Jajcay's studies( 1993 ; 1994) on the automorphism groups of Cayley maps yielded a new product of groups, which he called, rotary product. Using this product, we define a hyperoperation ⊙ on the group Syme (G) , ...Jajcay's studies( 1993 ; 1994) on the automorphism groups of Cayley maps yielded a new product of groups, which he called, rotary product. Using this product, we define a hyperoperation ⊙ on the group Syme (G) , the stabilizer of the identity e ∈ G in the group Sym (G) . We prove that ( Syme (G) , ⊙) is a hypergroup and characterize the subhypergroups of this hypergroup.Finally, we show that the set of all subhypergroups of Syme ( G ) constitute a lattice under ordinary join and meet and that the minimal elements of order two of this lattice is a subgroup of Aut (G) .展开更多
The electronic structures of TiAl-2M(M=V, Nb, Ta, Cr, Mo, W,Mn) alloy have been investigated using EHT band calculation method. Their bandstructures and average prperties have been obtained. The results show that dopi...The electronic structures of TiAl-2M(M=V, Nb, Ta, Cr, Mo, W,Mn) alloy have been investigated using EHT band calculation method. Their bandstructures and average prperties have been obtained. The results show that doping thetransition metal elements can effectively change the band structure and enable the alloysystem to show the stronger metallic feature. The dopants of V, Cr and Mn increase s-orbital component of Ti and Al in bonding orbital, therefore, there is more sphericalelectronic clound and weakly directional bonds in the crystal, which improve the duictil-ity of the alloy, Nb or Ta makes stronger bonding with Ti and Al, which improvestrength and oxidation resistance of the alloy.展开更多
In this work, we demonstrated a simple and efficacious two-step method for the synthesis of Ag@Au core-shell nanoparticles （Ag@AuNPs） and the Ag/Au hollow nanocages （Ag/AuNCs） with Ag nanoparticles （AgNPs） as se...In this work, we demonstrated a simple and efficacious two-step method for the synthesis of Ag@Au core-shell nanoparticles （Ag@AuNPs） and the Ag/Au hollow nanocages （Ag/AuNCs） with Ag nanoparticles （AgNPs） as seeds by adjusting pH, and the preparation of hybrid Ag@AuNPs- or Ag/AuNCs-graphene oxide nanocomposites （Ag@AuNPs-GO or Ag/AuNCs-GO） based on the self-assembly. It was noticed from the elec- trostatic assembly experiment that the loading amount of Ag/AuNCs on GO nanosheet was more than that of Ag@AuNPs. The as-synthesized hybrid materials were characterized by transmission electron microscopy, atomic force microscopy, ξ-potential, high-angle annular dark- field scanning transmission electron microscopy, thermo- gravimetric analyzer and X-ray diffraction. Catalytic activities of Ag@AuNPs, Ag/AuNCs and Ag/AuNCs-GO nanostructures were investigated in the reduction of 4-, 3-or 2-nitrophenol to 4-, 3- or 2-aminophenol, and on the basis of comparative kinetic studies the following trend was obtained for the related catalytic activity： Ag/AuNCs- GO 〉 Ag/AuNCs 〉 Ag@AuNPs. These observations were attributed to the simultaneous effects of surface area available for catalytic reaction and composition of the hybrid nanostructures.展开更多
文摘Jajcay's studies( 1993 ; 1994) on the automorphism groups of Cayley maps yielded a new product of groups, which he called, rotary product. Using this product, we define a hyperoperation ⊙ on the group Syme (G) , the stabilizer of the identity e ∈ G in the group Sym (G) . We prove that ( Syme (G) , ⊙) is a hypergroup and characterize the subhypergroups of this hypergroup.Finally, we show that the set of all subhypergroups of Syme ( G ) constitute a lattice under ordinary join and meet and that the minimal elements of order two of this lattice is a subgroup of Aut (G) .
文摘The electronic structures of TiAl-2M(M=V, Nb, Ta, Cr, Mo, W,Mn) alloy have been investigated using EHT band calculation method. Their bandstructures and average prperties have been obtained. The results show that doping thetransition metal elements can effectively change the band structure and enable the alloysystem to show the stronger metallic feature. The dopants of V, Cr and Mn increase s-orbital component of Ti and Al in bonding orbital, therefore, there is more sphericalelectronic clound and weakly directional bonds in the crystal, which improve the duictil-ity of the alloy, Nb or Ta makes stronger bonding with Ti and Al, which improvestrength and oxidation resistance of the alloy.
基金Acknowledgments This work was supported by the National Nalural Science Foundation of China （21 105042）, the Science Foundation of China Postdoctor （2014M560572）, the Natural Science Foundation of Shandong Province IZR2015BM024）, and Tai-Shan Scholar Research Fund of Shandong Province. The sludy was partially supported by grant NIH IR01DA037838 to Drs. Li and Nair.
文摘In this work, we demonstrated a simple and efficacious two-step method for the synthesis of Ag@Au core-shell nanoparticles （Ag@AuNPs） and the Ag/Au hollow nanocages （Ag/AuNCs） with Ag nanoparticles （AgNPs） as seeds by adjusting pH, and the preparation of hybrid Ag@AuNPs- or Ag/AuNCs-graphene oxide nanocomposites （Ag@AuNPs-GO or Ag/AuNCs-GO） based on the self-assembly. It was noticed from the elec- trostatic assembly experiment that the loading amount of Ag/AuNCs on GO nanosheet was more than that of Ag@AuNPs. The as-synthesized hybrid materials were characterized by transmission electron microscopy, atomic force microscopy, ξ-potential, high-angle annular dark- field scanning transmission electron microscopy, thermo- gravimetric analyzer and X-ray diffraction. Catalytic activities of Ag@AuNPs, Ag/AuNCs and Ag/AuNCs-GO nanostructures were investigated in the reduction of 4-, 3-or 2-nitrophenol to 4-, 3- or 2-aminophenol, and on the basis of comparative kinetic studies the following trend was obtained for the related catalytic activity： Ag/AuNCs- GO 〉 Ag/AuNCs 〉 Ag@AuNPs. These observations were attributed to the simultaneous effects of surface area available for catalytic reaction and composition of the hybrid nanostructures.
