南沙他国侵占岛礁战略价值及空间格局评价

从建岛潜力、岛礁辐射能力和岛礁承载能力3个方面选取26个指标,采用主客观综合赋权法确定各因子权重,利用线性加权法获得被越南、菲律宾、马来西亚、文莱等国所侵占的南沙44个岛礁的战略价值,并对结果进行空间插值,分析其空间格局特征。结果表明：1）被马来西亚侵占的弹丸礁、越南侵占的南威岛、以及菲律宾侵占的中业岛,其战略价值位列前3,评价得分分别为100、98.42和97.09。2）岛礁辐射能力空间分布格局呈现“NW—SE条带式”,“最高”和“高”等级的区域由研究区西北延伸至东南,然后向东北、西南两侧递减,辐射能力格局中有2个核心区域和2个次级核心区域。承载能力空间分布格局呈现“横向条带式”,由北向南越来越低,有1个核心区域和2个次级核心区域。建岛潜力空间分布格局有3个核心区域及2个次级核心区域。3）岛礁战略价值空间分布格局有3个核心区域,分布于研究区中部、北部及南部,与越南、菲律宾、马来西亚密切相关的核心区域各有1个。越南侵占岛礁最多且空间分布较广,有2个次级核心区域也与越南密切相关,越占岛礁若进一步建设,将形成多核心协同的战略格局,需密切关注。     

Accuracy evaluation of two precipitation datasets over upper reach of Heihe River Basin, northwestern China

As an important forcing data for hydrologic models, precipitation has significant effects on model simulation. The China Meteorological Forcing Dataset (ITP) and Global Land Data Assimilation System (G...     

珠江三角洲东部常平地区景观异质性研究

本文以１９８８年－１９９６年６个时段景观遥感类型图为主要信息源,利用信息熵法和空隙度指数法对珠江三角洲东部常平地区的景观异质性进行了研究。重点探讨了景观组分的空间分布差异和异质性动态变化情况。结果显示,开发区主要呈宏观异质性分布,果园,农田和林地呈微观异质性分布,城镇和水体的异质性分布特征均出现显著变化。     

西安翠华山古崩塌性滑坡体的沉积特征及其形成过程

西安翠华山风景地貌由古崩生滑坡体高速运行堆积而成,堆积体存在一些反映其运动和动力状况的沉积特征,将崩塌性滑坡体的平面堆积体划分出５个平面相带;中央相带、边缘相带、抛掷相带、气浪溅泥相带和特殊的残留相带,各带有不同的沉积特征,反映出调整运动中的崩塌式滑坡体动力过程和沉积过程在平面上分布的差异,通过研究该古积物的粒径变化、砾石组构和沉积结构、构造的差异,认为该崩塌式滑坡体在运动和沉积过程,存在前后部位     

广州市土地覆被格局异质性的尺度与等级特征

基于SPOT遥感数据源形成广州市土地覆被类型图,在中心城区选取互相垂直的南北和东西两条样带,用Fortran编程计算各样带在125m、250m、500m和1000m 4个幅度下的景观多样性指数,以及Moran I、Geary C系数和半变异函数。再将样带分别自北向南和自西向东等间距划分,形成一系列面积相等的区域,计算各区域以及样带整体上的多样性指数的尺度方差。结果表明,土地覆被景观多样性在不同的研究幅度下都存在正的空间自相关性,并具有方向性。尺度方差结果显示,尺度方差与尺度和幅度都有关,随着研究尺度增大,尺度方差都呈下降之势,而随幅度增大,尺度方差并非单调变化。如125m和250m两种幅度时,方差随着尺度增大而减少。尺度方差结果进一步揭示研究样带上土地覆被存在多尺度等级结构,并且具有方向性特点,同时也反映尺度方差不失为景观异质性研究的一种有效方法。     

The 144–140 Ma Mafic Dykes in North China and Northeast China Indicating Regional Extensional Tectonic Setting

<正>Objective Previous studies indicate that the North China Craton(NCC)had undergone the loss of thickened lithosphere and fundamental change of physical and chemical property of lithospheric mantle(the destruction of NCC)during the Mesozoic.The peak period of the destruction of NCC is estimated to be 130 Ma,accompanied by widespread metamorphic core complex,rift basins,A-type     

壳聚糖抑菌性能研究进展

壳聚糖又名甲壳胺,是甲壳素脱乙酰的产物,学名为1,4-2-氨基2-脱氧-β-D葡萄糖。壳聚糖来源于甲壳动物和昆虫的外骨骼,在地球上含量及为丰富。作为一种天然的多阳离子化合物,由于其具有良好的生物降解性、生物相溶性、无毒性和广谱抗菌性等特点,近年来越来越受到人们的重视,尤其在壳聚糖的抑菌方面,关于壳聚糖的抑菌机理抑菌效果和构效关系等方面都进行了大量的研究,由于壳聚糖的水溶性较差,限制了它的应用范围,根据这一特点,人们开始致力于其水溶性衍生物的开发和抑菌方面的研究与应用,取得了不少新的研究进展,为壳聚糖在抗菌方面的应用提供了大量的基础理论。作者就以上几个方面的问题进行了综述。     

Soil Respiration Dynamics and Influencing Factors in Typical Steppe of Inner Mongolia under Long-term Nitrogen Addition

We investigated soil respiration (Rs) dynamics and influencing factors under different nitrogen (N) addition levels (0, 2, 4, 8, 16, 32 g m^-2 yr^-1) on typical grassland plots in Inner Mongolia. We measured soil respiration, temperature, moisture and nutrients. We found that N addition did not change dynamic characteristics of Rs; daily and seasonal dynamics followed a single peak curve. N addition reduced Rs during the growing season. Rs under N2, N4, N8, N16 and N32 treatments decreased by 24.00%, 21.93%, 23.49%, 30.78% and 28.20% in the growing season, respectively, compared to the N0 treatment. However, Rs in the non-growing season was not different across treatments. Rs was significantly positively correlated with soil temperature and moisture and these two factors accounted for 72%-97% and 74%-82% of variation in Rs, respectively. The soil respiration temperature sensitivity (Q₁₀) was between 2.27 and 4.16 and N addition reduced Q₁₀ except in the N8 treatment.     

辽河三角洲地貌演化(英文)

This paper mainly analyzes the geomorphological changes of the tidal deposition in the Liaohe Estuary based on the multi-year bathymetric charts in 1990, 1996, 2002 and 2005 and Landsat TM images in 1987, 1994, 2002 and 2005. Evolution of the tidal depositional system during the past 20 years in the Liaohe River was studied on the basis of 50 boreholes drilling and 30 km shallow stratigraphic exploration from 2002 to 2005. The main tidal depositional body of the modern Liaohe River delta is located in the Shuangtaizihe Estuary. The stratum within the depth of 10 m includes tidal bank facies, tidal channel facies and neritic facies with paleo-delta facies underlying them. The sediments of tidal bank facies are mainly composed of sand and silt with siltation load and suspended load of about 50% respectively in proportion. The sediment of tidal channel facies and neritic facies is composed of clayey silt and silty clay which belongs to suspended load. The study area was a small bay between the old Daliaohe River, the old Dalinghe River and the Raoyanghe River complex delta since the Holocene to 1896. Many tidal banks formed and expanded rapidly after the Shuangtaizihe River was excavated by labor in 1896. The runoff and sediment discharge have decreased since the construction of brake at the Shuangtaizihe River in 1958.The Shuangtaizihe Estuary is in the state of deposition as a whole whose tidal bank is increasing and expanding southward, westward and northward. The maximum expansion speed is 87 to 683 m/a and the mean depositional rate is 0.189 m/a. Erosion occurred in some part of tidal bank with average erosional rate of 0.122 m/a. The tidal channel was filled up with sediment at a migration speed of 48–200 m/a. Geomorphologic changes have happened under the combined influences of runoff, ocean dynamics and human activities. The main source of sediment changes from river sediment to sediment driven by tidal current and longshore current.     

Simultaneous estimation of surface soil moisture and soil properties with a dual ensemble Kalman smoother

In this paper, a new state-parameter estimation approach is presented based on the dual ensemble Kalman smoother(DEn KS) and simple biosphere model(Si B2) to sequentially estimate both the soil properties and soil moisture profile by assimilating surface soil moisture observations. The Arou observation station, located in the upper reaches of the Heihe River in northwestern China, was selected to test the proposed method. Three numeric experiments were designed and performed to analyze the influence of uncertainties in model parameters, atmospheric forcing, and the model's physical mechanics on soil moisture estimates. Several assimilation schemes based on the ensemble Kalman filter(En KF), ensemble Kalman smoother(En KS), and dual En KF(DEn KF) were also compared in this study. The results demonstrate that soil moisture and soil properties can be simultaneously estimated by state-parameter estimation methods, which can provide more accurate estimation of soil moisture than traditional filter methods such as En KF and En KS. The estimation accuracy of the model parameters decreased with increasing error sources. DEn KS outperformed DEn KF in estimating soil moisture in most cases, especially where few observations were available. This study demonstrates that the DEn KS approach is a useful and practical way to improve soil moisture estimation.