汇川H2U系列PLC之间RS-485通信的实现

主要研究了汇川公司H2U可编程控制器(PLC)的通信技术,实现了两个H2U系列PLC之间基于RS-485的通信,并详细介绍了PLC之间通信的硬件连接方式、通信串口参数配置、触摸屏画面的设计以及程序实现。所讨论的方法已在采用H2U PLC及辅助设备组建的"运动控制系统"课程的教学实验平台上进行了验证,可以拓展应用于多台H2U PLC之间以及其他设备与H2U PLC之间的RS-485通信实现,对工程应用具有一定的借鉴意义。     

数字图书馆互操作综述

互操作是实现数字图书馆 (DLs)的集成或联邦所面临的中心问题。文章对DLs互操作的研究现状及关键技术进行了综述与讨论 ,主要内容包括 :⑴DLs互操作协议、DLs中间件、DLs中的信息发现、语义互操作和元数据互操作 ;⑵DLs互操作的实现方法及评价标准。最后 ,指出了DLs互操作今后的研究方向。     

Fatigue increases ankle sprain risk in badminton players: A biomechanical study

ABSTRACT

Ankle sprains are the most common injury in regular badminton players and usually occur at the end of a match or training. The purpose of the present study was to examine the influence of fatigue produced by badminton practice on the lower limb biomechanics of badminton players. It was hypothesized that fatigue induces ankle kinematic and lower leg muscle activity changes which may increase the risk of ankle sprain. Ankle kinematics, ankle kinetics and muscles activities of 17 regular badminton players were recorded during lateral jumps before and after an intense badminton practice session. Post-fatigue, ankle inversion at foot strike and peak ankle inversion increased (+2.6°, p = 0.003 and +2.5°, p = 0.005, respectively). EMG pre-activation within 100 ms before foot landing significantly decreased after fatigue for soleus (?23.4%, p = 0.031), gastrocnemius lateralis (?12.2%, p = 0.035), gastrocnemius medialis (?23.3%, p = 0.047) and peroneus brevis (?17.4%, p = 0.036). These results demonstrate impaired biomechanics of badminton players when fatigue increases, which may cause a greater risk of experiencing an ankle sprain injury.     

Modem拨号上网的连接过程分析和协议及报文详释

本文对使用Modem拨号上冈的连接过程及所用协议作了详细的阐述，并以通过联通171拨号上网访问网站Http://www.google.com/为例对报文进行了深入的分析．     

基于802.1 x认证的校园网的优化

在分析了传统的PPPOE和Web/Portal认证方式在局域网上存在的问题后 ,介绍了新的认证协议80 2 1x ,并给出利用 80 2 1x对校园网络进行优化的应用实例 .     

汽车多路复用传输系统及维修

介绍了汽车多路复用传输系统的优点，拓扑结构，传输介质，通信协议及常见典型结构，给出了采用不同网络协议的汽车多路复用传输系统常见的故障诊断方法。     

论文化语境对交际语言的制约和影响

语言是文化的载体,文化又是一种语境。人们的交际活动除了与一定的社会环境和自然环境相联系外,还与一定的民族、一定的时代的文化有密切的联系。文化语境不仅制约和影响着语言要素的选用和变化,而且还制约和影响着交际者对语言的理解。     

Triadic interaction in clinical task-based interviews with mathematics teachers

A clinical task-based interview can be seen as a situation where the interviewer–interviewee interaction on a task is regulated by a system of explicit and implicit norms, values, and rules. This paper describes how documenting and mapping triadic interaction among the interviewer, the interviewee, and the knowledge negotiated can be used to increase procedural replicability of the interview and accuracy of drawn conclusions about the interviewee’s thinking process. Excerpts from interviews with 25 inservice mathematics teachers working on a task to make up a problem whose solution requires division of two fractions are discussed. The excerpts illustrate the relationship between methodological decisions taken by the interviewer during the interview and the applicability of the interview output to the research questions. A divergent analysis of the interviews with these teachers, which spanned over two years and were conducted by four interviewers, is used to offer a framework for analyzing data collected in clinical task-based interviews.     

模糊限制语的合作原则分析

合作原则,作为一个重要的会话原则,在言语交际中被交际双方广泛地遵守着。但是,有时出于具体的交际需要和交际目的,也有很多违反合作原则的情况出现。本文运用合作原则对一个重要的语言现象——模糊限制语进行了语用分析。从合作原则的四个准则方面对模糊限制语进行了具体的分析,指出,为了达到交际目的,交际双方不得不使用一些模糊限制语,这看似违反了合作原则,其实是对合作原则的竭力遵守。     

Phonological Awareness Skills in Young Boys with Duchenne Muscular Dystrophy

Substantial research has detailed the reading deficits experienced by children with Duchenne muscular dystrophy (DMD). Although phonological awareness (PA) is vital in reading development, little is known about PA in the DMD population. This pilot study describes the PA abilities of a group of five young children with DMD, comparing the results with those of a group of children with spinal muscular atrophy and with those of a group of typically developing children. The Preschool and Primary Inventory of Phonological Awareness was used to assess the PA skills of the participants. Results indicated that the children with DMD performed significantly poorer than the typically developing group on tests of Syllable Segmentation, Rhyme Awareness, Alliteration Awareness and Phoneme Isolation and significantly poorer than the spinal muscular atrophy group on Rhyme Awareness. The findings of this pilot study indicate that children with DMD may have an increased risk of having PA difficulties, thus requiring early PA training.