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101.
102.
Miguel A. Herrero Andrew A. Lacey Juan J. L. Velázquez 《Archive for Rational Mechanics and Analysis》1998,142(3):219-251
The pair of parabolic equations , , with a>0 and b>0 models the temperature and concentration for an exothermic chemical reaction for which just one species controls the reaction
rate f. Of particular interest is the case where , which appears in the Frank‐Kamenetskii approximation to Arrhenius‐type reactions. We show here that for a large choice of
the nonlinearity f(u,v) in (1), (2)(including the model case (3)), the corresponding initial‐value problem for (1), (2) in the whole space with
bounded initial data has a solution which exists for all times. Finite‐time blow‐up might occur, though, for other choices
of function f(u,v), and we discuss here a linear example which strongly hints at such behaviour.
(Accepted September 16, 1996) 相似文献
103.
104.
Capon RJ Ratnayake R Stewart M Lacey E Tennant S Gill JH 《Organic & biomolecular chemistry》2005,3(1):123-129
Biological and chemical profiling of an Australian strain of the fungus Aspergillus unilateralis(MST-F8675), isolated from a soil sample collected near Mount Isa, Queensland, revealed a complex array of metabolites displaying broad chemotherapeutic properties. Noteworthy among these metabolites were a unique series of highly modified dipeptides aspergillazines A-E, incorporating a selection of unprecedented and yet biosynthetically related heterocyclic systems. Co-occurring with the aspergillazines was the recently described marine-derived fungal metabolite trichodermamide A (cf. penicillazine), whereas re-fermentation of A. unilateralis in NaCl (1%) enriched media resulted in co-production of the only other known example of this structure class, the marine-derived fungal metabolite trichodermamide B. Further investigation of A. unilateralis returned the known terrestrial fungal metabolite viridicatumtoxin as the cytotoxic and antibacterial principle, together with E-2-decenedioic acid, ferulic acid, (7E,7'E)-5,5'-diferulic acid and (7E,7'E)-8,5'-diferulic acid. The aromatic diacids have previously been reported from the chemical and enzymatic (esterase) treatment of plant cell wall material, with their isolation from A. unilateralis being their first apparent reported occurrence as natural products. Structures for all metabolites were determined by detailed spectroscopic analysis and, where appropriate, comparison to literature data and/or authentic samples. 相似文献
105.
Analyses of masses and relative kinetic energies for metastable peaks may be achieved by the use in alternation of two types of linked scans of the electric sector voltage and magnetic field. The method is demonstrated by an appraisal of hydrogen exchange in molecular ions of 2-methyl-[2H3]-benzoic acid. 相似文献
106.
The preparation of several 4'-alkylphenylethyl- and trans-4'-alkylcyclohexyl-ethyl-4,4'-disubstituted biphenyls and their 2-fiuoro derivatives is described and their transition temperatures are reported. The effect on the transition temperatures caused by the replacement of a cyclohexane ring by a benzene ring and the effect of fluoro-substitution on nematic, smectic A and smectic B thermal stabilities is discussed. In these systems, and in others, when the lateral fluoro-substituent points towards the longer terminal aliphatic unit (alkyl or alkylcyclo-hexylethyl) it causes a greater depression of smectic properties. 相似文献
107.
Alkyl (2-dimethylamino)ethyl methyl phosphates are prepared and isomerize smoothly to the corresponding alkyl choline phosphates. 相似文献
108.
109.