Materials Literature
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A double-heteroepitaxial Si/γ-Al2O3/Si structure was realized. An epitaxial (100)Si layer with high quality was successfully grown on a (100)γ-Al2O3/(100)Si substrate by Si2H6 gas-source molecular beam epitaxy at substrate temperatures between 700 and 800 °C. The γ-Al2O3/Si substrate was fabricated by low-pressure che…
We describe the structure and operating characteristics of a high-speed optically addressed spatial light modulator (OASLM) with a hydrogenated amorphous silicon (a-Si:H) photosensor and a ferroelectric liquid-crystal modulator. The photosensor is a p-i-n photodiode, which switches the liquid crystal into one of two s…
The mobility of vacancies and interstitials trapped on a dissociated edge dislocation in copper is studied by molecular dynamics. Although fast diffusion is thought to occur exclusively in a pipe surrounding the dislocation core, in the present study a quasi-two-dimensional diffusion is observed for defects not only i…
Native silicon (Si) oxide growth on Si (100) wafers in air and in ultrapure water at room temperature requires coexistence of water and oxygen in the air and ultrapure water ambients. The growth rate data on n-, n+-, and p+-Si (100) in air indicate layer-by-layer growth of an oxide. The growth rate on n-Si (100) in ul…
We present two simple, but accurate, techniques for calculating the finite-temperature atomic structure and free energy of any solid defect (point or extended). The finite-temperature equilibrium atomic structure and thermodynamic properties of defects in solids are obtained self-consistently by minimizing the rree en…
The effects of hydrogen on the fracture of metals will be reviewed using a selection of observations based on the use of in situ environmental cell experiments. These were developed to allow understanding of the mechanisms of the failure process. The in situ technique, combined with use of the environmental cell, is w…
Development of manganese-stabilized stainless steels has been prompted by two objectives: (1) replacement of nickel, normally used to stabilize austenitic stainless steels, since it is an expensive, strategic material, and (2) reduction of long-term induced radioactivity of neutron-irradiated stainless steels by repla…
Abstract Photoreactive polyimide precursors, which are readily soluble in common organic solvents and optically transparent at light of 365 nm wavelength ( i ‐line), similar to aliphatic polyimide precursors, were obtained by polycondensation of biphenyltetracarboxylic dianhydride (BPDA) and fluorine‐containing diamin…
Abstract Both softwood (spruce) and hardwood (aspen and birch) species in the form of different pulps (e.g., sawdust, chemithermomechanical pulp, explosion pulp and OPCO pulp) have been used (10–40 wt% composite) as reinforcing fillers for thermoplastic composites of polystyrene. Mechanical properties, are examined, e…
Abstract In this study the grafting of acrylamide onto poly(ethylene terephthalate) fibers with the help of benzoyl peroxide and the effects of the temperature and the concentrations of initiator and monomer were investigated. Some of the experiments were repeated several times in order to check the reproducibility. T…
Dispersions of colloidal particles exhibit thermodynamic properties similar to those of molecular systems, including a hard sphere disorder-to-order transition. In experiments with organophilic silica in cyclohexane, gravity settling was used to concentrate the particles. With small particles the slow sedimentation pe…
Article The crystal structures of Ag+Cu2(OH)(SO4)2 ∙ H2O and Me+Cu2(OH)(SeO4)2∙H2O [Me+ = Ag, Tl, NH4], four new representatives of the natrochalcite type, with a note on natural natrochalcite was published on August 1, 1989 in the journal Zeitschrift für Kristallographie - Crystalline Materials (volume 187, issue 1-4…
A soft acoustic mode in a ferroelastic KD3(SeO3)2 crystal have been observed as a function of depth from the surface by the use of a microprobe Brillouin scattering system. Just above the phase transition temperature, the Brillouin frequency shift v, which is related to the hyper sound velocity, becomes hard as the ob…
Free‐energy analyses performed on closed particle‐pore arrays show that the presence of an abnormal grain thermodynamically favors the shrinkage of large pores to which is is adjacent. This gives an explanation to the experimentally observed phenomenon of abnormal‐grain‐growth‐promoted densification in barium titanate.
Abstract Investigations on the temperature variation of specific volume and ultrasonic velocity are carried out to study the phase transitions in the liquid crystals 4′‐n‐Pentyloxy‐4‐Cyanobiphenyl (50CB) and 4′‐n‐Octyloxy‐4‐Cyanobiphenyl (80CB). From these studies various parameters like the adiabatic compressibility…
The products obtained from the roomtemperature reaction of ammonium bifluoride and zirconium fluoride monohydrate are ammonium heptafluorozirconate ((NH 4 ) 3 ZrF 2 ), liquid water, and hydrogen fluoride. Ammonium bifluoride and zirconium fluoride monohydrate were reacted prior to glass batching, producing dry ammoniu…
Visual observation of crystal growth at high pressure was realized by the use of a diamond anvil cell. With a eutectic system of meta- and para-xylenes, phase equilibrium pressures were determined at various compositions and temperatures. Stepwise changes in pressure were applied to drive and observe even rapid growth…
Abstract Demixing / Liquid Crystals / Phase Diagrams / Smectic Phases n‐Heptyloxy‐ and n‐heptylcyanobiphenyl show induced smectic phases in mixtures with n‐alkanes, n‐alcohols, and n‐alkylbenzenes. Alkyloxycyanobiphenyls with shorter alkyl chains (hexyl and pentyl homologues) show miscibility gaps with an upper consol…
The colourless compound RbLiS has been prepared as described earlier (H. Sabrowsky, A. Thimm, and P. Vogt-Mertens, Z. Naturforsch. 40b, 1759 (1985)) and its crystal structure determined by X-ray diffraction. Very hygroscopic RbLiS crystallizes in the tetragonal space group P4/nmm (Z = 2) with the cell parameters a = 4…
The etching mechanism of the interface in plasmas is studied by two complementary spectroscopies, x‐ray photoelectron spectroscopy (XPS) and x‐ray photoelectron diffraction (XPD). Following the removal of the layer, the etching reaction is shown to be rate‐limited by the formation of a highly fluorinated gallium layer…