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Simulation of aerodynamic performance affected by vortex generators on blunt trailing-edge airfoils

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Science china(Technological sciences) 2010年第1期53卷 1-7页

作者： YANG Ke1,2.ZHANG Lei1,3.& XU JianZhong1,2.1 Institute of Engineering Thermophysics,chinese Academy of {3.,{2. 100190,china 2.Key Laboratory of Wind Energy Utilization,chinese Academy of {3.,{2. 100190,china 3.Graduate school of chinese Academy of {3.,{2. 100190,china Institute of Engineering Thermophysics Chinese Academy of Sciences Beijing China Key Laboratory of Wind Energy Utilization Chinese Academy of Sciences Beijing China Graduate school of chinese Academy of {2. Beijing China

An investigation was carried out by numerical simulation on a wind turbine airfoil and a blunt trailing-edge airfoil with and without vortex generators (VGs), and the performance of the airfoils was analyzed. By the simulation of airfoil DU 91-W2.2.0 it was verified that the numerical method and model were credible. Based on this airfoil, a new one with a blunt trailing edge of 6% chord was blended by symmetrically adding thickness, and its characteristics curves were obtained through computing at key angles of attack. Additionally, the pressure distribution on blended airfoil was analyzed by comparing to the airfoil without blend. The interaction of streamwise vortices induced by VGs with trailing vortex or separation vortex was considered, followed by the uncovery of how VGs can suppress the boundary layer separation.

关键词： vortex generators airfoil blunt trailing-edge

Land cover changes based on plant successions: Deforestation, rehabilitation and degeneration of forest in the upper Dadu River watershed

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Science china Earth sciences 2005年第12期48卷 2214-2230页

作者： YAN Jianzhong1,2.3. ZHANG Yili1, BAI Wanqi1, LIU Yanhua4, BAO Weikai5, LIU Linshan1, 2.& ZHENG Du1 1. Institute of Geographic sciences and Natural Resources Research, {3. Academy of sciences, beijing 100101, china 2. Graduate school of the {3. Academy of sciences, beijing 10003., china 3. College of Resources and Environment, Southwest Agricultural University, Chongqing 400716, china 4. The Ministry of Science and Technology, P. C. china, beijing 100862. china 5. Chengdu Institute of Biology, {3. Academy of sciences, Chengdu 610041, china Institute of Geographic sciences and Natural Resources Research Chinese Academy of Sciences Beijing China Graduate school of the chinese Academy of {2. Beijing China College of Resources and Environment Southwest Agricultural University Chongqing China The Ministry of Science and Technology P. C. China Beijing China Chengdu Institute of Biology Chinese Academy of Sciences Chengdu China

To link regional land use/cover changes with environmental effects, land cover changes are required to reflect vegetation successions, whereas the land cover classification systems commonly used nowadays cannot serve this purpose. In this paper, a new land cover classification system is established in which land covers are classified by the vegetation succes-sions, taking Zamtang County, Barkam County and Jinchuan County in the upper Dadu River watershed as a study area. Using multi-temporal remote sensing images, the land cover data of 1967, 1986 and 2.00 are obtained by means of integration of unsupervised classification and visual interpretation methods. The database facilitates the study of land use/cover changes, en-vironmental effects and ecological construction. Land cover changes reflect the main ecological processes in the upper Dadu River watershed. The landscape composed mainly of grasslands, wildwoods and alpine scrubs in 1967 was changed to that of grasslands, secondary forests, al-pine scrubs, fragmentary wildwoods, artificial forests, secondary scrubs in 2.00, meanwhile, the landscape got more fragmentized. The total area of the forests decreased by 9.43.. Study results have shown the process of restoration of logged areas in forest centers. From 1967 to 2.00, only 6.86 percents of logged areas were converted to shrubs, meadows or crop-lands, and the rest were converted into artificial forests or secondary forests. So the ecological shelter functions will be restored, stage by stage. Firewood collection, charcoal production and overgrazing are the three major triggers for the extensive degradation of alpine oak forests, Sa-bina tibetica forests and meadows. The arid valley grasslands expanded too. The degradation of vegetation in the southern slopes impairs ecological shelter functions and affects livelihood of local residents, so it is essential to find effective measures for ecological restoration and recon-struction. Field investigations have found

关键词： land use/cover classification, upper Dadu River watershed, vegetation successions, GIS, RS.

Impact of land-use change on hydrological processes in the Maying River basin, china

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Science china Earth sciences 2006年第10期49卷 1098-1110页

作者： WANG Genxu1,3. ZHANG Yu2. LIU Guimin2.& CHEN Lin3.1. Institute of Mountain Hazards and Environment, chinese Academy of {3., Chengdu 610041,{2. 2. Cold and Arid Regions Environmental and Engineering Research Institute, chinese Academy of {3., Lanzhou 73.000,{2. 3. Resource and Environment school, Lanzhou University, Lanzhou 73.000,{2. Institute of Mountain Hazards and Environment Chinese Academy of Sciences Chengdu China Resource and Environment school Lanzhou University Lanzhou China Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Lanzhou China

Since the 1960s, dramatic changes have taken place in land-use patterns characterized by the persistent expansion of cultivated land and a continuous decrease in natural woodland and grassland in the arid inland river basins of china. It is very important to assess the effects of such land-use changes on the hydrological processes so vital for water resource management and sustainable development on the catchment scale. The Maying River catchment, a typical arid inland watershed located in the middle of the Hexi Corridor in northwest china, was the site chosen to investigate the hydrological responses to land-use changes. The annual runoff, base flow, maximum peak flow, and typical seasonal runoff in both spring and autumn flood periods were selected as the variables in the hydrological processes. Statistical-trend analysis and curvilinear regression were utilized to detect the trends in hydrological variables while eliminating the climatic influence. The relationship between cultivated land-use and hydrological variables was analyzed based on four periods of land-use variation data collected since 1965. A runoff model was established composed of two factors, i.e., cultivated land use and precipitation. The impact of land use changes, especially in the large ar- eas of upstream woodland and grassland turned into cultivated lands since 1967, has resulted in a mean annual runoff decrease of 2..12., a base flow decline of 3..3.2}, a drop in the maximum peak discharge of 3..77%, and mean discharge decreases in spring and autumn of 3..05% and 2..87% respectively, of which the contribution of cultivated land expansion to the influence of annual runoff amounts to 77%-80%, with the contribution to the influence of spring discharge being 73.-81%, and that to the influence of base flow reaching 62.-65%. Thus, a rational regulation policy of land use patterns is vitally important to the sustainable use of water resources and the proper development of the entire catchment.

关键词： land-use change, arid inland river catchment, hydrological process, impact, Maying River.

Application of the moist vorticity vector in the analysis of a heavy rainfall event in North china

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Progress in Natural Science:Materials International 2007年第12期17卷 1457-1465页

作者： Zhao Yu1,2.3. Wang Jianguo4 and Xue Deqiang2.1. Laboratory of Cloud-Precipitation Physics and Severe Storms, Institute of Atmospheric Physics, chinese Academy of {3., {2. 10002., china 2. Shandong Provincial Meteorological Observatory, Jinan 2.003., china 3. Graduate University of chinese Academy of {3., beijing 10003., china 4. Shandong Provincial Meteorological Bureau, Jinan 2.003., china) Laboratory of Cloud-Precipitation Physics and Severe Storms Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China Shandong Provincial Meteorological Observatory Jinan 250031 China Graduate University Chinese Academy of Sciences Beijing 100039 China Shandong Provincial Meteorological Bureau Jinan 250031 China

The moist vorticity vector (MVV), defined as (ζa×▽qv)/ρ introduced by Gao et al. is used to study a heavy rainfall event in North china. The MVV has zonal, meridional and vertical components in a three-dimensional framework. Analysis of domain-mean and mass-integrated quantities shows that the variation of the vertical component of the MVV closely follows the variation of the cloud hydrometeors, with a linear correlation coefficient of 0.95, indicating that the vertical component of the MVV is strongly associated with midlatitude convection. Further analysis shows that the vertical component of the MVV reflects the interaction between the horizontal vorticity and the horizontal specific humidity gradient, which can associate dynamic and thermodynamic processes with cloud microphysical processes. Thus, this study can help to understand how the interaction between circulations and clouds aids the development of convection, and the MVV can be used to trace the development and evolution of heavy rainfall.

关键词： moist vorticity vector heavy rainfall modeling study.

Research progress in the inner surface modification of metal tubes by plasma processing

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Progress in Natural Science:Materials International 2006年第11期16卷 1119-1126页

作者： ZHANG Guling~ 1,2.**, WU Xingfang~1, GU Weichao~2. CHEN Guangliang~2. FENG Wenran~2. NIU Erwu~2. LI Li~2. L Guohua~2. CHEN Huan~2. FAN Songhua~2. LIU Chizi~2.and YANG Size~2.1. school of Material Science and Engineering, University of Science and Technology beijing, beijing 100083. china 2. beijing National Laboratory for Condensed Matter Physics, Institute of Physics, chinese Academy of sciences, beijing 100080, china) school of Material Science and Engineering University of Science and Technology Beijing Beijing 100083 China beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences Beijing 100080 China

The recent progress in inner surface hardening of tubes by plasma processing is summerized. Several techniques of inner surface plasma source ion implantation and deposition are introduced, and their advantages and disadvantages are discussed. The basic principles, technical features and new progress of inner surface plasma source ion implantation methods for metal tubes, which were developed in our laboratory, are described in detail. And perspectives of the future technical development for inner surface ion implantation of tubes are presented.

关键词： PSII metal tubes inner surface surface modification.

The crustal structure under Sanjiang and its dynamic implications:Revealed by seismic reflection/refraction profile between Zhefang and Binchuan,Yunnan

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Science china Earth sciences 2005年第9期48卷 1329-1336页

作者： ZHANG Zhongjie1, BAI Zhiming1, WANG Chunyong2. TENG Jiwen1, Lü Qingtian3. LI Jiliang1, LIU Yifeng1 & LIU Zhenkuan4 1. Institute of Geology and Geophysics, chinese Academy of sciences, {2. 10002., china 2. Institute of Geophysics, china Seismological Bureau, {2. 100085, china 3. Institute of Deposition Resource, chinese Academy of Geosciences, beijing 10003., china 4. school of Exploration and Information, china University of Geosciences, {2. 100083. china Institute of Geology and Geophysics Chinese Academy of Sciences Beijing China Institute of Geophysics China Seismological Bureau Beijing China Institute of Deposition Resource Chinese Academy of Geosciences Beijing China school of Exploration and Information China University of Geosciences Beijing China

The fault belts in Sanjiang mainly include Jinshajiang-Honghe fault, Lancangjiang fault and Nujiang fault (called Sanjiang faults) in western Yunnan Province, china. By interpreting the wide-angle seismic reflection/refraction profile between Zhefang and Binchuan, which crosses Tengchong and Baoshan blocks in Dianxi (western Yunnan) tectonic zone, we recon- struct the crustal structure with seismic traveltime tomography for crustal P-wave velocity and the seismic scattering image for crustal seismic reflection structure. In this paper, we firstly present the crustal structure images of P-wave velocity and seismic reflection under the wide-angle seismic profile. These results demonstrate that, the crustal velocity structure and seismic reflec- tion structure along the profile can be divided into 3.segments, and there is an obvious difference of crustal structure among the eastern, the western and the middle segment. Generally, crustal P-wave velocities in the Baoshan segment are 0.1―0.2.km/s slower and seismic reflection am- plitudes from Moho discontinuity are stronger than the other 2.segments. In the studied area, crustal thickness is about 40 km, and shows the thickening tendency from west to east along the profile. Additionally, it can be seen that there is one strong-amplitude seismic reflection event as bright points at the depths of 8―10 km, along the segment of 80―115 km of the profile (south- ward of Tengchong); and seismic reflection wave-field from Moho discontinuity varies obviously along the lateral direction. Finally, we make some discussions on the crustal thickening pattern in the Sanjiang fault belt, structural environment of earthquake development and the contact rela- tionship between the Tengchong block, Banshan block and Luxi trough.

关键词： Sanjiang area wide-angle seismic profile crustal structure.

Evaluation of the Interfacial Adhesion between Brittle Coating and Ductile Substrate by Cross-Sectional Indention

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材料热处理学报 2004年第5B期25卷 1187-1190页

作者： SUJian-yu ZHANGKun CHENGuang-nan InstituteofMechanics ChineseAcademyofSciencesBeijingChina／／GraduateSchooloftheChineseAcademyofSciencesBeijingChina InstituteofMechanics ChineseAcademyofSciencesBeijingChina

The cross-sectional indentation method is extended to evaluate the interfacial adhesion between brittle coating and ductile substrate. The experimental results on electroplated chromium coating/steel substrate show that the interfacial separation occurs due to the edge chipping of brittle coating. The corresponding models are established to elucidate interfacial separation processes. This work further highlights the advantages and potential of this novel indentation method.

关键词：分界面附着刻痕可锻衬底应力涂层铬钢

Reconstruction of precipitation variation from tree rings in recent 1000 years in Delingha, Qinghai

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Science china Earth sciences 2005年第7期48卷 939-949页

作者： SHAO Xuemei1, HUANG Lei1, LIU Hongbin2. LIANG Eryuan1, FANG Xiuqi3.& WANG Lili1 1. Institute of Geographic sciences and Natural Resources Research, chinese Academy of sciences, beijing 100101, china 2. National Climate Center, beijing 100081, china 3. beijing Normal University, beijing 100875, china Institute of Geographic sciences Natural Resources Research Chinese Academy of Sciences Beijing 100101 China National Climate Center Beijing 100081 China beijing Normal University Beijing 100875 China

Using seven well-replicated Qilian juniper (Sabina przewalskii Kom.) ring-width chronologies developed at Zongwulong and Shalike Mts. in the northeastern part of the Qaidam Basin annual precipitation from previous July to current June in the recent 1000 years was re- constructed for Delingha. The reconstruction can capture 63.1% of precipitation variance and the equation was stable over time. For the reconstructed precipitation, wet periods occurred in AD152.—163. and 193.—2.01, whereas dry intervals in 142.—1519 and 163.—1741. In ad- dition, the magnitude in precipitation variation was lower before 143. with about 15 mm, but it increased to 3. mm during the period of 143. to 1850. After 1850, the precipitation variance de- creased again. In contrast to the increase in temperature, a decrease in annual precipitation was evident since the 1990s. The agreement in low-frequency variation between the reconstruction and the glacier accumulation and particulate content in Dunde ice cores during the recent several hundred years suggested that the precipitation reconstructed in this study was rather reliable, and represented a regional signal. This 1000-year reconstruction could benefit our understanding of climatic variation in decadal to century-scale in this region, and provide basic data to climate models and to prediction of future climate in the 2.st century.

关键词： northeastern part of the Qaidam Basin tree-ring width series of Qilian juniper precipitation reconstruction in 1000 years.

Current status and future of acid rain in china

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chinese Science Bulletin 1997年第24期42卷 2076-2081页

作者： DING Guo’an, XU Xiaobing, FANG Xiumei, JIN Shaping, XU Xia, Tang Jie, LIU Qijun, WANG Shufeng and WANG Wenxing1. chinese Academy of Meteorological sciences, {2. 100081,{3. 2. chinese Academy of Environment sciences, {2. 100012.{3. chinese Academy of Meteorological sciences Beijing China chinese Academy of Environment sciences Beijing China

As a part of the national key project of acid rain research, chemical element analysis of rainwater has been carried out based on observation of acid rain network in chinese MeteorologicalAdministration over the years of 1992.and 1993. Samples of precipitation collected from eachacid rain station were taken according to the standard established by chinese MeteorologicalAdministration. pH value was measured with pH meter (accuracy of 0. 01) made in

关键词： acid rain current status future.