987 resultados para 856
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对新型油水分离器关键装置柱型旋流器进行了性能实验研究,得到了压降,压降比与进口流量和溢流比之间的关系.结果表明,柱型旋流器内压降随着流量的增大而增大,呈抛物线型增长;压降比与溢流比之间呈线性关系.给出了计算旋流器压降的经验关系式.这些结果对柱型旋流器的设计运行和操作控制有着重要的指导作用,目前已用于南海平台油水分离器的现场实验
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用阈探测器活化法测量了每个核子动能(简称单核能)为50MeV18O离子轰击厚靶(Be、Cu、 Au)时出射中子的能量分布、注量率分布和中子角分布,得到了18O离子的中子产额、前向中子发射率和中子剂量当量率分布的数据。并与国外报道的单核能在20MeV 以下的低能重离子轰击厚靶研究中得到的中子剂量学参数进行了比较和分析。
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长白落叶松三种等位酶遗传型初步分析张军丽(中国科学院沈阳应用生态研究所,沈阳110015)本文采用淀粉凝胶电泳法,在酶水平上,利用“水平切片染色法”分析了长白落叶松(Larixolgensis)自然群体单株采集种子胚乳的三种等位酶的遗化变化情况。对苹...
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利用黑龙江省1949~1998年的调查数据和1949、1986年的两期1∶2500000森林资源分布图,从资源统计和景观格局两个角度对黑龙江省红松林的变化进行了研究。结果表明,从数量上看,黑龙江省红松林的面积和蓄积急剧减少,占全省森林资源的比例不断降低,林龄结构趋于不合理;从景观格局来看,1949年和1986年两期景观相比,红松林面积急剧减少,斑块数量增多,斑块密度加大,平均斑块面积减小,总边缘长度减小,边缘密度增大,呈严重的破碎化,大部分红松林景观转变为阔叶混交林和非林地。
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探讨了不同供水条件下土壤水分与作物产量的关系。[方法]以冬小麦品种长旱58为试材,设肥力和水分2因子高、中、低3水平9个处理组合,通过试验资料分析了不同养分和水分条件下作物的产量响应。利用2006年9月~2007年7月的气象资料研究了冬小麦不同生育期耗水量。[结果]各生育期耗水量占全生育期总耗水量的百分比以孕穗灌浆期最大,达45.6%,其次为拔节期,约21.5%,越冬期最小,约8.4%。底墒对旱作作物产量具有重要影响,施肥量过量会影响农田水分循环过程,使得高产农田的产量随降水量的变化而波动。[结论]提高作物土壤耗水量和土壤底墒利用率是黄土高原旱地农业实现高产稳产的关键。
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宁康霉素是由海洋细菌BAC-9912发酵获得的生物农药,对多种植物病原真菌有良好的抑制作用。本研究发现宁康霉素强烈抑制玉米纹枯病菌和苹果轮纹病菌的菌丝,可使玉米纹枯病菌菌丝枯萎和产生畸形。比较宁康霉素与农利灵和速克灵对玉米纹枯病菌的抑菌效果,结果显示宁康霉素的抑菌效果优于两种化学农药。
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Starting from nitrate aqueous solutions with citrate acid and polyethylene glycol (PEG) as additives, YVO4:Dy3+ phosphors were prepared by a two-step spray pyrolysis (SP). The obtained phosphors had spherical morphology. The luminescence properties of YVO4:Dy3+ phosphors were investigated by changing the concentration of Dy3+ and the annealing temperatures, respectively. The emission intensity of the phosphors increased with increasing the annealing temperature due to the increase of the crystallinity and particles size. The optimum concentration for the luminescence of Dy3+ was determined to be 2 mol% of Y3+ in YVO4 host.
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Separations of phenothiazines, promethazine(PZ), dioxypromethazine (OZ), chlorpromazine(CZ), trifluoperazine(TfZ) and thioridazine(TZ) by capillary electrophoresis in water and FA media were carried out and compared. Thus different selectivity and resolution were observed as media varying from water to FA. Migration order was PZ, OZ, CZ and TZ in water but (TZ+PZ), CZ and OZ in FA, when the same buffer, 25 mmol/L Tris and 25 mmol/L citric acid, was used. It also has been observed that pH has great effect on selectivity both in water and FA and a possible explanation was given. Separation efficiency was higher in FA media than in water because of the permission of high voltage applied. For all separations in FA 30 kV was applied, and when 25 mmol/L Tris was used as buffer, current was only 20 mu A and complete separation of TZ, CZ, PZ and OZ was achieved with effencicy higher than 3.5 x 10(5) theoretical plates for all analytes. The high performance of capillary electrophoresis in FA suggests that FA is an excellent media separation.
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以水和甲酰胺(FA)为介质,用毛细管电泳分离吩噻嗪类药物,比较了两者的选择性、柱效和分离度.与水相比,FA中选择性不同,有利于分离,被分析的物质均获得了较高的分离度;柱效显著提高,都在1×105以上,表明FA是一种良好的分离介质