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981.
D. Vencatachellum 《Journal of Optimization Theory and Applications》1998,96(1):175-189
This paper compares the outcomes of strategic and nonstrategic research and development (R&D). Firms undertake cost-reducing R&D in an environment where benefits accrue from their rivals' R&D via a common pool of knowledge. We demonstrate that multiple suboptimal equilibria exist; under these conditions, growth models which do not consider strategic interactions will overestimate or underestimate the growth rate. 相似文献
982.
本文在文[1]的基础上进一步拓广了随机Solow经济增长模型.利用白噪声分析理论建立的广义随机Solow经济增长模型,将随机Solow模型推广到包含广义白噪声泛函及具有非可料扩散系数的情形,并且借助U—泛函方法表明了Picard迭代法在此仍十分有效. 相似文献
983.
研究了非共轭聚喹啉铝(Palq)在氯仿和乙醇不同极性的溶剂下所获得的薄膜的吸收和发光光谱。由于溶剂性的不同,聚喹啉铝链在氯仿和乙醇溶液中表现出不同的聚集状态。当各种溶液分别旋涂成膜时,溶液中的聚喹啉铝的聚集态仍部分地保存下来,导致不同聚喹啉铝薄膜的电子结构状态的差别。结果,聚喹啉铝的薄膜表现出不同的发光特性。实验表明,在制作聚合物器件中,溶剂的选择对共轭聚合物的发光特性有着重要的影响。 相似文献
984.
Th. Hahn H. Metzner J. Eberhardt J. Kräußlich S. Siebentritt 《Journal of Physics and Chemistry of Solids》2005,66(11):1899-1902
Epitaxial layers of the quaternary compound Cu(In,Ga)S2 and the ternary compound CuInS2 were grown on Si(111) substrates via Molecular Beam Epitaxy. The layers were investigated for their morphological and structural properties using Rutherford backscattering spectroscopy, atomic force microscopy, reflection high-energy electron diffraction and X-Ray diffraction. Furthermore, complete solar cell devices were processed from these layers and their photovoltaic properties were investigated by means of I(U)-curves under illumination. Thus, efficiencies up to η=3.2% were achieved. The comparatively low performance of the solar cell devices is attributed to certain heterogeneities of the samples as a result of the growth process. 相似文献
985.
Global Existence for a Parabolic-hyperbolic Free Boundary Problem Modelling Tumor Growth 总被引:1,自引:0,他引:1
Shang-bin Cui Xue-mei Wei 《应用数学学报(英文版)》2005,21(4):597-614
In this paper we study a free boundary problem modelling tumor growth, proposed by A. Friedman in 2004. This free boundary problem involves a nonlinear second-order parabolic equation describing the diffusion of nutrient in the tumor, and three nonlinear first-order hyperbolic equations describing the evolution of proliferative cells, quiescent cells and dead cells, respectively. By applying Lp theory of parabolic equations, the characteristic theory of hyperbolic equations, and the Banach fixed point theorem, we prove that this problem has a unique global classical solution. 相似文献
986.
Yusuke Higuchi 《Annals of Global Analysis and Geometry》2003,24(3):201-230
We introduce the boundary area growth as a new quantity for an infinite graph. Using this, we give some upper bounds for the bottom of the spectrum of the discrete Laplacian which relates closely to the transition operator. We also give some applications and examples. 相似文献
987.
We obtain sufficient conditions for the set of roots of an entire function of order zero of strongly regular growth to possess an angular density. 相似文献
988.
Belinda B. King Oliver Stein Michael Winkler 《Journal of Mathematical Analysis and Applications》2003,286(2):459-490
We study the continuum model for epitaxial thin film growth from Phys. D 132 (1999) 520-542, which is known to simulate experimentally observed dynamics very well. We show existence, uniqueness and regularity of solutions in an appropriate function space, and we characterize the existence of nontrivial equilibria in terms of the size of the underlying domain. In an investigation of asymptotical behavior, we give a weak assumption under which the ω-limit set of the dynamical system consists only of steady states. In the one-dimensional setting we can characterize the set of steady states and determine its unique asymptotically stable element. The article closes with some illustrative numerical examples. 相似文献
989.
P. Evans C. Scheck R. Schad G. Zangari 《Journal of magnetism and magnetic materials》2003,260(3):467-472
The structural and magnetic properties of Ni films grown by electrodeposition from simple sulfate solutions directly onto the (0 0 1) and (0 1 1) surfaces of n-GaAs have been studied. In-plane X-ray diffraction has been used to show that Ni grows on (0 0 1) GaAs with two different preferred epitaxial relationships: (1) perpendicular to plane (0 0 1)Ni(0 0 1)GaAs and preferred orientation in-plane [1 0 0]Ni[1 1 0]GaAs and (2) perpendicular to plane (0 1 1)Ni(0 0 1)GaAs and preferred orientation in-plane [1 1 1]Ni[1 1 0]GaAs. Nickel films grown on (0 1 1) n-GaAs show only a single preferred growth relationship: perpendicular to plane (1 1 1)Ni(0 1 1)GaAs and in-plane [1 1 0]Ni[1 1 0]GaAs. The magnetic properties were strongly dependent on the substrate orientation. The films grown on GaAs (0 0 1) showed a small but definite four-fold magnetic anisotropy in plane with the highest remanence being found along the GaAs [1 0 0] direction. In contrast, the Ni films grown on the (0 1 1) GaAs showed a pronounced uniaxial anisotropy with an anisotropy field of approximately 500 Oe. 相似文献
990.
KUNIMATSU NOBORU; SANO HIDEKI 《IMA Journal of Mathematical Control and Information》1998,15(4):317-330
This paper investigates the exponential stabilily of a modelof a heat exchanger of counterflow type, whose boundary conditionsare governed by boundary feedbacks. A theorem by F.L. Huangis applied to prove that the system satisfies the spectrum-determinedgrowth assumption. 相似文献