Materials Literature
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A chiral cyclohexane having two photochromic diarylethene unit was synthesized in an attempt to use it as a dopant for a photoresponsive liquid crystal. A stable photoswitching between nematic and cholesteric phases could be induced by the addition of a small amount of the chiral cyclohexane to a nematic liquid crysta…
A polypropylene homopolymer was modified by a rigid filler consisting of three different sizes of CaCO3 particles in various volume fractions. The materials were characterized by differential scanning calorimetry. Mechanical properties of extrusion blended/injection molded samples, including tensile, flexural, Dynatup…
The purpose of this paper is to characterise the anodic oxide films formed on titanium and two ternary titanium alloys, Ti-15Mo-5Al and Ti-10Mo-10Al in 1%, 10% and 20% hydrochloric acid solutions at 25, 50, and 75°C. The anodic film on titanium in hydrochloric acid is stable between + 0.6 V (SCE) and + 2.0 V (SCE). Fo…
A MoSi 2 /reaction‐bonded SiC composite was prepared from a preform of petroleum coke and commercial SiC powders (in weight ratios of 0.5 and 0.6), following reactive infiltration of a Si‐Mo melt (molybdenum concentration of 7–29 wt%) made from elemental powder. The resulting material had a relative density of >90%…
Compounds of the general formula (CH 3 NH 3 ) n-1 (CH 3 C 6 H 4 CH 2 NH 3 ) 2 Pb n X 3n+1 , where X = I, Br, Cl and n= 1,2, 3,..., were prepared and characterized analytically and spectroscopically. Moreover, (CH 3 C 6 H 4 CH 2 NH 3 ) 2 PbX 4 and (CH 3 NH 3 C 6 H 4 CH 2 NH 3 ) 2 Pb 2 I 7 were characterized by X-ray cr…
Spherical particles of silicon dicarbodiimide (SiC2N4, see Figure) are synthesized here via the reaction of tetrachlorosilane (T) and bis (trimethylsilyl)carbodiimide (B) using pyridine as a catalyst and toluene or tetrahydrofuran as solvent. It is shown that the morphology of the thus obtained monodisperse particles…
The structure of samarium disulfide SmS 1.9 , space group P4 2 /n; lattice constants a = 19.717(2)Å ; c = 15.928(1) Å has been determined and refined by LS method to R = 0.0345; R w = 0.0419. The structure is a tenfold superstructure from the structure type ZrSSi. [S2] 2– dumbbells with interatomic distances 2.146(1)Å…
The mesomorphism of hydrogen bonded complexes formed between 4'-carboxybenzo-15-crown-5 stilbazolyl ester (CBCSE) as proton acceptor and carboxylic acids as proton donors is discussed. CBCSE is a monotropic mesogen, forming a nematic phase upon quench cooling. A total of 32 hydrogen bonded complexes has been studied.…
Abstract An analysis of the crystallization kinetics of polytetrafluoroethylene (PTFE) under nonisothermal conditions is presented. A simple method is proposed to remove the limits of the Ozawa theory. The Avramic exponent, n , can be reasonably well determined from the nonisothermal crystallization exotherm. An n val…
Hydrothermally grown crystals of alpha-K3NdSi6O15 x 2H2O, potassium neodymium silicate, have been studied by single-crystal X-ray methods. The compound crystallizes in space group Pbam, contains four formula units per unit cell and has lattice constants a = 16.008 (2), b = 15.004 (2) and c = 7.2794 (7) A, giving a cal…
Effect of sizes and dimensions on the spin density wave (SDW) and charge density wave (CDW) in organic ferromagnets was studied. It was found that the stable ferromagnetic state obtained in a closed ring with periodic boundary conditions would become unstable in an open chain due to the effect of chain ends. There was…
This paper presents a quasiharmonic model for the lattice dynamics of the ${\mathrm{Sn}}_{2}{\mathrm{P}}_{2}{\mathrm{S}}_{6}$ crystal. The model, constructed as a combination of the valence force field and the polarizable ion model with a majority of potential parameters fixed by auxiliary Hartree-Fock calculations, e…
Hydrothermally grown crystals of beta-K3NdSi6O15, potassium neodymium silicate, have been studied by single-crystal X-ray methods. Under appropriate conditions, the compound crystallizes in space group Bb2(1)m and has lattice constants a = 14.370 (2), b = 15.518 (2) and c = 14.265 (2) A. There are 30 atom sites in the…
Slow ramp-type transient-overpower tests were performed within the framework of the international CABRI-2 experimental program. The implemented power transients of ~1% nominal power/s correspond to a control rod withdrawal-type accident in a liquid-metal-cooled fast breeder reactor (FBR). The analysis of the tests inc…
The availability of xylan-type polysaccharides, representing an immense resource of biopolymers for practical application, is summarized. Xylans constitute 25–35% of the dry biomass of woody tissues of dicots and lignified tissues of monocots and occur up to 50% in some tissues of cereal grains. The most potential sou…
In this paper a comparative study of the structure, morphology, and the spectroelectrochemical response of poly (2-ethyl aniline) and polyaniline for different counterions is presented. Spongeous structure of poly (2-ethyl aniline) is obtained when mineral acids are used, while homogeneous and compact films are formed…
Diisopropyl cyclopropane-1,1-dicarboxylate ( 1 ) undergoes ring-opening polymerization in the presence of thiophenolate anions acting as initiator. A carbon-chain polymer, substituted on every third carbon atom by two isopropyl ester substituents, is obtained, whose structure and molecular weight were characterized by…
A theoretical study of light transmission through a polymer with a monolayer ensemble of bipolar nematic droplets under applied electric film is performed. The possibility of interference quenching of monochromatic coherent light directly transmitted through the film is predicted theoretically and realized in the expe…
The effect of annealing with and without applied pressure on the microstructural development and phase transformation was investigated in fine‐grained β‐SiC ceramics containing α‐SiC seeds. Materials annealed without pressure had a microstructure consisting of elongated grains, while materials annealed with pressure s…
The relationship between pore size and air permeability in two spunlaced fabrics and two spunbonded/meltblown/spunbonded (SMS) fabrics were investigated. Minimum, maximum and mean flow pore sizes were determined using liquid porosimetry. The influence of fabric weight and thickness on air permeability and pore sizes w…