Segmenting blurred and conglutinated bubbles in a flotation image is done using a new segmentation method based on Seed Region and Boundary Growing（SRBG）.Bright pixels located on bubble tops were extracted as the se...Segmenting blurred and conglutinated bubbles in a flotation image is done using a new segmentation method based on Seed Region and Boundary Growing（SRBG）.Bright pixels located on bubble tops were extracted as the seed regions.Seed boundaries are divided into four curves：left-top,right-top,right-bottom, and left-bottom.Bubbles are segmented from the seed boundary by moving these curves to the bubble boundaries along the corresponding directions.The SRBG method can remove noisy areas and it avoids over- and under-segmentation problems.Each bubble is segmented separately rather than segmenting the entire flotation image.The segmentation results from the SRBG method are more accurate than those from the Watershed algorithm.展开更多
In this paper we discuss the seismogenic structures of the two earthquakes occurring in the Beibu Gulf waters,based on the investigation of geological structure,faults,geophysical fields,seismicity and earthquake foca...In this paper we discuss the seismogenic structures of the two earthquakes occurring in the Beibu Gulf waters,based on the investigation of geological structure,faults,geophysical fields,seismicity and earthquake focal mechanism.The results show that the NEE trending faults along the boundary of the Wushi depression are the dominating seismogenic structures,and the NW trending faults are the key factors of stress concentration.The results also show that high seismicity has a significant relationship with the late Cenozoic deposition center in the Beibu Gulf,and their NE-NEE trending boundary faults are important to the identification of seismogenic structures.The special arcuate fault segment or the intersection point of the NW trending faults and NE-NEE trending boundary faults is a possible location of future earthquakes.展开更多
Mathematical models of propellers were created that investigate the influence of periodic boundary conditions on predictions of a propeller's performance.Thrust and torque coefficients corresponding to different a...Mathematical models of propellers were created that investigate the influence of periodic boundary conditions on predictions of a propeller's performance.Thrust and torque coefficients corresponding to different advance coefficients of DTMB 4119, 4382, and 4384 propellers were calculated.The pressure coefficient distribution of the DTMB 4119 propeller at different sections was also physically tested.Comparisons indicated good agreement between the results of experiments and the simulation.It showed that the periodic boundary condition can be used to rationally predict the open water performance of a propeller.By analyzing the three established modes for the computation, it was shown that using the spline curve method to divide the grids can meet the calculation's demands for precision better than using the rake cutting method.展开更多
基金supported in part by the National Science & Technology Support Plan of China(No.2009BAB48B02)
文摘Segmenting blurred and conglutinated bubbles in a flotation image is done using a new segmentation method based on Seed Region and Boundary Growing（SRBG）.Bright pixels located on bubble tops were extracted as the seed regions.Seed boundaries are divided into four curves：left-top,right-top,right-bottom, and left-bottom.Bubbles are segmented from the seed boundary by moving these curves to the bubble boundaries along the corresponding directions.The SRBG method can remove noisy areas and it avoids over- and under-segmentation problems.Each bubble is segmented separately rather than segmenting the entire flotation image.The segmentation results from the SRBG method are more accurate than those from the Watershed algorithm.
基金funded under the special project of earthquake study(200708003) under the National Key Technology R&D Program (2006BAC13B01),China
文摘In this paper we discuss the seismogenic structures of the two earthquakes occurring in the Beibu Gulf waters,based on the investigation of geological structure,faults,geophysical fields,seismicity and earthquake focal mechanism.The results show that the NEE trending faults along the boundary of the Wushi depression are the dominating seismogenic structures,and the NW trending faults are the key factors of stress concentration.The results also show that high seismicity has a significant relationship with the late Cenozoic deposition center in the Beibu Gulf,and their NE-NEE trending boundary faults are important to the identification of seismogenic structures.The special arcuate fault segment or the intersection point of the NW trending faults and NE-NEE trending boundary faults is a possible location of future earthquakes.
基金Supported by the National Natural Science Foundation of China under Grant No.10702016
文摘Mathematical models of propellers were created that investigate the influence of periodic boundary conditions on predictions of a propeller's performance.Thrust and torque coefficients corresponding to different advance coefficients of DTMB 4119, 4382, and 4384 propellers were calculated.The pressure coefficient distribution of the DTMB 4119 propeller at different sections was also physically tested.Comparisons indicated good agreement between the results of experiments and the simulation.It showed that the periodic boundary condition can be used to rationally predict the open water performance of a propeller.By analyzing the three established modes for the computation, it was shown that using the spline curve method to divide the grids can meet the calculation's demands for precision better than using the rake cutting method.
