GIS模型在淤地坝规划中的应用

随着淤地坝建设规模的和数量的不断扩大，对其规划的科学性和效率要求越来越高。应用在淤地坝规划中的GIS模型能够解决传统淤地坝规划中的难点。提高淤地坝规划的精度和效率，将成为淤地坝规划的发展方向。     

流域模拟模型与GIS集成研究现状与展望

综述了流域模拟模型的现状和发展.从数据集成的角度,把流域模拟模型与地理信息系统集成方法归纳为互连式、共连式、流域模拟模型嵌入GIS和GIS嵌入流域模拟模型四种类型,讨论了各类集成方法的技术特点、应用和优缺点;并从数据、GIS技术、流域模拟模型和研究人员四个方面分析了流域模拟模型与GIS集成存在的问题;最后指出基于数字流域的综合集成方式将是流域模拟模型与GIS集成的发展方向.     

GIS在水土保持工作中的应用

利用地理信息系统的采集、存储、管理、显示与应用功能及其他计算机硬、软件技术,使地理信息系统在水土保持工作特别是在土壤空间分布调查、土壤侵蚀量估算、土壤侵蚀时空模拟、水土保持规划设计、水土保持规划效果虚拟等研究中得到应用。研制开发了适用于土壤侵蚀及水土保持规划、管理的专业型GIS,随着组件软件技术的发展及GIS的二次开发,GIS将会在水土保持方面得到更多、更广泛的应用。     

基于数字流域的淤地坝规划减水减沙效果模拟

减水减沙是淤地坝的主要作用,也是评价淤地坝效益的重要指标。以往淤地坝减水减沙效益的评估方法主要是水文法,对实测资料的依赖性强,在淤地坝规划阶段,尚不能提供建坝后的实测水沙资料,采用水文法存在困难。基于数字流域模型,提出了一种淤地坝减水减沙效益评估方法,将减水减沙效益分析提前到淤地坝规划阶段,这为评价淤地坝规划方案的优劣提供了科学的依据,是淤地坝规划的一个重要步骤。     

对黄土高原淤地坝建设的几点认识和建议

黄土高原淤地坝建设有 40 0多年历史 ,新中国成立后得到大力发展。至 2 0 0 2年底 ,黄土高原地区已建成淤地坝 11 3 5万座 ,取得了巨大建设成就 ,在拦泥减沙、发展生产和改善生态环境等方面都发挥着不可替代的作用 ,但同时也存在着一些不容忽视的问题。在新形势下 ,应提高对淤地坝建设的再认识 ,抓紧做好黄土高原淤地坝规划 ,规范设计施工技术 ,尝试新的建设体制 ,正确处理几个关系 ,推动淤地坝建设快速、健康发展     

黄土高原沟壑区淤地坝泉眼封堵技术的探索与实践

随着黄土高原地区淤地坝坝系建设的规模推进,淤地坝坝址泉眼封堵直接影响着坝系建设的布局,坝址泉眼封堵技术成为了坝系建设中必须解决的重要技术问题。通过在庆阳市西峰区淤地坝建设中的施工实践,对黄土高原沟壑区淤地坝坝址泉眼封堵技术进行了有益的探索。     

基于神经网络的元胞自动机支持下的干旱区LUCC模拟研究——以新疆于田绿洲为例

元胞自动机已被广泛应用于城市发展变化的模拟研究中，但多数应用局限于两类土地利用类型的转变。借助神经网络中的BP算法，以遥感和GIS技术为依托，在对TM影像分类的基础上，应用GIS技术提取一系列LUCC空间影响因子，建立了模拟土地单元转变概率的BP神经网络模型。并以模拟的概率值代替CA模型的若干规则，对于田绿洲LUCC做了动态模拟。结果显示，该方法在干旱区复杂土地利用动态变化模拟中具有一定精度，能够对土地资源的可持续利用规划提供有用信息。     

黄土高原小流域坝系建设存在的问题及建议

从小流域淤地坝建设中土壤侵蚀模数的应用、淤地坝对沟道侵蚀的系统影响、淤地坝的可持续利用、土壤侵蚀控制等方面分析了现行淤地坝规划、设计和施工中存在的问题和不足,并提出了加强对小流域土壤侵蚀快速评估方法研究及相关成果的推广应用、加强对淤地坝减蚀作用的机理及其对小流域侵蚀环境系统影响分析研究、研究和改进现行的淤地坝设计施工方案等建议。     

黄土高原小流域淤地坝监测

[目的]为了探索小流域淤地坝监测的内容、指标、方法,分析淤地坝建设效益,更好地为淤地坝规划、建设、运行管理服务。[方法]2005—2010年,在黄土高原不同水土流失类型区选择了12条典型小流域坝系,布设监测点,采用遥感、水沙观测、调查等方法,连续开展淤地坝工程建设动态、拦沙蓄水、坝地利用及增产效益、坝系工程安全等监测。分析了淤地坝建设与坝系配置、坡面治理、拦沙蓄水、坝地利用等之间的关系。[结果]小流域淤地坝坝系在拦截泥沙、蓄洪滞洪、减蚀固沟、增地增收、促进农村生产条件和生态环境改善等方面发挥了显著的生态、社会和经济效益。[结论]建议在淤地坝建设中以小流域为单元,以骨干坝为主体,骨干坝、中型坝、小型淤地坝相结合,形成稳定的淤地坝坝系。     

互助县淤地坝建设及运行管理模式

1996年以来,互助县淤地坝建设经历了从单坝工程到坝系工程的跨越式发展,截至2011年年底,共建成各类淤地坝119座。根据互助县的实际情况,总结了淤地坝建设和淤地坝防汛体系建设的经验,以及4种常用的淤地坝运行管理模式,即流域管理所管理模式、承包经营管理模式、实体管理模式、护坝田补偿模式,希望能为黄土高原丘四区青海东部干旱区淤地坝后续建设以及农村生态改善、经济发展提供参考与借鉴。     

Physical Properties of the Soils of Sibay City of the Republic of Bashkortostan

Eurasian Soil Science - The results of the study of the properties of urban soils of the city of Sibay located in the mining region of the Republic of Bashkortostan are presented. A specific...     

食用仙人掌萎蔫气象条件分析

塑料大棚内种植的食用仙人掌在土壤墒情较好时也有萎蔫现象发生，通过试验观测和对仙人掌生理习性的分析，发现阴雨过后天气突然放晴温度急剧上升易使仙人掌发生萎蔫现象，并提出了田间管理的应对措施。     

Heterogeneity of Organic Matter of Aggregates of Protocalcic Chernozems

Eurasian Soil Science - Layers were step-by-step removed from macroaggregates (2–1 mm in diameter) of Protocalcic Chernozems via successive abrasion in a revolving rotator during 5, 10, 15,...     

青海省耕地资源开发利用分析及对策研究

分析论述了青海省耕地资源开发利用的现状、特点和问题。在此基础上,提出了对青海省耕地资源进行研究的框架体系和思路,同时基于GIS/RS技术设计了相关的技术路线。最后依据所做设计对青海省耕地资源开发利用做了初步分析,并进行了相关的对策研究分析。     

Characterization of physical and chemical properties of Varzea soils of Goias State of Brazil

Abstract

Brazil has approximately 30 million hectares of lowland areas, known locally as “Varzea,”; distributed throughout the country. Soils in these areas have the potential to support agricultural production, but very little is known about their fertility. The current experiment was undertaken to characterize the chemical and physical properties of representative “Varzea”; soils collected at 0–20, 20–40, 40–60, and 60–80 cm depth intervals from 23 sites in Goias State of Brazil. Organic matter contents averaged 42 g/kg in the surface 20 cm of soil and should make a significant contribution to overall nutrient availability. Soil pH increased slightly with depth from a mean value of 5.2 in the surface 20 cm of soil to a mean value of 5.4 in the 60–80 cm depth interval. Several soils had exchangeable Al values ≥ 1.0 cmol Al/kg, but soil Al saturation was generally less than the 60% level frequently associated with Al toxicity. However, cereal and legume production could benefit from lime addition in many of these soils. Although base saturation was fairly low in some soils, exchangeable Ca and Mg levels were, in general, adequate throughout the profile. Extractable P levels were adequate in most surface soil samples. Extractable K levels in these soils were generally low, and the application of K fertilizers should be beneficial, especially in conjunction with lime addition. The high clay content “Varzea”; soils of the Brazilian lowlands have some drainage problems but generally exhibit favorable chemical properties for crop production when compared to soils of the well‐drained Cerrados.     

Estimation of potential nitrogen-fixing activity of agrophytocenoses soils of the subtropical zone of Russia

An estimation of potential nitrogen-fixing activity of various soil types under agrophytocenoses of tea, filbert, peach, and pawpaw which grow in the area of Greater Sochi is given. High indicators of nitrogen fixation activity in the soil in the course of vegetation were characteristic of agrocenoses of pawpaw, peach, and filbert. The lowest level of nitrogen fixation was noted in the soil of a tea plantation. A negative correlation dependence of potential nitrogen-fixing activity on the acidity of the soil solution was established. A study of the seasonal dynamics of the activity of nitrogen fixation of soils of agrocenoses of the subtropical zone of Russia made it possible to distinguish a less active winter and more active spring-summer-autumn periods.     

物联网安全及解决措施

物联网是一个集信息通信、数据交换、传感器技术与软件工程于一体的综合性产业,探讨和分析了物联网的结构体系与发展中遇到的安全问题。     

荔枝种子结构的扫描电镜观察

荔枝种子从果实中剥离出来后, 即使在室内条件下, 也极易失水干缩, 潮湿环境中又易发霉而腐烂。扫描电镜观察表明: 种皮上布满纹孔, 水分散失面积很大; 种脐部为疏松的海绵组织, 且营养丰富。据此, 生产上应对种子彻底清洗, 并保存于适当湿度的环境中, 以提高其发芽率。     

Kinetics of Popping of Popcorn

The rate of popping of popcorn was measured in oil and in air. Kinetic data for lifetimes of individual kernels from a large population were obtained in oil at six constant temperatures (180–250°C) and also in an air‐popper at 202°C. The data are characterized by an induction period, which is, significantly, followed by a first‐order decrease in the number of unpopped kernels versus time. The activation energy for the first order process is 166.7 kJ/mol between 180 and 210°C, and 53.8 kJ/mol between 210 and 250°C. These data are consistent with a model that assumes 1) that the rate of heat transfer into a kernel follows Newton's law of cooling; 2) that in a sample of kernels there exists a distribution of critical pressures; 3) that for an individual kernel, the probability of popping is directly proportional to the difference between the internal aqueous vapor pressure and the kernel's critical pressure; and 4) that the measured rate constant at any temperature is an average overall of the kernels in the sample with critical pressures equal to or less than the internal aqueous vapor pressure. Minimum popping temperatures predicted by the model are 181 ± 2°C (oil) and 187 ± 2°C (air), in good agreement with previously reported direct measurements.     

三门峡水库库岸坍塌成因分析与防治措施研究

三门峡水库自1960年9月蓄水运行以来,库岸坍塌现象频繁发生,平均每年塌岸0.5～0.7亿m3.指出了造成库岸坍塌的原因主要是地质环境的影响以及水力条件的变化;不同的地形、地貌、地质结构和岩性特征,表现了不同的塌岸强度,其中黄土塬区为极强塌岸段,黄河Ⅱ级阶地为强烈塌岸段,黄河Ⅰ级阶地为中等强烈塌岸段;分析了引起库岸坍塌的主要水力条件有大气降水、地表水和地下水,并且不同水力条件及其变化特征,对库岸坍塌影响的方式和程度也不同;最后给出了防治库岸坍塌应采用标本兼治的原则,治标是指对塌岸进行必要的加固、支挡、衬砌等;治本就是根据引起塌岸的原因以及不同地质环境条件下的塌岸特征和水力条件,因地制宜,因害设防,从根本上进行综合治理.