山区阶梯式河道水流阻力研究

山区阶梯式河道是自然界来水来沙和山区大比降河床相互作用所形成的,其水力特性、河道阻力较为复杂。为了深入研究其阻力机理,从河床结构阻水的角度提出阶梯式结构糙率尺度的概念,得到了适用于阶梯式河道跌落水流的形体阻力系数表达式,并由不同来源的阻力分量构成了新的山区阶梯式河道水流总阻力系数公式。新公式结果表明,通过不同类型河段的野外试验数据,表面泥沙、阶梯形状以及漂石产生的阻力系数分量之和与试验测量总阻力系数数据的误差较小。随着雷诺数和阶梯单元尺寸的增加,河床表面的泥沙肤面阻力系数基本不变,阶梯式结构形成的跌落水流过渡到滑行水流,阶梯形体阻力系数逐渐变小,而较大粒径松散漂石产生的水流阻力系数只随着雷诺数的增大而减小。     

伟晶岩绿柱石矿物学及其通道水氢同位素研究进展

自然界绿柱石存在三个类质同象系列,即“八面体”绿柱石（ｃ／ａ＝０．９９１￣０．９９６）,“正常”绿柱石和“四面体”绿柱石。绿柱石矿物精细结构研究表明,二价离子置换八面体中Ａｌ,Ｌｉ置换四面体中Ｂｅ,而碱离子被绿柱石通道所容纳,用于补偿低价阳离子置换Ａｌ八面体和Ｂｅ四面体引起的电价不足。伟晶岩绿柱石通常含有〉１．６ｗｔ％的通道水,而包裹体中流体仅为０．１５ｗｔ％左右。室温下绿柱石通道中存在１型和Ⅱ     

IDENTIFICATION AND ANALYSIS OF NATURAL CHANNEL NETWORKS FROM DIGITAL ELEVATION MODELS

The identification and analysis of natural channel networks from digital elevation models are discussed from the point of view of their environmental applications. An interactive, graphical software package that implements some of the most widely used techniques for the automatic recognition of channel networks and for the computation of some useful geomorphologic indices and functions is presented.     

基于数据传输特性的卫星广播通道参数优化方法与应用

中国气象局卫星广播系统（CMACast）是全球对地观测广播系统（GEONETCast）框架下三大对地广播系统之一,在世界气象组织信息系统（WIS）和综合卫星数据分发服务系统(IGDDS)框架下,承担亚太地区气象数据广播分发的职责。随着气象业务的发展,广播系统数据量由180 GB/天增长至460 GB/天,在广播带宽资源有限而广播数据种类和大小各异的情况下,系统管理员越来越难以通过经验对广播通道参数调整以保持广播系统播发效率,造成部分通道数据播发时效下降严重,不能满足业务时效要求。通过对不同气象数据传输特性的定量分析,获得各类数据的精细化数据传输样本,在此基础上对各类数据广播通道参数进行科学、定量的计算和优化,使数据播发时效明显提升,应用到实际广播业务中效果明显。     

Sequestration of CO2 in geological media: Criteria and approach for site selection in response to climate change

The well-developed coal electricity generation and coal chemical industries have led to huge carbon dioxide (CO₂) emissions in the northeastern Ordos Basin. The geological storage of CO₂ in saline aquifers is an effective backup way to achieve carbon neutrality. In this case, the potential of saline aquifers for CO₂ storage serves as a critical basis for subsequent geological storage project. This study calculated the technical control capacities of CO₂ of the saline aquifers in the fifth member of the Shiqianfeng Formation (the Qian-5 member) based on the statistical analysis of the logging and the drilling and core data from more than 200 wells in the northeastern Ordos Basin, as well as the sedimentary facies, formation lithology, and saline aquifer development patterns of the Qian-5 member. The results show that (1) the reservoirs of saline aquifers in the Qian-5 member, which comprise distributary channel sand bodies of deltaic plains, feature low porosities and permeabilities; (2) The study area hosts three NNE-directed saline aquifer zones, where saline aquifers generally have a single-layer thickness of 3‒8 m and a cumulative thickness of 8‒24 m; (3) The saline aquifers of the Qian-5 member have a total technical control capacity of CO₂ of 119.25 × 10⁶ t. With the largest scale and the highest technical control capacity (accounting for 61% of the total technical control capacity), the Jinjie-Yulin saline aquifer zone is an important prospect area for the geological storage of CO₂ in the saline aquifers of the Qian-5 member in the study area.     

渭河下游河道调整过程中的复杂响应现象

应用系统复杂响应的原理研究三门峡水库上游渭河河道调整过程,表明上游河道河床形态对基面上升所作出的响应是复杂的,弯曲系数的变化为先减小而后增大,宽深比的变化是先增大后减小,比降由先减小而后增大,最后均趋于稳定.     

珠江河网分形机理研究

以不同时期珠江网河历史地图及遥感影像为基础,进行了河网分形计算,并从河道发育、人为活动等多个角度分析了珠江网河分形机理。在发育过程中,1883-2001年间河网分维值逐渐减小;在空间上,正干水道中潮道分维值大于分汊河道。分析认为,人为活动是导致珠江网河分形变化的主要因素:联围筑闸消灭横向支汊、口门整治及河道固化减小了河道冲决的几率、河道挖沙引起的水沙分流比变化改变了河道冲淤特性。