通过计算确定地线的埋设方法

接地装置的接地电阻有严格的要求,不同埋设地线的方法会产生不同的接地电阻.通过计算表明,水平埋设LCP长效地线产生的接地电阻最小.     

PPP协议及连接剖析

PPP协议(Point-to-Point Protocol)是目前广域网上应用最广泛的协议之一，PPP是为在同等单元之间传输数据包而设计的链路层协议。本文通过对PPP协议进行剖析，分析了PPP的基本原理，并简单介绍了PPP的连接过程。     

The Large Context Problem (LCP) Approach

This article traces the development of a contextual approach to the teaching of science (physics) subsequently called the Large Context Problem (LCP) approach. This approach is based on the general observation that learning could be well motivated by a context with one unifying central idea capable of capturing the imagination of the students. The design and the placing of the LCP is followed by a detailed discussion of the contexts of inquiry (as we find it in Newtonian physics) that attempts to give the contextual activities found in the LCP a sound theoretical backing. However, the contextual base must also be informed by the findings of constructivist learning theories as well as the history of science. Moreover, thought experiments (TEs) are considered an important aspect of science (physics) teaching and three kinds of TEs are discussed. All these ideas are summarized for a quick overview in a table called “Levels of investigation for scientific inquiry.”