基于CSMA/CD协议的以太网络性能仿真技术研究

根据以太网络的随机访问方式和到达帧的突发特性 ,证明了以太网络的帧到达过程服从泊松分布 ,提出了以太网络系统的排队模型 ,并对基于 CSMA/ CD协议的以太网络系统性能进行了仿真 ,研究表明这种仿真技术在评价网络性能时是一种非常有效和简单的方法     

一种基于数字证书的密钥托管方案

提出一种基于数字证书的密钥托管方案，用户和法律执行部门只需信任证书中心，无需大量的托管机构，简化了密钥托管管理，同时监听本身不会泄露被监听者的私钥，因此私钥不必因监听而更改。     

土木工程专业毕业设计问题解析

为帮助土木工程专业学生顺利完成毕业设计，结合历年毕业设计，对学生在方案阶段和计算阶段，遇到的问题，做一总结，并提出相关问题解决办法。帮助学生更好地理解和掌握知识点，尽快成长为一名合格的土木工程师。     

扩增香螺SSR指纹研究的试验条件的优化

利用SSR技术对香螺进行了PCR扩增,探索香螺基因组DNA的提取方法。从香螺23对近缘种引物中筛选出8对可以扩增的引物,对引物浓度、Taq酶浓度、循环次数、模板浓度等方面进行了研究,从而探索出一个适合香螺SSR分析的反应体系和反应条件并对微卫星引物通用性进行初步分析。     

基于USS协议下PLC在红枣加工系统中的应用

针对陕西北部红枣产量大、秋季雨水过多容易引发红枣肿胀破裂现象,加之当地并没有自动化加工设备以及流程不合理等问题,设计了一套红枣加工的自动化系统.在USS协议的支持下,S7-200 PLC在红枣加工系统中起到了很好的作用,实现了筛选、清洗、加工和包装的全自动化操作,解决了陕北自动化程度低的问题,在提高了农民经济效益的同时也提高了生产率,真正起到了工业发展的同时带动农业发展的作用.     

一种适用于PCR的环境友好型高质量植物DNA提取方法

改进DNA提取方法，利用含2%CTAB、1%SDS、2% PVP、100 mmol/L Tris-Cl (pH8.0)、20 mmol/L EDTA (pH8.0)和1.4 mol/L NaCl的DNA提取缓冲液，提取了不同种属12种植物的DNA，并对其进行了PCR检测．结果显示，所提取的DNA符合PCR试验要求，用真核生物ITS4/ITS5通用引物均能扩增出清晰的条带．该方法无需酚仿抽提，简单、高效、环保，特别适合大规模植物DNA的提取．     

Towards a best practice methodology for the detection of Phytophthora species in soils

The genus Phytophthora contains species that are major pathogens worldwide, affecting a multitude of plant species across agriculture, horticulture, forestry, and natural ecosystems. Here, we concentrate on those species that are dispersed through soil and water, attacking the roots of the plants, causing them to rot and die. The intention of this study was to compare the soil baiting protocol developed by the Centre for Phytophthora Science and Management (CPSM) with two other baiting methods used in Australia. The aim was to demonstrate the effectiveness of each protocol for soil baiting Phytophthora species in different substrates. Three experiments were conducted: the first to test the sensitivity of each method to detect Phytophthora cinnamomi, the second to test the effect of substrate type (sand or loam), and the third to test the detection of species (P. cinnamomi, P. multivora, or P. pseudocryptogea). The specificity of different plant species baits was compared within and between the methods. Substrate type influenced isolation in all methods; however, the CPSM method was superior regardless of substrate, albeit slower than one of the other methods for one substrate. Comparing bait species between the three methods, Quercus ilex was the most attractive bait for P. cinnamomi, particularly in the CPSM method. The choice of protocol affected the isolation associated with each bait type. Overall, the multiple bait system used by CPSM was shown to provide the most sensitive and reliable detection of Phytophthora species from soil samples.     

基于Internet远程RFID读写器通信设计与实现

本文提出了一种基于Internet网络,进行远程RFID读写器网络通信控制系统的设计与实现。详细阐述了嵌入式实时操作系统μC/OS-Ⅱ的移植过程及其提供的多任务环境,并阐述了在此环境下微控制器LPC2210与RFID读写器模块的通信硬件与软件的设计与实现。基于Internet的普及以及通信技术的迅速发展,论述了TCP/IP协议栈的移植原理,并完成微控制器与远程主机的以太网通信软件、硬件设计与实现。     

IPv6在网络考试系统中的应用

研究了IPv6互联网协议在网络考试系统中的应用,针对目前网络考试系统中存在的问题,有效地运用IPv6的优势加以解决,从而使网络考试系统更加完善、高效、安全。     

Changes in endocrine profiles during ovsynch and ovsynch plus norprolac treatment in Murrah buffalo heifers at hot summer season

The aim of this study was to compare the changes in hormonal profiles during ovsynch and ovsynch plus norprolac treatment in Murrah buffalo heifers following timed artificial insemination (TAI) at stressful summer months, through intensive endocrine analysis. The norprolac (an anti-prolactin drug) at the dose rate of 10.0 mg/animal /day effectively suppressed the level of prolactin upto 30 hours. The hormones quantified in blood plasma samples collected before, during and after ovsynch and ovsynch plus norprolac treatment were LH, prolactin, progesterone, estradiol–17β and total estrogens. The plasma prolactin and progesterone concentrations were negatively correlated (r = − 0.24) during summer estrous cycle, which indicated prolactin-induced suppression of progesterone secretion through poor luteal development. The ovsynch treatment reduced the incidence of anestrous from 45% before treatment to only 18% after treatment. The norprolac induced prolactin suppression improved the efficiency of ovsynch treatment upto 100% cyclicity after treatment in comparison to 36% acyclicity before treatment. In both the treatments 45% and 55% of animal became pregnant after TAI, respectively. The high prolactin secretion contributed to poor fertility by lowering gonadal hormones (estradiol-17β, total estrogens and progesterone) production in summer months. This finding of endocrine changes suggests that ovsynch protocol for estrus synchronization has potential application for improvement of fertility in repeat breeding buffaloes even during extreme summer months through suppression of prolactin secretion.