表面增强喇曼散射效应在表面吸附动力学中的应用

1 基本理论 1.1 吸附量与时间的依赖关系设s(t)为单位面积t时刻的分子数,s_o是单位面积固体表面有效吸附位的总浓度.有 v_1=k_1[s_o-s(t))c(t)(1) 其中k_1是吸附速率常数,c(t)是t时刻溶液浓度.随着表面吸附的发生,其逆过程一脱附随即开始.脱附率正比于覆盖的分子数.有v_2=k_2s(t).式中k_2是脱附率常数.表面吸附量的变化为 (ds     

中华大蟾蜍输卵管直段的形态学和酯酶反应

直段上皮是由纤毛细胞和分泌细胞组成。冬眠后排卵前和秋季输卵管直段的分泌细胞内有大量的分泌颗粒,此外还有高尔基复合体、核糖体、环形片层以及少量的线粒体和脂滴。分泌细胞表面有大量长的微绒毛,因而在相邻的分泌细胞之间形成一个相互交错的网状结构。在冬眠后排卵前和秋季对直段分泌细胞内酯酶的检测呈阳性反应,排卵后9—10天或秋季的雌体注入 LHRH 可起增强酯酶反应作用。     

柱萃取色谱法分离铽和镝的研究

本文应用CL—P507革淋树脂作为萃取色谱柱填充料,进行希土元素Tb和Dy分离的研究.研究了淋洗酸度、温度、流速、希土负载量等因素对Tb-Dy离的影响.     

加强农村建房的管理与指导

从目前农村住房现状入手,分析了其存在的问题,并提出相关对策和解决措施,以期我国农村住宅建设得以健康、持续、稳定地发展.     

Quantitative Estimates of Outcrossing Rates in a Natural Population of Caldesia grandis （Alismataceae）

Outcrossing rate in a natural population of Caldesia grandis was estimated by the dominant random amplified polymorphism DNA (RAPD) marker using 10 open-pollinated progeny arrays of 24 individuals. The multilocus outcrossing rate estimated based on all 25 RAPD loci was 0.872 ±0.033 and the single-locus outcrossing rate was 0.795 ±0.032. Multilocus estimates did not differ significantly from the single-locus estimates. The fixation index, F, in the progeny estimated from RAPD data was -0.142 ±0.000. The estimates of multilocus outcrossing rates (t_m) and single-locus outcrossing rates (t_s) obtained from MLDT clearly indicate that outcrossing is predominant in the open-pollinated C. grandis population. An empirical analysis suggests that 15 should be the minimum number of dominant marker loci necessary to achieve robust estimates of t_m.     

Two-Way Digital Video Transmission over Medium-Voltage Power-Lines Using Time-Domain Synchronous Orthogonal Frequency Division Multiplexing Technology

This paper describes field trials of two-way digital video transmissions over a 700-m long medium-voltage power cable using a frequency division duplex scheme. The purpose is to check the feasibility of using time-domain synchronous orthogonal frequency division multiplexing (TDS-OFDM) technology in powerline communication (PLC). TDS-OFDM is the core technology in digital multimedia broadcasting-terrestrial (DMB-T), developed by Tsinghua University for digital television terrestrial multimedia broadcast applications and successfully adopted in the Chinese Digital Terrestrial Television Broadcasting Standard. PLC systems are widely believed to be bandwidth or data throughput limited. However, the use of known pseudo random sequences as guard intervals for synchronization and channel estimation in TDS-OFDM greatly reduces the system overhead and increases the spectrum efficiency. These experiments show that TDS-OFDM is appropriate not only for broadcasting but also for PLC applications with appropriate modifications.     

任务型泛读教学初探

文章首先探讨了任务型教学在国内外的研究动态,然后探讨了任务型教学中任务的定义、任务型教学的主要特点及设计原则.随后分析了任务型教学模式,即威利斯的前任务、任务环和后任务教学(即语言聚焦)模式.最后阐述了在大专英语泛读课教学中如何运用该教学模式及其应用后产生的效果,并且提出了实施过程中遇到的种种困难.     

A FRAMEWORK FOR REAL-VALUED CIPHER SYSTEMS

Most cipher systems designed thus far are binary-valued or integer-valued cipher systems. Their security relies on the assumption that one-way functions exist. Though the existence of one-way functions has not been proved yet, most cryptographic researchers believe that one-way functions exist. In addition, many candidates for one-way functions have been proposed. Therefore, the key step for developing real-valued cipher systems is to define real one-way functions and to propose candidates for them. In this paper, based on computational complexity theory over the real field, we give two definitions of real one-way functions; one is for digital one-way functions and the other is for general one-way functions. Candidates for these two classes of one-way functions are also proposed. Moreover, we present two examples to demonstrate that the candidates for both digital one-way functions and general one-way functions can be applied to construct secure real-valued cipher systems.     

D算子中立型随机泛函微分方程的渐近稳定性

给出了D算子中立型随机泛函微分方程的随机渐近稳定性的充分条件,推广了文[1]中相应的结果。     

金融衍生证券定价理论进展评述

准确地为金融衍生证券定价是金融交易市场规避风险的迫切需要，Ｂｌａｃｋ－Ｓｃｈｏｌｅｓ期权定价方程的基础上，研究了衍生证券的一般定价方法，对金融衍生证券的定价理论的研究内容，方法和结果作了初步的介绍，并对这一领域中存在的问题及最新研究方向进行了简单的综合评述。