共查询到20条相似文献，搜索用时 57 毫秒
1.
催化动力学光度法测定自来水中的痕量硒（Ⅳ） 总被引：2，自引：0，他引：2
袁兆岭 《临沂师范学院学报》2003,25(6):55-57
在硫酸介质中，硒(Ⅳ)能催化溴酸钾氧化偶氮氯膦mA(CPA mA)的褪色反应．研究了这一催化反应的动力学条件，建立了动力学光度法测定硒(Ⅳ)的新方法，硒的含量在0．3—1.0Oμg／10mL范围内与褪色程度(△A)呈线性关系．该方法具有良好的选择性和准确度，用于自来水中痕量硒(Ⅳ)的测定，结果满意． 相似文献
2.
本文发现了在氨性介质中,痕量铜催化过氧化氢氧化溴甲酚紫褪色的指示反应.研究了催化褪色反应的最佳条件和动力学参数,建立了测定痕量铜的新方法,方法的最低检测限为2.75×10~(-9)g/ml,测定范围0.2—1.0μgCu(Ⅱ)/26ml,用于测定人发中的Cu(Ⅱ),获得了满意的结果. 相似文献
3.
环境水样中NO2-的催化光度法测定 总被引：1，自引：0，他引：1
提出了催化褪色光度法测定痕量NO2-的新方法.此法是基于百里香酚蓝在H2SO4介质中被KBrO3氧化的反应受到痕量NO2-的催化.本法的检测限为4.6×10-8g/mL,测定范围为2～12μg/25mL. 相似文献
4.
宋学省 《临沂师范学院学报》2005,27(3):33-34
在氨水-氯化铵(pH=9.0)介质中,痕量铜(Ⅱ)能灵敏地催化过氧化氢氧化荧光桃红褪色.研究了反应的最优化条件,建立了动力学光度法测定痕量铜(Ⅱ)的新方法.方法线性范围0.05~6ng/mL,检出限为0.077ng/mL.用于水样的测定,结果满意. 相似文献
5.
催化动力学褪色光度法测定痕量锰的研究 总被引：1，自引：0，他引：1
研究了在NH3·H2O-NH3Cl介质中,Mn（Ⅱ）催化高碘酸钾氧化铬黑T褪色反应的适宜条件,讨论了反应的动力学参数,建立了测定痕量锰的新体系。方法的检出限为2.45×10-9g/mL,线性范围为0～0.3μg/25mL。用于茶叶中痕量锰的测定,结果满意。 相似文献
6.
新催化光度法测定痕量钒的研究 总被引：1，自引：0，他引：1
以柠檬酸为活化剂,在硫酸介质中,微量钒(Ⅴ)能显著催化溴酸钾氧化丽春红2R(PR)的褪色反应。研究了该催化反应的最佳反应条件和动力学参数,建立了一个测定痕量钒的新的催化动力学分析方法。方法的线性范围为0.0~1.0μg/25mL,检出限为3.8×10-4μg/mL。用于测定中草药及食品中钒的含量,结果满意。 相似文献
7.
催化动力学法测定痕量溴的研究 总被引：2，自引：0，他引：2
严进 《南通职业大学学报》2002,16(2):12-13
研究了磷酸介质中,痕量Br-催化溴酸钾氧化（?）素红褪色反应及其动力学条件,建立了催化光度法测定痕量溴离子的新方法。Br-的测定线性范围为1-10μg/25ml,检出限为1.19×10-8·ml-1。用于化学试剂及水样中痕量Br-的测定,结果满意。 相似文献
8.
梁国柱 《南通职业大学学报》2004,18(2):77-78
本文研究了在硫酸介质中,痕量铁(Ⅲ)催化过氧化氢氧化茜素红而使其褪色的动力学条件,建立了测定痕量铁的新方法,其灵敏度为2.0×10-9g/mL,线性范围0—7μg/25 mL,用于水样、食品中痕量铁(Ⅲ)的测定,结果令人满意。 相似文献
9.
痕量铜的新催化光度法测定 总被引：1，自引：0，他引：1
研究了铜(Ⅱ)催化双氧水氧化溴百里酚兰褪色的催化效应及动力学条件,建立了测定痕量铜的新催化光度法.该法标准曲线的线性范围为铜(Ⅱ)浓度0～0.5μg/25mL,检出限为0.009μg/25mL,方法简便、快速、准确,用于铝合金中痕量铜的测定,回收率为96.0%～98.3%. 相似文献
10.
基于醋酸——醋酸钠缓冲容液(pH=4.75)中,痕量钯(Ⅱ)催化次磷酸钠还原孔雀绿褪色反应,建立了痕量钯的催化动力学光度分析新方法.方法的最低检测限为2.273×10~(-10)g/ml,线性范围0.1～0.8μg/25ml,方法应用于模拟试样的测定,结果满意. 相似文献
11.
罗艳萍 《读与写:教育教学刊》2008,5(6)
The communication of people partially is the communication of cultures. Culture has a direct effect on international commercial activities in all aspects. Different conceptions about time, space, equality, law and the like, lead people to deal with things in different ways. So to know cultures of the counterpart is to facil-itate our enterprises so as to have a smooth and successful communication in commercial activity. 相似文献
12.
Richard Denner 《海外英语》2007,(4):14-15
Rosco and I wait for the fishermen to return.I sit at a wooden bench near the store at Mt.Baker Resort and watch the clouds change shape. Rosco has my belt around his neck and an eight foot tow chain hooked to a tree. Dogs must be on a leash. Ducks and rabbits are loose. 相似文献
13.
Given a graph G,a subgraph C is called a clique of G if C is a complete subgraph of G maximal under inclusion and |C|≥2. A clique-transversal set S of G is a set of vertices of G such that S meets all cliques of G. The clique-transversal number, denoted as TC (G), is the minimum cardinality of a clique-transversal set in G. The clique-graph of G, denoted as K (G), is the graph obtained by taking the cliques of G as vertices, and two vertices are adjacent if and only if the corresponding cliques in G have nonempty intersection. Let F be a class of graphs G such that F={G|K(G) is a tree}. In this paper the graphs in F having independent clique-transversal sets are shown and thus TC (G)/|G|≤1/2 for all G ∈ F. 相似文献
14.
邱崇丙 《唐山师范学院学报》2014,(1):21-23
汉字的六书,《说文》对“转注”一类,语焉不详。后世学者提及转注,也仅限于许慎所举出的例字。《汉字例说》一文,作者从转注的角度综合考虑,对部分现代常用字作了分析,跟传统的解释有所不同。希望能抛砖引玉,互相切磋,以推进学术研究。 相似文献
15.
16.
陈美曦 《山东教育学院学报》2008,23(2):103-107
Different nations have different social cultures, and the social culture of every nation is developing with the development of the nation, language is greatly influenced by social culture, which enables language to possess national and historical characteristics. Word is the smallest, independent, meaningful linguistic unit of language. It can well reflect the national and historical characteristics. From synchronic aspect, the social and cultural influence on word meaning is mainly embodied in conceptual and associative meanings of word. The incorrespondence of word meaning is a phenomenon that exists in both conceptual and associative meanings of word among different languages. From diachronic aspect, the development of social culture causes some changes of word meaning to some extent. Therefore, social culture plays a key role in vocabulary learning and mastery of a language. 相似文献
17.
Rachel Zupek 《海外英语》2007,(11):40-41
我们绝大部分人都同意一件事情——我们喜欢金钱。但是你对金钱的喜欢之情足够到让你创立一份事业么?.财富通常被人忽视,主要在于人们不能真正了 相似文献
18.
《海外英语》2007,(4):36
There are numbers of crossroads on our long and unpredictable life journey where we totally have no idea about which direction to choose. No matter what our decision is, we should not turn back, but face the music and go ahead instead. I am this kind of girl who always does try without regretting, one example is how I dealt with my love. 相似文献
19.
YANGShiguo 《重庆大学学报(英文版)》2004,3(1):86-88
The problem on the geometrc inequalities involving an n-dimensional simplex and its inscribed simplex is studied. Aninequality is established, which reveals that the difference between the squared circumradius of the n-dimensional simplex andthe squared distance between its circumcenter and barycenter times the squared circumradius of its inscribed simplex is not lessthan the 2(n-1)th power of n times its squared inradius, and is equal to when the simplex is regular and its inscribed siplex is atangent point one. Deduction from this inequality reaches a generalization of n-dimensional Euler inequality indicating that thecircumradius of the simplex is not less than the n-fold inradius. Another inequality is derived to present the relationship betweenthe circumradius of the n-dimensional simplex and the circumradius and inradius of its pedal simplex. 相似文献