Orthogonality Preserving Transformations on Indefinite Inner Product Spaces: Generalization of Uhlhorn's Version of Wigner's Theorem

We present an analogue of Uhlhorn's version of Wigner's theorem on symmetry transformations for the case of indefinite inner product spaces. This significantly generalizes a result of Van den Broek. The proof is based on our main theorem, which describes the form of all bijective transformations on the set of all rank-one idempotents of a Banach space which preserve zero products in both directions.     

对称正定问题多搜索方向共轭梯度法的收敛性理论

In this paper, we give the convergence and consistence theory of multiple search direction conjugate gradient method (see [10]) and give some upper bound estimations of iterative value and error of our method.     

关于素环的导子

设Ｒ是一个中心为Ｃ的素环，Ｎ是Ｒ的一个非零理想。本文我们将证明下列结果：假设ｄ是Ｒ的一个非零导子使得ｄ＾２（ａ＾２）∈Ｃ对一切ａ∈Ｎ或者〔ｄ（ａ），ａ＾２〕∈Ｃ对一切ａ∈Ｎ，那么当Ｒ的特征不等于２时，Ｒ是一个交换环。我们的结果推广了文献〔２，〔４〕，〔８〕中有关素环导子的某些已知结果。     

利用数字压缩技术频域内积和方差的分形编码算法

文中定义了图像块的数字压缩技术(DCT)频域内积,并证明了该内积等于时域内积, 从而可根据频域内积大小来作为分形编码中最佳匹配块的判断,并推导出DCT域上恒等变换与其余7种对称变换的关系。本文将值域块分为平稳、中间和活跃三类,研究对于不同类型的值域块,求频域内积时,保留低频系数个数和解码图像质量之间的关系,并提出了基于DCT域内积和方差的分形图像编码算法。在实验中,将本文算法分别同文献[ 2 ]、[ 3 ]中方法进行了比较,结果表明,本文算法能在基本保证解码图像质量的同时,大大提高编码速度。     

A Buzano type inequality for two Hermitian forms and applications

A Buzano type inequality for two nonnegative Hermitian forms is obtained. Applications to inequalities for norm and numerical radius of bounded linear operators in complex Hilbert spaces are given.     

On the structure of the automorphism group of certain automorphic loop

Automorphic loops, or A-loops, are loops in which all inner mappings are automorphisms. We investigated A-loops arising from a Lie algebra and describe their automorphism group. Also, we identify and describe their inner mapping group.     

Synchronization of complex networks with time‐varying inner coupling and outer coupling matrices

Synchronization of complex networks with time‐varying coupling matrices is studied in this paper. Two kinds of time‐varying coupling are taken into account. One is the time‐varying inner coupling in the node state space and the other is the time‐varying outer coupling in the network topology space. By respectively setting linear controllers and adaptive controllers, time‐varying complex networks can be synchronized to a desired state. Meanwhile, different influences of the control parameters of linear controllers and adaptive controllers on the synchronization have also been investigated. Based on the Lyapunov function theory, we construct appropriate positive‐definite functions, and several sufficient synchronization criteria are obtained. Numerical simulations further illustrate the effectiveness of conclusions. Copyright © 2017 John Wiley & Sons, Ltd.     

自辐射场下UN2分子的光谱研究

对铀原子和氮原子分别使用相对论有效原子实势和6-311+G(d)基组, 采用优选的密度泛函B3P86方法, 研究了铀本身产生自辐射场(-0.005–0.005 a.u.)作用下UN₂基态分子的能隙E_g和谐振频率ν. 结果表明: UN₂分子在自辐射场中反对称伸缩振动频率ν₃(σ_g)和对称伸缩振动频率σ₁(σ_g)与实验值1051.1 cm^-1和1008.3 cm^-1 基本符合; E_g随自辐射场场强的增大而趋于减少, 占据轨道的电子容易被激发至空轨道而形成激发态; UN₂分子在自辐射场中趋于不稳定, N₂, O₂等更容易扩散到表面内层而腐蚀铀表面, 加剧了铀在自辐射场中的腐蚀.     

超小型片式多层陶瓷电容器内电极印刷工艺研究

该文介绍了在超小型片式电容器内电极印刷中影响质量的诸多因素,并分析其原因,具体探讨了丝网网框、网布、丝印制版工艺对印刷质量的影响.结果表明,通过选用合适的网框、网布,使用镜面处理感光胶的制版技术,可以达到理想的印刷效果及合适的镍电极层厚度.