锌和镉与均苯三酰胺甘氨酸配合物的合成与荧光性能研究

以均苯三酰胺甘氨酸为配体,合成了[Zn3L2·15H2O]n(1)和[Cd3L2·DMF·7H2O]n(2)(L=均苯三酰胺甘氨酸,DMF=N,N-二甲基甲酰胺).并对其进行了元素分析、红外光谱、热重分析、X-射线粉末衍射和荧光光谱测定,与配体相比,[Zn3L2·15H2O]n(1)和[Cd3L2·DMF·7H2O]n(2)的荧光光谱发生了不同程度的红移和蓝移,其最大发射峰分别在467nm和428nm.     

微波消解-分光光度法测定面食中的铝含量

用微波消解-分光光度法测定面食中的铝含量.用微波消解对面食进行了预处理,采用分光光度法测定其中的铝含量.经过实验测定的最优条件为:λmax=615nm,抗坏血酸的用量为1.00mL,铬天青S的用量为2.50mL,显色时间为30min,pH=6.7～7.0,铝在0～0.2μg/mL范围内线性良好,线性回归方程为Y=0.0...     

酸性铬兰 K 催化光度法测定抗坏血酸的研究

在酸性介质中,抗坏血酸对溴酸钾-酸性铬兰K-钒催化体系具有显著的活化作用,据此建立了测定抗坏血酸的新方法,并探讨了动力学条件.方法的测定范围为0.8μg～30μg/mL,检出限为2.09×10-7g/mL.方法用于药品中抗坏血酸的测定,结果满意.     

甘氨酰二肽与乙酸钠相互作用的电导研究

测定了298.15 K条件下乙酸钠在三种甘氨酰二肽(甘氨酰甘氨酸,甘氨酰-L-缬氨酸和甘氨酰-L-亮氨酸)水溶液中的电导率,计算了乙酸钠在这些体系中的极限摩尔电导率和walden值.结果表明:电解质乙酸钠在甘氨酰二肽一水混合溶剂中的极限摩尔电导率随着混合溶剂中肽浓度的增加而减小,waIden值不为常数.     

均苯三酰胺甘氨酸配合物镉(Ⅱ)的合成与表征

均苯三酰胺甘氨酸(L)与Cd(NO3)2·6H2O加入到20mlH2O/DMF(2:1)溶液中,高压釜下加热到200℃,并保持12小时,生成一种新的化合物[Cd3(L)2(DMF)(H2O)5]n,并用荧光光谱、红外光谱,XRD和元素分析等手段对其结构进行了表征.     

间接分光光度法测定药物中的抗坏血酸

在表面活性剂CTMAB存在下,抗坏血酸能够定量还原Fe(Ⅲ)为Fe(Ⅱ)离子,利用显色剂5-Br-PADAP建立了间接分光光度法测定抗坏血酸的方法,在pH=5.6的六次甲基四胺-盐酸缓冲溶液中,Fe(Ⅱ)-5-Br-PADAP-CTMAB络合物的最大吸收峰位于730nm处,抗坏血酸的含量在2.0～20 μg/25mL范围内符合比耳定律,表观摩尔吸光系数ε730=4.53×104L·mol-1·cm-1.本法用于维生素C片剂及注射液中抗坏血酸含量的测定,与碘量法对照,结果令人满意.     

酸性铬兰K催化光度法测定抗坏血酸的研究

在酸性介质中,抗坏血酸对溴酸钾—酸性铬兰K—钒催化体系具有显著的活化作用,据此建立了测定抗坏血酸的新方法,并探讨了动力学条件。方法的测定范围为0.8μg~30μg/mL,检出限为2.09×10-7g/mL。方法用于药品中抗坏血酸的测定,结果满意。     

铬天青S分光光度法测定蒸煮食品中铝含量

采用铬天青S在有溴化十六烷基三甲基胺作为表面活性剂、抗坏血酸作为掩蔽剂的条件下,与Al3+反应生成络合物,从而建立一种测定金属铝的分光光度法.在最大吸收波长498nm处,对乙酸-乙酸钠缓冲溶液、溴化十六烷基三甲基胺浓度、铬天青S浓度以及显色时间等条件优化.在0.2～1.0μg/mL之间有良好的线性关系,并测定馒头中铝含量分别为10.44mg/kg和9.768mg/kg,含量符合国家食品安全标准,样品回收率在80%～102.85%.     

荧光法快速检测水果和蔬菜中的抗坏血酸

维生素C(抗坏血酸)经Cu2+氧化为脱氢抗坏血酸,在一定条件下与邻苯二胺反应生成具有荧光的物质.基于此,建立了一种新的测定维生素C的荧光分析法.实验中对氧化剂Cu2+及邻苯二胺的用量、缓冲液介质等进行了优化,在优化条件下,维生素C的浓度在0.05～5.00 μg/mL与其对应荧光强度呈良好的线性关系,相关系数R2=0.998 7;检出限为0.03 μg/mL;对3个不同浓度的样品进行加标回收实验,其回收率为88.91％ ～92.25％;对1.0μg/mL的样品测定3次,测定结果的相对标准偏差为1.98％.将该法用于西红柿、青椒等水果及蔬菜中维生素C含量的测定,结果令人满意.     

二溴对磺酸基偶氮胂分光光度法测定铝

在p H 6.0的NH4Ac-HAc缓冲溶液中,铝(Ⅲ)与二溴对磺酸基偶氮胂发生显色反应生成紫红色络合物。络合物最大吸收波长为610 nm,铝(III)含量在0¹.4μg/ml范围内与吸光度值呈良好的线性关系,其线性回归方程为:A=0.6930C(C:μg/ml)+0.0211,相关系数γ=0.9992,方法检出限为12.2 ng/m L。该方法已成功地测定了河水水样中的铝,10次测定相对标准偏差为2.59%,方法加标回收率为102.1%。     

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.