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Classification of inelastic deformation and material-intrinsic indices about mechanical performance of general solid matter

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Science China(Physics,Mechanics & Astronomy) 2023年第11期66卷 155-178页

作者： yichao zhu Shaoshuai Li Biao Wang Department of Engineering Mechanics Dalian University of TechnologyDalian116024China State Key Laboratory of Structural Analysis Optimization and CAE Software for Industrial EquipmentDalian University of TechnologyDalian116024China School of Physics and Sino-French Institute of Nuclear Engineering and Technology Sun Yat-sen UniversityGuangzhou510275China Research Institute of Interdisciplinary Science Dongguan University of TechnologyDongguan523808China

The present article is aimed to detect material-intrinsic indices that can be used to supervise the mechanical performance of general solid matter.The novelty carried in this article can be summarised as follows.Firstly,an inelastic deformation state of almost any solid matter can be treated as the combination of two fundamental modes due to different microscopic causation:Mode I inelastic distortion due to the movement of sliding types of defects and Mode II inelastic dilation due to the evolution of voids/bubbles.Secondly,each inelastic deformation mode is characterised by a single principal inelastic deformation descriptor(PIDD):Mode I by a newly introduced quantity of maximum distortional angle changeαand Mode II by the logarithm of dilating magnificationω.In particular,the concept of maximum distortional angle change gives rise to a geometrically intuitive yield criterion ofα>α_(c),which in situations of small deformation,is shown to asymptote von Mise's,and to become Tresca's in cases of plane stress.Thirdly,the deformation process of a solid matter under monotonic and ambient loads is formulated by means of trajectories of thermodynamic equilibria with respect to the PIDD pair.Then a pair of physical quantities which measure the stresses needed to change the local PIDD state are singled out.Being termed as inelastic deformation resistances(IDRs),these two quantities are shown to depend only on the onsite atomic configurations.It is also shown that key descriptive properties about the mechanical behaviours of materials,such as ductility,are encoded in IDRs as functions of PIDDs.Hence the IDR pair may serve as material performance indices that may be more intrinsic than conventional stress-strain relationships.

关键词： inelastic deformation modes mechanical performance index thermodynamic principal inelastic deformation descriptor inelastic deformation resistance

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基于渐近分析法的复杂截面梁振动分析

力学学报 2024年第2期56卷 494-505页

作者：宋子文孙直朱一超大连理工大学工程力学系工业装备结构分析优化与CAE软件全国重点实验室辽宁大连116024 大连理工大学宁波研究院浙江宁波315016

梁结构在工程工业中发挥着重要的作用,梁的自振问题能够体现其本征动力学特性,是梁动力学分析中的基本问题.经典梁理论的提出往往基于不同的假设,文章采用渐近分析的方法,以梁的截面尺寸与长度之比为特征参数,严格地推导了三维梁结构的... 详细信息

梁结构在工程工业中发挥着重要的作用,梁的自振问题能够体现其本征动力学特性,是梁动力学分析中的基本问题.经典梁理论的提出往往基于不同的假设,文章采用渐近分析的方法,以梁的截面尺寸与长度之比为特征参数,严格地推导了三维梁结构的一维等效振动分析模型.基于梁结构几何特征的参数的引入,有助于确定梁结构应力场和位移场等物理量之间的真实量级关系.渐近分析结果表明,纯弯曲变形只是细长梁振动分析中的首阶项,对于复杂截面梁结构仍然可以使用与欧拉梁模型复杂度相似的一维等效梁模型进行振动分析.以精细三维有限元的计算结果为基准,验证了所提出的一维等效梁模型用于振动分析的准确性和有效性.一维等效梁模型可以在商业有限元软件中通过自定义截面等内嵌模块便捷地实现.对比有限元软件中多种梁单元的计算结果发现,在相似的模型复杂度下,等效模型对细长梁自振频率的分析精度与稳定性显著优于在商业有限元软件中直接选择复杂梁截面使用梁单元计算的结果.

关键词：渐近分析法复杂截面欧拉梁自由振动

Throughput Analysis of Dynamic Spectrum Anti-Jamming Multiple-Access in HF Communication Systems

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China Communications 2018年第9期15卷 85-94页

作者： yichao zhu Chao Guo Xiaoxue Wang China Ship Research and Development Academy Beijing 100101 China

A multiple-access networking scheme based on the new dynamic spectrum anti-jamming system is proposed in this paper. The network consists of a center node and multiple user nodes. The center node detects spectrum holes in the operation band periodically according to the user performance target. Detected spectrum holes are allocated to users who request communication. Throughput of this networking scheme is analyzed over a high-frequency(HF) interference channel. The effect of error correction coding and spectrum hole information transmission error is discussed. Throughput of this scheme and conventional frequency-hopping multiple-access(FHMA) scheme are compared. Results show that user performance increase leads to throughput decrease, which can be offset by error correction coding. If spectrum hole information transmission is in error, the throughput is not affected much as long as the bit error rate is below 10-2. Furthermore, throughput of this scheme is obviously superior to the throughput of FHMA scheme.

关键词：抗干扰系统产量分析动态光谱通讯系统多重存取 HF 信息传播

Ultrashort-time liquid phase sintering of high-performance fine-grain tungsten heavy alloys by laser additive manufacturing

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Journal of Materials Science & Technology 2021年第31期90卷 30-36页

作者： Shangcheng Zhou Yao-Jian Liang yichao zhu Benpeng Wang Lu Wang Yunfei Xue School of Materials Science and Engineering Beijing Institute of TechnologyBeijing 100081China

Liquid phase sintering(LPS)is a proven technique for preparing large-size tungsten heavy alloys(WHAs).However,for densification,this processing requires that the matrix of WHAs keeps melting for a long time,which simultaneously causes W grain coarsening that degenerates the performance.This work develops a novel ultrashort-time LPS method to form bulk high-performance fine-grain WHAs based on the principle of laser additive manufacturing(LAM).During LAM,the high-entropy alloy matrix(Al_(0.5)Cr_(0.9)FeNi_(2.5)V_(0.2))and W powders were fed simultaneously but only the matrix was melted by laser and most W particles remained solid,and the melted matrix rapidly solidified with laser moving away,producing an ultrashort-time LPS processing in the melt pool,i.e.,laser ultrashort-time liquid phase sintering(LULPS).The extreme short dwell time in liquid(-1/10,000 of conventional LPS)can effectively suppress W grain growth,obtaining a small size of 1/3 of the size in LPS WHAs.Meanwhile,strong convection in the melt pool of LULPS enables a nearly full densification in such a short sintering time.Compared with LPS WHAs,the LULPS fine-grain WHAs present a 42%higher yield strength,as well as an enhanced susceptibility to adiabatic shear banding(ASB)that is important for strong armor-piercing capability,indicating that LULPS can be a promising pathway for forming high-performance WHAs that surpass those prepared by conventional LPS.

关键词： Tungsten heavy alloy Laser additive manufacturing Liquid phase sintering

Activation of Rac1-PI3K/Akt is required for epidermal growth factorinduced PAK1 activation and cell migration in MDA-MB-231 breast cancer cells

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The Journal of Biomedical Research 2011年第4期25卷 237-245页

作者： Yu Yang Jun Du Zhenzhen Hu Jiaojing Liu Yinhui Tian yichao zhu Le Wang Luo Gu Department of Physiology Nanjing Medical University Nanjing Jiangsu 210029 China Cancer Center Nanjing Medical University Nanjing Jiangsu 210029 China

Epidermal growth factor （EGF） may increase cell motility, an event implicated in cancer cell invasion and metastasis. However, the underlying mechanisms for EGF-induced cell motility remain elusive. In this study, we found that EGF treatment could activate Ras-related C3 botulinum toxin substrate 1 （Racl）, PI3K/Akt and p21- actived kinase （PAK1） along with cell migration. Ectopic expression of PAK1 K299R, a dominant negative PAK1 mutant, could largely abolish EGF-induced cell migration. Blocking PI3K/Akt signalling with LY294002 or Akt siRNA remarkably inhibited both EGF-induced PAK1 activation and cell migration. Furthermore, expression of dominant-negative Racl （T17N） could largely block EGF-induced PI3K/Akt-PAK1 activation and cell migration. Interestingly, EGF could induce a significant production of ROS, and N-acetyl-L-cysteine, a scavenger of ROS which abolished the EGF-induced ROS generation, cell migration, as well as activation of PI3K/Akt and PAK, but not Racl. Our study demonstrated that EGF-induced cell migration involves a cascade of signalling events, including activation of Racl, generation of ROS and subsequent activation of PI3K/Akt and PAK1.

关键词： breast cancer cell epidermal growth factor migration Ras-related C3 botulinum toxin substrate 1（Rac1） PI3K/Akt p21-actived kinase （PAK1）

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直升机复合装甲典型攻角下的防弹能力分析

直升机技术 2024年第1期 7-10页

作者：李文智郑林峰陈忱曹瑶琴朱怡超中国直升机设计研究所江西景德镇333001

武装直升机作为战场的战略攻防利器,使用装甲是最典型的防护方式。目前,直升机装甲的防护能力均是以弹体垂直入射时可防护的距离和可防护的最大口径弹种表示,但研究发现,实际状态下弹体几乎不可能以垂直入射的方式实现打击,所以装甲的... 详细信息

武装直升机作为战场的战略攻防利器,使用装甲是最典型的防护方式。目前,直升机装甲的防护能力均是以弹体垂直入射时可防护的距离和可防护的最大口径弹种表示,但研究发现,实际状态下弹体几乎不可能以垂直入射的方式实现打击,所以装甲的实际防护能力并未被最大限度地发挥出来。文章通过设计包线试验的方法探究了直升机现用的陶瓷复合装甲在典型攻角下的防护规律,并进行了分析研究,提出了可能的装甲防护力提升设计思路,在倾斜15°的布置方式下,防弹性能可提升19.1%左右。

关键词：复合装甲典型角度攻角防弹能力

Signal and reference wave dually encrypted digital holographic system

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Chinese Science Bulletin 2008年第19期53卷 2935-2939页

作者： zhu yichao ZHANG JiaSen GONG QiHuang State Key Laboratory for Mesoscopic Physics and Department of Physics Peking University Beijing 100871 China

We propose a secure digital holographic system with signal and reference waves dually encrypted. Two random phase masks are used to encrypt the images in the input and the Fourier planes. The reference beam is phase encoded by another random phase mask. The encrypted image and the key are recorded by a CCD camera. The data can be processed or transferred directly by computer. We theoretically and experimentally demonstrate encryption and decryption of multiple images and the results show a high quality and good fault tolerance.

关键词：光学密码数字全息术信号

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中国劳动生产率增长动能转换与机制创新研究

数量经济技术经济研究 2016年第9期33卷 58-75页

作者：朱益超墨尔本大学

从三次产业、产业劳动生产率和劳动力配置结构、变迁动能等3个维度，采取指数分析、对数分析和分段回归分析相结合，对1980~2014年中国劳动生产率增长的源泉和动能进行实证分析。研究结果表明，在整体劳动生产率年均增长中，第三产业贡... 详细信息

从三次产业、产业劳动生产率和劳动力配置结构、变迁动能等3个维度，采取指数分析、对数分析和分段回归分析相结合，对1980~2014年中国劳动生产率增长的源泉和动能进行实证分析。研究结果表明，在整体劳动生产率年均增长中，第三产业贡献度48．4％，第二产业贡献度43．5％，第一产业贡献度8．1％；产业劳动生产率贡献度占79．6％，产业劳动力配置结构贡献度20．4％；劳均设备资本贡献度85．7％，劳动力质量贡献度28．3％，产业资本配置结构贡献度～6．7％，人口就业率贡献度-3．0％，消费与产出成长指数之比则基本零贡献。中国劳动生产率的动能转换与机制创新的主要方向和着力点，在于强势推进产能转型升级、居民增收扩消、劳动扩量提质、资本深化量质并举、工业经济强身健体、新型城镇化改革和要素配置优化调整。

关键词：整体劳动生产率产业劳动生产率劳均设备资本资本比值

内置等强缩尺3D打印支护系统的矿山相似物理模拟试验研究

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中国矿业大学学报 2022年第2期51卷 232-243,256页

作者：冯晓巍汪明坤薛飞赵同阳宋万新魏群朱毅超中国矿业大学矿业工程学院江苏徐州221116 绍兴文理学院土木工程学院浙江绍兴312000 山东科技大学能源与矿业工程学院山东青岛266590 中国矿业大学煤炭资源与安全开采国家重点实验室江苏徐州221116 江苏理工学院机械工程学院江苏常州213001

相似模拟试验方法是矿山工程研究中一种重要的研究手段,它在解析岩层移动、矿山压力、多场耦合等方面具有明显优势.为进一步优化这种试验方法,本文利用3D打印技术制作缩尺支护构件并将其植入相似物理模型,整套模拟系统按照30∶1的比例... 详细信息

相似模拟试验方法是矿山工程研究中一种重要的研究手段,它在解析岩层移动、矿山压力、多场耦合等方面具有明显优势.为进一步优化这种试验方法,本文利用3D打印技术制作缩尺支护构件并将其植入相似物理模型,整套模拟系统按照30∶1的比例以工程模型为原型进行缩尺,其中煤岩层和支护系统均遵照等强原则进行还原.缩尺煤岩层采用混凝土材料制备,缩尺支护系统采用不锈钢粉末3D打印制作成型;同时,本文设计加工了能够将相似物理模型适用于MTS伺服压力试验机的高强加载框架.测试中,通过声发射、数字散斑以及全程录像分析模型的微观破坏机理、位移场变化过程以及模型失效特征.测试结果表明:巷道周边关键测点位移变化、巷道和支护系统变形失效特征以及整体岩层变形破坏分区与真实情形高度吻合,符合矿山压力作用下的岩层变形规律.此外,声发射特征表明模型在多次受载过程中表现出凯瑟效应.本研究认为采用内置等强缩尺的3D打印支护系统具有极好的适应性,可提高测试精度,对于提升相似物理模拟研究水平具有参考价值和现实意义.

关键词：相似物理试验 3D打印支护系统失效特征数字散斑