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1.
由于在反相液相色谱(RPLC)中的分配保留机理忽略了在溶质进入固定相时溶剂分子必须要离开固定相的这一事实,所以,首次得出了RPLC中的分配机理是违背了物理学中的两个基本原理,一个空间不能同时被两个物体占据和能量守恒定律的结论。分配机理不考虑固定相对溶质保留的贡献和惯常置换(吸附)机理不考虑流动相对溶质保留的贡献是不合理的。溶质的计量置换保留模型(SDM—R)不仅符合上述的两个物理学基本原理,而且考虑了RPLC体系中分子间的各种相互作用。用文献中发表的本是用来支持分配机理的原始k’值,着重检验和比较该SDM—R与分配机理的结果,发现这些数据更支持SDM—R。还得出上述结论亦适用于生物大分子。首次证实SDM—R可以用来统一迄今仍在争论的RPLC中的分配机理和置换机理。  相似文献   

2.
色谱学家依据溶质与固定相间相互作用力性质的不同,将色谱分成许多分支。例如,依据色散作用力的反相高效液相色谱(RPLC)、依据氢键和(或者)偶极作用力的正相色谱(NPC)、依据电荷作用力的离子交换色谱(IEC)、根据疏水相互作用力的疏水相互作用色谱(HIC)和依据高选择性生物力的亲合色谱(AFC)等。因此,文献中所报道的不同种类色谱的保留机理也不相同,每一种色谱至少也有一种保留机理。而溶质的计量置换保留模型经检验并证实对上述的各种色谱均适用,并且有着坚实的物理化学基础。但是,到目前为止所报道的SDM—R仅对在置换剂浓度变化不太大的条件下才是准确的。基于计量置换概念,采用了由固定相、溶质及两种置换剂所引起的6个热力学平衡、一个可用于在置换剂全浓度变化范围内的改进的SDM-R表示如下:  相似文献   

3.
反相液相色谱中Z对小分子溶质色谱特征的表征   总被引:1,自引:0,他引:1  
对液相色谱中的一个新的表征参数Z进行了多方面验证。证明Z值在限定条件下可分别作为溶质种类、大小和空间效应及流动相特性的表征,并将Z值与溶质的其他物理化学参数做了相互比较,又以非极性小分子烷基苯的同系物和极性小分子脂肪醇的同系物为例进行说明。  相似文献   

4.
对7种烷基取代酚类化合物在反相高效液相色谱固定相ODS柱,键合-CN基柱上,用甲醇、乙腈,水为流动相体系,选用几种常用的溶质溶剂,考察溶质的色谱保留行为,结合现有的几种键合反相液相色谱保留机理,提出了保留行为模型,对不同的溶质溶剂造成溶质的色谱峰型产生裂分拖尾,前延或不保留等现象给予了较满意的解释。  相似文献   

5.
对7种烷基取代酚类化合物在反相高效液相色谱固定相ODS柱、键合-CN基柱上,用甲醇、乙腈、水为流动相体系,选用几种常用的溶质溶剂,考察溶质的色谱保留行为,结合现有的几种键合反相液相色谱保留机理,提出了保留行为模型,对不同的溶质溶剂造成溶质的色谱峰型产生裂分拖尾、前延或不保留等现象给予了较满意的解释.  相似文献   

6.
目的 建立一个新的描述溶质在二元流动相液相色谱体系中保留的三参数方程并以实验进行验证。方法 通过研究液相色谱体系中溶质分子和溶剂或稀释剂分子的相互作用,得到一个溶质在液相色谱体系中保留的三参数方程,并用不同极性的溶质分子的甲醇-水、乙腈-水和四氢呋喃-水反相色谱体系和极低流动相浓度下的正相色谱体系对此方程进行了验证。结果 在全浓度流动相范围内,实验数据均能用此方程良好描述,且保留方程中的3个参数与所研究的色谱体系的特征紧密相关。结论 所提出三参数溶质保留方程可以用来良好描述二元流动相液相色谱体系中溶质保留的实验结果。  相似文献   

7.
依据质量守恒及固定相表面活性点数目的不变性,推导出溶质在前沿色谱中突破曲线的计量置换模型,并对此模型的性质进行了初步讨论。  相似文献   

8.
应用失次变量nij和nij,非参数统计量Pi、Pi、Si和Dj描述1999年长江上游油菜品种区域试资料。结果表明:9407N丰产性、稳产性最好,94杂-3、黔杂97-2次之。油271丰产性最差,绵阳92-4592稳产性最差。除曲靖、昆明点之外,其余试验点具有较好的代表性。  相似文献   

9.
逆流色谱溶剂体系选择的溶液理论模型   总被引:2,自引:0,他引:2  
从溶液理论出发,建立一个预测和选择逆流色谱溶剂体系的模型,预测了影响分离效果的两相分相情况、两相相比、密度、界面张力等因素,并估算了溶质的分离情况。用文献值和实验值对预测结果进行了检验,结果表明,各参数的预测结果较好,溶质分离情况的估算可指导确定溶质的出峰顺序。  相似文献   

10.
在液—固吸附中计量参数Z及其分量的估算   总被引:1,自引:0,他引:1  
液—固吸附的计量置换模型(SDM—A)中,计量参数Z的物理意义是在吸附(或解吸)过程中,组分Ⅰ分子与吸附剂表面间所释放(或吸附)组分Ⅱ分子的总数。Z值是人们在大分子研究中探索分子构象变化的重要依据。无论是在液—固吸附或色谱研究中,对其分量n和q的计算是非常有价值的,但迄今还未见报道。本文给出一种在研究小分子中机会均等的条件下,即两种组分摩尔数相等时计算参数Z及其分量n和q的方法。在蛋白质高效液相色谱保留机理研究中,溶质计量置换模型(SDM—R)的数学表达式为  相似文献   

11.
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.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
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.  相似文献   

13.
王慧 《科技信息》2008,(10):240-240
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.  相似文献   

14.
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.  相似文献   

15.
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。  相似文献   

16.
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.  相似文献   

17.
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-  相似文献   

18.
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-  相似文献   

19.
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  相似文献   

20.
<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  相似文献   

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