Chemical Evolution of Blue Compact Galaxies

Based on a sample of 72 Blue Compact Galaxies (BCGs) observed with the 2.16m telescope of the National Astronomical Observatories, Chinese Academy of Sciences (NAOC) and about 4000 strong emission line galaxies from the Sloan Digital Sky Survey, we analyzed their chemical evolution history using the revised chemical evolution model of Larsen et al. Our sample covers a much larger metallicity range (7.2 < 12 log(O/H) < 9.0). We found that, in order to reproduce the observed abundance pattern and gas fraction over the whole metallicity range, a relatively continuous star formation history is needed for high metallicity galaxies, while assuming a series of instantaneous bursts with long quiescent periods (some Gyrs) for low metallicity galaxies. Model calculations also show that only the closed-box model is capable of reproducing the observational data over the whole metallicity range. Models that consider the ordinary winds and/or inflow can only fit the observations in the low metallicity range, and a model with enriched wind cannot fit the data in the whole metallicity range. This implies that the current adopted simple wind and inflow models are not applicable to massive galaxies, where the underlying physics of galactic winds or inflow could be more complicated.     

TJ-Ⅱ型钻孔体应变仪数字化观测资料分析

对位于山东省不同地理、构造条件的4个TJ－Ⅱ型钻孔体应变仪数字化观测资料进行了分析，结果表明：4个台的体应变资料不同程度地受降雨、地下水位、气压、温度的影响，其完整性、稳定性和可靠性不同，记录地震波的能力也存在差异。     

Comparative Analysis of Seismic Response of Pile-Soil-Structure Interaction System

The study on the earthquake-resistant performance of a pile-soil-structure interaction system is a relatively complicated and primarily important issue in civil engineering practice. In this paper, a computational model and computation procedures for pile-supported structures, which can duly consider the pile-soil interaction effect, arc established by the finite clement method. Numerical implementation is made in the time domain. A simplified approximation for the seismic response analysis of pile-soil-structure systems is briefly presented. Then a comparative study is performed for an engineering example with numerical results computed respectively by the finite clement method and the simplified method. Through comparative analysis, it is shown that the results obtained by the simplified method well agree with those achieved by the finite element method. The numerical results and findings will offer instructive guidelines for earthquake-resistant analysis and design of pile-supported structures.     

遥感技术在断裂研究中的应用——以张家口—蓬莱断裂带为例

张家口一蓬莱断裂带是一条北西西向活动断裂带。本文选取ETM+光学影像和SRTM高程影像作为主要数据源,结合研究区已有地质资料研究发现该带断裂构造的北西西向线性特征明显。从水系分布和错断地形等地貌标志判断,该断裂具有左阶组合样式和左行走滑活动特征。据遥感影像综合特征,可将该带分为张家口段、延庆-怀来段和北京一天津段,影像特征分段性显著,并与断裂带的分段性一致。研究结果表明,张家口-蓬莱断裂具有左行走滑的运动学特征,限制或错断北北东或北东向断裂,并且控制该区域的左阶雁列式第四纪盆地群和第四纪冲洪积物的分布。该断裂带各段对不同规模的水系分布和形态影响比较大,且北京-天津地区的华北平原段断裂对第四纪冲洪积扇和沿海地区的贝壳堤的形态和分布有一定的控制作用。地球物理深部数据和野外地质考察资料也证实了遥感解泽的结果,证明遥感技术在探查断裂构造空间展布和活动性鉴定中有着广泛的应用前景。     

中国湿地保护区与湿地公园空间分布差异

以等降水线、地表径流和干湿度地区为参考因子,讨论中国湿地保护区和湿地公园的空间分布差异。利用Arc GIS软件,分析中国湿地保护区和湿地公园密度分布相关性,计算两者重叠和互补性;通过基尼系数和综合密度等指数,在八大经济区域尺度上,比较湿地自然保护区和湿地公园空间分布的均衡程度。在年降水量为600~800 mm的区域,湿地保护区和湿地公园的数量最多;湿地保护区和湿地公园都趋向河流分布,湿地保护区距离河流更近;半湿润区湿地保护区数量和面积都最大,湿地公园面积都很小。湿地保护区和湿地公园平均核密度为0.49×10-4个/km2和0.45×10-4个/km2,二者的分布密度不相关(r=0.31)。湿地保护区和湿地公园空间的最邻近距离指数都小于1,呈现聚集分布。在区域尺度上,湿地保护区和湿地公园基尼系数分别为0.93和0.98,各经济区域之间综合密度分布差异较大。湿地保护区主要分布在有重要湿地资源的中国东北、东南和西南等地区,在湿地保护生态系统中发挥主要作用;而湿地公园多分布在经济发展较快的北部沿海和东部沿海地区,更贴近人类生活,有效补充了湿地保护区的不足。     

基于IMS的气象信息传输智能语音通知系统设计与实现

目前气象信息传输监视工作主要依靠人工拨号辅助发送短信的方式将异常信息通知到台站,该方式的特点是对多个台站串行通知,及时性不足。介绍一种基于IMS的智能语音通知系统的设计与实现过程,包括系统硬件架构、软件系统设计。与基于语音板卡的方案相比,硬件架构以多媒体交换机为核心,以移动IMS为支撑,实现了TTS 4路并行转换、30路语音通道并发外呼;软件系统采用B/S和C/S相结合的方式来设计：C/S负责气象通信业务中异常信息的采集和语音通知的发送,B/S负责语音信息的显示、统计和分析。应用结果表明,该系统运行稳定可靠,体现了智能语音告警通知的优势。     

The mechanism of deep material transport and seismogenic environment of the Xiaojiang fault system revealed by 3-D magnetotelluric study

Science China Earth Sciences - The Xiaojiang fault system (XJFS), located to the southeast of the Tibetan Plateau, has a complicated tectonic history and is an ideal location to study the Tibetan...     

Scenario simulation of the geohazard dynamic process of large-scale landslides: a case study of the Xiaomojiu landslide along the Jinsha River

Natural Hazards - Large-scale landslides often cause severe damage due to their long run-out distances and having disaster chain effects. Scenario simulation has been adopted in the current work in...     

Experimental Study on Rock Failure Characteristics of Ejective Rock Burst Based on Energy Compensation

Geotechnical and Geological Engineering - Rock burst is a typical type of dynamic geological disaster in the process of underground engineering excavation under high in-situ stress. Based on the...     

Influence of hydrate exploitation on stability of submarine slopes

Urban pluvial flash floods have become a matter of widespread concern, as they severely impact people’s lives in urban areas. Hydrological and hydraulic models have been widely used for urban flood management and urban planning. Traditionally, to reduce the complexity of urban flood modelling and simulations, simplification or generalization methods have been used; for example, some models focus on the simulation of overland water flow, and some models focus on the simulation of the water flow in sewer systems. However, the water flow of urban floods includes both overland flow and sewer system flow. The overland flow processes are impacted by many different geographical features in what is an extremely spatially heterogeneous environment. Therefore, this article is based on two widely used models (SWMM and ANUGA) that are coupled to develop a bi-directional method of simulating water flow processes in urban areas. The open source overland flow model uses the unstructured triangular as the spatial discretization scheme. The unstructured triangular-based hydraulic model can be better used to capture the spatial heterogeneity of the urban surfaces. So, the unstructured triangular-based model is an essential condition for heterogeneous feature-based urban flood simulation. The experiments indicate that the proposed coupled model in this article can accurately depict surface waterlogged areas and that the heterogeneous feature-based urban flood model can be used to determine different types of urban flow processes.