Pure WC-6%Co nanosized composite powders were synthesized via a low-temperature method.The effects of carbon source on microstructure characteristic of composite powders were investigated,and the effects of heat-treat...Pure WC-6%Co nanosized composite powders were synthesized via a low-temperature method.The effects of carbon source on microstructure characteristic of composite powders were investigated,and the effects of heat-treatment parameter on carbon content of composite powders were also discussed.The results of SEM and XRD revealed that the carbon decomposing from glucose was more active than carbon black.Therefore,WC-Co nanosized composite powders could be synthesized at 900°C for 1 h under a hydrogen atmosphere.The individual WC grains were bonded together into a long strip under the action of cobalt.The results of carbon analysis revealed that the total carbon content decreased with the increase of the temperature in the range of 800-1000°C.Moreover,the total carbon content and the compounded carbon increased with the increase of the flow rate of H2 in the range of 1.1-1.9 m3/h.展开更多
We investigate the leading SUSY-QCD contributions to the branch ratio (BR) oft→ch~0 within the context of the minimal supersymmetric standard model (MSSM) with complex parameters,assuming more generally that there is...We investigate the leading SUSY-QCD contributions to the branch ratio (BR) oft→ch~0 within the context of the minimal supersymmetric standard model (MSSM) with complex parameters,assuming more generally that there is a misalignment between the squark and quark that leads to a flavor non-diagonal squark mass matrix.We introduce complex phases only in μ and At,namely φ_μ and φ_(Aq),for simplicity,and study the dependence of the BR of t→ch~0 on these phase parameters.Our calculations show that these CP-violation phases and the flavor mixing parameter λ influence the BR oft→ch~0 considerably,and the effect induced by φ_(At) is much larger than that by φ_μ and φ_(Ac(?)u.For different values of the complex parameters μ and A_t that are set in this paper,the BR of t -+ ch~ is in the range of 10~(-7)～10~(-6),depending mainly on the value of the trilinear coupling A_t.展开更多
The simplified incidence function model which is driven by the colored correlated noises is employed to investigate the extinction time of a metapopulation perturbed by environments. The approximate Fokker-Planck Equa...The simplified incidence function model which is driven by the colored correlated noises is employed to investigate the extinction time of a metapopulation perturbed by environments. The approximate Fokker-Planck Equation and the mean first passage time which denotes the extinction time （Tex） are obtained by virtue of the Novikov theorem and the Fox approach. After introducing a noise intensity ratio and a dimensionless parameter R = D /α （D and a are the multiplicative and additive colored noise intensities respectively）, and then performing numerical computations, the results indicate that： （i） The absolute value of correlation strength A and its correlation time τ3 play opposite roles on the Tex; （ii） For the case of 0 〈λ〈 1,α and its correlation time τ2 play opposite roles on the Tex in which R〉 1 is the best condition, and there is one-peak structure on the Tex - D plot; （iii） For the case of-1 〈 λ≤ 0, D and its correlation time τ1 play opposite roles on the Tex in which R 〈 1 is the best condition and there is one-peak structure on the Tex - τ2 plot.展开更多
In this review paper,the challenges and some recent developments of adhesive bonding technology in composite aircraft structures are discussed.The durability of bonded joints is defined and presented for parameters th...In this review paper,the challenges and some recent developments of adhesive bonding technology in composite aircraft structures are discussed.The durability of bonded joints is defined and presented for parameters that may influence bonding quality.Presented is also,a numerical design approach for composite joining profiles used to realize adhesive bonding.It is shown that environmental ageing and pre-bond contamination of bonding surfaces may degrade significantly fracture toughness of bonded joints.Moreover,it is obvious that additional research is needed in order to design joining profiles that will enable load transfer through shearing of the bondline.These findings,together with the limited capabilities of existing non-destructive testing techniques,can partially explain the confined use of adhesive bonding in primary composite aircraft structural parts.展开更多
基金Project(51274107)supported by the National Natural Science Foundation of ChinaProject(2015FB127)supported by the Yunnan Natural Science Foundation,ChinaProject(2016P20151130003)supported by Analysis Foundation of Kunming University of Science and Technology,China
文摘Pure WC-6%Co nanosized composite powders were synthesized via a low-temperature method.The effects of carbon source on microstructure characteristic of composite powders were investigated,and the effects of heat-treatment parameter on carbon content of composite powders were also discussed.The results of SEM and XRD revealed that the carbon decomposing from glucose was more active than carbon black.Therefore,WC-Co nanosized composite powders could be synthesized at 900°C for 1 h under a hydrogen atmosphere.The individual WC grains were bonded together into a long strip under the action of cobalt.The results of carbon analysis revealed that the total carbon content decreased with the increase of the temperature in the range of 800-1000°C.Moreover,the total carbon content and the compounded carbon increased with the increase of the flow rate of H2 in the range of 1.1-1.9 m3/h.
基金The project supported in part by National Natura Science Foundation of China and a grant from the University of Science and Technology of China
文摘We investigate the leading SUSY-QCD contributions to the branch ratio (BR) oft→ch~0 within the context of the minimal supersymmetric standard model (MSSM) with complex parameters,assuming more generally that there is a misalignment between the squark and quark that leads to a flavor non-diagonal squark mass matrix.We introduce complex phases only in μ and At,namely φ_μ and φ_(Aq),for simplicity,and study the dependence of the BR of t→ch~0 on these phase parameters.Our calculations show that these CP-violation phases and the flavor mixing parameter λ influence the BR oft→ch~0 considerably,and the effect induced by φ_(At) is much larger than that by φ_μ and φ_(Ac(?)u.For different values of the complex parameters μ and A_t that are set in this paper,the BR of t -+ ch~ is in the range of 10~(-7)～10~(-6),depending mainly on the value of the trilinear coupling A_t.
文摘The simplified incidence function model which is driven by the colored correlated noises is employed to investigate the extinction time of a metapopulation perturbed by environments. The approximate Fokker-Planck Equation and the mean first passage time which denotes the extinction time （Tex） are obtained by virtue of the Novikov theorem and the Fox approach. After introducing a noise intensity ratio and a dimensionless parameter R = D /α （D and a are the multiplicative and additive colored noise intensities respectively）, and then performing numerical computations, the results indicate that： （i） The absolute value of correlation strength A and its correlation time τ3 play opposite roles on the Tex; （ii） For the case of 0 〈λ〈 1,α and its correlation time τ2 play opposite roles on the Tex in which R〉 1 is the best condition, and there is one-peak structure on the Tex - D plot; （iii） For the case of-1 〈 λ≤ 0, D and its correlation time τ1 play opposite roles on the Tex in which R 〈 1 is the best condition and there is one-peak structure on the Tex - τ2 plot.
文摘In this review paper,the challenges and some recent developments of adhesive bonding technology in composite aircraft structures are discussed.The durability of bonded joints is defined and presented for parameters that may influence bonding quality.Presented is also,a numerical design approach for composite joining profiles used to realize adhesive bonding.It is shown that environmental ageing and pre-bond contamination of bonding surfaces may degrade significantly fracture toughness of bonded joints.Moreover,it is obvious that additional research is needed in order to design joining profiles that will enable load transfer through shearing of the bondline.These findings,together with the limited capabilities of existing non-destructive testing techniques,can partially explain the confined use of adhesive bonding in primary composite aircraft structural parts.
