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排序方式: 共有497条查询结果,搜索用时 15 毫秒
451.
Gianni Gilardi 《Journal of Differential Equations》2006,228(2):707-736
This note addresses the analysis of an abstract doubly nonlinear Volterra equation with a nonsmooth kernel and possibly unbounded and degenerate operators. By exploiting a suitable implicit time-discretization technique, we obtain the existence of a global strong solution. As a by-product, the discrete scheme is proved to be conditionally stable and convergent. 相似文献
452.
Bruno Casetta Ron Bonner Bori Shushan Gianni Fior 《Journal of mass spectrometry : JMS》1992,27(3):211-214
The specific bovine and buffalo caseins have been characterized with the aim of using atmospheric pressure ionization mass spectrometry as an alternative to electrophoretic and immunological methods in the detection of the fraudulent addition of bovine milk to buffalo milk used in the production of speciality cheeses. 相似文献
453.
454.
Cravotto G Balliano G Tagliapietra S Oliaro-Bosso S Nano GM 《Chemical & pharmaceutical bulletin》2004,52(10):1171-1174
Squalene-hopene cyclase (SHC) is a useful model enzyme for predicting molecular interactions with oxidosqualene cyclase (OSC). Structure--activity relationships were investigated for numerous coumarin-derived inhibitors of SHC, and structural simplifications are suggested. Both umbelliferone and 2,4-dihydroxyacetophenone provide convenient starting nuclei for the design of SHC inhibitors. Derivatives bearing an omega-epoxyfarnesyl moiety or just a plain alkyl chain showed an inhibitory effect on a recombinant SHC from Alicyclobacillus acidocaldarius expressed in Escherichia coli. 相似文献
455.
The asymmetry of the blood flow in the human left ventricle is commonly assumed to facilitate the following ejection of blood in the primary circulation. The intraventricular flow is here studied by the numerical solution of the governing equations written in a prolate spheroid geometry with moving walls. The physiological parameters are taken from pediatric clinical data; then, the entering jet is artificially displaced to modify the asymmetry of the flow. The analysis of flow patterns confirms that the physiological case looks to best comply with the transition from the filling to the ejection phase. The flow energy dissipation is found to be minimized about the physiological conditions. An unnatural asymmetry, as given by cardiac diseases or valvular replacement, could reduce the efficiency of the heart pump by over 10%, thus augmenting the work required by the cardiac muscle. 相似文献
456.
Sforza S Galaverna G Corradini R Dossena A Marchelli R 《Journal of the American Society for Mass Spectrometry》2003,14(2):124-135
The study of unsubstituted and disubstituted beta-cyclodextrins (beta-CDs) by ESI-mass spectrometry is reported, applying a cone-induced fragmentation in the presence of a twofold excess of sodium chloride, in order to gain information about the fragmentation of the different regioisomers. On the basis of the fragmentation pattern observed for the unsusbstituted beta-CD, a statistical model shows that the fragments generated by every regioisomer of a disubstituted CD (AB, AC, and AD) are expected to differ in their relative intensity and, therefore, they can be used for correctly identifying the three different regioisomers. The model was tested on the three regioisomeric (AB, AC, and AD) diamino-beta-CDs and ditosyl-beta-CD and on the AC and AD regioisomers of dimesitylenesulphonyl-beta-CD, allowing in every case through statistical analysis of the fragmentation pattern the correct assignment of every regioisomer on the basis of an ESI mass spectrum (single quadrupole analyzer, high cone voltage) of the pure compounds. The absolute intensities of the fragmentation peaks were voltage-dependent but their ratios was voltage-independent, indicating that no mass bias in peak ratios is introduced by the analyzer. Given the fast time of analysis and its general applicability, independently from the substituents, we propose our method as an easy way to identify the regioisomers of disubstituted beta-CDs. 相似文献
457.
Gianni Cassinelli 《International Journal of Theoretical Physics》1993,32(12):2323-2333
In this paper we review the basic mathematical properties that allow the embedding of quantum state spaces into spaces of classical probability measures. In particular, the precise topological structures used for these immersions are described. 相似文献
458.
N-Methyl and N,N-dimethylalkylamines are converted into N-methyldialkyl-amines in good yields when heated at 180°C in the presence of a catalytic amount of RuCl2(Ph3P)3-. 相似文献
459.
Gianni Sacchiero 《Annali dell'Universita di Ferrara》1980,26(1):33-40
Riassunto In questa nota si determina la struttura del fibrato normale di una generica curva razionale nello spazio proiettivo.
Summary In this note we determine the structure of the normal bundle of a generic rational curve in the projective space.相似文献
460.
M. Amar D. Andreucci P. Bisegna R. Gianni 《Mathematical Methods in the Applied Sciences》2006,29(7):767-787
In this paper we derive a hierarchy of models for electrical conduction in a biological tissue, which is represented by a periodic array of period ε of conducting phases surrounded by dielectric shells of thickness εη included in a conductive matrix. Such a hierarchy will be obtained from the Maxwell equations by means of a concentration process η → 0, followed by a homogenization limit with respect to ε. These models are then compared with regard to their physical meaning and mathematical issues. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献