Materials Literature
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Abstract The dielectric constant, loss tangent and AC conductivity of solution grown cellulose acetate‐butyrate films of 5μm thickness were studied as a function of temperature (300‐450 K) in the frequency range 10 Hz‐10 MHz. The decrease in dielectric constant was observed with the increase in frequency as well as wi…
The reactions of MCl3(M = As or Sb) and 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane (tetramethylcyclam, L) have been studied under controlled hydrolysis conditions as a route to anionic bridging chlorooxo arsenic- or antimony-(III) species. With M = As, the ionic complex [H2L][As4O2Cl10]1 has been isolated…
Abstract Single crystals of beta barium borate and potassium pentaborate (commonly known as β‐BaB 2 O 4 or BBO and KB 5 O 8 . 4 H 2 O or KB5) were grown by high and low temperature solution growth methods, respectively. The dielectric constant and loss tangent were determined as a function of temperature. Frequency re…
Production ball grinding and polishing apparatus were employed as tribometers. The volumetric wear rates of near-net-shape silicon nitride (Si3N4) ceramic ball blanks and the sphericity of the final-polished bearing balls were used to examine the premises that only homogeneous Si3N4 with isotropic structural integrity…
Amphilphilic tetraphenylporphin derivatives having four dialkylglycerophosphocholine groups on the ring plane (lipid-porphyrins) form spherical unilamellar vesicles of diameter ca. 100 nm in water; the vesicles composed of lipid–porphyrinatoiron(II)–1-dodecylimidazole (DIm), can bind dioxygen reversibly in aqueous med…
The reaction between tetraphenylphthalonitrile and phthalonitrile in the presence of copper(I) chloride gives a non-statistical mixture of phthalocyanines from which the tetraphenyl-substituted compound 3 can be isolated.
The CONTAIN computer code is a best-estimate, integrated analysis tool for predicting the physical, chemical, and radiological conditions inside a nuclear reactor containment building following the release of core material from the primary system. CONTAIN is supported primarily by the U. S. Nuclear Regulatory Commissi…
Abstract The temperature-programed desorption (TPD) of hydrogen adsorbed at various temperatures and at nearly saturated coverage has been used to characterize the surface of nickel particles dispersed on silica gel. The TPD spectra have two major peaks, the first and second peaks, at about 375 and 560 K. The second p…
Improvement of the siloxane layer on minerals by using a bisfunctional silane, such as 1,6-bis(trichlorosilyl) hexane and 1,8 bis(trichlorosilyl)octane, and the effects on adhesion of methacrylic resin to glass plates treated with the silanes were studied. The tensile bond strength of the resin to the glass plate trea…
The structural and functional properties of chloroplast glyceraldehyde-3-P-dehydrogenase I (D-Glyceraldehyde-3-phosphate: NADP oxidoreductase (phosphorylating) EC 1.2.1.13) from Spinacia oleracea were investigated by limited proteolysis. The enzyme is insensitive to trypsin and chymotrypsin, while Staphylococcus aureu…
Two experimental techniques—time domain spectroscopy (TDS) and a steady state frequency method—have been used to study dielectric spectra for the isotropic, nematic, SA, SC and SY phases of two thioesters (4-n-pentylphenyl-4′-n-octyloxy-and 4′-n-nonyloxythiobenzoates (C n H2n+1 O‒C6 H4‒COS‒C6H4‒C5H11, where n = 8 and…
The refractive index profiles are investigated for Ag/sup +/-Na/sup +/ ion-exchanged waveguides in soda-lime glass. The waveguides with the highest index change, used to design homogeneous refracting waveguide lenses and prisms, are fabricated at 350 degrees C using concentrated melt with composition of 10 mol.% AgNO/…
Abstract This paper describes a method of removing blurs in scanning electron microscopy (SEM) images caused by the existence of a finite beam size. Although the resolution of electron microscopy images has been dramatically improved by the use of high‐brightness electron guns and low‐aberration electron lenses, it is…
An absorption and a positive circular dichroism (CD) band in the Soret region at 451 nm and a fluorescent emission band at 725 nm provide compelling evidence that the binding of a tentacle tetracationic porphyrin, meso-tetrakis[4-{(3-trimethylaminopropyl)oxy}phenyl]porphine (TθOPP), to calf thymus (CT) DNA leads to ex…
The short-range structure of zirconium hydroxide, an amorphous precursor in the synthesis of zirconia-based ceramics, is considered. New EXAFS data are combined with existing chemical information on this hydroxide to produce a structural model based on two-dimensional linking of tetrameric units involving a combinatio…
The dissolution of nitrogen into molten iron in the temperature range from 1823 to 1923 K has been investigated using an isotope exchange reaction. The feature of this technique is that the chemical reaction rate can be determined without the effect of mass transport in liquid iron. It was experimentally shown that th…
Three polymeric iron(III) complexes [Fe(tdim)Ln]CIO4(L = L11, L2 or L33) consisting of a bridging ligand (tdim = 1,1′-tetramethylenediimidazole) and a quadridentate Schiff base ligand have been prepared and characterized, where H2Ln= RN(CH2)2NR′[R = R′= MeC(OH)CHCMe, n= 1; R = R′=o-HOC6H4CH=,n=3;R = MeC(OH)CHCMe, R′=o…
The structure of mesophases derived from a triptycene subunit substituted with five paraffinic chains has been determined by X-ray diffraction at small angles. They all show a smectic ordering. This is the first example of a smectogen whose rigid core belongs to the D3h symmetry. A hexagonal order has been observed in…
The magnetic field reorientation of an initially aligned sample of a nematic polymer liquid crystal was followed by proton NMR. Evolution to a metastable (banded) state was considered using a Rheo-NMR technique developed previously. Late stage reorientation was studied by taking into account the dynamics of defects fo…
Abstract Strontium tartrate tetrahydrate single crystals doped with nickel have been grown in silica gel. The grown crystals have been characterized by X‐ray, atomic absorption spectroscopy (AAS), thermogravimetric analysis (TGA), and etching technique.