Influence of grooves in the electromagnetic transmission of a periodic metallic grating filter

The light transmittance of metal film with periodic slits and grooves structure has been investigated. It was demonstrated that the grooves significantly affect the transmittance of the metal film. The structure excavating two grooves symmetric to the central slit in a cell of a period grating displays a dent in the transmission spectrum comparing with the structure with only one slit in the cell. Deepening the grooves moves the dents to the longer wavelengths in the transmission spectrum. An analytical equation is also provided to approximately locate the dents. The grooves in the grating filter supply the advantage of removing the needless transmission of certain frequency.     

A ratio‐dependent predator–prey model with stage structure and optimal harvesting policy

In this paper, a ratio‐dependent predator–prey model with stage structure and harvesting is investigated. Mathematical analyses of the model equations with regard to boundedness of solutions, nature of equilibria, permanence and stability are performed. By constructing appropriate Lyapunov functions, a set of easily verifiable sufficient conditions are obtained for the global asymptotic stability of nonnegative equilibria of the model. The existence possibilities of bioeconomic equilibria have been examined. An optimal harvesting policy is also given by using Pontryagin's maximal principle. Copyright © 2007 John Wiley & Sons, Ltd.     

Nodal Solutions of a p-Laplacian Equation

We prove that the p-Laplacian problem –_p u = f(x, u),with u on a bounded domain R^N, with p > 1 arbitrary, has a nodal solution providedthat f : x R R is subcritical, and f(x, t) / |t|^p –² is superlinear. Infinitely many nodal solutions are obtainedif, in addition, f(x, –t) = –f(x, t). 2000 MathematicsSubject Classification 35J20, 35J65, 58E05.     

Continuity in quantitative domains

Based on the notion of an $L$-fuzzy partially ordered set constructed in (An L-fuzzy approach to quantitative domain (I)—generalized ordered set valued in frame and adjunction theory, Fuzzy Systems and Mathematics 14 (2000) 6–7), and by introducing the concepts of an $L$-fuzzy directed set and the join of an $L$-fuzzy set w.r.t. the $L$-fuzzy partial order, $L$-fuzzy domains are defined and the generalized Scott topology on an $L$-fuzzy domain is built. This approach is similar to Flagg's logic approach to quantitative domain theory (A Logical Approach to Quantitative Domain Theory, Elsevier, Amsterdam, 1996, submitted for publication). In addition, the concepts of stratified approximation and a basis for an $L$-fuzzy domain are proposed, and a notion of a continuous $L$-fuzzy domain is developed. It is proved that if $L$ is a completely distributive lattice in which 1 is $\vee$-irreducible and the well below relation is multiplicative, then the stratified interpolation property holds in a continuous $L$-fuzzy domain $(X,e)$, and $\{{\Uparrow }_{a}x\mid 0\ne a⋘1,x\in X\}$ is a base for the generalized Scott topology on $(X,e)$.     

治肺癌复方中铬,镍的形态分析

本实验对含１３味中药的治肺癌复方原药，头煎及二煎残渣和浸汁，经０．４５μ膜分离的颗粒物，可溶态，以及可溶态分别通过阳离子交换树脂，用三氯甲烷萃取后所得各自柱截留物，穿过物，有机相，水相等共１５个样品中铬，镍，按照中药微量元素初级和次形态分析的要求，进行分析测定，以此计算出一套形态分析参数和相关数据，为探讨中草约中微量元素的化学形态提供了新的信息。     

质子探针在流体包裹体分析中的应用

本文着重阐述了质子探针无标样定量分析流体包裹体的方法原理、技术要点和分析时注意的问题。作者对我国斑岩铜矿石英中的流体包裹体进行了分析,还就国内外质子探针分析流体包裹体的现状进行了评述和展望。     

对巯基苯甲酸在电化学沉积金膜表面的SERS研究

SERS技术由于具有高灵敏度的表面效应,能够检测吸附在金属表面的单分子层或亚单分子层的分子,并能给出丰富的分子结构信息,因而己被广泛应用于界面科学以及定性和定量分析科学领域之中。本文在制备电化学沉积金纳米薄膜的基础上,利用扫描电镜观察金纳米薄膜的形貌,通过分析对巯基苯甲酸在电化学沉积金膜表面的SERS光谱,研究对巯基苯甲酸在金纳米薄膜表面的吸附方式。由SERS光谱分析,我们推断出对巯基苯甲酸可能通过羧基和S原子共同作用吸附在金纳米颗粒表面,且苯环平面可能与金薄膜表面成一定倾斜角。     

Kähler manifolds with numerically effective Ricci class and maximal first Betti number are tori

Let M be a n-dimensional Kähler manifold with numerically effective Ricci class $c_1(M)$. In this Note we prove that, if the first Betti number $b_1(M)$ is equal to 2n, then M is biholomorphic to a n-dimensional complex torus. To cite this article: F. Fang, C. R. Acad. Sci. Paris, Ser. I 342 (2006).     

IR-SERS study and theoretical analogue on the adsorption behavior of pyridine carboxylic acid on silver nanoparticles

High qualities Raman spectra of pyridine carboxylic acid in silver colloidal solution and on silver-coated ITO glass at near infrared laser excitation were obtained in this article. The calculations based on density functional theory (DFT) were used to analysis the absorption behavior of these molecules. By comparing the experimental frequencies with the calculated ones, it can be concluded that the carboxylate-to-metal interaction is the key factor during the adsorption process, and the nitrogen-to-metal coordination seemed to play a secondary role in the process.     

Terahertz spectroscopic investigations of caffeine and 3-acetylmorphine

Experimental and theoretical investigations of THz spectral features of caffeine and 3-acetylmorphine in the region of 0.2-2.6 THz have been presented. The refractive indices and absorption coefficients of the two drugs were obtained by a terahertz time-domain spectroscopy (THz-TDS) technique. The simulated absorption spectra using the density functional theory (DFT) and Hartree-Fork (HF) are in agreement with the experimental data. The observed spectral absorption features were assigned based on DFT and HF calculation.