The relationship between the rate–equilibrium coefficient α and transition state properties: a second-order Møller–Plesset perturbation study of SN2 reactions

1992 ◽  
Vol 70 (2) ◽  
pp. 450-455 ◽  
Author(s):  
Zheng Shi ◽  
Russell J. Boyd
Keyword(s):  
Charge Transfer ◽  
Transition State ◽  
Sn2 Reactions ◽  
Leaving Group ◽  
The Difference ◽  
Equilibrium Relationships ◽  
Moller Plesset ◽  
Definition Of ◽  
The Relationship ◽  
Abinitio Calculations

Abinitio calculations including electron correlation are used to study rate–equilibrium relationships in gas-phase SN2 reactions. The difference between the "intrinsic" α and "group" α is emphasized. In general, the "group" α cannot be used as a measure of the transition state structure. The relationships between the "intrinsic" α and other properties, such as reaction endothermicity, geometry change, and the charge transfer, are discussed. A geometry change parameter Rα, defined by analogy with the definition of the "intrinsic" α, is shown to be linearly related to the "intrinsic" α. The charge transfer at the transition state is related not only to energy changes but also to the electronegativities of the entering nucleophile and leaving group in the product and reactant, respectively, and to the electronic structures at the transition state. Thus, the charge transfer parameter Qα, unlike the "intrinsic" α and Rα, is affected by the electronegativities of the groups involved in the reaction. The systems studied are SN2 reactions of the type N− + CH3X → CH3N + X−, where X = H, NH2, OH, OOH, F, CCH, CN, NC, PH2, SH, and Cl when N = H, and where X = H, NH2, OH, F, CN, NC, PH2, SH, and Cl when N = F. Keywords: SN2 reactions, rate–equilibrium relationships, transition state properties.

Charge-Transfer Dipoles at the Si-SiO2 Interface and the Metal-Semiconductor Worfunction Difference In Mos Devices.

1987 ◽  
Vol 105 ◽  
Author(s):  
Hisham Z. Massoud
Keyword(s):  
Dipole Moment ◽  
Charge Transfer ◽  
Dipole Moments ◽  
Silicon Substrates ◽  
Interface Dipole ◽  
Mos Devices ◽  
Flatband Voltage ◽  
The Difference ◽  
Definition Of ◽  
Mos Structures

AbstractThe magnitude of the dipole moment at the Si-SiO2 interface resulting from partial charge transfer that takes place upon the formation of interface bonds has been calculated. The charge transfer occurs because of the difference in electronegativity between silicon atoms and SiO2 molecules which are present across the interface. Results obtained for (100) and (111) silicon substrates indicate that the magnitude of the interface dipole moment is dependent on substrate orientation and the interface chemistry. Dipole moments at the Si-SiO2 and gate-SiO2 interfaces should be included in the definition of the flatband voltage VFB of MOS structures. CV-based measurements of the metal-semiconductor workfunction difference φms on (100) and (111) silicon oxidized in dry oxygen and metallized with Al agree with the predictions of this model. Other types of interface dipoles and their processing dependence are briefly discussed.

scholarly journals LEGAL AXIOMS: APPROACHES TO UNDERSTANDING

2020 ◽  
Vol 1 (9) ◽  
pp. 8-12
Author(s):  
Inna Zelenko ◽  
Keyword(s):  
Legal Regulation ◽  
Complex Phenomenon ◽  
Legal Principles ◽  
Common Features ◽  
The Third ◽  
Legal Science ◽  
The Difference ◽  
Definition Of ◽  
Relationship Of ◽  
The Relationship

The article reflects the diversity of views on the concept of "legal axiom". It is clarified that there are lawyers who deny the existence of the concept of "axiom" in law. It is presented that some scholars identify legal axioms with legal customs in terms of content, formulation and existence, as well as methods of provision. It is revealed that legal axioms have common features and differences with legal presumptions. It is emphasized that the legal presumption and legal axiom are understood as true without evidence. It is considered that the difference between a legal presumption and a legal axiom lies in the difference of circumstances: they allow to consider them plausible; possibilities (impossibilities) of refutation; significance, content and form It is demonstrated that there are several approaches to the relationship of legal axioms with the principles of law. It has been found that the first group of scholars identify the principles of law and axioms. Attention is drawn to the fact that the second group of scholars notes that axioms are prerequisites for the principles of law. It is presented that the representatives of the third group distinguish between the concepts of principles of law and legal axioms. It has been shown that the complex interrelationships of principles and axioms are reflected in their dialectical unity, their ability to pass from one to another, and the disclosure of one phenomenon through another. It is noted that axioms are subject to change, so axioms and presumptions are closely interrelated and under certain conditions can replace each other. The definition of legal axioms has been further considered. Legal axioms are a multifaceted complex phenomenon of legal reality related to law, legal awareness and legal science. regularities, properties of special legal principles of law and serve to simplify legal regulation.

scholarly journals The Relationship Between Biomechanical Indicators of the Snatch Technique and Female Weightlifters' Levels

2015 ◽  
Vol 21 (4) ◽  
pp. 218-222 ◽  
Author(s):  
Paulina Szyszka ◽  
Andrzej Mastalerz
Keyword(s):  
Horizontal Displacement ◽  
Biomechanical Analysis ◽  
Maximum Speed ◽  
World Championship ◽  
Margin Of Error ◽  
The World ◽  
The Difference ◽  
Definition Of ◽  
The Individual ◽  
The Relationship

Abstract Introduction. The snatch technique is a discipline in Olympic weightlifting. The lifter has to raise the barbell from the platform directly above their head in one movement. While reviewing the literature on biomechanical analysis of the techniques of weightlifting, one can find positions on the analysis of parameters, such as barbell track, horizontal displacement, and angular positions of the joints in the individual phases of the lifter's movement. Many texts concern female and male lifters taking part in World or European Championships. The parameters of the best competitors are outlined - mostly those who finish in the top five places in competition. Mostly these are parameters regarding male lifters, and less frequently those of female lifters. In the literature review, an overlooked aspect is that of the definition of the diversity of indicators as regards the snatch technique practiced by female lifters depending on score. Material and methods. In the research, registered snatch attempts during the World Championship were used. Videos were used by judges to establish a maximum weight limit for female lifters. The attempts were registered by two cameras and were later digitally processed by the APAS 2000 system. Barbell parameters, maximum speed, average of the bar, and the parameters of the lifter-bar collocation (horizontal displacement of barbell weights and height elevation) were assessed. Results. The analysed attempts show the margin of error for measurement of the average speed of the barbell as 0.03 m/s. The difference in maximum speed of analysed attempts is 15%. The height of clearance of the first-placed female lifter's barbell was 12.7 cm, 30 cm for the last-placed. Conclusions. The sporting level of weightlifting by female lifters influences the analysed biomechanical indicators of the snatch. Those indicators, which are similar in the case of both the World Championship winner and the female lifter who came last, may be described as the average speeds of the barbell. The high sporting level of female lifters performing heavy lifting is characterized by the clearance of the barbell.

scholarly journals Infographics As a Tool for Improving Effectiveness of Education

2020 ◽  
Author(s):  
Tatyana Bystrova
Keyword(s):  
Participatory Design ◽  
Reference Points ◽  
Cognitive Approach ◽  
Key Points ◽  
On Line ◽  
The Difference ◽  
Online Format ◽  
The Aesthetic ◽  
Definition Of ◽  
The Relationship

This paper defines the criteria of effective infographics for education. Visualizing information, including that with the help of infographics, is one of the mechanisms to optimize the learning process both in traditional and online format. In the first part    of the paper, the author gives a theoretical definition of infographics as a contracted multi-level polysemantic thing. The methodological basis for discussion is provided by the cognitive approach in psyhology and philosophy (R. Arnheim, R. Solso, Y. Valkman) and visual studies (I. Itten, B. Latour, D.  Roem, H. Schiffman). Deriving  the properties of effective infographics, the author seeks to harmonize empirical  data and the results of theoretical studies. The infographic aspects formulated by E.Tafti, Priego, and F. Verbitsky are compared with the results of a survey by L. Harrison on the aesthetic properties of effective infographics. Features of infographics such as scalability, structure-based, focusing on the key points, visual simplicity, and emphasis on the relationship between elements, are by author defined. The difference between infographics and other graphical products is demonstrated. For education it is particularly important that the logic of a structure or image ensures the contraction of information. In turn, the contracted information looks compact and concise. ”Real” infographics have a visual clarity, presence of composition, colour, and image-bearing reference points. Systematic manner enhances the process of developing additional meanings. Aesthetics of the designer‘s infographics represent the reverse side of expediency and logic of a project decision. Th3e article concludes with a discussion of the need to use a cognitive approach to infographics by designers who create effective educational products. Keywords: design, graphic design, infographics, definition of infographics, infographics for the on-line course, participatory design, survey

What Is So Special About Jus Cogens? – On the Difference between the Ordinary and the Peremptory International Law

2012 ◽  
Vol 14 (1) ◽  
pp. 3-18 ◽  
Author(s):  
Ulf Linderfalk
Keyword(s):  
International Law ◽  
General Definition ◽  
Vienna Convention ◽  
Present Essay ◽  
The Creation ◽  
The Difference ◽  
Definition Of ◽  
Jus Cogens ◽  
The Relationship ◽  
Legal Consequences

Abstract What, exactly, is it about jus cogens that distinguishes it from ordinary international law? In answering this question, international lawyers usually resort to the “the Legal-Consequences-as-Criterion Theory”: while ordinary international law can be rebutted or modified in accordance with the duly expressed will of states, jus cogens norms permit no derogation and allow modification only by the creation of a new norm having the same character. In the present essay, this theory is subjected to analysis and assessment. Section 2 inquires into the relationship between the Legal-Consequences-as-Criterion Theory and the general definition of jus cogens reflected in Article 53 of the 1969 Vienna Convention. As argued, Article 53 is entirely reliant upon the validity of the Legal-Consequences-as-Criterion Theory. Sections 3 and 4 inquire into the assumptions underlying this same Theory. As argued, the Theory does not provide good reasons for the distinction between jus cogens and ordinary international law.

scholarly journals Studies of Nutrients Speciation in the Solid Substrate Polystyrene Nutrients Anchored Material Using pH-Metric Method

2019 ◽  
pp. 413-422
Author(s):  
Kiriro G. Nduta ◽  
Isaac W. Mwangi ◽  
Ruth W. Wanjau ◽  
Jane I. Murungi ◽  
Paul K Mbugua ◽  
...  
Keyword(s):  
Transition State ◽  
Solid Substrate ◽  
Water Mixture ◽  
Fixed Amount ◽  
Relative Growth ◽  
Ph Variation ◽  
Aas Method ◽  
Nutrients Concentration ◽  
The Difference ◽  
The Relationship

Studies of relationship between pH variation and the nutrients distribution in the substrate/water mixture provides information about the concentration of the nutrients anchored in the substrate and the efficiency in which they are availed and controlled for plant relative growth. The technique for determining this relationship was based on measurement of changes in peak current (ip) by DPASV method, following different concentration of HNO3 added to a fixed amount of solid substrate polystyrene nutrients anchored material (M+). The total nutrients in the substrate residual (MLn-1) after several stripping experiments is determined by AAS method, the difference between the initial total nutrients concentration before stripping (MLn) and (M+ + MLn-1), gives the concentration of the nutrients in the transition state. The method is advantageous in that the relationship can be measured under conditions where nutrients in the solution controlled directly the current. The results were then modeled so as to make an estimation of the availability of plants nutrients anchored in the substrate. The results shows that at pH 5.5, 5.02×10-1µmol l-1of the nutrients had solubilized, 3.98×10-1µmol l-1was complexed and 15.23×10-1µmol l-1was in the transition state. This balance is enough to support plant growth without chemical burn.

Effect of the structure of phosphylating agents on their reaction with ethanolamine, an ambident nucleophile

1970 ◽  
Vol 48 (9) ◽  
pp. 1351-1357 ◽  
Author(s):  
R. Greenhalgh ◽  
R. M. Heggie ◽  
M. A. Weinberger
Keyword(s):  
Activation Energy ◽  
Charge Transfer ◽  
Transition State ◽  
Ionization Potential ◽  
Bond Formation ◽  
Dominant Factor ◽  
Wide Range ◽  
Leaving Group ◽  
Ambident Nucleophile

The reactions of a series of phosphylating agents (RR′P(O)X) with ethanolamine have been examined, and relative yields of the products from the nucleophilic amino and hydroxyl moieties determined. In general the amount of O-phosphylation increased as R and R′ were changed from dimethylamino through alkoxy to methyl and as the leaving group (X) was changed from OP(O)RR′ to CN. The only exceptions occurred when R was dimethylamino and X was Cl. When X was F, only O-phosphylation was observed. Thus, a wide range of essentially continuously varying selectivities was found.The results are discussed in terms of the amount of charge transfer involved in the formation of the transition state which is assumed to be determined by the electrophile. When the charge transfer is small, the contributions to the activation energy of such factors as solvation and ionization potential of the nucleophile are most important, resulting in N-phosphylation. As the amount of charge transfer increases, the energy of bond formation becomes the dominant factor and O-phosphylation is preferred.

Power, Labor, and the Dynamics of Change in Chacoan Political Economy

1997 ◽  
Vol 62 (1) ◽  
pp. 7-26 ◽  
Author(s):  
Dean J. Saitta
Keyword(s):  
Political Economy ◽  
Social Life ◽  
Social Power ◽  
Surplus Labor ◽  
Change Dynamics ◽  
Middle Range ◽  
The Difference ◽  
Definition Of ◽  
The Relationship ◽  
Human Social Life

The organizational structure of the famous Chaco Phenomenon has long been debated by southwestern archaeologists. To better clarify the nature and dynamics of Chacoan organization we need to rethink the relationship between social power and the appropriation of surplus labor in middle-range societies. Drawing on the tradition of anthropological political economy, I outline a theoretical approach that allows for the relative autonomy of power and labor relations in human social life and models Chacoan political economy using a “thin definition” of communalism. Empirical patterns from the Chaco and post-Chaco eras in the northern Southwest are presented in support of a model of Chaco communalism and change dynamics. Suggestions for furthering a political economy of the Chaco Phenomenon that respects the difference or “otherness” of the past are also detailed.

scholarly journals Rights, Commons, and Social Capital: The Role of Cooperation in an Italian Agri-Food Supply Chain

2021 ◽  
Vol 13 (21) ◽  
pp. 12161
Author(s):  
Enrico Giovannetti ◽  
Paola Bertolini ◽  
Margherita Russo
Keyword(s):  
Social Capital ◽  
Supply Chain ◽  
Field Research ◽  
Units Of Analysis ◽  
The Difference ◽  
Definition Of ◽  
The Relationship ◽  
Parmigiano Reggiano ◽  
Natural Laboratory

The paper discusses the relationship between Commons, Social Capital, and sustainability in terms of resources used, tools available, and goals to be achieved. The conceptual framework differs from the traditional one, which considers Commons and Social Capital as different resources. The paper considers Commons and Social Capital as homogeneous assets defined by the rights related to the access, use, and reproduction of collective resources, material or immaterial, which are essential to reduce the difference between private and social costs in the economic processes. This approach derives from a definition of sustainability as a private and social responsibility in reproducing all the resources used in the life processes, minimizing the waste caused by their exhaustion and loss of fertility. The paper refers to the model of Commons by the school of Elinor Ostrom to explain the nature and role of Social Capital and to observe it in different units of analysis, with particular attention to the forms of cooperative enterprise. The last part of the work outlines field research on the Parmigiano Reggiano supply chain as a natural laboratory to test the theoretical hypotheses.

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