A simplified expression for the hard-sphere dimer fluid radial distribution function

Recently, in our laboratory a closed form expression for the correlation function of the hard-sphere dimer fluid obtained from Wertheims multidensity Ornstein-Zernike integral equation theory with Percus-Yevick approximation was presented by Kim et al. [2001]. However, it is difficult to apply its expression to perturbation theory and vapor-liquid equilibria calculations, since it is of very complex form. In this work, we present a simplified expression for the first shell of the radial distribution function (RDF) of the hard-sphere dimer fluid using a series expansion of the analytical expression. The expansion is carried out in terms of both the packing fraction and the radial distance. Expressions are also obtained for the coordination number and its first and second derivatives as functions of radial distance and packing fraction. These expressions, which are useful in perturbation theory, are simpler to use than those obtained from the starting equation, while giving good agreement with the original expression results. Then we present an simplified equation of state for the square-well dimer fluid of variable well width (λ) based on Barker-Henderson perturbation theory using its expression for the radial distribution function of the hard-sphere dimer fluid, and test its expression with NVT and Gibbs ensemble Monte Carlo simulation data [Kim et al., 2001].     

Dimeric spectra analysis in Microsoft Excel: a comparative study

The purpose of this work is to introduce the reader to an Add-in implementation, Decom. This implementation provides the whole processing requirements for analysis of dimeric spectra. General linear and nonlinear decomposition algorithms were integrated as an Excel Add-in for easy installation and usage. In this work, the results of several samples investigations were compared to those obtained by Datan.     

Biobased dimer fatty acid containing two pack polyurethane for wood finished coatings

Novel two pack polyurethane wood finished coatings are prepared from renewable sources, such as vegetable oil based fatty acid and dimer fatty acid. In actual experimental part oleic acid was reacted with diethanolamine to obtain amide which was on condensation polymerization with dimer fatty acid converted into the polyesteramide polyol. These are all being used to prepare polyurethanes. The functional and structural elucidation of dimer fatty acid based polyesteramide and diethanolamide were carried out by end group analysis, spectral studies such as FTIR and ¹H NMR. Average molar masses of the polyesteramide were estimated by gel permeation chromatography (GPC). The polyesteramide was used in the preparation of wood finished polyurethane coatings by reacting it with aromatic diisocyanates. Thermogravimetric analysis (TGA) was used to study the thermal behavior of coatings. Physico-chemical and coating properties of the coatings were investigated by using standard methods. The results indicated that the bio-based wood finished PU coatings provided good mechanical, weather resistance as well possessed adequate coating properties for wood surface protections.     

Studies on kinetics and preparation of C36 dimer acid esters

C₃₆ Dimer acids were esterified with various short-chain alcohols, namely 2-propanol, n-butanol, n-hexanol, n-octanol, 2-octanol and 2-ethyl-1-hexanol by using sulfuric acid as catalyst and benzene as an azeotropic solvent. Various reaction parameters were standardized. In case of isopropyl esters, acid-to-alcohol mole ratio of 1:5 and sulfuric acid concentration of 2% based on the weight of dimer acids were found to be optimum. In case of straight-chain primary alcohols, namely n-butanol, n-hexanol and n-octanol, 1:2.5 mole ratio of acid to alcohol and 1% by weight of sulfuric acid were found satisfactory. Esterification reaction rates were determined from the fall in acid value of the product. The reaction followed pseudo first order kinetics. The reaction rates increased with the increase in chainlength of straight-chain primary alcohols from n-butanol to n-octanol. The rate of reaction decreased from n-octanol to 2-ethyl-1-hexanol to 2-octanol due to the branching of the chain in 2-ethyl-1-hexanol and secondary nature of the −OH group in 2-octanol.     

六氟丙烯二聚体及其衍生物

介绍了六氟丙烯二聚体的结构、制造方法，及其各种化学反应和衍生物。并叙述了上述各种反应的催化剂体系和机理分析。     

Microstructures and photovoltaic properties of C60 based solar cells with copper oxides,CuInS2, phthalocyanines,porphyrin, PVK,nanodiamond, germanium and exciton diffusion blocking layers

Abstract

Organic solar cells have a potential for use in lightweight, flexible, inexpensive and large scale solar cells. However, significant improvements of photovoltaic efficiencies are mandatory for use in future solar power plants. One of the improvements is donor–acceptor proximity in the devices, which are called bulk heterojunction solar cells. Bulk heterojunction is an efficient method to generate free charge carriers, and the charge transfer is possible at the semiconductor interface. The purpose of the present work is to fabricate and characterise C₆₀ based solar cells with copper oxides, CuInS₂, phthalocyanines, porphyrin, poly-vinylcarbazole, nanodiamond, germanium and exciton diffusion blocking layers. In the present work, C₆₀ and fullerenol [C₆₀(OH)_10–12] were used for n-type semiconductors, and metal copper oxides, metal phthalocyanine derivative, porphyrin and poly-vinylcarbazole were used for p-type semiconductors. In addition, nanodiamond and germanium based molecules were added into the active layers of the solar cells. The novel aspect of the research is to investigate the relation between properties and microstructures of the solar cells using transmission electron microscopy, X-ray diffraction and electronic structure calculation. The impact of the research concerns the study of organic solar cells by means of microstructural analysis, property measurements and theoretical calculations.     

Dimer acid-based thermoplastic bio-polyamides: Reaction kinetics, properties and structure

New dimer acid-based-polyamides were synthesized with rapeseed oil-based dimer acid (DA) and 1,2-diaminoethane, 1,6-diaminohexane or 1,8-diaminooctane to form DAPAe, DAPAh and DAPAo, respectively. Effects of diamine chain lengths on kinetics evolution as well as on the thermal, physical and mechanical properties of the different polyamides synthesized were investigated. DAPAo was found to be the most reactive diamine because of its higher nucleophilic character. Differential scanning calorimetry (DSC) combined with X-ray diffraction revealed a low-order semi-crystalline structure for all polyamides. A tentative schema for the structural organization of these DAPA is proposed and shows a specific organization with local semi-crystalline segregation domains. DAPAe was found to possess the higher melting temperature likely due to higher crystal cohesion, which was confirmed by higher Young modulus in stress-strain experiments. Rheological data showed an increase of the glass transition temperature concomitantly with the increase of diamine chain length. They also revealed an increase of complex viscosity with the diamine chain length. Investigation of thermal stability showed that DAPAe degrades before DAPAh and DAPAo in connection with the number of methylene units per diamine.     

Isolation and characterization of polymers in heated olestra and an olestra/triglyceride blend

High molecular weight components in thermally oxidized olestra (formerly called sucrose polyesters) and a mixture of olestra and soybean oil were characterized. The high molecular weight components of these oils were separated by preparative size exclusion chromatography and analyzed intact by mass spectrometry, infrared, and nuclear magnetic resonance spectroscopy. The materials isolated from the heated olestra were identified as olestra polymers. Materials isolated from the heated mixed oil (olestra and soybean oil) were identified as polymers of olestra and copolymers of olestra and triglycerides. Polymer linkages identified were identical to those resulting from thermal oxidation of natural vegetable oils of similar fatty acid composition.     

Hydroxy Radical,Hexanal, and Decadienal Generation by Autocatalysts in Autoxidation of Linoleate Alone and with Eleostearate

The formation of hydroxy radicals, hexanal, and 2,4-decadienal was demonstrated from the autocatalytic dimer peroxide which had been reported by us in autoxidizing linoleate (Morita and Tokita in Lipids 41:91-95, 2006). Then, autoxidizing linoleate containing eleostearate was investigated for new autocatalytic substances. The substances obtained were identified as peroxide-linked polymers consisting of both linoleate- and eleostearate-origin units with one hydroperoxy group, and also revealed activity of hydroxy-radical generation. The background of this study is as follows: the above paper reported this autocatalytic dimer peroxide as one of the real radical generators in linoleate autoxidation; this is a peroxide-linked dimer consisting of two linoleate moieties with two hydroperoxy groups, and was much more important than the main-product hydroperoxide in autocatalytic radical supply; its proposed decomposition mechanism has suggested the generation of hydroxy radicals, hexanal, and 2,4-decadienal; on the other hand, analogy to the formation mechanism of this dimer peroxide has predicted the formation of similar polymeric products from conjugated polyene components in lipids. In this study, these two predictions were successfully verified and a discussion is presented in connection with them.     

1,3-ALTERNATE-THIACALIX[4]ARENE-BASED DIMER: SYNTHESIS AND INCLUSION BEHAVIOR

Synthetic approaches to flexible and adaptable thiacalix[4]arene dimer, in which the thiacalix[4]arene units constrain 1,3-alternate conformation, by molecular assembly are presented. The thiacalix[4]arene dimer shows high affinity toward Cs⁺ and K⁺ ions. Encapsulation of Cs⁺ by the internal cavity of the dimer strongly suggests that the size match factor drives the process. On the other hand, the K⁺ is encapsulated by the thiacalix[4]arenes units by supramolecular interaction (cation-π).