New multichannel electron energy analyzer with cylindrically symmetrical electrostatic field

This article discusses an electron energy analyzer with a cylindrically symmetrical electrostatic field, designed for rapid Auger analysis. The device was designed and built. The best parameters of the analyzer were estimated and then experimentally verified.     

Evaluation of an electrostatic dust removal system with potential application in next-step fusion devices

The ability to manage inventories of carbon, tritium, and high-Z elements in fusion plasmas depends on means for effective dust removal. A dust conveyor, based on a moving electrostatic potential well, was tested with particles of tungsten, carbon, glass, and sand. A digital microscope imaged a representative portion of the conveyor, and dust particle size and volume distributions were derived before and after operation. About 10 mm(3) volume of carbon and tungsten particles were moved in under 5 s. The highest driving amplitude tested of 3 kV was the most effective. The optimal driving frequency was 210 Hz (maximum tested) for tungsten particles, decreasing to below 60 Hz for the larger sand particles. Measurements of particle size and volume distributions after 10 and 100 cycles show the breaking apart of agglomerated carbon and the change in particle distribution over short timescales (<1 s).     

Suprathermal plasma analyzer for the measurement of low-energy electron distribution in the ionosphere

It is commonly believed that an energy transfer from thermal to suprathermal electrons (相似文献   

Multiple species ion energy analyzer applied to laser-induced plasma experiments

We have developed a device which employs parallel dc electric and magnetic fields in combination with an array of collectors and accompanying electronic circuits to measure simultaneously the momentum distributions of different ion species from a laser produced plasma. This diagnostic system automatically separates the ion species according to mass to charge ratio and utilizes the cyclotron motion to provide the momentum separation. The principle of operation, design configuration, and circuitry for the system are presented along with representative data obtained from a series of laser-induced plasma experiments.     

Double capacitive probe for the measurement of plasma potential in tokamak

Capacitive probe with two pins that can measure floating potential of plasma in the tokamak is described. Probe is compared with a Langmuir probe. Small probes size and short connections allow to achieve better performance.     

A first-order probabilistic logic with application to measurement representations

A first order probabilistic logic is developed and presented in both intuitive and formal terms. It is shown how it can be successfully applied to the development of probabilistic representations for the main structures and scales involved in (one-dimensional) measurement. As a part of the current debate on the nature of probability in measurement, this result provides a way for overcoming the traditional opposition between Bayesian and orthodox statistics.     

An electrostatic clamp with temperature stabilization of semiconductor wafers under plasma treatment

An electrostatic clamp (ESC) with helium supply under a wafer allows the temperature of semiconductor wafers to be stabilized during vacuum-plasma treatment (10⁻⁴–10 Pa), when there is an intensive heat flow from the plasma toward the wafer. Heat is efficiently removed from the plate toward the ESC due to the volume heat transmission through the helium supplied into a gap between the wafer and the ESC.     

基于多重小波变换的信号去噪及其在软测量中的应用

化工生产过程中采集到的数据信号通常具有随机性和非平稳性，附加了各种噪声，以至于影响数据建模的拟合效果和泛化性能。本文基于小波分析的特点，提出了一种对信号数据进行多重小波变换阈值去噪的方法。该方法可去除大部分高频随机噪声，提取真实信号，进而提高数据的置信度。将该方法与小波神经网络相结合并应用于丙烯腈聚合反应过程质量指标软测量模型中。仿真结果表明，该方法能有效恢复数据的真实性，提高数据建模的拟合精度与泛化性能。     

Curvature measurement with reflected-light microscopy and its application to fly facet lenses

Two methods for microscopically measuring the curvature of strongly curved surfaces are compared: one using a Michelson interferometer-type microscope and one using a novel reflectometrical method implemented in an epi-illumination microscope. The curvature values obtained with the two methods were very similar, but the latter proved to be by far the simplest. Curvature measurements on the front surface of the facet lenses of various dipteran flies revealed that facet lens diameter and radius of curvature are linearly related over a wide range of facet lens sizes.     

Measurement of the plasma potential with ion acoustic waves

Plasma potentials are determined from the bias of a Langmuir probe at which the ac probe current due to an externally excited ion wave vanishes.     

Radio frequency discharge with control of plasma potential distribution

A RF discharge plasma generator with additional electrodes for independent control of plasma potential distribution is proposed. With positive biasing of this ring electrode relative end flanges and longitudinal magnetic field a confinement of fast electrons in the discharge will be improved for reliable triggering of pulsed RF discharge at low gas density and rate of ion generation will be enhanced. In the proposed discharge combination, the electron energy is enhanced by RF field and the fast electron confinement is improved by enhanced positive plasma potential which improves the efficiency of plasma generation significantly. This combination creates a synergetic effect with a significantly improving the plasma generation performance at low gas density. The discharge parameters can be optimized for enhance plasma generation with acceptable electrode sputtering.     

A blind deconvolution separation of multiple sources, with application to bearing diagnostics

A method is presented, geared to separating signals from different sources which are convoluted and mixed by the mechanical systems before being measured. The method is based on an automatically operating blind deconvolution separation method, with Kurtosis of the separated signals as the measure to be maximised. The application described involves bearings diagnostics, whereas with many classical diagnostic methods, Kurtosis is traditionally one of the accepted criteria for fault detection. The method is tested on simulation and experimental cases. Results show that separation is possible even when measurements are distanced from the vibration exciting sources of the faulty bearing. Furthermore, the method eliminates the effect of structural resonances, which often causes severe problems in classical diagnostic methods.     

Comparative study of electrostatic sensors with circular and probe electrodes for velocity measurement of pulverised coal

This paper presents recent progress on the velocity measurement of pulverised coal in pneumatic pipelines using electrostatic sensors in combination with correlation signal processing techniques.A comparative study of electrostatic sensors with circular and probe electrodes was conducted on a 94 mm bore horizontal pipeline in a 4 MW furnace.The advantages and limitations of both sensors are discussed.Experimental results demonstrate that both sensors are capable of providing pulverised coal velocity measurement with excellent repeatability and dynamic response.     

粮情测控中蓝牙技术的应用探索

随着无线通讯技术的高速发展，蓝牙技术作为其中最具代表性的一种，具有灵活、快速、抗干扰能力强等特点。该文在介绍蓝牙技术概况的同时，将蓝牙技术的探索应用于粮情测控之中。     

A high-current plasma emitter of electrons based on a glow discharge with a multirod electrostatic trap

Pulsed electron guns that produce 170-mm-diameter beams with currents of up to 700 A, electron energies of 300 keV, and a pulse width of ～200 μs at a gas pressure of ～0.01 Pa are experimentally studied. Glow-discharge plasma with electron confinement in an electrostatic trap is used as the electron emitter. The trap is formed by a hexagonal prism that consists of 204 cathode rods, which are 5 mm in diameter, 200 mm in length and are spaced by 1.5 mm, as well as 780 cathode rods, which are 5 mm in diameter and 98 mm in length, the spacing between their axes amounting to 15 mm. The latter rods are inside the former system of rods. The plasma emitter fills the hexagonal prism, which is free of rods, at the trap center with a distance of 280 mm between opposite sides and a height of ～200 mm between the emissive grid connected to the anode and the trap bottom covered with 23-mm-diameter cathode disks. All the cathode rods and disks are insulated from one another and connected to the discharge power supply through TVO-2 430-Ω resistors. The current limitation in the circuit of each cathode element by a value of ～2 A at a pulse width of ～5 ms of the glow-discharge current of up to 1 kA fully excludes its glow-to-arc transitions and allows production of continuous pulsed electron beams with an energy capacity of up to 40 kJ and a uniform distribution of the current density over its cross-sectional area of ～0.025 m².     

The pressure distribution in and flow characteristics of wide-angle diffusers using perforated plates for flow control with application to electrostatic precipitators

To perform effectively, electrostatic precipitators require a highly uniform velocity distribution in the treatment zone. This requirement places particular demands on the design of the wide-angle diffuser upstream of the treatment zone. To generate satisfactory diffuser exit velocity profiles, perforated plates are installed within the diffuser. This paper provides a report of an experimental investigation of the nature of the flow generated by installing two perforated plates in the diffuser. Detailed measurements of the static pressure distribution and flow patterns are reported. The effects of altering the porosity and locations of the perforated plates on the flow and pressure loss characteristics are considered.     

Improved circuit for potential fluctuation compensation in the plasma during the electron energy distribution function measurement by a probe

An improved circuit consisting of a simple voltage follower for the measurement of electron energy distribution function in a plasma has been proposed. This circuit makes it possible to eliminate the fluctuation of plasma space potential, the deviation of dc probe voltage caused by the probe current drawing across the plasma resistance, and the attenuation of the second derivative signal during the measurement, simultaneously. Both the probe circuit considerations and the experimental results are presented.     

虚拟仪器技术在继电器测试中的应用

介绍虚拟仪器的概念,以图形化编程软件LabVIEW为软件开发平台,开发继电器动作特性测试程序,具有开发周期短、界面友好、操作简单的优点。     

非满管电磁流量计在污水测量中的应用

环境保护是我国的基本国策之一,工业污水的计量越来越引起重视.该文介绍了一种新型的专为非满管状态下的流量测量而设计的流量计,简单介绍了非满管电磁流量计的测量原理,着重描述了其独特的电容液位测量系统,分析了非满管电磁流量计在污水测量应用中的特点及优势.     

一种具有时间和空间分辨的等离子体光谱测量系统(英文)

等离子体光谱分析技术和设备作为一种非介入式测量方法,不干扰等离子体本身,在近年来得到广泛应用。随着其工业应用的增加,能够实现空间和时间分辨的光谱检测方法和装置越来越重要。因此,本文提出了一种能实现空间和时间分辨的等离子体光谱检测方法。采用中空探针法实现空间分辨光谱诊断,可以获得等离子体能量分布、等离子体内温度测量等功能。同时,本方法采用多信息同步采集触发方法,将等离子体电信号和高速摄像信息作为时间标尺,实现对等离子体瞬时状态的时间分辨分析。工业应用表明本文的方法可以很好地应用于等离子体的在线诊断。