粉锈宁缓释剂防治玉米丝黑穗病

玉米丝黑穗病是贵州省玉米的主要病害之一,每年都造成严重损失。按常规使用0.08％粉锈宁农药直接拌干玉米种防治此病,防效差,易产生药害。将粉锈宁与聚乙烯醇等复配成缓释剂后拌萌动的玉米种,解决了药害问题,还提高了防效。     

Evaluation of a multiplex real-time RT-PCR for quantitative and differential detection of wild-type viruses and C-strain vaccine of Classical swine fever virus

Classical swine fever virus (CSFV) is the causative agent of classical swine fever (CSF), one of OIE listed diseases. Most of the currently available detection methods do not allow discrimination between wild-type CSF viruses and the vaccine strains. This study was designed to develop a multiplex real-time RT-PCR for the quantitative and differential detection of wild-type viruses and C-strain vaccine widely used in China. CSFV specific primers and two differently labeled TaqMan probes for the differentiation of wild-type viruses from C-strain vaccine were designed in the 5'-untranslated region of the viral genome of CSFV. The two TaqMan probes specifically hybridize wild-type viruses of different subgroups and C-strain vaccine, respectively, in the multiplex real-time RT-PCR, with no cross-reaction to a number of non-CSFV porcine viruses. The sensitivity of the assay for detecting wild-type and C-strain-type vaccine viruses was determined to be 41.8 and 81.5copies/microL viral RNA, respectively. Completely correct differentiation of wild-type viruses from C-strain vaccine was achieved when testing reference strains and characterized field isolates of CSFV in China. The multiplex real-time RT-PCR was able to detect the viral RNA in the whole blood samples of experimentally infected pigs as early as 2 days post-infection, 3 to 4 days prior to the onset of clinical signs in co-housed pigs. The agreements between the multiplex real-time RT-PCR and a multiplex RT-nested PCR for detection of wild-type and C-strain-type viruses were 96.9% and 100%, respectively, when detecting 106 different field samples. There is a positive correlation between the titers of C-strain vaccines titrated in rabbits and RNA copies quantitated by the multiplex real-time RT-PCR. The novel assay described here is rapid and sensitive, and is useful for differentiating field strains and C-strain of CSFV in China.     

Expression and significance of PTEN in canine mammary gland tumours

To explore the expression and clinical importance of the anti-oncogene phosphatase and tensin homologue deleted on chromosome 10 (PTEN) in canine mammary gland tumours, PTEN expression was compared in 50 cases of canine mammary tumour and four examples of normal mammary tissue using real-time quantitative PCR. PTEN expression was similar in benign mammary tumours and normal mammary tissues (P>0.05), but was lower in malignant tumours than in normal mammary tissues or benign mammary tumours (P<0.001). PTEN expression was also low in the lymph node metastases of malignant mammary tumours. The expression profile of PTEN in malignant mammary tumours compared to those without lymph node metastasis varied significantly. Low-level PETN expression might play an important role in carcinogenesis and the progression of canine mammary tumours, and PTEN protein detection might be useful in evaluating tumour development and prognosis.     

纸浆模塑餐具热压干燥过程的研究

该文对纸浆模塑餐具热压干燥工艺过程进行了分析,在此基础上建立了模具热传导方程,采用分离变量法推导出模具热传导方程的解析解,同时应用Matlab软件进行数值求解。根据热传导方程的解析解、数值解计算的模具表面温度值与与实测值较为吻合。对模具的传热分析为模具结构设计及加热管布置提供了理论依据。根据热传导方程并结合生产实际经验,推导出相应的湿坯热压时间,为热压过程的控制提供了基础。     

资源边际效益与种植业结构调整目标规划

根据北京市统计资料和已有研究数据,运用数学规划模型,对北京市种植业结构调整的目标与资源的边际效益间的关系作了分析,把模型的最优解建立在较为合理的资源边际效益和目标边际成本的基础上。结果表明：要提高水的效益和种植业产值,必须控制粮食作物和饲料作物的种植面积,在可灌溉耕地上的露地作物均应实行喷灌,应大力发展设施农业并实行微灌。     

基于电动比例调节阀的变量施药装置

利用电动比例调节阀作为流量调节执行器,以PLC为控制器,设计了基于流量直接控制方式的变量施药装置,并开发了相应的测控软件。通过试验得出了施药流量与电动比例调节阀开口度的关系,设计出适用于本装置的流量控制算法。试验显示,流量控制时最大平均误差为0.35L/min,最小平均误差为0.01L/min,表明装置能满足变量施药的要求。     

GM(1,1)模型在农村电力负荷预测中的应用

农村电力系统是一个含有许多不确定影响因素的灰色系统,而灰色模型法恰好是一种对含有不确定性因素的系统进行预测的方法,因此可将灰色模型法应用于农村电力系统负荷预测中。示例计算结果表明,用该方法预测电力系统负荷具有较高的预测精度。     

1LQ-40型开沟扶垄犁性能试验研究

秸秆整秆还田覆膜技术是实施土壤保护性耕作的重要措施之一,对解决北方旱区蓄水保墒,促进历史增产增收具有重要意义.1LQ-40型开沟扶垄犁是专为实施秸秆整秆还田覆膜技术所研制的机具.为此,通过对1LQ-40型开沟扶垄犁田间开沟作业的正交试验,研究该机具的作业性能和工作质量.结果表明:开沟深度、机器前进速度和开沟角度对开沟阻力有显著影响,为开沟机具的研究提供一定的依据.     

畜禽场球顶式沼气反应器设计系统的构建研究

在总结和构建了球顶式沼气反应器设计系统模型的基础上,采用面向对象的软件设计方法,将设计过程中各阶段的计算模型进行模块化分类,并植入软件,建立计算推理框架.软件将知识库与数据库关联,通过对条件参数的归纳整理和对数据库参数的调用,利用推理计算模型进行推理计算,实现了对畜禽场球顶式沼气反应器最终设计结果的推算和稳定性校核.畜禽场球顶式沼气反应器设计系统的研究和构建,提高了设计人员的工作效率,并使计算结果更加准确可靠.     

三种处理的玉米秸等量饲喂对绵羊增重的影响

选用当年的小尾寒羊公羔 30 只,分成三组,每组 10 只。在基础日粮相同的条件下,第 1 组加入玉米秸粉,第 2 组加入玉米秸穰饲料块,第 3 组加入全玉米秸饲料块,进行 100d 育肥试验。试验结果是:第 1 组平均日增重为 242 g ± 9.0 g;第 2 组平均日增重为 262 g ± 38 g;第 3 组平均日增重为246 g ± 29 g。经方差分析,三个组别差异不显著( > 0.05)。