Landslide is one of the multitudinous serious geological hazards. The key to its control and reduction lies on dynamic monitoring and early warning. The article points out the insufficiency of traditional measuring me...Landslide is one of the multitudinous serious geological hazards. The key to its control and reduction lies on dynamic monitoring and early warning. The article points out the insufficiency of traditional measuring means applied for large-scale landslide monitoring and proposes the method for extensive landslide displacement field monitoring using high- resolution remote images. Matching of cognominal points is realized by using the invariant features of SIFT algorithm in image translation, rotation, zooming, and affine transformation, and through recognition and comparison of characteristics of high-resolution images in different landsliding periods. Following that, landslide displacement vector field can be made known by measuring the distances and directions between cognominal points. As evidenced by field application of the method for landslide monitoring at West Open Mine in Fushun city of China, the method has the attraction of being able to make areal measurement through satellite observation and capable of obtaining at the same time the information of large- area intensive displacement field, for facilitating automatic delimitation of extent of landslide displacement vector field and sliding mass. This can serve as a basis for making analysis of laws governing occurrence of landslide and adoption of countermeasures.展开更多
Abstract：ools. The effective strain rate for for determining the total pressure developed during forging of a rectangular bar forging with bulging was expressed in terms of four-dimensional strain rate vector. The in...Abstract：ools. The effective strain rate for for determining the total pressure developed during forging of a rectangular bar forging with bulging was expressed in terms of four-dimensional strain rate vector. The inner-product of the vector was termwise integrated and summed. The integral mean value theorem was applied to determining the ratio of the strain rate components and the values of direction cosine of the vector and then an analytical solution of stress effective factor was obtained. The compression experiments of pure lead bar were performed to test the accuracy of the solution. The optimized results of total pressure by golden section search were compared with those of the indicator readings of the testing machine. It indicates that the optimized total pressures are 2.60%-10.14% higher than those measured. The solution is available and still an upper-bound solution.展开更多
A heavy-rainfall event that occurred in North China during 19–20 July 2016,resulting in severe flooding,was investigated in this study.In this event,high-value total deformation overlapped the precipitation region,im...A heavy-rainfall event that occurred in North China during 19–20 July 2016,resulting in severe flooding,was investigated in this study.In this event,high-value total deformation overlapped the precipitation region,implying a close relationship between them.By deriving the nongeostrophicωequation in a non-uniformly saturated moist atmosphere,the relation between vertical velocity and deformation was diagnosed.The Q-vector divergence on the right-hand side of the newωequation was divided into three compositions,associated with horizontal divergence,vertical vorticity,and horizontal-wind deformation,respectively.It was found that the deformation component of Q-vector divergence contributed most to the negative Q-vector divergence in the precipitation region,implying an important role of deformation forcing in facilitating the vertical motion.In order to track the precipitation on the basis of deformation,potential deformation was proposed by virtue of the generalized potential temperature.The high-value potential deformation and precipitation were always overlapping,and shared an analogous temporal trend.This means that potential deformation can reflect the variation of heavy precipitation to a certain extent,and can serve as a tracker of the precipitation region.展开更多
This paper demonstrates that,for a moist baroclinic frontal system,the large-value deformation belt in the low-level atmosphere overlaps with precipitation.To precisely describe the relationship between deformation an...This paper demonstrates that,for a moist baroclinic frontal system,the large-value deformation belt in the low-level atmosphere overlaps with precipitation.To precisely describe the relationship between deformation and heavy precipitation,deformation is introduced into the nongeostrophic Q^#-vector.Q^#is then decomposed into three parts:the divergence-related term,the vorticity-related term,and the deformation-related term.By calculating the divergence of Q#and its components,it is found that in strong ascending areas within precipitation regions the nongeostrophic Q^#-vector divergence shows strong negative values.Its deformational component can contribute about 68%to these negative values.This verifies that strong deformation in a precipitating atmosphere is favorable for the development of convection and precipitation.In addition,by calculating the correlation coefficients between the Q^#-vector(including its components)divergence and vertical motions,it is also found that the Q^#-vector divergence shows higher correlation with vertical motion within the precipitation belt and lower correlation in the non-precipitation areas,which indicates a larger contribution of Q^#to vertical motion when precipitation occurs and implies an effect of Q^#to the precipitation distribution or spatial variability.Among the three components of the Q^#-vector,the correlation coefficients between the deformational component and vertical motion are the most similar in pattern to that of the correlation coefficients between the Q#-vector and vertical motion,which further reflects the important contribution of deformation to the large spatial variability of precipitation.展开更多
The deformation of landslide is usually expressed in horizontal and vertical direction separately. Based on the X, Y, Z coor-dinates from a real monitoring project, a method to build three-dimensional(3D) model of lan...The deformation of landslide is usually expressed in horizontal and vertical direction separately. Based on the X, Y, Z coor-dinates from a real monitoring project, a method to build three-dimensional(3D) model of landslide by constructing triangulated ir-regular network (TIN) and extruding contour lines is proposed. The almost imperceptible displacements of monitoring points are zoomed by two kind of exaggerating methods. The deformation process is replayed using 3D animation technique.展开更多
This paper gives the existence of a relatively stable duck solution in a slow-fast system in R2＋2 with an invariant manifold. The slow-fast system in R2＋： has a 2-dimensional slow vector field and a 2-dimensional f...This paper gives the existence of a relatively stable duck solution in a slow-fast system in R2＋2 with an invariant manifold. The slow-fast system in R2＋： has a 2-dimensional slow vector field and a 2-dimensional fast vector field. The fast vector field restricts a feasible region of the slow vector field strictly. In the case of the slow-fast system in R2＋1 , that is, the fast vector field is l-dimension, it is classified according to its sign, because it gives only negative（-）, positive（＋） or zero sign. Then it is attractive, repulsive or stationary. On the other hand, in R2~2 , the fast vector field has combinatorial cases. It causes a complex state to analyze the system. First, we introduce a local model near the pseudo singular point on which we classify the fast vector field attractive（-,-）, attractive-repulsive（-,＋） or repulsive（＋,＋）, simply as possible. We prove the existence of a 4-dimensional duck solution in the local model. Secondarily, we assume that the slow-fast system has an invariant manifold near the pseudo singular point. When the invariant manifold has a homoclinic point near the pseudo singular point, we show that the slow-fast sytem has a 4-dimensional duck solution having a relatively stable region.展开更多
文摘Landslide is one of the multitudinous serious geological hazards. The key to its control and reduction lies on dynamic monitoring and early warning. The article points out the insufficiency of traditional measuring means applied for large-scale landslide monitoring and proposes the method for extensive landslide displacement field monitoring using high- resolution remote images. Matching of cognominal points is realized by using the invariant features of SIFT algorithm in image translation, rotation, zooming, and affine transformation, and through recognition and comparison of characteristics of high-resolution images in different landsliding periods. Following that, landslide displacement vector field can be made known by measuring the distances and directions between cognominal points. As evidenced by field application of the method for landslide monitoring at West Open Mine in Fushun city of China, the method has the attraction of being able to make areal measurement through satellite observation and capable of obtaining at the same time the information of large- area intensive displacement field, for facilitating automatic delimitation of extent of landslide displacement vector field and sliding mass. This can serve as a basis for making analysis of laws governing occurrence of landslide and adoption of countermeasures.
基金Project(51074052)supported by the National Natural Science Foundation of ChinaProject(20100470676)supported by the China Postdoctoral Science Foundation
文摘Abstract：ools. The effective strain rate for for determining the total pressure developed during forging of a rectangular bar forging with bulging was expressed in terms of four-dimensional strain rate vector. The inner-product of the vector was termwise integrated and summed. The integral mean value theorem was applied to determining the ratio of the strain rate components and the values of direction cosine of the vector and then an analytical solution of stress effective factor was obtained. The compression experiments of pure lead bar were performed to test the accuracy of the solution. The optimized results of total pressure by golden section search were compared with those of the indicator readings of the testing machine. It indicates that the optimized total pressures are 2.60%-10.14% higher than those measured. The solution is available and still an upper-bound solution.
基金supported by the Strategic Pilot Science and Technology Special Program of the Chinese Academy of Sciences(XDA17010105)the Special Scientific Research Fund of the Meteorological Public Welfare of the Ministry of Sciences and Technology(GYHY201406002)+2 种基金the Science and Technology Project of Guangzhou(201604020069)the National Natural Science Foundation of China(41505040,41575065,and 4177510)the Open Projects of the Plateau Atmosphere and Environment Key Laboratory of Sichuan Province(PAEKL-2015-K2)
文摘A heavy-rainfall event that occurred in North China during 19–20 July 2016,resulting in severe flooding,was investigated in this study.In this event,high-value total deformation overlapped the precipitation region,implying a close relationship between them.By deriving the nongeostrophicωequation in a non-uniformly saturated moist atmosphere,the relation between vertical velocity and deformation was diagnosed.The Q-vector divergence on the right-hand side of the newωequation was divided into three compositions,associated with horizontal divergence,vertical vorticity,and horizontal-wind deformation,respectively.It was found that the deformation component of Q-vector divergence contributed most to the negative Q-vector divergence in the precipitation region,implying an important role of deformation forcing in facilitating the vertical motion.In order to track the precipitation on the basis of deformation,potential deformation was proposed by virtue of the generalized potential temperature.The high-value potential deformation and precipitation were always overlapping,and shared an analogous temporal trend.This means that potential deformation can reflect the variation of heavy precipitation to a certain extent,and can serve as a tracker of the precipitation region.
基金supported by the National Basic Key Research Program of China(Grant No.2015CB452804)the National Key Technology Research and Development Program of China(Grant No.2015BAC03B04)+2 种基金the National Natural Science Foundation of China(Grant Nos.41505040,91437215,41575047,41575065,4177510)the Open Projects of the Plateau Atmosphere and Environment Key Laboratory of Sichuan Province(Grant No.PAEKL-2015-K2)the Guangzhou Science and Technology Planning Project(201604020069)
文摘This paper demonstrates that,for a moist baroclinic frontal system,the large-value deformation belt in the low-level atmosphere overlaps with precipitation.To precisely describe the relationship between deformation and heavy precipitation,deformation is introduced into the nongeostrophic Q^#-vector.Q^#is then decomposed into three parts:the divergence-related term,the vorticity-related term,and the deformation-related term.By calculating the divergence of Q#and its components,it is found that in strong ascending areas within precipitation regions the nongeostrophic Q^#-vector divergence shows strong negative values.Its deformational component can contribute about 68%to these negative values.This verifies that strong deformation in a precipitating atmosphere is favorable for the development of convection and precipitation.In addition,by calculating the correlation coefficients between the Q^#-vector(including its components)divergence and vertical motions,it is also found that the Q^#-vector divergence shows higher correlation with vertical motion within the precipitation belt and lower correlation in the non-precipitation areas,which indicates a larger contribution of Q^#to vertical motion when precipitation occurs and implies an effect of Q^#to the precipitation distribution or spatial variability.Among the three components of the Q^#-vector,the correlation coefficients between the deformational component and vertical motion are the most similar in pattern to that of the correlation coefficients between the Q#-vector and vertical motion,which further reflects the important contribution of deformation to the large spatial variability of precipitation.
文摘The deformation of landslide is usually expressed in horizontal and vertical direction separately. Based on the X, Y, Z coor-dinates from a real monitoring project, a method to build three-dimensional(3D) model of landslide by constructing triangulated ir-regular network (TIN) and extruding contour lines is proposed. The almost imperceptible displacements of monitoring points are zoomed by two kind of exaggerating methods. The deformation process is replayed using 3D animation technique.
文摘This paper gives the existence of a relatively stable duck solution in a slow-fast system in R2＋2 with an invariant manifold. The slow-fast system in R2＋： has a 2-dimensional slow vector field and a 2-dimensional fast vector field. The fast vector field restricts a feasible region of the slow vector field strictly. In the case of the slow-fast system in R2＋1 , that is, the fast vector field is l-dimension, it is classified according to its sign, because it gives only negative（-）, positive（＋） or zero sign. Then it is attractive, repulsive or stationary. On the other hand, in R2~2 , the fast vector field has combinatorial cases. It causes a complex state to analyze the system. First, we introduce a local model near the pseudo singular point on which we classify the fast vector field attractive（-,-）, attractive-repulsive（-,＋） or repulsive（＋,＋）, simply as possible. We prove the existence of a 4-dimensional duck solution in the local model. Secondarily, we assume that the slow-fast system has an invariant manifold near the pseudo singular point. When the invariant manifold has a homoclinic point near the pseudo singular point, we show that the slow-fast sytem has a 4-dimensional duck solution having a relatively stable region.
