小河金矿的细菌预氧化研究   总被引：2，自引：0，他引：2  

郑存江  熊英 《陕西地质》2000,18(2):93-97

陕西旬阳小河金矿的浮选金精矿含砷（２０－２７％）,采用细菌预氧化时较为困难。采用不同方式对有Ｔ．ｆ菌进行驯化,有效地提高了细菌的氧化活性,金的浸出率从０．６％提高到８５．１２％。  相似文献   

Daily reservoir inflow forecasting using artificial neural networks with stopped training approach   总被引：28，自引：0，他引：28  

P. Coulibaly  F. Anctil  B. Bobe 《Journal of Hydrology》2000,230(3-4):244-257

In this paper, an early stopped training approach (STA) is introduced to train multi-layer feed-forward neural networks (FNN) for real-time reservoir inflow forecasting. The proposed method takes advantage of both Levenberg–Marquardt Backpropagation (LMBP) and cross-validation technique to avoid underfitting or overfitting on FNN training and enhances generalization performance. The methodology is assessed using multivariate hydrological time series from Chute-du-Diable hydrosystem in northern Quebec (Canada). The performance of the model is compared to benchmarks from a statistical model and an operational conceptual model. Since the ultimate goal concerns the real-time forecast accuracy, overall the results show that the proposed method is effective for improving prediction accuracy. Moreover it offers an alternative when dynamic adaptive forecasting is desired.  相似文献   

依托GIS二次开发竞赛的大学生双创能力培养模式探讨     

郭明强  黄颖  谢忠  吴亮 《测绘工程》2017,26(12)

大学生是我国双创教育的主要对象,面对严峻的就业形势和激烈的国际竞争环境,在当前大众创业万众创新的时代下,创新创业人才培养是大学对接国家战略的新使命。分析当前大学生双创能力培养中遇到的难题,提出依托GIS二次开发竞赛的大学生双创能力培养模式,探讨竞赛过程中创新能力和创业能力的培养方法,最终达到以GIS二次开发竞赛推动大学生双创教育的目的。  相似文献   

基于3D-GIS的抽水蓄能电厂动态监控与仿真技术研究     

张小冬  吴超  刘学山  汪志强  徐斌  万晟 《测绘工程》2017,26(11)

文中针对抽水蓄能电厂运营信息化建设的需求与现状,依托高精度三维建模技术、设备动态监控、虚拟仿真等技术,对抽水蓄能电厂进行全方位、多视角的精细测绘与三维建模,同时集成电厂现有系统资源,搭建动态监控与仿真一体化平台,解决目前抽水蓄能电厂信息展现不集中、不直观的缺陷,为电厂三维信息化建设提供新型的解决方案。  相似文献   

测绘工程专业数学计算及课程内容优化的探讨   总被引：3，自引：0，他引：3  

余代俊 《四川测绘》2001,24(2):91-94

本文介绍子我校测绘工种专业教学计划中的人才培养目标和培养要求，课程置模块及其特点，并对本专业数门主干课的内容优化作了探讨。  相似文献   

中国地震局地震监测台网技术人员赴德国培训     

中国地震局地震监测台网技术人员培训团 《国际地震动态》2001,(4):12-15

中国地震局地震监测台网技术人员培训团一行15人于2000年9月2－20日赴德国地球科学研究中心（GFZ）和联邦地球科学及自然资源研究院（BGR）进行了培训，在德国的周密安排和中德以方的共同努力下，培训团圆满地完成了预期的培训任务，文章就这次的培训及培训团所了解到的情况作了介绍。  相似文献   

Diatom-environmental relationships in 64 alkaline southeastern Ontario (Canada) lakes: a diatom-based model for water quality reconstructions   总被引：5，自引：0，他引：5  

Euan Reavie  John Smol 《Journal of Paleolimnology》2001,25(1):25-42

Lake eutrophication is a problem in many areas of Ontario, although the history of nutrient enrichment is poorly documented. The aim of this study was to construct a diatom-based transfer function to infer past phosphorus levels in Ontario lakes using paleolimnological analyses. The relationship between diatom assemblages and limnological conditions was explored from a survey of diatoms preserved in the surface sediments of 64 Southern Ontario lakes, spanning a total phosphorus gradient of 0.004 to 0.054 mg L^-1. Over 420 diatom taxa were identified, 98 of which were sufficiently common to be considered in statistical analyses. Canonical correspondence analysis (CCA) determined that pH, ammonium, aluminum, spring total phosphorus (TP), strontium, total nitrogen (TN), maximum depth (MaxZ), chlorophyll a (Chla) and mean depth were significant variables in explaining the variance in the diatom species data. The environmental optima of common diatom taxa for the limnologically important variables (TP, pH, TN, MaxZ, Chla) were calculated using weighted averaging (WA) regression and calibration techniques, and transfer functions were generated. The diatom inference model for spring TP provided a robust reconstructive relationship (r² = 0.637; RMSE = 0.007 mg L^-1; r² _boot = 0.466; RMSE_boot = 0.010 mg L^-1). Other variables, including pH (r² = 0.702; RMSE = 0.208; r² _boot = 0.485; RMSE_boot = 0.234), TN (r² = 0.574; RMSE = 0.0899 mg L^-1; r² _boot = 0.380; RMSE_boot = 0.127 mg L^-1) and MaxZ (r² = 0.554; RMSE = 1.05 m; r² _boot = 0.380; RMSE_boot = 1.490 m), were also strong, indicating that they may also be reconstructed from fossil diatom communities. This study shows that it is possible to reliably infer lakewater TP and other limnological variables in alkaline Southern Ontario lakes using the WA technique. This method has the potential to aid rehabilitation programs, as it can provide water quality managers with the means to estimate pre-enrichment phosphorus concentrations and an indication of the onset and development of nutrient enrichment in a lake.  相似文献   

An expanded weighted-averaging model for inferring past total phosphorus concentrations from diatom assemblages in eutrophic British Columbia (Canada) lakes   总被引：3，自引：0，他引：3  

Euan D. Reavie  Roland I. Hall  John P. Smol 《Journal of Paleolimnology》1995,14(1):49-67

Eighteen lakes were added to a published training set of 46 British Columbia (BC) lakes in order to expand the original range of total phosphorus (TP) concentrations. Canonical correspondence analysis (CCA) was used to analyze the relationship between diatom assemblages and environmental variables. Specific conductivity and [TP] each explained significant (P0.05) directions of variance in the distribution of the diatoms. The relationship between diatom assemblages and [TP] was sufficiently strong to warrant the development of a weighted-averaging (WA) regression and calibration model that can be used to infer past trophic status from fossil diatom assemblages.The relationship between observed and inferred [TP] was not improved by the addition of more eutrophic lakes, however the [TP] range and the number of taxa used in the transfer function are now superior to the original model. Diatom species assemblages changed very little in lakes with TP concentrations greater than 85 µg 1^–1, so we document the development of a model containing lakes with TP85 µg 1^–1. The updated model uses 59 training lakes and covers a range of species optima from 6 to 41.9 µg 1^–1 TP, and a total of 150 diatom taxa.The updated inference model provided a more realistic reconstruction of the anthropogenic history of a highly eutrophic BC lake. The model can now be used to infer past nutrient conditions in other BC lakes in order to assess changes in trophic status.  相似文献   

GIS比赛引领专业人才培养     

黄耀裔  李子蓉  苏建云  陈文成 《测绘与空间地理信息》2016,(2):64-67

GIS作为一种专业技术性强的学科与工具,随着高校转向技术型人才的培养,如何通过GIS比赛引领专业人才培养成为一个值得关注的问题。针对目前国内GIS专业的培养方案、课程设置、GIS比赛方式和比赛内容,在参加GIS比赛后暴露的GIS教学等相关问题,提出将GIS比赛纳入GIS人才培养中以及将GIS比赛纳入课程教学体系,使GIS比赛贯穿于大学教育的始终,让在校大学生在每个阶段参加不同GIS比赛或组别,采取以赛促学、以赛促教来补充GIS的教学内容和形式,提升学生综合素质能力,引领GIS专业人才的培养。  相似文献   

基于评分最优化的模式降水预报订正算法对比   总被引：4，自引：3，他引：1       下载免费PDF全文

吴启树  韩美  刘铭  陈法敬 《应用气象学报》2017,28(3):306-317

使用2013年1月1日-2016年1月7日全国气象站观测资料,应用准对称混合滑动训练期,不改变雨带预报位置和形态,基于模式降水预报订正结果的TS评分最优化及ETS评分最优化,分别设计最优TS评分订正法（OTS）和最优ETS评分订正法（OETS）确定预报日各级降水订正系数,对2014-2015年降水数值预报进行分级订正,并与频率匹配法（FM）对比。结果表明:在24 h累积降水的多个预报时效订正中,无论是对欧洲中期天气预报中心、日本气象厅、美国国家环境预报中心和中国气象局的全球模式降水预报,还是对4个模式的简单多模式平均,OTS和OETS较FM在TS评分和ETS评分等传统降水检验指标上均更优秀,其中OTS在所有时效均能提高模式降水预报质量,为三者最优。在概率空间的稳定公平误差评分方面,OTS在各时效、各单模式及多模式平均等方面优势明显。在预报员对应参考时效上,OTS在24~168 h的24 h累积降水预报中的TS评分也优于主观预报。  相似文献