基于VXI总线仪器协议的测试系统硬件构成与数据采集方法

基于VXI总线测试技术，结合铁道部九五技改重点投入项目，研制出了基于VXI总线的交流传动内燃机车出厂试验台测试系统。讨论该测试系统硬件结构中所涉及到的VXI总线仪器协议及测试系统所使用主要模块的功能。     

关于VXI总线模块设计的思考

VXI总线测试系统是在八十年代后期产生并兴起的测试总线系统,广泛应用于航天、航空、军事、汽车工业等领域中.在VXI总线C尺寸多通道同步数采模块的设计方法和虚拟仪器构建方面做了一些分析.     

基于虚拟仪器技术的电测计量标准室

虚拟仪器技术是基于PC的仿真技术,VXI总线是当前性能较成熟的测控系统机箱底板总线之一。文章主要介绍在NI公司推出的图形化编程环境中采用即插即用协议的VISA(Virtual Instrument Software Architecture)方式将各基于VXI总线的仪器模块通过编程定义成具有不同功能的虚拟仪器,从而构建一个基本具有传统电测计量标准室功能的虚拟测控系统。文章基于虚拟仪器技术从硬件和软件平台构成角度出发,阐述基于虚拟仪器技术的电测计量标准室的原理框图,关键技术和功能特点。     

虚拟仪器技术和发展趋势

本文叙述了基于工业标准计算机总线技术,结合硬件和软件的用户自定义的虚拟仪器解决方法。介绍了PXI,VXI,SCXI,GPIB和网络等等硬件和软件技术,及在计量测试、测控技术及仪器仪表领域的应用,随着网络的发展,信息技术是虚拟仪器应用的一个主要领域。     

虚拟仪器驱动程序设计

在虚拟仪器系统中，仪器驱动程序是连接仪器与用户界面的桥梁，是系统设计的一个关键。本文结合自行开发的基于VXI总线的多通道数字输入／输出模块仪器驱动程序，讨论了符合VXI总线即插即用规范的仪器驱动程序的一般设计方法，该方法对于其他的虚拟仪器驱动程序的开发具有参考与推广价值。     

基于VXI总线的无人机综合测试系统的设计

利用VXI总线技术开放式的体系结构和模块化的自动测试技术的优势,结合国产无人机现状,研发了基于虚拟仪器的综合检测系统.该系统具有通用性好、扩展性强、标准化程度高的特点.文章给出了测试仪的硬件配置和在LabWindows/CVI环境下的软件模块化设计方案及实现方法.     

关于VXI总线仪器系统校准问题的讨论

VXI总线仪器系统是由VXI总线模块组成的集成仪器系统，用软件流程控制完成确定的技术任务，多数为自动化测试仪器系统(ATS或ATE)，可以完成测量、控制、数据处理、信息管理等全部或部分功能。从VXI总线技术诞生之日起．便获得了广泛应用。它可以是一个大型实验系统，也可以是一个生产线上的过     

虚拟仪器测试技术应用综述

介绍了虚拟仪器测试技术的基本概念、虚拟仪器结构和虚拟仪器总线技术，讨论了面向对象的虚拟仪器测试系统的开发与虚拟仪器测试系统软件设计。     

基于VXI总线技术的智能电路板的仿真测试

本文对带微处理器电路板进行了仿真测试方法研究 ,并结合实际给出一种基于VXI总线技术及微处理器仿真测试技术的自动测试系统 ,论述了该系统的总体结构 ,介绍了硬件、软件的功能及测试方法     

基于VXI总线的交流传动内燃机车试验台测试系统研制

本论文利用基于VXI总线的测试技术与虚拟仪器技术 ,结合铁道部九五技改重点投入项目 ,研制出了首台交流传动内燃机车出厂试验台测试系统。论文从测试系统方案的论证、传感器的选型与配置、硬件系统的选型与配置、软件系统的开发以及对系统进行一些抗干扰措施防护等。经过近两年的试验台运行 ,证明该系统是高精度和高可靠性的     

Similarity solutions for slender dry patches with thermocapillarity

The lubrication approximation is used to investigate slender dry patches in an infinitely wide film of viscous fluid flowing steadily on an inclined plane that is either heated or cooled relative to the surrounding atmosphere. Four non-isothermal situations in which thermocapillary effects play a significant role are considered.Similarity solutions describing a thermocapillary-driven flow with a dry patch that is widening or narrowing due to either gravitational or surface-tension effects on a non-uniformly heated or cooled substrate are obtained, and examples of these solutions, when the substrate temperature gradient depends on the longitudinal coordinate according to a general power law, are presented. When gravitational effects are strong, the solution contains a free parameter, and for each value of this parameter there is a unique solution representing both a narrowing pendent dry patch and a widening sessile dry patch, whose transverse profile has a monotonically increasing shape. When surface-tension effects are strong, the solution also contains a free parameter, and for each value of this parameter there is both a unique solution representing a narrowing dry patch, whose transverse profile has a monotonically increasing shape, and a one-parameter family of solutions representing a widening dry patch, whose transverse profile has a capillary ridge near the contact line and decays in an oscillatory manner far from it.Similarity solutions are also obtained for both a gravity-driven and a constant-surface-shear-stress-driven flow with a dry patch that is widening or narrowing due to thermocapillarity on a uniformly heated or cooled substrate. The solutions in both cases contain a free parameter, and for each value of this parameter there is a unique solution representing both a narrowing dry patch on a heated substrate and a widening dry patch on a cooled substrate, whose transverse profile has a monotonically increasing shape.     

Pd-C高温共晶点复现装置研制

主要针对Pd-C高温共晶点复现装置的组成进行介绍,其中包括复现用高温均热炉炉体、温度控制系统、真空泵、充气保护装置、水冷系统、复现用的石墨坩埚、二等B型标准热电偶和Pt-Pd热电偶等。针对石墨坩埚的灌注和共晶点复现过程进行了描述,根据复现的试验数据进行了相应的分析。     

The surface tension of HFC refrigerants and mixtures

The surface tension of the refrigerants R32, R125, R134a, R143a and R152a, as well as the binary refrigerant mixtures R32-R125, R32-R134a, R125-R134a, R125-R143a, R125- R152a, R143a-R134a and R134a-R152a, and the commercially available ternary mixtures R404A and R407C was measured across the temperature range from −50 to 60°C using a measuring unit based on the capillary rise method. Different formulations for calculation of the surface tension of the binary and ternary mixtures on the basis of the surface tension of the pure refrigerants were tested. With an approach based on mass proportions in the mixture, a good correspondence between the measured and calculated values was achieved.     

Statistical Analysis of Macromolecular Chains in the Space Filled by Nanoparticles

The paper presents a combination of worm-like chain numerical models and one with a finite set of nano-particles. The primary objective of the models was to analyze the distribution of space in a system filled by particles. Information on the distribution of space was compared to properties of chains inside the set of particles. The set of nanoparticles was constructed with a tool generating a finite set of particles that is randomly distributed in a given space. The particles have a prescribed volume fraction and uniform size. First, the proportions of chains and particles were compared. The length of chain was expressed in terms of end-to-end length. It was then compared to the size of gaps between two particles. The volume of chain was compared to the volume of space delimited by the particles. Next, a set of 10,000 random chains was generated and these were introduced into the particle set. The contact of a chain with the surface of a particle resulted in the special structural elements of the chain: a chain connecting two different particles, a loop which begins and ends at the same particle, a part of a chain which is completely adhered to the particle surface, a chain attached to a particle with one free end, as well as completely free chains. The chains were classified under three classes: chains which were not in contact with particles, chains which were in contact with one particle, and chains which were in contact with two or more particles. A statistical representation of each class is presented. The contact between chain and particle can influence macroscopic properties such as those that are elastic.     

A cost minimisation model for joint production and maintenance planning under quality constraints

In this paper, integrated planning of production, imperfect maintenance and process inspections in a multi-machine system is investigated. This system consists of parallel machines which deteriorate with time and they may shift from a primarily in-control state to a degraded state with a higher defective rate or to a failed state. Maintenance scheduling corresponds to a discrete time age-based imperfect maintenance with a large number of maintenance alternatives. Process inspections are considered to detect the current state of the system. Detecting a deteriorated condition initiates the quality check of the related sub-lots, rework of defective items and a process adjustment that brings the machine in its normal conditions. Production planning includes a capacitated lot-sizing problem with multiple products. We propose a joint approach that coordinates the decisions of the three functions, where the objective function minimises the total cost. Evaluation of costs and interacting factors is presented and two heuristic methods are proposed to solve the problem. The results of the joint model are compared to a non-integrated method and a sensitivity analysis is conducted.     

Rapid inversion of eddy current data for conductivity and thickness of metal coatings

A feature-based method that determines the thickness and electrical conductivity of a coating on a metal plate from the change in the frequency-dependent impedance of an eddy-current probe coil is presented. Recently a least-squares solution of this problem was presented, which, however, requires approximately 20 CPU minutes on a DEC 5000 work station for the analysis of each set of measurements. We show that a feature-based approach can reduce the time to a few seconds on the same processor. We start by showing that a three-parameter scaling of the resistive component of the impedance change vs. frequency leads to a simple and nearly universal curve. Consequently these parameters provide a simple and compact way of expressing the data. Next, we show that the three scaling parameters can be used to construct a look-up table that determines the conductivity and thickness of the coating. Finally, we test the method using experimental data.     

The X-HPD—conceptual study of a large spherical hybrid photodetector

We present the results of a conceptual study demonstrating the feasibility of a large spherical hybrid photodetector with central anode. A prototype tube with 208 mm diameter and an anode in form of a metallic cube has been fabricated. In the final version of the so-called X-HPD concept the anode will be a scintillator cube with plated faces and a small photodetector to readout the bottom. The bialkali photocathode covers three quarters of the sphere surface. Combined use of this cathode in transmissive and reflective mode leads to effective quantum efficiency values exceeding those obtained in conventional hemispherical PMT designs. Further features of the concept are a photoelectron collection efficiency approaching 100% and a photon amplification in the scintillator crystal leading to a distinct single photoelectron signal.

Using a custom built electron accelerator based on a CsI transmissive photocathode, LSO and YAP block crystals in geometries adapted to the anode of an X-HPD have been tested with single photoelectrons in the 10–30 keV energy range. The scintillation light was readout with a conventional PMT or a Si-PM. More than 30 photoelectrons per incident electron could be detected with the PMT.     

不可约Z-矩阵最小特征值的数值算法

首先给出了不可约非负矩阵最大特征值的上下界。然后利用相似变换构造了一列相似矩阵,从而得到不可约非负矩阵最大特征值的逐步压缩的一列上下界,其极限为所要求的最大特征值。最后利用Z-矩阵与非负矩阵的关系,给出了计算不可约Z-矩阵最小特征值的一个新算法。理论上给出了收敛性证明。该算法迭代过程简单,不用计算逆矩阵,从而计算量小,占用内存少。数值实验的结果表明该算法具有可行性和有效性。     

Influence of a Jump in the Power of Laser Radiation on Its Measurement

Simulation and investigation of the effect of an isolated jump on realization of the unit of power of laser radiation and dissemination of the size of the unit are considered. Results are obtained by means of a newly developed algorithm that characterizes the behavior of the mean value of a signal and the standard deviation of a system as functions of the parameters of a jump in the power of laser radiation and the length and amplitude of the jump. If information concerning the time when a jump occurs is available, the proposed algorithm makes it possible to take into account how a jump affects the ultimate result of a measurement.     

Myopic vs. far-sighted behaviours in a revenue-sharing supply chain with reference quality effects

In this paper, we consider a dynamic supply chain where a manufacturer produces and distributes a featured product through an exclusive retailer to end consumers. The manufacturer decides the product quality and wholesale price, while the retailer sets the retail price in the presence of a revenue-sharing contract and consumers’ reference quality effects. The objective of this study is to investigate the impacts of myopic behaviour regarding the reference quality on the product quality and pricing strategies and profits of both members. Our results suggest that the manufacturer’s myopia leads to a higher quality, higher price strategy and a higher quality–price ratio which benefits consumers. Meanwhile, relative to the far-sighted behaviour, myopia results in a more quality-sensitive but less price-sensitive market demand. What’s more, we find that the manufacturer is apt to act in a far-sighted way, but the retailer isn’t always willing to cooperate with a far-sighted manufacturer. Taking myopic strategies for both members is likely to gain a high profit of the whole supply chain for a relatively high marginal contribution of product quality on demand and a relatively low revenue-sharing proportion.