On-spot observation and field reconnaissance of debris flows have revealed that inflexion points in the longitudinal profile of a movable channel may easily become unstable points that significantly affect their entra...On-spot observation and field reconnaissance of debris flows have revealed that inflexion points in the longitudinal profile of a movable channel may easily become unstable points that significantly affect their entrainment behavior.In this study,small-scale flume experiments were performed to investigate the entrainment characteristics of debris flows over two types of inflexion points,namely,a convex point,which has an upslope gradient that is less than the downslope gradient,and a concave point,which has an upslope gradient that is greater than the downslope gradient.It was observed that when debris flowed over a convex point,the entrainment developed gradually and progressively from the convex point in the downstream direction,and the primary control factors were the slope gradient and friction angle.Conversely,when debris flowed over a concave point,the entrainment was characterized by impacting and impinging erosion rather than traditional hydraulic erosion,and the impingement angle of the flow significantly determined the maximum erosion depth and outflow exit angle.An empirical relationship between the topography change and the control factors was obtained from the experimental data.展开更多
[ Objective] The aim was to discuss the optimum fermentation technology of kiwi wine. [Method] Effects of pH, SO2 concentration, fer- mentation temperature, yeast inoculums amount on the quality of kiwi wine were inve...[ Objective] The aim was to discuss the optimum fermentation technology of kiwi wine. [Method] Effects of pH, SO2 concentration, fer- mentation temperature, yeast inoculums amount on the quality of kiwi wine were investigated by single factor experiment and orthogonal experiment. P, esult] The optimum conditions were as follows： fermentation temperature （22 ℃ ）, yeast inoculums （0.20 g/L）, SO2 concentration （60 mg/L） and pH （3.5）. The kiwi wine produced under these conditions was yellowish green, transparent, moderately acidic with strong fruit flavor and aro- ma. [ Conclusion]The study provided a theoretical foundation for the development and production of deeply processed products of kiwifruit.展开更多
This study focuses on examining the characteristics of climate factors and extreme climate events in Northeast China during 1961- 2010 by using daily data from 104 stations, including surface air temperature, precipit...This study focuses on examining the characteristics of climate factors and extreme climate events in Northeast China during 1961- 2010 by using daily data from 104 stations, including surface air temperature, precipitation, wind speed, sunshine duration, and snow depth. Results show that annual mean temperature increased at a significant rate of 0.35℃ per decade, most notably in the Lesser Khingan Mountains and in winter. Annual rainfall had no obvious linear trend, while rainy days had a significant decreasing trend. So, the rain intensity increased. High-temperature days had a weak increasing trend, and low-temperature days and cold wave showed significant decreasing trends with rates of 3.9 d per decade and -0.64 times per decade, respectively. Frequency and spatial scope of low-temperature hazard reduced significantly. Warm days and warm nights significantly increased at 1.0 and 2.4 d per decade, while cold days and cold nights decreased significantly at -1.8 and -4.1 d per decade, respectively. The nighttime warming rate was much higher than that for daytime, indicating that nighttime warming had a greater contribution to the overall warming trend than daytime warming. The annual mean wind speed, gale days, and sunshine duration had significant decreasing trends at rates of-0.21 m s-1 per decade, -4.0 d per decade and -43.3 h per decade, respectively. The snow cover onset dates postponed at a rate of 1.2 d per decade, and the snow cover end date advanced at 1.5 d per decade, which leads to shorter snow cover duration by -2.7 d per decade. Meanwhile, the maximum snow depth decreased at -0.52 cm per decade. In addition, the snow cover duration shows a higher correlation with precipitation than with temperature, which suggests that precipitation plays a more important role in maintaining snow cover duration than temperature.展开更多
基金funded by the Key Research Program of the Chinese Academy of Sciences (Grant No.KZZD-EW-05-01)the National Natural Science Foundation of China (Grant No.41371039)the Open Foundation of State Key Laboratory of Hydraulics and Mountain River Engineering,Sichuan University (Grant No.SKHL1426)
文摘On-spot observation and field reconnaissance of debris flows have revealed that inflexion points in the longitudinal profile of a movable channel may easily become unstable points that significantly affect their entrainment behavior.In this study,small-scale flume experiments were performed to investigate the entrainment characteristics of debris flows over two types of inflexion points,namely,a convex point,which has an upslope gradient that is less than the downslope gradient,and a concave point,which has an upslope gradient that is greater than the downslope gradient.It was observed that when debris flowed over a convex point,the entrainment developed gradually and progressively from the convex point in the downstream direction,and the primary control factors were the slope gradient and friction angle.Conversely,when debris flowed over a concave point,the entrainment was characterized by impacting and impinging erosion rather than traditional hydraulic erosion,and the impingement angle of the flow significantly determined the maximum erosion depth and outflow exit angle.An empirical relationship between the topography change and the control factors was obtained from the experimental data.
文摘[ Objective] The aim was to discuss the optimum fermentation technology of kiwi wine. [Method] Effects of pH, SO2 concentration, fer- mentation temperature, yeast inoculums amount on the quality of kiwi wine were investigated by single factor experiment and orthogonal experiment. P, esult] The optimum conditions were as follows： fermentation temperature （22 ℃ ）, yeast inoculums （0.20 g/L）, SO2 concentration （60 mg/L） and pH （3.5）. The kiwi wine produced under these conditions was yellowish green, transparent, moderately acidic with strong fruit flavor and aro- ma. [ Conclusion]The study provided a theoretical foundation for the development and production of deeply processed products of kiwifruit.
基金supported by the Special Climate Change Research Program of China Meteorological Ad-ministration (No.062700s010c01)the Special Scientific Research Fund of Meteorological Public Welfare Profession of China (No.201206024)
文摘This study focuses on examining the characteristics of climate factors and extreme climate events in Northeast China during 1961- 2010 by using daily data from 104 stations, including surface air temperature, precipitation, wind speed, sunshine duration, and snow depth. Results show that annual mean temperature increased at a significant rate of 0.35℃ per decade, most notably in the Lesser Khingan Mountains and in winter. Annual rainfall had no obvious linear trend, while rainy days had a significant decreasing trend. So, the rain intensity increased. High-temperature days had a weak increasing trend, and low-temperature days and cold wave showed significant decreasing trends with rates of 3.9 d per decade and -0.64 times per decade, respectively. Frequency and spatial scope of low-temperature hazard reduced significantly. Warm days and warm nights significantly increased at 1.0 and 2.4 d per decade, while cold days and cold nights decreased significantly at -1.8 and -4.1 d per decade, respectively. The nighttime warming rate was much higher than that for daytime, indicating that nighttime warming had a greater contribution to the overall warming trend than daytime warming. The annual mean wind speed, gale days, and sunshine duration had significant decreasing trends at rates of-0.21 m s-1 per decade, -4.0 d per decade and -43.3 h per decade, respectively. The snow cover onset dates postponed at a rate of 1.2 d per decade, and the snow cover end date advanced at 1.5 d per decade, which leads to shorter snow cover duration by -2.7 d per decade. Meanwhile, the maximum snow depth decreased at -0.52 cm per decade. In addition, the snow cover duration shows a higher correlation with precipitation than with temperature, which suggests that precipitation plays a more important role in maintaining snow cover duration than temperature.
