热力学相图计算技术在闪速燃烧合成氮化硅铁中的应用

将热力学相图计算技术应用于Si-Fe-O-N体系,以评估由FeSi75粉闪速燃烧合成氮化硅铁的条件和目标产物。结果表明:将闪速燃烧温度控制在1200～1500℃之间较为适宜,此时平衡态产物中除主要含有Si3N4以外,还有一定量的Fe与Si间化合物和少量稳定的SiO2存在。此计算结果与实际试验结果吻合良好。     

压裂泵往复密封性能及机理研究

根据流体动压润滑理论，对压裂泵柱塞密封摩擦副的润滑机理进行了理论分析。在排出和吸入行程，柱塞密封摩擦副均能满足流体动压润滑的条件，即在柱塞与密封界面上能形成并保持一定厚度的油膜润滑密封，从而达到减小摩擦提高寿命的目的；建立了摩擦界面油膜厚度和泄漏量的计算公式。利用有限元法理论，对密封圈的压力沿轴向的分布规律、泄漏量与压力变化关系进行了模拟计算。对往复密封圈沿轴向压力分布、泄漏量随压力变化进行了测试；试验结果表明，建立的计算模型具有较高的计算精度，揭示了压裂泵的密封机理。     

New Environment-Friendly Approach for Bastnasite Metallurgic Treatment (I): Extraction of Tetravalent Cerium from Sulphuric Acid Medium with Di(2-ethylhexyl) Phosphoric Acid

Bastnasiteisamainsourceofrareearthproducts inwhichCeO2/REOisabout50%.Atpresent,a cidity leachingcombinedwithalkali conversion method[1]iscommonlyusedinthebastnasitetreat ment.Thismethodisunfriendlytotheenvironment becausetheradioactiveelementofthoriuman…     

桥带电阻的数值模拟研究

从理论上对桥带电阻进行了数值计算，研究了桥带尺寸、环境温度及各种因素与桥带电阻的关系，为确定桥带电阻的控制参数和质量标准提供科学依据．     

Mobility Influences on the Capacity of Wireless Cellular Networks

Capacity has always been a major concern in wireless networks. This letter studies the impact of mobility on the overall system capacity in wireless cellular networks. In this letter, we present a simple system model which we developed to capture the inherent relationships among system capacity, new call blocking probability, handoff dropping probability, call terminating probability, and bandwidth utilization rate. We investigate the complex relationship between mobility and capacity‐related parameters. Through simulation, we demonstrate that mobility has a significant impact on capacity and is reversely proportional to the bandwidth reserved for handoff traffic.     

Iterative finite element model of nonlinear viscoplastic analyses for blended granular porous media

The iterative finite element model, in which an element is used to represent a single particle, is generated to analyze the global behavior of multiple-material aggregates of materially nonlinear viscoplastic particles. The generalized Maxwell model is used to define four types of specific nonlinear viscoplastic materials, which are the elasto visco-plastic matter with linear viscosity, the plasto visco-plastic material with linear viscosity, the elasto visco-plastic media with nonlinear viscosity, and the plasto visco-plastic media with nonlinear viscosity. The theory and relevant penalty iterative algorithm are developed to analyze the four representative mixed granular systems consisting of materially nonlinear viscous particles. To verify precision of stress calculation, solutions of an axis-symmetric radial flow problem are compared with results of the literature and they are in a great agreement. The results present here provide significant insight into the fundamental behavior of granular media under compaction conditions, including prediction of the overall aggregates stress-strain response.     

医院空调设计的几点体会

空调系统应用于普通房间可能引起空调病 ,应用于医院时此问题将更为突出 ,本文对此类建筑在空调系统设计中应重视的有关问题进行了初步探讨     

内管注水泥固井工具的研究与分析

内管注水泥技术是针对大尺寸套管和表层套管固井的特点及特殊要求而采用的一种固井技术，具有省时、替量少等特点，在现场得到大量推广应用。内管注水泥器是内管固井技术的关键工具，其性能好坏直接影响到固井质量。对各种内管注水泥固井工具的结构及特点分别进行了分析研究，并就其发展方向提出建议。     

煤直接液化中SO2-4 /ZrO2固体酸的催化作用

以二苯甲烷、苯乙醚为煤的模型化合物,以四氢萘(THN)为溶剂,进行中高压加氢液化实验,结合产物的气相色谱和质谱分析,考察了SO2-4/ZrO2固体酸对煤直接液化的催化作用及加氢液化机理.实验结果表明,SO2-4/ZrO2固体酸对模型化合物的转化具有良好的催化活性,与非催化液化相比,400 ℃、H2初压5 MPa、30 min时二苯甲烷的转化率由8.96%提高到61.75%,且模型化合物的存在促进了溶剂THN的转化,上述条件下THN的转化率也达到10.92%;模型化合物及THN的转化主要包括氢解、异构、氢转移及烷基化等反应;SO2-4/ZrO2固体酸的催化作用主要为酸催化的离子反应机理,增强催化剂的酸性有利于煤的催化液化.