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Mechanical Characterization of Electroplated Ni Films by Micro-tensile Testing

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Chinese Journal of Mechanical Engineering 2009年第4期22卷 557-561页

作者： zhang Duanqin chu Jinkui Key Laboratory for Micro/Nano Technology and System of Liaoning Province Dalian University of Technology Dalian 116024 China

Mechanical properties of structural materials are particularly important for design, performance realization and reliability analysis of microelectromechanical systems （MEMS）. Furthermore, accurate database of mechanical properties at the micro scale can provide indispensable reference for establishing MEMS standard. Electroplated nickel film is one of the most favored structural materials used in MEMS, thus its mechanical properties has been studied for many years. However, the measured values show large scatter in Yotmg＇s modulus of nickel film. Young＇s modulus and yield stress of electroplated nickel film are measured by using a micro-tensile testing instrument. The tensile load applied on the specimen is measured by a load cell with accuracy 0.25 mN directly, without additional friction. Through measuring the axial stiffness coefficient of the tensile instnunent in situ, the tensile strain of the specimen is obtained by using two-serial spring model. The electroplated nickel films were fabricated from sulfarnate baths, and the gauge section is 500μm long and 10μm wide nominally, and thickness range between 25 μm and 50μm. The obtained Young＇s modulus from tensile testing is 83＋6 GPa for nickel specimens electroplated at current density of 20 mA/cm2 and it increases to 124＋5 GPa as current density is decreased to 10 mA/cm2. The phenomena are interpreted in terms of porosity of microstructure. The higher current density produced rnicrostucture with low density and high volume fraction of pores, and the microstructure of high porosity corresponds to a lower modulus. The measured values of Young＇s modulus are consistent with those of calculated from the exponential empirical formula between Young＇s modulus and porosity. The micro-tensile testing instrument can also be used for mechanical measurement of other MEMS films.

关键词： electroplated nickel micro-tensile testing Young's modulus porosity

Influence of static pre-loading on the dynamic bending strength of concrete with particle element modeling

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Science China(Technological Sciences) 2015年第2期58卷 284-296页

作者： WU Ming Xin zhang chu Han State Key Laboratory of Hydroscience and Engineering Tsinghua University

Experimental tests show that static pre-loading has a significant effect on the dynamic strength of *** on meso-scale particle element model,numerical simulations of dynamic bending tests with pre-loading are *** stress–strain relationships are then *** increase in dynamic strength is found when the pre-loadings are imposed within the elastic limit of ***,when the imposition of pre-loadings reaches the plastic or softening range,dynamic strengths may gradually decrease along with the increase in *** distribution of energy components and the failure modes are discussed to explain the mechanisms of the phenomena.

关键词： concrete static pre-loading dynamic bending strength rate effect particle element modeling

Strength failure of spatial reticulated structures under multi-support excitation

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Earthquake Engineering and Engineering Vibration 2011年第1期10卷 21-36页

作者： Ye Jihong zhang Zhiqiang chu Ye Key Laboratory of C ＆ PC Structure of Ministry of Education Southeast University Nanjing 210096 China

Under strong earthquakes, long-span spatial latticed structures may collapse due to dynamic instability or strength failure. The elasto-plastic dynamic behaviors of three spatial latticed structures, including two double-layer cylindrical shells and one spherical shell constructed for the 2008 Olympic Games in Beijing, were quantitatively examined under multi-support excitation （MSE） and uniform support excitation （USE）. In the numerical analyses, several important parameters were investigated such as the peak acceleration and displacement responses at key joints, the number and distribution of plastic members, and the deformation of the shell at the moment of collapse. Analysis results reveal the features and the failure mechanism of the spatial latticed structures under MSE and USE. In both scenarios, the double-layer reticulated shell collapses in the ＂overflow＂ mode, and the collapse is governed by the number of invalid plastic members rather than the total number of plastic members, beginning with damage to some of the local regions near the supports. By comparing the numbers and distributions of the plastic members under MSE to those under USE, it was observed that the plastic members spread more sufficiently and the internal forces are more uniform under MSE, especially in cases of lower apparent velocities in soils. Due to the effects of pseudo-static displacement, the stresses in the members near the supports under MSE are higher than those under USE.

关键词： multiple support excitation (MSE) uniform support excitation (USE) elastoplastic spatial latticed structure strength failure

An Information-Theoretic Approach to Effective Inference for Z-functionals

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Acta Mathematica Sinica,English Series 2009年第11期25卷 1893-1906页

作者： Chang chun WU Run chu zhang College of Mathematics and Information Engineering Jiaxing University Jiaxing 314001 P. R. China KLAS and School of Mathematics and Statistics Northeast Normal University Changchun 130024 P. R. China LMPC and School of Mathematical Sciences Nankai University Tianjin 300071 P. R. China

In this paper, through an information-theoretic approach, we construct estimations and confidence intervals of Z-functionals involving finite population and with the presence of auxiliary information. In particular, we give a method of estimating the variance of finite population with known mean. The modified estimates and confidence intervals for Z-functionals can adequately use the auxiliary information, at least not worse than what the standard ones do. A simulation study is presented to assess the performance of the modified estimates for the finite sample case.

关键词： confidence interval finite population modified Z-estimates information-theoretic approach Z-functional

Compromise 4~m2~n Plans with Clear Two-factor Interactions

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Acta Mathematicae Applicatae Sinica 2010年第1期26卷 99-106页

作者： Sheng-li Zhao Run-chu zhang School of Mathematical Sciences Qufu Normal University Qufu 273165 China LPMC and Department of Statistics School of Mathematical Sciences Nankai University Tianjin 300071 China

This paper gets some necessary conditions for the existence of some kinds of clear 4^m2^n compromise plans which allow estimation of all main effects and some specified two-factor interactions without assuming the remaining two-factor interactions being negligible. Some methods for constructing clear 4^m2^n compromise plans are introduced.

关键词： Compromise plan clear resolution

Discrete wavelet structure and discrete energy of classical plane light waves

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Chinese Physics B 2021年第4期30卷 139-143页

作者： Xing-chu zhang Wei-Long She Department of Physics and Information Engineering Guangdong University of EducationGuangzhou 510303China School of Physics Sun Yat-Sen UniversityGuangzhou 510275China Sino-French Institute of Nuclear Engineering and Technology Sun Yat-Sen UniversityZhuhai 519082China

We find by the wavelet transform that the classical plane light wave of linear polarization can be decomposed into a series of discrete Morlet *** the theoretical frame,the energy of the classical light wave becomes discrete;interestingly,the discretization is consistent with the energy division of P portions in Planck radiation theory,where P is an *** is shown that the changeable energy of a basic plane light wave packet or wave train is H_(0k)=nP0 kω(n=1,2,3,...;k=|k|),with discrete wavelet structure parameter n,wave vector k and idler frequency ω,and a constant p0 *** wave-particle duality from the Mach-Zehnder interference of single photons is simulated by using random basic plane light wave packets.

关键词： classic plane light wave discrete wavelet structure discrete energy

Cracking behaviors and strength of rock-like samples with steps of different geometries under shear stress

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Journal of Mountain Science 2021年第5期18卷 1352-1370页

作者： LE Hui-lin WEI Ji-hong SUN Shao-rui zhang chu-chu Department of Geology Engineering Hohai UniversityNanjing 210098China China Energy Engineering Group Jiangsu Power Design Institute Co. Ltd.Nanjing 210098China

Steps are distinctive features for estimating the movement of the upper and lower block of ***,studies about the influence of steps as a special type of discontinuity on cracking behaviors and strength of rock masses are *** this research,rock-like samples with steps and preexisting flaws were *** height h and the inclination angle of gentle slope of the stepαwere set to different *** shear tests were conducted on these samples under different normal *** experimental results reveal that the inclination angle of the gentle slope of the stepα,step height h,and normal stress have an influence on the strength,crack initiation,and crack propagation of the *** experimental results show that crack behaviors and shear strength were affected by step inclination anglesαand step height *** the normal stress increases,the improvement of the strength of samples with a large step height is larger than that of samples with a small step height,the improvement of the strength of samples withαof 10°is larger than that of samples withαof 0°and-10°.The discrete element method was used to simulate the shear *** results show five different types of displacement vectors,which can be used to determine whether the cracks are tensile cracks or shear *** above conclusions can provide help for estimating mechanical properties and failure modes of rock masses with steps of different geometries.

关键词： Step Preexisting flaw Direct shear test Crack behavior Shear stress Numerical test

Simulation of methane adsorption in diverse organic pores in shale reservoirs with multi-period geological evolution

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International Journal of Coal Science & Technology 2021年第5期8卷 844-855页

作者： Shangbin Chen chu zhang Xueyuan Li Yingkun zhang Xiaoqi Wang Key Laboratory of Coalbed Methane Resources and Reservoir Formation Process of the Ministry of Education China University of Mining and TechnologyXuzhou 221116China School of Resources and Geoscience China University of Mining and TechnologyXuzhou 221116China

In shale reservoirs,the organic pores with various structures formed during the thermal evolution of organic matter are the main storage site for adsorbed ***,in the process of thermal evolution,the adsorption characteristics of methane in multi type and multi-scale organic matter pores have not been sufficiently *** this study,the molecular simulation method was used to study the adsorption characteristics of methane based on the geological conditions of Longmaxi Formation shale reservoir in Sichuan Basin,*** results show that the characteristics of pore structure will affect the methane adsorption *** adsorption capacity of slit-pores for methane is much higher than that of cylindrical *** groove space inside the pore will change the density distribution of methane molecules in the pore,greatly improve the adsorption capacity of the pore,and increase the pressure sensitivity of the adsorption *** the variation of methane adsorption characteristics of different shapes is not consistent with pore size,all pores have the strongest methane adsorption capacity when the pore size is about 2 *** addition,the changes of temperature and pressure during the thermal evolution are also important factors to control the methane adsorption *** pore adsorption capacity first increases and then decreases with the increase of pressure,and increases with the increase of *** the early stage of thermal evolution,pore adsorption capacity is strong and pressure sensitivity is weak;while in the late stage,it is on the contrary.

关键词： Adsorption mechanism Shale reservoir Diverse pores Multi-period geological evolution Thermal evolution

Application of Visible/Near-Infrared Spectroscopy and Hyperspectral Imaging with Machine Learning for High-Throughput Plant Heavy Metal Stress Phenotyping:A Review

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Plant Phenomics 2023年第4期5卷 657-672页

作者： Yuanning Zhai Lei Zhou Hengnian Qi Pan Gao chu zhang School of Information Engineering Huzhou UniversityHuzhou 313000China College of Mechanical and Electronic Engineering Nanjing Forestry UniversityNanjing 210037China College of Information Science and Technology Shihezi UniversityShihezi 832003China

Heavy metal pollution is becoming a prominent stress on *** contaminated with heavy metals undergo changes in external morphology and internal structure,and heavy metals can accumulate through the food chain,threatening human *** heavy metal stress on plants quickly,accurately,and nondestructively helps to achieve precise management of plant growth status and accelerate the breeding of heavy metal-resistant plant *** chemical reagent-based detection methods are laborious,destructive,time-consuming,and *** internal and external structures of plants can be altered by heavy metal contamination,which can lead to changes in plants'absorption and reflection of ***/near-infrared(V/NIR)spectroscopy can obtain plant spectral information,and hyperspectral imaging(HSI)can obtain spectral and spatial information in simple,speedy,and nondestructive *** 2 technologies have been the most widely used high-throughput phenotyping technologies of *** review summarizes the application of V/NIR spectroscopy and HSI in plant heavy metal stress phenotype analysis as well as introduces the method of combining spectroscopy with machine learning approaches for high-throughput phenotyping of plant heavy metal stress,including unstressed and stressed identification,stress types identification,stress degrees identification,and heavy metal content *** vegetation indexes,full-range spectra,and feature bands identified by different plant heavy metal stress phenotyping methods are *** advantages,limitations,challenges,and prospects of V/NIR spectroscopy and HSI for plant heavy metal stress phenotyping are *** studies are needed to promote the research and application of V/NIR spectroscopy and HSI for plant heavy metal stress phenotyping.

关键词： Infrared consuming precise