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1.
研究了铅对原子吸收光谱法测定锑及铜的干扰及其消除方法,提出了测定铅钙合金中锑、铜的新方法.测定锑的特征浓度为0.4mg/L(1%),线性浓度范围0~30mg/L;测定铜的特征浓度为0.037mg/L(1%),线性浓度范围为0~3mg/L;方法简便快速,选择性好,经标样分析表明,结果的准确度及精密度均符合要求.  相似文献   

2.
红豆杉细胞植板方法的研究   总被引:3,自引:0,他引:3  
在红豆杉细胞植板中、适宜的培养基是优化的MS培养基,其中NAA浓度为0.5mg/L,6BA浓度为0.5mg/L,培养细胞生长周期为40d;培养在中最优碳源浓度是:蔗糖30g/L,葡萄糖10g/L,无机盐最佳浓度是:NH^+410mmol/L,NL^-340mmol/L,PO^3-41.25mmol/L。研究表明,培养基的pH值与植板率在。氨基酸及维生素等有机成分能明显促进细胞生长。  相似文献   

3.
参照瑞典制订的欧洲国家标准法的鱼类胚胎-鱼苗毒性测定技术,进行了农乳2201及吐温-80两种常用乳化剂对大鳞副泥鳅胚胎-鱼苗阶段毒性实验。结果表明,鱼苗比鱼卵对这两种乳化剂更敏感。农乳2201对鱼苗的最低影响浓度(LOEC)为0.14mg/L,最高无影响浓度(NOEC)为0.07mg/L,而吐温-80则分别为50、25mg/L.与由经验公式推算的结果相比较,差别比较大。尽管在鱼类毒性试验中通常要求溶剂及乳化剂不得超过0.1mg/L,但这个浓度对农乳2201来说仍有亚慢性效应。此外,由于浓度的吐温-80对饥饿状态的鱼苗有延长存活时间作用,故在使用欧洲国家标准法进行试验时,不适合使用这种乳化剂.  相似文献   

4.
在红豆杉细胞植板中,适宜的培养基是优化的MS培养基,其中NAA浓度为0.5mg/L,6BA浓度为0.5mg/L;培养细胞生长周期约40d;培养基中最优碳源浓度是:蔗糖30g/L、葡萄糖10g/L.无机盐最佳浓度是:NH+410mmol/L,NO-340mmol/L,PO3-41.25mmol/L.研究表明,培养基的pH值与植板率密切相关.氨基酸及维生素等有机成分能明显促进细胞生长.来自细胞悬浮培养物的条件培养基能显著地促进红豆杉培养细胞的单细胞在低密度植板时的克隆形成  相似文献   

5.
本研究首次观察到在水溶液中溶解有Cl^-,NO3^-,F^-,HCO3^-和SO4^-五种阴离子时,只有F^-在浓度高于4.0mg/L时会对声致发光产生影响,当在4.0mg/L ̄2.0mg/L范围内改变F^-的浓度,声致发光强度随F^-浓度的增加而下降,F^-的引入使得空化区域的低温等离子体的形成变为可以控制。  相似文献   

6.
2,6—二硝基甲苯对鲤鱼的毒性   总被引:10,自引:2,他引:8  
研究测定了2,6-二硝基甲苯(2,6-DNT)对鲤鱼的急性和亚致死毒性.亚致死试验经180mg/L、360mg/L、540mg/L、720mg/L、990mg/L2,6-DNT暴露21d.在15℃~19℃下,24h、48h、72h、96h的半致死浓度值分别为2548mg/L、2296mg/L、2012mg/L、1900mg/L.亚致死试验中,根据2,6-DNT对鲤鱼生长和肝、肾、鳃ATPase活力的影响,求得2,6-DNT的最大允许毒物浓度为180~360mg/L.  相似文献   

7.
金属离子对葡萄糖氧化酶活性测定的影响   总被引:7,自引:0,他引:7  
本文研究了一些金属离子对葡萄糖氧化酶测定的影响,指出Ag+、Hg2+具有较强抑制作用,最小抑制浓度分别为5ug/L及4mg/L,I50分别为20ug/L及7.7mg/L。  相似文献   

8.
稀土对八角种子萌发及幼苗生长的生理效应   总被引:6,自引:0,他引:6       下载免费PDF全文
吕成群  黄宝灵  牟继平 《广西科学》2000,7(3):228-231,240
用0mg/L、50mg/L、100mg/L、200mg/L、300mg/L、500mg/L浓度稀土(RE)处理八角(Illicium verum Hock.f.)种子和幼苗,结果表明:100mg/L浓度RE增加种子发芽时的根长、芽长、侧根数和提高种子活力指数最显著;200mg/L浓度RE提高种子发芽率、发芽指数、日平均发芽率和发芽值最显著;300mg/L浓度RE提高发芽高峰值和降低平均发芽天数最显  相似文献   

9.
流动注射在线光化学荧光法测定扑热息痛   总被引:4,自引:0,他引:4  
提出测定扑热息痛的流动注射光化学荧光分析的新方法,扑热息痛在NaOH碱性介质中,于15W紫外杀菌灯的照射下发生光化学反应,所得产物的荧光强度与扑热息痛的浓度在0-10.0mg/L范围内有良好的线性关系,检测限为0.03mg/L。本法可直接用于片剂中扑热息痛的定量分析。  相似文献   

10.
两种乳化剂对大鳞副泥鳅胚胎,鱼苗的亚慢性毒性   总被引:2,自引:0,他引:2  
参照瑞典制订的欧洲国家标准法的鱼类胚胎-鱼苗毒性测定技术,进行了农乳2201及吐温-80两种常用乳化剂对大鳞副泥鳅胚胎-鱼苗阶段毒性实验。结果表明,鱼苗比鱼卵对这两种乳化剂更敏感,农乳2201对鱼苗的最低影响浓度(LOEC)为0.14mg/L,最高无影响浓度(NOEC)为0.07mg/L,而吐温-80则分别为50、25mg/L。与由经验公式推算的结果相比较,差别比较大,尽管在鱼类毒性试验中通常要求  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.
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   

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.
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   

15.
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   

16.
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   

17.
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   

18.
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   

19.
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-  相似文献   

20.
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-  相似文献   

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