Consider the reducibility of a class of nonlinear quasi-periodic systems with multiple eigenvalues under perturbational hypothesis in the neighborhood of equilibrium. That is, consider the following system x = (A + ...Consider the reducibility of a class of nonlinear quasi-periodic systems with multiple eigenvalues under perturbational hypothesis in the neighborhood of equilibrium. That is, consider the following system x = (A + εQ( t) )x + eg(t) + h(x, t), where A is a constant matrix with multiple eigenvalues; h = O(x2) (x-4)) ; and h(x, t), Q(t), and g(t) are analytic quasi-periodic with respect to t with the same frequencies. Under suitable hypotheses of non-resonance conditions and non-degeneracy conditions, for most sufficiently small ε, the system can be reducible to a nonlinear quasi-periodic system with an equilibrium point by means of a quasi-periodic transformation.展开更多
Barium modified Co/Al2O3 catalysts were prepared by incipient wetness impregnation.The catalysts were characterized by XRD,TPD and DRIFTS.The catalytic activity for Fischer-Tropsch synthesis was measured in a continuo...Barium modified Co/Al2O3 catalysts were prepared by incipient wetness impregnation.The catalysts were characterized by XRD,TPD and DRIFTS.The catalytic activity for Fischer-Tropsch synthesis was measured in a continuously stirred tank reactor.It was found that small amounts of BaO(≤2 wt%) improved the cobalt reducibility,which led to more cobalt active sites on the catalyst surface,and then resulted in higher CO conversion and C5+ selectivity.However,for the catalysts with high BaO loadings negative effects on the catalytic activity and selectivity for high hydrocarbons were observed because of low cobalt reducibility.展开更多
The reducibility of iron-bearing burdens was emphasized for improving the operation efficiency of blast furnace. The blast furnace operation of charging the burdens with high reducibility has been numerically evaluate...The reducibility of iron-bearing burdens was emphasized for improving the operation efficiency of blast furnace. The blast furnace operation of charging the burdens with high reducibility has been numerically evaluated using a multi-fluid blast furnace model. The effects of reaction rate constants and diffusion coefficients were investigated separately or simultaneously for clarifying the variations of furnace state. According to the model simulation results, in the upper zone, the indirect reduction of the burdens proceeds at a faster rate and the shaft efficiency is enhanced with the improvement under the conditions of interface reaction and intra-particle diffusion. In the lower zone, direct reduction in molten slag is restrained. As a consequence, CO utilization of top gas is enhanced and the ratio of direct reduction is decreased. It is possible to achieve higher energy efficiency of the blast furnace, and this is represented by the improvement in productivity and the decrease in consumption of reducing agent. The use of high-reducibility burdens contributes to a better performance of blast furnace. More efforts are necessary to develop and apply highreducibility sinter and carbon composite agglomerates for practical application at a blast furnace.展开更多
The effect of Au on the reducibility of La Ce Mn catalyst was studied in the synthetic exhaust gas mixture containing 10% oxygen. The characteristics of samples were analyzed by BET, SEM, XRD and activity evaluation...The effect of Au on the reducibility of La Ce Mn catalyst was studied in the synthetic exhaust gas mixture containing 10% oxygen. The characteristics of samples were analyzed by BET, SEM, XRD and activity evaluation. The results show that, in lean combustion, the performance of perovskite type catalysts is evidently enhanced through adding Au, and specially a satisfying reducibility for NO x is demonstrated between 300~500 ℃. The catalytic activity of samples increases with the loading amount of Au, and the maximum conversion rate for NO x decomposition reaches up to 47% in 360~400 ℃. Moreover, the dispersivity and uniformity of the surface distribution of perovskite with Au have an important influence on the catalytic activity.展开更多
In the Permian–Triassic geological history,the Tibet Tethys domain deposited continuous marine carbonate strata and recorded information related to the largest bioextinct events in the life history of the earth(JiCha...In the Permian–Triassic geological history,the Tibet Tethys domain deposited continuous marine carbonate strata and recorded information related to the largest bioextinct events in the life history of the earth(JiChangjun,2018).The complete Permian–Triassic conodont sequence has been established in the northern margin of the Coqin Basin(Zhou Liqian,2012),which provides a time scale for the study of the paleoceanographic environment evolution in the Tibet Tethys field at the turn of the P/T.This work selected the total organic carbon and sulfur content of the rocks,carbon and oxygen isotopes of carbonate rocks,and the organic carbon isotope index system to study the evolution of the paleo marine environment in this period.展开更多
In this paper, the Dirichlet boundary value problems of the nonlinear beam equation utt + △^2u + αu + εφ(t)(u + u^3) = 0 , α 〉 0 in the dimension one is considered, where u(t,x) and φ(t...In this paper, the Dirichlet boundary value problems of the nonlinear beam equation utt + △^2u + αu + εφ(t)(u + u^3) = 0 , α 〉 0 in the dimension one is considered, where u(t,x) and φ(t) are analytic quasi-periodic functions in t, and e is a small positive real-number parameter. It is proved that the above equation admits a small-amplitude quasi-periodic solution. The proof is based on an infinite dimensional KAM iteration procedure.展开更多
In this paper, we use KAM methods to prove that there are positive measure Cantor sets such that for small perturbation parameters in these Cantor sets a class of almost periodic linear differential equations are redu...In this paper, we use KAM methods to prove that there are positive measure Cantor sets such that for small perturbation parameters in these Cantor sets a class of almost periodic linear differential equations are reducible.展开更多
The reduction process of Eu2O3 on TiO2 and other supports is investigated in detail by Mossbauer spectroscopy. The reducibility of Eu2O3 is greatly enhanced when it is supported on a surface of support. This is due to...The reduction process of Eu2O3 on TiO2 and other supports is investigated in detail by Mossbauer spectroscopy. The reducibility of Eu2O3 is greatly enhanced when it is supported on a surface of support. This is due to the solid-solid interaction between the oxide and the support.展开更多
We consider a central hyperplane arrangement in a three-dimensional vector space. The definition of characteristic form to a hyperplane arrangement is given and we could make use of characteristic form to judge the re...We consider a central hyperplane arrangement in a three-dimensional vector space. The definition of characteristic form to a hyperplane arrangement is given and we could make use of characteristic form to judge the reducibility of this arrangement. In addition, the relationship between the reducibility and freeness of a hyperplane arrangement is given展开更多
In this work, a new model reduction technique is introduced. The proposed technique is derived using the matrix reducibility concept. The eigenvalues of the reduced model are preserved; that is, the reduced model eige...In this work, a new model reduction technique is introduced. The proposed technique is derived using the matrix reducibility concept. The eigenvalues of the reduced model are preserved; that is, the reduced model eigenvalues are a subset of the full order model eigenvalues. This preservation of the eigenvalues makes the mathematical model closer to the physical model. Finally, the outcomes of this method are fully illustrated using simulations of two numeric examples.展开更多
In 1986, G.X. Viennot introduced the theory of heaps of pieces as a visualization of Cartier and Foata’s “partially commutative monoids”. These are essentially labeled posets satisfying a few additional properties,...In 1986, G.X. Viennot introduced the theory of heaps of pieces as a visualization of Cartier and Foata’s “partially commutative monoids”. These are essentially labeled posets satisfying a few additional properties, and one natural setting where they arise is as models of reduced words in Coxeter groups. In this paper, we introduce a cyclic version of a heap, which loosely speaking, can be thought of as taking a heap and wrapping it into a cylinder. We call this object a toric heap, because we formalize it as a labeled toric poset, which is a cyclic version of an ordinary poset. Defining the category of toric heaps leads to the notion of certain morphisms such as toric extensions. We study toric heaps in Coxeter theory, because a cyclic shift of a reduced word is simply a conjugate by an initial or terminal generator. As such, we formalize and study a framework that we call cyclic reducibility in Coxeter theory, which is closely related to conjugacy. We introduce what it means for elements to be torically reduced, which is a stronger condition than simply being cyclically reduced. Along the way, we encounter a new class of elements that we call torically fully commutative (TFC), which are those that have a unique cyclic commutativity class, and comprise a strictly bigger class than the cyclically fully commutative (CFC) elements. We prove several cyclic analogues of results on fully commutative (FC) elements due to Stembridge. We conclude with how this framework fits into recent work in Coxeter groups, and we correct a minor flaw in a few recently published theorems.展开更多
In this work, the reducibility of quasi-periodic systems with strong parametric excitation is studied. We first applied a special case of Lyapunov-Perron (L-P) transformation for time periodic system known as the Lyap...In this work, the reducibility of quasi-periodic systems with strong parametric excitation is studied. We first applied a special case of Lyapunov-Perron (L-P) transformation for time periodic system known as the Lyapunov-Floquet (L-F) transformation to generate a dynamically equivalent system. Then, we used the quasi-periodicnear-identity transformation to reduce this dynamically equivalent system to a constant coefficient system by solving homological equations via harmonic balance. In this process, we obtained the reducibility/resonance conditions that needed to be satisfied to convert a quasi-periodic system in to a constant one. Assuming the reducibility is possible, we obtain the L-P transformation that can transform original quasi-periodic system into a system with constant coefficients. Two examples are presented that show the application of this approach.展开更多
This paper focuses on the reducibility of two-dimensional almost periodic system with small perturbation. We use the KAM iterative method to get the reducibility by an almost periodic transformation. The system has be...This paper focuses on the reducibility of two-dimensional almost periodic system with small perturbation. We use the KAM iterative method to get the reducibility by an almost periodic transformation. The system has been reduced to a simple form. So we have dealt with the small perturbation problem of the almost periodic system.展开更多
The reduction process of Eu2O3 on TiO2 and other supports is investigated in detail by Mossbauer spectroscopy. The reducibility of Eu2O3 is greatly enhanced when it is supported on a surface of support. This is due to...The reduction process of Eu2O3 on TiO2 and other supports is investigated in detail by Mossbauer spectroscopy. The reducibility of Eu2O3 is greatly enhanced when it is supported on a surface of support. This is due to the solid-solid interaction between the oxide and the support.展开更多
We prove the reducibility of analytic multipliers M_(φ)with a class of finite Blaschke products symbolφon the Sobolev disk algebra R(D).We also describe their nontrivial minimal reducing subspaces.
Polarization and conductance losses are the fundamental dielectric attenuation mechanisms for graphene-based absorbers, but it is not fully understood in revealing the loss mechanism of affect graphene itself. For the...Polarization and conductance losses are the fundamental dielectric attenuation mechanisms for graphene-based absorbers, but it is not fully understood in revealing the loss mechanism of affect graphene itself. For the first time, the reduced graphene oxide(RGO) based absorbers are developed with regulatory absorption properties and the absorption mechanism of RGO is mainly originated from the carrier injection behavior of trace metal Fe nanosheets on graphene. Accordingly, the minimum reflection loss(RLmin) of Fe/RGO-2composite reaches-53.38 dB(2.45 mm), and the effective absorption bandwidth achieves 7.52 GHz(2.62 mm) with lower filling loading of 2 wt%. Using off-axis electron hologram testing combined with simulation calculation and carrier transport property experiments, we demonstrate here the carrier injection behavior from Fe to graphene at the interface and the induced charge accumulation and rearrangement, resulting in the increased interfacial and dipole polarization and the conductance loss. This work has confirmed that regulating the dielectric property of graphene itself by adding trace metals can not only ensure good impedance matching, but also fully exploit the dielectric loss ability of graphene at low filler content,which opens up an efficient way for designing lightweight absorbers and may be extended to other types materials.展开更多
For an operator weighted shift S,the essential spectrum σ_e(S) and the indices associated with holes in σ_e(S) are described.Moreover,Banach reducibility of S is investigated and a condition for S~* to be a Cowen-Do...For an operator weighted shift S,the essential spectrum σ_e(S) and the indices associated with holes in σ_e(S) are described.Moreover,Banach reducibility of S is investigated and a condition for S~* to be a Cowen-Douglas operator is characterized.展开更多
In this paper, by the KAM method, under weaker small denominator conditions and nondegeneracy conditions, we prove a positive measure reducibility for quasi-periodic linear systems close to constant: X = (A(λ) ...In this paper, by the KAM method, under weaker small denominator conditions and nondegeneracy conditions, we prove a positive measure reducibility for quasi-periodic linear systems close to constant: X = (A(λ) + F(ψ, λ))X, ψ=ωwhere the parameter λ∈ (a, b), w is a fixed Diophantine vector, which is a generalization of jorba & Simo's positive measure reducibility result.展开更多
文摘Consider the reducibility of a class of nonlinear quasi-periodic systems with multiple eigenvalues under perturbational hypothesis in the neighborhood of equilibrium. That is, consider the following system x = (A + εQ( t) )x + eg(t) + h(x, t), where A is a constant matrix with multiple eigenvalues; h = O(x2) (x-4)) ; and h(x, t), Q(t), and g(t) are analytic quasi-periodic with respect to t with the same frequencies. Under suitable hypotheses of non-resonance conditions and non-degeneracy conditions, for most sufficiently small ε, the system can be reducible to a nonlinear quasi-periodic system with an equilibrium point by means of a quasi-periodic transformation.
基金supported by the National Natural Science Foundation of China(Grants No:20590360 and 20773166)
文摘Barium modified Co/Al2O3 catalysts were prepared by incipient wetness impregnation.The catalysts were characterized by XRD,TPD and DRIFTS.The catalytic activity for Fischer-Tropsch synthesis was measured in a continuously stirred tank reactor.It was found that small amounts of BaO(≤2 wt%) improved the cobalt reducibility,which led to more cobalt active sites on the catalyst surface,and then resulted in higher CO conversion and C5+ selectivity.However,for the catalysts with high BaO loadings negative effects on the catalytic activity and selectivity for high hydrocarbons were observed because of low cobalt reducibility.
文摘The reducibility of iron-bearing burdens was emphasized for improving the operation efficiency of blast furnace. The blast furnace operation of charging the burdens with high reducibility has been numerically evaluated using a multi-fluid blast furnace model. The effects of reaction rate constants and diffusion coefficients were investigated separately or simultaneously for clarifying the variations of furnace state. According to the model simulation results, in the upper zone, the indirect reduction of the burdens proceeds at a faster rate and the shaft efficiency is enhanced with the improvement under the conditions of interface reaction and intra-particle diffusion. In the lower zone, direct reduction in molten slag is restrained. As a consequence, CO utilization of top gas is enhanced and the ratio of direct reduction is decreased. It is possible to achieve higher energy efficiency of the blast furnace, and this is represented by the improvement in productivity and the decrease in consumption of reducing agent. The use of high-reducibility burdens contributes to a better performance of blast furnace. More efforts are necessary to develop and apply highreducibility sinter and carbon composite agglomerates for practical application at a blast furnace.
文摘The effect of Au on the reducibility of La Ce Mn catalyst was studied in the synthetic exhaust gas mixture containing 10% oxygen. The characteristics of samples were analyzed by BET, SEM, XRD and activity evaluation. The results show that, in lean combustion, the performance of perovskite type catalysts is evidently enhanced through adding Au, and specially a satisfying reducibility for NO x is demonstrated between 300~500 ℃. The catalytic activity of samples increases with the loading amount of Au, and the maximum conversion rate for NO x decomposition reaches up to 47% in 360~400 ℃. Moreover, the dispersivity and uniformity of the surface distribution of perovskite with Au have an important influence on the catalytic activity.
基金supported by the National Natural Science Foundation of China(grant No.41602122)the National Technological Projects(grant No.2016ZX05034-001-003)the China Geological Survey(grant No.DD20160161)
文摘In the Permian–Triassic geological history,the Tibet Tethys domain deposited continuous marine carbonate strata and recorded information related to the largest bioextinct events in the life history of the earth(JiChangjun,2018).The complete Permian–Triassic conodont sequence has been established in the northern margin of the Coqin Basin(Zhou Liqian,2012),which provides a time scale for the study of the paleoceanographic environment evolution in the Tibet Tethys field at the turn of the P/T.This work selected the total organic carbon and sulfur content of the rocks,carbon and oxygen isotopes of carbonate rocks,and the organic carbon isotope index system to study the evolution of the paleo marine environment in this period.
基金The Science Research Plan(Jijiaokehezi[2016]166)of Jilin Province Education Department During the 13th Five-Year Periodthe Science Research Starting Foundation(2015023)of Jilin Agricultural University
文摘In this paper, the Dirichlet boundary value problems of the nonlinear beam equation utt + △^2u + αu + εφ(t)(u + u^3) = 0 , α 〉 0 in the dimension one is considered, where u(t,x) and φ(t) are analytic quasi-periodic functions in t, and e is a small positive real-number parameter. It is proved that the above equation admits a small-amplitude quasi-periodic solution. The proof is based on an infinite dimensional KAM iteration procedure.
基金The NSF(11571327) of ChinaNSF(ZR2013AM026) of Shandong Province
文摘In this paper, we use KAM methods to prove that there are positive measure Cantor sets such that for small perturbation parameters in these Cantor sets a class of almost periodic linear differential equations are reducible.
文摘The reduction process of Eu2O3 on TiO2 and other supports is investigated in detail by Mossbauer spectroscopy. The reducibility of Eu2O3 is greatly enhanced when it is supported on a surface of support. This is due to the solid-solid interaction between the oxide and the support.
文摘We consider a central hyperplane arrangement in a three-dimensional vector space. The definition of characteristic form to a hyperplane arrangement is given and we could make use of characteristic form to judge the reducibility of this arrangement. In addition, the relationship between the reducibility and freeness of a hyperplane arrangement is given
文摘In this work, a new model reduction technique is introduced. The proposed technique is derived using the matrix reducibility concept. The eigenvalues of the reduced model are preserved; that is, the reduced model eigenvalues are a subset of the full order model eigenvalues. This preservation of the eigenvalues makes the mathematical model closer to the physical model. Finally, the outcomes of this method are fully illustrated using simulations of two numeric examples.
文摘In 1986, G.X. Viennot introduced the theory of heaps of pieces as a visualization of Cartier and Foata’s “partially commutative monoids”. These are essentially labeled posets satisfying a few additional properties, and one natural setting where they arise is as models of reduced words in Coxeter groups. In this paper, we introduce a cyclic version of a heap, which loosely speaking, can be thought of as taking a heap and wrapping it into a cylinder. We call this object a toric heap, because we formalize it as a labeled toric poset, which is a cyclic version of an ordinary poset. Defining the category of toric heaps leads to the notion of certain morphisms such as toric extensions. We study toric heaps in Coxeter theory, because a cyclic shift of a reduced word is simply a conjugate by an initial or terminal generator. As such, we formalize and study a framework that we call cyclic reducibility in Coxeter theory, which is closely related to conjugacy. We introduce what it means for elements to be torically reduced, which is a stronger condition than simply being cyclically reduced. Along the way, we encounter a new class of elements that we call torically fully commutative (TFC), which are those that have a unique cyclic commutativity class, and comprise a strictly bigger class than the cyclically fully commutative (CFC) elements. We prove several cyclic analogues of results on fully commutative (FC) elements due to Stembridge. We conclude with how this framework fits into recent work in Coxeter groups, and we correct a minor flaw in a few recently published theorems.
文摘In this work, the reducibility of quasi-periodic systems with strong parametric excitation is studied. We first applied a special case of Lyapunov-Perron (L-P) transformation for time periodic system known as the Lyapunov-Floquet (L-F) transformation to generate a dynamically equivalent system. Then, we used the quasi-periodicnear-identity transformation to reduce this dynamically equivalent system to a constant coefficient system by solving homological equations via harmonic balance. In this process, we obtained the reducibility/resonance conditions that needed to be satisfied to convert a quasi-periodic system in to a constant one. Assuming the reducibility is possible, we obtain the L-P transformation that can transform original quasi-periodic system into a system with constant coefficients. Two examples are presented that show the application of this approach.
文摘This paper focuses on the reducibility of two-dimensional almost periodic system with small perturbation. We use the KAM iterative method to get the reducibility by an almost periodic transformation. The system has been reduced to a simple form. So we have dealt with the small perturbation problem of the almost periodic system.
文摘The reduction process of Eu2O3 on TiO2 and other supports is investigated in detail by Mossbauer spectroscopy. The reducibility of Eu2O3 is greatly enhanced when it is supported on a surface of support. This is due to the solid-solid interaction between the oxide and the support.
文摘We prove the reducibility of analytic multipliers M_(φ)with a class of finite Blaschke products symbolφon the Sobolev disk algebra R(D).We also describe their nontrivial minimal reducing subspaces.
基金supported by National Natural Science Foundation of China (NSFC 52372041, 52302087, 51772060, 51672059 and 51621091)Heilongjiang Touyan Team Program+1 种基金the Fundamental Research Funds for the Central Universities (Grant No. HIT.OCEF.2021003)the Shanghai Aerospace Science and Technology Innovation Fund (SAST2022-60)。
文摘Polarization and conductance losses are the fundamental dielectric attenuation mechanisms for graphene-based absorbers, but it is not fully understood in revealing the loss mechanism of affect graphene itself. For the first time, the reduced graphene oxide(RGO) based absorbers are developed with regulatory absorption properties and the absorption mechanism of RGO is mainly originated from the carrier injection behavior of trace metal Fe nanosheets on graphene. Accordingly, the minimum reflection loss(RLmin) of Fe/RGO-2composite reaches-53.38 dB(2.45 mm), and the effective absorption bandwidth achieves 7.52 GHz(2.62 mm) with lower filling loading of 2 wt%. Using off-axis electron hologram testing combined with simulation calculation and carrier transport property experiments, we demonstrate here the carrier injection behavior from Fe to graphene at the interface and the induced charge accumulation and rearrangement, resulting in the increased interfacial and dipole polarization and the conductance loss. This work has confirmed that regulating the dielectric property of graphene itself by adding trace metals can not only ensure good impedance matching, but also fully exploit the dielectric loss ability of graphene at low filler content,which opens up an efficient way for designing lightweight absorbers and may be extended to other types materials.
基金Supported by MCME.Doctoral Foundation of the Ministry of Education and Science Foundation of Liaoning University
文摘For an operator weighted shift S,the essential spectrum σ_e(S) and the indices associated with holes in σ_e(S) are described.Moreover,Banach reducibility of S is investigated and a condition for S~* to be a Cowen-Douglas operator is characterized.
基金The work is supported by the National Natural Science Foundation of China (19925107) and the Special Funds for Major State Basic Research Projects (973 Projects)
文摘In this paper, by the KAM method, under weaker small denominator conditions and nondegeneracy conditions, we prove a positive measure reducibility for quasi-periodic linear systems close to constant: X = (A(λ) + F(ψ, λ))X, ψ=ωwhere the parameter λ∈ (a, b), w is a fixed Diophantine vector, which is a generalization of jorba & Simo's positive measure reducibility result.