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Abstract: A PDM framework with an open structure and strong scalability for data organization is presented.The data expression paradigm with a distributed,multi-tier C/S system configuration and an object oriented STEP based data model together with exten
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文摘:产品数据管理系统的可扩展性和开放性是系统设计要考虑和解决的重要问题之一.在分析产品数据管理的需求基础上，参考STEP标准中对产品数据模型的描述和面向对象的建模方法，定义对象并建立基于对象的数据组织和管理机制，从而使系统具有一定的通用性、可扩展性和开放性. |
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Abstract: A V-bar flowmeter is introduced.The flowmaeter equipped with automatic pressure and temperature compensation and teletransmission.The operational principle,basic strucure and features of the flowmeter are described.
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文摘:介绍一种带压力、温度自动补偿的电远传楔型流量计，阐述了该流量计的工作原理、基本结构和性能特点。 |
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Abstract: A bandgap voltage reference is presented with a piecewise-linear compensating circuit in order to reduce the temperature coefficient.The basic principle is to divide the whole operating temperature range into some sub-ranges.At different tempera
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文摘:提出了一种采用分段线性补偿的方法来实现高精度带隙基准,其基本原理是将整个温度区间分为若干个子区间,在不同子区间上采用不同线性补偿函数达到最佳补偿.由于温度区间缩小,补偿误差也随之减小,从而在整个工作温度间上的补偿误差也缩小.理论上,只要温度子区间取得足够小,就可以达到任意精度.示例中将-40～120℃的温度区间仅分为三个子区间,平均温度系数就从1.5×10-5/℃减小到2×10-6/℃. |
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Abstract: A basic idea and practice method is proposed in this pap er to realize the parallel management of multi-case in a complicated system cons tructed by single-chip computers.The object is to avoid lowing CPU efficiency ca used by too many state det
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文摘:提出一种对单片机构成的较复杂系统实现多事件并行管理的基本思想和具体应用的方.其目的是避免因程序中设有过多的状态查询而造成CPU效率降低，提高系统对事件的实时响应. |
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Abstract: A brief summary of the history、status and utility of gas-engine-driven air-conditioner is introduced in this paper.
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文摘:介绍了煤气发动机驱动的空调制冷装置的发展历史、现状及其在各个方面的应用和特点等。 |
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Abstract: A buoyancy method of measure diamond fi lms density was reported.Feature of the method is quick,convenient accuracy and practical.
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文摘:本文报道了一种测量金刚石膜密度的浮力法。这种方法的特点是快速、方便、准确和实用。 |
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Abstract: A called bidirectional measurement method is introduced into measuring the rotation accuracy of super-precision air spindles in this paper.
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文摘:介绍一种测量超精密花岗石空气主轴径向回转精度的测量方法――双向转位法。 |
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Abstract: A cavity is made on both sides of weld bead.
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文摘:在焊道表面两侧作一空腔。 |
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Abstract: A characteristic of piezoresistive pressure sensor and some parameters used to compute altitude and velocity in unmanned air vehicle(UAV) are introduced.The sensor's temperature characteristic is further improved after temperature compensation,i
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文摘:主要介绍了压阻式压力传感器的特点及在无人机上用其来解算高度、速度等参数的使用情况，经过温度补偿后，使传感器的温度特性得到了进一步的改善，用单片机解算高度、速度，达到了满意的效果，同时分析了压阻式传感器的应用前景。 |
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Abstract: A class of general nonlinear neutral differential equations for its special cases are discussed.Sufficient conditions for all solutions of the equations to be oscillatory are obtained.It can be treated in the extreme limite theorem.
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文摘:在特定条件下讨论了一阶非线性中立型的微分方程振动问题,产生了一阶非线性中立型微分方程的振动准则,并用极限理论证明了该振动准则的正确性. |
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Abstract: A comprehensive critique on 10 years' architectural exploration of Yungho Chang, this essay is composed of Eight Steps of both diachronic and synchronic narrative and analysis.
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摘要：本文是对张永和十年来建筑探索的综合性评论，它由八步同为历时性和共时性的叙述、分析组成。 |
