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排序方式: 共有196条查询结果,搜索用时 15 毫秒
91.
Yoshiro Kobayashi Toshinori Yamashita Katsuhiro Takahashi Hisashi Kuroda Itsumaro Kumadaki 《Tetrahedron letters》1982,23(3):343-344
Aryltrifluoromethylacetylenes were synthesized by an intramolecular Wittig reaction of trifluoroacetylarylidenephosphoranes, which were synthesized from arylmethyl halides. 相似文献
92.
Toshinori Saito Norio Saheki Minoru Hatanaka Toshiyasu Ishimaru 《Journal of heterocyclic chemistry》1983,20(1):73-75
1,3,4-Thiadiazol-2-ylacetic acids 4 were prepared by lithiation of 2-methyl-1,3,4-thiadiazoles 1 , followed by treatment with carbon dioxide. Diethyl 1,3,4-thiadiazol-2-ylmalonates 6 were prepared by nucleophilic displacement reaction of the corresponding bromides 5 with diethyl malonate. Introduction of the amino group at the a-position of 4 or 6 was carried out via oximation or bromination to give the amino ester 9 or 4 . Attempts to prepare DL-α-amino-1,3,4-thiadiazol-2-ylacetic acids from 9 or 4 were unsuccessful because the amino acids were decarboxylated too rapidly to be isolated in the free form. 相似文献
93.
A photocatalytic membrane reactor for VOC decomposition using Pt-modified titanium oxide porous membranes 总被引:1,自引:0,他引:1
Toshinori Tsuru Takehiro Kan-no Tomohisa Yoshioka Masashi Asaeda 《Journal of membrane science》2006,280(1-2):156-162
Porous titanium oxide membranes with pore sizes in the range of 2.5–22 nm were prepared by a sol–gel procedure, and were applied for decomposition of methanol and ethanol as model volatile organic compounds (VOCs) in a photocatalytic membrane reactor, where oxidation reaction occurs both on the surface and inside the porous TiO2 membrane while reactants are permeating via one-pass flow. Methanol was completely photo-oxidized by black-light irradiation to CO2 when methanol at a concentration of 100 ppm was used at a feed flow rate of 500 × 10−6 m3/min, but the conversion decreased when the MeOH concentration in the feed was increased. Pt-modification was carried out by photo-deposition, and led to a decrease in pore diameter. Using Pt-modified membranes, a nearly complete oxidation of methanol up to 10,000 ppm at a feed flow rate of 500 × 10−6 m3/min was observed. Thus, such membranes would be effective for purifying a permeate stream after one-pass permeation through the TiO2 membranes. The decomposition of ethanol is also discussed. 相似文献
94.
S. Adachi Y. Ogata N. Koshikawa S. Matsumoto K. Kinoshita I. Yoshizaki T. Tsuru H. Miyata M. Takayanagi S. Yoda 《Journal of Crystal Growth》2005,280(3-4):372-377
It is indispensable to estimate a diffusion coefficient in a solution zone in order to grow a homogeneous crystal by using the traveling liquidus-zone (TLZ) method. To estimate the diffusion coefficient of Ge in the SiGe solution zone, result of a two-dimensional numerical simulation is compared with an experimental result. From the comparison, the diffusion coefficient is estimated to be 9.5×10−5 cm2/s. By using this coefficient, a sample translation rate for obtaining a homogeneous SiGe crystal is determined. By translating samples with appropriate rates, homogeneous Si0.5Ge0.5 crystals are successfully grown. The typical Ge composition is 0.496±0.006 for more than 13 mm long. The experimental result shows the homogeneity of ±1.2% in the mole fraction. This deviation corresponds to the variation of less than ±0.03% in the lattice constant. Since this variation is negligibly small, the homogeneity is excellent. Thus it is found that the TLZ method is the universal growth technique, which is applicable to the crystal growth of not only the III–V compounds but also the IV–IV compounds. 相似文献
95.
Takeshi Hoshikawa Xinming Huang Satoshi Uda Toshinori Taishi 《Journal of Crystal Growth》2006,290(2):338-340
Segregation phenomenon of Ga in Czochralski (CZ)–Si crystal growth has been investigated. The effective segregation coefficient, keff, of Ga was obtained for different growth rates by assuming the simple relationship between the concentration of Ga in Si crystal and the bulk Ga concentration in melt. Applying BPS theory to effective segregation coefficients which is valid for the melt-solidified fraction up to 0.38, an equilibrium segregation coefficient of Ga was obtained, k0=0.0079. 相似文献
96.
97.
98.
Optical thin films are used in many optical elements; however, light scattering can be problematic. We investigate the effect of substrate surface roughness on the light scattering of optical thin films. The substrates are classified according to their surface roughness, from fine to very rough, and coated with a single TiO2 layer or a SiO2/TiO2 multilayer. The light scattering intensity increases as the substrate roughness increases. Scanning electron microscopy reveals that the number of nodules formed in the optical thin films increases with the substrate roughness, which affects the light scattering properties. 相似文献
99.
Germanium (Ge) single crystals with an extremely low density of grown-in dislocations were grown by the Czochralski (CZ) technique with boron oxide (B2O3) liquid. Because attachment of particles floating on the melt surface to a growing Ge crystal leads to generation of dislocations during the growth, partial covering of the Ge melt surface with B2O3 liquid was attempted. Such attachment of particles was drastically suppressed or the particles were caught by the introduction of B2O3 liquid, and a particle-free Ge melt was realized in the central region of the melt surface. Ge single crystals were successfully grown from such melt, the grown-in dislocation density being 0–1×103 cm−2, which was remarkably lower than that in Ge crystals grown by a conventional CZ technique. The contaminations by B and O atoms of the grown crystal detected by SIMS analysis were very low. These Ge crystals have the potential for application to be applied as high-quality, dislocation-free substrates of GaAs solar cells for various usages including in space. 相似文献
100.
Tsuyoshi Satoh Takahiro Tsuru Shotaro Ikeda Toshifumi Miyagawa Hitoshi Momochi Tsutomu Kimura 《Tetrahedron》2012,68(4):1071-1084
The addition reactions of α,β-unsaturated carbonyl compounds with dichloromethyl p-tolyl sulfoxide in the presence of NaHMDS or LDA resulted in the formation of adducts, 1-chlorocyclopropyl p-tolyl sulfoxides bearing a carbonyl group at the 2-position, in almost quantitative yields. The carbonyl group of the adducts was transformed to various ether groups to give 1-chlorocyclopropyl p-tolyl sulfoxides bearing an ether functional group at the 2-position in short steps. Treatment of these products with i-PrMgCl at low temperature afforded cyclopropylmagnesium carbenoids via the sulfoxide-magnesium exchange reaction. 1,5-Carbon–hydrogen insertion (1,5-CH insertion) reaction of the generated magnesium carbenoid intermediates took place to give 3-oxabicyclo[3.1.0]hexanes or bicyclo[3.1.0]hexanes bearing an ether group at the 4-position in moderate to good yields. When this procedure was carried out starting with enantiopure dichloromethyl p-tolyl sulfoxide, enantiopure 3-oxabicyclo[3.1.0]hexanes were obtained in good overall yields. These procedures provide a good way for the synthesis, including asymmetric synthesis, of multisubstituted 3-oxabicyclo[3.1.0]hexanes and bicyclo[3.1.0]hexanes from α,β-unsaturated carbonyl compounds and dichloromethyl p-tolyl sulfoxide in short steps. 相似文献