MSC理论研究固体CS2的实验谱

用近边Ｘ射线吸收精细结构（ＮＥＸＡＦＳ）的多重用射集团（ＭＳＣ）方法对固体ＣＳ２的硫Ｋ－边ＮＥＸＡＦＳ实验谱进行了详细的研究，结果表明：１．确认Ｋ－边ＮＥＸＡＦＳ实验谱的主体结构是双σ键和π２．固体ＣＳ２中间时存在的硫的单键和双键和对应的两种吸收谱；３．π几乎全由双键所贡献，而双σ则分别由单键和双键所贡献；４．ＮＥＸＡＦＳ实验谱是两种吸收谱的叠加。     

EXAFS研究负载型Ni／SiO2的区域结构

实验结果表明改进的实验室ＥＸＡＦＳ谱仪测试Ｎｉ箔的Ｋ吸收得到的ＥＸＡＦＳ谱与同步辐射上测量Ｎｉ箔得到的ＥＸＡＦＳ谱相近，利用实验室ＥＸＡＦＳ方法也可开展较好的结果测量研究，在ＳｉＯ２粉末载体上Ｎｉ负载量变化的ＥＸＡＦＳ结果表明，随着Ｎｉ负载量的降低，Ｎｉ的径向结构函数主配位峰的位置Ｒ＝０．２２０ｎｍ保持不变，但振幅强度逐渐降低。负载量从Ｎｉ箔到２．５％Ｎｉ／ＳｉＯ２，无序度因子σ由０．００６８ｎｍ     

工业中的现代表面分析技术(Ⅰ) 主要仪器和方法简介

本文扼要地介绍了几种工业中常用的现代表面分析仪器和方法，如俄歇电子谱（ＡＥＳ）、Ｘ－射线光电子谱（ＸＰＳ）［或称化学分析用电子谱（ＥＳＣＡ）］、二次离子质谱（ＳＩＭＳ）等的基本工作原理、仪器结构、使用方法及其特点，简单讨论了与表面分析有关的超高真空技术、样品表面的清洁、离子束溅射及无损检测等问题．     

PAN基活性炭纤维的表面及其孔隙结构解析

通过氮吸附等温线、Ｘ射线光电子能谱以及扫描电子显微镜（ＳＥＭ）对聚丙烯腈（ＰＡＮ－Ｐｏｌｙａｃｒｙｌｏｎｉｔｒｉｌｅ）－基活性炭纤维（ＡＣＦ－Ａｃｔｉｖａｔｅｄ Ｃａｒｂｏｎ Ｆｉｂｅｒ）的表面和孔隙结构进行了分析，结果表明吸附测量可以提供有关碳质吸附剂的孔结构复杂性；通过ＸＰＳ对ＰＡＮ基ＡＣＦ的表面官能团的种类及含量进行了表征，由ＳＥＭ对ＰＡＮ基ＡＣＦ的表面以及断面的孔隙结构进行直拉观察，提供了     

一种新型物质结构分析手段———同步辐射XAFS方法

ＸＡＦＳ方法是一种新型物质结构分析手段，近年来已成为非常活跃的学科领域．文章简要介绍了ＸＡＦＳ的物理概念，同步辐射ＸＡＦＳ实验方法的基本原理及实验装置，我国建造的第一个也是目前唯一的同步辐射ＸＡＦＳ实验系统的主要物理参数、运行状况，以及我国ＸＡＦＳ研究工作的进展     

一种可用于测量薄膜材料的实验室EXAFS方法

本文介绍了利用从薄膜衬底反射的Ｘ射线，在常规实验室条件下实现了对薄膜材料的ＥＸＡＦＳ测量．我们用该方法在 Ｄ／ｍａｘ－ｒＢ１２ｋＷ转靶Ｘ射线衍射仪上得到的纯 Ｃｕ薄膜的 ＥＸＡＦＳ测量结果和常规透射法的测量结果一致．这表明该方法是可靠的．     

LOW ENERGY TRIPLE DIFFERENTIAL CROSS SECTIONS FOR ELECTRON IMPACT IONIZATION OF HYDROGEN

ＬＯＷＥＮＥＲＧＹＴＲＩＰＬＥＤＩＦＦＥＲＥＮＴＩＡＬＣＲＯＳＳＳＥＣＴＩＯＮＳＦＯＲＥＬＥＣＴＲＯＮＩＭＰＡＣＴＩＯＮＩＺＡＴＩＯＮＯＦＨＹＤＲＯＧＥＮＣｈｅｎＺｈａｎｇｊｉｎａ，ｂＸｕＫｅｚｕｎｂＸｕＦｕｘｉｎａａＤｅｐａｒｔｍｅｎｔｏｆＰｈｙ...     

THE EXCESS HEAT EXPERIMENTS ON COLD FUSION IN TITANIUM LATTICE

ＴＨＥ　ＥＸＣＥＳＳ　ＨＥＡＴ　ＥＸＰＥＲＩＭＥＮＴＳ　ＯＮ　ＣＯＬＤ　ＦＵＳＩＯＮ　ＩＮ　ＴＩＴＡＮＩＵＭ　ＬＡＴＴＩＣＥＴＨＥＥＸＣＥＳＳＨＥＡＴＥＸＰＥＲＩＭＥＮＴＳＯＮＣＯＬＤＦＵＳＩＯＮＩＮＴＩＴＡＮＩＵＭＬＡＴＴＩＣＥ￥ＺｈａｎｇＱｉｎｇ...     

物质族质量谱计算程序

文给出了一种个根据王德奎先生确定的公式计算物质族基本粒子质量谱的Ｃ语言程序，并将计算结果用ＦＵＸＢＡＳＥ列表显示以便用国外实验室有关数据验证其正确性。     

DEUTERIUM INFLUX PROFILE ALONG THE APEX OF THE UPPER X-POINT TILES IN JET

ＤＥＵＴＥＲＩＵＭＩＮＦＬＵＸＰＲＯＦＩＬＥＡＬＯＮＧＴＨＥＡＰＥＸＯＦＴＨＥＵＰＰＥＲＸ－ＰＯＩＮＴＴＩＬＥＳＩＮＪＥＴ￥Ｙ．Ｋ．Ｚｈｕ（ＳｏｕｔｈｗｅｓｔｅｒｎＩｎｓｔｉｔｕｔｅｏｆＰｈｙｓｉｃｓ，Ｐ．Ｏ．Ｂｏｘ４３２，Ｃｈｅｎｇｄｕ６１００４１...     

A spectroscopic study of uranium(VI) interaction with magnetite

The uranium sorbed onto commercial magnetite has been characterized by using two different spectroscopic techniques such as X-ray photoelectron spectroscopy (XPS), and extended X-ray absorption fine structure (EXAFS). Magnetite samples have been put in contact with uranium(VI) solutions in conditions in which a high uranium uptake is expected. After several days, the magnetite surface has been analysed by XPS and EXAFS. The XPS results obtained are not conclusive regarding the uranium oxidation state in the magnetite surface. On the other hand, the results obtained with the EXAFS technique show that the uranium-magnetite sample spectrum has characteristics from both the UO₂ and schoepite spectra, e.g. a relatively high coordination number of equatorial oxygens and two axial oxygens, respectively. These results would indicate that the uranium sorbed onto magnetite would be a mixture of uranium(IV) and uranium(VI).     

α能谱峰形函数及其拟合参数初始值获取

(1. 西南科技大学 核废物与环境安全国防重点学科实验室, 四川 绵阳 621010;2. 四川理工学院 化学与环境工程学院, 四川 自贡 643000;3. 成都理工大学 地质灾害防治与地质环境保护国家重点实验室, 成都 610059;4. 中国工程物理研究院 核物理与化学研究所, 四川 绵阳 621900) 根据能谱的形成机理,建立了一种能谱峰形函数,提出基于矩估计法确定该峰形函数的拟合参数初始值的方法。以数理统计为基础,分别通过峰形函数和离散谱峰数据计算均值、方差和三阶中心矩建立方程组求解获取拟合参数的初始值。通过连续气溶胶检测仪探测的氡子体能谱和低本底能谱仪探测的238Pu面源能谱对该峰形函数模型和初始值获取方法进行了测试。结果表明:从低重合度到高重合度,该峰形函数模型都能得到较好的应用;基于矩估计法确定该峰形函数的参数初始值能够使该峰形函数较好地拟合能谱数据。该方法在采用计算机自动能谱拟合分析中具有较强的实用性。     

阻尼最小二乘算法CARS光谱温度拟合

为了解决相干反斯托克斯喇曼散射（CARS）光谱CARSFT计算程序在温度拟合过程中,对初值依赖大、测量光谱信噪比差、不易收敛的问题,通过分析非线性迭代算法,采用了阻尼最小二乘算法对氮气CARS光谱进行温度拟合。针对CARS理论光谱计算公式较为复杂的特点,采用数值差分的方式来获得迭代计算时所需要的设计矩阵。分析了横向偏移、纵向偏移和温度三个主要参量对拟合残差的影响,发现纵向偏移的初值设置对温度拟合影响较大。拟合温度2000 K时的标准理论CARS光谱,设置偏离较大的初始值,采用阻尼最小二乘法获得了较好的结果。迭代计算167步后,温度拟合为2 005.6 K,残差为0.027 463。拟合光谱信噪比较差的CARS光谱,阻尼最小二乘法也能稳定收敛。结果验证了阻尼最小二乘法对初值的依赖不大,并且当拟合谱信噪比较差时也能收敛,可用于在恶劣环境下CARS测量光谱的拟合。     

能量分辨率对EXAFS的影响

测量EXAFS谱时,系统的能量分辨率是影响其结果的重要因素。本文提出了分辨率影响结构参数的计算方法,以Ge,Ni样品为例,测量及计算了不同分辨率下的结构参数的差异。测量结果与计算结果符合得很好,讨论了分辨率如何影响EXAFS谱及结构参数,给出了修正方法。 关键词：     

A comparative study of the spectra recorded at RRCAT synchrotron BL-8 dispersive EXAFS beamline with other beamlines

The aim of the present work is to make a comparative study of the EXAFS spectra recorded at the BL-8 dispersive EXAFS beamline at 2 GeV Indus-2 synchrotron source at RRCAT, Indore (India) with those recorded at other synchrotron EXAFS beamlines, viz., X-19A at NSLS, BNL (USA), EXAFS wiggler beamline 4-1 at the SSRL (USA) and beamline 11.1 at ELETTRA (Italy). For this purpose, EXAFS spectra at Cu K-edge in copper metal have been recorded at these four beamlines. Further, EXAFS spectra at Cu K-edge in a copper complex have also been recorded at BL-8 beamline and beamline 11.1 at ELETTRA (Italy). The obtained experimental μ(E) data have been background-subtracted and then normalized. The normalized data have been then converted to χ(k) data, which have been Fourier-transformed and then fitted with the theoretical model, thereby yielding different structural parameters. It has been shown that the results obtained from the EXAFS spectra recorded at the BL-8 beamline are comparable with those obtained from other synchrotron EXAFS beamlines and also with the crystallographic results reported by earlier workers. The reliability, usefulness and data quality of the BL-8 beamline have been discussed.     

累积量展开方法在EXAFS数据分析中的应用

将累积量展开方法用于EXAFS数据分析,比通常所用的标样比较法求原子间距和配位数更为合理,而且精度高。本文给出了用累积量展开方法求结构参数的一般表达式,对GeO₂玻璃的EXAFS数据实际进行了分析,并与一般方法的分析结果进行了比较。     

实验室EXAFS测量中单色器晶体二级衍射的应用

本文研究了实验室EXAFS测量中,应用单色器晶体二级衍射的有关问题,当测定的能量范围内,X射线连续谱上存在杂质发射线时,将导致测定吸收谱精细结构的畸变,研究了对这种谱线畸变进行修正的方法,并对采用晶面二级衍射测定时,EXAFS谱振幅降低的情况下如何求得正确的结构参数进行了讨论。 关键词：     

Determining the radial pair distribution function from X‐ray absorption spectra by use of the Landweber iteration method

The Landweber iteration approach is used to construct the radial pair distribution function (RPDF) from an X‐ray absorption (EXAFS) spectrum. The physical motivation for the presented investigation is the possibility to also reconstruct asymmetric RPDFs from the EXAFS spectra. From the methodical point of view the shell fit analysis in the case of complicated spectra would be much more eased if the RPDF for the first shell(s) are computed precisely and independently. The RPDF, as a solution of the fundamental EXAFS integral equation, is examined for theoretical examples, and a detailed noise analysis is performed. As a real example the EXAFS spectrum of curium(III) hydrate is evaluated in a stable way without supplementary conditions by the proposed iteration, i.e. by a recursive application of the EXAFS kernel.     

Extended X-ray-absorption fine structure of mixed-coordination systems

An analysis method of the extended x-ray absorption fine structure (EXAFS) for mixed-coordination systems (MCS) is provided to determine structure parameters of the same type of atoms located at different coordination sites and proportion of them. It's demonstrated that if the effects of different sites on EXAFS amplitudes are ignored, the coordination numbers gotten from EXAFS analyzing must be wrong mostly. The method has been well tested by analyzing a known structure Gd₃Ga₅O₁₂ (GGG) crystal in which the Ga atoms have two different coordination sites. Li₂O-ZnO-GeO₂ glass system is also analyzed by means of the EXAFS method for MCS. Two different coordination sites for Ge atoms in the glasses. are found and the occupancies of them and the structure parameters are determined.