空气—乙炔火焰间接原子吸收法测定茶叶中的铝

間接原子吸收法依据的交換反应如下: Cu(Ⅱ)—EDTA+PAN+Al~(3+)(?) Cu(Ⅱ)—PAN+Al(Ⅱ)—EDTA。Al~3从Cu(Ⅱ)—EDTA絡合物中定量交換Cu~(2+),生成物Cu(Ⅱ)—PAN被氯仿萃取,用空气—乙炔火焰測定水相中剩余的銅,从而間接測定鋁。本方法的灵敏度为0.02ppm。測定了七种茶样中鋁的含量,回收率为94.0～99.3%。     

黑曲霉HD-404酸性蛋白酶若干动力学性质的研究

研究金属离子、EDTA、表面活性剂、碘乙醚等对黑曲霉HD-404酸性蛋白酶活力的影响的结果表明:Cu~(2+)、Mn~(2+)对酶有明显的激活作用;Cu~(2+)、Mn~(2+)和Al~(3+)同时使用时,产生协同效应,显著提高酶活力;十二烷基磺酸钠(SDS)、西湖高效洗洁剂对酶有明显的抑制作用;在以酪蛋白为底物时,AgNO_3是酶的不可逆抑制剂。     

赤楠叶二氯甲烷部位、乙酸乙酯部位抗氧化活性的比较研究

通过测定1,1-二苯基-2-苦基肼(1,1-Diphenyl-2-picrylhydrazyl,DPPH)自由基清除率、还原力、金属离子对其抗氧化活性的影响及总酚质量分数等比较赤楠叶二氯甲烷部位、乙酸乙酯部位的抗氧化活性。结果表明:赤楠叶二氯甲烷部位、乙酸乙酯部位清除DPPH的EC50为0.63、0.10 mg/m L;还原力的EC50分别为0.87、0.09 mg/m L。除Al~(3+)、Fe~(3+)外,K~+、Na~+、Mn~(2+)、Mg~(2+)、Cu~(2+)、Zn~(2+)、Ca~(2+)等金属离子对赤楠叶乙酸乙酯部位的DPPH清除作用为抑制作用;除Cu~(2+)、Ca~(2+)外,K~+、Na~+、Mn~(2+)、Mg~(2+)、Al~(3+)、Zn~(2+)、Fe~(3+)等金属离子对赤楠叶二氯甲烷部位的DPPH清除能力有促进作用。赤楠叶二氯甲烷部位、乙酸乙酯部位的总酚质量分数分别为9.23%与59.17%。可见,赤楠叶乙酸乙酯部位具有较强的抗氧化活性与总酚含量,但其抗氧化活性较易受金属离子的拮抗作用。     

单点络合返滴定的研究

根据络合返滴定中的络合平衡,推导了离子选择电极指示单点络合返滴定的计算公式和滴定曲线表达式,讨论了单点络合返滴定中测定结果的相对误差与电位测定误差之间的关系。用镉离子选择电极示指示电极,以 EDTA 为络合剂,Cd(NO_3)_2为返滴定剂,对 Zn~(2+),Cu~(2+),Al~(3+)Ti~(4+)分别进行了测定。结果表明,本法的测定误差与一般容最分析相近。还用本法测定了矾土试样中 Al_2O_3和 TiO_2的含量。     

圆二色谱法分析金属离子对鲍鱼脯氨酰内肽酶的作用

使用原核表达系统表达了皱纹盘鲍(Haliotis discus hannai)脯氨酰内肽酶(prolyl endopeptidase,PEP),并对其进行高度纯化。SDS-PAGE结果表明,该酶的相对分子质量约为85 ku,其二级结构主要由α-螺旋(28.3%)、反向平行结构(17.4%)、平行结构(8.70%)、β转角(19.0%)、无规卷曲(28.5%)组成。选取PEP特异性荧光底物Suc-Gly-Pro-MCA测定其活性,并选取了多种常见金属盐溶液对其进行抑制作用分析。结果发现,Al~(3+)、Cu~(2+)、 Zn~(2+)、Ag~+和Pb~(2+)能够抑制PEP的活性。利用圆二色谱法,对金属离子作用下PEP的二级结构变化进行分析和计算。分析结果表明,不同金属离子对PEP的作用效果不同:Al~(3+)、Cu~(2+)和Zn~(2+)在影响PEP结构时也影响其活性;Ca~(2+)、Mg~(2+)对PEP的结构和活性均不产生明显影响,而Ag~+和Pb~(2+)可在不影响PEP二级结构的前提下抑制其活性。     

铬天青S光度法测定刺梨中微量铝

在PH4～6的弱酸性介质中,Al~(3+)铬天青S生成紫红色络合物。刺梨中少量的Fe~(3+)和Cu~(2+)用抗坏血酸和硫脲掩蔽。铝含量在0～25μg/25ml范围内遵守比尔定律。适用于刺梨中微量铝的测定。     

基于聚丙烯酸甲酯的胺基羧酸树脂的合成及对Cu~(2+)的吸附性能

以大孔交联聚丙烯酸甲酯为原料,经乙二胺胺解和羧甲基化反应,合成了一种以亲水性聚丙烯酰胺为骨架的胺基羧酸螯合树脂。通过胺解树脂和羧甲基化树脂的交换量测定,推测合成的胺基羧酸树脂是以具有半EDTA型结构的亚胺二乙酸为主要功能基的螯合树脂。测定了该树脂对Cu~(2+)的静态和动态吸附性能,结果表明:该树脂对Cu~(2+)的吸附过程为熵变驱动的自发过程,吸附量可高达2 mmol/g以上,且可用稀硫酸完全脱附,树脂重复使用时对Cu~(2+)的吸附量基本保持不变。测定了该树脂对葛根素水溶液中Cu~(2+)的吸附性能,结果表明:该树脂不仅对葛根素水溶液中Cu~(2+)吸附百分率高达95%,而且对葛根素基本不吸附,说明该树脂可用于某些植物提取物中Cu~(2+)等重金属离子的去除。     

英格兰北部天然水体对Al~(3+)、Fe~(3+)的络合容量

本文采用阳离子交换——滴定法测定了英格兰北部天然水体对Al~(3+)、Fe~(3+)的络合容量。其结果是:在pH5.5条件下,水样对Al~(3+)、Fe~(3+)的络合容量分别为5—13m molAl/gDOC和13—28m molFe/gDOC。络合容量的大小与水样的DOC、色度的趋势一致。水样对Al~3和Fe~(3+)的络合容量之间存在一定的相关性,后者约为前者的2.2倍。     

EDTA快速络合滴定法测定矿石中稀土总量——离子型稀土矿离子相稀土总量测定

本文研究了离子吸附型稀土矿浸出母液中,稀土总量的EDTA快速络合滴定法。提出了以10％磺基水杨酸2.0ml——乙酰丙酮1.0ml的联合掩蔽剂,作为Al~(3+)的掩蔽剂,以二甲酚橙为指示剂,用EDTA标准溶液滴定。这种双掩蔽剂能有效地掩蔽含量高达59mg的铝离子(Al_2O_3)对稀土元素络合滴定的干扰。     

阴极溶出伏安法测定人发中微量硒

本文提出了在(NH_4)_2SO_4—EDTA—Cu~(2+)—Ni~(2+)体系中以阴极溶出伏安法测定人发中微量硒的方法。并对方法的最佳条件选择及头发样品消化处理进行了研究。实验表明:在0.5M(NH_4)_2SO_4-2×10~(-4)MEDTA底液中,加入少量Cu~(2+)-Ni~(2+),可明显改善汞膜电极性能,提高测定灵敏度,结果有较好的重现性。此方法简便,易行,最低检出浓度可达5×10~(-9)M。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with     

Journal of Donghua University ( English Edition) Contents of Volume 31

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Brief Introduction to “Journal of Jilin University( Science Edition) ”

<正>"Journal of Jilin University(Science Edition)"is a comprehensive academic journal in the fields of science sponsored by Jilin University and administrated by the Ministry of Education of the Peoples Republic of China.The journal started publication in 1955.The original name at starting publication was"Journal of Natural Science of Northeast People University",which was changed into"Acta Scientiarum Naturalium Universitatis Jilinensis"in 1958 owing to the name change of the university.The present journal name has