33,470 research outputs found
An Ultra-Low-Power Oscillator with Temperature and Process Compensation for UHF RFID Transponder
This paper presents a 1.28MHz ultra-low-power oscillator with temperature and process compensation. It is very suitable for clock generation circuits used in ultra-high-frequency (UHF) radio-frequency identification (RFID) transponders. Detailed analysis of the oscillator design, including process and temperature compensation techniques are discussed. The circuit is designed using TSMC 0.18μm standard CMOS process and simulated with Spectre. Simulation results show that, without post-fabrication calibration or off-chip components, less than ±3% frequency variation is obtained from –40 to 85°C in three different process corners. Monte Carlo simulations have also been performed, and demonstrate a 3σ deviation of about 6%. The power for the proposed circuitry is only 1.18µW at 27°C
High-Efficient Parallel CAVLC Encoders on Heterogeneous Multicore Architectures
This article presents two high-efficient parallel realizations of the context-based adaptive variable length coding (CAVLC) based on heterogeneous multicore processors. By optimizing the architecture of the CAVLC encoder, three kinds of dependences are eliminated or weaken, including the context-based data dependence, the memory accessing dependence and the control dependence. The CAVLC pipeline is divided into three stages: two scans, coding, and lag packing, and be implemented on two typical heterogeneous multicore architectures. One is a block-based SIMD parallel CAVLC encoder on multicore stream processor STORM. The other is a component-oriented SIMT parallel encoder on massively parallel architecture GPU. Both of them exploited rich data-level parallelism. Experiments results show that compared with the CPU version, more than 70 times of speedup can be obtained for STORM and over 50 times for GPU. The implementation of encoder on STORM can make a real-time processing for 1080p @30fps and GPU-based version can satisfy the requirements for 720p real-time encoding. The throughput of the presented CAVLC encoders is more than 10 times higher than that of published software encoders on DSP and multicore platforms
An asymmetrical synchrotron model for knots in the 3C 273 jet
To interpret the emission of knots in the 3C 273 jet from radio to X-rays, we
propose a synchrotron model in which, owing to the shock compression effect,
the injection spectra from a shock into the upstream and downstream emission
regions are asymmetric. Our model could well explain the spectral energy
distributions of knots in the 3C 273 jet, and predictions regarding the knots
spectra could be tested by future observations.Comment: 9 pages, 1 figure, 1 table, new version accepted for publication in
Ap
Weak coupling d-wave BCS superconductivity and unpaired electrons in overdoped La_{2-x}Sr_{x}CuO_{4} single crystals
The low-temperature specific heat (SH) of overdoped La_{2-x}Sr_{x}CuO_{4}
single crystals (0.178=<x=<0.290) has been measured. For the superconducting
samples (0.178=<x=<0.238), the derived gap values (without any adjusting
parameters) approach closely onto the theoretical prediction
\Delta_{0}=2.14k_{B}T_{c} for the weak-coupling d-wave BCS superconductivity.
In addition, the residual term \gamma(0) of SH at H=0 increases with x
dramatically when beyond x~0.22, and finally evolves into the value of a
complete normal metallic state at higher doping levels, indicating growing
amount of unpaired electrons. We argue that this large \gamma(0) cannot be
simply attributed to the pair breaking induced by the impurity scattering,
instead the phase separation is possible.Comment: 6 pages, 6 figures; Contents added; Accepted for publication in Phys.
Rev.
A scheme for demonstration of fractional statistics of anyons in an exactly solvable model
We propose a scheme to demonstrate fractional statistics of anyons in an
exactly solvable lattice model proposed by Kitaev that involves four-body
interactions. The required many-body ground state, as well as the anyon
excitations and their braiding operations, can be conveniently realized through
\textit{dynamic}laser manipulation of cold atoms in an optical lattice. Due to
the perfect localization of anyons in this model, we show that a quantum
circuit with only six qubits is enough for demonstration of the basic braiding
statistics of anyons. This opens up the immediate possibility of
proof-of-principle experiments with trapped ions, photons, or nuclear magnetic
resonance systems.Comment: 4 pages, 3 figure
Modeling of DBT Biodesulfurization by Resting Cells of Gordonia sp. WQ-01A Immobilized in Alginate Gel Beads in an Oil-water-immobilization System
In this study, the resting cells of Gordonia sp. WQ-01A, a DBT-desulfurizing strain, were immobilized by calcium alginate. Batch DBT biodesulfurization experiments using immobilized cells and n-dodecane as the oil phase were conducted in fermenter under
varying operating conditions such as initial DBT concentration, bead loading and the oil phase volume fraction. When the initial DBT concentration is 0.5, 1 and 5 mmol L-1, the DBT concentration dropped almost to zero after t = 40, 60 and 100 hours, respectively.
The influence of bead loading and the oil-phase volume fraction was small to the DBT biodesulfurization. Furthermore, a mathematical model was proposed to simulate the batch DBT biodesulfurization process in an oil-water-immobilization system, which took
into account the internal and external mass transfer resistances of DBT and oxygen, and the intrinsic kinetics of bacteria. To validate this model, the comparison between the model simulations and the experimental measurements of DBT concentration profiles in
the oil phase was carried out and the agreement is very good. In addition, the time and radius courses of DBT and oxygen concentrations within the alginate gel beads were reasonably
predicted by the proposed model
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