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981.
Fangyan Lu 《Journal of Mathematical Analysis and Applications》2003,284(1):127-143
Let X be a real or complex Banach space. Let and be two nest algebras on X. Suppose that φ is an additive bijective mapping from onto such that φ(A2)=φ(A)2 for every . Then φ is either a ring isomorphism or a ring anti-isomorphism. Moreover, if X is a real space or an infinite dimensional complex space, then there exists a continuous (conjugate) linear bijective mapping T such that either φ(A)=TAT−1 for every or φ(A)=TA∗T−1 for every . 相似文献
982.
Fuzzy logic control has been used frequently in tuning network control system (NCS) due to its on-line dynamic static non-linear match and several remarkable fractional-order controllers have achieved satisfactory control performance when applied to NCS in present years, therefore, in this paper, a novel fractional fuzzy logic controller which combined the fractional algorithm and fuzzy logic control together has been proposed to deal with fixed and random network induced delays in closed-loop feedback systems. The comparisons of set-point tracking performances of fractional fuzzy logic PID controller (FFuzzyPID), conventional fuzzy logic PID controller(FuzzyPID), fractional optimal PID controller (FOPID), and optimal PID controller(OPID) on a representative plant with fixed and random network delays have been shown with simulations. The simulation results indicate that fractional fuzzy logic controller has higher capability to handle network delays compared with other controllers in most cases. 相似文献
983.
Effect of lattice strain on the oxygen vacancy formation and hydrogen adsorption at CeO2(111) surface 总被引:1,自引:0,他引:1
Using first-principles calculation, the effect of lattice strain on the oxygen vacancy formation at CeO2(111) surface has been investigated. The tensile strain facilitates the oxygen vacancy formation at the surface and the compressive strain hinders the process. This is in part due to the strengthening or weakening of the surface Ce–O bond under the lattice strain. On the other hand, a more open surface with a larger lattice constant can better accommodate the larger Ce3+ and thus facilitate the structural relaxation of the reduced surface. The studies on the strain effect on the atomic hydrogen adsorption at the defect-free CeO2(111) surface show that the adsorption strength monotonously increases with the increase of the lattice strain, further confirming the tunable surface chemical activity by lattice strain. 相似文献
984.
985.
采用带有开路磁芯的Tesla变压器与单筒脉冲形成线一体化结构,研制了一台基于Tesla变压器的紧凑GW级纳秒脉冲源,该源包括一个40 脉冲形成线、内置Tesla变压器、初级电路及高压吹气主开关等,具有变比高、结构紧凑、能量传输效率高、便于重复频率运行等特点。给出了脉冲形成线、Tesla变压器和主开关等的工作原理、设计方法和模拟计算。实验结果表明,该脉冲源输出电压大于200 kV,脉冲宽度约8 ns,可以在重复频率100 Hz、平均输出功率1 GW情况下稳定运行,实验结果与理论设计相符。 相似文献
986.
Let k be a subring of the field of rational functions in α, s which contains α
±1
,s
±1
. Let M be a compact oriented 3-manifold, and let K(M) denote the Kauffman skein module of M over k. Then K(M) is the k-module freely generated by isotopy classes of framed links in M modulo the Kauffman skein relations. In the case of , the field of rational functions in α, s, we give a basis for the Kauffman skein module of the solid torus and a basis for the relative Kauffman skein module of the
solid torus with two points on the boundary. We then show that K(S
1
× S
2
is freely generated by the empty link, i.e., .
Received: 20 October 2001 / Revised version: 20 March 2002 相似文献
987.
988.
989.
卢广存 《数学物理学报(B辑英文版)》2002,22(4)
In this note a symplectic capacity of Hofer-Zehnder type that is only invariant under C1-symplectomorphisms is defined and all computation formulae for Hofer-Zehnder symplectic capacity obtained at present are proved still holding for it. As a consequence some results on Weinstein conjecture are generalized to C1-smooth hypersurface of contact type. 相似文献
990.
Spatial Nonparametric Regression Estimation: Non-isotropic Case 总被引:3,自引:0,他引:3
Zu-di Lu Xing ChenInstitute of Systems Science Academy of Mathematics Systems Sciences Chinese Academy of Sciences. Beijing ChinaDepartment of Statistics Yunnan University Kunming China 《应用数学学报(英文版)》2002,18(4):641-656
Data collected on the surface of the earth often has spatial interaction. In this paper, a non-isotropic mixing spatial data process is introduced, and under such a spatial structure a nonparametric kernel method is suggested to estimate a spatial conditional regression. Under mild regularities, sufficient conditions are derived to ensure the weak consistency as well as the convergence rates for the kernel estimator. Of interest are the following: (1) All the conditions imposed on the mixing coefficient and the bandwidth are simple; (2) Differently from the time series setting, the bandwidth is found to be dependent on the dimension of the site in space as well; (3) For weak consistency, the mixing coefficient is allowed to be unsummable and the tendency of sample size to infinity may be in different manners along different direction in space; (4) However, to have an optimal convergence rate, faster decreasing rates of mixing coefficient and the tendency of sample size to infinity along each direction a 相似文献