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您的检索式：作者名="NIU Baicheng"
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| 1 | Large scale sand saltation over hard surface:a controlled experiment in still air显示文摘Saltation is the major particle movement type in wind erosion process.Saltating sand grains can rebound up to tens of times larger in length and height over hard surface(such as gravel surface)than over loose sand surface.Gravels usually have different faces,causing distinct response of the impacting grains,but the effects of the grain and gravel-surface contact angle on grain rebound are not yet well quantified.We performed full-range controlled experiments of grain saltation using different contact angles,grain sizes and impact speeds in still air,to show that contact angle increases the height of representative saltation path but decreases particle travel length.The results were compared with outputs from the COMprehensive numerical model of SALTation(COMSALT).Large saltation height of 4.8 m and length of 9.0 m were recorded.The maximum and representative saltation height over the gravel surface were found to be about 4.9 times and 12.8 times those over the loose sandy surface,respectively.The maximum saltation length may be reduced by 58%and the representative saltation height may be increased by 77%as contact angle increases from 20°to 40°.We further showed that the collision inertia contributes 60%of the saltation length,and wind contributes to the other 40%.These quantitative findings have important implications for modeling saltation trajectory over gravel surface. | LIU Benli WANG Zhaoyun NIU Baicheng QU Jianjun | 2021 | Journal of Arid Land2021，13，6： | 1 |
| 2 | Aeolian processes on sandy desertification of an alpine meadow: A wind tunnel experiment显示文摘In recent years,the desertification of alpine meadows has become a serious ecological problem and has gradually become a threat to regional economic activities in Maqu County.To reveal the mechanism for sandy desertification of alpine meadows,we conducted wind tunnel experiments on aeolian processes over sandy alpine meadows.Results show that the sandflux profile of mix-sized sediment decays exponentially with increasing height.However,the profile pattern of a group of uniform-sized particles depends on the experimental wind speeds.The profile pattern of all the groups studied can be expressed by exponential decay functions when the wind speed is less than or equal to 16 m/s.while that for all the groups studied can be expressed by a Gaussian distribution function when the wind speed is above 16 m/s.The average saltation heights of mixed sands at wind speeds of 12 m/s,16 m/s,20 m/s,and 24 m/s were 2.74,4.19,5.28,and 6.12 cm,respectively.The mean grain size basically first decreases and then increases with increasing height under different wind speeds.The sorting improves with increasing wind speed,while the kurtosis and skewness show relationships with only the characteristics of the parent soil. | ZhiShan An KeCun Zhang LiHai Tan BaiCheng Niu YanPing Yu | 2020 | Research in Cold and Arid Regions2020，12，1： | 0 |
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