适用于硫铁矿焙烧的微机化氧分析仪研究

介绍一种新型微机化氧量自动分析仪,该仪表改进了铂电极的涂敷工艺;减小了氧化锆探头组件和发热件的几何尺寸,并改进其形状;转换器采用MCS—51系列单片机8031芯片,仪表具有自诊断功能。仪器的主要技术指标:测量精度5级,非线性误差≤0.05％O_2,加热器温度波动《±2℃,测量范围0～5％(线性)或0～10％(对数)。     

GMR电涡流探头的零电势自动补偿技术研究

研究了以单片机为核心的GMR电涡流探头零电势自动补偿新方法.首先采用锁相放大技术获得零电势的幅值及其与基准信号的相位差;接着应用单片机控制数控移相器和数控幅值调节器改变基准信号的相位和幅值,获得与零电势一致的补偿信号;最后应用该补偿信号与零电势相减,使得此时的输出接近于零,实现了零电势的自动补偿功能.以铝板试件进行了检测实验验证.应用该技术进行零电势自动补偿之后,电涡流探头零电势的输出值约为补偿前的4.05%,补偿精度达到了检测实验系统的要求.表明该技术很好地实现了探头零电势的自动补偿,显著地提高电涡流检测系统的灵敏度,同时也增强了电涡流检测系统对深层缺陷的检测能力.     

CFRP蒙皮-CFRP胶接质量的原位超声检测技术

根据CFRP蒙皮-CFRP胶接结构的特点,采用窄脉冲超声反射法对其胶接质量进行原位检测;仿真分析了胶接结构中胶膜及界面脱粘对超声波反射信号的影响;并用自制的窄脉冲延迟块超声探头对脱粘试块进行检测。仿真分析表明:窄脉冲超声波反射信号能够检测Ⅰ界面脱粘;d/λ(胶膜厚度/超声波波长)≤0.5时,能够检测Ⅱ界面脱粘。实验结果表明:自制的5 MHz探头产生的脉冲周期不大于1.5周,达到窄脉冲的要求;采用超声反射法检测时自制的5 MHz探头能够检测出Ⅰ界面脱粘和厚度不大于0.5 mm胶膜的Ⅱ界面脱粘,满足实际产品的原位检测需求。     

基于脉冲宽度调制技术的超声波测风系统研究

给出了时差法超声波测风系统的总体设计,分析了几种改善超声波信号到达时刻的方法。重点提出了一种基于脉冲宽度调制技术(PWM)的超声波驱动信号的具体实现方法。同时对采用和不采用调制技术两种方案进行了详细的对比分析,结果表明采用调制技术的驱动脉冲更有利于正确判决超声波回波信号的到达时刻。所设计的超声波脉冲驱动方案对基于时差法的超声波风速仪具有重要的参考价值。     

流程工业仪表故障快速检测方法

通过对大量真实工业数据的统计分析,发现仪表测量信号变化量的方差能很好地表征仪表性能的稳定状态,由此提出了一种基于信号方差分析的快速仪表故障检测算法,并在此基础上开发了一套在线仪表故障检测系统.该系统以诊断数据库为核心,包括实时数据采集、仪表故障在线诊断、故障数据的保存与查询、诊断参数自学习以及远程访问功能.工业应用结果表明,这种故障检测方法能够对仪表早期的故障作出正确的判断.且检测迅速,物理意义明确,适用于大规模的流程工业过程.     

基于单片机的步进电机控制系统设计

采用单片机AT89C51对步进电机进行控制,通过I/O口输出的具有时序的方波作为步进电机的控制信号,用5个按钮来对电机的状态进行控制,利用MAX232接入计算机串行通信接口芯片将软件设计程序输入到单片机里,单片机根据电机的状态信号将写入的程序通过CPU进行处理,发出脉冲控制信号,脉冲控制信号经过芯片ULN2003A驱动步进电机,步进电机将脉冲控制信号转换为电机的角位移,使电机的转子根据脉冲数来实现电机准确的转速控制。采用74LS164作为6位单个数码管的显示驱动,CPU根据发送过来的指令进行相应的动作,从而使数码管能够显示出相应的转速,同时步进电机也根据脉冲信号的频率和脉冲数开始旋转。通过实际调试,步进电机能够实现正转、反转、加速、减速等功能。     

基于PLC的稠油开采防堵预警系统

针对稠油开采过程中易出现的井堵问题,结合空心杆掺水稠油开采工艺,将实时注水流量作为井堵判断依据,基于PLC和单片机开发出经济型防堵预警系统.根据所选流量计脉冲输出信号宽度为4ms而周期较长的特点设计展宽电路,利用普通I/O口实现高速脉冲计数功能;PLC根据实测瞬时流量与设定流量下限阈值的比较,自动判断井况;基于单片机利...     

复合材料框架胶接接头超声检测研究

针对碳纤维复合材料框架胶接接头的胶接质量问题,提出了使用0.5～10 MHz的宽带窄脉冲探头单侧进行脉冲回波法快速检测。采取试验与理论相结合的方法,采集11种常用接头结构超声波,对其传播特性和检测信号特性进行分析。研究结果表明:试验提出的方法实现了对复合材料框架胶接接头的胶接质量检测,对实际工程检测具有较强的指导意义。     

基于AT89S52单片机的超声波测距仪

本文介绍了一种基于DS18820的AT89S52单片机超声波测距系统，阐述了DS18820测温原理．由温度可算出实际环境下的超声波速度，利用AT98S52的计数器可以获得超声波在两探头之间的飞行时间，已知超声波的传播速度和飞行时间可以获得两探头之间的距离。整个系统结构简单、工作可靠，有良好的测量精度。     

涡待流量计的使用与维护

在甲醇生产过程中,要使用很多流量计,如主塔入料、预塔入料、主塔回流、预塔回流、软水加入及精甲醇采用等过程。这些流量计的正确使用,不仅对提高产品的产量和质量有很大的帮助,而且对稳定生产和安全操作也有着极其重要的意义。我厂在甲醇生产过程中共使用了6套YF102－ALPC2型涡街流量计传感器以及配套的XSJ－391型流量积算仪,涡街流量传感器接受二次仪表的24VDC供电,采用压电晶体元件检测旋涡分频,安装在探头体内的压电晶体元件感受到一变力作用产生交变电荷,经过传感器处理输出一定幅度的脉冲信号给二次表,这一脉冲信号与流过管道的流量成正比,这一比例关系由传感器的K系数决定。二次仪表是由MCS51系列单片机8031为主体的流量显示仪表,其在接受这一脉冲信号之后,一方面由指示电流表显示瞬时流量,一方面显示累计流量。     

Reversed-Phase high-performance liquid chromatographic analysis of triacylglycerol autoxidation products with ultraviolet and evaporative light-scattering detectors

The oxidation products of triacylgycerol standards (trilinolenin, trilinolein and triolein) and a natural mixture of rapeseed oil triacylglycerols were analyzed with a reversed-phase high-performance liquid chromatographic method. The oxidation products were detected with ultraviolet (UV) and evaporative light-scattering detectors (ELSD). The chromatographic profiles obtained with these two detectors were similar for all samples except triolein. ELSD is a mass detector and can detect the oxidation products of triolein and other compounds that do not have conjugated dienes in their structure. The two detectors can be used in series. The sensitivity of ELSD approached that of the UV detector used. ELSD seems to be a good universal detector type for monitoring autoxidation products of edible oils.     

Quantitative Analysis of PAH in Pitch by HPLC with Fluorescence Detector

Abstract

This communication evaluates alternate sample preparation, PAH extraction and different high performance liquid chromatography (HPLC) analytic techniques for the analysis of PAH in pitch. The HPLC response using fluorescence (Fl) and particle beam mass spectrometric detectors are compared. An analytical methodology is proposed which assures a repeatability better than 7% for the 14 PAH examined. The pitch sample is meticulously ground and the polycyclic aromatic hydrocarbons are solubilized with ultrasonic agitation in acetonitrile. The filtered extract is diluted and finally eluted in an analytical column with a fluorescence detector and optimized wavelength selection. Results will be presented comparing PAH levels for selected pitches supplied to the aluminium industry.     

采用带示差折光检测器的高效液相色谱法检测肌醇

通过实验得到了一种简单、快速、准确分析肌醇的方法。该方法采用带示差折光检测器的高效液相色谱仪,Spherisorb C18色谱柱,色谱流动相为蒸馏水,经超声脱气后,流动相流速为0．8 mL/ min,进样量为20μL。实验证实,采用带示差折光检测器的高效液相色谱法所测得的肌醇样品质量分数重现性好、标准偏差小。     

二极管阵列检测器在农药液相色谱分析中的应用

二极管阵列检测器是一种基于光电二极管阵列技术的新型检测器.使用二极管阵列检测器,可以对色谱峰进行光谱扫描、峰纯度鉴定等定性分析,在方法研究中可以快速选择最佳检测波长,在多组分混合物分析中可以编辑波长程序.由于具有这些明显优势,二极管阵列检测器在农药分析中有着极佳的应用前景.     

Diamond photodetector response to deep UV excimer laser excitation

Diamond photoconductive detectors have previously been shown to be suitable for detection of deep ultraviolet nanosecond-scale pulses from excimer lasers, which are to be used in next generation lithographic systems. Using simple test circuitry and low bias voltages easily measurable responses were observed when these detectors were illuminated with laser pulses at typical laser fluence levels. However, as the laser fluence is increased the detector response appears to broaden and change shape as well as increase in magnitude. In this paper we present analysis of the response of these detectors. This analysis shows that over the laser fluence range used the magnitude of the detector response exhibited a linear response. By approximating the temporal evolution of the laser pulse and simulating the transfer characteristics of the test circuit it can be seen that the pulse broadening and shape change seen with increasing fluence can be explained by the test circuit. The shape of the detector response, therefore, closely resembles the temporal shape of the laser pulse, demonstrating that these devices are fast enough to give a true representation of 10–15 ns laser pulses at a wavelength of 193 nm.     

基于I2C总线的气相色谱控制平台的设计

利用I2C总线的一主多从、接口线少及实现简单等特性,结合PIC16F877单片机,采用多种功能模块组合编程,实现了一种简单、灵活的控制系统.     

可燃性气体探测器针对汽油油气探测规律的研究

主要是气体探测器针对可燃性气体组分的研究,在探究过程中利用不同类型气体标定的气体探测器对可燃性气体进行测定,分析可燃性气体中的重要组分,分析两者气体探测器示数和可燃气体含量之间的关系,同时探究不同类型探测器在同一气体环境下测定数据结果之间的关系,通过对数据的分析,使可燃气体探测器更好地应用于实际生产中。     

Ultrasonic characterization of the crystallization behavior of poly(ethylene terephthalate)

On the basis of the previous observations that the ultrasonic signals are sensitive to the crystallization of polymers (Tatibouet and Piché, Polymer 1991, 32, 3147), we have expanded our efforts to study the detail relationship between the ultrasonic signals and crystallization process in this work. The nonisothermal and isothermal crystallization of virgin poly(ethylene terephthalate) (PET) and PET samples after degradation were studied by using a specially designed pressure‐volume‐temperature (PVT) device, with which an ultrasonic detector was combined. The results showed that the evolution of the ultrasonic signals not only can be used to probe the crystallization process but also can qualitatively characterize the crystallization rate, crystallinity, crystallite size, and amorphous. DSC measurement was used to verify such results. Ultrasonic signals could be as a complementary tool to polymer chain movement and well be applied to characterize the crystallization behavior. Furthermore, the ultrasonic measurement has the potential use to characterize crystallization of products in‐line during processing (i.e., injection molding, micromoulding). © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Optimal placement of gas detectors: A P‐median formulation considering dynamic nonuniform unavailabilities

A stochastic programming formulation (SPqt), based on the P‐median problem, is proposed for determining the optimal placement of detectors in mitigation systems while considering nonuniform dynamic detector unavailabilities. Unlike previously proposed formulations, SPqt explicitly considers backup detection levels. This allows the modeller to determine the maximum degree of the nonlinear products to be used based on the trade‐off between computational complexity and solution accuracy. We analyze this trade‐off on formulation SPqt results by using 4 real data sets for the gas detector placement problem while using unavailability values obtained from real industry gas detector data. For this data, our results show that two detection levels are sufficient to find objective values within 1% of the optimal solution. Using two detection levels reduces the nonlinear formulation to a quadratic formulation. Three solution strategies are proposed for this quadratic formulation and then compared from the computational efficiency perspective. © 2016 American Institute of Chemical Engineers AIChE J, 62: 2728–2739, 2016     

质谱法检测甜菜碱含量室内实验研究

应用Waters质谱检测器,建立一种应用反相超高液相色谱-质谱检测器直接检测玉门油田采出液中磺基甜菜碱的分析方法。本方法采用Waters BEH C18色谱柱1.7μm(2.1×50 mm),以A:水,B:甲醇+0.5%甲酸为流动相进行梯度洗脱,流速为0.3 m L/min,柱温25℃,毛细管电压1.5 k V,锥孔电压30 V,扫描方式SIR 436正离子扫描,对玉门油田所用的R型磺基甜菜碱进行实验室内模拟分离检测。当R型磺基甜菜碱质量浓度在0~60 mg/L范围内,其峰面积与进样量成较好的线性关系,重复率高,大于97%,应用玉门油田现场采出液的加标回收率在95%~102%之间,相对误差小于5%。结果表明,该方法操作方便,结果准确,可以指导玉门油田现场实际生产工作。