主轴回转误差对加工影响的数学描述

就车床、镗床类机床主轴纯径向跳动和终了角度摆动所产生的加工误差进行了单因素分析，并给出了较为精确的数学表达。     

基于湿蒸汽测量的文丘里管结构优化设计方法

构建文丘里管湿蒸汽流动过程的CFD数值计算模型,对文丘里管内湿蒸汽流动过程进行研究,分析热工参数和文丘里管结构参数对湿蒸汽测量虚高系数的影响特性,获得基于湿蒸汽测量的文丘里管结构优化参数。     

Evaluation Method of Statistical Error in. Transit Time Measured with Cross-Correlation of Two Detector Signals

In the transit time method for measuring flow velocity, the cross-correlation function of two detector signals is computed; the delay time which maximizes the function gives the transit time of the fluid between the detectors. The cross-correlation function is mathematically defined for an infinite observation time, however actually it is computed based on a finite length of time. Due to this approximation, the measured cross-correlation function has a statistical uncertainty, which induces a scattering on the measured transit time.

In this paper, it is shown that the statistical error of the transit time may be expressed by using either the derivatives of correlation functions or the power spectral densities. The spectral expression has a merit of giving an intuitive understanding of the nature of the error and it can be seen that the error becomes smaller as the higher frequency components of the spectra increase. The error also becomes smaller when the coherence function has a larger value and/or the observation time extends for a longer period.

A simplified evaluation method of the error is proposed using a trapezoidal approximation for the power spectra and this method is applied to the transit time measurement by electro- magnetic-flowmeters. The evaluated statistical error closely agreed with the measured scattering.     

ESTIMATING THE STATIC STIFFNESS FOR A SPINDLE-TOOLHOLDER-TOOLING SYSTEM

This article focuses on static analysis to integrate the necessary components for the design of spindle-toolholder-tooling systems; the modeling and analysis of the systems is based on a mathematical model using a systematic approach for evaluating the static deflection at the cutting point. The analysis addresses the deflection of most of the components in the system including the spindle shaft, front and rear bearings, toolholder, cutting tool and their corresponding spindle-toolholder and toolholder-tool interfaces modeled with linear (radial) and rotational (tilting) springs. The effects of design parameters on the static performance of these systems are analyzed in order to assess the contribution and the influence of the individual system components. Computations and experimental results show that improvements can be made in the system by adjusting the aforementioned parameters. The proposed strategy is to iteratively predict the tool deflection at the tool tip using the analytical model based on the superposition appoach. The model is simple and it provides tremendous assistance to an engineer to select the proper toolholder and tool for minimum deflection.     

流量测量的意义及流量传感器的现状

随着工业生产和科学研究的发展,流量测量变得越来越重要.从分析流量测量的意义出发,进一步阐述了流量传感器的类型、原理及其特点.根据实际现状,分析了流量测量仪表的发展方向.     

多通道超声波液体流量测控系统

采用单台主机（含数据发送接口）带多路传感器，解决石油、化工等管路密集行业的流量集中测量和数据集中发送处理的问题，实现这些场合流量测量微机化、自动化。同时，解决了超声波流量计在石油、化工部门大面积推广所遇到的仪器价格偏高的问题。     

电磁流量测井方法的改进

大庆油田聚合物驱井多年来仅能得到点测氧活化和电磁流量计给出的各层注入量,由于油田属于典型的非均质湖相沉积,层内纵向孔隙突变性导致点测资料无法反映出注入剖面的概念而影响治理方案的制定.2002年对电磁流量计进行技术改进,实现了连续点测的目的并在萨南聚驱井测井85井次,获得了注入剖面的认识和层内不同韵律段的注入量数据.列举了应用该资料认识地下状况所进行的区块和单井治理见到的效果,为连续测井方法的改进提供参考.     

基于电涡流的新型靶式流量计

分析了利用电涡流效应测量靶受力后的位移进行流量检测的原理,并设计了相应的靶结构,构建了具有温度压力补偿的测量系统,最后根据流量标定实验数据,建立了流量传感器的数学模型.试验结果表明,该靶式流量计线性好,灵敏度高,且测量精度优于1%.     

基于子波变换的涡街流量传感器信号分析

长期以来 ,如何提取潜在噪声下的涡街流量信号一直是个问题。流体流速脉动 ,局部阻力 ,随机振动———所有这些因素都给解决这一问题带来难度。文章应用子波变换消噪理论 ,从软件滤波的角度分析了强噪声干扰下的涡街流量信号 ,并提出了单支重构计数方法。分析结果表明 ,这种方法对低流速流量计量效果很好 ,能够有效地扩展量程下限     

二元光学元件激光直写设备主轴速度调节的一种新方法

介绍了二元光学元件激光直写设备的精密伺服控制系统,分析了主轴伺服系统的结构与控制系统的性能要求,在二元光学元件激光直写设备中,主轴速度调节效果的好坏是决定刻划效率与精度的关键因素之一,本文提出了利用离焦信号的特点,判断出离焦信号的极值点,并计算相邻极值点之间的时间间隔,最终估算出离焦信号频带,并依据离焦信号的频带自动调节主轴速度的新方法。采用此方法可极大地提高刻划效率。