bluuebunny/crossref_metadata_2025 huggingface dataset:
First-principle study on optoelectronic and magnetic properties of Sn(O1-xNx)2
Authors: Zhang Guo-Lian  , Lu Yao  , Jiang Lei  , Wang Zhe  , Zhang Chang-Wen  , Wang Pei-Ji  ,   School of Physics, University of Jinan, Jinan 250022, China
Published: December 2020

Optoelectronic and magnetic properties for Sn(O1-xNx)2 material were examined using quantum chemical ab initio calculation software WIEN2K based on the first principles of density functional theory. The density of states, the band structure, the magnetism, dielectric function and the refractive index are analyzed. The results show that the band gap frist narrowed and then increases with the increase of doping concentration of nitrogen substituting oxygen, the band gap of Sn(O1-xNx)2 becomes the narrowest when the concentration of nitrogen is 12.50%. As a result of the contribution of the electron of N 2p orbit, a low acceptor level appears in a range of 0.551.05 eV, and the level spliting and the orbit overlap appear in the valence band and conduction band. The SnO bond is stronger than the NO bond. From the magnetism, the magnetic moment is determined by N atoms. We know that the optical absorption edge is widened from the imaginary part of dielectric function. The main transition peak is red shifted and the refractive index is corresponding to the dielectric function related to the transition of electrons.
First-principles study of (InAs)1/(GaSb)1 superlattice nanowires
Authors: Sun Wei-Feng  , Zheng Xiao-Xia  ,   Key Laboratory of Engineering Dielectrics and Its Application, Ministry of Education, Heilongjiang Provincial Key Laboratory of Dielectric Engineering, School of Electrical and Electronic Engineering, Harbin University of Science and Technology, Harbin 150080, China;,   Department of Computer Science and Technology, Heilongjiang Institute of Technology, Harbin 150050, China
Published: December 2020

As the active areas and the connection part, semiconductor nanowires have ideal shapes which are beneficial to restricting the electron motion and atomic periodicity to one one-dimensional structure. The effective selection of material components in nanowires can enhance the advantages of low-dimensional structures by analyzing the features of bulk materials. Furthermore, the nanowire properties can also be tailored by controlling the internal or intrinsic characteristics such as diameters, crystallographic growth direction, structural phase, surface crystallographic plane or saturation degree, and by applying external influences such as electric, magnetic, thermal and force fields. The bulk InAs and GaSb have approximate lattice constants, thereby resulting in small lattice mismatch for InAs/GaSb heterostructures that can finally be grown into excellent infrared optoelectronic materials. Moreover, the bulk InAs has the lowest electron effective mass in binary III-V compound semiconductors, leading to high transport features for electrons distributing most in InAs layers of InAs/GaSb superlattices. In the present work, the zinc-blend (InAs)1/(GaSb)1 superlattice nanowires (subscript denotes the number of molecular or double-atomic layers) with [001] and [111] crystallographic wire-axes have been studied by first-principles calculations for their structural, electronic and mechanical properties together with the rule of different nanowire diameters (from ～0.5 to ～2.0 nm). We also analyze the stress effects from external forces and examine the electronic band-edge changes with strain in wire-axis direction to determine the deformation potentials.
Effects of Al2O3 on micro-structure and crystallization of oxyfluoride glass
Authors: Liu Min  , Yu Hua  , Zhang Pan  , Zhang Ming  , Liu Yan  , Zhao Li-Juan  ,   Key Laboratory of Weak Light Nonlinear Photonics, Ministry of Education, School of Physics, Nankai University, Tianjin 300457, China
Published: December 2020

The effects of Al2O3 on micro-structure and crystallization of oxyfluoride glass are investigated by infrared spectra, Raman spectra and X-ray diffraction analyses. The results show that [AlO4] is connected with [SiO4] units by means of angle connection, thereby forming the basic network of glass. When the content of Al2O3 increases, the structures of monomer and dimer increase in oxide glass matrix. Under the condition, the size of nanocrystals has a minimum value, while the structure of nancrystals is not affected.
A novel method to configure the parameters of the bilateral filtering for synthetic aperture radar images speckle reduction
Authors: Li Jin-Cai  , Huang Si-Xun  , Peng Yu-Xing  , Zhang Wei-Min  ,   School of Computer Science, National University of Defense Technology, Changsha 410073, China;,   Institute of Meteorology, People's Liberation Army University of Science and Technology, Nanjing 211101, China
Published: December 2020

Bilateral filtering can effectively smooth SAR images with the edges preserved, but it is difficult to optimally configure the parameters of bilateral filtering. Traditional method is based on an optimal trade-off hypothesis according to the despeckling estimation indexes, including the equivalent number of looks (ENL) and edge preserving index (EPI). However, the variance of gray value similarity obtained by traditional method has large error, and to improve accuracy, the computing time is increased linearly. In this paper, we present a novel method to configure the parameters of bilateral filtering based on the hypothesis and the monotone properties of the ENL and EPI curves. Experimental results show that the accuracy of variance of gray value similarity is increased by one order of magnitude in the case of almost the same computing time; the computing time is reduced by one order of magnitude for the same accuracy of variance of gray value similarity.
Theoretical and experimental study of emission spectrum of the second positive system of N2
Authors: Zhai Xiao-Dong  , Ding Yan-Jun  , Peng Zhi-Min  , Luo Rui  ,   State Key Laboratory of Power Systems, Dept of Thermal Engineering, Tsinghua University, Beijing 100084, China
Published: December 2020

The optical emission spectrum of the second positive system of N2(C3uB3g)isanalyzed and calculated based on the energy structure of nitrogen radical triplet system. Some key parameters of the equation for the radiative transition intensity are evaluated theoretically, including the potentials of the upper and lower states obtained from diagonalizing their Hamiltonian matrices, the electronic transition moments calculated by using r-centroid approximation, and the Einstein coefficients of different vib-rotational levels. For comparing with the theoretical spectrum, we achieve the measured results from corona discharge experiments of N2 and Ar. By fitting the measured spectral intensities and the calculated ones, the vibrational and the rotational temperatures are determined approximately to be 4300 K and 800 K. The results also demonstrate that with the reduction of nitrogen concentration, the intensity of N2 radiative state first increases and then decreases due to Penning excitation from argon metastable states. The experimental results verify the correctness of the theoretical calculations on the second positive system.
Study of the satellite line in measurement of the argon -gas-induced broadening of the barium Rydberg levels by two-photon resonant nondegenerate four-wave mixing
Authors: Sun Jiang  , Liu Peng  , Sun Juan  , Su Hong-Xin  , Wang Ying  ,   College of Physical Science and Technology, Hebei University, Baoding 071002, China;,   College of Mathematics and Computer Science, Hebei University, Baodin, 071002, China
Published: December 2020

We study the satellite lines in measurement of the foreign-gas-induced broadening of the barium Rydberg levels by two-photon resonant nondegenerate four-wave mixing (NFWM). The NFWM spectra of the 6s2 1S0-6snd 1D2 (n=16, 22, 36) transitions at different argon pressures are measured. The plots of the center of satellite line principal quantum number and versus pressure are discussed. The contribution of satellite line to the NFWM spectral profile is analyzed. We find that the pressure-broadening rate coefficient can be corrected when the contribution of satellite line is considered.
Analysis of Interfacial Mechanical Properties of Carbon NanotubePolymer Composite
Authors: Zhang Zhong-Qiang  , Ding Jian-Ning  , Liu Zhen  , Xue Yi-Bin  , Cheng Guang-Gui  , Ling Zhi-Yong  ,   Micro/Nano Science and Technology Center, Jiangsu University, Zhenjiang 212013, China;,   School of Naval Architecture and Ocean Engineering, Jiangsu University of Science and Technology, Zhenjiang 212003, China;,   Department of Mechanical and Aerospace Engineering, Utah State University, Logan, UT 84322
Published: December 2020

In this paper, the interfacial mechanical properties of carbon nanotube-polyethylene (CNT-PE) composite are investigated by using classical molecular dynamics simulation. Basd on the simulations for the CNT pulling-out process from the PE, the influences of the CNT sliding velocity, the chain length of PE and the radius of CNT on the interfacial shear stress are explored. As the chain length of PE increases, the critical interfacial shear stress increases remarkably while the sliding shear stress increases slightly. Both the critical shear stress and the sliding shear stress increase with the radius of CNT enlarging. Moreover, the mechanism for the variation of interfacial shear stress is analyzed and discussed.
First-principles calculation of matal and nonmetal codoped anantase TiO2
Authors: Peng Li-Ping  , Xia Zheng-Cai  , Yang Chang-Quan  ,   School of Physics, Huazhong University Science and Technology, Wuhan 430074, China;,   School of Physica Science and Technology, Huanggang Normal University, Huanggang 438000, China;,   National High Magnetic Field Center, Huazhong University Science and Technology, Wuhan 430074, China
Published: December 2020

We present a first-principles calculation study of matal and nonmetal codoped anatase TiO2. We mainly investigate C/TM and N/TM (carbon and metal codoped, nitrogen and metal codoped) codoped TiO2, are calculate their bound energies, energy band structures and densities of states. We find that the metal and the nonmetal impurities have an aggregate tendenty by calculating the bound energy of codoping structure. Positive bound energy show that the doping atom and the peripheral atom will combine into a bond, the boding-effect-produced system energy is higher than the geometric-distortion-effect produced stress energy. We analyze the energy band structure and boding of N/V and C/Cr --codoped TiO2, and further find that if we want to extend TiO2 light absorb edge and improve TiO2 photocatalysis properties by metal and nonmetal codoped TiO2, we should make codoping by the codoped joint method, namely, below the conduction band and on the top of valence band can arise impurity energy levels contributed by metal 3d and nonmetal 2p orbits respectively
One-dimensional spinless fermions in a confined system
Authors: Wang Chan-Juan  , Chen A-Hai  , Gao Xian-Long  ,   Department of Physics, Zhejiang Normal University, Jinhua 321004, China
Published: December 2020

According to the exact analytical Bethe-ansatz solution of the one-dimensional spin-1/2 XXZ model, we perform a numerical study of one-dimensional spinless fermions in an optical lattice in the presence of harmonic potential by using a local density approximation. We study the density profile, and obtain the -u phase diagram (here =NfV2/t is the characteristic dimensionless density and u=V/t is the interaction strength scaled in units of the hopping parameter t). With the increases of particle density and nearest-neighbour interaction, the system undergoes five different quantum phases. Through calculating the thermodynamic stiffness S, we find that it can be used as an order parameter. Its singular points can measure the quantum phase transitions in such a confined system.
Investigation of vibronic structures of optical centres in diamond by photoluminescence spectra
Authors: Wang Kai-Yue  , Li Zhi-Hong  , Zhang Bo  , Zhu Yu-Mei  ,   Key Laboratory of Advanced Ceramics and Machining Technology of Ministry of Education, School of Materials Science and Engineering, Tianjin University, Tianjin 300072, China;,   Department of Physics, University of Bristol, Bristol BS8 1TL, UK
Published: December 2020

The vibronic spectra mainly depend on the nature of the defects in diamond. The strong sharp local vibronic modes are observed for the interstitial-related centres beyond their phonon cut-off energy (165meV), but not for the vacancy-related centres. The vibronic spectra of these vacancy-related centres show very strong and broad sidebands closely after the zero phonon lines. Further, the vibrations involving only one vacancy are due to two separate phonons or both, one has an energy of approximately 42 meV and the other has approximately 67 meV.
Structural optimization of GaN blue light LED with double layers of photonic crystals
Authors: Gao Hui  , Kong Fan-Min  , Li Kang  , Chen Xin-Lian  , Ding Qing-An  , Sun Jing  ,   School of Information Science and Engineering, Shandong University, Jinan, Shandong 250100, China;,   School of Physics, University of Jinan, Jinan, Shandong 250022, China
Published: December 2020

The GaN-based blue light LED with double layer photonic crystals is designed to enhance the vertical light extraction efficiency. The effective index approximation method is proposed and used to solve the distribution of the modes in the LED model. The geometrical parameters including the depth of the top photonic crystal d, the thickness of the embedded photonic crystal T, and the distance between the active layer and the embedded photonic crystal D are optimized. Compared with other numerical optimization, the mode analysis used in this work can dramatically save computation time and reduce complexity. In addition, it can provide more theoretical details about the influence of these geometrical parameters on light extraction efficiency. It can be found that when the surface photonic crystal satisfies the condition of d / nPhCs, high order modes localized in the structure are still not cut off but the low order modes obtain less power since they are pushed away from the active layer. Hence, the light extraction efficiency reaches its maximum. The cap layer modes can be excited by the embedded photonic crystals, when this layer satisfies 100 nm T 300 nm and 100 nm D 200 nm, the cap layer modes gather much power from the active layer and interact with the surface photonic crystals more efficiently. Hence the light extraction efficiency is dramatically improved. With our optimized parameters, the light extraction efficiency can be achieved to be up 4 times that of ordinary LED. These results shows a significant promise of designing a high-efficiency GaN-based blue light LED.
Radiation degradation mechanism of pn-junction diode based on 1/f noise variation
Authors: Sun Peng  , Du Lei  , He Liang  , Chen Wen-Hao  , Liu Yu-Dong  , Zhao Ying  ,   School of Technical Physics, Xidian University, Xi’an 710071, China
Published: December 2020

Based on the relationship between ionizing damage effect and displacement damage effect under radiation degradation mechanism of pn-junction diode, and combined with the noise theory of radiation degradation of pn-junction diode, a change law of low frequency noise of pn-junction diode under radiation found. The inconsistency between the change laws of of two kinds of effects is found. Based on the experimental result, the relationship between two kinds of effects is judged. This relationship can explain the experimental result. This is very important for the device hardening research.
Magnetotelluric joint inversion for anisotropic conductivities in layered media
Authors: Huo Guang-Pu  , Hu Xiang-Yun  , Fang Hui  , Huang Yi-Fan  ,   Institute of Geophysics and Geometics, China University of Geosciences, Wuhan 430074, China;,   Institute of Geophysical and Geochemical Exploration, CAGS, Langfang 065000, China
Published: December 2020

The electrical anisotropy in the crust and the upper mantle is the main link among geoelectrical model, underlying structure, and tectonic model. In recent years, great attention was paid to this phenomenon, which promotes the new research towards the structure model of electrical anisotropy and inversion theory. According to the Marquardt's inversion theory, in the paper we first improve the weighting factor and apply it to the apparent resistivity and impedance phase joint inversion. Then, the detailed example analysis of them proves the corrctness of the mentioned theory. Additionally, the processing and the interpretation of the measured magnetotelluric data in northwest of china not only indicate the practicability of the theory, but also provide a new method for the future research of deep electrical structures.
Simulation of reflection spectrum of FBG with uniaxial anisotropic crystal cladding
Authors: Li Li-Jun  , Ma Hui  , Zhang Yan-Liang  , Sui Tao  , Lai Yong-Zheng  , Li Jing  , Cao Mao-Yong  ,   College of Information and Electrical Engineering, Shandong University of Science and Technology, Qingdao 266590, China
Published: December 2020

In this paper, the ideal normal mode characteristic equation of the optical fiber with uniaxial anisotropic crystal cladding is derived. Using mean value theorem and combining Matlab numerical method, a solving algorithm of this transcendental equation is proposed. Therefore, the relationship between FBG reflect spectrum characteristic and cladding reflective index is simulated. The simulation results show that kcl has a strong influence on the spectrum, different values of kcl can lead to different reflectivities and different Bragg wavelengths.
Molecular dynamics simulation on friction process of silicon-doped diamond-like carbon films
Authors: Lan Hui-Qing  , Xu Cang  ,   School of Mechanical, Electronic and Control Engineering, Beijing Jiaotong University, Beijing 100044, China
Published: December 2020

Silicon-doped diamond-like carbon (Si-DLC) film is of significant interest for tribological effects, because it has a very low friction coefficient and possesses the potential to improve wear performance in humid atmospheres and at high temperatures. Many experimental results of the Si-DLC film show that its tribological property changes greatly with silicon content. In this paper, we use molecular dynamics (MD) simulation to study sliding friction processes between DLC and Si-DLC films under dry friction and oil-lubricated conditions separately. The results show that after sliding, a transfer film between the DLC and Si-DLC films is formed under the dry friction condition. In contrast, a boundary lubrication layer is found under the oil-lubricated condition. Therefore the friction forces on the dry friction condition are larger than those on the oil-lubricated condition. Small addition of silicon atoms can reduce the friction force of DLC films indeed, but it has little effect to the friction force when the silicon content is larger than 20%. There is a obvious effect of the silicon content on the bond number of transfer films under the dry friction condition, and CC bond and CSi bond both first increase and then decrease, there is almost no little CSi bond at the end of the sliding.
Design of a low-frequency broadband metamaterial absorber based on resistance frequency selective surface
Authors: Cheng Yong-Zhi  , Wang Ying  , Nie Yan  , Zheng Dong-Hao  , Gong Rong-Zhou  , Xiong Xuan  , Wang Xian  ,   Department of Electronic Science & Technology, Huazhong University of Science and Technology, Wuhan 430074, China
Published: December 2020

A low-frequency broadband, polarization-insensitive and wide-angle metamaterial absorber is presented, which is based on resistance frequency selective surface (RFSS). The unit cell of this absorber consists of cave cross planar metamaterial (CCPM), RFSS, dielectric substrate and metal backboard. The simulated results based on FDTD method indicate that with the absorptions of compared to the individual CCPM absorber and RFSS absorber, the absorption of the composite structure absorber of CCPM and RFSS is enhanced greatly, and it is greater than 80% and the absorption peak is over 98% in the whole frequency range of 15 GHz. The simulated absorptions under the conditons of different polarization and incident angles indicate that this composite structure absorber has polarization-insensitive and wide-angle absorption.
The study of asymmetric energy transmission based on the nonlinear supratransmission
Authors: Tao Feng  , Chen Wei-Zhong  , Xu Wen  , Du Si-Dan  ,   Institute of Acoustics,Key Laboratory of Modern Acoustics of Ministry of Education, Nanjing University, Nanjing 210093, China;,   School of Electrical Engineering m& Information, Anhui University of Technology, Ma'anshan 243000, China;,   School of Electronic Science and Engineering, Nanjing University, Nanjing 210093, China
Published: December 2020

In this paper, the phenomenon of the asymmetric energy transmission is numerically investigated in the forbidden band of the electrical transmission line formed by two nonlinear segments which are identical in structure but different in inductor parameter. By considering the driving voltage at the frequency within the forbidden bands of both segments, the carrier of the asymmetric energy flux is the nonlinear wave beyond the band, instead of the linear wave in the passband, and the mechanism is closly related to the nonlinear supratransmission. To further understand this phenomenon in electrical transmission line, we also study the correlations between the energy intensity and the circuit parameters. Finally, we investigate the dependency of the voltage threshold on the driving frequency in physical experiment, and the result is qualitatively identical with that calculated by using equation.
Generation and control of electromagnetically induced double photonic band-gaps
Authors: Yu Miao  , Zhang Yan  , Fang Bo  , Gao Jun-Yan  , Gao Jin-Wei  , Wu Jin-Hui  ,   College of Physics, Jilin University, Changchun 130012, China;,   Department of Physics, Harbin Institute of Technology, Harbin 150001, China
Published: December 2020

By using the technique of electromagnetically induced transparency and solving density matrix equations for atoms and transfer matrix equations of fields, we study the steady optical properties of a four-level system of cold atoms driven by a traveling-wave field and a standing-wave field. It is found that a nearly perfect structure of double photonic band-gap can be generated with specific parameters. In particular, the reflectivity inside each photonic band-gap is homogeneous over 95%. It is convenient to modulate the positions and widths of both photonic band-gaps by changing intensities and frequencies of the driving fields. The double photonic band-gaps can be used to achieve all-optical routing and switching and therefore may have applications in all-optical information networks.
Study on characteristics of acoustic modes via stimulated Brillouin scattering in photonic crystal fiber
Authors: Hou Shang-Lin  , Xue Le-Mei  , Li Suo-Ping  , Liu Yan-Jun  , Xu Yong-Zhao  ,   School of Science, Lanzhou University of Technology, Lanzhou 730050, China;,   Institute of Electronic Engineering, Dong Guan University of Technology, Dongguan 523808, China
Published: December 2020

The effects of optical fiber parameters, pump wavelength and the fiber core refractive index in small-core photonic crystal fibers on characteristics of acoustic modes and the dependency of the acoustic modes coupling are investigated by the effective index method. The results indicate that both the mixed longitudinal acoustic mode and transverse acoustic mode jointly produce the acoustic fields, and their coupling forms the mixed acoustic mode; the propagation constant of acoustic mode can be changed by tailoring the pump wavelength or the PCF core refractive index in the process of SBS; the acoustic mode coupling increase and the phase velocity of the acoustic mode decreases with the increase of the PCF core diameter, and there is also a growing trend of the number of the acoustic modes at the same propagation constant. The velocity decreases with the increase of the frequency of the pump wave.
Research on one-dimensional function photonic crystals
Authors: Wang Guang-Huai  , Wang Qing-Cai  , Wu Xiang-Yao  , Zhang Si-Qi  , Wang Jing  , Liu Xiao-Jing  , Ba Nuo  , Gao Hai-Xin  , Guo Yi-Qing  ,   Institute of Physics, Jilin Normal University, Siping 136000, China;,   Institute of High Energy Physics, Chinese Academy of Siences, Beijing 100049, China
Published: December 2020

In the paper, we present a new kind of function photonic crystal of which the refractive index is a function of space position. According to Fermat principle, we give the motion equations of light in one-dimensional, two-dimensional and three-dimensional function photonic crystals. For one-dimensional function photonic crystal, we give the dispersion relation, the band gap structure and the transmissivity, and we obtain wider or narrower band gap structure than that of conventional photonic crystal. We study the effects of the refractive index, the number of period, the incidence angle and the thickness of medium layer on photonic crystal band gap, and obtain some valuable laws. Our results give the theoretical support designing the photonic crystals of different band gap structures.
Laser-driven reservoir target for quasi-isentropic compression in aluminum
Authors: Shan Lian-Qiang  , Gao Yu-Lin  , Xin Jian-Ting  , Wang Feng  , Peng Xiao-Shi  , Xu Tao  , Zhou Wei-Min  , Zhao Zong-Qing  , Cao Lei-Feng  , Wu Yu-Chi  , Zhu Bin  , Liu Hong-Jie  , Liu Dong-Xiao  , Shui Min  , He Ying-Ling  , Zhan Xia-Yu  , Gu Yu-Qiu  ,   Science and Technology on Plasma Physics Laboratory, Laser Fusion Research Center, China Academy of Engineering Physics, Mianyang 621900, China
Published: December 2020

The quasi-isentropic compression of material with high strain rate can be obtained by the ramp wave loading of plasma jet produced by laser-driven reservoir target. The quasi-isentropic compression experiments of aluminum are carried out on the high power laser facility of SG-III prototype. The smooth and continuous speed history of free surface of specimen is recorded with a line-imaging velocity interferometer (VISAR). The peak pressure (60 GPa), the rise time of the load (～ 10 ns) and the strain (～ 108 s-1) are derived by the back-integrating method, and the reverberation of compression wave at the rear surface of the sample is observed.
First-principles study of FeAl(B2) microalloyed with La, Ac, Sc and Y
Authors: Zhao Rong-Da  , Zhu Jing-Chuan  , Liu Yong  , Lai Zhong-Hong  ,   The National Key Laboratory for Precision Hot Forming of Metals, Harbin Institute of Technology, Harbin 150001, China
Published: December 2020

The effects of FeAl(B2) microalloyed with rare earth element (REEs) La, Ac, Sc and Y on structural, elastic and electronic properties are investigated by first-principles calculation based on the density function theory (DFT). The calculation results show that the REEs Y tend to be substituted for Fe site, while La, Ac and Sc tend to be substituted for Al site, and Ac causes the largest lattice distortion. The calculation results of elastic properties show that the ductility of FeAl(B2) is improved by the addition of La, Ac, Sc and Y. The Fe7Al8Sc has better ductility and hardness. The effect of REEs on the performance of alloy is attributed to the variation of hybridization between Fe and Al electrons. The calculation results are in accordance with experimental and theoretical results.
Neural network-based backstepping design for the synchronization of cross-strict feedback hyperchaotic systems with unmatched uncertainties
Authors: Li Hai-Yan  , Hu Yun-An  , Ren Jian-Cun  , Zhu Min  , Liu Liang  ,   Department of Control Engineering, Naval Aeronautical and Astronautical University, Yantai 264001, China
Published: December 2020

For a class of cross-strict feedback hyperchaotic systems with unmatched uncertainties, a multilayer neural network (MNN) based adaptive backstepping design method is proposed. An MNN is introduced to estimate the uncertainties in systems. Sliding mode and adaptive backstepping control are used to deal with the unmatched uncertainties and the MNN approximation errors. If the virtual control coefficients do not pass through zeros, the proposed method guarantees that the synchronization errors of the systems approach zeros. If the virtual control coefficients pass through zeros, the proposed method guarantees that the synchronization errors of the systems are bounded. Numerical simulations are given to demonstrate the efficiency of the proposed control scheme.
Coherent control of the Goos-Hnchen shift in four-level atomic medium
Authors: Su Jia-Ni  , Deng Wen-Wu  , Li Gao-Xiang  ,   College of Physical Science and Technology, Huazhong Normal University, Wuhan 430079, China;,   Institute of Photonics and Photo-Technology, Xianning University, Xianning 437100, China
Published: December 2020

The manipulation of the Goos-Hnchen shifts in the reflected and transmitted light beam through a cavity containing four-level atomic medium is investigated by modifying the dispersion-absorption properties of the intracavity medium. Via two external coherent control fields, the Goos-Hnchen shifts of the reflected and transmitted beam can be easily controlled. It is found that around the transparent region of the medium, the Goos-Hnchen shifts are very sensitive and can be enhanced as compared with strong absorption and amplification.
Phase field crystal model for the effect of colored noise on homogenerous nucleation
Authors: Guo Yao-Lin  , Wang Jin-Cheng  , Wang Zhi-Jun  , Tang Sai  , Zhou Yao-He  ,   State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi'an 710072, China
Published: December 2020

Homogenerous nucleation process induced by the colored noise is simulated by the phase field crystal method. The results indicate that the noise strenghth within a certain range almost has no influence on the parameters of equilibrium thermodynamics of the nucleation system, such as nucleation engergy barrier and size of crtical nucleus; however, it will strongly affect the dynamics of the system. The incubation time of nucleation decreases exponenially with the increase of the noise strength. Further analysis shows that this is attributed to the fact that the colored noise can affect the atom mobility in the nucleation process.
Model and simulation of liquid rocket organic gel spray droplet evaporation
Authors: He Bo  , He Hao-Bo  , Feng Song-Jiang  , Nie Wan-Sheng  ,   Company of Postgraduate Management, the Academy of Equipment, Beijing 101416, China;,   Department of Space Equipment, the Academy of Equipment, Beijing 101416, China
Published: December 2020

Gel propellant has the advantage of controllable flux as liquid propellant and long-term reservation as solid propellant, however, the evaporation and combustion problem of gel spray droplet bores with the gel propellant development and combustor design all the time, and hampers gel propellant practical engineering applications. In this paper, the gel single droplet combustion experiment system is designed and constructed, and then the evaporation and combustion mechanism is explored deeply based on the experimental phenomena of organic gel unsymmetrical dimethylhydrazine (UDMH) single droplet burning in nitrogen tetroxide. The organic gel spray droplet multi-component evaporation model is developed for three different evaporation phases of the gel layer, i.e. the forming, expanding and bursting of the gel layer based on the single droplet evaporation characteristics in experiment, and then the gel single droplet vaporization in high temperature gas phase is numerically simulated and compared with the result of conventional liquid droplet using the elementary model parameters and physic property parameters. The result shows that the gel content on the droplet surface increases slowly at the beginning of evaporation, however it would increase rapidly to a mass fraction of 95% and form the gel layer in a limited time after exceeding a critical evaporation time, which results in surface mass flux dropping to 0 and surface temperature reaching the UDMH boil point rapidly. After the gel layer forming, the droplet radius and surface UDMH vapor mass fraction exhibit oscillation as the swelling-bursting phenomena in experiment. The gel droplet surface temperature holds above the boil point and the mass flux of gel droplet inner boiling evaporation is stronger than the conventional liquid droplet surface steady evaporation which makes the life time of gel droplet much shorter.
A first-principles study of capacity and mechanism of a single titanium atom storing hydrogen
Authors: Lu Jin-Lian  , Cao Jue-Xian  ,   Department of Physics and Institute for Nanophysics and Rare-Earth Luminescence, Xiangtan University, Xiangtan 411105, China
Published: December 2020

Using the density functional theory of first principles, we investigate the binding mechanism of a single transition metal atom-titanium adsorbing hydrogen molecules. We find that a single titanium atom can absorb eight hydrogen molecules. The hydrogen molecules around Ti atom form two symmetrical pyramid-like structures with an average adsorption energy of -0.28 eV. By calculating the orbital energie and the distribution of differential charge density, we analyse the intrinsic physical mechanism of determining adsorption structure, adsorption energy and hydrogen storage capacity. The results show that a 4s electron of a titanium atom transfers to the 3d orbit, which can produce a strong polarization electric field, resulting in polarization of the hydrogen molecules. Therefore, the titanium atom adsorbs hydrogen molecules by electrostatic polarization. Our results will present a guidance for designing high-density hydrogen storage materials.
The effect of the relaxation oscillation frequency of chaotic semiconductor laser on the rate of random sequence
Authors: Xiao Bao-Jin  , Hou Jia-Yin  , Zhang Jian-Zhong  , Xue Lu-Gang  , Wang Yun-Cai  ,   College of Information Engineering, Taiyuan University of Technology, Taiyuan 030024, China;,   College of Physics and Optoelectronics Engineering, Taiyuan University of Technology, Taiyuan 030024, China;,   Key Laboratory of Advanced Transducers and Intelligent Control System, Ministry of Education, Taiyuan 030024, China
Published: December 2020

In this paper, chaotic light generated by semiconductor laser with optical feedback is employed as physical entropy source to generate high-speed random sequence. The relationship between autocorrelation coefficient of chaotic signal and run number of random sequence is analyzed. Based on the analysis, the changes of random sequence run number are further investigated at different ratios between laser relaxation oscillation frequency fr and random sequence generation rate fn. The results show that random sequence run can easily meet the requirement for run test of NIST SP800-22 when the ratio between fr and fn satisfies the equation of fr/fn=(2k+1)/4. When k in the equation is equal to 1, the maximal rate fn=4fr/3 of random sequence is obtained.
A Multi-reference configuration interaction investigation of the X2+and A2 low-lying electronic states of AsO+ isotope ion
Authors: Wang Jie-Min  , Zhang Lei  , Shi De-Heng  , Zhu Zun-Lue  , Sun Jin-Feng  ,   College of Physics & Electronic Information, Luoyang Normal College, Luoyang 471022, China;,   College of Physics & Information Engineering, Henan Normal University, Xinxiang 453007, China
Published: December 2020

The potential energy curves (PECs) of AsO+(X2+) and AsO+(A2) are investigated using the full valence complete active space self-consistent field (CASSCF) method through the highly accurate valence internally contracted multireference configuration interaction approach including Davidson correction (MRCI+Q). In the present calculations, the basis sets for As and O are aug-cc-pV5Z and aug-cc-pV6Z respectively. The spectroscopic parameters of the isotopes 75As16O+ and 75As18O+ are determined. The present values of Re, e, exe, e and Be for 75As16O+ (X2+) are 0.15770 nm, 1091.07 cm-1, 5.02017 cm-1, 0.514826 cm-1 and 0.003123 cm-1, respectively; the present values of Te, Re, e, exe, e and Be for 75As16O+ (A2) are 5.248 eV, 0.16982 nm, 776.848 cm-1, 6.71941 cm-1, 0.443385 cm-1 and 0.003948 cm-1, respectively, which are compared with those reported by previous investigations in the literature. And the comparison shows that excellent agreement exists between the present results and the experimentsal ones. With the PECs of AsO+ (X2+) and AsO+ (A2) determined here, the first 20 vibrational states for each electronic state are determined when the rotational quantum number J equals zero (J =0). For each vibrational state, the vibrational level G(v ), inertial rotation constant Bv and centrifugal distortion constant Dv are evaluated when J=0, which are in good accord ance with the available experimental data.
Multiple scattering of light by mixtures of two different aerosol types
Authors: Wang Hai-Hua  , Sun Xian-Ming  ,   School of Electrical and Electronic Engineering, Shandong University of Technology, Zibo 255049, China
Published: December 2020

If particles are mixed with other type of particles, the light scattering characteristics will be changed. In this paper, the light scattering characteristics of water clouds mixed with black carbon are studied. Based on the Mie theory, the single scattering phase function, the single scattering albedo and the asymmetric parameters of water clouds and black carbon aerosols are computed. The Monte Carlo method for simulating the scattering of mixed particles is given, the methods of sampling particle types, sampling free path length, and the sampling scattering directions based on the Mie phase function are given. The changes of the scattering characteristics for water clouds mixed with black carbon aerosols are studied. Reflected light intensity varying with observation angle is calculated with the light normal incidence, and the plane albedo is computed as a function of incidence angle. The influences of mixing ratio and effective radius of black carbon on the scattering characteristic of mixture are discussed. The results show that the black carbon can greatly increase the absorption of the clouds, and the ratio and the size of black aerosols can greatly affect the scattering characteristics of the mixture.
High power all-normal-dispersion mode-locked Yb3+-doped double-clad fiber femtosecond laser
Authors: Liu Hua-Gang  , Huang Jian-Hong  , Weng Wen  , Li Jin-Hui  , Zheng Hui  , Dai Shu-Tao  , Zhao Xian  , Wang Ji-Yang  , Lin Wen-Xiong  ,   Key Laboratory of Optoelectronic Materials Chemistry and Physics, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 35002, China;,   Institute of Crystal Materials, Shandong University, Ji'nan 250100, China
Published: December 2020

A stable all-normal-dispersion dissipative-soliton mode-locked laser is demonstrated with a Yb3+-doped large-mode-area double-clad gain fiber, and nonlinear polarization evolution and spectral filtering composed of a grating and an aperture are exploited to produce sufficient amplitude modulation to shape pulses of this laser. The laser generates chirped pulses at a 76.6 MHz repetition rate, with an average power of 6.3 W, and a single pulse energy of 82 nJ. Pulse duration of the direct output pulse is 1.33 ps and it can be dechirped to 377 fs after externally compressed. By adjusting the grating, the central wavelength of the output pulses can also be tuned from 1025 nm to 1078 nm.
Bohm criterion for a collisinal electronegative plasma sheath in an oblique magnetic field
Authors: Qiu Ming-Hui  , Liu Hui-Ping  , Zou Xiu  ,   School of Science, Dalian Jiaotong University, Dalian 116028, China
Published: December 2020

The Bohm criterion for a collisinal electronegative plasma sheath in an oblique magnetic field is investigated with a fluid model. The effects of negative ions and magnetic field on the Bohm criterion are discussed. It is shown that the parameters of the negative ions affect only the lower limit for Bohm criterion, and the external magnetic field can affect the whole range of the ion Mach number values.
Modeling and simulation of electrification of wind-blown-sand two-phase flow
Authors: Wei Wei  , Lu Lu-Yi  , Gu Zhao-Lin  ,   School of Human Settlements and Civil Engineering, Xi'an Jiaotong University, Xi'an 710049, China;,   School of Energy and Power Engineering, Huangzhong University of Science and Technology, Wuhan 430074, China
Published: December 2020

The electrification of wind-blown sand, such as dust storms and dust devils, is known as the tribo-electric effect of sand particles and the stratification of different size particles. Combined with the grain electrification model, a new numerical method of gas-solid two-phase flow is developed for the simulation of wind-blown-sand two-phase flow, which is a hybrid method of computational fluid dynamics and discrete element method (CFD-DEM). In the developed wind-blown-sand two-phase flow of horizontal wind tunnel, the simulation results indicate that large size grains become positively charged while small size grains become negatively charged, and the critical diameter of grain with electric neutrality is about 300μm. The simulated charge-to-mass ratio and electric field intensity of the wind-blown sands in the field wind tunnel approach to the measured data, showing the rationality of this numerical method. The simulation also demonstrates that there occurs the maximum of electric field intensity over the sand bed of the field wind tunnel, which is the reason why the electric grounding of the field wind tunnel is used in experiment. The coupling of grain electrification model and gas-solid two-phase flow method provides an important tool for interpreting laboratory and field observations of wind-blown sands and insights into the physical dynamics of dust storms and dust devils as well.
Sliding mode tracking synchronization of an uncertain complex network
Authors: Liu Shuang  , Lü Ling  , Li Gang  ,   College of Physics and Electronic Technology, Liaoning Normal University, Dalian 116029, China
Published: December 2020

The problem of tracking synchronization for an uncertain complex network is proposed. By selecting an appropriate sliding surface, designing parameter identification laws and sliding mode controllers, the tracking synchronization between the network and output signal is achieved. The simulation results show that all the state variables in the network can track target orbit strictly, which shows that the method is effective.
Thermodynamic analyses of dewetting instability in thin films
Authors: Wei Qi  , E Wen-Ji  ,   School of Physics Science and Technology, Soochow University, Suzhou 215006, China
Published: December 2020

The dewetting instabilities in thin films under the boundary slip condition are studied using the thermodynamic approach. The general form of characteristic dewetting length scale is obtained from. The dewetting instability in thin film without Marangoni effect and that with Marangoni effect are compared.
The design of tank coating based on photonic crystal
Authors: Li Wen-Sheng  , Luo Shi-Jun  , Huang Hai-Ming  , Zhang Qin  , Fu Yan-Hua  ,   Department of Basic Science, Hubei University of Automotive Technology, Shiyan 442002, China
Published: December 2020

In order to reduce the infrared radiation of tank in actual combat, characteristics of tank barrel radiation after low speed firing are analyzed. Common SiO2 and Si are selected as the mediums according to the barrel radiation characteristic wavelength of 812 m. With the consideration of the dispersion relation, an insulating coating with photonic crystal structure is designed. Mathematical computation indicates that when the two mediums each have 4 layers and their geometric thicknesses are 1330 nm and 825 nm respectively, there will be a strict band gap of 812 m. When the geometric thicknesses of the two mediums increase, the band gap will have red shifts and the width will increase, and vice versa. As long as the geometry thickness variations of the two mediums are less than 10%, the original band gap will always exists. When the mediums are of 78 layers, the coating form a strict band gap in the above mentioned wavelength range. With the medium layer number increasing, there will be no substantial change with the band gap. The band gap structure is not sensitive to the change of incidence angle.
Investigations of space charge limited effects in diode with Coulomb's law
Authors: Zuo Ying-Hong  , Wang Jian-Guo  , Zhu Jin-Hui  , Fan Ru-Yu  ,   Department of Engineering Physics, Tsinghua University, Beijing 100084, China;,   Northwest Institute of Nuclear Technology, Xi'an 710024, China
Published: December 2020

Vacuum diode is a critical component of the apparatus which is the source of electron beams, the emitted electrons from the cathode of the diode have strong space charge limited effects. Based on Coulomb's law, the distributions of electric field in cathode-anode gap for different values of the ratio of radius to gap distance, R/D, are calculated numerically with the model of space charge limited effects in a planar vacuum diode. This method can avoid solving a non-linear differential equation which is used to yield the Child-Langmuir law from Poisson's equation. The results demonstrate that the only difference between the results from Coulomb's law and Child-Langmuir law is a modification factor, which is shown to be related to the potential difference across the gap. The results also show that one-dimensional space charge limited law will be a good approximation for the practical planar diode if the parameter R/D is beyond 10, but it can present a large error if the parameter R/D is small. Therefore it should be cautiously used.
Threshold-voltage and hole-sheet-density model of quantum well Si/SiGe/Si p field effect transistor
Authors: Li Li  , Liu Hong-Xia  , Yang Zhao-Nian  ,   Key Laboratory for Wide Band Gap Semiconductor Materials and Devices of Education, School of Microelectronics, Xidian University, Xi'an 710071, China
Published: December 2020

The low hole mobility restricts the application of Si complementary metal-oxide-semiconductor in high frequency fields. In this paper, the SiGe p-metal-oxide-semiconductor field-effect-transistor (PMOSFET) is studied. By numeric modeling and analysis, the vertical potential distribution of the device is obtained through solving one-dimensional Poisson equations, and the threshold-voltage model is established. The effects of Ge-profile, thickness of Si buffer layer, thickness of Si cap layer and substrate doping on the threshold-voltage are discussed. In SiGe layer, the quantization effect of the potential well in valence band is taken into account. When the gate voltage is large enough, the holes in SiGe channel layer will transit to the Si/SiO2 interface due to band bending and energy level splitting, causing the degradation of device performance. Thus, the hole-sheet-density model in quantum channel of SiGe PMOSFET is established, and the concept of the maximum operating gate voltage is proposed, moreover the channel saturation induced by gate voltage is calculated and analyzed. The results show that the threshold voltage and the maximal operating gate voltage are related to Ge-profile, and a proper increase of Ge-profile can extend the range of the operating gate voltage effectively.