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Rolling Force and Rolling Moment in Spline Cold Rolling Using Slip-line Field Method

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Chinese Journal of Mechanical Engineering 2009年第5期22卷 688-695页

作者： zhang Dawei LI Yongtang fu Jianhua zheng Quangang School of Materials Science and Engineering Taiyuan University of Science and Technology Taiyuan 030024 China School of Materials Science and Engineering Northwestern Polytechnical University Xi ＇an 710072 China Qingdao Cool Rolling Technological Research and Development Center Qingdao 266100 China

Rolling force and rolling moment are prime process parameter of external spline cold rolling. However, the precise theoretical formulae of rolling force and rolling moment are still very fewer, and the determination of them depends on experience. In the present study, the mathematical models of rolling force and rolling moment are established based on stress field theory of slip-line. And the isotropic hardening is used to improve the yield criterion. Based on MATLAB program language environment, calculation program is developed according to mathematical models established. The rolling force and rolling moment could be predicted quickly via the calculation program, and then the reliability of the models is validated by FEM. Within the range of module of spline m=0.5-1.5 mm, pressure angle of reference circle α=30.0°-45.0°, and number of spline teeth Z=19-54, the rolling force and rolling moment in rolling process （finishing rolling is excluded） are researched by means of virtualizing orthogonal experiment design. The results of the present study indicate that： the influences of module and number of spline teeth on the maximum rolling force and rolling moment in the process are remarkable; in the case of pressure angle of reference circle is little, module of spline is great, and number of spline teeth is little, the peak value of rolling force in rolling process may appear in the midst of the process; the peak value of rolling moment in rolling process appears in the midst of the process, and then oscillator weaken to a stable value. The results of the present study may provide guidelines for the determination of power of the motor and the design of hydraulic system of special machine, and provide basis for the farther researches on the precise forming process of external spline cold rolling.

关键词： external spline cold rolling slip-line field method rolling force rolling moment

Faceted interfaces: a key feature to quantitative understanding of transformation morphology

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npj Computational Materials 2016年第1期2卷 44-57页

作者： Wen-zheng zhang Xin-fu Gu fu-Zhi Dai School of Materials Science and Engineering Tsinghua UniversityBeijingChina Institute for Materials Research Tohoku UniversitySendaiJapan Science and Technology on Advanced functional Composite Laboratory Aerospace Research Institute of Materials and Processing TechnologyBeijingChina

Faceted interfaces are a typical key feature of the morphology of many microstructures generated from solid-state phase ***,prediction and simulation of this faceted morphology remain a challenge,especially for systems where irrational orientation relationships(ORs)between two phases and irrational interface orientations(IOs)are *** terms of structural singularities,this work suggests an integrated framework,which possibly encompasses all candidates of faceted *** structural singularities are identified from a matching pattern,a dislocation structure and/or a ledge *** resultant singular interfaces have discrete IOs,described with low-index g’s(rational orientations)and/orΔg’s(either rational or irrational orientations).Various existing models are grouped according to their determined results regarding the OR and IO,and the links between the models are clarified in the integrated *** of defect types as far as possible in a dominant singular interface often exerts a central restriction on the *** irrational IO is usually due to the elimination of dislocations in one direction,i.e.,an O-line *** methods using both three-dimensional and two-dimensional models for quantitative determinations of O-line interfaces are reviewed,and a detailed example showing the calculation for an irrational interface is *** association between structural singularities and local energy minima is verified by atomistic calculations of interfacial energies in fcc/bcc alloys where it is found that the calculated equilibrium cross-sections are in a good agreement with observations from selected alloys.

关键词： transformation rational interface

对实施《全国普通高校体育教育本科专业课程方案》的担忧与建议

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体育学刊 2004年第5期11卷 7-9页

作者：李德甫张正萍河北师范大学体育学院河北石家庄050016 河北经贸大学体育部河北石家庄050061

《全国普通高校体育教育本科专业课程方案》(以下简称《课程方案》)于2004年开始实施。在2003年11月华北、东北协作区普通高校体育院系年会上32所学校体育院系的院长、主任对实施《课程方案》表示出了许多令人担忧的问题,通过对与会专... 详细信息

《全国普通高校体育教育本科专业课程方案》(以下简称《课程方案》)于2004年开始实施。在2003年11月华北、东北协作区普通高校体育院系年会上32所学校体育院系的院长、主任对实施《课程方案》表示出了许多令人担忧的问题,通过对与会专家意见的整理和分析,提出了实施《课程方案》的建议。

关键词：体育教育专业课程方案高校

Liver fibrosis： mechanisms of immune-mediated liver injury

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Cellular & Molecular Immunology 2012年第4期9卷 296-301页

作者： Ruonan Xu zheng zhang fu-Sheng Wang Liver Disease Research Center for Biological Therapy Beijing 302 Hospital Beijing China

Liver fibrosis and its end-stage consequence, cirrhosis, represent the final common pathway of virtually all chronic liver diseases. Research into hepatic stellate cell activation, imbalance of the extracellular matrix synthesis and degradation and the contribution of cytokines and chemokines has further elucidated the mechanisms underlying fibrosis. furthermore, clarification of changes in host adaptive and innate immune systems has accelerated our understanding of the association between liver inflammation and fibrosis. Continued elucidation of the mechanisms of hepatic fibrosis has provided a comprehensive model of fibrosis progression and regression. This review summarizes the current concepts of improvements that have been made in the field of fibrosis.

关键词： cirrhosis hepatic stellate cell liver fibrosis

Deselenization and detellurization of precious-metal ore concentrates by swelling oxidizing roasting and successive alkaline leaching

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International Journal of Minerals,Metallurgy and Materials 2017年第2期24卷 147-155页

作者： fu-yuan zhang Ya-jie zheng Guo-min Peng School of Metallurgy and Environment Central South University Changsha 410083 China Henan Zhongyuan Gold Smelter Co. Ltd. Sanmenxia 472000 China Key Laboratory of Comprehensive Utilization of Gold Resource Sanmenxia 472000 China

A new technique of swelling oxidizing roasting and alkaline leaching was proposed for deselenization and detellurization of pre- cious-metal ore concentrates. Alkali-metal and alkaline-earth-metal chlorides and carbonates were preliminarily selected as swelling agents. The roasting removal rate and alkaline leaching rate of selenium and tellurium were investigated, and NaCl was selected as an appropriate swelling agent. furthermore, the effects of various factors on the selenium gasification rate and leaching rate of selenium and tellurium were investigated. The results show that the selenium gasification rate reaches 88.41% after swelling oxidizing roasting for 2 h at 510~C using an NaC1 dosage coefficient of 100 and a sulfuric acid dosage coefficient of 1.3; the amorphous elemental tellurium is completely transformed into TeO2. The roasted product is subjected to alkaline leaching using a 100 g/L NaOH solution, which results in a selenium leaching rate of 10.51%, a total selenium removal rate of 98.92%, and a tellurium leaching rate of 97.64%. In the alkaline leaching residue, the contents of selenium, tellurium, gold, platinum, and palladium are 0.7825%, 5.492%, 8.333%, 0.2587%, and 1.113%, respectively; the precious metals are enriched approximately sixfold.

关键词： ore treatment precious metals roasting leaching selenium removal tellurium removal

Structures and energetics of semicoherent interfaces of precipitates in hcp/bcc systems:A molecular dynamics study

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Journal of Materials Science & Technology 2021年第8期67卷 50-60页

作者： Jin-Yu zhang fu-Zhi Dai Zhi-Peng Sun Wen-zheng zhang Key Laboratory of Advanced Materials(MOE) School of Materials Science and EngineeringTsinghua UniversityBeijing 100084China Science and Technology of Advanced functional Composite Laboratory Aerospace Research Institute of Materials&Processing TechnologyBeijing 100076China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of ChinaChengdu 610041China

α/β(hcp/bcc)interfaces are of great importance in the microstructure development and the mechanical properties of titanium and zirconium *** work contributes to the study of interface energetics and interfacial structures of the precipitate in the hcp/bcc system based on a simulation study using molecular statics(MS)and molecular dynamics(MD).The input orientation relationship(OR)was calculated based on the O-line *** on the energy of the interfaces containing the invariant line(IL),two preferred facets were determined by the Wulff construction,which explained the observed orientations of the habit plane(HP)and the side facet(SF).The deviation of the observed precipitate morphology from the equilibrium shape was discussed in terms of interface *** structures of the interfaces surrounding a three-dimensional(3 D)precipitate,including the preferred facets and the end face,were obtained at the atomic *** simulated dislocation structures and atomic structures in these interfaces are in good agreement with those of the experimental observations for Ti-Cr alloys.A method was suggested for modifying the O-cell structure with the guidance of the relaxed structure,yielding consistency between the calculated dislocation structure based on the generalized O-element approach and the simulation results.

关键词： Interface Misfit dislocation Precipitate

Long afterglow yellow luminescence from Pr^(3+) doped SrSc_(2)O_(4)

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Journal of Rare Earths 2022年第4期40卷 567-571,I0003页

作者： Xiaoyan fu Shenghui zheng Yanfeng Meng Wenzhi Sun Hongwu zhang College of Materials Science and Engineering Xiamen University of TechnologyXiamen 361024China School of Chemistry and Material Sciences Ludong UniversityYantai 264025China Key Lab of Urban Pollutant Conversion Institute of Urban EnvironmentChinese Academy of SciencesXiamen 361021China

A yellow emitting long afterglow luminescence material SrSc_(2)O_(4):Pr^(3+)was successfully prepared by solid state reaction ***_(2)O_(4):Pr^(3+)phosphor shows a long afterglow luminescence peak at about 495,545,621,630 and 657 nm,respectively,corresponding to the f–f transitions of Pr^(3+).The afterglow chromaticity coordinates of SrSc_(2)O_(4):1 at%Pr^(3+)were calculated to be(0.35,0.41),indicating that the afterglow emission is close to the light of yellow ***,the afterglow luminescence of the optimal sample doped by 1 at%Pr^(3+)can persist for over 3 *** thermoluminescence results suggest that there are three types of traps with depth of 0.61,0.69 and 0.78 eV exiting for all the samples,which are produced by the addition of Pr^(3+)*** trap density of SrSc_(2)O_(4):1 at%Pr^(3+)is the maximum when the incorporation of Pr^(3+)ions reaches 1 at%,which thus results in the longest afterglow *** the results indicate that SrSc_(2)O_(4):Pr^(3+)can be a potential candidate of novel long afterglow phosphors.

关键词： Long afterglow luminescence SrSc_(2)O_(4):Pr^(3+) Traps Long afterglow luminescent mechanism Rare earths

Protist Interactions and Seasonal Dynamics in the Coast of Yantai, Northern Yellow Sea of China as Revealed by Metabarcoding

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Journal of Ocean University of China 2020年第4期19卷 961-974页

作者： fu Yingjun zheng Pengfei zhang Xiaoli zhang Qianqian JI Daode School of Ocean Yantai UniversityYantai 264003China Key Laboratory of Coastal Environmental Processes and Ecological Remediation Yantai Institute of Coastal Zone ResearchChinese Academy of SciencesYantai 264003China Center for Ocean Mega-Science Chinese Academy of SciencesQingdao 266071China

Facilitated by the high-throughput sequencing(HTS)technique,the importance of protists to aquatic systems has been widely acknowledged in the last ***,information of protistan biotic interactions and seasonal dynamics is much less known in the coast ecosystem with intensive anthropic *** this study,year-round changes of protist community composition and diversity in the coastal water of Yantai,a city along the northern Yellow Sea in China,were investigated using HTS for the V4 region of 18S *** interactions among protist groups were also analyzed using the co-occurrence *** analyses showed that Alveolata,Chlorophyta,and Stramenopiles are the most dominant phytoplanktonic protists in the investigated coastal *** community composition displayed strong seasonal *** abundant families Dino-Group-I-Clade-1 and Ulotrichales_X had higher proportions in spring and summer,while Bathycoccaceae exhibited higher ratios in autumn and *** diversities(Shannon and Simpson)were the highest in autumn and the lowest in spring(ANOVA test,P<0.05).Nutrients(SiO42−,PO43−),total organic carbon(TOC),and pH seemed to drive the variation of alpha diversity,while temperature,PO43−and TON were the most significant factors influencing the whole protist ***-variance network analyses reveal frequent co-occurrence events among ciliates,chlorophytes and dinoflagellate,suggesting biotic interactions have been induced by predation,parasitism and mixotrophy.

关键词： coastal zone biotic interaction high-throughput sequencing northern Yellow Sea protist diversity seasonal dynamic

Anchor single atom in h-BN assist NO synthesis NH_(3):a computational view

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Rare Metals 2022年第10期41卷 3456-3465页

作者： Chao-zheng He Ya-Xing zhang Jia Wang Ling fu Institute of Environment and Energy Catalysis Shaanxi Key Laboratory of Optoelectronic Functional Materials and DevicesSchool of Materials Science and Chemical EngineeringXi’an Technological UniversityXi’an710021China College of Resources and Environmental Engineering Tianshui Normal UniversityTianshui741001China

Synthesis of ammonia gas through environmental protection and low-cost electrocatalysis is one of the ways to solve the current human energy ***,through the study of density functional theory(DFT),a series of transition metal single atoms are embedded in the defect-containing h-BN to construct a TM@B_(2) N_(2)(TM=Ti-Zn,Nb-Ag) two-dimensional *** activation effect of these single-atom catalysts on NO molecules and the electrochemical performance of catalyzing NO reduction reaction(NORR)were *** reaction pathways are studied in detail,and competition between hydrogen proton and ammonia(NH3) oxidation with NORRs is also *** the16 transition metal atoms we studied,the intercalation of Pb atom into h-BN has the best catalytic *** reaction rate-limiting potential of NORR is only 0.55 eV,and the surface HER reaction and ammonia oxidation can be effectively *** is hoped that our research can further promote the application of h-BN in the field of catalysis and provide some guidance for experimental workers in the field of ammonia synthesis.

关键词： Density functional theory(DFT)calculations Nitric oxide reduction reaction Electrocatalytic activity Ammonia Single-atom catalysts