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1.
本文研究了在聚乙烯醇和Tritonx—100存在下,镉(Ⅱ)—碘化钾—丁基罗丹明B离子缔合物显色反应的条件。络合物最大吸收峰在600nm,摩尔吸光系数为2.2×10~5l·mol~(-1)·cm~(-1)。镉量在0.5-4.0μg/25ml范围内服从比尔定律。试验了若干种离子的干扰,此法已用于自来水中微量Cd~(2+)的测定。  相似文献   

2.
本文报告了新显色剂2,4——二溴苯重氮氨基偶氮苯的合成、纯化及结构分析,并研究了试剂与镉的显色反应。研究结果表明:在TritonX—100的存在下,于pH10.0的Na_2B_4O_7-NaOH缓冲介质中,镉可与试剂生成1:2的橙红色配合物,配合物的λ_(max)=490nm,表观摩尔吸光系数ε_(490)=1.04×10~5L·mol~(-1)·cm~(-1)。镉量在0—0.8μg/ml范围内遵循比尔定律。方法用于铝合金样品及合成水样中痕量镉的测定,结果满意。  相似文献   

3.
报道新试剂乙氧基苯并噻唑重氮氨基硝基苯(EtOBTDANB)的合成,并研究了该试剂与镉的显色反应。实验表明,在Triton X—100存在下,pH=10.3—10.8的Na_2B_4O_7—NaOH缓冲体系中,镉与试剂形成1:1的橙黄色络合物,最大吸收位于395nm,而在495nm处络合物与试剂的吸收差值最大,若以395nm为参比波长,495nm为测量波长时,其ε=2.95×1O~5L·mol~(-1)·cm~(-1),镉含量在O-240ug/L范围内符合比耳定律,并对地面水与人发中镉含量进行了测定,结果满意。  相似文献   

4.
本文报道了新显色剂3—氯—4(2-硝基—4—甲基苯基重氮氨基)偶氮苯的合成及其与镉的显色反应。在非离子表面活性剂Triton X—100存在下,于pH9.5的Na_2B_4O_7—NaOH缓冲溶液中,试剂与镉生成2:1的红色配合物,其配合物的最大吸收波长位于524nm处,表观摩尔吸光系数ε=1.34×10~5L·mol~(-1)~cm~(-1),镉量在0 12μg/25ml范围内符合比尔定律,方法曾用于标准水样及电镀废水中微量镉的测定,结果满意。  相似文献   

5.
本文研究了新显色剂2,6一二氯-4-氨磺酰基苯基重氮氨基偶氮苯的合成和性质及其与镉的显色反应。在非离子表面活性剂TritonX-100存在下,于pH11.0的硼砂一氢氧化钠缓冲溶液中,显色剂与镉形成稳定的红色配合物,其最大吸收波长位于520nm,摩尔吸光系数为1.84×10~5l·mol~(-1) ·cm~(-1)。镉含量在0-10μg/25ml 范围内符合比尔定律,方法用于工业废水中痕量镉的测定,结果令人满意。  相似文献   

6.
研究了黄河水中表层沉积物与镉液 -固界面相互作用的离子交换率E(% ) -pH曲线 ,以及河水中甘氨酸的存在对该曲线的影响 .实验结果表明 :1)镉是以Cd(OH) 形式在沉积物表面进行阳离子交换反应 .pH值是控制Cd 向固相迁移的主要因素 ,离子交换率E(% )随pH升高而增大 ,且在天然河水 pH为 8.0~ 8.5下接近最大值 ;2 )镉离子浓度由8.9× 10 - 7mol·L- 1 增大到 3× 8.9× 10 - 6mol·L- 1 时 ,离子交换率降低 ;3)河水中有2 .7× 10 - 6 mol·L- 1 甘氨酸存在时 ,会提高离子交换率 ;4 )转化沙和未转化沙分别对镉的吸附作用不同 ,后者大于前者 ,与理论推断相一致 .  相似文献   

7.
本文报道了四种三氮烯类新显色剂的合成与纯化方法,以及这些试剂在TritonX—100存在下与Cd(Ⅱ)的显色反应。实验表明:显色介质的酸度对试剂与Cd(Ⅱ)的显色反应影响很大,在最佳显色pH值下,试剂Ⅰ—Ⅳ都能与镉形成稳定的红色配合物,其最大吸收波长位于500nm左右,摩尔吸光系数都在1.0×10~5l·mol~(-1)·cm~(-1)以上。  相似文献   

8.
本文研究了在聚乙烯醇—124存在下,C_d~(2+)—I~-—罗丹明6G高灵敏度显色体系。用加权单纯形最优化法进行了最佳实验条件的选择。缔合物的λ_(max)=560nm。表观摩尔吸光系数ε_(560)=9.5×10~4l·mol~(-1)·cm~(-1)。测定了络合物的组成,研究了20多种共存离子对测定的影响。方法用于纯铝、纯锌中镉的测定。  相似文献   

9.
本文提出了以2—(3,5—二氯—2—吡啶偶氮)—5—二甲氨基苯胺作显色剂同时测定钴、钯的新方法。在实验条件下,钴、钯与试剂分别形成1∶2和1∶1的稳定配合物。其表现观摩尔吸光系数分别为ε(?)=1.16×10~5L·mol~(-1)·em(-1),ε(?)=7.68×10~4L·mol~(-1)·cm~(-1)。钴浓度在0—0.6μg·ml~(-1),钯浓度在0—0.4μ·ml~(-1),范围内符合比尔定律。本方法简便、快速、选择性高,用于分子筛中微量钴、钯的同时测定,结果满意。  相似文献   

10.
新试剂邻羧基苯基重氮氨基偶氮苯对镉有灵敏显色反应,摩尔吸光系数可达1.94×10~6升·摩尔~(-1)·厘米~(-1)。本文报导了它的合成及吸光性能。又通过十六种新合成的该类衍生物与镉的显色反应,发现了不同结构的各类取代基与吸光性能关系的规律性。  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.
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   

19.
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   

20.
正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that  相似文献   

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