华南某矿区磁铁矿的谱学研究     

杜金龄  邓璟  曾令初  余正方  范家师  吴杰陶  郑裕芳 《地球科学》1986,(2)

从~（57）Fe和~（119）Sn无反冲共振吸收谱分析,配合x射线衍射分析等方法,获知华南某铁矿-多金属矿区,两种铁矿石中磁铁矿的组份。从穆斯堡尔谱峰面积法,推算出非正分的磁铁矿晶体结构式,并由此算出其中Fe~（2+）和Fe~（3+）的含量比。综合矿石产状及铁的氧化态分析,获得不同铁矿石的成因信息。  相似文献   

光束抖动频谱遥感大气湍流外尺度的理论与实验     

宋正方  李玉杰 《安徽地质》1997,(1)

本文在微扰理论的基础上导出了高斯光束抖动归一化频谱的普遍表达式和准直光束、球面波光束在均匀光路条件下的分析表达式。计算表明这些频谱中存在一个与湍流外尺度、横截风速有确定关系的峰值频率。我们根据这个特征利用大气相干长度测量仪进行了湍流外尺度的遥感实验，与此同时用五台三杯风速计测量了光路中的平均风速。实验结果指出，离地面８ｍ高度上的湍流外尺度在２．６－７．０ｍ之间变化，平均值为４．９ｍ  相似文献   

Climate change in Northeast China between 1849 and 2008     

Xiaodong Wang  Huiqing Liu  Weihong Fan  Jiawei Xu  Zhengfang Wu  Weihua Dong 《Theoretical and Applied Climatology》2016,126(3-4):765-773

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秦山核电站邻近水域溶解氧和化学耗氧量的分布特征     

龚敏  王正方 《海洋学研究》1991,9(2):27-33

本文运用秦山核电站邻近水域零点生态调查四个航次中(春、夏、秋、冬)溶解氧和化学耗氧量两要素的检测数据,着重描述溶解氧和化学耗氧量的分布特征,并分析了环境因子对其变化的影响。  相似文献   

遥感影像并行服务系统设计与实现     

周郑芳  易磊  王惠  卢志渊  陈征 《测绘科学技术学报》2015,(1):42-46,51

实现海量遥感影像快速处理的重要基础是高速影像数据服务。基于影像瓦片模型、分布式并行存储体系结构,设计和实现遥感影像并行服务系统——瓦片服务系统,用于快速存储和访问以瓦片方式组织的遥感影像,为高速影像处理、实景城市等提供高吞吐数据服务。实验结果表明:瓦片服务系统具有快速存储和访问海量遥感影像的能力,在高速影像处理与影像服务等领域具有广阔应用前景。  相似文献   

Influence of fault steps on rupture termination of strike-slip earthquake faults     

Zhengfang Li  Bengang Zhou 《Journal of Seismology》2018,22(2):487-498

A statistical analysis was completed on the rupture data of 29 historical strike-slip earthquakes across the world. The purpose of this study is to examine the effects of fault steps on the rupture termination of these events. The results show good correlations between the type and length of steps with the seismic rupture and a poor correlation between the step number and seismic rupture. For different magnitude intervals, the smallest widths of the fault steps (Lt) that can terminate the rupture propagation are variable: Lt?=?3 km for Ms 6.5~6.9, Lt?=?4 km for Ms 7.0~7.5, Lt?=?6 km for Ms 7.5~8.0, and Lt?=?8 km for Ms 8.0~8.5. The dilational fault step is easier to rupture through than the compression fault step. The smallest widths of the fault step for the rupture arrest can be used as an indicator to judge the scale of the rupture termination of seismic faults. This is helpful for research on fault segmentation, as well as estimating the magnitude of potential earthquakes, and is thus of significance for the assessment of seismic risks.  相似文献   

1960～2017年华北地区气候生长季变化特征及成因分析   总被引：1，自引：1，他引：0  

董满宇  李洁敏  王磊鑫  刘佩佩  江源  吴正方 《地理科学》2019,39(12):1990-2000

基于华北地区1960~2017年逐日气温数据,运用Mann-Kendall非参数检验、Morlet小波分析和R/S分析等方法,分析了华北地区气候生长季指标生长季开始（GSS）、生长季结束（GSE）、生长季长度（GSL）、生长季内≥10℃活动积温（AT10）及其对应的天数（DT10）的时空变化特征及其影响因素。结果表明:① 华北地区GSS呈显著的提前趋势,变化速率为-2.43 d/10a,GSL呈现出明显延长,AT10和DT10表现为显著增加趋势,变化速率分别为2.95 d/10 a、67.14℃/10a和2.31 d/10a,GSE变化趋势不明显。近60 a来华北地区GSL的延长主要归因于GSS的明显提前。② 生长季指标变化趋势在空间上存在明显差异,其中GSS与GSL,AT10与DT10变化趋势的空间分布格局较为相似。③ 生长季指标普遍在20世纪90年代中后期发生了明显的突变,GSS、GSE和GSL的突变年份为1994~1995年,AT10和DT10的突变年份为1997~1998年。④ 近60 a来华北地区生长季指标变化存在着2~3 a、5~6 a的主周期。生长季指标Hurst指数都大于0.7,表现为较强的持续性,其过去变化趋势将在未来继续延续。⑤ 北大西洋年代际振荡指数（AMO）是影响近60 a来华北地区生长季指标（GSS、GSE与AT10）变化的主要大气环流因子。  相似文献   

Urban flooding in China: main causes and policy recommendations          下载免费PDF全文

Zheng Zheng  Junqi Gao  Zhen Ma  Zhengfang Wang  Xiaoying Yang  Xingzhang Luo  Thierry Jacquet  Guangtao Fu 《水文研究》2016,30(7):1149-1152

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Interdecadal changes of vegetation transition zones and their responses to climate in Northeast China   总被引：1，自引：1，他引：0  

Haibo Du  Zhengfang Wu  Ming Li 《Theoretical and Applied Climatology》2011,106(1-2):179-188

According to the concept of ecoclimatic factor??s guarantee rate, this study purposes to quantitatively analyze the interdecadal changes of the four major vegetation transition zones in Northeast China based on the warmth index first developed by Kira and the humidity index put forward by Xu during the period 1961?C2007. On this basis, the responses of the interdecadal changes of vegetation transition zones to climate were analyzed. The results indicated that latitudinal vegetation transition zones had been moving laggingly to higher latitude (shifting upwards in altitude) and that longitudinal vegetation transition zones had been shifting slowly toward humid area in the whole sequence, whereas the shifts were fluctuant in stages. The changes of vegetation transition zones of Northeast China expressed in distribution and bandwidth responded to climate change, not only in the whole sequence but also in stages.  相似文献   

Extracting vegetation phenology metrics in Changbai Mountains using an improved logistic model   总被引：1，自引：0，他引：1  

Ming Li  Zhengfang Wu  Lijie Qin  Xiangjun Meng 《中国地理科学(英文版)》2011,21(3):304-311

Remotely sensing images are now available for monitoring vegetation dynamics over large areas.In this paper,an improved logistic model that combines double logistic model and global function was developed.Using this model with SPOT/NDVI data,three key vegetation phenology metrics,the start of growing season (SOS),the end of growing season (EOS) and the length of growing season (LOS),were extracted and mapped in the Changbai Mountains,and the relationship between the key phenology metrics and elevation were ...  相似文献