Based on the concept of adiabatic invariant, the perturbation to unified symmetry and adiabatic invariants for relativistic Hamilton systems are studied. The definition of the perturbation to unified symmetry for the ...Based on the concept of adiabatic invariant, the perturbation to unified symmetry and adiabatic invariants for relativistic Hamilton systems are studied. The definition of the perturbation to unified symmetry for the system is presented, and the criterion of the perturbation to unified symmetry is given. Meanwhile, the Noether adiabatic invariants, the generalized Hojman adiabatic invariants, and the Mei adiabatic invariants for the perturbed system are obtained.展开更多
In this article, by means of the theory of majorization, Adamovic's inequality is extended to the cases of the general elementary symmetric functions and its duals, and the refined and reversed forms are also give...In this article, by means of the theory of majorization, Adamovic's inequality is extended to the cases of the general elementary symmetric functions and its duals, and the refined and reversed forms are also given. As applications, some new inequalities for simplex are established.展开更多
A new chiral monomer,(S)‐5,5′‐divinyl‐BINAP,was successfully synthesized and embedded intotwo different porous organic polymers(Poly‐1and Poly‐2).After loading a Rh species,the catalystswere applied for the hete...A new chiral monomer,(S)‐5,5′‐divinyl‐BINAP,was successfully synthesized and embedded intotwo different porous organic polymers(Poly‐1and Poly‐2).After loading a Rh species,the catalystswere applied for the heterogeneous asymmetric hydroformylation of styrene.Compared with thehomogeneous BINAP analogue,the enantioselectivity of Rh/Poly‐1catalyst was drastically increasedby approximately70%.The improved enantioselectivity of the porous Rh/BINAP polymerswas attributed to the presence of flexible chiral nanopockets resulting from the increased bulk ofthe R groups near the catalytic center.展开更多
Developing chiral solid catalysts for asymmetric catalysis is desirable for the elimination of homogeneous catalysis flaws but remains an immense challenge.Herein,we report the immobilization of TsDPEN on SBA‐15 with...Developing chiral solid catalysts for asymmetric catalysis is desirable for the elimination of homogeneous catalysis flaws but remains an immense challenge.Herein,we report the immobilization of TsDPEN on SBA‐15 with an ionic liquid(IL)linkage via the one‐pot reaction of imidazole‐TsDPEN‐N‐Boc with 3‐(trimethoxysilyl)propyl bromide in the SBA‐15 mesopores.After coordination to Rh,the chiral solid catalysts could efficiently catalyze quinoline transfer hydrogenation,achieving 97%conversion with 93%ee,which was comparable to their homogeneous counterparts.The chiral solid catalyst with the IL linkage afforded much higher turnover frequency than that without the IL linkage(93 h^(–1)vs.33 h^(–1)),attributed to the phase transfer and formate‐enriching ability of the IL linkage.Furthermore,the effect of the pH on the reaction rate of the solid catalyst was investigated,preventing reaction rate retardation during the catalytic process.The tuning of the linkage group is an efficient approach for catalytic activity improvement of immobilized chiral catalysts.展开更多
We investigate the symmetry reduction for the two-dimensional incompressible Navier-Stokes equationin conventional stream function form through Lie symmetry method and construct some similarity reduction solutions.Two...We investigate the symmetry reduction for the two-dimensional incompressible Navier-Stokes equationin conventional stream function form through Lie symmetry method and construct some similarity reduction solutions.Two special cases in [D.K.Ludlow,P.A.Clarkson,and A.P.Bassom,Stud.Appl.Math.103 (1999) 183] and a theoremin [S.Y.Lou,M.Jia,X.Y.Tang,and F.Huang,Phys.Rev.E 75 (2007) 056318] are retrieved.展开更多
An efficient identification algorithm is given for commensurate order linear time-invariant fractional systems. This algorithm can identify not only model coefficients of the system, but also its differential order at...An efficient identification algorithm is given for commensurate order linear time-invariant fractional systems. This algorithm can identify not only model coefficients of the system, but also its differential order at the same time. The basic idea is to change the system matrix into a diagonal one through basis transformation. This makes it possible to turn the system’s input-output relationships into the summation of several simple subsystems, and after the identification of these subsystems, the whole identification system is obtained which is algebraically equivalent to the former system. Finally an identification example verifies the effectiveness of the method previously mentioned.展开更多
Although weakly interacting massive particle （WIMP） scenario is very well motivated, it is not guaran- teed to be the truth. It is important to keep mind open and consider other well-motivated scenarios. In this pap...Although weakly interacting massive particle （WIMP） scenario is very well motivated, it is not guaran- teed to be the truth. It is important to keep mind open and consider other well-motivated scenarios. In this paper, we briefly review several possible non-WIMP dark matter （DM） candidates. First, we discuss details on asymmetric DM models, in which the baryon asymmetry in standard model sector is related to the asymmetry in DM sector. We discuss how DM relic abundance is determined in such models. Also we cover the possible interesting ex- perimental signatures induced by its asymmetric nature. Then we consider ultralight DM candidates, i.e., axion and dark photon. In such scenarios, DM should be treated as a coherently oscillating background, instead of each individual particle. Searching strategies for such DM candidates is very different than those in conventional DM models. We discuss several interesting experiments looking for these ultralight particles. We also cover interesting subtleties encountered in those experiments.展开更多
A generalized scheme for the construction of coherent states in the context of position-dependent effective mass systems has been presented. This formalism is based on the ladder operators and associated algebra of th...A generalized scheme for the construction of coherent states in the context of position-dependent effective mass systems has been presented. This formalism is based on the ladder operators and associated algebra of the system which are obtained using the concepts of supersymmetric quantum mechanics and the property of shape invariance. In order to exemplify the general results and to analyze the properties of the coherent states, several examples have been considered.展开更多
文摘Based on the concept of adiabatic invariant, the perturbation to unified symmetry and adiabatic invariants for relativistic Hamilton systems are studied. The definition of the perturbation to unified symmetry for the system is presented, and the criterion of the perturbation to unified symmetry is given. Meanwhile, the Noether adiabatic invariants, the generalized Hojman adiabatic invariants, and the Mei adiabatic invariants for the perturbed system are obtained.
文摘In this article, by means of the theory of majorization, Adamovic's inequality is extended to the cases of the general elementary symmetric functions and its duals, and the refined and reversed forms are also given. As applications, some new inequalities for simplex are established.
基金supported by the Strategic priority Research Program of the Chinese Academy of Sciences (XDB17020400)~~
文摘A new chiral monomer,(S)‐5,5′‐divinyl‐BINAP,was successfully synthesized and embedded intotwo different porous organic polymers(Poly‐1and Poly‐2).After loading a Rh species,the catalystswere applied for the heterogeneous asymmetric hydroformylation of styrene.Compared with thehomogeneous BINAP analogue,the enantioselectivity of Rh/Poly‐1catalyst was drastically increasedby approximately70%.The improved enantioselectivity of the porous Rh/BINAP polymerswas attributed to the presence of flexible chiral nanopockets resulting from the increased bulk ofthe R groups near the catalytic center.
文摘Developing chiral solid catalysts for asymmetric catalysis is desirable for the elimination of homogeneous catalysis flaws but remains an immense challenge.Herein,we report the immobilization of TsDPEN on SBA‐15 with an ionic liquid(IL)linkage via the one‐pot reaction of imidazole‐TsDPEN‐N‐Boc with 3‐(trimethoxysilyl)propyl bromide in the SBA‐15 mesopores.After coordination to Rh,the chiral solid catalysts could efficiently catalyze quinoline transfer hydrogenation,achieving 97%conversion with 93%ee,which was comparable to their homogeneous counterparts.The chiral solid catalyst with the IL linkage afforded much higher turnover frequency than that without the IL linkage(93 h^(–1)vs.33 h^(–1)),attributed to the phase transfer and formate‐enriching ability of the IL linkage.Furthermore,the effect of the pH on the reaction rate of the solid catalyst was investigated,preventing reaction rate retardation during the catalytic process.The tuning of the linkage group is an efficient approach for catalytic activity improvement of immobilized chiral catalysts.
基金Supported by National Natural Science Foundations of China under Grant Nos.10735030,10475055,10675065,and 90503006National Basic Research Program of China (973 Program) under Grant No.2007CB814800+2 种基金PCSIRT (IRT0734)the Research Fund of Postdoctoral of China under Grant No.20070410727Specialized Research Fund for the Doctoral Program of Higher Education under Grant No.20070248120
文摘We investigate the symmetry reduction for the two-dimensional incompressible Navier-Stokes equationin conventional stream function form through Lie symmetry method and construct some similarity reduction solutions.Two special cases in [D.K.Ludlow,P.A.Clarkson,and A.P.Bassom,Stud.Appl.Math.103 (1999) 183] and a theoremin [S.Y.Lou,M.Jia,X.Y.Tang,and F.Huang,Phys.Rev.E 75 (2007) 056318] are retrieved.
基金Sponsored by 863 Project (Grant No.2002AA517020) Developing Fund of Shanghai Science Committee (Grant No.011607033).
文摘An efficient identification algorithm is given for commensurate order linear time-invariant fractional systems. This algorithm can identify not only model coefficients of the system, but also its differential order at the same time. The basic idea is to change the system matrix into a diagonal one through basis transformation. This makes it possible to turn the system’s input-output relationships into the summation of several simple subsystems, and after the identification of these subsystems, the whole identification system is obtained which is algebraically equivalent to the former system. Finally an identification example verifies the effectiveness of the method previously mentioned.
文摘Although weakly interacting massive particle （WIMP） scenario is very well motivated, it is not guaran- teed to be the truth. It is important to keep mind open and consider other well-motivated scenarios. In this paper, we briefly review several possible non-WIMP dark matter （DM） candidates. First, we discuss details on asymmetric DM models, in which the baryon asymmetry in standard model sector is related to the asymmetry in DM sector. We discuss how DM relic abundance is determined in such models. Also we cover the possible interesting ex- perimental signatures induced by its asymmetric nature. Then we consider ultralight DM candidates, i.e., axion and dark photon. In such scenarios, DM should be treated as a coherently oscillating background, instead of each individual particle. Searching strategies for such DM candidates is very different than those in conventional DM models. We discuss several interesting experiments looking for these ultralight particles. We also cover interesting subtleties encountered in those experiments.
文摘A generalized scheme for the construction of coherent states in the context of position-dependent effective mass systems has been presented. This formalism is based on the ladder operators and associated algebra of the system which are obtained using the concepts of supersymmetric quantum mechanics and the property of shape invariance. In order to exemplify the general results and to analyze the properties of the coherent states, several examples have been considered.
