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The effect of extrusion conditions on the properties and textures of AZ31B alloy

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Journal of Magnesium and Alloys 2017年第2期5卷 202-209页

作者： Qiang liu Xiao Zhou Haitao Zhou Xiaohui Fan keming liu Key Laboratory of Nonferrous Metal Materials Science and Engineering of Ministry of Education School of Materials Science and EngineeringCentral South UniversityChangsha 410083China Jiangxi Key Laboratory of Advanced Copper and Tungsten Materials Jiangxi Provincial Academy of ScienceNanchang 330029China

The effect of extrusion conditions on the tensile properties and texture of AZ31B alloy has been investigated by means of optical microscopy(OM),scanning electron microscopy(SEM),electron backscattered diffraction(EBSD)and tensile tests.It is found that the ultimate tensile strength(UTS),the yield strength(YS)and elongation(EN)of the extruded AZ31B alloy are more significantly influenced by extrusion velocities in contrast with temperature.Although the extrusion conditions are different,the {1102} texture is the chief texture in the AZ31B after extrusion.Moreover,the extrusion textures become scattered with increasing the temperatures at the same extrusion velocity.As the extrusion velocity is raised at the same temperature,the orientation density of textures increases and the separated textures become relatively concentrated.This leads to the changes of tensile properties at different extrusion conditions.©2017 Production and hosting by Elsevier B.V.on behalf of Chongqing University.

关键词： AZ31B magnesium alloy Hot extrusion Textures Properties Temperature

功能主义视角下意大利贩运人口犯罪规制的历史演进

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犯罪研究 2024年第2期 28-36页

作者：刘柯铭中南财经政法大学法学院

当代贩运人口犯罪随着商事交易的发展、国家以及各社会阶层的贫富差距的不断扩大愈演愈烈。为维持正常生计,参与人口贩运犯罪的主体逐渐增加,危及了当今以人权保障为根本的社会秩序的稳定。作为贩运人口的“重灾区”,意大利积极顺应国... 详细信息

当代贩运人口犯罪随着商事交易的发展、国家以及各社会阶层的贫富差距的不断扩大愈演愈烈。为维持正常生计,参与人口贩运犯罪的主体逐渐增加,危及了当今以人权保障为根本的社会秩序的稳定。作为贩运人口的“重灾区”,意大利积极顺应国际社会对贩运人口犯罪的打击趋势不断对相关法律制度进行补充与完善:协调宪法与刑法的价值立场达到打击犯罪的惩治效果;加大刑罚的威慑力度达到阻却犯罪发生的预防效果;内化人道主义理念达到对受害者的保障效果。打击贩运人口犯罪法律制度的发展既彰显了惩治犯罪、预防犯罪以及保障人权三要素的重要性,又表明了刑法的最终目的及其价值观念。

关键词：贩运人口犯罪功能主义人权保障

某金属带式无级变速器振动仿真分析与多工况下试验验证

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辽宁工程技术大学学报（自然科学版） 2024年第1期43卷 68-76页

作者：刘克铭蔡琳滢吴雪莹辽宁工程技术大学机械工程学院辽宁阜新123000

为分析某金属带式无级变速器(CVT)振动产生机理,采用集中参数法建立双级行星齿轮非线性扭转动力学模型,应用四阶龙格库塔方法进行动态响应求解,利用ADAMS软件进行动力学仿真,对动态响应进行验证,进行CVT振动台架试验测试。研究结果表明... 详细信息

为分析某金属带式无级变速器(CVT)振动产生机理,采用集中参数法建立双级行星齿轮非线性扭转动力学模型,应用四阶龙格库塔方法进行动态响应求解,利用ADAMS软件进行动力学仿真,对动态响应进行验证,进行CVT振动台架试验测试。研究结果表明:四阶龙格库塔方法与ADAMS动态仿真得到的动态响应结果基本一致;台架试验结果表明前进挡转速为2500 r/min时,低速挡输入轴轴向位置的振动加速度最大为0.623 m/s^(2),转速为1000 r/min时,低速挡输入轴轴向位置的加速度最大为0.309 m/s^(2);倒挡工况下,转速为2500 r/min时,倒挡输入轴轴向位置的振动加速度最大为0.703 m/s^(2),转速1000 r/min时,倒挡输入轴轴向位置的加速度最大为0.504 m/s^(2);倒挡工况下的振动加速度幅值比前进挡高12.85%;倒挡阶次谱中54.4阶和108.8阶振动信号最为明显,挡位切换过程中双级行星齿轮啮合次数增多,啮合间隙是CVT在倒挡动力传递中振动增大的主要原因。

关键词：无级变速器振动分析行星齿轮阶次分析四阶龙格库塔法非线性动力学分析

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基于学习成效的在线课程评价指标构建与实证

宿州教育学院学报 2024年第1期27卷 38-43页

作者：刘克铭辽宁工程技术大学教务处辽宁阜新123000

为保障在线课程教学质量,提高在线课程学习效果,构建以学习成效为核心的在线课程质量评价指标体系,以某高校在线课程为例,通过问卷调查分析影响在线课程质量的内部及外部因素,监控在线课程运行状态;通过学生问卷调查等方式评价在线课程... 详细信息

为保障在线课程教学质量,提高在线课程学习效果,构建以学习成效为核心的在线课程质量评价指标体系,以某高校在线课程为例,通过问卷调查分析影响在线课程质量的内部及外部因素,监控在线课程运行状态;通过学生问卷调查等方式评价在线课程教学质量,并对教学效果进行评价、跟踪、反馈;通过四个学期的实证研究,不断丰富学习资源、改进教学设计、改革教学方法,持续改善在线课程的内外部环境,学生在线课程的学习效果得到明显提升。

关键词：在线课程学习成效问卷调查教学质量评价指标

Human-robot interface based on sEMG envelope signal for the collaborative wearable robot

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Biomimetic Intelligence & Robotics 2023年第1期3卷 38-45页

作者： Ziyu Liao Bai Chen Dongming Bai Jiajun Xu Qian Zheng keming liu Hongtao Wu College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China Mechanical and Electrical Engineering College of Jinhua Polytechnic Jinhua 321016China Key Laboratory of Crop Harvesting Equipment Technology of Zhejiang Province Jinhua 321016China

Surface electromyography(sEMG)control interface is a common method for human-centered robotics.Researchers have frequently improved the recognition accuracy of sEMG through multichannel or high-precision signal acquisition devices.However,this increases the cost and complexity of the control system.Therefore,this study developed a control interface based on the sEMG enveloped signal for a collaborative wearable robot to improve the accuracy of sEMG recognition based on the time-domain(TD)features.Specifically,an acquisition device is developed to obtain the sEMG envelope signal,and 11 types of TD features are extracted from the sEMG envelope signal acquired from the upper limb.Furthermore,a dimension reduction method based on the correlation coefficient is proposed,transforming the 11-dimensional feature into a five-dimensional envelope feature set without decreasing the accuracy.Moreover,a recognition algorithm based on a neural network has also been proposed for gesture classification.Finally,the recognition accuracy of the proposed method,principal component analysis(PCA)feature set,and Hudgins TD feature set is compared,with their accuracy at 84.39%,72.44%,and 70.89%,respectively.Therefore,the results indicate that the envelope feature set performs better than the common gesture recognition method based on signal channel sEMG envelope signal.

关键词： Surface electromyography(sEMG) Gesture recognition Features extraction Wearable robot

基于ADAMS/CAR的某SUV汽车操纵稳定性仿真实验分析及优化

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辽宁工程技术大学学报（自然科学版） 2024年第3期43卷 333-341页

作者：刘克铭吴雪莹王宝来孙志扬姜长鹏辽宁工程技术大学机械工程学院辽宁阜新123000 沈阳真空技术研究所有限公司辽宁沈阳110000

操纵稳定性是车辆正常行驶时受到外界扰动后保持稳定运行或迅速恢复稳定的一种能力,对车辆安全平稳运行至关重要。为优化车辆的操纵稳定性,对某SUV汽车进行动力性分析,建立物理模型和数学模型,阐述悬架对汽车操纵稳定性的影响。采用ADAM... 详细信息

操纵稳定性是车辆正常行驶时受到外界扰动后保持稳定运行或迅速恢复稳定的一种能力,对车辆安全平稳运行至关重要。为优化车辆的操纵稳定性,对某SUV汽车进行动力性分析,建立物理模型和数学模型,阐述悬架对汽车操纵稳定性的影响。采用ADAMS/CAR进行整车建模,运用MATLAB软件对操纵稳定性评价指标进行评分。选取悬架的力学特性参数作为优化变量,以操纵稳定性评价指标的评分作为优化目标,通过对比选取最优方案。研究结果表明:NGSA-II算法对道路实验评价指标的优化效果较好,能够显著提升整车的操纵稳定性。

关键词：仿真实验操纵稳定性性能优化悬架整车建模 NGSA-II算法

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Evolution of Microstructure in a Cu-Cr in situ Composite Produced by Thermo-Mechanical Processing

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Journal of Materials Science and Chemical Engineering 2017年第7期5卷 29-35页

作者： keming liu Deping Lu Kai Fu Peilan Luo Zhikai Huang Wei Guo Jiuming Yu Jin Zou Qiang Hu Jiangxi Key Laboratory for Precision Drive and Control Nanchang Institute of Technology Nanchang China Jiangxi Key Laboratory for Advanced Copper and Tungsten Materials Jiangxi Academy of Sciences Nanchang China

This paper studied the microstructure evolution of a deformation-processed Cu-7Cr in situ composite prepared by thermo-mechanical processing. The longitudinal and transverse sectional microstructures were analyzed using an optical microscope and a scanning electronic microscope. In the longitudinal section, the initially randomly distributed Cr dendrites in the as-cast Cu-7Cr alloy were transformed into the fibres aligned parallel to the drawing axis;the Cr dendrites experienced breaking, flattening and rotating, lapping and merging, and homogenizing and refinement during thermo-mechanical processing. In the transverse section, the initially randomly distributed Cr dendrites in the as-cast Cu-7Cr alloy were changed into the curvy ribbon like fibres;the Cr dendrites underwent breaking, flattening and rotating, folding and twisting, and irregularizing and refinement during thermo-mechanical processing.

关键词： Cu-Cr in situ Composite Evolution Microstructure Thermo-Mechanical Processing

Discovery and its geological significance of the mantle- derived helium in the inclusions of the Ordovician oil-bearing reservoir rocks in the Huanghua depression,China

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Science China Earth Sciences 2004年第1期47卷 23-29页

作者： ZHANG Xiaobao XU Yongchang SUN Mingliang CHENG keming liu Wenhui LI Xiufen MA Liyuan State Key Laboratory of Gas Geochemistry Lanzhou Institute of Geology Chinese Academy of Sciences Lanzhou 730000 China State Key Laboratory of Gas Geochemistry Lanzhou Institute of Geology Chinese Academy of Sciences Lanzhou 730000 China State Key Laboratory of Gas Geochemistry Lanzhou Institute of Geology Chinese Academy of Sciences Lanzhou 730000 China Research Institute of Exploration and Development China National Petroleum Corporation Beijing 100083 China State Key Laboratory of Gas Geochemistry Lanzhou Institute of Geology Chinese Academy of Sciences Lanzhou 730000 China State Key Laboratory of Gas Geochemistry Lanzhou Institute of Geology Chinese Academy of Sciences Lanzhou 730000 China State Key Laboratory of Gas Geochemistry Lanzhou Institute of Geology Chinese Academy of Sciences Lanzhou 730000 China

The values of the helium isotopes in the inclusions of the Ordovician reservoir rocks in the Kongxi buried hill belt in the Huanghua depression were first measured and the source of helium and its geological significance were investigated in comparison with those of the helium isotopes in the conclusions in the Ordovician rocks in the Ordos basin and the Tarim basin. The input of the mantle-derived helium into the inclusions in the carbonate reservoir rocks was found from the Konggu 3 well, the Konggu 4 well, and the Konggu 7 well in the Kongxi buried hill belt. The 3He/4He and R/Ra in the conclusions in the Ordovician oil-bearing reservoir rocks in the Konggu 7 well average 2.54×10-6(3) (sample quantity, the same below) and 1.82(3), respectively. The percent of the mantle-derived helium in the inclusions of the reservoir rocks in the Konggu 7 well reaches up to an average of 23.0%(3). The age of the contribution of the mantle-derived helium to the inclusions in the Kongxi buried hill belt is in the Late Triassic or the Early Tertiary. The finding of the mantle-derived helium shows that the interaction of the deep crust with mantle and the activity of deep faults occurred, the terrestrial heat flow value was high, and mantle-derived inorganic gas pools might be formed in the Kongxi buried hill belt. The finding of the mantle-derived helium in the inclusions of oil-bearing reservoir rocks also provides a new way for researching the activity of mantle-derived matter and its associated geological problems.

关键词： oil-bearing reservoir rock, mantle-derived helium, geological significance, Huanghua depression.

Copper Removal from Molten Steel by Gasification

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Journal of Iron and Steel Research(International) 1999年第2期6卷 10-13页

作者： Li Liansheng Li Shiqi Xiang Changxiang Cao Jie liu keming Li Suqin University of Science and Technology Beijing

A novel method is proposed to enhance the gasification and removal of copper from molten steel by adding ammonium salts or urea into molten steel under normal pressure.The decopperization experiments were conducted in a molybdenum-wire resistance furnace at 1 873 K.The copper content of about 400 g of a mild steel was reduced from 0.49%(mass fraction,the same below) and 0.51% to 0.31% and 0.38% using 0.7 g of NHC1 and 0.5 g of(NH)COrespectively,while the copper content of the molten steel was reduced from 0.61%to 0.56% using 2.00 g of NHCONH.

关键词： molten steel copper removal ammonium salt