Wang X.,Tsinghua National Laboratory for Information Sciences and Technology |
Li H.,Heibei University of Engineering |
Wang J.,Tsinghua National Laboratory for Information Sciences and Technology |
Xiao L.,Tsinghua National Laboratory for Information Sciences and Technology
Electronic Materials Letters | Year: 2014
The influence of an Al interlayer on the crystalline quality and surface morphology of AlN epitaxial layers is investigated. 100 nm thick (0002) oriented AlN layers were grown on Si (111) substrates by metal organic chemical vapor deposition. Al interlayers were introduced through Al soaking, followed by nitridation for different lengths of time. When the nitridation time was 0 s, the AlN surface was uneven. At a nitridation time of 15 s, the AlN epilayer started to transform into a smooth surface. When the nitridation time was increased to 40 s, the AlN films had rough surfaces. X-ray diffraction measurements showed that the full width at half maximum of the (0002) peak decreased to 801.9 arcsec by introducing the Al interlayer for a nitridation time of 25 s. The roughness of the AlN surface was reduced from 5.30 nm to 1.91 nm compared with the films without an Al interlayer. The Al interlayer improved the crystalline quality and surface roughness of the AlN films. An optimized nitridation time was important in achieving an appropriate surface roughness for high quality crystals of AlN on Si (111) surfaces.[Figure not available: see fulltext.]. © 2014, The Korean Institute of Metals and Materials and Springer Science+Business Media Dordrecht.
Li X.-L.,Xi'an University of Technology |
Li X.-L.,North China University of Water Conservancy and Electric Power |
Li X.-Y.,Hydrology Bureau of Yellow River Conservancy Commission |
Wang S.-Q.,Heibei University of Engineering |
Fei L.-J.,Xi'an University of Technology
International Journal of Applied Environmental Sciences | Year: 2013
In order to alleviate problems of social and economic development due to water shortage, experiments of rotational irrigation with fresh water and brackish water of different degrees of mineralization as well as direct irrigation with brackish water were carried out to find suitable ways of rotational irrigation for the region to solve the issue of water shortage for agriculture. The experiments shows that rotational irrigation mode, which irrigates with fresh water twice before the turning green stage, will take away some salt because of soil leaching, leading to the result that the salt-content of the soil after the first irrigation with water of 2~3g/L degree of mineralization is lower than the background value; direct irrigation with brackish water makes the salt in the soil move downward with water during the whole growing period of wheat, resulting in depositions of salt in soils of different depth. The salt-content of surface soil increases with rising of temperature and evaporation, and it decreases gradually as the depth of soil increases; the rotational irrigation mode, which includes two times of fresh water irritations before the turning green stage and three times of irrigations with water of 2~3g/L degree of mineralization after that stage increases the yield of winter wheat rather than decreases it. After the total volume of irrigation water reaches a certain level, the yield of wheat decreases as the volume of irritation water increases. © Research India Publications.
Li S.,Heibei University of Engineering |
Zhao J.,Wuan bureau of environmental protection |
Wang Y.,Wenzhou University |
Zhang H.,Heibei University of Engineering |
Qu J.,Heibei University of Engineering
Advances in Systems Science and Applications | Year: 2010
The chemical industry district of Xingtai city is a case of predicting groundwater pollution by finite element method. The researched area is 7.20 km2. Polluted aquifer is an artesian one. It is consisted of fine sand and sub-clay, and 15.60 - 40.60 m deep under the ground. Cl- and other four pollutants are selected as predicting factors. Predicting period is from 2003 to 2010. The future dynamic state of groundwater pollution in the district has been predicted, which provides the scientific basis for planning groundwater quality in the chemical industry district of Xingtai city.
Ren X.,Heibei University of Engineering |
Wang J.,Heibei University of Engineering |
Li X.,SJZ.Modern Space Architecture Design Do.ltd. |
Jia L.,Handan Residential Company
Applied Mechanics and Materials | Year: 2012
The paper builds up the model for exergy analysis of vapor compression refrigeration. According to the exergy analysis, it appears exergy loss degree of the main units in the system, and points out the way of reducing exergy loss and the approach utilizing energy rationally, and proceeds with exergy loss compare with aiming at that if condenser in surplus heat recycling. Conclusion is that adopting surplus heat recycling can reduce exergy loss. Furthermore, it analyzes exergy loss to a actual refrigeration aiming at temperature regulation, and provides the theory reference for improvement and optimization of the system. © (2012) Trans Tech Publications, Switzerland.
Zhang X.,CAS Institute of Remote Sensing Applications |
Zhu C.-M.,Jiangsu University |
Luo J.-C.,CAS Institute of Remote Sensing Applications |
Li W.-Q.,Heibei University of Engineering |
Yang J.-W.,Heibei University of Engineering
Guang Pu Xue Yu Guang Pu Fen Xi/Spectroscopy and Spectral Analysis | Year: 2013
Precise spectral characterization is fundamental for thematic information extraction. Because different types of water have different spectral features, which result in the difficulty of automatic retrieving water information precisely from the whole film. The present paper explored a new approach to water adaptive extraction based on local end member spectral characterization (LESC). Firstly, through the spectral index calculation the primary water identification was achieved. Secondly, through spatial analysis and automatic end member extraction, we can get the water end member in part of region. Thirdly, according to the end member spectral, we can calculate local end member spectral similarity and histogram of similarity. Finally, through the histogram spectral analysis the optimal segmentation threshold was determined and according to the results the segmentation threshold was adjusted to fulfill water information extracting automatically and accurately. Experiments results show that through local end member spectral characterization the precision of extraction result can be promoted. The proposed method can extract all types of water information precisely and is not affected by different spectral feature.