广义严格对角占优矩阵新的判定准则

In this paper we provide the new criteria for a strictly generalized diagonally dominant matrix, and it proves by an example that the results of this paper extend the results in[6]. In addition, we obtain the criteria of the nonsingular M-matrix.     

全对称傅里叶透镜的设计

本文研究了傅里叶透镜的设计,并叙述了一种对称型傅里时变换透镜.在相对孔径1:10时,输入面和频谱面处的象质均较好.傅里叶交换透镜的特点是必须对两对物象共轭位置(即位于前焦面处的输入面和位于后焦面处的频谱面)控制除畸变以外的全部象差.1969年后开始出现的傅里叶变换透镜,多属6～8片的对称或近似对称的四组元双远距型,本文叙述了一种严格对称型四片傅里叶交换透镜.     

The global dynamics of a class of vector fields in ℝ<Superscript>3</Superscript>

In this paper, we find a bridge connecting a class of vector fields in ℝ³ with the planar vector fields and give a criterion of the existence of closed orbits, heteroclinic orbits and homoclinic orbits of a class of vector fields in ℝ³. All the possible nonwandering sets of this class of vector fields fall into three classes: (i) singularities; (ii) closed orbits; (iii) graphs of unions of singularities and the trajectories connecting them. The necessary and sufficient conditions for the boundedness of the vector fields are also obtained.     

The challenge in managing new financial risks: adopting an heuristic or theoretical approach

The financial crisis began with the collapse of Lehman Brothers and the subprime asset backed securities debacle. Credit risk was turned into liquidity risk, resulting in a lack of confidence among financial institutions. In this article, we will propose a way to model liquidity risk and the credit risk in best practices. We will show that liquidity risk is a new type of risk and the current way to deal with it is based solely on observed variables without any theoretical link. We propose an heuristic approach to combine the numerous liquidity risk indicators with a logistic regression for the first time. In regards to credit risk, several articles prove that the best practice is to use an option model to appreciate this risk. We will present our methodology using stochastic diffusion for the interest rate because currently the yield curves aren’t liquid. This approach is more relevant because the basis model in prior publications has a constant interest rate or a forward rate. Both models allow a better understanding of liquidity and credit risks and the further development of research deals with the link between these two financial risks.     

Effects and Corrections for Mobile NMR Measurement

Nuclear magnetic resonance (NMR) under motion has drawn significant attention in recent years. Motion of the NMR probe has serious effects on NMR measurement. For example, NMR logging normally runs at downhole condition with tool motion at a speed of 30 ft/min. We propose here methods for motion corrections of NMR data based on the quantitative analysis of motion effects on polarization and echo acquisition. We also produced a multi-functional NMR scanning system to verify the theoretical analysis. Presented experiments demonstrate that the theoretical and experimental results match very well.     

Rigid geometric structures,isometric actions,and algebraic quotients

By using a Borel density theorem for algebraic quotients, we prove a theorem concerning isometric actions of a Lie group G on a smooth or analytic manifold M with a rigid A-structure σ. It generalizes Gromov’s centralizer and representation theorems to the case where R(G) is split solvable and G/R(G) has no compact factors, strengthens a special case of Gromov’s open dense orbit theorem, and implies that for smooth M and simple G, if Gromov’s representation theorem does not hold, then the local Killing fields on [(M)\tilde]{\widetilde{M}} are highly non-extendable. As applications of the generalized centralizer and representation theorems, we prove (1) a structural property of Iso(M) for simply connected compact analytic M with unimodular σ, (2) three results illustrating the phenomenon that if G is split solvable and large then π ₁(M) is also large, and (3) two fixed point theorems for split solvable G and compact analytic M with non-unimodular σ.     

交换子群较小的一类有限p群

研究了阶为p(m(m+1)/2)且交换子群的最大阶为p(m)的有限群,得到了这类特殊的p群的几个性质,给出了满足极大类条件的这类p群的同构分类.     

带导数项的半正Right Focal边值问题单调正解的存在性

研究下列半正Right F0cal边值问题单调正解的存在性其中λ>0是一个参数,n≥3,1相似文献   

Bidirectional Controlled Teleportation via Six-Qubit Cluster State

We present a scheme for bidirectional controlled teleportation by using a six-qubit cluster state as quantum channel. Based on the C-not operation and single qubit measurements, Alice may transmit an arbitrary single qubit state of qubit A to Bob and Bob may transmit an arbitrary single qubit state of qubit B to Alice via the control of the supervisor Charlie.     

面向空耦电声换能器应用的高性能FEP/PTFE复合膜压电驻极体

压电驻极体(也称为铁电驻极体)是一类具有强压电效应的微孔结构驻极体材料,具有柔韧、低密度、低特性声阻抗等特征,是制备柔性空气耦合声电换能器的理想材料.针对器件对高灵敏度和高温工作环境的应用需求,本文报道高性能氟化乙丙烯/聚四氟乙烯(FEP/PTFE)复合膜压电驻极体的制备和性能表征.研究结果表明,FEP/PTFE膜的特...