Journal of Jishou University(Natural Sciences Edition)

Design of Pixel Compensation Algorithm for Video Image Based on Local Convolution

ZHA Huaizhi

Journal of Jishou University(Natural Sciences Edition), 2023, 44(6): 1-8.

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A video image pixel compensation method based on local convolution (local convolution compensation) is proposed to repair missing pixels in high-speed moving targets.The method introduces local convolution to segment the neural network model and reconstruct video image frames.It activates the source video image and its corresponding pixel space,applies linear mean compensation to fill the interpolated frame holes in the video image,and evaluates the matching degree of the video image to complete the pixel compensation.Comparative experimental results show that the average gradient of the local convolution compensation method is 11.239,significantly higher than the other three comparative methods,which indicates that the video image after compensation using the local convolution method has higher clarity.

Community Detection Algorithm for Bipartite Networks Based on Spectral Clustering

LIU Chenchen, XU Ying

Journal of Jishou University(Natural Sciences Edition), 2023, 44(6): 9-13.

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In order to solve the problem of low precision and original network information lose in community detection of bipartite network,a new spectral clustering algorithm named SVD-MS is proposed.This method maps Barber's problem of maximizing the module size of bipartite networks to the problem of singular value vector decomposition,and combines heuristic algorithms to quickly solve vector partitioning problems.Experimental results show that,the SVD-MS algorithm can effectively partition the community structure of bipartite networks and preserve the original network information.

Spectrum Sensing Algorithm Based on Joint Detection of Skewness and Kurtosis

TAN Zhewen, LEI Kejun, YANG Xi, WANG Xuming, TAN Yuhao

Journal of Jishou University(Natural Sciences Edition), 2023, 44(6): 14-19.

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By normalizing the sample skewness and kurtosis of the received signal,a spectrum sensing algorithm based on joint detection of skewness and kurtosis (joint detection) is proposed.Utilizing the probability density function of the chi-square distribution,the theoretical false alarm performance of the algorithm is analyzed under non-asymptotic conditions,and the corresponding theoretical decision threshold is derived.In the simulation experiments,joint detection can still guarantee reliable detection results with small number of samples,and shows better detection performance than the classical Jarque-Bera (JB) spectrum sensing algorithm.

Harmonic and Inter-Harmonic Parameter Estimation Algorithm Based on MSLDSMC Window

CHEN Qianming, ZHANG Zhiwei, LI Minghao, WANG Xuming, LEI Kejun

Journal of Jishou University(Natural Sciences Edition), 2023, 44(6): 20-27.

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The fast Fourier transform (FFT) method may encounter spectral leakage and picket fence effect in harmonic detection,resulting in low accuracy in detecting harmonic and inter-harmonic parameters.To improve the detection accuracy,based on the maximum side lobe decay window (MSLD) with excellent sidelobe characteristics,we have constructe an MSLD self-multiplication-convolution window (MSLDSMC) by multiplication and convolution operations.On this basis we propos a high-precision estimation algorithm for harmonic and inter-harmonic parameters of three spectral line interpolation.Simulation experiments conducted in different complex scenarios verify the accuracy of harmonic and inter-harmonic parameter estimation algorithms based on MSLDSMC window three spectral line interpolation.

Acoustic Radiation Force of Microbubbles Within Microcavities

TIAN Zhen, KONG Peng, DENG Ke

Journal of Jishou University(Natural Sciences Edition), 2023, 44(6): 28-31.

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The trapping mechanism of microbubbles is analyzed based on microbubble acoustic radiation force theory and numerical simulation,and the acoustic radiation force of microbubbles in microcavities is studied.The theoretical analysis showed that when the driving frequency of the sound field is lower than the resonant frequency of the microbubble,the force direction of the microbubble points to the maximum value of the sound field.When the driving frequency of the sound field is higher than the resonant frequency of the microbubble,the force direction of the microbubble points to the minimum value of the sound field.Combined with finite element simulation of the quartz cavity,it is verified that the resonance properties exhibited by microbubbles of different sizes in the same acoustic field are different.Smaller microbubbles move towards the acoustic field minimum under the action of standing waves,while larger microbubbles move in the opposite direction.

Design of Ultrathin Transmissive Acoustic Cloak

SUI Yumei, KONG Peng, DENG Ke, ZHAO Heping

Journal of Jishou University(Natural Sciences Edition), 2023, 44(6): 32-36.

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Acoustically transmissive cloak is constructed with a combination of two labyrinthine type metasurfaces-phase-modulated metasurface and near-zero refractive index metasurface.The near-zero refractive index metasurface is verified by energy band calculation and equivalent medium theory to have zero refractive index property similar to phonon crystals,so that it can guide the acoustic waves to continue to go around the obstacles in the original direction of the acoustic waves;the phase-modulated metasurface,on the other hand,should have a high transmittance while having the role of phase-modulation to ensure that the acoustic waves can pass through in large quantities.The simulations and calculations show that the acoustic transmission cloak formed by the construction works well.

Tunable Dual-Frequency Perfect Absorber with Graphene

ZHAO Jinyun, SHAN Xinyu, GAO Guangbo, HUANG Yonggang

Journal of Jishou University(Natural Sciences Edition), 2023, 44(6): 37-43.

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A tunable dual-frequency perfect absorber consisting of a graphene resonator,a SiO₂dielectric layer and a metal reflector layer has been designed by utilizing the excellent tunable optical properties of graphene.The effects of graphene chemical potential,polarization angle and size on the absorber absorption performance were systematically investigated,and the electric field pattern at the resonance frequency was analyzed to further explain the principle of absorber absorption.The results show that the absorber has an absorption rate of 99.98% and 99.99% at 6.363 and 8.987,respectively.The absorption peak position of the absorber can be effectively adjusted by changing the chemical potential of graphene,and the peak absorption rate can reach more than the peak absorption rate at any polarization angle in the range of 0°~80°.The thickness of the SiO₂ dielectric layer has almost no effect on the resonance peak position of this absorber,but it has some effect on the peak absorption rate,which increases and then decreases with the gradual increase of the thickness,and perfect absorption is achieved near the thickness of 3.1 μm.The high absorption rate of this absorber stems mainly from the electromagnetic resonance effect.

Entanglement Dynamics of Three-Level Atoms with Light Fields

QING Jiayang, WU Yunwen

Journal of Jishou University(Natural Sciences Edition), 2023, 44(6): 44-49.

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The system of three-level atom interacting with light field is studied by using the method of full quantum theory.Based on wave function,the dynamic evolution characteristics of different quantum states with the same coupling intensity are studied.In addition,the influence of different coupling intensity of the same quantum state on the dynamic evolution characteristics of the system is discussed.The results show that under the same coupling intensity,the population values of atoms in |b₁> states first decrease and then increase with time,the population values of atoms in |b₂> states and |b₃> states first increase and then decrease with time,and the corresponding population values of |b₂> states produce three peaks in the same period.The population values corresponding to the |b₃> states produce two peaks in the same period,and there is also a trough after the first peak,and the population values of different quantum states show periodic oscillations with time.In the same quantum state,with the increase of the coupling coefficient,the dynamic evolution oscillation characteristics of the quantum state between the light field and atoms are enhanced,and the system dynamic evolution pattern always maintains periodic changes with the increase of time.

Spontaneous Radiation Dynamics of Three-Level Atoms Near Silver Nanospheres

LI Yun, GAO Guangbo, SHAN Xinyu, HUANG Yonggang

Journal of Jishou University(Natural Sciences Edition), 2023, 44(6): 50-58.

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Based on the method of Green's function presolvation operator,the spontaneous radiation dynamics of V-type three-level atoms near silver nanospheres are studied.The effects of atomic transition frequency and atomic distance on the surface of the nanosphere on the spontaneous radiation dynamics are investigated systematically.The results show that when the transition frequency of the atom is far away from the resonant frequency of the isoplasmon,the evolution spectrum of the atom is half high and narrow,the dynamic oscillation is enhanced,and the decay rate is slow with time.When the two transition frequencies are close to the formant frequency,the kinetic oscillation of the atom is weakened,and the attenuation rate is faster with time.The distance between the atom and the surface of the nanosphere plays an important role in the coherent oscillation.The closer the distance,the stronger the coherent oscillation;and the farther the distance,the weaker the coherent oscillation.

Resonant Casimir-Polder Force Properties of Atoms in the Vicinity of a Convex Structure

GAO Guangbo, SHAN Xinyu, ZHAO Jinyun, HUANG Yonggang

Journal of Jishou University(Natural Sciences Edition), 2023, 44(6): 59-66.

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The influence of the transition frequency and position of a two-level atom in the vicinity the convex structure on the resonant casimir-polder force is studied by using COMSOL Multiphysics software.The results show that compared with the cross-sectional silver nanospheres,the convex structure produces a new surface plasmon resonance mode,which greatly enhances the resonance casimir-polder force on the atom.In addition,when the atom is close to the surface of the convex structure,the new resonance mode plays a leading role in the regulation of the resonant casimir-polder force,and the contribution of the new resonant mode to the resonant casimir-polder force decreases sharply with the increase of the distance.and the contribution of the resonance mode produced by the bulge is faster than that produced by the cross-section silver nanospheres.

Spontaneous Emission of Atoms in Double-Column Structure Based on Quasi-Normal Mode Theory

CHEN Xuanren, SHAN Xinyu, YANG Hong

Journal of Jishou University(Natural Sciences Edition), 2023, 44(6): 67-74.

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Based on the quasi-normal mode (QNM) theory,in the local photoresponse model,fluid dynamics model and generalized non-local photoresponse model of free electrons in metals,the spontaneous emission enhancement characteristics of two-level atoms in the nano-column structure are studied.With efficient coupled QNM theory,the effects of quantum dot position and double-column gap distance on the enhancement properties of spontaneous emission are investigated.The results show that compared with the full-wave method,the quasi-canonical mode method can efficiently and accurately calculate the enhanced characteristics of spontaneous emission,and the nanopillar gap has an important influence on the resonance frequency of the quasi-canonical mode.These studies have important guiding significance for understanding the nanoscale dimer structure to enhance light-matter interaction.

Effect of Metal Doping on the Rectification Characteristics of CdTe Nanodevices

YANG Jinbiao, LIAO Wenhu, BAO Hairui

Journal of Jishou University(Natural Sciences Edition), 2023, 44(6): 75-79.

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Based on density functional theory combined with non-equilibrium Green's function,the voltammetric properties of transition metal Cu-Cr,Cu-V and Cu-Ti co-doped CdTe nanoelectronic devices were systematically investigated.The results show that the voltammetric curves of the three different co-doped CdTe nanodevices exhibit diode voltammetric curves and produce strong rectification effects in the bias voltage range of [+0.4 V,+0.8 V].The highest rectification ratios are 5.4×10⁴,3.8×10⁵,and 2.1×10⁶,respectively.The projected density of states further confirms the high rectification ratio of the device at +1.0 V bias.Under the Cu-Cr co-doping condition,the device current decreases somewhat at +0.9 V bias with increasing channel length in the center region,but the overall rectification performance is significantly improved in the [+0.5 V,+0.7 V] bias range.

Manipulation of the Band Structure of Weyl Semimetals by Electric and Magnetic Fields

LUO Shuzhen, LIAO Wenhu, BAO Hairui

Journal of Jishou University(Natural Sciences Edition), 2023, 44(6): 80-89.

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Based on the low-energy effective hamiltonian model under the tight-binding approximation,the modulation of the electronic band structure of weyl semimetals by applied electric and/or magnetic fields is investigated.The results show that:when only the positive (negative) electric field is applied,the weyl points of system gradually move towards the boundary (center) of the brillouin zone with the increasing of the electric field strength,and when the electric field strength increases to a certain extent,the semimetal-semiconductor (insulator) transition can be relieazed;when only the magnetic field is applied,the weyl semimetal can form the discrete landau levels,the n=0 subband does not change with the increasing of magnetic length while the n≠0 subband gradually approaches the fermi level with the increasing of magnetic length,and the band gap between the conduction and valence bands with same indices gradually decrease;when the magnetic length remains unchanged,the weyl points of system gradually move towards the boundary (center) of the brillouin zone with the increasing of the positive (negative) electric field strength.Under the appropriate electric field,the n=0 subband can change from partially occupied valence band to first conduction band (fully occupied first valence band) and realize the semimetal-semiconductor or semimetal-insulator transitions.

Energy Functional of Orbital-Free Density Functional Theory for Sodium Metal Slab

LIU Runfeng, HU Qihong, ZHOU Fang, CHENG Xiaodi, WANG Xiaoyun, HUANG Yonggang

Journal of Jishou University(Natural Sciences Edition), 2023, 44(6): 90-96.

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The method of using OF-DFT to study the ground-state density and work function of metal sodium plates was explored.Through extensive numerical experiments,it was determined that a vW kinetic energy functional weight of 0.4 is required to obtain accurate ground-state properties for metal sodium plates,and this kinetic energy functional weight is applicable to different exchange-correlation potentials.

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