喀喇昆仑山厦呈、吕莫慕士塔格山段现代冰川分布及变化特征          下载免费PDF全文

阎永忠  马露  吕俊娥 《中国地质调查》2017,4(3):46-50

在全球气候普遍变暖、冰川大面积退缩的大背景下,为揭示山岳冰川十分发育的喀喇昆仑山脉现代冰川分布及变化特征,以中等空间分辨率(ETM和Landsat 8)卫星数据为主要数据源,采用人机交互式解译方法完成了厦呈慕士塔格山、吕莫慕士塔格山段冰川变化遥感调查,基本查明了区内冰川面积、分布特征和变化状况,共调查1 373处冰川,其中中国境内有554处,境外克什米尔印控区有819处; 同时对区内典型冰川变化进行了2期对比分析,得出冰舌退缩、前进或稳定现象同时存在的结论,为喀喇昆仑山脉冰川变化研究提供了参考依据,为我国西部边海防地区水资源的开发利用和冰雪灾害的防治等提供了科学依据。  相似文献   

Tornado hazards on June 23 in Jiangsu Province,China: preliminary investigation and analysis     

Lyu  Hai-Min  Wang  Guo-Fu  Cheng  Wen-Chieh  Shen  Shui-Long 《Natural Hazards》2017,85(1):597-604

This paper reported a tornado hazard happened on June 23, 2016, in Yancheng city, Jiangsu Province. The moving footprint of this huge tornado was from west to east. Shuoji, Chenliang, Goudun, Banhu, Xingou, Wutan towns in Funing district and Sheyang town in Sheyang district were severely hit by this tornado. This tornado along with rainstorm and hailstorm had claimed 99 lives and caused more than 3800 flats to collapse as well as damaged 48 high-voltage circuits. As the cold air from northwest met the subtropical high pressure system that forms over relatively cool water bodies (i.e., Indian and Pacific Oceans), such a powerful meteorological phenomenon was initiated. The strong connective airflow intensified the development of this tornado. Based on the preliminary investigation and analysis of this tornado, cost-effective timber structures with adequate anchorage of the framing to foundations and adequate connection between walls and roofs may be recommended to ensure occupants safety and reduce potential damage in these extreme wind events. Additionally, it is suggested to utilize early warning system along with geographical information system (GIS), Global Positioning System (GPS), and remote sensing (RS) (3S) to monitor and precast the occurrence of rainfall, hailstorm, and tornado hazards in future.

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成都平原粘性土动力学参数统计分析   总被引：4，自引：3，他引：1  

史丙新  周荣军  吕悦军  李建亮  亢川川  孔军 《震灾防御技术》2015,10(2):305-315

成都平原地震构造环境主要受近场中强地震和外围大地震的影响。成都平原内的第四系分布广泛,主要为河流相的砂卵石层夹粘土、粉土层。这种地层在土层地震反应计算时往往会产生一个峰值,具有显著的放大作用。本文共收集了107组土动力学参数的实验资料,统计分析了粉质粘土和粘土两种粘性土的实测土动力学参数,给出了它们在不同深度的动剪切模量比和阻尼比的统计值。然后,选取1个典型钻孔,建立了土层地震反应分析模型,分别运用本文"统计值"、"十五结果"、"规范值"、"推荐值"进行地震土层反应计算,从反应谱形状、地表峰值加速度和反应谱特征周期等方面,验证了本文"统计值"的适用性和针对性,结果表明在盆地内使用"规范值"和"推荐值"时应谨慎,不然可能会对工程的抗震设防产生不利的影响。本文的"统计值"比"规范值"和"推荐值"更适用于成都平原地区,对各类工程建设的场地地震安全性评价具有一定的借鉴和参考价值。  相似文献   

轻便型变形监测雷达的研制与基本性能测试     

张涛  姚宜斌  邹进贵  周吕  徐进军 《测绘工程》2019,28(5):39-43,50

本文介绍自主研发的轻便型变形监测雷达的原理结构和特点,并通过一系列实验对该雷达进行基本物理参数和精度的初步测试以及建筑物变形监测方面的应用实验。通过实验证明,该雷达的测量精度达到0.1mm,最远可以观测到800m外的目标,可以用于建筑物变形监测,该雷达也用于边坡、大坝、桥梁等目标的远程变形监测。同时,该雷达在重量、体积、功耗等方面有着优势,解决同类产品笨重、难以携带作业的问题。  相似文献   

Effects of Degrees of Motion Freedom on Free-Fall of A Sphere in Fluid     

Lei Liu  Jian-min Yang  Hai-ning Lyu  Xin-liang Tian  Tao Peng 《中国海洋工程》2018,32(5):605-613

Free-fall of a sphere in fluid is investigated at a Galileo number of 204 by direct numerical simulations (DNS). We mainly focus on the effects of different degrees-of-freedom (DOFs) of the sphere motion during free-fall. The characteristics of free-fall are compared with those of flow past a fixed sphere. Additional numerical tests are conducted with constraints placed on the translational or rotational DOFs of the sphere motion to analyze different DOFs of sphere motion. The transverse motion contributes significantly to the characteristics of free-fall; it results in the retardation of the vortex shedding, leading to the decrease of the Strouhal number. In addition, the transversal sphere motion exhibits the tendency to promote the sphere rotation. On the contrary, the effects of the sphere rotation and vertical oscillations during free-fall are negligible.  相似文献   

Review of Rapid Transformation of Floodplain Wetlands in Northeast China: Roles of Human Development and Global Environmental Change     

Xiaofei Yu  Shanshan Ding  Yuanchun Zou  Zhenshan Xue  Xianguo Lyu  Guoping Wang 《中国地理科学(英文版)》2018,28(4):654-664

Northeast China is the region with the largest area of wetlands in China. The Sanjiang Plain and the Songnen Plain are large freshwater marsh distribution regions that are affected by climate warming and by the increasing frequency and density of extreme weather and are the regions most subject to disturbances by human activities in Northeast China. The wetlands of the Sanjiang Plain and the Songnen Plain have shrunk severely in the past 60 years, and wetland functions have been reduced substantially because of climate change, unreasonable land use, fire episodes, engineering and construction works and urbanization. Large-scale agricultural development started in the 1950s has been the most important driving factor for wetland loss and degradation in the Sanjiang Plain. Water shortage has been the most important factor for degradation and fragmentation of wetlands in the Songnen Plain. To mitigate wetland degradation and better protect wetlands, special regulations, long-term mechanisms and technical support of wetland protection should be established. A wetland compensation program should be implemented, and technologies for increasing the adaptive capacity of wetlands should be developed. Moreover, it is most important to find the balanced threshold between agricultural development and wetland protection.  相似文献   

自贡市臭氧浓度变化特征及其与气象因素的相关性研究     

吕长春 《气象与环境科学》2021,44(3):47-53

根据2014-2018年自贡市逐日大气污染物监测数据及地面气象数据,采用统计方法,分析了自贡市臭氧变化特征及其与气象因素的关系,结果表明:2014-2018年内自贡市O3-8h(1日中最大连续8 h O3浓度均值)月平均浓度峰值出现在7月份,从年平均浓度变化上看,自贡市O3-8h浓度每年平均增长10.6μg/m3.各季...  相似文献   

浙江东钱湖底泥污染物分布特征与评价   总被引：4，自引：0，他引：4  

程南宁  李巍  冉光兴  杜心慧  曹卉 《湖泊科学》2007,19(1):58-62

对东钱湖底泥做了全面调查,测定了底泥粒度组成、有机质、TN、TP及重金属含量,分析了底泥沉积特性及污染物分布特征,分别采用潜在生态危害指数(RI)法和相对背景值法对重金属污染风险和有机污染及营养盐污染进行了评价.研究结果表明:东钱湖底泥组成以细颗粒为主,重金属含量除镉污染达到中等生态危害程度外,其余均处于较低水平,湖区底泥中有机污染和氮污染问题非常突出.为有效治理东钱湖内源污染,有必要开展包括生态疏浚在内的内源污染治理措施.研究为进一步开展东钱湖水环境治理提供了理论依据.  相似文献   

乡村文化记忆的场域认知、依恋与传承关系 ——以苏州金庭镇为例     

吕龙  陈晓艳 《热带地理》2021,41(3):485-494

以苏州金庭镇居民为研究对象,利用问卷及访谈数据,通过结构方程模型甄别场域认知、地方依恋和传承途径的维度差异,验证彼此的影响路径和作用关系.研究表明:1)居民对乡村文化记忆的场域认知包括纪念性场地、村落型场地、自然型场地和软记忆场等维度,其中,前三者对软记忆场有着正向显著影响;2)乡村文化记忆场域认知是居民地方依恋构建的...  相似文献   

Apodized Lyot coronagraph for SPHERE/VLT: II. Laboratory tests and performance     

G��raldine Guerri  Jean-Baptiste Daban  Sylvie Robbe-Dubois  Richard Douet  Lyu Abe  Jacques Baudrand  Marcel Carbillet  Anthony Boccaletti  Philippe Bendjoya  Carole Gouvret  Farrokh Vakili 《Experimental Astronomy》2011,30(1):59-81

SPHERE (which stands for Spectro-Polarimetric High-contrast Exoplanet REsearch) is a second-generation Very Large Telescope (VLT) instrument dedicated to high-contrast direct imaging of exoplanets whose first-light is scheduled for 2011. Within this complex instrument one of the central components is the apodized Lyot coronagraph (ALC). The principal aim of this paper is to report the first laboratory experiment of the ALC designed for the SPHERE instrument. The performance and sensitivity of the optical configuration was first numerically studied with an end-to-end approach (see the results in paper I subtitled ??Detailed numerical study??). Made confident by the results, we then tested a prototype on an infrared coronagraphic bench. We measured the transmission profiles of the apodizer prototype and the coronagraphic performance of the apodized Lyot coronagraph in Y, J, and H bands. The coronagraph sensitivity to lateral and longitudinal misalignments of its three main components (apodizer, coronagraphic mask and Lyot stop) was finally studied in H band. We can conclude that the prototype meets the SPHERE technical requirements for coronagraphy.  相似文献