用神经网络提高SO2传感器的检测速度

制作了新型IDC结构聚苯胺膜SO2传感器,测得不同SO2浓度的电导响应与恢复时间曲线。从这些气敏特性曲线出发,以电导响应曲线的斜率作为网络的输入,对应的SO2浓度作为输出,建立了BP网络预测推理模式,对四组数据的预测结果表明精度较高（误差小于3％）,具有很好的预测能力。这种方法不同于传统的标定方法,后者需要4min才能稳定的响应,神经网络样本检测不需要达到稳定的响应就可以预测SO2的浓度,从而大大缩短了结果的响应时间（缩短了75％）。     

基于互信息PSO-LSSVM的SO2浓度预测

针对火电厂SO2污染物排放问题,提出了一种基于互信息的粒子群寻优(PSO)最小二乘支持向量机(LSSVM)模型预测方法,通过筛选出与SO2实测入口浓度相关性较高的辅助变量,将其作为模型的输入,实现对主导变量SO2浓度的预测。利用互信息筛选出的辅助变量相比于机理分析、皮尔逊相关性筛选出的辅助变量具有更高的相关性。利用互信息筛选出的辅助变量作为LSSVM模型的输入以及粒子群法确定LSSVM的参数,不仅缩短了计算时间,还提高了预测精度。将该方法应用到某火电厂的SO2浓度软测量中,利用现场数据进行仿真,结果表明预测精度较高,相对误差较低,预测趋势更贴近实际值,减小了实际值与预测值的误差(均方根误差为2.485,平均相对误差为0.2603%),为现场的SO2浓度提前控制提供了软件技术支持。     

一种高频宽带换能器的设计方法

本文着重介绍一种高频宽带发射换能器的设计方法,并给出了它的电导响应曲线。     

侧壁四电极电容耦合非接触电导检测器(英文)

研制了一种集成于硅基电泳芯片分离沟道末端侧壁的新型四电极电容耦合非接触电导检测器.研究了该电导检测器的等效模型,对等效电路模型中的参数进行了公式推导,并讨论了影响电导检测响应灵敏度的相关因素.采用深刻蚀及离子注入加工技术制得了用于电导检测的立体电极.制作了基于锁相放大原理的信号处理电路,对该电导检测的频率响应及灵敏度进行了测试分析.实验结果表明,当激励信号频率为300 kHz时,该电导检测器具有最佳线性度;不同浓度Na+溶液响应电压差值为5 mV;检测限达到10-8mol/L;且成功实现了Na+和Li+混合无机阳离子的电泳分离在线检测.     

NASICON固体电解质SO2传感器的特性研究

采用溶胶-凝胶法合成NASICON固体电解质材料,并以其为基体材料制作管式SO2传感器,敏感电极采用Na2SO3-30?SO4或者Na2SO4-30?SO4(摩尔比)复合硫酸盐.SO2浓度在(10～100)×10-6体积分数范围内,两种器件的灵敏度分别为81.1和60.6mV/decade.敏感电极为Na2SO3-30?SO4的元件响应和恢复时间分别为28.2 s和57.7 s;敏感电极为Na2SO4-30?SO4的元件响应和恢复时间分别为39.8 s和67.4 s.     

许昌酸雨现状及原因分析

许昌有两大排放SO2的企业，年排放量3648吨。许昌空气中SO2、Ca2、Mg^＋的浓度变化具有较高的同步性。10月到次年2月值较高，此阶段空气污染最严重；其它月份空气污染物居中。许昌的酸雨危害比较严重，115个降水样本中，酸雨（PH〈560）的比例达到80％。要加强许昌城市排放综合管理,提高能源效率，多使用风能和太阳能等清洁能源。     

聚苯胺水基乳胶微粒的制备与性能研究

采用水溶性高聚物聚乙烯吡咯烷酮(PVP)作为空间稳定剂,利用分散聚合的原理成功地制备出了稳定的聚苯胺水基胶体分散液,聚苯胺复合乳胶粒子尺寸为几十至几百纳米,其粒径大小受PVP浓度、苯胺含量和反应温度等因素的影响.空间稳定剂可以提供胶体成核点.当PVP浓度较低时,聚合反应速率较小,当PVP浓度达到2%(质量分数)以后,聚合反应开始加速.红外光谱结果表明PAn-PVP复合物形成了分子内氢键.随着苯胺浓度的增加,聚苯胺电导率先增大后减少,最大值达到8.74×10-3S/cm,具有较好的应用前景.     

活化对不锈钢着色的影响

活化对不锈钢着色膜的均匀性和耐磨性有重要的影响.为此,研究了6种不同活化方法即HCI室温活化、H2SO4室温活化、H2SO4阳极活化、H2SO4阴极活化、H2SO4高温活化、H2SO4-CrO3阳极活化对不锈钢着色的影响,测定了不锈钢着色的电位-时间曲线,讨论了电位-时间曲线的参数tB与tC的对应关系及其对不锈钢着色质量的影响.结果表明:活化可加快着色过程,有助于获得光亮、均匀、耐磨的着色表面;升高温度有利于活化;阳极电解活化明显优于阴极电解活化;相同浓度的HCI和H2SO4溶液的活化效果相当;10%的H2SO4阳极电解活化的效果最好;可以用tB或tC的大小来表征活化效果及着色的难易程度.     

聚合型咪唑啉缓蚀剂的合成与性能

为提高咪唑啉缓蚀剂的水溶性及缓蚀效率,以己二酸与二乙烯三胺为原料合成了带酰胺和咪唑啉基团的聚合型缓蚀剂PIM,以羟乙基乙二胺为原料合成了常见的非聚合型缓蚀剂UPIM;采用红外光谱和质谱测试了2种缓蚀剂的结构及分子量;采用交流阻抗法分析了2种缓蚀剂在N80钢表面的吸附性质,并拟合了表面覆盖率和时间的关系曲线;采用Tafel极化曲线法测试了不同浓度缓蚀剂对N80钢的缓蚀性能.结果表明:N80钢在含50mg/LHM的0.5 mol/L H2SO4溶液中浸泡6 min后,覆盖率达到85.02％,高于UPIM;当0.5 mol/L H2SO4溶液中聚合型缓蚀剂PIM浓度为400 mg/L时,缓蚀率最高可达96.7％,明显高于缓蚀剂UPIM的;经过较长时间腐蚀后,聚合型缓蚀剂PIM在金属表面的吸附稳定性优于UPIM的.     

镍-钴／镍／镍-钴镀层的制备及电化学性能

采用直流和脉冲方法电沉积了镍-钴／镍／镍-钴多层镀层。通过SEM对镍-钴／钞镍-钴镀层的微观结构进行了表征,采用Tafel曲线外推法、交流阻抗法、阳极极化曲线法等方法对镍-钴／镍／镍-钴镀层在0．1mol／LH2SO4和1％NaCl混合溶液及10％NaOH溶液中的耐腐蚀性能进行了表征。结果显示：镍-钴／镍／镍-钴镀层的表面致密均一;在0．1mol／LH2SO4＋1％NaCl溶液中的腐蚀电位最正,传质电阻最大达到i642Q·cm2;在10％NaOH中钝化区为542mV,具有较好的钝化效果。     

Estimation of Parameters of Universal Distribution of Moments of Failure of Products

A method is proposed for estimating the parameters of a mixture of exponential and Weibull distributions for which the accuracy of preliminary estimates obtained by graphical analysis is refined in accordance with the criterion of maximum likelihood. The efficiency of the proposed method is supported by the results of statistical modeling.     

Evaluation of optical properties of highly scattering media by moments of distributions of times of flight of photons

A novel method for the determination of the optical properties of tissue from time-domain measurements is presented. The data analysis is based on the evaluation of the first moment and the second centralized moment, i.e., the mean time of flight and the variance of the measured distribution of times of flight (DTOF) of photons injected by short (picosecond) laser pulses. Analytical expressions are derived for calculation of absorption and of reduced scattering coefficients from these moments by application of diffusion theory for infinite and semi-infinite homogeneous media. The proposed method was tested on experimental data obtained with phantoms, and results for absorption and reduced scattering coefficients obtained by the proposed method are compared with those obtained by fitting of the same data with analytical solutions of the diffusion equation. Furthermore, the accuracy of the moment analysis was investigated for a range of integration limits of the DTOF. The moment analysis may serve as a comparatively fast method for evaluating optical properties with sufficient accuracy and can be used, e.g., for on-line monitoring of optical properties of biological tissue.     

Estimation of potentialities of methods of summation of direct measurement errors

Conventional methods for summation of direct measurement errors are considered. Conditions under which these methods provide consistent results are stated. It is proposed to utilize for characteristic of the total error, its interval estimator or the half-sum of the value obtained by adding up its arithmetic and geometric random errors.Translated from Izmeritel'naya Tekhnika, No. 4, pp. 10–12, April, 1995.     

空压机轴承箱蜗壳温度探头油封改造

由于空压机进气侧轴承箱蜗壳温度探头密封效果不好,使空压机及其后续管道受到油污染。后将温度探头的O形圈密封改为骨架油封,杜绝了轴承箱漏油问题。文章简介空压机的结构和技术参数,详细介绍了骨架油封的制作和优点。     

Characteristics of mechanical properties of materials in studies of conditions of attainment of marginal states

It is shown that conditions of attainment of marginal states in the material of structural components are formulated on the basis of analysis of force and deformation criteria of formation and development of destruction. The parameters of these criteria are data on types of structural materials, standard and special characteristics of their mechanical properties, structural forms of considered elements of the equipment, and their operating stress loading. In this case, the construction of a system of state equations for describing interrelation of current damage, external actions, and responses to them is based on the concept of calculating variations in properties of materials at all stages of the design life cycle.     

Determination of parameters of microstructural inhomogeneity of deformation of metals by the method of modeling

The article suggests a method of evaluating the microstructural inhomogeneity of deformation of metals by modeling. The method includes the measurement of deformations of metal according to meshes of a dividing grid with small base and the calculation of the distribution parameters of microdeformations in model representation. It is shown that the modeling method makes it possible objectively to evaluate the microinhomogeneity of deformation of metals independently of the chosen mesh size of the dividing grid. New structural characteristics are introduced: the base and wave of variation expressing the degree of crumbling or amalgamation of metal grains by inhomogeneity of deformation.Translated from Problemy Prochnosti, No. 7, pp. 40–44, July, 1991.     

Analysis of the rate of propagation of the wave of change of boiling modes

An approximate analytical expression is derived for the velocity of the front of the wave of change of boiling modes on a rod and on a plate. The impact of the Thomson effect and of the heater orientation in the gravity field is included. Adequate agreement is demonstrated between the derived relations and experimental data.     

水三相点复现的不确定度评定

水三相点是开尔文热力学温度的唯一基准点，也是ITS-90国际温标重要的定义固定点。因此，水三相点不确定度分析对整个温标的建立、温度量值传递起着至关重要的作用。近3年来，中国计量科学研究院研制出一系列高质量的水三相点容器，加强了水三相点的研究，为不确定度的分析提供了更为可靠的实验依据。同时，不确定度的分析也是客观评价新研制容器性能的一个重要指标。因此，根据实验结果对新研制容器所复现的水三相点进行了不确定度评定。评定结果表明，其扩展不确定度为0．16mK(k=2．69，P=0．99)。