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STUDY ON THE REAR CAPACITY OF DEPOSITS USING ELECTROLESS NICKEL DEPOSITION AND ELECTROPLATE CHROMIUM

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Acta Metallurgica Sinica(English Letters) 1999年第5期12卷 777-781页

作者： S.Y.Hu Collge of Mechanical engineering, China agriculture university (East Campus), Beijing 100083, China

The comparison study of the relations between the hardness, wear capacity and heat treatment temperature of the electroless nickel deposition with the electroplating deposits of chromium were conducted .The results showed that the hardness and wear capacity of the electroplate technology were superior than that of electroless in general cases, but with the raising of the heat treatment temperature, the hardness and wear capacity of the samples treated by electroless deposition technology were superior obviously than that of electroplate.

关键词： electroless nickel deposition electroplating chromium wear capacity

Construction and characterization of the transformation-competent artificial chromosome (TAC) libraries of Leymus multicaulis

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Science China(Life Sciences) 2008年第7期51卷 604-613页

作者： XU YueYu 1,2,3,ZHOU YuLei 4,5 ,SONG LinLin 6 ,ZHANG Yan 3 &ZHAO MaoLin 1 1 Beijing Agro-Biotechnology Research Center,Beijing Academy of agriculture and Forestry Science,Beijing 100097,China 2 Department of Chemistry and Chemical engineering,Hunan Institute of engineering,Xiangtan 411104,China 3 College of Life Science,Capital Normal university,Beijing 100037,China 4 College of Life Science,zhongkai university of agriculture and Technology,Guangzhou 510225,China 5 College of Grassland Science,Gansu Agricultural university,Lanzhou 730070,China 6 Department of Biology,Henan Institute of Science and Technology,Xinxiang 453003,China 1. Beijing Agro-Biotechnology Research Center Beijing Academy of Agriculture and Forestry Science Beijing 100097 China 2. Department of Chemistry and Chemical engineering Hunan Institute of Engineering Xiangtan 411104 China 3. College of Life Science Capital Normal University Beijing 100037 China 4. College of Life Science Zhongkai University of Agriculture and Technology Guangzhou 510225 China 5. College of Grassland Science Gansu Agricultural University Lanzhou 730070 China 6. Department of Biology Henan Institute of Science and Technology Xinxiang 453003 China

Transformation-competent artificial chromosome system is able to clone and transfer genes efficiently in *** order to clone genes highly tolerant to barley yellow dwarf virus(BYDV),Aphids,drought and salt from Leymus multicaulis,the two TAC genomic libraries I and II were constructed in vector pYLTAC17 and pYLTAC747H/sacB,which contain about 165000 and 236000 recombinant clones *** genome coverage of the two libraries was totally estimated to be about 3―5 haploid genome equivalents,as size selection of genomic DNA fragments was approximately from 9 to 300 *** of the genomic libraries were collected as bulked pools each containing 500 clones or so,stored in twelve 96-deep-well plates and then were gridding in triplicate onto a high-density colony hybridization filter with a 3×3 pattern using a GeneTAC?G3 arraying robot after being transferred manually into three 384-well *** 2501 and 2890 clones of Library in pYLTAC17 and in pYLTAC747H/sacB were stored individually in fourteen 384-well plates and then were automatically gridding in duplicate onto a high-density colony hybridization filter with a 6×6 pattern after a replication of *** positive clones were detected by using the probe glutahione reductase gene of *** libraries constructed here can be used to isolate genomic clones containing target genes,and to carry out genome walking for positional *** the target TAC clones were isolated,they could be immediately transferred into plant genomes with the Agrobacterium system.

关键词： Leymus multicaulis megabase-size DNA transformation-competent artificial chromosome(TAC) genomic library

随机地震作用下隧道动力响应的概率密度演化分析

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岩土工程学报 2024年第S02期46卷 21-25,37页

作者：张冬梅郭力申轶尧黄忠凯同济大学土木工程学院上海200092 青海大学土木水利学院青海西宁810016

由于地震动的随机性特征,确定性方法难以完全考虑地震动复杂随机性特点,采用随机分析方法研究隧道结构的地震响应对地下结构抗震设计具有重要的现实意义。以软土场地中圆形隧道结构为研究对象,建立典型工程场地下土体-隧道整体非线性动... 详细信息

由于地震动的随机性特征,确定性方法难以完全考虑地震动复杂随机性特点,采用随机分析方法研究隧道结构的地震响应对地下结构抗震设计具有重要的现实意义。以软土场地中圆形隧道结构为研究对象,建立典型工程场地下土体-隧道整体非线性动力相互作用分析模型,利用随机地震动模型生成符合抗震设计规范要求的非平稳地震动,将概率密度演化分析方法引入到隧道结构抗震分析中,初步探讨了隧道结构抗震性能概率密度演化特征,并以隧道倾斜角为抗震性能指标,利用概率密度演化方法求解隧道结构响应的概率密度函数,得到隧道在无破坏、轻微破坏、中等破坏和严重破坏时隧道倾斜角的超越概率。研究结果表明:隧道倾斜角在四种破坏状态下的超越概率分别为98.88%,86.10%,30.90%和3.70%;提出的概率密度演化方法可以准确获取隧道倾斜角瞬时概率信息,为研究隧道结构抗震性能的概率演化特征提供了新的思路和途径。

关键词：隧道结构概率密度演化方法随机地震动力响应超越概率

Position Control Optimization of Aerodynamic Brake Device for High-speed Trains

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Chinese Journal of Mechanical engineering 2014年第2期27卷 287-295页

作者： ZUO Jianyong LUO Zhuojun CHEN zhongkai Institute of Railway and Urban Mass Transit Tongji University

The aerodynamic braking is a clean and non-adhesion braking, and can be used to provide extra braking force during high-speed emergency braking. The research of aerodynamic braking has attracted more and more attentions in recent years. However, most researchers in this field focus on aerodynamic effects and seldom on issues of position control of the aerodynamic braking board. The purpose of this paper is to explore position control optimization of the braking board in an aerodynamic braking prototype. The mathematical models of the hydraulic drive unit in the aerodynamic braking system are analyzed in detail, and the simulation models are established. Three control functions--constant, linear, and quadratic--are explored. Two kinds of criteria, including the position steady-state error and the acceleration of the piston rod, are used to evaluate system performance. Simulation results show that the position steady state-error is reduced from around 12-2 mm by applying a linear instead of a constant function, while the acceleration is reduced from 25,71-3.70 m/s2 with a quadratic control function. Use of the quadratic control function is shown to improve system performance. Experimental results obtained by measuring the position response of the piston rod on a test-bench also suggest a reduced position error and smooth movement of the piston rod. This implies that the acceleration is smaller when using the quadratic function, thus verifying the effectiveness of control schemes to improve to system performance. This paper proposes an effective and easily implemented control scheme that improves the position response of hydraulic cylinders during position control.

关键词： high-speed train aerodynamic brake hydraulic position control optimization.

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3PRS并联机构的运动学和误差分析

制造技术与机床 2024年第9期 52-57页

作者：周文涛谢文洪李初晔李中凯华中科技大学机械科学与工程学院湖北武汉430074 中国航空制造技术研究院北京100024

为了提高机床的加工性能,研究机床的精度是关键,建立了一种用于大型复杂曲面零件高效铣削加工的3PRS并联摆角头的运动学模型,并进行了误差分析。该机构具有3个自由度,通过修正的K-G公式对其自由度进行了验证;进一步分析了该机构的位置... 详细信息

为了提高机床的加工性能,研究机床的精度是关键,建立了一种用于大型复杂曲面零件高效铣削加工的3PRS并联摆角头的运动学模型,并进行了误差分析。该机构具有3个自由度,通过修正的K-G公式对其自由度进行了验证;进一步分析了该机构的位置正逆解;在此基础上给定结构参数误差,利用开发的程序植入Ansys计算刀尖点位姿,通过两组位姿误差的比较,为后续运动学标定和误差补偿试验做准备。

关键词：并联机构运动学少自由度位置正逆解误差分析

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软土地区典型民防工程结构地震易损性分析

隧道建设（中英文） 2024年第7期44卷 1397-1409页

作者：程屹歆张冬梅黄忠凯张吾渝王寿生同济大学地下建筑与工程系上海200092 青海大学土木水利学院青海西宁810016 上海市政工程设计研究总院(集团)有限公司上海200092

为揭示软土地区典型民防工程结构地震易损性变化规律,以某单建式民防工程为例,首先,基于ABAQUS有限元平台建立土体-民防工程结构系统非线性动力分析模型;其次,进一步考虑土体非线性特性和输入地震动的不确定性,通过数值模拟揭示民防工... 详细信息

为揭示软土地区典型民防工程结构地震易损性变化规律,以某单建式民防工程为例,首先,基于ABAQUS有限元平台建立土体-民防工程结构系统非线性动力分析模型;其次,进一步考虑土体非线性特性和输入地震动的不确定性,通过数值模拟揭示民防工程结构易损性分析的合适地震动强度指标(IM);最终,建立软土地区典型民防工程结构地震易损性曲线。研究结果表明:1)峰值地面加速度(PGA)相较于其他地震动强度指标,其有效性和实用性较高,适合用于民防工程结构地震易损性分析;2)土层条件对民防工程结构的地震易损性有明显影响,土层越软,结构的易损性越高;3)软土地区民防工程结构在地震作用下有可能遭受严重破坏,随着地震动强度的增加,每种破坏状态的超越概率逐渐增加并接近100%。

关键词：民防工程软土地区地震易损性分析地震动强度指标

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轨道车辆制动副摩擦自激对车轮磨耗的影响

铁道科学与工程学报 2024年第1期21卷 48-57页

作者：宋瑞张宇航周劲松张忠凯孙丽霞沈钢同济大学铁道与城市轨道交通研究院上海201804 中铁检验认证中心有限公司北京100081 中国铁道科学研究院集团有限公司标准计量研究所北京100081 中国铁道科学研究院集团有限公司铁道科学技术研究发展中心北京100081 高速铁路与城轨交通系统技术国家工程研究中心轮轨关系实验室北京100081

轮轨周期性磨耗会加剧轮轨动态相互作用,造成车辆系统关键部件发生疲劳断裂,引起车体的异常振动,对乘坐舒适性和运行安全性有较大影响,然而先前研究很少将制动副振动与车轮磨损进行联系。为研究车轮周期性磨耗的原因,通过考虑制动单元... 详细信息

轮轨周期性磨耗会加剧轮轨动态相互作用,造成车辆系统关键部件发生疲劳断裂,引起车体的异常振动,对乘坐舒适性和运行安全性有较大影响,然而先前研究很少将制动副振动与车轮磨损进行联系。为研究车轮周期性磨耗的原因,通过考虑制动单元的自激振荡对车轮磨损的影响,建立考虑轮轨附着的列车制动系统扭转模型。利用数值方法对制动系统的振动状态进行求解,通过一些非线性理论的相关图谱(系统运动的分岔图、相图、庞加莱截面图、频谱图和时域图等),深入探究制动工况下系统的振动情况,得到制动单元内部因摩擦因数的负斜率特性引起的自激振荡对车轮磨损的影响。研究结果表明:制动系统因摩擦自激产生的不稳定运动仅在车速较低时发生,随着制动速度的降低,当车速低于12.88 km/h时,制动系统会从稳定区间进入振荡区间进而引发制动系统颤振。与此同时,制动系统的颤振会引起车轮蠕滑率的波动,进而影响轮轨间的切向力与轮轨磨损。当制动速度处于振荡区间时,车轮会出现不均匀磨损;当制动速度靠近振荡区间的临界值时,车轮磨损近似均匀;当制动速度处于稳定区间时,车轮纵向蠕滑力近似无波动,车轮不再因制动副的自激振荡产生异常磨损。最后探究了制动压力对系统运动稳定性与轮轨磨耗的影响,发现大制动压力下系统振幅增大,磨损更为明显。探究制动系统对车辆周期性磨耗的影响,可为车轮周期性磨耗机理的研究和控制措施的选用提供参考。

关键词：列车车轮制动单元自激振荡不均匀磨耗制动压力

The Deactivation of Nickel Hydroxide to Hypophosphite Electrooxidation on a Nickel Electrode

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Chinese Chemical Letters 2004年第12期15卷 1483-1486页

作者： Yue ZENG Min MO Jian Long YI Xin Jun TANG Hui Xian WANG College of Chemistry and Chemical engineering, Hunan Normal university, Changsha 410081 College of Chemistry and Chemical engineering, Tianjin university, Tianjin 300072 Department of Chemistry, Hunan agriculture university,Changsha 410128 College of Chemistry and Chemical engineering Hunan Normal University College of Chemistry and Chemical engineering Tianjin University Department of Chemistry Hunan Agriculture University

The deactivation of nickel hydroxide to the electrooxidation of hypophosphite on anickel electrode was studied by means of in situ UV-Vis subtractive reflectance spectroscopy. Theexperimental results show that when the potential is lower than-1.0 V (SCE), the surfacc on nickelelectrode is free of nickel hydroxide, on which hypophosphite is active. When the potential movespositively to about-0.75V, two absorbency bands around 300 nm and 550 nm, which were ascribedto the formation of α-nickel hydroxide, were observed, nickel is oxidized to α-nickel hydroxide.Severe deactivation of the surface occurs when the nickel surface is covered with nickel hydroxide,which separates the hypophosphite ion from nickel substrate.

关键词： Hypophosphite electrooxidation deactivation nickel hydroxide in situ UV-Vis spectroscopy.

1株具有抑制AchE活性的螃蟹内生真菌的鉴定及发酵条件优化

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中国食品学报 2013年第11期13卷 191-197页

作者：王凤舞青岛农业大学食品科学与工程学院山东青岛266109

目的:对螃蟹中分离的1株具有较高抑制AchE活性的内生真菌Pt-2进行菌种鉴定,并优化其发酵条件。方法:将Pt-2菌株进行形态学和分子生物学鉴定,并以发酵液AchE抑制率为活性指标,采用单因素和正交试验优化发酵时间、接种量、装液量、培养温... 详细信息

目的:对螃蟹中分离的1株具有较高抑制AchE活性的内生真菌Pt-2进行菌种鉴定,并优化其发酵条件。方法:将Pt-2菌株进行形态学和分子生物学鉴定,并以发酵液AchE抑制率为活性指标,采用单因素和正交试验优化发酵时间、接种量、装液量、培养温度和碳源、氮源等发酵条件。结果:经鉴定,Pt-2菌为枝孢菌属,命名为Cladosporium ***-2;其最佳发酵条件:发酵时间9 d、接种量5%、装液量200 mL(三角瓶容量500 mL)、培养温度25℃,以碳源为葡萄糖,氮源为酵母膏。在此条件下,发酵液提取物的乙酰胆碱酯酶抑制率较高,为76.32%。结论:螃蟹内生真菌具有较好的抑制AchE活性,为抗老年痴呆天然药物的开发提供了新的来源。

关键词：菌株鉴定枝孢菌属螃蟹内生真菌乙酰胆碱酯酶条件优化