原子荧光光谱法测定植物样品中痕量镉的含量

建立微波消解-原子荧光光谱法测定植物样品中的镉含量的方法。用微波消解仪器对植物样品进行消解,在最佳仪器反应条件下,测定植物样品中镉的含量。镉浓度为0.1~0.8 ng/mL时荧光强度与镉浓度呈显著的线性关系,r=0.9995,方法的检出限为0.0018 ng/mL。向植物样品中分别添加一定浓度的镉,3个样品的回收率在90.4%~92.1%之间。方法的精密度为1.64%。该方法简便、快速,有较高的灵敏度、准确度、精密度和较低的检出限,适合植物样品中镉含量的测定。     

近红外光谱法测定三元混合物中氯苯的含量

利用近红外光谱分析结合偏最小二乘法测定甲苯、氯苯和正庚烷构成的三元混合体系中氯苯的浓度。通过考察混合物吸光度与氯苯浓度的相关性,以预测残差平方和为评价指标,对光谱进行了变量筛选,并将选择的33个波长变量建立的定量校正模型与全谱范围的校正模型进行比较。结果表明本方法可使最终所得的模型中变量数大大减少,通过波长变量优选最小化冗余信息、提高预测精度及建模效率。     

汽油样品预处理方法的探讨：汽油中痕量铅的测定

本文研究测定汽油中痕量铅时两种预处理测定方法：（１）碘－正辛醇萃取－硝酸反萃取－离子交换、洗脱后用阳极溶出法测定;（２）微波提取－原子吸收测定。对两种方法的最佳条件进行了讨论。     

用HPLC测定当归中阿魏酸含量方法的研究

建立HPLC法测定当归中阿魏酸的含量方法。色谱柱采用Thermo ODS HY-PERSIL(250mm × 4.6 mm,5 μ m),流动相为乙腈-0.3%乙酸溶液(体积比为30 : 70),流速:1.0mL/min,检测波长:322nm,进样量为10μL,柱温:35℃。阿魏酸在0.1～10 μ g/mL范围内,线性关系良好(r= 0.9998)。平均回收率为101.58%,RSD为1.57%。该方法灵敏、准确、简便易行、重复性好,可用于中药当归药材的质量控制。     

畜产品中农药克伦特罗残留实用检测方法ELISA的测定

克伦特罗俗称"瘦肉精",是国家明令禁止使用在动物产品上的药物之一,目前ELISA(酶联免疫吸附法)是快速筛选检测动物肌肉、肝脏、尿液等样品中克伦特罗残留的方法之一,与高效液相色谱、气相色谱、气质联用仪器分析相比,它具有操作过程简单,样晶前处理快捷,可同时分析多个样品,分析时间短、成本低、敏感度高且对环境的污染少等优点,但在实际应用过程中涉及样品的处理、试剂准备、加样、温育、显色、结果判定等较多方面,其中任何一个步骤的操作不当都会影响最终的测定结果.为此,笔者于2006年7月进行了ELISA测定畜产品中克伦特罗残留最影响因子及不同试剂盒回收率差异度试验研究,取得了较为理想的结果,现将结果报道如下.     

混合碱中氢氧化钠和碳酸钠含量测定的影响因素与方法改进

混合碱是碳酸钠与碳酸氢钠或碳酸钠与氢氧化钠的混合物,测定混合碱的方法主要采用双指示剂法。指示剂的变色范围为pH=pkHIn±1,但由于人眼对各种颜色的敏感程度不同,加之两种颜色有互相掩盖的作用,影响观察,实测到的酸碱指示剂的变色范围会有所差异,从而引起滴定误差。文中对混合碱测定的称样量进行了改进,对测定混合碱的实验条件进行了探索,找出了最佳条件,收到了满意的效果。     

大枣中总黄酮和多糖的提取及含量测定

采用回流提取的方法,并结合大孔树脂吸附分离,富集并浓缩得到总黄酮和总多糖,用分光光度法测定总黄酮和总多糖含量,通过大孔吸附树脂分别得到含量为105.2%的总多糖及含量为5.3%的总黄酮,则大枣中总黄酮含量为0.11%,总多糖含量为16.43%。运用大孔吸附树脂可以同步提取大枣中的总多糖和总黄酮,对总多糖提取率高,有利于大枣的综合利用,为其质量控制提供参考。     

坚果与籽类食品中钼含量测定的方法探讨

分别用石墨炉原子吸收光谱法和电感耦合等离子体发射光谱法对坚果与籽类食品中钼含量进行测定,探讨了微波消解条件、升温条件、基体改进剂等对原子吸收光谱法的影响,以及微波消解条件、气流量条件选择对电感耦合等离子体发射光谱法的影响,分析讨论了两种测定方法的检测特点。     

两种测定高温合金中钛含量的方法对比

介绍了高温合金中钛含量测定的两种方法一二安替比啉甲烷吸光光度法和电感耦合等离子发射光谱法。本文通过对这两种方法进行了大量的对比试验,描述了两种方法的分析步骤,并且给出了电感耦合等离子发射光谱法测定高温合金中钛含量的最佳测试条件。两种分析方法都具有准确、相对标准偏差小的优点,对比吸光光度法,电感耦合等离子发射光谱法更加快速、方便。     

基于I3070的核电站板件测试方法研究

仪控设备是核电站分布最广,最主要的电仪设备。随着运行时间的增加,仪控设备的故障率也不断的增加,如何在出现故障之前发现故障点,减少由仪控板件老化引起的事故,成为一个必须解决的问题。本文基于MID技术,以安捷伦I3070为平台,以仪控板件FE7C21为例进行测试和分析,对于以后基于MID技术对核电厂电仪设备进行故障预诊断和在线维护,提高机组安全运行水平有重要作用。     

Experimental setup for testing and mapping of high temperature abrasion and oxidation synergy

Performance and lifetime of engineering materials at high temperature are affected by degradation of a material under wear and corrosion to a great extent. To assess the material performance at high temperature, the most detrimental processes and their interactions should be known and understood for materials selection and design of new advanced materials. The present study introduces an experimental setup for testing and mapping of high temperature abrasion taking into consideration the process of oxidation. A new design of a test rig has been developed at Tallinn University of Technology to provide synergy study of wear and oxidation and to improve the effectiveness of control and monitoring the mechanisms of materials failure at room and high temperatures (up to 1000 °C). Methodology for assessment and mapping of the effects of abrasion and corrosion on materials performance are presented along with some results obtained for high temperature abrasion of titanium carbide- and chromium carbide-based cermets as well as for steel.     

Uncertainty reducing method for the reference standards in gauge block comparator calibration

A simple method for reducing the uncertainty of reference standards has been proposed for gauge block comparator calibration. Errors due to the reference value of the length difference for mechanical comparator evaluation can be reduced by using the average of two reference values. Two reference values of length difference are obtained by the appropriate combination of three gauge blocks. Errors caused by reference gauges are canceled and averaged. An error reduction effect was successfully demonstrated using an actual mechanical comparator.     

A block‐on‐ring tribocorrosion setup for combined electrochemical and friction testing

The combined action of corrosion and wear can cause degradation of equipment, and thereby financial losses related to the renewal or repair of damaged equipment. In the food industry, metal degradation is a major concern since metal release eventually can cause health risks for consumers. This study describes a block‐on‐ring testing facility used to determine sliding wear, and additionally allowing for electrochemical measurements, such as potentiodynamic polarization curves and potentiostatic monitoring of current and potential. To verify the reliability and reproducibility of this block‐on‐ring tribocorrosion setup, the tribological and electrochemical behaviour of stainless steel sliding against a ceramic ring in sulphuric acid has been determined. Furthermore, a case taken from the food industry has been examined. The study shows that results made on the described block‐on‐ring testing facility are reliable and can provide improved information about material properties when the material is exposed to combined chemical and mechanical degradation. Copyright © 2007 John Wiley & Sons, Ltd.     

A measurement and testing method for lubrication regimes in gear transmissions

This paper describes the measurement and test results on oil film thickness conducted with a self-contained gear testing machine, with pandimensional power flow, using an improved method of discharge voltage measurement. A series of experiments were conducted in an attempt to measure and analyse the lubrication regimes of involute and double circular arc gear with different lubricants under various working conditions. A formula is provided for calculating oil film discharge voltage following the recorded output of a level recorder. Experimental results show that such an improved method for discharge voltage is suitable for measurement of film thickness, and that the results are in keeping with the minimum film thickness formula for a double circular arc gear deduced by the authors. The relations between film voltage and the gear parameters of load, rotation speed, lubricant and oil temperature, are also discussed. It is asserted that such a test system has more reliable performance and is more suitable for measuring and analysing the lubrication regimes of gear transmissions than are ordinary experimental systems.     

Air-coupled acoustic method for testing and evaluation of microscale structures

A noncontact testing and characterization approach for microscale structures based on air-coupled acoustic excitation and optical sensing is proposed and demonstrated. Using an air-coupled transducer to externally excite and a laser Doppler vibrometer/interferometer to capture transient displacement wave forms, the experimental approach results in a technique to determine mechanical properties of microscale structural elements. The effectiveness of this method has been demonstrated on commercially available microcantilever beams and microscale rotational oscillators fabricated for this study. The resonance frequencies and mechanical properties (Young's modulus and stiffness) extracted from the transient displacement wave forms have been compared, with good agreement, to computational and simplified analytical models for each case. It is also shown that the technique could serve to diagnose stiction problems of microscale structures. Some potential advantages of the approach described include the simplicity of the test setup, functionality at room conditions, noncontact and nondestructive operations, and repeatability and rapid turn-around time for the evaluation of modal parameters and mechanical properties of microscale structures.     

An engineering theory and an experimental method for contaminant wear testing

An engineering theory and experimental method for contaminant wear are proposed. By analysing the wear characteristics of hydraulic components, the contaminants' wear strength σ_m, wear factor ƒ_m, lubrication parameter λ_l, flexibility parameter λ_a, and material parameter λ_m, etc., can be defined. In addition, a new test apparatus, ‘MMU-5’, that can be used for studying wear properties under lubrication conditions, is reported. The friction pair of the tester is composed of two ring specimens. The most important aspect of this tester is that the gap between the two specimens can be adjusted from 0 to 100 microns. Using the tester, parameters such as λ_l, λ_a, λ_m, and ƒ_m, are investigated experimentally. Finally, the application of the corresponding engineering theory is assessed.     

A nondestructive method for express testing of condensed media in ecological monitoring

A nondestructive method for express testing of the state of condensed media is considered. The method is based on the developed new design of a small-sized nuclear magnetic resonance (NMR) spectrometer. The proposed engineering solutions and techniques have made it possible to detect weak-field NMR signals from various nuclei (that have magnetic moments) in a small (less than 0.3 cm³) volume of a condensed medium. This has extended significantly the capabilities of the NMRbased nondestructive method of express testing of condensed media, especially for the purposes of ecological monitoring of hard-to-reach territories. Results of experimental research of various media are presented.     

A setup for investigating the absorption spectra of dyes in excited states by the pump-probe method utilizing a fluorescence probe

An experimental setup for studying transient absorption spectra of organic dyes, which are excited with a high-power laser pulse, by the pump-probe method is described. Fluorescence of a mixture of organic-dye solutions is used as the source of probing radiation. The setup ensures recording of transient absorption in the spectral range 340–900 nm with a time resolution of up to 10 ns. The capabilities of the setup are demonstrated by an example of studying the singlet-singlet and triplet-triplet absorptions of organic dyes.     

高光谱遥感影像地面伪装目标检测方法的研究

根据光谱揭露伪装的检测机制,对目前国内外的许多绿色伪装材料和多种绿色植被背景的光谱特性进行了分析,探讨了实验目标光谱模拟伪装材料的检测技术.通过光谱特征选择及空间降维处理,建立了判别函数,确定了判别规则.寻找了适合区分人工目标与背景光谱的最佳分类特征和判别函数.