一种适合常规分析的氨氮测定方法

采用预蒸馏纳氏试剂吸光光度法测定污水中的氨氮,以Ｈ３ＢＯ３ 溶液作吸收剂时,有色胶体的稳定性较差,加入ＮａＯＨ溶液可提高胶体的稳定性。当ＮａＯＨ 溶液（１ ｍｏｌ／Ｌ）与Ｈ３ＢＯ３ 溶液（２ ％） 的体积相同时,有色胶体稳定时间最长。加入胶体保护剂聚乙烯醇（ＰＶＡ） 可进一步提高胶体的稳定性和测定准确度。对Ｈ３ＢＯ３ ,ＮａＯＨ 和ＰＶＡ 的影响规律进行了研究,提出了最佳实验条件：以２％ Ｈ３ＢＯ３ 溶液作吸收液,１ ｍｏｌ／ＬＮａＯＨ 溶液１０ ｍＬ,罗谢尔盐溶液１．００ ｍＬ,５％ 聚乙烯醇０．１６ ｍＬ,纳氏试剂１ ．００ ｍＬ,反应１０ ｍｉｎ。该方法的最低检出限为０．０１５ ｍｇ／Ｌ,回收率为９８ ．６％ ～１０３％ ,适用于环保站、化工厂进行的常规分析     

土壤中有效磷的快速测定

用ｃ（ＮＨ４Ｆ）＝０．０１５ｍｏｌ／Ｌ的ＮＨ４Ｆ和ｃ（ＨＣｌ）＝０．３ｍｏｌ／Ｌ的ＬＣｌ提土壤样品中有效磷,以钼锑抗分光光度法测定有效磷的含量。在ｃ（Ｈ２ＳＯ４）＝０．２～０．３ｍｏｌ／Ｌ的Ｈ２ＳＯ４和Ｓｂ＾３＋存在下,到与钼酸铵反应形成磷锑钼杂多酸,该杂多酸在常温下被抗坏血酸还原为磷钼蓝络合物,它的最大吸收波长于７００ｎｍ处,磷量在０．１～１４００μｇ／Ｌ内服从比尔定律,检出限为０．０２４μｇ／     

聚铝处理低浓度SO_2烟气的研究

研究了以聚合硫酸铝为吸收剂处理低浓度ＳＯ２烟气的工艺条件,通过吸收和解吸,达到富集ＳＯ２的目的．考察了聚合硫酸铝浓度、盐基度、吸收温度以及解吸温度等因素对吸收和解吸过程的影响．结果表明,聚合硫酸铝溶液对ＳＯ２具有较高吸收率和解吸率,并可多次循环使用．     

Cl~- 和 SO_4~(2-) 对厌氧废水处理的抑制阈值

用人工配制高浓度有机废水分别研究了Ｃｌ－和ＳＯ２－４对厌氧生物废水处理的抑制作用和抑制阈值．在全混流厌氧恒化器和上流式厌氧污泥床（ＵＡＳＢ）反应器中分别得到了对厌氧消化基本无抑制作用（全混流恒化器：Ｃｌ－＜４．５ｇ／Ｌ,ＳＯ２－４＜１．８ｇ／Ｌ;ＵＡＳＢ：Ｃｌ－＜７．２ｇ／Ｌ,ＳＯ２－４＜３．０ｇ／Ｌ）;轻度抑制（全混流恒化器：Ｃｌ－＝４．５～６．０ｇ／Ｌ,ＳＯ２－４＝１．８～３．３ｇ／Ｌ;ＵＡＳＢ：Ｃｌ－＝７．２～８．２ｇ／Ｌ,ＳＯ２－４＝３．０～４．１ｇ／Ｌ）;中度抑制（全混流恒化器：Ｃｌ－＝６．０～１３．８ｇ／Ｌ,ＳＯ２－４＝３．３～６．５ｇ／Ｌ;ＵＡＳＢ：Ｃｌ－＝８．２～１０．０ｇ／Ｌ,ＳＯ２－４＝４．１～６．０ｇ／Ｌ）和重度抑制（全混流恒化器：Ｃｌ－＞１３．８ｇ／Ｌ,ＳＯ２－４＞６．５ｇ／Ｌ;ＵＡＳＢ：Ｃｌ－＞１０．０ｇ／Ｌ,ＳＯ２－４＞６．０ｇ／Ｌ）的不同Ｃｌ－和ＳＯ２－４浓度范围．     

氢氧化钠水溶液吸收羰基硫反应级数研究

常压下温度为３０～５０℃，用鼓泡反应器测定了羰基硫（ＣＯＳ）在浓度为１．３１３０～４．４０３８ｋｍｏｌ／ｍ３ＮａＯＨ水溶液中的吸收速率，通过理论分析得到该吸收为一级不可逆快反应吸收过程。     

球茎甘蓝鲜、干重变化及需肥规律的研究

研究了球茎产量在６０５８８．２ｋｇ／ｈｍ２条件下,球茎甘蓝植株鲜重、干重的增长动态及Ｎ,Ｐ,Ｋ,Ｓ的吸收规律。结果表明：植株鲜重、干重在出苗后７６～９０ｄ生长最快;平均每生产１０００ｋｇ球茎植株需吸收Ｎ３．２８ｋｇ,Ｐ２Ｏ５１．９４ｋｇ,Ｋ２Ｏ３．１７ｋｇ,Ｓ１．０６ｋｇ（比例为１．００∶０．５９∶０．９７∶０．３２）;植株吸收的Ｎ,Ｐ２Ｏ５,Ｋ２Ｏ主要贮存在球茎内,Ｓ则主要贮存在叶内;植株对Ｎ的吸收高峰在出苗后６１～７５ｄ,对Ｐ２Ｏ５,Ｋ２Ｏ和Ｓ的吸收高峰均在出苗后７６～９０ｄ。     

温度对Cr2O7^2—阳极形成过程的影响

用分解极化曲线法研究了在０．１ｍｏｌ／ＬＣｒ２（ＳＯ４）３＋１ｍｏｌ／ＬＮａ２ＳＯ４溶液中Ｐｔ和ＰｂＯ２电极上Ｃｒ２Ｏ７＾２－阳极形成和Ｏ２析出过程中温度的影响。实验结果表明,在１．９５Ｖ下,Ｐｔ电极上Ｏ２和Ｃｒ２Ｏ７＾２－的表观活化能分别为５７．４ｋｊ／ｍｏｌ和６１．３ｋｊ／ｍｏｌ;ＰｂＯ２电极上Ｏ２和Ｃｒ２Ｏ７＾２－表观活化能分别为４０．２ｋｊ／ｍｏｌ和４６．２ｋｊ／ｍｏｌ。温度对于Ｃｒ２Ｏ７     

鸡蛋水解产物对酸性,碱性溶液中碳钢阳极过程的影响

通过测定碳钢在含有不同浓度鸡蛋水解产物的２ｍｏｌ／Ｌ盐酸、２ｍｏｌ／Ｌ硫酸、２ｍｏｌ／Ｌ碳酸铵溶液中的阳极极化曲线，研究了碳钢在不同介质中的阳极过程，发现鸡蛋水解产物对在酸性、碱性溶液中的碳钢皆有明显的缓蚀作用．在ＨＣｌ溶液及（ＮＨ４）２ＣＯ３溶液中，鸡蛋水解产物的最佳浓度为２．０％，在Ｈ２ＳＯ４溶液中，鸡蛋水解产物的最佳浓度为１．０％，并对鸡蛋水解产物的缓蚀性能进行了理论探讨     

Na2SeO3对稻苗生长及谷胱甘肽过氧化物酶的影响

以水稻为材料根施系列浓度的Ｎａ２ＳｅＯ３，试验对稻苗生长以及对苗中ＧＳＨＰｘ的影响．结果表明，低浓度的Ｎａ２ＳｅＯ３（００５～１０ｍｇ／Ｌ）能促进稻苗生长，最适浓度为０５ｍｇ／Ｌ；高浓度（≥２０ｍｇ／Ｌ）则对稻苗产生毒害．稻苗ＧＳＨＰｘ活性高度依赖于Ｓｅ的存在，揭示出该酶可能是一种依赖于Ｎａ２ＳｅＯ３的诱导酶．ＧＳＨＰｘ能有效地抵抗稻苗的Ｓｅ中度中毒，其酶活较对照提高９５８％；对于严重Ｓｅ中毒的稻苗有一定的抵抗作用，其酶活较对照提高６９２％．     

荧光素荧光法测定大气中SO2的研究

报道了以荧光素为指示剂,荧光法间接测定大气中ＳＯ２ 的方法．在ｐＨ＝ ５．５ ～７ ．５ 中性缓冲介质中,Ｉ２ 与荧光素反应,使荧光素的荧光熄灭,当加入ＳＯ２－３ 时,ＳＯ２－３ 与Ｉ２ 反应使体系荧光增强,体系激发波长、发射波长分别为４９４ ｎｍ 和５１０ｎｍ ,ＳＯ２－３ 含量在２ ．１～６０．０ μｇ／Ｌ范围内呈良好线性关系,检测下限为２．１ μｇ／Ｌ．     

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.     

Wuhan University Journal of Natural Sciences TOTAL CONTENTS

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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.     

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     

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。