以太网远程供水测控终端系统的设计

介绍了一种新型铁路供水远程测控系统的设计方案，详细地说明了远程测控终端系统的硬件电路和软件设计。系统由监控中心和分布在供水现场的单片机系统组成。两者之间通过RS485／以太网转换模块经以太网进行通信。其实际应用结果表明：该系统可靠性高，运行稳定，有很强的推广价值。     

Combination chemotherapy with L-asparaginase, lomustine, and prednisone for relapsed or refractory canine lymphoma

BACKGROUND: Canine lymphoma (LSA) is responsive to initial treatment, however, it then becomes resistant to drugs in the initial protocol. New rescue protocols are needed. HYPOTHESIS: A combination of L-asparaginase, lomustine, and prednisone will be well tolerated and efficacious as a rescue therapy for dogs with LSA. ANIMALS: Thirty-one client owned dogs with cytologically confirmed multicentric LSA who were refractory or whose disease had relapsed after a CHOP (cyclophosphamide/doxorubicin/vincristine/prednisone)-based chemotherapy protocol. METHODS: Prospective clinical trial. Lomustine (target dose, 70 mg/m2) was administered orally at 3-week intervals for a total of 5 doses or until disease progression. L-asparaginase (400 U/kg) was administered subcutaneously concurrently with the first 2 lomustine treatments. Prednisone was administered at a tapering dose for the duration of the protocol. RESULTS: Overall response rate for dogs treated with this protocol was 87% (27/31), with 52% (16/31) of dogs achieving a complete response. Median time to response was 21 days. Median time to progression was 63 days (111 days for dogs achieving a complete response and 42 days for dogs achieving a partial response). There were no significant differences in response rates and times to progression between dogs who had received L-asparaginase before beginning this rescue protocol and those who had not. Toxicoses were mild and self-limiting in 29 of 31 cases. CONCLUSIONS AND CLINICAL IMPORTANCE: This is a well-tolerated rescue therapy for relapsing LSA in dogs. Response rates and remission durations compare favorably to other rescue protocols. Therefore, this protocol is a viable rescue option.     

无线传感器网络技术研究

集传感器技术、嵌入式计算技术、分布式信息处理技术及无线通信技术于一体的无线传感器网络,因其广阔的应用前景而受到学术界和工业界的高度重视。为此,以综述的形式介绍了无线传感器网络的体系结构和面向于应用的网络协议,并对其研究方向和热点问题的进展进行了阐述。     

水产养殖参数无线测量网络的长生命周期研究

在水产养殖参数的无线测控网络中,测量节点能耗不均匀,个别节点由于能耗大过早失效,降低了网络的有效生命周期。该文对采用平面路由协议和低能量自适应分群分层路由协议(LEACH)的测控网络进行对比试验,发现采用LEACH协议网络的有效生命周期延长19%以上。在LEACH协议的水质参数测量网络中存在2个缺陷:一方面无线测控网络中每个簇的簇首功耗远远大于普通节点,LEACH协议通过等概率随机选择簇首部分改善了节点能耗的均衡性,但水产养殖参数监控中每个簇首功耗不同,为此在LEACH优化协议中依据节点剩余能量的多少选择簇首,使节点的剩余能量更趋均衡;另一方面水产养殖池中距离基站较远的节点容易提前失效,主要是因为监控面积大,簇首节点与基站采用单跳通信,远距离节点被选为簇首后向基站发送数据通信距离远,路径损耗采用多路径衰落信道模型,衰减指数为4。在优化协议中,对远距离簇首与基站通信采用双跳通信,使路径损耗采用自由空间信道模型,衰减指数为2。试验表明,无线传感网络有效生命周期延长了8%,各节点失效时间更趋接近。     

Linux下基于SSL和netfilter安全系统的设计

本文简要介绍了应用层级的安全协议SSL和Linux中netfilter框架结构及其过滤数据包的机制.最后通过SSL和netfilter相互结合,提出了一种对计算机网络系统本身及其传输的信息都具有安全防护的设计.     

基于无线射频识别的食品数字身份证设计及应用

食品质量安全可追溯体系对于保障食品安全具有重大意义.该文首先分析了食品数字身份证的具体需求,提出了通信安全性、系统的可用性、数据真实性、信息隐私性、信息权威性、可追溯性6个要求;然后对非对称加密算法NTRU(number theory research unit)和NTRU Sign数字签名算法进行了介绍,设计了安全认证协议,依据食品数字身份证的安全要求分析了安全性,建立了食品数字身份证.最后用食品数字身份证设计了电子酒类流通随附单,引入了生产商、销售商、消费者、认证中心4个角色,设立了认证注册、生产商信息写入、销售商信息写入和消费者验证4个过程,建立了系统应用原型,并分析了安全性,从根本上提高了电子酒类流通随附单的安全性和可信度.文章建立了食品数字身份证和酒类流通随附单,该工作对建立可靠、安全食品监管体系有十分重要的意义.     

船舶修造企业油漆堆放车间易燃易爆控制报警系统的研发

为解决沿海修造船厂的油漆堆放车间,在夏季高温下容易引起有毒与易燃气体的挥发泄漏而引起着火和工作人员中毒的威胁,设计了一种基于现场数据采集模块与PC设备以及移动无线设备的监控报警设备。介绍基于RS485总线MODBUS-RTU协议的数据采集单元的设计方法,单片机采集温度与有毒气体的实现方法,以及基于移动设备终端安卓系统下的应用软件的实现方法。     

Variations in the Diurnal Flux of Greenhouse Gases from Soil and Optimizing the Sampling Protocol for Closed Static Chambers

There is no standardized method for the sampling of greenhouse gas fluxes from soil. Two methods are primarily used: closed dynamic chamber (CDC) and closed static chamber (CSC) systems. The most complex and costly are the CDC systems, which can sample gases in situ. However, the low-cost CSC systems are being increasingly used in which the gas samples are collected manually and analyzed off-site at a later date. Given their growing popularity, it is important to optimize the sampling procedure of the CSC systems to ensure that the measurements are both repeatable and representative. Samples from a commercial potato crop were collected in the morning and afternoon at 0, 15, 30, 60, 90, and 120 min after the chambers were closed, and the concentrations of carbon dioxide (CO₂), methane (CH₄), and nitrous oxide (N₂O) were determined using gas chromatography. The concentrations of CO₂ and N₂O inside chambers increased linearly over time, whereas the concentration of CH₄ remained constant. The fluxes of CO₂ and N₂O from soil were greater in the afternoon than the morning, whereas the flux of CH₄ was greater in the morning. For longer-term single-point soil flux monitoring using CSCs with a volume of 6.3 L, it is recommended that samples are collected in the morning at 0, 30, and 60 min after chambers are closed. This approach will ensure that the concentration of the gases are representative and will allow for a high level of repeatability and certainty in the results.     

小麦基因组SRAP扩增体系的初步研究

对影响SRAP扩增结果的各种因素包括DNA、引物、dNTPMixture、TaqDNA聚合酶的浓度及变性、复性、延伸的时间及温度进行了摸索。获得了能够稳定扩增小麦基因组的体系:20μL体系中DNA25ng,dNTP188mmol/L,TaqDNA聚合酶0 75U,引物25ng。扩增程序为:94℃1min,37℃1min,72℃10sec,5个循环;94℃1min,50℃1min,72℃10sec,35个循环;72℃1min。     

不同部位烟叶外观特征与内在质量分析研究

要正确区分烟叶等级质量,必须首先分清烟叶的部位。本文通过生产试验,分析了不同部位烟叶的外观特征、内在质量、化学成分和物理特性等方面存在的差异。依据烟叶外观特征表现可正确地判定烟叶部位,从而更好地进行烟叶分级。