我国地质找矿取心（样）钻探设备现状及提高效能的分析研究          下载免费PDF全文

张永勤 《探矿工程》2006,33(8):45-50

概述了我国地质找矿钻探市场现状及前景，分析研究了地质取样钻探传统的立轴钻机及全液压动力头钻机的优缺点及综合效能，针对国家提出加强地质工作的形势及中国的实际状况，提出了完善和改进我国现有钻探设备、提高我国地质找矿取样钻探效率、降低能耗及成本的观点及建议。  相似文献   

一种数据网格的元数据分类管理机制研究   总被引：2，自引：0，他引：2  

张建华  关佶红  王雷春  张俊 《武汉大学学报(信息科学版)》2005,30(1):56-60

网格环境下数据发现和访问的关键问题是应用元数据管理和拷贝元数据管理，针对这一问题，提出了一种元数据分类管理机制。该机制定义了数据模型和应用元数据模式，采用了分类存储的方式对不同的元数据进行管理，并设计了一个基于向导的查询智能体。  相似文献   

防汛信息共享与元数据应用研究   总被引：9，自引：0，他引：9  

李订芳  郭生练  王金星  田向荣 《测绘信息与工程》2003,28(3):1-3

分析了FGDC、CEN／TC287等元数据标准，讨论了基于GIS的防汛信息共享与元数据的应用，设计了防汛信息元数据库，实现了元数据支持下的防汛信息共享。  相似文献   

地理空间元数据和基于网络的数据分发技术   总被引：8，自引：0，他引：8  

李鹤元  李波等 《测绘学院学报》2003,20(1):58-61

首先介绍了元数据、地理空间元数据的概念，探讨了在互联网时代研究地理空间元数据的迫切性和必要性；其次，论述了构建基于网络的数据分发方案的可行性，并就其中的关键技术实现做了深入的探讨；最后，提出了一个以地理空间元数据标准为依据，以Internet为依托的数据分发站点的整体设计方案以及实现这项技术还应考虑的问题。  相似文献   

岩浆驱动破裂的形态研究     

栾锡武  秦蕴珊  宋海斌  石耀霖 《地球物理学进展》2003,18(1):138-141

轴地壳岩浆房是活动扩张中心海洋地壳结构的一个重要组成部分，轴地壳岩浆房通过深部岩浆源的补充，内部岩浆的同化熔融、结晶分异等岩浆房过程，其中的岩浆会破裂上覆的岩石层形成岩浆破裂，并沿岩浆破裂继续向上迁移。本文建立了岩浆迁移的层流模型，从理论上对岩浆迁移问题进行了探讨，并将遗传算法引入到该问题中来，用遗传算法求解了描述岩浆驱动破裂传播的积分方程。如果假设岩浆破裂在远离破裂末梢处的权限宽度为1M，则靠近末梢，破裂的宽度逐渐加大，在末梢处宽度为2m左右。并根据文献对岩浆流体的一些观测参数计算得出，岩浆破裂权限宽度不会很大，一般在1m左右的量级。  相似文献   

打入桩的非线性侧向振动     

王怀忠  汤朝阳 《岩土力学》2004,25(Z2):393-396

针对工程实践中出现的问题,将打入桩的自由段简化为入土端嵌固、锤击端简支的压杆模型,建立桩的振动微分方程,研究锤击轴向力对桩振动频率的影响,并对比锤击初阶频率与桩振动基频的关系得出锤击作用引起柔性桩共振的规律,提出了避开共振影响范围,解决现场工程问题的方法.  相似文献   

沉管灌注桩大面积断桩原因分析          下载免费PDF全文

莫继军 《探矿工程》2005,32(10):14-16

通过2个工程实例分析了沉管灌注桩出现大面积断桩的原因是由于后期基坑开挖不当造成的，并提出了预防断桩出现的一些措施以及对断桩的处理补救措施。  相似文献   

Including spatial distribution in a data‐driven rainfall‐runoff model to improve reservoir inflow forecasting in Taiwan          下载免费PDF全文

Meng‐Jung Tsai  Robert J. Abrahart  Nick J. Mount  Fi‐John Chang 《水文研究》2014,28(3):1055-1070

Multi‐step ahead inflow forecasting has a critical role to play in reservoir operation and management in Taiwan during typhoons as statutory legislation requires a minimum of 3‐h warning to be issued before any reservoir releases are made. However, the complex spatial and temporal heterogeneity of typhoon rainfall, coupled with a remote and mountainous physiographic context, makes the development of real‐time rainfall‐runoff models that can accurately predict reservoir inflow several hours ahead of time challenging. Consequently, there is an urgent, operational requirement for models that can enhance reservoir inflow prediction at forecast horizons of more than 3 h. In this paper, we develop a novel semi‐distributed, data‐driven, rainfall‐runoff model for the Shihmen catchment, north Taiwan. A suite of Adaptive Network‐based Fuzzy Inference System solutions is created using various combinations of autoregressive, spatially lumped radar and point‐based rain gauge predictors. Different levels of spatially aggregated radar‐derived rainfall data are used to generate 4, 8 and 12 sub‐catchment input drivers. In general, the semi‐distributed radar rainfall models outperform their less complex counterparts in predictions of reservoir inflow at lead times greater than 3 h. Performance is found to be optimal when spatial aggregation is restricted to four sub‐catchments, with up to 30% improvements in the performance over lumped and point‐based models being evident at 5‐h lead times. The potential benefits of applying semi‐distributed, data‐driven models in reservoir inflow modelling specifically, and hydrological modelling more generally, are thus demonstrated. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

The data‐driven approach as an operational real‐time flood forecasting model     

Phuoc Khac‐Tien Nguyen  Lloyd Hock‐Chye Chua 《水文研究》2012,26(19):2878-2893

Accurate water level forecasts are essential for flood warning. This study adopts a data‐driven approach based on the adaptive network–based fuzzy inference system (ANFIS) to forecast the daily water levels of the Lower Mekong River at Pakse, Lao People's Democratic Republic. ANFIS is a hybrid system combining fuzzy inference system and artificial neural networks. Five ANFIS models were developed to provide water level forecasts from 1 to 5 days ahead, respectively. The results show that although ANFIS forecasts of water levels up to three lead days satisfied the benchmark, four‐ and five‐lead‐day forecasts were only slightly better in performance compared with the currently adopted operational model. This limitation is imposed by the auto‐ and cross‐correlations of the water level time series. Output updating procedures based on the autoregressive (AR) and recursive AR (RAR) models were used to enhance ANFIS model outputs. The RAR model performed better than the AR model. In addition, a partial recursive procedure that reduced the number of recursive steps when applying the AR or the RAR model for multi‐step‐ahead error prediction was superior to the fully recursive procedure. The RAR‐based partial recursive updating procedure significantly improved three‐, four‐ and five‐lead‐day forecasts. Our study further shows that for long lead times, ANFIS model errors are dominated by lag time errors. Although the ANFIS model with the RAR‐based partial recursive updating procedure provided the best results, this method was able to reduce the lag time errors significantly for the falling limbs only. Improvements for the rising limbs were modest. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

地理国情普查时点核准作业方法探讨     

赵永亮  高明  张佳彬 《测绘与空间地理信息》2016,(2)

通过核实从数据采集到标准时点阶段发生变化的内容,补充新增内容,消除普查前阶段由于资料时效性和外业局限性等导致的现势性不统一现象,对变化的地理国情信息进行核准,使地理国情普查数据成果在时间上达到统一,是开展地理国情监测的基础。  相似文献