泡沫比例混合器在液下喷射灭火系统中的应用     

郑华林  冉隆雪 《油气储运》2001,20(9):53-55

提出了环泵泡沫比例混合器和泡沫压力比例混合器在相应灭火系统中的应用、安装和操作中应注意的问题，对两种泡沫比例混合器组成的系统进行了对比，认为环泵比例混合泡沫灭火系统采用正压进水，可以克服负压进水方式存在的缺陷，比较适合油库火灾的扑救；压力比例混合泡沫灭火系统灵活性、匹配性较差，适用于泡沫混合液流量相对不变的火灾扑救。  相似文献   

Viral and bacterial agents associated with experimental transmission of infectious proventriculitis of broiler chickens.   总被引：1，自引：0，他引：1  

G R Huff  Q Zheng  L A Newberry  W E Huff  J M Balog  N C Rath  K S Kim  E M Martin  S C Goeke  J K Skeeles 《Avian diseases》2001,45(4):828-843

Proventriculitis of broilers can be reproduced by oral inoculation of day-old chicks with a proventricular homogenate from affected 3-wk-old broilers. The objective of the following studies was to isolate from this homogenate viral and bacterial isolates that could produce proventriculitis. A monoclonal antibody to infectious bursal disease virus (IBDV) was used to precipitate virus from the homogenate. A primary chicken digestive tract cell culture system was also used to isolate virus from a 0.2-microm filtrate of the homogenate, and a bacterium was also isolated from the homogenate. In trial 1, day-old birds were orally inoculated with either proventriculus homogenate or monoclonal antibody immunoprecipitated IBDV (MAB-IBDV). At 4, 7, 14, and 21 days postinfection (PI), 12 birds from each treatment group were subjected to necropsy. In trial 2, day-old birds were orally inoculated with either infectious proventriculus homogenate, suspect virus isolated in cell culture and propagated in embryo livers and spleens, or a bacterial isolate. Twelve birds from each treatment were subjected to necropsy at days 7, 14, 21, and 28 PI. In trial 3, treatments were maintained in negative pressure isolation chambers, and an additional treatment included virus plus bacterial isolate. Twenty-four birds from each treatment were subjected to necropsy at day 21 PI. In trial 1, infectious homogenate decreased body weight and relative gizzard weights at 4, 7, 14, and 21 days PI. Proventriculus relative weight was increased at days 7, 14, and 21 PI, and proventriculus lesion scores were increased at days 14 and 21 PI. Bursa/spleen weight ratios were decreased at day 14, and feed conversion was increased at days 4 and 21. The MAB-IBDV treatment decreased proventriculus and gizzard relative weights at day 4 PI, increased proventriculus lesion scores and bursa/spleen weight ratios at day 14, and decreased heterophil/lymphocyte ratios at day 21. In trial 2, all infected birds had significantly higher mean relative proventriculus weights at 21 days PI and had higher 4-wk mean proventriculus scores as compared with both control groups. In trial 3, birds treated with homogenate and birds treated with both suspect virus and the bacterial isolate had significantly higher proventriculus lesion scores; higher relative weights of proventriculus, gizzard, liver, and heart; lower body weights; and lower relative bursa weights compared with the saline control group. These studies suggest that infectious proventriculitis has a complex etiology involving both viral and bacterial infection.  相似文献   

鸡的微卫星DNA标记与胴体性状的相关分析   总被引：4，自引：1，他引：3  

陈晖  郑丽祯  陈岩锋  郑嫩珠  缪中纬  陈宽维  汤青萍 《中国家禽》2004,8(Z1):137-140

测定了青脚麻鸡与隐性白鸡杂交后自交的F2代个体的全净堂重、全净堂率、脂肪宽带、腹脂重和腹脂率6个胴体性状,检测10个微卫星DNA标记,对标记基因型胴体性状值进行方差分析和多重比较,结果表明:MCW328对于10周龄体重和全净膛重两性状各基因型均有显著的差异(P<0.05);ADL292对于腹脂重性状各基因型有极显著的差异(P<0.01),对于腹脂率有显著的差异(P<0.05)。MCW328标记基因与控制10周龄体重和全净膛重QTL连锁,ADL292标记基因与控制腹脂重和腹脂率QTL连锁。  相似文献   

杨梅袋苗大棚嫁接及管理技术     

郑友明 《福建果树》2004,(4):48-48

杨梅是我国的特产水果，福建的“浮宫杨梅”以成熟期国内最早、色泽紫红、酸甜适口而受到广大消费者的青睐，果品销往国内各大城市和东南亚地区，2004年首次出口到欧盟，市场前景广阔。杨梅传统的繁殖采用大苗嫁接法，即先在定植穴种实生苗，2～3年或更长时间后再进行嫁接。  相似文献   

中国上市公司多元化经营绩效的实证分析     

秦拯陈收  邹建军 《湖南农业大学学报(自然科学版)》2004,(2)

通过随机抽样,计算我国57家上市公司1998年-2002年的平均盈利指标和风险指标,根据各公司多元化熵值的大小对样本总体进行分组,分析多元化程度对企业绩效的影响.研究发现1.多元化程度越高,公司的平均净资产收益率越高;2.多元化经营降低了公司收益率的波动水平;3.资产规模越小的公司越倾向于选择多元化经营.  相似文献   

槟榔红色素的抗氧化活性   总被引：2，自引：1，他引：1  

郑亚军  苏冰霞  陈卫军  李艳  赵松林 《热带作物学报》2009,30(6):881-884

测定槟榔红色素(areca red pigment,AP)对 DPPH·和·OH的清除能力、对脂质体过氧化的抑制能力、对Fe2+的络合能力,并测定其还原能力.结果表明:槟榔色素对DPPH·、·OH的清除能力较强:对脂质体过氧化的抑制能力很强,抑制率高达79.84%;与VE、没食子酸(gallic acid,GA)、BHT相比,槟榔色素的还原力、对Fe2+的络合能力较弱.说明槟榔红色素是较好的抗氧化剂.  相似文献   

电导法测定林木种子活力的研究   总被引：4，自引：0，他引：4  

郑郁善 《福建林学院学报》1989,9(2):199-202

本文研究了林木种子电导法测定条件和测定电导率或相对电导率,通过回归分析建立电导率或相对电导率与种子活力指数的相关方程,找出了电导法测定林木种子活力的方法。  相似文献   

天山北坡中山带野生牧草种质资源评价     

郑子英 《草业科学》1995,12(4):2-4

通过对新疆３８野生种牧草种植试验，证明许多野生牧草不但在产量、质量上高于栽培牧草，在抗逆性能方面也为许多载培牧草所莫及，对建设新疆中山带的优质人工草地具有重要意义。  相似文献   

三峡库区柑桔林水土保持效益分析   总被引：1，自引：0，他引：1  

郑巍伟  张春林 《亚热带水土保持》2006,18(1):15-18

对三峡库区2种不同建园方式的柑桔林,从建园开始连续9年定位观测柑桔林水土流失情况,结果表明,梯田柑桔林径流系数在0.047~0.153之间,径流含沙量在425~2170g/m3之间,侵蚀模数在9.37~116.67g/m2之间。25°坡地柑桔林径流系数在0.079~0.378之间,径流含沙量在500~5 050 g/m3之间,侵蚀模数在48.29~1 962.04g/m2之间。在建园初期4年内,25°坡地柑桔林径流系数、径流含沙量和侵蚀模数急剧下降,径流系数由0.378下降到0.103,径流含沙量由5050 g/m3下降到350g/m3,侵蚀模数由1 962.04g/m2下降到131.42 g/m2。4年后,覆盖度的增加有效的抵消了坡度对水土流失的影响,柑桔林覆盖度达到0.82,径流系数,径流含沙量和侵蚀模数分别为0.103~0.253,350~3404 g/m3、14.71~148.4g/m2,表现出较好的水土保持效益。  相似文献   

3种农药的微核效应研究   总被引：6，自引：0，他引：6  

唐正义  胡蓉  岳兴建 《西南大学学报(自然科学版)》2006,28(1):70-73

运用蚕豆根尖微核技术研究3种农药(甲胺磷、甲基硫菌灵和盐酸吗啉胍)在不同浓度下的诱变效应。结果表明,3种农药诱发蚕豆根尖细胞微核率与对照组相比均有不同程度的上升(P<0.05或P<0.01),农药浓度与微核率呈剂量-效应关系,盐酸吗啉胍的诱变效应大于其他2种农药。  相似文献