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排序方式: 共有474条查询结果,搜索用时 15 毫秒
101.
Six new dibenzofuran glycosides, fortuneanosides G (1), H (2), I (3), J (4), K (5), and L (6), were isolated from the fruit of Pyracantha fortuneana (MAXIM) LI. Their structures were determined to be 3,7-dihydroxy-2,4-dimethoxy-dibenzofuran 7-O-beta-D-glucopyranoside, 3,7-dihydroxy-2,4-dimethoxy-dibenzofuran 7-O-(alpha-L-rhamnopyranosyl)-(1-6)-beta-D-glucopyranoside, 3,6-dihydroxy-2,4-dimethoxy-dibenzofuran 6-O-beta-D-glucopyranoside, 2,4-dimethoxy-3,6,9-trihydroxy-dibenzofuran 6-O-beta-D-glucopyranoside, 3,9-dihydroxy-2,4-dimethoxy-dibenzofuran 3-O-beta-D-glucopyranoside, and 2-methoxy-3,4,9-trihydroxy-dibenzofuran 4-O-beta-D-glucopyranoside based on spectroscopic analysis. Fortuneanosides G-J showed more potent tyrosinase-inhibitory activity than arbutin. 相似文献
102.
This Letter describes an efficient method—one that takes advantage of hydrogen bond-guided self-assembly and ruthenium-catalysed propargylic substitution—for the preparation of rotaxanes. The substitution reactions of a pseudorotaxane with a diverse range of heteroatom- and carbon-atom-centred nucleophiles were catalysed by the [(Cp∗)RuCl(SMe)]2 complex to furnish rotaxanes in good yields. 相似文献
103.
Yasuaki Shinohara Humiyuki FujimoriTomohiro Suzuki Mitsunobu Kurihara 《Journal of Computational and Applied Mathematics》2007
In this paper, a boundary value problem for delay differential equations of population dynamics is considered. We obtain approximate solutions by using Chebyshev polynomial series and Newton–Raphson's procedure and give the error estimation. The method of the error estimation has been obtained in an existence theorem proved by a part of the authors. We carry out some numerical experiments by a computer language MATLAB. 相似文献
104.
Stuart D Breedon RE Chinitz LM Ko W Lander RL Rowe J Smith JR Kirk P Cheng CP Gao WX Yan WG Ye MH Abashian A Gotow K Haim D Mattson ME Morgan N Piilonen L Sterner KL Lusin S Rosenfeld C Wang AT Wilson S Zheng LY Fry CA Tanaka R Abe K Fujii Y Kurihara Y Liu F Maki A Nozaki T Omori T Sagawa H Sakai Y Sasaki T Sugimoto Y Takaiwa Y Terada S Walker R Kanda S Olsen SL Ueno K Kajino F Poling R Thomas T Aso T Miyano K Miyata H Oyoshi M Yamashita Y Lee MH Sannes F Schnetzer S Stone R Vinson J Bodek A 《Physical review D: Particles and fields》1994,49(7):3098-3105
105.
Liu F Chinitz LM Abe K Breedon RE Fujii Y Kurihara Y Maki A Nozaki T Omori T Sagawa H Sakai Y Sasaki T Sugimoto Y Takaiwa Y Terada S Kirk P Cheng CP Gao WX Yan WG Ye MH Abashian A Gotow K Mattson ME Piilonen L Sterner KL Lusin S Rosenfeld C Wilson S Zheng LY Fry CA Tanaka R Ko W Lander RL Rowe J Smith JR Stuart D Kanda S Olsen SL Ueno K Kajino F Poling R Thomas T Aso T Miyano K Miyata H Okubo K Oyoshi M Shirai M Yamashita Y Lee MH Sannes F Schnetzer S Stone R Vinson J Bodek A Kim BJ Kumita T 《Physical review D: Particles and fields》1994,49(9):4339-4347
106.
n-type organic field-effect transistors with very high electron mobility based on thiazole oligomers with trifluoromethylphenyl groups 总被引:1,自引:0,他引:1
Ando S Murakami R Nishida J Tada H Inoue Y Tokito S Yamashita Y 《Journal of the American Chemical Society》2005,127(43):14996-14997
Novel thiazole oligomers and thiazole/thiophene co-oligomers with trifluoromethylphenyl groups were developed as n-type semiconductors for OFETs. They showed excellent n-type performances with high electron mobilities. A 5,5'-bithiazole with trifluoromethylphenyl groups forms a closely packed two-dimensional columnar structure leading to a high performance n-type FET. The electron mobility was enhanced to 1.83 cm2/Vs on the OTS-treated substrate. 相似文献
107.
R. Seki M. Watanabe K. Kurihara 《Journal of Radioanalytical and Nuclear Chemistry》2000,243(2):383-386
The amount of long-lived radioiodine, 129I (half-life 1.57·107 y) in the Japanese environment has been studied by measuring thyroids of humans and animals. The collected samples were thyroids of (1) humans in Ibaraki Prefecture, in Kanto district, the central part of Japan, (2) cattle in Aomori Prefecture, north part of Japan, and (3) wild deer in Chiba Prefecture, in Kanto district. The measured mean isotopic ratio 129I/127I for thyroids of cattle in Aomori Prefecture is 3.5±1.8·10-9. A higher value of 14±5·10-9 has been obtained for thyroids of wild deer in Kanto district. On the other hand, the measured ratio for human thyroids in Kanto district is 1±0.2·10-9. This value is significantly lower than that of cattle thyroids in Aomori and also those reported for human thyroids in Europe and USA. The higher mean ratio for cattle thyroid in Kanto district is possibly explained by the influence of nuclear reprocessing plant. Lower mean ratio for human thyroid might be due to higher dietary intake of algae. 相似文献
108.
Kitamura Y Kawata K Tanaka K Furuyashiki Y Mifune M Tsukamoto I Saito M Haginaka J Saito Y 《Talanta》2006,69(5):1260-1264
The effect of bromination of Cu-porphyrin-derivative-immobilized silica gels (Cu-TCPPD) was examined by comparing the retention behaviors of polyaromatic hydrocarbons (PAHs) on Cu-TCPPD and Cu-octabromotetrakis(4-carboxyphenyl)porphine-derivative-immobilized silica gels (Cu-OBTCPPD) columns. It was revealed that bromination affects strongly the π–π electron interactions caused from hydration energy in a polar eluent (80% methanol) possibly as a result of a destruction of planar structure of porphine-ring by bromination. It was also revealed that bromination enhances π–d interactions as well as the π–π electron interactions in a broad sense (e.g., dispersion forces) in a non-polar eluent (n-hexane). However, the bromination did not exert much influence on electrostatic interactions caused from polarization of mono-halogenated benzenes. 相似文献
109.
Let T be an integer with T?5 and let T2={2,3,…,T}. We consider the nonlinear discrete boundary value problem
110.
Y. Imai E. F. Johnson T. Katto M. Kurihara J. K. Stille 《Journal of polymer science. Part A, Polymer chemistry》1975,13(10):2233-2249
The condensation of bisketomethylene monomers with either 4,6-dibenzoyl-1,3-phenylenediamine or 2,5-dibenzoyl-1,4-phenylenediamine catalyzed by acid affords high molecular weight polymers containing the anthrazoline and isoanthrazoline units in the polymer main chain. Base is not an effective catalyst for the production of high molecular weight polymer. The phenyl substitution on the anthrazoline and isoanthrazoline units increases the solubility of these polymers over those in which phenyl substitution is absent. The rodlike character of these polymers, which can be altered by positional isomerism in the chain, has an effect on the solution properties. 相似文献