bluuebunny/crossref_metadata_2025 huggingface dataset:
Study on the ground-state splitting and the local lattice distortion of α-Al2O3：Fe3+ system
Authors: Wu Zhi-Yan  , Kuang Xiao-Yu  , Li Hui  , Mao Ai-Jie  , Wang Zhen-Hua  ,   Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, China
Published: December 2020

Electron paramagnetic resonance (EPR) spectra for Fe3+ in sapphire were measured and studied by Scholz and Buzaré in 2002. Their analysis shows that the ground-state splitting for Fe3+ in sapphire may be associated with two distortion angles Δθ and Δφ. By diagonalizing 252×252 complete energy matrix for the d5 configuration ion in C3 symmetry ligand-field, in this paper a systematic investigation about the ground-state splitting for Fe3+ in sapphire is given. Our results indicate that the 6A1 ground-state splitting are sensitively dependent on the local lattice distortion along the two directions, respectively, which supports the Scholz and Buzaré’s opinion. Meanwhile, by simulating the optical spectra and the EPR spectra for Fe3+ in sapphire, the local lattice distortion parameter Δθi can be obtained.
General solution of Schrödinger equation and electron transition in superlattice multi-quantum well
Authors: Luo Xiao-Hua  ,   Library, Chongqing Jiaotong University, Chongqing 400074, China
Published: December 2020

Supposing that the quantum well of a superlattice is a periodic potential well of an arbitrary shape, the motion problem of electrons in the superlattice can be reduced into the motion in a periodic field. From the Schrödinger equation and its general solution, the dispersion equation of the system can be derived using Bloch theory and the transfer matrix method in the framework of quantum mechanics; and the electronic transitions of the multi-quantum well for the superlattice can be discussed in parabolic approximation. Results show that the radiation energy is located at the infrared, far infrared or terahertz band.
Fabrication and optical property characterization of quantum-dot-array diffraction grating with single order diffraction based on focused ion beam
Authors: Huang Cheng-Long  , Zhang Ji-Cheng  , Diao Kai-Di  , Zeng Yong  , Yi Yong  , Cao Lei-Feng  , Wang Hong-Bin  ,   State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials, Southwest University of Science and Technology, Mianyang 621010, China;,   Laboratory for Extreme Conditions Matter Properties, Southwest University of Science and Technology, Mianyang 621010, China;,   Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900, China
Published: December 2020

Quantum-dot-array diffraction grating(QDADG), with an area of 200 μm×200 μm, a line density of 500 line/mm, an aperture size of 800 nm and a gold absorber of 500 nm thick, is successfully fabricated by focused ion beams. The diffraction properties and relative diffraction efficiencies of QDADG are measured at different transfer distance for 442 nm laser. It is shown that the high-order diffraction is removed from the spectra with only the ±1 and 0 order diffraction lines reserved. Moreover, in accordance with the calculated values obtained using the grating equation, variations of space between the 1st order and the 0th order increase gradually with the increase of transfer distance.
Experimental researches of a four-cavity intense relativistic klystron amplifier
Authors: Cheng Hui  , Xie Hong-Quan  , Liu Ying-Hui  , Li Zheng-Hong  , Wu Yang  ,   School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu 610000, China;,   Science and Technology on High Power Microwave Laboratory, Institute of Applied Electronics, CAEP, Mianyang 621900, China;,   Southwest University of Science and Technology, Mianyang 621010, China
Published: December 2020

This paper described a high-order mode oscillation phenomenon, in the simulation of four-cavity intense relativistic klystron amplifier(IRKA). And we have analyzed the cause of this kind of oscillation, and explored the suppression methods for the whole tube. Two-dimensional and three-dimensional electromagnetism simulation software are used to study the influence of parameter’s changes (such as the oscillation frequency of cavities, the cavity Q value, the length of drift tube, and the characteristic impedance) on the high-order mode oscillation. The effectiveness of the high-order mode oscillation suppression methods is verified by simulation. Then, by optimizing the structure of IRKA, we have achieved an output microwave with a power of 2.13 GW, a gain of 60 dB and an efficiency of 26% in simulation, and the high-mode oscillation is avoided effectively. Finally, an output microwave with a power of 1.9 GW, a gain of 61 dB, and an efficiency of 24% is gained in the experiment.
Synergistic effects of total ionizing dose on the single event effect sensitivity of static random access memory
Authors: Xiao Yao  , Guo Hong-Xia  , Zhang Feng-Qi  , Zhao Wen  , Wang Yan-Ping  , Ding Li-Li  , Fan Xue  , Luo Yin-Hong  , Zhang Ke-Ying  ,   State Key Laboratory of Intense Pulsed Radiation Simulation and Effect, Northwest Institute of Nuclear Technology,Xi’an 710024, China;,   Xinjiang Technical Institute of Physics and Chemistry Chinese Academy of Science, Urumqi 830011, China;,   State Key Laboratory of Electronic Thin Films and Integrated Devices, Chengdu 610054, China
Published: December 2020

The single event effect sensitivity of static random access memory(SRAM) under different cumulative dose were carried out using 60Co source and heavy ions. The trend of sensitivity was obtained and the radiation damage mechanism was analyzed theoretically. This investigation shows that the variation in single event upset cross section with increasing accumulated dose appears to be consistent with the radiation-induced leakage current originating in the memory cells that affects the parameters such as low-level hold voltage and high-level fall time and induces con-imprint effect. Results obtained support the reliability analysis of the aerospace devices in space radiation environment.
Image reconstruction based on total variation minimization and alternating direction method for Compton scatter tomography
Authors: Gu Yu-Fei  , Yan Bin  , Li Lei  , Wei Feng  , Han Yu  , Chen Jian  ,   National Digital Switching System Engineering and Technological Research Center, Zhengzhou 450002, China
Published: December 2020

Compton scatter tomography measures samples electron densities utilizing the scattered photons. Compared to traditional transmission imaging models, Compton scatter tomography has the following characteristics, i.e. freedom in construction systems, greater sensitivity for low-density materials, and lower radiation dose. It has been applied in non-destructive testing, medical, and security inspections, and other fields. However, Compton scatter tomography reconstruction is a nonlinear inverse problem, common is ill-posed, and its solutions are very sensitive to noise and erroneous measurements. To tackle the problem, in this paper we propose a novel Compton scatter tomography reconstruction algorithm based on the total variation minimization and alternating direction method. The main idea of our method is to reformulate the reconstruction problems TV function as an optimization with constrains where the objective function is separable, and then minimize its augmented Lagrangian function by using alternating direction method to solve the sub-problems. Numerical experiments shows that the reconstruction quality and efficiency of the proposed method are improved compared to the adaptive-steepest-descent-projection onto convex sets method.
Fabrication of flexible Cu2ZnSnS4 (CZTS) solar cells by sulfurizing precursor films deposited via successive ionic layer absorption and reaction method
Authors: Sun Kai-Wen  , Su Zheng-Hua  , Han Zi-Li  , Liu Fang-Yang  , Lai Yan-Qing  , Li Jie  , Liu Ye-Xiang  ,   School of Metallurgy and Enviroment, Central South University, Changsha 410083, China;,   School of Photovoltaic and Renewable Energy Engineering, University of New South Wales, Sydney, 2052 Australia;,   Engineering Research Center of High Performance Battery Materials and Devices, Shenzhen 518057, China
Published: December 2020

Cu2ZnSnS4 (CZTS) precursor thin films were prepared on a flexible Mo foil substrate via ZnS/Cu2SnSx stacked structure using successive ionic layer absorption and reaction (SILAR) method; the precursor thin films were annealed at 550 ℃ in sulfur atmosphere to obtain CZTS absorber layers. The chemical composition,crystallinity and surface morphology were characterized by EDS, XRD, Raman and SEM, respectively, indicating that the annealed films are highly crystallin and have compact morphology. In order to analyse the optical and electrical properties of the films, same processes were implemented on the soda glasses. Results reveal that the band gaps of the annealed films are 1.49 eV, the absorption coefficients are higher than 104 cm-1, and the carrier concentration as well as the electrical resistivity is suitable for fabrication of thin film solar cells. Flexible solar cells with a structure of Mo foil/CZTS/CdS/i-ZnO/ZnO: Al/Ag were fabricated by the above CZTS absorber layers, which demonstrated an efficiency of, 2.42%, the record efficiency of flexible CZTS solar cells as far as we know.
Noise suppression for magnetotelluric sounding data based on signal subspace enhancement and endpoint detection
Authors: Li Jin  , Tang Jing-Tian  , Wang Ling  , Xiao Xiao  , Zhang Lin-Cheng  ,   Institute of Physics and Information Science, Hunan Normal University, Changsha 410081, China;,   Key Laboratory of Metallogenic Prediction of Nonferrous Metals, Ministry of Education, School of Geosciences and Info-Physics, Central South University, Changsha 410083, China
Published: December 2020

To retain useful information of magnetotelluric low frequency band and improve the capacity of magnetotelluric deep detection in ore concentration area with complex noises, the combined signal subspace enhancement with endpoint detection is proposed based on morphology filtering to secondary signal-to-noise separation processing. Firstly, aimed at noise contour extracted by morphology filtering, we use signal subspace enhancement to separate signal subspace and noise subspace for pretreatment. Secondly, the signal subspace is combined with reconstructed signal and the noise subspace is set to zero. Finally, endpoint detection for post-processing is carried out in order to identify the start and end points of the waveform mutation. Simulated results show that Cagniard resistivity curve in the low frequency band has been improved obviously, and the apparent resistivity value is relatively stable. The proposed method is better to offset the loss of low frequency useful information in the process of the morphological filtering, and the results can even more truly reflect the inherent deep structural information of low frequency components for the measured point itself.
Evolutionary modeling for parameter estimation for chaotic system
Authors: Wang Liu  , He Wen-Ping  , Wan Shi-Quan  , Liao Le-Jian  , He Tao  ,   National Climate Center, China Meteorological Administration, Beijing 100081, China;,   School of Computer Science and Technology, Beijing Institute of Technology, Beijing 100081, China;,   Yangzhou Meteorological office, Yangzhou 225009, China;,   Changzhou Environment Monitoring Center, Changzhou 213000, China
Published: December 2020

On the basis of evolutionary algorithm, a novel method for parameter estimation of nonlinear dynamic equations is given in the present paper. Numerical tests indicate that the unknown parameters all can be estimated quickly and accurately whether the partial parameters are unknown or all parameters are unknown in the classic Lorenz equation. However, it is found that the convergence rate of the new algorithm is relatively slow when multiple unknown parameters are estimated simultaneously. To solve this problem, a corresponding improvement of measure is proposed, namely, a constraint mechanism is taken during the variation operation of evolutionary algorithm. The improvement is mainly based on the characteristic that the longer the running time of the evolutionary algorithm, the smaller the range of variation of the estimated parameters. Results indicate that the searching speed of the algorithm is greatly improved by using the improved estimation parameter project.
Iterative learning control for discrete time-varying switched systems
Authors: Cao Wei  , Sun Ming  ,   College of Computer and Control Engineering, Qiqihar University, Qiqihar 161006, China
Published: December 2020

Aiming at the problem of trajectory tracking in a class of discrete time-varying switched system with arbitrary sequence, in this paper we propose a discrete iterative learning control algorithm. Under the precondition that the switched sequence does not change along the iterative axis but it does along the time axis, this algorithm divides the whole finite time region into several finite subintervals, and uses -norm to prove the convergence strictly, and provides the sufficient convergent condition of the algorithm in the norm form. This method not only realizes the complete tracking for a discrete time-varying switched system within a limited time, but also has a simple structure easy to be realized in engineering. Simulation results verify the validity of the method.
Entanglement dynamics of two cavities interacting with reservoir in noninertial frame
Authors: Liang Yan  , Wu Qi-Cheng  , Ji Xin  ,   Department of Physics, College of Science, Yianbian University, Yanji 133002, China
Published: December 2020

We investigate the entanglement dynamics of two cavities interacting respectively with reservoir in non-inertial frames. We consider not only the influence of acceleration, but also the influence of different rates between right and left components of the Unruh single-particle state on entanglement. The result shows that the reservoir-entanglement will increase with the decrease of the cavity-entanglement when the acceleration parameter is fixed. In addition, there appears the redistribution of entanglement between particle mode and antiparticle mode, when the initial state is in a maximal by entangled state with |qR|=1. We also find that the sudden death of entanglement happens in infinite acceleration limit when |qR|=|qL|=1/√2, whereas the death of entanglement happens at finite acceleration when qR2.
Stability for amplitude spiral wave in complex Ginzburg-Landau equation
Authors: Gao Ji-Hua  , Wang Yu  , Zhang Chao  , Yang Hai-Peng  , Ge Zao-Chuan  ,   Key Laboratory of Special Functional Materials of Shenzhen, College of Materials, Shenzhen University, Shenzhen 518060, China
Published: December 2020

The study of a novel amplitude spiral wave in complex Ginzburg-Landau equation system is performed. The competition results between amplitude spiral waves and phase spiral waves and spatiotemporal chaos can be divided into four kind of regimes: regimes I and Ⅲ, in which the space of amplitude spiral waves is invaded by phase spiral waves, regime Ⅱ, in which the amplitude spiral waves are stronger than phase spiral waves, and regime IV, in which we have various results due to the existence of spatiotemporal chaos. Analysing the frequencies of amplitude spirals, phase spirals and spatiotemporal chaos, we find that when the parameters of spiral wave system α1=-1.34 and β1=0.35, the spiral wave with higher frequency will have better stability and can invade into low-frequency pattern space. The competition results are influenced by frequency of real part of the system variable. Our frequency analyses accord well with the numerical observations.
Dimensionality reduction modeling and characteristic analysis of memristive circuit
Authors: Bao Bo-Cheng  , Wang Chun-Li  , Wu Hua-Gan  , Qiao Xiao-Hua  ,   School of Information Science and Engineering, Changzhou University, Changzhou 213164, China;,   Department of Electronic Engineering, Nanjing University of Science and Technology, Nanjing 210094, China;,   School of Electrical and Information Engineering, Jiangsu University of Technology, Changzhou 213001, China
Published: December 2020

Through mathematical modeling analysis of Chua’s memristive circuit, the problem of dimensionality reduction for dynamical modeling of memristive circuit is proposed. Taking memristive circuit with two memristors for example, dimensionality reduction modeling of the memristive circuit is performed, on which a three-dimensional system model is established. Based on this model, the equilibrium points and stabilities are analyzed, and the dynamical characteristics, when the parameters are varied, are investigated. Furthermore, the analysis results from the conventional model are compared with the results from the dimensionality reduction model of memristive cicuit with two memristors. The results indicate that the dimensionality of the dimensionality reduction model of memristive circuit is related to the number of capacitors and inductors only, but unrelated to the number of memristors; there exist nonlinear phenomena about the coexistence of bifurcation modes in the memristive circuit when circuit parameters are varied; the dimensionality reduction modeling reduces the complexity of system modeling, which is conducive to dynamical charateristic analysis of the system but eliminates the effect of the initial conditions of the memristors internal state variables on dynamical charateristics of memristive circuit.
A novel image authentication and recovery algorithm based on chaos and Hamming code
Authors: Wang Xing-Yuan  , Zhang Ji-Ming  ,   Faculty of Electronic Information and Electrical Engineering, Dalian University of Technology, Dalian 116024, China
Published: December 2020

In this article, we propose an image authentication and a recovery algorithm based on chaos and Hamming code. In this algorithm, the Hamming code that is widely used in the channel coding is used, the error control is applied to the image authentication and recovery, and the validity and security of the algorithm are ensured by chaotic mapping. Analytical and experimental results show that the algorithm has a good visual effect and an effectively tampering detection ability with less embedding authentication information, at the same time the algorithm can recover a tampered image to some extent.
The band inversion and topological insulating state of Heusler alloys：X2RuPb (X=Lu, Y)
Authors: Wang Xiao-Tian  , Dai Xue-Fang  , Jia Hong-Ying  , Wang Li-Ying  , Liu Ran  , Li Yong  , Liu Xiao-Chuang  , Zhang Xiao-Ming  , Wang Wen-Hong  , Wu Guang-Heng  , Liu Guo-Dong  ,   School of Material Sciences and Engineering, Hebei University of Technology, Tianjin 300130, China;,   Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
Published: December 2020

The electronic structures of Heusler alloys X2RuPb (X=Lu, Y) under different conditions are investigated using the first-principles calculations. It is found that the alloys become the real topological insulators under a proper lattice deformation or doping. The spin-orbital coupling and the interatomic hybridization effect reinforce each other to perform the band inversion in X2RuPb (X=Lu, Y) compounds and they play roles to different degrees for the materials with different compositions. The ideal topological insulators are easier to obtain using simultaneously lattice deformation and doping artifices, which is available in practical material preparation.
Molecular structure and properties of zirconiumdioxide under the external electric field
Authors: Ling Zhi-Gang  , Tang Yan-Lin  , Li Tao  , Li Yu-Peng  , Wei Xiao-Nan  ,   Department of Physics, Guizhou University, Guiyang 550025, China
Published: December 2020

In order to study the influence of external electric field on ZrO2, molecular structure of ZrO2 ground state is optimized by density functional theory (B3P86) method with 6-311++G* basis sets for O atom and aug-cc-pVTZ-PP for Zr atom. The effects of electric field ranging from 0 to 0.025 a.u. are investigated on bond length, total energy, charge distribution, dipole moment, HOMO (the highest occupied molecular orbital) energy level, LUMO (the lowest unoccupied molecular orbital) energy level and energy gap. The excitation energies, transition wavelengths and oscillator strengths under the same intense external electric fields are calculated by the time dependent density functional theory (TD-B3P86) method. The result shows that the bond length of Zr-2O and total energy increase with external field increasing, but the bond lengths of Zr-3O, LUMOs and energy gaps decrease, and HOMOs almost keep the same. The excitation energies decrease and the transition wavelengths of the six excited states are red shifted toward longer wavelength as the applied electric field increases. Therefore the spectral region of zirconiumdioxide molecule can be expanded in visible-infrared region by the use of external electric fields.
Infrared absorption of deuterium molecules at low temperature
Authors: Liu Jiang-Ping  , Li Jun  , Liu Yuan-Qiong  , Lei Hai-Le  , Wei Jian-Jun  ,   Research Centre of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900, China;,   Institute of Atomic and Moleculer Physics, Sichuan University, Chengdu 610065, China
Published: December 2020

The vibration/rotation modes and the corresponding infrared spectra of deuterium molecules with the D2d/D2h structures are calculated using the coupled cluster singles and doubles method with the cc-PVTZ basis sets within the framework of the density function theory. The infrared (IR) absorption spectrum of liquid deuterium is experimentally measured in a home-made cryogenic target system by a home-made low-temperature infrared spectroscope. The experimental results show that the strongest IR absorption peak of liquid deuterium is related to the Q1(0)+S0(0) mode, which is in good agreement with the theoretical calculation.
Laer polarization dependence of double ionization of molecules
Authors: Tong Ai-Hong  , Feng Guo-Qiang  ,   Department of Physics and Mechanical and Electrical Engineering, Hubei University of Education, Wuhan 430205, China
Published: December 2020

Using classical ensemble method, we investigate the laser ellipticity dependence of double ionization (DI) of H2 molecules. The results show that DI mechanism of H2 molecules depends strongly on laser polarization. As the ellipticity increases, the DI mechanism changes from nonsequential DI to sequential DI. For sequential DI in the case of large ellipticity, the momentum distribution of the two electrons depends sensitively on ellipticity, which indicates the sensitive dependence of the release time of two electrons on ellipticity.
Simultaneous demultiplexing into two 10 Gbit/s using a bidirectionally operated highly nonlinear fiber
Authors: Jia Nan  , Li Tang-Jun  , Sun Jian  , Zhong Kang-Ping  , Wang Mu-Guang  ,   Key Laboratory of All Optical Network and Advanced Telecommunication Network of Ministry of Education, Institute of Lightwave Technology, Beijing Jiaotong University, Beijing 100044, China
Published: December 2020

A simultaneous two-channel optical time division multiplexing (OTDM) demultiplexing is proposed and experimentally demonstrated by using a bidirectionally operated highly nonlinear fiber followed by a narrow-band offset filter. The performance of the proposed demultiplexer is evaluated in an 80 Gbit/s OTDM transmission system. A maximum power penalty of 2.6 dB is obtained for the worst demultiplexed channel. The proposal might be interesting since it offers a powerful tool for developing ultrafast photonic networks.
Double-clad large-mode-area polarization-maintaining ytterbium doped photonic crystal fiber
Authors: Zhao Nan  , Chen Gui  , Wang Yi-Bo  , Peng Jing-Gang  , Li Jin-Yan  ,   Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074, China
Published: December 2020

The Yb3+ doped double clad polarization-maintaining photonic crystal fiber is prepared from SiO2-Al2O3-P2O5 core glass of an optical fiber perform through a conventional modified chemical-vapor deposition technique and solution doping method, which contains a large core of around 30 m in diameter. Through simulated calculation, the mode area of the double clad polarization maintaining photonic crystal fiber reaches about 232 m2 and the double refraction coefficient B can be 510-5. In experiment, amplification tests of both pulse laser and continuous laser are conducted. The first domestic high efficient femtosecond laser amplification is achieved by using the photonic crystal fiber. A 2 m long photonic crystal fiber laser generates up to 1.64 W output power with a slope efficiency of 49.8%. And 5 m long fiber can reach 8.12 W continuous laser output, in which the slope efficiency is 55.9% and performs good amplification effect. Besides, the extinction ratio is about 10 dB, which indicates good polarization performance of the fiber.
The two-mode laser stochastic resonance under the first-order approximation
Authors: Zhang Liang-Ying  , Jin Guo-Xiang  , Wang Zhi-Yun  , Cao Li  ,   School of Physics and Electronic Engineering, Hubei University of Arts and Science, Xiangyang 441053, China;,   Hubei Province Key Laboratory of Intelligent Robot, Wuhan Institute of Technology, Wuhan 430073, China;,   School of Physics, Huazhong University of Science and Technology, Wuhan 430074, China
Published: December 2020

By adding periodic signal into two-mode laser, we take the first-order approximation to the multiplication noise of the laser intensity equation, and use a linear approximation to calculate the correlated function and power spectrum. We find that the signal-to-noise ratio presents stochastic resonance as the intensities of pump noise and quantum noise and the frequency of signal vary.
Cylindrical macroporous silica inverse opal structures coassembled by sol-gel assembly method
Authors: Li Xia  , Guo Wen-Hua  , Lü Zhi-Juan  , Xing Jin-Hua  , Wang Ming  ,   Jiangsu Laboratory of Advanced Functional Materials, Department of Opto-Electronic Engineering, Changshu Institute of Technology, Changshu 215500, China;,   Key Laboratory on Opto-Electronic Technology of Jiangsu Province, School of Physics and Technology, Nanjing Normal University, Nanjing 210097, China
Published: December 2020

Cylindrical macroporous silica structures are fabricated on the surfaces of glass capillary with different diameters by a sol-gel cooperative assembly method. The cylindrical inverse opals are characterized by scanning electron microscope, showing that the (111)-like plane of face-centered-cubic (fcc) structure is parallel to the surface of the cylindrical capillary. Transmission spectra demonstrate typical photonic band gaps (PBGs) of about 40% in the direction of [111] lattice orientation, which accords well with the result from the Bragg formula. The excellent optical properties not only affirm the success of sol-gel coassembled macroporous silica inverse opals on cylindrical substrates, but also introduce PBG materials to meet the requirements of the practical applications of optical communication, optical switching and sensors.
Phononic crystal multi-channel low-frequency filter based on locally resonant unit
Authors: Cheng Cong  , Wu Fu-Gen  , Zhang Xin  , Yao Yuan-Wei  ,   Department of Experiment Education, Guangdong University of Technology, Guangzhou 510006, China;,   Department of Physics and Optoelectronic Engineering, Guangdong University of Technology, Guangzhou 510006, China
Published: December 2020

In this pager, we theoretically propose a model for low-frequency multi-channel filtering of phononic crystal composed of locally resonant units By introducing the resonance units with different filling rates into two-dimensional three-component locally resonant phononic crystal, a waveguide is built Its band structure transmission curve and transmitted sound pressure field map are calculated by the finite element method This design results in a low frequency range of the band gap emergence of new discrete mode around the different resonant frequencies of the scatterer These discrete modes enable the corresponding sound wave to propagate along the waveguide direction in phononic crystal waveguide The discrete model is only associated with the respective resonant unit, so it has a strong anti-jamming capability It provides a new theoretical basis for the multi-channel low-frequency filter.
Analyses of ionization radiation damage and dose rate effect of bipolar voltage comparator
Authors: Ma Wu-Ying  , Lu Wu  , Guo Qi  , He Cheng-Fa  , Wu Xue  , Wang Xin  , Cong Zhong-Chao  , Wang Bo  , Maria  ,   Key Laboratory of Functional Materials and Devices for Special Environments of CAS, Xinjiang Key Laboratory of Electronic Information Materials and Devices, Xinjiang Technical Institute of Physics and Chemistry of CAS, Urumqi 830011, China;,   University of Chinese Academy of Sciences, Beijing 100049, China
Published: December 2020

In order to investigate the dose rate effect and the radiation response of the voltage comparator, a group of bipolar voltage comparators are irradiated by 60Co at high-and low-dose rates under different bias conditions. The results show that many of the parameters for the voltage comparator subjected to ionization radiation, such as power current, input bias current, input offset voltage, and output voltage, are degraded to a certain extent; the irradiation response of the voltage comparator is severely affected by bias condition. What is more, the same type of circuits manufactured from different companies exhibit different dose rate effects; the reasons for the degradation are discussed by analyzing the experiment results. The mechanism for the formation of dose rate effect is also analyzed from the annealing characteristics. The results obtained in this paper are not only useful for the applications of the radiation hardness device, but also helpful for its design.
Sound velocities of vanadium under shock compression
Authors: Yu Yu-Ying  , Tan Ye  , Dai Cheng-Da  , Li Xue-Mei  , Li Ying-Hua  , Tan Hua  ,   National Key Laboratory of Shock Waves and Detonation Physics, Institute of Fluid Physics, Chinese Academy of Engineering Physics, Mianyang 621900, China
Published: December 2020

A series of reverse-impact experiments is performed on vanadium at peak shock pressures from 32 GPa to 88 GPa. A displacement interferometer is used to measure the particle velocity profile at the vanadium/LiF window interface. Analysis of these profile provides a measure of sound velocity of vanadium in the Hugoniot state. The transition from body-centered cubic structure to rhombohedral structure phase at ～ 60 GPa is identified by the discontinuity of the sound velocity against shock pressure. This transition pressure is consistent with the data from high pressure diamond anvil cell experiments and first-principle calculations.
Growth of micro-devices of topological insulator thin films by molecular beam epitaxy on substrates pre-patterned with photolithography
Authors: Wei Pang  , Li Kang  , Feng Xiao  , Ou Yun-Bo  , Zhang Li-Guo  , Wang Li-Li  , He Ke  , Ma Xu-Cun  , Xue Qi-Kun  ,   School of Electronic Engineering, Beijing University of Posts and Telecommunications, Beijing 100876, China;,   Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China;,   State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China
Published: December 2020

In the fabrication of micrometer-sized structures from an epitaxial topological insulator thin film with photolithography, the film is usually deteriorated by the chemicals used in the process. By molecular beam epitaxy of (BixSb1-x)2Te3 topological insulator onto Hall bar-shaped plateaus pre-lithographed on SrTiO3 substrate, we have directly prepared Hall bar devices of epitaxial topological insulator thin film, avoiding the degradation of film quality in photolithography. Atomic force microscope and transport measurements have demonstrated that the Hall bar devices have the similar properties as that of (BixSb1-x)2Te3 films epitaxied on ordinary SrTiO3 substrates. The new microfabrication method can not only help to realize various novel quantum phenomena predicted in topological insulators but be applied to other epitaxial low-dimensional systems as well.
Electrophoresis-assisted fabrication of pseudo 1-3 ceramic/polymer piezoelectric composites
Authors: Wu Zheng  , Zhou Jia-Yi  , Cao Yi  , Ma Ke  , Jia Yan-Min  , Zhang Yi-He  ,   Department of Physics and College of Geography and Environmental Sciences, Zhejiang Normal University, Jinhua 321004, China;,   School of Materials Science and Technology, China University of Geosciences, Beijing 100083, China
Published: December 2020

The 1-3 ceramic/polymer piezoelectric composites have greater dielectric, piezoelectric and ferroelectric properties than 0-3 composites. In this paper, electrophoresis is introduced into the fabrication procedure of traditional 0-3 ceramic/polymer piezoelectric composite to move and pearl-serially align the piezoelectric particles in the polymer matrix, which is called pseudo 1-3 composite. In this work, the PZT/epoxy pseudo 1-3 piezoelectric is fabricated via using a 500 V/mm, 4 kHz AC electric field to form the electrophoresis phenomenon during the curing procedure. Compared with the traditional 0-3 piezoelectric composites, the pseudo 1-3 piezoelectric composites behave as the significantly-enhanced dielectric, piezoelectric and ferroelectric performances on basis of our theoretical analysis and experimental measurement result. Electrophoresis–assisted fabricating pseudo 1-3 piezoelectric composite possesses the advantages of simple operation, low cost and significant performance improvement, which make it hopeful to be used to prepare high-performance ceramic/polymer piezoelectric composites for practical application.
Active tunable metamaterial transmission line based on lumped elements and negative differencial devices
Authors: Si Li-Ming  , Hou Ji-Xuan  , Liu Yong  , Lü Xin  ,   Beijing Key Laboratory of Millimeter Wave and Terahertz Technology, Department of Electronic Engineering, School of Information and Electronics, Beijing Institute of Technology, Beijing 100081, China;,   Department of Physics, Southeast University, Nanjing 211189, China
Published: December 2020

To overcome the defects of metamaterials, such as high dispersion, the high loss, and the problem of homogenization, we design and implement an active tunable metamaterial transmission line, and measure the characteristics of active tunable metamaterial transmission line that is based on lumped elements and negative differential devices. From the measured results, it exhibits not only electronically tunable scattering parameters (electro-control tunable characteristic) but also the negative attenuation constant (the propagation amplification) in the left-handed frequency band (active characteristic).
Identification for hole transporting properties of NPB based on particle swarm optimization algorithm
Authors: Liu Rui-Lan  , Wang Xu-Liang  , Tang Chao  ,   College of Automation, Nanjing University of Posts and Telecommunications, Nanjing 210036, China;,   College of Material Science and Engineering, Nanjing University of Posts and Telecommunications, Nanjing 210036, China
Published: December 2020

In order to study the carrier transporting properties in organic semiconductors (OSCs), the samples of single layer structure ITO/NPB/Ag are prepared, and the corresponding admittance model in theory is built. Impedance samples of the structure under different DC bias voltages are obtained by small sinusoidal signal frequency test method. The particle swarm optimization (PSO) algorithm, in which fitness function includes both the real part and the imaginary part of OSC impedance, is used to identify the model parameter including dispersion coefficient M, α and charge-carrier transit time τdc. To validate the proposed method, an equivalent circuit model of the structure, whose time constant τc is identified by least squares method, is built. Two single-layer structures, whose NPB thickness values are respectively 1000 nm and 1200 nm, are tested. Test results show that the charge-carrier transit time τdc is proportional to the time constant τc and the two hole mobility μdc values both satisfy the famous Poole-Frenkel formula.
Optimization design of hydrogenated amorphous silicon germanium thin film solar cell with graded band gap profile
Authors: Ke Shao-Ying  , Wang Chong  , Pan Tao  , He Peng  , Yang Jie  , Yang Yu  ,   Institute of Optoelectronic Information Materials, Yunnan University, Kunming 650091, China
Published: December 2020

The simulation program AMPS-1D (analysis of microelectronic and photonic structures) employed to simulate and compare the performances of hydrogenated amorphous silicon germanium (a-SiGe:H) thin film solar cell with and without band gap grading at a radiation of AM1.5G (100 mW/cm2) and room temperature by introducing energy band engineering. The simulation results show that the efficiency of the solar cell with band gap grading is 0.477% higher than that without band gap grading due to the higher open circuit voltage (Voc) and better fill factor (FF). Subsequently, a-SiGe:H thin film solar cells with three different window layers such as hydrogenated amorphous silicon (a-Si:H), hydrogenated amorphous silicon carbide (a-SiC:H) and hydrogenated nanocrystalline silicon (nc-Si:H) are simulated, respectively. The numeric calculation results indicate that the fermi level EF of the a-SiGe:H thin film solar cell crosses the valence band when nc-Si:H window layer is employed in the simulation. This will improve the conductivity and the open circuit voltage of the solar cell. In addition, the electric field at front contact interface is reduced due to the lower contact barrier height. This may be more beneficial to the carrier collection by front contact. On the other hand, thanks to the wider band-gap difference between the window layer and the intrinsic layer, a potential barrier is built at the valence-band p/i interface due to the band offset. This will hinder the hole migration and collection. Thus, an nc-Si:H buffer layer, which can relax the valence-band offset and be more beneficial to the carrier migration and collection, is introduced at p/i interface. Finally, the optimum conversion efficiency of the a-SiGe:H thin film solar cell with graded band gap is achieved to be 9.104%.
Study on light-induced degradation of silicon wafers and solar cells
Authors: Zeng Xiang-An  , Ai Bin  , Deng You-Jun  , Shen Hui  ,   Institute for Solar Energy Systems, School of Physics and Engineering, Sun Yat-sen University, Guangzhou 510275, China
Published: December 2020

In this paper, the laws of light-induced degradation (LID) in silicon wafers and solar cells are investigated by using xenon lamp as light source. There are tested 15 types of the silicon wafers contain the including primary wafer, chemical thinned wafer, thermal oxidation passivation wafer, passivation SiNx:H wafer deposited by plasma enhanced chemical vapor deposition, iodine passivation wafers of three different types of silicons: B-doped CZ-Silicon, B-doped Multicrystalline (MC) silicon, and B-doped Upgraded-Metallurgical-grade (UMG) silicon. There are tested 3 types of silicon solar cells: CZ solar cell, MC solar cell, and UMG solar cell. The light intensity is 1000 W/m2 in test. By using WT-2000 tester and solar cells I-V tester, the variations of minority carrier lifetimes of silicon wafers and the I-V characteristic parameters of solar cells with time of light exposure are tested and recorded. Finally the law of LID is found. Under our light condition (light source is a xenon lamp with a light intensity of 1000 W/m2), all kinds of silicon wafers and solar cells are degraded rapidly within the first 60 min, then slowly until the 180 min, finally the rate tends to 0. The LID becomes very slight after 180 min lighting.
A pervasive optimized algorithm for complex network routing strategy
Authors: Li Shi-Bao  , Lou Lin-Lin  , Chen Rui-Xiang  , Hong Li  ,   College of Computer and Communication Engineering, China University Of Petroleum, Qingdao 266580, China
Published: December 2020

There are many existing routing strategies in complex networks, but there is no uniform standard to measure whether the strategies achieve optimal transmission effect. A pervasive optimized algorithm is proposed. The key factor restricting transmission capacity is maximum betweenness centrality and minimizing it becomes the uniform standard. In order to make betweenness centrality more evenly distributed and balance the traffic load of each node, we use punishment selection method to avoid the nodes with larger betweenness centrality. The simulation results show that the new algorithm could reduce maximum betweenness centrality of existing strategies and improve the network transmittability greatly.
Research on robustness of interdependent network for suppressing cascading failure
Authors: Chen Shi-Ming  , Zou Xiao-Qun  , Lü Hui  , Xu Qing-Gang  ,   School of Electrical and Electronic Engineering, East China Jiaotong University, Nanchang 330013, China
Published: December 2020

In order to study the influences of network coupling strength, subnetwork edge, and coupling edge of interdependent networks on the network robustness, symmetrically and asymmetrically coupled interdependent network models are constructed based on three typical network models. Firstly, we calculate the cost thresholds of six different interdependent networks, and find that the coupling edges have a greater influence on the cost of interdependent network than the edges of sub-networks. Furthermore, the relationship of the two parameters (α, β) with the cost of network is obtained by simulation and theoretical analysis, and the cost of network correlated with the two parameters is proved. Finally, by setting the cost of network as a variable measuring the robustness, the simulations on interdependent networks for suppressing cascading failure provide the values of the parameters corresponding to the strongest robustness and the relationship between the robustness and the coupling strength, and it is found that the robustness of network neither increases nor decreases monotonically with the increase coupling strength.
The theoretical study of the turning period in numerical weather prediction models based on the Lorenz equations
Authors: Da Chao-Jiu  , Mu Shuai  , Ma De-Shan  , Yu Hai-Peng  , Hou Wei  , Gong Zhi-Qiang  ,   School of Mathematics and Computer Science Institute, Northwest University for Nationalities, Lanzhou 730030, China;,   College of Atmospheric Sciences, Lanzhou University, Lanzhou 730000, China;,   Laboratory for Climate Studies, National Climate Center, China Meteorological Administration, Beijing 100081, China
Published: December 2020

Based on the Lorenz equations, the dynamics of the weather turning period is studied about numerical weather prediction. Through the analysis of the stability of equilibrium points of the Lorenz equations, we get the surfaces which separate the quasi-stable region and quasi-unstable region. In the quasi-stable region, the path curve of the Lorenz equations can remain relatively stable around the equilibrium points, however in the quasi-unstable region, the path curve of the Lorenz equations can spring from this equilibrium point to another one. This is one of the important dynamic characteristics of the Lorenz system, and the paper give new method and theory for the detection of the abrupt change of climate.
Characteristics of information transfer of interaction between Mid and low-latitudes atmosphere
Authors: Zhang Zhi-Sen  , Feng Guo-Lin  , Gong Zhi-Qiang  , Wu Hao  ,   Department of Atmospheric and Sciences Lanzhou University, Lanzhou 730000, China;,   Laboratory for Climate Studies, Beijing 100081, China
Published: December 2020

In this article, information source characteristic degree, information sink characteristic degree and transfer equilibrium characteristic degree are defined based on transfer entropy. According to the definition, the information transfer in air-sea interaction is examined with sea surface temperature (SST) and geopotential height (GH). And the information transfer between central and eastern equatorial Pacific (20°S–20°N, 170°E–100°W) and tropics (20°S–20°N), and that between atmospheres in high latitude regions of northern hemisphere (north of 20°N) and southern hemisphere (south of 20°S) are analyzed too. In addition, decadal changes and seasonal differences in information transfer between central and eastern equatorial Pacific ocean and atmosphere are discussed by the defined indices of SST and HG. In a word, the information source distribution of ocean is mainly in tropics and the information sink distribution of atmosphere is mainly in mid-latitude. From the low-latitude to the mid-latitude, the ocean forcing the atmosphere is weakened while the atmosphere forcing the ocean is strengthened. Significant regional difference, decadal change and seasonal difference exist in information transfer from the tropical ocean to the atmosphere.
Research on microphysical property of raindrops based on particle imaging velocimetry technology
Authors: Liu Xi-Chuan  , Gao Tai-Chang  , Liu Lei  , Zhai Dong-Li  ,   College of Meteorology and Oceanography, PLA University of Science and Technology, Nanjing 211101, China;,   Ying EnTe Environment Technique Co.LTD, Nanjing 211101, China
Published: December 2020

In order to obtain the shapes, sizes, fall velocities, orientations of raindrops in the natural condition, starting from the particle imaging velocimetry transient visual measurement technology, an image restoration algorithm based on point spread function and a velocity calculation algorithm based on auto-correlation image are investigated, and a natural precipitation imaging velocimetry system based on a CCD sensor is designed and developed in this paper. The diameters, terminal velocities, axis ratios, orientations and their distributions of raindrops are investigated by the field experiment. The velocities of raindrops increase exponentially with the diameter, and axis ratios of raindrops decrease linearly with the diameter, the orientations of raindrops are easily affected by the wind, the average canting angle for all drops tends to be nearly symmetric 2.1° with a standard deviation of 11.5°. The empirical relations between velocity and diameter, between axis ratio and diameter are fitted by nonlinear fitting and linear fitting of observed data. In this paper we further provide microphysical characteristics of raindrops with local features. compared with those from the existing model. These conclusions are of important significance for the research on cloud precipitation physics, ground calibration of weather radar, assessment of rain induced microwave attenuation, etc.
Quantum discord in the system of atoms interacting with coupled cavities
Authors: Li Rui-Qi  , Lu Dao-Ming  ,   College of Mechanic and Electronic Engineering, Wuyi University, Wuyishan 354300, China
Published: December 2020

The geometrical quantum discord (GQD) is an effective measure of quantum correlation in quantum systems. We have studied GQD dynamics of the system comprising two two-level atoms resonantly interacting with two coupled cavities. GQD between atoms and that between cavities are investigated. The influences of coupling constant between cavities and initial entanglement between atoms on GQD are discussed. Results obtained using a numerical method show that GQD between atoms is strengthened, and GQD between cavities is weakened with increasing initial entanglement between atoms. On the other hand, the evolution regularity of GQD between atoms and that between cavities are all strengthened with increasing coupling constant between cavities.