师生教学信息不对称问题浅析

教师在品德、知识和能力等信息方面与学生存在不对称现象,是教师成为合格教师的基本条件。建立学习型组织、实施知识管理工程,克服信息经济环境中教师与学生正在缩小的不对称差距程度,给学校教育注入持续活力。     

Mathematical Analysis of Energy Efficiency in IEEE 802.11 DCF

The standardized IEEE ,802. II distributed coordination function （ DCF） provides a contention-based distributed channel access mechanism for mobile stations to share the wireless medium. However, when stations are mobile or portable units, power consumption becomes a primary issue since terminals are usually battery driven. This paper proposes an analytical model that calculates the energy efficiency of both the basic and the RTS/CTS access mechanisms of the IEEE 802. II protocol. The model is validated with simulation results using NS-2 simulation package. The effects of the network size, the average packet length, the initial contention window and maximum backoff stages on the energy efficiency of both access mechanisms are also investigated. Results show that the basic scheme has low energy efficiency at large packet length and large network size, and depends strongly on the number of stations and the backoff procedure parameters. Conversely, the RTS/CTS mechanism provides higher energy efficiency when the network size is large, and is more robust to variations in the backoff procedure parameters.     

用热力学浅析几个“反常”问题

通过对化学几个“反常”问题的浅析,说明热力学是一种非常有用的理论工具.     

掺杂剂与基质材料能量匹配的红色有机发光二极管

1　Introduction　Organiclight emittingdiodes(OLEDs)haveattract edconsiderableattentionduetoitsgreatpotentialinefficiency ,low voltage ,large area ,lightweight ,andfull colorflat paneldisplays[1,2 ] .Forfull colordis plays ,itisnecessarytohaveefficientred ,green ,andblueemitterswithappropriatechromaticity .Bycom parisonwiththehighperformanceofblueandgreenOLEDs ,theperformanceandpurechromaticityofredOLEDsarestillrelativelypoor .UsuallyredOLEDsareimprovedbydopingreddyesintohostmaterialswit…     

试论高职教师的教学能力

培养高素质的学生，必须有一支高素质的教师队伍，高职教师的教学能力对教学质量的影响较大，本对高职教师的应具有的教学能力进行了探索。     

《论语》语句疏解

因《论语》为语录体，其编纂“不为义例”，转换灵活，一些语句的注疏、理解存有歧见。本文辑录“学而时习之，不亦说乎？有朋自远方来，不亦乐乎？人不知而不愠，不亦君子乎”等四个语段，着眼于整体，从话题、语意的一致性和内在逻辑联系等方面加以疏解，以求通惬，追近原意。     

"熵"的科学定义

“熵”是热学中一个极其重要的基本概念，追溯它的起源，从物理定义的“完备性”要求，对“熵”从宏观到微观，从“定性”到“定量”分别进行了定义。     

解读《普通高等学校图书馆规程(修订)》的意义

《普通高等学校图书馆规程(修订)》的意义表现为突出了图书馆信息服务的地位，充实了献资源建设的意义，强调了读服务体系的建立，明确了科学化管理的要求，提高了专业人员素质结构标准，加大了图书馆经费保障力度等六个方面。     

电子类教学仪器的抗振防振设计

对电子教学设备的抗振从理论和实践上进行了探讨，并介绍了电子类教学设备的抗振设计原则和方法。     

如何正确理解和分析摩擦力

就高中学生在学习摩擦力概念易出现的三方面误区谈一谈高中物理教学过程中应如何引导学生正确理解摩擦力的方向、大小以及做功引起能的转化.