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排序方式: 共有1371条查询结果,搜索用时 15 毫秒
61.
Hisami Yumoto Shigekazu Onozumi Yoshinori Kato Masatou Ishihara Kiyoshi Kishi 《Crystal Research and Technology》1996,31(2):159-164
Indium tin oxide (ITO) whiskers were grown by VLS (vapour-liquid-solid) mechanism, using the electron shower method. The whiskers were grown above 200 °C, and the deposition rate was above 0.6 nm/s. The electron shower controlled the size of the whiskers, and the size was 30 nm in diameter and 600 nm in length. The whiskers grew along the substrate at t < 300 s, but grew in a direction perpendicular to the substrate at t > 300 s. When the ITO whiskers grown along the substrate were used as NO2 gas sensor, the sensitivity was 340, and about 300 times higher than those of the whiskers grown in a direction perpendicular to the substrate and plate-like ITO crystallites. 相似文献
62.
Yoshinori Tominaga Yoshihide Shiroshita Tomohiko Kurokawa Hiromi Gotou Yoshiro Matsuda Akira Hosomi 《Journal of heterocyclic chemistry》1989,26(2):477-487
The reaction of 1-ethoxycarbonylmethylpyridinium bromides 5a-k with nitro ketene dithioacetal, 1,1-bis-(methylthio)-2-nitroethylene ( 2 ), in the presence of triethylamine in ethanol gave the desired ethyl 2-methyl-thioindolizine-3-carboxylates 3a-k in good yields, along with ethyl 2-methylthio-1-nitroindolizine-3-carboxyl-ates 4a-d . Deesterification of 3 using sodium hydroxide in methanol followed by treatment with polyphosphoric acid gave the corresponding 2-methylthioindolizines 5a-d in good yields. The desulfurization of 5 with Raney-nickel in ethanol occurs smoothly to give the 1,2,3-unsubstituted indolizines 6a-c (a , parent indolizine; b , 8-methylindolzine; c , 6,8-dimethylindolizine). Similarly, pyrrolo[2,1-a]isoquinoline ( 19 ) was also synthesized. These indolizine and pyrrolo[1,2-a]isoquinoline derivatives were allowed to react with dimethyl acetylene to give the corresponding cycl[3.2.2]azine and benzo[g]cycl[3.2.2]azine derivatives in good results. 相似文献
63.
Merieme Ledrhem Miku Nakamura Miyu Obitsu Kinue Hirae Jun Kameyama Hafida Bouamama Chemseddoha Gadhi Yoshinori Katakura 《Molecules (Basel, Switzerland)》2022,27(7)
Cistus L. is a genus of dicotyledonous perennial herbaceous plants. Cistus species have been commonly used in folk medicine in the Mediterranean region. In the present study, the biological activities of essential oils derived from Cistus species (Cistus laurifolius, C. monspeliensis, C. creticus, and C. salviifolius) were evaluated. Essential oils derived from C. laurifolius and C. monspeliensis were found to augment the expression of SIRT1, an anti-aging gene, in the normal culture of HaCaT cells. Furthermore, these essential oils increased the number and size of mitochondria and augmented their activity. These effects were thought to be caused by the up- and downregulated expression of MITOL and Drp1 in HaCaT cells, respectively, in response to the essential oil treatment. In addition, these essential oils were found to attenuate ultraviolet-B-induced mitochondrial damage and cellular senescence in HaCaT cells. These findings indicate that essential oils derived from C. laurifolius and C. monspeliensis may inhibit skin aging through mitochondrial regulation via SIRT1 activation. 相似文献
64.
The carbonylative Stille coupling reaction of benzyl chlorides with allyltributylstannane was successfully conducted by using palladium nanoparticles as the catalyst under phosphine ligand-free conditions. The corresponding α,β-unsaturated ketone products were obtained in good to excellent yields. 相似文献
65.
Tsuda O Ishihara M Koga Y Fujiwara S Setsuhara Y Sato N 《The journal of physical chemistry. B》2005,109(11):4917-4922
Three-dimensional plasma enhanced chemical vapor deposition (CVD) of hydrogenated amorphous carbon (a-C:H) has been demonstrated using a new type high-density volumetric plasma source with multiple low-inductance antenna system. The plasma density in the volume of phi 200 mm x 100 mm is 5.1 x 10(10) cm(-3) within +/-5% in the lateral directions and 5.2 x 10(10)cm(-3) within +/-10% in the axial direction for argon plasma under the pressure of 0.1 Pa and the total power as low as 400 W. The uniformity of the thickness and refractive index is within +/-3.5% and +/-1%, respectively, for the a-C:H films deposited on the substrates placed on the six side walls, the top of the phi 60 mm x 80 mm hexagonal substrate holder in the pure toluene plasma under the pressure is as low as 0.04 Pa, and the total power is as low as 300 W. It is also found that precisely controlled ion bombardment by pulse biasing led to the explicit observation in Raman and IR spectra of the transition from polymer-like structure to diamond-like structure accompanied by dehydrogenation due to ion bombardment. Moreover, it is also concluded that the pulse biasing technique is effective for stress reduction without a significant degradation of hardness. The stress of 0.6 GPa and the hardness of 15 GPa have been obtained for 2.0 microm thick films deposited with the optimized deposition conditions. The films are durable for the tribology test with a high load of 20 N up to more than 20,000 cycles, showing the specific wear rate and the friction coefficient were 1.2 x 10(-7) mm3/Nm and 0.04, respectively. 相似文献
66.
67.
Photolysis of perfluoroazooctane with diamond powders led to chemical modification of the surface with the introduction of perfluorooctyl ester and ether functional groups, the presence of which was confirmed by means of FT-IR, XPS and 19F NMR measurements. 相似文献
68.
Yoshinori SaitoYuriko Takashima Aya KamadaYurika Suzuki Midori SuenagaYasuko Okamoto Yoichi MatsunagaRyo Hanai Takayuki KawaharaXun Gong Motoo Tori Chiaki Kuroda 《Tetrahedron》2012,68(48):10011-10029
Root chemicals and DNA sequences were analyzed for Ligularia virgaurea collected in the northern Sichuan Province and adjacent areas of China. Thirty-eight samples were found to contain five chemotypes, two known and three new ones. From samples of the new chemotypes, 13 new compounds were isolated, including 3 sesquiterpene dimers and some rearranged eremophilanes. The DNA sequences suggested that the chemotype differentiation had a genetic origin. 相似文献
69.
70.