There is a deviation between actual and theoretical perceived positions of virtual object in stereoscop-ic display.Therefore,methods for precise position perception in real world are proposed in this paper.The causes ...There is a deviation between actual and theoretical perceived positions of virtual object in stereoscop-ic display.Therefore,methods for precise position perception in real world are proposed in this paper.The causes for the deviation are analyzed on the basis of geometrical optics .Then deviation correctionsare performed by error compensation with mathematic method and by remodeling virtual viewpoint dynami-cally with the movement of physical viewpoint.Experimental results show that these methods can reducethe position deviation to less than 10 millimeter,meeting the requirements for direct manipulation in mul-ti-sensory virtual environment.展开更多
We revisit the quantum decoherence problem of the center of mass motion of a macroscopic object, which is modelled as a one-dimensional atom chain. Induced by the coupling of the center of mass （C.M） motion with the...We revisit the quantum decoherence problem of the center of mass motion of a macroscopic object, which is modelled as a one-dimensional atom chain. Induced by the coupling of the center of mass （C.M） motion with the inner degrees of freedom, this inner-environment-induced decoherence is reflected by the localization of the C.M wave packet. We show that, the C.M motion is coupled to the inner states only when the chain has interaction with the external potential. This result provides a realistic mechanism for the analysis of the inner-environment-induced localization of a macroscopic object.展开更多
The production of Bc and B＊ mesons at a Z-factory （an e＋e- collider operating at energies around the Z pole） is calculated up to the next-to-leading order （NLO） QCD accuracy. The results show that the dependence...The production of Bc and B＊ mesons at a Z-factory （an e＋e- collider operating at energies around the Z pole） is calculated up to the next-to-leading order （NLO） QCD accuracy. The results show that the dependence of the total cross sections on the renormalization scale/1 is suppressed by the corrections, and the NLO corrections enhance the total cross sections of B,. by 52% and of Bc＊ by 33% when the renormalization scale is taken at μ = 2mb. To observe the various behaviors of the production of the mesons Bc and Bc＊, such as the differential cross section vs. the out-going angle, the forward-backward asymmetry, and the distribution vs. the energy fraction z up to NLO QCD accuracy as well as the relevant K-factor （NLO to LO） for the production, are calculated, and it is pointed out that some of the observables obtained in the present work may be used as a specific precision test of the standard model.展开更多
基金supported by the National Natural Science Foundation of China(No.60674052)
文摘There is a deviation between actual and theoretical perceived positions of virtual object in stereoscop-ic display.Therefore,methods for precise position perception in real world are proposed in this paper.The causes for the deviation are analyzed on the basis of geometrical optics .Then deviation correctionsare performed by error compensation with mathematic method and by remodeling virtual viewpoint dynami-cally with the movement of physical viewpoint.Experimental results show that these methods can reducethe position deviation to less than 10 millimeter,meeting the requirements for direct manipulation in mul-ti-sensory virtual environment.
基金The project supported by National Natural Science Foundation of China under Grant Nos. 10547106, 90203018, 10474104, and 60433050, and the National Fundamental Research Program of China under Grant Nos. 2001CB309310 and 2005CB724508 L. Zheng thanks sincerely C.P. Sun and P. Zhang for their helpful discussions.
文摘We revisit the quantum decoherence problem of the center of mass motion of a macroscopic object, which is modelled as a one-dimensional atom chain. Induced by the coupling of the center of mass （C.M） motion with the inner degrees of freedom, this inner-environment-induced decoherence is reflected by the localization of the C.M wave packet. We show that, the C.M motion is coupled to the inner states only when the chain has interaction with the external potential. This result provides a realistic mechanism for the analysis of the inner-environment-induced localization of a macroscopic object.
基金supported by the National Natural Science Foundation of China(Grant Nos.11275243,11275036,11447601,11535002,and 11675239)
文摘The production of Bc and B＊ mesons at a Z-factory （an e＋e- collider operating at energies around the Z pole） is calculated up to the next-to-leading order （NLO） QCD accuracy. The results show that the dependence of the total cross sections on the renormalization scale/1 is suppressed by the corrections, and the NLO corrections enhance the total cross sections of B,. by 52% and of Bc＊ by 33% when the renormalization scale is taken at μ = 2mb. To observe the various behaviors of the production of the mesons Bc and Bc＊, such as the differential cross section vs. the out-going angle, the forward-backward asymmetry, and the distribution vs. the energy fraction z up to NLO QCD accuracy as well as the relevant K-factor （NLO to LO） for the production, are calculated, and it is pointed out that some of the observables obtained in the present work may be used as a specific precision test of the standard model.
