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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:3,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.
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 Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.  相似文献   

13.
王慧 《科技信息》2008,(10):240-240
Wuthering Heights, Emily Bronte's only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.  相似文献   

14.
何延凌 《科技信息》2008,(4):258-258
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.  相似文献   

15.
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   

16.
Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.  相似文献   

17.
以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.  相似文献   

18.
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   

19.
Quality traits in wheat (Triticum aestirum L.) were studied by quantitative trait locus (QTL) analysis in a recombinant inbred line (RIL) population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross (ChSh). Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.  相似文献   

20.
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   

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