Yang Y.,Anyang University, China |
Yang Y.,Joint Center for Particle
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2015
Dark matter (DM) annihilation or decay can affect the anisotropy of the cosmic microwave background (CMB). Therefore, the CMB data can be used to constrain the properties of a dark matter particle. In this work, we use the new CMB data obtained by the Planck satellite to investigate the limits on the basic parameters of a dark matter particle. The parameters are the dark matter mass (mχ) and the thermally averaged cross section (σv) for dark matter annihilation and the decay rate (Γ) (or lifetime τ=1/Γ) for dark matter decay. For dark matter annihilation, we also consider the impact of the structure formation process which is neglected by the recent work. We find that for DM annihilation, the constraints on the parameters are fann= σv/mχ<0.16×10-26cm3s-1GeV-1(or fann<0.89×10-6m3s-1kg-1, 95% C.L.). For DM decay, the constraints on the decay rate are Γ<0.28×10-25s-1(95% C.L.). © 2015 American Physical Society.
Wang N.,Guangxi Normal University |
Tian J.,Anyang University, China |
Scheid W.,Justus Liebig University
Physical Review C - Nuclear Physics | Year: 2011
The fusion probability in "hot" fusion reactions leading to the synthesis of superheavy nuclei is investigated systematically. The quasifission barrier influences the formation of the superheavy nucleus around the "island of stability" in addition to the shell correction. Based on the quasifission barrier height obtained with the Skyrme energy-density functional, we propose an analytical expression for the description of the fusion probability, with which the measured evaporation residual cross sections can be reproduced acceptably well. Simultaneously, some special fusion reactions for synthesizing new elements 119 and 120 are studied. The predicted evaporation residual cross sections for 50Ti+249Bk are ∼10-150 fb at energies around the entrance-channel Coulomb barrier. For the fusion reactions synthesizing element 120 with projectiles 54Cr and 58Fe, the cross sections fall to a few femtobarns, which seems beyond the limit of the available facilities. © 2011 American Physical Society.
Cui R.,Northwestern Polytechnical University |
Gao B.,Northwestern Polytechnical University |
Guo J.,Anyang University, China
Autonomous Robots | Year: 2012
This paper investigates the coordination of multiple robots with pre-specified paths, considering motion safety and minimizing the traveling time. A method to estimate possible collision point along the local paths of the robots is proposed. The repulsive potential energy is computed based on the distances between the robots and the potential collision points. This repulsive potential energy is used as the cost map of the probabilistic roadmap (PRM), which is constructed in the coordination space for multiple robots taking into account both motion time cost and safety cost. We propose a search method on the PRM to obtain the Pareto-optimal coordination solution for multiple robots. Both simulation and experimental results are presented to demonstrate the effectiveness of the algorithms. © 2011 Springer-Verlag.
Wang C.M.,Anyang University, China |
Yu F.J.,Anyang University, China
Physical Review B - Condensed Matter and Materials Physics | Year: 2011
We investigate the charge conductivity and current-induced spin polarization of the surface state of a three-dimensional topological insulator by including the hexagonal-warping effect of the Fermi surface in both the classical and quantum diffusion regimes. We present general expressions of conductivity and spin polarization, which are reduced to simple forms for the usual scattering potential. Due to the hexagonal warping, the conductivity and spin polarization show an additional quadratic carrier-density dependence both for the Boltzmann contribution and the quantum correction. In the presence of the warping term, the surface states still reveal weak antilocalization. Moreover, the dielectric function in the random phase approximation is also explored, and we find that it may be momentum-angle-dependent. © 2011 American Physical Society.
Xia N.,Anyang University, China |
Zhang L.,Anyang University, China
Materials | Year: 2014
MicroRNAs (miRNAs) play important functions in post-transcriptional regulation of gene expression. They have been regarded as reliable molecular biomarkers for many diseases including cancer. However, the content of miRNAs in cells can be low down to a few molecules per cell. Thus, highly sensitive analytical methods for miRNAs detection are desired. Recently, electrochemical biosensors have held great promise as devices suitable for point-of-care diagnostics and multiplexed platforms for fast, simple and low-cost nucleic acid analysis. Signal amplification by nanomaterials is one of the most popular strategies for developing ultrasensitive assay methods. This review surveys the latest achievements in the use of nanomaterials to detect miRNAs with a focus on electrochemical techniques. © 2014 by the authors; licensee MDPI, Basel, Switzerland.