bluuebunny/crossref_metadata_2025 huggingface dataset:
Coherence parameters of partially chaotic sources in relativistic heavy-ion collisions
Authors: Chen Xiao-Fan  ,   Department of Physics, Harbin Institute of Technology, Harbin 150001, China
Published: December 2020

The coherence parameters of partially chaotic pion sources in relativistic heavy-ion collisions for two statistical ensembles are given.
Study on the physical properties of molecule LiF in external electric field
Authors: Xu Mei  , Linghu Rong-Feng  , Li Ying-Fa  , Yang Xiang-Dong  , Wang Xiao-Lu  ,   School of Physics and Electronic Science, Guizhou Normal University, Guiyang 550001, China;,   School of Physics and Electronic Science, Guizhou Normal College, Guiyang 550018, China;,   Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, China
Published: December 2020

In this paper,the ab initio method of quantum mechanics is used to optimize the geometric structure of the ground state of LiF molecule with the DFT B3LYP method and 6-311basis in electric fields ranging from -0.015 to 0.015 a.u. The effects of external electric fields on the system energy, bond distance, dipole moment,energy levels, HOMO-LUMO gaps, charge distribution and the infrared spectrum are studied. The results show that the molecular bond distance, dipole moment, HOMO-LUMO gaps and the total atomic charges gradually increase with the increase of the external electric field along the molecular axis Z. At the same time, the total energy of the molecule, frequency and IR intensity decrease and the energy of dissociation becomes smaller with the increase of the external electric field.
Triply differential cross-sections for single ionization of sodium by electron impact in doubly symmetric geometry
Authors: Sun Shi-Yan  , Jia Xiang-Fu  , Miao Xiang-Yang  , Li Xia  , Ma Xiao-Yan  ,   Centure for research of Molecule Science, School of Physics and Information Engineering, Shanxi Normal University, Linfen 041004, China
Published: December 2020

Dynamically screened three-Coulomb-wave model (DS3C) is used to study the single ionization of the 3S orbital of sodium by electron impact. Triply differential cross-sections (TDCSs) are calculated in doubly symmetric geometry at excess energies of 6, 10, 15, 20, 30, 40, 50 and 60 eV using a parameterized optimized effective potential. Comparisons are made between recently experimental data and theoretical predictions of the three-Coulomb wave function (3C) approach and distorted-wave Born approximation (DWBA). The angular distribution of the present TDCS is found to qualitatively reproduce the reported experimental data. It is shown that dynamically screened effects are important in this geometry.
Influence of doped rare earth elements on the dehydrogenation properties of VH2
Authors: Li Rong  , Luo Xiao-Ling  , Liang Guo-Ming  , Fu Wen-Sheng  ,   Laboratory of Functional Materials, Chongqing Normal University, Chongqing 400047, China
Published: December 2020

In this paper, using the plane waves ultrasoft pseudopotential method which is base on the first principles of DFT, we study the effects of C, Si, Ge, Sn and Pb alloying on the electronic structure and dehydrogenation properties of VH2. The calculated results show that the electron density of Ef fermi level is higher than that of pure VH2 alloy, exhibiting that the structural stability becomes weakened thus the hydrogen desorption property of VH2 can be improved. Moreover, the computed results of electron density of V-H bond also demonstrate that the interaction between V and H atoms decreases, also showing that the hydrogen desorption property of VH2 is improved. At the same time, it is found from the calculated results that the Mulliken population of V-s orbital increases whereas that of V-d orbital decreases, which is related to the enhanced dehydrogenation property alloyed by La, Ce and Pr.
Investigation of L-band higher order depressed magnetically insulated transmission line oscillator
Authors: Qin Fen  , Wang Dong  , Chen Dai-Bing  , Wen Jie  ,   Key Laboratory of High Power Microwave Technology, Institute of Applied Electronics, China Academy of Engineering Physics, Mianyang 621900, China
Published: December 2020

A novel higher order mode depressed L-band magnetically insulated transmission line oscillator (MILO) device is put forward by destroying the-mode oscillating condition of HEM11 mode. High frequency analysis and PIC simulation are carried out. The simulation results reveal that the novel MILO device oscillates in TM00 mode and successfully suppresses the higher order HEM11 mode generation. Contrastive experiments are carried out. Purified 1.3 GHz microwave obtains a corresponding fundamental mode oscillation in higher order depressed MILO in contrast with original MILO which obtains a 1.42 GHz microwave output.
New method of generating self-imaged optical bottle beams and particles captured
Authors: Cheng Zhi-Ming  , Wu Feng-Tie  , Zhang Qian-An  , Zheng Wei-Tao  ,   College of Information Science & Engineering, Huaqiao University, Quanzhou 362021, China
Published: December 2020

We propose an novel optical element-liquid axicon-to generate self-imaged bottle beams in this paper. From the diffraction theory combined with geometrical optics the light field behind the liquid axicon is analyzed, and the result shows that when the refractive index of infused liquid is smaller than that of the axicon material, it can produce self-imaged optical bottle beams. Through simulation with software MathCAD, we obtain the conversion process of a complete self-imaged optical bottle beam cycle and the evolution process of the bottle beam. We find that the coherent length of self-imaged bottle beams generated by liquid axicon is adjustable. In this paper, we analyze how to use self-imaged bottle beams to capture the particles, and the advantages of capturing multilayer particles using self-imaged bottle beams are also discussed.
Study on anisotropic diffraction properties of holographic dispersed liquid crystal transmission grating
Authors: Huang Wen-Bin  , Deng Shu-Peng  , Liu Yong-Gang  , Peng Zeng-Hui  , Yao Li-Shuang  , Xuan Li  ,   State Key Laboratory of Applied Optics, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, China;,   Graduate School of Chinese Academy of Sciences, Beijing 100049, China
Published: December 2020

In this paper, we study the anisotropic diffraction properties of transmission grating based on scaffolding morphology holographic dispersed liquid crystal. Due to the absence of liquid crystal droplet formation within the grating, a simple model is proposed and combined with the anisotropic coupled-wave theory to investigate the diffractive properties. The detailed comparison between experiment and theory indicates that the alignment of liquid crystal molecules in the LC-rich region is along the grating vector.
Fabrication of nanoporous metal by selective electrochemical dealloying from laser cladding Cu-Mn alloys
Authors: Dong Chang-Sheng  , Gu Yu  , Zhong Min-Lin  , Ma Ming-Xing  , Huang Ting  , Liu Wen-Jin  ,   Department of Mechanical Engineering, Key Laboratory for Advanced Materials Processing Technology, Ministry of Education, Tsinghua University, Beijing 100084, China
Published: December 2020

The nanoporous metal is fabricated by means of hybrid laser processing in combination with electrochemical dealloying. Cu-Mn alloy coatings with fine shape, low dilute ratio and refined microstructure are fabricated on medium carbon steel by means of laser processing. Polarization curve indicates that the Cu-Mn alloy shows selective dissolution characteristics for different electrolytes. Nanoporous Cu and nanoporous Mn are fabricated with optimal electrochemically dealloying parameters. Nanoporous Cu has pore sizes rangeing from 30 to 50 nm, while the surface morphology of the porous Mn shows a ribbon-like structure with ultrahigh roughness factor up to 900. Finally, the potential-pH diagram is used to explain the mechanism of the dealloying.
Theoretical research on the generation of coherent supercontinuum
Authors: Li Ying  , Hou Jing  , Wang Yan-Bin  , Jin Ai-Jun  , Jiang Zong-Fu  ,   College of Optoelectric Science and Engineering, National University of Defense and Technology, Changsha 410073, China
Published: December 2020

The degree of coherence of the supercontinuum(SC) directly determine the resolution and the precision in many optical apparatus, so how to achieve highly coherent SC is one of the focuses in nonlinear optics. It is shown that modulation instability (MI) is the key element that influences the coherence of SC. Therefore an effective way of achieving coherent SC is to avoid MI and to use other nonlinear effects such as self-phase modulation (SPM). We design a kind of photonic crystal fiber (PCF) which has an all-normal group velocity dispersion (GVD) profile. After numerical investigation on the generation of SC in the PCF we obtain the degrees of the SC in different lengths. Results indicate that for the generated SC by pumping 50 cm of this PCF with TFWHM=400 fs unchirped pulse Gaussian pulse can realize high coherence in the entire broadening area on condition that relative power is larger than -80 dB.
Raman effect on parametric amplification gain spectrum in birefringence fiber
Authors: Jia Wei-Guo  , Qiao Li-Rong  , Wang Xu-Ying  , Yang Jun  , Zhang Jun-Ping  , Ke Neimule  ,   School of Physical Science and Technology, Inner Mongolia University, Hohhot 010021, China;,   Inner Mongolia Radio & TV University, Hohhot 010010, China
Published: December 2020

According to the wave equation used when the optical pulse propagation in the fiber, the nonlinear coupled equation is a deduced under the joint actions of Raman effect and parametric amplification in the birefringent. with Lorentzian model of parallel Raman gain spectrum, the gain is obtained by combining the Raman effect and the parametric amplification when the pump wave polarization is oriented at 45 between the birefringent fiber axes. The gain spectrum is discussed as a function of the input parameters (input power, the group velocity mismatch) in different dispersion regimes. The result shows that Stokes and anti-Stokes gain spectra are asymmetric because of Raman effect. The gain appears as primarily anti-Stokes wave in anomalous dispersion regime, and Stokes wave in normal dispersion regime.
Combination resonance bifurcations and chaos of some nonlinear relative rotation system
Authors: Li Hai-Bin  , Wang Bo-Hua  , Zhang Zhi-Qiang  , Liu Shuang  , Li Yan-Shu  ,   Key Lab of Industrial Computer Control Engineering of Hebei Province, Yanshan University, Qinhuangdao 066004, China;,   M.D. Department of Diagnostic Radiology, The Military General Hospital of Beijing PLA, Beijing 100700, China
Published: December 2020

The bifurcation and chaotic motion of some nonlinear relative rotation system with heteroclinic orbit is studied. By using dissipative system Lagrange equation, the dynamics equation of nonlinear relative rotation system under combination harmonic excitations is established. Firstly, the bifurcation response equation of relative rotation system under combination resonance is deduced with the method of multiple scales. Singularity analysis is employed to obtain the transition set of steady motion. Secondly, the Melnikov function of heteroclinic orbit is solved according to heteroclinic orbit parameter equation of relative rotation system. The critical condition of chaos about Smale commutation is given. Finally, numerical method is employed to analyze the influences of different system parameters on chaotic motion by bifurcation diagram, the maximum Lyapunov, phase trajectory and Poincare map.
Atomistic study of deposition process of Be thin film on Be substrate
Authors: Huang Xiao-Yu  , Cheng Xin-Lu  , Xu Jia-Jing  , Wu Wei-Dong  ,   The Centre of Laser Fusion Research; China Academy of Engineering Physics, Mianyang 621900, China;,   Hubei University of Education, Department of Physics and Electronics, Wuhan 430205, China;,   Institute of Atomic and Molecular Physics; Sichuan University, Chengdu 610065, China
Published: December 2020

The deposition process for Be atoms on Be substrate is studied using molecular dynamic simulations. The morphologies of the deposited films are distinctly different under different incident energies. In a specified range, the surface roughness of the film decreases with the increase of the incident energy. However, the over-high incident energy is unfavourable for reducing the surface roughness of the film. The distributions of the coordination numbers and potential energy of the single atom are used to analyze the film structure under different incident energies. With the bigger incident energy the density of the film is bigger and the distribution of the potential energy of the single atom is more continuous. At the same time, the distribution of the atomic stress is more continuous. Finally, the energy conversion process of the single atom is given, and the influence of the initial incident energy on the locally accelerated energy near the substrate is analyzed.
Magnetoelectric properties of quantum paraelectric EuTiO3 materials on the strain effect
Authors: Zhou Wen-Liang  , Xia Kun  , Xu Da  , Zhong Chong-Gui  , Dong Zheng-Chao  , Fang Jing-Huai  ,   School of Sciences, Nantong University, Nantong, 226007, China;,   School of Physical Sciences and Technology, Suzhou University, Suzhou 215006, China
Published: December 2020

Because of the strong coupling between the magnetic and dielectric properties, the study of quantum paraelectric EuTiO3 has attracted more and more attention in both theoretical and experimental research recently. In this paper, the first principles based on the density functional theory within the generalized gradient approxiamtion is used to investigate the magnetic and electronic structure of quantum paraelectric EuTiO3, and to analyze the effects of the strain on the magnetic and strutural phase transition, in turn to discuss the possible magnetoelectric coupling mechanism of this material. The calculations show that EuTiO3 with the strain-free is in a paraelectric cubic and G-type antiferromagnetic state at low temperature, while appling either compressive or tensile strain along the c-axis to it, the balance of hybridization between Ti 3d and O 2p orbit will be breaken and EuTiO3 will transite from paraelectric and G-antiferromagnetic to ferroelectric-ferromagnetic structure as the strain is increased to a certain value. All those indicate the strong spin-lattice coupling effect in EuTiO3.
Photoluminescence studies of electron irradiated diamond
Authors: Wang Kai-Yue  , Li Zhi-Hong  , Gao Kai  , 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

After electron irradiation, a large number of interstitial and vacancy-related centres are created in diamond. In this paper, We compare these irradiation-induced centres among ultra pure, nitrogen doped and boron doped crystals by using 488 nm and 325 nm lasers. Results show that some new interesting emissions are observed after the donor or acceptor atoms have been implanted into diamond, such as nitrogen-vacancy complex, DB1 centre.
Microstructure evolution model of zirconia solid electrolyte based on AC impedance model analysis
Authors: Hu Yong-Gang  , Xia Feng  , Xiao Jian-Zhong  , Lei Chao  , Li Xiang-Dong  ,   Department of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
Published: December 2020

The effect of grain boundary on conductivity in multicomponent polycrystalline solid electrolyte has become a bottleneck for the development of high temperature solid electrolyte materials. The corresponding relationship between the microstructure and conductivity at high temperature is difficult to obtain based on the traditional methods of grain boundaries observation. In view of this, the variable temperature AC impedance characteristics of partially stabilized zirconia (PSZ) solid electrolyte material are investigated, and their fitting to AC impedance spectrum is analyzed. It is found that the fitting equivalent circuits varies with temperature increasing. By analyzing the physical meanings of different equivalent circuits, the microstructure evolution model of PSZ electrolyte material at elevated temperature is obtained. A microstructure model of 'short-range ordered ' with the structure of 'boundary bridge' is deduced after further analysis, which could provide the reference for improving the grain boundary conductivity in PSZ electrolyte materials.
Progress of coupled superconducting qubits
Authors: Zhao Na  , Liu Jian-She  , Li Tie-Fu  , Chen Wei  ,   Institute of Microelectronics, Tsinghua University, Beijing 100084, China;,   Tsinghua National Laboratory for Information Science and Technology (TNList), Tsinghua University, Beijing 100084, China
Published: December 2020

Quantum system based on superconducting circuit is considered as one of the most promising schemes to realize quantum computers due to its controllability, low dissipation and scalability. To implement large scale quantum computation, coherent coupling between qubits is crucial for controlling and transferring quantum states. In this review paper, we summarize the progress of coupled superconducting qubits, including local coupling via capacitance or inductance, multiple qubits coherent interaction through one-dimensional resonator as circuit quantum electrodynamics, and superconducting qubits in a three-dimensional waveguide cavity. Hamiltonians of various coupling schemes are analyzed and classification of these coupling structures is summarized based on the coupling range and tunability.
Implementation of the scheme of a quantum information signature based on weak nonlinearity
Authors: Ding Dong  , Yan Feng-Li  ,   Department of Basic Curriculum, North China Institute of Science and Technology, Beijing 101601, China;,   College of Physics Science and Information Engineering, Hebei Normal University, Shijiazhuang 050024, China
Published: December 2020

A quantum information signature protocol based on weak nonlinearity and the symmetrical quantum cryptography is proposed. A sender can send classical messages and can judge whether the messages have been modified or replaced by an adversary. When the authentication of messages is completed, the fact of the communication can neither be disavowed by the sender nor be denied by the receiver because of the existence of an honest arbitrator.
Experimental study on frequency stabilization method of internal-mirror He-Ne laser
Authors: Qian Jin  , Liu Zhong-You  , Shi Chun-Ying  , Liu Xiu-Ying  , Wang Jian-Bo  , Yin Cong  , Cai Shan  ,   Division of Metrology in Length and Precision Engineering, National Institute of Metrology, Beijing 100013, China
Published: December 2020

Frequency of an internal-mirror He-Ne laser is stabilized by using a micro cooling fan, instead of traditional heating method. Both the relationship between driving voltage and rotating speed and the thermal expansion of the intermal-mirror laser are discussed. The cavity length of the laser is controlled and adjusted by air cooling. The frequency stabilization is based on a theory of power balance between two longitudinal modes. The average temperature of the laser tube is less than 50 ℃ when the frequency is stabilized. A frequency fluctuation of less than 1.4 MHz in 20 h and a frequency relative standard uncertainty of U=4.710-9 in 4 months are evaluated by measuring the beat signal with a high-precision laser stabilized by iodine.
Relation analysis between cathode ablation and voltage for a magnetically insulated transmission line oscillator
Authors: Chen Dai-Bing  , Zhang Yun-Jian  , Zhang Bei-Zheng  , Wang Dong  , Qin Fen  , Wen Jie  , Jin Xiao  , Wu Yong  , Yu Ai-Ming  ,   Science and Technology on High Power Microwave Laboratory, Institute of Applied Electronics, China Academy of Engineering Physics, Mianyang 621900, China
Published: December 2020

Through the particle-in-cell simulation and experimental investigation, the relation between the cathode ablation and the input voltage waveform of a magnetically insulated transmission line oscillator (MILO) is analyzed. And the key factor that results in the cathode ablation is found. The figures and process that the electron beam bombards back the cathode are obviously presented. By waveform adjustment of the low impedance accelerator, the reverse voltage of the input voltage to MILO is restrained, and the cathode ablation problem of the MILO driven by the low impedance accelerator is solved. Analysis results show that the electron beam which has been hauled from the cathode by the right direction voltage moves back, which the reverse voltage with adequate amplitude driven, and the beam bombards back the the cathode. The reverse current is formed and the cathode of the MILO device is ablated. Therefore, the reverse voltage immediately following the down slope of the input voltage is a key factor.
Dispersion analysis of reflection grism-pair applied to dispersion compensation
Authors: Su Juan  , Feng Guo-Ying  , Zou Qi-Hui  , Liu Zhong-Hua  , Qiu Yi  ,   School of Science, Southwest Petroleum University, Chengdu 610500, China;,   College of Electronics and Information Engineering, Sichuan University, Chengdu 610064, China
Published: December 2020

We provide detailed analytical expressions of group-delay dispersion and three-order dispersion for reflection grism-pair using angle dispersion and material dispersion. The dispersion formulas obtained in this study are consistent with the results of the ray-tracing method. The analytical expressions can be used to design a grism-pair for compensating for the dispersive material. Furthermore, the dispersion performances of the grism pair depending on structural parameters and temperature are comprehensively analyzed. The results show that the parameters have a large influence on the dispersion of grism, such as incidence angle, grating constant, and apex angle of the prism. To compensate for material dispersion of amplifying medium, we can adjust the above parameters to obtain group delay dispersion and third order dispersion.
Image reconstruction algorithm for steady-state diffuse optical tomography with structural priori information
Authors: Deng Yong  , Zhang Xuan-Xuan  , Luo Zhao-Yang  , Xu Jun  , Yang Xiao-Quan  , Meng Yuan-Zheng  , Gong Hui  , Luo Qing-Ming  ,   Wuhan National Laboratory for Optoelectronic, Key Laboratory of Biomedical Photonics of Ministry of Education, Huazhong University of Science and Technology, Wuhan 430074, China
Published: December 2020

Diffuse optical tomography is a non-invasive and non-ionizing optical imaging technique with low cost, while it suffers from low spatial resolution and is very difficult to achieve quantitative measurement. In order to improve the resolution and reconstruct the optical coefficients accurately, in this paper, we present an image reconstruction algorithm based on finite element method for steady-state diffuse tomography with structural priori information. Imaging model is characterized by the steady-state diffuse equation. The spatial structural information from micro-CT is introduced into the inverse problem by the Laplace regularization and Levenberg-Marquardt method to solve the inverse problem where the Jacobian matrix is obtained by adjoint method. The simulation results show that the algorithm presented is able to obtain the accurate distribution of optical coefficients and increase the convergence speed of iteration evidently.
Influence of digital averaging on the signal-to-noise improvement ratio of temperature control system used in single-photon detector at infrared wavelength
Authors: Wang Jin  , Wei Zheng-Jun  , Wang Geng  , Guo Li  , Wang Jin-Dong  , Zhang Zhi-Ming  , Guo Jian-Ping  , Guo Bang-Hong  , Liu Song-Hao  ,   Laboratory of Nanophotonic Functional Materials and Devices, Laboratory of Quantum Information Technology, South China Normal University, Guangzhou 510006, China
Published: December 2020

According to performance requirement of high precision temperature control system used in single-photon detector, the signal-to-noise improvement ratio (SNIR) achieved by digital averaging used in it is analyzed, and the functional relation between SNIR and average times, sampling period, length of sampling time and bandwidth of band limited white noise is given. Aiming at practical application, on condition that the total sampling time is limited, the influences of average time and sampling period on the SNIR of the system are calculated respectively, the expression of SNIR is given and the optimal sampling time is defined.
Decoherence of a photon-subtraction-addition coherent state in a thermal environment
Authors: Zhang Hao-Liang  , Jia Fang  , Xu Xue-Xiang  , Guo Qin  , Tao Xiang-Yang  , Hu Li-Yun  ,   College of Physics and Communication Electronics, Jiangxi Normal University, Nanchang 330022, China
Published: December 2020

We investigate the nonclassicality and decoherence of a photon-subtraction-addition coherent state (a++a)m|a in a thermal environment. Its nonclassicality is discussed by deriving analytically Mandel's Q parameter, photon number distribution, and Wigner function. It is shown that if the condition |2z*+ -*|2 1 is satisfied, the Wigner function always presents the negativity for the one-order photon-subtraction-addition coherent state (m=1). Based on the evolution formula of Wigner function, we derive a compact expression for Wigner function in the thermal environment. It is found that when t(1/2)ln[(2N+2)/(2N+1)] there is no negativity for the case of m=1. In addition, the evolution of nonclassicality is discussed in terms of the negative volume of Wigner function.
Experimental study of L-H transition triggered by supersonic molecular beam injection in the HL-2A tokamak
Authors: Feng Bei-Bin  , Yao Liang-Hua  , Chen Cheng-Yuan  , Ji Xiao-Quan  , Zhong Wu-Lü  , Shi Zhong-Bing  , Yu De-Liang  , Cui Zheng-Ying  , Song Xian-Ming  , Duan Xu-Ru  ,   Southwestern Institute of Physics, Chengdu 610041, China
Published: December 2020

Features of L-H transition are investigated using the supersonic molecular beam injection (SMBI) with directional velocity under low heating powers in the present paper. Comparing the edge density profiles, it is analyzed that the conventional gas puffing (GP) and SMBI have effects on L-H transition. Experimental results suggest that the SMBI does directly trigger L-H transition on HL-2A, and it considerably reduces the power threshold of L-H transition. After abundant experimental data are analyzed and processed, it is found that the minimum L-H transition power with SMBI decreases by 10% when it is compared with GP trigged H-mode under same conditions.
Monte Carlo model and variance reduction method based on lidar of ship wake
Authors: Liang Shan-Yong  , Wang Jiang-An  , Zhang Feng  , Wu Rong-Hua  , Zong Si-Guang  , Wang Yu-Hong  , Wang Le-Dong  ,   Electronic Engineering College, Naval University of Engineering, Wuhan 430033, China;,   China Shipbuilding Industry Group No. 717 Research Institute, Wuhan 430033, China
Published: December 2020

The numerical simulation of ship wake laser scattering mechanism and the detection process are important foundations for the laser detection and guidance of the ship wake. The feasibility that Monte Carlo method is introduced into the numerical simulation of lidar of ship wake is analyzed firstly. The Monte Carlo simulation model of laser detection of ship wake is developed with the actual parameters of self-developed lidar of ship wake. The causes of the large variance and low photon utilization of simulation results are in-depth analyzed by statistics on the simulation results. To resolve this problem, the method of photon collision forced in the receive optical fields, the photon splitting method with the total free pach of photon serving as a criterion, and the conbination of the two methods are put forward based on partial sampling theory and the basic principle of division-roulette bet. The comparative analyses of the simulation and the experimental results show that the proposed model simulation results fit to experimental data better, thus the correctness of the model is verified. The photon collision forced in the receive optical field and division-the roulette method can effectively reduce the variance and increase the photon utilization. In this paper, the Monte Carlo method is introduced into the simulation process of lidar of ship wake.
One-dimensional simulation of radiation transport in three-dimensional cylinder
Authors: Song Tian-Ming  , Yang Jia-Min  ,   Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900, China
Published: December 2020

In indirect driven inertial confinement fusion experiments, one-dimensional radiation hydrodynamics code is used to simulate radiation transport in material confined in a cylinder and large bias is generated due to two- or three-dimensional lateral effects like energy losses into the cylinder wall. Lateral X-ray radiation losses such as cylinder wall loss and direct leak from the detection holes are simulated through analytical view factor equations and albedo power laws. Modifications are made for a one-dimensional radiation hydrodynamics code MULTI which is successfully used in the simulation of measured hydrodynamic trajectory of X-ray-heated gold plasma and better result is obtained than without taking lateral effect into account, which proves that this modification is practical.
Interactions between ions with different values of Ep/q and alumina capillaries
Authors: Xi Fa-Yuan  , Lü Hui-Yi  ,   Key Subject Laboratory of National Defence on Nuclear Waste and Environment Safety, Southwest University of Science and Technology, Mianyang 621010, China
Published: December 2020

Study of ion guiding effect of capillaries in insulator is of significance for developing passive-type ionic optics. Interactions between ions with different values of Ep/q, such as 150 keV O3+, 0.32 MeV O+ and 2 MeV O2+, and alumina capillaries are investigated. For projectile ions of 150 keV O3+, a guiding effect exists during the passage of the projectile ions through the capillaries. As the capillaries are tilted with respect to the projectile ion beam, the projectile ions can still pass through the capillaries considerably and the charge state remains unchanged; the spectrum of angular distribution of the ions out of the capillaries shifts by an angle the same as the tilt angle of the capillaries; the penetrating rates of the projectile ions for different tilt angles of the capillaries can be fitted to Gaussion function. For 0.32 MeV O+ and 2 MeV O2+ ions impinging on alumina capillaries, no guiding effect occurs in the interaction process. The maximum value of Ep/q of the projectile ions for guiding effect to occur is less than 320 kV.
A novel interconnect-optimal power model considering self-heating effect
Authors: Zhang Yan  , Dong Gang  , Yang Yin-Tang  , Wang Ning  , Wang Feng-Juan  , Liu Xiao-Xian  ,   Key Laboratory of Ministry of Education for Wide Band-Gap Semiconductor Materials Devices, Microelectronics Institute, Xidian University, Xi’an 710071, China
Published: December 2020

Based on the distributed interconnect power model, a novel dynamic power model is presented in this paper, in which a non-uniform interconnection structure is adopted. This model takes into account the self-heating effect and is constrained by delay, bandwidth, area, minimum interconnect width and minimum interconnect space. The validity of the proposed model is verified by 90 nm and 65 nm complementary metal-oxide semiconductor technology. The results indicate that the proposed model can cause a power consumption reduction as high as 35%, and yet the delay, area, and bandwidth are not deteriorated, when compared with the conventional power model. The proposed optimal model can be used for designing large scale interconnect router and clock network in network-on-chip structure.
First-principles study on anatase TiO2 photocatalyst codoped with nitrogen and cobalt
Authors: Zhang Xue-Jun  , Zhang Guang-Fu  , Jin Hui-Xia  , Zhu Liang-Di  , Liu Qing-Ju  ,   School of Communication and Electronic Engineering, Hunan City University, Yiyang 413000, China;,   Key Laboratory of Nanomaterials and Nanotechnology of Yunnan Province, Yunnan University, Kunming 650091, China
Published: December 2020

The microstructures and optical properties of N and Co-codoped anatase TiO2 are investigated by using the plane-wave ultrasoft pesudopotential method of first-principles. The calculated results show that the octahedral dipole moment of anatase TiO2 increases after N and Co codoping, which is favorable for effective separation of photogenerated electron-hole pairs. Some new impurity energy levels of codoped TiO2 appear between the conduction band and the valence band, which results in the red shift of the absorption wavelength toward visible-light region and an apparent increase in performance of light absorption. These impurity energy levels can promote the effective separation of photogenerated electron-hole pairs, which facilitates the improvement of the photocatalytic efficiency of codoped TiO2. The band edge redox potential of codoped TiO2 is only slightly changed compared with that of pure TiO2, which means that the strong redox capacity of codoping photocatalyst is still excellent.
Mageto-transport properties of serial double quantum dots in the spin blockade regime
Authors: Zou Cheng-Yi  , Wu Shao-Quan  , Zhao Guo-Ping  ,   School of Physics and Electronic Engineering, Sichuan Normal University, Chengdu 610068, China
Published: December 2020

With the two-impurity Anderson model Hamiltonian, we theoretically study the magneto-transport properties of the serially coupled double quantum dot system in a spin blockade regime, and solve Hamiltonian by the master equation approach. We find that the spin flip tunneling between dots due to the spin-orbit coupling can lift the quantum dot spin blocking. We also study the effects of the spin flip of quantum dots due to the hyperfine interactions and the spin exchange interaction on magnetic transport properties of the system. Some valuable results are obtained and the relevant problems are discussed.
VO2 low temperature deposition and terahertz transmission modulation
Authors: Sun Dan-Dan  , Chen Zhi  , Wen Qi-Ye  , Qiu Dong-Hong  , Lai Wei-En  , Dong Kai  , Zhao Bi-Hui  , Zhang Huai-Wu  ,   State Key Laboratory of Electronic Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054, China;,   National Key Laboratory of Science and Technology on Communication, University of Electronic Science and Technology of China,Chengdu 610054, China
Published: December 2020

Recently, the applications of vanadium dioxide film (VO2) in terahertz functional devices have attracted much attention because VO2 has a remarkable response to THz wave, In this work BK7 glass a material highly transparent to both THz and optical band is adopted as a substrate. High-quality VO2 film is deposited on a BK7 substrate using low temperature magnetron sputtering technology. The crystallinity and microstructure of the thin film are investigated by X-ray diffraction and atomic force microscopy. The results indicate that the as-deposited film crystallizes directly into single-phase VO2 with (011) preferred orientation and compact nanostructure. Under a heating-cooling cycle, the film undergos a metal-insulator transition with an abrupt resistivity change reaching more than 4 orders of magnitude. Terahertz transmission modulation is characterized by terahertz time domain spectrum, and a giant modulation depth of 89% is obtained. Due to the high transparence and the huge modulation effect, the VO2/BK7 can be widely used for THz devices such as modulators and switches.
Modulation of the band structure of layered BN film with stain
Authors: Xie Jian-Feng  , Cao Jue-Xian  ,   Department of Physics, Xiangtan University, Xiangtan 411105, China
Published: December 2020

With the density of function with pesudopotentional and plane-wave method, we study the strain effect on band structure of multi-layered BN film. It is found that the band gap of BN film decreases linearly with the increase of tensile strain, and the slope of the band gap-strain curve is independent of the BN stacking and the number of the BN layers, indicating that the band structure of BN film is determined by the interlayer interaction rather than the intralayer interaction.
Phase drift of magnetoelectric effect in Terfenol-D/PZT composite materials
Authors: Shi Zhan  , Chen Lai-Zhu  , Tong Yong-Shuai  , Zheng Zhi-Bin  , Yang Shui-Yuan  , Wang Cui-Ping  , Liu Xing-Jun  ,   Deparment of Materials Science and Engineering, College of Materials, Xiamen University, Xiamen 361005, China
Published: December 2020

Bulk Terfenol-D/PZT composite material with laminated structure is prepared by sticky combination method. The magnetoelectric hysteresis loops under different frequencies are measured and analyzed by new plotting method in the polar coordinates. The results show that tiny phase drift occur in a non-resonant-frequency magnetoelectric hysteresis loop and significant phase drift as large as 90 degrees accompanied with a giant magnetoelectric effect occurs in a resonant-frequency magnetoelectric hysteresis loop. Terfenol-D powder/Epoxy/PZT composite material is prepared by fill method and used as contrast material. Comparison reveals that the phase drift in the non-resonant frequency magnetoelectric hysteresis loop is induced by eddy current in the bulk ferromagnetic constituent, while around the resonant frequency, the significant phase drift is derived from the variation of the elastic property induced by the applying magnetic field.
Bond energy and coordination number model for relaxor ferroelectrics
Authors: Cao Wan-Qiang  , Shu Ming-Fei  ,   School of Materials Science and Engineering, Hubei University, Wuhan 430062, China
Published: December 2020

Based on the gaussian-type distributions of bond energy and coordination number for barium titanate systematic ferroelectrics doping with a certain quantity of dopants, the bond energy and coordination number fluctuation model is used to derive the relationship between peak of dielectric constant and testing frequency. The universal Vogel-Fulcher function of the relationship is demonstrated, when the fluctuations of bond energy and coordination number approach to each other. The frozen temperature of the Vogel-Fulcher function is related only to actuation energy and relative fluctuation of bond energy. The mechanisms of dispersion due to homogenous distribution of dopants in low doping concentration and relaxor due to gaussian-type distribution of dopants over a critical concentration are investigated. It is suggested that strong inhibitory effect of substituted ions on formation and growth of ferroelectric domain is the main source of bond energy fluctuation and coordination number fluctuation.
Field emission properties of silicon doped AlGaN thin film
Authors: Wang Jing  , Wang Ru-Zhi  , Zhao Wei  , Chen Jian  , Wang Bo  , Yan Hui  ,   Laboratory of Thin Film Materials, College of Materials Science and Engineering, Beijing University of Technology, Beijing 100124, China;,   Instrumental Analysis of Research Center, Sun Yat-sen University, Guangzhou 510275, China
Published: December 2020

Aluminum gallium nitride (AlGaN) thin films are prepared by pulsed laser deposition with different silicon doping concentrations from 0.5% to 2%. The field emission measurement shows that the 1% Si-doped AlGaN film has the best field emission property. Compared with undoped film, the Si-doped film has a large emission current density and a low threshold field. The increase of doping concentration can increase the carrier concentration, which will add a number of supply electrons, thereby improving greatly the FE property of AlGaN film. With the doping concentration further increasing, the defect of film increases and the electron mobility reduces. The reduction of the internal supply electron is greater than the contribution of the increase of electrons concentration, which induces the field emission performance to deteriorate. This study will provide a reliable basis for designing high-performance field emission devices.
UV Raman and XPS studies of hydrogenous diamond-like carbon films prepared by PECVD
Authors: Yang Fa-Zhan  , Shen Li-Ru  , Wang Shi-Qing  , Tang De-Li  , Jin Fa-Ya  , Liu Hai-Feng  ,   Southwestern Insititute of Physics, Chengdu 610041, China;,   The Enginering and Technical College of University, Leshan 614000, China
Published: December 2020

The hydrogenous diamond-like carbon (DLC) films deposited on Si substrates using pulsed glow discharge method are investigated using Raman spectroscopy and X-ray photoelectron spectroscopy method. The UV Raman spectrum for excitation wavelength is 325 nm. UV Raman is particularly useful for hydrogenous DLC, as it gives clear measurements in the D and G peak spectral region even for highly hydrogenated samples, for which the visible Raman spectra are overshadowed by photoluminescence. The sp3 bonding of hydrogenous DLC film can be effectively studied by X-ray photoelectron spectroscopy method, and the data from the X-ray photoelectron spectroscopy method are compared with Raman results. It is found that G peak shows a shift to ward a higher wave under UV excitation. For the G peak, I(D)/I(G), G-FWHM and sp3, there exists a relationship among them.
Quick search algorithm of X-ray pulsar period based on unevenly spaced timing data
Authors: Zhou Qing-Yong  , Ji Jian-Feng  , Ren Hong-Fei  ,   State Key Laboratory of Geo-Information Engineering, Xi’an 710054, China;,   Xi’an Research Institute of Surveying and Mapping, Xi’an 710054, China
Published: December 2020

Timing information of X-ray pulsar signal is of the vital significance for realizing the autonomous navigation of spacecraft in deep space. The accurate timing model (period and period derivation) is the foundation of achieving high-precision auto-navigation solutions. Because the data that the X-ray photons arrive at the detector are unevenly spaced, both χ2 evaluation method and Lomb algorithm are analyzed. The idea is brought forward that the initial value of pulsar period is gained using the χ2 evaluation method, then the result of period is refined by Lomb algorithm. Meanwhile, the Lomb algorithm is ameliorated by the idea of fast Fourier transform algorithm, the efficiency of operation is enhanced highly. Finally the exact pulsar period is estimated, and correct pulse profile is replicated using the measured timing data from the X-ray source simulation system which used to validate the algorithm.
Cascade chaos and its dynamic characteristics
Authors: Wang Guang-Yi  , Yuan Fang  ,   School of Electronics and Information, Hangzhou Dianzi University, Hanghou 310018, China
Published: December 2020

The dependence of sensitivity on initial conditions is the essence of chaos. And the randomness of chaos originates from the high sensitivity to initial values, which is measured by the Lyapunov exponents. It is found in this paper that the cascade of chaotic systems can considerably improve the Lyapunov exponents of cascade chaos and other dynamic properties. Therefore, in this paper, we study the cascade of chaotic systems and the influence on dynamic performances of the cascade chaos, and we present the definition and conditions of chaotic system cascade. It is proved in theory that the Lyapunov exponent of cascade chaos system is a sum of Lyapunov exponents of cascade subsystems. Appropriate cascade for chaotic systems can increase system parameters and expand parameter regions of chaos mapping and full mapping, thereby enhancing initial condition sensitivity of chaotic map and security of chaotic pseudo-random sequences. For logistic map, cubic map and tent map, the dynamic characteristics of logistic-logistic, logistic-cubic and logistic-tent cascade are investigated in detail, verifying the improvements on dynamic characteristics of cascade chaos systems. The proposed chaotic cascade system can be used to generate better pseudo-random sequences for initial condition sensitivity and security.
Synchronization with different structures of uncertain chaotic system
Authors: Shao Ke-Yong  , Ma Yong-Jing  , Wang Ting-Ting  , Liu Yuan-Hong  , Yang Li  , Gao Hong-Yu  ,   College of Electrical and Information Engineering,Northeast Petroleum University, Daqing 163318, China
Published: December 2020

Based on the finite time control Lyapunov function the synchronization control between unified chaotic system and chaotic Liu system with uncertain parameters and different structures is investigated. The feedback control law does not require to know the specific value of parameter, but only depends on the variation range of the parameter. Compared with existing control method, it can effectively overcome the effect of mismatched parameters, moreover, the feedback is relatively simple and robust. Simulation results verify the effectiveness of the proposed control method.
A hybrid optimization approach to design of compact self-shielded super conducting magnetic resonance imaging magnet system
Authors: Ni Zhi-Peng  , Wang Qiu-Liang  , Yan Lu-Guang  ,   Institure of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190, China;,   Graduate University of Chinese Academy of Sciences, Beijing 100049, China
Published: December 2020

A hybrid optimization approach with a combination of linear programming and nonlinear programming algorithm for designing a compact self-shielded magnetic resonance imaging (MRI) superconducting magnet system is presented. The designed coils possess advantages of low construction costs, simple coil structure and the maximum magnetic strength within coils, current margin and electromagnetic stress easy to control. Firstly, in the stage of linear programming optimization, the feasible rectangular region can be divided into two-dimensional meshes, and a current map is calculated for meeting the magnetic field constraints over the surfaces of DSV sphere and 5 gauss stray field ellipse; Secondly, the current map has many nonzero current clusters and each cluster can be discretized into a solenoid. A nonlinear programming algorithm is employed to optimize the positions of all solenoids for minimizing the total coil volume and meeting all constraints including magnetic field which is the same as linear programming stage, and maximum magnetic strength, current margin and the gap between neighborhood inner coils. A 1.5 T compact self-shielded MRI superconducting magnet system is studied, the total coil length is only 1.32 m and the peak-peak homogeneity over 50 cm DSV is 10 ppm. The design approach is flexible and efficient for designing symmetrical and asymmetrical horizontal MRI and also open bi-planar MRI system.
Effect of rotational excitation of NO on the stereodynamics for the reaction N(4S)+NO(X2Π)→N2(X3Σg-)+O(3P)
Authors: Ma Jian-Jun  ,   Department of Applied Physics, Anhui University of Technology, Maanshan 243002, China
Published: December 2020

The stereodynamic properties of the reaction N(4S)+NO(X2Π)→N2(X3Σg-)+O(3P) in different initial reagent rotational states are studied theoretically by using the quasiclassical trajectory method on two lowest 3A" and 3A' potential energy surfaces at a collision energy of 0.6 eV. The vector properties of different rotational states on the two potential energy surfaces are discussed in detail. The results indicate that the rotational excitation of NO has a considerable influence on the stereodynamic property of reaction occurring on the 3A' potential energy surface, which can be ascribed to the early barrier on this potential energy surface.