电化学发光法测定人发中的铜

采用阳极溶出伏安法分离富集铜，并选用盐酸羟胺作发光试剂，结合流动注射技术建立了一种新的电化学发光测定铜的分析方法．该法选择性好、灵敏度高．其线性范围是6．0×10-7~4．0×10-10kg／L铜，RSD是3．2％（n＝11；Cs＝1．0×10－7kg／L），检测限是1．0×10－10kg／L铜，可用于人发中铜的测定．     

维生素B_6的伏安法测定

本文用伏安法对药物中的维生素B6（VB6）进书测定。在0．05mol／L（CH3）4NBr－（CH3）4NOH底液中（pH-6．0～11．0），VB6在-1．88V（VS，SCE）产生一灵敏还原峰，峰高与VB6浓度在8．0×10-7～2．2×10－5mol／L范围内成线性关系，检测下限为2．0×－7mol／L，用本法，可直接测定药物中VB6的含量。     

吲哚乙酸与磷钨杂多酸反应及其极谱分析的研究

在NH3－NH4Cl缓冲溶液（pH=9．5）中,吲哚乙酸与磷钨杂多酸的还原产物在滴汞电极上于－1．70V（vs．SCE）处产生一灵敏的极谱波,该波波高与吲哚乙酸在1．0×10－7～4．0×10－7mol／L范围内成线性关系,检出限为50×10－8mol／L。加标回收实验5次,测定结果的平均回收率为99．7％,RSD为1．09％．     

亚铁氰化钾修饰碳黑微电极测定抗坏血酸

研究了抗坏血酸(AA)在亚铁氰化钾修饰碳黑微电极上的电化学行为。实验结果表明,在pH7．0的磷酸盐中,AA在该电极上的线性范围为2．0×10-6-4．0×10-3mol／L;检出限(3σ)为1．0×10-6mol／L。用这种电极测定抗坏血酸的含量,结果满意。     

中性载体配位推动La（Ⅲ）在水／硝基苯界面传递的伏安行为

采用半微积分伏安法研究了DAM（L）配位推动La（Ⅲ）离子在水／硝基苯界面的传递行为．在0.01mol/LLaC13(W)－0.05mol/LTBATPB（NB）中,ep与CL成正比,线性范围为3．0×10-5-7．0×10-4mol／L,可作L的定量分析．本文对转移机理进行探讨,测定了配合物的形成常数等．     

存在pH值为4的FeCl_3溶液吗

96年全国高考上海化学试题第22题的命题“pH值为4的FeCl3溶液……”．是否存在PH值为4的FeCl3溶液呢？对于这个问题,我们不妨分析一下．在FeCl3溶液中存在水解平衡：Fe3＋＋3H2OFe（OH）3＋3H＋已知KspFe（OH）3＝4×10－38,Kw＝10×10－14设FeCl3溶液中[Fe3＋]＝0．1mol／L,Fe3＋完全沉淀为Fe（OH）3时的[Fe3＋]＝1．0×10－6mol／L根据溶度积公式,可以求得Fe3＋开始形成Fe（OH）3沉淀的pH值为1．87．同理,也可以求得pH值为4时溶液中Fe3＋的浓度．[Fe3＋]＝Ksp／[OH－]3＝4×10-38／（10-10）3＝4×10-8（mol／L）…     

铅(Ⅱ)──胱氨酸配合物吸附伏安特性的研究

本文研究了铅（Ⅱ）-胱氨酸-甘氨酸体系在悬汞电极上的吸附伏安特性。在0．001mol／L甘氨酸溶液中（pH=8．2），加入铅（Ⅱ）溶液后，使胱氨酸的峰电流增大，最佳实验条件下，该峰电流与优氨酸浓度在3．3×10－8～1．0×10－6mol／L范围内呈良好的线性关系，检测限过3．3×10－9mol／L。通过对该峰的性质及反应机理的研究，证明此峰为配合物吸附还原峰，吸附反应物为铅（Ⅱ）与胱氨酸形成的1：1配合物，电机反应为二电子还原。     

水及饮料中铜含量测定研究──巯基棉分离富集、离子选择电极法

采用巯基棉分离富集痕量铜,用3mol．L-1HCl作洗脱剂洗脱富集在巯基棉上的铜,结合离子选择电权法建立了水饮料中痕量铜的离子选择电极分析方法．该法简单、分析灵敏度高,选择性好,检出限量8．30×10－8mol·L－1铜。相对标准偏差为3．8％（n＝7;Cs＝7．2×10－7mol．L－1Cu2＋）．     

高锰酸钾-H_2SO_4-安乃近化学发光体系的研究

在酸性溶液中,高锰酸钾可直接氧化安乃近,产生很强的化学发光,由此建立了一各测定安乃近的流动注射化学发光分析法．方法的检出限为3．1×10-8g／mL,相对标准偏差为1．8％（6．0×10－6g／mL安乃近,n＝11）,线性范围为1．0×10－7～1．0×10-4g／mL,此法已用于安乃近针剂和片剂中安乃近含量的测定．并对该反应的机理进行了探讨．     

荧光熄灭的氟离子光化学敏感膜的研究

基于氟离子对固定于聚氯乙烯(PVC)膜中的8羟基喹啉铝(Alq3)有不可逆的荧光熄灭作用,研制成测定氟离子的选择性光化学敏感膜,并对其性能进行了初步探讨.该膜制作简单,成本低,对于氟离子在5×10-6～5×10-2mol/L浓度范围内时,其荧光强度降低值与氟离子浓度具有良好的线性关系,检出限为2.5×10-6mol/L,相对标准偏差RSD为2.0%,适合于水相中的氟化物测定.     

卡思卡特城堡

It is worthy of noting that, whilst Crookston Castle witnessed the earlier and happier portion of Mary's variegated life,     

不同的吃喝玩乐

一、吃和喝吃苹果 eat an apple, 吃药 take medicine,吃糖 have some sweets,吃饭 have one's meals,吃馆子 dine out,吃惊 be surprised/     

漏洞百出的教育

Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help?     

只要努力,不要后悔

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.     

浅谈移民问题

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.     

Sister Carrie, an Adherent of Desires

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.     

Improvement of one-cycle controller by use of proportional integral differential controller

1.IntroductionOne-cyclecontrolmethod,whichwasproposedaboutonedecadeago[1],hasbecomeanattractivemethodinspecialfieldssuchaspowerfactorcorrection[2-6],switchingamplifiers[7,8],etc.Themainideaofthiscontrollerisbasedonintegrationofdiodevoltageinone-cycleandforcesittobeexactlyequaltothereferencevalue.Themainadvantageofthiscontrollerisitsrealtimeabilitytorejectthevariationofinputvoltage[1].Despitethisgreatability,ithasnogoodperformancesinrejectingofloaddisturbanceandfollowingreferencecommands.Espec…     

库克斯顿城堡

城堡, 是欧洲典型的建筑之一, 每个城堡都有一个美丽的传说或是一段历史。从本期开始, 我们将推出“城堡之旅”, 带各位读者去浏览、观赏欧洲各地的城堡, 开始一段文化与历史的旅途!     

The Reader Response Approach to Teaching of English Literature

During interview with English majors, it was found that a majority of students expressed disappointment with their experience of English literature classes. Students' dislike of learning English literature appears to be the major problem of teaching English literature in China. Reader response approach is a good way to solve this problem. In this paper, I explain the rationale behind the reader response approach, such as its origin, definition, features, assumptions, and strategies. Then I illustrate how reader response approach works as a teaching strategy by presenting several teaching models. At last I evaluate its usefuiness for teachers and present the advantages of reader response approach in Chinese context.