This paper deals with the initial-boundary value mixed problems for nonlinear wave equations. By introducing the 'blowing-up facts K(u,u_i)', We may discuss the blowing up behaviours of solutions in finite tim...This paper deals with the initial-boundary value mixed problems for nonlinear wave equations. By introducing the 'blowing-up facts K(u,u_i)', We may discuss the blowing up behaviours of solutions in finite time to the mixed problems with respect to Neumann boundary and Dirichlet boundary for various nonlinear conditions and initial value conditions which usually meet.展开更多
Surface displacement caused by underground coal mining is influenced by many factors such as the depth and thickness of the coal seam and joints in overburben rocks. Extensive efforts have been devoted to the ground s...Surface displacement caused by underground coal mining is influenced by many factors such as the depth and thickness of the coal seam and joints in overburben rocks. Extensive efforts have been devoted to the ground surface displacement. Nevertheless, the joints have not been taken into consideration for a long time. In fact, there exist numerous joints and cracks in rocks.As a result, the joints in overburden rocks have to be taken into account. The joints in rocks can be treated as initial damage theoretically. In this paper, two kinds of physical model, one containing no initial joints and anotber containing some initial joints, are employed to systematically investigate effecs of initial joints on surface subsidence. Moreover, within the framework of damage mechanics, the statistical relationships between the characteristic value for surface displacement and damage variable are obtained.展开更多
Experiments were conducted in a U-shaped open-channel flume with the intention of investigating the bursting phenomena in the meander channel. The experimental results of the secondary flow fields and the Reynolds she...Experiments were conducted in a U-shaped open-channel flume with the intention of investigating the bursting phenomena in the meander channel. The experimental results of the secondary flow fields and the Reynolds shear stress distributions show that the velocity and velocity fluctuation in the transverse direction are not negligible. Moreover, the bursting process is investigated using the three-dimensional quadrant analysis, which is more accurate than using the traditional two-dimensional quadrant analysis for the meandering channel. It is obtained from the experimental results that the internal group of events occurs more frequently than the external group, particularly the internal ejection and internal sweep events. In addition, the transition probabilities of the movements, which are defined as the changes of events from the current situation to the next situation in a time series, show that the stable organizations of events are the most possible movements, whereas the cross organizations of events have the least possible movements.展开更多
On the basis of ANSYS finite element model(FEM) software, the deep-level rockburst in Fuxin coalfield was simulated numerically. Based on Haizhou Mine and Wulong Mine as two typical deep-level rockburst examples in Fu...On the basis of ANSYS finite element model(FEM) software, the deep-level rockburst in Fuxin coalfield was simulated numerically. Based on Haizhou Mine and Wulong Mine as two typical deep-level rockburst examples in Fuxin coalfield, the rules and characteristics of the deep-level rockburst were analyzed. And the models were es- tablished. For Haizhou mine, the relationship between mining distance and rockburst was presented when 100, 300, 600 m were mined in 3313 working face. When 300 m were mined, the rockburst began to emerge. When 600 m were mined, the rockburst was the most possible to happen and the compression stress of the working face reached to the maximum value. The effect of tectonic stress on synclinal axis is also a key factor to rockburst occurrence. This was verified by the rockburst happened when 496 m were mined. For Wulong mine, based on the 311 working face as an example, the contours of Y stress in the roof and floor were obtained when the mining distance were 100, 200, 300 and 400 m. When 100 and 400 m were mined, the high stress con- centration regions occurred in the front of working face. This shows the rockburst is easy to happen. It is confirmed by the rockburst when 91m were mined in 311 working plane. The above indicates that the numerical simulation has instructive rule to study the deep-level rockburst in Fuxin coalfield.展开更多
This discussion paper is an attempt to consider new ideas about the nature of explosive phenomena of the meteorite bodies in the Earth＇s atmosphere. Authors attract approaches, based on the concepts of physics of com...This discussion paper is an attempt to consider new ideas about the nature of explosive phenomena of the meteorite bodies in the Earth＇s atmosphere. Authors attract approaches, based on the concepts of physics of combustion, explosion and detonation in order to explain the explosive collapse of the meteorite. Authors believe that the meteorite explosion may be the result of gas-detonation mechanism of overheated meteoric bodies explosive boiling-up （the ＂vapor explosion＂）, accompanied by the formation of a supersonic front of shock wave. The considered hypothesis regarding the role of the ＂vapor explosion＂ in geological disasters can be used to explain the mechanisms of explosive phenomena in Volcanology： （1） With respect to the description of nature of phreatic eruptions; （2） for interpretation of dynamic regularities of the volcano crater opening and the subsequent shock-wave emission of steam-gas ＂fountain＂ to a height of several kilometers with fragments of magma and rocks as a result of the ＂vapor explosion＂ of overheated magma mass under the dome of the volcano.展开更多
This paper presents a study on the criterion of crack initiation and propagation under creep conditions, which were investigated using specimens collected from outcropped sandstone rock formations. Beam specimens unde...This paper presents a study on the criterion of crack initiation and propagation under creep conditions, which were investigated using specimens collected from outcropped sandstone rock formations. Beam specimens under three points bending were used in this investigation. The experimental result shows that due to creep deformation, rock crack will inevitably initiate and propagate after a time interval of sustained loading under a load of K I , which is less than fracture toughness K IC but not less than a constant marked as K IC2 . K IC2 indicates the ability of rock to resist crack initiation and propagation under creep conditions and it is defined as creep fracture toughness.展开更多
The phenomenon of data explosion represents a severe challenge for the upcoming big data era.However,the current Internet architecture is insufficient for dealing with a huge amount of traffic owing to an increase in ...The phenomenon of data explosion represents a severe challenge for the upcoming big data era.However,the current Internet architecture is insufficient for dealing with a huge amount of traffic owing to an increase in redundant content transmission and the end-point-based communication model.Information-centric networking(ICN)is a paradigm for the future Internet that can be utilized to resolve the data explosion problem.In this paper,we focus on content-centric networking(CCN),one of the key candidate ICN architectures.CCN has been studied in various network environments with the aim of relieving network and server burden,especially in name-based forwarding and in-network caching functionalities.This paper studies the effect of several caching strategies in the CCN domain from the perspective of network and server overhead.Thus,we comprehensively analyze the in-network caching performance of CCN under several popular cache replication methods(i.e.,cache placement).We evaluate the performance with respect to wellknown Internet traffic patterns that follow certain probabilistic distributions,such as the Zipf/Mandelbrot–Zipf distributions,and flashcrowds.For the experiments,we developed an OPNET-based CCN simulator with a realistic Internet-like topology.展开更多
The main purpose of the paper is to display the relaxation oscillations, known as the bursting phenomena, for the coupled oscillators with periodic excitation with an order gap between the exciting frequency and the n...The main purpose of the paper is to display the relaxation oscillations, known as the bursting phenomena, for the coupled oscillators with periodic excitation with an order gap between the exciting frequency and the natural frequency. For the case when the exciting frequency is much smaller than the natural frequency, different types of bursting oscillations such as fold/fold, Hopf/Hopf bursting oscillations can be observed. By regarding the whole exciting term as a slow-varying parameter on the fact that the exciting term changes on a much smaller time scale, bifurcations sets of the generalized autonomous system is derived, which divide the parameter space into several regions associated with different types of dynamical behaviors. Two cases with typical bifurcation patterns are focused on as examples to explore the dynamical evolution with the variation of the amplitude of the external excitation. Bursting oscillations which alternate between quiescent states (QSs) and repetitive spiking states (SPs) can be obtained, the mechanism of which is presented by introducing the transformed phase portraits overlapping with the bifurcation diagrams of the generalized autonomous system. It is found that not only the forms of QSs and SPs, but also the bifurcations at the transition points between QSs and SPs, may influence the structures of bursting attractors. Furthermore, the amplitudes and the frequencies related to SPs may depend on the bifurcation patterns from the quiescent sates.展开更多
Addressed here is the occurrence of point singularities which owe to the focusing of short or long waves, a phenomenon labeled dispersive blow-up. The context of this investigation is linear and nonlinear, strongly di...Addressed here is the occurrence of point singularities which owe to the focusing of short or long waves, a phenomenon labeled dispersive blow-up. The context of this investigation is linear and nonlinear, strongly dispersive equations or systems of equations. The present essay deals with linear and nonlinear Schrdinger equations, a class of fractional order Schrdinger equations and the linearized water wave equations, with and without surface tension. Commentary about how the results may bear upon the formation of rogue waves in fluid and optical environments is also included.展开更多
文摘This paper deals with the initial-boundary value mixed problems for nonlinear wave equations. By introducing the 'blowing-up facts K(u,u_i)', We may discuss the blowing up behaviours of solutions in finite time to the mixed problems with respect to Neumann boundary and Dirichlet boundary for various nonlinear conditions and initial value conditions which usually meet.
文摘Surface displacement caused by underground coal mining is influenced by many factors such as the depth and thickness of the coal seam and joints in overburben rocks. Extensive efforts have been devoted to the ground surface displacement. Nevertheless, the joints have not been taken into consideration for a long time. In fact, there exist numerous joints and cracks in rocks.As a result, the joints in overburden rocks have to be taken into account. The joints in rocks can be treated as initial damage theoretically. In this paper, two kinds of physical model, one containing no initial joints and anotber containing some initial joints, are employed to systematically investigate effecs of initial joints on surface subsidence. Moreover, within the framework of damage mechanics, the statistical relationships between the characteristic value for surface displacement and damage variable are obtained.
基金Supported by National Natural Science Foundation of China(No.50979066 and No.51279124)Foundation for Creative Research Groups of National Natural Science Foundation of China(No.51021004)
文摘Experiments were conducted in a U-shaped open-channel flume with the intention of investigating the bursting phenomena in the meander channel. The experimental results of the secondary flow fields and the Reynolds shear stress distributions show that the velocity and velocity fluctuation in the transverse direction are not negligible. Moreover, the bursting process is investigated using the three-dimensional quadrant analysis, which is more accurate than using the traditional two-dimensional quadrant analysis for the meandering channel. It is obtained from the experimental results that the internal group of events occurs more frequently than the external group, particularly the internal ejection and internal sweep events. In addition, the transition probabilities of the movements, which are defined as the changes of events from the current situation to the next situation in a time series, show that the stable organizations of events are the most possible movements, whereas the cross organizations of events have the least possible movements.
基金Supported by National Nature Science Foundation of China (50490275)
文摘On the basis of ANSYS finite element model(FEM) software, the deep-level rockburst in Fuxin coalfield was simulated numerically. Based on Haizhou Mine and Wulong Mine as two typical deep-level rockburst examples in Fuxin coalfield, the rules and characteristics of the deep-level rockburst were analyzed. And the models were es- tablished. For Haizhou mine, the relationship between mining distance and rockburst was presented when 100, 300, 600 m were mined in 3313 working face. When 300 m were mined, the rockburst began to emerge. When 600 m were mined, the rockburst was the most possible to happen and the compression stress of the working face reached to the maximum value. The effect of tectonic stress on synclinal axis is also a key factor to rockburst occurrence. This was verified by the rockburst happened when 496 m were mined. For Wulong mine, based on the 311 working face as an example, the contours of Y stress in the roof and floor were obtained when the mining distance were 100, 200, 300 and 400 m. When 100 and 400 m were mined, the high stress con- centration regions occurred in the front of working face. This shows the rockburst is easy to happen. It is confirmed by the rockburst when 91m were mined in 311 working plane. The above indicates that the numerical simulation has instructive rule to study the deep-level rockburst in Fuxin coalfield.
文摘This discussion paper is an attempt to consider new ideas about the nature of explosive phenomena of the meteorite bodies in the Earth＇s atmosphere. Authors attract approaches, based on the concepts of physics of combustion, explosion and detonation in order to explain the explosive collapse of the meteorite. Authors believe that the meteorite explosion may be the result of gas-detonation mechanism of overheated meteoric bodies explosive boiling-up （the ＂vapor explosion＂）, accompanied by the formation of a supersonic front of shock wave. The considered hypothesis regarding the role of the ＂vapor explosion＂ in geological disasters can be used to explain the mechanisms of explosive phenomena in Volcanology： （1） With respect to the description of nature of phreatic eruptions; （2） for interpretation of dynamic regularities of the volcano crater opening and the subsequent shock-wave emission of steam-gas ＂fountain＂ to a height of several kilometers with fragments of magma and rocks as a result of the ＂vapor explosion＂ of overheated magma mass under the dome of the volcano.
文摘This paper presents a study on the criterion of crack initiation and propagation under creep conditions, which were investigated using specimens collected from outcropped sandstone rock formations. Beam specimens under three points bending were used in this investigation. The experimental result shows that due to creep deformation, rock crack will inevitably initiate and propagate after a time interval of sustained loading under a load of K I , which is less than fracture toughness K IC but not less than a constant marked as K IC2 . K IC2 indicates the ability of rock to resist crack initiation and propagation under creep conditions and it is defined as creep fracture toughness.
基金supported by Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(2014R1A1A2057796)and(2015R1D1A1A01059049)
文摘The phenomenon of data explosion represents a severe challenge for the upcoming big data era.However,the current Internet architecture is insufficient for dealing with a huge amount of traffic owing to an increase in redundant content transmission and the end-point-based communication model.Information-centric networking(ICN)is a paradigm for the future Internet that can be utilized to resolve the data explosion problem.In this paper,we focus on content-centric networking(CCN),one of the key candidate ICN architectures.CCN has been studied in various network environments with the aim of relieving network and server burden,especially in name-based forwarding and in-network caching functionalities.This paper studies the effect of several caching strategies in the CCN domain from the perspective of network and server overhead.Thus,we comprehensively analyze the in-network caching performance of CCN under several popular cache replication methods(i.e.,cache placement).We evaluate the performance with respect to wellknown Internet traffic patterns that follow certain probabilistic distributions,such as the Zipf/Mandelbrot–Zipf distributions,and flashcrowds.For the experiments,we developed an OPNET-based CCN simulator with a realistic Internet-like topology.
基金supported by the National Natural Science Foundation of China (Grant Nos. 11272135, 21276115, 11472115 & 11472116)the Scientific Research Innovation Foundation of Jiangsu Province (Grant No.1291480004)
文摘The main purpose of the paper is to display the relaxation oscillations, known as the bursting phenomena, for the coupled oscillators with periodic excitation with an order gap between the exciting frequency and the natural frequency. For the case when the exciting frequency is much smaller than the natural frequency, different types of bursting oscillations such as fold/fold, Hopf/Hopf bursting oscillations can be observed. By regarding the whole exciting term as a slow-varying parameter on the fact that the exciting term changes on a much smaller time scale, bifurcations sets of the generalized autonomous system is derived, which divide the parameter space into several regions associated with different types of dynamical behaviors. Two cases with typical bifurcation patterns are focused on as examples to explore the dynamical evolution with the variation of the amplitude of the external excitation. Bursting oscillations which alternate between quiescent states (QSs) and repetitive spiking states (SPs) can be obtained, the mechanism of which is presented by introducing the transformed phase portraits overlapping with the bifurcation diagrams of the generalized autonomous system. It is found that not only the forms of QSs and SPs, but also the bifurcations at the transition points between QSs and SPs, may influence the structures of bursting attractors. Furthermore, the amplitudes and the frequencies related to SPs may depend on the bifurcation patterns from the quiescent sates.
基金supported by the Agence Nationale de la Recherche, France (No. ANR-07-BLAN-0250)the University of Illinois at Chicago,the Wolfgang Pauli Institute in Vienna, the University of Illinois at Chicago and the Université de Paris 11
文摘Addressed here is the occurrence of point singularities which owe to the focusing of short or long waves, a phenomenon labeled dispersive blow-up. The context of this investigation is linear and nonlinear, strongly dispersive equations or systems of equations. The present essay deals with linear and nonlinear Schrdinger equations, a class of fractional order Schrdinger equations and the linearized water wave equations, with and without surface tension. Commentary about how the results may bear upon the formation of rogue waves in fluid and optical environments is also included.
