1,153 research outputs found

    Phonon-assisted tunneling in asymmetric resonant tunneling structures

    Full text link
    Based on the dielectric continuum model, we calculated the phonon assisted tunneling (PAT) current of general double barrier resonant tunneling structures (DBRTSs) including both symmetric and antisymmetric ones. The results indicate that the four higher frequency interface phonon modes (especially the one which peaks at either interface of the emitter barrier) dominate the PAT processes, which increase the valley current and decrease the PVR of the DBRTSs. We show that an asymmetric structure can lead to improved performance.Comment: 1 paper and 5 figure

    Quantum and classical correlations in the one-dimensional XY model with Dzyaloshinskii-Moriya interaction

    Full text link
    We study the effect of Dzyaloshinskii-Moriya (DM) interaction on pairwise quantum discord, entanglement, and classical correlation in the anisotropic XY spin-half chain. Analytical expressions for both quantum and classical correlations are obtained from the spin-spin correlation functions. We show that these pairwise quantities exhibit various behaviors in relation to the relative strengths of the DM interaction, the anisotropy and the magnetic intensity. We observe non-analyticities of the derivatives of both quantum and classical correlations with respect to the magnetic intensity at the critical point, with consideration of the DM interaction.Comment: 18pages, 6figure

    Centrality dependence of pTp_{T} spectra for identified hadrons in Au+Au and Cu+Cu collisions at sNN=200\sqrt{s_{NN}}= 200 GeV

    Full text link
    The centrality dependence of transverse momentum spectra for identified hadrons at midrapidity in Au+Au collisions at sNN=200\sqrt{s_{NN}}= 200 GeV is systematically studied in a quark combination model. The pT\mathrm{{p}_{T}} spectra of π±\pi^{\pm}, K±K^{\pm}, p(pˉ)p(\bar{p}) and Λ(Λˉ)\Lambda(\bar{\Lambda}) in different centrality bins and the nuclear modification factors (RCPR_{CP}) for these hadrons are calculated. The centrality dependence of the average collective transverse velocity for the hot and dense quark matter is obtained in Au+Au collisions, and it is applied to a relative smaller Cu+Cu collision system. The centrality dependence of pT\mathrm{{p}_{T}} spectra and the RCPR_{CP} for π0\pi^{0}, Ks0K_{s}^{0} and Λ\Lambda in Cu+Cu collisions at sNN=200\sqrt{s_{NN}}= 200 GeV are well described. The results show that <β(r)><\beta (r)> is only a function of the number of participants NpartN_{part} and it is independent of the collision system.Comment: 7 pages, 6 figure

    Twofold Structured Features-Based Siamese Network for Infrared Target Tracking

    Full text link
    Nowadays, infrared target tracking has been a critical technology in the field of computer vision and has many applications, such as motion analysis, pedestrian surveillance, intelligent detection, and so forth. Unfortunately, due to the lack of color, texture and other detailed information, tracking drift often occurs when the tracker encounters infrared targets that vary in size or shape. To address this issue, we present a twofold structured features-based Siamese network for infrared target tracking. First of all, in order to improve the discriminative capacity for infrared targets, a novel feature fusion network is proposed to fuse both shallow spatial information and deep semantic information into the extracted features in a comprehensive manner. Then, a multi-template update module based on template update mechanism is designed to effectively deal with interferences from target appearance changes which are prone to cause early tracking failures. Finally, both qualitative and quantitative experiments are carried out on VOT-TIR 2016 dataset, which demonstrates that our method achieves the balance of promising tracking performance and real-time tracking speed against other out-of-the-art trackers.Comment: 13 pages,9 figures,references adde

    The LAMOST Complete Spectroscopic Survey of Pointing Area (LaCoSSPAr) in the Southern Galactic Cap I. The Spectroscopic Redshift Catalog

    Full text link
    We present a spectroscopic redshift catalog from the LAMOST Complete Spectroscopic Survey of Pointing Area (LaCoSSPAr) in the Southern Galactic Cap (SGC), which is designed to observe all sources (Galactic and extra-galactic) by using repeating observations with a limiting magnitude of r=18.1 magr=18.1~mag in two 20 deg220~deg^2 fields. The project is mainly focusing on the completeness of LAMOST ExtraGAlactic Surveys (LEGAS) in the SGC, the deficiencies of source selection methods and the basic performance parameters of LAMOST telescope. In both fields, more than 95% of galaxies have been observed. A post-processing has been applied to LAMOST 1D spectrum to remove the majority of remaining sky background residuals. More than 10,000 spectra have been visually inspected to measure the redshift by using combinations of different emission/absorption features with uncertainty of σz/(1+z)<0.001\sigma_{z}/(1+z)<0.001. In total, there are 1528 redshifts (623 absorption and 905 emission line galaxies) in Field A and 1570 redshifts (569 absorption and 1001 emission line galaxies) in Field B have been measured. The results show that it is possible to derive redshift from low SNR galaxies with our post-processing and visual inspection. Our analysis also indicates that up to 1/4 of the input targets for a typical extra-galactic spectroscopic survey might be unreliable. The multi-wavelength data analysis shows that the majority of mid-infrared-detected absorption (91.3%) and emission line galaxies (93.3%) can be well separated by an empirical criterion of W2−W3=2.4W2-W3=2.4. Meanwhile, a fainter sequence paralleled to the main population of galaxies has been witnessed both in MrM_r/W2−W3W2-W3 and M∗M_*/W2−W3W2-W3 diagrams, which could be the population of luminous dwarf galaxies but contaminated by the edge-on/highly inclined galaxies (∼30%\sim30\%).Comment: 19 pages, 14 figures, 2 MRT, accepted by ApJ

    Prostate deformation from inflatable rectal probe cover and dosimetric effects in prostate seed implant brachytherapy: Deformation on prostate permanent brachytherapy dosimetry

    Get PDF
    Prostate brachytherapy is an important treatment technique for patients with localized prostate cancer. An inflatable rectal ultrasound probe cover is frequently utilized during the procedure to adjust for unfavorable prostate position relative to the implant grid. However, the inflated cover causes prostate deformation, which is not accounted for during dosimetric planning. Most of the therapeutic dose is delivered after the procedure when the prostate and surrounding organs-at-risk are less deformed. The aim of this study is to quantify the potential dosimetry changes between the initial plan (prostate deformed) and the more realistic dosimetry when the prostate is less deformed without the cover
    • …
    corecore