塔里木河流域生态环境恶化的水文效应

塔里木河是我国最大的内陆河。 4条源流出山口多年平均天然径流量 2 2 4 .9× 10 8m3 (195 7～ 2 0 0 1年 )。在全球变暖的大背景下 ,塔里木河流域山区气候出现变暖增湿的趋势 ,2 0世纪 90年代径流量达 2 4 1.9× 10 8m3 ,增幅 7.6 %。由于源流区人类开发利用水资源的影响 ,使得补给塔里木河干流的水量不断减少 ,水文条件改变 ,造成干流上、中游段耗水严重 ,导致下游生态与环境急剧退化。自 2 0 0 0年以来 ,实施的从开都河—博斯腾湖向下游绿色走廊应急输水 ,已使下游生态环境开始恢复生机。     

A coat protein transgene from a Scottish isolate of potato mop-top virus mediates strong resistance against Scandinavian isolates which have similar coat protein genes

Resistance tests were made on seedlings of transformed lines of Nicotiana benthamiana which contain a transgene encoding the coat protein (CP) gene of a Scottish isolate of potato mop-top virus (PMTV). This transgene has been reported to confer strong resistance to the PMTV isolate from which the transgene sequence was derived and also to a second Scottish isolate. Plants of lines of the transgenic N. benthamiana were as resistant to two Swedish and two Danish PMTV isolates as to a Scottish isolate, and of five lines tested, greater than 93.5% of transgenic plants were immune. The coat protein gene sequences of these four Scandinavian isolates were very similar to those of the two Scottish isolates. The greatest divergence between the isolates was three amino acid changes and there was less than 2% change in CP gene nucleotide sequence. It is concluded that the PMTV CP transgene used in these experiments could confer resistance against isolates from different geographical areas because it is becoming apparent that the CP genes of PMTV isolates are highly conserved.     

Isolation of two strains of a new Tombusvirus (Havel river virus, HaRV) from surface waters in Germany

Two virus isolates from water samples — one from a small stream in South Western Germany and another one from the Havel river in North Eastern Germany c. 500 km away, proved to be strains, named S and H, respectively, of a new Tombusvirus for which the name Havel river virus (HaRV) had been suggested previously in a brief account. Immunoelectron microscopical decoration tests and sequence comparisons of the coat proteins indicated that the two HaRV strains are only distantly related to known Tombusviruses. The closest relationships were found to Cucumber necrosis virus. Nothing is known about their natural hosts. Because the S strain of HaRV was isolated in a woody area from a small stream close to its origin, they may be pathogens of trees or wild plants in such habitats.     

径流资料缺乏地区水资源配置研究——以都匀市为例

水资源合理配置是解决水资源分配不均,缓解水资源供需矛盾,提高水资源利用效率的有效途径。然而由于缺乏实测径流资料,区域无法合理量化乃至分配水资源,造成缺乏与浪费并存的现象。为此,以都匀市为例,利用清水江下游黔南州下司水文站的实测资料构建了SWAT分布式水文模型,通过相关系数及纳西效率系数验证了模型的精度,得到了可用作水资源配置基础资料的都匀市境内各干支流长系列流量数据。通过量化水资源系统中各部门的供需并连接相关关系,建立了基于水量平衡的WEAP水资源配置模型,并预测了现状2010年至远景2030年的区域水资源供需平衡情况。结果表明:针对径流资料缺乏地区,应用水文模型模拟径流数据进行水资源配置的方法,能够定量分析不同供需情况下的水资源分配矛盾,可以为区域水资源管理及社会可持续发展规划提供指导。     

Practical Method of High-Speed Access for Medical Digital Image Sequences

The high-speed access for medical digital image sequences was restricted to special device and complicated system in the past. The authors present a new method of high-speed access for medical digital image sequences which can be performed on general computer by means of the combination of Serial ATA(SATA) and Redundant Array of Independent Disk(RAID).Then they introduce the scheme of system configuration and software program. Lastly the testing result is given and the speediness,cheapness and conveniency of this method are elucidated.     

沿渡河流域分布式水文模型的构建

按照综合分布式概念性水文模型和分布式水文物理模型长处的建模思路，应用改进的格林-安普特下渗理论和地貌水文学的水滴运动理论，建立了一个具有物理基础的松散结构分布式流域水文模型。模型的产流方法融合了邓恩产流理论和霍顿超渗产流理论，考虑土壤水分剖面、土壤各向异性和地形坡度等对流域产流的影响；模型的汇流方法利用地貌水文学理论，寻求水文过程与流域地形地貌的相互作用及定量关系，以确定模型参数，其优势在于可以考虑净雨空间分布不均和流速空间分不均对流域汇流的影响问题。以湿润地区典型流域沿渡河为对象进行水文模拟应用研究，结果良好,说明模型较为可靠。     

基于DEM的水文模型在沮河流域的应用

基于DEM的流域水文模型是近年来水文模型的热点,而干旱半干旱地区的水文模型一直是水文研究的一个难题。分析了干旱地区的降雨产流特性,建立了符合该产流特性的数字高程模型和陕北模型相结合的水文模型,并将其应用到沮河流域桃曲坡水库的洪水预报中,计算结果证明该水文模型在干旱地区是切实可行的。     

新疆阿图什哈拉峻地区地下水系统分析

通过对阿图什哈拉峻地区水文地质特征和地下含水系统各子系统间关系分析,采用系统分解合成方法,将地下水系统分解为北部单一潜水系统和南部上层潜水、下部承压水子系统,在合理耦合各子系统基础上,建立了该地区地下水系统的数学模型。采用有限元方法对该模型进行数值离散,经DevelopStudio编程,利用潜水、承压水模拟与实测结果的比较,在得到该地区地下水系统的水文地质参数的同时,重点研究了各系统间水量交换关系,为地下水系统的合理开采利用提供了理论基础和科学数据。     

GIS在分布式水文模型中的应用——以北京雁栖河流域为例

在GIS支持下,由北京雁栖河流域数字高程模型DEM自动生成子流域单元,每个子流域单元的降雨径流过程利用一个水箱模型来模拟,该水箱模型用一个两参数的非线性分布函数来模拟上土壤层的蓄水容量空间分布特征,计算每个子流域单元TOPMODEL模型地形指数ln(a/tanβ)的空间累积分布曲线,并对其作无量纲化处理,通过地形指数ln(a/tanβ)的空间累积分布曲线的无量纲化曲线的最佳曲线拟合确定每个子流域单元土壤蓄水容量空间变异性参数,这使得模型中的土壤蓄水容量空间变异性参数成为一个有确定物理意义的参数,也使得所建立的模型更加具有物理基础。结果表明:无论从模型的率定期还是从模型的验证期来看,模型计算的径流与实测的日径流过程线都呈现出很好的一致性和吻合性,这说明本文建立的模型对雁栖河流域的日径流量的分布式模拟是有效的。     

元阳梯田核心区不同土地利用类型土壤水文效应研究

为了揭示元阳梯田区森林土壤涵养水源的机理,采用双环法和环刀法等,对元阳梯田核心区有林地、灌木林地、荒草地和坡耕地的持水性能及孔隙情况等进行了研究。结果表明:土壤的质地和有机质对土壤的持水量有重要影响;有机质对土壤持水能力产生直接影响,有机质含量越多,土壤的持水能力越强;质地对土壤的持水能力产生间接影响:灌木林地土壤的持水量最大,深度0—20cm的灌木林地土壤的总持水量为1 404.8t/hm2;土壤的初期含水量对土壤的初渗速率有较大影响,4种土地利用类型中以荒草地的初渗速率为最大。由结果可知,元阳梯田区森林具有持水能力强、入渗特性好的特点,充分发挥了森林调节水文的功能。