In 1994, FAN and RASPAUD posed the following conjecture: every bridgeless cubic graph contains three perfect matchings M 1, M 2 and M 3 such that M 1∩M 2∩M 3=*I.In this paper we obtain the following result: l...In 1994, FAN and RASPAUD posed the following conjecture: every bridgeless cubic graph contains three perfect matchings M 1, M 2 and M 3 such that M 1∩M 2∩M 3=*I.In this paper we obtain the following result: let G be a cyclely-4-edge-connected cubic graph, which has a perfect matching M 1 such that G-M 1 consists of four odd cycles. Then G contains two perfect matchings M 2 and M 3 such that M 1∩M 2∩M 3=*I.展开更多
To make sure that the process of jacket launch occurs in a seml-controlled manner, this paper deals with measurement of kinematic parameters of jacket launch using stereo vision and motion analysis. The system capture...To make sure that the process of jacket launch occurs in a seml-controlled manner, this paper deals with measurement of kinematic parameters of jacket launch using stereo vision and motion analysis. The system captured stereo image sequences by two separate CCD cameras, and then rebuilt 3D coordinates of the feature points to analyze the jacket launch motion. The possibility of combining stereo vision and motion analysis for measurement was examined. Resuhs by experiments using scale model of jacket confirm the theoretical data.展开更多
Solution-phase hydrogen reduction(Sp HR)was introduced into V_(2)O_(3)preparation to overcome disadvantages of traditional reduction roasting,which include a long process,high energy consumption,and generation of poll...Solution-phase hydrogen reduction(Sp HR)was introduced into V_(2)O_(3)preparation to overcome disadvantages of traditional reduction roasting,which include a long process,high energy consumption,and generation of pollution.The research mainly focuses onφ-pH diagrams and kinetics of SpHR.Thermodynamic analysis ofφ-pH diagrams for the V-H_(2)O system demonstrates that V_(2)O_(3)preparation via Sp HR requires a high temperature,a high vanadium concentration,and sufficient hydrogen in acidic solution.Kinetic analyses show that the activation energy of V_(2)O_(3)preparation via SpHR is 38.0679 k J/mol,indicating that the reduction is controlled by a combination of interfacial chemical reaction and internal diffusion.Effects of H;partial pressure(slope K=0.05246)on the reaction rate is not as significant as the vanadium concentration(K=1.58872).V_(2)O_(3)crystals with a purity of 99.59%and a vanadium precipitation rate of 99.83%were obtained under the following conditions:pH=5-6,c(V_(2)O_(3))=0.5 mol/L,p(H;)=4 MPa,m(PdCl;)=10 mg,T=250℃,and t=2.5 h.展开更多
The influence of Al3Zr particles on the hot compression behavior and processing map(PM)of Al-Cu-Li based alloys under isothermal plane-strain compression in the temperature range of 400-500℃and at the strain rates of...The influence of Al3Zr particles on the hot compression behavior and processing map(PM)of Al-Cu-Li based alloys under isothermal plane-strain compression in the temperature range of 400-500℃and at the strain rates of 0.01-10 s^-1 was investigated.The corresponding microstructure was analyzed using optical microscopy(OM),electron back-scattered diffraction(EBSD)and transmission electron microscope(TEM).The results showed that dynamic recovery(DRV)played a greater role than dynamic recrystallization(DRX)in dynamic softening.At low temperatures,the Al3Zr particles were the significant barriers to inhibit DRV and DRX grain growth.When the temperature reached 500℃,the Al3Zr particles readily spread along grain boundaries just like a necklace due to the dissolution of Al3Zr particles and rapid diffusion of Zr through grain boundary,resulting in generating the macroscopic cracks and forming an instability domain at 490-500℃,0.01 s^-1 in the PM.展开更多
In this paper, first, a 3rd-dimensional vertex measurable graphs G is defined, which is an extension of the concept that was introduced in [3]. G = G1 × G2 × G3 is a graph defined over algebra ζ1 ×ζz...In this paper, first, a 3rd-dimensional vertex measurable graphs G is defined, which is an extension of the concept that was introduced in [3]. G = G1 × G2 × G3 is a graph defined over algebra ζ1 ×ζz × ζ3, which consists of all vertex sets that produce sub graphs of G. G1,G2, and G3 are three simple graphs, provided that （G1,ζ1）,（G2,ζz）, and （G3,ζ3） are three vertex measure spaces. Second, in order to maximize the edge＇s set, we present an alternative version of the definition of two-dimension Cartesian product of vertex measurable graphs that was given in [3], with preserving the same properties of the graphs and sub graphs that were illustrated.展开更多
Let G be a k-regular connected graph of order at least six. If G has girth three, its 3-restricted edge connectivity λ3(G) ≤3k-6. The equality holds when G is a cubic or 4-regular connected vertex-transitive graph w...Let G be a k-regular connected graph of order at least six. If G has girth three, its 3-restricted edge connectivity λ3(G) ≤3k-6. The equality holds when G is a cubic or 4-regular connected vertex-transitive graph with the only exception that G is a 4-regular graph with λ3(G) = 4. Furthermore, λ3(G) = 4 if and only if G contains K4 as its subgraph.展开更多
Let G(V,E) be a simple graph and G^k be a k-power graph defined byV(G~*) = V(G), E(G^k) = E(G) ∪{uv|d(u,v) =k} for natural number k. In this paper,it is proved that P_n^3 is a graceful graph.
A proper k-edge coloring f of graph G(V, E) is said to be a k:-adjacent strong edge coloring of graph G(V,E) iff every uv∈E(G) satisfy f[u]≠f/[v], where f[u] = {f(uw)|uw ∈E(G)} then f is called k-adjacent strong ed...A proper k-edge coloring f of graph G(V, E) is said to be a k:-adjacent strong edge coloring of graph G(V,E) iff every uv∈E(G) satisfy f[u]≠f/[v], where f[u] = {f(uw)|uw ∈E(G)} then f is called k-adjacent strong edge coloring of G, is abbreviated k-ASEC: and x'as(G) = min{k|k-ASEC of G} is called the adjacent strong edge chromatic number. In this paper, we study the x'as(G) of Halin graphs with △A(G)≥5.展开更多
文摘In 1994, FAN and RASPAUD posed the following conjecture: every bridgeless cubic graph contains three perfect matchings M 1, M 2 and M 3 such that M 1∩M 2∩M 3=*I.In this paper we obtain the following result: let G be a cyclely-4-edge-connected cubic graph, which has a perfect matching M 1 such that G-M 1 consists of four odd cycles. Then G contains two perfect matchings M 2 and M 3 such that M 1∩M 2∩M 3=*I.
文摘To make sure that the process of jacket launch occurs in a seml-controlled manner, this paper deals with measurement of kinematic parameters of jacket launch using stereo vision and motion analysis. The system captured stereo image sequences by two separate CCD cameras, and then rebuilt 3D coordinates of the feature points to analyze the jacket launch motion. The possibility of combining stereo vision and motion analysis for measurement was examined. Resuhs by experiments using scale model of jacket confirm the theoretical data.
基金financially supported by the National Key R&D Program of China(No.2020YFC1909700)Outstanding Young and Middle-aged Science and Technology Innovation Team Project of Hubei Province,China(No.T201802)the National Natural Science Foundation of China(No.52004187)。
文摘Solution-phase hydrogen reduction(Sp HR)was introduced into V_(2)O_(3)preparation to overcome disadvantages of traditional reduction roasting,which include a long process,high energy consumption,and generation of pollution.The research mainly focuses onφ-pH diagrams and kinetics of SpHR.Thermodynamic analysis ofφ-pH diagrams for the V-H_(2)O system demonstrates that V_(2)O_(3)preparation via Sp HR requires a high temperature,a high vanadium concentration,and sufficient hydrogen in acidic solution.Kinetic analyses show that the activation energy of V_(2)O_(3)preparation via SpHR is 38.0679 k J/mol,indicating that the reduction is controlled by a combination of interfacial chemical reaction and internal diffusion.Effects of H;partial pressure(slope K=0.05246)on the reaction rate is not as significant as the vanadium concentration(K=1.58872).V_(2)O_(3)crystals with a purity of 99.59%and a vanadium precipitation rate of 99.83%were obtained under the following conditions:pH=5-6,c(V_(2)O_(3))=0.5 mol/L,p(H;)=4 MPa,m(PdCl;)=10 mg,T=250℃,and t=2.5 h.
基金Project(11727802)supported by the National Natural Science Foundation of ChinaProjects(2018CDJSK04XK09,106112017CDJQJ328840)supported by the Fundamental Research Funds for the Central Universities,China。
文摘The influence of Al3Zr particles on the hot compression behavior and processing map(PM)of Al-Cu-Li based alloys under isothermal plane-strain compression in the temperature range of 400-500℃and at the strain rates of 0.01-10 s^-1 was investigated.The corresponding microstructure was analyzed using optical microscopy(OM),electron back-scattered diffraction(EBSD)and transmission electron microscope(TEM).The results showed that dynamic recovery(DRV)played a greater role than dynamic recrystallization(DRX)in dynamic softening.At low temperatures,the Al3Zr particles were the significant barriers to inhibit DRV and DRX grain growth.When the temperature reached 500℃,the Al3Zr particles readily spread along grain boundaries just like a necklace due to the dissolution of Al3Zr particles and rapid diffusion of Zr through grain boundary,resulting in generating the macroscopic cracks and forming an instability domain at 490-500℃,0.01 s^-1 in the PM.
文摘In this paper, first, a 3rd-dimensional vertex measurable graphs G is defined, which is an extension of the concept that was introduced in [3]. G = G1 × G2 × G3 is a graph defined over algebra ζ1 ×ζz × ζ3, which consists of all vertex sets that produce sub graphs of G. G1,G2, and G3 are three simple graphs, provided that （G1,ζ1）,（G2,ζz）, and （G3,ζ3） are three vertex measure spaces. Second, in order to maximize the edge＇s set, we present an alternative version of the definition of two-dimension Cartesian product of vertex measurable graphs that was given in [3], with preserving the same properties of the graphs and sub graphs that were illustrated.
文摘Let G be a k-regular connected graph of order at least six. If G has girth three, its 3-restricted edge connectivity λ3(G) ≤3k-6. The equality holds when G is a cubic or 4-regular connected vertex-transitive graph with the only exception that G is a 4-regular graph with λ3(G) = 4. Furthermore, λ3(G) = 4 if and only if G contains K4 as its subgraph.
文摘Let G(V,E) be a simple graph and G^k be a k-power graph defined byV(G~*) = V(G), E(G^k) = E(G) ∪{uv|d(u,v) =k} for natural number k. In this paper,it is proved that P_n^3 is a graceful graph.
基金Supported by NNSFC(19871036)"Qing Lan"talent funds of Lanzhou Railway Institute.
文摘A proper k-edge coloring f of graph G(V, E) is said to be a k:-adjacent strong edge coloring of graph G(V,E) iff every uv∈E(G) satisfy f[u]≠f/[v], where f[u] = {f(uw)|uw ∈E(G)} then f is called k-adjacent strong edge coloring of G, is abbreviated k-ASEC: and x'as(G) = min{k|k-ASEC of G} is called the adjacent strong edge chromatic number. In this paper, we study the x'as(G) of Halin graphs with △A(G)≥5.
