极区冬季电离层加热实验研究（三）——低电离层分析   总被引：1，自引：1，他引：0       下载免费PDF全文

徐彬  王占阁  许正文  吴振森  吴健  吴军  薛昆  车海琴  闫玉波 《地球物理学报》2010,53(6):1263-1268

使用低电离层加热条件下,非麦克斯韦碰撞等离子体非相干散射的理论模型,我们对我国2008年1月进行的极区冬季电离层加热实验进行了分析.分析结果表明,本次实验在低电离层区域得到了显著的电子温度增强现象,最大增幅百分比达到了168.9%.基于上述理论模型,我们进一步反演了非麦克斯韦指数,并由其计算出了加热电场强度,这对电离层加热的精确数值仿真有着重要的意义.  相似文献   

基于碳纤维加热光缆的砂性土渗流场C-DTS分布式监测试验研究   总被引：1，自引：0，他引：1  

严珺凡  施斌  曹鼎峰  魏广庆  朱鸿鹄 《岩土力学》2015,36(2):430-436

岩土体中渗流场的监测是岩土工程防灾减灾中一项必不可少的基础工作。在总结已有监测方法优缺点的基础上,提出了渗流场碳纤维加热光缆的分布式温度光纤感测技术（简称C-DTS）;介绍了该方法的监测原理;提出了温度特征值（ ）的概念;设计了砂性土渗流模拟装置,并对砂性土中不同渗流速率下的渗流场进行了室内试验。通过试验确定了 与渗流速率（V）之间存在线性关系;证明了碳纤维加热光缆能够有效地提高DTS监测的敏感性,可实现渗流速率的分布式监测。对该方法应用于工程实践还需要开展的研究工作进行了分析。  相似文献   

The evolution of planets. Venus as the Earth’s probable future     

N.L. Dobretsov 《Russian Geology and Geophysics》2017,58(1):1-11

The general evolution of planets in the Solar System is discussed with a focus on the structure and history of Venus compared with the Earth. The history of the planets of the terrestrial group has been similar and included at least six correlated stages. Many common features the terrestrial planets shared in their early and late evolution have been due to their common origin from the protoplanetary gas-and-dust nebula and plume magmatism widespread on all the planets of the terrestrial group. The characteristic features of the structure and evolution of Venus are most brightly manifested in the specific composition of its atmosphere and of plume magmatism. Venus, with its surface as hot as 450 °C and the near-surface pressure of 92-93 bars, has a hot and dense atmosphere 93 times that of the Earth in mass. Most of its atmospheric mass (99%) belongs to the 65-km thick troposphere consisting of CO₂ (96.5%) and N₂ (3.5%). The upper troposphere includes a 25-30 km thick cloud layer composed mainly of sulfuric acid droplets, water vapor, and SO₂. At a height of 49.58 km, the clouds approach the conditions of the terrestrial surface and might be hospitable to bacterial life. Volcanism, the most active and widespread process of Venusian geology, maintains continuous SO₂ emission. There are diverse volcanic edifices on Venus, which are most often large and are similar to the Earth’s plume-related volcanoes. The evolution before 1 Ga, as well as the share and the role of alkaline rocks and carbonatites among its volcanics, are among the most debatable issues about Venus. Being located closer to the Sun, Venus cooled down more slowly and less intensely than the Earth after the primary accretion. In the Proterozoic, it began heating and reached its present state at ~ 1 or 2 Ga. In the future, as the Sun becomes a red giant, the Earth is predicted to begin heating up in 500-600 Myr to reach the temperature of present Venus in about 1.5 Gyr.  相似文献   

Effect of lead core heating on the seismic performance of bridges isolated with LRB in near‐fault zones     

Gokhan Ozdemir  Murat Dicleli 《地震工程与结构动力学》2012,41(14):1989-2007

In this paper, the effect of lead core heating and associated strength deterioration on the seismic response of bridges isolated with lead rubber bearings (LRB) is investigated as a function of the characteristics of the isolator and near fault ground motions with forward rupture directivity effect. Furthermore, the ability of bounding analyses to provide a design envelope for maximum isolator force and maximum isolator displacement is verified. For this purpose, a series of nonlinear dynamic analyses are conducted for LRB isolated bridges where both deteriorating and non‐deteriorating force‐deformation relationship of LRB were employed. The analyses are performed for both simulated and recorded ground motions. It is found that while the temperature rise in the lead core generally increases with increasing magnitude and number of near fault ground motion velocity pulses, it decreases with larger distances from the fault. It is also found that bounding analysis method provides conservative (envelope) estimates of maximum isolator displacement and maximum isolator force for design purposes that fulfill its intended purpose. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

含天然气水合物沉积物分解过程的有限元模拟   总被引：1，自引：0，他引：1  

吴二林  魏厚振  颜荣涛  韦昌富 《岩土力学》2012,33(9):2811-2821

温度和压力的变化会引起含天然气水合物沉积物的分解,其过程伴随着相态转换、孔隙水压力和气压力耗散、热传导、骨架变形等过程的相互耦合作用。基于多孔介质理论建立了描述含天然气水合物沉积物分解过程的数学模型,考虑了水合物分解产生的水、气流动、水合物相变和分解动力学过程、热传导、骨架变形等过程的耦合作用。基于有限元法,建立了模拟水合物分解过程的数值模型,并编制了计算机分析程序。通过对降压法和升温法开采过程的数值模拟,揭示了在水合物分解过程中沉积物储层的变形、压力、温度等因素的变化规律。结果表明：降压法和升温法都会导致储层变形以及产生超孔隙压力,但两种方法作用效果不同;同时,水合物分解过程包含渗流及热传导作用。  相似文献   

生活方式对开封城市家庭采暖碳排放的影响     

张艳 《地理科学进展》2013,32(7):1072-1081

随着城市化进程的加快和家庭采暖用能消费量的不断提高, 家庭采暖用能碳排放对环境造成的胁迫效应日益凸显。尽管家庭采暖碳排放问题引起众多学者的关注, 但深入探讨微观家庭采暖用能碳排放机理研究仍然缺乏。根据生活方式对家庭采暖碳排放影响的理论分析, 构建城市家庭采暖碳排放影响因素研究模型, 以暖温带典型城市——开封市为例, 基于792 户家庭样本的调查数据, 探究生活方式与家庭人均采暖CO₂排放之间的关系。借助数据统计和多元回归分析发现:① 家庭采暖生活方式各因子与人均采暖CO₂排放量之间的关系密切, 随着各因子的变化, 家庭人均采暖CO₂排放量呈现出规律性变化;② 生活方式各因子均为影响家庭人均采暖CO₂排放的显著因子, 其中, 住房面积、采暖形式、采暖期长度、人口规模等因素对家庭人均采暖CO₂排放的影响程度较大。建议采用低碳采暖形式, 以降低家庭采暖碳排放量。  相似文献   

凝结加热条件下垂直切变基本流中的混合波不稳定研究     

安洁  张铭  齐琳琳 《热带气象学报》2013,29(4):616-624

在实际大气中凝结加热对中尺度系统的发展起着重要作用,通过数值计算方法研究了扰动的波谱和谱函数,重点讨论在凝结加热条件下扰动不稳定的性质及特征。研究结果表明:考虑凝结加热时,在相同垂直切变条件下,随着波长的减小,不稳定增长率增大,即加热放宽了不稳定出现的条件,且尺度越小的扰动,对不稳定的条件要求越低。当Nse2 <0时,在大尺度和中α尺度波段,风切变有利于不稳定的发展,由风切变造成的动力学不稳定是主要的,而凝结加热造成的热力学不稳定处于次要地位;而在中β尺度波段,风切变则抑制不稳定发展,此时凝结加热造成的热力学不稳定处于主要地位。   相似文献   

Pore structure of selected Chinese coals with heating and pressurization treatments     

CAI YiDong  LIU DaMeng  PAN ZheJun  YAO YanBin  LI JunQian  QIU YongKai 《中国科学:地球科学(英文版)》2014,57(7):1567-1582

Pore structure of Chinese coals with heating and pressurization treatments was studied using small angle X-ray scattering(SAXS),N2adsorption/desorption isotherms and scanning electron microscope(SEM).SAXS was performed for some samples after heat treatment at seven elevated temperatures from 25 to 250°C at 0 MPa and for other samples with hydrostatic pressure treatment at 0,5,10,15 and 20 MPa at the room temperature.The results show that N2adsorption isotherm together with SAXS could be a comprehensive method to evaluate the pore shape and the pore size distribution:the pore shapes are generally spherical for low rank coal and they are mainly ellipsoidal for high rank coal.All these measurements were then interpreted using the fractal theory to reveal relationship between surface fractals and coal rank,and the evolution of surface fractals under heating and pressurization treatments.The results show that surface fractal dimension(Ds)changes with different treating temperature and pressure and maximum vitrinite reflectance(Ro,m).Especially in the bituminous stage,Ds shows an increasing trend with Ro,m under varied temperatures.Moreover,Ds shows an increasing trend with increasing temperature before 200°C,and a decreasing trend after 200°C.Furthermore,the results show that Ds has a more complex relationship with Ro,m under varied treating temperature than that under varied treating pressure.  相似文献   

Lead core heating in lead rubber bearings subjected to bidirectional ground motion excitations in various soil types          下载免费PDF全文

Gokhan Ozdemir 《地震工程与结构动力学》2014,43(2):267-285

This paper investigates the response of lead rubber bearings (LRBs) under bidirectional earthquake excitations when lead core heating effect is of concern. For this purpose, a series of nonlinear response history analyses were conducted with a bilinear force‐deformation relation for LRBs. In the considered bilinear representation, the strength of LRBs deteriorates because of lead core heating under cyclic motions. Response of LRBs was studied in terms of maximum isolator displacements (MIDs) and maximum lead core temperature as a function of isolator characteristics (characteristic strength to weight ratio, Q/W, and post‐yield isolation period, T). Nonlinear response history analyses were performed using two sets of ground motions clustered according to their soil classifications. To quantify the interacted effects of coupled analysis and lead core heating on MID, unidirectional analyses were also performed. Furthermore, the efficacy of equivalent lateral force procedure in estimating the MID of LRBs was also tested for the cases in which temperature‐dependent behavior of LRBs was considered. The results demonstrate that the temperature rises in the lead core of LRBs in bidirectional analyses are approximately 50% higher than that of unidirectional ones. It decreases with increasing Q/W ratio and T. It is also revealed that equivalent lateral force procedure gives close estimations for MID with some overestimation even for temperature‐dependent behavior of LRBs. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

用大气热源表征的东亚夏季风指数的研究   总被引：1，自引：0，他引：1  

陈中钰  巩远发  赵蕾 《成都信息工程学院学报》2010,25(3):275-280

利用1965—2007年NCEP／NCAR再分析资料和同期的中国160站降水资料,在讨论大气热源的气候特征基础上,用整层积分的大气热源定义了一个东亚夏季风指数,并用该指数研究了东亚夏季风和中国气候的关系。研究表明：定义的大气热源季风指数能反映夏季风的异常变化,高（低）指数年对应的东亚夏季风偏强（弱）;该指数与长江中下游降水存在高度的同期负相关,对长江中下游夏季降水有较强的分辨能力。  相似文献