安徽省地电阻率台址电性结构特征参数的初步分析     

王燚坤  隆爱军  张有林  曹晓星  陈远东  陈海博  陆立 《地震地磁观测与研究》2011,32(2):25-30

依据电测深资料,计算研究安徽省合肥、肥东、蒙城3个地电阻率台站的电性结构特征参数:干扰系数α、γ和异常系数β.讨论不同电性结构、不同极距、不同测线下特征参数的变化速率及相互之间的比例关系.研究结果表明,特征参数可以直观反映台址不同极距下的抑制干扰能力和映震能力,并对提升观测效能具有一定的指导意义.  相似文献   

安徽地区地磁转换函数变化与地震的关系     

周琼  曹志磊  夏仕安  李军辉  陈俊  金艳  隆爱军 《地震地磁观测与研究》2011,32(5):54-59

利用安徽省地磁台站2007-2009年数字化观测资料,应用地磁转换函数方法,对华东地区ML4.0以上地震进行对应关系研究,发现不同台站、不同周期的转换函数参量与安徽及邻近地区地震存在一定的对应关系,为今后数据研究提供参考.  相似文献   

Stock discrimination of spottedtail goby (Synechogobius ommaturus) in the Yellow Sea by analysis of otolith shape   总被引：1，自引：0，他引：1  

王英俊  叶振江  刘群  曹亮 《中国海洋湖沼学报》2011,29(1):192-198

Otolith shape is species specific and is an ideal marker of fish population affiliation. In this study, otolith shape of spottedtail goby Synechogobius ommaturus is used to identify stocks in different spawning locations in the Yellow Sea. The main objectives of this study are to explore the potential existence of local stocks of spottedtail goby in the Yellow Sea by analysis of otolith shape, and to investigate ambient impacts on otolith shape. Spottedtail goby was sampled in five locations in the Yellow Sea in 2007 and 2008. Otoliths are described using variables correlated to size (otolith area, perimeter, length, width, and weight) and shape (rectangularity, circularity, and 20 Fourier harmonics). Only standardized otolith variables are used so that the effect of otolith size on the shape variables could be eliminated. There is no significant difference among variables of sex, year, and side (left and right). However, the otolith shapes of the spring stocks and the autumn stocks differ significantly. Otolith shape differences are greater among locations than between years. Correct classification rate of spottedtail goby with the otolith shape at different sampling locations range from 29.7%–77.4%.  相似文献   

Otolith chemical signatures of spottedtail goby Synechogobius ommaturus in coastal waters of China     

��Ӣ��  Ҷ��  ��Ⱥ  ��Ρ��  ����  ��ΰ 《中国海洋湖沼学报》2011,29(3):640-646

This study explores the potential existence of local stocks of Synechogobius ommaturus using otolith chemical signatures. The concentrations of 10 elements (K, Ca, Na, Mg, Sr, Pb, Ba, Mn, Co, Zn) in the otoliths from eight stocks (Dandong, Dalian, Tianjin, Dongying, Weihai, Qingdao, Ganyu and Xiamen) of S. ommaturus were measured by Inductively Coupled Plasma Mass Spectrometry and regressed against otolith weight. No significant correlation between otolith weight and concentrations of Na, Mg, Ca, Sr, Co, Ba, Zn and Pb were observed. Concentrations of K and Mn were correlated with otolith weight. Consequently, the residuals of the regressions were used instead of the original concentrations in subsequent analyses. Analysis of variance (ANOVA) showed no significant difference between males and females in otolith chemical signatures. Differences were found among the locations for K, Sr, Mn, Co, Ba, Pb, but not for Ca, Na, Mg and Zn. Residuals of the regressions of elemental concentrations against otolith weight that fitted the normal distribution and homogeneity were studied by discriminant analysis. The success of the discriminant function to predict the location of S. ommaturus capture ranged from 100% for Weihai and Xiamen stocks, to only 44.4% and 62.5% for Qingdao and Dandong stocks, respectively. The average prediction success was 80.3%.  相似文献   

Spatial-temporal pattern and differences of land use changes in the Three Gorges Reservoir Area of China during 1975�C2005     

Yingui Cao  Wei Zhou  Jing Wang  Chun Yuan 《山地科学学报》2011,8(4):551-563

Regional land use changes are an important part of global changes. The research on land use changes in the Three Gorges Reservoir Area of China attracts a lot of attention owing to the Three Gorges Dam building. The Three Gorges Reservoir Area becomes one of the important research areas. This study analyzed the transforming processes and traits of each land use type and the regional differences of land use changes during the past 30 years, summarized the distribution of different land use types in different buffer zones and regresses the equation areas and different buffer distances based on buffer analyses and regression analyses, and then analyzed the transforming rules in different buffer distances, got the optimal influence distances. The research results indicate that, (1) cultivated land lies at the northwest of the reservoir and was decreasing, however, the construction land was increasing, especially the urban construction land, a large number of land was flooded because of the reservoir water level rise; (2) urban area was sprawling quickly in developed and neighboring areas, and a great deal of cultivated land and a considerable amount of grassland were occupied; in the earlier time, rural settlements occupied lots of cultivated land and a sum of forestry land in the later time; (3) the optimum influenced distances for cultivated land and forestry land were 10–35 km, and for urban and rural settlements were in 5–20 km. Overall, this research can reflect the spatial-temporal characteristics of land use changes during the 30 years, and it is helpful for urban planning and land use planning in the reservoir area.  相似文献   

河南省农作物虚拟水含量时空分异特征     

黄会平  曹明明  宋进喜  韩宇平  陈姗姗 《地域研究与开发》2015,(3):167-171,176

在GIS技术的支持下,通过对1978—2013年河南省冬小麦、夏玉米、花生、棉花、油料作物、蔬菜6种主要农作物虚拟水量的计算与分析,探讨了其时空分异规律。河南省6种农作物单位质量虚拟水量在不断下降的趋势下有波动,2003年出现峰值,与当年大旱、所有农作物大面积减产有关;在农作物类型中,棉花单位质量虚拟水含量最高,多年平均值达到8 077.4 m3/t,蔬菜最低,多年平均值仅为159.95 m3/t。6种作物的虚拟水含量在空间分布上有明显差异,按其2013年的产量进行加权分析得到,第一等级区域为三门峡、郑州、信阳,第二等级为平顶山、洛阳、济源、开封,第三等级为南阳、驻马店、新乡、鹤壁、安阳、濮阳,第四等级为漯河,最低为许昌、周口、商丘、焦作。从整体看,西部、南部虚拟水含量高,而北部、东部虚拟水含量低。  相似文献   

Exploring hyperspectral bands and estimation indices for leaf nitrogen accumulation in wheat     

Xia Yao  Yan ZhuYongChao Tian  Wei FengWeiXing Cao 《International Journal of Applied Earth Observation and Geoinformation》2010

Hyperspectral sensing can provide an effective means for fast and non-destructive estimation of leaf nitrogen (N) status in crop plants. The objectives of this study were to design a new method to extract hyperspectral spectrum information, to explore sensitive spectral bands, suitable bandwidth and best vegetation indices based on precise analysis of ground-based hyperspectral information, and to develop regression models for estimating leaf N accumulation per unit soil area (LNA, g N m⁻²) in winter wheat (Triticum aestivum L.). Three field experiments were conducted with different N rates and cultivar types in three consecutive growing seasons, and time-course measurements were taken on canopy hyperspectral reflectance and LNA under the various treatments. Then, normalized difference spectral indices (NDSI) and ratio spectral indices (RSI) based on the original spectrum and the first derivative spectrum were constructed within the range of 350–2500 nm, and their relationships with LNA were quantified. The results showed that both LNA and canopy hyperspectral reflectance in wheat changed with varied N rates, with consistent patterns across different cultivars and seasons. The sensitive spectral bands for LNA existed mainly within visible and near infrared regions. The best spectral indices for estimating LNA in wheat were found to be NDSI (R₈₆₀, R₇₂₀), RSI (R₉₉₀, R₇₂₀), NDSI (FD₇₃₆, FD₅₂₆) and RSI (FD₇₂₅, FD₅₁₆), and the regression models based on the above four spectral indices were formulated as Y = 26.34x^1.887, Y = 5.095x − 6.040, Y = 0.609 e^3.008x and Y = 0.388x^1.260, respectively, with R² greater than 0.81. Furthermore, expanding the bandwidth of NDSI (R₈₆₀, R₇₂₀) and RSI (R₉₉₀, R₇₂₀) from 1 nm to 100 nm at 1 nm interval produced the LNA monitoring models with similar performance within about 33 nm and 23 nm bandwidth, respectively, over which the statistical parameters of the models became less stable. From testing of the derived equations, the model for LNA estimation on NDSI (R₈₆₀, R₇₂₀), RSI (R₉₉₀, R₇₂₀), NDSI (FD₇₃₆, FD₅₂₆) and RSI (FD₇₂₅, FD₅₁₆) gave R² over 0.79 with more satisfactory performance than previously reported models and physical models in wheat. It can be concluded that the present hyperspectral parameters of NDSI (R₈₆₀, R₇₂₀), RSI (R₉₉₀, R₇₂₀), NDSI (FD₇₃₆, FD₅₂₆) and RSI (FD₇₂₅, FD₅₁₆) can be reliably used for estimating LNA in winter wheat.  相似文献   

同步辐射标定平面镜反射率不确定度分析方法研究   总被引：1，自引：0，他引：1  

陈伯伦  杨正华  曹柱荣  董建军  侯立飞  崔延莉  江少恩  易荣清  李三伟  刘慎业  杨家敏 《海洋学报》2010,32(10):7078-7085

为了提高多通道软X射线能谱仪的测量精度,2009年在北京同步辐射(BSRF)软X束线源上对多种材料的掠入射平面镜的反射率进行了标定.在标定实验的基础上,对光源的单色性、高次谐波以及源强稳定性、探测器响应一致性和数据采集统计误差等多项不确定因素进行了评估,给出了反射率的修正方法和相应的不确定度分析结果.  相似文献   

Improved understanding of petroleum migration history in the Hongche fault zone,northwestern Junggar Basin (northwest China): Constrained by vein-calcite fluid inclusions and trace elements   总被引：1，自引：0，他引：1  

Jian Cao  Zhijun Jin  Wenxuan Hu  Yijie Zhang  Suping Yao  Xulong Wang  Yueqian Zhang  Yong Tang 《Marine and Petroleum Geology》2010

Calcite veins and cements occur widely in Carboniferous and Permian reservoirs of the Hongche fault zone, northwestern Junggar Basin in northwest China. The calcites were investigated by fluid inclusion and trace-element analyses, providing an improved understanding of the petroleum migration history. It is indicated that the Hongche fault behaved as a migration pathway before the Early Cretaceous, allowing two oil charges to migrate into the hanging-wall, fault-core and footwall reservoirs across the fault. Since the Late Cretaceous, the Hongche fault has been sealed. As a consequence, meteoric water flowed down only into the hanging-wall and fault-core reservoirs. The meteoric-water incursion is likely an important cause for degradation of reservoir oils. In contrast, the footwall reservoirs received gas charge (the third hydrocarbon event) following the Late Cretaceous. This helps explain the distribution of petroleum across the fault. This study provides an example of how a fault may evolve as pathway and seal over time, and how reservoir diagenetic minerals can provide clues to complex petroleum migration histories.  相似文献   

Experimental and computational validation and verification of the Stokes–Darcy and continuum pipe flow models for karst aquifers with dual porosity structure     

Xiaolong Hu  Xiaoming Wang  Max Gunzburger  Fei Hua  Yanzhao Cao 《水文研究》2012,26(13):2031-2040

In our previous study, we developed the Stokes–Darcy (SD) model was developed for flow in a karst aquifer with a conduit bedded in matrix, and the Beavers–Joseph (BJ) condition was used to describe the matrix–conduit interface. We also studied the mathematical well‐posedness of a coupled continuum pipe flow (CCPF) model as well as convergence rates of its finite element approximation. In this study, to compare the SD model with the CCPF model, we used numerical analyses to validate finite element discretisation methods for the two models. Using computational experiments, simulation codes implementing the finite element discretisations are then verified. Further model validation studies are based on the results of laboratory experiments. Comparing the results of computer simulations and experiments, we concluded that the SD model with the Beavers–Joseph interface condition is a valid model for conduit–matrix systems. On the other hand, the CCPF model with the value of the exchange parameter chosen within the range suggested in the literature perhaps does not result in good agreement with experimental observations. We then examined the sensitivity of the CCPF model with respect to the exchange parameter, concluding that, as has previously been noted, the model is highly sensitive for small values of the exchange parameter. However, for larger values, the model becomes less sensitive and, more important, also produces results that are in better agreement with experimental observations. This suggests that the CCPF model may also produce accurate simulation results, if one chooses larger values of the exchange parameter than those suggested in the literature. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献