新生仔猪产CNF大肠杆菌的实验感染

为了检测和比较大肠杆菌（Ｅ．ｃｏｌｉ）产生的细胞毒素坏死因子（ＣＮＦ），用１０＾１０Ｅ．ＣｏｌｉＯ３２菌株口服接种２窝仔猪。在２４小时内，接种Ｅ．ｃｏｌｉＯ８８的６头仔猪死亡２头，３头发生腹泻，其他仔猪于接种后１、５、６和８天屠宰，细菌培养表明感染Ｅ．ｃｏｌｉ者，早期整个大肠发生菌血症；呈现的早期肠炎病变，发展为小肠结肠炎；菌血症扩展到肺部；组织学病变为脑、心、肝和肾出现毒血症，呈充血、水肿和渗出     

母猪慢性子宫内膜炎的诊断与治疗

母猪慢性子宫内膜炎没有明显的临床症状,在工业化养猪业综合体,有15-20％母猪患病。在交配或人工授精前,临床观察发现518头母猪有慢性子宫内膜炎。母猪乏情期,没有子宫分泌物。此时,阴道检查也未发现有子宫疾病的任何症状。机体全身状态、体温、脉搏和呼吸都处在生理学范围之内。随着兴奋期开始,即看到生殖器排泄大量的卡他性或卡他脓性渗出物(特别是早晨在栏圈内躺卧地点)。大多数母猪性周期未破坏;但是,尽管     

Infectivity and pathogenicity of Cryptosporidium andersoni to a novel host, southern multimammate mouse (Mastomys coucha)

The infectivity and pathogenicity of Cryptosporidium andersoni (bovine isolate) for neonatal and adult southern multimammate mice (Mastomys coucha) was studied using transmission experiments. C. andersoni isolate used in this study was not infective for BALB/c mice, but experimental infection proved susceptibility of neonatal and adult M. coucha to the infection. The prepatent period was 20-24 days, the patent period varied between 46 and 59 days. No signs of clinical illness or macroscopic findings were detected in infected animals. Cryptosporidium developmental stages were detected only in the glandular part of the stomach of M. coucha in histological sections stained with Wolbach's modification of Giemsa and using immunofluorecence. Histopathological changes were characterized by dilatation and epithelial metaplasia of infected gastric glands without inflammatory response in the lamina propria. Neonatal M. coucha were more susceptible to C. andersoni infection than adults. M. coucha seems to be a useful laboratory model for study of C. andersoni infection.     

应用模糊数学方法评价全射流喷头

旋转式喷头的水力性能主要是由射程、流量、工作压力、喷灌强度、喷灌均匀度、水滴打击强度等六项指标综合决定,应用模糊综合评判的数学模型并结合试验数据评价国内外摇臂式喷头及全射流喷头的水力性能,结果表明隙控式全射流喷头比摇臂式喷头有更优越的水力性能。应用模糊数学方法时,权重分配会对评价结果产生影响,应根据实际需要选择最优的权重分配。     

沙沱水电站宽尾墩联合消能工的应

针对沙沱水电站泄洪量大﹑堰上水头高﹑单宽流量大的特点,分析了“宽尾墩+台阶坝面+戽式消力池”联合消能工的水力特性,通过模型试验对其消能效果进行了观测研究。试验结果表明：该消能方案在典型工况下消能充分,出池水流衔接平稳,下游河床无明显冲坑,满足通航要求,它既保持了大流量时宽尾墩的泄洪消能特点,又兼顾了台阶坝面小流量时的消能优势,并且采用台阶坝面使碾压混凝土一次成型,减少了工程量,缩短了工期,节省了工程投资。     

基于遗传算法的皮尔逊Ⅲ型曲线参

皮尔逊Ⅲ型频率曲线参数估计时,常用方法有矩法、权函数法和适线法等,这些方法各有缺陷。根据遗传算法全局寻优的原理与特点,采用遗传算法计算皮尔逊Ⅲ型频率曲线的三个参数,并和其他方法进行了对比验证。结果表明,遗传算法得到的频率曲线与实测资料误差小,拟合精度高,是一种较好的计算方法,值得推广应用。     

Detecting a fault line under a single phase to ground of distribution network based on analysis of multi frequency bands

Addressing the problem of choosing a fault line under single phase to ground of distribution network, we presented a new criterion based on analysis of the development of fault line selection and a method using wavelet packets. The feature frequency band, or the combined feature frequency bands of each line, in which the transient capacity current was concentrated was chosen for maximum energy. Based on the principle that the transient capacity current's energy of the fault line was larger than the that of normal lines, fault line selection can be carried out adaptively by contrasting the energy of the transient capacity currents of all lines in each chosen frequency band. The simulation results and spot testing data shows the proposed method can detect the fault line in distribution networks precisely and reliably.     

ADP在宽浅河道流量测验中使用小

在介绍宽带声学多普勒流速剖面仪ADCP测量河道原理的基础上,通过大量比测资料和理论分析，对宽带ADCP（简称ADCP下同）在北方宽浅河流流量测验应用中的单元尺寸和测量误差的关系进行探讨,提出了新的单元尺寸标准,拓展了ADCP的使用范围,提高了测验精度。别外,对缩小单元尺寸的理论依据进行了阐述.     

均质与非均质饱和土壤溶质穿透曲

在室内恒温条件下，分别对均质土柱和非均质土柱采用饱和一稳流一维垂直土柱易混置换法，就两种土柱对Ca2+，Cl-在土壤中运移的规律进行了初步研究。研究结果表明: Ca2+，Cl-在非均质土柱中的水动力弥散系数(Dsh)大于在均质土柱中的水动力弥散系数，而阻滞因子(R )则小于均质土柱。对于非均质土柱，其孔隙水平均流速也比较大，代换液浓度对穿透曲线（BTC）的影响不太显著；而均质土柱中代换液浓度对BTC影响较为显著，这可能是由于非均质土壤的孔隙度和土壤结构具有较为显著的空间非均一性所致。