真空冶金用新型温度传感器及测温系统的校准

从真空冶金及热处理行业的精确生产及优质高效的整体战略出发,阐述真空冶金用新型温度传感器;探讨真空炉有效加热区测量过程中可能出现的误判及真空炉用不可拆卸热电偶在检定过程中存在的问题;详细论述了真空炉测温系统用分立元件法检定弊端;倡导采用现场整体在线校准法,以求进一步提高测温精度.     

热处理炉测温系统的选择及应注意的问题

本文从热处理行业精确程度及优质高效的整体战略出发,探讨了热处理炉测量过程中,可能出现的误判及真空炉、渗碳炉等用不可拆卸热电偶检定过程中存在的问题,详细论述了当前热处理炉用测温系统采用分立元件检定法的弊端,建议采用现场在线整体校准法,以进一步提高热处理炉的测温系统的准确性或测温精度。     

测温系统两种检定方法的比较

一套测温系统，一般由传感器(如热电偶、铂电阻等)、补偿导线和显示控制仪表3部分组成。按照国家计量检定规程对测温系统进行检定时，通常采用分别检定的方法。即对传感器、补偿导线、仪表3部分分别检定，并分别给出检定结果。经检定的各组成部分的误差都在规程允差之内，则它们可任意组成测温系统，按照误差合成定律，测温系统总的极限误差可由下式计算：Δε=±Δ21+Δ22+Δ23，其中Δε为极限误差；Δ1为热电偶极限误差；Δ2为补偿导线极限误差；Δ3为显示仪表的极限误差。例：镍铬-镍硅Ⅱ级工作用热电偶，普通级补偿导线和1.0级0～1100…     

短型热电偶测温装置的整体检定

为解决短型热电偶示值检定中 ,因参考端温度补偿难以准确测量 ,给检定结果带来的误差 ,将短型热电偶测温装置进行整体检定 ,从而解决了短型热电偶的示值检定问题。     

热电偶检定过程中的问题分析

目前,热电偶广泛应用于各种测温场所,其测温原理是基于热电效应原理,即两种不同成分的导体焊接或绞接在一起,当其两端处于不同温场时,在回路中就会产生热电势,通过测量热电势的大小从而测量出温度。为了使其测温准确,热电偶在使用一段时间后都要进行周期检定。在检定过程中常常会发现一些影响检定结果的因素,现结合检定实践,找出这些因素产生的原因以提高检定的准确性。     

采暖散热器散热量检定系统温度测试系统设计

本文在对采暖散热器散热量检定系统中温度测试系统设计过程进行介的基础上,着重对铂电阻测温系统误差引人因素及其消除方法进行了分析,最后提出了提高测温系统的测温精度的标定方法并对系统测温精度进行计算。     

新型智能真空表校验仪的研制

介绍了一种新型智能真空表校验仪的组成、测量原理和测量方法，具有简单实用的优点，适合0.4级及以下级真空表的校准检定。     

真空热处理技术培训班预告

<正>一、预计开课时间及地点:2010年6月中下旬北京(具体时间地点待定)。二、培训内容:1、真空技术基础课、真空技术绪论、真空测量、真空获得、真空系统、真空炉检漏;2、真空热处理、真空钎焊、真空烧结工艺、真空炉的结构与关键技术;3、参观:北京真空炉制造企业。     

用电位差计法检定直流测温电桥的数据处理方法

直流测温电桥检定规程中用电位差计方法检定测温电桥的数据处理方法不是很详细 ,容易引起歧义 ,有些检定员的数据处理方法甚至会得到不正确的结论。本文针对该数据处理方法谈谈自己的看法     

压力表计量基础知识讲座

8膜盒压力表的检定8.1检定依据检定的依据：JJG2023-1989《压力计量器具》国家计量检定系统表;JJG2071-2013（-2.5-2.5kPa）压力计量器具检定系统表;JJG52-2013《弹性元件式一般压力表、压力真空表和真空表》检定规程.另外,JJG573-2003《膜盒压力表》规程已作废,“膜盒压力表”规程内容已并入JJG52-2013.     

Scanning iron temperature lidar for mesopause temperature observation

We introduce a new method for temperature profile measurements in the mesopause region in the altitude range from 80 to 105 km. A frequency-doubled narrowband alexandrite laser is used to scan the iron resonance line at 386 nm. The isotopic shifts of the iron isotopes and the laser bandwidth are derived by the measurement itself. Neglecting the minor isotopes results in large temperature errors up to 28 K. We discuss the derived temperatures in comparison with results of our potassium temperature lidar. The iron lidar-derived temperatures have typically a statistical error of 0.4 K and vary by less than 10 K, which is due to the daily natural variation. The all-solid-state system, which is compact, can be containerized and deployed at remote locations.     

压缩机试验台冷凝温度与过冷度的控制方法优化

为了提高压缩机试验台的控制精度与调节速度,用风冷式压缩冷凝机组和可调电加热器,将水箱中的冷却水温控制在一定的温度,再从水箱中引出2支水路,一路通到冷凝器,另外一路通到过冷器,并在这2支水路上分别设置自动调节阀,最终通过调节水流量大小,实现对冷凝温度和过冷度的精确控制。此方法可使冷凝温度、过冷度控制偏差均在0.02℃以内,工况稳定时间在30 min以内。     

Modeling for temperature compensation and temperature characterizations of BAW resonators at GHz frequencies

This paper deals with the temperature dependence of electrical and physical features of various kinds of solidly mounted resonators (SMR). The presented bulk acoustic wave (BAW) devices are designed for the 2 GHz application. The temperature coefficient of frequency (TCF) is determined from measurements well above the temperature range defined for wireless telecommunication system specifications. Therefore, evolution of electromechanical coupling factors and quality factors at resonance and antiresonance are also monitored. Results of characterizations show the trend for a subsequent theoretical temperature compensation study by using analytical modeling. To improve accuracy of modeling, an attempt to extract temperature dependence of dielectric permittivity epsilon(33) and piezoelectric coefficient e(33) is made. Finally, a well-known analytical model is modified to take into account the temperature dependence of length, density, stiffness coefficient, dielectric permittivity, and piezoelectric coefficient. Modeling highlights the need to deposit a material with positive temperature coefficient of stiffness on the top electrode. Realistic thickness of such a layer is determined. At the same time, it is necessary to adjust piezoelectric and electrode thin film thicknesses for simultaneously keeping a constant antiresonance frequency, reaching a zero temperature coefficient of frequency for antiresonance, and minimizing the decrease in the coupling factor because of the mass-loading deposition.     

电子产品高温试验箱的温度场分析及优化

环境应力筛选是电子产品生产过程中非常重要的环节,能激发并排除早期故障,而高温测试箱在此环节起着至关重要的作用,其性能好坏直接影响电子产品可靠性。现有的高温试验箱内部温度梯度较大,无法满足试验箱温度均匀的条件,会导致测试结果不准确,此外,加热时间较长,严重影响试验工作效率。结合西门子公司要求,文章以改善高温试验箱温度场分布、缩短加热时间为主要研究目标,首先利用流体仿真软件Fluent对现有高温试验箱进行温度场分析,再通过试验验证仿真的可靠性,并基于最后建立的仿真模型进一步提出环境试验箱的优化方案。结果表明,通过优化,将高温试验箱温度偏差从±4℃优化至±2℃,有效提高高温试验箱温度均一性,加热时间从70 min减少至25 min,加热速率提升一倍,为电子产品高温试验提供更完善的的试验环境。     

High temperature compression testing and determination of warm working temperature for commercial purity aluminium

CP aluminium was subjected to axysymmetric compression testing at 303, 373, 473, 573 and 673 K. Strength coefficient and strain hardening exponent were determined from log-log plot of true stress and true strain at different temperatures. True stress vs temperature at different strains indicated that dynamic strain ageing (DSA) occurred between 473 and 673 K. Warm working is to be done between 423 K and 473 K, so that optimum substructure hardening and strain hardening can be achieved during mechanical processing.     

温度综合自动检定校测系统

本文主要介绍温度自动检定校准系统的基本组成，功能和基本原理特点。提出的综合自动检定系统的特点是二等标准水银温度计与工业用热电偶热电阻温度计的检定装置合二为一，一套测量系统可面对多个恒温场输送过来的信号进行测试，体现信息时代特征的高科技产品开发方向。一机多用和计管合一是自动检定系统的核心思路。