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101.
Tomonori Yuasa Ryosuke Honma Hideki Funamizu Izumi Nishidate Yoshihisa Aizu 《Optical Review》2014,21(3):369-372
We are developing a daily health monitoring system that uses mobile phones with cameras and analyzes physiological conditions from R, G, and B intensity levels. However, since it is affected by various imaging conditions of the image input, color correction is required for accurate health monitoring. Therefore, we developed and validated a colorcorrection algorithm to derive reliable color information by correcting the spectral reflectance using the Wiener estimation and a color chart. 相似文献
102.
103.
A simple protocol that uses [OsIII(OH)(H2O)(L ‐N4Me2)](PF6)2 ( 1 ; L ‐N4Me2=N,N′‐dimethyl‐2,11‐diaza[3.3](2,6)pyridinophane) as a catalyst and H2O2 as a terminal oxidant for efficient cis‐1,2‐dihydroxylation of alkenes is presented. Unfunctionalized (or aliphatic) alkenes and alkenes/styrenes containing electron‐withdrawing groups are selectively oxidized to the corresponding vicinal diols in good to excellent yields (46–99 %). In the catalytic reactions, the stoichiometry of alkene:H2O2 is 1:1, and thus the oxidant efficiency is very high. For the dihydroxylation of cyclohexene, the catalytic amount of 1 can be reduced to 0.01 mol % to achieve a very high turnover number of 5500. The active oxidant is identified as the OsV(O)(OH) species ( 2 ), which is formed via the hydroperoxide adduct, an OsIII(OOH) species. The active oxidant 2 is successfully isolated and crystallographically characterized. 相似文献
104.
Atsushi Tarui Shoji Kondo Kazuyuki Sato Masaaki Omote Hideki Minami Yoshihisa Miwa Akira Ando 《Tetrahedron》2013,69(5):1559-1565
A highly diastereoselective cross-coupling reaction of an α-bromo-α-fluoro-β-lactam with a wide range of aryl Grignard reagents was catalyzed by Ni/bis(oxazoline) in yields of up to 98%. The product was obtained diastereoselectively as an anti-isomer. This is the first successful α-arylation of an α-fluoro-β-lactam to produce diverse α-aryl-α-fluoro-β-lactams. 相似文献
105.
Hideki Ishida Hideharu Ishida Makoto Kiso Akira Hasegawa 《Journal of carbohydrate chemistry》2013,32(5):655-664
Abstract α-Stereocontrolled, glycoside synthesis of trimeric sialic acid is described toward a systematic approach to the synthesis of sialoglycoconjugates containing an α-sialyl-(2→8)-α-sialyl-(2→8)-sialic acid unit α-glycosidically linked to O-3 of a galactose residue in their oligosaccharide chains. Glycosylation of 2-(trimethylsilyl)ethyl 6-O-benzoyl-β-d-galactopyranoside (4) or 2-(trimethylsilyl)ethyl 2,3,6,2′,6′-penta-O-benzyl-β-lactoside (5), with methyl [phenyl 5-acetamido-8-O-[5-acetamido-8-O-(5-acetamido-4,7,8,9-tetra-O-acetyl-3,5-dideoxy-d-glycero-α-d-galacto-2-nonulopyranosylono-1”, 9′-lactone)-4,7-di-O-acetyl-3,5-dideoxy-d-glycero-α-d-galacto-2-nonulopyranosylono-1′, 9-lactone]-4,7-di-O-acetyl-3,5-dideoxy-2-thio-d-glycero-d-galacto-2-nonulopyranosid]onate (3), using N-iodosuccinimide-trifluoromethanesulfonic acid as a promoter, gave the corresponding α-glycosides 6 and 8, respectively. The glycosyl donor 3 was prepared from trimeric sialic acid by treatment with Amberlite IR-120 (H+) resin in methanol, O-acetylation, and subsequent replacement of the anomeric acetoxy group with phenylthio. Compounds 6 and 8 were converted into the per-O-acyl derivatives 7 and 9, respectively. 相似文献
106.
Makoto Kiso Hideki Katagiri Hiroyasu Furui Akira Hasegawa 《Journal of carbohydrate chemistry》2013,32(5):627-644
Abstract Suitably protected 1-deoxynojirimycin (l, 5-dideoxy-l, 5-imino-D-glucitol; DNJ) and its 2-acetamido derivative, i.e., 2, 3, 6-tri-O-benzyl-.N-benzyloxycarbonyl-l, 5-dideoxy-1, 5-imino-D-glucitol (6) and 2-acetamido-3, 6-di-O-benzyl-N-benzyloxycarbonyl-1, 2, 5-trideoxy-l, 5-imino-D-glucitol (14) were each coupled with methyl 2, 3, 4, 6-tetra-O-acetyl-1-thio-β-D-galactopyranoside (15) in the presence of dimethyl(methylthio)-sulfonium triflate (DMTST) as a promoter, to give 16 and 18, which were converted to the novel disaccharides (20, 21) related to lactose and lactosamine. Coupling of 14with methyl 3, 4, 6-tri-O-acetyl-2-deoxy-2-phthalimido-l-thio-β-D-glucopyranoside (22) gave achitobiose analog (25). O-(β-D-Galactopyranosyl)-(l→3)-DNJ derivatives (38, 39) and O-(β-D-glucopyranosyl)-(l→3)-DNJ (45) were also synthesized. Conformational analysis of a variety of DNJ derivatives, based on the 1H NMR data, is also discussed. 相似文献
107.
108.
Laser-diode pumped heavy-doped Yb:YAG ceramic lasers 总被引:1,自引:0,他引:1
Laser performance of heavy-doped Yb:YAG ceramics was investigated using a two-pass pumping miniature laser configuration. Slope efficiency of 52% and optical-to-optical efficiency of 48% have been achieved for 1-mm-thick YAG ceramic doped with 20 at.% ytterbium ions. Laser spectra of Yb:YAG ceramic and single-crystal lasers were addressed under different intracavity laser intensities. Heavy-doped Yb:YAG ceramic is more suitable for a thin disk laser than a single-crystal with the same Yb(3+)-ion lasants. 相似文献
109.
Sayoko Nagashima Shota Furukawa Satoshi Kamiguchi Ryu Kajio Hiroshi Nagashima Aritomo Yamaguchi Masayuki Shirai Hideki Kurokawa Teiji Chihara 《Journal of Cluster Science》2014,25(5):1203-1224
A series of molecular rhenium sulfide clusters [Re6S8(OH)6?n (H2O) n ](4?n)? (n = 0, 2, 4, 6) catalyze dehydrogenation of alcohols, and hydrogenation of ketones and olefins in a hydrogen stream at 350 °C. The catalytic activities of the dianionic and neutral clusters (n = 2, 4) are lower than those of tetraanionic and dicationic clusters (n = 0, 6) for all the reactions. When 1,4-butanediol is allowed to react over K4[Re6S8(OH)6], dehydrogenation proceeds to yield 2-hydroxytetrahydrofuran and successively γ-butyrolactone above 300 °C. Over [Re6S8(H2O)6]SO4 dehydration proceeds to yield tetrahydrofuran above 250 °C. The thermal activation mechanisms of these clusters were studied by powder X-ray diffraction analyses, Raman spectrometry, extended X-ray absorption fine structure spectrometry, thermogravimetry, and differential thermal analyses. The catalytically active site of K4[Re6S8(OH)6] is an uncoordinated metal site (Lewis acid site) developed by the loss of a water molecule from two hydroxo ligands. The active site of [Re6S8(H2O)6]SO4 is a Brønsted acid site; the anhydrous aqua cluster dication disproportionates to a hydroxo cluster monocation and a proton. Both of the octahedral cluster frameworks are retained up to 500 °C. 相似文献
110.
Direct Asymmetric Mannich‐Type Reaction of α‐Isocyanoacetates with Ketimines using Cinchona Alkaloid/Copper(II) Catalysts
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Masashi Hayashi Masaru Iwanaga Noriyuki Shiomi Dr. Daisuke Nakane Prof. Dr. Hideki Masuda Prof. Dr. Shuichi Nakamura 《Angewandte Chemie (International ed. in English)》2014,53(32):8411-8415
The enantioselective direct Mannich‐type reaction of ketimines with α‐isocyanoacetates has been developed. Excellent yields and enantioselectivity were observed for the reaction of various ketimines and α‐isocyanoacetates using cinchona alkaloid/Cu(OTf)2 and a base. Both enantiomers of the products could be obtained by using pseudoenantiomeric chiral catalysts. This process offers an efficient route for the synthesis of α,β‐diamino acids. 相似文献