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Results for "S. Zhang"

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Triple α Resonances in the Decay of Hot Nuclear Systems *Mar 23 2019The Efimov (Thomas) trimers in excited 12 C nuclei, for which no observation exists yet, are discussed by means of analyzing the experimental data of 70(64) Zn( 64 Ni) + 70(64) Zn( 64 Ni) reactions at beam energy of E/A=35MeV/nucleon. In heavy ion collisions, ... More
Bounds on volume growth of geodesic balls under Ricci flowJul 21 2011Oct 09 2011We prove a so called $\kappa$ non-inflating property for Ricci flow, which provides an upper bound for volume ratio of geodesic balls over Euclidean ones, under an upper bound for scalar curvature. This result can be regarded as the opposite statement ... More
Precise Algorithm to Generate Random Sequential Addition of Hard Hyperspheres at SaturationFeb 20 2014Random sequential addition (RSA) time-dependent packing process, in which congruent hard hyperspheres are randomly and sequentially placed into a system without interparticle overlap, is a useful packing model to study disorder in high dimensions. Of ... More
Lie transform perturbation theory based on Lagrangian one-formJul 28 2016As a method different from canonical perturbation transform based on Hamilton-Jacob equation and Lie perturbation transform based on motion equation given by Deprit, Lie transform perturbation theory based on Lagrangian 1-form is explored for its wide ... More
Convective overshoot mixing in stellar interior modelsMar 01 2013The convective overshoot mixing plays an important role in stellar structure and evolution. However, the overshoot mixing is a long standing problem. The uncertainty of the overshoot mixing is one of the most uncertain factors in stellar physics. As it ... More
Spin diffusion at finite electric and magnetic fieldsNov 28 2002Spin transport properties at finite electric and magnetic fields are studied by using the generalized semiclassical Boltzmann equation. It is found that the spin diffusion equation for non-equilibrium spin density and spin currents involves a number of ... More
When does a Schrödinger heat equation permit positive solutionsJan 24 2006We introduce some new classes of time dependent functions whose defining properties take into account of oscillations around singularities. We study properties of solutions to the heat equation with coefficients in these classes which are much more singular ... More
A simple scheme to implement a nonlocal turbulent convection model for the convective overshoot mixingJan 08 2016The classical 'ballistic' overshoot models show some contradictions and are not consistence with numerical simulations and asteroseismic studies. Asteroseismic studies imply that overshoot is a weak mixing process. Diffusion model is suitable to deal ... More
The solar abundance problem: the effect of the turbulent kinetic flux on the solar envelope modelApr 19 2014Recent 3D-simulations have shown that the turbulent kinetic flux (TKF) is significant. We discuss the effects of TKF on the size of convection zone and find that the TKF may help to solve the solar abundance problem. The solar abundance problem is that, ... More
Local estimates on two linear parabolic equations with singular coefficientsMay 30 2019We treat the heat equation with singular drift terms and its generalization: the linearized Navier-Stokes system. In the first case, we obtain boundedness of weak solutions for highly singular, "supercritical" data. In the second case, we obtain regularity ... More
Extremal of Log Sobolev inequality and $W$ entropy on noncompact manifoldsMay 08 2011Let $\M$ be a complete, connected noncompact manifold with bounded geometry. Under a condition near infinity, we prove that the Log Sobolev functional (\ref{logfanhan}) has an extremal function decaying exponentially near infinity. We also prove that ... More
LS 5039 - the counterpart of the unidentified MeV source GRO J1823-12Feb 11 2014The COMPTEL experiment on CGRO observed the gamma-ray sky at energies from 0.75 MeV to 30 MeV between April 1991 and June 2000. COMPTEL detected many gamma-ray sources, among them an unidentified one labeled GRO J1823-12, which is positionally consistent ... More
No breathers theorem for some noncompact Ricci flowsMay 02 2012Aug 16 2013Under suitable conditions near infinity and assuming boundedness of curvature tensor, we prove a no breathers theorem in the spirit of Ivey-Perelman for some noncompact Ricci flows. These include Ricci flows on asymptotically flat (AF) manifolds with ... More
Testing the core overshooting mixing described by the turbulent convection model on the eclipsing binary star HY VirNov 01 2012Helioseismic investigation has suggested to apply the turbulent convection models (TCMs) to the convective overshooting. Using the turbulent velocity in the overshooting region determined by the TCM, one can deal with the overshooting mixing as a diffusion ... More
Numerical integral of resistance coefficients in diffusionNov 09 2016The resistance coefficients in screen Coulomb potential of stellar plasma are evaluated in high accuracy. I have analyzed the possible singularities in the integral of scattering angle. There are possible singularities in the case of attractive potential. ... More
The YNEV stellar evolution and oscillation codeJun 26 2014Jun 27 2014We have developed a new stellar evolution and oscillation code YNEV, which calculates the structures and evolutions of stars, taking into account hydrogen and helium burning. A nonlocal turbulent convection theory and an updated overshoot mixing model ... More
A note on time analyticity for ancient solutions of the heat equationMay 14 2019It is well known that generic solutions of the heat equation are not analytic in time in general. Here it is proven that ancient solutions with exponential growth are analytic in time in ${\M} \times (-\infty, 0]$. Here $\M=\R^n$ or is a manifold with ... More
A uniform Sobolev inequality under Ricci flowJun 12 2007Aug 29 2007Let ${\bf M}$ be a compact Riemannian manifold and the metrics $g=g(t)$ evolve by the Ricci flow. We prove the following result. The Sobolev imbedding by Aubin or Hebey, perturbed by a scalar curvature term and modulo sharpness of constants, holds uniformly ... More
Flow Study in Relativistic Nuclear Collisions by Fourier Expansion of Azimuthal Particle DistributionsJul 12 1994We propose a new method to study transverse flow effects in relativistic nuclear collisions by Fourier analysis of the azimuthal distribution on an event-by-event basis in relatively narrow rapidity windows. The distributions of Fourier coefficients provide ... More
The diffusive overshooting approach on Li abundance in clustersSep 05 2012The helioseimic investigation shows that the convective overshooting can penetrate $0.37H_P$ to the location where the temperature is $2.5\times10^6 K$ which is the typical temperature of the reaction $Li^7(p,\alpha)He^4$. This indicates that the overshooting ... More
Strong non-collapsing and uniform Sobolev inequalities for Ricci flow with surgeriesDec 09 2007We prove a uniform Sobolev inequality for Ricci flow, which is independent of the number of surgeries. As an application, under less assumptions, a non-collapsing result stronger than Perelman's $\kappa$ non-collapsing with surgery is derived. The proof ... More
Heat kernel bounds, ancient $κ$ solutions and the Poincaré conjectureDec 12 2008Feb 21 2009We establish certain Gaussian type upper bound for the heat kernel of the conjugate heat equation associated with 3 dimensional ancient $\kappa$ solutions to the Ricci flow. As an application, using the $W$ entropy associated with the heat kernel, we ... More
Experimental study for leptonic and semileptonic decays in the charm sectorJun 21 2019Leptonic and semileptonic decays in the charm sector have been well studied in recent years. With the largest data sample near $D\bar D$ threshold, precision measurements of leptonic and semileptonic decays of charm meson and baryon are perfromed at BESIII. ... More
On the question of diameter bounds in Ricci flowJul 10 2013Sep 10 2013A question about Ricci flow is when the diameters of the manifold under the evolving metrics stay finite and bounded away from 0. Topping \cite{T:1} addresses the question with an upper bound that depends on the $L^{(n-1)/2}$ bound of the scalar curvature, ... More
Minimizers of the sharp Log entropy on manifolds with non-negative Ricci curvature and flatnessAug 03 2017Consider the scaling invariant, sharp log entropy (functional) introduced by Weissler \cite{W:1} on noncompact manifolds with nonnegative Ricci curvature. It can also be regarded as a sharpened version of Perelman's W entropy \cite{P:1} in the stationary ... More
A critical regularity condition on the angular velocity of axially symmetric Navier-Stokes equationsMay 04 2015Let $v$ be the velocity of Leray-Hopf solutions to the axially symmetric three-dimensional Navier-Stokes equations. It is shown that $v$ is regular if the angular velocity $v_\theta$ satisfies an integral condition which is critical under the standard ... More
Some gradient estimates for the heat equation on domains and for an equation by PerelmanMay 18 2006Oct 11 2006In the first part, we derive a sharp gradient estimate for the log of Dirichlet heat kernel and Poisson heat kernel on domains, and a sharpened local Li-Yau gradient estimate that matches the global one. In the second part, without explicit curvature ... More
Confidence Intervals for Low-Dimensional Parameters in High-Dimensional Linear ModelsOct 12 2011Nov 02 2012The purpose of this paper is to propose methodologies for statistical inference of low-dimensional parameters with high-dimensional data. We focus on constructing confidence intervals for individual coefficients and linear combinations of several of them ... More
Spectral State Transitions in Aql X-1: Evidence for `Propeller' EffectsNov 24 1997Aql X-1 is a soft X-ray transient source and emits type I X-ray bursts. A spectral state transition was observed with RXTE during its outburst decay in February and March 1997. Its 10-30 keV and 5-10 keV count rate ratio increased suddenly when its luminosity ... More
Dynamical spin correlations in Heisenberg ladder under magnetic field and correlation functions in SO(5) ladderJul 28 1998Apr 14 1999The zero-temperature dynamical spin-spin correlation functions are calculated for the spin-1/2 two-leg Heisenberg ladder in a magnetic field above the lower critical field Hc1. The dynamical structure factors are calculated which exhibit both massless ... More
Turbulent convection model in the overshooting region: II. Theoretical analysisFeb 20 2012Feb 21 2012Turbulent convection models are thought to be good tools to deal with the convective overshooting in the stellar interior. However, they are too complex to be applied in calculations of stellar structure and evolution. In order to understand the physical ... More
Formation and Disruption of Globular Star ClustersSep 18 2001In the first part of this article, we review observations of the mass and luminosity functions of young and old star cluster systems. We also review some of the physical processes that may determine the characteristic mass of globular clusters and the ... More
On ancient periodic solutions to Axially-Symmetric Navier-Stokes EquationsFeb 28 2019An old problem asks whether bounded mild ancient solutions of the 3 dimensional Navier-Stokes equations are constants. While the full 3 dimensional problem seems out of reach, in the works \cite{KNSS, SS09}, the authors expressed their belief that the ... More
Comment: The Essential Role of Pair Matching in Cluster-Randomized Experiments, with Application to the Mexican Universal Health Insurance EvaluationOct 20 2009Comment on ``The Essential Role of Pair Matching in Cluster-Randomized Experiments, with Application to the Mexican Universal Health Insurance Evaluation'' [arXiv:0910.3752]
Fermi surface of a trapped dipolar Fermi gasJul 16 2009Nov 18 2009Under the framework of the semiclassical theory, we investigate the equilibrium-state properties of a spin polarized dipolar Fermi gas through full numerical calculation. We show that the Fermi surfaces in both real and momentum spaces are stretched along ... More
Comment on "Effects of Thickness on the Spin Susceptibility of the Two Dimensional Electron Gas"Jul 05 2005Jul 23 2006A comment on a recent paper (PRL {\bf 94}, 226405 (2005)) by S. De Palo, M. Botti, S. Moroni, and Gaetano Senatore.
Mutual Community Detection across Multiple Partially Aligned Social NetworksJun 18 2015Community detection in online social networks has been a hot research topic in recent years. Meanwhile, to enjoy more social network services, users nowadays are usually involved in multiple online social networks simultaneously, some of which can share ... More
Electron heating in the laser and static electric and magnetic fieldsNov 17 2017Jan 31 2018A 2D slab approximation of the interactions of electrons with intense linearly polarized laser radiation and static electric and magnetic fields is widely used for both numerical simulations and simplified semi-analytical models. It is shown that in this ... More
Joint latent class trees: A Tree-Based Approach to Joint Modeling of Time-to-event and Longitudinal DataDec 05 2018Jun 10 2019Joint modeling of longitudinal and time-to-event data provides insights into the association between the two quantities. The joint latent class modeling approach assumes that conditioning on latent class membership, the trajectories of longitudinal data ... More
An Upper Bound for Hessian Matrices of Positive Solutions of Heat EquationsDec 12 2012We prove global and local upper bounds for the Hessian of log positive solutions of the heat equation on a Riemannian manifold. The metric is either fixed or evolves under the Ricci flow. These upper bounds supplement the well-known global lower bound. ... More
Extended Lorentz cones and variational inequalities on cylindersMar 20 2015Solutions of a variational inequality are found by giving conditions for the monotone convergence with respect to a cone of the Picard iteration corresponding to its natural map. One of these conditions is the isotonicity of the projection onto the closed ... More
Sharp gradient estimate and Yau's Liouville theorem for the heat equation on noncompact manifoldsFeb 03 2005We derive a sharp, localized version of elliptic type gradient estimates for positive solutions (bounded or not) to the heat equation. These estimates are akin to the Cheng-Yau estimate for the Laplace equation and Hamilton's estimate for bounded solutions ... More
Analysis of chaotic flow in a 2D multi-turn closed-loop pulsating heat pipeApr 21 2016Numerical study has been conducted for the chaotic flow in a multi-turn closed-loop pulsating heat pipe (PHP). Heat flux and constant temperature boundary conditions have been applied for heating and cooling sections respectively. Water was used as working ... More
Dynamical Evolution of the Mass Function of Globular Star ClustersJul 17 2001Oct 05 2001We present a series of simple, largely analytical models to compute the effects of disruption on the mass function of star clusters. Our calculations include evaporation by two-body relaxation and gravitational shocks and mass loss by stellar evolution. ... More
Spin Orbit Magnetism and Unconventional SuperconductivityNov 07 2012We find an exotic spin excitation in a magnetically ordered system with spin orbit magnetism in 2D, where the order parameter has a net spin current and no net magnetization. Starting from a Fermi liquid theory, similar to that for a weak ferromagnet, ... More
Impact of Step Defects on Surface States of Topological InsulatorsOct 17 2011The eigenstates in the presence of a step defect (SD) along $x$ or y axis on the surface of topological insulators are exactly solved. It is shown that unlike the electronic states in conventional metals, the topological surface states across the SD can ... More
The Energy-dependent Checkerboard Patterns in Cuprate SuperconductorsApr 08 2003Motivated by the recent scanning tunneling microscopy (STM) experiments [J. E. Hoffman {\it et al.}, Science {\bf 297}, 1148 (2002); K. McElroy {\it et al.}, Nature (to be published)], we investigate the real space local density of states (LDOS) induced ... More
A Liouville Theorem for the Axially-symmetric Navier-Stokes EquationsNov 23 2010Nov 27 2010Let $v(x, t)= v^r e_r + v^\theta e_\theta + v^z e_z$ be a solution to the three-dimensional incompressible axially-symmetric Navier-Stokes equations. Denote by $b = v^r e_r + v^z e_z$ the radial-axial vector field. Under a general scaling invariant condition ... More
Open Problems in Understanding the Nuclear ChiralityFeb 04 2010Open problems in the interpretation of the observed pair of near degenerate $\Delta I = 1$ bands with the same parity as the chiral doublet bands are discussed. The ambiguities for the existing fingerprints of the chirality in atomic nuclei and problems ... More
Temperature and magnetization-dependent band-gap renormalization and optical many-body effects in diluted magnetic semiconductorsJan 18 2005Sep 14 2005We calculate the Coulomb interaction induced density, temperature and magnetization dependent many-body band-gap renormalization in a typical diluted magnetic semiconductor GaMnAs in the optimally-doped metallic regime as a function of carrier density ... More
Temperature dependent effective mass renormalization in a Coulomb Fermi liquidDec 23 2003We calculate numerically the quasiparticle effective mass (m*) renormalization as a function of temperature and electron density in two- and three-dimensional electron systems with long-range Coulomb interaction. In two dimensions, the leading temperature ... More
Quasiparticle effective mass divergence in two dimensional electron systemsDec 22 2003Dec 14 2004Within the infinite series of ring (or bubble) diagram approximation for the electronic self-energy as appropriate for the long-range Coulomb interaction, we calculate the density-dependent T=0 Fermi liquid quasiparticle effective mass renormalization ... More
deepCR: Cosmic Ray Rejection with Deep LearningJul 22 2019Cosmic ray (CR) identification and removal are critical components of imaging and spectroscopic reduction pipelines involving solid-state detectors. We present deepCR, a deep learning based framework for cosmic ray (CR) identification and subsequent image ... More
Isoperimetric inequality under Kähler Ricci flowMar 07 2012Jul 10 2013Let $({\M}, g(t))$ be a K\"ahler Ricci flow with positive first Chern class. We prove a uniform isoperimetric inequality for all time. In the process we also prove a Cheng-Yau type log gradient bound for positive harmonic functions on $({\M}, g(t))$, ... More
Relativistic Jets from Collapsars: Gamma-Ray BurstsSep 23 2002Growing observational evidence supports the proposition that gamma-ray bursts (GRBs) are powered by relativistic jets from massive helium stars whose cores have collapsed to black holes and an accretion disk (collapsars). We model the propagation of relativistic ... More
deepCR: Cosmic Ray Rejection with Deep LearningJul 22 2019Aug 29 2019Cosmic ray (CR) identification and replacement are critical components of imaging and spectroscopic reduction pipelines involving solid-state detectors. We present deepCR, a deep learning based framework for CR identification and subsequent image inpainting ... More
Li-Yau gradient bounds on compact manifolds under nearly optimal curvature conditionsNov 03 2015May 28 2018We prove Li-Yau type gradient bounds for the heat equation either on manifolds with fixed metric or under the Ricci flow. In the former case the curvature condition is $|Ric^-| \in L^p$ for some $p>n/2$, or $\sup_\M \int_\M |Ric^-|^2(y)d^{2-n}(x,y)dy<\infty$, ... More
Existence of a degenerate singularity in the high activation energy limit of a reaction-diffusion equationApr 08 2009We consider the singular perturbation problem $$ \Delta u_\epsilon=\beta_\epsilon(u_\epsilon), $$ where $\beta_\epsilon(s)=\frac{1}{\epsilon}\beta(\frac{s}{\epsilon})$, $\beta$ is a Lipschitz continuous function such that $\beta>0$ in $(0, 1)$, $\beta\equiv ... More
Li-Yau gradient bound for collapsing manifolds under integral curvature conditionJul 20 2016Let $(\M^n, g_{ij})$ be a complete Riemammnian manifold. For some constants $p,\ r>0$, define $\displaystyle k(p,r)=\sup_{x\in M}r^2\left(\oint_{B(x,r)}|Ric^-|^p dV\right)^{1/p}$, where $Ric^-$ denotes the negative part of the Ricci curvature tensor. ... More
Regularity of Weak Solutions of Elliptic and Parabolic Equations with Some Critical or Supercritical PotentialsJan 11 2016We prove H\"older continuity of weak solutions of the uniformly elliptic and parabolic equations %$\Delta u-\frac{A}{|x|^{2+\beta}}u=0,\,\,(\beta\geq 0)$, and variable second order term coefficients case $%% \begin{equation}\label{01} \partial_{i} (a_{ij}(x) ... More
Uniqueness and traveling waves in a cell motility modelMar 02 2017We study a non-linear and non-local evolution equation for curves obtained as the sharp interface limit of a phase-field model for crawling motion of eukaryotic cells on a substrate. We establish uniqueness of solutions to the sharp interface limit equation ... More
Time analyticity for the heat equation and Navier-Stokes equationsJul 03 2019We prove the analyticity in time for non-decaying solutions of two parabolic equations in the whole space. One of them involves solutions to the heat equation of double exponential growth on $\M$. Here $\M$ is $\R^n$ or a complete noncompact manifold ... More
Li-Yau gradient bounds under nearly optimal curvature conditionsNov 03 2015Nov 10 2015We prove Li-Yau type gradient bounds for the heat equation either on manifolds with fixed metric or under the Ricci flow. In the former case the curvature condition is $|Ric^-| \in L^p$ for some $p>n/2$, or $\sup_\M \int_\M |Ric^-|^2(y)d^{2-n}(x,y)dy<\infty$, ... More
Joint latent class trees: A Tree-Based Approach to Joint Modeling of Time-to-event and Longitudinal DataDec 05 2018Joint modeling of longitudinal and time-to-event data provides insights into the association between the two quantities. The joint latent class modeling approach assumes that conditioning on latent class membership, the trajectories of longitudinal data ... More
Thermal Bremsstrahlung Radiation in a Two-Temperature PlasmaDec 07 2002Jan 08 2004In the normal one-temperature plasma the motion of ions is usually neglected when calculating the Bremsstrahlung radiation of the plasma. Here we calculate the Bremsstrahlung radiation of a two-temperature plasma by taking into account of the motion of ... More
Proposed Detection of Time Reversal Symmetry in Topological Surface StatesJan 18 2013By employing T-matrix approach, we investigate a nonmagnetic impurity located on the surface of three-dimensional topological insulators, where the time reversal symmetry is preserved. It is shown that the images of the local density of states (LDOS) ... More
Resonant Spin and Charge Hall Effects in 2D Electron Gas with Unequal Rashba and Dresselhaus Spin-Orbit Couplings under a Perpendicular Magnetic FieldOct 05 2015We have investigated the complex two-dimensional electron system with unequal Rashba and Dresselhaus spin-orbit interactions in the presence of a perpendicular magnetic field. The spin polarizations are obtained in a wide range of magnetic fields. It ... More
Energy-Dependent LDOS Modulation in Cuprate SuperconductorsSep 13 2002Sep 13 2002Motivated by the recent scanning tunneling microscopy (STM) experiment [J. E. Hoffman, {\it et al.}, Science {\bf 297}, 1148 (2002)], we investigate the energy-dependent modulation induced by a weak and extended defect in a d-wave superconductor. The ... More
Nonparametric inference of doubly stochastic Poisson process data via the kernel methodJan 06 2011Doubly stochastic Poisson processes, also known as the Cox processes, frequently occur in various scientific fields. In this article, motivated primarily by analyzing Cox process data in biophysics, we propose a nonparametric kernel-based inference method. ... More
Exchange instabilities in electron systems: Bloch versus Stoner FerromagnetismJan 10 2005Aug 26 2005We show that 2D and 3D electron systems with the long-range Coulomb electron-electron interaction could develop ferromagnetic instabilities due to strong exchange effects at low densities. The critical densities in both 2D and 3D systems at which the ... More
Criticality of the Axially Symmetric Navier-Stokes EquationsMay 11 2015May 28 2015Smooth solutions to the axi-symmetric Navier-Stokes equations obey the following maximum principle: $$\sup_{t\geq 0}\|rv^\theta(t, \cdot)\|_{L^\infty} \leq \|rv^\theta(0, \cdot)\|_{L^\infty}.$$ We prove that all solutions with initial data in $H^{\frac{1}{2}}$ ... More
On the distance control problem in Ricci flowsMar 08 2013Sep 02 2017We show that the distance function under the Ricci flow is uniformly continuous in the time direction, assuming only the scalar curvature is bounded.
Structure of Singularities of 3D Axi-symmetric Navier-Stokes EquationsAug 24 2010Let $v$ be a solution of the axially symmetric Navier-Stokes equation. We determine the structure of certain (possible) maximal singularity of $v$ in the following sense. Let $(x_0, t_0)$ be a point where the flow speed $Q_0 = |v(x_0, t_0)|$ is comparable ... More
Large time behavior of heat kernels on formsJun 13 2005We derive large time upper bounds for heat kernels on vector bundles of differential forms on a class of non-compact Riemannian manifolds under certain curvature conditions.
A gradient estimate for all positive solutions of the conjugate heat equation under Ricci flowNov 10 2006Nov 14 2006We establish a point-wise gradient estimate for $all$ positive solutions of the conjugate heat equation. This contrasts to Perelman's point-wise gradient estimate which works mainly for the fundamental solution rather than all solutions. Like Perelman's ... More
The Mass Function of Young Star Clusters in the "Antennae" GalaxiesNov 12 1999We determine the mass function of young star clusters in the merging galaxies the ``Antennae'' (NGC 4038/39) from deep images taken with the WFPC2 on the refurbished Hubble Space Telescope (HST). This is accomplished by means of reddening-free parameters ... More
The central nature of the Hidden Subgroup problemOct 13 2006Nov 17 2006We show that several problems that figure prominently in quantum computing, including Hidden Coset, Hidden Shift, and Orbit Coset, are equivalent or reducible to Hidden Subgroup for a large variety of groups. We also show that, over permutation groups, ... More
Models for Gamma-Ray Bursts and Diverse TransientsJan 11 2007The observational diversity of ``gamma-ray bursts'' (GRBs) has been increasing, and the natural inclination is a proliferation of models. We explore the possibility that at least part of this diversity is a consequence of a single basic model for the ... More
Comparison between Windowed FFT and Hilbert-Huang Transform for Analyzing Time Series with Poissonian Fluctuations: A Case StudySep 01 2006Hilbert-Huang Transform (HHT) is a novel data analysis technique for nonlinear and non-stationary data. We present a time-frequency analysis of both simulated light curves and an X-ray burst from the X-ray burster 4U 1702-429 with both the HHT and the ... More
Nonlinear 2D Spin Susceptibility in a Finite Magnetic Field: Spin-Polarization DependenceDec 19 2005Jun 01 2006By theoretically calculating the interacting spin susceptibility of a two-dimensional electron system in the presence of finite spin polarization, we show that the extensively employed technique of measuring the 2D spin susceptibility by linear extrapolation ... More
Spin Polarization Dependence of Carrier Effective Mass in Semiconductor Structures: Spintronic Effective MassSep 12 2005Dec 15 2005We introduce the concept of a spintronic effective mass for spin-polarized carriers in semiconductor structures, which arises from the strong spin-polarization dependence of the renormalized effective mass in an interacting spin-polarized electron system. ... More
Density dependent spin susceptibility and effective mass in interacting quasi-two dimensional electron systemsAug 14 2004Aug 29 2005Motivated by recent experimental reports, we carry out a Fermi liquid many-body calculation of the interaction induced renormalization of the spin susceptibility and effective mass in realistic two dimensional (2D) electron systems as a function of carrier ... More
Calibrating the updated overshoot mixing model on eclipsing binary stars: HY Vir, YZ Cas, X2 Hya & VV CrvApr 17 2014The detached eclipsing binary stars with convective cores provide a good tool to investigate the convective core overshoot. It has been performed on some binary stars to restrict the classical overshoot model which simply extends the boundary of fully ... More
A compactness result for Fano manifolds and Kähler Ricci flowsApr 15 2014We obtain a compactness result for Fano manifolds and K\"ahler Ricci flows. Comparing to the more general Riemannian versions by Anderson and Hamilton, in this Fano case, the curvature assumption is much weaker and is preserved by the K\"ahler Ricci flows. ... More
Positive operators of Extended Lorentz conesAug 26 2016Aug 29 2016In this paper necessary conditions and sufficient conditions are given for a linear operator to be a positive operators of an Extended Lorentz cone. Similarities and differences with the positive operators of Lorentz cones are investigated.
New Volume Comparison results and Applications to degeneration of Riemannian metricsMay 30 2016We consider a condition on the Ricci curvature involving vector fields, which is broader than the Bakry-\'Emery Ricci condition. Under this condition volume comparison, Laplacian comparison, isoperimetric inequality and gradient bounds are proven on the ... More
On ancient solutions of the heat equationDec 12 2017Aug 28 2018An explicit representation formula for all positive ancient solutions of the heat equation in the Euclidean case is found. In the Riemannian case with nonnegative Ricci curvature, a similar but less explicit formula is also found. Here it is proven that ... More
Nonlinear Analysis of Chaotic Flow in a Three-Dimensional Closed-Loop Pulsating Heat PipeJun 26 2016Aug 02 2016Numerical simulation has been conducted for the chaotic flow in a 3D closed-loop pulsating heat pipe (PHP). Heat flux and constant temperature boundary conditions were applied for evaporator and condenser sections, respectively. Water and ethanol were ... More
On the distance control problem in Ricci flowsMar 08 2013Apr 29 2013We show that the distance function under the Ricci flow is uniformly continuous in the time direction, assuming only the scalar curvature is bounded.
Application of the weak-measurement technique to study atom-vacuum interactionsOct 27 2014Oct 28 2015Quantum weak measurement has attracted much interest recently [J. Dressel et al., Rev. Mod. Phys. 86, 307 (2014)] because it could amplify some weak signals and provide a technique to observe nonclassical phenomena. Here, we apply this technique to study ... More
Model for Tunneling-mediated Impurity Resonances in Bilayer Cuprate SuperconductorsOct 11 2008We have studied tunneling-mediated local density of states (LDOS) of the surface layer of a bilayer cuprate, where a Zn impurity is located on the second Cu-O layer. When the tunneling strength between two Cu-O layers is larger than a critical value, ... More
The screening and ranking algorithm to detect DNA copy number variationsOct 01 2012DNA Copy number variation (CNV) has recently gained considerable interest as a source of genetic variation that likely influences phenotypic differences. Many statistical and computational methods have been proposed and applied to detect CNVs based on ... More
Thermodynamic properties of a dipolar Fermi gasJan 04 2010Mar 25 2010Based on the semi-classical theory, we investigate the thermodynamic properties of a dipolar Fermi gas. Through a self-consistent procedure, we numerically obtain the phase space distribution function at finite temperature. We show that the deformations ... More
Conic optimization and complementarity problemsJul 18 2016Although the Karush-Kuhn-Tucker conditions suggest a connection between a conic optimization problem and a complementarity problem, it is difficult to find an accessible explicit form of this relationship in the literature. This note will present such ... More
Extended Lorentz cones and mixed complementarity problemsMay 30 2014Dec 11 2014In this paper we extend the notion of a Lorentz cone. We call a closed convex set isotone projection set with respect to a pointed closed convex cone if the projection onto the set is isotone (i.e., monotone) with respect to the order defined by the cone. ... More
A Priori Bounds for the Vorticity of Axis Symmetric Solutions to the Navier-Stokes EquationsNov 11 2008Dec 02 2008We obtain a pointwise, a priori bound for the vorticity of axis symmetric solutions to the 3 dimensional Navier-Stokes equations. The bound is in the form of a reciprocal of a power of the distance to the axis of symmetry. This seems to be the first general ... More
The Conjugate Heat Equation and Ancient Solutions of the Ricci FlowJun 03 2010We prove Gaussian type bounds for the fundamental solution of the conjugate heat equation evolving under the Ricci flow. As a consequence, for dimension 4 and higher, we show that the backward limit of type I $\kappa$-solutions of the Ricci flow must ... More
Bounds on harmonic radius and limits of manifolds with bounded Bakry-Émery Ricci curvatureMay 29 2017Jul 04 2017Under the usual condition that the volume of a geodesic ball is close to the Euclidean one or the injectivity radii is bounded from below, we prove a lower bound of the $C^{\alpha} W^{1, q}$ harmonic radius for manifolds with bounded Bakry-\'Emery Ricci ... More
QSO-Galaxy Association and Gravitational LensingSep 01 2004Mar 11 2005The amplification caused by gravitational light bending by compact objects in a foreground galaxy can affect the apparent number density of background QSOs, as well as their distribution in the fields of galactic halos. In this work we investigate the ... More
Detecting super-Nyquist-frequency gravitational waves using a pulsar timing arrayApr 22 2016May 15 2016The maximum frequency of gravitational waves (GWs) detectable with traditional pulsar timing methods is set by the Nyquist frequency ($f_{\rm{Ny}}$) of the observation. Beyond this frequency, GWs leave no temporal-correlated signals; instead, they appear ... More