Corotational damping of discoseismic c modes in black hole accretion discs

Discoseismic c modes in accretion discs have been invoked to explain low-frequency variabilities observed in black hole X-ray binaries. These modes are trapped in the innermost region of the disc and have frequencies much lower than the rotation frequency at the disc inner radius. We show that because the trapped waves can tunnel through the evanescent barrier to the corotational wave zone, the c modes are damped due to wave absorption at the corotation resonance. We calculate the corotational damping rates of various c modes using the Wentzel-Kramers-Brillouin (WKB) approximation. The damping rate varies widely depending on the mode frequency, the black hole spin parameter and the disc sound speed, and is generally much less than 10 per cent of the mode frequency. A sufficiently strong excitation mechanism is needed to overcome this corotational damping and make the mode observable.     

江西省地面气象观测站业务系统集成设计

分析了当前基层气象台站观测业务系统现状和存在的多终端问题,在不改变现行观测业务规范的前提下,利用先进的电子、通讯技术和软件设计方法,建立台站多观测系统集成平台,实现各观测项目在单个终端运行,操作人员可以在一个工位上完成所有观测项目的管理和数据处理,以此提高台站观测系统的集约化程度和自动化程度。     

滇西北高原局地暴雨雷达回波特征

利用丽江CINRAD/CC雷达观测资料,并结合天气背景及当地地形,对2008年9月11日出现在华坪站的单点性暴雨天气进行详细分析发现:雷达回波强度场上,由前端积状云和后部层积云组成的混合降水回波移过测站;速度场上出现了"逆风区"的特征,并在其移动路径周围出现了强降水天气;5.2 km以上高度的垂直风廓线显示,冷平流控制时系统维持,冷平流减弱时系统减弱;500 hPa副高较强,冷空气南下回流,致使700 hPa切变线东南移,产生强降水。华坪县特殊的地形与该次暴雨的风场结构相配合形成迎风坡的动力抬升条件,是此次暴雨的又一特征。     

复杂天气交替出现的观测编报技术应注意的问题

如何在短短的十几分钟观测发报时间内能把恶劣天气准确编报,并对观测编报技术提供可借鉴的经验.     

新建社区的地震应急避难规划研究

人员密集、用地集约、功能混合是近年来新建社区的共同特点,一旦地震大灾在没有任何应急准备的情况下发生,社区居民的震时疏散和震后安置将面临很大困难。本文分析了新建社区的开发模式特点、脆弱性和应急避难需求,提出了新建社区地震应急避难规划设计的五点原则:安全第一、因地制宜、优化分区、有机整合和家喻户晓。通过大连市万科海港城一期地震安全示范社区"应急避难规划设计方案"实例,说明依据上述原则开展空间布局等"硬"规划和实施机制等"软"规划的具体方法,验证了规划原则的可操作性和对于管理、规划、建设防灾减灾城市的积极作用。     

An overview of developments and applications of oceanographic radar networks in Asia and Oceania countries

More than 110 radar stations are in operation at the present time in Asia and Oceania countries, which is nearly half of all the existing radar stations in the world, for purposes related to marine safety, oil spill response, tsunami warning, coastal zone management and understanding of ocean current dynamics, depending mainly on each country’s coastal sea characteristics. This paper introduces the oceanographic radar networks of Australia, China, Japan, Korea and Taiwan, presented at the 1st Ocean Radar Conference for Asia (ORCA) held in May 2012, Seoul, Korea, to share information about the radar network developments and operations, knowledge and experiences of data management, and research activity and application of the radar-derived data of neighbouring countries. We hope this overview paper may contribute as the first step to promotion of regional collaborations in the radar observations and data usages and applications in order to efficiently monitor the coastal and marginal sea waters along the western Pacific Ocean periphery.     

Constraints from strontium and neodymium isotopic ratios and trace elements on the sources of the sediments in Lake Huguang Maar

The sediments in Lake Huguang Maar in coastal South China were previously thought to originate mainly from wind-blown dust transported from North China, such that the lake sediments recorded the varying strength of the Asian winter monsoon. An alternative explanation was that the local pyroclastic rocks supplied the lake sediments, but the actual contributions from the different sources remained unclear. Geochemical analyses including ⁸⁷Sr/⁸⁶Sr and ¹⁴³Nd/¹⁴⁴Nd and trace elements support the local pyroclastic rock as the dominant source: < 22% of the total Sr in the lake sediments and  17% of the Nd arises from the distant source. Nb/Ta and Zr/Hf for the lake sediments are identical to those for the local rock but differ from the ratios for the wind-blown dust, and chondrite-normalized rare earth element patterns for the lake sediments are similar to those for the local rock and soil, but differ from those for the distant source. The sediments in Lake Huguang Maar are probably input into the lake through runoff and thus controlled by the hydrology of the lake. Wind-blown dust transported by the Asian winter monsoon from arid North China is only a minor contribution to the sediments.     

AQUAGRID: an extensible platform for collaborative problem solving in groundwater protection

AQUAGRID is the subsurface hydrology computational service of the Sardinian GRIDA3 infrastructure, designed to deliver complex environmental applications via a user-friendly Web portal. The service aims to provide to water professionals integrated modeling tools to solve water resources management problems and aid decision making for contaminated soil and groundwater. In this paper, the AQUAGRID application concept and enabling technologies are illustrated. At the heart of the service are the computational models to simulate complex and large groundwater flow and contaminant transport problems and geochemical speciation. AQUAGRID is built on top of compute-Grid technologies by means of the EnginFrame Grid framework. Distributed data management is provided by the Storage Resource Broker data-Grid middleware. The resulting environment allows end-users to perform groundwater simulations and to visualize and interact with their results, using graphs, 3D images and annotated maps. The problem solving capability of the platform is demonstrated using the results of two case studies deployed.     

岩溶地区冲孔灌注桩完整性检测方法的综合应用

岩溶地区的冲孔灌注桩,因地质条件复杂,其桩身完整性检测的难度较大。通过工程实例,分析探讨各种检测方法的特点、适用范围和局限性,提出各种检测方法综合运用模式,为岩溶区冲孔灌注桩完整性检测的准确性、确保基桩工程质量提供参考。