缬氨霉素铷离子选择电极的制备和应用

缬氨霉素为中性载体的PVC膜铷离子选择电极有较好的选择性,KpRotb,K=0.35。该电极已用于铷的分析测定和含Rb+的水和醇水体系的热力学性质的研究。     

等离子体发射光谱法同时测定岩石中微量锆、铪、铌和钽等元素

本文介绍了一种快速离子交换分离—ICP-AES法同时测定岩石中微量锆、铪、铌和钽等元素的新方法。样品经碱熔、浸取、过滤,其沉淀连同滤纸放回原烧杯,加入H~+型阳离子交换树脂和少量酒石酸溶液。基体元素(Fe~(3+),Al~(3+),Ca~(2+),Mg~(2+)等)被树脂吸附,锆、铪、铌和钽与酒石酸形成稳定络合物存留在溶液中,经干过滤后,用ICP-AES方法直接测定。欲测元素的样品分析实际检出限分别为:Zr0.2ppm。Hf、Nb、Ta均为0.4ppm。实践证明,本方法不仅步骤简单,分析速度快,而且分析结果或靠,精密度和准确度良好。     

蒸馏分离-苯芴酮比色法测定煤中锗

介绍蒸馏分离-苯芴酮比色法测定煤中锗的含量,对测量过程中的影响因素进行分析,提出解决办法。     

西藏尼玛一带上白垩统竟柱山组的厘定及其意义

西藏尼玛县城西-色林错一带发育一套山间河湖相的红色碎屑岩系,属红色磨拉石建造。该红色碎屑岩系底部不整合于下白垩统及其以下层位之上。其时代归属尚不统一,有划归为上三叠统巫嘎群,有划归为古近系始新统牛堡组。2000～2002年作者在尼玛县城西、双湖区南措折乡宋我日分别测制了剖面,2002年又在尼玛县城西剖面补采样品,获得丰富的孢粉化石。根据所含孢粉组合特征及时代,将其划归上白垩统竟柱山组。     

Disproportionation of Fe<Superscript>2+</Superscript> in Al-free silicate perovskite in the laser heated diamond anvil cell as recorded by electron probe microanalysis of oxygen

Experimental evidence is reported for Fe²⁺ disproportionation in Al-free perovskite (Pv), when submitted to large temperature gradients (i.e., under off-equilibrium conditions) in a laser heated diamond anvil cell (LHDAC). To enable this effect, the experimental procedure was designed to produce large radial and axial temperature gradients. In the Pv and ferropericlase (Fp) assemblage synthesized after dissociation of natural olivine, the three chemical states of iron (i.e., Fe⁰, Fe²⁺ and Fe³⁺) could be evidenced by electron probe microanalysis (EPMA), through variations of oxygen contents attached to the Fe cations. Despite inherent difficulties for determination of O-contents and Fe³⁺/ΣFe ratios using EPMA, we recorded significant changes in iron oxidation state across the laser-heated strip. These changes are correlated with variations in composition for the major elements (Fe, Mg, and Si), which evidences that the Pv/Fp assemblage experienced large segregation under the strong temperature gradients. Grains of metallic iron were detected in parts of the laser-heated strip coexisting with a Pv phase with Fe/(Mg + Fe) = 6 at% and most of its iron as Fe³⁺. This Fe²⁺-disproportionation reaction involves insertion of Fe³⁺-defects in the Pv lattice. This Fe³⁺-bearing Pv phase is presumably unstable and decomposes into a mineral assemblage including magnesioferrite, which is detected at the border of the laser-heated strip.     

利用非组合精密单点定位技术确定斜向电离层总电子含量和站星差分码偏差

联合双频GPS数据,利用相位平滑伪距算法,可得到包含斜向电离层总电子含量（slant total electron content,sTEC）、测站和卫星差分码偏差（differential code bias,DCB）的电离层观测值（称之为＂平滑伪距电离层观测值＂）,常应用于与电离层有关的研究。然而,平滑伪距电离层观测值易受平滑弧段长度和与测站有关的误差影响。提出一种新算法：利用非组合精密单点定位技术（precise point positioning,PPP）计算电离层观测值（称之为＂PPP电离层观测值＂）,进而估计sTEC和站星DCB。基于短基线试验,先用一台接收机按上述两种方法估计sTEC,用于改正另一接收机观测值的电离层延迟以实施单频PPP,结果表明,利用PPP电离层观测值得到的sTEC精度较高,定位结果的可靠性较强。随后,选取全球分布的8个IGS（internationalGNSS service）连续跟踪站2009年1月内某四天的观测数据,利用上述两种电离层观测值计算所有卫星的DCB,并将计算结果与CODE发布的月平均值进行比较,其中,平滑伪距电离层观测值的卫星DCB估值与CODE（Centre for Orbit Deter mination in Europe）发布值的差别较大,部分卫星甚至可达0.2～0.3 ns,而PPP电离层观测值而言,绝大多数卫星对应的差异均在0.1 ns以内。     

西藏塔惹增地区上白垩统竟柱山组的厘定及其意义

分布于塔惹增地区帕荣山一带的一套碎屑岩夹碳酸盐岩,对其时代归属缺乏可靠的古生物化石,一直颇有争议.前人根据岩性将其归为古近系日贡拉组,通过对此套地层详细的剖面研究表明其时代为上白垩统竟柱山组,其沉积环境为残留海相沉积,此套地层的时代厘定,为研究怒江洋在该地区的关闭提供了重要的基础地质资料.     

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云南绿春洒马中泥盆世早期龙别组地层时代厘订

根据新发现的竹节石化石Nowakia maureri cf.latemaureri Alberti,确定龙别组时代为中泥盆世早期埃姆斯期.其硅质岩浊流沉积特征为海槽环境成生.     

SHORT COMMUNICATION A PROGRAM FOR THE SIMULTANEOUS POTENTIOMETRIC DETERMINATION OF PROTONATION CONSTANTS AND ELECTRODE CALIBRATION PARAMETERS

A program for the potentiometric determination of the protonation constants of mononuclear polyproticsubstances is described.A maximum of twelve parameters can be determined simultaneously,includingup to six protonation constants,four electrode calibration parameters,the protolysis constant of thesolvent and the titrant concentration.Optimization is carried out by using the non-simplifiedNewton-Raphson method,which is potentiated by the Marquardt algorithm and a distance speeding-upcoefficient.A direct search method is also used to improve the initial set of values.Variances arecalculated very accurately,since the real Hessian function is used.Statistical weights and ionic strengthcorrections are also considered,The program has been tested by using simulated titration curves ofpolyprotic acids with close constants.