过渡和碱土金属掺杂对LaGaO3固体电解质电性能影响

采用固相反应法合成碱土金属Sr、Mg与过渡金属Fe或Co复合掺杂的LaGaO3基氧化物LSGMC和LSGMF;通过TG/DTA研究LSGMC和LSGMF的形成过程;采用直流四端子法测量样品在400℃-850℃温度区间的电导率;利用EDS和XRD等技术分析样品的微区成分和晶体结构等.结果表明,约在1000℃开始形成钙钛矿相,经1400℃烧结,获得单一正交钙钛矿结构;在测试温度范围,电导率与温度的关系符合Arrhenius方程,合成的LSGMC和LSGMF为氧离子导体;在相同温度下,Sr、Mg和Fe或Co复合掺杂氧化物LSGMC和LSGMF与仅Sr、Mg双掺杂氧化物LSGM相比具有较高的离子电导率,说明少量过渡金属Fe或Co的掺杂,有利于提高离子电导率.     

Preparation,structure and magnetic properties of (Cd1−xMnx)3As2 crystals

Diluted magnetic crystals of (Cd_1−xMn_x)₃As₂ have been obtained by recrystallization in the solid state. X-ray analysis has indicated that the structures of the crystals are of α and α″ Cd₃As₂ type, depending on the composition. The dc high magnetic field magnetization and ac and dc susceptibility measurements have been carried out in the temperature range 1.5K≤T≤340K and in magnetic fields up to 14T. The high temperature dc susceptibility data shows deviations from the Curie - Weiss law below 150K. The studies of the ac susceptibility show spin - glass transition at low temperature. Basing on our results we suggest that the long - range superexchange is the most important exchange mechanism between manganese ions in the Cd_1−xMn_x)₃As₂.     

残余应力对液压油缸缸筒承载能力影响的有限元分析

为了获得残余应力对液压油缸缸筒承载能力的影响规律,利用有限元的方法,建立了缸简的力学模型,通过计算获得了缸筒残余应力与载荷之间的关系,分析了残余应力对承载能力的影响。结果表明,残余应力在很大程度上影响着缸筒的承载能力,残余压应力可以抵消一部分载荷产生的应力,从而可以提高缸筒的承载能力,而残余拉应力刚好相反。所以适当的残余应力的存在有助于提高缸筒的承载能力。     

焊条废乳化液治理的工艺研究及设计

对天津某焊条企业乳化液处理工艺进行改造,将现有的化学破乳改为生物强化破乳。将乳化废液和企业其他废水汇集形成综合废水,采用生物强化+水解酸化+接触氧化+MBR+炭滤+消毒组合工艺对其进行处理。运行结果表明,处理出水稳定达到《城市污水再生利用景观环境用水水质》(GB/T 18921-2002)的标准,出水部分回用到生产工艺中,其余回用于厂区景观水体。改造后整个工艺运行费用降低,环境和经济效益显著提高。     

改进粒子群算法在农产品物流配送路径管理中的应用

目的 为了更加合理地进行车辆路径调度管理,提高粒子群求解车辆路径优化问题的性能。方法 提出了一种动态猴子跳跃机制的粒子群优化算法,它借助群体的动态分组,采用不同的动态惯性权重来提高算法的速度,引入猴子跳跃机制来保证全局收敛性。最后把改进算法应用到物流配送路径优化的2个实例中,同一环境下,改进算法搜寻到最优路径适应值、平均运算时间,以及求得最优解的成功次数,均优于标准粒子群优化算法。结果 结果表明,改进的算法能快速有效地确定物流配送路径。结论 改进粒子群优化算法不仅具有较快的寻优速度,而且也提高了算法的收敛性,保证了寻优质量,因此具有很大的应用价值。     

Adsorption and desorption of gaseous sorbates on a bidispersed particle with Freundlich isotherm: I. Theoretical analysis

A model for the sorption of gases onto a single sorbent particle is developed in this paper. Important features incorporated in the model are macropore and micropore diffusional resistances, non-linear (Freundlich) isotherm on the macropore surface, variable particle geometry and external mass transfer resistance. Simulations of the adsorption and desorption dynamics are examined to determine the effects of isotherm non-linearity, particle geometry, macro-void capacity and γ (the ratio of macropore to micropore diffusional resistances). The effect of γ on the adsorption and desorption concentration profiles (in the macropore and micropore) is also shown. The range of validity of the bimodal diffusion control model (as well as its macropore and micropore control asymptotes) with respect to γ, is delineated. Furthermore, the asymmetry between desorption and adsorption (which is dependent on isotherm non-linearity and γ) is investigated, showing that it is not valid to apply the same criteria for micropore control to desorption, as one would apply to adsorption.     

ABO3型固体电解质La1-xSrxGa1-yMgyO3-α制备与导电性

用固相反应法合成La0.8Sr0.2Ga0.85Mg0.15O2.825(LSGM2015)和La0.8Sr0.2Ga0.75Mg0.25O2.775(LSGM2025)固体电解质,利用XRD、EDS、直流四电极法、SEM等现代测试手段对LSGM2015和LSGM2025的成分、晶体结构、、离子导电性及显微组织等进行研究.实验结果表明:合成的LSGM2015和LSGM2025均属正交晶系,具有钙钛矿结构,样品纯度较高,基本上无杂相;其电导率与温度的关系服从Arrhen ius方程,均表现出离子导电特征.LSGM2015和LSGM2025的离子迁移活化能(Ea)相近且较低(<1 eV),在试验温度范围内LS-GM2015的离子导电性明显高于LSGM2025,低价金属Sr、Mg的适量掺杂有利于电导率的提高.     

Hygrothermal ageing effects on the static fatigue of glass/epoxy composites

A study of the effects of water ageing on the static fatigue behaviour of unidirectional glass/epoxy composites is presented. The failure mechanisms associated with fatigue damage were investigated under three-point bending loading. Depending on the ageing temperature, two failure features were identified: either fibre microbuckling on the compressive side of the specimen, or progressive cracking on the tensile side. Microbuckling has been found to be related to the reversible plasticization of the epoxy matrix, as measured by dynamic mechanical thermal analysis. On the other hand, tensile failure was associated with an irreversible weakening of the fibres and interfaces at elevated ageing temperatures. Some similarity is identified between damage processes in static and dynamic bending fatigue.     

基于协调控制的双丝脉冲焊系统

“十一五”铁路、电力、能源投资建设情况 “十一五”期间,我国将进行多项重大基础设施建设,仅国家在铁路新线建设和电网建设方面的投资就将达到2万多亿元。此外,航空业期盼多年的大型飞机研制项目即将上马,第二条西气东输管线也有望启动。数万亿元的投资无疑给铁路、电力、能源等行业的上市公司带来巨大的发展机遇。     

基于HSS模型的基坑开挖对近邻地铁影响数值分析

随着城市轨道交通网络的不断扩大,城市深基坑工程大多邻近地铁区域.基坑开挖将导致周围土体产生附加位移,当土体位移过大时,就会对邻近结构物产生不利影响,因此开展基坑开挖对邻近地铁隧道区域和车站安全性影响的分析研究具有重要的现实意义.以天津某地铁车站明挖基坑工程为例,运用有限元软件Plaxis 3D分析基坑开挖对邻近隧道区间...