河南省模拟前兆数据自动汇集系统的设计与开发     

王磊  谢健健  赵辉 《华南地震》2007,27(4):48-53

从技术层面介绍了河南省模拟前兆数据自动汇集系统的设计、开发过程,并进行了效能分析。效能分析表明,该系统设计完善,技术特点较为突出。  相似文献   

基于FTP的数据上报自动传输程序     

朱培育  赵俊香  龚耀  朱佳苗  施俊杰  秦俊高  黄永生 《地震地磁观测与研究》2007,28(4):59-63

为应对地震观测数据量激增以及发报时间要求日趋紧张的情况,作者开发了一个基于Ftp,具有较高效率的上报数据自动传输程序.本文就程序的开发目的、实现方法和实际应用效果进行阐述.  相似文献   

垂直流人工湿地填料的淤堵机理初探   总被引：11，自引：1，他引：11       下载免费PDF全文

童巍  朱伟  阮爱东 《湖泊科学》2007,19(1):25-31

应用人工湿地技术处理污水时,填料的淤堵往往是制约其处理功效和使用寿命的主要因素.本研究采用垂直流人工湿地单元模型,通过测定填料有效孔隙率与截留SS总量、COD降解量、生物膜的增长量之间的关系,初步探讨填料淤堵机理.结果表明:进水中悬浮颗粒全部为无机颗粒的系统较进水中全部为溶解态污染物质的系统更易造成淤堵,进水中全部为溶解态污染物的系统至实验结束时未出现淤堵现象.淤堵发生后,填料上层的渗透系数明显低于中下层,表明淤堵主要发生在填料上层部分;截留的不可生物降解无机SS、被截留但未被降解的有机SS、生物膜的生长及老化脱落、以及被上述物质吸附的水是导致淤堵的主要原因.淤堵发生后,湿地日污染物去除总量降低,湿地功效受到影响.  相似文献   

云南星云湖大街河口湖滨湿地修复及净化效果   总被引：3，自引：2，他引：3       下载免费PDF全文

李荫玺  胡耀辉  王云华  祁云宽  唐芳  刘俊  杨林 《湖泊科学》2007,19(3):283-288

星云湖入湖污染物负荷量80%来自面源,而河道是输送污染物的主要通道,为了削减入湖污染物,在大街河口末端修复湖滨湿地4.5 hm2,恢复湖湾沉水植物28.8 hm2,对表流湿地及沉水植物的净化效果进行了试验研究.研究结果表明,由于水生植物庞大的表面积吸附、分解和吸收作用、水质净化水质效果十分明显,净化大街河水317.8×104 m3/a,SS、BOD5、CODMn、TN、TP的去除率分别为82.8%、60.1%、52.8%、49.2%、40.7%.河口湖滨湿地的修复不仅净化了水质,而且改善了河湾景观,恢复了湖泊生物多样性.  相似文献   

基于SWAT2000模型的流域氮营养素环境自净效率模拟--以杭埠-丰乐河流域为例   总被引：8，自引：0，他引：8  

胡连伍  王学军  罗定贵  蒋颖 《地理与地理信息科学》2006,22(2):35-38

应用分布式非点源污染模型SWAT 2000对杭埠—丰乐河流域的水文、泥沙以及水质模拟进行校核,验证了模型在该研究区的适用性。对基于SWAT模型的氮营养素自净效率计算方法进行完善,即考虑流域本底情况,计算全流域和河流的自净效率分别为0.991和0.005;由于计算时无法考虑地下水的贡献和无法统计NH4 -N和NO2--N的入河负荷,实际河流氮营养素自净效率要高于计算值。给出流域氮营养素自净效率的月际变化特征;进一步计算各个亚流域的环境自净效率,获得其空间分布特征。  相似文献   

Modelling transport phenomena in a flotation de-inking column: Focus on gas flow,pulp and froth retention time     

D. Beneventi  X. Rousset  E. Zeno 《International Journal of Mineral Processing》2006

A laboratory flotation column using Venturi aerators and a vacuum system to remove froth was used to investigate the contribution of gas flow, pulp flow, cell volume and froth retention time on the ink removal efficiency and on cellulose fibres and mineral fillers loss. The increase in the gas flow from 4 to 8 L/min gave a general rise of particle transport from the pulp slurry to the froth with an ensuing strong increase in ink removal, from 75% to 85%, and water and total loss, from 10% to 40% and 15% to 30%, respectively. Whereas, the increase of the cell volume from 14 to 24 L improved ink removal from 72% to 80% without considerably affecting flotation loss. The rise of the froth retention time in the flotation cell from 5 to 20 s before removal gave a general decrease in the flotation loss from 20% to 11% without a corresponding decrease in ink removal. This trend was interpreted as reflecting poor ink drainage through the froth. The increase of both pulp and froth retention time in the flotation cell appeared as the most favourable way to improve ink flotation selectivity. A mathematical model, describing particle removal during flotation in terms of true flotation, entrainment and drainage, was proposed and used to fit experimental data.  相似文献   

高效钻探技术是加速“危机矿山接替资源勘探规划”实施的最有效手段          下载免费PDF全文

张永勤 《探矿工程》2006,33(1):6-8

论述了矿产资源对我国经济建设及社会发展的重要意义、我国矿产资源面临的严峻形势以及实施“危机矿山接替资源勘探规划”的必要性。强调了高效地质取样钻探技术在实施“规划”中不可替代的重要作用，提出了加速“规划”实施和降低施工成本的高效钻探技术。  相似文献   

Distribution and dynamics of large woody debris and organic matter in a low-energy meandering stream   总被引：1，自引：1，他引：1  

Melinda D. Daniels   《Geomorphology》2006,77(3-4):286

This field-based study, using a combination of bed sediment sampling and large woody debris (LWD) tracking, explores the storage of organic matter and mobility of LWD in Poplar Creek, a low-energy meandering river that contains a diverse arrangement of large woody debris (LWD). This research addresses the following questions: 1) Does LWD influence the spatial pattern of the storage of benthic organic matter in meander bends? 2) How mobile is the LWD in low-gradient meandering systems? 3) Do characteristics of LWD such as length/bankfull channel width ratio, affect movement? Based on detailed sampling of sediment and LWD monitoring, this study provides a detailed representation of the influence of LWD on the storage of benthic organic matter in meander bends, as well as a detailed documentation of the mobility of LWD in the study reach. This study has demonstrated that: 1) LWD strongly influences patterns of storage of benthic organic matter in low-gradient meander bends; 2) removal of LWD from meander bends in low-gradient systems can substantially reduce the storage of benthic organic matter; and 3) the LWD within the study reach at Poplar Creek is highly mobile. The high mobility of LWD, observed in this study, contrasts with the rates observed in high-gradient systems and suggests that LWD-influenced patterns of storage of organic matter are temporally variable and that storage of benthic organic matter occurs in pulses, interspersed with transport, that are keyed to the mobility of LWD. Although LWD may exert an equally significant control over patterns of storage of organic matter in high- and low-gradient systems, the differences in the mobility rates of LWD suggest a fundamental difference in the dynamics of LWD-mediated organic matter between low- and high-gradient systems.  相似文献   

Environmental controls on lambing rate in Patagonia (Argentina): A regional approach     

S.A. Hall  J.M. Paruelo 《Journal of Arid Environments》2006,64(4):713-735

Sheep herd sustainability in Patagonia is limited by reproductive efficiency. As the herds graze on natural vegetation year round, efficiency is constrained by biophysical factors. Our aim was to characterize the environmental controls over effective lambing rate in northwest Patagonia. We related remotely sensed data [surface temperatures and Normal Difference Vegetation Index (NDVI), a surrogate for forage availability] and climatic information to lambing rates. A spatial model explained 63% of the variability in mean lambing rate, based on mean annual NDVI and mean spring surface temperature. The relative inter-annual variability in lambing rates was of similar magnitude to that of annual NDVI. Both lambing rate and NDVI were less variable than climatic factors. Two regional temporal models explained approximately 25% of the variability, based on NDVI values representative of ewes’ nutrition during late gestation and lambing. These models predicted, with 65% and 76% accuracy respectively, the occurrence of better-than-average and worse-than-average yearly lambing rates. These results provided insights into the factors limiting reproduction, and they form the basis for important decision tools for ranch managers. Prediction of lambing rates based on remotely sensed data will reduce the uncertainty and risk in sheep production, increasing the economic sustainability of sheep production.  相似文献   

Assessing desertification   总被引：8，自引：2，他引：8  

S.R. Vern  J.M. Paruelo  M. Oesterheld 《Journal of Arid Environments》2006,66(4):751-763

It is widely recognized that desertification is a serious threat to arid and semiarid environments—which cover 40% of the global land surface and are populated by approximately 1 billion humans. Given the potential relevance of this problem, it is surprising that there is no consensus on the proper way to assess the desertification status of a piece of land. During the last 70 years, conflicting definitions have produced both different assessment methodologies and divergent estimates. Contrary to conceptual issues on desertification, assessment methodologies have not been reviewed comprehensively. Here, we critically review the most common methodologies to assess desertification, and describe their principal consequences on scientific and social arenas.We show that desertification assessment has shifted from simple appraisals of the interannual movement of desert boundaries to complex multivariate field surveys, to practical methodologies based on indicators of ecosystem functioning, such as rain use efficiency. Although often regarded as an evidence of stagnation and failure, these methodologies reflect the progress that desertification ecology has experienced. Future challenges for properly assessing desertification are (1) the lack of reference situations against which actual desertification could be compared, and (2) the difficulties that appear when desertification operates through structural rather than functional ecosystem changes.The coexistence of conflicting definitions and divergent estimates negatively affects societal perception, leading to scepticism and, ultimately, to a delay of eventual solutions. Societies must recognize the progress desertification ecology has made, leave behind concepts that no longer represent current knowledge, grasp the opportunity to better assess the extent and intensity of the problem, and, for the time being, realize that assessing desertification is an unsolved issue.  相似文献