Classification of Kantowski-Sachs and Bianchi Type III Space-Times According to Their Killing Vector Fields in Teleparallel Theory of Gravitation

In this paper we classify Kantowski-Sachs and Bianchi type Ⅲ space-times according to their teleparallel Killing vector fields using direct integration technique. It turns out that the dimension of the telepaxallel Killing vector fields are 4 or 6, which are the same in numbers as in general relativity. In case of 4 the teleparallel Killing vector fields are multiple of the corresponding Killing vector fields in general relativity by some function of t. In the case of 6 Killing vector fields the metric functions become constants and the Killing vector fields in this case are exactly the same as in general relativity. Here we also discuss the Lie algebra in each case.     

Electron-induced scattering dynamics of Boron,Aluminium and Gallium trihalides in the intermediate energy domain

This article is focused on the calculation of electron-induced ionisation and total scattering cross sections by Boron, Aluminium and Gallium trihalide molecules in the intermediate energy domain. The computational formalism, spherical complex optical potential has been employed for the study of these two scattering cross sections. The ionisation cross section has been derived from the inelastic cross section using a semi-empirical method called complex scattering potential-ionisation contribution (CSP-ic) method. We have also calculated the ionisation cross section using the BEB theory with Hartree–Fock and density functional theory (DFT- ωB97XD) orbitals so that a comparison can be made with the cross sections predicted by CSP-ic method. For this theoretical study, we have also calculated polarisability and bond length of some targets which were not found in literature using DFT/B3LYP in Gaussian 09 software.     

Compatibilizing effect of functionalized polystyrene blends: a study of morphology,thermal, and mechanical properties

Polystyrene (PS), being an amorphous polymer is immiscible with other polymers. To engender miscible blends, PS has been functionalized with an active amino‐functional group on the molecular chains of PS to yield amino‐substituted polystyrene (APS), which serves as a reactive compatibilizer. The compatibilization effect of amino functionalized polystyrene on the rubber toughening was explored and results were compared in terms of morphology, thermal, and mechanical properties of PS/SEBS‐g‐MA versus APS/SEBS‐g‐MA blends. In addition, the effect of rubber content on the blend morphology and mechanical properties were investigated. An appreciable change in the thermal stability of APS blends in comparison with PS blend has been probed. A marked correlation has been observed between phase morphology and thermal stability. Use of APS produced the compatibilized blends which render improved blend morphology, enhanced thermal and mechanical properties. Optimal thermal, morphological and mechanical profiles were depicted by 20‐wt% APS blend. Copyright © 2008 John Wiley & Sons, Ltd.     

Butane isomer transport properties of 6FDA–DAM and MFI–6FDA–DAM mixed matrix membranes

For the first time, we report the C4s’ transport properties: solubility, diffusivity, permeability in 6FDA–DAM polymer, one of most permeable glassy polymers with significant nC4 vs. iC4 selectivity. An nC4 permeability of 3.7 Barrer, and nC4/iC4 ideal selectivity of 21 was found in pure 6FDA–DAM polymer membrane. Mixed matrix films were successfully fabricated using a 6FDA–DAM as the matrix, with up to 35 wt% loading of MFI, modified by a two-step Grignard treatment (GT) that produced Mg(OH)₂ whiskers on the surface of the MFI particles. The permeability of nC4 more than doubled; however, the selectivity for the C4s remained the same. Permeation of mixed matrix films with impermeable GT-uncalcined-MFI agree with Maxwell modeling of films with an impermeable solid loading, thereby supporting the existence of a defect-free interface between MFI particles and the polymer matrix. This indicates that the MFI is too permeable to optimally match the properties of the 6FDA–DAM, which is one of the most permeable selective matrix polymers available. It appears unlikely that any currently known, adequately selective glassy polymer can match the high permeability of nC4 in MFI to enable development of promising composite membrane for the C4s separation based on MFI. Therefore a smaller pore size zeolite is required for a better match.     

Synthesis and properties of hyperbranched polyamide-esters derived from 1,3,5-tris(4′-hydroxyphenylcarbamoyl)benzene

A novel aromatic triol was synthesized and polycondensed with various diacid chlorides resulting in the preparation of a series of hydroxy-terminated hyperbranched polyamide-esters without gelation. Structure and degree of branching of the ensuing polymers were confirmed by FTIR, ¹H and ¹³C NMR analyses. These thermally stable polymers were found to be soluble in aprotic solvents. Inherent viscosities and T_g values lie in the range of 0.15-0.21 dL/g and 74-112 °C, respectively.     

Pyrimidine based carboxylic acid terminated aromatic and semiaromatic hyperbranched polyamide-esters: synthesis and characterization

Carboxylic acid terminated aromatic and semiaromatic hyperbranched polyamide-esters (HBPAEs) containing pyrimidine moieties were prepared by polycondensation of 4-hydroxy-2,6-diaminopyrimidine (CBB′) to a double molar ratio of various diacid chlorides (A₂) without any catalyst. The products were soluble in organic solvents, such as N,N-dimethylformamide, N-methyl-2-pyrrolidone and displayed glass transition temperature (T_g) between 180 and 244 °C. The polymerization products have been investigated with FTIR, ¹H and ¹³C NMR analyses and the degree of branching was higher than 60%. Amorphous polymers had inherent viscosity (η_inh) ranging between 0.21-0.28 dL/g and had excellent thermal stability with 10% weight loss at 346-508 °C.     

Theoretical study on dithieno[3,2-b:2′,3′-d]phosphole derivatives: high-efficiency blue-emitting materials with ambipolar semiconductor behavior

Phosphole-based systems due to the unique electronic and optical properties have recently been paid much attention as optoelectronic materials. In this work, the relationship among the electronic structure, charge injection, and transport was investigated for five derivatives of dithieno[3,2-b:2′,3′-d]phosphole (systems 1–5). The structures of systems 1–5 in the ground (S₀) and the lowest singlet excited (S₁) states were optimized at the HF/6-31G* and CIS/6-31G* levels of theory, respectively. Based on these structures, electronic spectra were calculated by time-dependent density functional theory. The simulated emission peaks of five phosphole derivatives locating at the blue–green region (448–516 nm), are in good agreement with the experimental data. Compared with tris-(8-quinolinolate) aluminum (III) (Alq₃), normally used as an excellent electron transporter, systems 1–5 show a significant improvement in electron affinity (EA) due to σ*–π* hyperconjugation, which can effectively promote ability of electron injection. The small differences between λ _h and λ _e for systems 1–5 (0.06–0.14 eV) facilitate charge transfer balance, which suggests systems 1–5 can act as potential ambipolar materials. Owing to good rigidity, low-lying LUMO levels, delocalized frontier molecular orbitals, and the small reorganization energies, the five derivatives of dithieno[3,2-b:2′,3′-d]phosphole are expected to be high-efficiency blue materials in single-layer OLEDs.