The Structure of Clusters and Jets of Pulsed Plasma Expanding into Vacuum

The space-time distribution of the basic kinetic parameters of a plasma is experimentally determined under conditions of expansion of plasma clusters and jets into vacuum. It is demonstrated that the dynamics and structure of plasmoids injected by pulsed erosion plasma accelerators of the electrothermal type are characterized by two successive stages or two modes of acceleration, namely, the Joule heating of electrons in the initial region of the path and the collisionless expansion of rarefied plasma.     

Dynamics of Vibroprotective Systems with Roller Dampers of Low-Frequency Vibrations

We study low-frequency vibrations of a vibroprotective system of solid bodies formed by a roller damper and a moving load-carrying body under the action of external harmonic excitations. The dynamic equations of combined motion of the working body of the damper over the hinged roller without sliding and the load-carrying body are deduced and numerically analyzed. A new procedure is proposed for the evaluation of the optimal parameters of adjustment of roller dampers in nonlinear systems.     

The effect of aluminium coating on elemental standards in X-ray microanalysis

The standardisation of frozen hydrated bulk biological specimens using gelatin standards is described. The relationship between corrected elemental X-ray counts and ionic concentration was found to be linear, and minimum detectable limits for each element are stated. Variations in uncorrected standard curves were found to be due to changes in aluminium coating thickness. There was an inverse relationship between coating thickness and elemental X-ray counts. The factors causing this are discussed. To avoid errors arising from inconsistent aluminium thickness, experimental material should only be compared with standards of similar aluminium net counts. This can be achieved most easily by mounting and analysing specimen and standard together.     

预测油气田产量的β模型

通过对油气田产量变化规律进行系统研究，推导建立了预测油气田产量的β模型。该模型不但可以预测油气田产量、累积产量随生产时间的变化，而且可以预测可采储量、最高年产量及其发生的时间。实例检验该模型是可信的。     

智能磁流变(RM)阻尼器的实验研究

磁流变 (MR)液是一种新型的智能材料 ,而MR阻尼器具有在外加电流作用下快速可逆地改变阻尼特性的特点。本文针对所作的MR阻尼器实验研究 ,介绍了实验过程及相关数据 ,并对其进行了分析。实验表明 :MR阻尼器具有良好的阻尼可控制特性 ,是结构消能减振控制的理想元件。     

节理岩体参数对围岩破损区影响的敏感性分析

本文针对黄河拉西瓦地下水电站工程，对节理岩体诸参数对围岩破损区范围的影响进行了敏感性分析。指出了主要敏感参数，对这些参数影响围岩破损区的趋势和可能程度进行了讨论，并对勘察和施工提出了一些意见。     

搅拌工艺对半固态Y112铝合金组织及性能的影响

采用自行研制的机械搅拌装置,研究了不同工艺参数对半固态Y112铝合金组织及性能的影响.研究表明,搅拌温度越高,搅拌速度越大,固相颗粒越细小、均匀和圆整,其抗拉强度与伸长率越高;但温度太高,固相颗粒会熔化,抗拉强度及伸长率也降低;随搅拌时间的延长,固相颗粒先变得细小、均匀和圆整,然后长大,抗拉强度、伸长率先升高后降低.     

Numerical study on PEMFC’s geometrical parameters under different humidifying conditions

Steady-state and three-dimensional simulations were carried out to study the influences of geometrical parameters on the performance of PEMFC under different hydrating conditions. Flow fields, species transport, transport of water in polymer membrane and movement of liquid water in cathode and anode porous layers were determined, in order to accomplish a complete estimation of ohmic and concentration losses of PEMFC power. The geometrical parameters were thickness of the polymer membrane, cathode catalyst layer as well as gas channel to rib width ratio. Every simulation was made under different relative humidities of inlet flows (50 and 100%) for every change of characteristic length. Results show that the influence of the geometrical parameters on ohmic and concentration losses is of considerable importance. The performance of PEMFC is seriously affected under dehydrating conditions. However, such performance may be considerably improved by using suitable geometrical parameters. Cathode and anode liquid saturation may not only affect the transport of species, but also the polymer electrolyte water content. These results show the importance of simultaneously calculating both the water absorption and desorption through the polymer electrolyte and the liquid saturation in the cathode and anode porous mediums to obtain an actual view of ohmic and concentration losses of the PEMFC performance.     

调谐质量阻尼器参数设计中的两个问题

本文以单自由度系统安装一个调谐质量阻尼器（简称TMD）为例，对抗风和抗震两类不同激励工况下TMD的参数设计问题进行了理论研究与对比分析。通过给出相对误差系数的概念，定量评价了不同的参数方法对TMD减振性能的影响程度。本文的研究为TMD的参数设计提供了理论指导。     

X射线三轴晶衍射法测量半绝缘GaAs单晶的化学配比

采用X射线三轴晶衍射法,根据As间隙原子对作为过量As在GaAs单晶材料中存在的主要形式的模型,可以无损、高精度测量半绝缘GaAs单晶的化学配比.并探讨了引起晶格变化的原因及其与熔体组分的关系,对于制备高质量GaAs单晶及其光电器件具有重要的意义.