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11.
Land is one of the prime natural resources. A city grows not only by population but also by changes in spatial dimensions. Urban population growth and urban sprawl induced land use changes and land transformation. The land transformation is a natural process and cannot be stopped but it can be regulated. Many geographical changes at the urban periphery are associated with the transfer of land from rural to urban purpose. There is an urgent need for fast growing areas like Delhi, which can be easily done by high-resolution remote sensing data. Land use/land cover of North West of Delhi has been analyzed for the time period of 1972?C2003. The remote sensing data used in study is Aster image of 2003 with a spatial resolution of 15?m and other data of 1972 Survey of India (SOI) toposheet at the scale of 1:50,000. Supervised digital classification using maximum likelihood classifier was applied for preparing land use/land cover. A change detection model was applied in ERDAS Imagine to find out the land use/land cover during 1972 to 2003. Eight land use classes was identified but main dominated classes were built up and agricultural land. A drastic change has been recorded during 30 years of time i. e. (1972-2003). In 1972, 92.06% of the land was under agricultural practice, which reduced to 64.71% in 2003. This shows 27.35% decrease in agricultural land in three decades. On the other hand built up area was 6.31% in 1972, which increased to 34% in 2003. One of the main cause of this land use change is the population growth due to the migration in the district from small cities and rural areas of Delhi.  相似文献   
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This article simulates the vortex-induced oscillations of a rigid circular cylinder with elastic support using the new ANSYS CFX rigid body solver. This solver requires no solid mesh to setup FSI (Fluid Structure Interaction) simulation. The two-way case was setup in CFX only. Specific mass of the cylinder and flow conditions were similar to previous experimental data with mass damping parameter equal to 0.04, specific mass of 1 and Reynolds number of 3800. Two dimensional simulations were setup. Both one-degree-of-freedom and two-degree-of-freedom cases were run and results were obtained for both cases with reasonable accuracy as compared with experimental results. Eight-figure XY trajectory and lock-in behavior were clearly captured. The obtained results were satisfactory.  相似文献   
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Effects of Land Transformation on Water Quality of Dal Lake,Srinagar, India   总被引:3,自引:0,他引:3  
The present study focuses on the growing human needs which drive the native boatmen of the Kashmir valley (Hanjis) that bring the interchanges of land use/cover classes in Dal lake and its environs of Srinagar city. Further to assesses the effects of land transformation on lake water quality. The results suggested that the significant land use changes have been occurred during the past of 30 years (1981–2011). Besides this, interchange of land has taken place between different land uses classes, which has resulted into lake water pollution due the addition of various nutrients/pollutant discharged from Hanjis activities. The study concludes that the land transformation has converted the once fresh water lake much deteriorated pond.  相似文献   
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Attractiveness of the open urban spaces, such as plazas or squares, depends on the visitor’s thermal comfort. In this respect, it is important to assess the environment of such open space along with the demographic factors of the visitors. This study used the soft-computing method of adaptive neuro fuzzy inference system (ANFIS) to investigate the thermal comfort of visitors at a public square in Iran during hot and cold weather conditions. The ANFIS process for variable selection was implemented in order to detect the predominant variables affecting the individual’s comfortable feeling. Model’s training and testing data were collected through the field measurement and survey during hot and cold times of the year. We used 18 input parameters, representative of demographic and environmental factors, to compute visitor’s thermal sensation, comfort feeling, and 4 common indices, namely the mean radiant temperature (Tmrt), mean physiological equivalent temperature (PET), standard effective temperature (SET) and predicted mean vote (PMV). The results indicated that among the examined factors, the air temperature (Ta) is the most influential parameter and best predictor of accuracy for the individual’s comfort feeling at the studied urban square. The results show that Ta can best predict the common indices of outdoor comfort, namely the PMV, PET, SET, thermal sensation, Tmrt, and comfortable felling compared to other parameters with the least error of 1.94, 18.87, 13.67, 0.91, 7.80, and 0.34 %, respectively. Some of the main advantages of the ANFIS scheme are that it is adaptable to the optimization and adaptive methods, and is computationally efficient.  相似文献   
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The Asymmetric Friction Connection (AFC) remains elastic during moderate earthquake shaking but slides and dissipates energy through friction during severe earthquake shaking. The sliding friction forces developed are dependent on the clamping force in the connection which is provided by fully tensioned bolts which pass through slotted holes. During sliding these bolts are subject to moment and shear as well as axial force. Moment–shear–axial force interaction reduces the clamping axial force on the sliding interfaces thereby reducing the sliding shear resistance (Vss). Two methods to evaluate the moment–shear–axial force interaction have been proposed so that the sliding shear strength can be quantified, but as yet, these methods are not robust. This paper describes the results of 60 tests undertaken to improve the two methods, namely the moment–shear–axial force bolt model and the effective coefficient of friction method, for AFCs with high hardness steel shims. The bolts were M16 to M30 bolts and cleat thicknesses ranged from 12 mm to 25 mm. It is shown that either method may be used in design as the results obtained are similar. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   
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A tropical cyclone (TC) precipitation prediction scheme has been developed based on the physical quantities of the NCEP/NCAR reanalysis data as potential predictors and using fuzzy neural network (FNN) model. TC precipitation samples from 172 tropical cyclones (TCs) affecting Guangxi, China, spanning 1980–2015 are used for model development. The FNN model input is constructed from potential predictors by employing both a stepwise regression method (SRM) and a locally linear embedding (LLE) algorithm. The LLE algorithm is capable of finding meaningful low-dimensional architectures hidden in their nonlinear high-dimensional data space and separating the underlying factors. In this scheme, the newly developed model, which is termed the FNN–LLE model, is used for daily TC precipitation prediction from 20:00 (Beijing Time, or BT) of the previous day to 20:00 BT of the current day at 89 stations covering Guangxi, China. Using identical modeling samples and independent samples, predictions of the FNN–LLE model are compared with the widely used SRM and interpolation method using the fine-mesh data of the European Centre for Medium-Range Weather Forecasts (ECMWF) in terms of the performance of TC rainfall prediction at 89 stations in Guangxi. The root-mean-square error (RMSE), bias, and equitable threat score (ETS) results were employed to assess the predicted outcomes. Results show that the FNN–LLE model is superior to the interpolation method by ECMWF and SRM for TC precipitation prediction with RMSE values of 21.94, 24.07, and 25.22 in FNN–LLE model, interpolation method by ECMWF and SRM, respectively. Moreover, FNN–LLE model having average bias and ETS values close to 1.0 gave better predictions than did the interpolation method by ECMWF and SRM.  相似文献   
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Coal mining has serious impacts on local environment, including damage to the land and soil by subsidence, damage to ground-water systems through the fracturing and subsiding of overlying rocks, contamination of surface waters with acid mine drainage, and pollution of the atmosphere by release of toxic gases. The damage to ground water and its consequent impacts on the regional environment is the core of research of the coal mining from the perspective of environment protection. The present paper focuses on the changes of surface vegetation coverage, the pollutants released from pit coal power plants, and the damages to the ground aquifers induced by mining activities in arid Eastern Junggar coalfield of China. At first, the authors investigated the changes of surface vegetation coverage, since mining began in the 2000s using Landsat data. Results show that the low surface vegetation coverage (grade 1 plus grade 2) in the southern part of the region decreased from 11.62?×?108 m2 in 2003 to 9.57?×?108 m2 in 2017 (?17.6%), while it increased from 11.58?×?108 m2 in 2003 to 12.70?×?108 m2 in 2017 (+?9.7%) in the eastern part. The high surface vegetation coverage (grade 3 plus grade 4) in the southern part increased from 1.94?×?108 m2 in 2003 to 4.00?×?108 m2 in 2017 (+?106.2%), while it decreased from 4.39?×?108 m2 in 2003 to 3.26?×?108 m2 in 2017 (?25.74%) in the eastern part. The data of annual precipitation during the same period in this area show that the changes of surface vegetation coverage have less relationship with the annual precipitation, which indicates that the mining activities is probably the major factor for that. Second, a statistic of air pollutants generated from pit coal power plants was made based on data of references. Results show that the estimated gaseous pollutant emissions increased as 865.23 tons of smoke particles, 5940.73 tons of SO2, and 7584.48 tons of NO2 in 2013, which increased rapidly with 9.73 times the smoke particle, 21.69 times the SO2, and 9.24 times the NO2 than that of 2007. And then, the physical and numerical simulation of the damage of mining activities to aquifers was made to show the permeability of the reference points of overlying aquifers varies associated with mining activities. Results show that the porous rock matrix permeability has a negative relationship with fluctuation during mining, while the fracture permeability shows a positive one. Finally, a case investigation in southern area surrounding this coalfield was illustrated. Result shows that the local ground-water level decreased by 16 m difference from the altitude level of?+?774 m in 2003 to?+?758 m in 2013. Data and results from this study presented the already and the potential pollutions and damages to local environment induced by the mining activities in this region.

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Natural Resources Research - This study developed a new perspective of artificial neural networks using dimensional analysis to be applicable to certain prediction problems. To this end,...  相似文献   
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