Numerical computations of the flow in a finite diverging channel

The flow in a finite diverging channel opening into a large space and resembling the experimental prototype of Putkaradze and Vorobieff （2006） was numerically investigated. The effects of the Reynolds number, initial condition, intersection angle, length of the wedge edges, and the outer boundary condition were examined. The numerical results showed that the flow in the wedge undergoes a change from symmetrical flow to unsymmetrical flow with a weak backflow, then a vortical （circulation） flow and finally an unsteady jet flow as the Reynolds number is increased for an intersection angle of 32° and a wedge edge of length 30 times the width of the inlet slit. For the unsteady flow, the jet attached to one side of the wedge constantly loses stability and rolls up into a mushroom-shaped vortex-pair near the outlet of the wedge. As the intersection angle is increased to 50°, a stable jet flow is observed as a new regime between the vortex and unsteady regimes. Both the intersection angle and the wedge length have negative effects on the stability of the flow, although the effect of the wedge length on the critical Reynolds number for the symmetry-breaking instability is not pronounced. The outer boundary condition was found not to affect the flow patterns inside the wedge significantly. At a certain Re regime above the onset of symmetry-breaking instability, the flows evolve into steady state very slowly except for the initial stage in the case of decreasing flow flux. Two different solutions can be observed within the normal observation time for the experiment, providing a possible explanation for the hysteresis phenomenon in the experiment.     

言语行为转喻和名词动用现象研究

在认知语言学看来,转喻和隐喻一样是人们的一种思维方式,这样的思维方式反映在语言的表达上。本文采用认知语言学关于言语行为转喻的观点,研究名词动用现象。本文认为,名词动用实质是言语行为转喻。     

深圳市“图书馆之城”统一服务平台构建与实施

通过对深圳市通借通还业务问题的梳理、统一服务平台建设的必要性分析引出深圳市公共图书馆界目前正在进行的图书馆之城统一服务平台建设和实施即统一技术平台搭建、读者库和书目库的合库、服务规则统一等一系列具有开创性工作,并对深圳市图书馆之城统一服务平台建成后的前景进行展望。     

基于统一资源管理的图书馆知识服务

本文从图书馆知识服务的现有模式出发,分析其局限性,并提出基于统一资源管理的知识服务模式,包括资源整合、知识搜索、个人知识门户、隐性知识挖掘等方面。该模式有助于图书馆元数据管理系统的建立及用户体验与忠诚度的提升。     

Using Mixed-Methods to Examine Teachers' Attitudes to Educational Change: The case of the Skills for Life strategy for improving adult literacy and numeracy skills in England

This paper reports on a longitudinal study that examines how a national reform introduced in England in the field of adult literacy, language, and numeracy is affecting teachers. The paper focuses on the use of a mixed methodology to explore teachers' attitudes to the reform and how these change over time. The quantitative strand includes the construction and use of a Likert-type instrument for measuring the attitudes of a panel of 1,500 teachers. The qualitative strand builds on the quantitative results and includes focus groups and in-depth interviews with a subsample of teachers in the panel. As the study is still in its initial phase, the purpose is not to present findings, but to discuss how quantitative and qualitative evidence can be combined in evaluation research.     

系统函数与时域特性的可视化仿真平台设计

系统函数是信号与系统课程中一个非常重要的概念,它在系统分析中占有重要地位,系统的时域特性是系统的重要特性之一,它取决于系统函数的零、极点分布。利用仿真软件Matlab中GUI设计了系统函数与时域特性的可视化仿真平台,它直观形象地把系统函数与时域特性之间的关系表现出来,加深了学生对此重要内容的理解和掌握,并激发了学生的学习兴趣。     

开放大学移动图书馆建设浅议

移动图书馆的建设作为一所现代开放大学信息化建设水平、科研基础和资源建设等方面的重要标志,是开放大学建设发展的一项公共服务基础.在移动图书馆建设中,馆藏数字资源移动化、资源利用率的提高、跨库资源统一查询、地域及网段限制的突破、实现多终端样式的自适应及同一版式的全文阅读等问题是移动图书馆需要解决的关键问题.     

展会复杂域探讨

展会在特定的场域内聚集着组织、人、物、信息等,是复杂的多系统交织的社会活动,其形成依靠本地产业根植性,并形成特定的流动性,而其中运作机制需要生成、涌现、切近,从而产生大量的商机、品牌传播等社会现象。尽管展会是一种市场行为的自组织,但是需要进行适当的控制,需要从吸引子的依托性营造,自上而下的规则制定,自下而上的创新,还需要各组织的自律控制。     

基于SNA的我国期刊论文客家研究主题分析

社会网络分析方法为学科和领域的综述研究提供了一个新的研究方法,通过社会网络分析进行分析,可以从社会网络的视角了解我国客家研究类期刊论文在研究主题的现状和特点。研究结果揭示,我国期刊论文中的客家研究主题较松散,研究不是非常成熟和深入;客家山歌、客家文化等研究主题是我国期刊论文中客家研究的热点;高频词共词网络存在126个1-派系众多但规模小,表明期刊论文中的客家研究广度还不够,但在客家山歌、客家文化、赣南客家、客家民系、客家人等方面的研究比较深入。     

THE PROPER COPY

Efforts to make (and keep) knowledge public have provided a powerful counter-model to the recent expansion of exclusive intellectual property rights in such arenas as information technology, digital media, biological research, and pharmaceutical access. While sympathetic to the impulse to counteract the new ‘enclosures’ with knowledge made public, this essay critically interrogates some of the constitutive limits – in fact, the constitutive outsides – to these counter formulations. Paying particular attention to how public domain initiatives, like their strict intellectual property counterparts, also police the line between the proper and the improper copy, I argue that mechanisms for keeping knowledge public do not just circle the wagons against the predations of the Monsantos and Microsofts of the world. In their rhetorical and normative commitments to the proper copy, they also risk reproducing some of the same constrictions and exclusions that we tend to associate with (privatized) acts of enclosure itself. I explore this argument first in reference to creative commons and copyright, which can reproduce a strong ideological commitment to improvement – ‘innovation’ or ‘creativity’ – against the mere copy. What is the cost, I ask, of making the idea of improvement the price of admission not just to intellectual property claims, but to participation in newly ‘democratic’ public and common spaces of knowledge production? Second, I look to global pharmaceutical politics – specifically, regulatory efforts to improve access to cheaper copied and generic drugs in Argentina – to raise questions about the public domain's normative place in the continued expansion and harmonization of intellectual property regimes in the so-called global South. Together, these discussions suggest how the public domain and the commons, like their IP counterparts, can rhetorically and normatively expand and be secured against the improper copy.