维生素C测定方法的比较研究

通过对２．６－二氯酚靛酚滴定法和紫２外吸收法测定维生素Ｃ的比较研究，发现紫外吸收法抗干扰性强，回收率高，在０－８０μｇ／ｍｌ范围内线性较好，测定过程中较稳定，特别对于有颜色样品更优于滴定法。     

果蔬中维生素C含量测定时不同方法比较

为探索简便适宜的果蔬中维生素C含量测定方法,选取娃娃菜为试验材料,以酸碱滴定法、碘量法、2,6-二氯酚靛酚法和紫外分光光度法测定其维生素C的含量。试验结果表明：酸碱滴定法测定结果显著较高;碘量法操作简单,数据间误差较小,滴定终点容易判断;2,6-二氯酚靛酚法滴定终点不易判断,数据间误差较大;紫外分光光度法数据间误差虽小,但需制作标准曲线且需昂贵的仪器。综合认为开展果蔬中Vc含量测定实验时碘量法为最适宜的测定方法。     

温州薯蓣贮藏期间生理生化指标的变化

对浙江瑞安真薯贮藏期间含水量、电导率和紫外吸收值、褐变度、总酚含量、PPO、POD、SOD活性和MDA含量的变化进行了研究。结果表明：随着贮藏时间的延长,浙江瑞安真薯含水量下降,电导率和紫外吸收值增大,褐变度、总酚含量和MDA含量不断增加,PPO、POD和SOD活性先升后降．     

空气和废气中ClO2测定方法的研究

利用KI，H2O，CCl4作吸收溶剂，采用溶液吸收法采集空气和废气中ClO2，吸收后再用紫外分光光度法或滴定法分析，用KI作为吸收剂，以一定的流量采气，采集30min，其采样效率及加标回收率为94．0％－101．5％，从而找出一种较理想的测定方法。     

氟哌酸及制剂含量测定方法的比较

应用非水溶液滴定法、紫外分光光度法的对照品比较法、吸收系数法、标准曲线法等方法对氟哌酸原料及其片剂、预混剂、水溶性粉剂的合量测定结果进行了比较,同时分析了辅料对制剂含量测定的影响.试验证实氟哌酸原粉在依照中国药典(1990年版)有关规定进行检测的基础上还应辅助紫外分光光度法监测其含量,片剂、预混剂适宜用紫外分光光度法测定含量,水溶性粉剂应采用对照品比较法测定含量.     

几种光产酸剂产酸效率的测定

溴酚兰水溶液的紫外吸收会随着体系中含酸的量发生变化,在440 nm吸收峰处一定浓度范围内溴酚兰水溶液的吸光度与溶液中酸浓度成正比,可由此测定酸浓度.用这种方法测定了3种不同类型的光产酸剂在聚乙二醇膜层中在低压汞灯(254 nm)照射下的产酸量.其中三嗪光产酸剂的光照产酸能力最强.     

杜仲树皮、新鲜叶片和杜仲愈伤组织块有效成分的含量测定

对杜仲树皮（市售）、杜仲新鲜叶片、杜仲幼苗各种愈伤组织块（茎段、幼叶、子房、花药经ＭＳ培养基附加生长调节素培养诱导而得的愈伤组织）的有效成分进行研究，证明它们有一些相同成分。用２，６－二氯酚靛酚滴定法测定了它们维生素Ｃ的含量；用紫外分光光度法测定了它们的桃叶珊瑚甙的含量；用薄层层析－分光光度法测定了它们的氯原酸的含量。     

杜仲树皮,鹇叶片和杜仲愈伤组织块有效成分的含量测定

对杜仲树皮（市售）、杜仲新鲜叶片、杜仲幼苗各种愈伤组织块（茎段、幼叶、子房、花药经ＭＳ培养基附加生长调节素培养诱导而得的愈伤组织）的有效成分进行研究，证明它们有一些相同成分。用２，６－二氯酚靛酚滴定法测定了它们维生素Ｃ的含量；用紫外分光光度法测定了它们的桃叶珊瑚甙的含量；用薄层层析－分光光度法测定了它们的氯原酸的含量。     

对氨基苯甲酸酯类的紫外吸收性能的定量构效关系 Ⅰ.化合物的合成及其PPP法量子化学计算

用亚硫酰氯滴入对氨基(或对二甲氨基)苯甲酸与无水乙醇(或酚)的混合物中,使酰化、酯化一次完成,合成了七个对氨基(对二甲氨基)苯甲酸酯类化合物。用PPP方法对包括上述合成产物在内的十个对氨基苯甲酸及其酯进行了计算,得出了与紫外吸收波长和吸收强度有关的参数,并对其表征吸收强度的参数SOSC进行了修正。     

2.4——二氯酚非水滴定法

2.4——二氯酚(HO—Cl<(?)>—Cl)是合成除草醚及植物生长刺激剂2,4——D的重要原料,用酸碱滴定法测定酚含量,是合成上述农药时配料的重要依据。故用酸碱滴定法测定2,4——二氯酚的含量具有重要意义。一、测定原理:2.4——二氯酚是一种弱有机酸,在水中溶解度甚小,25℃时K_a=3.1×10~(-8).故在水溶液中很难直接滴定。[能在水溶液中滴定的弱酸要求滴定P~H突跃(△P~H)     

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     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the     

An affordable accurate evaluation of the binding conformations predicted by molecular docking studies in bio-system

Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of     

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