X-射线粉晶衍射谱图的计算机模拟

编写了一个FORTRAN程序,用于从单晶结构计算粉晶X射线衍射数据,并进一步用ORIGIN软件绘制出粉晶衍射图谱,选择了13个代表性经典化合物进行计算,结果与粉晶卡片上的实验数据相当一致,本文模拟方法,即可弥补粉晶图谱缺乏的不足,也可用于]校验粉晶衍射实验结果的可靠性。     

高温X射线衍射法鉴别珍珠粉及贝壳粉

用高温X射线衍射法(XRD)研究了珍珠粉及贝壳粉中碳酸钙的相变过程。结果表明:随着试验温度的升高,上述2种样品均发生文石型向方解石型的相变,但相变程序不同;当温度从室温升至330℃,贝壳粉中方解石的质量分数由0.5%增至25.5%,而珍珠粉中方解石的质量分数则由5.0%增至8.1%。根据测定温度条件试验并综合考虑其它因素选择测定温度为330℃。试验了珍珠粉和贝壳粉混合样品中碳酸钙的上述2种晶体的相变情况,结果发现:样品中方解石的含量与其混入的贝壳粉含量呈线性关系,表明两者的混合并不影响其相变机制。在相同试验温度条件下,珍珠粉的相变程度明显低于贝壳粉。利用这一现象,可以用高温XRD快速而准确地对珍珠粉和贝壳粉进行鉴别。     

钛酸锶基陶瓷材料中微量物相鉴定

对具有优良介电性能的高频热补偿多层陶瓷电容器材料（Sr，Ca）TiO3系统进行了研究；X射线粉末衍射法研究表明当瓷料中钛酸锶烧块（简称ST）与钛酸钙烧块（简称CT）摩尔比为nST：nCT≈70：30时，主晶相为具有钙钛矿型结构的（Sr，Ca）TiO3固溶体；微量次晶相为具有钨青铜结构的新化合物铌酸钛钡Ba6Ti2Nb8O30，正交偏光显微分析及材料的介电性能分析进一步验证了这一微量次晶相的存在。     

纳米钛薄膜的XPS研究

用 XPS分析了三种纳米钛薄膜表面和经 Ar 溅射后内部碳、氧、氮、钛等的含量和化学态。发现三种薄膜表面碳、氧含量完全一致 ,碳为石墨态 ,氧为吸附态的水。薄膜内部碳、氧、氮的化学态主要为 Ti C、Ti O2 、Ti N。随着分析深度的增加 ,薄膜内金属钛的原子百分比浓度不断增加并逐渐趋于恒定。镀膜时真空度的提高有利于减少碳、氧、氮的污染。Ar 溅射所镀的膜与电子枪所镀的膜相比 ,晶粒尺寸小 ,在表面至浅表层内氧的含量有明显差异。     

含过量钛的 BaO·TiO粉末的高温X射线衍射研究

本文采用高温X射线衍射方法研究了含有过量TiO_2的BaTiO_3粉末在不同温度下的物相关系,并对实验结果进行了分析和讨论。     

XRF分析铁矿粉的标准选择判据研究和应用

本文对ＸＲＦ法分析铁矿的基体校正元素进行了研究，并建立了标准选择判据，编制的计算软件可以自动地从大量标样中选择适合该样品分析的标准。该法可用于粉末压片制样的分析，方法快速，准确度和精密度均符合生产要求。     

系列新铌酸盐A6n+[Bxm+Nb12-x]Nb4O42的合成及粉晶X射线衍射分析

０IntroductionNiobateshavemanykindsofstructures．TheseareperovskitetypeABO３（KNbO３），tungstenbronzetypeANb２O６（Ba２NaNb５O１５），chainandlamellartypes犤１～１１犦．SincethenewcompoundK６CrNb１５O４２withakindoftunnelstructureinthepotassiumniobatesystemwasfoundinourlaboratoryforthefirsttime犤１２犦，wehavesynthesizedaseriesofcompoundswiththesamestructure，forexample，K６FeNb１５O４２，K６Ni０．６７Nb１５．３３O４２，Ba６Cr４Nb１２O４２andBa６Ni２．６７Nb１３．３３O４２etc．T…     

镍钛记忆合金的X射线荧光光谱法分析

制备了供试验室日常分析用的镍－钛合金标准样。不均匀性小于０．０５％,标准成分的设计含量可直接用作标准数据。采用人标法和样品优化的测量方式可使分析结果的相对标准偏并达０．０２％,与重量法分析结果对照结果相符。     

应用波长色散X荧光仪和多晶X射线衍射仪联用技术 鉴定进口铜矿和含铜物料

本文首次研究进口可利用含铜物料与进口铜矿属性的不同特性并建立鉴定方法,采用X荧光光谱法和X射线衍射光谱法联用技术建立铜矿和含铜物料属性的鉴别方法。通过X荧光光谱法对铜矿和含铜物料中元素进行定性半定量分析,再用X射线衍射光谱法对铜矿和含铜物料的特征谱峰进行扫描,与X衍射仪中标准卡片比对分析,能够确定铜矿和含铜物料的物相组成。结果显示：X荧光光谱法铜矿和含铜物料的共同特点铜的含量较高,达到冶炼铜对原料的要求,硅、铁、钠、钙和镁元素都能够检出。差异性在铅和锌元素在含铜物料中较高,在铜矿石中基本未检出;在X荧光光谱法检测出的金属元素,通过X衍射仪扫描后与标准图片比对,各元素以不同的形式存在于含铜物料中,且有规律可循。     

X射线衍射定量相分析新方法

在基体清洗法的基础上提出一种新的X射线衍射定量分析方法，该方法是利用混合样品X射线衍射谱图中的全部衍射峰数据，把清洗剂同样品中所包含的所有待测物相的纯相按比例混合，在同一水平下同时测定各物相与清洗剂对应的几个K值，结合JCPDS卡中的各相标准谱峰的相对强度分布数据进行最小二乘方程组的抛弃平均法回归分析，求得混合物样品中各相间的全谱峰匹配强度比，用于混合物样品的X射线衍射定量相分析，有利于提高定量相分析的精度，通过对四组分混合物样品的分析，实验结果和理论完全一致。     

面粉中滑石粉的X射线衍射分析

通过四氯化碳分离或高温灰化,X射线衍射分析测定面粉中掺入的滑石粉。其中灰化处理适宜温度为500~750℃。该方法简便、快速,灵敏度高,样品用量少,准确可靠,可推广为检测面粉质量的一种较理想的手段。     

L-5-羟基色氨酸粉晶晶体结构解析

以50%甲醇溶液为提取溶剂,从加纳籽中提取L-5-羟基色氨酸(HTP),采用RP-HPLC获得纯度为99.5%样品,经80%甲醇溶液重结晶获得多晶粉末.利用X射线粉末衍射技术结合计算晶体学方法解析其粉晶晶体结构,模拟图谱与实验图谱的Rwp值为5.06%.结果表明:该晶体属单斜晶系,P2_1空间群,晶胞参数为a=13.69927 ±0.01967(A),b=5.34550 ±0.00756(A),c=7.88219±0.01129(A),a=y=90.00000°,β=86.25936±0.00359°,Z=2,V=579.973(A)~3,并在此基础上对其晶体生长特性进行了分析.     

粉末压片-X射线荧光光谱法快速测定生石灰粉中氧化钙和二氧化硅

采用粉末压片法制样,建立了波长色散X射线荧光光谱法快速测定生石灰粉中氧化钙、二氧化硅的分析方法。由于没有国家标准样品,采用自制生石灰粉标准样品绘制工作曲线。考察了样品粒度及吸潮对分析结果的影响。实验表明,在样品粒度为74μm、压样机压力为12 MPa、压制时间为45s的制样条件下荧光计数率最稳定,在30min内测定样品效果最佳。采用α理论系数法和经验系数法相结合校正基体影响。对同一生石灰粉样品进行精密度实验,各组分的相对标准偏差(RSD,n=11)在0.04%~0.43%。测定了5个生石灰粉样品,所得结果与常规化学分析方法测定值相符。     

L-精氨酸·氟硼酸加合物的X射线粉末衍射分析

采用X射线粉末衍射法对L-精氨酸·氟硼酸加合物进行了分析.数据收集范围在2θ角从7°到80°(共64个观测点).采用最小二乘法对该加合物粉末衍射的晶胞参数进行了计算,实验表明:该加合物为正交晶系,空间群P212121,晶胞参数a=0.50702(6)nm,b=1.37288(12)nm,c=1.64880(15)nm,V=1.147713nm3;Z=4;ρ=1.52g/cm3,粉末衍射分析的结果与单晶结构数据相吻合.     

Synchrotron Radiation for Structural Chemistry—Endohedral Natures of Metallofullerenes Found by Synchrotron Radiation Powder Method

The recent progress of the structural studies of endohedral metallofullerenes by the synchrotron radiation (SR) powder diffraction utilizing the maximum entropy method (MEM) is reviewed. Results of the endohedral metallofullerenes (Y@C₈₂, La@C₈₂, Sc@C₈₂, Sc₂@C₈₄, Sc₃@C₈₂, Sc₂@C₆₆, La₂@C₈₀ and Sc₂C₂@C₈₄) are given. The precise MEM charge densities of metallofullerenes presents the direct image of endohedral nature of metallofullerenes indicating the charge transfer from metal atoms to carbon cage, which governs the stability of the unique endohedral structures. The MEM/Rietveld method and SR powder method using imaging plate (IP), which are the crucial methods for data analysis and measurement in order to determine structure of fulleride, are also mentioned in some detail.     

The Usefulness of X-ray Diffraction and Thermal Analysis to Study Dietary Supplements Containing Iron

X-ray powder diffraction (XRPD) and thermal analysis (differential scanning calorimetry/derivative of thermogravimetry (DSC/DTG)) are solid-state techniques that can be successfully used to identify and quantify various chemical compounds in polycrystalline mixtures, such as dietary supplements or drugs. In this work, 31 dietary supplements available on the Polish market that contain iron compounds, namely iron gluconate, fumarate, bisglycinate, citrate and pyrophosphate, were evaluated. The aim of the work was to identify iron compounds declared by the manufacturer as food supplements and to try to verify compliance with the manufacturer’s claims. Studies performed by X-ray and thermal analysis confirmed that crystalline iron compounds (iron (II) gluconate, iron (II) fumarate), declared by the manufacturers, were present in the investigated dietary supplements. Iron (II) bisglycinate proved to be semi-crystalline. However, depending on the composition of the formulation, it was possible to identify this compound in the tested supplements. For amorphous iron compounds (iron (III) citrate and iron (III) pyrophosphate), the diffraction pattern does not have characteristic diffraction lines. Food supplements containing crystalline iron compounds have a melting point close to the melting point of pure iron compounds. The presence of excipients was found to affect the shapes and positions of the endothermic peaks significantly. Widening of endothermic peaks and changes in their position were observed, as well as exothermic peaks indicating crystallization of amorphous compounds. Weight loss was determined for all dietary supplements tested. Analysis of the DTG curves showed that the thermal decomposition of most food supplements takes place in several steps. The results obtained by a combination of both simple, relatively fast and reliable XRPD and DSC/DTG methods are helpful in determining phase composition, pharmaceutical abnormalities or by detecting the presence of the correct polymorphic form.     

X-Ray Powder Diffraction Studies of Polyhydrates of Cross-Linked Tetraisoamylammonium Polyacrylates

X-ray powder diffraction studies were performed of the polyhydrates, formed at positive temperature in swelled grains of carboxylic cation-exchange resins in the form of tetraisoamylammonium (cross-linked tetraisoamylammonium polyacrylates, differing in the degree of cross-linking: 1, 2 and 3%). It was shown that the polyhydrates exist as the crystalline phase under specific conditions, determined earlier by DTA technique. Diffraction patterns of the samples, recorded at the temperature +3 ± 1 °C, indicate that the polyhydrates crystallize in hexagonal symmetry, the unit cell parameters are close to a=12.25 Å, c=12.72 Å and do not depend significantly upon the degree of cross-linking. The suppositions were made concerning the size of hydrate crystallites, formed in the swelled grains of the studied resins.This revised version was published online in July 2005 with a corrected issue number.