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Search Results: 1 - 10 of 160527 matches for " H. Cao "
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An Improved Storage Structure Format for VCF Standard  [PDF]
Qi Cao, H. J. Cai, Tianqi Cai
Journal of Software Engineering and Applications (JSEA) , 2013, DOI: 10.4236/jsea.2013.611070
Abstract:

The Visiting Card Format (VCF) has already been widely used in mobile devices and personal computers (PC). Many mobile manufacturers have developed visiting card recognition systems by using Optical Character Recognition (OCR) technology, which can convert and save the information on the paper cards. However, the inaccuracy of OCR always leads to error in recognition, and it only seizes text information, ignoring images. Our research is to solve that problem based on the vCard format by creating a new VCF, vCardPackage, which contains both textual and pictorial information. It consists of a layout layer, a text content layer, a resource layer and a template layer. The design combines content, layout and images together, and enables users to view or modify mobile devices. The XML storage structure is adopted in the vCardPackage, which is compatible with VCF data, so that the original data can be stored completely when shared or transferred.

Wave interference effect on polymer microstadium laser
W. Fang,H. Cao
Physics , 2007, DOI: 10.1063/1.2762285
Abstract: We investigate the lasing modes in fully chaotic polymer microstadiums under optical pumping. The lasing modes are regularly spaced in frequency, and their amplitudes oscillate with frequency. Our numerical simulations reveal that the lasing modes are multi-orbit scar modes. The interference of partial waves propagating along the constituent orbits results in local maxima of quality factor at certain frequencies. The observed modulation of lasing mode amplitude with frequency results from the variation of quality factor, which provides the direct evidence of wave interference effect in open chaotic microcavities.
The nature and line shapes of charmonium in the $e^+e^- \to D\bar{D}$ reactions
Xu Cao,H. Lenske
Physics , 2014,
Abstract: We explore the nature of sharp resonances with asymmetric line shape observed in cross section data, a general physical phenomenon produced by the interference of continuum background and resonances. A Fano scheme and the coupled-channel T-matrix approach are employed to this aim and their close relationship is present. As a typical example, we point out that the $\psi(3770)$ state observed in the $e^+e^-$ reactions with an anomalous line shape can be explained naturally as a resonance embedded in the $D\bar{D}$ continuum. From a coupled-channels analysis the background of $\psi(3770)$ resonance is found to originate from a pole at $\sqrt{s}=3716.0 \pm$ 30.0~MeV. As a by-product, the broad structure $X(3900)/G(3900)$ seen in the Belle data, is found to be the tail of the $\psi(3770)$ state, distorted by the opening of the $D^*\bar{D} + c.c$ channel and the onset of the $\psi(4040)$ spectral distribution, thus making the assignment as a genuine charmonium state unlikely.
A covariantly foliated higher dimensional space-time: Implications for short distance gravity and BSM physics
Cao H. Nam
Physics , 2014,
Abstract: We consider the space-time at short distances in which it is described by a $D$-dimensional manifold (bulk) carrying out the principal bundle structure. As a result, this space-time manifold is foliated in the covariant way by the $(D-4)$-dimensional submanifolds, realized as the space-like internal spaces, that are smooth copies of the Lie group $G$ considered in this paper as the special unitary group. The submanifolds being transversal to the internal spaces are realized as the external spaces and in fact identified as the usual $4$-dimensional world. The fundamental degrees of freedom determining the geometrical dynamics of the bulk corresponding with short distance gravity are given by the gauge fields, the external metric field and the modulus fields setting dynamically the volume of the internal spaces. These gauge fields laying the bulk is to point precisely out the local directions of the external spaces which depend on the topological non-triviality of the space-time principal bundle. The physical size of the internal spaces is fixed dynamically by the moduli stabilization potential which completely arise from the intrinsic geometry of the bulk. A detail description of the low energy bulk gravity in the weak field limit is given around the classical ground state of the bulk. Additionally, we investigate the dynamics of the fundamentally $4$-dimensional Weyl spinor fields and the fields of carrying out the non-trivial representations of the Lie group $G$ propagating in the bulk in a detail study. These results suggest naturally the possible solutions to some the experimental problems of Standard Model, the smallness of the observed neutrino masses and a dark matter candidate.
Gauge theory of quantum gravity
Cao H. Nam
Physics , 2014,
Abstract: The gravity is classically formulated as the geometric curvature of the space-time in general relativity which is completely different from the other well-known physical forces. Since seeking a quantum framework for the gravity is a great challenge in physics. Here we present an alternative construction of quantum gravity in which the quantum gravitational degrees of freedom are described by the non-Abelian gauge fields characterizing topological non-triviality of the space-time. The quantum dynamics of the space-time thus corresponds to the superposition of the distinct topological states. Its unitary time evolution is described by the path integral approach. This result will also be suggested to solve some major problems in physics of the black holes.
Charmonium resonances and Fano line shapes
Xu Cao,H. Lenske
Physics , 2014,
Abstract: Anomalous line shapes of quarkonia are explained naturally as an interference effect of a $c\bar c$ confined closed channel with the surrounding continua, well established in other fields of physics as Fano-resonances. We discuss a quark model coupled-channel analysis describing quarkonium as a mixing of closed $Q\bar Q$ and molecular-like $D\bar D$ open channels. The asymmetric line shapes observed in $\psi(3770)$ production cross sections in $e^+e^-$ annihilation to $D^0\bar{D}^0$ and $D^+ D^-$, respectively, are described very well. The method allows to extract directly from the data the amount of $Q\bar Q \leftrightarrow D\bar D$ configuration mixing.
Statistics of random lasing modes and amplified spontaneous emission spikes in weakly scattering systems
X. Wu,H. Cao
Physics , 2007,
Abstract: We have measured the spectral correlations and intensity statistics of random lasing modes in weakly scattering systems, and compared them to those of the amplified spontaneous emission spikes. Their dramatic differences revealed the distinct physical mechanisms. We find that local excitation of a weakly scattering system may greatly reduce the number of lasing modes even without absorption outside the pumped region. The lasing modes can be very different from the quasimodes of the passive system due to selective amplification of the feedback from the scatterers within the local gain region.
Instability of an accretion disk with a magnetically driven wind
Xinwu Cao,H. C. Spruit
Physics , 2001, DOI: 10.1051/0004-6361:20011818
Abstract: We present a linear analysis of the stability of accretion disks in which angular momentum is removed by the magnetic torque exerted by a centrifugally driven wind. The effects of the dependence of the wind torque on field strength and inclination, the sub-Keplerian rotation due to magnetic forces, and the compression of the disk by the field are included. A WKB dispersion relation is derived for the stability problem. We find that the disk is always unstable if the wind torque is strong. At lower wind torques instability also occurs provided the rotation is close to Keplerian. The growth time scale of the instability can be as short as the orbital time scale. The instability is mainly the result of the sensitivity of the mass flux to changes in the inclination of the field at the disk surface. Magnetic diffusion in the disk stabilizes if the wind torque is small.
The large scale magnetic fields of thin accretion disks
Xinwu Cao,H. C. Spruit
Physics , 2013, DOI: 10.1088/0004-637X/765/2/149
Abstract: Large scale magnetic field threading an accretion disk is a key ingredient in the jet formation model. The most attractive scenario for the origin of such a large scale field is the advection of the field by the gas in the accretion disk from the interstellar medium or a companion star. However, it is realized that outward diffusion of the accreted field is fast compared to the inward accretion velocity in a geometrically thin accretion disk if the value of the Prandtl number Pm is around unity. In this work, we revisit this problem considering the angular momentum of the disk is removed predominantly by the magnetically driven outflows. The radial velocity of the disk is significantly increased due to the presence of the outflows. Using a simplified model for the vertical disk structure, we find that even moderately weak fields can cause sufficient angular momentum loss via a magnetic wind to balance outward diffusion. There are two equilibrium points, one at low field strengths corresponding to a plasma-beta at the midplane of order several hundred, and one for strong accreted fields, beta~1. We surmise that the first is relevant for the accretion of weak, possibly external, fields through the outer parts of the disk, while the latter one could explain the tendency, observed in full 3D numerical simulations, of strong flux bundles at the centers of disk to stay confined in spite of strong MRI turbulence surrounding them.
Bornoligies, Topological Games and Function Spaces
Jiling Cao,Artur H. Tomita
Mathematics , 2014,
Abstract: In this paper, we continue the study of function spaces equipped with topologies of (strong) uniform convergence on bornologies initiated by Beer and Levi \cite{beer-levi:09}. In particular, we investigate some topological properties these function spaces defined by topological games. In addition, we also give further characterizations of metrizability and completeness properties of these function spaces.
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