Copper matrix composites consisting of chromium （Cr） or ferrochrome （Cr-Fe） as strengthening elements and molybdenum disulfide as a lubricant had been sintered in nitrogen and hydrogen atmosphere, respectively. Th...Copper matrix composites consisting of chromium （Cr） or ferrochrome （Cr-Fe） as strengthening elements and molybdenum disulfide as a lubricant had been sintered in nitrogen and hydrogen atmosphere, respectively. Their morphology and energy-dispersive X-ray spectrometry （EDS） analysis showed that serious interaction occurred between MoS2 and Cr （or Cr-Fe） particles when the samples were sintered in hydrogen atmosphere. Chromium sulfide compound （CrxSy） was formed as a reaction product, which decreased the density and strength of the composites remarkably. This interaction was inhibited when the samples were sintered in nitrogen atmosphere; thus, the mechanical properties of the composites were improved.展开更多
In this paper,we study a class of time-periodic population model with dispersal.It is well known that the existence of the periodic traveling fronts has been established.However,the uniqueness and stability of such fr...In this paper,we study a class of time-periodic population model with dispersal.It is well known that the existence of the periodic traveling fronts has been established.However,the uniqueness and stability of such fronts remain unsolved.In this paper,we first prove the uniqueness of non-critical periodic traveling fronts.Then,we show that all non-critical periodic traveling fronts are exponentially asymptotically stable.展开更多
基金financially supported by the Key Project of the National Eleventh-Five Year Research Program of China (No.2009BAG12A07)
文摘Copper matrix composites consisting of chromium （Cr） or ferrochrome （Cr-Fe） as strengthening elements and molybdenum disulfide as a lubricant had been sintered in nitrogen and hydrogen atmosphere, respectively. Their morphology and energy-dispersive X-ray spectrometry （EDS） analysis showed that serious interaction occurred between MoS2 and Cr （or Cr-Fe） particles when the samples were sintered in hydrogen atmosphere. Chromium sulfide compound （CrxSy） was formed as a reaction product, which decreased the density and strength of the composites remarkably. This interaction was inhibited when the samples were sintered in nitrogen atmosphere; thus, the mechanical properties of the composites were improved.
基金partially supported by the Natural Science Basic Research Program of Shaanxi(No.2024JCYBMS-025)the Innovation Capability Support Program of Shaanxi(No.2024RS-CXTD-88)。
文摘In this paper,we study a class of time-periodic population model with dispersal.It is well known that the existence of the periodic traveling fronts has been established.However,the uniqueness and stability of such fronts remain unsolved.In this paper,we first prove the uniqueness of non-critical periodic traveling fronts.Then,we show that all non-critical periodic traveling fronts are exponentially asymptotically stable.
