X射线荧光光谱—玻璃熔融制样法分析铁矿中成分和微量成分

采用ｎ样品：ｍ熔剂为１：２的低稀释比玻璃熔融技术，Ｘ射线荧光法测定铁矿中的主成分和微量成分，既提高了灵敏度又消除了不均质效应，与粉末压片方法相比，对硫的分析得到了更好的结果，使用基本参数程序建立了一新的校正方法来校正由于烧失量，烧增量，稀释比或熔剂挥发而导致的分析误差。     

催化剂原料高岭土的XRF分析

本文拟定了Ｘ－射线荧光分析催化剂原料高岭土中Ａｌ２Ｏ３、ＳｉＯ２和杂质成分的方法。根据精矿中分析元素含量范围和基体效应的估计，分别合成了Ａｌ２Ｏ３－ＳｉＯ２二元系和含所有杂质成分的两套标准系列，测定烧失量后的粉末样品。用本文改进的少量粉末样品备法压片，各组分含量由校正曲线直接求取而不需基体校正。与溶片法相比，本法不仅在溶剂杂质和稀释比高岭土精矿中微量成分测定的影响。     

X射线荧光光谱法测定烧结锰矿中的主次量成分

采用四硼酸锂和偏硼酸锂混合熔剂熔融法制样,X射线荧光光谱法测定了烧结锰矿中的MnO、Fe2O3、SiO2、Al2O3、TiO2、CaO、MgO、SO3和P2O59个主次量成分。以12个锰矿石标准样品建立校准曲线,用理论α系数法校正基体效应。测定烧结锰矿样品各成分的相对标准偏差(RSD,n=10)在0.26%—3.94%之间。用实际样品验证,测定结果与化学方法的测定值相符。与化学法相比,该方法具有快速、简便、精密度好和准确度高等优点。     

基于主成分分析的不同预处理方法对关节软骨分类的影响

本文采用不同方法对来自正常和病变关节软骨样本的红外光谱进行预处理,而后利用主成分分析对关节软骨进行鉴别分析。首先对关节软骨切片实现傅里叶变换红外光谱采集,其次分别采用基线校准、标准化、多元散射校正和标准正态变量变换对软骨的红外光谱进行预处理,然后对原始光谱(矩阵)以及预处理光谱进行主成分分析,根据得分矩阵对样本进行分类分析。结果表明:预处理方法结合主成分分析可以更好地对正常和病变关节软骨样本进行分类,而且多种预处理方法的结合可以更好地增强样本间的区分度。另外,针对关节软骨样本,多元散射校正比标准正态变量变换具有更好的增强效果。     

基于ATR校正的红茶成分近红外光谱无损检测

采用偏最小二乘(PLS)算法结合衰减全反射(ATR)校正提取近红外光谱的特征信息,建立红茶含水率、茶多酚、游离氨基酸和酚氨比的预测模型。与原始光谱建模相比,在保证预测精度的前提下,采纳的主成分数更少,降低了预测模型的复杂性。红茶含水率、茶多酚、游离氨基酸和酚氨比预测集相关系数(R_p)和预测均方差(RMSEP)分别为0.994、0.960、0.944、0.922和0.182、0.523、0.184、0.556。通过配对双边t-检验,该方法与标准法测定结果无显著性差异。结果表明,偏最小二乘法结合ATR校正能够有效地简化红茶含水率、茶多酚、游离氨基酸和酚氨比的预测模型,实现红茶品质成分的快速检测,为评估红茶质量优劣提供了新的方法。     

X射线荧光光谱法同时测定煤灰中的12种成分

采用熔融制样法,用X射线荧光光谱法同时测定煤灰中的常量、少量和微量成分SiO₂,Al₂O₃,Fe₂O₃,CaO,SO₃,TiO₂,K₂O,Na₂O,P₂O₅,Mg_O,MnO,BaO。选用混合熔剂并加入氧化剂的方式降低熔融温度,解决了硫的准确测量问题。同时通过选用土壤等标准样品解决了煤灰成分标准样品不足的问题。应用可变理论α系数及固定α系数法进行基体效应校正,所得结果与化学法的分析结果相符合。     

X荧光光谱法分析LF-VD精炼炉炉渣

采用X荧光光谱仪分析LF-VD精炼炉炉渣中TFe,CaO,MgO,Al2O3,SiO2,TiO2,MnO,P2O5等8个组分。因精炼炉渣中氧化钙含量高,我们选用了12个国家级、部级炉渣标准样品,再添加光谱纯试剂配制了数点合成标样,适应氧化钙、三氧化二铝、二氧化硅含量范围跨度较大的样品分析,同时使得分析曲线点分布均匀。用四硼酸锂作熔剂,高温熔融制样。进行了脱模剂、熔融温度及稀释比等制样条件的选择试验。采用PH模式、理论α系数校正基体的吸收增强效应,进行了方法的精密度及准确度试验。与化学法对照,各组份的定量分析结果令人满意。方法准确、快速、简便。     

ICP-AES可变浓度法测定PtIr和PdIr系列合金中的次成分Ir及杂质元素

本工作采用不称准样和不准确稀释的可变浓度的ICP-AES法,测定了PtIr_(5·30),PdIr_(5·30)系列合金中的次成分Ir和十二个杂质元素。Pt基和Pd基对待测元素的影响,采用等效浓度差减法进行校正。方法简便、快速、准确,并能节省大量的铂和钯。     

X射线荧光光谱法测定冶金熔剂的方法研究

采用折算方式进行X射线荧光光谱测定冶金熔剂,解决了该方法没有标准样品及烧失量大的难题,得到满意的分析结果。     

钛酸钡瓷粉样品中多元素的X射线荧光光谱分析

本文采用四硼酸锂和偏硼酸锂混合熔剂熔样，人工合成法制备钛酸钡瓷粉XRF标样，选用Sr和Ca内标元素消除制样和仪器漂移产生的误差，建立了无须进行烧失量校正的X射线荧光光谱分析钛酸钡瓷粉样品的分析方法，分析结果的准确度和精密度符合生产要求，也适用于其它含B元素样品的分析。     

水下切伦科夫光光斑的蒙特卡罗模拟

分别采用分出截面法和积累因子法计算了水下放射性源透过一次屏蔽体的中子与射线的剂量场分布,并在这些分布条件下,利用Geant4软件射线在穿越二次屏蔽体后继而穿越后续水层,计算出在3 m水层中产生的切伦科夫(Cherenkov)光通量分布和光谱分布。以纯水为传播介质,在考虑Cherenkov光在不同水层中传播所造成的几何衰减和水层吸收等因素后,由计算获得了Cherenkov光光斑大小和强度分布。     

Effect of stoichiometric mixture fraction on soot fraction and emission spectra with application to oxy-combustion

Many proposed oxy-combustion concepts for carbon capture incorporate the recycling of flue gas which is used as a dilution gas to aid in the control of temperature and heat flux. Improvements in efficiency may be realized by significantly reducing the recycle flue gas (RFG), however, in application, care must be taken to avoid excessive radiant heat flux and gas temperature. One of the features oxy-combustion, unlike air-fired combustion, is that the oxygen and dilution gases are initially separated. RFG can, for example, be strategically blended with either the fuel stream, or oxidizer stream, or both, which affects the stoichiometric mixture fraction, Z_st. In this work, the effects of the amount of dilution, or RFG, and Z_st on soot fraction are experimentally investigated in a laminar coflow flame. Carbon dioxide is employed as the dilution gas to simulate the recycling of dry flue gas. Soot fraction and temperature are quantitatively determined by a flame image processing technique. In addition, the visible and near-IR emission spectra are given. When dilution, or RFG, is reduced, while holding Z_st constant, soot formation and thermal radiation increase due to higher temperature. However, high temperature flames with reduced or zero soot are achieved by increasing Z_st via the combination of fuel dilution and oxygen enrichment. This study highlights the inherent flexibility of oxy-fuel combustion, which offers the opportunity to control flame temperature and gas volume while independently controlling soot formation and radiant heat transfer.     

Quantitative analysis of chromite ores using glass discs in moderate dilutions of lithium tetraborate by x‐ray fluorescence spectrometry

A method for the quantitative analysis of chromite ores by x‐ray fluorescence spectrometry using beads is proposed. The work concerned the serious problems caused by the refractory nature of these materials which prevents the use of glass discs in x‐ray fluorescence. An in‐depth study was done to optimise the variables which influence the glass disc formation process. Sufficiently homogeneous glass discs were obtained under the following experimental conditions: lithium tetraborate as flux with moderate sample dilution (1:40), with the addition of one or two drops of LiBr solution(250 g l^?1), at a temperature of 1200 °C for 30 min. The qualitative and semiquantitative results for the chromite ores provided synthetic standards based on combinations of similar reference materials and different pure ignited oxides. These standards were used to obtain the calibration curves for Cr, Si, Al, Fe, Ti, Ca, Mn, Mg, Na and K oxides, with root mean square error always below 0.357. The calibration curves were used in the quantitative analysis of chromite ores with satisfactory accuracy, justifying compensation of the interelemental effects. The suggested method is an efficient solution to the problems with the quantitative analysis of this type of material by XRF. Copyright © 2006 John Wiley & Sons, Ltd.     

层流高温部分电离气体射流热流密度分布动态测量与分析

采用表面中心位置装有铜探头的平板,对射入大气环境的层流纯氩高温部分电离气体射流冲击平板的热流密度进行了动态测量,分析了测量条件对热流密度及其分布特性测量结果的影响。同时,研制了嵌有铜探头的小尺寸杆状热流探针,在小扰动条件下测量了射流的热流密度分布。结果显示层流等离子体射流具有稳定的能流密度,探针的移动速度对射流中心区域的热流密度测量结果影响很大。     

Development of undersized (12.5 mm diameter) low‐dilution glass beads for X‐ray fluorescence determination of 34 components in 200 mg of igneous rock for applications with geochemical and archeological silicic samples

A low‐dilution, undersized (12.5 mm diameter) glass–bead technique was developed for X‐ray fluorescence determination of 34 components (Na₂O, MgO, Al₂O₃, SiO₂, P₂O₅, K₂O, CaO, TiO₂, MnO, Fe₂O₃, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Cs, Ba, La, Pr, Nd, Sm, Gd, Dy, Er, Yb, Hf, W, and Pb) in precious silicic samples for geochemistry and archeology. This preparation was consolidated based on the properties of the specimen, including disk formability and detachability from a small crucible, through variation of the amounts of the two samples (basaltic and granitic rocks) and releasing reagent. The specimen was prepared by fusing a mixture of 200 mg of powdered sample, 200 mg of lithium tetraborate as a flux, and 60 µl of 18.42 mass% lithium chloride solution as a releasing agent in a small platinum crucible. Calibration curves were drawn using synthetic calibration standards, which were prepared by compounding chemical reagents, such as oxides, carbonates, and diphosphates containing analytes. The calibration curves showed good linearity with correlation coefficient values greater than 0.990. Using the proposed method, we determined 34 components in five igneous rock reference samples. The results were in agreement with the recommended values, accounting for uncertainties. With this method, preparation requires only small amounts of the powdered sample and alkali flux; however, still allowing for determination of many analytes, which is advantageous when dealing with limited quantities of precious samples. The present method has potential applications in the chemical characterization of various geological and archeological samples. Copyright © 2015 John Wiley & Sons, Ltd.     

启明星Ⅱ次临界非稳态热中子注量率测量

中子注量率及分布是反应堆的重要参数,本工作通过核数守恒在非稳态情况下的推导和求解,从理论上论证了次临界反应堆非稳态情况下中子注量率测量的可行性。将活化法和固体径迹法有机结合,利用固体径迹探测器标定活化片的测量数据,测量了启明星Ⅱ零功率装置的He-3管实验孔道内及反应堆外壁的中子注量率的分布,并与模拟计算结果进行了比较,利用MCNPX程序得到的模拟计算结果与实验结果的趋势一致,证明了该测量方法可以测量低通量的中子注量率,可实现反应堆不同时刻、不同位置的中子注量率测量,为CiADS技术的研发提供了实验数据与技术支撑。Neutron flux measurements were carried out at VENUS-Ⅱ lead-based zero power reactor by neutron activation method combined with solid-state nuclear track detectors (SSNTD). This experimental method was proposed based on the principle of nuclear number conservation when a foil was irradiated in an unsteady-state neutron field. By this method, thermal neutron flux distributions inside the He-3 duct were measured when VENUS-Ⅱ was operated under unsteady-state. The neutron flux distributions were also calculated with MCNPX code and were consistent with the experimental data. In addition, the neutron fluxes in the outer layer of VENUSⅡ were measured under steady-state. These results would benefit the further study of experimental methods for neutron flux measurement and provide important support for the design of CiADS.     

DSMC方法下给定热流边界条件的实施

本文详细讨论了DSMC方法中流体温度、能量及边界热流的统计方法,发展了一种从边界热流求得与壁面碰撞分子反射速度的方法。该方法被称为逆温度抽样算法(ITS,Inverse Temperature Sampling)方法。在此基础上,本文发展了DSMC方法中壁面处给定热流边界条件的实施方法。计算结果表明: ITS方法能准确抽样反射分子的特征温度,进而求得分子反射速度。基于该方法的给定热流边界条件可以准确求得壁面处温度分布,以及流场内的压力、速度。     

高温超导磁通跳跃过程中的磁致伸缩效应

文中基于超导磁通动力学理论,考虑电磁力与热激活对磁通运动的影响,基本模型包括由等效电阻率随超导体温度和磁场变化的磁通扩散方程,以及比热随超导体温度变化的热传导方程组成.在此基础上,用数值方法求解了这组非线性磁热耦合方程,主要研究了有磁通跳跃状发生状态时环境温度和外磁场速度对于高温超导磁致伸缩的影响.结果表明:磁通进入超...     

A simple method for quantitative analysis of elements by WD‐XRF using variable dilution factors in fusion bead technique for geologic specimens

A common approach in the quantitative analysis of geological samples by X‐ray fluorescence is to establish calibration lines for elements of interest by using several reference materials (RMs) and/or the combination of RMs and pure chemicals. Herein, we introduce an alternative to use only two RMs, to establish a calibration application. Variation of the dilution factor is employed to generate a dynamic range of concentrations for each RM and to evenly furnish the calibration lines to analyze certain matrices. A wide range of dilution factors were employed from 2–54 times dilution (with respect to the flux to sample ratios). Calibration lines for the major elements including: Si, Al, Ca, Fe, Mg, Na, Mn, and Ti show an extremely high level of linearity with all elements. R² values greater than 0.9990 were obtained for each analyzed element. The calibration application was validated by checking against a variety of geological RMs including petroleum and carbonate rich shale (SGR‐1), Muscovite rich marine shale (SBC‐1), metamorphic rock (SDC‐1), carbonatite (COQ‐1), and types of igneous rocks (GSP‐2, BCR‐2, AGV‐2, QLO‐1, and W‐2). Mixtures of Alumina and Silica (ARG‐1 and ARG‐2) and pure SiO₂ beads were also analyzed to further check the application. Rigorous statistical analysis on the RMs confirms the reliability of the calibration application for the employed matrices. Copyright © 2016 John Wiley & Sons, Ltd.