消除材料敏感性的电涡流传感器测量电路

被测材料的电磁特性会影响传感器的输出性能,限制其使用范围。为此,在分析阻抗投影变换原理的基础上,设计了一种能实现该原理的测量电路,用以消除传感器对被测材料的敏感性。11mm传感器输出测试实验的结果表明:所用7种被测材料经线性补偿后的输出特性曲线近似重合,可用一条直线替代,实现了消除材料敏感性的功能;计算出的传感器材料敏感性误差为±1.8%。     

半导体型氯气传感器变送电路的研究

半导体型氯气传感器是一种电阻式的传感器,有着非线性的输出。本文以Zn基半导体氯气传感器为探头,分析了其性能,通过运用对数电路、反对数电路设计了其变送电路,使其具有线性的输出,达到直读的目的。     

基于线性差动变压传感器的高精度微位移测量系统

针对现有微位移测量系统的不足,设计了一种高精度微位移测量方案。设计完善了信号调理电路,以线性差动变压传感器作为位移敏感元件,提出一种新的线性差动变压传感器正弦激励信号产生方法和多重反馈有源带通滤波器基波信号抽取电路。同时,为整个系统设计了完善的供电系统,采用TOP224构成反激式变换电路,再通过线性电源变换器转换至相应电压。微动测量架的校验结果表明,系统精度达到了1μm。     

测试室外轮胎噪声传感器的研制

介绍用于测试室外轮胎噪声的传感器的研制。该传感器由2个扬声器、阻抗匹配电路、功放电路和微机，或由2个驻极体话筒、功放电路、A／D转换电路和微机构成，其频谱响应曲线可用微机软件修正，使其平直。虽然该传感器的测试值为比较值，但其实用性强，性价比高，具有一定的推广价值。     

压力传感器静态标定试验数据的计算器和计算机处理

本文从数据采集的角度出发，首先通过构建线性压力传感器静态标定数据模型，设计具备科学性特点的柔性薄膜压力传感器阵列；其次探讨有关压力传感器静态标定试验数据计算机处理的相关内容，利用压力传感器实现对相关数据的精准采集，分析并行式采集电路与统筹式算法，明确多种压力数据的具体分布。最后以并行、单通道不同的电路形式为前提条件，测试压力传感器静态标定试验数据，结果显示柔性薄膜压力传感器的压力分布采集系统能够准确、快速地实现对压力传感器静态标定试验数据的有效采集与处理。     

基于LVDT微位移测量系统中AD698的应用

介绍了AD698在微位移测量系统中对信号调节的应用,并对线性差动式位移传感器(LVDT)的结构和工作原理进行了简单的介绍,给出了AD698在LVDT实际应用中的电路原理图,分析了电路中产生噪声的原因和对噪声的处理,达到了理想效果.     

一种温湿度测控系统的设计与模拟

基于单片机与数字传感器DHT11,设计了一种简易的温湿度测控系统。分析了DHT11的内部结构、时序和工作原理,提出了采用74L151实现8路切换式多点测量的方法,设计了数字传感器、键盘、LCD液晶显示器和数据选择器与单片机的接口电路。结合硬件给出了测量系统的程序流程。通过室内温湿度模拟实验,得出系统的线性度为1.5%;重复性:湿度为2%RH,温度为1℃;精度:湿度±2%RH,温度±1.5℃;分辨率:湿度1%RH,温度1℃。     

压电式涡路流量计

涡路流量计是一种新型流量测量仪表,它通过检铡流体力学中著名的卡门涡路频率来测量流体的流量,具有线性好、压损小、量程比大、结构简单、没有可动件、讯号数字化等优点。检测涡路频率的方法很多,其中已被广泛采用的一种方法是用热敏元件作传感器。但由于热敏元件需要配置恒流电路进行加热,电路相对来说较为复杂;封装工艺上既要保证元件与流体介质绝缘,又要满足热     

玻璃管液位计的实验研究

对玻璃管进行加工处理，使其成为一电容式液位传感器，经电容－周期转换电路将电容转换为矩表脉冲输出。通过测量脉冲周期得到液位的高度。实验表明数据的重复性和线性较好，引用误差小于０．３２％。     

应用“手持技术”测定酸与碳酸钠的反应速率

在密闭容器内进行碳酸钠与稀盐酸、稀硝酸和稀醋酸的反应,利用压强传感器记录随着二氧化碳的产生压强随时间变化的数据,通过软件自动绘制压强—时间变化曲线,进行线性拟合后根据曲线的斜率计算出化学反应速率。通过改变酸的浓度和种类探究不同浓度和不同种类的酸与碳酸钠的反应速率。     

COMPARISON OF METHODS OF ANALYSIS OF GYPSUM1

The different analytical methods proposed for the evaluation of gypsum have been subjected to an experimental test. A combination method, consisting of a fusion with KHCO₃ and determination of CaO by KMnO₄ titration, the SO₃ by Andrews method of titration of BaCrO₄ has been found to give very reliable results with the least consumption of time.     

氢气纯度分析方法准确性的探讨

ONACCURACYOFANALYSISOFOFHYDROGEN1前言我公司目前应用的氢气纯度分析方法有两种,一种是爆炸反应法,另一种是焦性没食子酸吸收法。几年来,人们对两种分析方法的准确性曾有过褒贬不一的评论。这里我们也谈谈自己粗浅的观点。2爆炸法测定氢气纯度一定量的氢气样品与适量的空气之均匀混合物因反应后生成液体水而引起气体体积减少,减少的体积等于参加反应气体体积之和。其中l／3为氧气,2／3为氢气。根据氢气取样量和反应前后混气体体积之差,以及氢气在反应中的体积比例关系,可计算出样品的氢气纯度。计算公式式中：A一混…     

HEASUREHENT OF INSTANTANEOUS RATES OF LOSS OF VOIATILE COMPOUNDS DURING DRYING OF DROPS

A novel technique serves to monitor instantaneous rates of loss of a volatile solute from a suspended drop during drying. A highly sensitive electron capture detector is used to monitor concentrations of SF6 released into a flowing gas stream from a suspended, drying drop. Simultaneously, the appearance and morphological development of the drop are monitored with a video camera. This provides the wherewithal of relating instantaneous rates of loss of the volatile solute to particular events during the development of particle morphology.

Initial experiments have been carried out with drops of aqueous solutions of glucose, sucrose, maltodextrin and coffee extract. The results clearly display the onset of the volatiles-retentive selective diffusion phenomenon. There is also substantial loss of the volatile component later in the drying process, when the drops undergo repeated ex ansion, bursting and cratering due to the formation of internaf bubbles. These experiments appear to be the first quantitative demonstration of major losses accompanying changes in drop morphology.     

ANALYSIS OF RECENT MEASUREMENTS OF THE VISCOSITY OF GLASSES

Viscosity of Simple Soda-Silicate 500° to 1400°C Comparison of the results given by English with those of Washburn, Shelton and Libman, indicates a discrepancy in the absolute values of log₁₀ viscosity amounting to 0.6, those of Washburn et al., being relatively too high. If correction for this is made, the isothermal curves of log₁₀ viscosity as a function of soda content are smooth up to 50% Na₂O, showing no inflection. The observations as a function of temperature T are all represented within accidental error by an equation of the type where all three constants vary regularly with the composition. Change of Viscosity of Glass (6SiO₂, 2Na₂O) due to Molecular Substitution of CaO, MgO and Al₂O₃ for Na₂O The effect is clearly brought out by plotting (from the results of English) the change of log₁₀η due to the substitution as a function of temperature. The curves each show a sharp bend at a temperature between 840° and 1050°C, which is designated the aggregation temperature T_a. If we divide these curves by the corresponding percentage substituted, we get curves for each oxide which are straight and parallel below the aggregation temperatures, the slopes (increase of change of log₁₀η per 100°C) being −0.056 (CaO), −0.055 (MgO), −0.018 (A1₂O₃) per per cent oxide substituted. For substitution of 1/2 molecule the slopes are −0.325 (CaO), −0.23 (MgO) and −0.18 (Al₂O₃) per 100°. At the aggregation temperature the change of log₁₀η per per cent is a minimum, 0.03 to 0.06 for CaO, 0.12 for MgO, 0.07 for Al₂O₃. Evidence of Aggregation in Glasses, from viscosity Measurements The sharp bends in the plots of change of log₁₀η due to substitution of an oxide for Na₂O, suggest the beginning of molecular aggregation at these temperatures. These aggregation temperatures are close to the devitrification temperatures, but the effect on the viscosity curves cannot be due to actual devitrification since it does not change with time. Taking the aggregation temperatures as equal to devitrification temperatures, additional isotherms are roughly sketched into the equilibrium triangle of the system Na₂O-CaO-SiO₂. Change of Viscosity of Glass (4SiO₂, 2Na₂O) due to of Substitution of B₂O₃ for SiO₂ The change of log₁₀η (from the results of English) is plotted as a function of temperature, and also the change of log₁₀η per per cent B₂O₃. The curves are more complex than for the substitution for Na₂O.     

环氧树脂羟基值测定方法的研究

利用乙酸酐、吡啶和浓硫酸混合的乙酰化试剂测定环氧树脂中羟基值含量的方法具有操作简便、滴定终点明显和分析结果误差小等优点。     

骑式摩托车油箱喷涂工艺的改进

面对日益激烈的市场竞争,摩托车油箱外观质量越来越成为影响销售的因素之一。文章介绍了改进工艺后的油箱涂装,该涂装体系提高了油箱外观的丰满度,降低了油箱涂装的生产成本。     

茶多酚提取方法进展

本文综述了国内外现有茶多酚提取方法的现状以及近期的研究进展，并对其优缺点进行了评价。这将有助于中低档茶的综合利用和茶多酚的进一步开发应用。     

SEDIMENTATION OF BINARY MIXTURES OF PARTICLES OF UNEQUAL DENSITIES AND OF DIFFERENT SIZES

A model is developed for the sedimentation from a suspension of two particle species of unequal densities and of different sizes. The composition and the thickness of various layers in the sediments are predicted using graphical and analytical methods. The model predictions were in excellent agreement with experimental results, when the particle size ratio was ≥ 108. When size ratio of the particles was 2.60 and 4.31 the agreement occurred in about 50 percent of the cases.     

用两个形状指数表征粉煤灰颗粒形貌的研究

引用两个形状指数表征颗粒形状的概念,即先将颗粒形状近似为椭圆,再将椭圆图像分离:以圆为基准的颗粒宏观形状指数δ;以光滑椭圆为基准的颗粒轮廓凹凸度,即微观形状指数ζ。分析和发展了近似椭圆模型。并运用图像分析仪对粉煤灰、水泥样品进行实验。结果表明,粉煤灰颗粒的两个形状指数δ和ζ都大于水泥颗粒。证明粉煤灰颗粒的球形度、表面光滑度优于水泥,而且,随着粒径增大,δ和ζ呈下降趋势,表明磨制颗粒越粗。(?)粒形状越不规则。文中还运用近似椭圆模型再现了颗粒的模拟图像。     

典型煤碳燃烧特性研究和数值模拟

本文以三种典型煤的碳燃烧为研究对象，分别采用简单一维沉降燃烧方式和等温加热燃烧方式，实验研究了煤在快速加热条件下，其碳的初期和中，后期燃烧过程。以实验为基础，建立了煤的碳燃烧模型，变工况数值模拟了煤的碳燃烧过程，揭示了煤不同条件下的单颗粒碳燃烧特性。