Theoretical and experimental results are presented for the local dynamics of bulk polybutadienes (PB) of various microstructures, i.e., various fractions of cis and trans units. The cooperative kinematics (CK) method is used to analyze the specific mechanism of motion involved in the rotational isomerization of the bonds belonging to the cis and trans units. Correlation times measured by NMR ex...

One long-standing project within lesbian studies has been to develop a satisfactory working definition of "lesbian." This article proposes two new models of a definition using principles of social psychology. Each model (a) utilizes the premise that gender lacks a categorical essence and (b) separates behavioral adherence to cultural stereotypes of femininity and masculinity from one's gender s...

The molecular weight dependence of the radii of gyration Rg in a Θ solvent (trans-decalin) of one regular branched comb and three regular centipede polystyrenes was studied using a gel permeation chromatography system equipped with a two-angle light scattering detector and a refractive index detector. Rg in trans-decalin for each sample of particular molecular weight was about 25% smaller than ...

Abstract: A simple graph-theory-based model is presented, by means of which it is possible to express the energy difference between geometrically non-equivalent forms of a conjugated polyene. This is achieved by modifying the adjacency matrix of the molecular graph, and including into it information on cis/trans constellations. The total π-electron energy thus calculated is in excellent agreeme...

The experimental results of the reaction of C60 with carbonyl ylides generated from trans-epoxides, which afforded cis-products exclusively or predominantly, can be explained well by computational investigation of the proposed reaction mechanism. Our theoretical calculations demonstrate that only cis-carbonyl ylides can be formed directly from trans-epoxides, in compliance with the Woodward-Hof...

This article focuses on developing a novel trans-scale precision positioning stage based on the stick-slip effect. The stick-slip effect is introduced and the rigid kinematics model of the stick-slip driving is established. The forward and return displacement equations of each step of the stick-slip driving are deduced. The relationship of return displacement and the acceleration produced by fr...

Background Smoking is globally the most important risk factor for health and a major factor of mortality. It is responsible for many diseases, such as cardiovascular diseases, digestive system, musculoskeletal system, respiratory system, coronary artery disease, vascular strokes, while destroying the immune system and increases the risk of infections. The aim of this study was to assess the eff...