bluuebunny/crossref_metadata_2025 huggingface dataset:
Crystal field energy-levels of Nd3+:Gd3Sc2Al3O12 and fitting
Authors: Guo Chang-Xin  , Tan Xiao-Liang  , Liu Wen-Peng  , Yin Shao-Tang  , Jiang Hai-He  , Xiao Jin  , Xia Shang-Da  , Zhang Qing-Li  , Zhou Wen-Long  ,   anhui Provincial key Laboratory of Optical Devices and Materials, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sceinces, Hefei 230031, China;,   anhui Provincial key Laboratory of Optical Devices and Materials, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sceinces, Hefei 230031, China, Physics Department, University of Science and Technology of China, Hefei 230026, China;,   Physics Department, University of Science and Technology of China, Hefei 230026, China
Published: December 2020

Nd3+ :GSAG, a laser crystal of 942 nm with good performance, was grown by Czochralski method successfully, and its transmission spectra at room temperature were studied. Sixty-eight crystal field splitting levels of Nd3+ with the maximum up to 29967 cm-1 were identified, to which the Hamiltonian parameters of free-ion and crystal field were fitted, and the root-mean-square deviation of energy level fitting is 16.7 cm-1, which indicated that the experimental and calculated energy levels are well consistent. The obtained Hamiltonian parameters can be used to calculate the wavefunctions of Nd3+ in GSAG, predict its energy level splitting, study the luminescent properties and so on.
Denedritic growth in forced flow using the phase-field simulation
Authors: Zhu Chang-Sheng  , Wang Jun-Wei  , Wang Zhi-Ping  , Feng Li  ,   (1)State Key Laboratory of Gansu Advanced Non-ferrous Metal Materials, Lanzhou University of Technology, Lanzhou 730050, China; (2)State Key Laboratory of Gansu Advanced Non-ferrous Metal Materials, Lanzhou University of Technology, Lanzhou 730050, China, CAD Center, Lanzhou University of Technology, Lanzhou 730050, China
Published: December 2020

The assymmetrical dendritic growth and the effect of flow velocity on the temperature distribution and laminar flow boundary layer of both facing-flow side and against-flow side has been investigated numerically based on the phase-field model which incorporates both fluid flow and thermal noise, as well as reasonably high efficiency 3DAADCR. The computed results indicate that, the forced flow causes the dissymmetry of the distribution of the temperature distribution and laminar flow boundary layer of both facing-flow side and against-flow side, leading to the different undercooling on either sides, as a result, the dendritic growth towards the flow and inclination relative to the dissipating heat direction appear. At the same time, the undercooling of facing-flow side is greater than that of against-flow side, which is helpful to accelerate dendritic growth rate and makes the sidebranching steady growth, accordingly, resulting in assymmetrical sidebranching growth. With the increase of flow velocity, the greater the inclination, and the more obvious the assymmetrical degree.
Multi-step prediction method for time series based on chaotic operator network
Authors: Xiu Chun-Bo  , Xu Meng  ,   School of Electrical Engineering and Automation, Tianjin Polytechnic University, Tianjin 300160, China
Published: December 2020

Combining the phase space reconstruction theory and the time series analysis theory, a prediction network applied to time series multi-step prediction is proposed. The network is constructed in the weight-sum form of some chaotic operators. Constant connections are adopted among the units. The control parameters of chaotic operators are adjusted by chaos optimization algorithm. The training samples, constructed by known time series data, are used in the training process only once, which makes the dynamic characteristics of the network change and tend to the predicted system with the lapse of time. The validity of the network can be proved by computing the Lyapunov exponent of prediction data. The multi-step predictions for engineering data are also realized by the method. Simulation results prove that the method could validly predict time series when the predictive step is not too long.
Theoretical study of nanoparticles in insulators fabricated by metal ion implantation
Authors: Zhang Da-Cheng  , Shen Yan-Yan  , Huang Yuan-Jie  , Wang Zhuo  , Liu Chang-Long  ,   (1)School of Science, Tianjin University, Tianjin 300072, China; (2)School of Science, Tianjin University, Tianjin 300072, China;Tianjin Key Laboratory of Low Dimension Materials Physics and Preparing Technology,Institute of Advanced Materials Physics Faculty of Science, Tianjin 300072,  China
Published: December 2020

In this paper, a theoretical method based on the discrete electronic states is proposed to calculate the Fermi-level of metal nanoparticles embedded in an insulator. According to the calculations, the structures of metal nanoparticle energy level are acquired. Meanwhile, the new formula for evaluating the size of metal nanoparticle by using the information about the surface plasmon resonance peak is also provided. Many known phenomena related to the metal nanoparticles can be explained by this theory. The calculation results on size of nanoparticle are found to be in good agreement with the AFM measurements for high dose Cu implanted Si3N4/Si samples.
Characteristics of absorption and attenuation of thunder propagating in atmosphere
Authors: Ouyang Yu-Hua  , Yuan Ping  , Zhang Jing-Chuan  ,   (1)College of Physics and Electronic Engineering, Northwest Normal University,Lanzhou 730070, China; (2)College of Physics and Electronic Engineering, Northwest Normal University,Lanzhou 730070, China;College of Mechanic and Electrical Engineering; University of Tarim, Alar 843300, China; (3)College of Physics and Electronic Engineering, Northwest Normal University,Lanzhou 730070, China;School of Mathematics Physics and Software Engineering, Lanzhou Jiaotong University, Lanzhou 730070,China
Published: December 2020

Using the thunder signals of a C-G lightning process recorded in the Qinghai region and the theory of signal processing, the frequency spectrum of thunder at observation point is obtained; Based on the propagation theory of acoustic waves, the absorption coefficients in air are calculated and their variations with environmental factors are analyzed. The results show that under a certain profpagation distance and environmental condition, the absorption coefficient increases with frequency increasing. The attenuation of signal below 100Hz is negligible under a certain propagation distance and environmental factors. The attenuations for high-frequency signals of more than 500 Hz are large, their absorption coefficients increase rapidly with the relative humidity inereasing and vary nor-monotonical with temperature. It is deduced that high frequency components of more than 500Hz should be contained in the thunder source.
Transmission line analogy model of left-handed metamaterials microstructure configuration
Authors: Shi Peng-Fei  , Tang Zhen-An  , Liu Shu-Tian  , Gao Ren-Jing  , Duan Yu-Ping  ,   (1)Faculty of Electronic Information and Electrical Engineering, Dalian University of Technology, Dalian 116024, China; (2)School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024, China; (3)State Key Laboratory of Structural Analysis for Industrial Equipment, Dalian University of Technology, Dalian 116024, China
Published: December 2020

In this paper, based on the equivalent transmission line model a method of designing left-handed metamaterials micro-structures is proposed, verified and analyzed. Firstly, according to the basic transmission line model with left and right-handed characteristics, we build a new left-handed model by analogy. Then according to the qualitative analysis of the corresponding relationship of each component in the transmission line network to the shape and size of continuous medium micro-structure configuration, the specific size of model is inferred, and thus a reasonable left-handed metamaterials micro-structure configuration and the corresponding transmission line model are established. We have conducted a series of tests including numerical simulation, which verifies that there does exist the left-handed characteristic in a certain frequency band. Finally based on the numerical simulation and experiment the effects each micro-structural parameter on left-handed frequency position and bandwidth are analyzed, and the size parameter that affects the left hand characteristic most seriously is determined.
Patch nearfield acoustic holography based on the distributed source boundary point method
Authors: Bi Chuan-Xing  , Yuan Yan  , He Chun-Dong  , Xu Liang  ,   Institute of Sound and Vibration Research, Hefei University of Technology, Hefei 230009, China
Published: December 2020

Patch nearfield acoustic holography based on the distributed source boundary point method (DSBPM) is proposed to reduce an error of the reconstructed result obtained from the pressure measured on a small aperture. The extrapolated data on a larger holographic surface is obtained through the measured data on the small holographic surface using the DSBPM, then the extrapolated data is used to reconstruct sound source. The simulation results and the experimental results show that the method can provide a good reconstructed result under the condition of the small holographic aperture.
Numerical simulation on the plasma field within discharge chamber of electron cyclotron resonance ion thruster
Authors: Yang Juan  , Shi Feng  , Yang Tie-Lian  , Meng Zhi-Qiang  ,   College of Astronautics, Northwestern Polytechnical University, Xi'an 710072, China
Published: December 2020

The discharge chamber is a key component of electron cyclotron resonance ion thruster. The plasma inside it is generated through a electron cyclotron resonance process. The drift and diffusion model of plasma inside the discharge chamber for numerical simulation is developed in this paper. The time dependent parameters of plasma are obtained by solving this model with upwind difference scheme. The results can provide useful information for the design and also the experiment of electron cyclotron resonance ion thruster.
Microstructures and thermoelectric properties of n-type melting spun(Bi0.85Sb0.15)2(Te1-xSex)3 compounds
Authors: Wang Shan-Yu  , Xie Wen-Jie  , Li Han  , Tang Xin-Feng  ,   State Key Laboratory of Advanced Technology for Material Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, China
Published: December 2020

The single phase n-type (Bi0.85Sb0.15)2(Te1-xSex)3(x=0.15, 0.17, 0.19, 0.21)compounds have been synthesized by melt-spinning combined with subsequent spark plasma sintering technique, and the microstructures and thermoelectric transport properties of the bulk materials have been systematically investigated. The results of field emitted scanning electron microscopy images show that the bulk materials possess refined crystalline and a large number of layered structures with the sizes from 10 nm to 100 nm, and their differences in composition and phase are detected neither from the back scattering image nor from element face distributing images of polishing surface. With the increase of content of selenium, the electrical conductivity and the thermal conductivity increase but the Seebeck coefficient decreases. Comparing with the traditional zone melted material, the samples with higher selenium content possesse higher thermoelectric optimum value ZT after 420 K and the highest ZT of the sample (Bi0.85Sb0.15)2(Te0.83Se0.17)3 can reach 0.96 at 360 K, whose ZT increases by 48% at 500 K correspondingly. In addition, the temperature of the peak ZT can be adjusted by varying the content of selenium, which is meaningful for the design and the fabrication of multi-scale or grade thermoelectric device.
The influence of root mean square phase gradient of continuous phase plate on smoothing focal spot
Authors: Feng You-Jun  , Lin Zhong-Xiao  , Zhang Rong-Zhu  ,   College of the Electronics and Information Engineering, Sichuan University, Chengdu 610064, China
Published: December 2020

In order to satisfy uniform irradiation requirement in inertial confinement fusion(ICF) system, the influence of surface characteristics of continuous phase plate on beam quality is studied in this paper. Based on wave optics and geometrical optics, theoretical analysis model is established, respectively. And the parameter, root mean square gradient, is used to unify both theoretical models. Meanwhile, the smoothing effects of root mean square phase gradient of continuous phase plate on laser beam with low-frequency aberrant wavefront are simulated. Numerical simulations show that the radius of focus spot will increase with the increase of root mean square phase gradient of continuous phase plate, and nonuniformity of beam top will decrease quickly, then reduce slowly and tend to be unchanged finally. So smoothing effect of continuous phase plate is obvious. In addition, energy availability factor has little change, then decreases gradually and reduces slowly. Spot size, nonuniformity of beam top and energy availability factor are all in a good range when the correlation length of continuous phase plate is not changed and root mean square gradient is 0.20.8 wave/mm.
Phase-dependent electromagnetically induced transparency in a four-level atom system
Authors: Yang Li-Jun  , Ma Li-Jin  , Lü Dong-Qi  , Zhang Lian-Shui  ,   College of Physical science and Technology, Hebei University, Baoding 071002, China
Published: December 2020

We present a method to control the electromagnetically induced transparency (EIT) in a four-level system with a coupling field, a weak probe field and two microwave driven fields. By sloving the density matrix equations, the numerious result is obtained. It is shown that the EIT resonance can be split into doublets and the spectral position of EIT window is determined by the relative phase between two microwave fields for fixed intensity of the microwave field. Therefore, the microwave field can be used to open more than one EIT window and by controlling their phase difference we can perform EIT frequency tuning. The structure in the spectrum can be explained using the dressed-state formalism.
Actuating frequency selection of single mode Lamb waves using single piezoelectric transducer
Authors: Zhang Hai-Yan  , Cao Ya-Ping  , Yu Jian-Bo  , Chen Xian-Hua  ,   School of Communication and Information Engineering, Key Laboratory of Specialty Fiber Optics and Optical Access Networks,Shanghai University, Shanghai 200072, China
Published: December 2020

Considering the interaction between the piezoelectric transducer (PZT) and the plate, a frequency adjusting method of generating single mode Lamb waves using single piezoelectric transducer is presented in theory. The application of mode selection in Lamb wave structural health monitoring is experimentally given. The theory has the ability to predict the amplitude of each Lamb wave mode as a function of frequency for given plate material and thickness, and specific PZT size. Optimal actuating frequency can be identified at which the wave amplitude for a particular mode is maximized while the wave amplitudes for other modes are relatively minimized. Numerical results are presented to validate the theory and show the capability of single mode Lamb wave selection. Different frequencies that correspond to a preferential A0 mode, a preferential S0 mode, and both the A0 and the S0 modes are excited for damage imaging, respectively. The results show that the single Lamb wave mode detection can locate the damage more accurately, demonstrating the importance of the mode selection in Lamb wave structural health monitoring.
Influence of impurity on Mueller matrices of randomly distributed cluster agglomerates
Authors: Lei Cheng-Xin  , Feng Dong-Tai  , Wu Zhen-Sen  ,   School of Science, Shandong University of Technology, Zibo 255049, China;,   School of Science, Xidian University, Xi'an 710071, China
Published: December 2020

The effects of impurity on the Mueller matrices of randomly distributed cluster agglomerates are analyzed. The equivalent complex refractive indees of silicate particle containing different volume fractions of amorphous carbon are obtained by the Bruggeman effective medium theory. Mueller-matrix elements of randomly distributed cluster agglomerates containing various chemical compositions are calculated by the discrete dipole approximation (DDA) method, and the profiles of Mueller-matrix elements are presented. The influence of the impurity on the Mueller matrices of randomly distributed cluster agglomerates is discussed. The results show that the influence of impurity on the Mueller matrices of randomly distributed cluster agglomerates is quite large, and it varies with the size parameters of the randomly distributed cluster agglomerates.
Shock experiment with sandwiched target in laser indirect-drive experiment
Authors: Wang Feng  , Peng Xiao-Shi  , Liu Shen-Ye  , Jiang Xiao-Hua  , Xu Tao  , Ding Yong-Kun  , Zhang Bao-Han  ,   Research Center of Laser Fusion, China Academic of Engineering and Physics, Mianyang 621900, China
Published: December 2020

Laser indirect-drive has the potential to get ultra-high pressure which is very useful for shock physics. The sandwiched target is used to suppress the ionization effect which causes the blanking area in optical streak camera (OSC) in indirect-drive experiment. The blanking effect can be avoided by the time scale and the intensity. With the thick ablator, the blanking effect appears before the shock wave arrives at the transparent material. Then the blanking effect can be avoided in time scale. With the high Z material, the X-ray which causes the blanking effect can be blocked before the transparent material. For one shock experiment, the shock wave result in Al2O3 is achieved after using the thick ablator to stagger the blanking effect and shock wave signal. The shock wave result in quartz and polystyrene material is obtained after the block layer has been added to the ablator layer. The sandwiched target provides the technique support for the equation of state and shock timing experiment in indirect-drive.
Thermal entanglement in the four-qubit Heisenberg XXZ model with the Dzyaloshinskii-Moriya interaction
Authors: Zhang Ying-Li  , Zhou Bin  ,   School of Physics and Electronic Technology, Hubei University, Wuhan 430062, China
Published: December 2020

In this paper, we study the property of thermal entanglement in four-qubit Heisenberg model, where Dzyaloshinskii-Moriya (DM) interaction is considered, and investigate the pairwise concurrences of two nearest-neighbor qubits and two next-neighbor qubits to study this entanglement property. The result shows that for the two-next-neighbor-qubit case, there exists pairwise concurrence neigher in ferromagnetic model nor in antiferromagnetic model; but for the two-nearest-neighbor-qubits case, the DM interaction and the parameter of the anisotropy exchange coupling have a significant influence on the pairwise entanglement and critical temperature Tc. Moreover, the pairwise concurrence will decrease with the increase of temperature. When the temperature execeds its critical value, the pairwise concurrence disappears. Therefore, the pairwise entanglement can be controlled and enhanced by choosing the appropriate parameters of the DM interaction and the anisotropy exchange coupling.
Investigation on strong optical activity and negative refractive index in double-layer metallic wires planar chiral structure
Authors: Li Jie  , Yang Fang-Qing  , Dong Jian-Feng  ,   Institute of Optical Fiber Communication and Network Technology, Ningbo University, Ningbo 315211, China
Published: December 2020

A planar chiral structure composed of double-layer metallic wires with fourfold symmetry is proposed. The rotation angle and the dielectric layer thickness between double-layer metallic wires is optimized. The numerical simulation results show that the exceptionally strong polarization rotation and the large chiral parameter are found at the infrared wavelength, and show a negative refraction index in a certain band.
Influence of lattice uniform strain on half-metallicity and magnetism of zinc-blende CrS and CrSe
Authors: Yao Zhong-Yu  , Fu Jun  , Gong Shao-Hua  , Zhang Yue-Sheng  , Yao Kai-Lun  ,   School of Physics and Electronic Engineering, Hainan Normal University, Haikou 571158, China;,   School of Physics, Huazhong University of Science and Technology, Wuhan 430047, China
Published: December 2020

Using the full-potential linearized augmented plane wave method based on the density functional theory, spin-polarized calculations of electronic structure for the zinc-blende CrS and CrSe are performed. Zinc-blende CrS and CrSe at their respective equilibrium lattice constants are half-metallic with the same total magnetic moment of 4.00B. The electronic structures of zinc-blende CrS and CrSe are calculated under uniform strains from -10% to +10% relative to the equilibrium lattice constant. The calculated results indicate that zinc-blende CrS and CrSe can maintain half-metallic ferromagnetism and keep the same total magnetic moment of 4.00B from -1% to 10% and from -4% to 10% uniform strain, respectively.
Study on third-order optical nonlinearity of GeS2-Ga2S3-CsCl chalcohalide glasses
Authors: Li Zhuo-Bin  , Lin Chang-Gui  , Nie Qiu-Hua  , Xu Tie-Feng  , Dai Shi-Xun  ,   Laboratory of Infrared Material and Devices, Ningbo University, Ningbo 315211, China;,   Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
Published: December 2020

Chalcohalide glasses with compositions of (100-2x) GeS2-xGa2S3-xCsCl (x= 15, 20, 25) are synthesized by the conventional melt-quenching method. Third-order optical nonlinearities of these glasses are studied using the Z-scan technique. The relationship between photon energy and optical nonlinearity is analyzed. Moreover, the effect of glass composition on the third-order nonlinearity is investigated. The results show that just a small variation of the excitation photon energy causes the value of samples to change in a large range. The value increases with the enhancement of excitation photon energy. When the photon energy is close to 0.5 Eg, the value is close to 0 and the factor of quality of the glass reaches an optimal value. The increase of CsCl content enlarges the optical band gap Eg, which leads to the blue-shift toward the short edged wavelength, and lowers the value. However, the value varies little because of the opposite effect on the optical nonlinearity between the structure and the band gap Eg. In this work, the optical nonlinearity is shown to be dependent on band gap and structure, and the results have a certain directive significance and reference value for future research.
Morphology control of gold nanoparticles on glass surface realized by electric field assisted dissolution method
Authors: Zou Zhi-Yu  , Liu Xiao-Fang  , Zeng Min  , Yang Bai  , Yu Rong-Hai  , Jiang He  , Tang Rui-He  , Wu Zhang-Ben  ,   School of Materials Science and Engineering, Beihang University, Beijing 100191, China;,   Department of Materials Science and Engineering, Tsinghua University, Beijing 100084, China
Published: December 2020

Noble metal nanoparticles have potential applications in photonics, catalysis, and bio-labeling, owing to their much unique optical properties and surface activities. Monodisperse spherical Au nanoparticles with sizes in a range of about 60-80 nm are formed on the glass surfaces via ion sputtering and follow-up heat treatment. At an appropriate temperature, the electric field assisted dissolution process of Au nanoparticles is realized by the strong direct current electric field in step-like feature. In the different color areas of glass surface, it can be found that the original spherical Au nanoparticles are dissolved into the particles with the shape of a lunar eclipse. From surface plasmon resonance absorption properties and scattering electron microscopy images of Au nanoparticles in the different color areas, the influence of experimental condition on property of gold nanoparticle is demonstrated. From the current-voltage characteristics in electric field assisted dissolution experimental process, the physical process of Au nanoparticle dissolution under strong direct current electric field is analysed: the tunneling process of ejected electrons from Au particles to the anode starts, then followed by transfer process of Au cations to the glass matrix and the combination process of electrons from cathode with a positive charge Au particles. The physical mechanism of morphology control of Au nanoparticles realized by electric field assisted dissolution method is discussed in detail.
Local resonant acoustic band gaps in two-dimensional square-arranged Helmholtz resonators array
Authors: Liu Min  , Hou Zhi-Lin  , Fu Xiu-Jun  ,   Department of Physics, South China University of Technology, Guangzhou 510640, China
Published: December 2020

In this paper, by taking the acoustic property of a two-dimensional squarely arranged Helmholtz resonator array for example, we point out that there exist two kinds of couplings in the local resonance phononic crystal, which are the coupling between the resonator and background and the coupling among the resonators, respectively. The first coupling effect can be changed by changing the quality factor of the resonator. A local-resonant type of band gap can be converted into a Bragg-scattering type continually when this kind of coupling becomes larger and larger. The second one, which is based on the overlapping of the near filed around the resonators, can be enhanced by reducing the distance between the nearest resonators. As a result, a wider band gap, but a smaller penetration depth of the wave, can be obtained.
Exciton states and optical properties in zinc-blende GaN/AlGaN quantum dot
Authors: Wang Yan-Wen  , Wu Hua-Rui  ,   Department of Life Science and Technology, Xinxiang Medical University, Xinxiang 453003, China;,   Department of Physics, Xinxiang University, Xinxiang 453003, China
Published: December 2020

Within the framework of effective-mass approximation, exciton states confined in zinc-blende GaN/AlGaN quantum dot (QD) are investigated by a variational approach, including the three-dimensional confinement of electron and hole in the QD and the finite band offset. Numerical results show that both the exciton binding energy and the interband emission energy decrease when QD height (or radius) increases. Our theoretical results are in agreement with the experimental measurements.
A new chaotic system and its implementation
Authors: Li Chun-Lai  , Yu Si-Min  , Luo Xiao-Shu  ,   College of Automation, Guangdong University of Technology, Guangzhou 510006, China;,   College of Electronic Engineering, Guangxi Normal University, Guilin 541004, China;,   College of Physics and Electronics, Hunan Institute of Science and Technology, Yueyang 414006, China
Published: December 2020

Based on the construction patterns of Chen and Liu chaotic systems, a new chaotic system is proposed by developing the Lorenz chaotic system. The essential features of chaotic system are analyzed via equilibrium, stability, continuous spectrum, and Poincare mapping. The different dynamic behaviors of the system are analyzed especially when each system parameter changes. It is found that when parameters d and e vary, the Lyapunov exponent spectrum keeps invariable, and there exist the functions of global nonlinear amplitude adjuster for d and partial nonlinear amplitude adjuster for e. Finally, a practical circuit is designed to implement this new chaotic system, which confirms that the chaotic system can be achieved physically.
Analysis of weight Lempel-Ziv complexity in piecewise smooth systems of DC-DC switching converters
Authors: Xie Fan  , Yang Ru  , Zhang Bo  ,   School of Electric Power, South China University of Technology, Guangzhou 510640, China;,   School of Physics and Electronic Engineering, Guangzhou University, Guangzhou 510006, China
Published: December 2020

A novel concept of switching block is presented via detecting the switching behavior of each switching period in piecewise smooth system of DC-DC switching converter, and logical arithmetic method of computer is used to obtain decimal system from binary system, so complex degree of the system during one switching period is quantized as switching block and the symbolic time sequence of the piece smooth system is established. Weight Lempel-Ziv (L-Z) complexity is derived based on the L-Z complexity and the symbolic time sequence, and the qualitative analysis of nonlinear and complex degree in piecewise smooth system from symbolic time sequence with single variable is carried out. The motion rule and the dynamics structure of the whole system are revealed. Finally, The present current mode controlled buck converter is studied as an example to establish symbolic time sequence and to illustrate the applications of weight L-Z complexity.
Dynamical analysis of linear single degree-of-freedom oscillator with fractional-order derivative
Authors: Shen Yong-Jun  , Yang Shao-Pu  , Xing Hai-Jun  ,   Department of Mechanical Engineering, Shijiazhuang Tiedao University, Shijiazhuang 050043, China
Published: December 2020

A linear single degree-of-freedom oscillator with fractional-order derivative is researched by the averaging method, and the approximately analytical solution is obtained. The effects of the parameters on the dynamical property, including the fractional coefficient and the fractional order, are characterized by the equivalent linear damping coefficient and the equivalent linear stiffness, and this conclusion is entirely different from the published results. The comparison of the analytical solution with the numerical results verifies the correctness of the approximately analytical results. The following analysis on the effects of the fractional parameters on the amplitude-frequency is fulfilled, and it is found that the fractional coefficient and the fractional order could affect not only the resonance amplitude through the equivalent linear damping coefficient, but also the resonance frequency by the equivalent linear stiffness.
Large dynamic range receiving technology with energy consumption based on wake lidar
Authors: Liang Shan-Yong  , Wang Jiang-An  , Zhang Feng  , Shi Sheng-Wei  , Ma Zhi-Guo  , Liu Tao  , Wang Yu-Hong  ,   Electronic Engineering College, Naval University of Engineering, Wuhan 430033, China
Published: December 2020

The multiple scattering of underwater lidar for wake happens in the near field, which leads ordinary receiving system to be saturated due to lack of dynamic range. The receiving system recovery time is usually up to several nanoseconds, which affects the receiving of the far-field signal. For this problem, the attenuation law of laser back-scattering intensity by water is analyzed and a front-end receiver of underwater lidar with energy consumption is developed. A high-speed reverse transient cancellation current is superimposed on the strong peak of near-field part signal to prevent the receiving system from being saturated, thereby restoring the two signals to integrated returned signal waveform. The technical difficulties are analyzed and the solutions are presented. The influence of generation time of transient cancellation current on intensity is discussed. The results of measurement and analysis prove that the transient cancellation current is 5 ns in pulse width, its adjustable step of 122 nA and the adjustable range is 135360 upA. The system suppresses the near-field strong scattering signal successfully and can meet the requirement for the underwater large dynamic range lidar for wake.
Uncertainties of nucleo-chronometers from nuclear physics inputs
Authors: Zhang Wei-Hong  , Niu Zhong-Ming  , Wang Feng  , Gong Xiao-Bo  , Sun Bao-Hua  ,   State Key Laboratory of Software Development Environment, School of Physics and Nuclear Energy Engineering, Beihang University, Beijing 100191, China;,   Department of Physics, Anhui University, Hefei 230039, China
Published: December 2020

The influences of uncertainties in nuclear physics inputs on the Th/U, Th/Hf, Th/Eu, Th/Os, Th/Ir nucleo-chronometers are investigated in the framework of the classical r-process approach. A Monte-Carlo method is used to evaluate the age uncertainty originating from neutron separation energies for each nuclear mass model. It is found that the deduced age uncertainty for Th /U can be up to 1.66 Ga, and for the three chronometers, Th/Eu, Th/Os, Th/Ir, the uncertainties are 5.15 Ga, 3.93 Ga and 3.95 Ga, respectively. The recently proposed chronometer, Th/Hf, shows a clear model dependence, while Th/Os and Th/Ir chronometers tend to overestimate the age of Universe. Taking into account the uncertainties in nuclear physics inputs and observations, an up-to-date age estimation for the universe with the Th/U chronometer is 14.1? 3.8 Ga.
First-principles study of the electronic structure and absorption spectrum of heavily Nd-doped anatase TiO2
Authors: Zhang Zhen-Duo  , Hou Qing-Yu  , Li Cong  , Zhao Chun-Wang  ,   College of Sciences, Inner Mongolia University of Technology, Hohhot 010051, China
Published: December 2020

According to the plane wave ultra-soft pseudo potential technique of density function theory, we perform the first-principles study of the electronic structure and absorption spectrum of heavily Nd-doped anatase TiO2 with different Nd concentrations, along with those of pure anatase TiO2. The calculation results show that, within the concentration range of Nd set by this article, with the doping concentration decreasing, the band gap becomes narrow, and the absorption spectrum is red shifted more considerably. The experimental results are in accordance with the calculation results.
Chaotic immune optimization based resource allocation in cognitive radio network
Authors: Chai Zheng-Yi  , Zheng Li-Ping  , Zhu Si-Feng  ,   School of Information Science and Engineering, Henan University of Technology, Zhengzhou 450001, China
Published: December 2020

In order to optimize the multi-user subcarrier allocation of cognitive wireless network, it is converted into a constraint optimization problem. A chaotic immune optimization algorithm is proposed to solve it. The key techniques and implementation processes are given. The operators, such as coding, clonal, crossover, and mutation, are designed. The experimental results show that in conditions of user rate, the bit error rate and inference constraints, the algorithm minimizes the total transmit power and converges rapidly. It can obtain the better allocation scheme and improve the utilization efficiency of high frequency spectrum.
To understand earthquake from the granular physics point of viewcauses of earthquakes, earthquake precursors and prediction
Authors: Lu Kun-Quan  , Hou Mei-Ying  , Jiang Ze-Hui  , Wang Qiang  , Sun Gang  , Liu Ji-Xing  ,   Key Laboratory of Soft Matter Physics, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China;,   Department of Applied Physics, Harbin Institute of Technology, Harbin 150001, China;,   Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing 100190, China
Published: December 2020

To recognize the seismogenic process, mechanism and behavior of seismic precursors, as well as look for the ways of earthquake prediction the granular physics principle is applied based on the basic structure of the crust and mantle and existing experimental observations, where we treat the earth crust and mantle as large scale discrete matters. Main outcomes are: A granular model of the structure and movement of the earth crust and mantle is established. A formation mechanism of the tectonic forces, which causes the earthquakes, and a model of propagation for precursive signals are proposed. Properties of the seismic precursive signal and its relevance with the earthquake occurrence are illustrated, and principle of ways to detect the effective seismic precursor is elaborated. In the paper the mechanism of palintectic earthquake is also explained by the jamming-unjamming transition of the granular flow. Some earthquake phenomena which were previously difficult to understand are explained, and the predictability of the earthquake is discussed. Due to the discrete nature of the earth crust and mantle, the continuum theory no longer applies during the quasi-static seismogenic process. In all in this paper, based on granular physics, we study the causes of earthquakes, earthquake precursors and earthquake prediction, and a new understanding, different from the traditional seismological point of view, is obtained.
The asymptotic solving methodof traveling wave solution to a class of sea-air coupled oscillator model
Authors: SHI Lan-Fang  , Ouyang Cheng  , Mo Jia-Qi  ,   College of Mathematics and Physics, Nanjing University of information Science and Technology, Nanjing 210044, China;,   Faculty of Science, Huzhou Teacher College, Huzhou 313000, China;,   Deprtment of Mathematics, Anhui Normal University, Wuhu 241003, China
Published: December 2020

The tropical sea-air oscillator is a complicated natural phenomenon. In this paper, based on a sea-air oscillator model, by a new method of combining the undetermined coefficients with the perturbation theory the asymptotic traveling wave solution of the corresponding model is obtained.
Numerical simulation of soliton trapping of the supercontinuum in photonic crystal fiber
Authors: Li Jian-Feng  , Zhou Gui-Yao  , Hou Lan-Tian  ,   Institute of Infrared Optical Fibers and Sensors, Yanshan University, Qinhuangdao 066004, China;,   State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 China;,   School for Information and Optoelectronic Science and Enginering, South China Normal University, Guangzhou 510006, China
Published: December 2020

In this paper, we numerically study the soliton trapping of supercontinuum in photonic crystal fiber by solving generalized nolinear Schrödinger equation. Using the cross-correlation frequency resolved optical gating (X-FROG) technique, the propagation of the supercontinuum is recorded along the fiber and the evolution of soliton trapping is observed. When the phase-matching condition is met, new frequency of the pulse trapping is generated from four-wave mixing of soliton with nonsolitonic radiation, and is continuously blueshifted while the soliton is redshifted. Higher pump-power shows the strong interaction between soliton and nonsolitonic radiation. Provided in the paper is a theoretical basis for tunable ultra-short laser pulses and supercontinuum researches.
Two-site Hubbard-holstein model polaron of quantum entanglement properties
Authors: Ren Xue-Zao  , He Shu  , Cong Hong-Lu  , Wang Xu-Wen  ,   School of Science, Southwest University of Science and Technology, Mianyang 621010, China
Published: December 2020

We obtain the exact solution of energy spectrum and dynamics for the two-site Hubbard-Holstein model by the coherent states orthogonal expansion method. The influences of coupling strength g, the average number of phonons n and the initial electronic state on the evolution of system entanglement and von Neumann entropy are discussed. Numerical results are as follows. (a) Entanglement evolution with time shows a good periodicity. When the other parameters are fixed, the evolution period decreases as the coupling strength g goes up but it is independent of the average number of phonons n. (b) The von Neumann entropy of the system demonstrates strict synchronia with the electronic state occupancy probability. (c) Under the weak coupling strength and low average number of phonons, the initial electronic state c2+ c2+|Oe or c1+ c1+|Oe shows larger maximum von Neumann entropy during its evolution than that of c1+c2+c1+c2++ but they gradually approach to each other with the increase of coupling strength or average number of phonons.
Effect of particle density on the segregation of binary granular systems in a rotating drum
Authors: Huang De-Cai  , Feng Yao-Dong  , Xie Wei-Mei  , Lu Ming  , Wu Hai-Ping  , Hu Feng-Lan  , Deng Kai-Ming  ,   Department of Applied Physics, Nanjing University of Science and Technology, Nanjing 210094, China;,   School of Chemical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
Published: December 2020

The effects of particle density on the segregation of binary granular systems in a rotating drum are studied by the molecular dynamics simulation. The results show that the Brazil nut effect happens when the density of small granules is larger, whereas as the density of big granule increases, the segregation pattern is reversed and the reverse Brazil nut effect occurs. We also calculate the quantitative relationship between the segregation index and the density ratio. Finally, the mechanism of competition between percolation and condensation from Hong's theory is used to explain theoretically the reversion of segregation pattern.
Wavelength tunable properties for distributed feedback lasing from dye-doped holographic polymer dispersed liquid crystal transmission grating
Authors: Deng Shu-Peng  , Huang Wen-Bin  , Liu Yong-Gang  , Diao Zhi-Hui  , Peng Zeng-Hui  , Yao Li-Shuang  , Xuan Li  ,   State Key Laboratory of Applied Optics, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, China;,   Graduate university of Chinese Academy of Sciences, Beijing 100049, China
Published: December 2020

In this paper, we study the wavelength tunable properties for distributed-feedback lasing from 4-(dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4H-pyran (DCM) dye-doped holographic polymer dispersed liquid crystal grating. By preparing and pumping the DCM-doped HPDLC gratings with various grating spacings, we depict the tuning curve of the distributed-feedback lasing and confirm that only in a range from 574 nm to 685 nm, the lasing action can be observed. Then, we adjust the temperature of the sample and measure the lasing spectrum from the DCM-doped holographic polymer dispersed liquid crystal grating with a grating period of 610nm. There is an obvious 4.9 nm blueshift from 627.9 nm to 623 nm for the lasing wavelength with the temperature increasing from 20℃ to 65℃.
Design and analysis of thermally tunable liquid-crystal-filled microstructured polymer optical fiber
Authors: Wang Dou-Dou  , Wang Li-Li  , Li Dong-Dong  ,   State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Science, Xi'an 710119, China
Published: December 2020

A highly tunable bandgap-guiding microstructured polymer optical fiber (mPOF) is designed by infiltrating the cladding air holes with a liquid crystal. Bandgap is blue shifted as temperature is increased. A high thermal tuning sensitivity of -5.5 nm/℃ is achieved at the long-wavelength edge of the bandgap. Mode properties and effective mode area of the fundamental mode are investigated by using the full-vector finite element method. The designed fiber has a large effective area and high power transmission coefficient between the index guiding modes and the bandgap guiding modes. Our results provide theoretical references for applications of mPOF in sensing and tunable fiber-optic devices.
Research of Chaotic encryption system based on FPGA technology
Authors: Liu Qiang  , Fang Jin-Qing  , Zhao Geng  , Li Yong  ,   Department of Nuclear Technology Application, China Institute of Atomic Energy, Beijing 102413, China;,   Department of Computer Science and Technology, Beijing Electronic Science and Technology Institute, Beijing 100070, China
Published: December 2020

In this paper, a kind of chaos encryption system is presented based on chaotic encryption algorithm and traditional encryption algorithm, and hardware is implemented by using the FPGA technology. According to discrete and digital technologies, Henon Map and Logistic Map are applied, and chaotic iteration sequence is generated by using Verilog HDL language and FPGA technology. By combining the traditional iteration algorithm, the files are encrypted and decrypted. Based on Xilinx FPGA exploitation platform, secret communication experiments on Internet are successefully. The devise has potential prospective applications in internet secrecy communication.
Viscosity coefficient in granular medium
Authors: Qian Zu-Wen  ,   Acoustics Institute, Chinese Academy of Sciences, Beijing 100190, China
Published: December 2020

A granular medium can be regarded as an equivalent uniform medium, of which the attenuation coefficient and the acoustic speed are obtained from the author's theory published elsewhere. The equivalent static density can be given by the mixed rule. According to the author's sound propagation theory in the granular medium, furthermore, the secondary waves are plane waves as well when the incidental sound wave is plane wave. In these cases, the three-dimensional equations can be simplified into a one-dimensional equation, and an expression for the viscosity coefficient in concentrated granular medium can be obtained. The theoretical results show that the viscosity coefficient depends on not only the volume fraction of the grains, but also sound frequency. On the other hand, the theory given in this paper can be used in the realistic cases, where less restrictions will be imposed on the applications than the Einstein's theory.
Research on the influences of point defects on the thermal conductivity of carbon nanotube by simulation with orthogonal array testing strategy
Authors: Li Wei  , Feng Yan-Hui  , Chen Yang  , Zhang Xin-Xin  ,   Department of Thermal Science and Energy Engineering, University of Science and Technology Beijing, Beijing 100083, China
Published: December 2020

In the preparation process of carbon nanotubes, various point defects inevitably come into being in the lattice structures. The defects strongly affect the thermal transport properties of carbon nanotubes. Thermal conduction in carbon nanotube is simulated by using nonequilibrium molecular dynamics method with reactive bond order (REBO) potential. Thermal conductivities of carbon nanotubes with and without defects are calculated for comparison. An orthogonal array testing strategy is employed. In the calculation it greatly saves the experimental effort and identifies the degrees of influence of such structural factors as defect type, tube length, tube radius, etc. on thermal conductivity of tube. The effects of three types of point defects: vacancy, doping and adsorption are primarily studied, and the ambient temperature factor is also analyzed. Simulation results show that the thermal conductivity of carbon nanotubes with defects decreases significantly due to point defects compared with that of perfect carbon nanotubes. The defect type has the first greatest influence on the decrease of thermal conductivity, and hvae the second third greatest infuluences respeetively the radius and the length of carbon nanotubes. The degrees of influence of the above types of point defect are in the order of vacancydopingadsorption. Different types of point defects have different effects on tubes at different ambient temperatures.
Study on spatiotemporal chaos network synchronization of the laser Maxwell-Bloch equation
Authors: Lü Ling  , Shang Jin-Yu  , Zhu Jia-Bo  , Shen Na  , Liu Shuang  , Zhang Xin  ,   College of Physics and Electronic Technology, Liaoning Normal University, Dalian 116029, China
Published: December 2020

Spatiotemporal chaos network synchronization of the laser Maxwell-Bloch equation is studied. The single-mode laser Maxwell-Bloch equation is amended. Then N single-mode laser Maxwell-Bloch equations amended are taken as nodes to constitute a complex network. Considering the fact that the parameters of the spatiotemporal chaos systems taken as nodes may have small deviations from the actual values because of some interference in the network connecting process, the system at the first node is take as a driven system to drive the rest of the N-1 systems in parallel to achieve synchronization. Furthermore, simulation is performed to verify the effectiveness of the method.