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一种有限元结构动态计算的过渡元──9节点板壳-实体元 被引量:1
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作者 李树庭 《振动与冲击》 EI CSCD 北大核心 1994年第4期56-61,共6页
本文利用三维八节点实体元和八节点由壳超参数单元构造出一种9节点板壳-实体过渡元。该元具有三维实体和曲壳的双重属性。可用于一些板壳-实体结构的动态计算。由于该元要求与之相联的实体,板壳元网络划分简单,单元结点数较少,动... 本文利用三维八节点实体元和八节点由壳超参数单元构造出一种9节点板壳-实体过渡元。该元具有三维实体和曲壳的双重属性。可用于一些板壳-实体结构的动态计算。由于该元要求与之相联的实体,板壳元网络划分简单,单元结点数较少,动态计算精度能满足工程精度要求,所以该元具有一定的实用价值。 展开更多
关键词 有限 过渡元 固有频率 板壳-实结结构
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用于热应力分析的体-壳过渡元
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作者 尹泽勇 杨治国 +1 位作者 杨德辉 陆波 《应用力学学报》 CAS CSCD 北大核心 1995年第2期115-119,共5页
以往体-壳过渡元中采用的一般三维应变状态下的初始热应变表达式,与过渡元规定的变形方式不一致。本文利用“相应体元”算出15节,点过渡元热膨胀时因壳面上法线不伸长引起的应变,以此修正一般三维初始热应变,给出过渡元初始热应... 以往体-壳过渡元中采用的一般三维应变状态下的初始热应变表达式,与过渡元规定的变形方式不一致。本文利用“相应体元”算出15节,点过渡元热膨胀时因壳面上法线不伸长引起的应变,以此修正一般三维初始热应变,给出过渡元初始热应变的正确表达式。本文方法扩大了体-壳过渡元的应用范围。 展开更多
关键词 体-壳过渡元 热应力 相应体 弹性力学
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采用壳体应变—应力状态的体—壳过渡元
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作者 尹泽勇 杨治国 陆波 《航空学报》 EI CAS CSCD 北大核心 1993年第10期B477-B483,共7页
由于初始热应变表达式不当及不能完全实现泊松效应,以往建立的体-壳过渡元会导致不真实的大应力。本文采用壳体应变-应力状态作为过渡元中的应变应力状态,给出一种新的15节点体-壳过渡元列式,从而解决了以上两个方面的问题。算例表明了... 由于初始热应变表达式不当及不能完全实现泊松效应,以往建立的体-壳过渡元会导致不真实的大应力。本文采用壳体应变-应力状态作为过渡元中的应变应力状态,给出一种新的15节点体-壳过渡元列式,从而解决了以上两个方面的问题。算例表明了这种过渡元的有效性与实用性。本文方法既适用于其它类型的过渡元,对于其它处理体-壳组合结构的方法也有重要参考价值。 展开更多
关键词 体-壳过渡元 热应力 泊松效应
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用改进的三维等参奇异元计算应力强度因子
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作者 王柏松 贺寅彪 《核科学与工程》 CSCD 北大核心 1991年第2期129-133,117,共6页
本文给出了一种改进的三维等参奇异元并证明了该奇异元在一系列与裂纹面垂直的面上具有r^(-(1/2))的奇异性。本文还将过渡元的概念和 Williams 公式应用于三维问题。实例计算表明上述奇异元及计算方法具有较好的精度。
关键词 奇异 过渡元 应力强度因子
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锡对改善铅-钢层状复合材料结合界面及其性能的影响 被引量:4
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作者 梁方 竺培显 +2 位作者 周生刚 孙德林 马会宇 《中国有色金属学报》 EI CAS CSCD 北大核心 2012年第11期3094-3099,共6页
通过引入锡元素作为过渡组元来解决铅-钢界面的结合问题。借助于扫描电镜及能谱仪研究铅-锡-钢层状复合材料的界面形貌及界面处元素分布;通过三点弯曲试验及线性伏安扫描曲线分别研究铅-锡-钢层状复合材料的抗弯强度和电化学性能。结果... 通过引入锡元素作为过渡组元来解决铅-钢界面的结合问题。借助于扫描电镜及能谱仪研究铅-锡-钢层状复合材料的界面形貌及界面处元素分布;通过三点弯曲试验及线性伏安扫描曲线分别研究铅-锡-钢层状复合材料的抗弯强度和电化学性能。结果表明:利用真空热压扩散烧结法可制备界面冶金式结合的铅锡钢层状复合材料;铅-锡-钢层状复合电极与传统二元Pb-1%Ag电极相比,其析氧电位负移80 mV,催化活性提高了8倍,抗弯强度提高了44.1%。 展开更多
关键词 铅-锡-钢层状复合材料 过渡 界面 真空热压扩散烧结
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FEM modeling of softened base metal in narrow-gap joint by CMT+P MIX welding procedure 被引量:2
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作者 舒凤远 吕耀辉 +4 位作者 刘玉欣 徐富家 孙哲 何鹏 徐滨士 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第6期1830-1835,共6页
A required finite element method(FEM) model applicable for narrow gap CMT and CMT+P MIX welding was established based on the interactions between arc,base metal and filler metal.A novel method of simplifying wire f... A required finite element method(FEM) model applicable for narrow gap CMT and CMT+P MIX welding was established based on the interactions between arc,base metal and filler metal.A novel method of simplifying wire feeding pulses and heat input pulses was supposed under the conduction of equivalent input.The method together with composed double-ellipse heat sources was included in the model.The model was employed in the investigation of thermal cycling and the identification of the softened zone of AA7A52 base plates.Low-frequency behavior emerged in the form of low-cooling rate sects,which were not expected under experimental conditions.The softened zone including the quenched zone and averaging zone of the base plate was much wider internal the base plate than that close to the surfaces.The reliability of the predictions in thermal cycling was supported by infrared imaging test results of the thermal cycle process. 展开更多
关键词 cold metal transferring finite element method equivalent input low-cooling rate sects softened zone
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硼氢化立体选择性还原制备拉米夫定的研究 被引量:1
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作者 徐伟明 黄卓豪 +3 位作者 李万梅 游金宗 蒋善会 章鹏飞 《杭州师范大学学报(自然科学版)》 CAS 2014年第4期370-372,共3页
在对核苷类抗病毒药物拉米夫定的制备进行文献综述的基础上,提出一条立体选择硼氢化还原的合成路线合成了拉米夫定.反应中形成的六元环过渡态结构有效抑制消旋化,使得反应过程工艺简单,产品纯度好,收率高,完全符合作为原料药的使用要求.
关键词 拉米夫定 硼氢化 立体选择 还原 过渡
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CH_3SH与ClO反应机理的量子化学及电子密度拓扑研究 被引量:1
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作者 樊红敏 李晓艳 +2 位作者 曾艳丽 孟令鹏 郑世钧 《河北师范大学学报(自然科学版)》 CAS 北大核心 2008年第2期213-217,227,共6页
采用B3LYP方法和6-311G(d,p)基组找到了CH3SH与ClO反应的6个可能的反应通道,得到了各反应通道的反应物、中间体、过渡态和产物的优化构型.对反应过程中若干关键点进行了电子密度拓扑分析,讨论了反应进程中键的断裂、生成和化学键的变化... 采用B3LYP方法和6-311G(d,p)基组找到了CH3SH与ClO反应的6个可能的反应通道,得到了各反应通道的反应物、中间体、过渡态和产物的优化构型.对反应过程中若干关键点进行了电子密度拓扑分析,讨论了反应进程中键的断裂、生成和化学键的变化规律.找到了该反应的"结构过渡态"和"结构过渡区",非平面四元环状结构过渡态的发现拓展了原来对环状结构过渡态的定义. 展开更多
关键词 反应机理 电子密度拓扑分析 环状结构过渡
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债群理论的分析与应用──市场经济下关于债务清理的新思路
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作者 王少南 韩崇华 《山东法学》 1995年第2期27-30,共4页
债群理论的分析与应用──市场经济下关于债务清理的新思路王少南,韩崇华当前我国的社会经济生活中,普遍存在着债务问题,这一现象,不仅严重地阻碍了经济的持续、快速发展,使资源得不到合理配置,而且还伴生了诸如谁欠债多谁就掌握... 债群理论的分析与应用──市场经济下关于债务清理的新思路王少南,韩崇华当前我国的社会经济生活中,普遍存在着债务问题,这一现象,不仅严重地阻碍了经济的持续、快速发展,使资源得不到合理配置,而且还伴生了诸如谁欠债多谁就掌握主动权,谁讨债多谁就有经济效益等畸... 展开更多
关键词 分析与应用 流关系 群理论 债务清理 债务问题 清欠机构 债权债务关系 中心 过渡元 场经济
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Molecular Simulation Study on Interaction of Thiophene Sulfides with Transition Metals 被引量:6
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作者 LiuYujian LongJun ZhouHan ZhuYuxia DaZhijian 《China Petroleum Processing & Petrochemical Technology》 SCIE CAS 2003年第4期43-49,共7页
The computer molecular simulation technique was applied to study the chemisorption of thiophene and tetramethylthiophene as the model sulfides on the simple oxides and complex oxides of some transition metals as the c... The computer molecular simulation technique was applied to study the chemisorption of thiophene and tetramethylthiophene as the model sulfides on the simple oxides and complex oxides of some transition metals as the catalytic materials. The study disclosed that the thiophene sulfides could enter into chemisorption with metal oxides such as VO, ZnO, NiO and Zn-Al-spinel. This interaction could lead to thiophene molecular structure deformation to be in an activated adsorption state, which could help to promote the conversion of thiophene sulfides in the course of catalytic cracking. The VO with a valence of 2 could provide relatively strong selective adsorption sites for the conversion of thiophene sulfides to apparently transform the molecular structures and electron cloud states of such heterocyclic sulfur compounds such as thiophene and tetramethylthiophene into an activated adsorption state. The effect of this interaction was more pronounced with respect to tetramethylthiophene. 展开更多
关键词 catalytic cracking sulfur reducing mechanism THIOPHENE molecularsimulation transition metal oxides VANADIUM
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Finite element analysis on impact of foundation treatment in bridgehead transition section upon bridge piles
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作者 ZHENG Wei DU Lizhi WANG Yong 《Global Geology》 2011年第4期254-258,共5页
In order to decrease relative settlement, foundation treatment plays an extremely important role in bridgehead transition section, especially, the situation of building the bridge piles firstly, and then processing pi... In order to decrease relative settlement, foundation treatment plays an extremely important role in bridgehead transition section, especially, the situation of building the bridge piles firstly, and then processing piles. On the basis of engineering practice, the authors analyzed the influence of foundation treatment on bridge piles in bridgehead transition section by finite-element method (FEM). This research has positive significance in predicting displacement of bridge pile, directing construction of foundation treatment, and improving quality of engineering and so forth. 展开更多
关键词 foundation treatment finite element analysis bridge pile bridgehead transition section
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Impacting Factors of Elemental Mercury Re-emission across a Lab-scale Simulated Scrubber 被引量:11
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作者 武成利 曹晏 +1 位作者 董众兵 潘伟平 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2010年第3期523-528,共6页
Elemental mercury(Hg^0)re-emissions from slurries and solutions were evaluated in a lab-scale simulated scrubber.Oxidized mercury(Hg^2 +)standard solution was injected into the simulated scrubber at a desired rat... Elemental mercury(Hg^0)re-emissions from slurries and solutions were evaluated in a lab-scale simulated scrubber.Oxidized mercury(Hg^2 +)standard solution was injected into the simulated scrubber at a desired rate to simulate absorbing and dissolving of Hg^2 +in the flue gas across wet flue gas desulfurization(WFGD)systems. PS analytical mercury analyzer was used to continuously determine Hg0re-emission concentrations in the carrier gas from the scrubber.Sulfite ion in the slurry of CaSO3 was validated to reduce Hg ^2+to Hg^ 0,while no Hg ^0 re-emission occurred from slurries of CaSO4 and CaO.Transitional metal ions with low chemical valence such as Fe^2 +,Pb ^2+,Ni ^2+, AsO2^-and Cu ^+were used to prepare solutions with concentration levels of mmol·L^-1.Reduction reaction of Hg^2 +to Hg 0was observed from these solutions.Reduction capabilities for the different transitional metal ions in the solutions were:Pb^2 +〉Cu ^+〉Fe^ 2+〉 AsO2^-〉Ni ^2+. 展开更多
关键词 simulated scrubber elemental mercur-y re-emission impacting factors SULFITE transitional metal ions
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Screening-Dependent Study of Superconductivity in 3d-Transition Metals Binary Alloys Superconductors
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作者 Aditya M.Vora 《Communications in Theoretical Physics》 SCIE CAS CSCD 2009年第3期533-539,共7页
In the present article, we report the screening-dependent study of the superconducting state parameters (SSPs), viz. electron-phonon coupling strength A, Coulomb pseudopotential μ^*, transition temperature TC, iso... In the present article, we report the screening-dependent study of the superconducting state parameters (SSPs), viz. electron-phonon coupling strength A, Coulomb pseudopotential μ^*, transition temperature TC, isotope effect exponent a, and effective interaction strength No V of 3d-band transition metals binary alloys superconductors have been made extensively in the present work using a model potential formalism and employing the pseudo-alloy-atom (PAA) model for the first time. Five local field correction functions proposed by Hartree (H), Taylor (T), Ichimaru-Utsumi (IU), Farid et al. (F) and Sarkar et al. (S) are used in the present investigation to study the screening influence on the aforesaid properties. The present results of the SSPs obtained from H-screening are found in qualitative agreement with the available experimental data wherever exist. 展开更多
关键词 PSEUDOPOTENTIAL superconducting state parameters (SSPs) 3d-band transition metals binary alloys superconductors
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Study on the Reaction Behavior of Some Trinuclear Complexes of Transition Metals: [Fe_2M(μ_3-O) (μ-O_2CCH_3)_6(H_2O)_3]·xH_2O by the Method of Probe Reaction of Acetic Acid
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作者 HE Ling-Jie CHEN Bo +5 位作者 CAI Su-Hua WANG Yan-Ming ZHOU Wen-Bo ZHANG Lin-Na (Fujnin Institute of Research on the Structure of Matter,the Chinese Academy of Sciences, Fuzhou, Fujian 350002, China)XIE Qing-Shan (Present address:Shishi Organizing Committee ,Sh 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 1998年第5期365-371,共7页
The reaction behaviors of the title complexes have been studied in thesystem of dinitrogen gas by means of in situ IR. It has been found that some activefragments created at some stage of the thermal decomposition pro... The reaction behaviors of the title complexes have been studied in thesystem of dinitrogen gas by means of in situ IR. It has been found that some activefragments created at some stage of the thermal decomposition process of the complexes.enable.the acetic acid both obtained from the ligand of the complexes and introducedfrom outside to convert to acetone by decarboxylation. Their optimum reaction temperatures are of 240~270℃ for [Fe2MnO(O2CCH3),(H2O)3], 290~320 C for [Fe3Q(O2CCH3)6(H2O)3], 300~330℃ for [Fe2CoO(O2CCH3),(H2O)3] and 320~ 350℃for [Fe2NiO(O2CCH3)6(H2O)3], indicating the lowering sequence of the activity of active species. At the same time it has been shown that this activity may come from thejoined contributions of both the coordinating capability of the hetero-metals in the complexes and their structural factors. On the basis of the TGA, DTA and EI-MS data,the composition of the active fragments has been tentatively inferred as [Fe2MnO(O2CCH3)3-2]. 展开更多
关键词 in situ IR carboxylato complexes iron complexes manganese complexes cobalt complexes nickel complexes
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有限元-界面元混合模型及其应用
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作者 尹华伟 易伟建 刘艳 《湖南科技大学学报(自然科学版)》 CAS 北大核心 2006年第4期41-46,共6页
推导得出了一个简化过渡界面单元的单元刚度矩阵.采用界面元-有限元的混合模型来模拟三维土-结构体系,并采用一致边界来模拟波向无穷远域地基的传播作用.然后编制了一个可用于进行三维土-结构非线性地震反应分析的程序,并用该程序对一... 推导得出了一个简化过渡界面单元的单元刚度矩阵.采用界面元-有限元的混合模型来模拟三维土-结构体系,并采用一致边界来模拟波向无穷远域地基的传播作用.然后编制了一个可用于进行三维土-结构非线性地震反应分析的程序,并用该程序对一框架结构进行了考虑土-结构相互作用影响的地震反应分析.最后总结了各种非线性因素和土-结构相互作用效应对结构地震反应的影响规律.图11,参9. 展开更多
关键词 有限 界面 有限-界面混合模型 过渡界面 土-结构相互作用 一致边界 地震反应
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水助甲酰胺-H_2O_2氧化乙烯制环氧乙烷反应机理的理论研究 被引量:2
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作者 王俊芳 孙琪 王长生 《化学学报》 SCIE CAS CSCD 北大核心 2010年第8期727-732,共6页
采用MP2方法研究了甲酰胺-H2O2氧化乙烯制取环氧乙烷的反应机理.优化得到了反应物、过渡态、中间体及产物的几何构型并计算了反应势垒.研究结果表明:没有水参与时,反应需要通过四元环过渡态完成,反应势垒很高,在常温下难以进行;有水参与... 采用MP2方法研究了甲酰胺-H2O2氧化乙烯制取环氧乙烷的反应机理.优化得到了反应物、过渡态、中间体及产物的几何构型并计算了反应势垒.研究结果表明:没有水参与时,反应需要通过四元环过渡态完成,反应势垒很高,在常温下难以进行;有水参与时,在水分子的协助下,反应可以通过六元环过渡态完成,反应势垒较低,常温下反应容易进行. 展开更多
关键词 环氧化 过渡 过渡 水助
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BINAL-H试剂的高手性识别能力
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作者 段丽萍 雍胜利 《阴山学刊(自然科学版)》 2014年第3期41-45,共5页
本文主要介绍了日本名古屋大学化学系R.Noyori教授研究组发展起来的利用金属氢化物LiAlH4简称为(LAH)、轴手性(S)-或(R)-联萘酚与简单醇之间的反应制备新的手性氢化试剂BINAL-H。该还原剂具有极高的对映面识别能力且能够以可预测的和高... 本文主要介绍了日本名古屋大学化学系R.Noyori教授研究组发展起来的利用金属氢化物LiAlH4简称为(LAH)、轴手性(S)-或(R)-联萘酚与简单醇之间的反应制备新的手性氢化试剂BINAL-H。该还原剂具有极高的对映面识别能力且能够以可预测的和高光学产率地还原许多结构不同的不饱和羰基化合物。 展开更多
关键词 前手性 不对称合成 环状过渡 立体选择性
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Effect of Topology Structures on Synchronization Transition in Coupled Neuron Cells System 被引量:1
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作者 梁立嗣 张季谦 +2 位作者 许贵霞 刘乐柱 黄守芳 《Communications in Theoretical Physics》 SCIE CAS CSCD 2013年第9期380-386,共7页
In this paper, by the help of evolutionary algorithm and using Hindmarsh-Rose (HR) neuron model, we investigate the effect of topology structures on synchronization transition between different states in coupled neu... In this paper, by the help of evolutionary algorithm and using Hindmarsh-Rose (HR) neuron model, we investigate the effect of topology structures on synchronization transition between different states in coupled neuron cells system. First, we build different coupling structure with N cells, and found the effect of synchronized transition contact not only closely with the topology of the system, but also with whether there exist the ring structures in the system. In particular, both the size and the number of rings have greater effects on such transition behavior. Secondly, we introduce synchronization error to qualitative analyze the effect of the topology structure. Phrthermore, by fitting the simulation results, we find that with the increment of the neurons number, there always exist the optimization structures which have the minimum number of connecting edges in the coupling systems. Above results show that the topology structures have a very crucial role on synchronization transition in coupled neuron system. Biological system may gradually acquire such efficient topology structures through the long-term evolution, thus the systems' information process may be optimized by this scheme. 展开更多
关键词 neuron network topology configuration synchronization transition
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Borates as a new direction in the design of oxide ion conductors
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作者 Xiaohui Li Li Yang +10 位作者 Zhenyu Zhu Xiaoge Wang Pohua Chen Senchuan Huang Xianyi Wei Guohong Cai Pascal Manuel Sihai Yang Jianhua Lin Xiaojun Kuang Junliang Sun 《Science China Materials》 SCIE EI CAS CSCD 2022年第10期2737-2745,共9页
Lowering the operating temperature of solid oxide fuel cells(SOFCs)has extensively stimulated the development of new oxide ion conductors.Here,inspired by the structural commonalities of oxide ion conductors,the inabi... Lowering the operating temperature of solid oxide fuel cells(SOFCs)has extensively stimulated the development of new oxide ion conductors.Here,inspired by the structural commonalities of oxide ion conductors,the inability to accommodate oxygen vacancies in the rigid,isolated,3-fold tetrahedral rings of SrSi/GeO_(3)-based materials,and the considerable flexibility of BO_(n) polyhedra in terms of coordination number,rotation,deformation,and linkage,we report the first borate-base family of oxide ion conductors,(Gd/Y)_(1−x)Zn_(x)BO_(3−0.5x),through combined computational prediction and experimental verification.The oxygen vacancies in(Gd/Y)BO_(3)can be accommodated by forming B_(3)O_(8)units in isolated,3-fold,tetrahedral rings of B_(3)O_(9)and transported through a cooperative mechanism of oxygen exchange between the B_(3)O_(9)and B_(3)O_(8)units,which is assisted by the intermediate opening and extending of these units.This study opens a new scientific field of the borate system for designing and discovering oxide ion conductors. 展开更多
关键词 solid oxide fuel cells (Gd/Y)1−xZnxBO3−0.5x oxide ion migration mechanism borate oxide ion conductors ab initio molecular dynamics simulations
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