应用变频器使多台油泵软启动

如何实现用一台变频器使多台油泵软启动,其关键问题是逆变器与工频电源之间的双向切换。为了克服设备运行工况不稳定和电机二次启动冲击电流给电网带来的危害,必须实现平滑无冲击切换,这就要求切换的瞬间,逆变器输出电源的频率、相位、幅度与工频电网的频率、相位、幅度相一致。为实现平滑无冲击切换,研制出了单台切换器和适用于多台电机启动的配电线路及多台切换控制线路。切换器由相位鉴别器、幅度鉴别器、50周好检测电路、允许门电路、输出控制电路等五部分组成。经用户一年多实践证明,生产样机完全达到了设计要求,既保证了飞机加油又可进行油库装卸和输转作业,且从未出现故障。     

松嫩平原27县(市)粮食作物种植发展的灰色决策

本文运用灰色决策理论,在综合分析群众、专家和领导层意见的基础上,建议在“八五”期间,松嫩平原27县(市)四大作物(玉米、水稻、大豆、小麦)的发展策略应是适度发展。首先应侧重水稻高产田发展(400kg/亩以上),到1995年面积应稳定在248万亩左右,约占1989年该地区水稻播种面积的45.7％;其次是侧重发展玉米高产田(300kg/亩以上),到1995年稳定在759万亩左右,约占1989年播种面积的41.3％;再次是侧重大豆高产田(125kg/亩以上)面积,到1995年稳定在483万亩左右,约占1989年播种面积的35.8％。     

水涨龙眼结果母枝与果穗性状的相关性及其生物学指标

1986—1989年的研究表明,水涨龙眼结果母枝粗度与果穗生长关系最为密切,可作为衡量结果性能的主要生物学指标.提高结果母枝粗度可明显增加果穗重量,从而提高龙眼产量.当结果母枝粗度增加,果实数量相应增多时,其果穗会出现小果数增加的现象,应加强肥水供给.水涨龙眼优良结果母枝的生物学指标为:粗度0.60 cm 以上,长度8 cm 以上,复叶数5个以上.上述研究结果可为培养优良结果母枝提供重要依据.     

Satellite observations of smoke from oil fires in kuwait

Extensive dark smoke clouds associated with burning oil wells in Kuwait have been seen in data from weather satellites since early February 1991. The smoke is dispersed over a wide area. Variable and strong low level winds have held most of the smoke plume below 3 to 5 kilometers within a few hundred kilometers of the source. Thin veils of smoke have been detected in METEOSAT data as far away as 2000 kilometers east of Kuwait, over southwestern Pakistan at heights between 6 and 7 kilometers. The occasional presence of convective clouds over the fires indicates that some scavenging of the smoke is taking place.     

群选法在中国养羊业中的应用

群选法应具有八大原则:外貌一致;身体结构砖形;具有高度生产性能;正确的鉴定指标和方法;进行高度选种选配;淘汰要求严格;要有合适生态条件;选育方法不断改进. 组群数目和原则,羊群中符合育种指标的最好种羊,列入核心群;符合育种或接近育种指标羊群,列入一般群;不符合上述的羊只,列入淘汰群. 细毛羊鉴定指标如下:羊毛细度从60—70支;毛长7厘米长以上;毛密中等;弯曲形状要求大弯,少数可以中弯;油汗洁白或乳白,排出黄色及深黄;体重合乎育种指标,即公羊80公斤以上,母羊40公斤以上;产毛量为体重12％;净毛率一般为50％左右,不低于40％.     

中国落叶松-杨栅锈菌生理小种鉴定

对来自全国7个省市一定地域、不同年份、不同批次的15个落叶松-杨栅锈菌菌系 进行了 鉴别寄主反应型测定以及潜育期、产孢量观察,进一步明确了落叶松-杨栅锈菌在我国的 生理小种 分化。结果表明,15个菌系中的13个分别属于4个生理小种,Th 053 、Sb和Cj 052 归1号生理小种 CMLP 1 ,Ts 06 、Gl 051 、Hb 05ˉ1 和Sb 052 归2号生理小种CMLP 2 ,Qh 063 、Gl 052 、Hdao和Sb 051 归3号生理 小种CMLP 3 ,Bq和Qh 061 归5号生理小种CMLP 5 ,By 05ˉ3 和Zs暂单独划为1个致病类型。     

亚洲玉米螟大发生的因素及预测预报

亚洲玉米螟分布在东亚、大洋洲，公认为世界性的玉米主要害虫。笔者综合国内外资料同时结合多年研究工作，对玉米螟大发生的主要因素（如越冬种群质量特性和环境条件、越冬幼虫化蛹前的气候条件、玉米螟发生期田间气象条件及寄主植物）进行了综合分析，提出玉米螟大发生预测预报研究存在的问题及改进意见。     

Memory--a century of consolidation

The memory consolidation hypothesis proposed 100 years ago by Müller and Pilzecker continues to guide memory research. The hypothesis that new memories consolidate slowly over time has stimulated studies revealing the hormonal and neural influences regulating memory consolidation, as well as molecular and cellular mechanisms. This review examines the progress made over the century in understanding the time-dependent processes that create our lasting memories.     

影响灵武长枣生长的主要气象灾害初步研究

[目的]探讨影响灵武长枣生长的主要气象灾害。[方法]通过对历年灵武长枣产量与气象因子的统计分析,研究灵武长枣不同生长阶段气温、降水、相对湿度等因子对产量的影响。[结果]影响灵武长枣产量的主要气象灾害是盛花期出现连续9d以上≥30℃的高温天气、成熟期连续10d以上阴雨天气,盛花期连续7d以上阴雨天气以及越冬期出现4d以上≤-22℃的持续低温天气,同时极端最低气温达到-24℃。[结论]灵武长枣不同生长时段主要气象灾害不同。出现最多的主要气象灾害是盛花期连续9d以上≥30℃的高温天气。     

“书动人不动”馆际通借通还模式的探索与实践

＂书动人不动＂图书馆通借通还模式是在不增加任何附加条件和不改变现有环境的前提下,读者凭原借阅证在本馆、通过网络查询并办理借阅、归还其他图书馆图书手续的通借通还模式。＂书动人不动＂馆际通借通还是南京城东高校图书馆联合体创新的馆际通借通还模式,体现了＂读者为本＂的服务理念,已在汇文系统（libsys）得到了实现,并在联合体中正常运行。     

兰成渝成品油管道沿线地质灾害危险度区划

以兰成渝成品油管道沿线地质灾害为研究对象,通过对已有地质资料分析和野外调查,采用因子叠加法对地质灾害发育的基本条件、灾害诱发因素以及灾害现状进行了综合统计分析,并根据分析结果进行了管道区域地质灾害危险度区划和管道沿线地质灾害危险度分段区划。区划结果与管道沿线的实际情况相符。     

过量表达Trxs对H_2O_2胁迫下大麦幼苗叶片抗氧化酶活性的影响

[目的]分析过量表达Trxs对大麦幼苗叶片抗外源氧化剂胁迫的影响,为分析Trx参与植物抗氧化胁迫机制提供理论依据。[方法]以转Trxs基因大麦株系（LSY—11—1—1）及其非转基因对照株系为试材,研究了在1．5mmol／LH,0,胁迫条件下,Trxs过量表达对大麦幼苗叶片抗氧化酶活性的影响。[结果]在H：0：胁迫下,转基因大麦的聊,Tm与fV而值高于对照,而丙二醛与H2O2含量低于对照;转基因大麦的过氧化物歧化酶（SOD）、过氧化物酶（POD）与谷胱甘肽过氧化物酶（GSH—PX）活性普遍高于对照;转基因大麦与对照的SOD与GSH—PX活性变化趋势不一致;转基因大麦出现2次活性高峰,而对照仅1次。[结论]过量表达Trxs能够通过增强抗氧化酶活性有效地缓解H2O2胁迫对转基因大麦幼苗生长所造成的氧化损伤。     

Soap bubbles: two years old and sixty centimeters in diameter

Soap bubbles of long life (over 2 years) and large size (over 60 centimeters in diameter, 100 liters volume) have been produced from bubble solutions improved by the addition of water-soluble synthetic organic polymers such as polyvinyl alcohol or polyoxyethylene. The natural life can be defined as the time it takes for the bubble, if left undisturbed, to contract from the original size to a flat film.     

Potential magnitude of future vegetation change in eastern north america: comparisons with the past

Increases in atmospheric trace gas concentrations could warm the global average temperature 1.5 degrees to 4.5 degrees C by the end of the next century. Application of climate-pollen response surfaces to three climate model simulations of doubled preindustrial atmospheric CO(2) levels shows that the change in the equilibrium distribution of natural vegetation over eastern North America over the next 200 to 500 years could be larger than the overall change during the past 7,000 to 10,000 years and equivalent to the change that took place over the 1,000- to 3,000-year period of most rapid deglaciation. Some plant ranges and abundance maxima could shift as much as 500 to 1000 km during the next 200 to 500 years; such changes would have dramatic impacts on silvicultural and natural ecosystems. Although unprecedented vegetation change is likely if climate changes as predicted, forecasting the exact timing and patterns of change will be difficult.     

Vitamin D: A cholecalciferol metabolite highly active in promoting intestinal calcium transport

A major polar metabolite of cholecalciferol (vitamin D(3)) obtained from chick intestines is over four times as effective as cholecalciferol and over two times as effective as 25-hydroxycholecalciferol in stimulating intestinal calcium transport 24 hours after administration. Following a considerable lag, cholecalciferol and its 25-hydroxy derivative produce a maximum stimulation of the transport response at 24 to 48 hours. The polar intestinal metabolite greatly shortens this lag, stimulating maximum calcium transport by 9 hours. At 9 hours this metabolite is at least 13 times as active as the parent cholecalciferol and as such is a likely candidate for the biologically active form of cholecalciferol in the intestine.     

越夏期不同欧洲鹅耳枥品种耐热性评价

以欧洲鹅耳枥原种(Carpinus betulus)及其4个园艺品种贝克曼（Albert Beekman）、弗兰斯（Frans Fontaine）、卢卡斯（Lucas）、法斯塔（Fastigiata）为试验材料,观察其在南京地区自然越夏的田间性状表现,分析其越夏过程中生理生化指标的变化,并应用隶属函数法和系统聚类法对欧洲鹅耳枥各品种耐热性进行综合评价。综合评价后得出欧洲鹅耳枥各品种耐热性强弱依次为弗兰斯>贝克曼>法斯塔>原种>卢卡斯。热害指数和相对电导率能较好地反映欧洲鹅耳枥耐热性强弱,但部分生理生化指标在越夏期内变化规律性不强,应采用综合评价法进行耐热性比较。欧洲鹅耳枥各品种在南京地区可安全越夏,其耐热性综合评价结果与自然越夏田间性状表现一致。     

A theory of diversity equilibrium and morphological evolution

If the world can only support a finite amount of biomass, species might be added over time, with a decrease in population size of an average species. Population sizes of species will decrease to the extent that stochastic events eliminate species as fast as others appear, yielding an equilibrium. A resource diversity control of niche subdivision is therefore not needed to generate an equilibrium number of species. Morphological evolution may decelerate over time for similar reasons.     

西宁地区雷暴天气分析及预报方法研究

本文利用1981—2008年夏季（5—10月）西宁地区4个气象站的雷暴天气资料,分析了西宁地区雷暴天气的时空分布特征以及造成雷暴天气的环流形势与影响系统。为提高西宁地区雷电预报准确率,从天气学、统计学和能量天气学方面进行了研究,探索出了一套简单实用的预报指标和预报方法,建立了西宁地区雷暴天气动态分析和预报服务系统。     

有机硅助剂丝润防治B型烟粉虱成虫试验结果初报

在常规农药中添加有机硅助剂丝润可以提高防虫药剂效果,降低农药使用量。以用25%阿克泰防治B型烟粉虱为例,在杀虫剂中加入有机硅助剂丝润1000倍液可以降低农药使用量20%以上,提高防治效果10%以上。     

毛竹胸围与叶螨危害的关联分析

以2龄竹小爪螨（Oligonychus urama Ehara)量、3龄以上竹竹小爪螨量、3龄以上竹生理斑和真菌寄生斑、3龄以上竹南京裂爪螨（Schiotetranychus nanjingensis Ma et Yuan)丝巢数、3龄以上竹竹缺爪螨（Aponychus corpuzae Rimando）卵壳量为影响毛竹胸围的因子,应用灰色理论分析3种螨害及其它因素对毛竹胸围的影响。结果表明：对毛竹胸围的危害大小序列为：南京裂爪螨大于竹缺爪螨大于生理斑和真菌寄生大于竹小爪螨。