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排序方式: 共有1149条查询结果,搜索用时 62 毫秒
121.
Maxim V. Shugaev Nadezhda M. Bulgakova 《Applied Physics A: Materials Science & Processing》2010,98(1):103-109
On the basis of a two-temperature model taking into account the laser-generated stress waves, we have performed an analysis
of heating and melting dynamics in different metallic films (Au, Zn, Cr) irradiated by femtosecond laser pulses for the experimental
conditions on laser-induced forward transfer. The modeling results have allowed puzzling out why, even within the same family
of materials, substances can be transferred in the different phase states under rather similar laser-irradiation conditions. 相似文献
122.
Maxim O. Korpusov Dmitry V. Lukyanenko Alexander A. Panin 《Mathematical Methods in the Applied Sciences》2020,43(11):6771-6800
This work develops the theory of the blow-up phenomena for Joseph–Egri equation. The existence of the nonextendable solution of two initial-boundary value problems (on a segment and a half-line) is demonstrated. Sufficient conditions of the finite-time blow-up of these solutions, as well as the analytical estimates of the blow-up time, are obtained. A numerical method that allows to precise the blow-up moment for specified initial data is proposed. 相似文献
123.
Maxim Trokhimtchouk 《Calculus of Variations and Partial Differential Equations》2010,37(3-4):407-422
In this paper I discuss nonlinear parabolic systems that are generalizations of scalar diffusion equations. More precisely, I consider systems of the form $$\mathbf{u}_t -\Delta\left[ \mathbf{\nabla}\Phi(\mathbf{u})\right] = 0,$$ where ${\Phi(z)}$ is a strictly convex function. I show that when ${\Phi}$ is a function only of the norm of u, then bounded weak solutions of these parabolic systems are everywhere Hölder continuous and thus everywhere smooth. I also show that the method used to prove this result can be easily adopted to simplify the proof of the result due to Wiegner (Math Ann 292(4):711–727, 1992) on everywhere regularity of bounded weak solutions of strongly coupled parabolic systems. 相似文献
124.
Hunter M Backman V Popescu G Kalashnikov M Boone CW Wax A Gopal V Badizadegan K Stoner GD Feld MS 《Physical review letters》2006,97(13):138102
Light scattered from biological tissues can exhibit an inverse power law spectral component. We develop a model based on the Born approximation and von Karman (self-affine) spatial correlation of submicron tissue refractive index to account for this. The model is applied to light scattering spectra obtained from excised esophagi of normal and carcinogen-treated rats. Power law exponents used to fit dysplastic tissue site spectra are significantly smaller than those from normal sites, indicating that changes in tissue self-affinity can serve as a potential biomarker for precancer. 相似文献
125.
Standard assumptions in shock models are that failures of items are related either to the cumulative effect of shocks (cumulative models) or that they are caused by shocks that exceed a certain critical level (extreme shocks models). In this paper, we present useful generalizations of this setting to the case when an item is deteriorating itself, for example, when the boundary for the fatal shock magnitude is decreasing with time. Three stochastic failure models describing different impacts of shocks on items are considered. The cumulative effect of shocks is modeled in a way similar to the proportional hazards model. Explicit formulas for the corresponding survival functions are derived and several simple examples are considered. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
126.
Maxim Vybornov 《代数通讯》2013,41(12):3985-3992
In this paper we study finite dimensional algebras arising from categories of perverse sheaves on finite regular cell complexes (cellular perverse algebras). We prove that such algebras are quasi-hereditary and have finite global dimension. We discuss some restrictions, under which cellular perverse algebras are Koszul. We also study the relationship between Koszul duality functors in the derived categories of categories of graded and non-graded modules over an algebra and its quadratic dual. 相似文献
127.
Denis N. Tomilin Maxim D. Gotsko Lyubov N. Sobenina Igor A. Ushakov Boris A. Trofimov 《Tetrahedron letters》2019,60(28):1864-1867
The cycloadducts of menthofuran with acylbromoacetylenes, (3-bromo-1,6-dimethyl-5,6,7,8-tetrahydro-2H-2,4a-epoxynaphthalen-4-yl)(aryl)methanones, rearrange (CHCl3, reflux, 1 h) to 2-(2-acylethyl)benzofurans (along with the expected 2-bromo-3-hydroxy-4,7-dimethyl-5,6,7,8-tetrahydronaphthalene-1-yl)(aryl)methanones) via 2-acylethynylmenthofurans, thus indicating the exceptionally mild and rapid transfer of four hydrogens from a cyclohexane ring to a triple bond through the furan moiety in the key intermediate 2-acylethynylmenthofuran. 相似文献
128.
Artem L. Gushchin Bee‐Lean Ooi Pernille Harris Pavel A. Abramov Maxim N. Sokolov 《无机化学与普通化学杂志》2019,645(4):398-401
The aqueous solution chemistry of niobium is underexplored, and well characterized aqua complexes are scarce. In this contribution, a new niobium aqua complex was obtained by treatment of Zn‐reduced ethanolic solution of NbCl5 with HCl in the presence of a selenide source (ZnSe). This is the first example of selenium containing aqua complex of niobium. The yellow‐green aqua complex was isolated by cation‐exchange chromatography and transformed into corresponding isothiocyanate complex by ligand exchange, which was crystallized as (PyH)4.5[H1.5Nb4SeO5(NCS)10] · 0.5H2O. X‐ray structural analysis revealed a metal‐metal bonded tetranuclear {Nb4(μ4‐Se)(μ2‐O)5}4+ core with a capping μ4‐Se ligand. 相似文献
129.
Snke Oswald Nathan A. Seifert Fabian Bohle Maxim Gawrilow Stefan Grimme Wolfgang Jger Yunjie Xu Martin A. Suhm 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(15):5134-5138
1,1,1,3,3,3‐hexafluoro‐propan‐2‐ol aggregates preferentially into an achiral dimer of achiral monomers, but the trimer is found to prefer three metastable chiral monomer units arranged into a strained OH???O hydrogen‐bonded ring, which is reinforced by secondary CH???FC interactions. This is shown by a combination of infrared, microwave, and Raman spectroscopy in supersonic jet expansions and supported by high‐level quantum chemical calculations. It involves an activation of the monomers by >15 kJ mol?1, clearly driven by the much stronger hydrogen‐bond interaction available to the gauche and even more to the cis monomer units. 相似文献
130.
Varun Natu James L. Hart Maxim Sokol Helen Chiang Mitra L. Taheri Michel W. Barsoum 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(36):12785-12790
MXenes have shown promise in myriad applications, such as energy storage, catalysis, EMI shielding, among many others. However, MXene oxidation in aqueous colloidal suspensions when stored in water at ambient conditions remains a challenge. It is now shown that by simply capping the edges of individual MXene flakes, Ti3C2Tz and V2CTz, by polyanions such as polyphosphates, polysilicates or polyborates, it is possible to quite significantly reduce their propensity for oxidation even when held in aerated water for weeks. This breakthrough resulted from the realization that the edges of MXene sheets are positively charged. It is thus an example of selectively functionalizing the edges differently from the MXene sheet surfaces. 相似文献