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201.
黏弹性阻尼器是一种典型的被动控制装置,它可以通过黏弹性材料的剪切滞回耗能起到提高结构阻尼和减小结构地震或风振响应的作用.自主研发了损失系数不小于0.5的黏弹性材料,并基于此材料研发了新型国产黏弹性阻尼器.通过对黏弹性阻尼器足尺试件进行不同应变幅值、加载频率工况下的基本力学性能试验、以及低周疲劳性能试验,研究了不同工况下...  相似文献   
202.
飞地增长是指新增建设用地与原有建设用地相离的扩张方式,是快速城市化的中国城市发展中普遍存在的现象.本文以多源地理大数据以及土地利用数据为基础,在斑块尺度单元,测度中国三大城市群在1995—2015年间新增飞地斑块空间活力水平.研究表明:长三角地区飞地斑块数量最多、总面积最大,而斑块空间活力最低;珠三角地区的飞地斑块数量...  相似文献   
203.
以自然资源价值理论为指导,构建以使用价值和生态价值为基础的自然岸线资源二元价值结构。结果表明:通过建立自然岸线资源物质量与价值量核算方法,得出大连市自然岸线资源物质总量为766.6 km,全市自然保有率为46.9%。到“十四五”末,大连市海岸线资源价值总量约1 792.88亿元,自然资源岸线价值组成中生态价值占主导地位,价值量占比为99.8%。该核算方法实现了自然岸线资源生态价值的内部化过程,解决了岸线资源的价值以使用价值为主、对生态价值的忽视或考虑不足、导致整体价值被低估的核心问题。过度的资源开发是造成自然岸线资源稀缺的原因,加之资源保护与开发的高质量发展模式,自然岸线资源价值将不断攀高。自然岸线资源价值也将成为沿海地区核心价值的重要组成部分。  相似文献   
204.
The Carnian Pluvial Episode (CPE) fingerprints global environmental perturbations and biological extinction on land and oceans and is potentially linked to the Wrangellia Large Igneous Province (LIP). However, the correlation between terrestrial environmental changes and Wrangellia volcanism in the Ordos Basin during the CPE remains poorly understood. Records of negative carbon isotopic excursions (NCIEs), mercury (Hg), Hg/TOC, and Hg enrichment factor (HgEF) from oil shales in a large-scale terrestrial Ordos Basin in the Eastern Tethys were correlated with marine and other terrestrial successions. The three significant NCIEs in the study section were consistently correlated with those in the CPE successions of Europe, the UK, and South and North China. The U-Pb geochronology indicates a Ladinian–Carnian age for the Chang 7 Member. A comprehensive overview of the geochronology, NCIE correlation, and previous bio- and chronostratigraphic frameworks shows that the Ladinian–Carnian boundary is located in the lower part of Chang 7 in the Yishicun section. HgEF may be a more reliable proxy for tracing volcanic eruptions than the Hg/TOC ratio because the accumulation rates of TOC content largely vary in terrestrial and marine successions. The records of Hg, Hg/TOC, HgEF, and NCIEs in the Ordos Basin aligned with Carnian successions worldwide and were marked by similar anomalies, indicating a global response to the Wrangellia LIP during the CPE. Anoxia, a warm-humid climate, enhancement of detrital input, and NCIEs are synchronous with the CPE interval in the Ordos Basin, which suggests that the CPE combined with the regional Qinling Orogeny should dominate the enhanced rate of terrigenous input and paleoenvironmental evolution in the Ordos Basin.  相似文献   
205.
改刊词   总被引:1,自引:1,他引:0  
新风扑面,春潮涌动.在这万象更新的美好季节,《气象与环境科学》与广大读者见面了,这是河南省气象局业务体制改革的一个亮点.  相似文献   
206.
The C-band wind speed retrieval models, CMOD4, CMOD - IFR2, and CMOD5 were applied to retrieval of sea surface wind speeds from ENVISAT (European environmental satellite) ASAR (advanced synthetic aperture radar) data in the coastal waters near Hong Kong during a period from October 2005 to July 2007. The retrieved wind speeds are evaluated by comparing with buoy measurements and the QuikSCAT (quick scatterometer) wind products. The results show that the CMOD4 model gives the best performance at wind speeds lower than 15 m/s. The correlation coefficients with buoy and QuikSCAT winds are 0.781 and 0.896, respectively. The root mean square errors are the same 1.74 m/s. Namely, the CMOD4 model is the best one for sea surface wind speed retrieval from ASAR data in the coastal waters near Hong Kong.  相似文献   
207.
Based on the sequence data of the nuclear ribosomal DNA internal transcribed spacer(ITS) 1,5.8 S,and ITS 2,the molecular phylogeny was analyzed on Ulvaceae species collected from Qingdao coasts in summer of 2007,including 15 attached Ulva and Enteromorpha samples from 10 locations and 10 free-floating Enteromorpha samples from seven locations.The result supported the monophyly of all free-floating Enteromorpha samples,implying the unialgal composition of the free-floating Enteromorpha,and the attached Ulvaceae species from Qingdao coasts were grouped into other five clades,suggesting that they were not the biogeographic origin of the free-floating Enteromorpha in that season.  相似文献   
208.
Based on the sequence data of the nuclear ribosomal DNA internal transcribed spacer (ITS) 1, 5.8 S, and ITS 2, the molecular phylogeny was analyzed on Ulvaceae species collected from Qingdao coasts in summer of 2007, including 15 attached Ulva and Enteromorpha samples from 10 locations and 10 free-floating Enteromorpha samples from seven locations. The result supported the monophyly of all free-floating Enteromorpha samples, implying the unialgal composition of the free-floating Enteromorpha, and the attached Ulvaceae species from Qingdao coasts were grouped into other five clades, suggesting that they were not the biogeographic origin of the free-floating Enteromorpha in that season. Supported by NSFC (40506030); the Innovative Key Project of the Chinese Academy of Sciences (KZCX2-YW-209); Science & Technology Project of Qingdao City (06-2-2-12-JCH)  相似文献   
209.
Dexing copper deposit is the biggest porphyry copper deposit in China. By researching isotopes of C, Si and Cu from the samples of Tongchang and Fujiawu ore-field, the authors found that δ^13 CpDB values of siderite were close to the δ^13 CpDB value of original magma; δ^30Si values of the samples at the ore-forming stage were close to the δ^30 Si value range of magma, δ^30Si values of partial samples were far away from it; Cu isotopic compositions of massive chalcopyrite formed at the early ore-forming stage are higher than that of veinal chalcopyrite formed at the later ore-forming stage. The results show that ore-forming materials were mainly derived from the porphyry body, and part of them were from wall rock materials.  相似文献   
210.
基于FME语义映射的数据转换及应用   总被引:1,自引:1,他引:0  
在详细介绍FME语义映射和转换规则的基础上,分析了FME的空间数据转换机制和简单语义转换规则的不足,并基于自定义映射文件提出了一种在DOS环境下进行批量数据转换的高效方法,最后以DGN到DWG格式的数据转换实例探讨了实施FME语义转换的具体步骤。  相似文献   
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