首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 546 毫秒
1.
研究了哌嗪甲萘醌亚硫酸盐(MPB)和三氨基三嗪甲萘醌亚硫酸盐(MTB)对海水小球藻的抑制作用以及对发光细菌毒性试验分析.结果表明:MPB和MTB对小球藻具有良好的抑制效果而且对环境友好.MPB和MTB在72 h时的半效应质量浓度(EC50)分别为4.28 mg.L-1和6.61 mg.L-1.MPB和MTB对海水小球藻的抑制随着质量浓度和作用时间增加而加强,当达到一定的质量浓度时,MPB和MTB的抑制效果达到饱和.10 mg.L-1以下的MPB和MTB的发光细菌抑光率远远低于30.  相似文献   

2.
通过半静态染毒法研究了啶虫脒的急性毒性.在此基础上,进一步研究了半静态和静态两种染毒方式下不同质量浓度(ρ=0.001,0.005,0.009,0.013,0.017 mg·L-1)的啶虫脒溶液对中华蟾蜍(Bufo gargarizans)蝌蚪血红细胞微核及核异常的诱导作用.结果表明,啶虫脒对中华蟾蜍蝌蚪的24,48,72,96h的ρLC50分别为0.544,0.095,0.058,0.036 mg·L-1.在低于安全质量浓度(0.003 6 mg·L-1)下处理7 d,蝌蚪的微核率与核异常率与对照组相比均无统计学差异.半静态实验表明,随着啶虫脒质量浓度的提高及染毒时间的延长,蝌蚪的微核率及核异常率呈不断上升的趋势;在质量浓度为0.005 mg·L-1的啶虫脒溶液中处理3 d后,蝌蚪的微核率和核异常率开始比对照组有显著和极显著提高.静态实验中,在质量浓度为0.005 mg·L-1的啶虫脒溶液中处理3 d后,蝌蚪的微核率出现有显著的提高;各处理组核异常率的最高值出现在染毒3~5 d后,而后出现下降现象,但仍高于对照组.说明由于时间的延长,药性的衰退,蝌蚪能通过机体的调整而得到部分修复.上述实验结果说明,微核率及核异常率的提高可能是评价啶虫脒应用安全的潜在灵敏指标.  相似文献   

3.
为了评价伊维菌素对斑腿泛树蛙蝌蚪遗传毒性的影响,采用碱性单细胞凝胶电泳的方法 (SCGE)检测在不同质量浓度伊维菌素溶液(0.000 5,0.004 0,0.007 5,0.011 0,0.014 5 mg·L-1)中处理48 h和96 h后斑腿泛树蛙蝌蚪血红细胞DNA的损伤情况.结果表明,在实验室条件下,随着伊维菌素质量浓度的增加和染毒时间的延长,蝌蚪血红细胞的DNA损伤率和DNA的总体损伤程度随之增加.在质量浓度为0.000 5 mg·L-1的伊维菌素溶液中处理48 h后,蝌蚪血红细胞的DNA损伤率出现极显著的提高;当伊维菌素的质量浓度达到0.007 5 mg·L-1时,蝌蚪血红细胞的DNA损伤率和DNA总体损伤程度均出现极显著的提高;在同一处理时间内,伊维菌素质量浓度与DNA总体损伤程度之间存在剂量效应关系.研究表明,伊维菌素对两栖动物蝌蚪具有一定的遗传毒性作用,存在着影响水生态平衡的风险.  相似文献   

4.
在实验室条件下,通过单因子实验和正交实验,研究了不同氮(N)、磷(P)、铁(Fe)和硅(Si)的营养盐及其质量浓度对直链藻生长速率的影响.氮元素的营养盐为:硫酸铵(NH4)2SO4、硝酸钠(NaNO3)和尿素(NH2)2CO,氮质量浓度分别为0,10,20,30,40,50,60 mg·L-1;磷元素的营养盐为:磷酸二氢钾(KH2PO4)和磷酸二氢钠(NaH2PO4),磷质量浓度分别为0,0.5,1,2,3,4,5 mg·L-1;铁元素的营养盐为:硫酸亚铁(FeSO4)和柠檬酸铁(FeC6H5O7),铁质量浓度分别为0,0.02,0.05,0.1,0.2,0.3,0.4,0.5 mg·L-1;硅元素的营养盐为:硅酸钠(Na2SiO3),硅质量浓度分别为0,5,10,15,20,25,30,35,40 mg·L-1.单因子的实验结果表明:对直链藻生长速率(K值)影响最大的营养元素分别为:N,P,Fe,Si,其对应的最佳营养盐质量浓度范围分别为20~40 mg·L-1;0.5~1 mg·L-1;0.02~0.05 mg·L-1;10~20 mg·L-1.正交实验结果表明:培养直链藻的最佳营养盐[(NH2)2CO,KH2PO4,FeC6H5O7,Na2SiO3]质量浓度配比为30∶0.5∶0.05∶10.  相似文献   

5.
以黑眶蟾蜍蝌蚪及中华大蟾蜍蝌蚪为研究对象,采用微核实验检测了甲氨基阿维菌素苯甲酸盐(甲维盐)对2种蝌蚪红细胞的微核及核异常的诱导.结果表明:在实验室条件下,当质量浓度达到0.02mg.L-1的甲维盐处理24h,黑眶蟾蜍蝌蚪红细胞的微核率和核异常率与对照组相比有极显著的提高;当质量浓度达到0.01mg.L-1的甲维盐处理48h,中华大蟾蜍蝌蚪红细胞的微核率和核异常率与对照组相比有极显著的提高;在一定质量浓度和时间范围内,蝌蚪红细胞微核率和核异常率随甲维盐质量浓度的增加和染毒时间延长而增加,并显示出两者之间存在一定的剂量效应关系.甲维盐对2种蝌蚪的红细胞造成显著的遗传损伤.  相似文献   

6.
用壳聚糖脱除废水中的铜离子   总被引:11,自引:0,他引:11  
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.  相似文献   

7.
采用内电解预处理,研究组合工艺上流式厌氧污泥床(UASB)-A/O2下污染物转化降解特性.结果表明:最佳工况条件下,当进水化学需氧量(COD)和酚质量浓度分别为2 500 mg·L-1和320.0 mg·L-1时,最终出水COD低于150mg·L-1,酚质量浓度小于0.1 mg· L-1.气质联仪(GCMS)分析表明:内电解预处理可降解杂环化合物、降低废水的毒性,有利于后续生化处理;UASB能有效地将焦化废水中的多支链酚类转化为结构相对简单的酚类,对喹啉类化合物有较高的去除率;经过缺氧和接触氧化处理后,出水有机物种类大量减少.  相似文献   

8.
采用缺氧/厌氧-生物膜技术,结合活性炭过滤、紫外线氯消毒的组合工艺深度处理居民区生活污水,分别以冲洗厕所和景观用水为目标,考察再生水的水质状况和主要参数;对比研究以混合生活污水和灰水分别作为中水源的技术和经济适用性.中试研究结果表明,以居住区生活污水(化粪池出水)作为中水源,运行条件停留时间8h、污泥质量浓度3500~7500 mg·L-1、出水无色无味,化学需氧量质量浓度低于30 mg·L-1,五日生化需氧量质量浓度低于3 mg·L-1,氨氮质量浓度低于3.0mg· L-1,可以稳定达到杂用水标准,但总氮、总磷浓度无法满足景观用水要求;模拟原污水(化粪池进水)的污染物浓度比例,运行条件为停留时间10h、污泥龄50 d、回流比为200%、污泥质量浓度5500~6000mg·L-1、外加聚合铝(有效铝)4~5 mg·L-1时,再生水的水质均优于冲厕和景观用水标准.在达到相同的再生水水质条件下,居住区的生活污水混合收集处理比灰水单独收集处理的工艺流程复杂,处理费用比后者高0.32元·m-3.居民区污水资源化采用何种收集和再生方式不仅要考虑技术经济合理性,还需结合居民区再生水的用途和用水量、当地气候条件等因素综合确定.  相似文献   

9.
采用线性极化电阻技术和交流阻抗技术研究了锅炉水冷管材在过氧化氢溶液钝化条件下的电化学特征,结合SEM电子扫描技术对不同钝化条件下的钝化膜成膜形貌进行观察测量. 实验结果表明,在柠檬酸漂洗后采用过氧化氢钝化的过程中,当过氧化氢的质量分数为0.1%,溶液pH为9.5,亚铁离子的质量浓度为100 mg·L-1且氯离子的质量浓度低于50 mg·L-1时钝化效果最好,钝化膜成膜形貌较为完整,管材抵抗外界腐蚀的能力最强.  相似文献   

10.
植物生长调节剂对欧李离体培养的影响   总被引:2,自引:0,他引:2  
以MS为基本培养基,附加不同质量浓度的细胞分裂素BA(6-卞基腺嘌呤)、KT(激动素)和生长素NAA(萘乙酸)、IBA(吲哚丁酸),进行欧李萌芽、成芽、幼芽增殖及生根(1/2MS),形成完整的植株,从中筛选其最适宜的培养基。幼芽诱导时,以单独使用质量浓度为2.0 mg.L-1的BA最好,诱导率为100%;但混合使用时,以MS BA 1.0 mg.L-1 NAA 0.3 mg.L-1效果最好,诱导率也为100%。欧李幼芽增殖时,则以MS BA 1.0 mg.L-1 NAA 0.1 mg.L-1效果最好,增殖系数为8.19。生根时,以1/2MS IBA 1.0 mg.L-1最好,其生根率为91.7%。移栽时,根长度约1.2 cm为适宜,移栽基质以蛭石为最好。  相似文献   

11.
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   

12.
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   

13.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

14.
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  相似文献   

15.
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.  相似文献   

16.
17.
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   

18.
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.  相似文献   

19.
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   

20.
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   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号