双波长分光光度法测定微量银的研究

本文用双波长分光光度法研究了Ag-5-Br-PADAP-柠檬酸-十二烷基硫酸钠多元显示体系。实验表明,该体系的显色适宜酸度为pH5.5,测量波长为532nm,参比波长为356nm。表观摩尔吸光系数为1.26×10~5l·mol~(-1)·cm~(-1),灵敏度比单波长提高近两倍。银量在0～20μg/25ml内符合比耳定律。方法简便快速,灵敏度高,适用于地质样品中微量银的测定。     

对称点群操作和对称操作变换矩阵

在结晶学和晶体结构测定中,由于计算上的某种需要,常常把原来的坐标系以原点为中心,按照某种方式转动某一角度而成为一种新坐标系。由于新、老坐标系有共同的原点,因此它们之间必然存在着某种内在上的联系,也就是说它们中的一种坐标系的某些量可以用另一个坐标的某些量的数学式来表示。坐标系变换后,结晶学中的一系列指数,如点群,晶面指数(hkl),晶棱方向指数[uvw],倒易点阵矢量等都会跟着变换。本文试图从数学出发,揭示这种变换关系,即变换矩阵。     

Cross polarization, magic-angle spinning C nuclear magnetic resonance spectroscopy of soil humic fractions

Cross polarization, magic-angle spinning ¹³C nuclear magnetic resonance spectroscopy was used to characterize humic fractions isolated from different soils. The acid fractions are more aromatic than the humin fractions, probably due to the higher polyssaccharide content of humins. However, fulvic acid fractions are more aromatic than the corresponding humic acid and humin fractions. These results can be interpreted in terms of the isolation procedure, because the high affinity of Polyclar AT for phenols results in higher aromaticities as compared with other isolation methods (e.g. charcoal).     

蒙山矿的晶体结构

本文对产于我国山东的新矿物蒙山矿(Mathiasite)进行了晶体结构精测。蒙山矿的晶体化学式为:(K、Ca、Sr)(Ti、cr、Fe、Mg、Zr)_(21)O_(38),三方晶系,空间群R,晶胞参数:a_o=10.3722,c_o=20.7161(六方定向),a_R=9.1403,a=69.187°(菱面体定向)。应用RASA-5RP自动转靶四圆单晶衍射仪,对蒙山矿收集了独立的1554个衍射强度。经结构解析和修正,求得了晶体中各原子的坐标、温度因子、占位度。并计算了原子的间距和键角。结构修正的偏离因子: R=0.047。蒙山矿产于金伯利岩中,形成于高温高压下。通过结构测定,确定了该矿物中Ti、Cr、Mg、K等元素的配位形式,特别是查明了Zr在这种以Ti为主的复杂氧化物中有独立的结晶学位置,并有缺席现象。以上研究成果丰富了金伯利岩中金属副矿物的矿物学和晶体化学内容。     

PC—1500A型微型计算机在金的光谱分析中的应用

本文阐明BASIC语言编写程序,将光谱分析法测定金所得的分析数据输入计算机,可由计算机打印出样品的分析线黑度、内标线黑度、金的含量等分析结果和数据,方法经实际应用,证明简便、快速,而且十分可靠。     

Analytical problems in determining peptide nitrogen in the humic fractions of three Italian soils

Peptides were released from organic matter fractions of three Italian soils (humin, humic and fulvic acids), when the samples were hydrolyzed in Ba(ON)₂-saturated solution at 105°C for 2 hr. The peptides obtained were separated using electrophoresis and paper chromatography. The presence of polypeptides in the soil organic matter was indicated by: (1) their hydrolysis by pronase; (2) the amino acids released by 6 N HCl hydrolysis; (3) The comparison of i.r. spectra of humic fractions before and after hydrolysis with 6 N HCl.Attempts at isolating the native proteinaceous compounds using electrophoresis in polyacrylamide gel failed; additionally, our attempts to hydrolyze proteinaceous components enzymatically in unfractionated soil organic matter, as well as in its fractions, before and after methylation, with pepsin, papain and pronase, were unsuccessful. Pronase demonstrated a weak proteolytic activity only at very low substrate-enzyme ratios (20 : 1) in humic and fulvic fractions and in whole phyrophosphate extract. Deproteinated substrates treated with pronase also released free amino acids, suggesting autodigestion.In humin, humic and fulvic fractions we found a total amino acid content of 40–45%, 12–24% or 1–85, respectively. Amino acid recovery from single fractions was about 70–80% of the total content in the unfractionated soil.     

Conceptual study — An improved method to assess acidification in German streams by using benthic macroinvertebrates

The present study is based mainly upon the authors' hydrochemical and hydrobiological studies of small silicate streams in South-West Germany, principally in the Black Forest and the Odenwald.

The aim of the paper is the adaptation of a practically proven four-level biological classification system of different degrees of acidity using benthic maroinvertebrates to a five-level system of acidification of mainly upland streams with low buffer capacity. The main reason for such a five-class system is the Water Framework Directive of the European Union (EU WFD), which lays down a five-level classification system for the assessment of the ecological quality of waters.

The biological method of assessing the state of acidity for evaluation of the degree of anthropogenic acidification under the directive, and principles of the EU WFD, are also described. A list of 278 taxa of the macrozoobenthos has been reclassified from a four-level system to a five-level biological indication system, based upon the authors' scientific expertise and the latest references from literature of different acid sensitive areas in Germany.     

多种跟踪组合卫星重力场恢复方法初探

将卫星地面跟踪、高低卫星跟踪和低低卫星跟踪恢复重力场的原理进行统一 ,导出了两种能充分综合多种跟踪观测的卫星重力场恢复基本观测方程。在建立基本观测量与重力场参数的函数传输关系的基础上 ,对目前存在的重力场恢复算法给出了直观的解释 ,并以距离二次变率为重力场恢复的基本观测量 ,提出了一种能组合各种卫星跟踪观测量的动态 /动力组合定轨和重力场恢复方法。     

镇江市地籍GPS控制网的检测及导线加密精度

对镇江市原有地籍GPS控制网的检测技术方案以及检测过程中的技术要求进行了介绍，并对在GPS控制网基础上加密的一、二级导线精度进行了估算。     

基于几何约束的GPS测姿系统的原理和实验

详细描述了GPS测姿系统的原理,并给出了一种基于基线长度约束和空间几何约束的最小二乘模糊度搜索算法,并经过静态和动态车载试验证明GPS测姿系统切实可行,在基线长度为3m的条件下,航向角精度优于0.1°。