POCSAG编码技术在农田灌溉中的应用

为了适应农田灌溉信息化和自动化的要求,本着经济性、实用性与可靠性的原则,基于POCSAG编码传输技术,设计了农田灌溉控制系统;论述了从发射到接收过程中POCSAG编码在容量、抗干扰和传输距离等方面的优势,以及由此构成的信号传输系统。该系统具有技术成熟、设备成本低、易实现等特点,解决了农田灌溉中点多、面广、地形复杂和距离远等问题,并自成一个独立控制系统,为建设农田灌溉控制信息化和提高用水管理水平提供了广阔应用空间。     

大射电望远镜平台静态结构参数误差分析与标定研究

为了提高大射电望远镜精调stewart平台的定位精度,首先利用激光跟踪仪（API）获得stewart平台的位置和姿态,其次基于运动学微分法建立了stewart平台的误差模型,最后针对大射电望远镜精调stewart平台进行了实验验证,实验结果表明stewart平台结构参数修正后,位置精度提高到0.09mm,姿态精度提高到0.014度.     

农业灌溉自动监测系统的设计

针对农业灌溉问题的特点,开发一种新型的基于GPRS技术的远程自动监测系统。通过GPRS无线通讯技术建立上位机与下位机的连接,对现场获得的测量数据进行实时监测,开发一种新型的农业自动灌溉监测系统。分别从系统方案、硬件和软件等几方面介绍了系统的实现。该系统已应用在农业灌溉监测系统中,实现对系统的自动监测,效果良好。     

基于RFID技术的生猪产业链信息采集研究

将无线射频识别(RFID)技术应用于畜产品信息可追溯系统的个体识别已经成为一种必然的趋势.以生猪产业链的信息采集规范研究为例,重点分析了生猪养殖、屠宰、加工、运输及销售环节的信息化流程,对生猪产业链中各信息采集点的信息采集流程和信息采集内容加以规范,为日后建立畜产品信息采集规范和畜产品信息可追溯体系提供了一定的借鉴.     

可追溯水产养殖质量安全管理系统设计

针对我国水产品行业存在的质量安全问题,以水产品为研究对象,建立了基于Web服务的数据传递技术的多层可追溯水产养殖管理系统,采用射频标签技术保证在整个流通过程中对鱼品身份的惟一标识。通过把标签上的信息输入到数据库中,初步建立了基于水产流通链的水产品信息可追溯系统,为生产者、检验者、监督者和消费者提供信息交互平台,从管理角度实现水产品流通过程中信息的存储、编辑以及查询等功能。     

过热蒸汽预处理对落叶松方材高频/真空干燥质量的影响

对落叶松髓心方材采用不同温度的过热蒸汽预处理,再利用前期试验得出的高频/真空干燥参数进行试验。结果表明,采用常压105℃过热蒸汽预处理31 h,高频/真空干燥后试材的表裂明显减少,且终含水率分布更加均匀;过热蒸汽预处理工艺使高频/真空干燥周期有所延长,但综合考虑干燥周期和干燥质量,认为此工艺具有可行性。     

Post‐release movements and habitat use of robust redhorse transplanted to the Ocmulgee River,Georgia

• 1. Robust redhorse Moxostoma robustum is an imperiled, potadromous fish in the south‐eastern USA. Initial recovery efforts have focused on supplementing existing populations and establishing refugial populations through extensive stocking programmes. However, assessment of the success of these programmes has not yet been conducted, and there are few reports evaluating the effectiveness of such programmes with other potadromous species.
• 2. Radio telemetry was employed to assess the effectiveness of a stocking programme aimed at addressing whether stocked individuals would remain in an area free of introduced predators and ascertaining the ability of stocked fish to integrate into a resident population.
• 3. Hatchery‐reared robust redhorse were captured from refugial populations established in other river systems and were transferred to the Ocmulgee River, Georgia where a population of hatchery‐reared individuals and an unknown number of wild fish reside.
• 4. These transferred robust redhorse exhibited an exploratory phase for the first 3 months before adopting behaviour patterns, including spawning migrations, that were consistent with those reported for wild fish in other systems. However, some individuals seemed unable to locate suitable spawning habitat.
• 5. Approximately half of the radio‐tagged fish remained within the area free of introduced predators.
• 6. At least some radio‐tagged robust redhorse fully integrated into the resident population as evidenced by their presence in spawning aggregations with resident individuals.
• 7. The effectiveness of a stocking programme is dependent upon the ability of stocked individuals to integrate into an existing population or replicate the behaviour and functionality of a resident population. Evaluations of stocking programmes should incorporate assessments of behaviour in addition to surveys to estimate abundance and survivorship and genetic assessments of augmentation of effective population sizes.

Published in 2008 by John Wiley & Sons, Ltd.     

基于认知无线电的频谱检测算法

认知无线电技术能够解决当前无线频谱资源匮乏而频谱利用率却非常低这一矛盾。无线频谱检测是认知无线电的关键技术。文章对匹配滤波检测、能量检测等单节点频谱检测方法进行了研究,并通过仿真对比分析了各检测算法的检测性能。在此基础上引入了合作检测方法,通过与单节点检测算法的对比仿真得出合作检测方式在性能上的优势。     

基于无线和短信环境安全型猪舍监控技术研究

通过无线和短信结合,实现了对环境安全型猪舍的监控。系统由无线智能传感器、无线或短信通信终端、监控中心和执行节点四部分组成,采用集散控制方法。监控中心是整个系统的核心,对数据进行集中管理、分析和处理,其他部分负责数据采集、传输和执行。     

Evaluation of Juvenile salmon passage and survival through a fish weir and other routes at Foster Dam,Oregon, USA

Downstream passage for juvenile Chinook salmon Oncorhynchus tshawytscha (Walbaum) and steelhead Oncorhynchus mykiss (Walbaum) through the fish weir at Foster Dam, Oregon, was evaluated to assess the weir's efficacy as a long-term passage solution. Radio telemetry was used to estimate survival, passage and effectiveness for the fish weir, spillway and turbines. Survival of Chinook salmon through the fish weir varied by season and reservoir elevation (66%–87%), and passage proportions were low (8%–20%). Fish weir effectiveness was low to moderate (0.39–2.09). Steelhead survival was lower (57%–77%) but passed the fish weir in higher proportions (77%), and weir effectiveness was consistently high (2.96–5.49). The results indicate the existing fish weir will not be a suitable long-term passage solution for all species. However, because of the high passage proportions and effectiveness observed for steelhead, further development of the surface-flow concept appears to be promising for safely passing downstream-migrating fishes.