检索结果-南通市图书馆

Dynamic response of sandwich panel attached with a double mass-spring-damping system to shallow-buried explosion:Analytical modeling

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2024年第2期67卷 568-586页

作者： ZHANG DuJiang zhao zhenyu GAO HuiYao LU TianJian State Key Laboratory of Mechanics and Control for Aerospace Structures Nanjing University of Aeronautics and AstronauticsNanjing 210016China MIIT Key Laboratory of Multifunctional Lightweight Materials and Structures(MLMS) Nanjing University of Aeronautics and AstronauticsNanjing 210016China

How to ensure the safety of occupants has become a challenge for protective design of armored vehicles against intensive blast *** this study,for armored vehicles subjected to shallow-buried explosions,an analytical model was established to characterize the dynamic performance of an all-metallic sandwich floorboard attached with a double mass-spring-damping system(mimicking seat and occupant),with the former consisting of a front face,a core and a rear *** validation,numerical simulations with the method of finite elements(FE)were *** agreement between analytical predictions and numerical results was *** analytical model was then employed to quantify the effects of explosive mass,yield stress of material make,configurational parameters of sandwich panel,spring stiffness,and damping coefficient on dynamic response of the sandwich panel and double mass-spring-damping *** increasing explosive mass and decreasing yield stress of material make,the peak displacements of rear face,seat and occupant were all found to *** core relative density was increased,these peak displacements also increased when the ratio of face thickness to core height was relatively *** the ratio of face thickness to core height led to increased peak accelerations of seat and *** peak displacement of rear face was insensitive to the increase of either spring stiffness or damping coefficient,while the peak acceleration of occupant increased with increasing spring *** increasing the damping coefficient between the rear face and seat or that between the seat and occupant or both,the peak acceleration of occupant *** occupant safety duly considered,the proposed analytical model provides useful guidance for designing high-performance protective structures for armored vehicles subjected to intensive blast loadings.

关键词： analytical model shallow-buried explosion sandwich panel occupant safety mass-spring-damping system

同方期刊数据库

Parameters identification of UCAV flight control system based on predator-prey particle swarm optimization

在线全文

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2013年第1期56卷 121-132页

作者： DUAN HaiBin YU YaXiang zhao zhenyu Science and Technology on Aircraft Control Laboratory School of Automation Science and Electrical EngineeringBeihang University

With the improvement of the aircraft flight performance and development of computing science,uninhabited combat aerial vehicle(UCAV) could accomplish more complex *** this also put forward stricter requirements for the flight control system,which are the crucial issues of the whole UCAV system *** paper proposes a novel UCAV flight controller parameters identification method,which is based on predator-prey particle swarm optimization(PSO) algorithm.A series of comparative experimental results verify the feasibility and effectiveness of our proposed approach in this paper,and a predator-prey PSO-based software platform for UCAV controller design is also developed.

关键词： uninhabited combat aerial vehicle(UCAV) particle swarm optimization(PSO) parameters identification predator-prey

Smart Contract Vulnerability Detection Method Based on Feature Graph and Multiple Attention Mechanisms

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Computers, Materials & Continua 2024年第5期79卷 3023-3045页

作者： Zhenxiang He zhenyu zhao Ke Chen Yanlin Liu School of Cyber Security Gansu University of Political Science and LawLanzhou730070China

The fast-paced development of blockchain technology is ***,the security concerns of smart contracts represent a significant challenge to the stability and dependability of the entire blockchain *** smart contract vulnerability detection primarily relies on static analysis tools,which are less efficient and *** deep learning methods have improved detection efficiency,they are unable to fully utilize the static relationships within ***,we have adopted the advantages of the above two methods,combining feature extraction mode of tools with deep learning ***,we have constructed corresponding feature extraction mode for different vulnerabilities,which are used to extract feature graphs from the source code of smart ***,the node features in feature graphs are fed into a graph convolutional neural network for training,and the edge features are processed using a method that combines attentionmechanismwith gated ***,the revised node features and edge features are concatenated through amulti-head *** result of the splicing is a global representation of the entire feature *** method was tested on three types of data:Timestamp vulnerabilities,reentrancy vulnerabilities,and access control vulnerabilities,where the F1 score of our method reaches 84.63%,92.55%,and 61.36%.The results indicate that our method surpasses most others in detecting smart contract vulnerabilities.

关键词： Blockchain smart contracts deep learning graph neural networks

Microstructures and Dielectric Properties of Ba_(1-x)Sr_xTiO_3 Ceramics Doped with B_2O_3-Li_2O Glasses for LTCC Technology Applications

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2012年第3期28卷 280-284页

作者： Xiujian Chou zhenyu zhao Miaoxuan Du Jun Liu Jiwei Zhai Key Laboratory of Instrumentation Science&Dynamic Measurement Ministry of EducationNational Key Labora-tory of Science and Technology on Electronic Test and Measurement(North University of China)Taiyuan 030051China Functional Materials Research Laboratory Tongji UniversityShanghai 200092China

Ba1-xSrxTiO3 ceramics, doped with B2O3-Li2O glasses have been fabricated via a traditional ceramic process at a low sintering temperature of 900 ℃ using liquid-phase sintering aids. The microstructures and di- electric properties of B2O3-Li2O glasses doped Ba1-xSrxTiO3 ceramics have been investigated systemat- ically. The temperature dependence dielectric constant and loss reveals that B2O3-Li2O glasses doped Ba1-xSrxTiO3 ceramics have di？usion phase transformation characteristics. For 5 wt% B2O3-Li2O glasses doped Ba0.55Sr0.45TiO3 composites, the tunability is 15.4% under a dc-applied electric field of 30 kV/cm at 10 kHz; the dielectric loss can be controlled about 0.0025; and the Q value is 286. These composite ceramics sintered at low temperature with suitable dielectric constant, low dielectric loss, relatively high tunability and high Q value are promising candidates for multilayer low-temperature co-fired ceramics （LTCC） and potential microwave tunable devices applications.

关键词： Sintering Ferroelectricity Dielectric properties Microstructure

In-situ deposition of apatite layer to protect Mg-based composite fabricated via laser additive manufacturing

在线全文

学校读者我要写书评

暂无评论

Journal of Magnesium and Alloys 2023年第2期11卷 629-640页

作者： Youwen Yang Changfu Lu Lida Shen zhenyu zhao Shuping Peng Cijun Shuai Institute of Bioadditive Manufacturing Jiangxi University of Science and TechnologyNanchang 330013China Jiangsu Key Laboratory of Precision and Micro-Manufacturing Technology Nanjing University of Aeronautics and AstronauticsNanjing 210016China Shenzhen Institute of Information Technology Shenzhen 518172China NHC Key Laboratory of Carcinogenesis School of basic Medical ScienceCentral South UniversityChangshaHunan 410013China School of energy and machinery engineering Jiangxi University of Science and TechnologyNanchang 330013China State Key Laboratory of High Performance Complex Manufacturing Central South UniversityChangsha 410083China

Biodegradable magnesium(Mg) and its alloy show huge potential as temporary bone substitute due to the favorable biocompatibility and mechanical compatibility. However, one issue deserves attention is the too fast degradation. In this work, mesoporous bioglass(MBG)with high pore volume(0.59 cc/g) and huge specific surface area(110.78 m^(2)/g) was synthesized using improved sol-gel method, and introduced into Mg-based composite via laser additive manufacturing. Immersion tests showed that the incorporated MBG served as powerful adsorption sites, which promoted the in-situ deposition of apatite by successively adsorbing Ca2+and HPO42-. Such dense apatite film acted as an efficient protection layer and enhanced the corrosion resistance of Mg matrix, which was proved by the electrochemical impedance spectroscopy measurements. Thereby, Mg based composite showed a significantly decreased degradation rate of 0.31 mm/year. Furthermore,MBG also improved the mechanical properties as well as cell behavior. This work highlighted the advantages of MBG in the fabrication of Mg-based implant with enhanced overall performance for orthopedic application.

关键词： Laser addictive manufacture Mg-based composite Mesoporous bioglass In-situ deposition Degradation behavior

Strength optimization of ultralight corrugated-channel-core sandwich panels

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2019年第8期62卷 1467-1477页

作者： zhao zhenyu LI Lang WANG Xin ZHANG QianCheng HAN Bin LU TianJian State Key Laboratory for Strength and Vibration of Mechanical Structures Xi'an Jiaotong University Xi'an 710049 China State Key Laboratory of Mechanics and Control of Mechanical Structures Nanjing University of Aeronautics and Astronautics Nanjing 210016 China Nanjing Center for Multifunctional Lightweight Materials and Structures (MLMS) Nanjing University of Aeronautics and Astronautics Nanjing 210016 China School of Mechanical Engineering Xi'an Jiaotong University Xi'an 710049 China

Novel ultralight sandwich panels, which are comprised of corrugated channel cores and are faced with two identical solid sheets,subjected to generalized bending are optimally designed for minimum mass. A combined analytical and numerical(finite element) investigation is carried out. Relevant failure mechanisms such as face yielding, face buckling, core yielding and core buckling are identified, the load for each failure mode derived, and the corresponding failure mechanism maps constructed. The analytically predicted failure loads and failure modes are validated against direct finite element simulations, with good agreement achieved. The optimized corrugated channel core is compared with competing topologies for sandwich construction including corrugations, honeycombs and lattice trusses, and the superiority of the proposed structure is demonstrated. Corrugated-channel-core sandwich panels hold great potential for multifunctional applications, i.e., simultaneous load bearing and active cooling.

关键词： sandwich panel corrugated channel generalized bending optimization

Functional biomaterials for tendon/ligament repair and regeneration

在线全文

学校读者我要写书评

暂无评论

Regenerative Biomaterials 2022年第1期9卷 1061-1079页

作者： Yunkai Tang Zhen Wang Lei Xiang zhenyu zhao Wenguo Cui Department of Orthopaedics Shanghai Key Laboratory for Prevention and Treatment of Bone and Joint DiseasesShanghai Institute of Traumatology and OrthopaedicsRuijin HospitalShanghai Jiao Tong University School of MedicineShanghai 200025P.R.China

With an increase in life expectancy and the popularity of highintensity exercise,the frequency of tendon and ligament injuries has also *** to the specificity of its tissue,the rapid restoration of injured tendons and ligaments is challenging for *** review summarizes the latest progress in cells,biomaterials,active molecules and construction technology in treating tendon/ligament *** characteristics of supports made of different materials and the development and application of different manufacturing methods are *** development of natural polymers,synthetic polymers and composite materials has boosted the use of *** addition,the development of electrospinning and hydrogel technology has diversified the production and treatment of ***,this article briefly introduces the structure,function and biological characteristics of tendons/***,it summarizes the advantages and disadvantages of different materials,such as natural polymer scaffolds,synthetic polymer scaffolds,composite scaffolds and extracellular matrix(ECM)-derived biological scaffolds,in the application of tendon/ligament *** then discuss the latest applications of electrospun fiber scaffolds and hydrogels in regeneration ***,we discuss the current problems and future directions in the development of biomaterials for restoring damaged tendons and ligaments.

关键词： tendon/ligament repair biomaterials electrospinning hydrogel tissue regeneration

Charge collection of single event effects at Bragg's peak

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2011年第2期54卷 268-272页

作者： LIU Zheng CHEN ShuMing LIANG Bin LIU BiWei zhao zhenyu College of Computer National University of Defense Technology Changsha 410073 China

Using Geant4 Monte Carlo code and Technology Computer-Aided Design(TCAD) simulation,energy deposition and charge collection of single event effects(SEE) are studied,which are induced by low-energy protons and α particles in small feature size *** analyzed charge collection of SEE especially at Bragg's peak and obtained two types of deposited energy distributions of protons and α particles at different incident *** two components of the total charge collected are quantified,which are due to drift current of the space charge region and current in the funnel region *** explain the high soft error rate in experiments of low energy proton.

关键词： Bragg's Peak charge collection low-energy proton linear energy transfer

Dual-level stress plateaus in honeycombs subjected to impact loading:perspectives from bucklewaves, buckling and cell-wall progressive folding

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 2019年第1期35卷 70-77,I0003页

作者： Lang Li zhenyu zhao Rui Zhang Bin Han Qiantheng Zhang Tian Jian Lu State Key Laboratory for Strength and Vibration of Mechanical Structures Xi'an Jiaotong UniversityXi'an 710049China State Key Laboratory of Mechanics and Control of Mechanical Structures Nanjing University of Aeronautics and AstronauticsNanjing 210016China MOE Key Laboratory for Multifunctional Materials and Structures Xi'an Jiaotong UniversityXi'an 710049China School of Mechanical Engineering Xi'an Jiaotong UniversityXi'an 710049China School of Engineering Brown UniversityProvidenceRI 02912USA Research Institute of Xi'an Jiaotong University ZhejiangHangzhou 311215China

Dual-level stress plateaus (i.e., relatively short peak stress plateaus, followed by prolonged crushing stress plateaus) in metallic hexagonal honeycombs subjected to out-of-plane impact loading are characterized using a combined numerical and analytical study, with the influence of the strain-rate sensitivity of the honeycomb pare nt material accounted for. The predicti ons are validated against existing experimental measurements, and good agreement is achieved. It is demonstrated that honeycombs exhibit dual-level stress plateaus when bucklewaves are initiated and propagate in cell walls, followed by buckling and progressive folding of the cell walls. The abrupt stress drop from peak to crushing plateau in the compressive stress versus strain curve can be explained in a way similar to the quasi-static buckling of a clamped plate. The duration of the peak stress plateau is more evident for strain-rate insensitive honeycombs.

关键词： Honeycomb Impact loading Dual-level stress Strain-rate sensitivity