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101.
A multiple generalization of elliptic hypergeometric series is studied through the Cauchy determinant for the Weierstrass sigma function. In particular, a duality transformation for multiple hypergeometric series is proposed. As an application, two types of Bailey transformations for very well-poised multiple elliptic hypergeometric series are derived. 相似文献
102.
Masatoshi Kozaki 《Tetrahedron letters》2008,49(18):2931-2934
A methodology for the stepwise construction of shape-persistent assemblies using snowflake-shaped dendrimers as the key modular building blocks was described. The Sonogashira coupling reaction of A3B-type Zn-porphyrin with A4-type free-base porphyrin afforded a cross-shaped covalent assembly. Intramolecular singlet energy transfer from peripheral Zn-porphyrin core to a free-base porphyrin core was observed. 相似文献
103.
An investigation by high-resolution transmission electron microscopy of the precipitation process during ageing a Cu–1.2?wt%Be–0.1?wt%Co alloy at 320°C has revealed that the transition phases follow a γ″→ γ″?+?γ′?→?γ sequence. The γ′ phase heterogeneously precipitates on the γ″ phase. The effects of an external stress on the nucleation and growth of disc-shaped γ″ and plate-shaped γ′ precipitates have been examined for the alloy aged at 320°C. A compressive stress applied in the [001] direction during ageing preferentially accelerates the nucleation and growth of the γ″ variant normal to the [001] axis among three crystallographically equivalent variants and the specific four γ′ variants formed on the γ″ variant normal to the [001] axis. A tensile stress does not significantly affect those of γ″ and γ′ precipitates. The critical diameter of the disc-shaped γ″ nucleus is estimated as about 1?nm from evaluation of the interaction energy between the applied stress and the misfit strains of γ″ precipitates. It is proposed that applied external stress does not affect the diffusion rate but the interphase boundary velocity. 相似文献
104.
Kato T Kawabata Y Fujii M Kato T Hato M Minamikawa H 《Journal of colloid and interface science》2007,312(1):122-129
Surfactant self-diffusion coefficients have been measured on a binary system of 1-O-beta-3,7-dimethyloctyl-D-maltopyranoside (beta-Mal(2)(Ger))/water and a mixed surfactant system of beta-Mal(2)(Ger)/1-O-beta-3,7-dimethyloctyl-D-glucopyranoside (beta-Glc(Ger))/water at 25 degrees C. For comparison, measurements have also been made on 1-O-beta-decyl-D-maltopyranoside (beta-Mal(2)C(10))/water and beta-Mal(2)C(10)/1-O-beta-decyl-D-glucopyranoside (beta-GlcC(10))/water. The hydrodynamic radius of beta-Mal(2)(Ger) micelles obtained from the micellar diffusion coefficient is around 3 nm and nearly equal to that of beta-GlcC(10) micelles within experimental error. In the mixed surfactant systems, the hydrodynamic radii for both systems increase with increasing X(G) (the mole fraction of beta-Glc(Ger) or beta-GlcC(10) in the total mixed solute) above X(G) congruent with 0.4 when the total surfactant concentration is kept constant at 2 wt%. The R(H) of beta-Glc(Ger)/Mal(2)(Ger) micelles increases more rapidly than beta-GlcC(10)/beta-Mal(2)C(10) micelles, and then phase separation occurs at X(G) congruent with 0.65. On the other hand, the R(H) of beta-GlcC(10)/beta-Mal(2)C(10) micelles continues to increase until the phase separation occurs at X(G) congruent with 0.92. Measurements have also been performed as a function of total surfactant concentration at constant X(G) (=0.6). The CMC of the beta-Glc(Ger)/Mal(2)(Ger) system is larger than that of the beta-GlcC(10)/beta-Mal(2)C(10) system as expected from the results of the pure surfactant systems published previously. The R(H) increases with increasing total surfactant concentration for both systems. At higher concentrations, the R(H) of beta-Glc(Ger)/Mal(2)(Ger) micelles increases more rapidly than beta-GlcC(10)/beta-Mal(2)C(10) micelles. These results can be explained by the fact that the geranyl and decyl chains have the same volume but different chain lengths. 相似文献
105.
The effect of oxygen isotope substitution on the transition temperature Tc of a superconducting (Nd1−xCex)2CuO4−δ system was studied, where the special synthetic method was taken to minimize ambiguous factors on the oxygen concentration and to guarantee the complete substitution of 16O by 18O. The isotope exponent in the relationship of Tc∝1/M was estimated to be less than 0.15 by magnetic susceptibility measurements. 相似文献
106.
Yoshida T Sakakibara K Asami M Chen KH Lii JH Allinger NL 《Journal of computational chemistry》2003,24(3):319-327
The MM3 force field has been extended to deal with the lithium amide molecules that are widely used as efficient catalysts for stereoselective asymmetric synthesis. The MM3 force field parameters have been determined on the basis of the ab initio MP2/6-31G* and/or DFT (B3LYP/6-31G*, B3-PW91/6-31G*) geometry optimization calculations. To evaluate the electronic interactions specific to the lithium amides derived from the diamine molecules properly, the Lewis bonding potential term for the interaction between the lithium atom and the nonbonded adjacent electronegative atom such as nitrogen was introduced into the MM3 force field. The bond dipoles were evaluated correctly from the electronic charges on the atoms calculated by fitting to the electrostatic potential at points selected. The MM3 results on the molecular structures, conformational energies, and vibrational spectra show good agreement with those from the quantum mechanical calculations. 相似文献
107.
Hideyuki Yoshida Junichiro Sonoda Junichi Ishida Masatoshi Yamaguchi 《Analytica chimica acta》2005,534(2):177-183
A simple screening method of organic aciduria by spectrofluorometric measurement of total dicarboxylic acids in human urine is described. This method is based on an intramolecular excimer-forming fluorescence derivatization with a pyrene reagent, 4-(1-pyrene)butanoic acid hydrazide (PBH). Dicarboxylic acids in urine were converted to the corresponding dipyrene-labeled derivatives by reaction with PBH in the presence of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and pyridine, and the derivatives afforded intramolecular excimer fluorescence (420-540 nm) which can clearly be discriminated from the normal fluorescence (360-420 nm) emitted from reagent blanks. The technique is so selective that it permits spectrofluorometric measurement of total amount of dicarboxylic acids by the direct derivatization of diluted urine samples. The same reaction mixture has also served as a liquid chromatographic (LC) sample for the separative determination of individual dicarboxylic acids. The spectrofluorometric data did not contradict with the LC data. These methods were usefully applied to preliminary screening test of glutaric aciduria. In conclusion, the present derivatization method allows rapid and direct determination of total amount of dicarboxylic acids in human urine samples. 相似文献
108.
A highly convergent total synthesis of gymnocin-A, a cyctotoxic polyether marine natural product, has been achieved. The synthesis features Suzuki-Miyaura coupling of the ABCD and FGHIJKLMN rings, stereoselective introduction of the C17 hydroxyl group, ring-closure of the F ring, and a late-stage incorporation of a 2-methyl-2-butenal side chain. 相似文献
109.
Kitagawa O Takahashi M Yoshikawa M Taguchi T 《Journal of the American Chemical Society》2005,127(11):3676-3677
In the presence of (R)-DTBM-SEGPHOS-Pd(OAc)2 catalyst, N-arylation of ortho-tert-butyl-NH-anilides with 4-nitroiodobenzene proceeds with high enantioselectivity (89-95% ee) to give optically active atropisomeric anilides possessing N-C chiral axis. Furthermore, the intramolecular version of the present catalytic asymmetric N-arylation gave atropisomeric lactams with high optical purity (94-96% ee). 相似文献
110.
Tetsuya Masuda Katsuhisa Mimachi Yoshiomi Nakagami Masatoshi Noumi Yutaka Saburi Kimio Ueno 《Letters in Mathematical Physics》1990,19(3):187-194
Real forms of the quantum universal enveloping algebraU
q
(sl(2)) and a topological quantum group associated with this algebra are discussed. 相似文献