Materials Literature
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A process for production of near‐net‐shape mullite‐matrix ceramic composites at ≤1300°C has been achieved by reaction‐bonding Al 2 O 3 , silicon, mullite seeds, and eutectics of Al 2 O 3 –SiO 2 –mixed‐rare‐earth oxide. The fusion temperature of the eutectic composition utilized is 1175°C. This liquid phase facilitates…
This study demonstrates that the plane-strain Young's moduli E* = E/(1 - v 2) of natural diamonds with a weight of less than 0.2 carat can be determined by the technique of nanoindentation, where E is Young's modulus and v is Poisson's ratio. The indentation test with a Berkovich indenter was conducted at loads of 50,…
TlTaS3 was prepared by applying a sequence of two melting processes with mixtures of Tl2S, Ta, and S having different molar metal to sulphur ratios. TlTaS3 crystallises in space group Pnma with a = 9.228(3)Å, b = 3.5030(6)Å, c = 14.209(3)Å, V = 459.3(2)Å3, Z = 4. The structure is closely related to the NH4CdCl3-type.…
The main dosimetric properties are reported of a new perovskite, LiMgF3, doped with Ce, Er and Dy impurities. An annealing temperature of 400 degrees C for one hour is necessary to erase any previous signal and to stabilise its sensitivity. A readout up to 450 degrees C gives the same result. The glow curve structure…
A thermally stimulated depolarization current (TSDC) study of single crystals of natural fluorine-rich hydroxyapatite, polarized with the electric field (Ep) applied parallel and perpendicular to the c axis, has revealed relaxation modes with axially dependent dielectric behavior. The (re)orientation of the OH− ions i…
The process to fabricate a needle-shaped silicon crystal (silicon needle) has been developed. These silicon needles are fabricated by highly selective anisotropic dry etching, where the etching mask is oxygen precipitation in the silicon substrate. In order to apply these silicon needles to field emitters, the shape o…
This paper reports on the results of precision investigations into the crystal structure of zinc diphosphide and cadmium diphosphide single crystals. The complete sets of fundamental optical functions are calculated for both crystals in the range 2.2–5.3 eV. The dielectric function is resolved into components for the…
Abstract Markers with red luminescence under ultraviolet light were used as tracers for shadowing pursuits in a variety of criminal cases. The luminescent markers consisted of a mixture of 1% europium _-diketonates in Vaseline as the carrier. The visual detection limit under ultraviolet light was 1–100 ppm. Six types…
Vajdakite, a new mineral from Jáchymov, NW Bohemia, Czech Republic, forms minute acicular, gray-green crystals associated with arsenolite, scorodite, parascorodite, kanˇkite, annabergite, köttigite, pyrite, marcasite, nickelskutterudite, and löllingite. Microprobe analysis gave (in wt%): As = 27.72, Mo = 35.39, O = 36…
Dans cette etude nous presenterons les effets de certains parametres tels que la duree d'acquisition et la pression dans la chambre du microscope electronique a balayage environnemental sur les resultats de la microanalyse X. La pression dans la chambre a ete augmentee de 1 Torr (133 Pa) a 15 Torr (1995 Pa). Des mesur…
The four aldol condensation products of methylcyclohexanone isomers and 4-(4-hexyloxybenzoyloxy)benzaldehyde have been prepared. These chiral products were either obtained with high enantiomeric excess or the enantiomers were separated by means of chiral HPLC. In all cases only the E-isomer was obtained. UV irradiatio…
Strained epitaxial bilayers and multilayers consisting of La1−xCaxMnO3 ferromagnetic (FM) layers (x=0.33, 0.4) and La0.33Ca0.67MnO3 antiferromagnetic (AF) layers were grown on (001)LaAlO3 to study the evolution of exchange coupling interactions. The epitaxy was revealed by conventional and high resolution electron mic…
Many-body effects in strongly photoexcited single CdS nanocrystals embedded in Al2O3 matrices have been studied by a scanning near-field optical microscope at low temperatures. Under weak excitations, we find a sharp photoluminescence (PL) band originating from the exciton recombination. With an increase of the excita…
The Korea Atomic Energy Research Institute (KAERI) is manufacturing CaSO4:Dy Teflon TL pellets which have more sensitivity and stability than commercial TLD. A method is presented of preparing the CaSO4:Dy phosphor-embedded Teflon powder, which is then compressed to a thin pellet form used as the TLD element. Investig…
Abstract Triethanolamine (TEA)‐based esterquat has been the primary ingredient in European fabric softeners for several years and is becoming the global molecule of choice. Although it has an excellent environmental profile, TEA esterquat has been plagued by mediocre performance compared to historical molecules such a…
A combined experimental and numerical study of the horizontal Bridgman growth of pure succinonitrile (SCN) has been performed. The effect of convection on interface propagation and shape is quantified and discussed. Measurements were obtained both under conditions of nogrowth and for a 40 µm/s growth rate. The quantit…
The apparent viscosity of alginate impression paste prepared by three mixing methods (hand-mixing technique (HM), semiautomatic instrument (SM) and automatic mixing instrument (AM)), and the gel strength and surface depression of the respective set materials were measured. The materials used were eight commercially av…
In order to obtain comb-like poly-L-lysines bearing a biphenyl mesogen at the end of every repeating unit we have synthesised Nε-4-phenylbenzamido-L-lysine (Kφφ) and the corresponding N-carboxy anydride (Kφφ-NCA). We have homopolymerised the Kφφ-NCA and block-copolymerised it with the NCA of Nε-trifluoroacetyl-L-lysin…
We investigate the geometry and electronic structure of an interstitial H atom in the BaTiO3 crystal considering both cubic and tetragonal crystallographic lattices. A quantum-chemical method based on the Hartree-Fock formalism is used throughout the study. Interstitial H is found to bind to one of the O atoms, formin…
The synthesis and mesomorphic properties of a variety of novel hexasubstituted triphenylene derivatives having three different types of peripheral substitutions are described. Monobromination of 2,3,6,7-tetrakis(pentyloxy)triphenylene 4, prepared by Suzuki coupling of 2-iodo-3′,4,4′,5-tetrakis(pentyloxy)biphenyl 2 and…