Materials Literature
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CH3OD decomposition has been studied over the stoichiometric, nonpolar (111) and polar, copper‐terminated (100) surfaces of Cu2O. Thermal desorption studies for monolayer coverages of methanol at 90 K show similar conversions, but the product distributions vary significantly, indicating a structure sensitive reaction.…
The analytic formula for the third-order hyperpolarizability γijkl(-3ω;ω,ω,ω) is derived from time-dependent perturbation theory. An approximate formula for γijkl in a static electric field is also presented. The γzzzz values (the chain axis components) for regular polyenes, charged polyenes, donor (D) - acceptor (A)…
Palladium establishes the Pd 2+ –Pd 0 redox equilibrium in a reference alkali borosilicate melt. Most of the palladium exists as the insoluble metal, with only a small fraction of the palladium present as the divalent palladium ion dissolved in the melt. The relative reduction potential of this Pd 2+ –Pd 0 redox coupl…
The Stoner theory of itinerant ferromagnetism was used in calculating the magnetic properties of iron within the self-consistent linear muffin-tin orbital approach. The Stoner exchange parameter, I, was found from the linear-response theory as a function of volume and then adjusted by a constant enhancement factor det…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTFormation of macrocyclic poly(oxymethylene) with narrow molecular weight distribution on the lamellar crystalsMasaki Hasegawa, Kaoru Yamamoto, Toshio Shiwaku, and Takeji HashimotoCite this: Macromolecules 1990, 23, 10, 2629–2636Publication Date (Print):May 1, 1990Publication…
Lead titanate ceramics were successfully made into semiconductors exhibiting anomalous positive temperature coefficients of resistivity (PTCR) about 3 orders of magnitude above the Curie point (480° to 490°C). The PTCR characteristics of the materials prepared were found to be unstable and to show a significant degrad…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTEffect of catalysts on the kinetics of reduction of barite by carbonSatish B. Jagtap, Anita R. Pande, and Ashok N. GokarnCite this: Ind. Eng. Chem. Res. 1990, 29, 5, 795–799Publication Date (Print):May 1, 1990Publication History Published online1 May 2002Published inissue 1…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCytotoxic hydroperoxylepidozenes from the actinia Anthopleura pacifica UchidaGuo Chi Zheng, Akio Ichikawa, Midori O. Ishitsuka, Takenori Kusumi, Hiroshi Yamamoto, and Hiroshi KakisawaCite this: J. Org. Chem. 1990, 55, 11, 3677–3679Publication Date (Print):May 1, 1990Publicat…
X-ray photoelectron spectroscopy (XPS) and high resolution electron energy loss spectroscopy (HREELS) have been used to study the adsorption of polyimide precursor molecules on Ni(110). PMDA (1,2,4,5-benzenetetracarboxylic anhydride) and m-PDA (1,3-phenylenediamine) were vapor deposited in vacuo at substrate temperatu…
Abstract The 1 H-NMR results show that the majority of the isoprene units of butyl rubber are incorporated in 1,4 addition. Approximately 6% of the isoprene units undergo 1,2 enchainment. Based on our study of blends of polyisoprene with polyisobutylene, 1 H-NMR provides an excellent method for determining isoprene un…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAn investigation of the morphology of amorphous/semicrystalline nylon blends using small-angle x-ray scatteringMark E. Myers, Andrew M. Wims, Thomas S. Ellis, and John BarnesCite this: Macromolecules 1990, 23, 10, 2807–2814Publication Date (Print):May 1, 1990Publication Hist…
Abstract The adaptation of the Iosipescu test as a method for determination of the stress and strain to failure and the shear modulus of adhesives under uniform shear conditions is described. The design and performance of a number of special purpose instruments and jigs to facilitate sample preparation, bond line thic…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSinglet oxygen formation in a solid organic polymer upon irradiation of the oxygen-polymer charge-transfer bandPeter R. Ogilby, Marianne Kristiansen, and Roger L. CloughCite this: Macromolecules 1990, 23, 10, 2698–2704Publication Date (Print):May 1, 1990Publication History P…
Chemisorption of polar organic compounds on iron in containing SH − was discussed on the basis of the hard and soft acids and bases principle (HSAB principle). According to the Frumkin isotherm, surface coverages of the compounds and SH − were determined from the double layer capacitances obtained by impedance measure…
Reduction of [OsVI(P)(O)2] (P = porphyrin dianion) with PPh3, ascorbic acid, or N2H4·H2O in the presence of ROH and RSH yielded [OsIV(P)(OR)2] and [OsIV(P)(SR)2], respectively. [OsIV(OEP)Br2] (H2OEP = octaethylporphyrin) was prepared from [OsVI(OEP)(O)2] and Br2. The dialkoxyosmium(IV) and dibromoosmium(IV) porphyrin…
The coercivity Hci of melt-spun Sm-Fe-Ti alloys can be increased to above 4.0 kA/cm by the addition of Zr and Co. Co-substitutions also enhance the remanence Jr and suppress the formation of α-Fe, both of which result in a high-energy product, (BH)max, of up to 56 kJ/m3, the highest value reported so far for 1:12-type…
Amorphous Sm(Fe11Ti) ribbons were prepared by melt spinning. After heat treatment, very fine grains (≊50 nm) of the ThMn12-structure phase were obtained with no signs of a separate intergranular phase. Each grain appears to be a single domain. The maximum room-temperature coercivity is 0.56 T, rising to 1.20 T at 11 K…
Nd15.4Fe77.8B6.8 magnets of various degrees of crystal alignment have been prepared by the conventional powder metallurgy technique. The alignment of these magnets have been determined by x-ray diffraction and fitting the standard deviation of a Gaussian distribution for the relative intensity versus the angle between…
The magnetic behavior of Mn(SCN${)}_{2}$(${\mathrm{CH}}_{3}$OH${)}_{2}$ in single-crystal form has been studied, and the crystal structure has also been determined. The system is monoclinic, C2/c, Z=4 with a=14.467(5) \AA{}, b=5.927(2) \AA{}, c=10.979(3) \AA{}, and \ensuremath{\beta}=93.19(3)\ifmmode^\circ\else\textde…
Abstract For three series of bimodal networks, the stress-relaxation rates and the tearing energies were shown to exhibit maxima at about the same concentrations of short chains as those at which the tensile strengths, reported earlier, also exhibit maxima. These findings clearly show that the reinforcement produced b…