Quasi-optical measurement of complex dielectric constant at 300 GHz

A two beam interferometer in the Martin-Puplett configuration is used to determine the complex dielectric constant at 300 GHz of teflon, TPX-plastics, SPECTRALON and paraffin waxes with melting temperatures of 48° C and 72° C, respectively. The design of the quasi-optical system leads to a constant beam diameter at the power detector independent of path delay and frequency. The power detector signal is recorded not only along one period but over about 50 periods. A spectrum estimation routine allows to determine more exactly amplitude and phase angle of the signal. A basic problem is noticed: imperfect detector and source match cause harmonic distortion of the power detector signal. The effects on processing the loss tangent and the invalidation are shown. Finally loss tangent and dielectric constant are determined indirectly by optimizing an equivalent microwave circuit using a commercial available microwave design system to take multiple reflections and losses in consideration.     

大鼠骨骼肌细胞介电谱的测量

在100Hz-100MHz频率范围内,应用Agilent4294A阻抗分析仪测量了骨骼肌纤维走行与电场呈垂直方向的大鼠离体骨骼肌细胞介电谱,利用Cole—Cole图、介电损耗因子频谱、介电损耗角正切频谱等分析,建立了大鼠骨骼肌细胞介电特性数据特征．     

The Closed Orbits of a Class of Cubic Vector Fields in R3

In this paper, we investigate the isolated closed orbits of two types of cubic vector fields in R₃ by using the idea of central projection transformation, which sets up a bridge connecting the vector field X(x) in R₃ with the planar vector fields. We have proved that the cubic vector field in R₃ can have two isolated closed orbits or one closed orbit on the invariant cone. As an application of this result, we have shown that a class of 3-dimensional cubic system has at least 10 isolated closed orbits located on 5 invariant cones, and another type of 3-dimensional cubic system has at least 26 isolated closed orbits located on 13 invariant cones or 26 invariant cones.     

Contingent cone to a set defined by equality and inequality constraints at a Fréchet differentiable point

In this paper, we prove equality expression for the contingent cone and the strict normal cone to a set determined by equality and/or inequality constraints at a Fréchet differentiable point. A similar result has appeared before in the literature under the assumption that all the constraint functions are of classC or under the assumption that the functions are strictly differentiable at the point in question. Our result has applications to the calculation of various kinds of tangent cones and normal cones.This research was supported, in part by the National Science and Engineering Research Council of Canada under Grant No. OGP-41983.The authors would like to thank D. E. Ward for his many helpful comments.     

Characterization of near-millimeter wave materials by means of non-dispersive fourier transform spectroscopy

We have used non-dispersive Fourier-transformspectroscopic techniques to measure the complex indices of refraction of materials between frequencies of 120 and 550 GHz. Results are presented for crystal quartz, crosslinked polystyrene (Rexolite 1422), glass-loaded polytetrafluoroethylene (Duroid 5880) and a nickel ferrite (Trans-Tech 2-111). These results are compared with other data on these materials in this frequency range. The accuracy of these measurements yields a considerable improvement in the near-millimeter-wave characterization of several of these materials. For materials other than crystal quartz, our results are the first measurements of their properties over the entire frequency range studied.     

Properties of Epoxy Systems with Clay Nanocomposites

Different types of montmorillonite clays are often used for the modification of thermoplastic polymers. In the case of epoxy systems, the presence of the clays can complicate the cure process. Therefore, the influence of montmorillonite concentration and the temperature regime on the cure rate and mechanical properties of the composite material obtained is investigated in this paper.     

Another application of Guignard's generalized Kuhn-Tucker conditions

Necessary conditions are given for a real-valued function to have a minimum, subject to a generalized inequality constraint. Under the appropriate hypotheses, the problem is demonstrated to be a special case of the type of problem to which Guignard's Kuhn-Tucker theorem can be applied.The author would like to thank the referee for his valuable suggestions.     

Euler Characteristic and Fixed-Point Theorems

We propose a geometric definition of the Euler characteristic (M) for the class of compact epi-Lipschitzian sets MRⁿ and we provide existence theorems of (generalized) equilibria for set-valued mappings F when the domain M of F is neither assumed to be convex, nor smooth but has a nonzero Euler characteristic.     

多目标规划有效解的Kuhn—Tucker必要条件

本文提出一个新的约束规格,导出可微多目标规划的有效解的Kuhn-Tucker必要条件,并证明在此条件下,有效解是Kuhn-Tucker真有效解。     

Newton—Riemann时空中的动力学（Ⅳ）

讨论了Newton-Riemann时空中的Lagrange力学及其与N－R时空中的Newton力学及Hamilton力学的关系。