非均匀强化塑性模型中混凝土的三参数统一强度本构关系

介绍了三参数统一强度理论和非均匀强化塑性模型,并利用非均匀强化塑性模型,对三参数统一强度理论进行推导,得出了混凝土在强化过程中的弹塑性本构关系.当参数取不同的值时,该本构关系能适用于不同的材料。     

不同光照强度对薇甘菊幼苗生长和形态的影响

比较了生长在不同光照强度下的薇甘菊 (Mikainamicrantha) 幼苗的生长型。结果表明 :苗高、节间长、比叶面积、叶面积比、总叶面积、净同化速率、支持结构生物量比、根生物量比和根冠比随着光照强度的变化而改变 ;然而 ,比茎长、比叶柄长、总生物量、相对生长速率和叶片生物量比却保持相对的稳定。说明薇甘菊幼苗对不同的光强梯度具有不同的可塑性和适应性。     

青春期少年心机能可塑性的研究

本文采用运动训练、减量训练、停止训练相结合的实验方法,通过阻抗心动图的测定,分别对A、B两组青春期少年的左心功能变化进行了纵向研究.结果发现经过3个月的定量训练两组少年的心脏工作能力均有显著提高,且A组减量训练一个月后仍保持较高的水平,但B组停训一个月后则表现出明显的回降.由此显见,青春期少年的心脏对运动刺激有着较高的敏感性和机能可塑性,这对正确指导青少年的体育锻炼和运动训练具有重要的理论和实践意义.     

Age Factor in Second Language Acquisition

In the second language acquisition, the study focus of linguistics is the influence of age factors which has always been considered as one of the most controversial issues. Some experts hold that the younger the better and would get good competence to learn language well, meanwhile others believe that adult have more strong motivation and competence.Based on the Brain Plasticity Theory and the Critical Period Hypothesis, and the intention of this thesis is to reveal such a hypothesis that the younger the learner who starts to learn a second language, the greater performance that he will achieve like a native does, through the comparative research between children and adults. The subjects are 100 Chinese learners who begin learning at different levels and ages. According to the results of integrated scores and a collection of the data in the questionnaire, an analysis show that the results acquired would be consistent with the hypothesis.The intention of this research is not only to argue which is better, earlier or later, but also an trial, through investigation and study, to provide some insights and suggestion to the existent issues, especially the children second language education and college English study in China.     

探究年龄对二语教学的影响

该文强调年龄是影响第二语言习得的关键因素。以Penfield和Roberts的大脑弹性理论以及Lenneberg的关键期假设作为基础,该文目的旨在研究年龄是如何影响第二语言习得及体现在哪些方面。此外,为了提高外语学习效率,有必要对比分析儿童、青少年和成年人在学习第二语言过程中的优缺点。该文通过对他们习得二语过程中所表现出的特点进行分析,为我国英语教育提供一些启示。     

Tai Ji Quan,the brain,and cognition in older adults

The relationship between physical activity (PA) and cognition has received much attention recently. While evidence of improved cognition following PA has consistently been observed, the majority of studies have spotlighted aerobic exercise and the effects of other modes of PA, such as Tai Ji Quan, on cognition have received limited attention. This article provides a brief review of the literature concerning the influence of Tai Ji Quan on cognition in older adults, including those with intact cognition and those with cognitive impairment. In addition, this review proposes potential mechanisms (cardiovascular fitness, motor fitness, movement coordination, social interaction, and meditation statuses as well brain structure and function) evaluated from a neuroimaging perspective that may explain the Tai Ji Quan–cognition relationship. Finally, we present suggestions for future research. In conclusion, Tai Ji Quan, with its multi-faceted characteristics, shows promise as a mode of PA for enhancing cognition, as well as brain health, in older adults. Based on the findings in this review, further exploration of the effects of Tai Ji Quan on cognition in older adults is warranted.     

Different responses of two Mosla species to potassium limitation in relation to acid rain deposition

The increasingly serious problem of acid rain is leading to increased potassium (K) loss from soils, and in our field investigation, we found that even congenerically relative Mosla species show different tolerance to K-deficiency. A hydroponic study was conducted on the growth of two Mosla species and their morphological, physiological and stoichiometric traits in response to limited (0.35 mmol K/L), normal (3.25 mmol K/L) and excessive (6.50 mmol K/L) K concentrations. Mosla hangchowensis is an endangered plant, whereas Mosla dianthera a widespread weed. In the case of M. hangchowensis, in comparison with normal K concentration, K-limitation induced a significant reduction in net photosynthetic rate (P _n), soluble protein content, and superoxide dismutase (SOD) activity, but an increase in malondialdehyde (MDA) concentration. However, leaf mass ratio (LMR) and root mass ratio (RMR) were changed little by K-limitation. In contrast, for M. dianthera, K-limitation had little effect on P _n, soluble protein content, SOD activity, and MDA concentration, but increased LMR and RMR. Critical values of N (nitrogen): K and K:P (phosphorus) ratios in the shoots indicated that limitation in acquiring K occurred under K-limited conditions for M. hangchowensis but not for M. dianthera. We found that low K content in natural habitats was a restrictive factor in the growth and distribution of M. hangchowensis, and soil K-deficiency caused by acid rain worsened the situation of M. hangchowensis, while M. dianthera could well acclimate to the increasing K-deficiency. We suggest that controlling the acid rain and applying K fertilizers may be an effective way to rescue the endangered M. hangchowensis. Project supported by the National Natural Science Foundation of China (No. 30570113) and the Research Fund for the Doctoral Program of Higher Education (No. 20060335008), China     

从神经科学到教育研究

教育应重视大脑发展规律并根据相关规律科学实施教育活动。但囿于人类对大脑及其活动探讨本身的成果局限,基于大脑活动规律而设计的教育实践及理论略显空泛。近年来,此现状大有改观。笔者从生理方面、语言习得、第二语言习得和阅读、计算四个方面介绍了神经科学领域关于教育的最新研究成果,向教育研究者和教师、家长提供教育活动背后的“被教育者”的认知神经活动过程,以期思考如何提高教育实践的质量和有效性。     

运动技能学习的神经机制

运动技能学习是以神经活动为基础的生理、心理过程。近年来 ,关于运动学习记忆在神经通路和突触可塑性方面的研究成果揭示了运动技能学习的神经基础。本文综述这方面的研究成果并讨论了它们的实践指导意义。     

估计被锁定流通股数量的一种定量分析方法及其实证研究

从股票市场的量价规律出发提出股票均衡价格、股价塑性等新概念，使用计量经济学方法建立包含高频交易数据的股价塑性模型，对模型进行推导，提出一种识别被锁定流通股数量的定量分析方法，并基于三支问题股进行相应的实证研究。实证结果表明该方法计算出的被锁定流通股数量与历史相符合，该方法可行。