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51.
Global Existence of Solutions and Lower Bound Estimate of Blow-Up Time for the Keller-Segel Chemotaxis Model北大核心CSCD
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A macroscopic nonlinear Keller-Segel model for chemotactic cell migration was considered, where the existence region of the model is a bounded convex one on Ω ⊂ RN(N≥2). The global existence of the solution on Ω ⊂ R3 was obtained by means of the energy estimate method. The lower bound of the blow-up time was proved for N = 3 and N = 2. © 2022 Editorial Office of Applied Mathematics and Mechanics. All rights reserved. 相似文献
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In this paper we investigate two-point algebraic-geometry codes (AG codes) coming from the Beelen-Montanucci (BM) maximal curve. We study properties of certain two-point Weierstrass semigroups of the curve and use them for determining a lower bound on the minimum distance of such codes. AG codes with better parameters with respect to comparable two-point codes from the Garcia-Güneri-Stichtenoth (GGS) curve are discovered. 相似文献
56.
The root count developed by Bernshtein, Kushnirenko and Khovanskii only counts the number of isolated zeros of a polynomial system in the algebraic torus . In this paper, we modify this bound slightly so that it counts the number of isolated zeros in . Our bound is, apparently, significantly sharper than the recent root counts found by Rojas and in many cases easier to compute. As a consequence of our result, the Huber-Sturmfels homotopy for finding all the isolated zeros of a polynomial system in can be slightly modified to obtain all the isolated zeros in .
57.
Jim Coykendall 《Proceedings of the American Mathematical Society》1996,124(6):1727-1732
The image of the norm map from to (two rings of algebraic integers) is a multiplicative monoid . We present conditions under which is a UFD if and only if has unique factorization into irreducible elements. From this we derive a bound for checking if is a UFD.
58.
Krystyna Cieśla H. Rahier Grażyna Zakrzewska-Trznadel 《Journal of Thermal Analysis and Calorimetry》2004,77(1):279-293
One to three endothermal peaks atributted to melting of bulk and interfacial water were observed by DSC in the regenerated
cellulose — water system. The profiles of thermal effects depend on water content, time of conditioning, film pretreatment
and the conditions applied during the preceding freezing-thawing cycles. The occurrence might be deduced of melting-crystallisation
processes. A large amount of non-freezable strongly bounded water was also detected.
Although cellulose absorbs water quickly after immersion, the structural changes consisting on ordering of polymer fraction
occur during further conditioning due to increase in strength of water binding. Using the membranes in the separation module
at 90°C causes weakening of these bonds. Differences between interaction of particular cellulose films with water can be detected
during the first, the second and the third heating.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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Squalamine (1) was synthesized stereoselectively in 14 steps and 19% overall yield from 3-keto-5-chenodeoxycholanate (2) by using a modified Sharpless asymmetric dihydroxylation as the key step. 相似文献
60.
HuilingFan ChunhuLi HanxianGuo KechangXie 《天然气化学杂志》2003,12(1):43-48
The microkinetics os H2S removeal by ZnO desulfurization in H2O-CO2-N2,H2O-CO-N2 and H2O-O2-N2 gas mixtures was studied by thermogravimetric andlysis.Experiments were carried out with 100-120 mesh ZnO powder at temperatures from 473K to 563K.The results show that the kinetic behaviors of desulfurization could all be described by an improved shrinking-core model.The activation energies of the reaction and the diffusion in different gas atmospheres were estimated. 相似文献