Spatial distribution of large-scale landslides induced by the 5.12 Wenchuan Earthquake

The 5.12 Wenchuan Earthquake in 2008 induced hundreds of large-scale landslides. This paper systematically analyzes 112 large-scale landslides (surface area > 50000 m2), which were identified by interpretation of remote sensing imagery and field investigations. The analysis suggests that the distribution of large-scale landslides is affected by the following four factors: (a) distance effect: 80% of studied large-scale landslides are located within a distance of 5 km from the seismic faults. The farther the distance to the faults, the lower the number of large-scale landslides; (b) locked segment effect: the large-scale landslides are mainly located in five concentration zones closely related with the crossing, staggering and transfer sections between one seismic fault section and the next one, as well as the end of the NE fault section. The zone with the highest concentration was the Hongbai-Chaping segment, where a great number of large-scale landslides including the two largest landslides were located. The second highest concentration of large-scale landslides was observed in the Nanba-Donghekou segment at the end of NE fault, where the Donghekou landslide and the Woqian landslide occurred; (c) Hanging wall effect: about 70% of the large-scale landslides occurred on the hanging wall of the seismic faults; and (d) direction effect: in valleys perpendicular to the seismic faults, the density of large-scale landslides on the slopes facing the seismic wave is obviously higher than that on the slopes dipping in the same direction as the direction of propagation of the seismic wave. Meanwhile, it is found that the sliding and moving directions of large-scale landslides are related to the staggering direction of the faults in each section. In Qingchuan County where the main fault activity was horizontal twisting and staggering, a considerable number of landslides showed the feature of sliding and moving in NE direction which coincides with the staggering direction of the seismic faults.     

秦岭中部山地落叶阔叶林超级垂直带的发现与意义

山地垂直带谱是气候和植被水平地带变化和更替的缩影,垂直带的带幅、带间过渡方式、带内结构和垂直带组合方式都表现出高度的异质性和复杂性。本文发现在中国南北过渡带中部太白山发育了世界上最宽的山地垂直带——山地落叶阔叶林垂直带。该垂直带从基带到典型垂直带再到先锋性垂直带皆为山地落叶阔叶林,3种本来可以独立存在的垂直带,连续分布形成了包含3个栎林亚带、2个桦林亚带的“三层五亚带”超级垂直带,远远超过正常情况下山地垂直带1000 m的阈值,且其上限达到了海拔2800 m。它的形成与秦岭所处的过渡性地理位置、秦岭中部垂直带谱的完整性、丰富的落叶木本植物种群及其形成的强大群落竞争优势等因素紧密相关。超级垂直带的发现有多方面的意义：它是中国南北过渡带又一重要的标志性自然地理特征;它表明山地垂直带在特殊的山地环境中可以具有非常复杂的内部结构和宽大带幅,这扩展了我们对山地垂直带谱结构及机理认识的广度,对于创建山地垂直带谱结构理论具有十分重要的意义;超级垂直带的发现,也说明中国南北过渡带还有很多科学内容有待我们去探索和发现,希望本文能起到抛砖引玉的作用,引起学界对超级垂直带形成的气候和生物多样性因素、地理过渡带的结构和生态效应等重大问题进行深入研究。     

在庆祝山东省地质科学实验研究院建院50周年大会上的讲话

今天,我们在这里隆重集会,庆祝省地科院建院50周年.首先,我代表山东省国土资源厅,向全院广大干部职工和离退休老同志,表示崇高的敬意!向长期以来关心支持我省地质工作的各级领导和社会各界人士,表示衷心的感谢!     

Estimation of groundwater residence time and recession rate in watershed of the Loess Plateau

Groundwater residence time is an important indicator of hydrological cycle and essential for water resources development and utilization. In this paper, groundwater residence time in non-flood season, flood season and water year has been determined from daily streamflow hydrograph of ten hydrological stations in Wudinghe River Basin located in the middle reaches of the Yellow River Basin. Results have showed that: baseflow recession constant in Wudinghe River Basin ranges from 0.72 to 0.94 with a larger recession rate in flood season than that in non-flood season. Spatially, the recession rate of baseflow in loess area is the biggest, but is the smallest in the sandy area. The half-residence time of groundwater varies from 1.8 to 45.5 days while overall residence time of groundwater is between 34 and 342 days in different sub-basins of the Wudinghe River Basin. The annual average overall residence time of groundwater decreases from 117 days in the upper reaches to 73 days in the lower reaches.     

地幔对流与岩石层板块的相互耦合及影响──（Ⅱ）地幔混合对流理论及其应用

观测到的板块运动包含两种能量分布几乎相等的运动形态：极型场和环型场．纯粹的由热驱动的地幔自由对流不能预期和解释环型运动的产生．本文提出地幔混合对流理论,既考虑了热驱动的自由对流,也考虑了由板块自身激发的强迫对流．根据板块处于动力学平衡状态的观测事实,建立了相应的模型．数值结果表明,根据混合对流模型所预期的板块速度场,既能产生极型场,也能产生环型场,而且在空间分布特征及功率谱分布上与观测资料符合相当好．地幔物质的上升流动基本和洋脊对应,而下降流动和俯冲带对应．     

Discovery of 13 New Variable Stars in the Field of the Open Cluster NGC 2168 （M35）

A wide-field time-series CCD photometric survey of variable stars in the field of the open cluster NGC 2168 was carried out using the BATC Schmidt telescope. In total 13 new variable stars are discovered with three W UMa systems, one EA type and two EB type eclipsing binaries (one of them could be a W UMa system), and seven pulsating stars including three candidates of δScuti stars.     

萨拉乌苏河流域150 ka BP以来的粒度旋回

萨拉乌苏河流域米浪沟湾地层剖面150kaBP以来古流动砂丘砂与河湖相和古土壤在粒度上具有多次显著的粗细韵律交替变化，粒度参数-Mz、σ、Sk、Kg和SC/D亦随之响应为多波动峰谷交替的态势，同时，粒度特征值-φ5、φ16φ、φ25、φ50、φ84、φ9相应地表现为非常有节奏地跳动，据此，将米浪沟湾剖面划分为27个粒度粗细沉积旋回，并认为其是150kaBP以来在东亚冬夏古代季风交替影响下沙漠演变的一个颇为完整的气候-地质过程记录。     

2009年夏季极区电离层加热实验观测研究

2009年夏季,中国在挪威特罗姆瑟(Tromsφ)利用非相干散射雷达进行电离层加热实验。实验中发现了处在150km附近的小范围温度增强事件和150—400km之间的大范围温度增强事件。前者的相对增幅明显,后者的绝对增量更大。对这两类加热事件来说,温度增量百分比均随加热功率的增加线性增长,但对比两类加热事件来看,增长速度随加热频率增大而减小。加热效应存在显著的二维分布特征,加热最强方向处在场向附近。加热效应受加热天线波束指向与地磁场的夹角影响明显,随夹角增大温度增强效应减弱。     

External calibrator in global signal experiment for detection of the epoch of reionization

We present a conceptual design study of external calibrators in the 21 cm experiment towards detecting the globally averaged radiation of the epoch of reionization(EoR). Employment of external calibrator instead of internal calibrator commonly used in current EoR experiments allows removing instrumental effects such as beam pattern, receiver gain and instability of the system if the conventional three-position switch measurements are implemented in a short time interval. Furthermore, in the new design the antenna system is placed in an underground anechoic chamber with an open/closing ceiling to maximally reduce the environmental effect such as RFI and ground radiation/reflection. It appears that three of the four external calibrators proposed in this paper, including two indoor artificial transmitters and one outdoor celestial radiation(the Galactic polarization), fail to meet our purpose. Diurnal motion of the Galactic diffuse emission turns out to be the most probable source as an external calibrator, for which we have discussed the observational strategy and the algorithm of extracting the EoR signal.     

WTO渔业补贴谈判焦点问题之探讨

世界贸易组织从2002年启动渔业补贴谈判以来,共进行了近40轮谈判。在谈判期间,渔业补贴的调整范围、规范模式、执行问题以及发展中国家特殊与差别待遇成为成员之间争论的焦点。