The effect of rare earth on the microstructures, mechanical properties and inclu sions in low sulphur Nb-Ti-bearing steel were investigated. It is shown that t h e transverse yield point, the traverse tensile strength...The effect of rare earth on the microstructures, mechanical properties and inclu sions in low sulphur Nb-Ti-bearing steel were investigated. It is shown that t h e transverse yield point, the traverse tensile strength and elongation of testin g steels decrease initially and then rise with increasing content of rare earth. The impact energy values of the testing steels exhibit a contrary trend. Proper amount of rare earth in the steels can improve the anisotropy of impact toughne ss above -20 ℃ and it does not affect the type of microstructures which ar e st ill composed of ferrites and pearlites, but the pearlite amount increases. On one hand, rare earth cleans the molten steel and reduces the amount of inclusions; on the other hand, rare earth makes the inclusions spheroidizd, refi ned and dispersed, and thus improves the distribution of inclusions.展开更多
In this paper, the existence of the exponential attractors for the Ginzburg- Landau-BBM equations with periodic initial and boundary conditions are obtained by using the squeezing property and the operator dccompositi...In this paper, the existence of the exponential attractors for the Ginzburg- Landau-BBM equations with periodic initial and boundary conditions are obtained by using the squeezing property and the operator dccomposition method.展开更多
In this paper a family, called the pivotal family, of distributions is considered.A pivotal family is determined by a generalized pivotal model. Analytical results show that a great many parametric families of distrib...In this paper a family, called the pivotal family, of distributions is considered.A pivotal family is determined by a generalized pivotal model. Analytical results show that a great many parametric families of distributions are pivotal. In a pivotal family of distributions a general method of deriving fiducial distributions of parameters is proposed. In the method a fiducial model plays an important role. A fiducial model is a function of a random variable with a known distribution, called the pivotal random element, when the observation of a statistic is given.The method of this paper includes some other methods of deriving fiducial distributions. Specially the first fiducial distribution given by Fisher can be derived by the method. For the monotone likelihood ratio family of distributions, which is a pivotal family, the fiducial distributions have a frequentist property in the Neyman-Pearson view. Fiducial distributions of regular parametric functions also have the above frequentist property. Some advantages of the fiducial inference are exhibited in four applications of the fiducial distribution. Many examples are given, in which the fiducial distributions cannot be derived by the existing methods.展开更多
Research status of high strength low alloy TRIP (transformation induced plasticity) steels for automobile structural parts is briefly described. Composition and microstruc-ture factors especially the morphology, size ...Research status of high strength low alloy TRIP (transformation induced plasticity) steels for automobile structural parts is briefly described. Composition and microstruc-ture factors especially the morphology, size and volume fraction of retained austenite, which largely influence the strength and ductility of the steel, are reviewed and discussed one after another. Modelling of the inter-critical annealing and martempering processes as well as the designing of the TRIP steel aided by commercial software are introduced. Some special aspects of the dynamic mechanical properties of TRIP steel are firstly reported.展开更多
CoAl LDHs with different molar ratio of Ni have been prepared by chemical co -precipitation method.XRD results show that these materials have layered struc tures.Electrochemical tests show that Co(Ni)Al LDHs as electr...CoAl LDHs with different molar ratio of Ni have been prepared by chemical co -precipitation method.XRD results show that these materials have layered struc tures.Electrochemical tests show that Co(Ni)Al LDHs as electrode material hav e typical capacit ive properties in a wide voltage range of0.0to0.6V;Co(Ni)Al LDH(Ni∶Co =4∶6)as an electrode material has the highest capacitance of960F · g -1 and good cycling performance.But the poor capacitive properties of NiAl LDH electrode are showed in a narrow voltage range of0.3to0.55V.展开更多
文摘The effect of rare earth on the microstructures, mechanical properties and inclu sions in low sulphur Nb-Ti-bearing steel were investigated. It is shown that t h e transverse yield point, the traverse tensile strength and elongation of testin g steels decrease initially and then rise with increasing content of rare earth. The impact energy values of the testing steels exhibit a contrary trend. Proper amount of rare earth in the steels can improve the anisotropy of impact toughne ss above -20 ℃ and it does not affect the type of microstructures which ar e st ill composed of ferrites and pearlites, but the pearlite amount increases. On one hand, rare earth cleans the molten steel and reduces the amount of inclusions; on the other hand, rare earth makes the inclusions spheroidizd, refi ned and dispersed, and thus improves the distribution of inclusions.
基金Supported by National Natural Science Foundation of China (19801004)
文摘In this paper, the existence of the exponential attractors for the Ginzburg- Landau-BBM equations with periodic initial and boundary conditions are obtained by using the squeezing property and the operator dccomposition method.
基金supported by the National Natural Science Foundation of China(Grant Nos.10271013,10071090).
文摘In this paper a family, called the pivotal family, of distributions is considered.A pivotal family is determined by a generalized pivotal model. Analytical results show that a great many parametric families of distributions are pivotal. In a pivotal family of distributions a general method of deriving fiducial distributions of parameters is proposed. In the method a fiducial model plays an important role. A fiducial model is a function of a random variable with a known distribution, called the pivotal random element, when the observation of a statistic is given.The method of this paper includes some other methods of deriving fiducial distributions. Specially the first fiducial distribution given by Fisher can be derived by the method. For the monotone likelihood ratio family of distributions, which is a pivotal family, the fiducial distributions have a frequentist property in the Neyman-Pearson view. Fiducial distributions of regular parametric functions also have the above frequentist property. Some advantages of the fiducial inference are exhibited in four applications of the fiducial distribution. Many examples are given, in which the fiducial distributions cannot be derived by the existing methods.
基金supported by the National Natural Science Foundation of China(No.50171038)the Chinese Society for Metals and China-Belgium Bilateral Project(No.2001-242).
文摘Research status of high strength low alloy TRIP (transformation induced plasticity) steels for automobile structural parts is briefly described. Composition and microstruc-ture factors especially the morphology, size and volume fraction of retained austenite, which largely influence the strength and ductility of the steel, are reviewed and discussed one after another. Modelling of the inter-critical annealing and martempering processes as well as the designing of the TRIP steel aided by commercial software are introduced. Some special aspects of the dynamic mechanical properties of TRIP steel are firstly reported.
文摘CoAl LDHs with different molar ratio of Ni have been prepared by chemical co -precipitation method.XRD results show that these materials have layered struc tures.Electrochemical tests show that Co(Ni)Al LDHs as electrode material hav e typical capacit ive properties in a wide voltage range of0.0to0.6V;Co(Ni)Al LDH(Ni∶Co =4∶6)as an electrode material has the highest capacitance of960F · g -1 and good cycling performance.But the poor capacitive properties of NiAl LDH electrode are showed in a narrow voltage range of0.3to0.55V.
