壳聚糖絮凝剂处理废水中的Ag~+

研究了利用壳聚糖絮凝剂絮凝除Ag的方法.考察了pH值、离子溶液浓度、絮凝剂用量以及絮凝时间对去除率的影响.实验结果表明:壳聚糖絮凝除银的适宜pH为7~8;当pH=7~8时,用壳聚糖吸附银离子,水样银质量浓度低于20 mg/L时,除银率达100%.即使高浓度含银水样,其除银率也在99.9%以上;絮凝除银时间4 h为宜,其去除率达99.98%;壳聚糖的加入量过多过少都会影响除银效果.分析了壳聚糖絮凝除银的机理.     

膨润土负载壳聚糖处理含镉废水的实验研究

以脱乙酰度为90%壳聚糖为原料,制备膨润土负载壳聚糖复合吸附剂,用于吸附含镉废水溶液中的Cd2+.探讨壳聚糖负载量、pH值、吸附时间、吸附剂加入量、Cd2+初始质量浓度对去除率的影响.结果表明,对于初始质量浓度为10mg/L的含镉模拟废水溶液,在膨润土与壳聚糖质量比为1∶0.03,加入量为8g/L,pH=6,吸附时间为50min的条件下,Cd2+的去除率在94%以上.该吸附剂经再生处理后可循环使用4次.     

用壳聚糖脱除废水中的铜离子

研究了利用脱乙酰基壳聚糖絮凝剂絮凝除铜的方法.考察了氢氧化物、pH值、铜离子质量浓度、絮凝时间以及絮凝温度对去除率的影响.当pH=8时,用壳聚糖吸附铜离子,水样铜离子质量浓度低于100 mg.L-1时,除铜率在99%以上;即使铜离子原始质量浓度在400 mg.L-1,残液铜离子质量浓度仍符合国家废水排放标准.用NaOH絮凝沉淀,pH=11时,除铜率达100%,耗碱量大,不符合废水排放的酸度要求.     

壳聚糖对活性染料红M-3BE的絮凝脱色效果

从壳聚糖的质量浓度、pH值、温度、处理方式、常用染色助剂(元明粉和纯碱)等因素入手研究了壳聚糖对活性红M-3BE的絮凝脱色性能.结果表明:在100 mL染料溶液(100 mg/L)中,加入10 mL壳聚糖醋酸溶液(0.4g/L),壳聚糖对染料的絮凝脱色效果随染液pH值的下降而增加明显,脱色率在90%以上;但随常用染色助剂(元明粉和纯碱)浓度的增加,其絮凝脱色效果显著下降.在较佳絮凝条件下,壳聚糖对该染料染色废水的脱色率和COD去除率分别为19.84%和54.81%.此外,用壳聚糖处理活性染料染色废水时,需先用酸中和染色残液中的碱剂,再进行脱盐处理,以便壳聚糖发挥更好的絮凝脱色作用.     

环境友好产品--过氧化钙的合成及其应用

通过加入新型稳定剂磷酸铵,研究了常温水相中合成过氧化钙的新工艺.讨论了原料配比、浓度、温度、时间、稳定剂加入量等因素对过氧化钙产率和纯度的影响,在最佳条件下合成的CaO2纯度大于65%.采用CaO2产品处理含铜、镉、铅、锌离子的工业废水,通过原子吸收分光光度计测定处理前后废水中铜、镉、铅、锌离子的浓度.结果表明,在室温下,过氧化钙用量与重金属离子摩尔比为2∶1时,处理60 min,处理过程不调节pH的条件下,含铜54.12 mg/L、镉36.58 mg/L、铅22.74 mg/L、锌30.10 mg/L的废水经一次处理后,铜、镉、铅、锌去除率均达到99.5%以上,且铜、镉、铅、锌浓度均达到国家一级水排放标准.     

两性淀粉絮凝剂对染料废水的絮凝性能研究

以两性淀粉为絮凝剂处理染料废水,并与复配聚合氯化铝絮凝剂、木质素基改性絮凝剂、壳聚糖季铵盐絮凝剂和聚丙烯酰胺絮凝剂的絮凝性能进行比较,研究废水的pH、絮凝剂的质量浓度对其絮凝性能的影响。结果表明,两性淀粉絮凝性能优于上述絮凝剂;并且在pH为6.0～8.0、絮凝剂两性淀粉絮凝剂的质量浓度为65mg/L时,废水的COD去除率最高可达50%。     

γ辐射法制备壳聚糖接枝共聚物及其絮凝性能

以壳聚糖(Cts)和甲基丙烯酸(MAA)为原料,应用γ射线辐射引发技术进行接枝共聚反应,制备了壳聚糖与甲基丙烯酸的接枝共聚产物(Cts-g-MAA),采用搅拌实验和测浊度法研究接枝改性壳聚糖对铅锌选矿废水的絮凝效果,其中考察了废水pH值、Cts-g-MAA的质量浓度、快速搅拌速度、慢速搅拌时间、静置时间对絮凝效果的影响,并将其与壳聚糖的絮凝能力进行了对比.实验结果表明,废水的pH值、絮凝剂质量浓度、搅拌速度、搅拌时间和静置时间均对絮凝效果产生影响,其最佳絮凝条件为pH值8.5、Cts-g-MAA浓度1.2mg/L、搅拌强度300 r/min、慢速搅拌时间为10 min、静置时间为11 min,此条件下的浊度去除率达98.6%.接枝改性壳聚糖的絮凝效果好于壳聚糖,且絮凝时的用量明显低于壳聚糖.     

壳聚糖与生物絮凝剂复配协同增效絮凝特性研究

为了提高絮凝剂的絮凝性能以提升养殖污水的处理效率，利用壳聚糖具有的絮凝特性，并依据壳聚糖与絮凝剂之间的共聚反应，设计了5种不同浓度组合基质的处理，分析了絮凝剂投加量、生物絮凝剂与壳聚糖复配比例、pH等对COD去除率的影响.结果表明：在投加量为30.0 mg/L,pH=5,生物絮凝剂与壳聚糖复配比(V/V)为21∶9时，对养殖污水COD的去除率最高.壳聚糖与生物絮凝剂复配获得的复合絮凝剂对COD,NH₃—N,BOD,SS及TP污水指标的去除率分别达到85.2%,81.0%,85.0%,58.3%和27.5%.     

絮凝菌处理页岩气压裂返排液的响应面优化

采用实验室已经筛选出的具有絮凝活性的菌株,考察发酵培养时间对絮凝效果的影响,并进行絮凝性能测定。测定结果表明,菌株H5为Acinetobacter baumannii strain,发酵培养36 h时,其絮凝率可达到65.7%。采用絮凝菌与PAC复配的方法处理页岩气压裂返排液,并且应用响应面分析法对处理过程进行了优化。设定响应值为COD去除率,根据响应值的分布情况确定最佳絮凝条件为：絮凝菌H5的投加量10 mg/L;PAC浓度30 mg/L;慢速搅拌速度73 r/min;沉降时间40 min。最佳絮凝条件下,联合处理对压裂返排液中COD去除率为85.1%,浊度去除率95%以上。     

内电解-芬顿氧化-絮凝组合工艺处理硝基苯废水

硝基苯作为一种典型硝基芳香族化合物（NACs）,其对人类健康和生态环境具有极大的危害,因此探究硝基苯的高效降解方法具有重要意义。采用内电解-芬顿氧化-絮凝组合工艺处理硝基苯废水,探究镀铜率、反应时间、曝气量、pH及n(H2O2)/n(Fe2+)等参数对该组合工艺处理废水效果的影响,完成相关工艺参数条件优化,并揭示相关耦合机理。实验结果表明：在镀铜率为0.5%、曝气量为0.5 L/h、反应时间为6 h的条件下,初始质量浓度为50 mg/L的硝基苯可被铁铜内电解转化成苯胺,转化率为99.8% (±0.2%);芬顿氧化反应在n(H2O2)∶n(Fe2+)=10∶1、pH=3.0、ρ(Fe2+) = 60 mg/L的条件下,苯胺的去除率达到99.8% (± 0.3%);絮凝沉淀反应中阴离子PAM的絮凝效果更好,当加入2 mL质量浓度为10 mg/L的阴离子PAM时,废水的色度为20倍,达到了国家规定的一级排放标准。综上所述,该组合工艺在处理含硝基苯废水中具有较好的可行性,可为实现大规模化处理含高浓度NACs废水奠定基础。     

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

<正>~~     

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。