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1.
报道了以铂(Ⅳ)催化溴酸钾氧化二溴羧基偶氮胂的褪色反应,建立了一种在水相中直接测定微量铂的催化光度分析法.铂含量在1.0~25.0 μg·L-1范围内符合比耳定律.检出限量为1.0μg·L-1.用于铂-铑催化剂和铂-钯精矿中铂的测定,结果满意.  相似文献   

2.
基于稀H2SO3介质中,痕量钛(Ⅳ)催化KBrO3氧化二溴羧基偶氮胂(DBCAA)的褪色反应,建立了测定痕量钛(Ⅳ)的催化动力学光度法.方法检出限为0.15μg/L,线性范围为0.0~8.0μg/L.结合溶剂萃取分离,可用于测定人发、植物、茶叶及岩石样品中的痕量钛(Ⅳ).  相似文献   

3.
报道了以铑(Ⅲ)催化溴酸钾氧化二溴羧基偶氮肿的褪色反应,建立了一种在水相中直接测定微量铑的催化光度分析法.铑含量在0.0~10.0μg·L-1范围内符合比耳定律.用于铂-铑催化剂中铑的测定,结果满意.  相似文献   

4.
基于稀盐酸介质中,溴酸根氧化灿烂甲酚蓝的褪色反应,建立了测定痕量溴酸根的新的褪色光度分析方法,对反应的条件进行了优化,在测定波长630 nm及选择的实验条件下,溴酸根的含量在0.0~3.0μg·m L-1,灿烂甲酚蓝的褪色速率(ΔA)与CBr O3-呈正比例关系,校准曲线方程为ΔA=0.2053CBr O3-+0.0052,相关系数r=0.9993.检出限为4.16×10-5g·m L-1该方法在室温下进行,操作方便,可用于饮用水中痕量溴酸根的测定.  相似文献   

5.
报道了以铑(Ⅲ)催化溴酸钾氧化偶氮胂Ⅲ的褪色反应,建立了水相中直接测定微量铑的催化光度分析法.铑含量在1.0~30.0μg·L-1范围内符合比耳定律,测定限1.0μg·L-1.用于铂 铑催化剂的测定,结果满意.  相似文献   

6.
以铑(Ⅲ)催化溴酸钾氧化二溴邻硝基偶氮胂的褪色反应,建立了一种在水相中直接测定微量铑的催化光度分析法.铑含量在0.0-20.0μg.L-1范围内符合比耳定律.用于铂-铑催化剂中铑的测定,结果令人满意.  相似文献   

7.
以H2SO4为介质,在TritonX-100存在下,5-Br-PADAP与钒(V)生成紫色络合物,采用双峰双波长分光光度法进行测定,结果表明,试剂和络合物的最大吸收波长分别为470nm和600nm,钒(V)的含量在0~30μg/25mL范围内符合朗伯-比耳定律,表观摩尔吸光系数ε=3.76×104L·mol-1·cm-1,比单波长法(ε=1.77×104L·mol-1·cm-1)提高2.1倍,用于钢样中微量钒的测定,结果令人满意.  相似文献   

8.
在硫酸介质中,Ce(]V)对靛蓝胭脂红有褪色作用,并且与存在的Ce(Ⅳ)量在一定范围 内呈线性关系,由此建立了分光光度法测定铈的新方法。褪色体系的最大吸收波长为610 nm,表观摩尔吸光系数为2.72 x 103 L/mol/cm,方法的线性范围为0. 2?7. 8 μg/mL,检出限 为7. 2 x 1 0 — 3μg/mL。该方法简单、快速、准确、选择性好,线性范围宽,用于测定水样中的微 量铈,结果满意。  相似文献   

9.
在磷酸-氯化钠介质中,痕量Ir( Ⅳ)催化高碘酸钾氧化乙基橙(EO)的褪色反应,催化剂的浓度在一定范围与ΔA(非催化体系吸光度A0与催化体系吸光度A的差值)成线性关系,据此建立了分析痕量铱的新方法.该方法的线性范围为1.2×10-5~3.6×10-5g.L-1,检出限为6.0×10-6g.L-1,测定11次的RSD为5.0%.该法用于合成试样中痕量铱的测定,结果令人满意.  相似文献   

10.
研究二苯并18-冠-6冠醚交联壳聚糖对砷的吸附行为,建立了石墨炉原子吸收法测定环境水中痕量砷的形态分析方法,探讨了最佳分析条件.该法用于分析实际环境水样富集倍数达50倍以上,用2 mL 0.40 g·L-1酒石酸洗脱可直接测定有机砷含量,用2 mL 4 mol·L-1 HCl洗脱可直接测定无机砷含量.该法用于环境水中超痕量砷的形态分析测定,回收率达94%~105%,检出限(3σ)为0.20 μg·L-1,相对标准偏差为2.6%~3.2%.  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.
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   

14.
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   

15.
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   

16.
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   

17.
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   

18.
For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the  相似文献   

19.
Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of  相似文献   

20.
<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with  相似文献   

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