The Region 1 & 3 Broadcasting‐Satellite Service Plan after WRC‐03

The 1977 Broadcasting‐Satellite Service (BSS) Plan for Region 1 & 3 had been widely acknowledged to be out‐of‐date by the late 1980s. Development of digital modulation in the early 1990s provided an opportunity to update the technical provisions of the Plan to make it more economically viable. After a decade of work and three World Radiocommunication Conferences (WRCs), the revision of Region 1 & 3 BSS Plan was finally completed in 2003. The new Plan increased channel assignments from 5 to 10 analog‐equivalent channels for each country in Region 1, and from 4 to 12 channels for each country in Region 3. Yet, despite the increase in capacity, the new Plan is surprisingly similar to the original one in terms of the technical parameters. It is still based on national coverage, and the channel plan, orbital location, orbital spacing, and polarization are also the same. As a result, the new Plan is no more economically viable to implement than the old. To create economically viable BSS systems would most likely require modifications to the assignment in the Plan. Yet, modification procedures were made more difficult to apply after replanning. Less future implementation of BSS networks than would otherwise have occurred can be expected, and an inefficient usage of these frequency bands will likely result. On the other hand, less implemented systems will mean more capacity set aside for future use. This is important for countries that currently do not have satellite operations. In the end, BSS replanning reflects the eternal conflict between efficient usage and guaranteed future access. Copyright © 2005 John Wiley & Sons, Ltd.     

大棚温湿度无线实时监控系统的设计

提出了一种基于ZigBee技术的大棚温湿度无线实时监控系统的设计方法。该方法以SOC芯片CC2530和内核为Cortex-M3的STM32F107及温湿度传感器为硬件平台,可实现对大棚内气体和土壤温湿度的实时采集及空间定位功能,同时可将采集到的数据通过ZigBee网络传输到监控中心。     

STM32的双路信号源及其配置平台设计

针对目前测量分析、弱信号检测的需求,以STM32F107和AD9958为核心实现了一种高分辨率幅度、频率、相位的双路信号源。首先对直接数字合成(Direct Digital Synthesis,DDS)工作原理进行介绍,重点分析了杂散的主要来源,并设计LC椭圆低通滤波器对杂散进行抑制。设计输出电路使信号源满足低频需求,并可直接用于驱动负载。最后采用STM32F107和VC6.0搭建了配置平台,对信号源波形灵活控制。     

STM32F107的停车引导系统设计

本文设计的停车诱导系统以STM32F107微控制器为核心处理器,由RFID读卡器组成检测电路,用来检测停车场的车辆通过情况;有源RFID的无线模块发送信号,由检测模块将检测信号上传至上位机,由上位机控制停车场地面的指示灯(用来指示是否有车辆通过)的开启与关闭.采用Modbus通信协议进行控制和监控,实现了与外界环境相结合的人为可控智能闭环系统.     

ZL107合金热力学显微组织分析

应用热力学计算对平衡条件下ZL107合金组织进行了定量分析,研究了化学成分和温度对ZL107合金组织的影响规律,并对该合金的显微组织进行了观察。结果表明,ZL107合金中Al2Cu强化析出相开始析出温度及数量主要取决于Cu含量,增加Cu含量可以提高Al2Cu相数量及析出温度。在210℃以上时效会导致Al2Cu相数量下降。热力学计算确定的最佳固溶温度和时效温度分别在510～520℃和150～200℃之间,热力学计算结果和试验结果相符。     

快速硫化缩合型RTV-2硅橡胶的研制

以107硅橡胶为主要原料,正硅酸酯类为交联剂,有机锡类为催化剂,配制了缩合型双组分室温硫化(RTV-2)硅橡胶.通过共聚配方的设计,使硅橡胶的硫化速度得到显著提高.较佳的配方是:以100份107硅橡胶计,正硅酸乙酯用量为10%,二醋酸二丁基锡用量8%,KH-550的用量0.33%.得到的硅橡胶满足了液态有机污染物泄露事件快速堵漏及公安部门迅速、精确提取立体犯罪痕迹等场合对硅橡胶硫化速度的要求.     

缝洞碳酸盐岩凝析气藏注水替凝析油实验

缝洞型碳酸盐岩油气藏是一种复杂、特殊类型的油气藏,其储层以缝洞和裂缝-孔洞为主,具有双孔隙网络特征及较强的非均质性,渗流规律复杂,实现该类油气藏的高效开发是诸多石油工作者关心并一直致力于研究的问题.借鉴在缝洞型碳酸盐油藏中应用效果较好的“注水替油”方法,建立了缝洞型碳酸盐岩凝析气藏“多级压力注水替凝析油”方法,并以高含凝析油的TZ86井为例,采用露头碳酸盐岩经过人工造缝造洞技术制成全直径缝洞型岩心,在原始地层条件(140.6℃,58 MPa)下进行了多级注水替凝析油物理模拟实验,结果表明采用多级注水替凝析油方式开发缝洞型碳酸盐岩凝析气藏可取得较好效果.     

基于Cortex-M3处理器和CC2430的无线网关设计

本文以cortex M3处理器STM32F 107和CC2430为核心,采用UIP协议栈和mCOS Ⅱ实时操作系统,设计了2.4Gllz带宽的无线网关,该网关可以通过Modbus TCP协议与组态王等组态软件相连,与配套的测量节点组成监测网络,通过msstatePAN 协议通信,用于精准农业、压力监测等领域.     

J107型甲烷化催化剂开车小结

针对甲烷化催化剂中毒失活的原因，介绍改用是Ｊ１０７型甲烷化催化剂升温还原和开车情况。     

合成107胶时产生凝胶的原因及解决办法

从反应温度和时间、理论取代度、理论固含量这三个方面初步探讨了合成107胶时产生凝胶的原因以及如何解决产生凝胶的办法。并且我们合成了理论取代度高达53％，而又在合成过程中不产生凝胶的107胶。