Materials Literature
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Abstract The modification of the external surface area and the two types of microporosity of palygorskite (structural and interfiber porosity) were examined as a function of the temperature of a vacuum thermal treatment to 500°C. The methods used included: controlled-transformation-rate thermal analysis, N 2 and Ar lo…
The switching characteristics and the electro-optic response due to the electroclinic effect in chiral smectic A liquid crystals are analysed theoretically. We give an exact analytic solution to the dynamic equation of the tilt angle (θ) up to the θ4 term in the Landau expansion of the free energy. The non-linear beha…
High-resolution lattice image observations have been performed for dislocations and deformation twins, introduced by mechanical grinding, in TiO2 and SnO2 crystals with the rutile structure. Dislocations with Burgers vector b = [101] are dissociated into two halves on the (101) plane, while those with b = [001] are no…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSubstrate temperature effects on film chemistry in plasma deposition of organics. I. Nonpolymerizable precursorsGabriel P. Lopez and Buddy D. RatnerCite this: Langmuir 1991, 7, 4, 766–773Publication Date (Print):April 1, 1991Publication History Published online1 May 2002Publ…
Traditionally high electrical stress of insulation occurs in HV equipment. Usually this stress is 50/60 Hz AC and rather seldom DC. Exceptional situations may occur in RF transmitters. This is very different in low voltage equipment. Due to the increased use of high-power semiconductors with high cutoff frequency, wor…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPoly[(aryloxy)carbophosphazenes]: synthesis, properties, and thermal transition behaviorHarry R. Allcock, Suzanne M. Coley, Ian Manners, Oskar Nuyken, and Gerhard RennerCite this: Macromolecules 1991, 24, 8, 2024–2028Publication Date (Print):April 1, 1991Publication History…
New compounds bearing two dihydrogen phosphate groups and two long‐ chain alkyl groups (octyl or decyl) were prepared in good yields by the reaction of 1,ω‐ bis (alkyloxymethyl)‐ oligo (ethylene glycol)s with polyphosphoric acid. Amphipathic di‐ or tetrasodium phosphates were obtained by neutralization of the free aci…
The crystal structures of ribonuclease from Streptomyces aureofaciens (RNase Sa) and its complex with 3'-guanylic acid (guanosine 3'-monophosphate, 3'-GMP) have been determined by the method of isomorphous replacement. The atomic parameters have been refined by restrained least-squares minimization using data in the r…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTReaction between chitosan and cellulose on biodegradable composite film formationJun Hosokawa, Masashi Nishiyama, Kazutoshi Yoshihara, Takamasa Kubo, and Akira TerabeCite this: Ind. Eng. Chem. Res. 1991, 30, 4, 788–792Publication Date (Print):April 1, 1991Publication History…
The relation between crystallinity and the mean free path of high-energy electrons in low-density polyethylene and their effects on dielectric strength was studied. Thin LDPE films obtained by vacuum evaporation were annealed at temperatures between room temperature and 100 degrees C. Crystallinity was measured by X-r…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTUltraviolet-visible and Raman spectroscopy of diatomic manganese isolated in rare-gas matrixesA. D. Kirkwood, K. D. Bier, J. K. Thompson, T. L. Haslett, A. S. Huber, and M. MoskovitsCite this: J. Phys. Chem. 1991, 95, 7, 2644–2652Publication Date (Print):April 1, 1991Publica…
A new copolyester of 3-hydroxybutyrate (3HB) and 3-hydroxypropionate (3HP) was produced by Alcaligenes eutrophus in a nitrogen-free culture solution of 3-hydroxypropionic acid, 1,5-pentanediol, or 1,7-heptanediol. The copolymer composition varied from 0 to 7 mol% 3HP, depending on the type of carbon substrates supplie…
Abstract A new polymer‐forming monomer, 3,4‐bis(4‐aminophenyl)‐2,5‐diphenylpyrrole, was synthesized in three steps starting from 4′‐nitrodeoxybenzoin. Tetraphenylpyrrole‐containing aromatic polyamides and copolyamides were prepared from the diamine with various aromatic diacid chlorides and from a mixture of the diami…
The gas‐solid isotope exchange method using with the continuously recording gravimetric technique was employed for the measurement of the oxygen tracer diffusion coefficient in single‐crystal zirconia. In the temperature range investigated (1300–1600°C) the tetragonal form of the oxide is stable. Both helium and hydro…
A theory has been constructed for the ${\mathrm{CH}}_{3}$F molecule's nuclear-spin conversion induced by the intramolecular magnetic dipole-dipole nuclei interaction. It is shown that for $^{13}\mathrm{CH}_{3}$F molecules this mechanism leads to the rate of spin conversion (0.71\ifmmode\pm\else\textpm\fi{}0.2)\ifmmode…
Abstract Polyurethanes based on methylene bis ( p ‐phenyl isocyanate), bis (hydroxymethyl) propanoic acid, and poly (tetramethylene oxide) were synthesized, and their morphology and physical properties investigated. The acid polyurethanes exhibited very poor phase separation and mechanical properties, but upon neutral…
Ferroelectric thin film compositions in the PLZT system were prepared from water-soluble acetate precursors. Dip coated, multilayer thin films were applied to various substrates, pyrolyzed at 700°C and characterized in regard to dielectric and ferroelectric properties.
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStructure and conformation of poly(ethylene oxide), PEO, in the trigonal form of the PEO-urea complex at 173 KAbdellatif Chenite and Francois BrisseCite this: Macromolecules 1991, 24, 9, 2221–2225Publication Date (Print):April 29, 1991Publication History Published online1 Ma…
The advantage of certain amounts of MgO addition in alumina sintering has been realized, and it is common practice. In an attempt to understand the role of MgO in the presence of CaO in commercial‐grade alumina, grain‐boundary segregation of Ca was investigated by scanning Auger electron microprobe (SAM) using an ultr…
Measurements of the scattering of thermal neutrons from natural samples of molten ZnCl2, ZnBr2, and ZnI2 are reported. The experiments were undertaken on the liquids and amorphous materials diffractometer of the ISIS spallation source at the Rutherford–Appleton laboratory. The data reveal some shortcomings in earlier…