三维蜂穴Ising模型的磁矩

本文用有效场理论研究了自旋为1／2的三维蜂穴结构的Ising模型的磁矩。     

Mode selection mechanism and magnetic diffusivity in a non-axisymmetric solar dynamo model

The generation of solar non-axisymmetric magnetic fields is studied based on a linear α²–Ω dynamo model in a rotating spherical frame. The model consists of a solar-like differential rotation, a magnetic diffusivity varied with depth, and three types of α-effects with different locations, i.e. the tachocline, the whole convective zone and the sub-surface. Some comparisons of the critical α-values of axisymmetric (m = 0) and longitude-dependent modes (m = 1,2,3) are presented to show the roles of the magnetic diffusivity in the problem of modes selection. With the changing of diffusivity intensity for the given solar differential rotation system, the dominant mode possibly changes likewise and the stronger the diffusivity is, the easier the non-axisymmetric modes are excited. The influence of the diffusivity and differential rotation on the configurations of the dominant modes are also presented.     

基于正规形法的结冰飞机着陆阶段非线性稳定域

结冰导致飞机飞行包线缩小、对飞行安全产生严重威胁,研究结冰后飞机非线性稳定域对边界保护系统的设计和飞行安全的提高极其重要。以某型运输机为研究对象,考虑飞机非线性气动特性建立飞机纵向非线性模型并进行增稳控制补偿设计;然后通过流形和正规形理论刻画结冰飞机纵向非线性稳定边界并得到稳定边界的解析表达式,通过仿真的手段验证了正规形理论确定的稳定边界和解析表达式的有效性和准确性。最后,分析了飞机着陆过程中,结冰因子对结冰飞机稳定域的影响以及结冰飞机发生事故的机理。研究结果表明,轻度结冰使飞机非线性稳定域缩小;重度结冰导致飞机稳定性发生改变;在未察觉飞机结冰的情况下,飞行员的常规操纵会使飞行状态超出结冰飞机的非线性稳定域、导致飞行事故。研究结果可为飞机结冰后的边界保护提供一定的参考。     

Benefits and challenges of voluntary contribution to GEOSS

The vision of the Global Earth Observation System of Systems (GEOSS) is the achievement of societal benefits through voluntary contribution and sharing of data, metadata and products at no or minimum cost. Such undertakings, where contribution provides positive externalities, benefiting contributors and non-contributors alike, are often described as ‘social dilemmas’, usually resulting in small levels of voluntary contribution. We investigate the benefits and challenges of voluntary contribution to GEOSS, surveying economic and game theoretic literature and examining how the concepts of social dilemmas apply to the provision of GEOSS. We conduct an exploratory survey among individuals involved in the Group on Earth Observation (GEO) to understand their perception of voluntarily contribution. Even though contribution to GEOSS was perceived as rather low, e.g. because of a perceived lack of funds, commitment or organization, survey respondents also perceived many (exclusive) benefits of contribution, e.g. networking, visibility for their work or collaborating with motivated individuals. To increase participation, respondents suggested increasing financial support and raising awareness of GEOSS. We conclude that communicating the efficacy of individuals' contributions, the personal benefits of contribution and strengthening of group identity and knowledge about fellow participants' work can constitute incentives for future voluntary contribution. This could be facilitated by an externally established institution providing a framework for cooperation, or by institutions, agreements or frameworks agreed upon by contributors themselves.     

苏-27飞机"眼镜蛇"机动的机理和操纵

详细地介绍了苏-27飞机"眼镜蛇"机动的运动特点和完成条件,典型的"眼镜蛇"的过失速机动驾驶要领、动作特点和影响因素,可供从事过失速飞行实验,战术机动动作研究的技术人员和飞行人员参考。     

分级网络计划的动态管理原理及其软件实现

网络计划技术是一种应用广泛的管理技术，但如何实现网络计划的动态管理理则是一个长期未能解决的问题，本文在对该问题进行深入研究的基础上，提出了一个两级网络动态控制模型，并详细论述了它的实现原理，根据该原理研制了网络计划动态管理软件，文中就有关理论，方法和软件实现进行了阐述。     

企业文化定量评价方法的研究

针对目前评价企业文化的方法在定量分析方面的不足，应用模糊数学理论建立了一个企业文化模糊综合评价模型是一个企业文化产例加以说明，为企业家决策提供科学依据。     

基于灰色聚类理论的工业航空区域化分布研究

通用航空在服务于国民经济发展方面具有重要的战略意义,而为工业生产建设提供航空飞行服务的工业航空作业是通用航空的重要组成部分,其作用尤为突出.结合中国不同地区自身的地理环境、经济发展等差异,研究各地区对工业航空的需求分布,可为国家制定相关政策、引导市场发展提供了借鉴依据.由于中国长期以来对通用航空缺乏有效监测,各类统计信息不完善,本文基于灰色星座聚类理论,从理论上探讨各地区对工业航空作业的主导需求,具有重要意义.     

从原型范畴理论的角度谈if条件句

英语if条件句是一个句法结构,是语义关系和语用环境都很复杂微妙的语言现象,也是英语教学中的难点之一.本文以原型范畴理论为基础,对条件句范畴进行分类和分析,认为真正条件句是原型成员,非真正条件句是非原型成员,意在推动认知语言学理论和条件句的研究和教学的结合,说明原型范畴理论对英语条件句的范畴化过程有着较强的解释力.     

从焦点理论看“日语汉字缩略语”

在目前的＂日语汉字缩略语＂研究中,缩略语的构词形式和音节特征被广泛提及,但是对词素的研究并不多见。从焦点理论角度出发,本文采用推断统计法对522条常用＂日语汉字缩略语＂进行统计,并分析日语汉字缩略类型及其缩略规律。分析结果显示,在日语汉字缩略语形成过程中,原词的首字就是缩略语的首选对象,即缩略语的信息焦点来自原词的第一个词素。