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The initial aim of this paper is to dramatically improve the post-treatment stage of biodiesel production, which converts problematic glycerol to solketal (SK), by introduction of an eco-efficient integrated reactive and dividing wall distillation process. To overcome the chemical equilibrium limitations and the long post-treatment process with the high energy consumption and waste water emission, this study provides the potentially, sustainable and novel reactive distillation (RD) process for cleanly catalytic synthesis of SK, taking into account costs and environmental impact. The ketalization kinetics experiments were carried out to provide a basis for subsequent experiments and simulations. A reliable model was established for further RD technological design and validated by the pilot-scale experiments. Through sensitivity analysis, the effects of multiplex parameters in RD process were determined. The advanced intensification of SK production by reactive dividing wall column (RDWC) achieves reduction in energy, total annual cost (TAC) and CO2 emissions of 13.9 %, 18.2 % and 16.4 % (as oil resources), respectively, compared to the optimal SK production by RD process. This proposed technology is also compared with the conventional industrial route of ketalization with 18.7 % energy saving.

In this study, we investigated electric explosion of iron wire in distilled water with different energy input adjusted by charging voltage. The as-prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS), showing the presence of iron and multiple iron-based compounds oxides with contents influenced by the experimental conditions. In particular, pure FeO(OH) nanoparticles were obtained using electric explosion of iron wire with energy input of 1125 J at charging voltage of 15 kV. Analysis of discharge current and resistive voltage data indicate that the high energy input induced by strong plasma discharge at high charging voltage is a key factor to form FeO(OH). This study presents a one-step method to synthesize FeO(OH) nanoparticles using electric explosion of iron wire.

Immune checkpoint blockade (ICB) treatment is promising for the clinical therapy of numerous malignancies. However, most cancer patients rarely benefit from such single-agent immunotherapies because of the complexity of both the tumor and tumor microenvironment. A tumor-specific liposomal vehicle (DOX-SAL) modified with a sialic acid-cholesterol conjugate (SA-CH) and remotely loaded with doxorubicin (DOX) is herein reported for improving chemoimmunotherapy. The intravenous administration of DOX-SAL dramatically downregulates tumor-associated macrophage (TAM)-mediated immunosuppression, inhibits immunoregulatory functions, and promotes intratumoral infiltration of CD8+ T cells. Compared to conventional liposomes, DOX-SAL-mediated combination therapy with a PD-1-blocking monoclonal antibody (aPD-1 mAb) almost completely eliminates B16F10 tumors and efficiently inhibits 4T1 tumors. Moreover, cancer stem cells exhibit efficient tumor-initiating, tumor-propagating, and immunosuppressive tumor microenvironment-shaping capabilities. To further improve the treatment efficacy of an immunologically "cold" tumor, metformin (MET), which selectively eradicates breast cancer tumor stem cells, is co-encapsulated with DOX into liposomes to develop DOX/MET-SAL. The combination therapy with DOX/MET-SAL and aPD-1 mAb in a 4T1 orthotopic mouse model indicates their synergetic benefit on primary tumor inhibition, metastasis suppression, and survival rate improvement. Thus, the multifunctional liposomal platform has potential value for ICB combination immunotherapy.

Ionic liquids (ILs) have shown excellent performance in the separation of binary azeotropes through extractive distillation [1]. But the role of the ionic liquid in azeotropic system is not well understood. In this paper, COSMO-RS model was applied to screen an appropriate IL to separate the binary azeotrope of ethyl acetate (EA) and ethanol and 1-octyl-3-methylimidazolium tetrafluoroborate ([OMIM][BF4]) was selected. The Quantum Mechanics (QM) calculations and molecular dynamics (MD) simulation are performed to study the interactions between the solvent molecules and [OMIM][BF4], in order to investigate the separation mechanism at the molecular level. The nature of the interactions is studied through the reduced density gradient (RDG) function and quantum theory of Atom in Molecule (QTAIM). Hydrogen bonds and van der Waals interactions are the key interactions in the complexes. The results of MD simulations indicate that the introduction of ILs has a prominent effect on the interaction between the solvent molecules, especially on reducing the number of hydrogen bonds among the solvent molecules. The radial distribution function (RDF) reveals that the interaction between the cation and solvent molecules will increase while the concentration of ILs increases. This paper provides important information for understanding the role of ILs in the separation of the azeotropic system, which is valuable to the development of new entrainers. National Key R&D Program of China (2018YFB0604900); National Natural Science Foundation of China (No. 21878219); Natural Sciences and Engineering Research Council (NSERC) of Canada (RGPIN-4903-2014); China Scholarship Council (No. 201500090106)

Green hydrogen powered polymer electrolyte membrane fuel cells (PEMFCs) seem promising for the main propulsion power of future aviation applications. This work establishes a systematic simulation tool for PEMFC studies via seamlessly embodying multiscale models from stochastic reconstruction, through pore scale modeling (PSM), to macroscale computational fluid dynamics (CFD) multi-phase and physics assessing. Using the tool, a novel angled gas diffusion layer (GDL) design, compared to the conventional multi-layer design, is proposed, simulated and studied. Stochastic reconstruction is employed in the GDL structural numerical reconstruction. PSM is charged for the effective transport properties. Results from the CFD simulations show significant gains (tens of percent) in the cell output power and limiting current under the new GDL design. PSM justifies that these gains are primarily sourced from the notable rise in the effective thermal conductivity accompanied by the moderate increase in the effective species diffusivity. PSM also predicts they can be further strengthened with larger fiber angles. All these performance boosts will further secure the competencies of PEMFCs aboard aviation applications. This study also reveals that the internal electric path of a PEMFC is already largely sufficient for the power output. On the other hand, a significant enhancement on the thermal path is still mostly lacking as a future work and to the research community.

Microwave-induced metal discharge (MMD) technology offers a novel methodology for efficient gas-phase catalytic reaction due to its unique heating effect, plasma effect and discharge effect. Herein, we successfully used a special kind of uniformly distributed particles with synergistic microwave-induced fluidized-metal discharge (MFD) effect. A lab-scale atmospheric quartz tube fluidized bed reactor was designed. Apparatus like high-speed camera, fiber spectrometer and infrared thermometer were used to record the discharge phenomena. The effects of operating conditions such as gas velocity, microwave power, carrier gas type, and metal type on the discharge behavior were investigated in detail. Subsequently, the MFD was applied into the methane dry reform reaction (MDR) with excellent conversion compared with the conventional heating conditions. Gratifyingly, the metal particles can both be the converter of microwave and the catalyst of the reaction. The reported conclusion provides a novel way to intensification the reaction process and utilize microwave energy.

Social media (e.g., Twitter) has been an extremely popular tool for public health surveillance. The novel coronavirus disease 2019 (COVID-19) is the first pandemic experienced by a world connected through the internet. We analyzed 105+ million tweets collected between March 1 and May 15, 2020, and Weibo messages compiled between January 20 and May 15, 2020, covering six languages (English, Spanish, Arabic, French, Italian, and Chinese) and represented an estimated 2.4 billion citizens worldwide. To examine fine-grained emotions during a pandemic, we built machine learning classification models based on deep learning language models to identify emotions in social media conversations about COVID-19, including positive expressions (optimistic, thankful, and empathetic), negative expressions (pessimistic, anxious, sad, annoyed, and denial), and a complicated expression, joking, which has not been explored before. Our analysis indicates a rapid increase and a slow decline in the volume of social media conversations regarding the pandemic in all six languages. The upsurge was triggered by a combination of economic collapse and confinement measures across the regions to which all the six languages belonged except for Chinese, where only the latter drove conversations. Tweets in all analyzed languages conveyed remarkably similar emotional states as the epidemic was elevated to pandemic status, including feelings dominated by a mixture of joking with anxious/pessimistic/annoyed as the volume of conversation surged and shifted to a general increase in positive states (optimistic, thankful, and empathetic), the strongest being expressed in Arabic tweets, as the pandemic came under control.

In practical applications of graph theory, indeterminacy factors always appear in graphs. Uncertain random graph was proposed via chance theory, in which some edges exist with degrees in probability measure and others exist with degrees in uncertain measure. This paper discusses the contributions of edges for connectivity of an uncertain random graph and proposes concepts about significance of edges, according to which edges are classified. In addition, this paper presents algorithms for calculating connectivity index and significance of edges of an uncertain random graph. Examples are given to illustrate algorithms and methods.

Microchemical technology shows prospect in the process intensification field of carbon capture and storage, however, there remain great challenges in microchemical technology for gas-liquid mass transfer with counter-current flow. In this work, we proposed a micro-apparatus with confined structure for gas-liquid counter-current flow mass transfer. The flow patterns on the confined structure, steady flow and bead flow, were observed, furthermore, the critical flow rate between them was measured. The influences of confined structure geometry, surface tension and viscosity of liquid on the meniscus at the gas-liquid interface were studied. The operation window of micro-apparatus with different types of confined structures was examined. The liquid loading and gas loading of micro-apparatus with S1005 were tested to be 230 μL/min and 500 mL/min, respectively. The system of absorption of pure CO2 in a 1 M NaOH solution was used to study the mass transfer. The average liquid side mass transfer coefficient of 25.1 × 10−5 m/s was measured at liquid flow rate of 30 μL/min and gas flow rate of 300 μL/min, which proves that the micro-apparatus achieves the process intensification of CO2 absorption.

Enantiopure esomeprazole is an important drug in the treatment of gastric ulcer. The asymmetric sulfoxidation of omeprazole thioether was catalyzed by immobilized cells of a mutant of Rhodococcus rhodocrous ATCC 4276 to synthesize esomeprazole. The bioreaction was carried out in a biphasic system (chloroform-water), at a high substrate concentration (200 mM), and optimized using response surface methodology (RSM). The optimal yield of esomeprazole obtained was 94.8% with e.e. (>99%) without the formation of the sulfone form as a byproduct, under the optimal conditions: the concentration of immobilized cells, 283.5 g/L, the incubation temperature, 37.05 °C, and pH of phosphate buffer, 7.35, respectively. A quadratic polynomial model was developed with R2 of 0.9998, which indicates that the model predicts the observed data with very high accuracy. The mutant exhibited a high enantioselective activity and substrate and product tolerance. The small size of immobilized cell beads (0.5–1 mm) creates a large reaction interface. The aerated flask provides enough oxygen for a high concentration of cells. The significant improvement of substrate tolerance may mainly be attributed to employing the chloroform-water biphasic system because organic substrates may be partitioned in the organic phase, eliminating potential damage and inhibition to cells. Based on the above, the asymmetric sulfoxidation catalyzed by immobilized bacterial cells is therefore more promising for efficient synthesis of chiral sulfoxides.

A novel, three-dimensional filter based on corn stalk (CS) was prepared by in-suit growing ZnO nanoparticles (NPs) for potential water sterilization. The hierarchical mesostructure consisting of vessels and parenchymas facilitated the diffusion of Zn2+ and immobilization of ZnO NPs. The different zinc sources influenced various morphology and chemical characteristics of ZnO loaded in CS, leading to a variety of antibacterial activities. The nanocomposites from Zn(NO3)2, exhibited high rates for killing both Escherichia coli (>99.2%) and Staphylococcus aureus (>95.4%) through the short-time filtration. The antimicrobial mechanism of CS/ZnO was owed to interception of the bacteria by a porous architecture of CS. Thus, it enhanced the bactericidal efficiency of nano ZnO through physical friction, chemical reactions with reactive oxygen species (ROS) and penetration of zinc-hydrated ions. Consequently, deformation of the cell membranes, leakage or damage of intercellular components caused the death of bacteria.

For the purpose of resolving issues of high production costs due to targeting intermediate products from tandem reaction systems in the isobutylene (IB) dimerization process with tert-butanol as a ...

Here, a novel nitrogen-doped carbon nano-material (N-CGNM) with hierarchically porous structure was prepared from spent coffee ground for efficient adsorption of organic dyes by a simple one-step carbonization process (the uniform mixture consists of spent coffee ground, urea, and CaCl2 with the ratio of 1:1:1, which was heated to 1000 °C with a rate of 10 °C min−1 and held at 1000 °C for 90 min in N2 atmosphere to carry out carbonization, activation, and N-doping concurrently). The morphology and structure analysis show that the prepared N-CGNM exhibits hierarchical pore structure, high specific surface area (544 m2/g), and large numbers of positively charged nitrogen-containing groups. This unique structure and chemical composition endow N-CGNM with an excellent adsorption capacity toward anion Congo red (623.12 ± 21.69 mg/g), which is obviously superior to that (216.47 ± 18.43 mg/g) of untreated spent coffee ground-based carbon nano-materials (CGM). Oppositely, the adsorption capacity of N-CGNM towards cation methylene blue is inferior to that of CGM due to the existence of electrostatic repulsion. These findings show a great guidance for the development of low-cost but efficient selective adsorbent.

Flash flood disaster, with strong suddenness and tremendous destructiveness, is one of the most severe natural disasters in China that seriously threaten the lives and property safety of people and social development. Owing to the complex terrain and limited rainfall and runoff monitoring gauges, it is arduous to effectively prevent and control flash flood disasters in small-sized and medium-sized hilly watersheds. Identifying rainfall threshold, critical discharge and warning periods for flash flood, is critical in disaster prevention in such regions. This study adopted two approaches, the entropy-based decision approach and the hydrological model approach in calculating rainfall thresholds under different antecedent moisture condition (AMC). In particular, the entropy-based decision approach was improved, by using the Frank copula to calculate the multivariate joint distribution of the cumulative rainfall and the corresponding peak discharge. These two approaches were validated in a typical basin, located in the Pearl River Delta in South China that is characterized by frequently heavy rainfall and floods in the monsoon. Results showed that both approaches have the ability to quantify rainfall thresholds. Relatively, the Bayesian method exhibited higher rainfall thresholds, comparing to the other methods. In particular, for AMC I, the utility-entropy risk function method (with λ = 1) exhibited the best-applied practicable forecast lead time of 2.0 h; as for AMC II, the two methods showed the same forecast lead time of 1.5 h, and for AMC III, the hydrological model-based approach showed an optimal forecast lead time of 6.0 h. Meanwhile, the entropy-based approach exhibited the same performance as hydrological modeling approaches, indicating that this method is practicable in flood forecasting. The results would be helpful for floods prevention and mitigation in such small-sized and medium-sized hilly watersheds.

This paper presents a novel 2D/3D non-rigid registration method for lung lesions tracking in image-guided diagnoses and treatments. Preoperative 3D lung CT volumes were obtained at a series of respiratory phases and important anatomical points were extracted. A CT volume was selected as reference volume and others were considered floating volumes. Displacement vectors of anatomical points were calculated using coherent point drift (CPD) and diffeomorphic-demon methods. For each CT volume, 2D digitally reconstructed radiographs (DRR) were generated by ray projection to simulate intraoperative 2D X-ray, and grayscale-based similarity measures of DRR between reference and floating volumes were calculated. A pulmonary respiration model was constructed using cubic polynomial, which represents the non-linear correlation between displacement vectors and similarity measures. During operation, the pulmonary respiration model used X-ray to obtain displacement vectors of important anatomical points; deformation fields were calculated from the displacement vectors through B-spline transformations. Finally, simulated lung CT volumes corresponding to intraoperative X-ray were generated by applying deformation fields to reference volume. The proposed method was compared to a state-of-the-art 2D/3D non-rigid registration method named respiratory-phase matching. Experimental results on two datasets respectively from a lung cancer patient and an ex vivo pig lung, showed mean registration accuracy of the proposed method was 1.57 ± 0.92 mm and 2.65 ± 1.35 mm; an improvement of 23% and 9% over the matching method. Moreover, mean lung structure overlaps were 0.91 and 0.88, comparable to matching method. The proposed method has potential in aiding lung intervention diagnoses and real-time lesion tracking.

This paper aims at intensifying the synthesis process of solketal by the reactive dividing wall column (RDWC) through experiments and simulation optimization and proposes a high-efficiency producti...

The electron backscatter electron diffraction (EBSD) technique was applied to study the microstructure evolution and properties of the annealed cold rolling C71500 cupronickel alloy tube. The fixed reduction ratio of C71500 alloy tube was 23.71%. After rolling with different thickness reduction, the change process of grain, the evolution of texture, the characteristic distribution of grain boundary and the mechanical properties of the alloy tube were discussed systematically. The texture of cold rolling tube was obviously different from the drawing and sheet textures, and only the textures of RZ{111 type and R-cube{001} type could be observed after the two roller cold rolling process. After a certain amount of deformation, obvious accumulated orientation differences could be seen in the textures, which could create favourable conditions for the recrystallization nucleation. In the rolling process, the nonuniformity deformation of tube was caused by the inconsistency of stress state. With the increase reduction of tube wall, the tensile strength of the alloy increased from 405.13 to 574.65 MPa, the yield strength increased from 310.35 to 338.76 MPa, and the micro-Vickers hardness increased from 137.40 to 186.01.

The geographical detector model (GDM) is based on the spatial variance analysis of geographical strata of variables to assess the association between the independent variables (X) and dependent var...

Perovskite solar cells have driven a paradigm shift in the research domain of photovoltaics. Although the field has progressed tremendously, device stability holds back further progress and applica...

Two-stage rolling process was adopted to study the texture and special grain boundary distribution of C71500 copper-nickel alloy tubes at different annealing temperatures. The effect of temperature on the texture of C71500 copper-nickel alloy tube was analyzed. The hardness analysis was used to study the recrystallization and low lattice reconstruction grain boundaries ratio at different temperatures. It was observed by electron backscattered diffraction that static recovery of the alloy tube occurs when the annealing temperature below 800 °C and it transforms into static recrystallization at 825 °C. The initial strain-induced grain boundary migration temperature of alloy tube is about 775 °C. The number of Copper{112} textures can be used to determine the ratio of the low coincidence site lattice (low ΣCSL) grain boundary. The optimal annealing process for C71500 alloy tube to obtain a high proportion of special grain boundaries is to keep the temperature at 800 °C for 15 min.

Mechanochemical ball milling can degrade high concentrations of persistent organic pollutants (POPs) in contaminated soil and even pure chemicals easily and efficiently. There are many relevant laboratory studies that discuss the selection of reagents and mechanism of pollutant degradation. However, there are few related studies on large-scale treatment and importance of collision energy in the system. The purpose of this study is to optimize the existing collision model and design horizontal ball mill to examine the influence of the internal structure on the collision energy. Studies have shown that not only the collision between balls, but also the collision between the balls and internal structure (balls and blades, balls and cylinder) accounts for a considerable proportion in the system. Besides, we found that the single impact energy determines whether the mechanochemical reaction occurs and the effective collision power determines the mechanochemical reaction rate during ball milling. Finally, we calculated that the effective collision power increases as the number of blades and blade-mill volume ratio, and different operating modes influence collision power significantly when the number of blades and blade-mill volume ratio exceed a certain threshold.

For systems that are based on network function virtualization (NFV), it remains a key challenge to conduct effective service chain composition with the lowest request latency and the minimum network congestion. In such an NFV system, users are usually non-cooperative, i.e., they compete with each other to optimize their own benefits. However, existing solutions often ignore such non-cooperative behaviors of users. What is more, they may fall short in the face of unexpected resource failures such as breakdown of virtual machines and loss of connections to users. In this article, we formulate the service chain composition problem with resource failures in NFV systems as a non-cooperative game , and show that such a game is a weighted potential game , aiming to search for the optimal Nash equilibrium (NE). By adopting Markov approximation techniques, we devise a distributed scheme called MH-SCCA, which achieves a provably near-optimal NE and adapts to resource failures in a timely manner. For comparison, we also propose two baseline schemes (DRL-SCCA and MCTS-SCCA) for centralized service chain composition that are based on deep reinforcement learning (DRL) and Monte Carlo tree search (MCTS) techniques, respectively. Our simulation results demonstrate the effectiveness of the three proposed schemes in terms of both latency reduction and congestion mitigation, as well as the adaptivity of MH-SCCA when faced with resource failures.

The influence of sulfur on the hot compression properties of C71500 cupronickel alloy and the mechanism of thermo mechanical effect are studied for the first time. The composition of sulfide inclusions and its damage mechanism to properties were also studied. The effect of sulfur content on the dynamic recrystallization activation energy and the properties of the alloy was deduced and explained systematically. The relationship between the dynamic recrystallization activation energy and sulfur content was obtained, and a energy dissipation model was established based on the dynamic material model. The Prasad’s instability criterion was used to predict the unstable region in the processing chart. The effect of sulfur on the processing parameters selection was compared under different strain conditions, which could provide the ideal processing technology for the thermal deformation of C71500 alloy with various sulfur content.

Safety issues associated with lithium-ion batteries are of major concern, especially with the ever-growing demand for higher-energy-density storage devices. Although flame retardants (FRs) added to electrolytes can reduce fire hazards, large amounts of FRs are required and they severely deteriorate battery performance. Here, we report a feasible method to balance flame retardancy and electrochemical performance by coating an electrolyte-insoluble FR on commercial battery separators. By integrating dual materials via a two-pronged mechanism, the quantity of FR required could be limited to an ultrathin coating layer (4 μm) that rarely influences electrochemical performance. The developed composite separator has a four-times better flame retardancy than conventional polyolefin separators in full pouch cells. Additionally, this separator can be fabricated easily on a large scale for industrial applications. High-energy-density batteries (2 Ah) were assembled to demonstrate the scaling of the composite separator and to confirm its enhanced safety through nail penetration tests.

In this paper, fatty acid ethyl ester (FAEE) was enzymatically produced from the waste oil and ethanol. It was investigated under three different conditions: ultrasound, deep eutectic solvent (DES) and ultrasound-assisted DES. The effects of lipase dosage, alcohol oil ratio, reaction temperature, ultrasonic power, reaction time and DES dosage on the conversion rate of FAEE were explored. The ultrasonic-assisted DES optimization experiment was carried out through the response surface experiment with five factors and three levels. The experimental results showed that the conversion of FAEE was significantly improved and the reaction time was shortened under the ultrasound-assisted DES system, the ultrasonic power and reaction temperature had synergistic effect on the conversion of FAEE. The conversion rate of FAEE reached 93.61 ± 0.46% on the condition of reaction temperature 59 °C, ultrasonic power 80 W, and reaction time 137 min with addition of 6.4% lipase and 4 mmol alcohol for 1 g oil.

As a promising ammonia synthesis approach to replace the industrial Harber method, the biggest problem restricting photocatalytic nitrogen fixation is the suboptimal efficiency. Herein, novel surface oxygen vacancies modified micro-nanosheet structure Bi2O2CO3 (namely BOC/OV) were successfully synthesized via facile formation under room temperature. These defects-rich nanosheets exhibit outstanding performance for photocatalytic nitrogen fixation under visible light. The surface oxygen vacancies provide abundant active sites for molecular N2 activation, and the effect of scattered nanometer-size could facilitate the separation of photo-generated charges. Moreover, the energy band can be consecutively tuned with the accumulation of surface oxygen vacancies by lowering the conduction band position. Among all as-prepared samples, BOC/OV3 exhibited the highest NH4+ yield, reaching 1178 μmol·L−1·g−1·h−1, which is 10 times than that of pristine Bi2O2CO3. In this work, all samples synthesis and defects formation were conducted without requiring any secondary energy, which is of great significance for realizing green and efficient artificial ammonia synthesis.

1,2-Butene carbonate (BC) is an important five-membered cyclic carbonate with a high commercial value, but its massive production is limited by the lack of raw material 1,2-butanediol (1,2-BDO). 1,...

It is important for the development of high-performance dielectric materials to reduce the dielectric constant and water uptake simultaneously, with the maintenance of mechanical properties. Herein, sandwich-type composite film was prepared through coating the both sides of flat polyimide (PI) film with polyhedral oligomeric silsesquioxanes (POSS) contained hierarchical porous structure using the microemulsion method, in which water droplets were used as the template for patterned pores. Due to the introduction of two layers of hierarchical porous structure with patterned pores and POSS, the dielectric constant of PI film was significantly reduced, accompanied by the low dielectric loss. In addition, the water uptake was also greatly reduced, thus contributing to its excellent durability under high humidity. More importantly, even with the introduction of porous structure, the mechanical properties of PI film can still be maintained, or even improved by optimizing POSS content. Through varying the POSS content from 10 to 50%, low dielectric constant of 2.28–2.42, dielectric loss of 0.005–0.009, water uptake of 0.56–0.62%, increment of dielectric constant under high humidity of 1.19–2.35%, with 26–32%, 43–69%, 77–80% and 31–37% of reduction, respectively, compare to flat PI film were achieved. These results indicate the potential of our sandwich-type composite film as low dielectric material in microelectronics.

Motivation Electron tomography (ET) has become an indispensable tool for structural biology studies. In ET, the tilt series alignment and the projection parameter calibration are the key steps toward high-resolution ultrastructure analysis. Usually, fiducial markers are embedded in the sample to aid the alignment. Despite the advances in developing algorithms to find correspondence of fiducial markers from different tilted micrographs, the error rate of the existing methods is still high such that manual correction has to be conducted. In addition, existing algorithms do not work well when the number of fiducial markers is high. Results In this article, we try to completely solve the fiducial marker correspondence problem. We propose to divide the workflow of fiducial marker correspondence into two stages: (i) initial transformation determination, and (ii) local correspondence refinement. In the first stage, we model the transform estimation as a correspondence pair inquiry and verification problem. The local geometric constraints and invariant features are used to reduce the complexity of the problem. In the second stage, we encode the geometric distribution of the fiducial markers by a weighted Gaussian mixture model and introduce drift parameters to correct the effects of beam-induced motion and sample deformation. Comprehensive experiments on real-world datasets demonstrate the robustness, efficiency and effectiveness of the proposed algorithm. Especially, the proposed two-stage algorithm is able to produce an accurate tracking within an average of ⩽ 100 ms per image, even for micrographs with hundreds of fiducial markers, which makes the real-time ET data processing possible. Availability and implementation The code is available at https://github.com/icthrm/auto-tilt-pair. Additionally, the detailed original figures demonstrated in the experiments can be accessed at https://rb.gy/6adtk4. Supplementary information Supplementary data are available at Bioinformatics online.

Phased array antennas have played a very important role in many different areas and applications. It requires precise excitation of each antenna element by various synthesis techniques to obtain desired array pattern features. However, due to reasons such as manufacturing imperfections, component aging, and temperature variation, the realistic antenna element excitation inevitably differs from their expected values in practice. This paper presents a tutorial-like review to deal with excitation errors for phased array antennas. Two kinds of analysis methods, probabilistic methods and interval arithmetic (IA) based methods, are presented to evaluate the effects of excitation errors for phased array antennas. State-of-the-art calibration methods along with various signal processing techniques are reviewed, their advantages and challenges are discussed in a comparative manner. Some other common errors and open research directions are also presented.

The green hard capsules were prepared with corn nano-starch (CNS) and cellulose nanocrystal (CNC) in this study, the glycerol and carrageenan were used as plasticizer and gelling agent in the CNS/CNC gel solution, respectively. The capsule-films with different CNC content were prepared by casting method, and the dipping method was used in preparation of the corresponding capsules. The compatibility of CNS/CNC capsules was analyzed by Fourier Transform Infrared spectroscopy (FTIR) and X-Ray Diffraction (XRD), and the morphology of the capsules was analyzed by Scanning Electron Microscopy (SEM). The results showed that the tensile strength of the CNS based capsule-film was significantly improved with the addition of CNC. When the content of CNC was 6.0%, the tensile strength increased by 238.10%. The transparency of the capsule with different CNC contents was slightly reduced, but was greater than 87.0%. The loss on drying of CNS/CNC capsule was between 12.87% and 15.03%, and it could be completely dissolved in the artificial gastric juice within 6.0 min, which was in accordance with the provisions of Chinese Pharmacopoeia (2015).

The detection of Thermal Power Plants (TPPs) is a meaningful task for remote sensing image interpretation. It is challenging due to the variations in appearance and complex structures. In this article, we propose a novel end-to-end detection framework for TPPs based on deep convolutional neural networks. Specifically, a large-scale TPPs Dataset for Detection (AIR-TPPDD) in remote sensing images is presented. AIR-TPPDD is collected from the Google Earth worldwide, and provides detailed annotations including names and locations. To the best of our knowledge, this is the first publicly available dataset for TPP detection. Then, based on Faster R-CNN, a saliency enhanced module is proposed to strengthen the ability in representing complex structure, as well as alleviate distractions in the background. In addition, we design a multi-scale feature module to adapt to the large size range of TPPs. Experiments show that the proposed method outperforms the state-of-the-art methods and achieves 76.7% mAP on the challenging AIR-TPPDD.

Microalgae is promising to be used as feedstock resources for hydrogen production due to its high oil and grease contents. This promotes the development of extraction technology of microalgae oil. In this study, based on the Rayleigh-Plesset equation, the effects of temperature, pressure, ultrasonic power and frequency on the bubble motion of ethanol ultrasound cavitation are investigated. Subsequently, the effects of different process parameters on the extraction rate are studied using Schizochytrium sp. as raw material by stirring or ultrasonic-assisted extraction. And the composition of algae extraction oil is analyzed. The results show that the amplitude of cavitation bubbles increases with the increase of ultrasonic power and decrease of ultrasonic frequency. The extraction rate of algae oil reaches 93.76 ± 0.48% when the ultrasonic power is 150 W, the reaction time is 30 min, the temperature is 50 °C and the liquid-solid ratio is 10:1.

We have developed an in situ bioprinting method that allows the printing of cells under true physiological conditions by applying self-assembling ultrashort peptides as bioinks. This method avoids cell stressing methods, such as UV-treatment, chemical crosslinking and viscous bioink printing methods. We further demonstrate that different nanomaterials can easily be synthesized or incorporated in the 3D bioprinted peptide scaffolds which opens up the possibility of functionalized 3D scaffolds.

Cage-type control valves are widely used in process industries, but cavitation can occur when the valves are used in extreme high-pressure drop and large volume flow rate conditions. In this study, the cage-type control valve with improved valve cages is introduced, and its flow and cavitation characteristics are compared with other cage-type control valves with no dead zones in the regulation process. Two cage numbers and four valve cage structures are studied. Numerical simulations are conducted, and their accuracy is validated using experimental results. Results show that cage-type control valves with valve cage 1 have the maximum flow coefficient and cavitation intensity under the same cage number. Cage-type control valves with valve cage 2 have the minimum flow coefficient but medium cavitation intensity. While cage-type control valves with improved valve cages have a medium flow coefficient but minimum cavitation intensity, and water vapor volume can be reduced by 2–8 times compared with cage-type control valves with the valve cage 2. Furthermore, for cage-type control valves with improved valve cages, the cavitation intensity, and flow coefficient decrease as the cage number and groove height increase.

The hot tensile test was applied to study the influence of sulfur content on the high-temperature mechanical properties of C71500 Cu-Ni alloy. The hot processing map of C71500 alloy was established according to the test results. It is found that the increase of sulfur content has no visible effect on the tensile strength of C71500 alloy at high temperature, but has a great effect on the elongation and reduction area of fracture. Through optical microscopy, scanning electron microscopy and energy-dispersive x-ray spectroscopy analysis of fracture samples, it can be qualitatively determined that the composition of sulfur inclusions is (Mn,Fe,Ni)S, which is plastically deformable in the process of hot deformation. However, due to the difference of plasticity between the inclusions and the matrix, stress concentration is easy to occur, thus reducing the overall plasticity of C71500 alloy. Based on the proposed dynamic material model theory, the processing maps with different sulfur contents were established, which could show the destruction effect of sulfur on the high-temperature plastic deformation of C71500 alloy.

As the prevalence of plastic micro- and nanoparticles in the environment, foods, and beverages continues to increase, the risk of human exposure to and uptake of such particles, notably via ingestion or inhalation, is also elevated. Despite this development, relatively little is known about the potential adverse effects of plastic particles on humans. The lack of relevant plastic nanoparticles for use in studies investigating their behavior and effect on human cells is a key hurdle that must be overcome prior to generating hazard data. We herein demonstrate the creation of fluorescent nanoparticles of the thermoplastic polymers poly(ethylene terephthalate), polypropylene, and polystyrene. The particles were produced by melt-processing and milling. The analysis of scanning electron microscopy images showed core diameters of less than 75 nm. Furthermore, the images revealed that the milled particles had highly heterogeneous shapes, as is often seen in environmental samples. The particles were exposed to relevant cell lines (i.e. Caco-2 intestinal epithelial cells and J774A.1 macrophages) to determine their uptake, assessed by confocal laser microscopy, and biocompatibility, assessed by measuring the release of lactate dehydrogenase. Exposure data showed no cytotoxicity at the concentrations utilized in this study. Interaction of the particles was found to be cell type dependent, with agglomeration on the apical surface and few intracellular particles in the intestinal epithelial cells in comparison to numerous internalized particles in the macrophages. In conclusion, the herein presented melt-processing and milling methods resulted in heterogeneously shaped plastic nanoparticles with a fluorescence label allowing their behavior within a complex biological environment to be studied.

The need for the separation of azeotropic mixtures for the production of high-end chemicals and resource recovery has spurred significant research into the development of new separation methods in the chemical industry. In this paper, a green and sustainable method for azeotrope separation is proposed based on a chemical-looping concept with the help of reversible-reaction-assisted distillation. The central concept in the chemical-looping separation (CLS) method is the selection of a reactant that can react with the azeotrope components and can also be recycled by the reverse reaction to close the loop and achieve cyclic azeotrope separation. This paper aims to provide an informative perspective on the fundamental theory and applications of the CLS method based on the separation principle, reactant selection, and case analysis, for example, the separation of alkenes, alkane, aromatics, and polyol products. In summary, we provide guidance and references for chemical separation process intensification in product refining and separation from azeotropic systems for the development of a more sustainable chemical industry.

In this work, the effect of pH and potential is examined for the oxidation of carbon cloth electrodes used in capacitive deionization (CDI) processes. The degree of oxidation of the electrode surface, examined using the electrode's potential of zero charge (Epzc) and measured using chronoamperometry and cyclic voltammetry, is found to be strongly correlated to the pH of the solution at the interface. Local pH measurements are examined at anodes and cathodes in full CDI and membrane-assisted capacitive deionization (MCDI) cells at cell voltages ranging from 0.3–1.2 V. The cathode is shown to be basic under charging potentials while the anode is found to be acidic. This local pH is found to be highly transient during charging and discharging in CDI cells while the pH is found to be relatively static in the MCDI cells, maintaining a basic pH at the cathode and an acidic pH at the anode even when the cell is discharged. Ion exchange membranes (IEM) are found to have two functions: (1) limiting co-ion expulsion that results from specific ion adsorption and (2) limiting the effects of parasitic Faradaic reactions on the separation process by stabilizing the local pH thereby mitigating dissolved oxygen reduction at the cathode and lessening carbon oxidation at the anode. Performance comparisons including the salt adsorption capacity and charge efficiency are also compared for these systems.

Due to open-cell foam materials have extensive application foreground in medium-low pressure drop reactors or reactive distillation with low liquid load operation, it has been a hot spot in this field to explore the liquid phase flow inside the pores of foam materials. The present investigation addresses the formation conditions of the vortex flow in matrix porous structure (MPS) that is made from 3D printing technology. An experimental system consisting of a high-speed camera with a macro lens and particle tracking system was used to investigate the effect of the liquid flow rate and the liquid viscosity on the vortex flow formation in MPS. The numerical analysis based on the CFD modeling was used to calculate the vortex flow behaviors and characteristics. This model is validated and compared with the results of experimental campaigns performed in MPS with the formation of stable vortex flow. It was also found that the radius and swirling velocity of the vortex can be decreased by increasing the liquid viscosity and it would be slightly affected by main flow velocity with 10 mL/min – 100 mL/min, which is helpful to construct the gas-liquid interface with the formation of vortex flow for realizing process intensification.

The balance between high accuracy and high speed has always been a challenging task in semantic image segmentation. Compact segmentation networks are more widely used in the case of limited resources, while their performances are constrained. In this paper, motivated by the residual learning and global aggregation, we propose a simple yet general and effective knowledge distillation framework called double similarity distillation (DSD) to improve the classification accuracy of all existing compact networks by capturing the similarity knowledge in pixel and category dimensions, respectively. Specifically, we propose a pixel-wise similarity distillation (PSD) module that utilizes residual attention maps to capture more detailed spatial dependencies across multiple layers. Compared with exiting methods, the PSD module greatly reduces the amount of calculation and is easy to expand. Furthermore, considering the differences in characteristics between semantic segmentation task and other computer vision tasks, we propose a category-wise similarity distillation (CSD) module, which can help the compact segmentation network strengthen the global category correlation by constructing the correlation matrix. Combining these two modules, DSD framework has no extra parameters and only a minimal increase in FLOPs. Extensive experiments on four challenging datasets, including Cityscapes, CamVid, ADE20K, and Pascal VOC 2012, show that DSD outperforms current state-of-the-art methods, proving its effectiveness and generality. The code and models will be publicly available., Comment: Published in IEEE Transaction on Image Processing (TIP) 2021, Volume: 30

Before the rock mass in the engineering is broken under load, it is usually in a state of varying degrees of damage. Aiming at the fracture characteristics of damaged sandstone under impact load, this paper adopts a method of the cyclic static load to cause the sandstone specimens to have varying degrees of damage. Then, the wave velocity of sandstone before and after the damage is measured using the nonmetallic acoustic velocimeter, and the change rule of damage factor is analyzed. Finally, the split Hopkinson pressure bar (SHPB) is used to test the impact dynamics of sandstone with different damage degrees. The broken rock block is screened by a vibrating screen, and the crushing characteristics are analyzed. The results show that not only the damage factor of damaged sandstone but the growth rate increases, with the raising upper limit of stress. Under the impact load of the same incident energy, the fragmentation degree of the damaged sandstone increases with the increase of the upper stress limit, while the average diameter of the broken rock block decreases gradually, and the reduction rate increases first and then decreases.

Corona discharge thrusters (CDTs) bear a potential for silent and mechanically simple aerial propulsion. In this work, we propose an aircraft engine that combines CDTs and low temperature polymer electrolyte membrane fuel cells (LT-PEMFCs). A model is then developed in parametric studies to study its performance. Especially, potential synergies due to emission and utilization of ozone and water, are focused. In addition, the influence of ambient conditions, a such-equipped aircraft might encounter, is examined. The engine shows a high sensitivity to ambient temperature and humidity, rendering the effectiveness of such a propulsion system strongly dependent on the environment it is located in. On the other hand, the produced water and ozone promises a limited impact on engine efficiency. Although thrust levels produced by CDTs are still low, the combination of the technologies seems promising for light-weight aircrafts.

Kernel selection is of fundamental importance for the generalization of kernel methods. This article proposes an approximate approach for kernel selection by exploiting the approximability of kernel selection and the computational virtue of kernel matrix approximation. We define approximate consistency to measure the approximability of the kernel selection problem. Based on the analysis of approximate consistency, we solve the theoretical problem of whether, under what conditions, and at what speed, the approximate criterion is close to the accurate one, establishing the foundations of approximate kernel selection. We introduce two selection criteria based on error estimation and prove the approximate consistency of the multilevel circulant matrix (MCM) approximation and Nyström approximation under these criteria. Under the theoretical guarantees of the approximate consistency, we design approximate algorithms for kernel selection, which exploits the computational advantages of the MCM and Nyström approximations to conduct kernel selection in a linear or quasi-linear complexity. We experimentally validate the theoretical results for the approximate consistency and evaluate the effectiveness of the proposed kernel selection algorithms.

We have studied the evaporation of water droplets containing silica nanoparticles of various hydrophobicities deposited on a super-hydrophobic substrate. Evaporation induces particle accumulation at the droplet surface and results in the formation of a crust that buckles during further shrinkage. For droplets containing hydrophilic particles, a bowl-shaped crust was observed. For droplets containing hydrophobic particles, the crust develops a multi-buckled shape that could be completely suppressed by increasing the relative humidity. The varied buckling behavior of droplets may be attributed to the different mechanical properties of the gelled layer where particle hydrophobicity plays a role. Our work highlights the important role of particle hydrophobicity and relative humidity in the final crust morphology, thus shedding light on crust shape control and material design via the droplet evaporation approach.

A computational model for an ozone oxidation column reactor used in dyeing wastewater treatment is proposed to represent, simulate, and predict the ozone bubble process. Considering the hydrodynamics, mass transfer, and ozone oxidation reaction, coupling modeling can more realistically calculate the ozone oxidation bubble process than the splitting methods proposed in previous research. The modeling is validated and shows great consistency with experimental data. The verified model is used to analyze the effect of operating conditions, such as the initial gas velocity and the ozone concentration, and structural conditions, such as multiple gas inlets. The ozone consumption is influenced by the gas velocity and the initial ozone concentration. The ozone’s utilization decreases with the increasing gas velocity while nearly the same at different initial ozone concentrations. Simulation results can be used in guiding the practical operation of dyeing wastewater treatment and in other ozonation systems with known rate constants in wastewater treatment.

The isothermal compression test was employed to study the influence of deformation temperature and strain rate on the hot deformation behavior of C71500 copper-nickel alloy. According to the characteristics of dynamic recovery (DRV) and dynamic recrystallization (DRX), the Zener–Hollomon parameter lnZ is used as an important parameter to measure the influence of temperature and strain rate on the hot deformation behavior. The critical deformation conditions of DRX are determined by its different values. By analyzing the critical change of work hardening rate, the relationship among critical stress, peak stress and saturation stress transition point is obtained, and the dynamic mathematical model of the whole deformation process is established, which can predict the volume fraction of DRV and DRX well. The DRX nucleation and growth mechanism of C71500 copper-nickel alloy was determined by metallographic analysis. In the current work, the thermodynamic parameters are introduced to determine the critical conditions of the transformation of the deformation state, the transformation process of the hot deformation structure is predicted by the dynamic model, the nucleation and growth mechanism is analyzed, which could provide a complete set of important references for the DRV-based hot deformation alloy, and provide a theoretical basis for the control of the structure state after hot processing.

9α-Hydroxy-4-androstene-3,17-dione (9OHAD), formed by the 9α-hydroxylation reaction catalyzed by 3-ketosteroid-9-hydroxylase (KSH), is an important precursor for the synthesis of adrenocortical hor...

Inactive components and safety hazards are two critical challenges in realizing high-energy lithium-ion batteries. Metal foil current collectors with high density are typically an integrated part of lithium-ion batteries yet deliver no capacity. Meanwhile, high-energy batteries can entail increased fire safety issues. Here we report a composite current collector design that simultaneously minimizes the ‘dead weight’ within the cell and improves fire safety. An ultralight polyimide-based current collector (9 μm thick, specific mass 1.54 mg cm−2) is prepared by sandwiching a polyimide embedded with triphenyl phosphate flame retardant between two superthin Cu layers (~500 nm). Compared to lithium-ion batteries assembled with the thinnest commercial metal foil current collectors (~6 µm), batteries equipped with our composite current collectors can realize a 16–26% improvement in specific energy and rapidly self-extinguish fires under extreme conditions such as short circuits and thermal runaway. Batteries need to be energy-dense as well as safe. Yi Cui and team develop an ultralight polyimide-based current collector with embedded fire retardants that enables lithium-ion batteries with much-enhanced safety and energy density.