两种变截面的高压纳秒电阻分压器

文章介绍了一种具有完全横向电容补偿功能的特殊结构的电阻分压器——扇形分压器,以及另一种同时具有横向电容补偿和减小趋肤效应功能的锥形薄壁分压器,用于测量纳秒上升沿的脉冲高电压。简述了它们的补偿原理和结构。刻度表明,它们具有良好的响应特性,并给出了它们在脉冲加速器上测到的电压波形。     

热模锻成形7075铝合金平头锥壳实验研究

采用热模锻制备７０７５铝合金导弹锥壳模拟试件，研究了锻后锻件各部位金相组织和硬度值分布情况。结果表明，采用热模锻制务的导弹锥壳模拟件在成形过程中，金属流动比较均匀，锥壳具有较均匀的组织性能。     

锥型分布器床层的起始喷流速度和相间传质

本文对气固流化床内锥型气体分布器进行了研究，在实验的基础上提出了一个能描述床层在起始喷流点附近的气体行为的的数学模型。并用此模型，利用实验数据，进一步提出了计算起始喷流速度Ｕ（ｍｓｆ）和相间质量交换系数的经验关联式。     

圆锥印刷四臂螺旋天线的分析与设计

提出了一种应用于全球定位系统(GPS)的宽波束圆极化圆锥印刷四臂螺旋天线。数值分析表明螺旋角和螺旋臂的长度是影响波瓣宽度的两个主要因素,文中给出了其变化规律。基于此,我们设计了一个中心频率为1.57542GHz的圆极化圆锥印刷四臂螺旋天线,并制作了模型天线。测试结果显示该天线在中心频率处的3dB波瓣宽度约为200°,满足半球覆盖特性;3dB轴比带宽约为0.35GHz;驻波比在1.5以下的频率范围为1.47~1.6GHz。实验结果和仿真结果吻合良好。     

锥形辊斜轧延伸工艺的实验研究

研究了采用锥形辊、导板和圆柱芯棒的斜轧延伸工艺的附加变形、滑移和螺距，并与曼式二辊斜轧延伸工艺作了比较。研究结果表明，锥形辊在变形、运动学方面具有明显的优点，金属的附加变形小，消耗的变形功少，轧管质量好。     

Axi-symmetric tube extrusion through a smooth conical or cosine die and over a conical or ogival mandrel: numerical construction of axi-symmetric slip-line fields and associated velocity fields

The numerical method of construction of axi-symmetric slip-line fields and their associated velocity fields suggested earlier for rod extrusion (Chitkara NR, Butt MA. Axi-symmetric rod extrusion through smooth conical, cosine and lat-faced dies, International Journal of Mechanical Sciences, submitted) and tube extrusion (Chitkara NR, Butt MA. Axi-synnetric tube extrusion through a flat-faced circular die: International Journal of Mechanical Sciences, 1997;39(3);341–366) is employed to construct slip-line fields and their associated velocity fields for a few cases of forward tube extrusion through smooth, rigid conical and cosine dies and over a smooth rigid conical or ogival mandrel. The computographic plots of slip-line fields and associated velocity fields are given in the form of weighted and directed velocity vectors as are the normal pressure distribution on both the die and the mandrel surfaces. The values of the non-dimensionalised mean extrusion pressures, are compared in each case with a similar case of plane strin extrusion and the results commented upon.     

Numerical analysis of flow pattern transition in a conical silo with ellipsoid particles

Gravity-driven discharge flow in conical silos is ubiquitous in manufacturing processes for numerous industries such as food, pharmaceutical and chemical industries, wherein flow pattern is the key topic to be studied. In this work, discrete element method was used to study discharge flow behaviors in a special conical silo. This work aims to understand the dynamic evolution of discharge flow pattern and establish methods for regional determination of flow pattern transition. The results indicated that both mass flow and funnel flow patterns coexist in the silo at the initial stage of discharge, and there is a definite transition process from mass flow to funnel flow. Furthermore, the flow pattern transition is revealed by the change in discharge flow characteristics. Specifically, the change in force acting on particles leads to the change of particle orientation and particle velocity field, macroscopically resulting in the flow pattern transition. Finally, based on the kinetic stress field and shear rate, the height and radial region of flow pattern transition were determined, respectively. Understanding of the flow pattern transition is useful to the design, scale-up and optimization of silos and similar structural devices.     

锥壳结构轴向刚度研究

从壳体的薄膜理论出发,推导锥壳的轴向刚度计算公式并利用有限元分析进行验证。根据公式,分析半锥角、锥壳高度等结构参数变化对轴向刚度的影响,为锥壳结构的设计提供参考。     

Experimental study conducted on a liquid-filled combined conical tank model

Elevated water tanks are often built with a superstructure vessel consisting of a truncated cone with a top superimposed cylindrical cap. Such vessels are referred to as ‘combined conical tanks’. This study is motivated by the lack of procedures for the seismic analysis and design of such structures. It reports the first experimental study conducted on a small-scale combined liquid-filled conical shell model. Shake table testing is conducted to determine the fundamental frequencies as well as the frequencies of vibration of the modes during which the cross section of the tank remains circular (cos(θ)-modes). The later are responsible for the base shear force and overturning moment acting on the tank.Results of the experiments are used to validate the assumptions employed in a previously developed analytical model for the free surface sloshing motion and a numerical model for the vibration of the liquid-shell system. In general, excellent agreements are shown between the analytical and the experimental results as well as between the numerical and the experimental findings.     

Critical load of a bilayered orthotropic elastic–plastic conical shell with the change of the shell basic surface location

The paper presents the derivation of stability equations and the comparison of critical loads for an orthotropic elastic–plastic conical shell with proper location of the shell basic surface. Prandtl–Reuss plastic flow theory is accepted in the analysis. To derive the stability equations the variational method was accepted and Ritz method was used to solve the equations. Numerical results were obtained by the use of a special iterative algorithm of the elastic–plastic analysis implemented on the PC.