基于主体功能区划的广西沿海地区发展     

曾令锋  黎忠  吕曼秋  康乐 《热带地理》2008,28(5)

运用区域主体功能区划理论,对广西沿海地区的发展进行了分析.研究表明,广西经济布局初具"T"字型空间结构,但沿海地区空间结构还存在不少无序现象,海洋经济与人才的观念比较薄弱.应根据区域主体功能区划理论,在确立海洋经济为区域经济主体的基础上,进一步明确钦州、北海和防城港三市区域功能,加快构建相应中心城市集聚区,以旅游和边贸为切入点,加强与东盟、泛珠三角和西南等经济区的联系,不断提高区域经济实力.  相似文献   

顺层岩质边坡地震动力响应研究   总被引：1，自引：0，他引：1  

言志信  高乐  彭宁波  任志华  郭斌 《岩土力学》2012,33(Z2):85-090

地震作用下边坡的动力响应研究是边坡动力稳定分析的基础,利用FLAC3D有限差分软件建立一个顺层岩质边坡动力数值模拟模型,对其在竖向和水平向地震耦合作用下的动力响应全过程进行研究。研究表明,地震竖向和水平向耦合作用模拟比简单的模拟水平向振动更加接近实际情况,对岩土体的破坏更大;顺层岩质边坡在耦合地震作用下存在垂直放大和临空面放大作用;坡面水平向和竖向加速度均随高程增加呈增大趋势,在结构面处增大特别明显;竖向地震波产生的水平与竖向拉裂是触发斜坡体产生初期崩滑破坏的主控因素;边坡动力响应特征值的放大效应表明,其放大系数值从大到小依次是：竖向加速度＞水平加速度＞竖向速度＞水平速度;耦合地震波作用下,随着av /aH的增大,坡面监测各点横向位移基本呈增大趋势,说明竖向地震作用起了重要的破坏作用。  相似文献   

Crossed molecular beam study of gas phase reactions relevant to the chemistry of planetary atmospheres: The case of C₂+C₂H₂     

Francesca Leonori  Enrico Segoloni  Sébastien D. Le Picard 《Planetary and Space Science》2008,56(12):1658-1673

The reaction between dicarbon (C₂) and acetylene was recently suggested as a possible competitive reaction in the atmospheres of Titan, Saturn and Uranus by rate constant measurements at very low temperatures [see Canosa, A., Páramo, A., Le Picard, S.D., Sims, I.R., 2007. An experimental study of the reaction kinetics of C₂(X¹Σ_g⁺) with hydrocarbons (CH₄, C₂H₂, C₂H₄, C₂H₆ and C₃H₈) over the temperature range 24-300 K: implications for the atmospheres of Titan and the Giant Planets. Icarus 187, 558-568]. We have investigated the reaction of the two low lying electron states of C₂ and acetylene by the crossed molecular beam (CMB) technique with mass spectrometric detection. C₄H, already identified as a primary product in previous CMB experiments, is confirmed as such, even though the mechanism of formation is inferred to be partly different with respect to the previous study. An experimental setup has been devised to characterize the internal population of C₂ and refine the interpretation of the scattering results. The implications for the modelling of the atmospheres of Giant Planets and Titan, as well as cometary comae and the interstellar medium, are discussed.  相似文献   

Petrology and mineralogy of the angrite Northwest Africa 1670     

A. JAMBON  O. BOUDOUMA  M. FONTEILLES  C. Le GUILLOU  D. BADIA  J.‐A. BARRAT 《Meteoritics & planetary science》2008,43(11):1783-1795

Abstract— Northwest Africa (NWA) 1670, contains olivines of up to 5 mm in size representing about 30% of the studied section. With subordinate clinopyroxene and chrome‐spinel microphenocrysts (0.2‐0.5 mm), they represent a xenocrystic association. Phenocrysts are surrounded by a groundmass, predominantly comprising bundles of plagioclase and clinopyroxene (typically 20 × 200 μm crystals). Olivine and kirschsteinite are present in the groundmass in lesser amounts. The olivine xenocrysts (Fo90) are significantly fractured and show mosaicism for their major part, the remaining showing faint undulatory extinction. They are surrounded with a rim of 100–200 μm zoned down to Fo80 and overgrown with serrated olivine, Fo80 to Fo60 (about 100 μm). Olivine in the groundmass is zoned from Mg# 0.55 to 0.15; its CaO content ranges 2.0 to 8.4%. Subcalcic kirschsteinite is zoned from Mg# 0.13 to 0.03, CaO increasing from 15.8 to 21.3%. Pyroxenes xenocrysts (Mg# = 0.77) are superseded in the groundmass by less magnesian pyroxenes, Mg# 0.61 to 0.17, with an average FeO/ MnO of 98. Their compositions range from En₃₀ Fs₂₂ Wo₂₇ Al‐Ts₂₈ Ti‐Ts₂ to En₂ Fs₃₇ Wo₂₂ Al‐Ts₄₀ Ti‐Ts₁. Anorthite microcrysts (An99‐100) are restricted to the groundmass. Accessories are pyrrhotite, kamacite, Ca‐phosphate, titanomagnetite, hercynite and Ca‐carbonate. The bulk chemical composition confirms that NWA 1670 corresponds to a normal angrite melt that incorporated olivine. High Mg olivine xenocrysts and the associated mineralogy are typical of angrites. We suggest that it is an impact melt with relict phenocrysts. The strong silica undersaturation, the presence of Fo90 olivine xenocrysts and carbonate support their derivation as melilite‐like melts in the presence of carbonate.  相似文献   

Accounting for end-user preferences in earthquake early warning systems   总被引：1，自引：1，他引：0  

Thomas Le Guenan  Farid Smai  Annick Loschetter  Samuel Auclair  Daniel Monfort  Nicolas Taillefer  John Douglas 《Bulletin of Earthquake Engineering》2016,14(1):297-319

  相似文献   

Earthquake early warning and operational earthquake forecasting as real-time hazard information to mitigate seismic risk at nuclear facilities     

Carlo?CauzziEmail author  Yannik?Behr  Thomas?Le?Guenan  John?Douglas  Samuel?Auclair  Jochen?Woessner  John?Clinton  Stefan?Wiemer 《Bulletin of Earthquake Engineering》2016,14(9):2495-2512

Based on our experience in the project REAKT, we present a methodological framework to evaluate the potential benefits and costs of using earthquake early warning (EEW) and operational earthquake forecasting (OEF) for real-time mitigation of seismic risk at nuclear facilities. We focus on evaluating the reliability, significance and usefulness of the aforementioned real-time risk-mitigation tools and on the communication of real-time earthquake information to end-users. We find that EEW and OEF have significant potential for the reduction of seismic risk at nuclear plants, although much scientific research and testing is still necessary to optimise their operation for these sensitive and highly-regulated facilities. While our test bed was Switzerland, the methodology presented here is of general interest to the community of EEW researchers and end-users and its scope is significantly beyond its specific application within REAKT.  相似文献   

广西平南某矿区岩溶地下水连通试验研究   总被引：2，自引：2，他引：0  

庾乐  王礼恒  王举平 《中国岩溶》2014,33(1):31-36

广西平南某矿区在人工疏水过程中地下水位持续下降,形成以采区为降落漏斗、周边地下水向采区径流排泄的地下水流场。位于矿区东侧的秦川河成为危及矿区施工安全的最大隐患。为了查明矿区岩溶地下水径流途径、径流特征,进而了解矿区采矿排水的主要来源及周边地表河的影响,在矿区周围进行了地下水连通试验。试验结果表明:矿区岩溶含水介质渗透性差异较大,含水层各向异性明显;矿区北部、东南部存在连通性较好的地下水径流带,北部流速为0.3 ~ 20 m/h,东南部流速为3.72 ~ 98 m/h;矿区南部、西南部与周边地下水连通性较差,与矿区以南的浔江存在地下分水岭;矿区东部一采区矿坑排水主要来自东侧秦川河渗漏补给及北部地下水侧向径流补给,矿区西部二采区矿坑排水补给来源为北部地下水侧向径流及大气降水。因此,采矿疏水过程中应及时掌握秦川河水位变化情况,采取帷幕等有效手段对水害进行治理,以确保生产安全。   相似文献   

中国城市休闲商业街区研究进展   总被引：2，自引：0，他引：2  

朱鹤  刘家明  李玏  陶慧 《地理科学进展》2014,33(11):1474-1485

随着人们闲暇时间和收入的增长,休闲旅游不断发展,而城市休闲商业街区(RBD)作为城市旅游的重要游憩空间,受到普遍关注.城市RBD是传统商业与旅游业的融合,对于城市旅游业的发展、经济转型、城市形象的提升具有重要意义.本文以知网检索到的与RBD相关的246 篇文献为基础,以论文年发表数量和增长率作为主要的评价依据,首先分析国内RBD研究进程,将其分为起步发展、快速发展、巩固发展3 个阶段,从研究主题、使用方法、研究层次等角度对每个阶段特征进行分析.其次,分析文献内容,对RBD的相关研究方向进行划分,共分为12 大类,并从RBD的相关概念与定义、RBD的特征功能与分类、形成机制与过程、空间结构与布局、RBD发展对城市的影响、RBD的旅游形象与游客体验感知、RBD的开发与规划7 个方面对国内RBD研究现状进行了综述.最后对RBD的研究中存在的问题进行总结,其中,概念定义的统一、深化案例研究、细化研究方向、提炼理论层次、应用定量化研究方法、建立评价指标体系等都是今后的研究中应加强的环节,并对今后的研究方向和重点进行展望.  相似文献   

地震应急卫星通信网路由异常分析     

杨乐  谭颖  曾薇  章静 《地震地磁观测与研究》2014,(1):250-252

地震应急卫星通信网一直存在路由异常的问题,时常造成卫星站点通信不畅。通过对网络拓扑结构进行分析,总结造成路由异常的原因。通过列举实例,提出以通过设置静态路由的方式,来解决目前网络中存在的路由异常问题。  相似文献   

OSPF在地震应急卫星通信网中的应用研究     

曾薇  杨乐 《震灾防御技术》2014,9(2):304-309

在地震灾害发生后,地震应急卫星通信网为地震救援提供高效可靠的音视频以及数据传输信道。由于地震灾害的突发性和不可预见性,地震应急卫星通信网在满足业务传输需求的同时需要实现灵活组网。OSPF(Open Shortest Path First,优先开放最短路由协议)较小的网络开销以及兼具灵活的组网方式,对于带宽资源有限的卫星通信系统来说无疑是相当具有优势的。本文着重研究了OSPF在地震应急卫星通信网中的具体应用。  相似文献