In this paper, we investigate Galton-Watson branching processes in random environments. In the case where the environmental process is a Markov chain which is positive recurrent or has a transition matrix Q (θ,α) su...In this paper, we investigate Galton-Watson branching processes in random environments. In the case where the environmental process is a Markov chain which is positive recurrent or has a transition matrix Q (θ,α) such that sup_θ Q (θ,α)> 0 for some α, we prove that the model has the asymptotic behavior being similar to that of Galton-Watson branching processes. In other case where the environments are non-stationary independent, the sufficient conditions are obtained for certain extinction and uncertain extinction for the model.展开更多
The concepts of Markov process in random environment, q-matrix in random environment, and q-process in random environment are introduced. The minimal q-process in random environment is constructed and the necessary an...The concepts of Markov process in random environment, q-matrix in random environment, and q-process in random environment are introduced. The minimal q-process in random environment is constructed and the necessary and sufficient conditions for the uniqueness of q-process in random environment are given.展开更多
The concepts of bi-immigration birth and death density matrix in random environment and bi-immigration birth and death process in random environment are introduced.For any bi-immigration birth and death matrix in rand...The concepts of bi-immigration birth and death density matrix in random environment and bi-immigration birth and death process in random environment are introduced.For any bi-immigration birth and death matrix in random environment Q(θ)with birth rateλ〈death rateμ,the following results are proved,(1)there is an unique q-process in random environment,P^-(θ*(0);t)=(p^-(θ^*(0);t,i,j),i,j≥0),which is ergodic,that is,lim t→∞(θ^*(0);t,i,j)=π^-(θ^*(0);j)≥0 does not depend on i≥0 and∑j≥0π(θ*(0);j)=1,(2)there is a bi-immigration birth and death process in random enjvironment(X^*={X^*,t≥0},ε^*={εt,t∈(-∞,∞)})with random transition matrix P^-(θ^*(0);t)such that X^*is a strictly stationary process.展开更多
This article is a continuation of[9].Based on the discussion of random Kolmogorov forward（backward）equations,for any given q-matrix in random environment, Q（θ）=（q（θ;x,y）,x,y∈X）,an infinite class of q-proces...This article is a continuation of[9].Based on the discussion of random Kolmogorov forward（backward）equations,for any given q-matrix in random environment, Q（θ）=（q（θ;x,y）,x,y∈X）,an infinite class of q-processes in random environments satisfying the random Kolmogorov forward（backward）equation is constructed.Moreover, under some conditions,all the q-processes in random environments satisfying the random Kolmogorov forward（backward）equation are constructed.展开更多
Green manufacturing is a mode to realize environmental friendliness by considering the environmental impact and energy consumption in manufacturing process.In order to make an environmental friendly assessment for man...Green manufacturing is a mode to realize environmental friendliness by considering the environmental impact and energy consumption in manufacturing process.In order to make an environmental friendly assessment for manufacturing process,a multi-criteria decision making( MCDM) model combined with fuzzy analytic hierarchy process( FAHP) and fuzzy technique for order preference by similarity to ideal solution( FTOPSIS) is proposed in this work.The environmental and resource criteria and manufacturing process objects are identified as the first step.Then,the weights of the criteria are calculated by FAHP.Finally,based on experts' evaluation using fuzzy words,the manufacturing process objects are ranked by FTOPSIS.The proposed methodology is applied to a gear shaft manufacturing.The sensitivity analysis and comparisons are implemented to prove its robustness and effectiveness for the ecofriendly assessment for process objects.展开更多
Located in Western Hubei Province,this deposit is a large-scale Ag-V ore deposit,listed among the fifth type of silver deposit in China.1 Geological Characteristics It lies in the NE sector of the Yangtze flat of the ...Located in Western Hubei Province,this deposit is a large-scale Ag-V ore deposit,listed among the fifth type of silver deposit in China.1 Geological Characteristics It lies in the NE sector of the Yangtze flat of the Yangtze paraplatform.There are sporadically magmatic rocks and fold basement made up of upper Archaeozoicmiddle and lower Proterozoic strata.The sedimentary cover consists of Sinian-lower Paleozoic marine sediments,Mesozoic-Cenozoic intercalated marine and nonmarine sediments or nonmarine sediments.展开更多
As computer simulation increasingly supports engine er ing design and manufacture, the requirement for a computer software environment providing an integration platform for computational engineering software increas e...As computer simulation increasingly supports engine er ing design and manufacture, the requirement for a computer software environment providing an integration platform for computational engineering software increas es. A key component of an integrated environment is the use of computational eng ineering to assist and support solutions for complex design. Computer methods fo r structural, flow and thermal analysis are well developed and have been used in design for many years. Many software packages are now available which provi de an advanced capability. However, they are not designed for modelling of powde r forming processes. This paper describes the powder compaction software (PCS_SU T), which is designed for pre- and post-processing for computational simulatio n of the process compaction of powder. In the PCS_SUT software, the adaptive analysis of transient metal powder forming process is simulated by the finite element method based on deformation theories . The error estimates and adaptive remeshing schemes are applied for updated co -ordinate analysis. A generalized Newmark scheme is used for the time domain di scretization and the final nonlinear equations are solved by a Newton-Raphson p rocedure. An incremental elasto-plastic material model is used to simulate the compaction process. To describe the constitutive model of nonlinear behaviour of powder materials, a combination of Mohr-Coulomb and elliptical yield cap model is applied. This model reflects the yielding, frictional and densification char acteristics of powder along with strain and geometrical hardening which occurs d uring the compaction process. A hardening rule is used to define the dependence of the yield surface on the degree of plastic straining. A plasticity theory for friction is employed in the treatment of the powder-tooling interface. The inv olvement of two different materials, which have contact and relative movement in relation to each other, must be considered. A special formulation for friction modelling is coupled with a material formulation. The interface behaviour betwee n the die and the powder is modelled by using an interface element mesh. In the present paper, we have demonstrated pre- and post-processor finite elem ent software, written in Visual Basic, to generate the graphical model and visua lly display the computed results. The software consist of three main part: · Pre-processor: It is used to create the model, generate an app ropriate finite element grid, apply the appropriate boundary conditions, and vie w the total model. The geometric model can be used to associate the mesh with th e physical attributes such as element properties, material properties, or loads and boundary conditions. · Analysis: It can deal with two-dimensional and axi-symmetric applications for linear and non-linear behaviour of material in static and dyna mic analyses. Both triangular and quadrilateral elements are available in the e lement library, including 3-noded, 6-noded and 7-noded (T6B1) triangles and 4 -noded, 8-noded and 9-noded quadrilaterals. The direct implicit algorithm bas ed on the generalized Newmark scheme is used for the time integration and an aut omatic time step control facility is provided. For non-linear iteration, choice s among fully or modified Newton-Raphson method and quasi-Newton method, using the initial stiffness method, Davidon inverse method or BFGS inverse method, ar e possible. · Post-processor: It provides visualization of the computed resu lts, when the finite element model and analysis have been completed. Post-proce ssing is vital to allow the appropriate interpretation of the completed results of the finite element analysis. It provides the visual means to interpret the va st amounts of computed results generated. Finally, the powder behaviour during the compaction of a multi-level component is numerically simulated by the PCS_SUT software, as shown in Fig.1. The predict ive compaction forces at different displacements are computed and compared with the available experimental展开更多
In this paper,the development process of the construction of soil environmental quality standards in China is reviewed,and the construction situation of soil environmental quality standards in typical developed countr...In this paper,the development process of the construction of soil environmental quality standards in China is reviewed,and the construction situation of soil environmental quality standards in typical developed countries is introduced.According to characteristics of soil environment and practice of soil environment management in China,the relevant suggestions are discussed,thereby further perfecting construction work of soil environmental quality standards in China.展开更多
Soil environmental capacity is defined as the maximumpermitted load of the pollutant in a cettain soil environmental unitwithin a certain temporal period. With that load, the criteria canbe maintained, production and ...Soil environmental capacity is defined as the maximumpermitted load of the pollutant in a cettain soil environmental unitwithin a certain temporal period. With that load, the criteria canbe maintained, production and quality of crops can be gqaranteed.Regional soil capacity is the function of physical geographiccharacteristics. In determining capacity of sierozem, key stepsinclude: (1) establishing the criteria on comprehensive basis, (2)calculating the permitted input with the application of the capacitymodel. Dynamic capacity of Cd, Cu, As and Pb for sierozem isreported and compared with that of phaiozem and red 1oam.According to the results, it is obvious that regional differentiationin capacity is distinct and the distribution pattern of permittedload is closely related to the spacial variation of physicalgeographic processes.展开更多
文摘In this paper, we investigate Galton-Watson branching processes in random environments. In the case where the environmental process is a Markov chain which is positive recurrent or has a transition matrix Q (θ,α) such that sup_θ Q (θ,α)> 0 for some α, we prove that the model has the asymptotic behavior being similar to that of Galton-Watson branching processes. In other case where the environments are non-stationary independent, the sufficient conditions are obtained for certain extinction and uncertain extinction for the model.
文摘The concepts of Markov process in random environment, q-matrix in random environment, and q-process in random environment are introduced. The minimal q-process in random environment is constructed and the necessary and sufficient conditions for the uniqueness of q-process in random environment are given.
基金Supported by the National Natural Science Foundation of China (10871200)
文摘In this article, we obtain the central limit theorem and the law of the iterated logarithm for Galton-Watson processes in i.i.d, random environments.
基金Supported by the NNSF of China(10371092,10771185)the Foundation of Whuan University
文摘The concepts of bi-immigration birth and death density matrix in random environment and bi-immigration birth and death process in random environment are introduced.For any bi-immigration birth and death matrix in random environment Q(θ)with birth rateλ〈death rateμ,the following results are proved,(1)there is an unique q-process in random environment,P^-(θ*(0);t)=(p^-(θ^*(0);t,i,j),i,j≥0),which is ergodic,that is,lim t→∞(θ^*(0);t,i,j)=π^-(θ^*(0);j)≥0 does not depend on i≥0 and∑j≥0π(θ*(0);j)=1,(2)there is a bi-immigration birth and death process in random enjvironment(X^*={X^*,t≥0},ε^*={εt,t∈(-∞,∞)})with random transition matrix P^-(θ^*(0);t)such that X^*is a strictly stationary process.
基金the NNSF of China(10371092,10771185,10471148)the Foundation of Wuhan University
文摘This article is a continuation of[9].Based on the discussion of random Kolmogorov forward（backward）equations,for any given q-matrix in random environment, Q（θ）=（q（θ;x,y）,x,y∈X）,an infinite class of q-processes in random environments satisfying the random Kolmogorov forward（backward）equation is constructed.Moreover, under some conditions,all the q-processes in random environments satisfying the random Kolmogorov forward（backward）equation are constructed.
基金National Natural Science Foundation of China(No.51475459)the Priority Academic Program Development of Jiangsu Higher Education Institutions of China(No.PAPD)
文摘Green manufacturing is a mode to realize environmental friendliness by considering the environmental impact and energy consumption in manufacturing process.In order to make an environmental friendly assessment for manufacturing process,a multi-criteria decision making( MCDM) model combined with fuzzy analytic hierarchy process( FAHP) and fuzzy technique for order preference by similarity to ideal solution( FTOPSIS) is proposed in this work.The environmental and resource criteria and manufacturing process objects are identified as the first step.Then,the weights of the criteria are calculated by FAHP.Finally,based on experts' evaluation using fuzzy words,the manufacturing process objects are ranked by FTOPSIS.The proposed methodology is applied to a gear shaft manufacturing.The sensitivity analysis and comparisons are implemented to prove its robustness and effectiveness for the ecofriendly assessment for process objects.
文摘Located in Western Hubei Province,this deposit is a large-scale Ag-V ore deposit,listed among the fifth type of silver deposit in China.1 Geological Characteristics It lies in the NE sector of the Yangtze flat of the Yangtze paraplatform.There are sporadically magmatic rocks and fold basement made up of upper Archaeozoicmiddle and lower Proterozoic strata.The sedimentary cover consists of Sinian-lower Paleozoic marine sediments,Mesozoic-Cenozoic intercalated marine and nonmarine sediments or nonmarine sediments.
文摘As computer simulation increasingly supports engine er ing design and manufacture, the requirement for a computer software environment providing an integration platform for computational engineering software increas es. A key component of an integrated environment is the use of computational eng ineering to assist and support solutions for complex design. Computer methods fo r structural, flow and thermal analysis are well developed and have been used in design for many years. Many software packages are now available which provi de an advanced capability. However, they are not designed for modelling of powde r forming processes. This paper describes the powder compaction software (PCS_SU T), which is designed for pre- and post-processing for computational simulatio n of the process compaction of powder. In the PCS_SUT software, the adaptive analysis of transient metal powder forming process is simulated by the finite element method based on deformation theories . The error estimates and adaptive remeshing schemes are applied for updated co -ordinate analysis. A generalized Newmark scheme is used for the time domain di scretization and the final nonlinear equations are solved by a Newton-Raphson p rocedure. An incremental elasto-plastic material model is used to simulate the compaction process. To describe the constitutive model of nonlinear behaviour of powder materials, a combination of Mohr-Coulomb and elliptical yield cap model is applied. This model reflects the yielding, frictional and densification char acteristics of powder along with strain and geometrical hardening which occurs d uring the compaction process. A hardening rule is used to define the dependence of the yield surface on the degree of plastic straining. A plasticity theory for friction is employed in the treatment of the powder-tooling interface. The inv olvement of two different materials, which have contact and relative movement in relation to each other, must be considered. A special formulation for friction modelling is coupled with a material formulation. The interface behaviour betwee n the die and the powder is modelled by using an interface element mesh. In the present paper, we have demonstrated pre- and post-processor finite elem ent software, written in Visual Basic, to generate the graphical model and visua lly display the computed results. The software consist of three main part: · Pre-processor: It is used to create the model, generate an app ropriate finite element grid, apply the appropriate boundary conditions, and vie w the total model. The geometric model can be used to associate the mesh with th e physical attributes such as element properties, material properties, or loads and boundary conditions. · Analysis: It can deal with two-dimensional and axi-symmetric applications for linear and non-linear behaviour of material in static and dyna mic analyses. Both triangular and quadrilateral elements are available in the e lement library, including 3-noded, 6-noded and 7-noded (T6B1) triangles and 4 -noded, 8-noded and 9-noded quadrilaterals. The direct implicit algorithm bas ed on the generalized Newmark scheme is used for the time integration and an aut omatic time step control facility is provided. For non-linear iteration, choice s among fully or modified Newton-Raphson method and quasi-Newton method, using the initial stiffness method, Davidon inverse method or BFGS inverse method, ar e possible. · Post-processor: It provides visualization of the computed resu lts, when the finite element model and analysis have been completed. Post-proce ssing is vital to allow the appropriate interpretation of the completed results of the finite element analysis. It provides the visual means to interpret the va st amounts of computed results generated. Finally, the powder behaviour during the compaction of a multi-level component is numerically simulated by the PCS_SUT software, as shown in Fig.1. The predict ive compaction forces at different displacements are computed and compared with the available experimental
基金Supported by Preparation Project of Science Popularization Materials for Publicity and Education of Soil Environmental Protection,Ministry of Environmental Protection(H201606)
文摘In this paper,the development process of the construction of soil environmental quality standards in China is reviewed,and the construction situation of soil environmental quality standards in typical developed countries is introduced.According to characteristics of soil environment and practice of soil environment management in China,the relevant suggestions are discussed,thereby further perfecting construction work of soil environmental quality standards in China.
文摘Soil environmental capacity is defined as the maximumpermitted load of the pollutant in a cettain soil environmental unitwithin a certain temporal period. With that load, the criteria canbe maintained, production and quality of crops can be gqaranteed.Regional soil capacity is the function of physical geographiccharacteristics. In determining capacity of sierozem, key stepsinclude: (1) establishing the criteria on comprehensive basis, (2)calculating the permitted input with the application of the capacitymodel. Dynamic capacity of Cd, Cu, As and Pb for sierozem isreported and compared with that of phaiozem and red 1oam.According to the results, it is obvious that regional differentiationin capacity is distinct and the distribution pattern of permittedload is closely related to the spacial variation of physicalgeographic processes.
