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 268 毫秒
1.
Se(Ⅳ)对钝顶和极大螺旋藻生长的影响   总被引:1,自引:0,他引:1  
采用藻类生长动力学函数和藻类测试化学品毒性的标准方法,分别研究了高、低质量浓度Se(Ⅳ)对钝顶(S.platensis)和极大(S.maxima)螺旋藻生长的影响,结果表明:低质量浓度组中,Se(Ⅳ)的质量浓度低于16mg/L时对钝顶螺旋藻前4d的生长影响差异无显著性意义,但当质量浓度为32mg/L时出现明显的抑制作用;而低质量浓度范围内,即质量浓度低于32mg/L的Se(Ⅳ)在前4d对极大螺旋藻的生长的影响不明显.高质量浓度组中,当质量浓度高于560mg/L时,钝顶螺旋藻的生长被完全抑制;硒对极大螺旋藻的最低完全抑制质量浓度为600mg/L.  相似文献   

2.
以草本植物肾蕨、麦冬和头花蓼的幼苗为材料,分别与香樟幼苗组合配植并进行Cd胁迫(0.1, 0.3, 1, 5 mg/L)溶液培养(CK:香樟单种), 4周后测定香樟幼苗生物量、幼苗和培养液Cd质量浓度,研究地被植物对香樟生长和富集Cd的影响.结果表明,香樟—肾蕨(CN)、香樟—麦冬(CO)组合可显著增加香樟生物量.当Cd的质量浓度为5.0 mg/L时,香樟全株生物量比CK分别提高46.77%和42.47%; CN组合能显著提高香樟Cd富集量.当Cd的质量浓度为0.1 mg/L时,其地上部分和全株富集量分别为(1.639±0.133)μg/株和(7.351±0.575)μg/株,比CK分别提高137.88%和77.86%; CN、香樟—头花蓼(CP)组合可显著提高香樟对Cd的转运能力.当Cd的质量浓度为5.0 mg/L时,其转移系数分别为0.161和0.138,比CK分别提高76.92%和106.41%; CO组合能显著提高培养液Cd去除率.当Cd质量浓度为0.1 mg/L时, Cd去除率达68.67%,比CK提高50.01%.结果显示,香樟与地被植物肾蕨、麦冬和头花蓼配植可显著促进其生长和对Cd的吸收转运.其中,香樟与肾蕨配植积极影响最全面,与麦冬配植Cd去除率最高.  相似文献   

3.
为了从有毒植物中发现新的农药活性化合物进行植物源农药的研究与开发,采用浸叶法测定了6种有毒植物乙醇提取物对蚜虫的触杀活性,结果表明臭灵丹乙醇提取物在2000 mg/L、5000 mg/L和10000 mg/L浓度时,对蚜虫的校正死亡率分别为76.83%、92.85%和100%;采用浸虫浸草法测定了6种有毒植物乙醇提取物对东亚飞蝗的触杀活性,结果表明臭灵丹乙醇提取物在10000 mg/L、作用120 h时,对东亚飞蝗的校正死亡率达到72.00%;采用活性跟踪法对臭灵丹杀蝗虫活性成分进行分离、纯化,最终得到活性较好的化合物1,在1000 mg/L、作用72 h时,对东亚飞蝗的校正死亡率为67.86%,为进一步研究臭灵丹的杀虫活性成分提供了一定理论研究基础.  相似文献   

4.
两种抗生素对褶皱臂尾轮虫种群增长的影响   总被引:1,自引:0,他引:1  
采用种群累积培养法,研究了两种抗生素,即氯霉素(Chloromycetin)和烟酸氟哌酸(Nicotinic Norfloxacinum)对褶皱臂尾轮虫(Brachionus plicatilis)种群增长的影响.结果表明,不同剂量的氯霉素对轮虫种群的增长有明显的影响(P<0.01),浓度为0.012 5 mg/mL时可促进种群增长,当浓度增加到0.025 0~0.050 0 mg/mL时,则有不同程度的抑制作用,0.050 0 mg/mL的浓度抑制作用明显;不同剂量的烟酸氟哌酸对轮虫种群的增长亦有明显的影响(P<0.01),低剂量组(0.250 0和0.500 0 mg/mL)可促进种群增长,而高剂量组(0.75和1.00 mg/mL)则为抑制作用.  相似文献   

5.
吡虫啉(Imidacloprid)是一种新烟碱类杀虫剂,但其对轮虫等水生无脊椎动物的毒性尚无从知晓.本文以萼花臂尾轮虫(Brachionus calyciflorus)为受试生物,应用种群增长、休眠卵产量和生命表实验等方法,研究了不同浓度的吡虫啉(0、1.56、3.12、6.25、12.5、25、50和100 mg/L)对其种群增长和生命表统计学等参数的影响.结果表明,吡虫啉浓度对轮虫存活(以生命期望为指标)、发育(世代时间)、生殖(净生殖率)和种群增长(内禀增长率和种群增长率)等参数均有显著性影响(P<0.01),但对有性生殖(后代混交率、种群混交率和休眠卵产量)等参数都无显著性影响(P>0.05).与对照组相比,12.5 mg/L吡虫啉处理组中轮虫种群增长率显著升高(P<0.05),而50和100 mg/L吡虫啉处理组中轮虫种群增长率则显著降低(P<0.05).3.12~12.5 mg/L吡虫啉处理组中轮虫的生命期望显著延长(P<0.05),而25~100 mg/L吡虫啉处理组中轮虫的生命期望则显著缩短(P<0.01).1.56~12.5 mg/L吡虫啉处理组中轮虫的世代时间显著延长(P<0.05),净生殖率显著升高(P<0.01),而50~100 mg/L吡虫啉处理组中轮虫的世代时间显著缩短(P<0.01),25~100 mg/L吡虫啉处理组中轮虫的净生殖率显著降低(P<0.01).50~100 mg/L吡虫啉处理组中种群内禀增长率显著降低(P<0.05).吡虫啉浓度与轮虫存活、发育、生殖和种群增长等参数之间均具有显著的剂量-效应关系.在监测吡虫啉的慢性毒性时,净生殖率是较敏感的指标.  相似文献   

6.
为了得到γ-亚麻酸(GLA)高产菌株,以深黄被孢霉As3.3410为出发菌株,利用氮离子(N+)注入诱变,并采用马来酰肼抗性筛选和红四氮唑(TTC)法相结合对突变株进行筛选。试验结果表明:当能量为10 ke V时,最佳氮离子诱变剂量为1.56×1015cm-2;当马来酰肼的添加量为40 mg/L时,出发菌株的抑制率为100%;TTC法酶活测定的最佳条件为:温度35℃、p H为8.4、TTC浓度为8 g/L、反应时间为1 h,以此作为摇瓶初筛的条件。经过反复诱变筛选获得一株遗传稳定的高产突变株F312,其γ-亚麻酸产量为1 236 mg/L,比出发菌株(480 mg/L)提高了157.5%。  相似文献   

7.
对低剂量臭氧在剩余活性污泥减量中的应用进行了探讨.结果表明,当活性污泥进行低剂量臭氧(≤0.010 mgO3/mgMLSS)处理时,可取得较好的减量化效果.当臭氧投加剂量为0.010 mgO3/mgMLSS时,反应60 min活性污泥的总去除率达到77.73%.臭氧处理会同时导致溶解性化学需氧量(SCOD)的增加.臭氧投加剂量为0.005 mgO3/mgMLSS时污泥中的SCOD增加至20.28 mg/gMLSS·L.污泥沉降比(SV%)减少率随臭氧投加剂量的增大呈线性增加趋势.低剂量处理后的污泥容积指数(SVI)值在58~62 mg/L之间,污泥的沉降性能良好,并未产生污泥膨胀现象.  相似文献   

8.
谷氨酸钠对钝顶螺旋藻生长及色素的影响   总被引:2,自引:0,他引:2  
在Zarrouk培养液中添加不同质量浓度的谷氨酸钠,研究其对钝顶螺旋藻生长和色素质量比的影响。结果表明,低质量浓度的谷氨酸钠能促进螺旋藻的生长,提高螺旋藻中叶绿素a、类胡萝卜素和藻蓝蛋白的质量比,而当谷氨酸钠质量浓度超过1g/L后,钝顶螺旋藻的生长和色素质量比都受到明显抑制,藻蓝蛋白也受到破坏。  相似文献   

9.
以高脂饲料造型高血脂大鼠 ,饲喂不同剂量的螺旋藻饲料 ,建立血清甘油三酯值(TG)随时间 (t)变化的函数 ,通过求解其降脂极限临界值 ,推算出使高血脂大鼠达到健康标准的剂量组区间为 4 5 0mg/kg≤TG≤ 810mg/kg ,相应的理论服用期为 13.6周≤t≤ 195 5周 ;利用求得的理论值与对应的剂量建立量效函数关系 ,精确求解出最低有效剂量临界值为 377.4mg/kg .并应用该函数模型对螺旋藻降血脂量效与时效的互逆运算进行了探讨  相似文献   

10.
壳聚糖复合絮絮凝剂处理印染废水,正交实验结果分析表明:当pH=6时,壳聚糖用量4mg/L,聚合氯化铝用量为200mg/L,先100r/min搅拌1min时,投入聚合氯化铝和壳聚糖后再300r/min搅拌2min,最后以50r/min搅拌10min,浊度去除率均达90%以上,COD去除率达50%以上。对浊度和COD去除率的影响因素主次顺序是:聚合氯化铝投加量〉pH〉壳聚糖投加量〉搅拌时间。  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  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.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

15.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

16.
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   

17.
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   

18.
19.
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   

20.
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   

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