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991.
Effect of reclamation time and land use on soil properties in Changjiang River Estuary,China 总被引:4,自引:1,他引:3
ülo MANDER 《中国地理科学(英文版)》2011,21(4):403-416
The objective of this study is to analyze soil physical and chemical properties,soil comprehensive functions and impact factors after different years of reclamation.Based on the survey data taken from 216 soil sampling points in the Fengxian Reclamation Area of the Changjiang (Yangtze) River Estuary,China in April 2009 and remotely sensed TM data in 2006,while by virtue of multivariate analysis of variance (MANOVA),geo-statistical analysis (GA),prin-cipal component analysis (PCA) and canonical correspondence analysis (CCA),it was concluded that:1) With the in-crease in reclamation time,soil moisture,soil salinity,soil electric conductivity and soil particle size tended to decline,yet soil organic matter tended to increase.Soil available phosphorous tended to increase in the early reclamation period,yet it tended to decline after about 49 years of reclamation.Soil nitrate nitrogen,soil ammonia nitrogen and pH changed slightly in different reclamation years.Soil physical and chemical properties reached a steady state after about 30 years of reclamation.2) According to the results of PCA analysis,the weighted value (0.97 in total) that represents soil nutrient factors (soil nitrate nitrogen,soil organic matter,soil available phosphorous,soil ammonia nitrogen,pH and soil particle size) were higher than the weighted value (0.48 in total) of soil limiting factors (soil salinity,soil elec-tric conductivity and soil moisture).The higher the F value is,the better the soil quality is.3) Different land use types play different roles in the soil function maturity process,with farmlands providing the best contribution.4) Soil physi-cal and chemical properties in the reclamation area were mainly influenced by reclamation time,and then by land use types.The correlation (0.1905) of the composite index of soil function (F) with reclamation time was greater than that with land use types (-0.1161). 相似文献
992.
郑智捷 《成都信息工程学院学报》2011,(6):579-589
研究0-1多元变量的逻辑函数及其整体配置函数空间变值编码表示特性。根据对称特性,系统地定义一批整体编码结构:邵雍-Leibniz码、广义码、文王码、伏羲码和共轭码。展示变值向量配置函数空间规模以及函数群集的状态空间组织结构。对各类编码系列的可区分数目,给出计算公式。2维变值展示框架展现在变值配置函数空间中不同编码族具有的内蕴对称特性。分层结构编码配置函数空间和2维展现描述体系,为基于东方逻辑传统的现代逻辑架构:变值逻辑体系,利用高维分析工具探讨0-1序列非线性超复杂逻辑变换开辟道路。 相似文献
993.
在不同的天气条件下,由于气溶胶对光波的散射作用,通过成像系统获得的图像都会有一定程度的退化。利用图像的退化模型可以获取与天气现象相关的参量,从而达到识别天气的目的。对不同天气条件下得到的同一场景图进行研究,运用多垂线检测法,检测出不同天气条件下直线模糊边缘上的灰度值,采用signloid函数拟合出刃边函数,进而求出线扩散函数。通过分析线扩散函数的变化规律,总结出其与天气现象之间的紧密联系。测试结果表明,应用该方法对于晴天、薄雾、雨、霾、沙尘暴等天气现象具有一定的判别效果。 相似文献
994.
基于小波变换的稳定性函数来研究尺度进制的算法。用母波的频谱函数来构造出尺度进制为任意进制时的稳定性函数,根据稳定性函数计算小波框架的边界、紧致度和收敛因子,最后由框架参数值进一步计算得到尺度进制范围。结果表明,此范围有效地缓解了小波变换的稳定性和冗余性之间的矛盾。 相似文献
995.
996.
基于主体功能区视角的县域规划创新研究 总被引:1,自引:0,他引:1
县域是我国主体功能区划分和规划落实的基本空间单元。主体功能区理念促进了县域规划思路的转型、创新,实现了县域规划由经济导向型、上级指令型、政府主导型、部门分割型和社会经济发展管治型向多目标综合协调型、刚性与弹性兼容并蓄型、双向互动互求协商型、主体功能定位导向型和空间协调管治型的转变。进而依据主体功能定位不同,从空间模式、产业导向、城镇体系、基础设施、生态支撑和规划考核等方面重构了县域规划内容体系,并以新沂市为例对限制型开发县域规划相关理论进行了进一步论证,最后依据主体功能区的分类特征有针对性地提出了实施县域规划的保障措施。 相似文献
997.
Analysis of teleseismic records obtained in two broadband seismic stations of three components located on the Andean region of Colombia is presented in this work. The two stations are located at the Western Cordillera (WC), station BOL, and at the Central Cordillera (CC), station PBLA. The analysis of seismograms was performed by inversion of the receiver functions (RF) in order to obtain the crustal velocity structure beneath the receivers. The receiver function is a spectral ratio obtained from teleseismic earthquakes recorded by broadband seismic stations, which allows the calculation of the velocity structure beneath the receiver by removing source effects in the horizontal components of the seismic traces. Data stacking was performed in order to improve signal to noise ratio and then the data was inverted by using two optimization algorithms: a genetic algorithm (GA), and a simulated annealing algorithm (SA). The present work calculates the receiver functions using teleseismic earthquakes at epicentral distances (Δ) ranging between 30° and 90° and recorded at the two stations within the years 2007 and 2009.Delay times between P and PS waves converted at the Moho boundary were used to constrain the velocity structure. The receiver functions at the stations were generated from seismic events within a broad range of back azimuth. Data from gravity and magnetism were also used during the geophysical survey. The depth of the Moho boundary was found to be at 40 km in the WC beneath station BOL and at 43 km in the CC beneath station PBLA. The upper crust, with a thickness of 5 km, is characterized by a shear wave velocity of about 3.0 km s−1; the shallower layers, at approximately 1.0 km, have shear wave velocities between 2.2 and 2.6 km s−1, which corresponds to sediments overlying the upper crust. These observations support the hypothesis of a thickness of the crust at the root of the mountain range to be between 32 and 50 km. The calculated receiver functions were compared with artificial ones generated from the inversion of 48000 models of horizontal layers for each station using a GA and an SA that allowed a satisfactory coverage of all the sample space in order to avoid non-unique solutions. Beneath station BOL a moderate low-velocity zone (LVZ) was found, which was caused by accretionary processes of the ophiolite complex in the WC. 相似文献
998.
利用由科尔沁沙地榆树区域综合年表而重建的181a降水序列,采用均生函数-最优子集回归(MGF-OSR)预测模型对科尔沁沙地降水进行了5a情景的预测,克服了以往序列短的不足.模型建模期相对误差绝对值在3%、5%、10%以内的年数分别占建模年数的36.46%、64.64%、93.37%,建模期模拟精度较高.2007~2010年实测检验期,模拟与实测值保持了方向一致性,各年份相对误差绝对值分别为11.40%、6.73%、22.06%、5.49%,大部分年份预测较理想.经预测,2011~2015年期间,2011年、2012年、2014年和2015年为降水正常年份,2013年为降水偏干年份.与实际情况对比,2011年与预测一致,2012年稍有差别.总体上,2011~2015年降水变化较为平缓. 相似文献
999.
多元均生函数模型及其在短期气候预测中的应用 总被引:6,自引:3,他引:6
在原均生数模型的基础上,对模型进行改进,首次引入预报因子变量,建立一个多元的均生函数模型。它适应于气温、降水、热带气旋个数等多种要素预报。新建的多元均生函数模型包含了原模型的优点。而且比原有均生函数模型具有更物理基础。 相似文献
1000.