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Periodic Wall Blow/Suction Perturbation Evolution in Turbulent Boundary Layer  [PDF]
Gangli Hao, Nan Jiang
Applied Mathematics (AM) , 2012, DOI: 10.4236/am.2012.39153
Abstract: Time sequence signals of instantaneous longitudinal and normal velocity components at different longitudinal and normal positions in a turbulent boundary layer have been finely measured simultaneously by IFA300 constant temperature anemometer and double-sensor hot-wire probe with sampling resolution higher than the frequency that corresponds to the smallest time scale of Kolmogorov dissipation scale before/after introducing artificial periodic blow/suction perturbation. The period-phase-average technique is applied to extract the periodic waveforms of artificial perturbation from instantaneous time sequence signals of longitudinal and normal turbulence background. Experimental investigation is carried out on the attenuation characteristics of periodic perturbation wave with different frequency along longitudinal direction and normal direction in a turbulent boundary layer. The amplitude distributions of longitudinal and normal disturbing velocity component for different perturbation frequencies are measured at different downstream and normal positions in turbulent boundary layer. The amplitude growth rate of artificial periodic perturbation wave is calculated according to flow instability theory. The experimental results are compared and in consistent with the theoretical and numerical results.
New Physics and Single Top Production
Yu, Jiang-Hao
High Energy Physics - Phenomenology , 2013,
Abstract: We show how single top production in conjunction with a variety of additional final states provides a sensitive probe of new physics. We investigate several new physics scenarios such as lepto-phobic W' model, and exotic B' model, and then perform detailed simulation analyses in s-, and tW-associated production channels.
Generalized Jarzynski's equality of inhomogeneous multidimensional diffusion processes
Hao Ge,Daquan Jiang
Physics , 2009,
Abstract: Applying the well-known Feynman-Kac formula of inhomogeneous case, an interesting and rigorous mathematical proof of generalized Jarzynski's equality of inhomogeneous multidimensional diffusion processes is presented, followed by an extension of the second law of thermodynamics. Then, we explain its physical meaning and applications, extending Hummer and Szabo's work ({\em Proc. Natl. Acad. Sci. USA} {\bf 98}(7), 3658--3661 (2001)) and Hatano-Sasa equality of steady state thermodynamics ({\em Phys. Rev. Lett.} {\bf 86}, 3463--3466 (2001)) to the general multidimensional case.
Vector Fermion-Portal Dark Matter: Direct Detection and Galactic Center Gamma-Ray Excess
Jiang-Hao Yu
Physics , 2014, DOI: 10.1103/PhysRevD.90.095010
Abstract: We investigate a neutral gauge boson X originated from a hidden U(1) extension of the standard model as the particle dark matter candidate. The vector dark matter interacts with the standard model fermions through heavy fermion mediators. The interactions give rise to t-channel annihilation cross section in the XX to ff process, which dominates the thermal relic abundance during thermal freeze-out and produces measurable gamma-ray flux in the galactic halo. For a light vector dark matter, if it predominantly couples to the third generation fermions, this model could explain the excess of gamma rays from the galactic center. We show that the vector dark matter with a mass of 20 ~ 40 GeV and that annihilate into the bb and tautau final states provides an excellent description of the observed gamma-ray excess. The parameter space aimed at explaining the gamma-ray excess, could also provide the correct thermal relic density and is compatible with the constraints from electroweak precision data, Higgs invisible decay, and collider searches. We also show the dark matter couplings to the nucleon from the fermion portal interactions are loop-suppressed, and only contribute to the spin-dependent cross section. So the vector dark matter could easily escape the stringent constraints from the direct detection experiments.
Global solution to the drift-diffusion-Poisson system for semiconductors with nonlinear recombination-generation rate
Hao Wu,Jie Jiang
Mathematics , 2011,
Abstract: In this paper, we study the Cauchy problem of a time-dependent drift-diffusion-Poisson system for semiconductors. Existence and uniqueness of global weak solutions are proven for the system with a higher-order nonlinear recombination-generation rate R. We also show that the global weak solution will converge to a unique equilibrium as time tends to infinity.
A trace formula for the forcing relation of braids
Boju Jiang,Hao Zheng
Mathematics , 2005, DOI: 10.1016/j.top.2007.06.002
Abstract: The forcing relation of braids has been introduced for a 2-dimensional analogue of the Sharkovskii order on periods for maps of the interval. In this paper, by making use of the Nielsen fixed point theory and a representation of braid groups, we deduce a trace formula for the computation of the forcing order.
Cohomological support loci of varieties of Albanese fiber dimension one
Zhi Jiang,Hao Sun
Mathematics , 2011,
Abstract: Let $X$ be a smooth projective variety of Albanese fiber dimension 1 and of general type. We prove that the translates through 0 of all components of $V^0(\omega_X)$ generate $\Pic^0(X)$. We then study the pluricanonical maps of $X$. We show that $|4K_X|$ induces a birational map.
Comparative Study on Electromagnetic and Electrome-chanical Transient Model for Grid-connected Photovoltaic Power System  [PDF]
Man Zhang, Hao Sun, Zhigang Chen, Xiaorong Xie, Qirong Jiang
Energy and Power Engineering (EPE) , 2013, DOI: 10.4236/epe.2013.54B048
Abstract: With the development of new energy technology, there are increasing applications of grid-connected photovoltaic power generation system. However, there is little research on development of electromechanical model of large scale photovoltaic power station. The computational speed will be very slow if electromagnetic transient model is used for stability study because of its complexity. Therefore, study on electromechanical transient model of grid-connected photovoltaic power generation system is of great meaning. In this paper, electromagnetic transient model of photovoltaic power generation system is introduced first, and then a general electromechanical transient model is proposed. These two kinds of simulation model are set up in PSCAD. By comparing the simulation results of two models, the correctness and validity of the electromechanical transient model is verified. It provides reference model for efficient simulation and modeling of grid-connected photovoltaic power station in large-scale power systems.
The Recognition of CAPTCHA  [PDF]
Min Wang, Tianhui Zhang, Wenrong Jiang, Hao Song
Journal of Computer and Communications (JCC) , 2014, DOI: 10.4236/jcc.2014.22003
Abstract:

CAPTCHA is a completely automated program designed to distinguish whether the user is a computer or human. As the problems of Internet security are worsening, it is of great significance to do research on CAPTCHA. This article starts from the recognition of CAPTCHAs, then analyses the weaknesses in its design and gives corresponding recognition proposals according to various weaknesses, finally offers suggestions related to the improvement of CAPTCHAs. Firstly, this article briefly introduces the basic steps during the decoding process and their principles. And during each step we choose methods which are better adapted to the features of different CAPTCHA images. Methods chosen are as followings: bimodal method in binarization, improved corrosion algorithm in denoising, projection segmentation method in denoised image processing and SVM in recognition. Then, we demonstrate detailed process through the samples taken from the online registration system of ICBC, show the recognition effect and correct the results according to the statistical data in the process. This article decodes CAPTCHAS from three other large banks in the same way but just provides the recognition results. Finally, this article offers targeted suggestions to the four banks based on the recognition effect and analysis process stated above.

An Improved Iterative Closest Points Algorithm  [PDF]
Hao Yang, Jialan Jiang, Guowei Zhao, Jie Zhao
World Journal of Engineering and Technology (WJET) , 2015, DOI: 10.4236/wjet.2015.33C045
Abstract:

Visual method including binocular stereo vision method and monocular vision method of the relative position and pose measurement for space target has become relatively mature, and many researchers focus on the method based on three-dimension measurement recently. ICP alignment, which is the key of three-dimension pattern measurement method, has the problem of low efficiency in large data sets. Considering this problem, an improved ICP algorithm is proposed in this paper. The improved ICP algorithm is the combination of the original ICP algorithm and KD-TREE. The experimental comparison between the improved ICP algorithm and the traditional ICP algorithm in efficiency has been given in this paper, which shows that the improved ICP algorithm can get much better performance.

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