First record of Odontaster penicillatus populations (Philippi, 1870) (Echinodermata: Asteroidea) in the Atacama and Antofagasta regions,Chile (Southeast Pacific)     

Leonardo Campos  Fernando Berrios  Brenda B. Hermosillo-Nú?ez  Marco Ortiz 《海洋学报(英文版)》2022,41(12):152-155

We report for the first time the presence of local populations of the starfish Odontaster penicillatus in the regions of Atacama and Antofagasta, Chile. This finding indicates an extension of the distribution limit of 500 km with respect to the last observation made in 2007 in Isla Grande de Atacama. A total of 121 specimens of O. penicillatus were recorded at depths of between 8 m and 24 m. They were associated with rocky substrate and with different species of barnacles, sponges and bryozoans. The presence of O. penicillatus expands the knowledge of the benthic biodiversity of the region, and the development of studies on its ecological importance will be promoted.  相似文献   

厦门近海尖梭螺属(软体动物门, 腹足纲, 梭螺科)一新记录种     

陈志云  郭翔  刘毅  尉鹏  张素萍 《热带海洋学报》2022,41(2):189-192

在福建厦门近海采集到梭螺科Ovulidae尖梭螺属Cuspivolva 中国海新记录种1种, 即武装尖梭螺Cuspivolva bellica (C. N. Cate, 1973)。标本采自厦门近海低潮线附近, 栖息于鞭柳珊瑚Ellisella sp.的枝杈表面, 现保存于中国科学院南海热带海洋生物标本馆。本文对此新记录种的外部形态、生活习性和地理分布等进行了描述和记录, 并与近似种进行了比较和讨论。截至目前, 我国已知尖梭螺属共8种, 该新记录种的发现和报道, 进一步丰富了我国海域梭螺科物种的多样性。  相似文献   

历史遗留围填海生态保护修复工作探讨——以晋江盐场围填海项目为例          下载免费PDF全文

李婵娟  吴耀建  李青生  方婧  郭洲华  戴娟娟 《应用海洋学学报》2022,41(1):60-68

本研究以晋江盐场围填海项目为例,针对项目情况和区域环境特征,在收集现有资料和补充调查的基础上,分析评估了围填海工程建设的海洋生态影响,并提出了相应的生态保护修复方案。在此基础上,提出了今后工作的建议:①保护修复应推行整体保护、系统修复的有效机制,实现区域生态系统的恢复与良性发展。②围填多年已经形成相对稳定的生态系统的围填海项目,制定修复对策也应遵循现有的生态条件,充分考虑修复工程的成本与效益,增强修复方案的可操作性,做出最有利的决策。③生态修复模式应以自然恢复为主、人工修复为辅,最大程度恢复生态系统功能。本研究可为类似生态保护修复工作提供借鉴。  相似文献   

Martian northern polar cap: Layering and possible implications for radar sounding     

Yaroslaw A. Ilyushin 《Planetary and Space Science》2004,52(13):1195-1207

The propagation of electromagnetic waves in the northern polar ice sheet of Mars is considered. It is shown that the dispersion and attenuation of radio waves in the polar sheet are regulated by two groups of factors: the physical and chemical composition of the ice, and the geometrical parameters of the layered structure of polar sheet. Both analytical and numerical simulations of ultra wide band chirp radar pulse propagating through the cap are performed. Wide variety of combinations of the physical and geometrical parameters of the ice sheet, consistent with previously published observational data, has been considered. The frequency bands of transparency and opacity of the northern ice sheet for radar signals were found. The side clutter for this particular region of the planet is studied.  相似文献   

混凝土大坝原型测量及抗震分析     

王岚  谢建清 《大地测量与地球动力学》2001,21(4):87-94

以丹江口大坝、葛州坝闸墩坝、新丰江大坝和潭岭大坝强震观测为例 ,介绍了混凝土大坝原型观测中所使用的仪器、测量方法 (强震观测和微振观测 )及获取的初步成果 ,扼要介绍了混凝土大坝抗震分析的内容 (包括结构动力特性分析、坝体稳定性分析和强度验算 )和方法 (拟静力法和反应谱法 ) ,最后 ,详细介绍了利用强震记录对新丰江大坝和潭岭大坝进行抗震分析的结果 ,并由此看出强震观测对于大坝抗震的重要性  相似文献   

Leachate Lithium Characteristics of Loess-paleosol Sequences on the Chinese Loess Plateau and their Paleoclimatic Significance     

JIA Peng  FU Chaofeng  HE Maoyong  LIU Junfeng  LIU N  LI Yulong  YANG Kaiyuan 《《地质学报》英文版》2023,97(6):1814-1824

The geochemical components of the leachate from loess-paleosol deposits can provide information about climate-related post-depositional processes. For example, leachate lithium ([Li]leachate) is a potential paleoclimate proxy because lithium is a typical lithophile element that is readily adsorbed by clay minerals during weathering and pedogenesis, and thus stratigraphic variations in [Li]leachate can reflect these processes. We investigated the [Li]leachate values of two loess-paleosols profiles (the Luochuan and Weinan sections), on a north–south climatic gradient on the Chinese Loess Plateau. Independent paleoclimate information was provided by measurements of magnetic susceptibility, grain size, Rb/Sr ratios, and clay mineral content. During the last glacial-interglacial period, [Li]leachate increased from 0.39 to 1.97 μg/g at Luochuan and from 0.67 to 2.45 μg/g at Weinan, mainly due to increasing pedogenesis. Based on these results we developed a conceptual model to explain the variations in [Li]leachate. Li+ within loess layers is mainly derived from dust input and the decomposition of primary minerals, influenced by the East Asian winter monsoon, while in paleosol layers Li+ is mainly derived from clay mineral adsorption during pedogenic processes, influenced by the East Asian summer monsoon.  相似文献   

强震下钢筋混凝土框架和砖混结构的动力响应分析——以云南漾濞6.4级地震为例     

张梓荣  王宏伟  陈学良  范志凯 《地球与行星物理论评》2022,53(1):92-100

以2021年5月21日云南漾濞6.4级地震所获取的漾濞台强震动记录作为输入,对不同高度(低层、多层和高层)钢筋混凝土框架结构以及一低层砖混结构进行动力时程分析,探讨不同高度钢筋混凝土框架结构动力响应特点,对比砖混结构与低层框架结构地震响应的不同,并对结构进行性能评定.主要分析结果表明,所有结构的楼层加速度响应中,竖向加速度放大效应显著,尤其是低层框架;框架结构Y方向楼层傅里叶幅值谱峰值主要在1~2.5 Hz频率范围;多层框架的层间位移角响应更大;所有框架结构以及设防的砖混结构层间位移角均未超过中等破坏限值;与低层框架结构相比,基本周期更短的砖混结构水平向楼层加速度放大效应更为显著;设防的砖混结构具有良好的抗震性能.分析结果可为灾区震害评估和震后修复提供指导,同时为建筑结构抗震设计提供一定参考.  相似文献   

东莞市历史建筑数字化保护研究     

高益忠  陈明辉  黄燕 《测绘通报》2021,(7):140-143,149

本文通过对东莞市获批的278处历史建筑的现场调研,采用无人机、三维激光扫描等空间信息技术实现信息采集和数字化建库,结合数字化管理平台与公众服务系统全方位展示和传播东莞市历史建筑的文化价值。旨在探索数字化技术与历史建筑保护相结合的新模式,为传统文化资源的保存、保护、活化利用及传播提供新思路,从而推动历史建筑保护管理工作向科学化、完整化、系统化和共享化方向发展。  相似文献   

客家聚落地名时空分布与演变方法研究     

陈优良  朱倩 《测绘科学》2021,46(2):178-185

针对目前地名文化中客家聚落地名研究的不足,该文从客家迁徙历史的角度,提出了客家地名定性和定量的研究方法,以客家摇篮石城地名为研究对象,采用核密度分析法和多元logit回归模型方法,深入分析石城客家地名的时空分布特征和历史演变因素。结果显示:在时间上,客家地名数量整体呈现上升趋势,增长时间分为5个阶段,隋唐萌芽时期、宋朝大量增长期、元朝缓慢增长期、明朝平稳增长期和清朝快速增长期;在空间上,客家地名分布显现出聚集特征,但聚集程度各异,聚集点和聚集区域随着时间的推移而变化。根据logit模型结果显示,地形、河流、人口和经济等多种因素交融在一起,对客家地名的演化产生了重大而深远的影响。  相似文献   

Variations of southeast Vatnajökull ice cap (Iceland) 1650–1900 and reconstruction of the glacier surface geometry at the Little Ice Age maximum          下载免费PDF全文

Hrafnhildur Hannesdóttir  Helgi Björnsson  Finnur Pálsson  Guðfinna Aðalgeirsdóttir  Snævarr Guðmundsson 《Geografiska Annaler: Series A, Physical Geography》2015,97(2):237-264

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