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51.
Toshinobu Soma Yutaka Funayama Hiroko-Matsuo Kagaya 《Journal of Materials Science》1990,25(9):3917-3921
The solid solubility of silicon and germanium in aluminium under pressure are investigated using the microscopic electronic theory based on pseudopotentials and using the virtual crystal approximation. Obtained results for the lattice constant and the solid solubility under pressure in the Al-Si and Al-Ge systems are in good agreement with the few available experimental data, in spite of our not introducing any adjustable parameter except for the lattice constant of pure aluminium crystal. The heat of solution and the pressure-volume relation in the Al-Si and Al-Ge systems are presented theoretically. 相似文献
52.
Shin-Ichi Hirano† Toshinobu Yogo† Ko-Ichi Kikuta† Ken-Ichi Noda† Masao Ichida‡ Arao Nakamura‡ 《Journal of the American Ceramic Society》1995,78(11):2956-2960
Crack-free and highly transparent KTiOPO4 (KTP) thin films were synthesized by the sol-gel method using a homogeneous precursor solution prepared from ("BuO)2 -P(O)(OH), Ti(OEt)4 , and KOEt in EtOH. Precipitated powders from the solution crystallized directly to KTP above 550°C. Polycrystalline KTP thin films were obtained at 600°C on various substrates. On NdAlO3 (100) substrates, KTP films with (101) and (240) preferred orientations were formed at 600°C. KTP films on glass substrates showed a refractive index of 1.75 and an absorption edge of 350 nm. KTP films exhibited the second harmonic generation of the 532 nm light on irradiaton with 1064 nm light. 相似文献
53.
Summary End-functionalized poly(isobutyl vinyl ether) (2) with a terminal amine, carboxylic acid, or ester group was prepared by quenching the HI/I2-initiated living polymer ends with ring-substituted anilines (H2N-C6H4-X, p or m; X = NH2, COOH, COOC2H5). The living polymerization of isobutyl vinyl ether and the subsequent end-capping reaction were carried out at –15°C in methylene chloride. The resulting polymers exhibited a narrow molecular weight distribution
and carried one terminal function (aniline residue) per chain, according to 1H NMR structural analysis. 相似文献
54.
Jisun Jin Toshinobu Yoko Fumiaki Miyaji Sumio Sakka Toshiharu Fukunaga Masakatsu Misawa 《Journal of the American Ceramic Society》1993,76(3):630-634
The local structure of a Na2 O─SiO2 oxide glass and a Na2 O─iO2 ─Si3 N4 oxynitride glass has been investigated by the pulsed neutron diffraction method. In the oxide glass, the first peak of radial distribution function (RDF) curves appeared at 0.1627 nm corresponding to Si─O boxh length. In the oxynitride glass, the first peak of the RDF curve was shifted to longer distances at 0.1650 nm due to the coexistence of Si─O and Si─N boxhs. The first peak in the RDF curve of the oxynitride glass was deconvoluted into two peaks whose positions are located at 0.1626 and 0.1709 nm. The one at 0.1626 nm is ascribed to Si─O boxhs and the other at 0.1709 nm to Si─N boxhs. The number of silicon atoms around a nitrogen was found to be 2.42, suggesting that not all of the nitrogen atoms are boxhed to three silicon atoms, but 58% twofold (─N─) and 42% threefold (>N─) nitrogens coexist in the present Na-Si-O-N oxynitride glass. The formation of twofold nitrogens may arise from the reaction between ≡Si─O− and ≡Si3 N groups. This model is compatible with the experimental observation that the density and Vickers hardness of oxynitride glasses increase with the nitrogen content. 相似文献
55.
56.
Summary Living cationic polymerization of isobutyl vinyl ether was achieved by EtAlCl2 in the presence of ethyl acetate at rather high temperatures up to +25°C in toluene. In the absence of the ester additives, neither living nor long-lived propagating species were formed under these conditions. Similarly, living propagating species of vinyl ethers with an ester unit in the pendant (2-vinyloxyethyl benzoate and methacrylate) were obtained with EtAlCl2 alone. The obtained polymers showed a very narrow molecular weight distribution (¯Mw/¯Mn<1.2) and the ¯Mn was directly proportional to the monomer conversion. 相似文献
57.
58.
Pd-Ag thin films were prepared by the RF sputtering method on a Pyrex glass substrate to give monophasic alloys. Oxidation of allylic alcohols using the films gave selectively , -unsaturated carbonyl compounds in the presence of O2; highly dispersed Pd species on Ag, Pd7Ag93 showed 95% selectivity for acrolein from allyl alcohol at 473 K. 相似文献
59.
Summary Vinyl ethers having oxyethylene units [CH2=CHO-(CH2CH2O)-nC2H5, n=1–4] were cleanly polymerized by the HI/I2 initiator in a nonpolar solvent (toluene) at low temperatures (–15 and –40°C) to yield living-like polymers with a very narrow molecular weight distribution (Mw/Mn 1.2); the oxyethylene units in the monomers hardly disturbed the polymerization. The number-average molecular weight of the polymers increased proportionally to monomer conversion and the monomer-to-HI feed ratio. The polymerization rates of the (poly)ether-containing vinyl ethers were much greater than those of alkyl vinyl ethers under similar conditions, and it is presumed that the pendant ether oxygens intramolecularly activate the growing end. The polymers were soluble in methanol (with n1) and in water (with n2), depending on the number of oxyethylene units in the pendant. 相似文献
60.
Summary Living polymerizations of 2-vinyloxyethyl methacrylate and 2-vinyloxyethyl cinnamate were successfully performed with a mixture of hydrogen iodide and iodine (HI/I2) as an initiating system in toluene at –15 to –40 °C, Although the two monomers have an unsaturated ester pendant group, their living polymerizations proceeded exclusively via the vinyloxyl group without undesirable side reactions of the pendant group. The product polymers had a very narrow molecular weight distribution (Mw/Mn 1.1), and {Mn} directly proportional to monomer conversion. For both vinyloxyethyl monomers, the addition of a new feed of monomer to a polymerization mixture led to an increase in polymer molecular weight which was again proportional to the conversion. 相似文献