we give a few empirical and theoretical examples illustrating the difficulty in teasing apart the effects of selection and demography on genomic polymorphism patterns. In the second part, we review recent efforts to detect recent positive selection. Most available methods still rely on an a priori classification of sites in the genome but there are many promising new approaches. These new methods make use of the latest developments in statistics, explore aspects of the data that had been neglected hitherto or take advantage of the emerging population genomic data. A current and promising approach is based on first estimating demographic and genetic parameters, using, e.g., a likelihood or approximate Bayesian computation framework, focusing on extreme outlier regions, and then using an independent method to confirm these. Finally, especially for species where evidence of natural selection has been limited, more experimental and versatile approaches that contrast populations under varied environmental constraints might be more successful compared with species-wide genome scans in search of specific signatures. [ABSTRACT FROM AUTHOR]

Highly ordered and periodic mesoporous Nafion membranes with controlled structural symmetries including 2D hexagonal, 3D face-centered, 3D cubic-bicontinuous and 3D body-centered have been successfully synthesized by a novel colloidal silica mediated self-assembly method with high proton conductivity particularly under conditions of low humidity. [ABSTRACT FROM AUTHOR]

As mentioned in Part 1, for product iterative design, the digital simulation method, as the product performance analysis method, has the problems of time cost and computing resources. To address this issue, a product performance rapid simulation approach driven by digital twin (DT) data for variable product structures in Part 1 was proposed, which could replace the digital simulation method. Meanwhile, for performance analysis under variable operating conditions during the product design and operation phase, digital simulation also has the above problems. Therefore, based on the method for variable product structures proposed in Part 1, a product performance rapid simulation approach driven by DT data for variable operating conditions is proposed in this paper. Firstly, the framework for variable operating conditions is designed based on the makeTwin reference architecture, including twin source data acquisition for the product under different operating conditions, twin data-driven product performance rapid simulation model (RSM) construction for variable operating conditions, and rapid evaluation of product critical performance based on RSM. Then, the implementation of the framework is introduced in detail. At last, a case study for critical loosening load evaluation of bolted joint is carried out. The result indicates that the proposed method is feasible, as well as costs shorter simulation time than the traditional digital simulation method. [ABSTRACT FROM AUTHOR]

The vibration response generated by the operation of a metro system has a profound impact on the physical and mental well-being of urban residents. Vibration control is essential to effectively isolate the multi-band vibration response and structure-borne noise of buildings. Laminated rubber bearings between the foundation and the superstructures serve as a common, cost-effective solution for the seismic isolation of structures and have great potential to be used for metro-induced vibration mitigation. In this study, two types of full-scale laminated rubber bearings (i.e., linear natural rubber bearing and lead rubber bearing) were tested under various compressive stresses, ranging from 5 MPa to 15 MPa, to examine the static and dynamic characteristics of the bearings, including vertical hysteresis curves, vertical static stiffness, time history response, and frequency spectrum. Then, the numerical simulation of a base-isolated building structure equipped with laminated rubber bearings was conducted to evaluate the vertical vibration isolation performance and structure-borne noise isolation capability. It was demonstrated that the laminated rubber bearings have stable vertical bearing capacities and performance in isolating vertical vibrations. • Full-scale vertical static and dynamic tests of laminated rubber bearings under compressive stresses are conducted. • The laminated rubber bearings exhibit consistently stable performance in isolating vertical vibrations. • A numerical analysis confirms excellent performance in isolating both metro-induced vibrations and structure-borne noise. [ABSTRACT FROM AUTHOR]

The tensile behaviour of engineered cementitious composites (ECC) is highly dependent on their microstructure characteristics. To date, the strain-hardening behaviour of printed ECC in relation to its microstructure is not yet fully understood. This study presents a systematic investigation on the macroscopic mechanical properties of normal and printed ECC with various polyethylene (PE) fibre lengths (6 and 12 mm) in relation to their microstructural features in terms of pore structure characteristics, fibre orientation and fibre dispersion through a series of mechanical tests and X-ray computed tomography (CT) and backscattered electron (BSE) image acquisition, processing and analysis. Results indicate that it is desirable to use block specimens for mould-casting fabrication as contrast to printed ECC samples. The printed ECC containing 1.5 vol% 6 mm and 0.5 vol% 12 mm PE fibres by extrusion-based 3D printing exhibits unique tensile ductility of over 5% and average crack width of less than 100 μm. Regarding pore structure, normal ECC has a higher probability of large pores (over 1 mm3) than printed ECC, which would increase the risk of damage localization and lead to a significant variation in tensile properties. Besides, normal ECC with thickness of 30 mm and printed ECC possess a similar fist cracking strength as indicated by similar pore size and fracture toughness. Compared to normal ECC, printed ECC has a more uniform dispersion of PE fibres, the orientation of which is more perpendicular to the loading direction, resulting in a higher average tensile strength and strain capacity than normal ECC. [ABSTRACT FROM AUTHOR]

[Display omitted] • Zn x Ti y O z with well-defined surface were synthesized by liquid-phase grafting using (1 0 1) or (0 0 1) facet dominant anatase. • Site requirements of acetone to isobutene reaction at molecular level were studied by faceted mixed metal oxides. • The bridging OHs with rapid proton transfer efficiently stabilize a transition state in the acetone to isobutene conversion. Liquid-phase chemical grafting method was used to graft Zn onto TiO 2 with preferentially exposed (1 0 1) or (0 0 1) facet. The obtained Zn x Ti y O z materials were characterized using various techniques (e.g., XRD, Raman, DRIFTS etc.) and evaluated for the acetone-to-isobutene reaction. It was found that over TiO 2 (0 0 1), both terminal and bridging hydroxyls were readily titrated by Zn deposition, whereas a substantial amount of bridging hydroxyls on TiO 2 (1 0 1) remained. Although dominant Zn-O-terminated surface was obtained on two Zn x Ti y O z samples, bridging hydroxyls with high H-D exchange reactivity were observed on Zn x Ti y O z (1 0 1) compared with Zn x Ti y O z (0 0 1). The bridging hydroxyls showing rapid proton transfer efficiently stabilizes a transition state of diacetone alcohol intramolecular rearrangement for isobutene production as opposed to the diacetone alcohol dehydration. [ABSTRACT FROM AUTHOR]

Abstract: The effects of the nature of the solvent on the morphology of perfluorosulfonate ionomers in dispersions and the microstructures of the corresponding formed membranes are investigated. The subsequent electrochemical performances of the formed proton exchange membranes are also studied in detail. It is found that the diameters of the Nafion molecular aggregates in variable solutions decrease with an increase in the solvent dielectric constant (ε) and a decrease in the gap of the solubility parameters (δ) between the resin and the solvent. The micromorphology of Nafion is further examined by means of transmission electron microscopy, small-angle X-ray scattering, and X-ray diffraction. It is found that the membrane cast from a Nafion-2-propanol/water dispersion with ε value of 42.38 and a δ gap of 0.01 (cal cm−3)1/2 has a better ion cluster arrangement, smaller ion cluster size (approximately 13 Å), and higher crystallinity (16.7%) than the other samples. The electrochemical properties of the formed membranes are further investigated as a function of temperature, relative humidity, and the solubility parameter of the applied solvents. The results demonstrate that the electrochemical performance is strongly influenced by the solvent-induced microstructure of the backbone and the ionic clusters in the perfluorosulfonic acid membrane. [Copyright &y& Elsevier]

Direct deoxygenation of long‐chain fatty acids can produce both saturated alkanes (CnH2n+2) and unsaturated olefins (CnH2n). However, the selectivity for the production of olefins via the decarbonylation route is relatively low because of the more favorable decarboxylation pathway. We present an atomically ordered intermetallic PtZn alloy on carbon catalyst (PtZn/C) with a record‐high total selectivity (97 %) for undecane (C11H24) and undecene (C11H22) in the deoxygenation of lauric acid (C12H24O2). Interestingly, the selectivity for C11H22 is as high as 67.0 % on PtZn/C, which is significantly higher than that of 27.5 % obtained on the Pt/C counterpart under the same reaction conditions. Characterization and theoretical calculation results reveal that the intermetallic PtZn alloy not only inhibits the decarboxylation route by increasing the energy barrier of −COO* cleavage, but also facilitates the decarbonylation route by decreasing CO desorption energy, and therefore the major product is switched from alkanes to olefins. [ABSTRACT FROM AUTHOR]

Direct deoxygenation of long‐chain fatty acids can produce both saturated alkanes (CnH2n+2) and unsaturated olefins (CnH2n). However, the selectivity for the production of olefins via the decarbonylation route is relatively low because of the more favorable decarboxylation pathway. We present an atomically ordered intermetallic PtZn alloy on carbon catalyst (PtZn/C) with a record‐high total selectivity (97 %) for undecane (C11H24) and undecene (C11H22) in the deoxygenation of lauric acid (C12H24O2). Interestingly, the selectivity for C11H22 is as high as 67.0 % on PtZn/C, which is significantly higher than that of 27.5 % obtained on the Pt/C counterpart under the same reaction conditions. Characterization and theoretical calculation results reveal that the intermetallic PtZn alloy not only inhibits the decarboxylation route by increasing the energy barrier of −COO* cleavage, but also facilitates the decarbonylation route by decreasing CO desorption energy, and therefore the major product is switched from alkanes to olefins. [ABSTRACT FROM AUTHOR]

Abstract: In this work, we developed a novel composite membrane by anchoring perfluorosulfonic acid into the hydrophilic poly(lactic-co-glycolic acid) (PLGA) nanofibrous network which was synthesized by electrospinning method. It was clear that the PLGA/Nafion composite membranes possessed high Nafion loading, excellent dimensional stability and proton transport capacity. When the humidity of the membrane changed from soaking in water to 25 RH% at 90 °C, the PLGA fiber network effectively controlled the swelling of Nafion resin and reduced the humidity-generated shrinkage stress from 2.2 MPa (Nafion211 membranes) to 0.5 MPa (PLGA/Nafion composite membranes). The proportion of humidity-induced stress to the yield strength was also reduced to 4.4%, in comparison to 21.2% of that of Nafion211 membrane. The area proton conductivity of the PLGA/Nafion composite membrane achieved 48.2 S cm−2, compared with 36.0 S cm−2 of Nafion211 membranes in the same condition. The excellent proton transport capacity greatly improved the performance of fuel cell assembled with PLGA/Nafion composite membranes and effectively reduced the dynamic response time from 22 s (Nafion211 membranes) to 7 s (PLGA/Nafion composite membranes). [Copyright &y& Elsevier]

Background and purpose: This study was undertaken to screen the circular RNAs (circRNAs) influencing matrix metalloproteinase 9 (MMP9) through the competing endogenous RNA (ceRNA) network and evaluate the prognostic value of these circRNAs for acute ischemic stroke. Methods: A total of 220 ischemic stroke patients and 62 healthy subjects were included in this study. RNA was isolated from blood collected in PAXgene tubes. Illumina sequencing, quantitative real‐time polymerase chain reaction (qRT‐PCR) validation, and luciferase reporter assay were explored to construct and verify the existence of a circRNA–microRNA (miRNA)–matrix metalloproteinase–9 (MMP9) network. The 215 ischemic stroke patients were recruited in a prognostic cohort. They were prospectively followed up for 3 months after stroke onset, and a poor functional outcome was defined as a major disability or death. Results: After Illumina sequencing, six circRNAs were predicted to bind miRNAs and then regulate MMP9 messenger RNA (mRNA). qRT‐PCR showed that only circSKA3 was significantly increased in ischemic stroke patients compared to healthy controls and positively associated with MMP9 mRNA expression. Luciferase reporter assay further verified a direct interaction between circSKA3, MMP9, and hsa‐miR‐6796‐5p. Patients in the top tertile of circSKA3 had a 2.672‐fold (p < 0.05) risk of poor functional outcome, compared with those in the bottom tertile (p for trend = 0.016). The outcome was predicted by circSKA3 with area under the receiver operating characteristic curve at 0.614 (p = 0.004). Conclusions: circSKA3 functioned as a ceRNA for hsa‐miR‐6796‐5p to aggravate the progression of ischemic stroke via targeting MMP9. Baseline circSKA3 was positively associated with poor outcomes of ischemic stroke. circSKA3 may be a potential biomarker or therapeutic target in ischemic stroke. [ABSTRACT FROM AUTHOR]

• The new digital shearography meets the requirements of high standards, making it suitable for dynamic tests while providing high-quality phase maps. • Both shearing direction and amount can be controlled quantitatively and accurately. • Phase maps can be evaluated with a single exposure. • High light efficiency and accurate phase demodulation lead to high-quality phase maps. Digital shearography (DS), a laser-based optical interferometric method, is widely employed for measuring the first-order derivative of an object's surface deformation. Unlike digital holography, DS integrates self-reference optics, enhancing resistance to environmental disturbance and improving detection sensitivity, making it ideal for non-destructive testing (NDT). DS finds applications in diverse fields such as material inspection, fluid property research, medical diagnostics, cultural heritage restoration, and military defense. The conventional temporal phase-shift (TPS) method encounters limitations in dynamic tests, leading to the introduction of the spatial phase-shift (SPS) method. However, SPS is restricted by aperture size, impacting the phase map quality. The spatial light modulator (SLM) introduces a novel approach to DS system development, enabling quantitative shearing adjustments through precise SLM control. Existing DS systems using traditional phase-shift technology rely on interferometers and struggle to achieve high-quality phase maps with a single exposure. The proposed high-performance DS, leveraging both SLM and a micro-polarizer camera, overcomes this limitation, facilitates single-exposure phase map evaluation with the polarization phase-shift technique, and eliminates the need for a tiny aperture, enhancing light beam utilization and phase map quality. [ABSTRACT FROM AUTHOR]

• The synergistic combination of microwave technology and mixed-linker strategy in COF synthesis. • This synthetic approach enables the facile and rapid synthesis of isoreticular mixed-linker COFs within an hour under air. • This approach enables fine-tuning of the physicochemical properties of COFs and thus tailors the adsorption performance towards iodine vapor. • The obtained mixed-linker COF manifested exceptional iodine adsorption capability compared to most existing COF adsorbents. The use of covalent organic frameworks (COFs) for hazardous radioiodine capture has been highly sought after recently. However, the synthesis of high-performance COF adsorbents while circumventing the limitations of traditional solvothermal methods remains largely unexplored. Herein, we for the first time combine microwave-assisted synthesis and mixed-linker strategy to fabricate multivariate COF adsorbents (X% OMe-TFB-BD COFs, X% = 0, 33, 50, 67, and 100 mol%) with varying ratios of benzidine (BD) and 3,3′-dimethoxylbenzidine (BD-OMe) linkers in a rapid and facile manner. Adjusting the BD-OMe/BD mole ratios has led to distinct variations in density, crystallinity, porosity, morphology, and thermal/chemical stability of the resultant COFs, which empowered fine-tuning of the adsorption performance towards static iodine vapor. Remarkably, the 50 % OMe-TFB-BD COF exhibited an ultrahigh iodine adsorption capability of 8.2 g g−1, surpassing those of single-component COFs, mixed-linker COFs with other methoxy content, physically blended mixtures, and most existing COF adsorbents. Moreover, 50 % OMe-TFB-BD COF was recyclable seven times without obvious loss in its adsorption capacity. This work underscores the substantial potential of microwave-assisted mixed-linker strategy as a viable approach for developing multivariate COFs with shortened reaction times, precisely tailored pore environment, and tunable sorption properties, which are of considerable promise for environmental remediation and other niche applications. Enormous efforts have been dedicated to exploring the application of covalent organic frameworks (COFs) in capturing hazardous radioiodine. However, the synthesis of efficient COF adsorbents while overcoming the limitations of traditional solvothermal methods remains largely unexplored. In this study, we present a facile microwave-assisted mixed-linker strategy to afford multivariate COF adsorbents, which exhibited tunable and ultrahigh adsorption performance towards radioiodine vapor. This novel strategy paves a facile, rapid, and engery-efficent avenue to access multivariate COFs tailored for environmental remediation. [ABSTRACT FROM AUTHOR]

Three-dimensional (3D) isolation bearings are effective means to reduce the adverse effects of metro vibrations on structures. The current research focuses on the relationship between the vertical stiffness and metro vibration isolation performance of bearings, but neglects the vibration filtering effect resulting from the inherent resonance and material damping effect of them. In this study, a novel 3D isolation bearing was proposed, composed of spring bearings (SBs) and laminated nature rubber bearings (LNR) vertically in series (denoted as 3DSL), and not only its vertical stiffness but also vibration filtering effect on metro-induced vibration isolation performance were fully studied. The design principle and vibration isolation mechanism of the 3DSL were described, followed by the design and test of three specimens. After that, a case study was conducted to investigate the influence of the 3DSL's filtering effect on metro vibration isolation. The results indicated that the 3DSL exhibited high vertical loading capacity and low vertical stiffness. Furthermore, it was found that the vibration amplitude was slightly amplified in the low-frequency range (1–50 Hz), while significantly reduced in the high-frequency range (50–200 Hz) due to the vibration filtering effect of the 3DSL. Altogether, these results demonstrated that the excellent metro vibration isolation performance of the 3DSL was attributed to the low vertical stiffness and vibration filtering effect. It is recommended to consider both the reduction of vertical stiffness and vibration filtering effect of 3D isolation bearings when designing isolation systems for metro vibrations. • A 3D isolation bearing (3DSL) was proposed for metro vibration isolation. • Mechanical properties and vibration filtering effect of 3DSL in metro vibrations were studied. • 3DSL exhibited high vertical loading capacity and low vertical stiffness. • 3DSL amplified low-frequency (1–50 Hz) but significantly reduced high-frequency (50–200 Hz) metro vibrations. • It is recommended to consider both the reduction of vertical stiffness and vibration filtering effect of 3D isolation bearings when designing isolation systems for metro vibrations. [ABSTRACT FROM AUTHOR]

Herein, we describe a AuPd catalyst for selective and solventless conversion of ethyl levulinate (EL) and amines to pyrrolidones under ambient pressure. The optimized Au66Pd34 nanoparticle catalyst was stable and reusable over 10 runs. AuPd catalysis was extended to reductive amination of levulinic acid and 4-acetylbutyric acid, providing a green chemistry approach under milder conditions not only to pyrrolidones, but also to piperidines, both of which are important scaffolds in designing polymers, natural products and pharmaceuticals. [ABSTRACT FROM AUTHOR]

We report a general chemical approach to synthesize strongly ferromagnetic rare‐earth metal (REM) based SmCo and SmFeN nanoparticles (NPs) with ultra‐large coercivity. The synthesis started with the preparation of hexagonal CoO+Sm2O3 (denoted as SmCo‐O) multipods via decomposition of Sm(acac)3 and Co(acac)3 in oleylamine. These multipods were further reduced with Ca at 850 °C to form SmCo5 NPs with sizes tunable from 50 to 200 nm. The 200 nm SmCo5 NPs were dispersed in ethanol, and magnetically aligned in polyethylene glycol (PEG) matrix, yielding a PEG‐SmCo5 NP composite with the room temperature coercivity (Hc) of 49.2 kOe, the largest Hc among all ferromagnetic NPs ever reported, and saturated magnetic moment (Ms) of 88.7 emu g−1, the highest value reported for SmCo5 NPs. The method was extended to synthesize other ferromagnetic NPs of Sm2Co17, and, for the first time, of Sm2Fe17N3 NPs with Hc over 15 kOe and Ms reaching 127.9 emu g−1. These REM based NPs are important magnetic building blocks for fabrication of high‐performance permanent magnets, flexible magnets, and printable magnetic inks for energy and sensing applications. [ABSTRACT FROM AUTHOR]

We report a general chemical approach to synthesize strongly ferromagnetic rare‐earth metal (REM) based SmCo and SmFeN nanoparticles (NPs) with ultra‐large coercivity. The synthesis started with the preparation of hexagonal CoO+Sm2O3 (denoted as SmCo‐O) multipods via decomposition of Sm(acac)3 and Co(acac)3 in oleylamine. These multipods were further reduced with Ca at 850 °C to form SmCo5 NPs with sizes tunable from 50 to 200 nm. The 200 nm SmCo5 NPs were dispersed in ethanol, and magnetically aligned in polyethylene glycol (PEG) matrix, yielding a PEG‐SmCo5 NP composite with the room temperature coercivity (Hc) of 49.2 kOe, the largest Hc among all ferromagnetic NPs ever reported, and saturated magnetic moment (Ms) of 88.7 emu g−1, the highest value reported for SmCo5 NPs. The method was extended to synthesize other ferromagnetic NPs of Sm2Co17, and, for the first time, of Sm2Fe17N3 NPs with Hc over 15 kOe and Ms reaching 127.9 emu g−1. These REM based NPs are important magnetic building blocks for fabrication of high‐performance permanent magnets, flexible magnets, and printable magnetic inks for energy and sensing applications. A new chemical process is developed to prepare strongly ferromagnetic SmCo5 nanoparticles (NPs) via controlled reduction of SmCo‐O multipods. The 200 nm SmCo5 NPs embedded in polyethylene glycol are aligned magnetically and show the room temperature coercivity of 49.2 kOe. The synthetic method has also been extended to prepare ferromagnetic Sm2Co17 and Sm2Fe17N3 NPs. [ABSTRACT FROM AUTHOR]

We report a facile method for assembly of a monolayer array of nitrogen-doped graphene (NG) and nanoparticles (NPs) and the subsequent transfer of two layers onto a solid substrate (S). Using 3 nm NiPd NPs as an example, we demonstrate that NiPd-NG-Si (Si=silicon wafer) can function as a catalyst and show maximum NiPd catalysis for the hydrolysis of ammonia borane (H3NBH3, AB) with a turnover frequency (TOF) of 4896.8 h−1 and an activation energy ( Ea) of 18.8 kJ mol−1. The NiPd-NG-S catalyst is also highly active for catalyzing the transfer hydrogenation from AB to nitro compounds, leading to the green synthesis of quinazolines in water. Our assembly method can be extended to other graphene and NP catalyst materials, providing a new 2D NP catalyst platform for catalyzing multiple reactions in one pot with maximum efficiency. [ABSTRACT FROM AUTHOR]

We report a facile method for assembly of a monolayer array of nitrogen-doped graphene (NG) and nanoparticles (NPs) and the subsequent transfer of two layers onto a solid substrate (S). Using 3 nm NiPd NPs as an example, we demonstrate that NiPd-NG-Si (Si=silicon wafer) can function as a catalyst and show maximum NiPd catalysis for the hydrolysis of ammonia borane (H3NBH3, AB) with a turnover frequency (TOF) of 4896.8 h−1 and an activation energy ( Ea) of 18.8 kJ mol−1. The NiPd-NG-S catalyst is also highly active for catalyzing the transfer hydrogenation from AB to nitro compounds, leading to the green synthesis of quinazolines in water. Our assembly method can be extended to other graphene and NP catalyst materials, providing a new 2D NP catalyst platform for catalyzing multiple reactions in one pot with maximum efficiency. [ABSTRACT FROM AUTHOR]

A novel calibration method for phase-to-height (PTH) relationship in fringe projection profilometry (FPP) was proposed in this work. This proposed method can be applied to an FPP system of which the camera, projector and reference plane are positioned arbitrarily. First, a black-white pattern and four phase-shifted sinusoidal patterns are generated using a computer and projected onto the reference plane (o w -x w -y w coordinate plane) while being moved along its normal direction to several known positions. The camera records the projected fringe patterns on the reference plane at every position. Based on the projection principles of the camera and projector, unified phase values in this process were extracted enabling the PTH relationship to be determined easily. This makes the subtraction of a reference phase, as used in traditional FPP, is no longer necessary. Second, distorted fringe patterns reflected by target object are captured, and height values are calculated based on the obtained PTH relationship. Finally, by calibrating the intrinsic and extrinsic parameters of the camera, the 3D coordinates (x w ,y w ,z w ) of object surface can be determined accordingly. The proposed method was verified by experiments, which demonstrate the validity and accuracy of the proposed method. [ABSTRACT FROM AUTHOR]

We synthesize a new type of hybrid Pd/WO2.72 structure with 5 nm Pd nanoparticles (NPs) anchored on 50 × 5 nm WO2.72 nanorods. The strong Pd/WO2.72 coupling results in the lattice expansion of Pd from 0.23 to 0.27 nm and the decrease of Pd surface electron density. As a result, the Pd/WO2.72 shows much enhanced catalysis toward electrochemical oxidation of formic acid in 0.1 M HClO4; it has a mass activity of ~1600 mA/mgPd in a broad potential range of 0.4-0.85 V (vs RHE) and shows no obvious activity loss after a 12 h chronoamperometry test at 0.4 V. Our work demonstrates an important strategy to enhance Pd NP catalyst efficiency for energy conversion reactions. [ABSTRACT FROM AUTHOR]

Metal organic-framework MIL-101 and inorganic mesoporous composites Al 2 O 3 @SBA-15 supported Pt catalysts, Pt/MIL-101 and Pt/Al 2 O 3 @SBA-15 catalysts, were prepared and characterized by means of X-ray diffraction (XRD), N 2 adsorption–desorption, scanning electron microscopy (SEM), transmission electron microscopy (TEM), CO chemisorption and thermo-gravimetric (TG) analysis. Pt nanoparticles were highly dispersed on both supports. In liquid-phase hydrogenation of nitrobenzene, benzaldehyde and their derivatives, the Pt/MIL-101 catalyst was superior to the Pt/Al 2 O 3 @SBA-15 catalyst in water. For liquid-phase hydrogenation of nitrobenzene with the Pt/MIL-101 catalyst, owing to high solubility of nitrobenzene in ethanol, the reaction in ethanol went much faster than that in water, furnishing a turnover frequency (TOF) in ethanol up to 18,053 h −1 , almost triple of that obtained in water under similar conditions. The highest TOF of 25,438 h −1 was obtained in ethanol for hydrogenation of 3-chloro-nitrobenzene with the Pt/MIL-101 catalyst. As for hydrogenation of benzaldehyde series, 2-fluoro-benzaldehyde and 3-fluoro-benzaldehyde gave the highest TOFs of 5146 h −1 and 3165 h −1 in water with the Pt/MIL-101 and Pt/Al 2 O 3 @SBA-15 catalysts, respectively. We deduce that surface property of MIL-101 with high hydrophobicity is helpful to enrich reactants around the Pt/MIL-101 catalyst in water, where nitrobenzene or benzaldehyde and its derivatives have a limited solubility, so that high catalytic performance was achieved with the Pt/MIL-101 catalyst in water. Of particular note is that the Pt/MIL-101 catalyst can be reused at least four times without loss in activity or selectivity. [ABSTRACT FROM AUTHOR]

Digital shearography (DS) is a noncontact, whole-field, and laser-based optical interferometric method. It is a valuable tool in the field of nondestructive testing (NDT) and received considerable acceptance in the automotive and aerospace industries. Conventional DS only detects the flaws in one or two shearing/sensitive directions, which leads to the missed inspection and leaves quite a lot of suspected defects underdefined. A trishearing DS for NDT is proposed to solve the mentioned issue. The presented shearography is designed based on a multiplexed Mach–Zehnder interferometer embedded with the spatial phase shift technique. It measures the defects in three sensitive directions simultaneously and has balanced optical paths with high light efficiency. Moreover, the measurement sensitivity of each direction can be adjusted during the test, without affecting the carrier frequencies, so it meets various needs for NDT applications. The principle and the experimental validation of the proposed system are introduced in detail. [ABSTRACT FROM AUTHOR]

Abstract: Five transition-metal coordination polymers, namely, [Zn7Cl6(oba)4] n (1), [Cd7Cl6(oba)4] n (2), [Zn(oba)(H2O)] n (3), [Ag2(oba)] n (4) and [Co(oba)(H2O)2] n (5) (H2oba=4,4′-oxydibenzoic acid), have been achieved under hydrothermal conditions and structurally characterized by IR, elemental analyses, X-ray single-crystal diffraction and TGA. The X-ray single-crystal diffraction reveals that compounds 1 and 2 are isomorphism, featuring pillared-layer 3D motifs, in which the 2D inorganic layers (Zn6Cl7) n (or (Cd6Cl7) n ) are connected by oba2− pillars. Compound 3 exhibits 1D stair-like chain and extends to a 3D network by two different interchain O–H–O hydrogen bonding interactions while compound 4 features wave chains and stretches to 2D layer by interchain Ag–O weak contacts. Compound 5 shows 2D network in which Co-chains are pillared by oba2− ligand and then forms a 3D network by four different O–H–O hydrogen bonding interactions. Furthermore, 1–4 exhibit luminescent properties at a solid state and 5 shows antiferromagnetic behavior. [Copyright &y& Elsevier]

Abstract: Two new transition metal coordination complexes, {[MnO(nda)](H2dmt)(H2O)} n (1), [Ag5(nda)2.5(dmt)] n (2), (H2nda=naphthalene-1,4-dicarboxylic acid, dmt=2,4-diamine-6-methyl-1,3,5-triazine) have been hydrothermally synthesized by the reactions of H2nda and dmt with the homologous MnCl2·4H2O and AgNO3, respectively, and characterized by single-crystal X-ray diffraction, IR spectra, elemental analysis, thermogravimetric analysis (TGA). The compound 1 exhibits a 3D network comprising 1D metal chain {MnO(CO2)2} n connected by the ligand nda2−, featuring a four-connected uninodal diamond -like topology. In compound 2, it is firstly observed that decanuclear silver units as secondary building units to construct 3D network by the ligands dmt and nda2−, with a rare 2-nodal (3,8)-connected tfz-d topology ({43}2{46.618.84}). The interactions within each Mn(II)—Mn(II) pair of compound 1 are antiferromagnetic (g=2.07, J=−1.42(1)cm−1, zj′=−0.73(2) cm−1). In addition, compound 2 exhibits photoluminescent property at about 472nm (λ ex=394nm). [Copyright &y& Elsevier]

Electrochemical nitrogen reduction reaction (ENRR) is a mild and environmentally friendly process that can be potentially complementary to the traditional Haber-Bosch process. Development of high-performance ENRR catalysts and understanding of the activity origin of the catalyst are essential for the practical application of ENRR process. Herein, we report the size-dependent ENRR activity of monodisperse Au nanoparticles (NPs) sized ranging from 4 nm to 10 nm. 8 nm Au NPs is found to be an excellent ENRR catalyst with an ammonia production rate and Faradic efficiency of 17.49 μg h−1 mg−1 Au and 5.79%, respectively. The high ENRR performance of 8 nm Au NP is rationalized with DFT studies, which indicate that an optimal proportion of the surface step sites is key to suppressing hydrogen evolution reaction and improving the catalytic activity towards ENRR. The study herein may provide guidelines for tailoring the ENRR catalysis on nanostructured metal catalysts. Image 1 • Monodisperse Au NP is synthesized and used for ENRR. • Au NP with a diameter of ∼8 nm shows highest ENRR activity. • The 8 nm Au has a balanced fraction of corner site and edge site. [ABSTRACT FROM AUTHOR]