The dissimilar joints of AZ61 and ZK60 magnesium alloys were obtained by tungsten inert gas arc(TIG)welding and activating tungsten inert gas arc(A-TIG)welding processes.Microstructure characterization shows that,the ...The dissimilar joints of AZ61 and ZK60 magnesium alloys were obtained by tungsten inert gas arc(TIG)welding and activating tungsten inert gas arc(A-TIG)welding processes.Microstructure characterization shows that,the fineα-Mg equiaxed dendrite crystals contained Mg17Al12 and MgZn2 particles in the fusion zone.The average size of theα-Mg grains in the fusion zone was refined to 19μm at welding current of 80 A,which resulted in the largest tensile strength of 207 MPa.The tensile strength and the width of the beam of the A-TIG welded AZ61/ZK60 joints showed strong dependence on the amount of TiO2.However,the inhomogeneity of the heat-affected zone near different base metals presented no significant effect on the mechanical properties of the welded joint.展开更多
Complexity measures for keystream multisequences over Z/(N) play a crucial role in designing good stream cipher systems. This correspondence shows a general upper bound on k-error joint N-adic complexity of periodic m...Complexity measures for keystream multisequences over Z/(N) play a crucial role in designing good stream cipher systems. This correspondence shows a general upper bound on k-error joint N-adic complexity of periodic multisequences over Z/(N), and establishes the existence of periodic N-adic multisequences over Z/(N) which simultaneously possess maximal joint N-adic complexity and large k-error joint N-adic complexity. Under some conditions the overwhelming majority of all T-periodic N-adic multisequences over Z/(N) with maximal joint N-adic complexity logN(NT- 1)have a k-error joint N-adic complexity close to logN(NT- 1).展开更多
基金Project(51771160)supported by the National Natural Science Foundation of ChinaProject(2018JJ4048)supported by the Provincial and Municipal Joint Fund for Natural Science of Hunan Province,China
文摘The dissimilar joints of AZ61 and ZK60 magnesium alloys were obtained by tungsten inert gas arc(TIG)welding and activating tungsten inert gas arc(A-TIG)welding processes.Microstructure characterization shows that,the fineα-Mg equiaxed dendrite crystals contained Mg17Al12 and MgZn2 particles in the fusion zone.The average size of theα-Mg grains in the fusion zone was refined to 19μm at welding current of 80 A,which resulted in the largest tensile strength of 207 MPa.The tensile strength and the width of the beam of the A-TIG welded AZ61/ZK60 joints showed strong dependence on the amount of TiO2.However,the inhomogeneity of the heat-affected zone near different base metals presented no significant effect on the mechanical properties of the welded joint.
基金supported by the National Natural Science Foundation of China under Grant Nos.61271271 and 61370089100 Talents Program of Chinese Academy of Sciencethe Fundamental Research Funds for the Central Universities under Grant No.2012HGBZ0622
文摘Complexity measures for keystream multisequences over Z/(N) play a crucial role in designing good stream cipher systems. This correspondence shows a general upper bound on k-error joint N-adic complexity of periodic multisequences over Z/(N), and establishes the existence of periodic N-adic multisequences over Z/(N) which simultaneously possess maximal joint N-adic complexity and large k-error joint N-adic complexity. Under some conditions the overwhelming majority of all T-periodic N-adic multisequences over Z/(N) with maximal joint N-adic complexity logN(NT- 1)have a k-error joint N-adic complexity close to logN(NT- 1).
