基于COMSOL的板式电涡流阻尼器数值模拟分析

电涡流阻尼器具有无需与结构接触、无磨损的特点,不存在如黏滞阻尼器容易出现漏液等问题。为了研究板式电涡流阻尼器的性能,首先对板式电涡流阻尼器的理论进行简述;然后基于电涡流阻尼系数测定试验,对采用COMSOL进行电涡流阻尼模拟方法和模型的可靠性进行验证;最后采用COMSOL和验证后的模拟方法对板式电涡流阻尼器的导磁间隙、导体板厚度、导体板背铁厚度、磁铁背铁厚度等进行参数分析。验证板式电涡流阻尼基本符合黏滞阻尼理论的假定,也证明采用COMSOL进行阻尼系数模拟的结果是可信的;分析发现导磁间隙和导体板厚度均对阻尼系数影响较大,而导体板和磁铁背铁的厚度对阻尼几乎没有影响。     

Subduction-zone peridotites and their records of crust-mantle interaction

Subduction is the core process of plate tectonics. The mantle wedge in subduction-zone systems represents a key tectonic unit, playing a significant role in material cycling and energy exchange between Earth's layers. This study summarizes research progresses in terms of subduction-related peridotite massifs, including supra-subduction zone(SSZ) ophiolites and mantle-wedge-type(MWT) orogenic peridotites. We also provide the relevant key scientific questions that need be solved in the future. The mantle sections of SSZ ophiolites and MWT orogenic peridotites represent the mantle fragments from oceanic and continental lithosphere in subduction zones, respectively. They are essential targets to study the crust-mantle interaction in subduction zones. The nature of this interaction is the complex chemical exchanges between the subducting slab and the mantle wedge under the major control of physical processes. The SSZ ophiolites can record melt/fluid-rock interaction, metamorphism,deformation, concentration of metallogenic elements and material exchange between crust and mantle, during the stages from the generation of oceanic lithosphere at spreading centers to the initiation, development, maturation and ending of oceanic subduction at continental margins. The MWT orogenic peridotites reveal the history of strong metamorphism and deformation during subduction, the multiple melt/fluid metasomatism(including silicatic melts, carbonatitic melts and silicate-bearing C-HO fluids/supercritical fluids), and the complex cycling of crust-mantle materials, during the subduction/collision and exhumation of continental plates. In order to further reveal the crust-mantle interaction using subduction-zone peridotites, it is necessary to utilize high-spatial-resolution and high-precision techniques to constrain the complex chemical metasomatism, metamorphism,deformation at micro scales, and to reveal their connections with spatial-temporal evolution in macro-scale tectonics.     

CT扫描参数优选对辐射防护的贡献

作者参照国际放射防护委员会(ICRP)1991年60号出版物规定的实践中放射防护原则,设计CT扫描中患者及公众放射防护方策,通过优选予置扫描参数和适时扫描参数,降低CT 受检者的辐射剂量,并业已经过辐射测量实验结果的证实。对此,做一介绍。     

地震活动图像分析预测汶川8．0级地震的回顾与思考

本文回顾了2008年5月12日四川省汶川8．0级特大地震前中长期及年度趋势预测过程。作者根据地震活动图像特征作出了较好预测,明确指出四川石棉-冕宁和汶川-松潘一带,2008年前后,可能发生7级以上地震。但带短期预测特点的2008年度大震危险性,作者没有作出确切的预测。本文思考了相关的经验教训并对改进分析预报工作提出了构想。     

利用背景噪声层析成像方法反演新疆天山及邻区S波速度结构

利用新疆地震台网52个固定台站和天山地区新布设的11个流动台为期1年的观测数据,采用背景噪声层析成像方法获得了天山及邻区(41°～48°N,79°～91°E)10～50s的瑞利面波相速度分布图像,使用基于贝叶斯的马尔科夫链蒙特卡洛(MCMC)方法反演得到研究区地壳上地幔S波速度结构.研究结果表明,准噶尔盆地沉积盖层南深...     

菌藻共固定化降解微囊藻毒素

研究了微囊藻毒素降解菌S3和椭圆小球藻L1共固定化后,对微囊藻毒素(MC-LR)的降解作用.结果表明,共固定化藻菌体系比单独固定化菌对MC-LR有更好的降解效果,共固定的藻可促进降解菌S3的生长.固定化细胞对毒素的降解能力较稳定,受环境温度和pH变化的影响较小,重复使用仍可维持较高的降解活性.     

New equation to decipher the relationship between carbon isotopic composition of methane and maturity of gas source rocks

The identification of the origin and source of natural gas is always a difficult and hot issue.Hereinto,the maturity identification is one of the most important scientific problems.Many empirical equations have been established to decipher the relationship between the maturity of gas source rocks and the carbon isotopic composition of natural gas.However,these equations proposed often fail to identify the maturity of the source rocks correctly,which in turn prevents the identification of genetic types and source rocks of the natural gas because the petroliferous sedimentary basins in China are complex and diverse,with multiple sets of source rocks and different thermal history.In this paper,the oil-associated gas from the Permian lacustrine source rocks and the coal-derived gas from the Jurassic source rocks in Junggar and Turpan-Hami basins have been investigated to decipher the relationship between the maturity(vitrinite reflectance)of gas source rocks and the carbon isotopic composition of methane.The equations established areδ¹³C₁=25lgR_o-42.5 for oil-associated gas,andδ¹³C₁=25lgR_o-37.5 for coal-derived gas.These new equations are suitable for the maturity identification of source rocks in most petroliferous basins,and favorable for the identification of the genetic type and source of natural gas,which is very important to improve the geological theory of natural gas.     

Assessing spatial likelihood of flooding hazard using naïve Bayes and GIS: a case study in Bowen Basin,Australia

Flooding hazard evaluation is the basis of flooding risk assessment which has significances to natural environment, human life and social economy. This study develops a spatial framework integrating naïve Bayes (NB) and geographic information system (GIS) to assess flooding hazard at regional scale. The methodology was demonstrated in the Bowen Basin in Australia as a case study. The inputs into the framework are five indices: elevation, slope, soil water retention, drainage proximity and density. They were derived from spatial data processed in ArcGIS. NB as a simplified and efficient type of Bayesian methods was used, with the assistance of remotely sensed flood inundation extent in the sampling process, to infer flooding probability on a cell-by-cell basis over the study area. A likelihood-based flooding hazard map was output from the GIS-based framework. The results reveal elevation and slope have more significant impacts on evaluation than other input indices. Area of high likelihood of flooding hazard is mainly located in the west and the southwest where there is a high water channel density, and along the water channels in the east of the study area. High likelihood of flooding hazard covers 45 % of the total area, medium likelihood accounts for about 12 %, low and very low likelihood represents 19 and 24 %, respectively. The results provide baseline information to identify and assess flooding hazard when making adaptation strategies and implementing mitigation measures in future. The framework and methodology developed in the study offer an integrated approach in evaluation of flooding hazard with spatial distributions and indicative uncertainties. It can also be applied to other hazard assessments.     

城市地铁爆破开挖对浅埋地下大直径管道的安全影响研究

在城市浅埋地铁爆破开挖中,经常遇到地下管网、涵洞等构筑物,而爆破地震效应对其影响范围和程度的正确评价就显得尤为重要。本文以长沙地铁爆破开挖为例,以现场实测数据为基础,采用有限单元法,对爆破振动下大直径混凝土污水管道的动力响应、变形和动应力等进行了计算,评价了爆破地震对管道的安全影响。研究表明:管道在控制爆破作用下是偏于安全的;爆心距是影响管道受到爆炸作用力影响大小的最主要因素;对于以实测数据为基础,采用加速度激励的时程分析方法以爆破振动对埋地管道的影响进行评价,是一种可行且较为精确的方法。     

镇江地震台网理论监测能力评估

基于近震震级公式,对镇江地震台网理论监测能力进行评估,绘制地震监测能力图,以确定监测区不同地点发生地震时能被台网有效分析和定位的地震最小震级。镇江市句容县在该台网理论监测震级最小,为ML1.2—1.3;在镇江及相邻城市,发生M_L 1.8分析认为,以上地震均能被有效监测。