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81.
Tadeusz Antczak 《Journal of Mathematical Analysis and Applications》2003,286(1):187-206
Invexity of a function is generalized. The new class of nonconvex functions, called B-(p,r)-invex functions with respect to η and b, being introduced, includes many well-known classes of generalized invex functions as its subclasses. Some properties of the introduced class of B-(p,r)-invex functions with respect to η and b are studied. Further, mathematical programming problems involving B-(p,r)-invex functions with respect to η and b are considered. The equivalence between saddle points and optima, and different type duality theorems are established for this type of optimization problems. 相似文献
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84.
Jianjun Liu Chun-gang DuanM.M Ossowski W.N MeiR.W Smith J.R Hardy 《Journal of Physics and Chemistry of Solids》2002,63(3):409-414
Structural phase transition in AgNO3 at high temperature is simulated by molecular dynamics. The simulations are based on the potentials calculated from the Gordon-Kim modified electron-gas formalism extended to molecular ionic crystals. AgNO3 transforms into rhombohedral structure at high temperature and the phase transition is associated with the rotations of the NO3 ions and displacements of the NO3 and Ag ions. 相似文献
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86.
Tadeusz Malarski 《Colloid and polymer science》1918,23(4):113-122
Ohne ZusammenfassungVorgelegt der Akad. d. Wiss. in Krakau in der Sitzung vom 6. Mai 1918.Am Schlusse erachte ich es als meine Pflicht, Herrn Prof. Godlewski sowohl für die Anregung zur vorliegenden Arbeit als auch für wohlwollende Weisungen und Ratschläge im Laufe der Untersuchungen meinen aufrichtigen Dank auszusprechen. 相似文献
87.
We study the semigroup of the symmetric α-stable process in bounded domains in R 2. We obtain a variational formula for the spectral gap, i.e. the difference between two first eigenvalues of the generator of this semigroup. This variational formula allows us to obtain lower bound estimates of the spectral gap for convex planar domains which are symmetric with respect to both coordinate axes. For rectangles, using “midconcavity” of the first eigenfunction (Bañuelos et al., Potential Anal. 24(3): 205–221, 2006), we obtain sharp upper and lower bound estimates of the spectral gap. 相似文献
88.
Traditional mathematical models of multiphase flow in porous media use a straightforward extension of Darcys equation. The key element of these models is the appropriate formulation of the relative permeability functions. It is well known that for one-dimensional flow of three immiscible incompressible fluids, when capillarity is neglected, most relative permeability models used today give rise to regions in the saturation space with elliptic behavior (the so-called elliptic regions). We believe that this behavior is not physical, but rather the result of an incomplete mathematical model. In this paper we identify necessary conditions that must be satisfied by the relative permeability functions, so that the system of equations describing three-phase flow is strictly hyperbolic everywhere in the saturation triangle. These conditions seem to be in good agreement with pore-scale physics and experimental data. 相似文献
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90.
Tomasz Rojek Tadeusz Lis Ewa Matczak‐Jon 《Acta Crystallographica. Section C, Structural Chemistry》2015,71(7):593-597
The asymmetric unit of the title salt, C12H24N+·C2H2BrO2−, contains a dicyclohexylammonium cation connected to a bromoacetate anion by means of an N—H...O hydrogen bond. In the crystal, the ion pairs assemble via N—H...O interactions, forming zigzag infinite chains parallel to the c axis with the (...H—N—H...O—C—O...)n motif that is considered to be a prerequisite for ensuring gelation properties of secondary ammonium monocarboxylate salts. The title salt was characterized by FT–IR, X‐ray powder diffraction (XRPD), TG–DTA and 1H NMR spectroscopy in solution. Gelation experiments revealed that dicyclohexylammonium bromoacetate forms molecular gels with dimethylformamide and dimethyl sulfoxide. Scanning electron microscopy (SEM) was used to reveal morphological features of dried gels. 相似文献