3D characterization of super-smooth surfaces of diamond turned OFHC copper mirrors

In this study, super-smooth surfaces of oxygen-free high-conductivity copper mirrors obtained by single point diamond turning were characterized with an atomic force microscope from the three-dimensional (3D) point of view. The machining conditions were also studied. A program developed in this study for a unified approach to 3D surface finish assessment proposed by the Commission of European Community was used to obtain the 3D parameters. In two experiments, the feed rate was changed from 0.2 to 2.0 μm per revolution and 0.3 to 3.0 μm per revolution, respectively. By 3D roughness characterization of these surfaces, the optimal feed rate was found to be 1.4 μm per revolution when the cutting depth was 1 μm or 0.9-1.2 μm per revolution at a cutting depth of 2 μm, where an S_q of 2.6 and 2.3 nm could be obtained, respectively. The suggested 3D roughness characterization parameters may include S_q, S_sk, S_ku, S_tr, S_al, S_Δq, and one functional parameter, such as S_bi.     

低能X射线在正比管内产生脉冲幅度的分布

正比管对大于2keV X射线的探测,输出的脉冲幅度分布近似高斯分布。而对低能超软X射线、紫外线,它给出的脉冲幅度分布明显偏离高斯分布。本文从实验上和理论上研究单电子和少数日电子在正比管内产生脉冲的情况。认为在低气体放大倍数时,单能软X射线在正比管内产生脉冲幅度分布是Г分布的加权总和。     

In-proces sensors for surface roughness and their applications

Potential non-contact optical methods for in-process surface roughness measurement are described, including reflected light position detection, focu     

Ultrasonic evaluation of geometrical and surface parameters of rough defects in solids

Ultrasonic measurements from rough cracks were carried out using both broad-band and narrow-band methods. An analysis is suggested to determine parameters of the crack quantitatively such as size, shape, rms surface roughness, and distribution function of the surface roughness. Ultrasonic measurements of the parameters compare very well with the actual parameters of the defect.     

碳酸盐岩储层多级注入闭合酸压技术研究与应用

本文阐述了针对陕甘宁盆地中部气田碳酸盐岩低渗储层的特点,采用系统工程方法开展的多级注入闭合酸压技术研究,介绍了利用研制的多级注入、二维及拟三维酸压设计软件模拟研究所获得的一些重要认识;提出了该项技术的现场设计原则及效果评估方法,介绍了现场应用效果。文中强调指出,对低渗及特低渗碳酸盐岩气藏,多级注入闭合酸压技术是最好的增产措施。     

On Measuring the Root-Mean-Square Value of a Finite Record Length Periodic Waveform

An analysis of the uncertainty in measuring the root-mean-square, rms or R_q, value of a periodic waveform which results from the use of a finite record length is presented. Even though the results of the analysis are somewhat as expected, i.e., that the uncertainty is inversely proportional to the number of periods in the record, the explicit relationship between the magnitude of the uncertainty and properties of the waveform does not appear to be available in the literature. The paper first presents an introductory example in terms of the reasonably well known case of bandwidth limited Gaussian waveform to introduce definitions. Following this is an analysis of the periodic waveform using the same approach. It is shown that for a large number of periods, n, in the record length, the normalized three standard deviation of the rms value is given by 3/(8πn).     

居住建筑层高的心理透视

本文从设计观念和居住观念上指出两种人的心理障碍,并试图说明只要从观念上进行更新,即使是较低的建筑层高,不但是可以接受的,而且完全有可能成为一个亲切的尺度。     

战术地地导弹爆高延时方案计算与分析

提出用摄动制导原理延时控制爆高的新方案。在末修结束时，由弹上机计算延时修正量，通过延时控制爆高，数值计算表明，该方案可以大大减小主动段各种干扰带来的误差     

测量表面粗糙度的新型光纤传感器

介绍了一种测量表面粗糙度的准直型光纤传感器。该传感器成功地消除了光纤测头到被测表面距离变动和环境的杂散光线对输出的影响,传感器光通量的计算方法可用于位移及其它反射型光纤传感器的特性分析和结构设计。     

Spin-up and Spin-Down Times of Rotational Air Flow Depended on Mean Air Velocity and Surface Roughness on Inner Surface in Cylindrical Vortex Chamber

The spin-up time TA in the spin-up process and spin-down time TD in the spin-down process of rotational air flow in the cylindrical vortex chamber with three kinds of the artificial surface roughness were investigated. One of the most different characteristics between the smooth and rough surface conditions was the spin-down time TD. Also the transient response of the tangential velocity on the spin-up process was analyzed numerically and this result was compared with the experimental results. The above stated results are reported here in detail.