基于SCR催化的步进电机系统设计

我国大气污染状况十分严重,氮氧化物是形成酸雨、雾霾、光化学烟雾的重要成因之一,其中以汽车尾气污染最为严重,为减少尾气污染的持续恶化,提出一种基于SCR催化的步进电机系统。该系统是一个涵盖了步进电机,热电偶,LED屏幕以及SCR催化的多领域复合系统。利用热电偶温度传感器采集温度信号控制步进电机的转动,电机固定连接的转子外围三个大小深度相同的小孔在转动下导出尿素,尿素经SCR反应加热腔催化生成对大气无害的N2和H2O。     

温度测试系统中的误差分析与控制方法

温度测试系统是飞行器飞行试验中关于系统发射环境温度参数等的测试装置之一。本文从热电偶传感器结构设计与材料选择、信号放大与采集及数据处理等几方面出发,分析了某飞行器飞行试验温度测试系统存在的误差因素;结合飞行试验情况,并按照实际应用的标准,给出了有效提高系统测试精确度的相应控制措施。最后通过试验情况的相关对比,验证了文中所述误差控制方法的有效性。     

基于低温冷冻治疗仪的温度测量方法

采用热电偶信号放大器AD595结合K型热电偶温度传感器,设计基于低温冷冻治疗仪的热电偶测温电路;实现了冷端自动补偿、温度曲线升降功能;测量电路结构简单、成本较低,具有较强的实用性。     

一套简单实用的热电偶实验装置

本文介绍一种为学生开设热电偶实验的装置，该装置简单、实用、成本低廉，能较好地达到实验目的。     

借助显微镜用普通偶丝制作微细热电偶

尝试在显微监视条件下通过电解腐蚀方法,用直径100 μm的普通热电偶丝制作尖端直径小至10-20 μm的微细偶丝,经电火花焊接形成微细热电偶。热偶接点的热容量可较普通情况减小约三个数量级。由本方法制成的微细丝段的长度大于1 mm,长径比大于30,因此未经腐蚀的粗偶丝部分不会影响接点的测温响应特性。本文介绍了微细尖端热电偶的制作方法,并指出进一步改进的方向。     

神经网络在标准热电偶测温中的应用

热电偶在工业测温中有着广泛应用，但其温度和热电势之间呈非线性关系，实际应用中需要采用标准化热电偶并存储和查找分度表来得到实测温度，这样既限制了测温精度，又使其在热电特性发生变化后很难再用。本文利用人工神经网络自学习、自适应的特点以及多层前向神经网络的函数逼近能力来解决热电偶温度计算的问题，并给出了两层前向神经网络和BP算法计算热电偶温度的详细过程。结果表明，这种计算方法准确性高、实用性强。     

铂铑-铂温差电偶的精确测温及不确定度评定

介绍了利用电势差计对铂铑－铂温差电偶测温计精确标定的方法。通过对测量结果的不确定度评定，给出利用该方法所测温度的不确定度为0．5℃。     

Calibration coefficient of a heat-flow DSC. Part I. Relation to the Sensitivity of a thermocouple

Relation between the calibration coefficient of a DSC sensor k(T) and the sensitivity of a thermocouple e(T) which the sensor is made from was derived from the analysis of a heat transfer inside a DSC cell. Ratio e(T)/k(T) is equal to A+BT ³. The first component depends on heat conduction and the second one on radiation. The relationship was tested for DSC-204 Netzsch using (i) data on calibration vs. enthalpies of phase transitions (reference samples) and (ii) measurements of heat capacity of corundum. Both tests show very good agreement between experimental data and predicted theoretical function. This revised version was published online in July 2006 with corrections to the Cover Date.     

A Cmos Interface for Thermocouples with Reference-Junction Compensation

This paper presents a CMOS interface for a thermocouple, includingreference-junction compensation. The interface contains a first-orderoscillator whose period is modulated by the signal from the thermocouple(V_X) and two other signals generated internally. One is abase-emitter voltage (V_BE) and the other is a PTAT voltage(V_PTAT). Linear combinations of the periods corresponding tothese two voltages are made by a µC, to obtain a reference signal anda temperature-dependent signal. The internal signals are required to provideauto-calibration for offset and gain and to measure the interface internaltemperature. Dynamic Element Matching is applied to generate an accurate andreliable PTAT voltage. The inaccuracy in the base-emitter voltage iscalibrated using a vertical PNP substrate transistor with multi-emitterareas. The applied modulator used in the circuit has a second-orderfiltering which suppresses low-frequency (1/f) noise. This filteringproperty enables the use of a low-cost CMOS process for the implementationof the circuit. The interface is able to measure a voltage(V_X) in the range of –27 mV to 100 mV, the measuredaccuracy of the system over a temperature range of –25°C to75°C is 550 ppm of V_X ± 2µV. The inaccuracyin determining the reference-junction temperature is 0.6 K. The measuringtime is 50 ms.     

实用型计算机实验教学模型的研发

该系统以单片机为控制机，利用热电偶、液位传感器、加热器等作为数据采集和控制部件，构成工业控制现场模型。对蓄水槽中的水进行温度、液位的监控。本文论述了该教学模型的构成、工作原理及研发中的主要技术问题。