Materials Literature
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The phase-field model is applied to simulate microstructural evolution during isothermal dendritic growth of the δ-phase in undercooled Fe-C liquid. The parameters of phase-field equation are determined by a thin interface limit condition. Realistic dendritic structures at various temperatures and compositions of the…
Regioregular polythiophene copolymers 10a-d containing hexyl and 11-hydroxyundecyl side chains have been synthesised, by nickel-catalysed cross-coupling of well-defined Grignard intermediates. The hydroxy groups were protected during the polymerisation as tetrahydropyranyl ethers, and subsequently transformed into azi…
The structural elucidation of eleven new related polyoxypregnane glycosides, gymnepregosides G (1), H (2), I (3), J (4), K (5), L (6), M (7), N (8), O (9), P (10) and Q (11), from the roots of Gymnema alternifolium (Asclepiadaceae) was achieved by a detailed study of 1H- and 13C-NMR spectral data and chemical means. T…
Two series of novel spiropyrans and spirooxazines having a heteroaromatic pendant were synthesized using two convenient methods.Their photochromic behaviors were investigated with the aid of absorption spectral measurements.The compounds showed several features different from the parent spiro compounds, including an i…
Glasses whose compositions are expressed by the general formula: (50-x/2) BaO. (50-x/2) B 2 O 3 .xTiO 2 with x=4, 8 and 16 have been prepared and the structural modifications occurring in the glass network as consequence of the heat treatments performed near the glass transition temperature and their effect on the dev…
A comprehensive study of the molecule of methanesulfonic acid hydrazide (MSH) is presented. The X-ray structure shows that in the crystal two centrosymmetrically oriented MSH molecules are held together by N–H···N hydrogen bonding interactions. This feature is unprecedented for the known arylsulfonic hydrazide analogu…
A novel manganese vanadium oxide has been synthesized using the hydrothermal reaction of vanadium(V) pentoxide with manganese(II) sulfate with an organic templating cation at 165 °C. The (Mn2+)6(Mn3+)1–2/3z- (OH)3(VO4)3[(VO4)1–2z(V2O7)z] (z = 0.2) phase has a hexagonal tunnel structure and space group P63mc. The cell…
The reaction of ammonia with tris(methylamino)borane B(NHCH 3 ) 3 1 or with a B(NHCH 3 ) 3 derived polyborazine 2 led to completely different processes. Compound 1 reacted spontaneously with NH 3 to give mainly the borazine (CH 3 NH) 3 B 3 N 3 H 3 and subsequently a BN prepolymer which was not processible. A polymer 2…
The behavior of the magnetic components in high frequency switched power supplies depends significantly on the working frequency because of distributed magnetic and electrical field effects. Measurement equipment such as an impedance analyzer usually offers simple equivalent models that allow characterization of the f…
Specular reflectance infrared and electron spin resonance spectroscopies were employed for the analysis of the sites of Li(i), Cu(II) and Cd(II) cations fixed in the structure of montmorillonite from Jelšový Potok (Slovakia) upon heating for 24 h at 300 °C. Li(i) cations are trapped in two different sites: in the prev…
Quasicrystals are metallic alloys, often containing 60 to 70 atomic per cent AI. They typically exhibit crystallographically-forbidden symmetry, such as a fivefold rotational symmetry, illustrated in Fig. 1. Quasicrystals are reasonably abundant in a metallurgical context, since they can be formed by more than 100 com…
A new method for growing silicon crystals by using electromagnetic force to rotate the melt without crucible rotation has been developed. We call it electromagnetic Czochralski (EMCZ) growth. An electromagnetic force in the azimuthal direction is generated in the melt by the interaction between an electric current ( I…
The method for calculation of the mean and local magnetic characteristics of ferromagnetic metals at finite temperatures, developed by the author and co-workers in previous papers and based on using the real band structure and spin fluctuations, is applied to Fe, Co and Ni. The initial parameters of the calculation ar…
Branched tryptophan derivatives were synthesised and their optical properties investigated in a range of solvents: the steady state fluorescent emission from the indole ring sheds light on both the nature of a hydrogen bonding dendritic microenvironment and the optical behaviour of tryptophan residues in biological sy…
Abstract Polyurethane integral skin foams comprise a low density foamed core surrounded by a high density skin of the same material, and are made in a single molding operation. Polyurethane integral skin foams find wide application as structural materials, and the mechanical properties of such foams are significantly…
In this article, the authors report the development of a new low temperature plasma-assisted chemical vapor deposition (PACVD) process for the growth of low resistivity, cubic tantalum nitride (TaNx) for incorporation as a diffusion barrier/adhesion promoter in emerging ultralarge-scale integrated (ULSI) multilevel me…
A new method is shown for lower temperature preparation of tungsten oxide thin film by sol-gel process without using a catalyst, but using tungsten chloride (WCl6) as the starting material and ethanol as a solvent. When WCl6 dissolved in ethanol, tungsten ions and ethanol formed tungsten ethoxides. Thin films prepared…
Oxides with practical applications, such as high T c superconductors, catalysts, solid oxide fuel cells and membranes frequently contain basic cations, which under synthesis or process conditions will be subjected to CO 2 -containing atmospheres and a carbonatization degradation may be initiated. In this paper the con…
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This paper deals with the extruded radially oriented magnets made from rapidly solidified Nd-Fe-B material. The effect of chemical composition on the magnetic properties and hot workability was studied for various compositions in Nd-Fe-Co-Ga-B system. The composition ranges of Nd and B which shows maximum energy produ…