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Computer Modeling in Engineering & Sciences 2023年第2期134卷 981-1003页

作者： Jintao Liu Juan Zhao xiaowei shen College of Architecture and Civil Engineering Xinyang Normal UniversityXinyang464000China College of Mechanics and Materials Hohai UniversityNanjing211100China

In this work,an acoustic topology optimizationmethod for structural surface design covered by porous materials is *** analysis of acoustic problems is performed using the isogeometric boundary *** the element density of porousmaterials as the design variable,the volume of porousmaterials as the constraint,and the minimum sound pressure or maximum scattered sound power as the design goal,the topology optimization is carried out by solid isotropic material with penalization(SIMP)*** get a limpid 0–1 distribution,a smoothing Heaviside-like function is *** obtain the gradient value of the objective function,a sensitivity analysis method based on the adjoint variable method(AVM)is *** find the optimal solution,the optimization problems are solved by the method of moving asymptotes(MMA)based on gradient *** examples verify the effectiveness of the proposed topology optimization method in the optimization process of two-dimensional acoustic ***,the optimal distribution of sound-absorbingmaterials is highly frequency-dependent and usually needs to be performed within a frequency band.

关键词： Boundary element method isogeometric analysis two-dimensional acoustic analysis sound-absorbing materials topology optimization adjoint variable method

A review on the rational design and fabrication of nanosized highentropy materials

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Nano Research 2023年第5期16卷 7874-7905页

作者： Yuanbo Zhou xiaowei shen Tao Qian Chenglin Yan Jianmei Lu Collaborative Innovation Center of Suzhou Nano Science and Technology College of Chemistry Chemical Engineering and Materials Science Soochow University199 Ren’ai RoadSuzhou 215123China Key Laboratory of Core Technology of High Specific Energy Battery and Key Materials for Petroleum and Chemical Industry College of EnergySoochow UniversitySuzhou 215006China School of Chemistry and Chemical Engineering Nantong UniversityNantong 226019China School of Electrical Engineering Nantong UniversityNantong 226019China Light Industry Institute of Electrochemical Power Sources Suzhou 215600China

High-entropy materials are mainly composed of high-entropy alloys(HEAs)and their *** them,HEAs account for a big *** a new kind of alloy,they are now arousing great interests because of their high mechanical strength,extraordinary fracture toughness,corrosion resistance compared with traditional *** characteristics allow the use of HEAs in various fields,including mechanical manufacturing,heat-resistant,radiation-resistant,corrosion-resistant,wear-resistant coatings,energy storage,heterocatalysis,*** order to promote the extensive application of HEAs,it is of significance to realize their rational design and *** this paper,a systematic review focusing on the rational design and fabrication of nanosized HEAs is *** design principles of how to match different elements in HEAs and the premise for the formation of single-phase solid solution HEAs are first *** methods for the prediction of formation conditions and properties of HEAs are also in ***,a detailed description and comparison of the synthesis methods of HEAs and their derivate,as well as their growing mechanism under various synthetic environments is *** commonly used characterization methods for the detection of HEAs,along with the typical cases of the application of HEAs in industrial materials,energy storage materials and catalytic materials are also ***,the challenges and perspectives in the design and synthesis of HEAs would be *** hope this review will give guidance for the future development of HEAs materials.

关键词： high-entropy alloys high-entropy alloy(HEA)derivate rational design synthesis strategies characterization application

Altering the rate-determining step over cobalt single clusters leading to highly efficient ammonia synthesis

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National Science Review 2021年第5期8卷 110-118页

作者： Sisi Liu Mengfan Wang Haoqing Ji xiaowei shen Chenglin Yan Tao Qian College of Energy Key Laboratory of Advanced Carbon Materials and Wearable Energy Technologies of Jiangsu ProvinceSoochow University

Activation of high-energy triple-bonds of N2is the most significant bottleneck of ammonia synthesis under ambient conditions. Here, by importing cobalt single clusters as strong electron-donating promoter into the catalyst, the rate-determining step of ammonia synthesis is altered to the subsequent proton addition so that the barrier of N2dissociation can be successfully overcome. As revealed by density functional theory calculations, the N2dissociation becomes exothermic over the cobalt single cluster upon the strong electron backdonation from metal to the N2antibonding orbitals. The energy barrier of the positively shifted rate-determining step is also greatly reduced. At the same time, advanced sampling molecular dynamics simulations indicate a barrier-less process of the N2approaching the active sites that greatly facilitates the mass transfer. With suitable thermodynamic and dynamic property, a high ammonia yield rate of 76.2 μg h–1mgcat–*** superior Faradaic efficiency of 52.9% were simultaneously achieved.

关键词： nitrogen reduction reaction rate-determining step cobalt single cluster mass transfer molecular dynamics simulations

Single lithium-ion channel polymer binder for stabilizing sulfur cathodes

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National Science Review 2020年第2期7卷 315-323页

作者： Chaoqun Niu Jie Liu Tao Qian xiaowei shen Jinqiu Zhou Chenglin Yan College of Energy Collaborative Innovation Center of Suzhou Nano Science and Technology Key Laboratory of Advanced Carbon Materials and Wearable Energy Technologies of Jiangsu ProvinceSoochow University

Lithium–sulfur batteries have great potential for high-performance energy-storage devices, yet the severe diffusion of soluble polysulfide to electrolyte greatly limits their practical applications. To address the above issues, herein we design and synthesize a novel polymer binder with single lithium-ion channels allowing fast lithium-ion transport while blocking the shuttle of unnecessary polysulfide anions. In situ UV–vis spectroscopy measurements reveal that the prepared polymer binder has effective immobilization to polysulfide intermediates. As expected, the resultant sulfur cathode achieves an excellent specific capacity of 1310 mAh g-1at 0.2 C, high Coulombic efficiency of 99.5% at 0.5 C after 100 cycles and stable cycling performance for 300 cycles at 1 C(1 C = 1675 mA g-1). This study reports a new avenue to assemble a polymer binder with a single lithium-ion channel for solving the serious problem of energy attenuation of lithium–sulfur batteries.

关键词： polymer binders single lithium-ion channels polysulfide intermediates lithium–sulfur batteries

Insight into the reaction mechanism of sulfur chains adjustable polymer cathode for high-loading lithium-organosulfur batteries

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Journal of Energy Chemistry 2021年第5期30卷 238-244页

作者： Jinqiu Zhou Xi Zhou Yawen Sun xiaowei shen Tao Qian Chenglin Yan Soochow Institute for Energy and Materials Innovations College of EnergyKey Laboratory of Advanced Carbon Materials and Wearable Energy Technologies of Jiangsu ProvinceSoochow UniversitySuzhou 215006JiangsuChina Institute of Chemical Industry of Forestry Products Chinese Academy of ForestryNanjing 210042JiangsuChina

Small molecules with adjustable sulfur atoms in the confined structure were acted as precursor for the synthesis of polymer cathodes for lithium-organosulfur *** them,poly(diallyl tetrasulfide)(PDATtS)delivered a high capacity of 700 mAh g^(-1),stable capacity retention of 85%after 300 cycles,high areal capacity~4 m Ah cm^(-2) for electrode with up to 10.3 mg cm^(-2) *** insight into the reaction mechanism of PDATtS electrode that radicals arisen from the homolytic cleavage of S-S bond in PDATtS reacted with Li+to generate thiolates(RSLi)and insoluble lithium sulfides(Li_(2)S)or lithium disulfide(Li_(2)S_(2))was clearly verified by in-situ UV/Vis spectroscopy,nuclear magnetic resonance(NMR)studies and density-functional theory(DFT)***,based on the unique reaction mechanism,problems of rapid capacity fading due to the formation of soluble polysulfide intermediates and their serious shuttle effect in conventional lithium-sulfur(Li-S)batteries was totally avoided,realizing the dendrite-free lithium sulfur *** study sets new trends for avenues of further research to advance Li-S battery technologies.

关键词： Lithium-sulfur battery Organosulfur polymer Adjustable sulfur chains Cathode material

Low-temperature Li-S batteries enabled by all amorphous con version process of organosulfur cathode

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Journal of Energy Chemistry 2022年第1期31卷 496-502,I0013页

作者： Zhenkang Wang xiaowei shen Sijie Li Yuxuan Wu Tingzhou Yang Jie Liu Tao Qian Chenglin Yan College of Energy Key Laboratory of Advanced Carb on Materials and Wearable Energy Technologies of Jiangsu ProvinceSoochow UniversitySuzhou 215006JiangsuChina College of Chemistry and Chemical Engineering.Nantong University Seyuan 9Nantong 226000JiangsuChina

The high degree of crystallinity of discharging in termediates of Li-S batteries(Li_(2)S_(2)/Li_(2)S)causes a severe capacity attenuation at low ***,a sulfur-rich polymer is fabricated,which enables all the discharging in termediates to exist in an amorphous state without long-range order,promoti ng the substantial conversion of discharging intermediates and enhancing Li-S batteries'performance at low temperatures *** cathode material exhibits excellent performance both at room and low *** under an extremely low temperature(-40℃),the discharge capacity can remain 67% of that at room ***,in-situ UV/Vis spectroscopy and density functional theory calculations reveal that this organosulfur cathode undergoes a new mechanism during ***_(2)S_(6) and Li_(2)S_(3) are the primary discharging intermediates that are quite different from conventional Li-S *** results provide a new directi on for a broader range of applications of Li-S batteries.

关键词： Low temperature Organosulfur polymers Li-S battery Crystallinity

基于粒子群算法的稀疏阵列超声相控阵全聚焦成像

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应用声学 2020年第3期39卷 354-359页

作者：沈晓炜长沙理工大学汽车与机械工程学院长沙410114

为降低相控阵超声检测全聚焦算法的成像数据量及阵列稀疏优化的计算时间,研究了一种用于稀疏阵列全聚焦成像的阵列优化算法,并通过实验对其成像效果进行了验证。针对目前超声相控阵检测的全矩阵采集数据量大、全聚焦算法成像时间长的难... 详细信息

为降低相控阵超声检测全聚焦算法的成像数据量及阵列稀疏优化的计算时间,研究了一种用于稀疏阵列全聚焦成像的阵列优化算法,并通过实验对其成像效果进行了验证。针对目前超声相控阵检测的全矩阵采集数据量大、全聚焦算法成像时间长的难点,该文通过构建稀疏阵列,在保证成像质量的同时显著降低成像数据量,提高了全聚焦算法的成像效率。通过以主瓣宽度、旁瓣峰值以及主瓣峰值作为约束条件构建适应度函数,采用粒子群算法得到稀疏阵元位置分布并进行阵元权重修正,并将其用于稀疏全聚焦成像。相比全阵元成像,使用粒子群算法所得的稀疏阵列的阵元个数降低了56.25%、65.62%,数据使用量降低了80.86%、88.18%。在阵列优化方面,相比遗传算法减少了84.86%的计算时间。

关键词：稀疏阵列粒子群算法相控阵超声检测全聚焦算法

Gas exchange optimization in aircraft engines using sustainable aviation fuel:A design of experiment and genetic algorithm approach

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Energy and AI

Energy and AI 2024年第3期17卷 261-280页

作者： Zheng Xu Jinze Pei Shuiting Ding Longfei Chen Shuai Zhao xiaowei shen Kun Zhu Longtao Shao Zhiming Zhong Huansong Yan Farong Du Xueyu Li Pengfei Yang shenghui Zhong Yu Zhou Hangzhou International Innovation Institute Beihang UniversityHangzhou311115China Research Institute of Aero-Engine Beihang UniversityBeijing102206China Civil Aviation University of China Tianjin300300China Aircraft/Engine Integrated System Safety Beijing Key Laboratory Beijing100083China Aero Engine Academy of China Beijing101304China School of Energy and Power Engineering Beihang UniversityBeijing100083China AVIC Chengdu Aircraft Design and Research Institute Chengdu610091China AVIC Nanjing Engineering Institute of Aircraft Systems Nanjing211106China School of Transportation Science and Engineering Beihang UniversityBeijing100083China Faculty of Science and Engineering University of Nottingham Ningbo ChinaNingbo315100China

The poppet valves two-stroke(PV2S)aircraft engine fueled with sustainable aviation fuel is a promising option for general aviation and unmanned aerial vehicle propulsion due to its high power-to-weight ratio,uniform torque output,and flexible valve ***,its high-altitude gas exchange performance remains unexplored,presenting new opportunities for optimization through artificial intelligence(AI)*** study uses validated 1D+3D models to evaluate the high-altitude gas exchange performance of PV2S aircraft *** valve timings of the PV2S engine exhibit considerable flexibility,thus the Latin hypercube design of experiments(DoE)methodology is employed to fit a response surface model.A genetic algorithm(GA)is applied to iteratively optimize valve timings for varying *** optimization process reveals that increasing the intake duration while decreasing the exhaust duration and valve overlap angles can significantly enhance high-altitude gas exchange *** optimal valve overlap angle emerged as 93°CA at sea level and 82°CA at 4000 m *** effects of operating parameters,including engine speed,load,and exhaust back pressure,on the gas exchange process at varying altitudes are further *** higher engine speed increases trapping efficiency but decreases the delivery ratio and charging efficiency at various *** effect is especially pronounced at elevated *** increase in exhaust back pressure will significantly reduce the delivery ratio and increase the trapping *** study demonstrates that integrating DoE with AI algorithms can enhance the high-altitude performance of aircraft engines,serving as a valuable reference for further optimization efforts.

关键词： Poppet valves two-stroke Design of experiment Genetic algorithm optimization Heavy fuel aircraft engine High altitude gas exchange performance

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砂型及金属型铸造ZA27合金的压蠕变行为

特种铸造及有色合金 2003年第1期23卷 19-21页

作者：魏晓伟沈保罗四川大学

采用自制的试验装置研究了ZA2 7合金在砂型和金属型铸造条件下的压蠕变行为。结果表明 ,合金第一阶段的压蠕变量和稳态蠕变速率随着温度和应力的增高而增大 ,在较低温度时 ,金属型铸造合金第一阶段的蠕变量低于砂型铸造合金的。合金的... 详细信息

采用自制的试验装置研究了ZA2 7合金在砂型和金属型铸造条件下的压蠕变行为。结果表明 ,合金第一阶段的压蠕变量和稳态蠕变速率随着温度和应力的增高而增大 ,在较低温度时 ,金属型铸造合金第一阶段的蠕变量低于砂型铸造合金的。合金的压蠕变符合经验公式ln(t/s) =C -nln(σ/MPa) +Q/(RT) ,砂型铸造合金的应力指数n和蠕变激活能Q分别为 3.88和 85 .44kJ/mol,而金属型铸造合金的应力指数和蠕变激活能分别为 3.49和 81.0 2kJ/mol。合金的压蠕变由锌的点阵自扩散和位错的攀移控制 ,在整个试验温度和应力范围内 ,砂型铸造合金的压蠕变抗力高于金属型铸造合金的。

关键词： ZA27合金砂型铸造金属型铸造压蠕变

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完善黄金市场结构提高黄金市场效率

黄金 2007年第4期28卷 5-9页

作者：沈小炜华东师范大学商学院

中国黄金市场建立时间较短,市场效率较低,这在很大程度上是由于目前国内黄金市场结构不完善现状造成的。文中首先从黄金的特殊性、中国黄金市场的目标定位以及中国黄金市场对金融体系的影响入手,分析了完善国内黄金市场结构的重要性;其... 详细信息

中国黄金市场建立时间较短,市场效率较低,这在很大程度上是由于目前国内黄金市场结构不完善现状造成的。文中首先从黄金的特殊性、中国黄金市场的目标定位以及中国黄金市场对金融体系的影响入手,分析了完善国内黄金市场结构的重要性;其次结合目前国内黄金市场结构建设的实际情况,对限制市场效率发挥的主要原因进行了总结;最后对如何改进国内黄金市场结构,提出了具体措施。

关键词：黄金市场结构市场效率交易体系交易主体