The Tongchang orefield is located in the central part of the Mianxian-Lueyang-Yangpingguan area that is celebrated as a 'gold triangle' area,at the juncture of the latitudinal tectonic zone of South Qinling,th...The Tongchang orefield is located in the central part of the Mianxian-Lueyang-Yangpingguan area that is celebrated as a 'gold triangle' area,at the juncture of the latitudinal tectonic zone of South Qinling,the Longmenshan Cathysian tectonic zone and the Sichuan-Yunnan longitudinal tectonic zone,where there are distributed Cu-Au polymetallic ore deposits(occurrences) including the Tongchang,Chenjiaba,Qinjiabian,Hongtushi,Yinshangou and Xiakouyi ore deposits(mineralization).Based on the "giant pressure shadow" structure put forward and demonstrated by numerical modeling of the tectonic stress field and the static photoelasticity experiments on the basis of tectonic ore-controlling laws in the orefield,tectonic metallogenesis driven by orefield tectonic stress has been discussed in terms of its geological setting,orefield geomechanics,and tectonic stress field.It is thought that the dynamic evolution model of the tectonic stress field controls the whole process of formation of the polymetallic ore deposits(mineralization) in the orefield,as well as the deformation field.As a result,it controls the emplacement of rockbodies and the transformation of ore-source bodies,and provides both the channel-ways for ore-forming fluids and ore-hosting space.Furthermore,it controls the migration potential field of fluids and,thereafter,its flow direction,rate and volume;the tectonic stress field also controls the energy field and hence controls the position of occurrence of ore deposits and their scale.The method of tectonic stress field has been applied to ore prognosis in the orefield.The rules of magmatic emplacement and metallogenic fluid migrating and concentrating under the control of the structural stress field were expounded,hence providing the theoretical basis for the prognosis of concealed ores.In addition,a number of important target areas have been defined.展开更多
Shadow and variable illumination considerably influence the results of image understanding such as image segmentation, object tracking, and object recognition. The intrinsic image decomposition is to separate the refl...Shadow and variable illumination considerably influence the results of image understanding such as image segmentation, object tracking, and object recognition. The intrinsic image decomposition is to separate the reflectance and the illumination image from an observed image. The intrinsic image decomposition is very useful to remove shadows and then improve the performance of image understanding. In this paper, we present a new shadow removal method based on intrinsic image decomposition on a single color image using the Fisher Linear Discriminant (FLD). Under the assumptions-Lambertian surfaces, approximately Planckian lighting, and narrowband camera sensors, there exist an invariant image, which is 1-dimensional greyscale and independent of illuminant color and intensity. The Fisher Linear Discriminant is applied to create the invariant image. And further the shadows can be removed through the difference between invariant image and original color image. The experimental results on real data show good performance of this algorithm.展开更多
A novel technique for reducing reverberation artifact in acoustic shadow imaging using nonlinear ultrasound interaction, called nonlinear acoustic shadow method, has been developed and experimentally studied. In this ...A novel technique for reducing reverberation artifact in acoustic shadow imaging using nonlinear ultrasound interaction, called nonlinear acoustic shadow method, has been developed and experimentally studied. In this technique, the conventional acoustic shadow method is modified by using the secondary wave generated by nonlinear interaction of two primary sound waves emitted from parametric array. Either conventional or nonlinear acoustic shadow imaging is carried out for aluminum square cylinder and the size of the shadow is compared. The result shows that the nonlinear acoustic shadow method reduces reverberation artifact inside the square cylinder and has better accuracy in the size measurement than conventional acoustic shadow method.展开更多
目的 Linear Programming的simplexmethod建模求最优解。方法应用simplexmethod.结果建立了LinearProgramming的数学模型并用simplexmethod求得了最优解.结论因为单纯形表反映了Linear Programming的所有信息,故用simplexmethod可简便...目的 Linear Programming的simplexmethod建模求最优解。方法应用simplexmethod.结果建立了LinearProgramming的数学模型并用simplexmethod求得了最优解.结论因为单纯形表反映了Linear Programming的所有信息,故用simplexmethod可简便地求得最优解.simplexmethod的基本思路是:先将Linear Programming用sim-plexmethod划为标准型,根据问题的标准型,进行初等行变换,将主元素列除主元素化为1外其余的元素均化为0,当基变量值全为非负时,问题就得到了最优解.展开更多
Pre-driven longwall retracement roadway(PLRR)is commonly used in large mine shaft.The support crushing disasters occur frequently during the retracement,and roof management is necessary.Taking the 31107 panel as resea...Pre-driven longwall retracement roadway(PLRR)is commonly used in large mine shaft.The support crushing disasters occur frequently during the retracement,and roof management is necessary.Taking the 31107 panel as research background,the roof breaking structure of PLRR is analyzed.It is concluded that the roof cutting with vertical hydraulic fracture(HF)at a specified position,that is,fixed-length roof cutting,can reduce support load and keep immediate roof intact.The extended finite element method(XFEM)is applied to simulate hydraulic fracturing.The results show that both the axial and transverse hydraulic fracturing cannot effectively create vertical HFs.Therefore,a novel construction method of vertical HF based on the stress shadow effect(SSE)is proposed.The stress reversal region and HF orientation caused by the prefabricated hydraulic fracture(PF)are verified in simulation.The sub-vertical HFs are obtained between two PFs,the vertical extension range of which is much larger than that of directional hydraulic fracturing.The new construction method was used to determine the field plan for fixed-length roof cutting.The roof formed a stable suspended structure and deformation of the main PLRR was improved after hydraulic fracturing.展开更多
In this paper we show that an -stable diffeomorphism has the weak inverse shadowing property with respect to classes of continuous method and and some of the -stable diffeomorphisms have weak inverse shadowing propert...In this paper we show that an -stable diffeomorphism has the weak inverse shadowing property with respect to classes of continuous method and and some of the -stable diffeomorphisms have weak inverse shadowing property with respect to classes . In addition we study relation between minimality and weak inverse shadowing property with respect to class and relation between expansivity and inverse shadowing property with respect to class .展开更多
A 5-MW wind turbine has been modeled and analyzed for fluid-structure interaction and aerodynamic performance.In this study, a full-scale model of a 5-MW wind turbine is first developed based on a computational fluid ...A 5-MW wind turbine has been modeled and analyzed for fluid-structure interaction and aerodynamic performance.In this study, a full-scale model of a 5-MW wind turbine is first developed based on a computational fluid dynamics(CFD) approach, in which the unsteady, noncompressible Reynolds Averaged Navier-Stokes(RANS) method is used. The main focus of the study is to analyze the tower shadow effect on the aerodynamic performance of the wind turbine under different inlet flow conditions. Subsequently, the finite element model is established by considering fluid/structure interactions to study the structural stress, displacement, strain distributions and flow field information of the structure under the uniform wind speed. Finally, the fluid-structure interaction model is established by considering turbulent wind and the tower shadow effect. The variation rules of the dynamic response of the one-way and two-way fluid-structure interaction(FSI) models under different wind speeds are analyzed, and the numerical calculation results are compared with those of the centralized mass model. The results show that the tower shadow effect and structural deformation are the main factors affecting the aerodynamic load fluctuation of the wind turbine, which in turn affects the aerodynamic performance and structural stability of the blades. The structural dynamic response of the coupled model shows significant similarity, while the structural displacement response of the former exhibits less fluctuation compared with the conventional centralized mass model. The one-way fluid-structure interaction(FSI)model shows a higher frequency of stress-strain and displacement oscillations on the blade compared with the two-way FSI model.展开更多
基金Granted jointly by the Funds for Program for NCET in University (NCET-04-917)NSF (40863002)Project for the Distinguishing Discipline of KUST (2008)
文摘The Tongchang orefield is located in the central part of the Mianxian-Lueyang-Yangpingguan area that is celebrated as a 'gold triangle' area,at the juncture of the latitudinal tectonic zone of South Qinling,the Longmenshan Cathysian tectonic zone and the Sichuan-Yunnan longitudinal tectonic zone,where there are distributed Cu-Au polymetallic ore deposits(occurrences) including the Tongchang,Chenjiaba,Qinjiabian,Hongtushi,Yinshangou and Xiakouyi ore deposits(mineralization).Based on the "giant pressure shadow" structure put forward and demonstrated by numerical modeling of the tectonic stress field and the static photoelasticity experiments on the basis of tectonic ore-controlling laws in the orefield,tectonic metallogenesis driven by orefield tectonic stress has been discussed in terms of its geological setting,orefield geomechanics,and tectonic stress field.It is thought that the dynamic evolution model of the tectonic stress field controls the whole process of formation of the polymetallic ore deposits(mineralization) in the orefield,as well as the deformation field.As a result,it controls the emplacement of rockbodies and the transformation of ore-source bodies,and provides both the channel-ways for ore-forming fluids and ore-hosting space.Furthermore,it controls the migration potential field of fluids and,thereafter,its flow direction,rate and volume;the tectonic stress field also controls the energy field and hence controls the position of occurrence of ore deposits and their scale.The method of tectonic stress field has been applied to ore prognosis in the orefield.The rules of magmatic emplacement and metallogenic fluid migrating and concentrating under the control of the structural stress field were expounded,hence providing the theoretical basis for the prognosis of concealed ores.In addition,a number of important target areas have been defined.
文摘Shadow and variable illumination considerably influence the results of image understanding such as image segmentation, object tracking, and object recognition. The intrinsic image decomposition is to separate the reflectance and the illumination image from an observed image. The intrinsic image decomposition is very useful to remove shadows and then improve the performance of image understanding. In this paper, we present a new shadow removal method based on intrinsic image decomposition on a single color image using the Fisher Linear Discriminant (FLD). Under the assumptions-Lambertian surfaces, approximately Planckian lighting, and narrowband camera sensors, there exist an invariant image, which is 1-dimensional greyscale and independent of illuminant color and intensity. The Fisher Linear Discriminant is applied to create the invariant image. And further the shadows can be removed through the difference between invariant image and original color image. The experimental results on real data show good performance of this algorithm.
文摘A novel technique for reducing reverberation artifact in acoustic shadow imaging using nonlinear ultrasound interaction, called nonlinear acoustic shadow method, has been developed and experimentally studied. In this technique, the conventional acoustic shadow method is modified by using the secondary wave generated by nonlinear interaction of two primary sound waves emitted from parametric array. Either conventional or nonlinear acoustic shadow imaging is carried out for aluminum square cylinder and the size of the shadow is compared. The result shows that the nonlinear acoustic shadow method reduces reverberation artifact inside the square cylinder and has better accuracy in the size measurement than conventional acoustic shadow method.
文摘目的 Linear Programming的simplexmethod建模求最优解。方法应用simplexmethod.结果建立了LinearProgramming的数学模型并用simplexmethod求得了最优解.结论因为单纯形表反映了Linear Programming的所有信息,故用simplexmethod可简便地求得最优解.simplexmethod的基本思路是:先将Linear Programming用sim-plexmethod划为标准型,根据问题的标准型,进行初等行变换,将主元素列除主元素化为1外其余的元素均化为0,当基变量值全为非负时,问题就得到了最优解.
基金financially supported by the Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX21_2358)the National Key Research and Development Program of China(2020YFB1314204)National Natural Science Foundation of China(No.52074239)。
文摘Pre-driven longwall retracement roadway(PLRR)is commonly used in large mine shaft.The support crushing disasters occur frequently during the retracement,and roof management is necessary.Taking the 31107 panel as research background,the roof breaking structure of PLRR is analyzed.It is concluded that the roof cutting with vertical hydraulic fracture(HF)at a specified position,that is,fixed-length roof cutting,can reduce support load and keep immediate roof intact.The extended finite element method(XFEM)is applied to simulate hydraulic fracturing.The results show that both the axial and transverse hydraulic fracturing cannot effectively create vertical HFs.Therefore,a novel construction method of vertical HF based on the stress shadow effect(SSE)is proposed.The stress reversal region and HF orientation caused by the prefabricated hydraulic fracture(PF)are verified in simulation.The sub-vertical HFs are obtained between two PFs,the vertical extension range of which is much larger than that of directional hydraulic fracturing.The new construction method was used to determine the field plan for fixed-length roof cutting.The roof formed a stable suspended structure and deformation of the main PLRR was improved after hydraulic fracturing.
文摘In this paper we show that an -stable diffeomorphism has the weak inverse shadowing property with respect to classes of continuous method and and some of the -stable diffeomorphisms have weak inverse shadowing property with respect to classes . In addition we study relation between minimality and weak inverse shadowing property with respect to class and relation between expansivity and inverse shadowing property with respect to class .
基金supported by the National Natural Science Foundation of China(Grant No.52078010)Beijing Natural Science Foundation(Grant No.JQ19029).
文摘A 5-MW wind turbine has been modeled and analyzed for fluid-structure interaction and aerodynamic performance.In this study, a full-scale model of a 5-MW wind turbine is first developed based on a computational fluid dynamics(CFD) approach, in which the unsteady, noncompressible Reynolds Averaged Navier-Stokes(RANS) method is used. The main focus of the study is to analyze the tower shadow effect on the aerodynamic performance of the wind turbine under different inlet flow conditions. Subsequently, the finite element model is established by considering fluid/structure interactions to study the structural stress, displacement, strain distributions and flow field information of the structure under the uniform wind speed. Finally, the fluid-structure interaction model is established by considering turbulent wind and the tower shadow effect. The variation rules of the dynamic response of the one-way and two-way fluid-structure interaction(FSI) models under different wind speeds are analyzed, and the numerical calculation results are compared with those of the centralized mass model. The results show that the tower shadow effect and structural deformation are the main factors affecting the aerodynamic load fluctuation of the wind turbine, which in turn affects the aerodynamic performance and structural stability of the blades. The structural dynamic response of the coupled model shows significant similarity, while the structural displacement response of the former exhibits less fluctuation compared with the conventional centralized mass model. The one-way fluid-structure interaction(FSI)model shows a higher frequency of stress-strain and displacement oscillations on the blade compared with the two-way FSI model.
