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Study Design Basic researchObjective To prepared 3 DNPM/chitosan hybrid hydrogels and chose the best DNPM/chitosan hybrid hydrogel for NP tissue engineering.Methods Three DNPM/chitosan hybrid hydrogels were fabricated by changing the ratio of the decellularized NP matrix to chitosan and crosslinking with genipin. NP stem cells (NPSCs) were cultured on the hybrid hydrogels and their proliferation, morphology, and gene expression were evaluated. Finally, an in vivo experiment was performed to evaluate the immune response to the hydrogels.Results The adhered NPSCs proliferated well on the hybrid hydrogel. The gene expression of NP-related collagen type II, aggrecan, and Sox-9 from NPSCs cultured on DNPM/chitosan hybrid hydrogel-1 was greater than from cells cultured on DNPM/chitosan hybrid hydrogel-2 and DNPM/chitosan hybrid hydrogel-3. Few inflammatory cells were observed during the in vivo experiment with DNPM/chitosan hybrid hydrogel-1.Conclusions DNPM/chitosan hybrid hydrogel-1 is a potential candidate scaffold for NP tissue engineering.

In this paper, a novel magnetization state (MS) control method is proposed by utilizing torque deviation to achieve the MS closed-loop control for variable flux memory machine. Firstly, the relationship between the MSs and the demand magnetizing current pulses is built into a look-up table, which also contains information on the flux linkages and the dq-axis inductances under different MSs. Afterwards, a model-based torque calculation is adopted for torque estimation, and then, the torque deviation between the present MS and the target MS can be obtained and utilized to generate the MS switch signal, which will determine the type of MS manipulation. Subsequently, the calculated torque will also be used for real-time monitoring of MS. The feasibility of the proposed MS control method is verified by simulation. Finally, experiments are carried out on a hybrid magnet memory machine control system for validation.

In this work, the bending behavior of high-strength Al–Mg–Si–Cu alloys and AA6061 under different artificial aging condition was investigated. The existing springback prediction formula is suitable for commercial AA6061 alloy, but not for high-strength Al–Mg–Si–Cu alloy. Subsequently, the microstructure, mechanical properties and residual stress of AA6061 and high-strength Al– Mg–Si–Cu alloys were investigated. The results show that the yield strength and residual stress play important roles on the springback of high-strength Al–Mg–Si–Cu alloy. In addition, a springback prediction formula based on residual tensile stress has been proposed, which makes the prediction accuracy higher than 96 %. This provides theoretical guidance and data support for the application of high-strength Al–Mg–Si–Cu alloys in lightweight automotive materials.

Uncontrolled forced oscillations can jeopardize the power system security. Most modeling and analysis methods for forced oscillations in previous publications were linearization methods such that some new nonlinear oscillation phenomenon can not be reproduced powerfully. Based on the considerations above, this paper hopes to provide clearer understandings and recognitions to forced oscillations by theoretically reveal the characteristics. First, a dynamic model of the current-controlled VSCs system based periodic forced oscillations is established to describe the relationships between system parameters and intrinsic quantities. Then, the multi-scale method is introduced to derive the mathematical expressions of approximate analytical solutions and relationship equation. Next, these characteristics, containing jumping phenomenon, frequency shift, doubling frequency response, and frequency coupling, are found and described by analyzing the mathematical expressions. Final, all the results are tested and verified on simulations and experiments.

In contrast to the intergenerational relations of families in the West, Chinese families emphasize mutual support and care among family members and consider parenting and filial duty a continuous process. Based on the typology of intergenerational relations in Western countries, this study constructs an analytical framework for Chinese families consisting of two dimensions: living arrangements and functional exchange. On this basis, it also proposes four potential types of intergenerational relationship: tight-knit, instrumental, independent, and parental support. Using a latent class analysis of nationally representative China Health and Retirement Longitudinal Study data helped us understand the different forms of intergenerational relationship and have a better understanding of their development trends. Several things can be learned from the findings. The significant share of the instrumental type and the emergence of the independent and parental support types indicate a change in intergenerational relationships in contemporary China. Although the traditional tight-knit type is no longer the dominant model, close intergenerational linkages are maintained through the instrumental and parental support types, and almost half of parents continue to have a close relationship with their children. This indicates that parenting and filial duty are preserved, reflecting the continuation of intergenerational relationships. The study also found that the type of intergenerational relationship is significantly influenced by the socioeconomic statuses of offspring and parents, indicating the reproduction of social inequality.

The low damping of a multi-terminal low-voltage direct current (MT-LVDC) system with the influence of negative impedance characteristic in DC network, can reduce the system stability. This study aims to find an additional control method to extend the system stable operating region on the premise of not changing the local control system of each converter and not affecting the accurate tracking of each converter’s power command under their normal dispatching, thereby significantly extending the stable operating region of a MT-LVDC system by small damping powers, and ensuring the stable DC voltage when operating point changes. First, an additional control method based on feedback linearization is proposed. Then an analytical expression of damping powers required to realize additional control is built, and a method to obtain the overall stable operating region is established. Furthermore, a multi-objective optimization model for additional control is proposed, and the optimized additional controller is obtained using Pareto front solution. The proposed method is experimentally verified to be able to provide an effective method to improve the system stability with simple control structure and low complexity, which can be conveniently implemented in the MT-LVDC system.

The Coronavirus (COVID-19) pandemic outbreak has significantly impacted the airline industry worldwide. However, limited studies have systematically investigated the airlines' responses and customer satisfaction in the aviation industry during the COVID-19 pandemic. The present study attempts to address this knowledge gap.

Due to the increases of renewable energy penetration and share of power electronic devices in the power system, Grid-forming (GFM) control methods have become one of the most important technology for the power systems with a high proportion of new energy resources. To improve the control performance of the VSC (Voltage Source Converter), a novel GFM control method based on negative imaginary theory is proposed in this paper. Firstly, the typical structure of distributed energy system is analyzed. Then, the negative imaginary characteristic of VSC’s mathematical model is proved and a negative imaginary controller (NIC) is designed. Finally, the effectiveness and feasibility of the proposed control method are verified by simulation results through MATLAB/Simulink.

Electric energy is the most commonly used energy in people’s daily life. In the process of use, how to improve the utilization rate of resources, so as to achieve the purpose of energy saving and environmental protection of power resources is a very significant work. The power grid is crucial in the transmission of electricity, and the energy consumption of substations is a major factor affecting the operation cost. Therefore, it is a key condition to ensure the stable operation of the power grid to scientifically calculate its energy consumption and formulate appropriate energy-saving measures. After consulting a large number of relevant documents and data, it has been found that many researchers have provided new ideas for the calculation of energy consumption and the study of energy-saving measures in substations. This article was adding its own understanding and taking it as the direction and basis. In the introduction, the research significance of substation energy consumption calculation was introduced, and then the academic research and analysis were carried out on the two key sentences of substation energy consumption calculation and analysis and the research of multi-objective artificial bee colony (ABC) algorithm in substation. In the method part, a constructive algorithm theory was proposed, and the application of the algorithm in substation energy consumption was proposed to provide a theoretical basis for the energy consumption calculation and energy conservation measures research of substations based on multi-objective ABC algorithm. At the end of the article, a simulation comparison experiment was carried out and the experiment was summarized and discussed. Firstly, the performance of the two algorithms was analyzed. Then, through the first selection of power plant T and Y, it was concluded that the resistivity of the cable in the distribution room in power plant Y was much higher than the average value based on the experimental results. Therefore, it was taken as the sample subject of the following experiments and analyzed again. For the second time, the analysis of district power plant Y showed that through simple calculation, the average energy efficiency difference of the distribution room before and after use was 3.1. Finally, it was analyzed that the ABC algorithm could not only improve the energy efficiency of the distribution room in the power plant, but also improve the effective efficiency of its power station. It shows that this kind of algorithm is effective and worthy of further study.

The problem of locating and evaluating microcracks in plates simultaneously was investigated using the nonlinear Lamb wave-mixing technique and Lamb transformer (LT) network in this work. The analyses of the nonlinear effects induced by the interaction of Lamb waves and microcracks with different locations, directions, and lengths were performed using the finite-element simulation. During the analysis part, the stacked spectrum map was introduced to analyze and reveal the influence of these three factors on the spectrum of the signal received by the sensor array. In the learning stage, to further identify the relationships between the microcrack features and the stacked spectrum map, the LT network using the stacked spectrum map and transformer encoder unit was provided for the training and conducted for further prediction of the microcrack with a well-trained model. The training and prediction results show that the average correct rate obtained in the validation set is 98.72% and the generated model also performs well on the test set, achieving an accuracy of 99%. This outcome demonstrates that the proposed LT network can be employed to identify the complex connections between the spectrum of the sensor array and microcracks and to realize the simultaneous localization and evaluation of microcracks. In summary, the LT network together with the stacked spectrum map presented in this work provides a novel baseline-free method for the localization and evaluation of microcracks and will further advance the application of Lamb wave technique and deep learning methods in microcrack detection.

White Etching Layer (WEL) and Brown Etching Layer (BEL) always form on the surface of rails and bearings subjected to rolling cyclic contact stress. Because of the different properties between WEL/BEL and matrix, the cracks initiate and propagate easily, leading to failure ultimately. The WEL and BEL found on pearlite rail, have been widely investigated, but WEL and BEL on bainite rail and martensite bearing have not been further studied. Especially the BEL on martensite bearing raceways has rarely been reported. This study investigates the features of WEL and BEL found on martensite bearing raceway. The BEL locates in the middle of WEL and matrix, but its hardness values are the highest, which is different from the general results reported: WEL > BEL > matrix. The WEL is mainly consisted of austenite with coarse grains, ferrite and retained tempered martensite. The mainly composition of BEL is quenched martensite. Thermal effect is the main formation mechanism of the WEL and BEL in this study. BEL forms because the surface temperature exceeds Acmpoint, and then rapidly decreases. The formation of WEL may originate from two processes: (1) The austenitizing and slowly cooling process again of BEL; (2) The austenitizing and slowly cooling process of the matrix. WEL and BEL forming processes are closely related to the diffusion and redistribution of carbon. The contributory heat conduction and diffusion mechanism in the confined spaces of grease lubricated bearings have been also discussed in this study.

The chemical industry is a major carbon emitter in China and must be focused on for China to achieve its goal of carbon neutralization. Carbon dioxide (CO2) high-temperature electrolysis based on solid oxide electrolysis cells (SOECs) is an important technology to achieve China’s carbon emission reduction, peak carbon emission, and carbon neutralization goals. Moreover, this technology can realize the recycling utilization of CO2and thereby contribute to considerable environmental benefits and potential economic benefits. Thus far, a great deal of progress has been made in CO2high-temperature electrolysis technology at the laboratory stage and pilot stage, although the large-scale industrial application of this technology still requires further development. This review focuses on recent progress in state-of-the-art cell materials for high-temperature CO2electrolysis, discusses the future research directions of SOEC technologies, and proposes possible SOEC-coupled chemical industry carbon neutralization solutions.

The evolutionary transition from self-incompatible distyly to self-compatible homostyly frequently occurs in heterostylous taxa. Although the inheritance of distyly and homostyly has been deeply studied, our understanding on modifications of the classical simple Mendelian model is still lacking. Primula forbesii, a biennial herb native to southwest China, is a typical distylous species, but after about 20 years of cultivation with open pollination, self-compatible homostyly appeared, providing ideal material for the study of the inheritance of distyly and homostyly. In this study, exogenous homobrassinolide was used to break the heteromorphic incompatibility of P. forbesii. Furthermore, we performed artificial pollination and open-pollination experiments to observe the distribution of floral morphs in progeny produced by different crosses. The viability of seeds from self-pollination was always the lowest among all crosses, and the homozygous S-morph plants (S/S) occurred in artificial pollination experiments but may experience viability selection. The distyly of P. forbesiiis governed by a single S-locus, with S-morph dominant hemizygotes (S/−) and L-morph recessive homozygotes (−/−). Homostylous plants have a genotype similar to L-morph plants, and homostyly may be caused by one or more unlinked modifier genes outside the S-locus. Open pollinations confirm that autonomous self-pollination occurs frequently in L-morphs and homostylous plants. This study deepens the understanding of the inheritance of distyly and details a case of homostyly that likely originated from one or more modifier genes.

BackgroundThe pathogenic mechanism of brain arteriovenous malformation (bAVM) is poorly understood. A growing body of evidence indicates that genetic factors play crucial roles in bAVM. This study examined genetic variants associated with bAVM through quantitative synthesis and qualitative description of literature.MethodsFive databases were searched to gather potentially relevant articles published up to January 2022. STATA 14.0 software was used for statistical analyses. Pooled odds ratios and 95% confidence intervals were calculated with random effect models, and heterogeneity was assessed using the Cochran Q test and quantified with the I2test. Sensitivity and publication bias were analyzed to test the robustness of the associations. Variants identified in only one study or with great heterogeneity were not suitable for pooling association analysis, and therefore a qualitative systematic review was performed.ResultsIn total, 30 papers were included in a systematic review involving 4709 cases and 7832 controls, where 17 papers were in a meta-analysis. A suggested association of bAVM was observed with ACVRL1rs2071219 in the additive model and CDKN2B-AS1rs1333040 in the recessive and additive models. Other variants of genes that could not be analyzed were summarized by qualitative description. These genes were mostly involved in bone morphogenic protein/transforming growth factor beta (BMP/TGF-β), vascular endothelial growth factor/vascular endothelial growth factor receptor (VEGF/VEGFR), and RAS-mitogen activated protein kinase (MAPK) signaling and inflammation.ConclusionsAccording to our meta-analysis, ACVRL1rs2071219 and CDKN2B-AS1rs1333040 were potentially associated with bAVM. Multiple pathological signaling pathways could affect disease development. Future studies should aim to determine the interaction of candidate genes with environmental risk factors and to elucidate detailed mechanisms of action of variants and genes.1

Background: Knobs-into-holes (KiH) technology has been widely used in asymmetric bispecific antibody (bsAb) construction to promote heavy chain heterodimerization. However, despite the great improvement of heterodimer formation by this strategy, homodimers (especially the holehole homodimer) can still be generated at low levels. Consequently, hole-hole homodimer is a common byproduct associated with the production of KiH bsAbs. In addition, previous studies showed that hole-hole homodimer exists as two different isoforms. As the major difference between these two isoforms lies in the Fc region, we speculated that Protein A media, which bind IgG Fc region with high affinity, and CaptureSelect FcXP, a CH3 domain-specific affinity resin, may provide certain resolution between these two conformational isoforms. Objective: The objective of this study was to study the capability of Protein A and CaptureSelect FcXP affinity resins in differentiating hole-hole homodimer isoforms. Methods: The hole-hole homodimer was produced in CHO cells by expressing the hole half-antibody. The homodimer, along with the half-antibody was initially captured by Protein A chromatography and was then further purified by size-exclusion chromatography (SEC), which separated the homodimer from the unpaired half-antibody. The purified hole-hole homodimer was analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and analytical hydrophobic interaction chromatography (HIC). The purified hole-hole homodimer was separately processed by columns packed with Protein A and CaptureSelect FcXP resins. The purified hole-hole homodimer was also analyzed by Protein A-high-performance liquid chromatography (HPLC). Results: SDS-PAGE analysis and analytical HIC study confirmed that hole-hole homodimer exists as two conformational isoforms. When the hole-hole homodimer was processed by Protein A and CaptureSelect FcXP chromatography, the elution profiles contained two peaks, indicating that both affinity resins possess the capability of differentiating hole-hole homodimer isoforms. Conclusion: Our data suggest that Protein A and CaptureSelect FcXP affinity resins both possess the capability of differentiating hole-hole homodimer isoforms and, therefore, can be used for monitoring isoform conversion under various conditions.

The switching-table-based direct torque control (ST-DTC) has the merits of simple structure, easy implementation, and fast response, but suffers from large torque ripples. Previous literature, i.e., the classical DTC, can achieve torque ripple reduction in the high-speed region but has a limited capability for torque ripple reduction in the low-speed region. In this paper, the issue of torque ripple reduction in the full-speed region, i.e., both the low-speed and high-speed regions, is addressed. The effects of each group in all possible six groups of virtual voltage vectors (VVs) on torque variation are firstly investigated. Then, a multiple VV DTC based on only three groups of VVs is proposed and the corresponding optimal selections of three VV groups and level of torque regulator are presented. The proposed DTC not only can effectively reduce torque ripples in the full speed region, but also is simple and easy to implement. The superiority of the proposed DTC with optimal selections of VVs and level of torque regulator are verified by experimental results.

• Grinding treatment decreased sensitivity and risk of SCC in scratched area. • Some residual slip steps remain in scratched area after grinding. • Enhanced grinding performance can be attained using high-grit abrasive paper. • Deep scratches are hazardous even after grinding. Alloy 690TT tube samples with different scratch depths were repaired by grinding treatments using abrasive papers of two different particle sizes. The microstructure and stress corrosion cracking (SCC) behavior were studied in detail. During grinding, the plastic accumulation zone vulnerable to SCC was removed. Meanwhile, some residual slip steps remained in the scratched area. Corrosion tests lasting 1000, 2000, 3000, and 4000 h show that the sensitivity and risk of SCC in the scratched area are decreased by grinding. Treatment using abrasive particles of a smaller size is more effective. Nevertheless, deep scratches remained hazardous even after the grinding. [ABSTRACT FROM AUTHOR]

Grid-forming (GFM) converters can provide inertia support for power grids through control technology, stabilize voltage and frequency, and improve system stability, unlike traditional grid-following (GFL) converters. Therefore, in future “double high” power systems, research on the control technology of GFM converters will become an urgent demand. In this paper, we first introduce the basic principle of GFM control and then present five currently used control strategies for GFM converters: droop control, power synchronization control (PSC), virtual synchronous machine control (VSM), direct power control (DPC), and virtual oscillator control (VOC). These five strategies can independently establish voltage phasors to provide inertia to the system. Among these, droop control is the most widely used strategy. PSC and VSM are strategies that simulate the mechanical characteristics of synchronous generators; thus, they are more accurate than droop control. DPC regulates the active power and reactive power directly, with no inner current controller, and VOC is a novel method under study using an oscillator circuit to realize synchronization. Finally, we highlight key technologies and research directions to be addressed in the future.

This study investigates the orbital Target-Attacker-Defender (TAD) game problem in the context of space missions. In this game, the Attacker and the Defender compete for a Target that is unable to maneuver due to its original mission constraints. This paper establishes three TAD game models based on the thrust output capabilities: unconstrained thrust output, thrust constrained by an upper bound, and fixed thrust magnitude. These models are then solved using differential game theory to obtain Nash equilibrium solutions for the game problems, and the correctness and effectiveness of the solution methods are verified through simulations. Furthermore, an analysis of the winning mechanisms of the game is conducted, identifying key factors that influence the game’s outcomes, including weight coefficients in payoffs, the maximum thrust acceleration limit, and the initial game state. Considering the unique characteristics of space missions, a specific focus is given to the analysis of the Defender’s initial states in the hovering formation and in-plane circling formation, revealing overall success patterns for defense strategies from these two formations. In summary, this study provides valuable insights into the control strategies and winning mechanisms of orbital TAD games, deepening our understanding of these games and offering practical guidance to improve success rates in real-world scenarios.

This paper describes the results of a performance review of a 10 kW/100 kWh commercial VFB system that has been commissioned and in operation for more than a decade. The evaluation focused on the system efficiencies, usable capacity, electrolyte stability and stack degradation. The analysis shows that the system has stable performance and very little capacity loss for over a decade since commissioning. Only very recently, a slight decrease in system discharge capacity (approximately 5 %) was observed and indicated by changes in the electrolyte valence state. The capacity was restored to the original level after conducting a rebalancing procedure. This demonstrates the advantage that the flow batteries employing vanadium chemistry have a very long cycle life. Furthermore, electrochemical impedance spectroscopy analysis was conducted on two of the battery stacks. Some degradation was observed in one of the stacks reflected by the increased charge transfer resistance. To further investigate the ageing of the stacks, reverse polarity tests were carried out. It is found that reversing the polarity both hydraulically and electrically can restore the stack performance. The study shows that the VFB is a reliable technology for large-scale energy storage applications.

There has been an increase in the use of molecular probe diagnostic techniques for lung cancer, and magnetic resonance imaging (MRI) offers specific advantages for diagnosing pulmonary carcinoma. Furthermore, advancements in near-infrared II (NIR-II) fluorescence have provided a new method for precise intraoperative tumor resection. However, few probes combine preoperative diagnosis with intraoperative imaging. This study aims to fill this research void by employing a dual-modal probe that targets the epidermal growth factor receptor for MR and NIR-II imaging, enabling the preoperative diagnosis of lung cancer using MRI and precise intraoperative tumor localization using NIR-II with a single probe. The imaging effects and targeting ability of the probe were confirmed in cell lines, mouse models, and clinical samples. The MR signal decreased within 24 h in the patient-derived xenograft mouse model. The average signal-to-background ratio of NIR-II reached 3.98 ± 0.27. The clinical sample also showed a decrease in the T2 signal using MRI, and the NIR-II optical signal-to-background ratio was 3.29. It is expected that this probe can improve the diagnostic rate of lung cancer using MRI and enable precise intraoperative tumor resection using NIR-II.

Anti-Freezing Asphalt Pavement (AFAP) has good snow-melting performance and is used widely in many countries around the world. The objective of this study was to analyze AFAP’s long-term performance and predict its snow-melting ability. Two types of anti-freezing stone matrix asphalt (SMA) mixtures (SMA-13 with Iceguard and SMA-13 with Mafilon) were prepared with the Marshall method. Water stability, high-temperature stability, low-temperature crack resistance, and freeze-thaw split tests were conducted to evaluate mixtures’ performance. Meanwhile, the effect of anti-freezing filler, asphalt content, and soaking temperature on the salt dissolution of anti-freezing asphalt mixtures was analyzed, and the snow-melting ability of AFAP was predicted based on the Back Propagation (BP) neural network. The results illustrated that water stability of anti-icing asphalt mixture reduced, and the dynamic stability after short-term aging was improved. The tensile strain and tensile strength ratio of the anti-icing asphalt mixture reduced after long-term aging and soaking in water. In addition, the salt dissolution rate increased with the increase of anti-freezing filler content and the decrease of asphalt content. The research conducted suggests that the BP Neural Network can be utilized to predict the snow-melting ability of the anti-freezing asphalt mixture, and the regression coefficient of the predicted and measured salt dissolution was higher.

Enzyme immobilization has attracted great attention for improving the performance of enzymes in industrial applications. This work was designed to create a new support for Candida rugosalipase (CRL) immobilization. A porous poly(vinyl acetate–divinyl benzene) microsphere coated by a zwitterionic polymer, poly(maleic anhydride-alt-1-octadecene) and N,N-dimethylethylenediamine derivative, was developed for CRL immobilization viahydrophobic binding. The catalytic activity, reaction kinetics, stabilities and reusability of the immobilized CRL were investigated. It demonstrated the success of the zwitterionic polymer coating and subsequent CRL immobilization on the porous microsphere. The immobilized lipase (p2-MS-CRL) reached 27.6 mg·g−1dry carrier and displayed a specific activity 1.5 times higher than free CRL. The increase of Vmaxand decrease of Kmwere also observed, indicating the improvement of catalytic activity and enzyme-substrate affinity of the immobilized lipase. Besides, p2-MS-CRL exhibited significantly enhanced thermal stability and pH tolerance. The improved performance was considered due to the interfacial activation regulated by the hydrophobic interaction and stabilization effect arisen by the zwitterionic polymer coating. This study has thus proved the advantages of the zwitterionic polymer-coated porous carrier for lipase immobilization and its potential for further development in various enzyme immobilizations.

Nd0.8Sr1.2CoO4±δ(NSC214)/Nd0.5Sr0.5CoO3-δ(NSC113) multilayered heterostructured thin film cathodes of SOFCs exhibit ∼ 20 times difference in polarization resistance and catalytic activity toward oxygen reduction reaction (ORR), which are synthesized by pulsed laser deposition under different temperatures. The thin-films grown at 650 °C possess consistent crystal orientation, while those grown at 500 °C have different crystal orientations between NSC113and NSC214layers. As observed, they show ∼102times and ∼101times, respectively, higher ORR performance than a single-phase NSC113thin-film electrode, as characterized by constructing full cell operated at intermediate-temperature. The origin of such performance differences is analyzed on the basis of crystal orientation by HRXRD, HRTEM, HAADF-STEM, TOF-SIMS, and DFT calculation, and the results indicate that the increased crystal orientations can significantly weaken the positive effects of heterointerface. This observation is attributed to the formation of excessive grain boundaries, which leads to increased formation energy of oxygen vacancy and limited oxygen transportation. These results highlight that the precise control of crystal orientation can make full use of heterostructure to enhance the ORR performance of electrochemical devices.

Owing to their high efficiency and low emission, solid oxide fuel cells (SOFCs) are promising devices that directly convert various hydrocarbon fuels into electric power and chemical materials through catalytic oxidation. However, the broad and large-scale implementation of the technology is hindered by anode coking, which distinctively weakens electrochemical catalytic oxidation in anodes and causes serious passivation issues and even the failure of SOFC systems. Since surface coke can occur in a few seconds and within several nanometers of an anode surface, advanced in situcharacterization methods and theoretical simulations are crucial to provide valuable insight into the evolution of surface structures and compositions in real time and at high spatial and temporal resolutions in this dynamic process. In this review, we highlighted the recent progress in the fundamental understanding of anode coking and considered the elementary steps, thermodynamics, kinetics and susceptible sites of coking. We also reviewed representative surface engineering approaches that enhance electrode durability under carbon-related atmospheres. Furthermore, the knowledge and methodology introduced in this paper are applicable to industrial operations, which often encounter carbon poisoning issues, including steam reforming of natural gas, styrene production from ethylbenzene, cracking reaction of heavy oil fractions, and solid acid alkylation.

Perovskite-based La0.6Sr0.4CoO3-d (LSC) is considered as one of the most promising electrode materials for solid oxide fuel cells (SOFCs). The broad application is, however hindered by its insufficient stability and reactivity at operating conditions. In this study, extrinsic Fe3+ decoration was applied to enhance the electrochemical performance of LSC thin-film electrodes by nearly 4 times. Time-of-flight secondary ion mass spectrometry indicated that the extrinsic Fe3+ can incorporate into LSC lattice and form a thermodynamically preferred (La, Sr)x(Co, Fe)yO3-d transition phase in the near surface region, thus improving its chemical stability against Sr segregation. X-ray photoelectron spectroscopy suggested the incorporation of Fe can lead to a ~0.2 eV downshift in LSC valance band and facilitate the formation of oxygen vacancies, thus enhancing electrode reactivity. These results can help us understand the mechanism of surface modification, and provide guidance for the rational design of more applicable SOFC electrode materials with higher reactivity and durability.

Abstract A ductility-dip-cracking (DDC)-concentrated zone (DCZ) in a width of about 3 mm was observed adjacent to the AISI 316 L/52 Mw fusion boundary (FB) in 52 Mw. The morphology, microstructure, mechanical and thermal properties and corrosion behavior in simulated primary water of DDC/DCZ were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), 3D X-ray tomography (XRT), 3D atom probe (3DAP), slow strain rate tensile (SSRT) testing and thermal dilatometry. The results indicate that DDCs are random-shaped and disc-like cavities with corrugated structure of inner surface and are parallel in groups along straight high-angle boundaries of columnar grains, ranging from micrometers to millimeters in size. Large-size M 23 C 6 carbides dominate on the grain boundaries rather than M C (M =Nb, Ti), and thus the bonding effect of carbides is absent for the straight grain boundaries. The impurity segregation of O is confirmed for the inner surfaces of DDC. The oxide film formed on the inner surface of DDC (about 50 nm) is approximately twice as thick as that on the matrix (about 25 nm) in simulated primary water. The yield strength, tensile strength and elongation to fracture of 52 Mw-DCZ (400 MPa, 450 MPa and 20 %, respectively) are lower than those of 52 Mw-MZ (460 MPa, 550 MPa and 28 %, respectively). The intrinsic high-restraint weld structure, the additional stress/strain caused by the thermal expansion difference between AISI 316 L and 52 Mw as well as the detrimental carbide precipitation and the resulting grain boundary structure all add up to cause the occurrence of DCZ in the dissimilar metal weld. [ABSTRACT FROM AUTHOR]

In this big data era, interpretable machine learning models are strongly demanded for the comprehensive analytics of large-scale multiclass data. Characterizing all features from such data is a key but challenging step to understand the complexity. However, existing feature selection methods do not meet this need. In this paper, to address this problem, we propose a Bayesian multiclass nonnegative matrix factorization (MC-NMF) model with structured sparsity that is able to discover ubiquitous and class-specific features. Variational update rules were derived for efficient decomposition. In order to relieve the need of model selection and stably describe feature patterns, we further propose MC-NMF with stability selection, an ensemble method that collectively detects feature patterns from many runs of MC-NMF using different hyperparameter values and training subsets. We assessed our models on both simulated count data and multitumor ribonucleic acid-seq data. The experiments revealed that our models were able to recover predefined feature patterns from the simulated data and identify biologically meaningful patterns from the pan-cancer data.

It is well known that defect chemistry plays a vital role in determining the electronic structure, ionic conductivity, and catalytic activity of metal oxides, as demonstrated in perovskite-based oxides to achieve desired functionalities. In this work, we explored the possibility of tuning the defect chemistry and hydrogen oxidation reaction (HOR) activity of Nd2NiO4+δmodel thin films by controlling the lattice strain. Highly textured Nd2NiO4+δthin films with different strain states were prepared on (110)- and (100)-oriented single-crystal yttrium-stabilized zirconium (YSZ) substrates using pulsed laser deposition. Electrochemical impedance spectroscopy results indicated that the NNO(100) film on the YSZ(110) substrate with larger tensile strain in the a–bplane and compressive strain along the caxis exhibited higher HOR activity than the NNO(110) film on the YSZ(100) substrate at 500–600 °C. The enhancement in HOR activity is attributed to the strain-induced difference in the oxygen defect concentration, as confirmed by high-resolution X-ray diffraction analysis. We believe that the correlation among the strain state, defect chemistry, and catalytic properties is helpful for rational design of more efficient electrode materials.

Electrode materials with high activity and good stability are essential for commercialization of energy conversion systems such as solid oxide fuel cells or electrolysis cells at the intermediate temperature. Modifying the existing perovskite-based electrode surface to form a heterostructure has been widely applied for the rational design of novel electrodes with high performance. Despite many successful developments in enhancing electrode performance by surface modification, some controversial results are also reported in the literature and the mechanisms are still not well understood. In this work, the mechanism of how surface modification impacts the oxygen reduction reaction (ORR) activity and stability of perovskite-based oxides was investigated. We took La0.6Sr0.4Co0.2Fe0.8O3(LSCF) as the thin-film model system and modified its surface with additive PrxCe1–xO2layers of different thicknesses. We found a strong correlation between surface oxygen defects and the ORR activity of the heterostructure. By inducing higher oxygen vacancy concentration compared to bare LSCF, PrO2coating is proved to greatly facilitate the rate of oxygen dissociation, thus significantly enhancing the ORR activity. Because of low oxygen vacancy density introduced by Pr0.2Ce0.8O2and CeO2coating, on the one hand, it does not boost the rate of ORR but successfully suppresses surface Sr segregation, leading to an enhanced durability. Our findings demonstrate the vital role of surface oxygen defects and provide important insights for the rational design of high-performance electrode materials through surface defect engineering.

In this study, we present a swing-arm type membrane-type acoustic metamaterial (MAM) with multi-state anti-resonances. The designed structure is lightweight and can achieve excellent sound insulation in a wide frequency range of 100–1000 Hz. Through the analysis of sound transmission loss and anti-resonance mode, the sound insulation principle of MAM is obtained. Besides, the orthogonal experiment presents the order of the main factors affecting the sound insulation performance. Based on the relative bandwidth as the classification criterion, k-nearest neighbor with analytic hierarchy process and K-Fold cross-validation is utilized to predict different levels of sound insulation.

Realization problems, including the minimum realization of Boolean control networks (BCNs), are investigated by the vertex partition method. A general definition of the realization for BCNs that does not involve any subspaces is proposed. For the new and existing realization definitions, by a common concolorous perfect vertex partition (CCP-VP) of vertex-colored state transition graphs, an equivalence relation and a quotient mapping are defined, which induce a quotient system, i.e., the realization of original BCNs. In addition, if the CCP-VP is an equal partition, a realization induced by a γ-friendly controlled invariant regular subspace is constructed. Finally, an algorithm is designed to construct the minimum realization of BCNs for different realization definitions, and three examples are given to illustrate the obtained results.

Solid-oxide fuel cells (SOFCs) are clean and highly efficient electrochemical energy conversion devices and in this study, novel nanolayer-structured cathodes with Nd0.5Sr0.5CoO3-δ/Nd0.8Sr1.2CoO4±δheterointerfaces for intermediate-temperature SOFCs are developed in which significantly enhanced oxygen reduction reaction (ORR) kinetics are obtained by increasing the interface layers. The electrical surface exchange coefficient (kq) of the resulting sample (NSC214/113-17L) with multilayered heterointerfaces reached 2.917 × 10−7cm s−1at 10% oxygen pressure under 500 °C, and was 102–103times higher than those of the single-phase samples, including NSC113(1.335 ×10−9cm s−1) and NSC214(1.057 ×10−9cm s−1). Heterointerface characterizations were conducted using Time of Flight Secondary Ion Mass Spectrometry (ToF-SIMS), Scanning Transmission Electron Microscopy (STEM), Energy Dispersive Spectrometer (EDS) and Electron Energy Loss Spectroscopy (EELS) and revealed an enrichment of Sr and a decrease in the valence state of cobalt at the interfacial regions. These two factors together induced the generation of oxygen vacancies VO∙∙and further facilitated ion transportation, as confirmed by density functional theory (DFT) simulations. Our findings provide a novel heterointerface with high activity and offer specific evidence to elucidate the origin of the resulting enhanced ORR kinetics.

•A gain scheduling approach developed to control the flow rate for VRB system.•Electrolyte flow rate control based on the inlet and outlet OCV measurements.•Simulation studies presented to illustrate the control performance.

CO2conversion to produce useful fuels/chemicals is a promising route for reducing CO2emission as well as for exploring the promising energy storage method. To facilitate the research and development of CO2conversion, this paper provides a comprehensive overview of CO2conversions using advanced materials/nanomaterials and technologies for the production of useful fuels/chemicals. The molecular structure, thermodynamics and kinetics of CO2are reviewed for the understanding of fundamentals and explaining why C=O double bonds are difficult to break. The mechanisms and features of various conversion technologies are summarized and classified into enzymatic, mineralization, photochemical/photo-electrochemical, thermochemical as well as electrochemical processes. In particular, by comparing electrochemical conversion technologies at low and high temperatures, CO2conversion at intermediate temperatures is emphasized. Furthermore, the economic feasibility for CO2utilization is analyzed with cases for the production of various chemicals/fuels. The technical and application challenges of CO2conversion into useful fuels/chemicals are also summarized, composing mainly of: insufficient fundamental understanding, low product selectivity, as well as low efficiency and stability. To overcome these challenges, future research directions are proposed in this review.

This study proposes an innovative data-driven battery modelling algorithm for vanadium redox flow battery (VRB) in power systems. Unlike the existing battery modelling methods, the proposed algorithm employed the simple but computationally efficient one dimensional convolutional neural network (1D-CNN) technique to learn the nonlinear relationships between VRB current, flow rate, state-of-charge (SOC), and voltage. Compared to the two dimensional CNN, which is widely used in lithium-ion battery modelling and monitoring studies, 1D-CNN eliminates the tedious data re-structuring process and provides better accuracy. Thus, it is more suitable for battery modelling based on one dimensional time series data. Furthermore, 1D-CNN is independent of battery model parameters, allowing it to provide superior modelling performance over the existing electrochemical principle-based and equivalent circuit-based modelling methods that rely on the knowledge of accurate battery model. The validity of the proposed 1D-CNN is verified by experiments.