共查询到20条相似文献，搜索用时 468 毫秒
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研究了对硝基偶氮羧与铅β型显色反应的条件.在0.048mol·L-1的柠檬酸介质中,试剂与铅形成21的稳定的蓝色络合物,最大吸收波长在725nm,表观摩尔吸光系数为1.79×105L·mol-1·cm-1.铅量在0～35μg/25ml内符合比耳定律.建立了测定微量铅的方法. 相似文献
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冯泳兰 《衡阳师范学院学报》1998,19(6):1-3
研究了在KOH介质中,在聚乙烯酸（PVA）存在下Cd（Ⅱ）离子与1－（4－硝基苯基）－3－[4－（苯基偶氮）苯基]－三氮烯（Cadion）形成1：2配合物,其配合物最大吸收位于530nm处,而使空白试剂最大吸收波长530nm处吸光度下降.利用Cadion试剂的褪色测定微量镉.该法测镉的表观摩尔吸光系数ε530为1．57×105L·mol-1·cm-1,镉含量在0～12μg/25mL范围内符合比尔定律.方法应用于铅渣中微量镉的测定,结果满意． 相似文献
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《安徽教育学院学报》1996,(1)
本文探讨了表面活性剂对 Fe(Ⅲ)—SCN 显色反应的增效作用,研究了Fe(Ⅲ)—SCN—Tween—80显色体系的最佳条件。体系的最大吸收波长为485nm,表观摩尔吸光系数为ε=1.6×10~4L·mol~(-1)·cm~(-1)。在0～1.6ugFe(Ⅲ)/ml 符合比耳定律。方法灵敏、快速,用于自来水样品测定,结果满意。 相似文献
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分光光度法水相快速测定铅 总被引：1，自引：0，他引：1
建立了分光光度水相快速测定铅的新方法。在pH=4.0的Clark-Lubs的缓冲溶液中,痕量的Pb2+在KI存在下使孔雀绿在700nm处的吸光度增加,Pb2+浓度与吸光度呈线性关系。线性范围0.8～5.2mg/L,摩尔吸光系数为2.6×104L·mol-1·cm-1,相对标准偏差为3.4%(n=11)。方法操作简便,快速,用于工业废水中铅的测定,结果令人满意。 相似文献
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双波长分光光度法测定人发中痕量铅 总被引：2，自引：0，他引：2
汤明河 《温州大学学报(社会科学版)》2001,14(3):88-90
以双硫腙为显色剂，拟定双波长增敏吸光法测定人发中痕量铅，实验表明，铅浓度在O．1～12．Oug／25ml的范围内符合比耳定律，相关系数r=O．9994。表观摩尔吸光系数为1．31×10th L·mo-1cm，方法检出限为O．Iug／g，相对标准偏差小于2．0％．发样回收率为96．1％～102．O％。本法方法简便、快速、结果满意。 相似文献
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朱彬 《遵义师范学院学报》2000,(1)
用作者合成的嘶试剂5-(8-喳啉偶氮)-2,3-二羟基吡啶作显色剂,以分光光度法测定微量钴,在PH9.3的硼砂缓冲溶液中,配合物的最大吸收波长在624nm处,钴量在0～20μg/25ml范围内符合比尔定律,表观摩尔吸光系数为9.0×10~4L·10mol(-1)·cm(-1)。方法简便、快速,应用于维生素B_(12)和镍盐中钴的测定,获得满意结果。 相似文献
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杨水平 《赣南师范学院学报》2001,(6):49-51
本文研究了哌啶荒酸哌淀 (PDPC)与Co(Ⅱ )最佳显色反应的条件 ,在 pH =5 .5的条件下 ,Co(Ⅱ )与PDPC形成稳定的黄色络合物 ,络合物组成比为M∶R =1∶2 ,可见光区最大吸收波长λmax=4 0 0nm ,表现摩尔吸光系数ε=2 .2 9× 10 4L·mol- 1·cm- 1.该体系显色速度快 ,稳定性好 .应用拟定方法测定合成水样中Co(Ⅱ )含量 ,结果满意 . 相似文献
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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
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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
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《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
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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
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Migration occurs behind a variety of reasons and has a great effect on the whole world. People may migrate in order to improve their economic situation, or in order to escape civil strife, persecution, and environmental disasters. The impact of migration is complex, bringing both benefits anddisadvantages. This paper briefly talks about the causes of migration, the allocation of benefits, and the ways in which individual countries and the international community deal with this important subject. 相似文献
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GUO Bao-feng Xiao Da-wei 《重庆大学学报(英文版)》2005,4(3):129-133
Using virtual reality for interactive design gives a designer an intuitive vision of a design and allows the designer to achieve a viable, optimal solution in a timely manner. The article discusses the process of making the Virtual Reality System of the Humble Administrator＇s Garden. Translating building data to the Virtual Reality Modeling Language （VRML） is by far unsatisfactory. This creates a challenge for computer designers to do optimization to meet requirements. Five different approaches to optimize models have been presented in this paper. The other methods are to optimize VRML and to reduce the file size. This is done by keeping polygon counts to a minimum and by applying such techniques as object culling and level-ofdetail switching. 相似文献
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The awareness of individualism can be traced back to the period of American Revolution when the Declaration of Independence was produced.It expressed basic beliefs concerning freedom,equality,democracy,privacy and the relationship between people and government,which were exactly what the philosophy of individualism mostly dealt with at that time.This paper is to exploit the essence of individualism by analyzing the Declaration .The analysis enables us to reconsider its significance to the issue of America human rights and foreign policies. 相似文献
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Sister Carrie is one of the most controversial characters in American literature.Thought as a "fallen woman" firstly,she was defined as a "new woman" by some critics later. However, by digging into the motivaton behind the whole process of Carrie's "success", the relationship between Carrie and her creator (the author), the social conditions of then American, it can be found that Carrie has never been free-standing on her thought and she has never found her real-sdf even after becoming a famous actress. In a society dominated by mass consumerism Carrie is only an adherent of her own desires. She also is a representative of all those country girls flooded into cities, a symbol and a sacrifice of the urbanization of America in a time countryside was overcome by cities. 相似文献