全球不同地区强震与地球自转之间的关系分析

对全球及一些地区地震在地球自转速率长周期变化的加速和减速段里年发生次数进行了分析,得到的结果表明,就全球地震而言,减速期7级以上地震年发生次数似乎略高于加速期,8级以上地震年发生次数似乎相当,没有明显差异,8.5级以上地震年发生次数似乎比加速期里高.太平洋东带和太平洋北带的地震,在减速期的年发生次数似乎一致地比加速期略...     

High-resolution monitoring of nitrate variations in a typical subterranean karst stream, Chongqing, China

Globally, it is possible that up to 25% of the world’s population depends on karst water supplies. In karst areas, a high degree of groundwater and surface water linkage often results in the direct recharge of groundwater with polluted run-off following rainfall. In order to reveal the hydrochemical variations after rainfall, especially real-time variation of pollutants, high-resolution auto-monitoring techniques were used at the outlet of Qingmuguan subterranean stream (QSS), which is influenced by agricultural activities. In addition to rainfall, high-resolution measurements of pH, water level, electrical conductivity (Ec) and NO₃ ⁻ concentration were recorded in the monsoon season and fertilizer application period using a data logger with time intervals of 15 min. In the six observed rainfall events, the pH value was mainly controlled by acidic rainfall inputs. The pH showed sharp decline after the rainfall event, and then increased. The Ec was impacted by the rainfall chemistry, dilution effect of rainfall and agricultural wastewater. NO₃ ⁻ derived from agricultural activities was less impacted by rain chemistry; and its variations were mainly affected by the dilution effect of rainfall and agricultural wastewater. Under the influences of the R1 rainfall, the rapid changes of Ec and NO₃ ⁻ were opposite in direction. As the rain continued, both the Ec and NO₃ ⁻ rapidly changed in synchronization within the shortest period of 5 h and the longest of 27 h because of the impact of the agricultural wastewater. The groundwater quality changed due to the influx of agricultural wastewater over the entire monitoring period. According to the National Groundwater Quality Standard, People’s Republic of China (GB/T14848-9), the groundwater quality of the QSS moved through the following grades during the monitoring period: Grade III → Grade IV → Grade V → Grade IV → Grade V → Grade IV → Grade V → Grade IV → Grade III. Traditional sampling methods did not reveal accurate hydrochemistry changes of the QSS, and even generated misleading results. Consequently, the high-resolution auto-monitoring technique is necessary for the future protection and sustainable use of karst aquifer in Southwest China.     

Comparisons of internal solitary wave and surface wave actions on marine structures and their responses

In this paper, a time-domain numerical model is established for computing the action of internal solitary wave on marine structures and structure motion responses. For a cylindrical structure, its side and bottom are discretized by pole and surface elements, respectively. The drag and inertial forces in the perpendicular direction of the structure are computed by the Morison equation from the pole elements, and the Froude–Krylov force in the axial direction of the structure due to internal wave motion is computed by integration of the dynamic pressure over the surface elements. The catenary theory is used to analyze the reaction force due to mooring lines, and the motion equation of the marine structure is solved by the fourth-order Runge–Kutta method in the time domain. The model is used to calculate the interaction of the internal solitary wave with a Spar platform with mooring system, and the surface wave action with the platform has also been computed by a frequency-domain boundary element method for comparison. Through the comparison based on a practical internal wave and surface wave states, it can be concluded that the internal wave force on the structure is only 9% of the one due to surface waves. However, the motion response due to the internal wave is much greater than the one due to the surface waves. It shows that the low-frequency effect of internal solitary waves is a great threat to the safety of marine structures.     

地学现象的分维与标度关系——以中国大陆山系为例

分形理论产生以后,已经在许多领域里取得了较为广泛的应用,但是在分形维数的计算方面仍存在一定的问题,最根本的问题之一是大量相关研究往往忽略了标度问题的影响,而将计算出的分维结果随意比较。本文则是以中国大陆山系为例,对地学现象的分维与标度的关系进行了研究,得出:(1)中国大陆山系的分形性质是客观存在的,其分形性质是不以测算标度而出现变化的,是始终存在的;(2)虽然在不同的测算标度下,中国大陆山系的分形性质始终是客观存在的,但是随着测算标度范围的变化,中国大陆山系的分维也会相应地出现一定的变化,即中国大陆山系客观存在的分形性质是绝对的,而分维则是一个相对的值,是随着测算标度而出现变化的;(3)分维不仅随着测算标度的变化而出现一定的变化,而且,分维是测算平均标度的函数,即D=f(r)(式中:r为测算平均标度,D为分维)关系成立;(4)因为分维值会随着不同标度范围的变化而出现相应的变化,所以,如果要进行分维之间的比较,则应选择相同的标度范围和标度值点。     

安塞油田可视化决策系统研究

 利用安塞油田可视化决策系统,将基础勘察数据油田基本图件和油井数据有效的管理起来,可作统计分析、档案更新、数据查询。这不仅对属性数据可采用数据库管理,而且通过空间数据对属性数据的空间分布特征进行综合分析,实现属性数据、空间数据可视化     

线阵CCD数据的高速采集与存储

在各种高精度线阵CCD应用系统中，需要对像元输出信号进行快速采样、存储及数据处理。CCD数据采集的采样速率不仅与A／D转换器的转换速率等因素有关，同时还与数据传送方式密切相关。以高精度线阵CCD TCD1501D和高速A／D转换器TLC5510为例．详细分析了CCD和A／D转换器的工作时序，采用CPLD设计方法，将CCD的输出信号进行高速A／D转换，并将结果直接存入存储器中。     

搬迁企业原址场地土壤挥发性有机物污染特征——以北京某搬迁化工厂为例

搬迁企业原址场地可能受原生产生活遗留有毒有害物质的污染,因此,在原场地再利用之前必须对其进行污染调查.对北京市某化工厂搬迁场地进行土壤污染初步调查,以超建设用地二类用地的筛选值或管制值来表征污染物超过土壤背景值的程度.初步污染调查结果表明,该场地土壤中苯、甲苯、氯苯、四氯化碳和氯仿浓度超标.其中苯、四氯化碳和氯仿的最大浓度分别超筛选值的32.5倍、59倍和151.2倍,且都超管制值,属于重度污染;甲苯最大浓度超筛选值(等于管制值)3.23倍,属于中—重度污染;氯苯略微超过筛选值,属于轻度污染,超标土样均来自同一钻孔AD56.场地污染特征,平面上呈点状分布,垂向上污染集中在约4 m深处的弱透水层,与地层岩性关系密切.经场地重点区域初步污染调查判定为污染地块,需进行详细调查和风险评估.     

An Adaptive Noise Reduction Method for NDVI Time Series Data Based on S–G Filtering and Wavelet Analysis

In order to reduce the noise in advanced very high-resolution radiometer global inventory modeling and mapping studies normalized difference vegetation index (NDVI) version 3g time series data, we propose an adaptive noise reduction method based on the Savitzky–Golay filter and wavelet analysis and on curve-fitting and spectrum analysis. The noise reduction effect was analyzed and evaluated. Studies have shown that the denoising of data using asymmetric Gaussian and double logistic curve-fitting methods results in the loss of details of the NDVI changes and is not conducive to the extraction of vegetation phenotypic characteristics. The wavelet function, wavelet decomposition layer number, and the threshold determination method have a large influence on the noise reduction effect, and the adaptive method has high noise reduction efficiency and effectively reduces the noise in the NDVI data. The proposed method does not require the determination of the smoothing window size and threshold for each year, which represents an advantage for processing large amounts of data.     

Investigation on Snow Characteristics and Their Distribution in China

The background, scientific objective, investigation contents and scheme of project “Investigation on snow characteristics and their distribution in China” was introduced in this paper. The general objective of the investigation is to build comprehensive and systematic database of snow characteristics in China, at the service of providing data for the climate change, water resource and snow disaster studies. The investigation will be performed on the three fields including the compilation of historical data, in situ measurement of snow characteristics in the typical regions, and investigation of snow characteristics using remote sensing methods. For the compilation of historical data, the historical snow data from the meteorological stations and research institutes will be firstly collected, and then they will be compiled based on a standard rule. In situ observation will be performed at point, line and area-scale on the typical regions which include Northeast region, Xinjiang Degion, and Qinghai-Tibet Plateau. The observation content will contain snow depth, snow density, snow water equivalent, snow particle shape, hardness of snowpack surface, liquid water content, grain size, snow temperature, snow/soil temperature, dielectric constant, and some chemical parameters. These snow characteristics are the priority information used for the modification of retrieval algorithm on snow parameters. Remote sensing methods will be used to build long-time series of snow cover, snow albedo and snow water equivalent datasets based on these modified algorithms. Finally, the snow characteristics from both in situ and remote sensing investigation will be used to classify snow types in China, and produce distribution maps of snow characteristic and other thematic maps.