桑蚕微粒子的胚种传染率

胚种传染是桑蚕微粒子病的重要传染途径，母蛾检验是控制该病害的重要措施，该技术在不断改进的同时，在实际生产中其成效也被得到充分的证实和肯定。微粒子病的胚种传染率是一个影响成品卵检验技术十分重要的因素，蚕品种、感染时间和母蛾感染程度等是影响胚种传染率的重要因素。微粒子病流行中胚种传染率变化等的研究将成为成品卵技术的成立提供重要的理论依据。     

Inoculation of infectious pancreatic necrosis virus serotype Sp did not cause pancreas disease in Atlantic salmon (Salmo salar L.).

Atlantic salmon were selected from a fish farm with no previous record of pancreas disease (PD) or infectious pancreatic necrosis virus (IPNV) infection. Groups of fish were inoculated with either IPNV (strain Sp) from cell culture, organ material from fish with PD or control material as phosphate-buffered saline (PBS). Virological, histological and immunohistochemical examinations were carried out throughout the experiment. None of the fish died or showed clinical symptoms of PD. Histological examination revealed no pathological changes, and immunohistochemical studies were negative. Virus was isolated only sporadically from the group inoculated with organ material, whereas it was isolated consistently from the group inoculated with virus propagated in cell culture, as well as from in-contact control fish after the first week. In a latent carrier test, changes were entirely lacking in the first mentioned group, and were only slight in the last mentioned group. The data suggest that PD is not a transmissible disease, and that IPNV isolated from a PD outbreak does not play any part in the etiology of this disease.     

淮河入海水道芦杨泵站工程伞齿轮传动贯流泵机组结构选型

介绍了大型伞齿轮传动贯流式机组所采用的水力模型、齿轮、轴承、密封、联轴器等结构的特点及其选用方法，所选用的机组具有结构简单，运行维护方便、安装工作量少及机组运行效率高等特点。可供泵站机组设计选型时参考。     

Evidence for transmission of bovine leukemia virus by rectal palpation in a commercial dairy herd

The risk of Bovine Leukemia Virus (BLV) transmission by rectal examination was determined over 22 months in a commercial dairy herd. All 167 BLV seronegative cattle, of breeding age or greater, were divided randomly into two groups and identified by neck-chain color. In the treatment group, routine rectal palpation occurred after a BLV infected animal and without a change of sleeve, while in the other group, palpation occurred in a similar manner with the exception that sleeves were changed between animals. When BLV seronegative cattle in either group were palpated after BLV infected cattle, the event and identification of the cattle involved were recorded. Serologic testing was performed eight times during the 22 month study to determine the number of animals that became infected following a palpation (an event). Thirty-one animals seroconverted during the study; 24 in the treatment (no sleeve change) group and seven in the sleeve change group. Sixteen of the animals in the treatment group that seroconverted had been palpated prior to their seroconversion. A hazard ratio (relative risk) for BLV seroconversion was determined between the two groups. Cows palpated with no sleeve change had a 2.8-fold increase in risk (confidence interval 1.1–6.8) of BLV infection. The increased risk of BLV infection associated with rectal palpation may have been affected by the presence of some highly infectious cows in the herd. This study confirms that rectal palpation without a change of sleeve may be a significant risk factor in some herds, and if efforts are made to decrease the spread of BLV in a herd, the potential for rectal sleeve transmission must be considered.     

水合物浆液流动特性研究

采用水合物循环管路装置,添加比例为水量2%(质量比)的防聚剂Span80,在压力为1.6MPa、温度为280.2K的条件下,测定了(柴油 甲烷 四氢呋喃 水)体系在不同水油体积比时生成水合物浆液的流体力学行为。将(水合物 液体)的非均相体系当作拟流体处理,建立了水合物浆液的流动模型,计算了各实验体系的表观粘度,分析了不同水油比时气体消耗量、流量、表观粘度随时间的变化趋势。     

表面等离子体激元基本特征研究

表面等离子体激元(Surface Plasmon Polariton,SPP)是束缚在金属表面的一种电磁波模式。研究了SPP的基本原理,推导出它的色散方程,计算了在可见光到近红外区域的与SPP有关的4个特征长度:SPP波长、SPP在界面上的传播距离以及SPP在介质和金属中的穿透深度。     

汽车自动变速器最佳换档车速的研究与分析

从典型电控自动变速器不能自动换档故障案例入手,分析车速和节气门开度两个参数对自动换档控制的影响,找出自动变速器液控系统和电控系统引起不能自动换档的故障原因,探求汽车行驶时如何根据路面、气候、车况等各种情况来确定最佳换档时刻所对应的车速,以及从原地起步连续换档的加速时间.通过车速、发动机转速、节气门开度以及感觉车身的振动试验,找出自动变速器的最佳换档规律,提供一种自动变速器故障诊断与排除的实用方法.     

Experimental infection of pigs with different doses of the African swine fever virus Armenia 07 strain by intramuscular injection and direct contact

We experimentally infected pigs with the African swine fever virus (ASFV) Armenia 07 strain (genotype II) to analyze the effect of different dose injections on clinical manifestations, virus-shedding patterns, histopathology, and transmission dynamics by direct contact. Each three pigs and four pigs were injected intramuscularly with 0.1 fifty percent hemadsorbing doses (HAD₅₀)/ml, 10¹ HAD₅₀/ml and 10⁶ HAD₅₀/ml of ASFV Armenia 07 strain, respectively. Each two of three pigs injected with 0.1 HAD₅₀/ml and 10¹ HAD₅₀/ml died by 10 days post inoculation. All pigs had a gross lesion of splenomegaly. Perigastric and renal lymph nodes were enlarged and resembled blood clots in nine of ten pigs. It was revealed that 0.1 HAD₅₀/ml of this ASFV was sufficient to infect healthy pigs by intramuscular injection and caused sub-acute lethal disease. For the transmission study, two 8-week-old pigs were injected intramuscularly with 10³ HAD₅₀/ml of the same virus. Each of the experimentally inoculated pigs was co-housed with two 8-week-old naive pigs. All contact pigs exhibited clinical manifestations at 6 or 7 days after the experimentally inoculated pigs developed pyrexia. These findings suggest that this strain may spread slowly within a herd. Histologically, lymph nodes resembled blood clots were formed by severe blood absorption and followed hemorrhage result of disruption of the lymphoid sinus filling with absorbed red blood cells. The severity of the gross and histological lesions depended on duration after infection, regardless of the difference of injection doses in this study.     

冀宁管道大汶河穿越带水开挖施工技术

通过对冀宁管道大汶河穿越施工方案的多次论证,确定大汶河采用带水开挖成沟、小平车轨道发送、控制负浮力、管道底拖法穿越的设计方案,该方案具有风险小、可实施性强等优点。介绍了大汶河带水开挖的设计思路和技术要点,阐述了带水开挖设计的一些经验和理念,为长输管道穿越特殊地质条件下的施工提供了技术上的支持和保障。