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| 1 | Global optimization of signomial geometric programming using linear relaxation显示文摘 | Shen Peiping Zhang Kecun | 2004 | Appl Math Comput2004，150，： | 12 |
| 2 | New discoveries on the effects of desertification on the ground temperature of permafrost and its significance to the Qinghai-Tibet Plateau显示文摘The desert and permafrost conditions of the Qinghai-Tibet Plateau are unique.However,the effects of desertification on the ground temperature of permafrost are currently unclear.Recently,understanding this problem has become more urgent because of increasing desertification on the plateau.For this reason,an observational field experiment was undertaken by the authors at Honglianghe on the Qinghai-Tibet Plateau.Thermistor ground temperature probes were used,and synchronized contrasting observations were made in an open area.Observations of the ground temperature of permafrost below sand layers with a range of thicknesses were made from May 2010 to April 2011.The sand layers were found to play a key role in the protection of the underlying permafrost.The ground temperature below a permafrost table overlain by a thick sand layer was lower than that of the average annual temperature for the natural ground surface,and the temperature drop was roughly constant at 0.2°C.During the warmer part of the year (May to September),the maximum temperature drops over the five months were 3.40,3.72,4.85,3.16,and 1.88°C,respectively.The ground temperature near a permafrost table overlain by a thin sand layer was also lower than that of the average annual temperature for the natural ground surface.However,in this case the average of the annual maximum temperature drop was significantly less,0.71°C.The scientific significance of our preliminary conclusions is not only to present an exploration of the interaction between desertification and permafrost,but also to provide new engineering ideas for protecting the permafrost in regions where construction is required on the Qinghai-Tibet Plateau. | XIE ShengBo QU JianJun ZU RuiPing ZHANG KeCun HAN QingJie | 2012 | Chinese Science Bulletin2012，57，8： | 8 |
| 3 | Effects of gravel mulch on aeolian transport:a field wind tunnel simulation显示文摘The shape,size and coverage of gravels have significant impacts on aeolian sand transport.This study provided an understanding of aeolian transport over the gravel mulching surfaces at different wind velocities by means of a mobile wind tunnel simulation.The tested gravel coverage increased from 5% to 80%,with a progressive increment of 5%.The gravels used in the experiments have three sizes in diameter.Wind velocities were measured using 10 sand-proof pitot-static probes,and mean velocity fields were obtained and discussed.The results showed that mean velocity fields obtained over different gravel mulches were similar.The analysis of wind speed patterns revealed an inherent link between gravel mulches and mean airflow characteristics on the gravel surfaces.The optimal gravel coverage is considered to be the critical level above or below which aeolian transport characteristics differ strongly.According to the present study,the optimal gravel coverage was found to be around 30% or 40%.Threshold velocity linearly increased with gravel coverage.Sand transport rate first increased with height above the wind tunnel floor(Hf),reaching a peak at some midpoint,and then decreased. | KeCun ZHANG WeiMin ZHANG LiHai TAN ZhiShan AN Hao ZHANG | 2015 | Journal of Arid Land2015，7，3： | 5 |
| 4 | Quantitative analysis on the dynamic characteristics of megadunes around the Crescent Moon Spring, China显示文摘The Crescent Moon Spring is a precious natural heritage. However, the dynamic characteristics of megadunes around the Crescent Moon Spring are not well known. This paper quantitatively studied the character- istics and changes of megadunes around the Crescent Moon Spring by interpreting aerial photographs taken in 1985 and 2004 and analysing the dune crestlines and the wind data collected from 2011 to 2012. Results revealed that pyramid dunes were formed by a complex wind regime. The Crescent Moon Spring was not buried by shifting sands because of the stable wind regime and relative stability of pyramid dunes. The crestlines of the dunes around the spring moved northward between 1985 and 2004. The south-facing slip faces were also exposed to wind ero- sion, whereas the other faces were under deposition, thus indicating that the southerly wind was relatively en- hanced. Limiting the scale of tall windbreaks and architectures in the Dunhuang oasis at the north of the spring was necessary to maintain the dynamic equilibrium of the wind regime and sand transport. | YingJun PANG JianJun QU KeCun ZHANG ZhiShan AN QingHe NIU | 2014 | Journal of Arid Land2014，6，3： | 4 |
| 5 | Computational fluid dynamics evaluation of the effect of different city designs on the wind environment of a downwind natural heritage site显示文摘Disturbance in wind regime and sand erosion deposition balance may lead to burial and eventual vanishing of a site.This study conducted 3D computational fluid dynamics(CFD)simulations to evaluate the effect of a proposed city design on the wind environment of the Crescent Spring,a downwind natural heritage site located in Dunhuang,Northwestern China.Satellite terrain data from the Advanced Spaceborne Thermal Emission and Reflection Radiometer(ASTER)Digital Elevation Model(DEM)were used to construct the solid surface model.Steady-state Reynolds Averaged Navier-Stokes equations(RANS)with shear stress transport(SST)k-ωturbulence model were then applied to solve the flow field problems.Land-use changes were modeled implicitly by dividing the underlying surface into different areas and by applying corresponding aerodynamic roughness lengths.Simulations were performed by using cases with different city areas and building heights.Results show that the selected model could capture the surface roughness changes and could adjust wind profile over a large area.Wind profiles varied over the greenfield to the north and over the Gobi land to the east of the spring.Therefore,different wind speed reduction effects were observed from various city construction scenarios.The current city design would lead to about 2 m/s of wind speed reduction at the downwind city edge and about 1 m/s of wind speed reduction at the north of the spring at 35-m height.Reducing the city height in the north greenfield area could efficiently eliminate the negative effects of wind spee.By contrast,restricting the city area worked better in the eastern Gobi area compared with other parts of the study area.Wind speed reduction in areas near the spring could be limited to 0.1 m/s by combining these two abatement strategies.The CFD method could be applied to simulate the wind environment affected by other land-use changes over a large terrain. | BenLi LIU JianJun QU QingHe NIU JunZhan WANG KeCun ZHANG | 2014 | Journal of Arid Land2014，6，1： | 4 |
| 6 | Morphology and formation mechanism of sand shadow dunes on the Qinghai-Tibet Plateau显示文摘The formation and development of dunes depend on wind-blown sand movement which is affected by the characteristics of sand material, topography, wind regimes and other factors. In this paper, we investigated two sand shadow dune groups in Shigatse and Za'gya Zangbo of Tibet and an individual dune in Da Qaidam of Qinghai, and analyzed their topographies and morphologies, and the physical characteristics of the sand, wind regime and sand transport. Formed under harsh conditions behind hills, these mature sand shadow dunes are hundreds of meters long, have significant ridges and crescent dunes downwind, and have a hill pass on one or both sides. Wind tunnel experiments revealed that the hill gap and wind velocity are important factors in the formation of these dunes. Sand shadow dunes formed only when the gap spacing is two-thirds of the hill height. When wind velocities are 20 m/s, the sand body is divided into two parts. The hill pass allows the transport of sand by wind, creating a 'narrow-pipe effect', which causes the transported material to gradually accumulate in the center of the shadow zone. We observed that the following are needed for sand shadow dunes to form:(1) strong winds, sufficient sand, suitable obstacles and a dry climate;(2) one or both sides of the obstacle forming the shadow zone must have a hill pass; and(3) the windward side of the obstacle must have a wide, flat area, providing adequate spacing for wind flow and transport of material and the leeward side must have a sufficiently broad, flat area to allow the release of the transported material. Research results on these newly discovered dunes on the Qinghai-Tibet Plateau could contribute to the understanding of dune geomorphology. | JianHua XIAO JianJun QU ZhengYi YAO YingJun PANG KeCun ZHANG | 2015 | Journal of Arid Land2015，7，1： | 4 |
| 7 | Barchans of Minqin:quantifying migration rate of a barchan显示文摘The migration speed of a typical barchan on the border of Minqin oasis,Gansu Province,northwestern China,was estimated by means of two methods.One is on the basis of a simple physical model and short-term field measurements.The other comes from the combination of the barchan internal structure detected by ground-penetrating radar and optical/radiocarbon dating techniques.The upper limit of migration speed given by conventional C-14 dating is 3.42 m/yr.The optically stimulated luminescence dating indicates that the time-average migration speed of the studied barchan was 1.78 m/yr in 28 years prior to 2007.The physical estimation further suggests that the annual migration speed has increased in recent years. | ZhenTing Wang 1,2*,Hui Zhao 1,KeCun Zhang 1,XiaoZong Ren 2,FaHu Chen 2,Tao Wang 1 1.Key Laboratory of Desert and Desertification,Cold and Arid Regions Environmental and Engineering Research Institute,Chinese Academy of Sciences,Lanzhou,Gansu 730000,China.2.CAEP,Key Laboratory of Western China’s Environmental Systems(Ministry of Education),Lanzhou University,Lanzhou,Gansu 730000,China. | 2009 | Research in Cold and Arid Regions2009，1，2： | 4 |
| 8 | Thermodynamic Effects on Particle Movement:Wind Tunnel Simulation Results显示文摘Sand/dust storms are some of the main hazards in arid and semi-arid zones. These storms also influence global environmental changes. By field observations, empirical statistics, and numerical simulations, pioneer researchers on these natural events have concluded the existence of a positive relationship between thermodynamic effects and sand/dust storms. Thermodynamic effects induce an unsteady stratified atmosphere to influence the process of these storms. However, studies on the relationship of thermodynamic effects with particles (i.e., sand and dust) are limited. In this article, wind tunnel with heating was used to simulate the quantitative relationship between thermodynamic effects and particle movement on different surfaces. Compared with the cold state, the threshold wind velocity of particles is found to be significantly decrease under the hot state. The largest decrease percentage exceedes 9% on fine and coarse sand surfaces. The wind velocity also has a three-power function in the sand transport rate under the hot state with increased sand transport. Thermodynamic effects are stronger on loose surfaces and fine particles, but weaker on compacted surfaces and coarse particles. | NIU Qinghe QU Jianjun ZHANG Kecun LIU Xianwan | 2012 | Chinese Geographical Science2012，22，2： | 2 |
| 9 | Classification of full-polarization ALOS-PALSAR imagery using SVM in arid area of Dunhuang显示文摘Classification is an important process in interpretation of synthetic aperture radar(SAR) imagery. As an advanced instrument for remote sensing, the polarimetric SAR has been applied widely in many fields. The main aim of this paper is to explore the ability of the full-polarization SAR data in classification. The study area is a part of Dunhuang, Gansu Province, China. An L-band full-polarization image of Dunhuang which includes quad-polarization modes was acquired by the ALOS-PALSAR(Advanced Land Observing Satellite–the Phased Array type L-band Synthetic Aperture Radar). Firstly, new characteristic information was extracted by the difference operation, ratio operation, and principal component transform based on the full-polarization(HH, HV or VH, VV) modes SAR data. Then the single-, dual-, full-polarization SAR data and new SAR characteristic information were used to analyze quantitatively the classification accuracy based on the Support Vector Machines(SVM). The results show that classification overall accuracy of single-polarization SAR data is poor, and the highest is 56.53% of VV polarization. The classification overall accuracy of dual-polarization SAR is much better than single-polarization, the highest is 74.77% of HV & VV polarization data. The classification overall accuracy of full-polarization SAR is 80.21%, adding the difference characteristic information, ratio characteristic information and the first principal component(PC1) respectively, the overall accuracy increased by 3.09%, 3.38%, 4.14% respectively. When the full-polarization SAR data in combination with the all characteristic information, the classification overall accuracy reached to 91.01%. The full-polarization SAR data in combination with the band math characteristic information or the PC1 can greatly improve classification accuracy. | JunZhan Wang JianJun Qu WeiMin Zhang KeCun Zhang | 2016 | Research in Cold and Arid Regions2016，8，3： | 2 |
| 10 | A nonmono-tone trust region method for unconstrained optimization显示文摘 | Mo Jiangtao Zhang Kecun Wei Zengxin | 2005 | Applied Mathematics and Computation2005，171，： | 1 |
| 11 | Temporal variations of sandstorms in Minqin oasis during 1954–2000显示文摘 | Kecun Zhang Jianjun Qu Ruiping Zu Haiyan Fang | 2005 | Environmental Geology2005，，2： | 1 |
| 12 | A global optimization algorithm using linear relaxation 显示文摘 | Qu Shaojian Yin Hongyou Zhang Kecun | 2006 | Applied Mathematics and Computation2006，178，： | 1 |
| 13 | Optimal pro-portional reinsurance and investment with transaction cost maximizing the terminal wealth 显示文摘 | Xinli ZHANG Kecun ZHANG Xingjiang YU | 2008 | Insurance: Mathematical and Eco- nomics:2008，44，： | 1 |
| 14 | Wind energy environments and aeolian sand characteristics along the Qinghai-Tibet Railway, China显示文摘 | Zhang Kecun Qu Jianjun Han Qingjie | 2012 | Sedimentary Geology2012，273，： | 1 |
| 15 | A new SQP method of feasible directions for nonlinear programming 显示文摘 | Zhu Zhibin Zhang Kecun | 2004 | Applied Mathematics and Computation2004，148，5： | 1 |
| 16 | A variant of SQP method for inequality constrained optimization and its global convergence显示文摘 | MO Jiangtao ZHANG Kecun WEI Zengxin | 2006 | Journal of Computational and Applied Mathematics2006，197，1： | 1 |
| 17 | Damage by wind-blown sand and its control along Qinghai-Tibet Railway in China显示文摘 | Zhang Kecun Qu Jianjun Liao Kongtai | 2010 | Aeolian Research2010，1，3： | 1 |
| 18 | A global optimization using linear relaxation for generalized geometric programming显示文摘 | Qu Shaojian Zhang Kecun Wang Fusheng | 2008 | European Journal of Operational Research2008，190，2： | 1 |
| 19 | Damage by wind-blown sand and its control along Qinghai-Tibet Railway in China显示文摘 | Zhang Kecun Qu Jianjun Liao Kongtai | 2010 | Aeolian Research2010，1，3： | 1 |
| 20 | A new global optimization algorithm for signomial geometric programming via lagrangian relaxation显示文摘 | Qu Shaojian Zhang Kecun Ji Ying | 2007 | Applied Mathematics and Computation2007，184，2： | 1 |
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