黄连提取动力学模型研究

根据中药浸提机制和扩散理论,通过对黄连在乙醇环境中的浸提时间、温度、溶剂剂量、颗粒粒度与浸出有效成分浓度之间的关系进行优化,建立黄连提取的动力学模型。实验结果表明,在实验条件满足的前提下,动力学模型结果与实验结果较好地吻合。     

Zr53Cu18.7Ni12Al16.3过冷熔体的原子结构以及动力学性质的研究

本文采用第一性原理分子动力学方法,模拟了Zr53Cu18.7Ni12Al16.3过冷液体的原子结构,以及其对动力学性质的影响.通过对Al原子周围的偏对分布函数的分析,发现该过冷液体的原子结构可用以Al原子为中心的团簇来表征.这种局域结构稳定程度的空间不均匀性,导致了过冷液体的动力学在空间分布上的不均匀性,即出现速度较慢的原子.这种慢原子的出现,使得该过冷液体在过冷相区内发生动力学迟缓,从而抑制了晶化.     

实验及模拟研究两性疏水缔合聚合物增黏机理

两性疏水缔合水溶性聚合物具有良好的耐温、耐盐、耐剪切性能,在三次采油、酸化压裂等领域具有较大的应用潜力。室内合成了一种新型两性疏水缔合水溶性聚合物,分别研究了其水溶液在不同浓度、剪切和温度条件下的黏度变化情况。同时,利用耗散粒子动力学模拟(DPD)方法对其水溶液在不同浓度、剪切和温度条件下的水珠子扩散速率和疏水缔合聚合物的自组装结构进行了模拟研究。实验和模拟结果基本一致,利用耗散粒子动力学方法进一步证明了两性疏水缔合聚合物在水溶液的增黏机理和微观自组装结构。     

一种新型大过载飞行模拟器运动仿真分析

提出一种新型的基于绳牵引并联机器人技术的飞行模拟器,针对其大过载机动特性进行仿真分析。首先根据绳牵引并联机器人理论,设计了9根绳牵引具有6自由度的运动平台;通过建立平台动力学模型,设计了对干扰项进行补偿的前馈PD控制率;其中前馈项主要确保动态过程中绳索处于张紧状态。进一步给出了系统控制稳定性分析;并以大过载机动和单自由度俯仰振荡运动为例进行了数值仿真。分析结果表明,在大过载机动情况,瞬时正加速度超过4 g,平台位置能够迅速衰减并稳定;基于绳拉力前馈,可以避免绳索松弛,能够满足飞行员过载训练;俯仰运动也具有较好的跟踪特性。研究成果可为进一步分析工作空间、动态特性及控制稳定性等奠定基础,为绳牵引并联支撑的飞行模拟器设计提供指导与依据。     

脑循环Willis环控制方程

在循环Ｗｉｌｌｉｓ环定常流模型和脉动流模型的基础上，进一步讨论模型控制方程的求解方法，由于脑部血液循环的复合性，验证脑循环动力学模型和实验循环的相符程度有着重要的意义，通过求解集中参数模型的数据和临床数据的对比，验证了脑循环模型的正确性，并对时域状况进行了分析。根据脑循环集中参数模型对脑部血液循环模型的正确性，并对时域状况进行了分析，根据脑循环集中参数模型对脑部血液循环的代偿功能和其对单侧血液参数     

Transforming Self and Society: A "Critical Appreciation" Model

This paper sets out to uncover some relationships between reflection, discourse and action. By challenging and synthesizing some polemical arguments concerning the creation, maintenance, and transformation of self and society, a model of self-society dynamics that operates through reflection, discourse, and action is developed. The model of self-society dynamics brings together aspects of self-reflection and ideology-critique (explored in the paper), which it is suggested are required for any intervention (transformative action) to be grounded in locally meaningful ways. By creating a dialog community in which self- and group assumptions can be subjected to validation through discourse, it is proposed that a dynamic balance between individual needs and broader societal aims may be achieved. If individuals can be open to such discourse (i.e., they can become critically self-reflective), then it is argued that possibilities for achieving sustainable change will be significantly enhanced.     

带电聚合物刷的分子动力学模拟和研究

主要介绍通过分子动力学模拟来研究带电聚合物刷在水溶液和盐溶液中的结构性质，分别给出不同吸附密度下的单体密度，补偿离子分布图。通过模拟得到的刷子高度与通过新标度理论得到的高度值吻合的很好。验证了在渗透区，吸附密度对刷子的高度是存在影响的，并讨论了在同一吸附密度下，Debye长度对刷子结构的影响，刷子的高度随着Debye长度的增大而变大，进而达到通过盐离子浓度来控制刷子结构的目的。     

小级超越整函数Fatou分支的有界性(英文)

给出了级小于二分之一的超越整函数的Fatou分支有界性的几个充分条件.     

CONVERGENCE IN THE CHEMOSTAT MODELWITH DELAYED RESPONSE IN GROWTH

1.IntroductionThechemostatisalaboratoryapparatususedforcontinuouscultureofmicroorganisms.Itcanbeusedtostudycompetitionbetweendifferentpopulationsofmicroorganismsforagrowthlimitingsubstrate,andhastheadvantagethatcertainofthebiologicalparameterspresumedtoinfluencecompetitiveoutcomecanbecontrolledbytheeXPerimellter.TheglobalanalysesofthechemostatmodelwithMichaelis--MentenkineticsfornutrielltuptakeweregivenbyHsu,HubbedandWaltmanin[2]andHsuin[31.Undertheassumptionthatalltheparametersaredistinct…     

Spatio.temporal variations of the bacterioplankton community composition in Chaohu Lake,China

Despite considerable attention paid to Chaohu Lake in China,the dynamics of bacterioplankton community composition(BCC) on spatial and seasonal scales are poorly understood.In this study.water samples were collected from autumn 2006 to summer 2007 at five positions in Chaohu Lake with different trophic status.BCC of these samples was determined by both the PCR amplifieation of the 16S rDNA gene and the denaturing gradient gel electrophoresis (DGGE).The abundance and diversity of bacterioplankton communities at different sampling positions showed similar seasonal pattems.The BCCs in the samples varied substantially,and the pattern of changes indicated that the seasonal difiefence might have a significant impact on the BCC'S structure iU the lake.Canonical correspondence anal-ysis(CCA)on the DGGE patterns and physicochemical parameters indicated that the temperature and the levels of 5-d biochemical O2 demand(BODs),NH3-N,CODMn,total nitrogen,total phosphorous,and dissolved oxygen significantly influenced the BCC,and four of the seven variables were related to the level of eutrophication.Our results indicate that eutrophic status and season are the most inttu-ential factors in determining BCC in Chaohu Lake.