液化石油气中硫化物的测定方法

对液化石油气中硫化物的分析方法进行了评述。总硫测定多采用氧化微库仑法,灯法等。形态硫分析多采用气相色谱与硫选择性检测器结合的方法,这些检测器有火焰光度检测器（FPD）,原子发射检测器（AED）,硫化学发光检测器（SC）和脉冲火焰光度检测器（PFPD）等。其中硫化学发光检测器能较好地检测液化石油气中的各种形态硫化物。此外,液相色谱法,燃烧－离子色谱法,极谱法和核磁共振法等也可用于硫化物的分析。     

6441型火焰光度检测器的改装

为了改善和提高6441型火焰光度检测器的检测灵敏度,我们对该检测器的结构和组装方式作了一些改进. 不锈钢表面对硫存在严重吸附现象,因此从进样口到喷嘴出口全部改用玻璃组件,既减少了对硫的吸附,又减少了死体积,对提高测硫灵敏度十分利.为保持原色谱仪汽路、电路的完整性,对检测器的组装方式和安装位置作了必要的改动,并重新加工了少量部件.     

安捷伦推出新款ICP-MS系统 实现极低检测限

<正>近期,安捷伦科技(中国)有限公司于在京举行的"安捷伦原子光谱研讨会"上,正式推出了最新款"安捷伦8900串联四极杆ICP-MS系统"。这款新型电感耦合等离子体质谱系统能提供可控的反应化学过程,可为此前难以分析的诸如硫、硅和磷等元素提供极低检测限。另外,该新款ICP-MS系统还配备有快速检测器,可为单纳米颗粒检测相关应用树立全新标杆。     

裂解混合碳五中形态硫分布研究

利用极性色谱柱分离,选择性硫化学发光检测器(SCD)检测,根据不同硫化物的理化性质,结合液态标样定性,并采取总硫比对、脱硫验证等措施,得出了混合碳五中硫的大致形态分布;对部分硫化物进行了初步定量。     

基于多元非线性拟合方法的碳硫分析仪检测系统

为了满足对金属材料中碳硫元素含量的高精度和高灵敏度分析的需求,设计了高频红外碳硫分析仪.阐述了高频红外碳硫分析仪的结构和工作原理,并详细论述了检测系统的结构设计.通过采用高灵敏度红外热释电传感器、超窄带滤光片、表面镀金的特征光锥等设计,并将光锥与灵敏元真空封装在一起,减少了干扰气体成分的影响,提高了碳硫分析仪的检测灵敏...     

CHN—O快速元素分析仪管路的改装

对德国ＣＨＮ－Ｏ快速元素分析仪的吸收管路作了部分改装。实验结果表明，改装后的元素分析仪可成功地用于硫元素的分析测定，测定的精度和准确度可满意分析的要求，拓宽了仪器的应用范围。     

利用测硫仪测定磷石膏中的硫含量

利用焦炭作还原剂,用库仑法测硫仪测定磷石膏中的硫元素含量,并与重量法和原子吸收分光光度法两种测硫方法进行对比.结果表明,测硫仪法原理科学可行、操作简便,结果准确,相对偏差小于0.06%.本方法给出了磷石膏中硫元素测定的新途径,拓展了测硫仪的适用范围.     

电感耦合等离子体质谱测定硫的方法研究及应用进展

硫是矿石、化石燃料、蛋白质等的重要组成元素,与人类生活密切相关。近年来,随着质谱技术的发展,电感耦合等离子体质谱(ICP-MS)已成为硫测量和研究的重要手段,并在环境监测、食品安全、生命科学、环境地球化学等研究中显示出良好的应用前景。本工作综述了ICP-MS用于硫元素总量、多种形态、硫同位素测量技术方面的最新研究进展。     

GC—MIP与GC—FID的定量分析比较

微波诱导等离子体发射光谱(MIP-AES)是一种气相色谱多元素同时检测的选择性检测器.另外,通过检测碳、氢元素通道,它的险测功能与氢火焰离子化检测器(FID)相同,所以又是一种通用型检测器.本文通过测定不同化合物在这两种检测器上相对响应值的变化,比较了两种检测器的定量性能.结果表明,用MIP-AES进行定量分析,更简单、更准确.     

42CrMo钢电渣熔铸件成分分布的研究

研究了电渣熔铸对42CrMo钢元素的烧损规律,测定了42CrMo电渣熔铸件上不同部位元素的分布,用XRD测定了枝晶内和枝晶间元素的微观分布;用电解法和萃取法测定了电渣熔铸前后的夹杂物的含量,并对夹杂物特征进行了比较。结果表明:电渣熔铸件元素分布均匀,硫、磷等有害元素含量低。通过电渣熔铸,夹杂物含量大幅度降低,硫化物由0.014%下降到0.006%,氧化物由0.0065%下降到0.0044%～0.0047%,夹杂物总量由0.0205%下降到0.0105%。     

Angular correlations in detection of α-γ coincidences in the nanosecond tagged neutron technology

The characteristics of the setup for analyzing the elemental composition of organic substances using spectroscopy of γ rays induced by tagged neutrons with an energy of ～14 MeV in an inelastic neutron scattering reaction are discussed. An ING-27 D-T neutron generator with a built-in position-sensitive α detector, fast neutron and γ detectors, and a multichannel detecting system providing a subnanosecond time resolution are parts of the experimental setup. The correlation between the exit angle of a neutron and the number of the α pixel, as well as the anisotropy in emission of γ rays in the inelastic neutron scattering reaction, are measured, and the errors of these measurements are estimated.     

X-ray analysis without the need for standards

A technique has been developed for X-ray analysis using energy dispersive solid state detectors commonly used with electron microprobes or scanning electron microscopes (SEM). This technique does not require the use of analysed standard alloys, instead the elemental peaks are directly compared to each other and simple corrections applied to convert these to weight percentages. A new empirical table for X-ray fluorescence yields for the L X-ray spectra is also given in this article.     

Quantitative x‐ray microanalysis of model biological samples in the SEM using remote standards and the XPP analytical model

It is shown that accurate x‐ray microanalysis of frozen‐hydrated and dry organic compounds, such as model biological samples, is possible with a silicon drift detector in combination with XPP (exponential model of Pouchou and Pichoir matrix correction) software using ‘remote standards’. This type of analysis is also referred to as ‘standardless analysis’. Analyses from selected areas or elemental images (maps) were identical. Improvements in x‐ray microanalytical hardware and software, together with developments in cryotechniques, have made the quantitative analysis of cryoplaned frozen‐hydrated biological samples in the scanning electron microscope a much simpler procedure. The increased effectiveness of pulse pile‐up rejection renders the analysis of Na, with ultrathin window detectors, in the presence of very high concentrations of O, from ice, more accurate. The accurate analysis of Ca (2 mmol kg^?1) in the presence of high concentrations of K is possible. Careful sublimation of surface frost from frozen‐hydrated samples resulted in a small increase in analysed elemental concentrations. A more prolonged sublimation from the same resurfaced sample and other similar samples resulted in higher element concentrations.     

High-efficiency thermoluminescent detectors for measuring the absorbed ionizing radiation dose in the environment

A study has been conducted with the goal of comparing the characteristics of TLD-K detectors based on sodium silicate ceramics to the characteristics of monocrystalline lithium fluoride detectors that contain traces of titanium and magnesium (TLD-100), as well as anion-defected aluminum oxide (TLD-500), which are widely used in thermoluminescent dosimetry. Because they are soil-equivalent, SiO₂ detectors are well suited for measuring the absorbed radiation dose in soils. The results of the comparison indicate that TLD-K detectors are preferable to LiF detectors in environmental applications due to the better uniformity of the detector sensitivity in a batch, the wider range of measurable doses, and the lower threshold in determining small doses.     

Spatially resolved cathodoluminescence of luminescent materials using an EDX detector

Panchromatic cathodoluminescence (CL) maps were collected in a scanning electron microscope equipped with an EDX (energy dispersive x-ray analysis) detector. These CL maps can readily be correlated with elemental maps obtained by EDX. Although EDX detectors are designed to be insensitive to light and therefore not optimized for high sensitivity CL measurements, high-resolution images can be obtained from luminescent materials without the need for additional hard- or software. The method was tested on highly luminescent BaAl₂S₄ : Eu²⁺ thin films that have a potential use in flat panel displays. The spectral response and linearity of the overall system was determined by means of monochromatic light sources, illuminating the sample through an optical fibre. We studied the response of the EDX detector to the intensity of the incoming light as well as the influence of the detector settings. The observations were explained by numerical simulations.     

A new method of imaging particle tracks in solid state nuclear track detectors

Solid state nuclear track detectors are used to determine the concentration of α particles in the environment. The standard method for assessing exposed detectors involves 2D image analysis. However 3D imaging has the potential to provide additional information relating to angle as well as to differentiate clustered hit sequences and possibly energy of α particles but this could be time consuming. Here we describe a new method for rapid high-resolution 3D imaging of solid state nuclear track detectors. A 'LEXT' OLS3100 confocal laser scanning microscope (Olympus Corporation, Tokyo, Japan) was used in confocal mode to successfully obtain 3D image data on four CR-39 plastic detectors. Three-dimensional visualization and image analysis enabled characterization of track features. This method may provide a means of rapid and detailed 3D analysis of solid state nuclear track detectors.     

Measuring the performance of scanning electron microscope detectors

A simple digital method of measuring the performance of detectors in the scanning electron microscope (SEM) is described. The value derived is absolute and can therefore be used to compare both different detectors on the same instrument as well as different detectors on different instruments. The technique can be applied to secondary electron, backscattered electron, and energy-dispersive x-ray detectors. Examples are given of measurements made on a variety of commercial detectors installed on a number of current SEMs.     

Vacuum photodiode detector array for broadband UV detection in a tokamak plasma

An array of vacuum photodiode detectors has been used to monitor discharge equilibrium, stability, and cleanliness in the Macrotor tokamak. These detectors use the photoelectric effect on small tungsten plates to measure UV emission in the band lambda approximately 200-1200 angstroms, and so are sensitive mainly to impurity line radiation in Macrotor. The response of this system to controlled impurity contamination experiments and to disruptions is described. The design, construction, and background problems associated with these detectors are discussed in detail.     

Performance Comparison of Automated Induction-Based Algorithms for Landmine Detection in a Blind Field Test

Wideband Electromagnetic Induction (EMI) data provides an opportunity to apply robust statistical signal processing techniques to potentially mitigate false alarm rates in real-time landmine detection. This paper explores the application of matched subspace detectors (MSDs) and Support Vector Machines (SVMs) to this problem. A library of landmine responses is generated from a set of calibration data and a bank of matched subspace detectors, each designed to detect a specific mine type, is developed. Support vector machines are also considered for target/clutter discrimination. These are developed based on landmine signatures, decay rate estimates, and the outputs of matched subspace filter banks. Synthetic data sets are generated and matched subspace detectors and support vector machines are trained using this synthetic data. Receiver Operating Characteristics (ROCs) for matched subspace detectors and support vector machines are presented for both experimental and simulated data sets. The results indicate that substantial reductions in false alarm rates can be achieved using these techniques, but that simulated data sets may not provide accurate predictors of performance.     

Influence of the number of detectors by laser scattering method for estimation of particle size

Effect of the number of detectors on an inversion problem of a scattering pattern by laser scattering method based on Mie scattering model has been investigated. The influence of the number of detectors is obtained by comparing a given size distribution and a calculated size distribution by computer simulation and experimental method. An observing range of scattering angles is from 0.0007 to 2.5 rad. A non-linear iteration method is used for calculating particle size distribution. The number of detectors is changed from 6 to 81 elements by the computer simulation. The algorithm of the inversion problem is applied with mean diameters of log-normal distribution in a range from 0.546 to 214 μm at standard deviation of 0.27 and 0.68. Experimental results of certified mono-disperse polystyrene latex standards and a poly-disperse aluminum sample are obtained with 21, 41, and 81 elements detector, respectively. All tests are performed under conditions at diluted aqueous suspensions. Narrow size distribution is influenced by the number of detectors compared with wide size distribution. Not the number of physical detectors but the number of useful detectors affects the algorithm of the inversion problem. When the detector elements are over 20, the influence of the number of detectors is decreased.