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991.
Experimental study of the ultrahigh-frequency chaotic dynamics generated in an improved Colpitts oscillator is performed. Reliable and reproducible chaos can be generated at the fundamental frequency up to 1.5 GHz using the microwave BFG520 type transistors with the threshold frequency of 9 GHz. By the tuning of the supply voltages, we observe complex nonlinear dynamics like period-one oscillation, period-two oscillation, multiple-period oscillation, and chaotic oscillation. Typical time series, autocorrelation, and broadband continuous power spectrum are presented. Furthermore, compared with the corresponding classical Colpitts oscillator, the main advantage of the improved circuit is in the fact that by operating in a chaotic mode it exhibits higher fundamental frequencies and a lower peak side-lobe level. 相似文献
992.
Let M n be a complete oriented noncompact hypersurface in a complete Riemannian manifold N n+1 of nonnegative sectional curvature with ${2 \leq n \leq 5}$ . We prove that if M satisfies a stability condition, then there are no non-trivial L 2 harmonic one-forms on M. This result is a generalization of a well-known fact in the case when M is a stable minimally immersed hypersurface. As a consequence, we show that if the mean curvature of M is constant, then either M must have only one end or M splits into a product of ${\mathbb{R}}$ and a compact manifold with nonnegative sectional curvature. In case ${n \geq 5}$ , we also show that the same result holds if the absolute value of the mean curvature is less than or equal to the ratio of the norm of the second fundamental form to the dimension of a hypersurface. 相似文献
993.
主要讨论了Hardy-Littlewood极大函数,Sharp极大函数以及分数次极大函数与BMO(R~n)函数生成的交换子在广义Morrey空间上有界性的等价刻画. 相似文献
994.
995.
In this paper, we construct a new class of finite groups whose common divisor graphs are complete graphs, while there is no prime dividing all the nontrivial degrees. 相似文献
996.
Pricing policies for substitutable products in a supply chain with Internet and traditional channels
This study considers pricing policies in a supply chain with one manufacturer, who sells a product to an independent retailer and directly to consumers through an Internet channel. In addition to the manufacturer’s product, the retailer sells a substitute product produced by another manufacturer. Given the wholesale prices of the two substitute products, the manufacturer decides the retail price of the Internet channel, and the retailer decides the retail prices of the two substitute products. Both the manufacturer and the retailer choose their own decision variables to maximize their respective profits. This work formulates the price competition, using the settings of Nash and Stackelberg games, and derives the corresponding existence and uniqueness conditions for equilibrium solutions. A sensitivity analysis of an equilibrium solution is then conducted for the model parameters, and the profits are compared for two game settings. The findings show that improving brand loyalty is profitable for both of the manufacturer and retailer, and that an increased service value may alleviate the threat of the Internet channel for the retailer and increase the manufacturer’s profit. The study also derives some conditions under which the manufacturer and the retailer mutually prefer the Stackelberg game. Based on these results, this study proposes an appropriate cooperation strategy for the manufacturer and retailer. 相似文献
997.
We study the stability of a robot system composed of two Euler–Bernoulli beams with non-collocated controllers. By the detailed spectral analysis, we prove that the asymptotical spectra of the system are distributed in the complex left-half plane and there is a sequence of the generalized eigenfunctions that forms a Riesz basis in the energy space. Since there exist at most finitely many spectral points of the system in the right half-plane, to obtain the exponential stability, we show that one can choose suitable feedback gains such that all eigenvalues of the system are located in the left half-plane. Hence the Riesz basis property ensures that the system is exponentially stable. Finally we give some simulation for spectra of the system. 相似文献
998.
§1. Preliminary Lemma Using A to denote the cardinal number of a finite set A, we do not explain anymore what are similar to A in this paper. For a given tree T(V,E), if there is a labeling f of its vertices, which satisfiesf[V(T)]={f(u)u∈V(T)}={0,1,2,…,E(T)},lf[E(T)]={lf(uv)=f(u)-f(v), uv∈E(T)}={1,2,…,E(T)},then f is called a graceful labeling of T, and T is called a graceful tree. lf denotes the labeling of edges that is derived from f. In the 1960s, RingedKotzing and A. R… 相似文献
999.
§ 1.Introduction Chainablecontinuahavebeenextensivelystudiedformanyyearsandhavegeneratednewinterestintherecentyearsasthechainablecontinuumwhichistheinverselimitspaceofacontinuousmapfromaclosedintervalintoitselfcanberealizedasaglobalattractorofsomeplan… 相似文献
1000.
In this article, we define a new associative dialgebra over a polynomial algebra F[x, y] with two indeterminates x and y. Left derivations, right derivations, derivations, and automorphisms of F[x, y] as associative dialgebra are determined. Meanwhile, we also determine all homogeneous derivations of F[x, y] as ?-graded Leibniz algebra, and automorphisms of Leibniz algebra F[x, y] preserving the standard filtration. 相似文献