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1.
以瓯江彩鲤为试验材料,采用联合指数相加法,研究了铜和阿特拉津对瓯江彩鲤的急性毒性和联合毒性效应.实验结果表明:Cu2+的毒性大于阿特拉津毒性;Cu2+对瓯江彩鲤24、48、72和96 h的LC50分别为0.74、0.40、0.34和0.29 mg·L-1,阿特拉津对瓯江彩鲤24、48、72和96 h的LC50分别为68.16、52.14、48.33和42.37 mg·L-1.联合毒性实验结果表明,24、48、72、96 h的相加指数分别为2.17、1.35、1.59、2.08,Cu2+和阿特拉津共存时对瓯江彩鲤的毒性为协同作用.  相似文献   

2.
Cu~(2 )、Zn~(2 )对老年低额溞的联合毒性试验   总被引:2,自引:0,他引:2  
在研究了 Cu2+和 Zn2+分别对老年低额溞Simocephalus vetulus Straus 96 h急性毒性反应的基础上,采用相加指数法进行了联合毒性试验。结果表明: Cu2+对老 年低额溞24、 48、 72、 96 h LC50分别为 0.83、 0.71、 0.61、 0.55 mg/L; Zn2+对 老年低额溞24、 48、 72、 96 h LC50分别为 0.89、 0.54、 0.42、 0.30 mg/L。 Cu2 +和 Zn2+对老年低额溞的安全浓度( Sc)分别是 0.0055 mg/L和 0.0030 mg/ L。当 C u 2+与 Zn2+共存时其联合毒性发生拮抗作用。  相似文献   

3.
通过单因子静态急性毒性试验法和等毒性溶液法分别研究了重金属离子铜、锌对汤匙华哲水蚤的急性毒性和联合毒性效应.急性毒性试验结果表明:铜、锌离子对汤匙华哲水蚤24 h半致死浓度(LC50)分别为0.481、3.221 mg/L;48h LC50分别为0.383、1.573 mg/L;72h LC50分别为0.315、0.471 mg/L.铜、锌联合毒性致毒特征表明:高强度的锌离子对铜离子有拮抗作用,高强度的铜离子对锌离子有协同作用.  相似文献   

4.
铜、锌离子对汤匙华哲水蚤的急性毒性和联合毒性效应   总被引:1,自引:0,他引:1  
通过单因子静态急性毒性试验法和等毒性溶液法分别研究了重金属离子铜、锌对汤匙华哲水蚤的急性毒性和联合毒性效应.急性毒性试验结果表明:铜、锌离子对汤匙华哲水蚤24 h半致死浓度(LC50)分别为0.481、3.221 mg/L;48h LC50分别为0.383、1.573 mg/L;72h LC50分别为0.315、0.471 mg/L.铜、锌联合毒性致毒特征表明:高强度的锌离子对铜离子有拮抗作用,高强度的铜离子对锌离子有协同作用.  相似文献   

5.
4种重金属离子对黑鲷幼鱼的急性毒性研究   总被引:1,自引:0,他引:1  
以体长(5.09±0.71)cm、体质量(2.09±0.66)g的黑鲷幼鱼为实验动物,采用静水停食试验法,在水温(28.8±1.6)℃,pH 8.24条件下,开展了Zn2+、Cr6+、Cu2+、Hg2+4种重金属离子对黑鲷幼鱼的急性毒性试验。结果表明,Zn2+对黑鲷幼鱼的24h、48 h、72 h、96 h LC50分别为11.53 mg/L、10.15 mg/L、6.56 mg/L、6.09 mg/L;Cr6+对黑鲷幼鱼的24 h、48 h、72 h、96 h LC50分别为31.48 mg/L、24.31 mg/L、23.01 mg/L、23.01 mg/L;Cu2+对黑鲷幼鱼的24 h、48 h、72 h、96 h LC50分别为2.75 mg/L、1.55 mg/L、1.30 mg/L、1.06 mg/L;Hg2+对黑鲷幼鱼的24 h、48 h、72 h、96 h LC50分别为0.098 8 mg/L、0.098 1 mg/L、0.089 2 mg/L,0.0742 mg/L。4种重金属离子对黑鲷幼鱼的毒性强度由高到低依次为Hg2+、Cu2+、Zn2+、Cr6+。最后还就重金属离子对黑鲷幼鱼的致毒特征、对黑鲷幼鱼早期发育的影响,以及水环境中重金属离子的毒性评价与控制进行了探讨。  相似文献   

6.
Cu2+和Cr6+对中国林蛙蝌蚪的急性毒性   总被引:2,自引:1,他引:2  
采用中国林蛙(Rana chensinensis)出膜后一周的蝌蚪为实验对象,研究了Cu2 和Cr6 对中国林蛙蝌蚪的急性毒性.实验结果表明,在水温22℃~24℃条件下,Cu2 对中国林蛙蝌蚪24 h,48 h,72 h的半致死浓度(LC50)分别为0.131,0.105,0.038 mg/ L;Cu2 对蝌蚪的安全浓度为0.02 mg/ L.Cr6 对中国林蛙蝌蚪24 h,48 h,72 h的半致死浓度(LC50)分别为4.16,4.48,4.57 mg/ L;Cr6 对蝌蚪的安全浓度为1.55 mg/ L.同时讨论了中国林蛙与其他两栖类蝌蚪相比对Cu2 和Cr6 耐受性的差异.  相似文献   

7.
铅、镉污染对水丝蚓的急性毒性效应   总被引:5,自引:0,他引:5  
本实验以霍甫水丝蚓(Limnodrilus hoffmeisteri Claparede)为对象,采用静水生物测试法研究了铅、镉单一及复合污染对水丝蚓的急性毒性效应.单一实验结果表明,铅和镉对水丝蚓作用24h的LC50分别为:7.096mg/L,31.621mg/L,作用48h的LC50分别为4.731mg/L,23.441mg/L.复合试验结果表明,铅和镉复合污染24h对水丝蚓的急性毒性具有明显的协同作用,复合污染48h时,低浓度的铅与镉具有协同作用,高浓度的铅与镉具有拮抗作用.  相似文献   

8.
在研究了Cu^2 和Zn^2 分别对老年低额NaoSimocephalus vetulus Straus96h急性毒性反应的基础上,采用相加指数法进行了联合毒性试验,结果表明:Cu^2 对老年低额Nao24、48、72、96hLC50分别为0.83、0.71、0.61、0.55mg/L;Zn^2 对老年低额Nao24、48、72、96hLC50分别为0.89、0.54、0.42、0.30nm/L.Cu^2 和Zn^2 在老年低额Nao的安全浓度(Sc)分别是0.0055mg/L和0.0030mg/L.当Cu^2 与Zn^2 共存时其联合毒性发生拮抗作用。  相似文献   

9.
在研究了Cu2+和Zn2+分别对老年低额磣(Simocephalus vetulus Straus)96h急性毒性反应的基础上,采用相加指数法进行了联合毒性试验。结果表明Cu2+对老年低额磣24、48、72、96hLC50分别为0.83、0.71、0.61、0.55mg/L;Zn2+对老年低额磣24、48、72、96hLC50分别为0.89、0.54、0.42、0.30mg/L。Cu2+和Zn2+对老年低额磣的安全浓度(Sc)分别是0.0055mg/L和0.0030mg/L。当Cu2+与Zn2+共存时其联合毒性发生拮抗作用。  相似文献   

10.
采用标准水生生物毒性的测量方法研究三氯杀螨醇对黑斑蛙蝌蚪的急性毒性效应,结果表明,在15~20℃下,三氯杀螨醇对黑斑蛙蝌蚪的24 h、48 h和72 h的半数致死浓度(LC50)分别为17.861、3.82和8.21 mg/L,95%可信区间分别是15.37~20.751,2.62~15.147,.81~8.63 mg/L。安全浓度(SC)为2.49 mg/L。  相似文献   

11.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

12.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

13.
本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。  相似文献   

14.
Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with  相似文献   

15.
The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to  相似文献   

16.
17.
The explosive growth of the Internet and database applications has driven database to be more scalable and available, and able to support on-line scaling without interrupting service. To support more client's queries without downtime and degrading the response time, more nodes have to be scaled up while the database is running. This paper presents the overview of scalable and available database that satisfies the above characteristics. And we propose a novel on-line scaling method. Our method improves the existing on-line scaling method for fast response time and higher throughputs. Our proposed method reduces unnecessary network use, i.e. , we decrease the number of data copy by reusing the backup data. Also, our on-line scaling operation can be processed parallel by selecting adequate nodes as new node. Our performance study shows that our method results in significant reduction in data copy time.  相似文献   

18.
R-Tree is a good structure for spatial searching. But in this indexing structure,either the sequence of nodes in the same level or sequence of traveling these nodes when queries are made is random. Since the possibility that the object appears in different MBR which have the same parents node is different, if we make the subnode who has the most possibility be traveled first, the time cost will be decreased in most of the cases. In some case, the possibility of a point belong to a rectangle will shows direct proportion with the size of the rectangle. But this conclusion is based on an assumption that the objects are symmetrically distributing in the area and this assumption is not always coming into existence. Now we found a more direct parameter to scale the possibility and made a little change on the structure of R-tree, to increase the possibility of founding the satisfying answer in the front sub trees. We names this structure probability based arranged R-tree (PBAR-tree).  相似文献   

19.
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.  相似文献   

20.
The geographic information service is enabled by the advancements in general Web service technology and the focused efforts of the OGC in defining XML-based Web GIS service. Based on these models, this paper addresses the issue of services chaining,the process of combining or pipelining results from several interoperable GIS Web Services to create a customized solution. This paper presents a mediated chaining architecture in which a specific service takes responsibility for performing the process that describes a service chain. We designed the Spatial Information Process Language (SIPL) for dynamic modeling and describing the service chain, also a prototype of the Spatial Information Process Execution Engine (SIPEE) is implemented for executing processes written in SIPL. Discussion of measures to improve the functionality and performance of such system will be included.  相似文献   

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