探地雷达技术及其应用和发展

作者对近年来探地雷达的技术发展及新的应用研究进行了概括和总结。在详细分析探地雷达方法原理、系统结构的基础上,提出了改进探地雷达系统结构的思路;同时,针对探地雷达工作中的高噪声和地震数据处理技术移植的不适应性,提出了探地雷达地下界面高分辨率成像的新方法。     

长江三峡巴东县黄土坡前缘斜坡变形数据本构分析预测研究

应用数据本构分析方法,对三峡库区巴东县黄土坡前缘斜坡变形发展趋势进行了分析预测,阐明了数据本构分析预测对斜坡地质灾害的分析、防治意义     

A double-differenced cycle slip detection and repair method for GNSS CORS network

The difficulty to detect and repair cycle slip of carrier phase measurements is a key limit for continuously high accuracy of GNSS positioning and navigation services. We propose an automated cycle slip detection and repair method for data preprocessing of a CORS network. The method jointly uses double-differenced (DD) geometry-free (GF) combination and ionospheric-free observation corrected for the computed geometrical distance (IF-OMC) to estimate the cycle slips in dual-frequency observations. The DD GF combination, which is only affected by the ionospheric residual, can be used to detect cycle slips with high reliability except for special pairs such as (77, 60) on GPS L1/L2 frequencies. The detection principle of the IF-OMC observable is such that there is a large discontinuity related to the previous epoch when cycle slips occur at the present epoch. The disadvantages of these two combinations can be overcome employing the proposed detection method. The cycle slip pair (77, 60) has no effect on the GF combination, while a change of 14.65 m is derived from GPS L1/L2 observations using the IF-OMC algorithm. Using pre-determined station coordinates as precise values, we found that the accuracy of the DD IF-OMC combination was 18 mm for a 200-km CORS baseline. Therefore, cycle slips in dual-frequency observations can be correctly and uniquely determined using DD GF and IF-OMC equations. The proposed method was verified by adding simulated cycle slips in observations collected from the CORS network under a quiet ionosphere and shown to be effective. Moreover, the method was assessed with observations made during intense ionospheric activity, which generated extensive cycle slips. The results show that the algorithm can detect and repair all cycle slips apart from two exceptions relating to long data gaps.     

A two-layer model for studying 2D dissolved pollutant runoff over impermeable surfaces

Dissolved pollutants in stormwater are a main contributor to water pollution in urban environments. However, many existing transport models are semi-empirical and only consider one-dimensional flows, which limit their predictive capacity. Combining the shallow water and the advection–diffusion equations, a two-dimensional physically based model is developed for dissolved pollutant transport by adopting the concept of a ‘control layer’. A series of laboratory experiments has been conducted to validate the proposed model, taking into account the effects of buildings and intermittent rainfalls. The predictions are found to be in good agreement with experimental observations, which supports the assumption that the depth of the control layer is constant. Based on the validated model, a parametric study is conducted, focusing on the characteristics of the pollutant distribution and transport rate over the depth. The hyetograph, including the intensity, duration and intermittency, of rainfall event has a significant influence on the pollutant transport rates. The depth of the control layer, rainfall intensity, surface roughness and area length are dominant factors that affect the dissolved pollutant transport. Finally, several perspectives of the new pollutant transport model are discussed. This study contributes to an in-depth understanding of the dissolved pollutant transport processes on impermeable surfaces and urban stormwater management.     

页岩孔隙系统研究实验方法

基于页岩孔隙系统的特殊性,讨论了FESEM-QEMSCAN、FIB-FESEM、NANO-CT、氮气吸附法、小角中子散射等几种页岩孔隙系统研究方法的特点和适用范围。指出场发射扫描电镜以及与之结合的能谱和矿物定量评价系统(FESEM-QEMSCAN)是研究页岩纳米级孔隙类型、大小、形态以及矿物分布的基础手段;聚焦离子束扫描电镜、微纳米CT可刻画页岩孔隙系统在三维空间的展布特征,利用获得的三维数据体进行数值模拟,可进一步计算孔隙度、渗透率等物性参数;氮气吸附法可对小于100nm的极微孔隙的孔径、形态进行求算;小角中子散射则可利用孔隙中存在的气体分子,获得孔隙系统连通性等重要参数。最后从页岩岩石组构的角度,探讨了页岩孔隙控制因素,指出有机质含量与成熟度,黏土矿物类型、含量,碎屑颗粒的含量以及成岩强度是影响页岩孔隙系统的主要因素。     

密云水库年及汛期径流量年际变化特征的分析

利用定级分类，累积，谱分析等统计方法，分析了密云水库１９１９－１９８９年全年及汛期径流量年际变化的特征，发现密云水库全年及汛期径流量的年际变化具有持续性，周期性，多数年份偏枯等特性。     

防雷检测业务系统数据库的实现

利用桌面数据库创建防雷检测业务系统数据库,可方便地对防雷检测业务、防雷检测信息进行追加、浏览、修改和查询等操作,查询结果可以打印或者生成文本文件,还可以利用OLE技术生成word文档、Excel文档保存.数据库经过加密,用户必须登陆才能操作数据库,保存用户使用信息,包括登陆时间、进行的操作等.系统具有完善的备份功能,可以保证数据库在误删除的情况下被安全恢复;具有较好的可移植性,可以应用于具有防雷检测业务的气象台站.     

Thermal and tectonic evolution of the southern Alps (northern Italy) rifting: Coupled organic matter maturity analysis and thermokinematic modeling

The Pearl River Mouth Basin (PRMB) is one of the most petroliferous basins on the northern margin of the South China Sea. Knowledge of the thermal history of the PRMB is significant for understanding its tectonic evolution and for unraveling its poorly studied source-rock maturation history. Our investigations in this study are based on apatite fission-track (AFT) thermochronology analysis of 12 cutting samples from 4 boreholes. Both AFT ages and length data suggested that the PRMB has experienced quite complicated thermal evolution. Thermal history modeling results unraveled four successive events of heating separated by three stages of cooling since the early Middle Eocene. The cooling events occurred approximately in the Late Eocene, early Oligocene, and the Late Miocene, possibly attributed to the Zhuqiong II Event, Nanhai Event, and Dongsha Event, respectively. The erosion amount during the first cooling stage is roughly estimated to be about 455–712 m, with an erosion rate of 0.08–0.12 mm/a. The second erosion-driven cooling is stronger than the first one, with an erosion amount of about 747–814 m and an erosion rate between about 0.13–0.21 mm/a. The erosion amount calculated related to the third cooling event varies from 800 m to 3419 m, which is speculative due to the possible influence of the magmatic activity.     

中国与基性—超基性岩有关的Cu－Ni（Pt）矿床成矿系列类型

中国与基性—超基性岩有关的Ｃｕ－Ｎｉ（Ｐｔ）矿床，主要形成于以前寒武系为基底的大陆裂谷，部分形成于增生褶皱带中显生宙地层为基底的裂陷槽环境。根据形成时代、当时所在的构造环境单元及成矿岩浆系列，划分为９个矿床成矿系列和８个矿床成矿亚系列。成矿时代以元古代、晚古生代为主。现今，矿床主要分布于地台边缘，造山带中也有产出，但不代表其当时形成的地质背景。成矿物质来源为上地幔，原始岩浆以上地幔部分熔融的高ＭｇＯ拉斑玄武岩（拉斑橄榄玄武岩）岩浆系列为特征，也有钙碱性岩浆（喀拉通克）和科马提岩岩浆系列（桂北）。地壳物质混染比较普遍。矿床成因类型主要为岩浆熔离型，且以硅酸盐岩浆上侵前的深部熔离作用为主。还有热液成因类型（煎茶岭）。矿床成矿系列的时空分布与中国大陆的构造演化密切相关     

分辨率对区域气候极端事件模拟的影响

利用NCAR MM5V3对1999年6月长江流域的极端异常降水事件进行了模拟, 主要研究不同水平和垂直分辨率对极端区域气候事件模拟的影响.数值模拟试验表明:模式能够模拟出极端强降水的主要分布特征;水平分辨率的提高降低了模式模拟的强降水偏差,对逐日降水变化的模拟更加合理,而垂直分辨率的提高基本上也都减小了模拟的强降水过程的偏差,改善对强降水的模拟能力;模式水平、垂直分辨率的提高在一定程度上增强了对强降水过程的模拟能力.水平分辨率的提高能够改善模式对海平面气压的模拟,而垂直分辨率的提高可以改善模式模拟的地面气温和低层环流.分辨率对中层大气环流的影响不是很敏感.不同积云对流参数化方案模拟的对流降水比率随水平分辨率的变化是不同的,Grell方案对流降水比例随分辨率的提高而增加,而Kain-Fritsch方案的结果相反.