13,396 research outputs found
Determination of Density of Trap States at Y\u3csub\u3e2\u3c/sub\u3eO\u3csub\u3e3\u3c/sub\u3e-Stabilized ZrO\u3csub\u3e2\u3c/sub\u3e/Si Interface of Yba\u3csub\u3e2\u3c/sub\u3eCu\u3csub\u3e3\u3c/sub\u3eO\u3csub\u3e7-ÎŽ\u3c/sub\u3e/Y\u3csub\u3e2\u3c/sub\u3eO\u3csub\u3e3\u3c/sub\u3e-Stabilized ZrO\u3csub\u3e2\u3c/sub\u3e/Si Capacitors
Yba2Cu3O7-ÎŽ/yttriaâstabilized zirconia (YSZ)/silicon superconductorâinsulatorâsemiconductor capacitors are characterized with currentâvoltage and capacitanceâvoltage (CâV) measurements at different temperatures between 223 and 80 K. As a result of ââfreezingââ of mobile ions in YSZ, effects of trapped charge at the YSZ/Si interface dominate the device electrical properties at superconducting temperatures. Density of interface states and its temperature dependence are determined using a modified high frequency CâV method, in which the temperature dependences of band gap, Fermi level, and active dopant and intrinsic carrier concentrations are considered. At superconducting temperatures, e.g., 80 K, the interface state density within the band gap is reduced to lower than 1Ă1011 cmâ2âeV at midgap. The low interface state density at the YSZ/Si interface is important for acceptable performance and reliability devices made up of such capacitors
Radio-to-TeV Phase-resolved Emission from the Crab Pulsar: The Annular Gap Model
In the framework of the three-dimensional (3D) annular gap model with
reasonable parameters (the magnetic inclination angle \alpha = 45 deg and the
view angle \zeta = 63 deg), we first use the latest hight energy data to
self-consistently calculate radio, X-ray, gamma-ray and TeV (MAGIC and VERITAS)
light curves, phase-averaged spectrum and phase-resolved spectra for the Crab
pulsar. It is found that the acceleration electric field and potential in the
annular gap and core gap are huge enough in the several tens of neutron star
radii. The pulsed emission of radio, X-ray, gamma-ray and TeV are mainly
generated from the emission of primary particles or secondary particles with
different emission mechanisms in the nearly similar region of the annular gap
located in the only one magnetic pole, which leads to the nearly
"phase-aligned" multi-wavelength light curves. The emission of peak 1 (P1) and
peak 2 (P2) is originated from the annular gap region near the null charge
surface, while the emission of bridge is mainly originated from the core gap
region. The phase-averaged spectrum and phase-resolved spectra of the Crab
pulsar from soft X-ray to TeV band are produced by four components: synchrotron
radiation from CR-induced and ICS-induced pairs dominates the X-ray band to
soft gamma-ray band (100 eV to 10 MeV); curvature radiation and synchrotron
radiation from the primary particles mainly contribute to gamma-ray band (10
MeV to \sim 20 GeV); ICS from the pairs significantly contributes to the TeV
gamma-ray band (\sim 20 GeV to 400 GeV). The multi-wavelength pulsed emission
from the Crab pulsar has been well modeled with the annular gap and core gap
model. To distinguish our single magnetic pole model from two-pole models, the
convincing values of the magnetic inclination angle and the viewing angle will
play a key role.Comment: 12 pages, 7 figures, 3 tables; published in ApJ on March 12. Due to
the character limitation, the abstract here has been adopted a shortened
versio
Donor complex formation due to a high-dose Ge implant into Si
To investigate boron deactivation and/or donor complex formation due to a highâdose Ge and C implantation and the subsequent solid phase epitaxy, SiGe and SiGeC layers were fabricated and characterized. Crossâsectional transmission electron microscopy indicated that the SiGe layer with a peak Ge concentration of 5 at.â% was strained; whereas, for higher concentrations, stacking faults were observed from the surface to the projected range of the Ge as a result of strain relaxation. Photoluminescence (PL) results were found to be consistent with dopant deactivation due to Ge implantation and the subsequent solid phase epitaxial growth of the amorphous layer. Furthermore, for unstrained SiGe layers (Ge peak concentration â„7 at.â%), the PL results support our previously proposed donor complex formation. These findings were confirmed by spreading resistance profiling. A model for donor complex formation is proposed
On rank-critical matrix spaces
© 2017 Elsevier B.V. A matrix space of size mĂn is a linear subspace of the linear space of mĂn matrices over a field F. The rank of a matrix space is defined as the maximal rank over matrices in this space. A matrix space A is called rank-critical, if any matrix space which properly contains it has rank strictly greater than that of A. In this note, we first exhibit a necessary and sufficient condition for a matrix space A to be rank-critical, when F is large enough. This immediately implies the sufficient condition for a matrix space to be rank-critical by Draisma (2006) [5], albeit requiring the field to be slightly larger. We then study rank-critical spaces in the context of compression and primitive matrix spaces. We first show that every rank-critical matrix space can be decomposed into a rank-critical compression matrix space and a rank-critical primitive matrix space. We then prove, using our necessary and sufficient condition, that the block-diagonal direct sum of two rank-critical matrix spaces is rank-critical if and only if both matrix spaces are primitive, when the field is large enough
On controllability of neuronal networks with constraints on the average of control gains
Control gains play an important role in the control of a natural or a technical system since they reflect how much resource is required to optimize a certain control objective. This paper is concerned with the controllability of neuronal networks with constraints on the average value of the control gains injected in driver nodes, which are in accordance with engineering and biological backgrounds. In order to deal with the constraints on control gains, the controllability problem is transformed into a constrained optimization problem (COP). The introduction of the constraints on the control gains unavoidably leads to substantial difficulty in finding feasible as well as refining solutions. As such, a modified dynamic hybrid framework (MDyHF) is developed to solve this COP, based on an adaptive differential evolution and the concept of Pareto dominance. By comparing with statistical methods and several recently reported constrained optimization evolutionary algorithms (COEAs), we show that our proposed MDyHF is competitive and promising in studying the controllability of neuronal networks. Based on the MDyHF, we proceed to show the controlling regions under different levels of constraints. It is revealed that we should allocate the control gains economically when strong constraints are considered. In addition, it is found that as the constraints become more restrictive, the driver nodes are more likely to be selected from the nodes with a large degree. The results and methods presented in this paper will provide useful insights into developing new techniques to control a realistic complex network efficiently
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