基于增量电导法的光伏最大功率跟踪的仿真研究

介绍了光伏电池模型的工程数学模型,并在MATLAB/SIMULINK环境下建立了光伏电池的工程仿真模型。为了能够实现光伏电池的最大功率输出,本文介绍了最大功率跟踪的原理和方法。使用增量电导法实现最大功率点跟踪。并在MATLAB/SIMULINK环境下搭建光伏发电系统的仿真模型进行了仿真。仿真结果表明,搭建的光伏电池波形以及最大功率跟踪控制的仿真结果证明了可行性,可以用于光伏发电系统的仿真研究。     

Rethinking fat as a fuel for endurance exercise

Abstract

A key element contributing to deteriorating exercise capacity during physically demanding sport appears to be reduced carbohydrate availability coupled with an inability to effectively utilize alternative lipid fuel sources. Paradoxically, cognitive and physical decline associated with glycogen depletion occurs in the presence of an over-abundance of fuel stored as body fat that the athlete is apparently unable to access effectively. Current fuelling tactics that emphasize high-carbohydrate intakes before and during exercise inhibit fat utilization. The most efficient approach to accelerate the body’s ability to oxidize fat is to lower dietary carbohydrate intake to a level that results in nutritional ketosis (i.e., circulating ketone levels >0.5 mmol/L) while increasing fat intake for a period of several weeks. The coordinated set of metabolic adaptations that ensures proper interorgan fuel supply in the face of low-carbohydrate availability is referred to as keto-adaptation. Beyond simply providing a stable source of fuel for the brain, the major circulating ketone body, beta-hydroxybutyrate, has recently been shown to act as a signalling molecule capable of altering gene expression, eliciting complementary effects of keto-adaptation that could extend human physical and mental performance beyond current expectation. In this paper, we review these new findings and propose that the shift to fatty acids and ketones as primary fuels when dietary carbohydrate is restricted could be of benefit for some athletes.     

加拿大安大略省健康与体育课程标准中德育内容的分析与启示

通过对加拿大安大略省健康与体育课程标准中的德育内容分析和研究发现,安大略省的德育深深地渗透在健康与体育课程内,其特点主要包括：其一,安大略省的健康与体育课程中德育内容要求是发展性的,即不同年级阶段,德育内容的要求重点不一样。其二,安大略省健康与体育课程的德育内容与学生的生活结合紧密,且紧紧融入在学生的学习和生活中。其三,安大略省健康和体育课程中的德育内容要求主要是通过学生“doing”的方式,让学生学习道德品质。其四,安大略省健康与体育课程中的德育内容要求从学校拓展到家庭、社区乃至整个社会,而不只是禁锢在班级内。其五,安大略省健康与体育课程强调培养学生的思考力和判断力。安大略省的健康与体育课程标准中的德育渗透对我国体育与健康课程教育教学中的德育教育具有重要的启示。     

新媒体在高校学风建设中的作用及对策探析

随着高校扩招计划的实施,高校学风建设受到了前所未有的挑战,加强学风建设已经成为各高校的重要工作之一。随着科技的发展,新媒体已经迅速发展并对高校的学风建设也起到了积极和消极的作用。新媒体在高校学风建设中起到丰富学习资源、提供交流平台、提高学习效率、改变学习方式、反馈学习信息等积极作用的同时,在信息质量、分散学习精力、产生学习惰性等方面又产生了一定的消极作用。因此,高校应该针对自身特点从学生媒介素养教育、搭建校园平台、扩大应用渠道、加大监管力度等方面对新媒体进行规范使用,使新媒体能够更好地作用于学风建设。     

项目教学法在“金属材料热处理”课程中的应用

为提高教学效果,培养学生自主学习兴趣和能力,采用项目教学法对本文“金属材料热处理”课程进行全新的课程设计和教学实践。本文介绍了项目教学法的实践经验和实施过程中应注意的几个关键问题。总之,项目教学法能够有效提高材料类专业的“金属材料热处理”课程的教学效果,值得进一步推广。     

基于结构方程的林木生物质能源产业链外部驱动力研究

基于产业链演化过程,引入PEST理论,运用结构方程模型探讨林木生物质能源产业链的外部驱动力及其影响程度。结果表明:现阶段产业政策和行业技术是影响林木生物质能源产业链扩展的主要驱动力,区域环境负荷在一定程度上对产业链的扩展产生正向影响,产业需求的拉动效应还未突显。在深入分析林木生物质能源产业链外部驱动力的基础上,为如何促进该产业发展提出相应的政策建议。     

科学数据管理与共享领域作者合著网络研究

运用社会网络分析法,对科学数据管理与共享领域的作者合著情况进行可视化展示及分析。从合著网络的密度、中心性、凝聚子群以及核心-边缘等角度做实证研究,揭示该领域部分高产作者的一些特征,发现合著网络中紧密的学术团体,评价学者在合著网络中的地位。     

The emergence of a knowledge-based theory of internationalisation

This paper charts the development of the knowledge-based theory of internationalisation, driven particularly by early research at the University of Uppsala, led by Sune Carlson. Information and knowledge, allied with an interest in the associated effect on risk and uncertainty, were components of a process perspective. Its essence was a focus on the restraining effects of a lack of knowledge as decision-makers contemplated international market entry or expansion requiring a commitment of resources in various forms, in different types of foreign operations (such as exporting, licensing and foreign direct investment). Lack of knowledge of a prospective foreign market (of its characteristics, culture, ways of doing business) was seen to create uncertainty so that firm decision-makers would be less prepared to commit resources. This situation was bound to change as a firm conducted operations in the foreign market and acquired experiential knowledge (learning by doing), which made the foreign market less of a mystery, in the process lowering uncertainty. As the learning process unfolded, and expanded opportunities were perceived, at some stage the firm might be prepared to undertake additional commitments to the foreign market. Empirical research at Uppsala, and in Finland, had shown a pattern of gradual expansion of foreign commitments by internationalising firms. In terms of theoretical development, a key step was relaxation of the assumption of perfect knowledge used in economics (not without critique), noted by Don Lamberton in 1974. Following the development of internationalisation theory in the 1970s, there was a range of extensions to the basic theory, such as the role of networks, the nature of inward–outward connections, and the need for knowledge to pass over language hurdles in the process of international transmission – within and outside the firm. In one sense, the internationalisation of companies was a perfect research site for an exploration of the role of information and knowledge in firm behaviour, given the additional exigencies of the diverse and demanding information environment that is the international arena.     

Evaluation of Oxidative Stress and hsCRP in Polycystic Ovarian Syndrome in a Tertiary Care Hospital

PCOS is a heterogeneous endocrine disorder with diverse clinical presentation. Oxidative stress plays a key role in the pathophysiology of this disease. Serumhigh sensitive C-reactive protein (hsCRP), a marker of chronic low grade inflammation, is indicative of future development of cardiovascular disease. Our aim is to evaluate the oxidant status and hsCRP levels in PCOS. The study involved 61 cases and 61 controls in the age group of 18–40 years diagnosed with PCOS. Erythrocyte malondialdehyde (MDA), superoxide dismutase (SOD), serum hsCRP, gonadotrophins, thyroid stimulating hormone, prolactin, glycemic status and lipid profile were estimated. Erythrocyte MDA (p < 0.001), SOD (p = 0.007) and serum hsCRP (p < 0.001) were significantly elevated in PCOS patients than controls. Oxidative stress is present in women with PCOS along with elevated hsCRP.     

The study of systems and methods for scientometric analysis of scientific publications

This paper provides an overview of the methods and systems that are applied for scientometric analysis of scientific publications. Methods to identify promising research directions are described. The results of an experimental study aimed at determining the directions of scientific research within the subject area of “regenerative medicine” by using various methods are presented. Conclusions are made about the prospects and shortcomings of the applied methods. Directions for further research are proposed.