具有时滞的非自治N一种群Lotka-Volterra竞争系统的灭绝准则

研究了具有时滞的非自治N一种群Lotka-Volterra竞争系统，利用Liapunov泛函改进了关于灭绝的准则。     

新疆药用地衣资源研究概况的初步探讨

地衣是一类独特的生物类群,它的药用价值非常高,已经引起了国内外科学家的重视.新疆现有地衣种类398种,其中不少具有药用价值.本文主要探讨新疆药用地衣研究概况,描述药用地衣的基本特征和地理分布区,为新疆药用地衣资源的开发利用提供科学依据.     

白刺属植物的化学成分分析及系统学意义

概述了白刺类植物研究简史，分析了白刺属5种植物和蒺藜科6种植物的化学成分，测了白刺属3种植物种子总氨基酸的组成，结果表明它与蒺藜科其他属的化学成分组成，氨基酸主要组成与含量和特征上有显著的差异，在一定意义上反映了起源上有一定的同源性和遗传上有一定的稳定性，并进一步支持将白刺属可以提升为白刺科（Nitrariaceae)。这对我国植物学家最近最出的中亚植物区的系统与演化研究和确定其系统位置的研究提供参考。     

溅射法制作的Fe-Al-O颗粒薄膜的磁化曲线及巨磁阻曲线的测定

用溅射法制作了不同的Fe-Al2O3颗粒薄膜，用样品振动型磁力计测定了磁化曲线和巨磁阻曲线，并对其进行了分析和讨论．     

Quasi-soliton generation in solid-state lasers with semiconductor saturable absorber

Recent advances in ultrafast, ultra-short solid-state lasers have resulted in sub-6 fs pulses generated directly from the cavity of Ti:sapphire lasers. The generation of extremely short pulses is possible due to the formation of a quasi-Schrodinger soliton. Our investigation is directed to the peculiarities of the transition between femtosecond to picosecond generation. We found that the above transition is accompanied by the threshold and hysteresis phenomena. On the basis of soliton perturbation theory, the numerical simulation studying two different experimental situations has been performed, the first situation corresponds to the study of the lasers field's parameters under variation of control parameters (dispersion or pump power), the second one is for continuous variation of control parameter within a single generation session. Physically it corresponds to not repeated laser session but the variation of control parameter when the pulse has formed already.     

哒嗪与噻吩共聚物的金属催化法合成及其表征

在二价镍配合物催化剂存在下,用3,6-二氯哒嗪与2,5-二溴噻吩格氏(G rignard)试剂共聚合成了哒嗪与噻吩共聚物,并利用红外光谱(FT-IR),核磁共振谱(1H-NM R)等对其结构和性能进行了表征.该合成方法所得共聚物的收率为75%,而且溶解于DM F、DM SO等普通溶剂.共聚物的紫外-可见吸收光谱(UV-v is)中在410nm处观察到最大吸收峰.用粉末X-射线衍射(XRD),热重分析(TGA)对所得聚合物的结晶性和热稳定性也作了初步探讨.     

新疆北部森林生态系统地衣植物生活型的初步研究

本文以新疆哈纳斯国家级自然保护区为例,初步研究新疆北部森林生态系统地衣植物生活型.将该地区的地衣植物生活型划分为石生固着型;地面固着型;树上附生型;藓丛附生型;草地附生型;旱生根着型等类型.其中,树上附着生种类非常丰富,占该地区地衣植物总种数的36.89%,其次为石生固着型占22.33%;草地附生型最少,只占该地区地衣植物种类的4%.从分析结果还可知,新疆哈纳斯国家级自然保护区地衣种类和生活型类型比较丰富,反映出该地区独特而复杂的地衣植物特点.     

创设数学思维最近发展区的几点措施

随着数学教学改革的不断深化，已有越来越多的数学教育工作者深刻地认识到，数学教学应是“数学思维活动的教学”．在数学教学中“创议数学思维最近发展区，是促进教学过程最优化的重要环节．”本文就如何创设数学思维最近发展区，谈几点体会．1揭示机会形成过程数学概念的教学应极大限度地给学生提供概念的提出背景、概念的抽象、概括过程，把概念的形成过程揭示在学生面前，为学生深刻理解概念实质创设思维的最近发展区．例1“奇、倡函数概念”一课．我们设计了如下教学程序：（1）提出问题背景．引导学生考虑函数y=x2和y=x3的图象的对称…     

Direct Numerical Simulation of Supersonic Turbulent Boundary Layer Flow

Direct numerical simulations of a spatially evolving supersonic flat-plate turbulent boundary layer flow with free Mach number M∞ = 2.25 and Reynolds number Re = 365000/in are performed. The transition process from laminar to turbulent flow is obtained by solving the three-dimensional compressible Navier-Stokes equations, using high-order accurate difference schemes. The obtained statistical results agree well with the experimental and theoretical data. From the numerical results it can be seen that the transition process under the considered conditions is the process which skips the Tollmien-Schlichting instability and the second instability through the instability of high gradient shear layer and becomes of laminar flow breakdown. This means that the transition process is a bypass-type transition process. The spanwise asymmetry of the disturbance locally upstream imposed is important to induce the bypass-type transition. Furthermore, with increasing the time disturbance frequency the transition will delay. When the time disturbance frequency is large enough, the transition will disappear.     

常微分方程形式的M/M/1排队模型的一个注

讨论动态Ｍ／Ｍ／１排队模型，运用半群理论证明了该模型存在唯一的正解，并研究了相应算子的谱特征．