无线局域网(WLAN)中高速直接序列扩频(HR/DSSS)的实现

该文着重介绍了802.11b中提出的在WLAN中实现高速直接序列扩频(High Rate DirectSequence Spread Spectrum,HR/DSSS)的方法—补码键控(Complement Code Keying,CCK)调制,并以Intersil公司802.11解决方案中的基带信号处理芯片HFA3861b为例,说明了CCK调制在实际系统中的实现方法,最后对CCK调制的改进形式—格形编码(Trellis-Coded)CCK调制进行了概述。     

加入WTO后高职院的人力资源管理

中国加入世贸组织,职业教育作为可持续人力资源开发的重要组成部分,必须积极应对WTO对高职教育事业的挑战,本文论述了以人为本的管理思想,实施高职人力资源管理的策略。     

电工钢“以冷代热”的现状与思考

介绍了电工钢“以冷代热”的现状及存在的困难．阐述实现电工钢“以冷代热”的优势及有利条件。对加快电工钢以冷代热提出了一些具体的建议。     

纳米ZrO2薄膜的制备与表征

用水热盐溶液水解法可合成含有单斜相晶态纳米ZrO2颗粒的ZrO2溶胶体.用匀胶法制备的纳米ZrO2薄膜厚度约160 nm,折光率为1.56.纳米ZrO2薄膜表面质量良好,无表面裂隙,台阶仪研究表明薄膜表面粗糙度算术差Ra=2.7 nm,均方根差Rq=3.7 nm.以ZrO2为高折射率膜层,碱催化的溶胶凝胶SiO2为低折射率膜层,制备了SiO2/ZrO2多层高反射率薄膜,10周期的SiO2/ZrO2多层膜系,在1.06 μm波段处透过率为1%,薄膜表面抗激光损伤阈值约15 J/cm2(1.06 μm,2.5 ns高功率激光作用下).     

数控机床网络接口模块的设计与实现

为了对没有网络接口的老式数控机床实现网络化管理,采用STC15L2K40S2高速单片机和ENC28J60以太网控制器设计出了一款高性价比的数控机床网络接口模块。该模块利用数控机床的RS232串口扩展到以太网网络,在ENC28J60上实现了u IP协议栈,可以实现自动分配IP地址和屏蔽数控机床具体通讯细节,使用方便、操作简单,投入使用获得了较好的效果。     

4-己基间苯二酚最新研究进展

4-己基间苯二酚是一种新型的抗氧化剂,在医学上,它作为咳嗽的镇定剂有很长的应用历史;在食品上,最早应用于虾类保鲜,其后又应用在其它蔬菜水果的保鲜上。实验结果表明,4-己基间苯二酚有较好的保鲜效果,可防止虾类黑变,抑制蘑菇、鲜切梨、马铃薯的褐变,延长鲜切苹果的贮藏期,并能抑制微生物的生长,起到抗菌作用。     

变形、氘对HR1钢室温α′马氏体相变的影响

对预充氘和未充氘的HR1抗氢脆奥氏体钢试样以10-3s-1、10-4s-1和10-5s-1三种速率进行室温拉伸变形,采用XRD和VSM两种手段研究了室温下HR1钢的应变诱发α′马氏体转变行为,以及变形量、变形速率和预充氘对α′马氏体转变的影响。结果表明,HR1钢的未充氘试样在室温下以10-3s-1速率拉断后在断口附近发生了α′马氏体转变,变形量减小时,α′马氏体转变量减少;变形速率越慢,α′马氏体转变量越大。在室温准静态拉伸时,预充氘抑制了HR1钢中的应变诱发α′马氏体转变;变形速率下降,这种抑制作用增强。     

Evolution of M23C6 phase in HR3C steel aged at 650 °C

The evolution of the morphology, composition, and particle size of the M₂₃C₆ phase in HR3C steel aged at 650 °C was analysed, by means of metallographic microscopy, scanning electron microscopy, and transmission electron microscopy. The results showed that the Cr/Fe ratio in the M₂₃C₆ phase, in the form of irregular square and long strip, increased with the ageing time. Fe was gradually replaced by Cr in the M₂₃C₆ lattice. The M₂₃C₆ phase gradually evolved and then became stable after ageing for 2000 h.     

A comparative study on adopting human resource practices for safety management on construction projects in the United States and Singapore

Good project management outcomes include completing projects to an acceptable level of quality, within budget and on time. As construction accidents may cause project delays, safety management plays an important role in a project's timely completion. This study aims to undertake a comparative study of HR practices adopted for safety management on construction projects in the United States (US) and Singapore and to investigate the relationship between HR practices and construction safety management outcomes (severity and frequency of accidents). The research method included exploratory interviews and industry surveys of contractors in the US and Singapore by email and post. Data were collected using structured questionnaires. Compared to Singapore contractors, the results show that US contractors' project management practices place significantly more emphasis on highlighting organizational safety values to new workers and taking working experience into account during the selection process. On the other hand, Singapore contractors place more emphasis on providing appropriate rest areas for workers. Many HR practices are significantly correlated with safety management outcomes. These include: taking age into consideration during selection process and giving feedback to workers about their unsafe behaviour. It is recommended that project managers adopt relevant HR practices that lead to more effective safety management on construction projects.     

HR4 Gene Is Induced in the Arabidopsis-Trichoderma atroviride Beneficial Interaction

Plants are constantly exposed to microbes, for this reason they have evolved sophisticated strategies to perceive and identify biotic interactions. Thus, plants have large collections of so-called resistance (R) proteins that recognize specific microbe factors as signals of invasion. One of these proteins is codified by the Arabidopsis thaliana HR4 gene in the Col-0 ecotype that is homologous to RPW8 genes present in the Ms-0 ecotype. In this study, we investigated the expression patterns of the HR4 gene in Arabidopsis seedlings interacting with the beneficial fungus Trichoderma atroviride. We observed the induction of the HR4 gene mainly at 96 hpi when the fungus interaction was established. Furthermore, we found that the HR4 gene was differentially regulated in interactions with the beneficial bacterium Pseudomonas fluorescens and the pathogenic bacterium P. syringae. When hormone treatments were applied to A. thaliana (Col-0), each hormone treatment induced changes in HR4 gene expression. On the other hand, the expression of the RPW8.1 and RPW8.2 genes of Arabidopsis ecotype Ms-0 in interaction with T. atroviride was assessed. Interestingly, these genes are interaction-responsive; in particular, the RPW8.1 gene shows a very high level of expression in the later stages of interaction. These results indicate that HR4 and RPW8 genes could play a role in the establishment of Arabidopsis interactions with beneficial microbes.