Zhang J.-E.,China Institute of Water Resources and Hydropower Research |
Lu C.-Y.,China Institute of Water Resources and Hydropower Research |
Qin D.-Y.,China Institute of Water Resources and Hydropower Research |
Wang R.-D.,HydroChina Beijing Engineering Corporation
Shuili Xuebao/Journal of Hydraulic Engineering | Year: 2012
The distributed hydrology model-MODCYCLE was used to simulate the water cycle in Tianjin, It includes the analyzsis on water transfer relationship and basin water balance influenced by human activities in the period from 1997 to 2004. The model has been verified on five aspects, and the results show that the whole annual average recharge amount of Tianjin is this period is 7.409 billion m3, the whole annual average ET amount is 7.126 billion m3, the whole annual average discharge amount is 0.870 billion m3, and the whole annual average change amount is -0.582 billion m3. The ratio of precipitation to the whole recharge is 74.2%. Among the composition of total ET, the amount of land ET is the largest, amounting 76.8%. Most discharge, amounting 97.3%, flows into the Bohai Bay. The soil water resource, surface water resource, and the shallow groundwater resource all keep balance, but the deep groundwater resource needs pumping because of water recharge shortage. According to this study, it is suggested that the MODCYCLE model has supplied a method and tool to describe the characteristics of the artificial-natural dual water cycle on regions.
Hou A.,Tsinghua University |
Ni G.,Tsinghua University |
Lei Z.,Tsinghua University |
Jing S.,HydroChina Beijing Engineering Corporation
Shuili Fadian Xuebao/Journal of Hydroelectric Engineering | Year: 2013
Change in impervious ratio of ground surface is an important index of urbanization. This paper presents a direct estimation of impervious surface distribution in the plain area of Beijing from landsat thematic mapper (ET) data of 1995 and 2007 with a fully constrained linear spectral mixture model of four endmembers, i. e. high albedo, low albedo, vegetation, and soil. The estimation accuracy of this ratio in 2007 was evaluated by using a high-precision geographic vector map of 2006~2007, and an overall RMS error of 17.3% was obtained. Comparison of the impervious surface distributions in 1995 and 2007 shows the main regions of urbanization in Beijing and their scales. Results show that in this period the urbanization were prominent in Shunyi, Tongzhou, Fangshan, Daxing, Chaoyang and Changping. This direct estimation method from Landsat TM images provides important information to the studies of urbanization, urban hydrological and energy cycle. © Copyright.
Wang C.,China Coal Technology and Engineering Co. |
Li J.,HydroChina Beijing Engineering Corporation |
Sun R.,China Coal Technology and Engineering Co.
Jilin Daxue Xuebao (Diqiu Kexue Ban)/Journal of Jilin University (Earth Science Edition) | Year: 2014
Brazing method was introduced into designing and manufacturing diamond drill bit with high matrix to improve its drilling efficiency and extend its life. Firstly, impregnated diamond blocks with good wear resistance were manufactured by hot pressing method. Then new steel body of drill bit including multilayer nozzles and water way was designed, and the welding grooves were formed between two nozzles. Lastly, the impregnated diamond blocks were welded in the drill bit steel body. The life of diamond drill bit manufactured by welding method was improved obviously. Field experimental results showed that the drilling efficiency of two Φ75/54.5 mm high matrix diamond bits was increased by 41.7% and 8.3% respectively, their lives were improved by 50.4% and 32.9% respectively compared with the conventional one. The two times braze welding method takes the advantage of hot pressing method, solves the breaking and blocking off problem of drilling bit, and improves its life greatly.
Wang W.,Beijing Institute of Technology |
Liu Z.,Beijing Institute of Technology |
Song X.,Beijing Institute of Technology |
Ma X.,HydroChina Beijing Engineering Corporation
International Conference on Signal Processing Proceedings, ICSP | Year: 2012
This paper introduces a hybrid imaging mode of spaceborne SAR, which holds the particular advantages of high-resolution and large imaging swath, and it has been uniquely applied to the TECSAR Satellite of Israel successfully in 2008. According to the azimuthal time-frequency analysis of mosaic mode, imaging method is presented and ECS algorithm is selected for processing a single mosaic data. In order to resolve the inevitable Doppler ambiguity, a data preprocessing algorithm is utilized to improve the traditional ECS algorithm. Finally, simulation results demonstrate the validity of the proposed imaging method. © 2012 IEEE.
Li G.B.,China Agricultural University |
Li G.B.,HydroChina Beijing Engineering Corporation |
Li Y.K.,China Agricultural University |
Li Y.K.,CAS Research Center for Eco Environmental Sciences |
And 7 more authors.
Irrigation Science | Year: 2012
Emitter clogging, a phenomenon commonly seen in reclaimed wastewater drip irrigation systems, is a severe obstacle to the wide applications and popularization of the irrigation technology. Some experiments showed that the emitter clogging was tightly related to biofilms formation attached to the irrigation system. In this paper, two types of wastewaters reclaimed respectively by fluidized-bed reactor (FBR) process and biological aerated filter (BAF) process were chosen as the experiment objects and then the effects of the average velocity on the growth and topography of biofilms attached to the irrigation laterals were studied. The parameters of biofilms reached their maximal values at a critical velocity of 0.45 m/s. The formation of biofilms was primarily controlled by the transport of the nutrients and suspended particles within the laterals when the average velocity is below the critical velocity, whereas it was primarily controlled by the hydraulic shear force when above the critical velocity. The main mechanism for emitter clogging was that the biofilms detached from laterals accumulated and grew at the inlets and outlets of emitters. A similar variation pattern was observed for both reclaimed wastewaters. However, the growth of biofilms for BAF process was more affected by the shear force than that for FBR process, since the nutrients and suspended particles for BAF were larger than those for FBR. © 2011 Springer-Verlag.