测定痕量铝的新催化动力学指示反应研究

依据Ａｌ３ ＋ 催化Ｈ２Ｏ２ 氧化椪花青褪色的反应, 建立了测定痕量铝的催化动力学分析法． 线性范围为０ ～２００ｎｇ／ｍＬ , 检测限１－２ｎｇ／ｍＬ ． Ｆｅ３ ＋ 和Ｃｕ２ ＋ 的干扰分别用铜铁试剂－ 氯仿和双硫腙－ 四氯化碳溶液萃取除去, 而将Ｃｒ（ Ⅵ） 还原为Ｃｒ３ ＋ 即可消除其干扰．     

离子交换火焰原子吸收法测定水中Cr(Ⅲ)和Cr(Ⅵ)

研究了在ｐＨ＝２～３的条件下，用国产００１＃强酸性阳离子交换树脂、２０１×７＃强碱性阴离子交换树脂对水中Ｃｒ（Ⅲ）和Ｃｒ（Ⅵ）进行交换吸附，在Ｎａ２ＳＯ４存在下，用火焰原子吸收法直接测定交换后溶液中的Ｃｒ（Ⅵ）和Ｃｒ（Ⅲ）。方法简便易行，快速，特征质量为０．０７２μｇ／ｍＬ，相对标准偏差为２．７％，回收率为９５％～１０６％     

钼（Ⅵ）－硫酸肼－金莲橙Ⅳ体系催化动力学示波极谱法测定钼

利用酸性介质中钼（Ⅵ）对硫酸肼－金莲橙Ⅳ体系缓慢反应的催化作用，以氢氧化钠溶液中止反应，建立了一个动力学示波极谱测定钼的新方法。方法的线性范围为０．０１μｇ／ｍＬ～０．２μｇ／ｍＬ，已用于钢样中痕量钼的测定，结果满意。     

5''''-硝基-水杨基荧光酮-氯代十六烷基吡啶荧光熄灭法测定痕量Cr(Ⅵ)

基于Ｃｒ（Ⅵ）－５′－硝基－水杨基荧光酮（５′－Ｎ－ＳＡＦ）－氯代十六烷基吡啶（ＣＰＣ）体系的荧光熄灭效应，提出一种测定痕量铬（Ⅵ）的新荧光分析方法．ｐＨ在４．５～５．５范围内的柠檬酸—氢氧化钠缓冲溶液中，在ＣＰＣ存在下，Ｃｒ（Ⅵ）与５′－Ｎ－ＳＡＦ形成摩尔比为１２的配合物，配合物的激发波长和发射波长分别为：λｅｘ１＝４７５ｎｍ，λｅｘ２＝５０５ｎｍ，λｅｍ＝５２５ｎｍ．Ｃｒ（Ⅵ）浓度在０．８～５０μｇ／Ｌ范围内与ΔＦ呈良好的线性关系，相关系数ｒ＝０．９９９２，检测限为０．８μｇ／Ｌ．本法灵敏度高，选择性好，适用于水样、人发中痕量Ｃｒ（Ⅵ）的直接测定     

二溴硝基偶氮胂光度法测定水中的铬

研究了二溴氮肿与 Ｃｒ_２Ｏ_７~（２－）的褪色反应,发现其在硝酸介质中具有高灵敏的反应。Ｃｒ（Ⅵ）量在０～０ ２４μｇ２５ｍＬ内符合比耳定律,其摩尔吸光系数为 １． ５ ×１０~５。可用于水及废水中的铬的测定。     

新荧光试剂1－（3－甲氧基水杨醛缩氨基）－8－羟基－3，6－萘二磺酸钠荧光熄灭法测定痕量铬（Ⅵ）

本文用荧光熄灭法研究了１－（３－甲氧基水杨醛缩氨基）８－羟基－３，６－萘二磺酸钠（ＭＳＨＮＤ）－Ｃｒ（Ⅵ）体系的测定方法及条件。在ｐＨ＝４．００的邻苯二甲酸氢钾缓冲体系中，检测限为０．７ｎｇ／１０ｍＬ，线性范围为３．０～２０．０ｎｇ／１０ｍＬ。本法灵敏度高、选择性好，简单快速，用于测定地表水中痕量Ｃｒ（Ⅵ），结果满意。     

三氯偶氮氯膦光度法测定合金钢及水中的微量铬

目前利用褪色反应测铬的光度分析法大多灵敏度不高。通过研究三氯偶氮氯膦与Ｃｒ２Ｏ２－７的褪色反应,发现其在硝酸介质中具有高灵敏的褪色反应,其摩尔吸光系数ε＝１．１×１０５,是目前测铬的最灵敏的方法之一。研究发现该体系在５５０ｎｍ处具有最大吸光度ΔＡ,在硫酸、盐酸介质中加热３０ｍｉｎ时褪色不明显,在硝酸介质中加热１０ｍｉｎ已褪色完全。在ＨＮＯ３（Ｖ（ＨＮＯ３）∶Ｖ（Ｈ２Ｏ）＝１∶３）用量为３．０～５．５ｍＬ,０．５ｇ／Ｌ三氯偶氮氯膦溶液的用量为２．０～３．５ｍＬ,沸水浴加热８～１１ｍｉｎ时,褪色完全。本研究选取ＨＮＯ３４．５ｍＬ（Ｖ（ＨＮＯ３）∶Ｖ（Ｈ２Ｏ）＝１∶３）,三氯偶氮氯膦溶液２．５ｍＬ,沸水浴加热９ｍｉｎ。Ｃｒ（Ⅵ）质量浓度在０～０．４８μｇ／ｍＬ内符合比耳定律,回归方程为ΔＡ＝０．９７２５ρ（μｇ／ｍＬ）＋０．０１７３,相关系数γ＝０．９９６８。对１８种共存离子的干扰进行了测定,Ｆｅ２＋,Ｆｅ３＋,ＭｎＯ－４的干扰可在溶样时除去。用于合金钢及水中的微量铬的测定结果令人满意。     

N_2O—C_2H_2火焰原子吸收法测定土壤中痕量铍和钒

本文在文献［１］、［２］的基础上，进一步研究了用Ｎ＿２Ｏ—Ｃ＿２Ｈ＿２火焰原子吸收法测定土壤样品中痕量Ｂｅ和Ｖ时，样品的消解方法及消除共存组分干扰的方法，从而建立了Ｎ＿２Ｏ—Ｃ＿２Ｈ＿２火焰原子吸收法测定土壤样品中痕量Ｂｅ和Ｖ的方法。该法具有抗干扰能力强、准确可靠、简便易行、线性范围较宽的特点。测定Ｂｅ的线性范围为０—１μｇＢｅ／ｍＬ试液；测定Ｖ的线性范围为０—２５μｇＶ／ｍＬ试液。测定Ｂｅ和Ｖ的灵敏度（１％吸收）分别为０．０１４μｇ／ｍＬ和０．５１μｇ／ｍＬ，检测限分别为０．００７μｇ／ｍＬ和０．２５μｇ／ｍＬ。     

催化动力学光度法测定痕量钼

以罗丹明Ｂ为光度指示剂检测受钼（Ⅵ）催化的过氧化氢氧化碘离子的反应速度，建立了催化动力学法测定痕量钼的新方法．采用磺基水杨酸作催化反应的活化剂，提高了测定钼的灵敏度和选择性．该法测定钼的线性范围为０～０．０８μｇ／２５ｍＬ，测定下限（△Ａ＝０．０１）为１×１０－１０ｇ／ｍＬ．采用α－安息香肟氯仿溶液草取分离，测定了水样和尿样中钼．     

催化动力学光度法测定水中痕量铬（Ⅵ）

在弱酸性介质中，当有活化剂氨三乙酸存在时，铬（Ⅵ）对氯酸钾氧化罗丹明Ｂ褪色的反应具有强烈的催化作用。本文以此反应为指示反应，利用固定时间法研究了该催化反应的条件，建立了催化动力学光度法测定痕量铬（Ⅵ）的新方法。该方法的检出限为０．１５ｎｇＣｒ／ｍｌ，线性范围为０～２０ｎｇＣｒ／ｍｌ．将本方法用于水中痕量铬（Ⅵ）的测定，结果令人满意．     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

Perspherical Approaches for Electrons in Atoms and Charged Excitons in Quantum Wells

Instead of following Fock’s expansion,we solve the Schrodinger equation for some quantum mechanical manybody systems such as electrons in atoms and charged excitons in quantum wells in a similar way in hyperspherical coordinates by expanding the wave functions into orthonormal complete basis sets of the hyperspherical hannonics(HHs)of hyperangles and generalized Laguerre polynomials(GLPs)of the hyperradius.This leads the equation to     

Advances in broadband wireless communications under high-mobility scenarios

Future mobile communication systems aim at providing very high data transmission rates, even in high-mobility scenarios such as high-speed wheel-track trains, maglev trains, highway vehicles, airplanes, guided missiles or spacecraft. A particularly important commercial application is the strong and increasing worldwide demand for high- speed broadband wireless communications （up to 574.8 km/ h test speeds or 380 km/h commercial speeds） in railways, providing data, voice and video services for applications such as onboard entertainment services to passengers, train control, train dispatch, train sensor status handling and sur- veillance. In such high-mobility scenarios, there are a number of communication challenges, including fast hand- over, location updating, high-speed channel modeling, estimation and equalization, anti-Doppler spreading tech- niques, fast power control, and dedicated network architec- ture. Because signal transmission in very high-speed scenarios will inevitably experience serious deterioration, it is imperative to develop key broadband mobile communi- cation techniques for such high-speed vehicles.     

Wuhan University Journal of Natural Sciences TOTAL CONTENTS

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Scale-based spatial data model for GIS

Being the primary media of geographical information and the elementary objects manipulated, almost all of maps adopt the layer-based model to represent geographic information in the existent GIS. However, it is difficult to extend the map represented in layer-based model. Furthermore, in Web-Based GIS, It is slow to transmit the spatial data for map viewing. In this paper, for solving the questions above, we have proposed a new method for representing the spatial data. That is scale-based model. In this model we represent maps in three levels: scale-view, block, and spatial object, and organize the maps in a set of map layers, named Scale-View, which associates some given scales.Lastly, a prototype Web-Based GIS using the proposed spatial data representation is described briefly.     

英文诗歌中的喻类修辞

为了有助于提高英文爱好者的个人情操、文化素养和学习兴趣,以及专业人员对英语学习和研究进行多途径的探索,本文通过一些精选诗歌的引证和分析,着重论述了喻类修辞法在英文诗歌中的运用其及效果。     

Man Is Unable to Change the Miserable Life——Analysis of the Arrangement of Four Characters in The Glass Menagerie

Tennessee Williams is considered as one of the most important American playwrights since World War II.The Glass Menagerie is his first successful drama,which describes a tragic situation of family and means to say that Man is unable to change the miserable life,no matter whatever means he try,This essay focuses on the analysis of the arrangement of the four main characters:Laura.Amanda,Jim and Tom to reveal the theme.Laura is fragile.Amanda is brave.Jim is vital.Tom is sensible.And all of them develop and try the different means to struggle against life,but fail tragically.With the evidence,the paper comes to conclusion naturally that Man is unable to change the miserable life,and he dooms to fail.     

Characterization of root-nodulating bacteria on Retama raetam in arid Tunisian soils

The aim of this study is to investigate the diversity of Retama raetam root-nodule bacteria isolated from arid regions of Tunisia. Twelve isolates, chosen as representative for different 16S rRNA gene patterns, were characterized by 16S rRNA gene sequencing and phenotypic analysis. Isolates were assigned to Sinorhizobium, Rhizobium and Agrobacterium. Symbiotic properties of Sinorhizobium and Rhizobium isolates showed a large diversity in their capacity to infect their host plant and fix atmospheric nitrogen. Strain RK 22 identified as Rhizobium was the most effective isolate.     

An Affordable Accurate Evaluation of the Binding Conformations Predicted by Molecular Docking Studies in Bio-System

正Recently,docking has been widely used to predict the binding-modes of protein-inhibitors,when the crystal complexes structure was absent.Most docking algorithms are able to generate a large number of probable conformations,it,however,is difficult to effectively evaluate these docking poses and identify the most reasonable bindingmode.In the present study,on the basis of the crystallographic data of human 3-hydroxy-3-methylglutaryl coenzyme     

WIMAX与WI-FI技术分析及联合组网

介绍了WiMAX与Wi-Fi两种无线宽带接入技术,并对两者之间的关系及相互之间的影响做了对比及分析,并对WiMAX的关键技术进行了详细说明,最后对两者的联合组网方式做了简单的探讨。