1,121 research outputs found
Kondo Signatures of a Quantum Magnetic Impurity in Topological Superconductors
We study the Kondo physics of a quantum magnetic impurity in two-dimensional topological superconductors (TSCs), either intrinsic or induced on the surface of a bulk topological insulator, using a numerical renormalization group technique. We show that, despite sharing the p+ip pairing symmetry, intrinsic and extrinsic TSCs host different physical processes that produce distinct Kondo signatures. Extrinsic TSCs harbor an unusual screening mechanism involving both electron and orbital degrees of freedom that produces rich and prominent Kondo phenomena, especially an intriguing pseudospin Kondo singlet state in the superconducting gap and a spatially anisotropic spin correlation. In sharp contrast, intrinsic TSCs support a robust impurity spin doublet ground state and an isotropic spin correlation. These findings advance fundamental knowledge of novel Kondo phenomena in TSCs and suggest experimental avenues for their detection and distinction
Novel path curvature optimization algorithm for intelligent wheelchair to smoothly pass a narrow space
This paper presents a novel algorithm to address the smooth narrow pass traversing issue, which is based on optimizing the curvature of the wheelchair path. Being aware of the fact that the path smoothness is determined by the path curvature and its change rate, after calculating the position of the narrow pass relative to the base frame of the wheelchair from perception sensor data, the algorithm takes the curvature and its change rate of Bezier curve as the optimal objective, and the wheelchair heading and the condition that the Bezier curve polygon should be convex polygon as constraints, and plans a smooth and optimal path for the controlled wheelchair to follow. This process is iterated dynamically to enable the intelligent wheelchair to traverse the narrow pass smoothly. Simulation is firstly conducted to compare the performances of our method and the A*-based path planning navigation algorithm, which shows that the proposed algorithm is able to achieve more smooth path with smaller curvature when the wheelchair traverses narrow path. Furthermore, the algorithm can control the wheelchair to traverse narrow pass smoothly even without any global map and localization. Real experiment with detailed explanation of algorithm implementation is also given to verify the effectiveness of the proposed algorithm
Design of Filtering Crossover Based on 180° Filtering Couplers
This article presents a novel crossover with an embedded bandpass filter function. The crossover is derived from the traditional crossover based on a tandem connection of two 3-dB 90° couplers by substituting them with 180° filtering couplers and introducing a filter function. In addition, a 180° phase shift realized by coupled resonators is added to keep the two cross paths in phase. The equivalent circuit of the crossover between the two diagonal ports has been treated as bandpass filters with coupled resonators. The design equations are derived to assist with the synthesis process for the filtering crossover. For verification, a filtering crossover with fifth-order filter characteristics, operating at 2.4 GHz, is designed, fabricated, and tested. The measured results match very well with the simulation, which verifies the proposed circuit concept.</p
Experimental and analytical analysis of polarization and water transport behaviors of hydrogen alkaline membrane fuel cell
Experimental test and analytical modeling are conducted to investigate the operating behavior of an alkaline electrolyte membrane (AEM) fuel cell fed by H2/air (or O2) and explore the effect of various operating pressures on the water transfer mechanism. According to the experimental test, the cell performance is greatly improved through increasing the operating pressure gradient from anode to cathode which leads to significant liquid water permeation through the membrane. The high frequency resistance of the A901 alkaline membrane is observed to be relatively stable as the operating pressure varies based on the electrochemical impedance spectroscopy (EIS) method. Correspondingly, based on the modeling prediction, the averaged water content in the membrane electrode assembly (MEA) does not change too much which leads to the weak variation of membrane ohmic resistance. This reveals that the performance enhancement should give the credit to better electro-chemical reaction kinetics for both the anode and cathode, also prone by the EIS results. The reversion of water back diffusion direction across the membrane is also observed through analytical solution
Soliton Solutions on Noncommutative Orbifold $ T^2/Z_4
In this paper, we explicitly construct a series of projectors on integral
noncommutative orbifold by extended constrution. They include
integration of two arbitary functions with symmetry. Our expressions
possess manifest symmetry. It is proved that the expression include all
projectors with minimal trace and in their standard expansions, the eigen value
functions of coefficient operators are continuous with respect to the arguments
and . Based on the integral expression, we alternately show the
derivative expression in terms of the similar kernal to the integral one.Since
projectors correspond to soliton solutions of the field theory on the
noncommutative orbifold, we thus present a series of corresponding solitons.Comment: 18 pages, no figure; referrences adde
Online quality control of panaxatriol saponins percolation extraction using near-infrared technology
Purpose: To establish a new prediction model for online quality control of the percolation extraction of panaxatriol saponins (PTS), viz, ginsenoside Rg1, ginsenoside Re and notoginsenoside R1, from notoginseng by near-infrared (NIR) technology coupled with partial least squares (PLS) analysis.Methods: Ten batches of PTS (420 samples) were collected and the constituents were determined using HPLC. The NIR spectroscopy of samples was determined using a Fourier-Transform nearinfrared spectrometer with an optical fiber transmission PbS detector. Eight sample batches were the calibration set, and two batches were the forecast set. Calibration models were established based on min-max normalization (MMN).Results: The root mean square errors of cross-validation (RMSECV) of Rg1, Re, and R1 were 0.798, 0.095, and 0.259 mg/mL, respectively. The root mean square errors of prediction (RMSEP) were 1.110, 0.496, and 0.390 mg/mL, respectively. The correlation coefficients (R2) of cross-validation were 0.9682, 0.9681, and 0.9626, respectively, while the correlation coefficients (R2) of prediction were 0.9831, 0.9198, and 0.9661, respectively.Conclusion: The results indicate that NIR is a quick and effective tool for online quality control of PTS (ginsenoside Rg1, ginsenoside Re, and notoginsenoside R1) in the percolation extraction process.Keywords: Online monitoring, Near infrared technology, Panaxatriol saponins, Partial least square
The RN/CFT Correspondence Revisited
We reconsidered the quantum gravity description of the near horizon extremal
Reissner-Nordstr{\o}m black hole in the viewpoint of the AdS/CFT
correspondence. We found that, for pure electric case, the right moving central
charge of dual 1D CFT is which is different from the previous result of left moving sector obtained by warped AdS/CFT description. We
discussed the discrepancy in these two approaches and examined novel properties
of our result.Comment: revtex4, 16 pages, sign mistakes corrected, references include
Superconductivity and Charge-density-wave-like Transition in Th2Cu4As5
We report the synthesis, crystal structure, and physical properties of a
novel ternary compound, ThCuAs. The material crystallizes in a
tetragonal structure with lattice parameters {\AA} and
{\AA}. Its structure can be described as an alternating stacking
of fluorite-type ThAs layers with antifluorite-type double-layered
CuAs slabs. The measurement of electrical resistivity, magnetic
susceptibility and specific heat reveals that ThCuAs undergoes bulk
superconducting transition at 4.2 K. Moreover, all these physical quantities
exhibit anomalies at 48 K, where the Hall coefficient change the sign. These
findings suggest a charge-density-wave-like (CDW) transition, making
ThCuAs a rare example for studying the interplay between CDW and
superconductivity.Comment: 11 pages, 6 figures, and 1 tabl
Soft magnetic properties of [Fe80Ni20-O/NiZn-ferrite]n multilayer thin films for high frequency application
Conference Name:2014 International Conference on Advanced Engineering Materials and Architecture Science, ICAEMAS 2014. Conference Address: Xi'an, Shaanxi, China. Time:January 4, 2014 - January 5, 2014.In this research, a series of [Fe80Ni20-O/NiZn-ferrite]n multilayer thin films with different insulation layer thickness were prepared by magnetron sputtering at room temperature. The high frequency soft magnetic properties of [Fe80Ni20-O/NiZn-ferrite]n multilayer thin films were investigated. It was found that the in-plane magnetic anisotropy field (Hk) and saturation magnetizations (4πMs) can be adjusted by changing the insulation layer thickness, and the optimal Hk and 4πMs can be obtained as the insulation layer thickness of 2.5 nm. The adjustment of insulation layer thickness is essential to obtain low coercivity (Hc) and high permeability (μ') of the multilayer thin films. The measured resistivity (ρ) of [Fe80Ni20-O/NiZn-ferrite]n multilayer thin films was increased from 211 to 448 μΩ·cm with increasing the insulation layer thickness. ? (2014) Trans Tech Publications, Switzerland
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