附加系统参数平差法在导线网中的应用

本文探讨了附加系统参数平差法在带有测距系统误差的导线网中的应用，说明了当系统误差比较显著时．采用附加系统参数平差法的可行性、必要性及其优越性。     

江西省数字化雷达回波拼图技术方法的研究

介绍了江西省数字化雷达回波拼图的技术方法。该方法主要包括回波资料的预处理、拼图投影处理。它具有资料同一性、准确性好、方便灵活、适合业务使用等特点。     

高温环境下相对湿度测量误差及干湿球系数计算

对干湿球系数A与环境温度t的关系进行了研究。结果指出,A不仅与风速有关,也与环境温度有关,如果不考虑风速和环境温度,使用干湿球测湿法获得的测量结果没有使用价值。t〉40℃以后,随着t的升高,使用A的拟合公式计算得到的相对湿度值其误差愈来愈大,在相对湿度较低时情况更为明显。为此提出了在40℃〈t〈80℃范围内A的计算公式。经验证,使用此计算公式获得A值后再计算出相对湿度,其误差小于1．4％。     

Regional differences and determinants of built-up area expansion in China

Based on remote sensing data on land use provided by the Chinese Academy of Sciences and socio-economic data collected by the authors,this paper analyzes the trends and regional differences in built-up area(BUA) expansion in China from the late 1980s to 2000,and empirically estimates the major determinants of BUA expansion in different regions in 1996―2000.In 1989―2000,although China's overall BUA expansion accelerated,the trends differed significantly among regions.BUA expansion in the central and western regions accelerated significantly,but it slowed down considerably in the east-ern region.The estimation results from our econometric analysis reveal that BUA expansion in the eastern region reached a period when economic growth had no further significant impact on per capita BUA,the land utilization in this region has become more intensive with further expansion of the economy.In the central and western regions,the BUA has expanded remarkably due to the relatively more flexible land development policies and the relatively cheap land prices.Therefore,as the econ-omy continues to grow rapidly,policies relating to BUA expansion and cultivated land reductions may face more serious challenges in the central and western regions.     

褶皱构造中的地震——2017年三峡库区巴东M4.3地震序列成因讨论

2017年巴东M4.3地震序列为一发生在褶皱构造翼部的地震活动.地震精定位结果显示,整个地震序列呈NE向展布,震源深度较浅,M4.3和M4.1地震的震源深度分别为3.8 km和2.4 km.地震序列表现出NW浅、SE深的特征.震源机制解反演结果表明,两次较大地震的发震节面走向NEE,倾向SE,运动性质为走滑.震中区断裂构造分析发现,没有与发震节面吻合的断裂构造.结合地震定位结果和地质剖面分析,M4.3地震发生在三叠系岩溶及裂隙发育的厚层灰岩中,而M4.1地震及大多数小震活动则主要发生在巴东组红层（软弱滑脱层）中.地震发生时,三峡水库正处于低水位腾库容期间,库水卸荷使得库区原来由于荷载压实作用产生的压应力出现了局部回弹,进而引起部分裂隙的扩张,造成部分裂隙发育的岩体发生失稳滑动.此外,裂隙的扩张也为流体的渗透扩散提供了有利通道.流体渗透扩散一方面使得孔隙压力增大,有效应力降低;另一方面则使得软弱地层发生软化泥化,使得岩体发生顺层或切层的失稳滑动,造成了地震的发生.