90年代中国文学漫议

2 0世纪 90年代文学 ,虽然极大地丰富和发展了“五四”以来中国文学的现代性特征 ,但并不意味着中国文学现代性的结束 ,而只意味着它的尚未完成与进一步展开。一百多年来 ,作为心灵呼吸、挣扎和创造的特殊方式 ,文学基本上延续着晚清以来无数前辈的努力包括他们的局限 ,用自己的方式体现着现代中国的天命。     

等价电子组态nlN光谱项的推求法

从等价电子组态的"自旋因式化"出发,导出了nsN～nhN组态的Lα、Lβ取值规则,给出了推求等价电子组态光谱项的简易方法.     

中国南方岩溶地区脆弱的生态环境及石漠化过程

中国南方岩溶地区分布有面积广泛的碳酸盐岩,发育多种岩溶地貌。由于该地区的特殊地质、水文、气候等自然因子的影响,其岩溶生态环境非常脆弱,环境容量低,敏感度高,抗干扰能力弱。当人类对森林进行破坏使森林的“生物泵”作用消失后,引发出一系列的生态问题：岩溶生态环境开始恶化,植被走向逆向演替等。最后出现大面积的石山,发生石漠化现象。可见,森林在岩溶生态系统中的作用是十分重要的,是影响岩溶生态系统的关键因子。     

利用Maple的Student函数包学习微积分的尝试

Maple是当今最流行的数学软件之一,其附带的Student函数包对微积分的教与学都很有帮助,本文作者在将其用于微积分教学方面做了一些探索．     

人文工学维面的"传媒分众化"问题 --感性传达对策研究预案

随着我国在“WTO”中的深入,传媒身份的双重性和其跨学科超行业的多面性,决定了网络背景下打造我国新闻传媒“航母”工作的交叉综合性。本基于当代认知分析方法论及已有研究,从人工学感性协同机理切入,对传媒分众化问题在“第三种途径”上提出了解决方案。     

开关电源的电压波形及其参数分析

开关电源已是当今二次电源的主要发展方向,在开关电源的分析与设计中,对开关工作时所形成的电压波形及其参数的分析是致关重要的。为了分析开关电源的工作特性,研究了开关电源的电路模型及电压波形的形成过程,针对分析开关电源的电压波形及其参数,提出了一套“辅助补偿”算法。基于这套算法,对开关电源的电压波形及其参数进行了理论分析和计算机仿真。仿真结果表明了这套算法的可行性和先进性。     

Pre-selecting young bulls before progeny-testing with marker-assisted BLUP

Suppose that a QTL affecting milk production trait or dairy cattle has been identified,and the relative distances between the QTL and the markers are hnown without error.The relative efficiency of pre-selection of young bulls before progeny-testing with marker-assisted BLUP(MBLUP) over conventional progeny-testing(i.e.random selection before progeny-testing)for five generations was studied using Monte Carlo simulation.Different numbers of QTL alleles(two or infinite),initial frequencies of the favorable QTL allele(0.1 and 0.5,when the QTL has two alleles),distances between the adjacent markers(5 cM or 20 cM),and ratios of the QTL variance to the genetic variance(10%,25%,and 50%)were considered in the simulation.The results showed that the relative efficiency of MBLUP was higher when the marker distance was 5 cM than that when the distance was 20 cM.The larger the QTL alleic effect,the lower the MBLUP efficiency.The relative superiority of MBLUP was higher when the QTL had two alleles and the frequency of the favorable QTL allele was low in the base population.The relative superiority of MBLUP decreased with th progress of generation in all cases and the decreasing rate was getting higher with the increase of marker density and QTL effect.     

树木成长过程的计算机仿真--人工生命的一个问题

本文从已有的原始模型开始,考虑了周围环境对树木生长的影响.即设定了一些随机变量加入到原始模型中,模仿环境中诸如阳光、空气和水分等因素对树木生长的影响.除此,本文同时展示了树木及地下树根部分协同生长的情况.在建模的同时,应用了Hansrudi Noser开发的Lworld.exe软件实现了整个模型的可视化.     

Coupling and feedback between iron and sulphur in air-sea exchange

Iron in surface seawater has been demonstrated to be the limiting nutrient factor for primary productivity in certain oceanic regions where other major nutrients are abundant[1—5]. The available Fe to the phytoplankton in seawater is related to the uptake of carbon dioxide through the ocean and, in turn, to the global greenhouse effect[6—11]. Recent reports showed that the available Fe in the seawater is closely correlative to nitrogen fixation in the ocean[12—17]. Understanding which Fe s…     

Experimental investigation of parallel optical data storage using pyrrylfulgide photochromic material

The optical storage characteristics of a new kind of organic photochromic material棗pyrrylfulgide were experimentally investigated in the established parallel optical data storage system. Using the pyrrylfulgide/PMMA film as a photon-mode recording medium, micro-images and encoded binary digital data were recorded, readout and erased in this parallel system. The storage density currently reaches 3?107 bit/cm2. The recorded information on the film can be kept for years in darkness at room temperature.