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Search Results: 1 - 10 of 103455 matches for " 闫宇平 "
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环北极地区冰芯记录揭示的北半球海盐气溶胶大气传输方式
,康世昌,孙俊英,Paul,A.,Mayewski,秦大河
中国科学 地球科学 中国科学 地球科学 , 2004,
Abstract: ?根据冰芯化学记录重建大气环流历史,需要认识雪冰化学成分的控制因子,诸如其来源、大气传输途径及强度.为了解这些过程,研究了北半球两支冰芯化学记录(加拿大育空地区洛根山冰芯和格陵兰南部20D冰芯)与北半球海平面气压(SLP)的相互关系.结果表明,洛根山冰芯中ssNa+浓度与秋季阿留申低压和夏季北太平洋副热带高压关系密切.秋季阿留申低压的加深和夏季北太平洋副热带高压增强都有利于海盐气溶胶从北太平洋向育空地区传输.20D冰芯中ssNa+浓度与冬季冰岛低压密切相关.加深的冰岛低压加强了北大西洋冬季风暴和气旋的生成,为格陵兰冰盖输送了更多的海盐气溶胶.因此,洛根山冰芯ssNa+记录可以作为重建秋季阿留申低压和夏季北太平洋副热带高压的指标,而20D冰芯ssNa+记录可作为重建冬季冰岛低压的指标.
近45年雅鲁藏布江流域极端气候事件趋势分析
游庆龙,康世昌,,徐彦伟,张拥军,黄杰
地理学报 , 2009, DOI: 10.11821/xb200905008
Abstract: 利用雅鲁藏布江流域10个气象台站1961-2005年逐日最高气温、最低气温和日降水量资料,分析了该流域气温和降水等气候极端事件的变化趋势。研究表明近45年以来,雅鲁藏布江流域夜间和白天极端低温日数分别以1.94和0.97天/10年的趋势在显著减少,夜间极端低温日数减少在冬季最明显,白天极端低温日数在秋季减少最明显;夜间极端高温日数和白天极端高温日数分别以3.03和1.26天/10年的速度显著增加,夜间极端高温日数增加在夏季最明显,白天极端高温日数增加在冬季最明显;日较差以0.11oC/10a的速度在显著减少,主要发生在冬季;最大的1天降水总量和逐年连续无降水天数有减少趋势,最大的5天降水总量、中雨天数、逐年平均降水强度和逐年连续降水天数有增加趋势,90年代以来增加趋势明显,与该地区经向风与水汽通量增加有关。
蚕丝织物的原位纳米银抗菌整理
高晓红,贾雪,陈从阳,张凌,
纺织学报 , 2013,
Abstract: 探讨了银氨溶液浓度、溶液温度、处理时间等对银负载量的影响,得出银氨溶液处理真丝织物负载银的合适工艺。利用该法处理的真丝织物对大肠杆菌和金黄色葡萄球菌都具有优良的抗菌性,并具有良好的耐洗性
微丝骨架与信号转导研究进展
,芝芬,严玉,魏建昆
华北农学报 , 2000, DOI: 10.3321/j.issn:1000-7091.2000.01.008
Abstract: 微丝骨架作为细胞骨架的一种,它在细胞的许多功能活动中起重要作用。近年来,研究证明微丝骨架受信号转导的调节。动物细胞中存在着细胞外基质(ECM)质膜(PM)细胞骨架(CTK)连续体,胞内、外信号可以通过此连续体进行双向传递。研究还证明,植物细胞中存在细胞壁(CW)质膜(PM)细胞骨架(CTK)连续体,并认为它类似于动物细胞中的ECMPMCTK连续体,有着相同的功能。本文还对调节微丝骨架的主要信号传递途径进行了综述。
日益孤独的中国老年人:一项横断历史研究
志民,李丹,,余林,杨逊,朱水容,
心理科学进展 , 2014,
Abstract: ?随着社会的巨大变迁,我国老年人孤独感水平可能逐年增高。通过采用横断历史研究的方法,对使用ucla孤独量表(第三版)调查老年人孤独感的25篇文献进行元分析,调查年代跨度为1995年至2011年,共涉及13280名老年人。研究结果表明:(1)我国老年人孤独感水平随年代的变迁呈上升趋势;(2)不同婚姻状况、不同性别老年人的孤独感水平随年代均呈上升趋势;(3)老年人孤独感水平存在婚姻状况差异,但不存在性别差异。
外来植物火炬树水浸液对土壤微生态系统的化感作用
侯玉,柳林?,王信?,,门航?,李伟杰?,徐维明?
生态学报 , 2013,
Abstract: 引种自北美的外来植物火炬树(rhustyphinal.)是中国北方主要造林树种之一。然而,近年来分布区的不断扩大暗示着该树种的潜在入侵性。以火炬树为对象,研究火炬树不同浓度(0、0.005、0.025、0.1g/ml)的鲜枝叶水浸液对土壤微生物群落结构、酶活性、土壤养分含量及土壤矿化的影响。研究结果表明:随着水浸液浓度的提高,火炬树增加了细菌和真菌的数量;火炬树对所测土壤酶活性产生了不同程度的影响,脲酶和磷酸酶均有随着水浸液浓度的提高而增大的趋势,而蔗糖酶活性受影响不明显;随水浸液浓度升高,火炬树显著提高了土壤全碳、全钾、速效氮、有效磷、速效钾的含量,对土壤含水量、ph值、全氮与全磷没有显著影响;同时,火炬树通过促进微生物的矿化速率,提高了土壤无机氮的供给。以上结果表明,火炬树可以改变土壤的微生物组成和土壤酶活性并影响土壤相关营养元素循环,从而为自身的入侵创造有利条件。本研究揭示外来植物火炬树水浸液对土壤微生态系统的影响,从化感间接作用角度为火炬树的潜在入侵性提供进一步的数据支持。
Climate change over the Yarlung Zangbo River Basin during 1961-2005
雅鲁藏布江流域1961-2005年气候变化趋势

YOU Qinglong,KANG Shichang,WU Yanhong,YAN Yuping,
游庆龙
,康世昌,吴艳红,

地理学报(英文版) , 2007,
Abstract: The Yarlung Zangbo River (YR) is the highest great river in the world, and its basin is one of the centers of human economic activity in Tibet. Using 10 meteorological stations over the YR basin in 1961-2005, the spatial and temporal characteristics of temperature and precipitation as well as potential evapotranspiration are analyzed. The results are as follows. (1) The annual and four seasonal mean air temperature shows statistically significant increasing trend, the tendency is more significant in winter and fall. The warming in Lhasa river basin is most significant. (2) The precipitation is decreasing from the 1960s to the 1980s and increasing since the 1980s. From 1961 to 2005, the annual and four seasonal mean precipitation is increasing but not statistically significant, especially in fall and spring. The increasing precipitation rates are more pronounced in Niyangqu and Palong Zangbo river basins, the closer to the upper YR is, the less precipitation increasing rate would be. (3) The annual and four seasonal mean potential evapotranspiration has decreased, especially after the 1980s, and most of it happens in winter and spring. The decreasing trend is most significant in the middle YR and Nianchu river basin. (4) Compared with the Mt. Qomolangma region, Tibetan Plateau, China and global average, the magnitudes of warming trend over the YR basin since the 1970s exceed those areas in the same period, and compared with the Tibetan Plateau, the magnitudes of precipitation increasing and potential evapotranspiration decreasing are larger, suggesting that the YR basin is one of the most sensitive areas to global warming.
东北三省水稻穗上不同部位碾磨及外观品质的比较研究
侯昱铭,李红,陈英华,权成哲,,武洪涛,陈温福,徐正进
华北农学报 , 2009, DOI: 10.7668/hbnxb.2009.03.030
Abstract: 为明确中国东北地区水稻品种品质的特点,以2007年辽宁、吉林、黑龙江三省水稻区域试验品种(品系)为试材,在栽培管理水平高、有代表性的沈阳、公主岭、五常区试点,对三省穗上不同部位碾磨及外观品质进行比较.结果表明,辽宁省品种糙米率和整精米率均居于三省之首;辽宁省品种精米率较高,略高于黑龙江和吉林,但三省之间差异不显著;粒长和长宽比呈现黑龙江>辽宁>吉林的趋势;吉林白度高于辽宁,显著高于黑龙江;垩白度和垩白率均为吉林略高于辽宁,二省均极显著高于黑龙江.
桃幼胚离体培养再生植株的研究
国华,
园艺学报 , 2002,
Abstract: 以中晚熟桃品种‘京艳’、‘绿化9号’、‘晚蜜’和‘大久保’为试材,初步建立了桃体细胞胚发生和增殖的三阶段程序,即胚性愈伤组织诱导、体细胞胚发生和发育、体胚萌发成株以及次级体细胞胚的增殖。各品种体细胞胚的萌发成株率分别为73.5%、38.6%、5.4%和58.2%。用苯脲类细胞分裂素tdz有效诱导‘京艳’的幼胚子叶直接再生植株,再生率70%,平均每外植体不定芽数13.8个,再生不定芽生根后获得完整植株。
塔里木灌区膜下滴灌棉花水分生产函数及其效益
Water production function and efficiency of cotton under mulched drip irrigation


- , 2016, DOI: 10.7606/j.issn.1000-7601.2016.04.04
Abstract: 以2007—2012年塔里木灌区膜下滴灌田间灌溉试验数据为基础,采用最小二乘法原理,拟合了棉花的水分生产函数模型,分析并计算了棉花最高产量灌溉定额、最佳效益灌溉定额、高效用水灌溉定额,揭示了棉花的水分效应及需水规律。结果表明:塔里木灌区膜下滴灌棉花需水临界期是花铃期和蕾期;产量与耗水量、灌水量均呈良好的二次抛物线关系;合理灌溉定额为3 091~3 464 m3·hm-2,最高产量灌溉定额为3 464 m3·hm-2,高效用水灌溉定额为3 091 m3·hm-2;水资源投入的最佳效益点并非水分利用效率最高点和最高产量点,而是存在于3 091~3 464 m3·hm-2区间;当边际效益等于边际成本时,净收益最大,为24 333.1 元·hm-2,每立方灌水量净收益7.23 元·hm-2;现状条件下最佳效益灌溉定额为3 459 m3·hm-2,产量为6 360.7 kg·hm-2,与最高产量6 360.8 kg·hm-2基本相同,但比最高产量节水5 m3·hm-2,每立方灌水净收益增加0.21 元·hm-2,水分利用效率提高0.003 kg·m-3。
This paper discusses the relationship between the amount of irrigation and the yield of cotton. Statistical analysis of experimental data on cotton under mulched drip irrigation during 2007—2012 indicates that the relationship between yield of cotton and irrigation presents a quadratic parabola in Tarim irrigated area. The irrigation norms for the highest yield, for the highest water use efficiency, and for the highest benefits, and the critical period of water requirement in cotton were analyzed by mathematical method. Best fit model of cotton water production function was adopted by least squares theory on the basis of field experimental data of cotton. Water production function is a quadratic function and its math expression is Y=0.0026 I2+18.015I-24845 (R2=0.9592,n=6). Water productivity is divided into three different development stages according to the changing rule of water use efficiency and the relationship between yield and irrigation. Irrigation amounts less than 3 091 m3·hm-2 are identified as the first stage when yield rises with the increase of irrigation amounts, and productivity rises gradually at this stage. Irrigation amounts at the second stage rises from 3 091 m3·hm-2 to 3 464 m3·hm-2 and the yield still rises with the increase of irrigation amounts, but the range is reduced. Irrigation amounts at the third stage exceed 3 464 m3·hm-2 and the yield is reduced with the increase of irrigation amounts. Negative rise occurs and productivity is declined. The analysis of cotton irrigation production function and the water requirement law indicates that the critical periods of water application for cotton are at the flowering stage and budding stage. The rational irrigation norm, norm for the highest yield, and norm for the highest water use efficiency for cotton are 3 091 to 3 464 m3·hm-2, 3 464 m3·hm-2, and 3 091 m3·hm-2, respectively. The best benefits point of irrigation efficiency of cotton is not the highest point of utilization ratio of water or the highest point of yield, but within the 3 091~3 464 m3·hm-2 interval. When marginal benefit equals marginal
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