油松容器苗枯梢症的预防     

马占宝  哈俊华 《青海农林科技》2008,(3)

在玛可河林业局育苗基地油松容器苗的培育过程中,发现有枯梢症发生,通过分析发生的主要原因,对油松枯梢症采取了预防措施,取得了明显效果.  相似文献   

Identification and characterisation of an H7N3 influenza A virus from an outbreak of virulent avian influenza in Victoria   总被引：1，自引：0，他引：1  

PW SELLECK  LJ GLEESON  FT HOOPER  HA WESTBURY  E. HANSSON 《Australian veterinary journal》1997,75(4):289-292

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Stabilization of ascorbic acid and its measurement by liquid chromatography in nonfat dry milk     

S A Margolis  I Black 《Journal of the Association of Official Analytical Chemists》1987,70(5):806-809

The determination of ascorbic acid by liquid chromatography (LC) was improved by performing the analysis in the presence of solvents that had been purged with argon to reduce the concentration of oxygen. This methodological modification eliminated the oxidation of ascorbic acid during the chromatographic procedure and reduced the minimum detection level to 1 microgram. Solutions of ascorbic acid have been successfully stabilized for 67 days by addition of dithiothreitol to a deaerated solution of water-acetonitrile (25 + 75 v/v), sealed under argon in amber vials and stored at -20 degrees C. In a second independent study, a procedure for the extraction of ascorbic acid from nonfat dry milk in a single step was developed. The ascorbic acid content of Nonfat Dry Milk (SRM 1549) was determined by LC, using the method of standard additions. The mean ascorbic acid content was 54 +/- 5 micrograms/g of sample. Analysis of variance of the analytical results indicates that there is a significant continual increase in the content of the ascorbic acid in each bottle from first to last sample.  相似文献   

披针叶黄华生物碱成分研究   总被引：4，自引：0，他引：4  

赵宝玉  张靖飞  哈斯巴图 《西北农林科技大学学报(自然科学版)》2002,30(3):9-12

采用 GC- MS联用分析技术从披针叶黄华总生物碱中分离鉴定出 12个喹喏里西啶生物碱 ,即无叶豆碱 ,N-甲基金雀花碱 ,金雀花碱 ,白羽扇豆碱 ,黄华碱 ,臭豆碱 ,N-甲醛基金雀花碱 ,Dodecahydro- 7,14 -methanodipyrido[1,2 - a:1′,2′- E][1.5 ]diazocine,Pyridine1- acetyl- 1,2 ,3,4 - tetrahydro- 5 - (2 - piperdinyl) ,7,14 -Methano- 2 H,6 H- dipyrido[1,2 - a:1′,2′- e][1,5 ]diaz,1,1- Dim ethyl- 3- (2 - nitrophenyl) ,7,14 - Methano- 4 H,6 H-dipyrido[1,2 - a:1′,2′- e][1,5 ]diaz。后 5种化合物为首次从该植物中鉴定  相似文献   

Establishment of cell type by compartmentalized activation of a transcription factor   总被引：48，自引：0，他引：48  

P Margolis  A Driks  R Losick 《Science (New York, N.Y.)》1991,254(5031):562-565

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日光温室CO2自动施肥系统的研制     

哈敏  李波  刘文合  张振厚 《沈阳农业大学学报》2001,32(6):473-475

研制了具有自动化特征的CO2施肥系统及其技术，并对该项技术的施肥效果进行了试验。结果表明：利用此装置，日光温室内的CO2浓度均匀程序较好，经济上可行，且气源来源广泛，长期施用对大气和土壤无污染，该项施肥技术加速了中国温室生产技术与世界发达国家接轨的进程。  相似文献   

农业分析实验课考试办法及标准     

席玉琴  王金娥  臧凤艳  哈玲津  张美婷 《天津农学院学报》2001,8(1):51-53

根据农业分析实验课的特点及内容提出了考试的办法，考试和考核的积分情况，制定了评分的标准以及有关扣分的说明。  相似文献   

Micromorphology and surface characteristics of lunar dust and breccia     

Cloud P  Margolis SV  Moorman M  Barker JM  Licari GR  Krinsley D  Barnes VE 《Science (New York, N.Y.)》1970,167(3918):776-778

Although nothing of direct biologic interest was observed in the sample studied, small shaped glass particles and glazed pits resemble objects which elsewhere have been described as fossils. These features, although nonbiological, do bear on processes of lunar weathering and outgassing. The glazed pits are impact features. Fusion of their surfaces released gases. Electron microscopy of the glasses, pits, and angular microfractured mineral grains indicates a prevalence of destructive weathering processes-thermal expansion and contraction, abrasion by by-passing particles, and, of course, impact. ous at room temperature.  相似文献   

Microtektites and mass extinctions: evidence for a late devonian asteroid impact     

Claeys P  Casier JG  Margolis SV 《Science (New York, N.Y.)》1992,257(5073):1102-1104

Glass spherules, similar to microtektites, have been found near the Frasnian-Famennian boundary (F/F) (Upper Devonian) at Senzeilles, Belgium, contemporaneous with one of the largest marine mass extinctions of the Phanerozoic. These spherules exhibit a wide range of compositions and display teardrop, dumbbell, and compound morphologies analogous to microtektites. In addition, they lack crystallites, have few or no vesicles, and have a low content of volatile material. These characteristics are supportive of an impact origin. The Siljan Ring (Sweden) and Charlevoix structure (Quebec,Canada) are candidate craters of this age. The presence of microtektites near the F/F boundary supports the hypothesis that an impact caused the Upper Devonian worldwide benthic mass extinctions.  相似文献   

Confident females?     

Margolis J 《Science (New York, N.Y.)》1996,272(5263):796c

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