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Science China(Information Sciences) 2022年第10期65卷 211-224页

作者： xiaozhou lü Chao YUAN Weimin BAO Guanghui BAI Fancheng MENG School of Aerospace Science and Technology Xidian University Science and Technology on Space Physics laboratory College of Materials Science and Engineering Chongqing University of Technology

In this paper, a flexible skin inspired by the sudoriferous gland structure of human skin is developed for ultra-thermal protection of hypersonic morphing vehicles. The effect of different coolants and cooling flow rates on the cooling performance of the leading edge is studied using finite element analysis.A wind tunnel experiment is conducted at high temperatures with the heat flux Q = 700 k W/m2, and the results indicate the following:(1) the flexible skin can effectively reduce the surface temperature of hypersonic vehicles;(2) when using liquid water instead of argon as the cooling medium, the cooling efficiency of flexible skin performs better;(3) when liquid water is used as the cooling medium, the cooling effect peaks at a flow rate of 0.01 m/s, and further increasing the flow rate will not benefit cooling efficiency significantly;(4) the flexible skin can withstand extreme thermal environments, demonstrating its feasibility in applications of over-limit thermal protection for hypersonic morphing vehicles. This study aims at optimizing the cooling performance of the flexible skin for ultra-thermal protection. The proposed skin can overcome the heat-resistance limit of flexible materials with morphing properties, laying a theoretical and experimental foundation for its future applications in hypersonic morphing vehicles.

关键词： hypersonic vehicle flexible skin ultra-thermal protection micro-channel transpiration cooling

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机动车行人保护发射装置研究

汽车工程 2022年第2期44卷 233-238,271页

作者：查宏民吕晓洲中汽研汽车工业工程(天津)有限公司天津300300

本文以行人保护测试系统发射装置为研究对象,采用高速液压弹射控制技术,分别阐述了发射装置的构成、高速液压缸的结构设计、高速液压发射的控制原理及电气控制系统。最后通过对各种冲击模型的实际测试进行了验证,结果表明:其发射速度稳... 详细信息

本文以行人保护测试系统发射装置为研究对象,采用高速液压弹射控制技术,分别阐述了发射装置的构成、高速液压缸的结构设计、高速液压发射的控制原理及电气控制系统。最后通过对各种冲击模型的实际测试进行了验证,结果表明:其发射速度稳定、准确、可靠,达到了试验要求。该装置可缓解目前国内行人保护测试设备主要依赖进口的局面,形成了采用高速液压缸进行行人保护试验测试设备的专有技术。

关键词：行人保护高速液压缸弹射控制高频响伺服阀高速液压伺服控制

Predicting moisture condensation risk on the radiant cooling floor of an office using integration of a genetic algorithm-back-propagation neural network with sensitivity analysis

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Energy and Built Environment 2024年第1期5卷 110-129页

作者： Meng Su Jiying liu Moon Keun Kim xiaozhou Wu School of Thermal Engineering Shandong Jianzhu UniversityJinan 250101China Department of Civil Engineering and Energy Technology Oslo Metropolitan UniversityOslo N-0130Norway School of Civil Engineering Dalian University of TechnologyDalianChina

Pre-dehumidification time(τ_(pre))and pre-dehumidification energy consumption(E_(pre))play important roles in preventing the condensation of moisture on the floors of rooms that use a radiant floor cooling(RFC)***,there are few theoretical or experimental studies that focus on these two important *** this study,an artificial neural network(ANN)was used to predict condensation risk for the integration of RFC systems with mixed ventilation(MV),stratum ventilation(SV),and displacement ventilation(DV)systems.A genetic algorithm-back-propagation(GA-BP)neural network model was established to predict τ_(pre) and E_(pre).Both training data and validation data were obtained from tests in a computational fluid dynamics(CFD)*** results show that the established GA-BP model can predict τ_(pre) and E_(pre) *** coefficient of determination(R^(2))of τ_(pre) and of E_(pre) were,respectively,0.973 and *** an RFC system integrated with an MV,SV,or DV system,the lowest values of τ_(pre) and E_(pre) were with the DV system,23.1 s and 0.237 kWh,respectively,for a 67.5 m^(3) ***,the best pre-dehumidification effect was with integration of the DV and RFC *** study showed that an ANN-based method can be used for predictive control for condensation prevention in RFC *** also provides a novel and effective method by which to assess the pre-dehumidification control of radiant floor surfaces.

关键词： Condensation prevention Radiant floor cooling Ventilation system genetic algorithm BP neural network

Simulation of Corrosion-Induced Cracking of Reinforced Concrete Based on Fracture Phase Field Method

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Computer Modeling in Engineering & Sciences 2024年第3期138卷 2257-2276页

作者： xiaozhou Xia Changsheng Qin Guangda lu Xin Gu Qing Zhang College of Mechanics and Materials Hohai UniversityNanjing210098China State Key laboratory of Disaster Reduction in Civil Engineering&College of Civil Engineering Tongji UniversityShanghai200092China

Accurate simulation of the cracking process caused by rust expansion of reinforced concrete(RC)structures plays an intuitive role in revealing the corrosion-induced failure *** the quasi-brittle fracture of concrete,the fracture phase field driven by the compressive-shear term is constructed and added to the traditional brittle fracture phase field *** rationality of the proposed model is verified by a mixed fracture example under a shear displacement ***,the extended fracture phase model is applied to simulate the corrosion-induced cracking process of *** cracking patterns caused by non-uniform corrosion expansion are discussed for RC specimens with homogeneous macroscopically or heterogeneous with different polygonal aggregate distributions at the mesoscopic ***,the effects of the protective layer on the crack propagation trajectory and cracking resistance are investigated,illustrating that the cracking angle and cracking resistance increase with the increase of the protective layer thickness,consistent with the experimental ***,the corrosion-induced cracking process of concrete specimens with large and small spacing rebars is simulated,and the interaction of multiple corrosion cracking is easily influenced by the reinforcement spacing,which increases with the decrease of the steel bar *** conclusions play an important role in the design of engineering anti-corrosion *** fracture phase field model can provide strong support for the life assessment of RC structures.

关键词： Fracture phase field corrosion-induced cracking non-uniform corrosion expansion protective layer thickness reinforcement concrete

Byzantine-robust distributed support vector machine

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Science China Mathematics 2024年

作者： xiaozhou Wang Weidong liu Xiaojun Mao School of Statistics East China Normal University Key laboratory of Advanced Theory and Application in Statistics and Data Science (Ministry of Education) East China Normal University School of Mathematical Sciences Shanghai Jiao Tong University Key laboratory of Artificial Intelligence (Ministry of Education) Shanghai Jiao Tong University Key laboratory of Scientific and Engineering Computing (Ministry of Education) Shanghai Jiao Tong University

The development of information technology brings diversification of data sources and large-scale data sets and calls for the exploration of distributed learning algorithms. In distributed systems, some local machines may behave abnormally and send arbitrary information to the central machine(known as Byzantine failures), which can invalidate the distributed algorithms based on the assumption of faultless systems. This paper studies Byzantine-robust distributed algorithms for support vector machines(SVMs) in the context of binary classification. Despite a vast literature on Byzantine problems, much less is known about the theoretical properties of Byzantine-robust SVMs due to their unique challenges. In this paper, we propose two distributed gradient descent algorithms for SVMs. The median and trimmed mean operations in aggregation can effectively defend against Byzantine failures. Theoretically, we show the convergence of the proposed estimators and provide the statistical error rates. After a certain number of iterations, our estimators achieve near-optimal rates. Simulation studies and real data analysis are conducted to demonstrate the performance of the proposed Byzantine-robust distributed algorithms.

关键词： Keywords Byzantine robustness convergence distributed learning support vector machineMSC(2020) 62H30 68W15

Unveiling inverse vulcanized polymers as metal-free,visible-light-driven photocatalysts for cross-coupling reactions

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Chinese Chemical letters 2024年第4期35卷 142-146页

作者： lang Gao Cen Zhou Rui Wang Feng lan Bohang An xiaozhou Huang Xiao Zhang Fujian Key laboratory of Polymer Science Fujian Provincial Key Laboratory of Advanced Materials Oriented Chemical EngineeringCollege of Chemistry and Materials ScienceFujian Normal UniversityFuzhou 350007China Fujian Engineering and Research Center of New Chinese lacquer Materials College of Materials and Chemical EngineeringMinjiang UniversityFuzhou 350108China

Inverse vulcanized polymers(IVPs) that generated from elemental sulfur and smaller amounts of alkenes have found broad promising applications such as cathode materials for li-S batteries, dynamic and repairable materials, optics applications, and metal sorption. However, their exploration in organic synthesis is still unprecedented. Here we first report the application of inverse vulcanized polymers in catalysis for organic transformations. A biomass-derived inverse vulcanized polymer(IVP-EAE) is found to be capable of catalyzing cross-coupling reactions in a transition-metal-free fashion under visible *** method allows the direct C–H functionalization of pyrroles and N-arylacrylamides with(hetero)aryl halides, respectively, leading to the formation of two sets of structurally important scaffolds including pyrrole-containing biaryls and 3,3-disubstituted oxindoles with high selectivity. We anticipate this study will not only unveil the new potential of IVPs, but also offer a distinct type of catalysts for organic transformations.

关键词： Cross coupling Inverse vulcanized polymers Metal free Photocatalyst Visible light

Exploration on the Frontiers of Flexible and Deformable Cross-Domain Intelligent Flight

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Aerospace China 2021年第1期22卷 5-11页

作者： BAO Weimin lüxiaozhou BAI Guanghui lI Xiaoping lIU Yanmin BAI Bowen SHI Yaoguang School of Aerospace Science&Technology Xidian UniversityXi’an 710071 China Aerospace Science and Technology Corporation Beijing 100048 Science and Technology on Space Physics laboratory Beijing 100076

As human aeronautic and aerospace technology continues to prosper and the aerial flight space domain further expands,traditional fixed-shape air vehicles have been confronted with difficulties in satisfying complex missions in cross-domain *** to their flexible and deformable appearance,morphing air vehicles are expected to realize cross-domain intelligent flight,thus emerging as the most subversive strategic development trend and research focus in aeronautic and aerospace *** paper primarily reviews the research background and challenges of flexible and deformable cross-domain intelligent flight,proposing a corresponding research framework and mode as well as exploring the scientific issues and state-of-the-art solutions,where key research progress is *** explorations covered in this paper also provide ideas and directions for the study of deformable cross-domain intelligent flight,which has critical scientific significance in promoting the study itself.

关键词： cross-domain flight flexible intelligent deformable configuration

ROS Balance Autoregulating Core-Shell CeO_(2)@ZIF-8/Au Nanoplatform for Wound Repair

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Nano-Micro letters 2024年第8期16卷 341-361页

作者： Xi Zhou Quan Zhou Zhaozhi He Yi Xiao Yan liu Zhuohang Huang Yaoji Sun Jiawei Wang Zhengdong Zhao xiaozhou liu Bin Zhou lei Ren Yu Sun Zhiwei Chen Xingcai Zhang The Higher Educational Key laboratory for Biomedical Engineering of Fujian Province Research Center of Biomedical Engineering of XiamenDepartment of BiomaterialsCollege of MaterialsXiamen UniversityXiamen 361005People’s Republic of China Department of Electronic Science Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance ResearchSchool of Electronic Science and EngineeringXiamen UniversityXiamen 361005People’s Republic of China John A Paulson School of Engineering and Applied Sciences Harvard UniversityCambridgeMA 02138USA Department of Otorhinolaryngology Union Hospital of Tongji Medical CollegeHuazhong University of Science and TechnologyWuhan 430022People’s Republic of China NO.1 Middle School Affiliated to Central China Normal University Wuhan 430223People’s Republic of China

Reactive oxygen species(ROS)plays important roles in living *** ROS is a double-edged sword,which can eliminate drug-resistant bacteria,but excessive levels can cause oxidative damage to cells.A core–shell nanozyme,Ce O_(2)@ZIF-8/Au,has been crafted,spontaneously activating both ROS generating and scavenging functions,achieving the multifaceted functions of eliminating bacteria,reducing inflammation,and promoting wound *** Au Nanoparticles(NPs)on the shell exhibit high-efficiency peroxidase-like activity,producing ROS to kill ***,the encapsulation of Ce O_(2) core within ZIF-8 provides a seal for temporarily limiting the superoxide dismutase and catalase-like activities of Ce O_(2) ***,as the ZIF-8 structure decomposes in the acidic microenvironment,the Ce O_(2) core is gradually released,exerting its ROS scavenging activity to eliminate excess ROS produced by the Au *** two functions automatically and continuously regulate the balance of ROS levels,ultimately achieving the function of killing bacteria,reducing inflammation,and promoting wound *** innovative ROS spontaneous regulators hold immense potential for revolutionizing the field of antibacterial agents and therapies.

关键词： Metal-organic framework(MOF) Reactive oxygen species(ROS) Cerium dioxide Au nanoparticles Wound healing

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废锂离子电池碳热还原优先提锂工艺优化

化工进展 2024年第4期43卷 2174-2182页

作者：周铭贤叶小舟上海电气集团股份有限公司中央研究院上海200070

对废旧三元锂离子电池正极材料采用碳热还原-通二氧化碳水浸的工艺进行优先提锂。本文采用单一变量法探究焙烧过程中焙烧温度、焙烧时长、有效加碳量及水浸过程中水浸时长、水浸固液比、二氧化碳流量、逆流水洗级数等参数改变带来的金... 详细信息

对废旧三元锂离子电池正极材料采用碳热还原-通二氧化碳水浸的工艺进行优先提锂。本文采用单一变量法探究焙烧过程中焙烧温度、焙烧时长、有效加碳量及水浸过程中水浸时长、水浸固液比、二氧化碳流量、逆流水洗级数等参数改变带来的金属元素浸出率的影响。在焙烧温度700℃、焙烧时长120min、有效加碳量(75.56%含碳量的炭粉)为14%(质量分数)、液固比10ml/g、水浸时长180min、二氧化碳通入量100ml/min、三级逆流水洗的最佳条件下,可以达到锂的浸出率为96.31%,钴、镍、锰金属的浸出率均低于0.1%。同时考察了该工艺对于不同型号的废三元锂离子电池回收的适用性,发现提锂效果均在90%以上,具有良好的原料适应性。此外,通过X射线衍射、透射电子显微镜、扫描电子显微镜探究碳热还原前后的物相变化。

关键词：废旧三元锂离子电池碳热还原优先提锂浸出率

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Comparison study on measurement of rail weld joint between inertial reference method and multi-point chord reference method

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Railway Sciences 2024年第1期3卷 69-83页

作者： Yifan Shi Yuan Wang xiaozhou liu Ping Wang Track Reasearch lab School of Civil EngineeringSouthwest Jiaotong University(SWJTU)ChengduChina Shenzhen EboRail Technology Co. Ltd.ShenzhenChina College of Urban Transportation and logistics Shenzhen Technology UniversityShenzhenChina The Hong Kong Polytechnic University Hung HomChina

Purpose – Straightness measurement of rail weld joint is of essential importance to railway maintenance. Dueto the lack of efficient measurement equipment, there has been limited in-depth research on rail weld joint with a5-m wavelength range, leaving a significant knowledge gap in this ***/methodology/approach – In this study, the authors used the well-established inertial referencemethod (IR-method), and the state-of-the-art multi-point chord reference method (MCR-method). Two methodshave been applied in different types of rail straightness measurement trollies, respectively. These instrumentswere tested in a high-speed rail section within a certain region of China. The test results were ultimatelyvalidated through using traditional straightedge and feeler gauge methods as reference data to evaluate the railweld joint straightness within the 5-m wavelength *** – The research reveals that IR-method and MCR-method produce reasonably similar measurementresults for wavelengths below 1 m. However, MCR-method outperforms IR-method in terms of accuracy forwavelengths exceeding 3 m. Furthermore, it was observed that IR-method, while operating at a slower speed,carries the risk of derailing and is incapable of detecting rail weld joints and low joints within the ***/value – The research compare two methods’ measurement effects in a longer wavelength rangeand demonstrate the superiority of MCR-method.

关键词： Rail weld joint Inertial reference method Short-wavelength irregularities Multi-point chord reference method 5-m wavelength range