铅和锌混合液在菲律宾蛤仔体内的积累及其致毒效应

研究了铅,锌对菲律宾蛤仔的急性毒性,以及铅,锌混合液在菲律宾蛤仔体内的积累和对过氧化氢酶酶活性的影响。结果表明：铅的毒性略大于锌的毒性：铅、锌混合液对蛤仔体内的重金属吸收存在交互作用。     

菲律宾蛤仔黏附污泥絮凝机制研究

菲律宾蛤仔粘附污泥作为天然絮凝剂具有良好的天然絮凝活性,为研究其絮凝活性产生机制,本文针对粘附污泥中的生物因素(细菌、真菌、无菌蛤仔)和非生物因素(泥沙)等生态组成,建立5组蛤仔暂养系统,分别投加细菌双抗生素、真菌双抗生素、细菌双抗生素和真菌双抗生素联用、不加栖息地泥沙、以及正常暂养对照(加栖息地泥沙),比较各生态因素对菲律宾蛤仔所产粘附污泥的絮凝沉淀性能的影响。结果表明,细菌是菲律宾蛤仔粘附污泥具备絮凝性能的关键生物因素,栖息地泥沙是促进粘附污泥絮凝的重要非生物因素;耐药絮凝活性细菌使得细菌双抗生素组的粘附污泥仍具备一定的絮凝活性;多糖是菲律宾蛤仔粘附污泥产生絮凝作用的重要物质基础。     

福州市沿海养殖双壳类动物重金属研究

本文对福州市沿海养殖区的双壳类体内铅、镉、铜、锌含量加以比较研究。河口附近养殖的缢蛏体内铅和镉含量,比养殖于近海或内湾的高。内湾养殖的菲律宾蛤仔体内铜含量,比养殖于近海区的高。铅对贻贝、缢蛏、菲律宾蛤仔、长牡蛎的污染达到轻度或中度,这表明铅是福州市沿海养殖双壳类动物的重要污染因子。根据指数分析,五种双壳类受重金属综合污染程度顺序为:菲律宾蛤仔>缢蛏>褶牡蛎>长牡蛎>贻贝,但四种重金属含量均未超标。铅和铜的含量高低与养殖方式有关,趋向于吊养种类体内铅和铜含量较低,而埕养种类的铅含量和条石养殖种类的铜含量较高。     

天津汉沽鲤鱼门潮间带的经济贝类资源

2013年10月对天津汉沽鲤鱼门潮间带的经济贝类资源进行调查.结果发现:该区域经济贝类有9科10种,主要经济贝类有菲律宾蛤仔、四角蛤蜊、微黄镰玉螺和纵肋织纹螺,其中菲律宾蛤仔为优势种,占经济贝类资源总量的91.6%,平均栖息密度为263.7粒/m2,平均生物量为916.4 g/m2.蛤仔群体结构方面,壳长小于20 mm的蛤仔数量占总数的7.7%,壳长在20~30 mm之间的蛤仔占53.1%,总商品率为39.2%.同2008年9月的调查结果相比,2013年的贝类种类及生物量增加,多样性指数降低,蛤仔大量出现,这与近年来邻近海域的大规模增殖放流活动密切相关.     

维生素D_3对菲律宾蛤仔三种抗氧化酶活性的影响

以维生素D3 不同浓度0 IU/L、5000 IU/ L、10000 IU/ L、15000 IU/ L、20000 IU/ L浸浴菲律宾蛤仔96h,观测维生素D3对菲律宾蛤仔内脏团过氧化氢酶(CAT)、超氧化物歧化酶(SOD)和谷胱甘肽过氧化物酶(GSH-Px)活性的影响. 结果表明,经维生素D3浸浴菲律宾蛤仔内脏团中的CAT、SOD活性随时间延长均表现为先升高后降低趋势,比较同一时间段10000 IU/L组CAT、SOD活性均高于其他浓度组(p<0.05);而在试验过程中GSH-Px活性随时间延长有一直升高的趋势,但比较同一时间段15000 IU/L组活性均高于其他浓度组(p<0.05). 本研究表明利用维生素D3微粒悬浮于水层中被蛤仔滤食,可一定程度提高菲律宾蛤仔抗氧化活性,其剂量以10000 IU/L 到15000 IU/L范围内效果较好.     

菲律宾蛤仔养殖水体中4种重金属安全限量的研究

双壳贝类富集重金属会给消费者食用安全造成危害。本文以菲律宾蛤仔Ruditapes philippinarum为研究对象,采用生物富集双箱动力学模型测定双壳贝类对4种重金属Hg、Pb、Cd和As的生物富集动力学参数。结果表明:贝类对重金属的生物富集和排出都较缓慢,经过30 d生物富集未达到稳态平衡,Hg、Pb、Cd的生物富集系数BCF分别为1 030、935和378,生物半衰期处在18～33 d范围内,As的生物富集和排出无明显规律性。参考欧盟和我国菲律宾蛤仔标准中关于Hg、Pb、Cd的安全限量,通过BCF计算得到菲律宾蛤仔养殖水体中Hg、Pb、Cd的安全限量分别为0.0005mg/L,0.01 mg/L和0.026mg/L。     

四种滤食性贝类滤食器官鳃的扫描电镜观察

利用扫描电子显微镜技术对海湾扇贝、栉孔扇贝、太平洋牡蛎、菲律宾蛤仔４种滤食性养殖贝类的滤食器官的形态结构进行了观察和比较。结果表明：１、４种贝类的鳃纤毛是极其发达的,鳃丝内侧分布大量的粘液细胞;２、海湾扇贝、栉孔扇贝鳃丝的侧纤毛不如太平洋牡蛎和菲律宾蛤仔的发达,太平洋牡蛎鳃丝内侧纤毛很发达;３、４种贝类鳃线之间的距离都大于２０μ,鳃丝间距排序为菲律宾蛤仔〈海湾扇贝〈栉孔扇贝〈太平洋牡蛎。从电镜观察     

菲律宾蛤仔氮、磷代谢的初步研究

在室内实验条件下研究了温度、壳长及投喂不同藻类对菲律宾蛤的氮磷排泄率的影响,实验的温度范围为８～１７℃,贝类的壳长为２９．１～５２．７ｍｍ,所有的测定均在停喂２４小时后进行．实验结果显示,菲律宾蛤仔的排氨率和排磷率与壳长呈负相关关系,而与温度呈正相关关系,壳长与氮磷排泄率的关系都符合如下模式：Ｙ＝ａＬｂ,并且随时间的推移其氮磷排泄率有下降的趋势．摄食不同单胞藻对菲律宾蛤仔氮磷排泄率影响不大．黑暗条件下菲律宾蛤仔的排氨率明显高于光照条件下,而排磷率的变动很大且不规律     

菲律宾蛤仔酶解液脱腥工艺研究

以菲律宾蛤仔为原材料,选用胰蛋白酶对菲律宾蛤仔进行酶解,采用粉末活性炭联合安琪高活性干酵母脱腥,最佳脱腥条件为先添加1.5%的安琪高活性干酵母,30℃发酵反应1 h,离心过滤后再用粉末活性炭脱腥,其添加量为1.0%,温度30℃,时间30 min,pH 4,脱腥液中游离ANN含量为2.878 mg/g,损失率为7.9%,基本上没有腥味,含有酵母所特有的香味,脱腥液颜色比较澄清。     

菲律宾蛤仔黏附污泥用于废水处理的生物絮凝剂特性研究

菲律宾蛤仔黏附污泥已被报道为一种新型的天然生物絮凝剂,适合淡水处理和海水处理。本文探究了菲律宾蛤仔黏附污泥在实际废水处理中的应用效果。结果表明:菲律宾蛤仔黏附污泥作为絮凝剂可以有效去除废水中悬浮物(SS),去除率可达49.3%,并能有效改善膨胀的活性污泥的沉降性能,促进光合细菌的挂膜,促进率为33.3%;另外,其还有效吸附去除水中的重金属,当重金属离子Cd~(2+)、Zn~(2+)、Cu~(2+)的浓度分别为5.09 mg/L、14.09 mg/L、255.81 mg/L时,去除率分别达72%、67%、92%。     

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.     

Features of Women''s language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

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