First-principles calculations have been performed on the structural, electronic, and magnetic properties of seven 3d transition-metal （TM） impurities （V, Cr, Mn, Fe, Co, Ni, and Cu） doped armchair （5,5） and zigz...First-principles calculations have been performed on the structural, electronic, and magnetic properties of seven 3d transition-metal （TM） impurities （V, Cr, Mn, Fe, Co, Ni, and Cu） doped armchair （5,5） and zigzag （8,0） beryllium oxide nanotubes （BeONTs）. The results show that there exists a structural distortion around the 3d TM impurities with respect to the pristine BeONTs. The magnetic moment increases for V- and Cr-doped BeONTs and reaches a maximum for Mn-doped BeONT, and then decreases for Fe-, Co-, Ni-, and Cu-doped BeONTs successively, consistent with the predicted trend of Hund＇s rule to maximize the magnetic moments of the doped TM ions. However, the values of the magnetic moments are smaller than the predicted values of Hund＇s rule due to the strong hybridization between the 2p orbitals of the near O and Be ions of BeONTs and the 3d orbitals of the TM ions. Furthermore, the V-, Co-, and Ni-doped （5,5） and （8,0） BeONTs with half-metal ferromagnetism and thus 100% spin polarization character are good candidates for spintronic applications.展开更多
Genetic comparison between Rhynchophorus ferrugineus （Coleoptera： Curculionidae： Rhynchophorinae） and other four Rhynchophorus spp. such as R. bilineatus, R. phoenicis, R. cruentatus and R. palmarum was investigat...Genetic comparison between Rhynchophorus ferrugineus （Coleoptera： Curculionidae： Rhynchophorinae） and other four Rhynchophorus spp. such as R. bilineatus, R. phoenicis, R. cruentatus and R. palmarum was investigated using partial sequences of Cytochrome c oxidase subunit I （COl） mitochondrial gene. The number ofpolymorphic sites ranged from 79 to 102 while the genetic distances ranged from 0.058 to 0.095. The number of polymorphic sites, genetic distances and phylogenetic relationships among R. ferrugineus and the other four tested species revealed that R.ferrugineus was more closely related to R. bilineatus while it was distantly related to R. palmarum. It is possible to rank the five tested species as follows： R.ferrugineus, R. bilineatus, R. phoenicis, R. cruentatus and R. palmarum. The result of this study is the first step of the revision of the uncertain taxonomic status and phylogenetic relationships among the Rhynchophorus genus. Further analysis should be performed using other Rhynchophorus species as well as other molecular markers.展开更多
The main aspects of a gauge-invariant approach to the description of quark dynamics in the nonperturbative regime of quantum chromodynamics （QC, D） are first reviewed. The role of the parallel transport operation in...The main aspects of a gauge-invariant approach to the description of quark dynamics in the nonperturbative regime of quantum chromodynamics （QC, D） are first reviewed. The role of the parallel transport operation in constructing gauge-invariant Green＇s functions is then presented, and the relevance of Wilson loops for the representation of the interaction is emphmsized. Recent developments, based on the use of polygonal lines for the parallel transport operation, are presented. An integro-differential equation, obtained for the qua.rk Green＇s function defined with a phase factor along a single, straight line segment, is solved exactly and analytically in the case of two-dimensional QCD in the large-Nc, limit. The solution displays the dynamical mass generation phenomenon for quarks, with an infinite number of branch-cut singularities that are stronger than simple poles.展开更多
We present a domain decomposition method （DDM） devoted to the iterative solution of time-harmonic electromagnetic scattering problems, involving large and resonant cavities. This DDM uses the electric field integral...We present a domain decomposition method （DDM） devoted to the iterative solution of time-harmonic electromagnetic scattering problems, involving large and resonant cavities. This DDM uses the electric field integral equation （EFIE） for the solution of Maxwell problems in both interior and exterior subdomains, and we propose a simple preconditioner for the global method, based on the single layer operator restricted to the fictitious interface between the two subdomains.展开更多
基金Project supported by the National Basic Research Program of China （Grant No. 2010CB631002） and the National Natural Science Foundation of China （Grant Nos. 51071098, 11104175, and 11214216）.
文摘First-principles calculations have been performed on the structural, electronic, and magnetic properties of seven 3d transition-metal （TM） impurities （V, Cr, Mn, Fe, Co, Ni, and Cu） doped armchair （5,5） and zigzag （8,0） beryllium oxide nanotubes （BeONTs）. The results show that there exists a structural distortion around the 3d TM impurities with respect to the pristine BeONTs. The magnetic moment increases for V- and Cr-doped BeONTs and reaches a maximum for Mn-doped BeONT, and then decreases for Fe-, Co-, Ni-, and Cu-doped BeONTs successively, consistent with the predicted trend of Hund＇s rule to maximize the magnetic moments of the doped TM ions. However, the values of the magnetic moments are smaller than the predicted values of Hund＇s rule due to the strong hybridization between the 2p orbitals of the near O and Be ions of BeONTs and the 3d orbitals of the TM ions. Furthermore, the V-, Co-, and Ni-doped （5,5） and （8,0） BeONTs with half-metal ferromagnetism and thus 100% spin polarization character are good candidates for spintronic applications.
文摘Genetic comparison between Rhynchophorus ferrugineus （Coleoptera： Curculionidae： Rhynchophorinae） and other four Rhynchophorus spp. such as R. bilineatus, R. phoenicis, R. cruentatus and R. palmarum was investigated using partial sequences of Cytochrome c oxidase subunit I （COl） mitochondrial gene. The number ofpolymorphic sites ranged from 79 to 102 while the genetic distances ranged from 0.058 to 0.095. The number of polymorphic sites, genetic distances and phylogenetic relationships among R. ferrugineus and the other four tested species revealed that R.ferrugineus was more closely related to R. bilineatus while it was distantly related to R. palmarum. It is possible to rank the five tested species as follows： R.ferrugineus, R. bilineatus, R. phoenicis, R. cruentatus and R. palmarum. The result of this study is the first step of the revision of the uncertain taxonomic status and phylogenetic relationships among the Rhynchophorus genus. Further analysis should be performed using other Rhynchophorus species as well as other molecular markers.
文摘The main aspects of a gauge-invariant approach to the description of quark dynamics in the nonperturbative regime of quantum chromodynamics （QC, D） are first reviewed. The role of the parallel transport operation in constructing gauge-invariant Green＇s functions is then presented, and the relevance of Wilson loops for the representation of the interaction is emphmsized. Recent developments, based on the use of polygonal lines for the parallel transport operation, are presented. An integro-differential equation, obtained for the qua.rk Green＇s function defined with a phase factor along a single, straight line segment, is solved exactly and analytically in the case of two-dimensional QCD in the large-Nc, limit. The solution displays the dynamical mass generation phenomenon for quarks, with an infinite number of branch-cut singularities that are stronger than simple poles.
文摘We present a domain decomposition method （DDM） devoted to the iterative solution of time-harmonic electromagnetic scattering problems, involving large and resonant cavities. This DDM uses the electric field integral equation （EFIE） for the solution of Maxwell problems in both interior and exterior subdomains, and we propose a simple preconditioner for the global method, based on the single layer operator restricted to the fictitious interface between the two subdomains.
