24位地震数据采集器时间格式转换的实现     

孙宏志  孟凡强  李茂林  王淑辉 《东北地震研究》2004,20(2):44-47

应用C语言编写四字节24位采集器时间编码与七字节时间编码间的相互转换程序，并可在单片机上运行。为24位采集器与计算机和外界设备间建立透明时间编码通道。  相似文献   

金矿样品的几种溶样方法   总被引：4，自引：0，他引：4  

杨明荣  孙鹏  牟长贤  石爱萍 《黄金地质》2004,10(1):68-70

通过王水、封闭和烧杯敞口及聚乙烯溶样瓶封闭溶样等方法，对含Au矿样的试样分解、溶样体系及各种溶样方法的对比表明，利用聚乙烯溶样瓶，采用HNO3 NaCl KMnO4 NH4HF2溶样体系，在水浴锅中封闭溶样40min，矿样中的Au即可完全分解。经国家标准物质分析验证，结果与标准值相符。封闭溶样可以避免样品外溢、进溅，使分析结果更准确可靠，降低成本，减少环境污染，适用于大批量样品分析。  相似文献   

多相地貌单元场地勘察中基岩与卵砾石、孤石的鉴别     

沈振  李成旺  沈飞 《城市地质》2004,16(4):26-28

在多相地貌单元场地勘察中，基岩与卵砾石的鉴别难度较大。应利用初步感性认识、钻进状态、岩样特征等多手段对基岩与卵砾石进行判别，以提高判别率。  相似文献   

贵州百花湖分层晚期有机质降解过程与溶解N₂O循环   总被引：7，自引：0，他引：7       下载免费PDF全文

王仕禄  刘丛强  万国江  陶发祥  李军  朱兆洲  吕迎春 《第四纪研究》2004,24(5):569-577

百花湖是一个具有季节性分层的富营养小型湖泊,在秋季湖水倒转期经常发生水质恶化事件,碳氮循环出现异常。文章研究特选择在秋初,湖泊分层开始消失时,测定了湖水中不同深度的N₂O,CH₄,CO₂,有机和无机碳同位素以及其他化学参数变化。结果发现:采样时百花湖在约6m和16m深度附近出现了两个温度不连续层(SDL和PDL),并影响到有机颗粒的沉降和分解。相对而言,有较多的有机质在这两个层内发生降解,但降解的途径有所不同,上部主要是有氧降解,下部则主要是无氧降解过程。N₂O的产生和消耗与有机质的降解过程完全对应:PDL层以上,ΔN₂O与AOU的线性关系反映了N₂O主要形成于硝化作用;PDL层以下反硝化作用导致N₂O严重不饱和;PDL内位于硝化作用和反硝化作用过渡带的N₂O峰,显然是硝化与反硝化联合作用的结果。PDL层内较大的CH₄浓度变化梯度,说明嗜甲烷细菌可能通过氧化NH+4贡献了部分N₂O。百花湖秋、冬季表层湖水N₂O都是过饱和的,都是大气N₂O的源,依据分子扩散模型计算湖泊N₂O的释放通量在12～14μmol/m·day之间,秋、冬季没有明显的差别。秋季底层湖水的反硝化作用是湖泊N₂O的汇,其消耗通量与表层的释放通量基本相当。  相似文献   

华南石炭纪岩关-大塘界线期牙形石地层分带   总被引：4，自引：0，他引：4  

田树刚  M.科恩 《地质通报》2004,23(8):737-749

系统采集不同沉积相区和连续沉积的剖面，即浅海台地相广西柳江龙殿山剖面、台缘缓坡相云南施甸鱼硐剖面和台内盆地相广西柳州碰冲剖面，运用数理统计方法，研究了华南岩关一大塘界线过渡期牙形石的产出丰度和相分布，在恢复生物演化序列的基础上，对各剖面首先详细分带，再进一步综合成系统的5个牙形石带，即Gnathodus typicus—G．cuneiformis带、Gnathodus typicus—Protognathodus cordiformis带、Scaliognathus anchoralis—Gnathodus pseu-dosemiglaber带、Gnathodus praebilineatus带和Paragnathodus horrtopunctatus带。以生物系统发生为标准，严格限定各带的界线，并与北美、西欧同期地层进行精确对比，为建立杜内阶一维宪阶界线的全球层型(GSSP)提供可靠依据。  相似文献   

从等值线图形获取DAT和GRD格式的数据文件   总被引：2，自引：0，他引：2  

王宜芳 《现代测绘》2004,27(2):45-46

在盆地模拟研究工作中，需要处理大量的地质数据和地质图件，一方面，随时需要把各种数据变为可视的图形；另一方面，还时常需要从图形中得到研究中所必需的数据，例如，由构造图得到研究区域的深度数据文件。本文介绍一种从等值线图形获取DAT格式和网格化GRD格式的数据文件的方法。  相似文献   

From Chicago to L.A. and Back Again: A Chicago‐Inspired Quantitative Analysis of Income Distribution in Montreal*     

Richard Shearmur  Mathieu Charron 《The Professional geographer》2004,56(1):109-126

In a recent issue of Urban Geography (2001) , a number of key players in the 1960s and 1970s school of quantitative urban geography (called Chicago II in this article) set out some of the approach's key methodological premises and assessed its influence in the wider arena of urban studies. At about the same time, the 1920s and 1930s Chicago School of urban sociology (called the Chicago School in this article) was being reassessed in France ( Huet 2000 ), and deconstructed in Los Angeles ( Dear 2001 ). In this article, we outline a selection of basic models of urban space proposed by the Chicago School and further elaborated by Chicago II. We then consider certain aspects of three important critiques: humanist/aesthetic, Marxist, and postmodern. We argue that none of these invalidates the Chicago II approach to the study of urban areas, and we demonstrate its resilience and usefulness by way of the empirical example of Montreal. Though the results are of interest in their own right, the principal purpose of the analysis is to illustrate the type of insight that a structured quantitative approach provides and the way this approach rests on a theoretical understanding of processes at work in cities. We conclude by arguing that the humanist and Marxist critiques shed important light upon the possibilities and limits of the Chicago II approach, but that the postmodern claim that the spatial development of urban areas is not structured by at least some general processes is inaccurate.  相似文献   

关于数字化记录中前兆信号的分析   总被引：1，自引：0，他引：1  

王亮 《地震地磁观测与研究》2005,(Z1)

介绍了如何用MATLAB工具软件—小波分析的基本理论对数字信号进行数字滤波,着重分析和研究了呼和浩特地震台形变观测资料出现各种信号,提出了小波分析理论对台站实际工作的重要性。  相似文献   

Mercury and methylmercury biogeochemistry in a thawing permafrost wetland complex,Northwest Territories,Canada          下载免费PDF全文

J. Gordon  W. Quinton  B. A. Branfireun  D. Olefeldt 《水文研究》2016,30(20):3627-3638

In arctic and sub‐arctic environments, mercury (Hg), more specifically toxic methylmercury (MeHg), is of growing concern to local communities because of its accumulation in fish. In these regions, there is particular interest in the potential mobilization of atmospherically deposited Hg sequestered in permafrost that is thawing at unprecedented rates. Permafrost thaw and the resulting ground surface subsidence transforms forested peat plateaus into treeless and permafrost‐free thermokarst wetlands where inorganic Hg released from the thawed permafrost and draining from the surrounding peat plateaus may be transformed to MeHg. This study begins to characterize the spatial distribution of MeHg in a peat plateau–thermokarst wetland complex, a feature that prevails throughout the wetland‐dominated southern margin of thawing discontinuous permafrost in Canada's Northwest Territories. We measured pore water total Hg, MeHg, dissolved organic matter characteristics and general water chemistry parameters to evaluate the role of permafrost thaw on the pattern of water chemistry. A gradient in vegetation composition, water chemistry and dissolved organic matter characteristics followed a toposequence from the ombrotrophic bogs near the crest of the complex to poor fens at its downslope margins. We found that pore waters in poor fens contained elevated levels of MeHg, and the water draining from these features had dissolved MeHg concentrations 4.5 to 14.5 times higher than the water draining from the bogs. It was determined through analysis of historical aerial images that the poor fens in the toposequence had formed relatively recently (early 1970s) as a result of permafrost thaw. Differences between the fens and bogs are likely to be a result of their differences in groundwater function, and this suggests that permafrost thaw in this landscape can result in hotspots for Hg methylation that are hydrologically connected to downstream ecosystems. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

Elastic models for nonlinear response of rigid passive piles     

W. D. Guo 《国际地质力学数值与分析法杂志》2014,38(18):1969-1989

Recent study indicates that the response of rigid passive piles is dominated by elastic pile–soil interaction and may be estimated using theory for lateral piles. The difference lies in that passive piles normally are associated with a large scatter of the ratio of maximum bending moment over maximum shear force and induce a limiting pressure that is ~1/3 that on laterally loaded piles. This disparity prompts this study. This paper proposes pressure‐based pile–soil models and develops their associated solutions to capture response of rigid piles subjected to soil movement. The impact of soil movement was encapsulated into a power‐law distributed loading over a sliding depth, and load transfer model was adopted to mimic the pile–soil interaction. The solutions are presented in explicit expressions and can be readily obtained. They are capable of capturing responses of model piles in a sliding soil owing to the impact of sliding depth and relative strength between sliding and stable layer on limiting force prior to ultimate state. In comparison with available solutions for ultimate state, this study reveals the 1/3 limiting pressure (of the active piles) on passive piles was induced by elastic interaction. The current models employing distributed pressure for moving soil are more pertinent to passive piles (rather than plastic soil flow). An example calculation against instrumented model piles is provided, which demonstrates the accuracy of the current solutions for design slope stabilising piles. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献