科尔沁沙质草甸土壤微生物数量的垂直分布及季节动态

通过对中国农牧交错带科尔沁沙质草甸土壤微生物数量的垂直分布及其季节动态的研究分析表明:(1)微生物总数、细菌和放线菌数量均表现出与降雨量同步的季节动态,即6月份较5月份有所减少,7月份增至最多,7月份以后微生物数量逐渐下降,真菌则表现出从5月份到8月份一直增加,9月份开始回落;(2)土壤微生物具有明显的垂直分布差异.细菌和放线菌的垂直分布表现出随土壤深度增加逐渐减少的趋势,真菌数量表层最高,20 cm以下变化不够规律;(3)土壤微生物的层化比率均大于2(5月份放线菌除外);(4)不同土壤生态因子对微生物的影响不同,相同因子对不同微生物类群的影响也不相同.细菌受水分影响较大,真菌与地温的变化趋势相近,放线菌与水热条件的共同作用有关.土壤养分(有机碳和全氮)与微生物数量呈显著的正相关.     

嫩江流域近45年来径流演变规律研究

采用随机水文学方法对嫩江流域1956~2000年的年径流量序列演变特征进行分析。结果表明,嫩江流域径流的水文周期是32a,整体而言,45a径流序列不存在明显的趋势性。此外,对嫩江流域用水性消耗程度进行分析。结果表明,人类用水性消耗量对流域水循环整体影响程度为5%,但是在流域内部影响程度存在较大差异。洮儿河子流域影响因子达到16%,反映该地区人类取用水消耗量较大。从年际分析,整个流域在70年代的影响因子要高于其它年段,呈现出越是枯水年段人类用水影响程度越大的现象。     

Tectonic Features of the M_S8.0 Wenchuan Earthquake and Its Aftershocks

The M8.0 Wenchuan earthquake occurred on the Longmenshan fault zone. Based on field investigation of the surface rupture and focal mechanism study of the aftershocks, we discuss the geological relationship of the main, secondary and triggered ruptures. The main rupture is about 200km long and can be divided into the south part and the north part. The south part consists of two parallel fault zones characterized by reverse faulting, with several parallel secondary ruptures on the hanging wall of the main fault, and the north part is a single main fault zone characterized by lateral strike-slip and reverse faulting. Compared to a 300km long aftershock distribution, the surface rupture only occupies 200km, and the remaining 100km on the northeast of the main rupture was triggered by aftershocks. Study on the ruptures of this earthquake will be useful for studying the earthquake risk evolution on the Longmenshan fault system.     

Estimation of strong seismic ground motion for engineering use in Perth Western Australia

Probabilistic seismic hazard analysis (PSHA) was performed to determine two alternate magnitude-distance combinations for the 475 yr event, and the worst-case scenario event in Perth, Western Australia. Regional strong ground motion (SGM) time histories on rock sites are used to modify an eastern North America (ENA) seismic model to suit southwest Western Australian (SWWA) conditions. This model is then used to stochastically simulate a set of 475 yr design events and a set of worst-case scenario event for rock sites in the Perth metropolitan area (PMA). The simulated time histories are then used as input to typical soft soil sites in the PMA to estimate surface ground motions. The spectral accelerations of the ground motions on rock and soil sites are calculated and compared with the corresponding design spectra defined in current and previous Australian earthquake loading code. Discussions of the adequacy of the code spectra and the differences to ours, along with implications on structural response and damage are made.     

汶川8.0级地震水坝震害调查

“5．12”汶川地震中水坝损毁严重,造成了巨大的经济损失。震后对69座溃坝险情和310座高危险情水库水坝进行了系统的调查,典型震害现象包括坝体裂缝、塌陷、滑坡、渗漏、启闭设施损坏和其他附属设施的损毁等。文中给出了不同烈度区的水坝震害分布,并对地震中水坝的震害现象做了初步总结和分析。     

利用正交多项式对三维地震资料拟合算法的研究

目前在地震勘探中经常采用的拟合方法多是二维的,本文利用正交多项式的性质以及地震资料的相干性对地震资料进行三维拟合.该方法充分利用了三维地震资料,提高了处理效率.     

Process and mechanism for oil and gas accumulation,adjustment and reconstruction in Puguang Gas Field,Northeast Sichuan Basin,China

With the discoveries of a series of large gas fields in the northeast of Sichuan Basin, such as Puguang and Longgang gas fields, the formation mechanism of the gas reservoir containing high H2S in the ancient marine carbonate formation in superposition-basin becomes a hot topic in the field of petroleum geology. Based on the structure inversion, numerical simulation, and geochemical research, we show at least two intervals of fluid transfer in Puguang paleo-oil reservoir, one in the forepart of late Indo-Ch...     

地震专用数字钟的研制及试运行结果

本文详细介绍了地震专用数字钟的研制及试运行结果,阐述了数字钟的工作原理,使用方法等,对指导台站使用数字钟具有帮助作用。     

波前构建法中的网格点定位(英文)

针对波前构建法中非规则的波前四边形网格与规则的矩形网格节点之间的相对定位问题,对比分析了在计算机图形学中常用的四种网格定位方法(叉乘判断法、夹角之和检验法、射线法(交点计数检验法)以及符号比较法)在波前构建法中的具体实现问题,通过对定位方法稳健性分析及计算实例表明,矢量叉乘判断法在实现规则的矩形网格节点与非规则的波前四边形网格相对定位研究中,其稳健性和计算效率足最高的,从而为下一步做偏移或者反偏移提供了精确的网格点属性值.     

水平-摇摆耦合振动波阻板主动隔振三维分析

为研究三维地基中波阻板（简称WIB）的隔振效果,建立了以薄层法基本解答作为格林函数的半解析边界单元法。对水平-摇摆耦合激振作用下WIB隔振系统的主动隔振进行了计算,详细分析了WIB参数对隔振效果的影响。研究表明,WIB可以有效地隔振;增加WIB的厚度、提高WIB的弹性模量、减小WIB 的埋深可以有效提高隔振效果,而增加WIB的直径可以显著降低WIB范围内地表位移振幅,但对WIB范围外的地表位移影响较为复杂。