可移动中继节点在传感器网络中的节能应用

介绍了一种新颖的静态传感器网络实现方法，它利用可移动的中继节点来收集静态传感器网络的数据，有效的节约各传感器节点的能源，延长整个传感器网络的有效工作时间。也可以对该方法进行适当的改进，应用到某些实时性要求较高的场合中去。然后介绍了应用该原理实现的一个通讯协议。     

现代爆破理论及其新进展

爆破理论的研究历史，经历了三个不同的发展阶段，各阶段均有其代表性理论。文章介绍和分析了各爆破理论的要点及其优缺点以及最新进展情况，对工程爆破实践起着重要的指导意义     

近年我国区域水文研究的若干进展

我国区域水文学的研究是在解放后其正发展起来的。尽管迄今人们对区域水文学仍有不同的认识,例如区域水文学是否可以与水文地理学等同,或是区域水文学是否应隶属于区域地理学等等,但是作为水文学的分支学科是无疑的。区域水文学从整体的观点来研究区域水文情势。区城可以是功能区,如城市、出口加工中心区等,或为自然景观区,如干旱区、喀斯特区等,也可以是行政区。目前,许多水文水利工作者已在致力于区域水文学的研究。     

悼念郭敬辉同志

我国著名的水文地理学家、中国科学院地理研究所研究员郭敬辉同志于1985年4月5日溘然长逝。他的逝世是我国地理学界和水文学界的一大损失。我们怀着十分悲痛的心情对他表示沉重悼念。     

扬子及周缘地区上奥陶统-下志留统烃源岩发育环境及其控制因素

扬子地区下古生界发育了上奥陶统五峰组和下志留统龙马溪组两套有效烃源岩,查清其发育环境及其控制因素具有重要的科学理论和油气勘探意义.晚奥陶世开始,扬子地区进入碎屑岩陆棚演化阶段;五峰期-龙马溪期,扬子地区主体为局限的深水陆棚环境,总体呈现出浅水陆棚、深水陆棚、次深海共存的古地理格局.沉积体系展布和沉积演化主要受扬子陆块与华夏陆块的汇聚作用控制.扬子地区上奥陶统-下志留统烃源岩的形成与生烃母质生物的高生产力和高埋藏率、冰期-冰后期之交的气温快速转暖、海平面快速上升以及粘土矿物在有机质富集保存过程中的赋存驻留作用等密切相关.     

Impact of land use covers upon karst processes in a typical Fengcong depression system of Nongla, Guangxi, China

The direction and intensity of karst processes can be deeply affected by soil physical and chemical variations which were resulted from land use. Taking Nongla Fengcong depression area, Mashan County, Guangxi as an example, authors discussed the impact of land use on karst processes based on the data of field limestone tablet. The results showed that the corrosional rates at varied soil depth are quite different. Corrosional rate in woodland and orchard is mostly bigger than 20 mg/a, which is much higher than that in tilled land and shrub. Generally, corrosional rate decreased from orchard, woodland, tilled land, fallow land and shrub successively, in which soil organic matter (OM) and soil pH are two major controlling factors: corrosion process is controlled remarkably by soil OM in woodland and orchard. The higher the organic matter content is and the less the pH value is, the higher the corrosional rate is. Owing to lower organic matter content, the corrosional rate is mainly affected by soil CO₂ in tilled land and shrub.     

Recharge source and hydrogeochemical evolution of shallow groundwater in a complex alluvial fan system,southwest of North China Plain

Many cities around the world are developed at alluvial fans. With economic and industrial development and increase in population, quality and quantity of groundwater are often damaged by over-exploitation in these areas. In order to realistically assess these groundwater resources and their sustainability, it is vital to understand the recharge sources and hydrogeochemical evolution of groundwater in alluvial fans. In March 2006, groundwater and surface water were sampled for major element analysis and stable isotope (oxygen-18 and deuterium) compositions in Xinxiang, which is located at a complex alluvial fan system composed of a mountainous area, Taihang Mt. alluvial fan and Yellow River alluvial fan. In the Taihang mountainous area, the groundwater was recharged by precipitation and was characterized by Ca–HCO₃ type water with depleted δ¹⁸O and δD (mean value of −8.8‰ δ¹⁸O). Along the flow path from the mountainous area to Taihang Mt. alluvial fan, the groundwater became geochemically complex (Ca–Na–Mg–HCO₃–Cl–SO₄ type), and heavier δ¹⁸O and δD were observed (around −8‰ δ¹⁸O). Before the surface water with mean δ¹⁸O of −8.7‰ recharged to groundwater, it underwent isotopic enrichment in Taihang Mt. alluvial fan. Chemical mixture and ion exchange are expected to be responsible for the chemical evolution of groundwater in Yellow River alluvial fan. Transferred water from the Yellow River is the main source of the groundwater in the Yellow River alluvial fan in the south of the study area, and stable isotopic compositions of the groundwater (mean value of −8.8‰ δ¹⁸O) were similar to those of transferred water (−8.9‰), increasing from the southern boundary of the study area to the distal end of the fan. The groundwater underwent chemical evolution from Ca–HCO₃, Na–HCO₃, to Na–SO₄. A conceptual model, integrating stiff diagrams, is used to describe the spatial variation of recharge sources, chemical evolution, and groundwater flow paths in the complex alluvial fan aquifer system.     

A three-dimentional model of the northeast East China Sea, with application to the M2 current field

A simple three-dimensional tidal model is used to examine the M2 tidal current distribution in a northeastern part of the East China Sea, especially the vertical variation of the current in the region. Computed M2 current is compared with observations available and found to be in good agreement.Main features of the calculating method in this study are: (1) Vertical variation of the tidal current is taken as a funetion of the depth-mean velocity: (2) the method is applicable to a variety of the vertical eddy viscosities; (3) it has a fine vertical resolution, especially near the sea bootom. So, this method not only enables us to get a steady state solution easily but also depicts effects of the friction on the vertical variation of the current much better.     

Relationship between biogeochemical features of biogenic elements and flocculation in the Changjiang Estuary

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East-west oscillation of sea temperature in the Equatorial Pacific and its modelling

In this paper, by analyzing the data of sea temperature in the Equatorial Western Pacific (EWP), we found that the sea temperature at sensitive district (WSST) (about at 6° N, depth of 125-150 m) is correlated negatively to the sea temperature in the Equatorial Eastern Pacific (EEP). On the basis of basic characteristics of Equatorial Pacific atmosphere and ocean, we designed a simple air-sea coupled model. Using this model,an ocean circulation was simulated. The east-west oscillation of sea temperature in Equatorial Pacific is related to this ocean circulation.