灰口铸铁电弧热焊法补焊工艺的研究

文章分析了灰口铸铁的焊接性和常用的焊接方法,阐述了电弧热焊法对灰口铸铁进行补焊时的焊接工艺。     

低比转速离心泵塑料叶轮设计

以一台低比转速离心泵铸铁叶轮水力模型为原型,将其材质替换为塑料.考虑泵效率提升和注塑工艺可行性对叶轮几何参数进行修改:减小叶轮外径,增加叶轮出口宽度;考虑塑料结构工艺对叶轮结构进行调整:后盖板外侧设置加强筋,轮毂处加铜嵌件,盖板与叶片结合处添加定位孔销和焊接用导熔线。将塑料叶轮和铸铁叶轮安装在同一泵体进行对比测试。测试结果表明:塑料叶轮设计工况点泵的效率由56%提高到60%,增加了4%,既达到国家节能效率指标,又为用户节省了用电费用。     

用柞蚕卵自然诱集平腹小蜂的初步研究

用柞蚕卵进行田间挂卵自然诱集平腹小蜂的试验结果表明 :10月上旬诱集的数量最多 ,11月中旬后则诱集不到平腹小蜂 ;几种植物中 ,以芦苇上的卵卡诱集的蜂量最多 ,平腹小蜂的寄生率也最高 ;纸张作卵卡 ,以白色的效果最好 ;一般田间挂卵 10 d为宜 ;卵块的卵粒数以 14- 2 8粒较佳 ;平腹小蜂在白天活动 ,寻找寄主寄生 ,夜晚不活动 ,也不寄生 ;田间挂卵后 2 2 d,平腹小蜂即可羽化 ,羽化 4 d后达到高峰 ,同一批卵块平腹小蜂羽化时间可持续 1个月以上     

云杉落针病发病规律的研究

通过隔离接种和定点观察研究,在白龙江林区云杉散斑壳〔Ｌｏｐｈｏｄｅｒｍｉｕｍｐｉｃｅａｅ（Ｆｕｃｋｅｌ）Ｖ．Ｈｏｈｎ〕越冬场所有两种：一是在树上被侵针叶组织内以菌丝体越冬,二是在林地病落叶上以性子器越冬;子囊孢子为侵染源,只有初侵染;２ａ完成一个侵染循环;以气孔为主要侵入途径;主要靠气流、风、雨传播;病菌在４月下旬至７月上旬均可释放子囊孢子,释放的高峰期在５月中旬至６月下旬,侵染高峰期为５月下旬至６月下旬;降雨与子囊孢子关系密切;子囊孢子在空间分布是林缘多、林内少,随高度的增加而减少;７月底８月初,当年针叶出现初期症状,９月上旬以后,症状基本上无变化,病菌进入越冬,翌年３月底至５月中旬为病害症状明显期,病叶全部变为黄褐,逐渐干枯脱落。     

马蹄静脉构型的研究

用血管铸型法研究了马蹄静脉构型。结果是:马蹄静脉分为真皮外静脉系和真皮内静脉系。真皮外静脉系分为深浅两组。深组有轴平行静脉、终端静脉、蹄软骨内侧静脉网和指固有静脉后部吻合支;浅组有独立浅静脉、蹄冠静脉、蹄冠下静脉和蹄后静脉。真皮内静脉系:肉冠、肉壁近侧部有双层静脉网;肉壁远侧部、肉底、肉叉为单层静脉网。肉底静脉网呈多边形小环,靠近蹄匣增殖区静脉较粗。全部蹄静脉互相吻合成完整的立体网。大部静脉内缺乏瓣膜。蹄踵部静脉血有双重输出路线。蹄的震动和负重力是蹄静脉血回流的一种有效力。     

Impact of weather variables and season on sporulation of Phytophthora pluvialis and Phytophthora kernoviae

Phytophthora pluvialis and Phytophthora kernoviae are the causal agents of important needle diseases on Pinus radiata in New Zealand. Little is known about the epidemiology of the diseases, making the development of control strategies challenging. To investigate the seasonality and climatic drivers of sporulation, inoculum traps, consisting of pine fascicles floating on water in plastic containers, were exchanged fortnightly at five sites in P. radiata plantations between February 2012 and December 2014. Sections of needle baits were plated onto selective media and growth of Phytophthora pluvialis and P. kernoviae recorded. To explore the generalizability of these data, they were compared to detection data for both pathogens from the New Zealand Forest Health Database (NZFHDB). Further, equivalent analyses on infection of Rhododendron ponticum by P. kernoviae in Cornwall, UK allowed the comparison of the epidemiology of P. kernoviae across different host systems and environments. In New Zealand, inoculum of P. pluvialis and P. kernoviae was detected between January–December and March–November, respectively. Inoculum of both species peaked in abundance in late winter. The probability of detecting P. pluvialis and P. kernoviae was greater at lower temperatures, while the probability of detecting P. pluvialis also increased during periods of wet weather. Similar patterns were observed in NZFHDB data. However, the seasonal pattern of infection by P. kernoviae in the UK was the opposite of that seen for sporulation in New Zealand. Phytophthora kernoviae was likely limited by warmer and drier summers in New Zealand, but by colder winter weather in the UK. These results emphasize the importance of considering both environmental drivers and thresholds in improving our understanding of pathogen epidemiology.     

蚯蚓粪基质与肥料添加量对辣椒穴盘育苗效果的研究

将蚯蚓粪和蛭石按2∶1(v/v)的比例组成复合基质,然后添加不等量的CO(NH2)2和KNO3,用于辣椒穴盘育苗。结果表明:通过添加适量的肥料,可以明显提高复合基质的电导率(EC值),改善辣椒的出苗率和幼苗叶片叶绿素含量,显著促进幼苗植株的生长发育。根据壮苗指数,筛选出最佳肥料添加量是CO(NH2)20.2 kg/m3和KNO30.8 kg/m3。研究结果为利用蚯蚓粪替代草炭培育辣椒健壮穴盘苗提供了科学施肥依据。     

伏毛铁棒锤提取物对菜青虫的毒杀和拒食活性研究

[目的]研究伏毛铁棒锤(Aconitumflavum)对菜青虫(Pieris rapae)的毒杀和拒食活性。[方法]采用浸虫法测定伏毛铁棒锤乙醇粗提物和石油醚、乙醚、乙酸乙酯、正丁醇和水5种不同极性溶剂萃取物对菜青虫的触杀活性;采用叶蝶法测定石油醚、乙醚、正丁醇、乙酸乙酯、水的5种溶剂萃取物对菜青虫的拒食活性。[结果]伏毛铁棒锤粗提物对菜青虫具有较高的触杀活性,浓度为100.00 mg/ml时,48h的校正死亡率达97.24%,5种萃取物对菜青虫的触杀活性次序为水>正丁醇>乙酸乙酯>乙醚>石油醚,水萃取物48 h的校正死亡率达95.87%;5种溶剂萃取物拒食活性顺序为水>正丁醇>乙酸乙酯>乙醚>石油醚。[结论]伏毛铁棒锤提取物对菜青虫具有较强的触杀和拒食活性,且杀虫和拒食活性物质是一类极性较大的化合物。     

Susceptibility to IVM in a field strain of Haemonchus contortus subjected to four treatments in a closed sheep-goat flock in Kenya

Susceptibility to IVM (IVM) of “strain A” Haemonchus contortus which had been exposed to IVM four times over a 2-year period was compared to IVM susceptibility of “strain C” H. contortus which had no prior field exposure to IVM, by in vivo and in vitro methods. In vivo, the percentage reduction in faecal egg counts (FEC) and the total worm counts (TWC) were compared between control animals (lambs and kids) and animals treated with low dose IVM (20 μg/kg). In vitro susceptibility to IVM was evaluated by larval migration inhibition (LMI) after the two strains of H. contortus were exposed to different concentrations of IVM. The dose response, measured as the proportion of larvae inhibited from migrating, was used to estimate LD₅₀. Although differences in response to IVM in the in vivo determinations were not significant, “strain A” H. contortus had a significantly higher LD₅₀ than “strain C” in the LMI assay. Coincident with the conduct of the in vivo experiment, it was observed that “strain A” H. contortus established and survived better than “strain C” in the control lambs.     

农村散养畜禽寄生虫感染情况调查及防治报告

根据大竹县农村散养畜禽寄生虫病的感染情况及流行病学特点,提出了畜禽寄生虫病感染情况调查方案和驱虫试验。