The principle of improving the torque amplification factor of E-TVDs with six elements is illustrated in this paper.A velocity diagram is used to study speed and torque relationships.The results reveal that the torque...The principle of improving the torque amplification factor of E-TVDs with six elements is illustrated in this paper.A velocity diagram is used to study speed and torque relationships.The results reveal that the torque amplification factor is the linear combination of the ratio of the differentials of the four elements and the ratio of planetary gear units,and its maximum value is easily more than 10.The E-TVDs with six elements are classified into three types,and there are six different configurations for each type.The torque amplification factor and the speed of interconnection between two planetary gear units are employed to evaluate the different characteristics of each E-TVD with six elements.The feasible configurations of a differential with four elements are also presented by the analysis of velocity level and planarity.This paper helps to further the understanding of the complex interconnection of the planetary gear units in E-TVDs with six elements and the differences of their characteristics.展开更多
High-precision proper motions and radial velocities of 1046 stars are used to determine member stars using three-dimensional (3D) kinematics for open clus- ter NGC 188 based on the density-based spatial clustering o...High-precision proper motions and radial velocities of 1046 stars are used to determine member stars using three-dimensional (3D) kinematics for open clus- ter NGC 188 based on the density-based spatial clustering of applications with noise (DBSCAN) clustering algorithm. By implementing this algorithm, 472 member stars in the cluster are obtained with 3D kinematics. The color-magnitude diagram (CMD) of the 472 member stars using 3D kinematics shows a well-defined main sequence and a red giant branch, which indicate that the DBSCAN clustering algorithm is very effective for membership determination. The DBSCAN clustering algorithm can ef- fectively select probable member stars in 3D kinematic space without any assumption about the distribution of the cluster or field stars. Analysis results show that the CMD of member stars is significantly clearer than the one based on 2D kinematics, which al- lows us to better constrain the cluster members and estimate their physical parameters. Using the 472 member stars, the average absolute proper motion and radial velocity are determined to be (PMα, PMδ) = (-2.58 ± 0.22, +0.17 ± 0.18) mas yr-1 and Vr = -42.35 ± 0.05 km s-1, respectively. Our values are in good agreement with values derived by other authors.展开更多
This study presents experimental results of the change in threshold friction velocity and dust emission strength as a function of soil moisture content. The dust and soil moisture data were obtained from irrigated plo...This study presents experimental results of the change in threshold friction velocity and dust emission strength as a function of soil moisture content. The dust and soil moisture data were obtained from irrigated plots of a bare, sandy soil (no vegetation) situated in the Mongolian steppe. Dust flux was measured using the PI-SWERL^(R) device, while soil moisture was measured using gravimetric methods. Our results demonstrate the strong controlling effects of soil moisture on both the threshold friction velocity and dust emission strengths. Threshold friction velocity increased from 0.44 m/s for dry soil (0.002 g/g) to 0.67 m/s for wet soil (0.06 g/g), confirming the importance of soil moisture for controlling dust events. Dust emission strength was significantly depressed for wet soils, starting at a soil moisture value of 0.02 g/g. From these results, we developed a simple dust diagram that may be useful as part of a warning system to identify initial sensitivity to threshold conditions as well as conditions that could lead to potentially significant dust emissions. Overall, the research findings in this study could be used to provide foreknowledge of conditions that would be conducive to high dust emissions for this area of Mongolia.展开更多
基金Natural Science Foundation of Jiangsu Province(BK20160223)。
文摘The principle of improving the torque amplification factor of E-TVDs with six elements is illustrated in this paper.A velocity diagram is used to study speed and torque relationships.The results reveal that the torque amplification factor is the linear combination of the ratio of the differentials of the four elements and the ratio of planetary gear units,and its maximum value is easily more than 10.The E-TVDs with six elements are classified into three types,and there are six different configurations for each type.The torque amplification factor and the speed of interconnection between two planetary gear units are employed to evaluate the different characteristics of each E-TVD with six elements.The feasible configurations of a differential with four elements are also presented by the analysis of velocity level and planarity.This paper helps to further the understanding of the complex interconnection of the planetary gear units in E-TVDs with six elements and the differences of their characteristics.
基金supported by the School Foundation of Changzhou University(Grant No.ZMF1002121)
文摘High-precision proper motions and radial velocities of 1046 stars are used to determine member stars using three-dimensional (3D) kinematics for open clus- ter NGC 188 based on the density-based spatial clustering of applications with noise (DBSCAN) clustering algorithm. By implementing this algorithm, 472 member stars in the cluster are obtained with 3D kinematics. The color-magnitude diagram (CMD) of the 472 member stars using 3D kinematics shows a well-defined main sequence and a red giant branch, which indicate that the DBSCAN clustering algorithm is very effective for membership determination. The DBSCAN clustering algorithm can ef- fectively select probable member stars in 3D kinematic space without any assumption about the distribution of the cluster or field stars. Analysis results show that the CMD of member stars is significantly clearer than the one based on 2D kinematics, which al- lows us to better constrain the cluster members and estimate their physical parameters. Using the 472 member stars, the average absolute proper motion and radial velocity are determined to be (PMα, PMδ) = (-2.58 ± 0.22, +0.17 ± 0.18) mas yr-1 and Vr = -42.35 ± 0.05 km s-1, respectively. Our values are in good agreement with values derived by other authors.
文摘This study presents experimental results of the change in threshold friction velocity and dust emission strength as a function of soil moisture content. The dust and soil moisture data were obtained from irrigated plots of a bare, sandy soil (no vegetation) situated in the Mongolian steppe. Dust flux was measured using the PI-SWERL^(R) device, while soil moisture was measured using gravimetric methods. Our results demonstrate the strong controlling effects of soil moisture on both the threshold friction velocity and dust emission strengths. Threshold friction velocity increased from 0.44 m/s for dry soil (0.002 g/g) to 0.67 m/s for wet soil (0.06 g/g), confirming the importance of soil moisture for controlling dust events. Dust emission strength was significantly depressed for wet soils, starting at a soil moisture value of 0.02 g/g. From these results, we developed a simple dust diagram that may be useful as part of a warning system to identify initial sensitivity to threshold conditions as well as conditions that could lead to potentially significant dust emissions. Overall, the research findings in this study could be used to provide foreknowledge of conditions that would be conducive to high dust emissions for this area of Mongolia.