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China Foundry 2021年第4期18卷 424-432页

作者： Tian-yu Liu Zhi-hao zhu Shuang Zhang Xiao-hua Min Chuang Dong School of Materials Science and Engineering Dalian University of TechnologyDalian 116024LiaoningChina School of Materials Science and Engineering Dalian Jiaotong UniversityDalian 116028LiaoningChina

In this study,α+βTi-Al-V-Mo-Nb alloys with the addition of multiple elements that are suitable for laser additive manufacturing(LAM)were designed according to a Ti-6Al-4V cluster *** formula can be expressed as 12[Al-Ti12](AlTi2)+5[Al-Ti14]((Mo,V,Nb)2Ti),in which Mo and Nb were added into the alloys partially instead of V to give alloys with nominal compositions of Ti-6.01Al-3.13V-1.43Nb,Ti-5.97Al-2.33V-2.93Mo,and Ti-5.97Al-2.33V-2.20Mo-0.71Nb(wt.%).The microstructures and mechanical properties of the as-deposited and heat-treated samples prepared via LAM were *** sizes of theβcolumnar grains andαlaths in the Nb-containing samples are found to be larger than those of the Ti-6Al-4V alloy,whereas Mo-or Mo/Nb-added alloys contain finer *** indicates that Nb gives rise to coarsenedβcolumnar grains andαlaths,while Mo significantly refines ***,the single addition of Nb improves the elongation,whereas the single addition of Mo enhances the strength of the *** simultaneous addition of Mo/Nb significantly improves the comprehensive mechanical properties of the alloys,leading to the best properties with an ultimate tensile strength of 1,070 MPa,a yield strength of 1,004 MPa,an elongation of 9%,and micro-hardness of 355 *** fracture modes of all the alloys are ductile-brittle mixed fracture.

关键词： titanium alloy laser additive manufacturing cluster-plus-glue-atom model composition design microstructure mechanical properties

Insights into the mechanism of Mo protecting CoCrFeNi HEA from pitting corrosion-A quantitative modelling study on passivation and repassivation processes

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Journal of Materials Science & Technology 2024年第15期182卷 152-164页

作者： Jing Dai hao Feng hua-Bing Li Hong-Chun zhu Shu-Cai Zhang Jin-Dong Qu Tong He Zhou-hua Jiang Tao Zhang School of Metallurgy Northeastern UniversityShenyang 110819China Key Laboratory for Ecological Metallurgy of Multimetallic Ores(Ministry of Education) Northeastern UniversityShenyang 110819China Analysis and Testing Centre Northeastern UniversityShenyang 110819China School of Materials Science and Engineering Northeastern UniversityShenyang 110819China

Mo has been widely reported as a conducive element for the corrosion resistance of massive alloy ***,the mechanism of Mo optimizing the corrosion resistance is complicated,and in-depth studies are still *** present work comprehensively and quantitatively studied the critical influ-ences of Mo on the passivation and repassivation behavior of CoCrFeNi HEA based on the dissolution-diffusion-deposition model proposed in our previous *** experimental results indicated that Mo remarkably eliminated the metastable pitting corrosion,significantly improved the breakdown potential and perfectly protected the CoCrFeNiMo_(0.2)HEA from pitting *** modelling and X-ray photo-electron spectroscopy(XPS)results both show that in the passivation process,MoO_(2)was the last product to deposit,thereby existing in the outer layer of the passive *** addition increased the Cr content by weakening the deposition of Fe_(2)O_(3)and Fe_(3)O_(4)and also improved the Cr_(2)O_(3)/Cr(OH)3 ratio by promot-ing deprotonation of Cr(OH)_(3),thus enhancing the quality of passive ***,when pitting corrosion occurred,MoO_(2),MoO_(3),and FeMoO_(4)were the first products to deposit and accelerated the repassivation process of HEA by timely covering the matrix in the pit cavity,thereby preventing further corrosion of the matrix.

关键词： High entropy alloy Modelling studies Passive films Pitting corrosion Repassivation process

Strategies for discovery and optimization of thermoelectric materials： Role of real objects and local fields

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Frontiers of physics 2018年第3期13卷 9-16页

作者： hao zhu Chong Xiao Hefei National Laboratory for Physical Sciences at the Microscale University of Science & Technology of China Hefei 230026 China

Thermoelectric materials provide a renewable and eco-friendly solution to mitigate energy shortages and to reduce environmental pollution via direct heat-to-electricity conversion. Discovery of the novel thermoelectric materials and optimization of the state-of-the-art material systems lie at the core of the thermoelectric society, the basic concept behind these being comprehension and manipulation of the physical principles and transport properties regarding thermoelectric materials. In this mini-review, certain examples for designing high-performance bulk thermoelectric materials are presented from the perspectives of both real objects and local fields. The highlights of this topic involve the Rashba effect, Peierls distortion, local magnetic field, and local stress field, which cover several aspects in the field of thermoelectric research. We conclude with an overview of future developments in thermoelectricity.

关键词： thermoelectric materials real objects local fields

Function of Palm Fiber in Stabilization of Alluvial Clayey Soil in Yangtze River Estuary

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Journal of Renewable Materials 2021年第4期9卷 767-787页

作者： Jili Qu hao zhu Department of Civil Engineering School of Environment and ArchitectureUniversity of Shanghai for Science and TechnologyShanghai200093China

Palm fiber is one of the favorable materials used in stabilization of soft soil in geotechnical engineering projects in recent years due to its nature of sustainability,no harm to the environment,biodegradability,availability and costeffectiveness in the context of widespread appeal from the world for returning to nature and protecting the earth our *** paper is aimed at exploring the mechanical performance of Shanghai clayey soil reinforced with palm *** unconfined compressive tests are carried out on samples treated with palm fibers of different lengths and contents,and the unconfined compressive strength(UCS),ductility rate(DR),secant modulus(SM),energy absorption capacity(EAC)and failure pattern(FP)of the reinforced and unreinforced samples have been analyzed with regard to their relationship with palm fiber contents and *** multiple regression,grey correlation and general correlation relationship analysis are applied to the resultant test data so as to obtain the mathematical and statistical equation of related soil *** has been concluded from the analysis that the unconfined compressive strength,ductility and energy absorption capacity of reinforced soil will increase with the increase in content and length of palm fiber,which are maximized when palm fiber content and length are 0.4%and 15 mm,*** the contrary,the secant modulus of reinforced soil decreases considerably with content and length of palm fiber as a ***,the failure pattern also changes from brittle to ductile gradually with the content and length of palm *** data provided by the analysis of reinforced soil can be referred to and used for the related geotechnical engineering in the *** the mathematical model obtained from the statistical regression is significantly meaningful because it can be used to predict the soil performance without the need for doing the additional tests,with saving in cost and ***’s more,the applic

关键词： Palm fiber Shanghai clayey soil UCS EAC multiple regression analysis

Dynamic Recrystallization Behavior of Medium Carbon Cr-Ni-Mo-Nb Steel during Hot Deformation

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Journal of Iron and Steel Research International 2015年第3期22卷 264-271页

作者： Shi-li zhu hua-zhen CAO Jian-song YE Wen-hao HU Guo-qu ZHENG School of Chemical Engineering and Materials Zhejiang University of Technology Technology Center Hangzhou Iron and Steel Group Company

Hot compression deformation behaviors of medium carbon Cr-Ni-Mo Nb steel were investigated at deformation temperatures ranging from 1223 to 1423 K and strain rates of 0.1, 1 and 5 s^-1. Dynamic recovery （DRV） and dynamic recrystallization （DRX） were observed during the hot compression deformation. For all of the samples, DRX occurred at deformation temperatures above 1323 K at different strain rates, while below 1223 K, no DRX was observed. The activation energy of the tested steel was determined as 386.06 kJ/mol. The ratio of critical stress to peak stress and the ratio of critical strain to peak strain were 0. 835 and 0.37, respectively. Kinetic equations interpreting the DRX behavior of the tested steel were proposed, and the corresponding parameters including the volume fraction and the average grain size were determined. Moreover, the microstructures induced under different deformation conditions were analyzed.

关键词： Cr-Ni Mo-Nb medium carbon steel hot deformation dynamic recrystallization

Negative Bias Temperature Instability ＂Recovery＂ under Negative Stress Voltage with Different Oxide Thicknesses

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Chinese Physics Letters 2011年第1期28卷 175-178页

作者： CAO Yan-Rong MA Xiao-hua hao Yue zhu Min-Bo TIAN Wen-Chao ZHANG Yue School of Electronical and Machanical Engineering Xidian University Xi'an 710071 School of Technical Physics Xidian University Xi 'an 710071 Key Lab of Wide Band-Gap Semiconductor Materials and Devices Xi'an 710071

Different phenomena are observed under negative gate voltage stress which is smaller than the previous degra- dation stress in PMOSFETs with different oxide thicknesses. We adopt the real time method to make a point of the drain current to study the degradation and recovery of negative bias temperature instability （NBTI）. For the device with thin oxide, recovery phenomenon appears when smaller negative voltage stress was applied, due to the more influencing oxide charges detrapping effects than the interface states. For the device with thick oxide, not recovery but degradation phenomenon comes forth. As many charges are trapped in the deeper position and higher energy level in the oxide, these charges can not be detrapped. Therefore, the effect of the charge detrapping is smaller than that of the interface states in the thick oxide. The degradation presents itself during the ＇recovery＇ time.

关键词： Electronics and devices Semiconductors

Torsional Response Analysis of Flexible Pipe Based on Theory and Finite Element Method

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China Ocean Engineering 2023年第2期37卷 190-203页

作者： LEI Qing-long zhu Xiao-hua School of Mechanical Engineering Southwest Petroleum UniversityChengdu 610500China Oil and Gas Equipment Technology Sharing and Service Platform of Sichuan Province Chengdu 610500China

As key components connecting offshore floating production platforms and subsea imports, offshore flexible pipes play significant roles in oil, natural gas, and water injection. It is found that torsional failure is one of the failure modes of flexible pipes during transportation and laying. In this paper, a theoretical model(TM) of a flexible pipe section mechanics is established, in which the carcass layer and the pressure armor layer are equivalent to the orthogonal anisotropic layers due to its complex cross-section structure. The calculation results of the TM are consistent with those of a finite element model(FEM), which can accurately describe the torsional response of the flexible ***, the TM and FEM are used to discuss the influence of boundary conditions on the torsional *** structure of the flexible pipe is stable when twisted counterclockwise. However, limiting the top axial displacement can improve the axial and radial instability of the tensile armor layer when twisted clockwise. Finally, it is recommended that the flexible pipe can be kept under top fixation during service or installation to avoid torsional failure.

关键词： flexible pipe torsional response analytical model finite element model

High Strength Electrospun Single Copolyacrylonitrile(coPAN)Nanofibers with Improved Molecular Orientation by Drawing

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Chinese Journal of Polymer Science 2021年第2期39卷 174-180,I0006页

作者： Tang-Cheng Xu Dong-hua Han Yong-Mei zhu Gai-Gai Duan Kun-Ming Liu hao-Qing Hou Department of Chemistry and Chemical Engineering Jiangxi Normal UniversityNanchang 330022China Co-Innovation Center of Efficient Processing and Utilization of Forest Resources College of Materials Science and EngineeringNanjing Forestry UniversityNanjing 210037China School of Metallurgical and Chemical Engineering Jiangxi University of Science and TechnologyGanzhou 341000China

High-performance carbon nanofibers are highly dependent on the performance of their precursors,especially polyacrylonitrile(PAN).In this work,the copolymer of PAN(coPAN)was synthesized for electrospinning.A self-assembling set-up was used for the stretching of single coPAN *** and Raman spectroscopies were used to characterize the chemical structure of coPAN *** electron microscopy(SEM)and atomic force microscopy(AFM)were used to monitor the morphology of single coPAN nanofibers under different drawing ***-tensile test was used to determine the mechanical properties of single coPAN *** results indicated that the drawing led to an increase in degree of molecular orientation along the fiber axis from 0.656 to 0.808,tensile strength from 304 MPa to 595 MPa,and modulus from 3.1 GPa to 12.4 *** research would provide fundamental information of high-performance electrospun coPAN nanofibers and offer opportunities for the preparation of high-performance carbon nanofibers.

关键词： Single nanofiber Electrospinning Polyacrylonitrile Molecular orientation Mechanical property

Sliding-mode control for a rolling-missile with input constraints

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Journal of Systems Engineering and Electronics 2020年第5期31卷 1041-1050页

作者： hua Siyu WANG Xugang zhu Yin The 802 Institute of Shanghai Academy of Space Flight Technology Shanghai 201100China School of Energy and Power Engineering Nanjing University of Science and TechnologyNanjing 210094China

This paper investigates the overload stabilization problem of the rolling-missile subject to parameters uncertainty and actuator saturation. In order to solve this problem, a sliding-mode control(SMC) scheme is technically employed by using the backstepping approach to make the dynamic system stable. In addition,SMC with the tanh-type switching function plays an important role in reducing intrinsic vibration. Furthermore, an auxiliary system(AS) is developed to compensate for nonlinear terms arising from input saturation. Finally, the simulation results provide a solution to demonstrate that the suggested SMC and the AS methodology have advantages of strong tracking capability, anti-interference ability and anti-saturation performance.

关键词： input constraint back-stepping approach sliding-mode control(SMC) auxiliary control system

A Filter Method for Nonlinear Semidefinite Programming with Global Convergence

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Acta Mathematica Sinica,English Series 2014年第10期30卷 1810-1826页

作者： Zhi Bin zhu hua Li zhu School of Mathematics and Computing Science Guilin University of Electronic Technology

In this study, a new filter algorithm is presented for solving the nonlinear semidefinite programming. This algorithm is inspired by the classical sequential quadratic programming method. Unlike the traditional filter methods, the sufficient descent is ensured by changing the step size instead of the trust region radius. Under some suitable conditions, the global convergence is obtained. In the end, some numerical experiments are given to show that the algorithm is effective.

关键词： Cone programming nonlinear semidefinite programming filter method step size globalconvergence