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Structural modeling of sandwich structures with lightweight cellular cores

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Acta Mechanica Sinica 2007年第5期23卷 545-559页

作者： T.Liu z.C.Deng T.J.lu Department of Engineering Mechanics Northwestern Polytechnical UniversityXi'an 710072China MOE Key Laboratory of Strength and Vibration School of AerospaceXi'an Jiaotong UniversityXi'an 710049China

An effective single layered finite element （FE） computational model is proposed to predict the structural behavior of lightweight sandwich panels having two dimensional （2D） prismatic or three dimensional （3D） truss cores. Three different types of cellular core topology are considered： pyramidal truss core （3D）, Kagome truss core （3D） and corrugated core （2D）, representing three kinds of material anisotropy： orthotropic, monoclinic and general anisotropic. A homogenization technique is developed to obtain the homogenized macroscopic stiffness properties of the cellular core. In comparison with the results obtained by using detailed FE model, the single layered computational model can give acceptable predictions for both the static and dynamic behaviors of orthotropic truss core sandwich panels. However, for non-orthotropic 3D truss cores, the predictions are not so well. For both static and dynamic behaviors of a 2D corrugated core sandwich panel, the predictions derived by the single layered computational model is generally acceptable when the size of the unit cell varies within a certain range, with the predictions for moderately strong or strong corrugated cores more accurate than those for weak cores.

关键词： Cellular material Sandwich panel Homogenization Finite element

3D打印技术在舰船管系三维建模设计中的应用

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舰船科学技术 2024年第6期46卷 165-168页

作者：王晓橹沈阳理工大学辽宁沈阳110158

为提升复杂结构舰船管系的设计灵活性,研究3D打印技术在舰船管系三维建模设计中的应用。利用CAD软件建立舰船管系的二维模型,依据舰船管系三角面片的交线段,确定舰船管系的点、线、面关系,将其转换为舰船管系三维模型。将舰船管系三维模... 详细信息

为提升复杂结构舰船管系的设计灵活性,研究3D打印技术在舰船管系三维建模设计中的应用。利用CAD软件建立舰船管系的二维模型,依据舰船管系三角面片的交线段,确定舰船管系的点、线、面关系,将其转换为舰船管系三维模型。将舰船管系三维模型,导入切片软件中,利用切片引擎运行3D打印切片引擎增强处理算法,切片处理舰船管系三维模型,输出舰船管系三维模型的Gcode代码文件。将Gcode代码导入3D打印机,采用z字填充法填充舰船管系3D打印材料,实现舰船管系模型的3D打印。实验结果表明,该方法可以精准打印舰船管系三维模型,打印结果的尺寸偏差小,提升了舰船管系设计的灵活性。

关键词： 3D打印技术舰船管系三维建模设计三角面片切片引擎 z字填充法

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短包隐蔽通信下抗检测-干扰式攻击策略

陆军工程大学学报 2024年第1期3卷 36-42页

作者：张凌瑄鲁兴波隋元松卢辉 32369部队北京100043 军事科学院北京100091 陆军工程大学野战工程学院江苏南京210007

为应对潜在的检测-干扰式恶意攻击,提出了一种基于短包隐蔽通信的抗检测-干扰攻击策略,通过隐藏无线传输行为的存在来实现抗干扰。考虑到干扰机采用Shewhart变点检测实时判断源节点的传输行为,当判决源节点正在传输数据包后启动人工干... 详细信息

为应对潜在的检测-干扰式恶意攻击,提出了一种基于短包隐蔽通信的抗检测-干扰攻击策略,通过隐藏无线传输行为的存在来实现抗干扰。考虑到干扰机采用Shewhart变点检测实时判断源节点的传输行为,当判决源节点正在传输数据包后启动人工干扰。为隐藏无线传输行为,源节点随机选择一个起始时刻以低功率、低速率传输有限长编码数据包。数据包发送功率越小、编码长度越短,隐蔽性越强,抗检测-干扰式攻击性能越好,但发送功率小和编码长度短使得接收端数据包译码错误概率较大。以有效传输速率最大为目标对数据包发送功率和编码长度进行优化设计。结果表明,存在最优的发送功率和编码长度使系统在传输隐蔽性和可靠性之间取得最优折衷。数值仿真结果验证了理论分析,证明了所提方案的有效性以及优化数据包编码长度和发送功率的必要性。

关键词：短包通信隐蔽通信检测-干扰攻击 Shewhart变点检测最优包长

Recent progress and strategies of cathodes toward polysulfides shuttle restriction for lithium-sulfur batteries

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Rare Metals 2024年第9期43卷 4132-4161页

作者： Xing-You Rao Shuang-Fei Xiang Jian zhou zhen zhang Xiang-Yu Xu Yuan-Yuan Xu Xin-Chi zhou zheng-Dao Pan Su-Chong Tan Shi-Xing Dong zhou-lu Wang Yu-Tong Wu Yun-Lei zhou Xiang Liu Yi zhang Shan Jiang School of Energy Sciences and Engineering Nanjing Tech University School of Materials Science and Engineering and Institute of Smart Fiber Materials Zhejiang Sci-Tech University JiangSu Sailboat Petrochemical Co. Ltd Hangzhou Institute of Technology Xidian University

Lithium-sulfur batteries(LSBs) have already developed into one of the most promising new-generation high-energy density electrochemical energy storage systems with outstanding features including high-energy density, low cost, and environmental friendliness. However, the development and commercialization path of LSBs still presents significant limitations and challenges, particularly the notorious shuttle effect triggered by soluble longchain lithium polysulfides(LiPSs), which inevitably leads to low utilization of cathode active sulfur and high battery capacity degradation, short cycle life, etc. Substantial research efforts have been conducted to develop various sulfur host materials capable of effectively restricting the shuttle effect. This review firstly introduces the fundamental electrochemical aspects of LSBs, followed by a comprehensive analysis of the mechanism underlying the shuttle effect in Li–S batteries and its profound influence on various battery components as well as the overall battery performance. Subsequently, recent advances and strategies are systematically reviewed, including physical confinement, chemisorption, and catalytic conversion of sulfur hosts for restricting LiPSs shuttle effects. The interplay mechanisms of sulfur hosts and LiPSs are discussed in detail and the structural advantages of different host materials are highlighted. Furthermore, key insights for the rational design of advanced host materials for LSBs are provided, and the upcoming challenges and the prospects for sulfur host materials in lithium-sulfur batteries are also explored.

关键词： Host Lithium-sulfur batteries Polysulfides Shuttle effect

Diffusion behavior of Cr in gradient nanolaminated surface layer on an interstitial-free steel

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Journal of Materials Science & Technology 2019年第3期35卷 460-464页

作者： S.L.Xie z.B.Wang K.lu Shenyang National Laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences School of Materials Science and Engineering University of Science and Technology of China

Nanolaminated structures composed of low-angle grain boundaries(LAGBs) possess high thermal stability. In this paper, a gradient nanolaminated(GNL) surface layer with smooth finish was fabricated on an interstitial-free steel by means of surface mechanical rolling treatment. Microstructural observations demonstrated that the average lamellar thickness is about 80 nm in the topmost surface layer and increases with increasing depth. High thermal stability was confirmed in the GNL surface layer after annealing at 500℃. Diffusion measurements showed that effective diffusivity of Cr in GNL layer is 4–6 orders of magnitude higher than lattice diffusivity within the temperature range from 400 to 500℃. This might be attributed to numerous LAGBs or dislocation structures with a higher energy state in the GNL surface layer. This work demonstrates the possibility to advanced chromizing(or other surface alloying)processes of steels with formation of GNL surface layer, so that a thicker alloyed surface layer with a stable nanostructure is achieved.

关键词： Gradient nanolaminated structure Interstitial-free steel Diffusion Low-angle grain boundary Surface mechanical rolling treatment

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伊伐布雷定在儿童心血管疾病中的应用进展

中国当代儿科杂志 2024年第7期26卷 782-788页

作者：蒋露(综述) 孙慧超(审校) 重庆医科大学附属儿童医院心血管科/国家临床重点专科/儿童发育疾病研究教育部重点实验室/国家儿童健康与疾病临床医学研究中心/儿童发育重大疾病国家国际科技合作基地重庆400014

伊伐布雷定作为特异性I_(f)电流抑制剂,因其在降低心率的同时不影响心肌收缩力和血压,已广泛应用于成人慢性心力衰竭的治疗,并且在多种快速性心律失常中亦展现出良好的治疗效果。但伊伐布雷定在儿童心血管疾病的应用还有很多限制,该文... 详细信息

伊伐布雷定作为特异性I_(f)电流抑制剂,因其在降低心率的同时不影响心肌收缩力和血压,已广泛应用于成人慢性心力衰竭的治疗,并且在多种快速性心律失常中亦展现出良好的治疗效果。但伊伐布雷定在儿童心血管疾病的应用还有很多限制,该文就目前国内外关于伊伐布雷定治疗儿童心血管疾病的研究进展进行综述,以期为儿童心血管医生提供指导。

关键词：心力衰竭伊伐布雷定心律失常心脏移植儿童

Structural Damage Detection Using a Modified Artificial Bee Colony Algorithm

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Computer Modeling in Engineering & Sciences 2016年第4期111卷 335-355页

作者： H.J.Xu z.H.Ding z.R.lu J.K.Liu Department of Mechanics Sun Yat-sen UniversityGuangzhou 510006China

An optimization approach based on Artificial Bee Colony(ABC)algorithm is proposed for structural local damage detection in this *** objective function for the damage identification problem is established by structural parameters and modal assurance criteria(MAC).The ABC algorithm is presented to solve the certain objective *** the Tournament Selection Strategy and chaotic search mechanism is adopted to enhance global search ability of the certain algorithm.A coupled double-beam system is studied as numerical example to illustrate the correctness and efficiency of the propose *** simulation results show that the modified ABC algorithm can identify the local damage of the structural system efficiently even under measurement noise,which demonstrates the proposed algorithm has a higher damage diagnosis precision.

关键词： structural damage detection Artificial Bee Colony algorithm Modal Assurance Criteria coupled double-beam system Tournament Selection Strategy

信访：民众诉求表达与社会矛盾化解的重要制度安排

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浙江工商大学学报 2024年第05期 15-23页

作者：陈新卢志朋浙江工商大学公共管理学院

信访工作是中国共产党群众路线的重要体现，是党治国理政的一项特有制度安排，深嵌于中国国家治理场景中。信访制度发轫于新中国成立初期，历经改革开放后的恢复发展，到新时代党和国家对其的改革重塑，反映出不同历史阶段的时代特征。... 详细信息

信访工作是中国共产党群众路线的重要体现，是党治国理政的一项特有制度安排，深嵌于中国国家治理场景中。信访制度发轫于新中国成立初期，历经改革开放后的恢复发展，到新时代党和国家对其的改革重塑，反映出不同历史阶段的时代特征。在实践过程中，信访制度塑造了中央政府、基层政府与信访民众等多行为主体之间复杂的关系样态，呈现出“政府回应与社会抗争”“群众路线与维稳利器”“维权之举与谋利之术”等行为逻辑。就未来改革和研究议程而言，需从宏观上将信访融入国家治理整体格局中思考，从中观上优化信访制度本身的运行逻辑，从微观上健全和完善信访工作的各项机制。

关键词：人民信访群众路线社会矛盾法治化

Review on Hydrogen Embrittlement of Press-hardened Steels for Automotive Applications

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Acta Metallurgica Sinica(English Letters) 2023年第7期36卷 1123-1143页

作者： z.Wang Q.lu z.H.Cao H.Chen M.X.Huang J.F.Wang General Motors China Science Lab Shanghai201206China Department of Mechanical Engineering The University of Hong KongPokfulam RoadHong Kong999077China Key Laboratory for Advanced Materials of Ministry of Education School of Materials Science and EngineeringTsinghua UniversityBeijing100084China

Press-hardened steel(PHS)with an ultimate tensile strength(UTS)of 1500 MPa has been widely used in automotive body-in-white in the last two decades,due to its ultra-high strength and excellent formability that is achieved by hot stamping ***,the application of PHS with UTS exceeding 1500 MPa in automotive industry could be deferred due to the increased risk of hydrogen *** reduce this kind of risk,recent research efforts have been focused on various ways to optimize the microstructure of *** present review intends to summarize these efforts,to highlight present solutions to address hydrogen embrittlement,and to shed light on directions for future *** influence of microstructure on the hydrogen embrittlement of PHS has been discussed in terms of both the steel substrate and the surface *** substrate part covers the influence of martensite,carbides,inclusions,and retained austenite,while the surface part covers decarburization and oxidation,pre-coating,and trimming.

关键词： Hot stamping Press-hardened steels Coating-free Hydrogen embrittlement Fracture Al-Si coating