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1.
Global bifurcation of positive solutions for some degenerate quasilinear elliptic problems is considered. The uniform estimate
of the gradient of weak solutions is given. This estimate is crucial in our arguments.
Received: 10 August 2001
Supported in part by Grant-in-Aid for Scientific Research (No. 11640207), Ministry of Education, Science, Sports and Culture,
Japan.
Mathematics Subject Classification (2000): 35B32, 35J25, 35J70 相似文献
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Abou El-Nasr EA Fujii A Yahagi T Ebata T Mikami N 《The journal of physical chemistry. A》2005,109(11):2498-2504
Geometric structures and excited-state proton dislocation of size-selected salicylic acid clusters (salicylic acid and 5-methoxysalicylic acid) with water were studied by using laser spectroscopic techniques. Fluorescence excitation, dispersed fluorescence, and infrared (IR) spectra of those clusters in supersonic jets were examined for both the electronic ground (S0) and first excited (S1) states. The geometric structures of the clusters were determined on the basis of the IR spectra of the OH stretch region with the help of quantum chemical calculations. The hydroxyl group of the water moiety in the clusters forms a ring involving the carboxylic group of the salicylic acid moiety. The IR spectra in S0 show that the intramolecular hydrogen bond in the salicylic acid moiety is still held upon cluster formation, but the phenolic OH stretch band intensity is remarkably weaken in the clusters. The IR spectra in the S1 state and dispersed fluorescence spectra indicated that the intramolecular excited state proton dislocation is hardly affected by the microsolvation with water, in contrast with the strong suppression of the dislocation in the self-solvation. 相似文献
5.
The effects of self cooling on the apparent kinetics of the nonisothermal dehydration of crushed crystals of lithium sulfate monohydrate were investigated using TG accompanied by DTA and power-compensation type DSC. Linearity of the sample heating rate on the TG-DSC system is much better than that on the TG-DTA. Kinetic obedience and Arrhenius parameters obtained from the TG-DTA deviate considerably from those obtained from the TG-DSC; the latter are the more accurate due to the better linearity of the sample heating rate.
We thank Dr. A. K. Galwey for reading the text and for valuable comments. 相似文献
Zusammenfassung Mittels TG, ergänzt durch DTA und DSC mit Leistungskompensation wurde der Einfluß des Self-cooling-Effektes auf die scheinbare Kinetik der nichtisothermen Dehydratation von zerkleinerten Kristallen aus Lithiumsulfat-Monohydrat geschätzt. Die mittels TG-DTA erhaltene Kinetik und die Arrheniusschen Parameter weichen erheblich von denen ab, die mittels TG-DSC ermittelt wurden. DSC mit Leistungskompensation und TG-DSC haben gegenüber TG oder TG-DTA den großen Vorteil, das nichtisotherme kinetische Verhalten von Feststoffzersetzungen zu charakterisieren. Mittels Thermoanalyse nichtisotherm ermittelte kinetische Parameter sind ohne Anwendung von DSC eher unreell, besonders wenn sie bei größeren Aufheizgeschwindigkeiten und Probengrößen bestimmt wurden.
We thank Dr. A. K. Galwey for reading the text and for valuable comments. 相似文献
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Stereoselective polymerization of racemic lactide (rac-LA) was examined using Al-achiral ligand complexes. By introduction of substituents in aromatic rings of Schiff base ligands, a higher selectivity was obtained without any chiral auxiliaries in the catalyst via a chain-end control mechanism. The T(m) values (T(m) 170-192 degrees C) were comparable to or higher than that of homochiral polymer, poly(L-LA) (T(m) 162 degrees C), and a thermally more stable polylactide than poly(L-LA) was prepared from rac-LA. 相似文献
8.
We have measured the two-color double resonance enhanced four-photon ionization and the fluorescence de-enhanced spectra of nitric oxide by using two tunable pulsed dye lasers. The spectra show clear structure in the third-photon (8.2 eV) region. Also discussed is the multiphoton ionization mechanism in the resonance state. 相似文献
9.
Tan L Yasuda N Yoshikawa N Hartner FW Eng KK Leonard WR Tsay FR Volante RP Tillyer RD 《The Journal of organic chemistry》2005,70(20):8027-8034
[Chemical reaction: See text] A Et3Al mediated intramolecular epoxide opening, cyclopropanation reaction is described. The transformation provided highly functionalized bicyclo[3.1.0]hexane systems in high efficiency and with perfect H or F endo selectivity. Application of this reaction to the synthesis of mGluR2/3 agonist 1 (43% overall yield) and a few intermediates suitable for the synthesis of other bicyclo[3.1.0]hexane mGluR2/3 agonists is discussed. 相似文献
10.
Both the enantiomers of 2,3-dihydro-2-isopropyl-2,5-dimethylfuran were synthesized employing the Sharpless asymmetric epoxidation reaction. The (R)-(—)-enantiomer of this cyclic enol ether was also synthesized starting from (R)-(—)-linalool. 相似文献