Materials Literature
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Several elastic constants of the perovskite-type layer-structure compound (CH 3 NH 3 ) 2 FeCl 4 have been measured. The anomaly of the C 66 mode and the lambda -type heat capacity near the structural phase transition from the tetragonal high-temperature phase to the orthorhombic room-temperature phase gave the critica…
Observations of stable, freely suspended liquid-crystal strands are reported. Liquid crystals of triphenylene hexa-$n$-dodecanoate can be stretched into strands of diameter \ensuremath{\gtrsim}1 \ensuremath{\mu}m, with the disk-shaped molecules arranged into columns along the strand axis. In the $D1$ phase ($T<110\…
The reversible change of oxygen content observed by gravimetric measurements on tantalum (donor)-doped calcium titanate between P02 = 10−16 and 1 atm is proportional to the dopant concentration. These measurements indicate that the tantalum addition is compensated by additional oxygen uptake in the oxidized state. The…
The thermoelectric tensor component S11 and the relative electrical resistance along the binary axis of Bi2Te3 single crystals of p- and n-type are measured under hydrostatic pressure up to 9 GaP and temperatures from 20 to 300 °C. A P-T phase diagram of bismuth telluride is proposed, which is different from diagram,…
A computer simulation study is made on the atomic structure of {1121} twin boundary using a truncated Lennard-Jones potential. It is found that twinned crystals never satisfy the mirror symmetry: in the twin, the alternate basal plane sare displaced by a √3/12 normal to the plane of shear in the opposite direction and…
Thin epitaxial films of CuI have been grown on clean Cu(111) surfaces by chemical reaction with iodine vapor. A lattice match is obtained because the iodine (111) planes of CuI have the same symmetry and approximately the same spacing as the (√3×√3)R30° iodine adsorbate layer which forms initially on exposure of clean…
The vacuum ultraviolet reflectance spectrum of crystalline and vitreous Si${\mathrm{O}}_{2}$ has been measured at low temperature. We find only minor differences between the room-temperature and 5-K spectra of both crystalline and vitreous Si${\mathrm{O}}_{2}$. These observations impose restrictions on the models to e…
We have measured the resistance, magnetoresistance, and nonlinear conductivity in a series of tetramethyltetraselenofulvalinium phosphorus hexafluoride [${(\mathrm{TMTSF})}_{2}$P${\mathrm{F}}_{6}$] crystals which have been damaged with 2.5-MeV protons. For radiation dosages which correspond to \ensuremath{\sim}400-ppm…
Optical absorption and fluorescence spectra of the non-Kramers ions Pr3+, Tb3+, and Ho3+ in the C2 sites of Y2O3 are reported. A crystal-field analysis of these data and previously reported data for Eu3+ and Tm3+ is performed that is based on a Hamiltonian of C2 point-group symmetry, including J-mixing effects. A best…
Abstract The apparent Young's modulus shows a linear relationship with junction density of chitosan films. The linear relationship of apparent Young's modulus with chitosan concentration is also observed. The linear relationship depends of the acid used in the casting solution. Relaxation times were of the order of 10…
Abstract The electro‐optical properties of liquid crystalline polymers with polar mesogenic units in the side chain were investigated. It could be shown, that in an electric field, they show all effects known from low molecular weight liquid crystals, e.g. the Freedericksz‐transition, the DAP‐effect, the formation of…
The complete amino acid sequence of calmodulin from human brain has been determined by using peptides derived from digests with trypsin. Staphylococcus aureus V8 protease, and cyanogen bromide. The peptides were purified by means of reversed-phase high-performance liquid chromatography and analyzed with a sequenator.…
Osteocalcin is an abundant Ca2+-binding protein of bone containing three residues of vitamin K dependent gamma-carboxyglutamic acid (Gla) among its 49 (human, monkey, cow) or 50 (chicken) amino acids. Gla side chains participate directly in the binding of Ca2+ ions and the adsorption of osteocalcin to hydroxylapatite…
A computer program has been developed to analyze the gross structural response of turbine engine fan blades subjected to bird strikes. The program couples a NASTRAN finite element model and modal analysis of a fan blade with a multi-mode bird impact analysis computer program. The impact analysis uses the NASTRAN blade…
The structures of the paraelectric (tetragonal) phase of KH2PO4 (KDP) and 95% deuterated KD2PO4 (DKDP) have been investigated using high-resolution (sin theta bmax/ lambda >1.1 AA-1) single-crystal neutron-diffraction techniques. Full three-dimensional data have been collected at Tc+5K and Tc+ approximately 150K for b…
An experimental study of ionic thermocurrents in doped LiF, NaCl, KBr and KI has been carried out in order to study the dependence of the activation parameters with the ionic radius of the impurity R i . A simple model, which includes lattice distortion around the impurity, has also been developed. This model can expl…
The absolute strengths of the exponential absorption tails of amorphous semiconductors can be correctly predicted from the band-to-band absorption spectra and the exponents of the tails only. This result shows that the tails are due to transitions between band-derived states, and that the mechanism giving rise to thes…
Abstract Observations have been made on medium- and large-sized platelets in a natural type Ia diamond. Attempts have been made to detect any regularity in the structure of the platelets by means of electron diffraction, but none was found. The displacement associated with the platelets has been determined to be extri…
Abstract Most natural diamonds contain nitrogen as the main impurity. In some rare diamonds (termed type lb) the nitrogen is mainly present as single substitutional atoms. However, the large majority of diamonds (termed type Ia) contain the nitrogen atoms in various forms of aggregate. The different types of aggregate…
Abstract The constituent molecules of thermotropic liquid crystals invariably contain an aromatic core to which is attached one and often two n-alkyl chains. Nuclear magnetic resonance investigations have revealed that the chain does not exist entirely in an all-trans configuration and that the orientational order of…