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排序方式: 共有267条查询结果,搜索用时 15 毫秒
251.
Masahiro Ueda Toshihiko Yamaguchi Hiroki Kakiuchi Hiroshi Suga 《Optics and Lasers in Engineering》1999,32(1):21
A simple optical method has been proposed for measuring the vibration amplitude of a speaker vibrating with a frequency of approximately 10 kHz. The method is based on a multiple reflection between a vibrating speaker plane and a mirror parallel to that speaker plane. The multiple reflection can magnify a dispersion of the laser beam caused by the vibration, and easily make a measurement of the amplitude. The measuring sensitivity ranges between sub-microns and 1 mm. A preliminary experiment verified the reliability of this method. 相似文献
252.
The Ru3(CO)12-catalyed cross-coupling reaction of esters with organoboron compounds leading to ketones is described. A wide variety of functional groups can be tolerated under the reaction conditions. Aromatic boronates function as a coupling partner to give aryl ketones. Acyl-alkyl coupling to dialkyl ketones is also achieved by the use of 9-alkyl-9-BBN in place of boronates. The Ru3(CO)12-catalyzed decarbonylative reduction of esters with ammonium formate (HCOONH4) leading to hydrocarbons is also described. No expected aldehydes are produced, and controlled experiments indicate that aldehydes are not intermediate for the transformation. A hydrosilane can also be used as a reducing reagent in place of HCOONH4. A wide variety of functional groups are compatible for both reactions. The key step for both catalytic reactions is the directing group-promoted cleavage of an acyl carbon-oxygen bond in esters, leading to the generation of acyl transition metal alkoxo complexes. 相似文献
253.
Growth of submicrometer-scale rectangular parallelepiped rutile TiO2 films in aqueous TiCl3 solutions under hydrothermal conditions 总被引:7,自引:0,他引:7
Hosono E Fujihara S Kakiuchi K Imai H 《Journal of the American Chemical Society》2004,126(25):7790-7791
Evolution of a new morphology of rutile TiO2 films consisting of nearly single-crystalline parallelepipeds was achieved through hydrothermal treatments of aqueous TiCl3 solutions in the presence of NaCl. 相似文献
254.
255.
Yoshito Tobe Takayuki Iseki Kiyomi Kakiuchi Yoshinobu Odaira 《Tetrahedron letters》1984,25(35):3895-3896
Tricyclic ketones 3a, b and 7a–c having angularly fused 5-6-5 or 5-7-5 ring system have been efficiently prepared by irradiation of bicyclic enones 1 and 2. 相似文献
256.
257.
Tsumoru Morimoto Mana Yamashita Ai Tomiie Hiroki Tanimoto Kiyomi Kakiuchi 《化学:亚洲杂志》2020,15(4):473-477
We describe transfer carbonylation reactions of 2‐bromoarenes that contain a carbon‐nucleophile using aldehydes as a substitute for CO, leading to the formation of indanone derivatives. The transformation proceeds efficiently under RhI/Pd0‐hybrid catalytic conditions consisting of two discrete transition metals, rhodium and palladium, which catalyze the decarbonylation of aldehydes and the subsequent carbonylation of bromoarenes using the resulting carbonyl moiety, respectively. The majority of the abstracted CO is transferred directly to the product via a CO‐relay process from rhodium to palladium. 相似文献
258.
The ruthenium-catalyzed alkenylation of C-H bonds with alkenylboronates has been explored for a series of aromatic ketones. The coupling reaction of pivalophenone (1) with 2-isopropenyl-5,5-dimethyl[1,3,2]dioxaborinane (2) gave the corresponding isopropenylation product in 73% yield. In the case of the reaction of a sterically congested alkenylboronate, such as 2-methylpropenylboronate (8), the yield was decreased slightly. When beta-styrylboronates were used, the corresponding coupling products were obtained in good yields. The reaction of acetophenone with alpha-styrylboronate afforded the corresponding 1:1 coupling product, exclusively. 相似文献
259.
An efficient method for synthesis of E-enamines by the anti-Markovnikov addition of secondary amines to terminal alkynes is described. The reaction of a variety of aryl- and heteroarylacetylenes proceeded at room temperature using a combination of a 8-quinolinolato rhodium complex and P(p-MeOC(6)H(4))(3) as a catalyst. The products were obtained as enamines by simple bulb-to-bulb distillation. 相似文献
260.
Takashi Kakiuchi 《Journal of Solid State Electrochemistry》2011,15(7-8):1661-1671
A salt bridge is a device indispensable in electroanalytical chemistry and has been used over 100?years. Thanks to a salt bridge, we are able to concentrate our attention to what is happening at the working electrode. However, the magical performance of the traditional salt bridge based on potassium chloride does not always work satisfactorily. The longevity of KCl-type salt bridge is mainly because of the lack of better alternatives. A newly emerged salt bridge based on moderately hydrophobic ionic liquids is promising to solve many of the problems that KCl-type salt bridges are unable to, possibly making the future of electroanalytical chemistry a little easier and brighter. 相似文献