Materials Literature
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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…
It is shown that three Frank elastic constants K 1 , K 2 and K 3 of a nematic liquid crystal can be determined by measuring the capacitance change with a magnetic field of a homogeneously aligned cell. The splay elastic constant K 1 is determined from the threshold magnetic field strength H c1 when the magnetic field…
Summary New oil-gelling agents have been developed composed of a long-chain dialkyl phosphate (DP) surfactant and aluminium ion or multinuclear aluminum ion (MAI) which provide good oil-gel systems. One such gelling agent is the aluminum salt of DP (DP-Al) prepared as a precipitate by mixing DP with aluminum chloride…
A new ternary intermetallic compound, Ta 5 Ga 2 Sn, has been synthesized by the self-flux method using molten tin as a solvent. The crystal structure is tetragonal (space group D 4h 18 /I4 mcm). The lattice parameters are a =10.342(2) Å, c =5.174(2) Å, V =555.3 Å 3 , Z =4, and the X-ray density D x is 13.91 Mgm -3 at…
Abstract A first-order phase transition accompanied by a color change from green to black was observed for CsSnI3 at about 425 K. These two modifications showed quite different 127I NQR spectra suggesting drastic structural change. High temperature modification has a perovskite structure with semi-metallic electric co…
Communication: Organic Polyelectrolytes (I–VII) known as Ionenes, with unique combinations of high refractive index (ND) and high Abbe number (VD, see figure) now compete with inorganic glasses for application in optics. Variation of the counterions allows the tuning of their chemical and optical properties.
Abstract The aging of tracers, containing different amounts of Mg, Sr(NO 3 ) 2 , KClO 4 , Al‐Mg alloy and organic binder, was conducted under the conditions of 50.0% and 98.5% relative humidities at 75 °C, and of 98.5% relative humidity at 25 °C. IR spectroscopy and X‐ray diffraction were used for investigation of che…
The properties of intrinsic optical bistability in nematic liquid crystals were studied. This kind of optical bistability is without resonant optical cavity and electric feedback. We find that the nematic ROTN-200 film can exhibit bistability when applying a constant ac electric field (≊560 kHz) that is greater than a…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDevelopment of new adhesion agents for asphalt cementCarlo Giavarini and Gilberto RinaldiCite this: Ind. Eng. Chem. Res. 1989, 28, 8, 1231–1236Publication Date (Print):August 1, 1989Publication History Published online1 May 2002Published inissue 1 August 1989https://pubs.acs…
Gallium is a metal that literally melts in your hand. It has low toxicity, near-zero vapor pressure, and a viscosity similar to water. Despite possessing a surface tension larger than any other liquid (near room temperature), gallium can form nonspherical ...Read More
Abstract Exchgangeable Cl− anions in the interlayer sites of a hydrotalcite-like mineral, Mg6Al2(OH)16Cl2·4H2O, catalyzed a halide-exchange reaction between C6H5CH2Cl and C4H9Br or C4H9I in toluene or in DMF. Thus, for example, a reaction between C6H5CH2Cl (33 mmol) and C4H9Br (195 mmol) in DMF at 343 K for 20 h gave…
The strengths of as‐drawn, abraded, and pristine Se, As 2 Se 3 , As 2 S 3 , and Ge 30 As 15 Se 55 fibers are reported. Pristine strength values range from an average of 80 MPa for Se and Ge 30 As 15 Se 55 to 100 and 180 MPa for As 2 Se 3 and As 2 S 3 , respectively. Although these values are considerably higher than t…
The available data on the effects of fast neutron irradiation on the properties of fine-grain (POCO) graphites at temperatures between 950 and 1400°C are collected. New results are presented for a number of fine-grain graphites irradiated at 600°C. The results are discussed in terms of the useful lifetimes of the grap…