EDTA直滴减量法测定叶绿素铁锌衍生物中锌含量

建立了一种EDTA直接滴定，减量法计算叶绿素铁锌衍生物中锌离子含量的测定方法。研究了测定体系的各影响因素，与实际含锌量比较，相对误差在0．01％～0．1％之间。该法操作简便、快速、无干扰、准确，适用于叶绿素铁锌衍生物生产过程中锌含量的控制。     

短双歧杆菌（Bifidobacterium breve 203）α—D—半乳糖？…

研究发现２５株所试肠道细菌中只有６株双歧杆菌可以利用棉子糖良好生长,并且在棉子糖的诱导下产生α－Ｄ－半乳糖苷酶。９种不同糖中,Ｂｉｆｉｄｏｂａｃｔｅｒ－ｉｕｍｂｒｅｖｅ２０３可以利用葡萄糖,半乳糖、果糖、麦芽、糖乳糖、蜜二糖、棉子糖良好生长,但只有蜜二糖和棉子糖诱导Ｄ半乳糖苷酶的产生。１０ｍｍｏｌ／Ｌdisplay structure     

结合蛋白通常有什么功能?

确定了结合毒物蛋白的位置是在细胞的外膜上,那么在细胞的生活中,这样一种结合蛋白通常有什么作用?由于这种结合蛋白在细胞表面,并可结合α—半乳糖甙类的物质,猜测它通常可能起输送α—半乳糖甙通过细胞膜进入细胞内的作用。用棉子糖(棉子糖是三糖,亦具有α—半乳糖甙键,已如前述)试验,的确看到棉子糖被感病蔗叶的原生质体所吸附,而且结合棉子糖的能力甚至比结合长蠕孢菌甙更快更牢固。用长蠕孢菌甙处理后的感病蔗叶     

蛋粉中蛋白质含量测定方法的比较

用５种方法和２种溶剂对鸡蛋粉中可溶性蛋白质含量进行了测定。结果表明，考马斯亮蓝Ｇ－２５０比色法是一种比较适用的测定方法，溶剂以ＮａＣｌ溶液好于水。     

猪粪中间型耶氏菌的分离和特性

从海南岛昌江县和乐东县的农村家养猪猪粪便中，分离到三株中间型耶氏菌．这些菌株的主要特性是分解多种糖，均能分解鼠李糖、密二糖和棉子糖．     

铅精矿中铅的铅锶共沉淀络合滴定法研究

提出了一个适用铅精矿中铅的测定方法，即矿样以硝酸一氯酸钠溶解，用硝酸锶共沉淀铅，将沉淀溶于热稀硝酸溶液中，在pH值为5．5的六次甲基四胺缓冲液介质中，以二甲酚橙一次甲基为复合指示剂，EDTA滴定铅。     

水体中毒死蜱提取及测定的两种方法比较

比较了水体中毒死蜱两种不同的萃取和测定方法。结果表明,石油醚萃取、紫外分光光度计测定方法简单、快速,适用于大量样品的初期筛选;乙酸乙酯萃取、HPLC(高效液相色谱)测定方法在精确度上高于紫外分光光度法,且能同时检测毒死蜱及其代谢产物TCP(3,5,6-三氯-2-吡啶醇)的含量,但其方法耗时、费力,适用于少量样品的精确测定。紫外分光光度法和HPLC法的最低检测浓度分别为0.1 mg.L-1和0.02 mg.L-1。     

活塞环径向压力分布测量方法分析

分析了内燃机中关键零件活塞环的重要参数径向压力分布的几种测量方法．着重介绍了活塞环径向压力测量的一种新方法——局部薄壁测量法，并从理论上对这种测定方法进行了分析．     

一种估算激光等离子体中气体反应温度的方法

在一些芳香烃的激光等离子体解离产物中存在有丙二烯和丙炔的热异构平衡,本文提出了一种估算激光等离子体化学中气体反应温度的热力学方法.它适用于反应瞬间可建立一种以上化学平衡的反应体系。其准确度取决于平衡体系的本性和反应产物浓度测定方法的准确性.     

维生素E测定方法的研究进展

维生素E结构复杂 ,异构体种类多 ,分析测定困难 ,现存的测定方法之间存在一定的差异 ,亟需找到一种快速、准确、简便的标准测定方法 ,便于实际应用 文中综述了测定维生素E常用的分光光度分析法、荧光分析法、高压液相色谱分析法、双波电压分析法、示波极谱分析法等几种主要方法的原理 ,样品前处理的程序和方法 ,各种方法所能检测到的维生素E异构体种类 ,检测极限、灵敏度 讨论了上述几种测定方法的优缺点 ,适用的样品种类 ,提出了各方法目前仍存在的问题 ,今后的研究方向和重点     

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.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

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.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

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