Attribution Analysis of Runoff Variation in the Yue River Watershed of the Qinling Mountains

In recent decades, global climate change, especially human activities, has led to profound changes in the hydrological cycle and hydrological processes in watersheds. Taking the Yue River watershed in the Qinling Mountains in China as the study area, the Mann–Kendall test and Pettitt mutation test method were used to analyze the various characteristics of hydrological and climatic elements from 1960 to 2018. Then, the elastic coefficient method based on the Budyko framework was used to estimate the elastic coefficient of runoff change on each influencing factor. The results showed that the annual runoff decreased at a rate of 0.038 × 108 m3/a ( P > 0.05 ), and a significant abrupt change occurred in 1990. The annual precipitation and potential evapotranspiration (ET0) increased and decreased, with change rates of 0.614 mm/a and −0.811 mm/a ( P > 0.05 ), respectively. The elasticity coefficients of precipitation, ET0, and the underlying surface were 1.95, −0.95, and −0.85, respectively, indicating that annual runoff was most sensitive to the change in precipitation, followed by the change in ET0, and had the lowest sensitivity to the change in the underlying surface. Underlying surface change is the main factor of runoff decrease; the contribution is 89.07%. The total contribution of climate change to runoff change is 10.93%, in which the contributions of precipitation and ET0 are 17.59% and −6.66%, respectively. The NDVI reflecting underlying surface change has been increasing since 1990, which is an important reason for the runoff decrease.

Study on the Kinematic characteristics of different level jumpers squatting and jumping under different ground

Objective: The purpose of this study is to compare the kinematic differences of different level jumping athletes in the process of squatting on different ground, and to reveal the photomechanical mechanism of the effect of squatting on the different ground on training effect.Methods: The subjects were 11 first-class and above jumping athletes (excellent group) and 11 second-class athletes (ordinary group). The kinematic data were photographed by SONYDCRHC52E high-speed camera with a sampling frequency of 50 frames per second, and the data were analyzed by SIMI-Motion three-dimensional motion analysis system. Subjects squatted and jumped on four kinds of ground (force platform, balance pad, gymnastics pad, and sand) with their hands on their hips.Results: In the intra-group analysis, it was found that the athletes of different levels squatted and jumped on four different kinds of ground, but there was no significant difference only on the balance pad and gymnastics mat (excellent group p=0.344, ordinary group p=1). In the inter-group analysis, it was found that there were significant differences between different levels of athletes in balance pad (p=0.043) and sand (p=0.02). In the buffering stage of the squatting jump, there was no significant difference in the buffering angle displacement of lower limb joints of different athletes on different ground. In the stage of pedal and extension, the angular displacement of the ankle on the middle platform of the excellent group was significantly different from that of the balance pad (p=0.014), gymnastics pad (p=0.017), and sand (p=0.013), but in the ordinary group, the ankle angular displacement of the middle platform was only significantly different from that of the gymnastics pad (p= 0.048) and sand (p=0.017), but not significantly different from that of the balance pad (p=0.166). The maximum angular velocity of the hip joint of athletes of different levels was significantly different among different ground groups. The maximum angular velocity of the ankle joint of the common group was significantly different in force platform and sand (p=0.032), gymnastics ma,t and sand (p=0.008), but there was no significant difference in balance pad.Conclusion: Different places have a great influence on the ordinary group, and on the ground with lower elastic coefficient, the maximum angular velocity of the ankle joint in the ordinary group is much smaller than that in the excellent group, which indicates that the rapid contractile ability of ankle muscles in the ordinary group is poor on the ground with low elastic coefficient. When squatting and jumping on the ground with a lower elastic coefficient, the excellent group has better body control and coordination and lower joint energy loss, which makes the jumping effect better, while the ordinary group squats and jumps on the ground with a low elastic coefficient and unstable ground. The jumping effect is poor.

First-principles study on the elastic, electronic and photocatalytic properties of multiferroic material InFeO3 under strain

The elastic and photocatalytic properties of multiferroic material InFeO3 under strain are calculated through density functional theory. The calculated results indicate that the intrinsic InFeO3 and the strained InFeO3 meet the mechanical stability conditions and hold a relatively larger elastic coefficient than popular multiferroic material BiFeO3. The calculated bandgap and band edge of InFeO3 under tensile strain show that InFeO3 could be a high-efficiency photocatalytic hydrogen production material. InFeO3 under tensile strain holds the ability of photocatalytic water splitting to produce hydrogen with excellent ferroelectric, mechanical properties and absorption of visible light.

Influence of Climate Change and Anthropogenic Activities on Groundwater Level in the Northern Huangqihai Basin, China

The variation in the groundwater level, which is an indicative factor that can reflect changes in both groundwater level and groundwater quantity, was selected as the factor to be analyzed. Rainfall and groundwater exploitation were chosen as the representative factors of climate change and anthropogenic activities, respectively. By applying the elastic coefficient method and other mathematical statistical methods, the influence of climate change and anthropogenic activities on groundwater was analyzed qualitatively and quantitatively. The northern Huangqihai basin was chosen as the study area. The rainfall in the study area showed an increasing trend from 1996–2020, while most variations in groundwater level were negative. This result indicated that the positive influence of rainfall on the variation in the groundwater level in the study area was not enough to offset the negative influence of groundwater exploitation. The correlation between anthropogenic activities and variations in the groundwater level was lower in wet years than in normal years but the highest in dry years. Based on the comparative method of the slope changing ratio of cumulative quantity and the elastic coefficient method, it was determined that the contribution rate of climate change to the variation in groundwater level was 22.08% and that of human activities was 77.92%. Thus, the sustainable development of the groundwater environment can be realized by positively guiding anthropogenic activities and minimizing negative influences.

Study on the Kinematic characteristics of different level jumpers squatting and jumping under different ground

Objective: The purpose of this study is to compare the kinematic differences of different level jumping athletes in the process of squatting on different ground, and to reveal the biomechanical mechanism of the effect of squatting on different ground on training effect. Methods: The subjects were 11 first-class and above jumping athletes (excellent group) and 11 second-class athletes (ordinary group). The kinematic data were photographed by SONYDCRHC52E high-speed camera with a sampling frequency of 50 frames per second, and the data were analyzed by SIMI-Motion three-dimensional motion analysis system. The subjects squatted and jumped on four kinds of ground (force platform, balance pad, gymnastics pad and sand) with their hands on their hips. Results: In the intra-group analysis, it was found that the athletes of different levels squatted and jumped on four different kinds of ground, but there was no significant difference only on the balance pad and gymnastics mat (excellent group p=0.344, ordinary group p=1). In the inter-group analysis, it was found that there were significant differences between different levels of athletes in balance pad (p=0.043) and sand (p=0.02). In the buffering stage of squatting jump, there was no significant difference in the buffering angle displacement of lower limb joints of different athletes on different ground. In the stage of pedal and extension, the angular displacement of ankle on the middle platform of the excellent group was significantly different from that of the balance pad (p=0.014), gymnastics pad (p=0.017) and sand (p=0.013), but in the ordinary group, the ankle angular displacement of the middle platform was only significantly different from that of the gymnastics pad (p= 0.048) and sand (p=0.017), but not significantly different from that of the balance pad (p=0.166). The maximum angular velocity of hip joint of athletes of different levels was significantly different among different ground groups. The maximum angular velocity of ankle joint of common group was significantly different in force platform and sand (p=0.032), gymnastics mat and sand (p=0.008), but there was no significant difference in balance pad. Conclusion: Different places have great influence on the ordinary group, and on the ground with lower elastic coefficient, the maximum angular velocity of the ankle joint in the ordinary group is much smaller than that in the excellent group, which indicates that the rapid contractile ability of ankle muscles in the ordinary group is poor on the ground with low elastic coefficient. When squatting and jumping on the ground with lower elastic coefficient, the excellent group has better body control and coordination and lower joint energy loss, which makes the jumping effect better,

Study on the Kinematic characteristics of different level jumpers squatting and jumping under different ground

Objective: The purpose of this study is to compare the kinematic differences of different level jumping athletes in the process of squatting on different ground, and to reveal the biomechanical mechanism of the effect of squatting on different ground on training effect.Methods: The subjects were 11 first-class and above jumping athletes (excellent group) and 11 second-class athletes (ordinary group). The kinematic data were photographed by SONYDCRHC52E high-speed camera with a sampling frequency of 50 frames per second, and the data were analyzed by SIMI-Motion three-dimensional motion analysis system. The subjects squatted and jumped on four kinds of ground (force platform, balance pad, gymnastics pad and sand) with their hands on their hips.Results: In the intra-group analysis, it was found that the athletes of different levels squatted and jumped on four different kinds of ground, but there was no significant difference only on the balance pad and gymnastics mat (excellent group p=0.344, ordinary group p=1). In the inter-group analysis, it was found that there were significant differences between different levels of athletes in balance pad (p=0.043) and sand (p=0.02). In the buffering stage of squatting jump, there was no significant difference in the buffering angle displacement of lower limb joints of different athletes on different ground. In the stage of pedal and extension, the angular displacement of ankle on the middle platform of the excellent group was significantly different from that of the balance pad (p=0.014), gymnastics pad (p=0.017) and sand (p=0.013), but in the ordinary group, the ankle angular displacement of the middle platform was only significantly different from that of the gymnastics pad (p= 0.048) and sand (p=0.017), but not significantly different from that of the balance pad (p=0.166). The maximum angular velocity of hip joint of athletes of different levels was significantly different among different ground groups. The maximum angular velocity of ankle joint of common group was significantly different in force platform and sand (p=0.032), gymnastics mat and sand (p=0.008), but there was no significant difference in balance pad.Conclusion: Different places have great influence on the ordinary group, and on the ground with lower elastic coefficient, the maximum angular velocity of the ankle joint in the ordinary group is much smaller than that in the excellent group, which indicates that the rapid contractile ability of ankle muscles in the ordinary group is poor on the ground with low elastic coefficient. When squatting and jumping on the ground with lower elastic coefficient, the excellent group has better body control and coordination and lower joint energy loss, which makes the jumping effect better, while the ordinary group squats and jumps on the ground with low elastic coefficient and unstable ground. the jumping effect is poor.

Analysis and Prediction of “AI + Education” Attention Based on Baidu Index—Taking Guizhou Province as an Example

Studying the attention of “artificial intelligence + education” in ethnic areas is of great significance for China for promoting the integrated development of new educational modes and modern technology in the western region. Guizhou province is an area inhabited by ethnic minorities, located in the heart of Southwest China. The development of its intelligent education has strong enlightenment for the whole country and the region. Therefore, this paper selects the Baidu Index of “artificial intelligence (AI) + education” in Guizhou province from 2013 to 2020, analyzes the spatial–temporal characteristics of its network attention by using the elastic coefficient method, and builds the ARIMA model on this basis to predict future development. The results show that the public’s attention to “AI + education” differs significantly in time and space. Then, according to the prediction results, this paper puts forward relevant suggestions for the country to promote the sustainable development of education in western ethnic areas.

Using four different approaches to separate the effects of climate change and human activities on sediment discharge in karst watersheds

<p>Quantifying the relative contributions of climate and human activities to changes in sediment discharge is closely related to regional water resources, soil management and even the healthy operation of ecosystems. However, few studies used different methods to decompose influences of climatic variability and human activities on sediment discharge change, especially in karst regions of southwest China where experiencing severe soil erosion. This study systematically reviewed four different methods including simple linear regression method, double mass curve method, sediment identify factor analysis, and elastic coefficient method to separate the contribution of climate change and human activities to sediment discharge variation in four karst watersheds of southwest during 1955 to 2015. The trend and abrupt change year of sediment discharge in four watersheds were obtained by nonparametric Mann-Kendall test. Result showed that the sediment discharge in four watersheds all decreased significantly (<em>P</em><0.05), and the abrupt change years were 2003, 2003, 2004 and 2004 for Wujiang, Yujiang, Hongshui, and Xijiang watersheds, respectively. The simple linear regression method, double mass curve method and elastic coefficient method all indicated that the sediment discharge was mainly influenced by human activities, with the contribution rate ranging from 73% to 101%. For the sediment identify factor analysis method, the sediment concentration is the principal factor influencing sediment discharge variation, and the contribution rate of sediment discharge varied from 100% to 154%. The results can provide good reference value for evaluating the influence of the climate and human activities on sediment discharge, and is significance for proper formulation of regional soil conservation policy in karst watersheds.</p>