共查询到20条相似文献，搜索用时 62 毫秒
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利用一种新型水溶性吡啶卟啉季铵盐即溴化5-[(4-N-正丁基)吡啶基]10,15,20-(4-N-吡啶基)卟啉作为显色剂,研究了该试剂与锌的显色反应.在pH值3.0的邻苯二甲酸氢钾-盐酸缓冲溶液中,形成了配位比为1 1的络合物,其最大吸收波长λ=424 nm,表观摩尔吸光系数ε=1.87×105L.mol-1.cm-1.在0-0.14ug/mL范围内吸光度与锌质量浓度关系符合比尔定律,该法灵敏度高、选择性好.应用于环境水试样中痕量锌离子的分析,结果满意. 相似文献
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1-（4-硝基苯基）-3-（5-溴-吡啶）-三氮烯的合成及其与铜的显色反应 总被引：1，自引：0，他引：1
报道了1-(4-硝基苯基)-3-(5-溴-吡啶)三氮烯(NPBPDT)的合成及其与铜的显色反应．在NP-10的存在下，pH11．0的Na2B4O7-NaOH缓冲溶液中，该试剂能与铜发生显色反应，铜与NPBPDT形成摩尔比为1：2型的黄色配合物，在440m处有一最大正吸收峰，在540nm处有一最大负吸收．以440nm为参比波长，540nm为测量波长进行双波长测定，表观摩尔吸光系数为1．91×10^5L·mol^-1·cm^-1，铜的浓度在0-12μg／25mL范围内遵守比尔定律．用拟定方法测定铝合金中的微量铜，结果满意． 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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研究了用间硝基苯基荧光酮(m-NPF)做显色剂在表面活性剂——溴代十六烷基三甲胺(CTMAB)的存在下与锌离子的反应,实验证明在PH=6.25时,生成红色络合物,其最大吸收波长为498nm,表观摩尔吸光系数为ε=1.357×105L/mol.cm,在0-8ug/25mL范围内符合比耳定律,用于测定水样,结果比较满意. 相似文献
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《洛阳师范学院学报》2016,(2):51-53
在酸性条件下,NO_2~-可以将I-氧化成I_2,I_2与淀粉反应后生成蓝色络合物,此络合物在595nm处有最大吸收.食品中NO-2的浓度在2.0×10-4~7.0×10-6g.m L-1范围内与吸光度之间呈良好的线性关系,其标准曲线的回归方程为A=-0.01841+0.10196c,r=0.9995.所得方法的相对标准偏差为0.7%,检出限为5.0×10-8g.m L-1.该方法精密度和准确度高、操作简单、环境污染小. 相似文献
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研究了以乳化剂OP／正丁醇／正庚烷／水组成的微乳液为介质,5-Br-PADAP为显色剂,分光光度法测定铜的实验体系．结果表明：在波长为554nm下,铜离子浓度在0-6μg／10mL范围内符合比尔定律,相关系数r为0．9995,摩尔吸光系数ε为1．2×10^5L·moL^-1·cm^-1．该方法用于各类蜂花粉样中铜的测定,回收率达到91．5％～107．0%． 相似文献
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1-(5-硝基2-吡啶偶氮)-2.7-萘二酚分光光度法测定微量铜的研究 总被引：1，自引：0，他引：1
研究了用新试剂 1 (5硝基 2吡啶偶氮 ) 2 .7萘二酚 (5 NO2 PADN)分光光度法测定微量铜 ( )的适宜条件。结果表明 ,在非离子表面活性剂 Tween 80存在下 ,于 p H5.5～ 6.5HAc Na Ac缓冲溶液中 ,5 NO2 PADN与铜 ( )反应生成稳定的配合物 ,其最大吸收波长 λmax=570 nm,表观摩尔吸光系数 ε=4.4× 1 0 4mol·L1·cm1。铜 ( )浓度在 0～ 7μg/ 1 0 ml范围内服从比耳定律。所拟方法用于水样中微量铜 ( )的测定 ,结果满意 相似文献
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陶月潮 《安徽科技学院学报》2003,17(4):351-354
本文研究了均三溴偶氮胂光度法测定地下水中微量锶的方法。试验表明,在弱酸性介质中,锶与均三溴偶氮胂生成稳定的络合物,络合物的最大吸收波长为618nm,摩尔吸光系数达2.55×10~4L·mol~(-1)·cm~(-1),该方法简便、快速、准确。 相似文献
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在0．24mol·L~1磷酸介质中,铅与二澳对甲基偶氯甲磺形成1:2蓝色络合物,最大吸收波长642urn,表观摩尔吸光系数为7．68×10~4L·cm~1,铅量在0－15/25ml内符合比耳定律,方法应用于铝合金中微量铅的测定,结果满意． 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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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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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
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RUZBEHANI Mohsen 《重庆大学学报(英文版)》2004,3(1):20-25
1.IntroductionOne-cyclecontrolmethod,whichwasproposedaboutonedecadeago[1],hasbecomeanattractivemethodinspecialfieldssuchaspowerfactorcorrection[2-6],switchingamplifiers[7,8],etc.Themainideaofthiscontrollerisbasedonintegrationofdiodevoltageinone-cycleandforcesittobeexactlyequaltothereferencevalue.Themainadvantageofthiscontrollerisitsrealtimeabilitytorejectthevariationofinputvoltage[1].Despitethisgreatability,ithasnogoodperformancesinrejectingofloaddisturbanceandfollowingreferencecommands.Espec… 相似文献
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Rajesh Kanoi 《海外英语》2007,(1):52
Today, Sunday morning, I sit thinking and typing at my computer. My thoughts are in my homeland, India and my body is in China. The body is here and mind there for a good reason. Mr. Hu is president and I am resident and both are in each other's countries (what a difference the absence of one small letter makes!). Mr. Hu will return in a few days and I will stay on longer. 相似文献
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正A One day a pig went to the stable(马棚)to see his good friend,an oldhorse,and was going to stay there forthenight.Night came and it was time forsleep.The pig went into the straw heap(稻草堆)and lay comfortably.A longtime passed,but the horse was stillstanding there and did not move.Thepig asked the horse why he did not go tosleep."Standing like this is the begin-ning ofsleeping,"answered the horse. 相似文献
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《今日中学生》2014,(9)
正1.Any fool can count the seeds in an apple.Only God can count all the apples in one seed.2.Happy families are all alike;every unhappy family is unhappy in its own way.3.Memories are the key not to the past,but to the future.4.Sometimes in the dark you see what you want to see.5.There is a great difference between 相似文献
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《重庆大学学报(英文版)》2014,(2)
正Scope and Policy The Journal of Chongqing University-English Edition(JCQU-E)is a peerreviewed journal publishing research articles in multiple disciplines of science and technology,covering civil and environmental engineering,chemical engineering,biotechnology,mechanical and electrical engineering,computer and data processing,mining,metallurgy,materials science,and interdisciplines thereof. 相似文献