关于大气环境中PM2.5的研究进展

总结了国内外关于大气环境中PM_2.5的研究进展。针对目前国内大部分城市阴霾天气日益加重,国内相关部门和领域更加重视PM_2.5的监测和研究的现状,调研了国内外大气环境领域关于PM_2.5的研究情况,提出改善空气质量、加强PM_2.5研究的建议。介绍了PM_2.5的定义,指出PM_2.55对人体健康和能见度的不利影响。国内关于PM2.5的研究工作包括：分析PM_2.5和气象条件的关系;PM_2.5的观测特征以及成分和来源分析;开展PM_2.5的数值模拟。叙述了沈阳地区关于PM_2.5的研究情况,指出了改善沈阳城市大气环境的措施,包括加强PM2.5的连续监测,调整产业结构和布局,提高能源效率,发展洁净能源、减少煤炭消费,防治机动车尾气污染。     

The impact of crustal rheology on natural seismicity: Campi Flegrei caldera case study

We analyze the crustal rheology beneath the active resurgent Campi Flegrei caldera(CFc) in Southern Italy by modelling the 3 D brittle-ductile(B/D) transition, based on available thermal, geological and geophysical data. Firstly, the thermal field in the conductive physical regime is modeled using a finite element method; based on an optimization tool, this method is applied to evaluate the location and dimensions of the deep thermal source beneath the caldera. A horizontally-extended thermal anomaly located at about 5000 m depth below sea level is identified beneath Pozzuoli Bay, a part of the CFc. The same isotherm is located at a depth of 20,000 m beyond the caldera. This indicates a higher horizontal temperature gradient in the caldera with respect to the surrounding area. Next, we utilize this thermal model to image the 3D rheological stratification of the shallow crust below the caldera with two different values of strain rates. Within the caldera, the B/D transitions with ε equal to 10^-12 s^-1 and 10^-8 s^-1 are located at 3000 m and 5000 m depths, respectively. Outside the caldera, the transition is very deep(15,000-20,000 m), seemingly uninfluenced by the thermal state of the CFc volcanism. Finally, we compare these results with the spatial distribution of earthquake hypocenters, Benioff strain release and b-value distribution to investigate the relationship between crustal rheology and seismicity characteristics. Our analysis reveals that the image of the B/D transition is in agreement with the distribution of earthquake hypocenters, constraining the potential seismogenic volume of the region. Our study demonstrates that knowledge of the rheological state of a volcanic system is an important element to interpret its dynamic, forecast future activity and improve evaluation of the associated seismic hazard.     

琼中地震台子午项目地磁房建造经验

介绍琼中地震台子午项目地磁房建设建筑材料磁性检测,与施工过程中磁性跟踪检测方法及保温措施,实践证明,方法切实有效,可为其他地磁台站建设提供经验。     

Shear wave velocity structure in western Thessaloniki (Greece) using mainly alternative SPAC method

The aim of the paper is the definition of the material parameters of sediments in the western part of Thessaloniki useful in the prediction of strong ground motion. The region of interest is elongated in the E–W direction and is confined between the Kalochori suburb and the harbor of Thessaloniki, while in the N–S direction it is extended between the coastline and the region of sediments and outcrop rock boundary. Many geological and seismotectonic studies, as well as geophysical surveys with electrical soundings and geotechnical boreholes, contribute to our understanding of the general sedimentary structure. Nonetheless, these studies could not provide any information regarding the material stiffness in terms of shear wave velocity; the most useful parameter in site response studies.     

宽频带数字资料低频波在大震前的短临前兆信息研究

通过对高台、兰州、成都、安西地震台宽频带数字资料在2001年昆仑山口西8.1级地震,2008年汶川8.0级地震以及2003年山丹、民乐6.1级地震前低频波频谱变化的研究,总结了数字资料在频率域上的短临前兆异常特征,发现0.1~0.14 Hz频幅在震前几天成逐渐增强的趋势。并结合震源区构造特征对前兆机理进行了探讨。认为低频波的产生与静地震和慢地震有关。     

Statistics of gravity wave spectra in the troposphere and lower stratosphere over Beijing

We utilize the temperature profiles with a height resolution of 50-m obtained over the Beijing Observatory in the period between January of 2002 and December of 2002 to study vertical wavenumber spectra of normalized temperature fluctuations in the 1.67-8.02 km and 13.57-19.92 km altitude ranges and compare them with linear saturation model.Results indicate that individual vertical wavenumber spectra reveal a considerable variability in both slope and amplitude.The observed variability is not consistent wit...     

电子全站仪在高校田径运动会中的应用研究及推广

与一般简易的测量方式及高级别赛事中的测量方式进行对比,分析了电子全站仪在高校田径运动会中应用的可行性,以及全站仪自身具有的优势与运动测量的融合的必要性。通过野外的测量实验,对跳远和掷标枪项目进行了观测。在采集和处理分析数据基础上,描述了全站仪在田径运动会中的应用,重点叙述了它在田赛领域的应用。最后,提出建议和方案,将电子全站仪测量技术推广形成一种模式,将科技元素投入到高校田径运动会中,发挥它快速、便捷等特性。     

CCD measurements of visual double stars at Calar Alto

342 CCD measurements of relative positions and magnitude differences for 145 visual double stars are presented. Observations were carried out at the 1.23m telescope of the German‐Spanish Astronomical Center at Calar Alto (Spain), all of them in V and R photometric bands.     

微动中多模式面波频散曲线的映射式提取方法

为了避免微动勘探技术中因忽略高阶模式瑞雷波而影响反演精度的不足,提出从微动面波中提取多模式瑞雷波频散曲线的映射式方法.该方法从微动信号入手,首先通过相关法提取多半径台阵的相关系数曲线,然后建立从多条相关系数曲线到多模式瑞雷波频散曲线的映射模型,最后采用分区拟合准则优化实现模型结构,达到提取微动面波中多模式瑞雷波频散曲线的目的.为验证方法的有效性,通过有限差分方法数值计算实际近表面应用中三种常见典型地质结构中的微动信号,采用映射式方法提取微动面波中多模式瑞雷波频散曲线,将提取结果和理论值进行对比分析.结果表明,映射式方法提取微动面波中多模式瑞雷波频散曲线可以满足反演地质结构的要求.     

CSES卫星观测的赤道电集流特征

本文利用2018年8月到2019年12月期间我国张衡一号电磁监测试验卫星(CSES)所观测的地磁数据,反演了赤道电集流(EEJ)电流密度的纬度剖面;通过选取的4729个清晰的EEJ事件,分析了在地方时(LT)14:00附近的EEJ特征.研究结果表明：在地磁平静期间,CSES卫星观测的EEJ电流密度的峰值位于磁赤道附近,其平均幅度约为27 mA·m^-1.该幅度小于CHAMP和Swarm卫星的观测结果,这与2018—2019年期间太阳活动水平较低(平均F_10.7指数约为70 sfu)有关,此外也与CSES轨道所处的地方时相关.平均而言,EEJ的主瓣宽度约为4°,主瓣和旁瓣的峰值电流密度之比约为2.7;在本文所关注的事件中,东向EEJ事件约占83%,西向EEJ事件约占17%;这个比例与CHAMP卫星的观测结果稍有不同,与14:00 LT附近西向EEJ出现的概率较低有关.东向EEJ的峰值电流密度对经度、季节和太阳辐射水平有显著的依赖性.EEJ峰值密度随经度变化呈现明显的4波结构,可归因于低层大气非迁移潮汐的作用.EEJ峰值电流密度有明显的季节依赖,其幅度在春秋分较大,冬夏季较小.在2018—2019年期间,尽管太阳活动水平较低,EEJ峰值密度随太阳辐射水平的增加而增加.