关于积分形式的电容特性公式及其应用

本文通过三种简单方法推导出一个积分形式的电容特性公式,并着重介绍它在求电容方面的应用,从而表明该公式对求一般电容器的电容要比传统方法简便得多。

积分形式的电容特性公式的应用

利用积分形式的电容特性公式，较合理地计算非平行板电容器的电容和具有相当普遍性的同轴非平行园柱形电容器的电容．

美国与苏联棉花压缩特性公式的比较

王则楚付教授是棉花加工行业广大干部职工所熟悉的原安徽财贸学院商品学系的一名教师,现调到广州华南建设学院。王付教授在本行业工作期间,为本行业的发展作出了较大的贡献,现发表的这篇文稿,系王付教授离开棉花加工行业的告别作。王付教授虽然离开了本行业,但他仍然心系棉花加工事业,关心棉花加工事业的发展,并愿继续为棉花加工行业的发展尽自己力所能及的义务。特嘱本编辑部在发表该文时,表达他上述心情。我们在此祝愿王付教授在新的工作岗位上继续作出新的贡献。

一个性能优良的非线性最小二乘程序与水和水蒸汽高精度特性公式

本文提出了一个新的非线性最小二乘程序与水和水蒸汽高精度特性公式，可以满足汽轮机特性试验和现场在线监测精度和快捷计算的要求。结合运用计算机VB语言。

绿泥石菱镁石等混合物矿物相分辨

利用矿物中组分特征和XRD对被测物进行粗筛、高频红外碳硫法和XRF快速测试计算主成分元素定量滑石、绿泥石、菱镁石、石英混合物中各相。主要对分类和定量公式进行了研究,由公式特性导出对鉴别的判断依据,并使用之对试样进行了矿物相分类鉴别和定量。方法简便适用。

交流力矩电动机式织物卷绕控制方法

根据织物在卷绕过程中对张力速度协调控制的要求,在提出交流力矩电动机机械特性计算公式与负锥度卷绕特性计算公式的基础上,分析交流力矩电动机开环卷绕控制的适用范围及其性能,得出以卷径为变量的半闭环自校正控制方法和智能型前馈加反馈的高精度闭环卷绕控制方法。通过MatLab仿真与比较分析,验证了新型控制方法的优点。该新型控制方法能满足不同织物卷绕生产过程对卷绕控制的要求,并获得实际应用。同时还介绍了适合于上述2种新型控制方法的张力速度协调控制器技术实现方案。

非平行板电容器电容的又一算法

用传统求电容的方法求非平行板电容器的电容值时颇为繁杂,然而,应用积分形式的电容特性公式C=[∫dlε0(l)s(l)]-1计算非平行板电容器的电容时则计算简单,物理图像清晰,计算结果精确.文中应用上述积分公式求出了非平行板电容器的电容值与用经典方法所得结果完全相同.

Failure mode and dynamic response of a double-sided slope with high water content of soil

A double-sided slope with high water content in sandy clay was considered under the action of seismic load. Its failure mode and dynamic response were investigated using a hydraulic servo shaking table test. The typical characteristic of failure mode and dynamic responses of the double-sided slope were analyzed. Experimental results show that slope failure undergoes a process of progressive deformation. The slope failure mode can be explained as creep sliding landslide. AFA(Amplification Factor of Acceleration) at the surface and inner parts of the slope shows an increasing trend with the increase of relative elevation. The relationship between AFA and EAA(Excitation Amplitude of Acceleration) is nonlinear. An empirical formula is proposed to describe preferably the relationship between AFA,relative elevation and dimensionless EAA. The AFA at the middle and upper parts of the slope increases apparently with increasing EFA(Excitation Frequency of Acceleration).

Pneumatic resistance network analysis and dimension optimization of high pressure electronic pneumatic pressure reducing valve

The structure and working principle of a self-deigned high pressure electronic pneumatic pressure reducing valve (EPPRV) with slide pilot are introduced.The resistance value formulas and the relationship between the resistance and pressure of three typical pneumatic resistances are obtained.Then,the method of static characteristics analysis only considering pneumatic resistances is proposed,the resistance network from gas supply to load is built up,and the mathematical model is derived from the flow rate formulas and flow conservation equations,with the compressibility of high pressure gas and temperature drop during the expansion considered in the model.Finally,the pilot spool displacement of 1.5 mm at an output pressure of 15MPa and the enlarging operating stroke of the pilot spool are taken as optimization targets,and the optimization is carried out based on genetic algorithm and the model mentioned above.The results show that the static characteristics of the EPPRV are significantly improved.The idea of static characteristics analysis and optimization based on pneumatic resistance network is valuable for the design of pneumatic components or system.

Experimental research on breakup of 2D power law liquid film

On account of limited knowledge of the breakup of power law liquid film, the process of its disintegration and atomization was studied by using a planar liquid film. A linear stability analysis was adopted to predict the breakup characteristics of the power law film. The predicting formulas of stripping breakup length and diameter of ligament were put forward presently. Through high-speed photography and laser light sheet illumination,different breakup characteristics of flat power law film under different conditions were derived. The characteristic dimension of breakup regimes were defined and extracted. The effects of several parameters(injection pressure,ambient pressure, nozzle structure and fluid property) on the stripping breakup length and spray angle were investigated. The results revealed that increasing both the velocity of liquid film and the ambient pressure facilitated the breakup of film, reduced the stripping breakup length and enlarged the spray angle in different extents. The comparison between theoretical and experimental results was conducted to validate the feasibility of the linear stability theory.

Basic dynamic characteristics and seismic design of anchorage system

Based on some assumptions,the dynamic governing equation of anchorage system is established.The calculation formula of natural frequency and the corresponding vibration mode are deduced.Besides,the feasibility of the theoretical method is verified by using a specific example combined with other methods.It is found that the low-order natural frequency corresponds to the first mode of vibration,and the high-order natural frequency corresponds to the second mode of vibration,while the third mode happens only when the physical and mechanical parameters of anchorage system meet certain conditions.With the increasing of the order of natural frequency,the influence on the dynamic mechanical response of anchorage system decreases gradually.Additionally,a calculating method,which can find the dangerous area of anchorage engineering in different construction sites and avoid the unreasonable design of anchor that may cause resonance,is proposed to meet the seismic precautionary requirements.This method is verified to be feasible and effective by being applied to an actual project.The study of basic dynamic features of anchorage system can provide a theoretical guidance for anchor seismic design and fast evaluation of anchor design scheme.

Modeling of rotational supercavitating evaporator and the geometrical characteristics of supercavity within

In this paper,a rotational supercavitating evaporator(RSCE)was at first modeled by means of theoretical analysis approach.The geometrical characteristics of supercavity in the modeled RSCE were then studied through numerical simulations.The current research objectives consist in determination of shape of the supercavitator(which in the plane of rotation generates supercavity occupying the most volume between blades),and location of the area suitable for steam extraction by revealing the inner structure of supercavity.Analytical analysis was performed by solving empirical equations for the shape of RSCE,through which an evaluation of two-dimensional relative position of supercavity trailing edge for different shapes of the supercavitator has been realized.Numerical simulation was then carried out,by numerically solving the unsteady Navier-Stokes equations in their conservation form coupled with the Rayleigh-Plesset cavitation and Shear-Stress Transport turbulence models,for verification of the results obtained from empirical equations.Despite unreliable assumption of applicability of empirical equations we have confirmed similarity of the supercavity shapes obtained by both methods for the same RSCE.Therefore,the shape of supercavitator calculated by using empirical equations is acceptable,which provides a simple but reliable approach for design of RSCE.The inner structure of supercavity obtained by numerical simulation has indicated position and parameters for steam extraction openings for further numerical and experimental studies on the performance of RSCE.Practical application of steam or gas extraction is suggested for solving of some problems associated with cavitating pumping of cryogenic liquid.

Kronecker limit formula for real quadratic number fields (III)

For a kind of L-function of the real quadratic number fields, we prove a Kronecker limit formula which generalized a result of Hecke. And taking an example we give an interesting identity on a fundamental unit of such a field.