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排序方式: 共有960条查询结果,搜索用时 15 毫秒
911.
Shoichi Okamoto Akira Kawai Kenkichiro Kobayashi Masasuke Takata Tsutomu Yamashita Shiro Yamashita 《Journal of the American Ceramic Society》1983,66(5):78-C-
Boron ions were implanted at room temperature in Ti films at a high dose (7.1 × 10I7 and 2.3 × 1018 ions/cm2 ), The formation of TiB2 films was confirmed by X-ray diffraction. Boron concentration profiles in implanted films were studied by secondary-ion mass spectrometry. 相似文献
912.
913.
Adsorption and anodic oxidation of methanol on palladium electrode in 0·5 N NaOH was studied by measuring current—potential (i-E) and reflectivity—potential (R/R0-E) curves. Presence of methanol retarded the formation of the oxide layer of Pd, giving rise to an anodic shift of the potential. A linear relation was found between the potential retarded and the logarithm of methanol concentration, the slope being about 30 mV/decade. The form of adsorbed entities was discussed based on the slope. The cathodic charge consumed by the reduction of Pd-oxide was smaller in the presence of methanol than in the absence. This was explained by three causes; the less amount of oxide layer formed during the anodic sweep owing to the adsorption of oxidation product of methanol, the reduction of formed oxide layer by a chemical reaction with methanol, and a compensation effect due to the anodic oxidation of methanol during the cathodic sweep. Plottings of the total charge in the anodic region vs — ΔR/R0 in the absence and the presence of methanol suggested that electro-oxidation of methanol proceeds only at the bare portion of Pd. 相似文献
914.
Kozo Tanabe Hideshi Hattori Tsutomu Yamaguchi Susumu Yokoyama Junichi Umematsu Yuzo Sanada 《Fuel》1982,61(4):389-390
The catalytic activity of Fe2O3for the hydrocracking of a bituminous coal at 673K increases when a small amount of SO42? is included in the catalyst. The effect of SO42? is marked in the formation of resins, stronger polar compounds and asphaltenes. 相似文献
915.
916.
917.
Takayuki Shima Yunosuke Makita Shinji Kimura Tsutomu Iida Xiaohua Fang De-sheng Jiang Kazuhiro Kudo Kuniaki Tanaka 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》1996,120(1-4):293-297
Low energy nitrogen (N) ions were irradiated during the epitaxial growth of GaAs using combined ion beam and molecular beam epitaxy (CIBMBE) method as a function of N+ ion acceleration energy (Ea) and N+ ion beam current density (IN). Ea was varied from 70 to 170 eV IN from 900 pA/cm2 to 75 nA/cm2. GaAs growth rate was fixed to 1 μm/h. In 2 K photoluminescence (PL) spectra of the samples with IN = 3 nA/cm2 and Ea = 70–100 eV, two sharp emissions at 1.508 eV (X1) and 1.495 eV (X2), which have been attributed to the emissions of excitons bound to isolated N atoms, and another one at 1.443 eV (X5) were observed. These results show that nitrogen (N) atom in GaAs becomes optically active as an isoelectronic impurity at least in as-grown condition. For N+ ion-irradiated samples with rather high IN, e.g., with IN = 75 nA/cm2 and Ea = 100 eV, a broad emission together with multiple sharp ones were observed after furnace annealing at 750°C which were ascribed to emissions of excitons bound to nitrogen-nitrogen (N---N) pairs. 相似文献
918.
Equations of continuity and motion for dispersed two-phase flow with phase growth are derived and a one-dimensional steady state solution of these equations is obtained for the design and operation of a vertical cone as a continuous crystallizer. This solution is verified by semi-continuous and continuous crystal growth experiments. Cones having divergence angles below about 7° were found to be suitable as continuous classifying crystallizers and an approximate flooding range was found. 相似文献
919.
Let L denote the nonscalar complexity in k(x1,…, xn). We prove . Using this we determine the complexity of single power sums, single elementary symmetric functions, the resultant and the discriminant as root functions, up to order of magnitude. Also we linearly reduce matrix inversion to computing the determinant. 相似文献
920.
Syntheses of dihydrolavandulol and its related compounds from carboxylic acids and conjugated dienes
Tsutomu Fujita Shoji Watanabe Kyoichi Suga Toshiro Miura Kotoji Sugahara Hajime Kikuchi 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1982,32(3):476-484
5-Methyl-2-isopropyl-4-hexenoic acid, dihydrolavandulic acid (III) , was synthesised in 65% yield from 3-methylbutanoic acid and isoprene with sodium naphthalenide in the presence of N,N,N′,N′-tetramethylethylenediamine. Reduction of III with lithium aluminum hydride gave 5-methyl-2-isopropyl-4-hexen-l-ol, dihydrolavandulol ( IV ) (85% yield). Oxidation of IV with pyridinium chlorochromate gave 5-methyl-2-isopropyl-4-hexenal, dihydrolavandulyl aldehyde ( V ) (81 % yield). 相似文献