bluuebunny/crossref_metadata_2025 huggingface dataset:
Synchronizations of chaotic neuronal networks under different couplings
Authors: Wu Wang-Sheng  , Tang Guo-Ning  ,   College of Physics and Technology, Guangxi Normal University, Guilin 541004, China
Published: December 2020

The synchronization of a two-dimensional (2D) neuronal network is investigated, based on the dynamical model of Hindmarsh-Rose neuron. In order to know the effects of different types of coupling on the synchronization of a network, we propose three coupling schemes. They are the general feedback coupling, the hierarchical feedback couplings with and without local mean field. The numerical results show that when the neighbor coupling strength is small, the hierarchical feedback couplings with and without local mean field can achieve local and global synchronizations of the network, whereas the general feedback coupling cannot achieve global synchronization. Different couplings generate different patterns in the corresponding network, so that the processes of the transition from asynchronization to synchronization in the networks are different. With the increase of coupling strength, the synchronization in the network with the general feedback or hierarchical feedback couplings is suddenly established, and the networks exhibit different coherent patterns that are aperiodic before the global synchronization occurs. However, the network with hierarchical feedback couplings and local mean field exhibits the different synchronous processes. The neurons in the same layer first achieve the transition from bursting synchronization to global synchronization, leading to the formation of target wave. Then, the synchronization region gradually expands from the center of the network. Finally, the whole networks can achieve synchronization. These results show that the lossless signal transmission can be achieved only if the appropriate coupling is applied. In addition, we find that the hierarchical feedback coupling with local mean field can facilitate synchronization.
Numerical simulation of dynamic scaling behavior of the etching model on randomly diluted lattices
Authors: Xie Yu-Ying  , Tang Gang  , Xun Zhi-Peng  , Han Kui  , Xia Hui  , Hao Da-Peng  , Zhang Yong-Wei  , Li Yan  ,   Department of Physics, China University of Mining and Technology, Xuzhou 221116, China
Published: December 2020

Surface roughening has been extensively studied in many fields of science and technology. In order to investigate the influence of imperfection of the randomly diluted lattices on dynamic scaling behavior of the surfaces, the etching model growing on diluted squares is simulated by kinetic Monte Carlo (KMC) simulation. It is found that although the scaling behavior of the etching model can be affected by imperfections of the randomly diluted lattices, the roughness and the growth exponent are larger than those of the growth on perfect squares. The scaling behavior still satisfies the Family-Vicsek dynamic scaling. In addition, the finite system size effect of the randomly diluted lattice is also calculated and analyzed.
Characterization of the p-type ZnO solid solution by doping Li under high pressure
Authors: Qin Jie-Ming  , Tian Li-Fei  , Jiang Da-Yong  , Gao Shang  , Zhao Jian-Xun  , Liang Jian-Cheng  ,   Institute of Materials Science and Engineering, Changchun University of Science and Technology, Changchun 130022, China;,   College of Physics, Inner Mongolia University of the Nationalities, Tongliao 028000, China
Published: December 2020

In this paper, stable Li-doped ZnO solid solution (ZnO: Li) is successfully prepared by sintering the mixture of ZnO and Li2O powders under a pressure of 5 GPa and at temperatures between 1200 ℃ and 1500 ℃. It is found that the high pressure and temperature conditions have significant effects on the electrical conductivity and the structure of the ZnO solid solution. The best p-type ZnO doping 4.5 at.% Li with a resistivity of 3.1 10-1cm, carrier concentration of 3.3 1019cm-3, and mobility of 27.7 cm/Vs is achieved at 1500 ℃. The p-type conduction formed in ZnO is due to acceptor formed by one substitutional Li atom at Zn site, which has an acceptor level of 110 meV. Furthermore, the effects of pressure on formation and electrical properties of the p-type ZnO are discussed.
WLW mass model in nuclear r-process calculations
Authors: Li Zhu  , Niu Zhong-Ming  , Sun Bao-Hua  , Wang Ning  , Meng Jie  ,   School of Physics Science and Nuclear Engineering, Beihang University, Beijing 100191, China;,   School of Physics, Peking University, Beijing 100871 China;,   Department of Physics, Guangxi Normal University, Gulin 541004, China
Published: December 2020

The rapid neutron-capture process (r-process), which is an interdisciplinary field of astrophysics and nuclear physics, is bound up with various characteristics of thousands of neutron-rich exotic nuclei, such as nuclear masses, and the relevant reactions. By employing the WLW microscopic-macroscopic nuclear mass model developed recently, the solar r-process abundance distribution is well reproduced in the classical r-process approach. In comparison with the well known FRDM model, the present calculation better pictures the nuclear region of A135 and A180, and especially avoids the abundance peaks at A135 often obtained in other calculations. The improvement in the r-process calculation may indicate a more suitable description of the evolution of shell structure and symmetry energy towards the drip line in the WLW model.
Study of magnetic proton recoil technology for measurement of deuterium-tritium neutron spectrum
Authors: Zhou Lin  , Jiang Shi-Lun  , Qi Jian-Min  , Wang Li-Zong  ,   Institute of Nuclear Physics and Chemistry, Mianyang 621900, China
Published: December 2020

A kind of fusion dianostics based on proton recoil method and magnetic analyzing technology is introduced. It can be used for the accurate diagnoses of plama tempreture, fuel density and neutron yield. A prototype is designed, using a high-powered Nd-Fe-B permanent dipole for magnetic analyzer, and proton position distribution in the focal plane is measured by CR-39 trajectory detector or PIN detector. The system is calibrated with a 239 Pu source, and a corresponding particle transport simulation program is worked out. The performance of the spectrometer is investigated with the Monte Carlo simulation, and neutron experiments are taken on the K-400 accelerator.
Novel CRLH TL based on fractal geometry and series power divider application
Authors: Xu He-Xiu  , Wang Guang-Ming  , Liang Jian-Gang  , Peng Qing  ,   Missile Institute, Air force Engineering University of China, Sanyuan 713800, China;,   Nanchang University, Nanchang 330031, China
Published: December 2020

A novel resonant-type composite right/left handed transmission line (CRLH TL) and its correlative lumped-element equivalent circuit model are presented based on complementary single split ring resonator pair (CSSRRP). The circuit model is investigated in depth through the Bloch theory, and the condition for balanced CRLH TL is derived. The negative refractive index and the backward wave propagation are demonstrated by the effective electromagnetic parameter retrieval. After that, a balanced electrically small CRLH TL with zero phase shift is designed at WiMAX (Worldwide Interoperability for Microwave Access) band by introducing the Koch fractal geometry into CSSRRP. For application, a series power divider is fabricated and measured. Consistent simulated and measured results confirm the design concept. The bandwidth of the proposed power divider is broadened by 56%, and the overall dimension is only 58% of its conventional counterpart based on meandered line. Thus novel CRLH TL based on fractal shape CSSRRP can be found to have an extensive application in future small-size wireless communication system.
Stochastic resonance in a gain-noise model of single-mode laser under the first-order approximation
Authors: Zhang Liang-Ying  , Jin Guo-Xiang  , Cao Li  ,   School of Physics and Electronic Engineering, Xiangfan University, Xiangfan 441053, China;,   Hubei Province Key Laboratory of Intelligent Robot, Wuhan Institute of Technology, Wuhan 430073, China;,   School of Physics, Huazhong University of Science and Technology, Wuhan 430074, China
Published: December 2020

By adding periodic signal into single-mode laser, and taking the first-order approximation to the multiplication noise of the laser gain-noise model,we find that the output signal is of the Lorentz type when we obtain power spectrum by calculating the correlated function. The signal-to-noise ratio shows the stochastic resonance occurs with the variations of intensities of the pump noise and quantum noise, and the noise intensity of resonant peak is smaller than that under the zeroth approximation.
The effect of gas puffing on plasma during slide-away discharge in the HT-7 tokamak
Authors: Lu Hong-Wei  , Zha Xue-Jun  , Hu Li-Qun  , Lin Shi-Yao  , Zhou Rui-Jie  , Luo Jia-Rong  , Zhong Fang-Chuan  ,   Department of Applied Physics, Donghua University, Magnetic Confinement Fusion Research Center (Donghua University), Ministry of Education, Shanghai 201620, China;,   Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 China
Published: December 2020

In tokamak plasma, the discharge will turn into runaway discharge from normal discharge if the plasma density becomes very low. The discharge will enter into slide-away discharge if the density decays to a critical one, in which the confinement of plasma (exactly supper thermal electrons) is better than that in normal discharge. The confinement of plasma and the anomalous Doppler instability during slide-away discharge gas puffing are investigated. The effect of gas puffing on runaway electrons during slide-away discharge is also studied in this paper. It is found that the anomalous Doppler instability can be suppressed by the gas puffing during slide-away discharge, while the confinement of plasma becomes poor, and many high energy runaway electrons occur during gas puffing.
Application of floating microwave resonator probe to the measurement of electron density in electronegative capacitively coupled plasma
Authors: Zou Shuai  , Tang Zhong-Hua  , Ji Liang-Liang  , Su Xiao-Dong  , Xin Yu  ,   Provincial Key Laboratory of Thin Films, School of Physical Science and Technology, Soochow University, Suzhou 215006, China
Published: December 2020

In electronegative or reactive plasmas, the problems such as negative ions floating near the sheath edge or deposition contamination cause more challenges for the diagnosis of conventional Langmiur probe. The electron density measured by microwave resonance probe is only a function of dielectric constant of plasma, there should be less or no influence of electronegative or reactive plasma. In this paper, a floating microwave resonator probe is proposed to measure electron density of capacitively coupled Ar plasma. A comparison with Langmuir double probe measurement shows that microwave resonance probe is applicable for measuring low electron density of plasma. The experimental results from the measurements of Ar/SF6 and SF6/O2 capacitively discharge driven by 40.68 MHz show that addition of SF6 into Ar plasma reduces the electron density significantly, with further increase of SF6 flow rate, electron density shows a gradual decrease. While for the addition ofO2 into SF6 discharge, the electron density continuously decreases with the increase ofO2 flow rate. Additionally, the electron density does not vary with lower frequency input power for SF6/O2 capacitively discharge driven by 40.68 MHz/13.56 MHz. The preliminary interpretations of the above experimental phenomena are presented.
Study on the mechanism of Hall effect thruster discharge with bistable state
Authors: Han Ke  , Jiang Bin-Hao  , Ji Yan-Chao  ,   School of Computer and Information Engineering, Harbin University of Commerce, Harbin 150028, China;,   School of Electrical Engineering and Automation, Harbin Institute of Technology, Harbin 150001, China
Published: December 2020

Experimental results indicate that there exist two stable discharge operation points in a self-excited mode Hall effect thruster. During the operation, the discharge operation point jumps to and fro between two values, which greatly influences the physical process of plasma discharge in the thruster channel and the comprehensive performance of thrusters. In this paper, by using the relationship between discharge magneto-ampere characteristic curve and magnetic field coil current curve, we propose the physical mechanism of forming the discharge bistable characteristic. On the basis of the mechanism, a method of stabilizing the single discharge operation point is presented through changing the slope of magnetic field coil current curve. The physical explanation is given through established one-dimensional dynamic fluid model for self-excited mode, and the results are approved by the self-excited experiment.
Plasma parameters of square superlattice pattern in a dielectric barrier discharge
Authors: Chen Jun-Ying  , Dong Li-Fang  , Li Yuan-Yuan  , Song Qian  , Ji Ya-Fei  ,   College of Physics Science and Technology , Hebei University, Baoding 071002, China
Published: December 2020

Dielectric barrier discharge is an important method of producing nonequilibrium low-temperature plasma. Measurement of the plasma parameters is highly valuable for its industrial application. Plasma parameters of square superlattice pattern are investigated by optical emission spectroscopy in a dielectric barrier discharge by using a two-liquid-electrode dielectric barrier discharge device in argon at atmospheric pressure. It is found that the light intensity of the large diameter microdischarge channel(big dot) is different from that of the small diameter channel (small dot). Vibrational temperature is investigated by using the N_{2} second positive spectrum. Electronic excitation temperature is measured by means of spectral line intensity ratio. Electron density is obtained by using the stark broadening of Ar atom 696.54 nm spectral line. The results show that the electron density and the vibrational temperature of the small dot are larger than those of the big dot but the electronic excitation temperature is lower than that of the big dot. It is suggested that the plasma state of the big dot is different from that of the small dot in the stable square superlattice pattern.
Experiment progress of ablative Rayleigh-Taylor instability based on X-ray framing camera
Authors: Cao Zhu-Rong  , Miao Wen-Yong  , Dong Jian-Jun  , Yuan Yong-Teng  , Yang Zheng-Hua  , Yuan Zheng  , Zhang Hai-Ying  , Liu Shen-Ye  , Jiang Shao-En  , Ding Yong-Kun  ,   Research Center of Laser Fusion, Chinese Academy of Engineering Physics, Mianyang 621900, China
Published: December 2020

Using high dynamic range X-ray framing camera, the radiation driven ablative Rayleigh-Taylor instability facing backlight radiography on SHENGUANH (SG) II device is studied. In the SG II that has eight beams with the 2 ns laser pulse and the ninth beam for Mo backlight, two-dimensional space-time ablation RT growth process for the cycle 20 m and the initial perturbation 1 m are observed clearly, and the non-linear growth process is also observed by the doping Br ratio of 1.1% in samples. The result lays a good foundation for quantitative characterization and numerical simulation of RT instability in inertial confinement fusion (ICF) experiments.
Theoretical prediction of the growth and surface structure of platinum nanoparticles
Authors: Chen Xi  , Lin Zheng-Zhe  , Yin Cong  , Tang Hao  , Hu Yun-Cheng  , Ning Xi-Jing  ,   Applied Ion Beam Physics Laboratory, Key Laboratory of the Ministry of Education, Institute of Modern Physics, Fudan University, Shanghai 200433, China;,   Alternative Energy and Power Generation Technology Institute, Dongfang Electric Corporation Central Academy, Chengdu 611731, China
Published: December 2020

The surface structure of platinum nanoparticle in a fuel cell is the key factor to determine the catalytic efficiency. In this paper, we apply our recently established condensation potential model [2009 Acta. Phys. Sin. 58 3293; 2009 J. Chem. Phys. 130 164711] to predict the surface structure of platinum nanoparticle, and the reliability of the model is verified by molecular dynamics simulations. By first-principles calculations based on this model, we show that for various shapes of platinum particles the surfaces are mainly composed of fcc (111) facets (about 80%), and the ratio of (100) faces is about 10%. The results are consistent with existing experimental observations. Owing to the simplicity of the calculations, this condensation potential model is widely used to predict the surface structure of common nanoparticles.
Electronic structures and optical properties of transition metals (Fe, Co, Ni, Zn) doped rutile TiO2
Authors: Zhang Xiao-Chao  , Zhao Li-Jun  , Fan Cai-Mei  , Liang Zhen-Hai  , Han Pei-De  ,   College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan 030024, China;,   College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024, China
Published: December 2020

The geometric structures of transition metals (Fe, Co, Ni and Zn) doped rutile TiO2 are studied using the first-principles method based on the density functional theory. The lattice parameters, the electronic energy band structure, and the optical properties are calculated and discussed. The results show that the errors between calculated and experimental values of lattice parameters are less than 3.6%. Appropriate dopants of transition metal ions not only influence the band structure of rutile TiO2 system and broaden the scope of light absorption, but also play an important role in trapping electrons, improving the effective separation of electronic-hole pair and enhancing light absorption ability. The optimum Fe, Co, Ni, Zn doped rutile TiO2 systems in theory are Ti0.75Fe0.25O2, Ti0.75Co0.25O2, Ti0.75Ni0.25O2, Ti0.17Zn0.17O2, respectively. The 3d orbits of Fe, Co, Ni split into two groups of energy bands, t2g and eg states contribute to the higher level of valence band and the lower level of conduction band, respectively, which is conducive to the generation of electronic-hole pair and the enhancement of photocatalytic performance of rutile TiO2. Zn 3d orbit is completely filled with electrons, and the electrons are hardly excited, so the photocatalytic activity of rutile TiO2 is not obviously improved.
Thermomagnetic power generation performance of first-order phase transition material Mn1.2Fe0.8P0.4Si0.6
Authors: Bi Li-Ge  , O. Tegus  , Yi Riletu  , Shi Hai-Rong  ,   Inner Mongolia Key Laboratory for Physics and Chemistry of Functional Materials, Inner Mongolia Normal University, Hohhot 010022, China
Published: December 2020

In this paper, we report on the magnetism and the thermomagnetic power generation performance of a first-order phase transition material Mn1.2Fe0.8P0.4Si0.6,which can be used for thermomagnetic power generation that turns heat directly into electricity. The compound is synthesized by using the high-energy ball milling and solid state reaction method. Magnetic measurements show that the compound undergoes a ferromagnetic-to-paramagnetic first-order phase transition at 337 K, accompanied by a giant magnetization change. According to this feature of the material, we design a demonstration device for thermomagnetic power generation, and study the electric current generated by heat induced phase transition. The current increases with the increase of the heat-flow temperature and the mass of material. This study shows that the Mn1.2Fe0.8P0.4Si0.6 compound possesses the high performance of thermomagnetic power generation.
Electronic transport in hybrid contact of doubly-stacked zigzag graphene nanoribbons
Authors: Hu Fei  , Duan Ling  , Ding Jian-Wen  ,   Department of Physics & Institute of Nanophysics and Rare-earth Luminescence, Xiangtan 411105, China;,   Key Laboratory of Low Dimensional Materials & Application Technology, Xiangtan University, Xiangtan 411105, China
Published: December 2020

According to a tight-binding model and the Green's function formalism, we investigate the electronic transport in hybrid contact of doubly stacked zigzag graphene nanoribbons. Our study shows that the next nearest neighbor interlayer coupling, the hybrid contact length and gate voltage each have a significant modulation effect on the electron transmission spectrum. Due to the next nearest neighbor interlayer coupling, the transmission spectrum of the hybrid contact exhibits an electron-hole asymmetry, which is consistent with the experimental result. There exist some transmission gap (T=0) and quantum step (T=1) within the first subband below the Fermi energy, meaning that electrons can reflect and/or transmit completely. It is also observed that the transmission coefficient oscillates within 1 as the contact length increases, showing a quantum interference effect. Under a gate voltage in the bilayer regime, the transmission coefficient can be changed from 1 to 0, showing that a switching effect exists here. The results is useful for the design and the application of the graphene-based device.
Investigation on Schottky contacts in organic thin film photovoltaic devices by transient photocurrent
Authors: Li Bo  , Shao Jian-Feng  ,   Department of Applied Physics, College of Science, Zhejiang University of Technology, Hangzhou 310023, China
Published: December 2020

The organic thin film photovoltaic device with a structure of tin indium oxide (ITO)/organic semiconductor/metal is fabricated. A rectifying behavior of the device is observed from the current-voltage characteristics. However, it is hard to judge the direction of internal electric field between the organic semiconductor and electrodes under Schottky contacts. In order to investigate the characteristics of Schottky contacts between the organic semiconductor and electrodes, the devices with the structures of ITO/organic insulator layer/organic semiconductor/metal and ITO/organic semiconductor/organic insulator layer/metal are fabricated. It is easy to judge the direction of internal electric field between the organic semiconductor and electrodes under Schottky contacts by the direction of transient photocurrent which is produced under the irradiation from the modulated laser. The correctness of judgement is further proved by the change of transient photocurrent intensity with a bias voltage applied.
Study on the crossover of static dielectric constants of liquids with temperature and the relevant correlations
Authors: Zhang Li-Li  , Huang Xin-Ru  , Zhou Heng-Wei  , Huang Yi-Neng  ,   Xinjiang Laboratory of Phase Transitions and Microstructures in Condensed Matter Physics, Physical College of Science and Technology, Yili Normal University, Yining 835000, China;,   National Lab of Solid State Microstructures, College of Physics, Nanjing University, Nanjing 210093, China;,   Department of Physics, Shihezi University, Shihezi 832003, China
Published: December 2020

In order to induce the general behaviors of the orientation correlations between molecules from the variation of static dielectric constant of liquid with temperature, we filtrate the experimental data of 18 kinds of liquids with the contribution of the electronic polarizations much smaller than that of the orientation correlations between molecules from the present references. The results indicate that there is a universal crossover for the varication of the static dielectric constants of the liquids with temperature, and for such a kind of crossover, there exist at least two kinds of orientation correlation orders between molecules, one increases but the other decreases with temperature.
Preparation and emission characteristic study of plasma-sprayed scandia-doped oxide cathode
Authors: Zhang Min  , Wang Xiao-Xia  , Luo Ji-Run  , Liao Xian-Heng  ,   Key Laboratory of High Power Microwave Sources and Technologies, Institute of Electronics, Chinese Academy of Sciences, Beijing 100190, China;,   Graduate University of Chinese Academy of Sciences, Beijing 100049, China
Published: December 2020

Plasma-sprayed scandia-doped oxide cathode is prepared by doping a small amount of scandia into the triple carbonates and employing the air plasma spraying technique. In the preparation process, a small amount of scandia is added in the shaping process of mixing the triple carbonates with an additional 12%22% of BaCO3 (molar ratio). The shape and the distribution of the feed material analyzed by using scanning electron microscope show that the size and the shape of the feed material meet the requirement for plasma-spraying and that it fully compensates the loss of barium in the plasma-spraying process. The analysis of the decomposition process shows that scandia-doped plasma-sprayed oxide cathode has a shorter process of decomposition and less exhausted gas amount than the commonly-used oxide cathode. The test on the emission performance of the new type oxide cathode shows that the emission performance of scandia-doped plasma-sprayed oxide cathode is much better than that of commonly-used oxide cathode and that the life time of the former is longer than that of the latter.
Preparation and investigation of the formation mechanism of organic single crystal nanostructures of PTCDA
Authors: Han Yu-Yan  , Cao Liang  , Xu Fa-Qiang  , Chen Tie-Xin  , Zheng Zhi-Yuan  , Wan Li  , Liu Ling-Yun  ,   National Synchrotron Radiation Laboratory, School of Nuclear Science and Technology, University of Science and Technology of China, Hefei 230029, China
Published: December 2020

Different types of nanostructures of an organic dye compound, perylene-3,4,9,10-tetracarboxylic-dianhydride (PTCDA), are prepared on anodic alumina oxide (AAO) at different values of substrate temperature (Ts) by a facile physical vapor deposition (PVD) method in a molecular beam epitaxy (MBE) system. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM) and selected area electron diffraction (SAED) techniques are applied to the systematical characterization of the nanostructures. It is found that the PTCDA nanofibers, nanoneedles, nanobelts, and nanorods are produced at 330 ℃Ts; Only nanorods are formed at 280 ℃, 230 ℃, and 180 ℃, and their lengths become short asTs decreases; the continuous films are obtained on 50 ℃ AAOs substrates. HRTEM and SAED results show that the nanoneedle and nanorods are of single crystal. According to SEM results, the formation of PTCDA nanostructures should be mainly affected by surface curvature andTs.
Analytical modeling of asymmetric HALO-doped surrounding-gate MOSFET with gate overlapped lightly-doped drain
Authors: Li Cong  , Zhuang Yi-Qi  , Han Ru  , Zhang Li  , Bao Jun-Lin  ,   Key Laboratory for Wide Band-Gap Semiconductor Materials and Devices, School of Microelectronics, Xidian University, Xi'an 710071, China;,   Aviation Microelectronics Center, Northwestern Polytechnic University., Xi'an 710072, China
Published: December 2020

A novel asymmetric HALO-doped surrounding-gate MOSFET with gate overlapped lightly-doped drain is presented. The performance of the new structure is studied by developing physics-based analytical models for surface potential, threshold voltage, and subthreshold current. It is found that the new structure can effectively suppress the short-channel effects and the hot-carrier effects, and simultaneously reduce the off-state current. It is also revealed that subthreshold current is a slight function of doping concentration of overlapped region, while work-function of gate electrode has a strong influence on subthreshold current. The accuracy of the analytical model is verified by its good agreement with the three-dimensional numerical device simulator ISE.
The practical security and performance analysis of the quantum data stream cipher system by the αη protocol
Authors: Lu Yuan  , Huang Peng  , Zhu Jun  , Dai Wen-Chao  , Zeng Gui-Hua  ,   State Key Laboratory of Advanced Optical Communication Systems and Networks, Shanghai Jiaotong University, Shanghai 200240, China
Published: December 2020

The αη protocol is the random cipher protocol and hides information by the quantum phase noise. In this paper, the security criterion of the protocol is deduced by developing a quantum channel model and calculating the amount of information obtained by the eavesdropper. The results show the security of the protocol depends mainly on the average photon number of the signal quantum states and the number of cipher-text symbols. Considering the above factors, the secure value region of the average photon number and cipher-text symbol number is calculated, which is against the beam splitter attack. Furthermore, the effective communication distance is simulated.
Variable space scale factor spherical coordinates and time-space metric
Authors: Bian Bao-Min  , Lai Xiao-Ming  , Yang Ling  , Li Zhen-Hua  , He An-Zhi  ,   Department of Information Physics and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
Published: December 2020

The time-space metric is a fundamental concept of general relativity, and it is the logical foundation of cosmology and astrophysics. A time-related space scale factor is introduced into a 4-dimensional time-space interval model. The transformations among the flat metric, the Schwarzschild metric and the Robertson-Walker (R-W) metric are obtained in spherical coordinate system. Based on the time-space interval of the time-related scale factor coordinate, the solutions of R-W metric with parameter k=1 and the non-vacuum metric outside stars are deduced. A new point of view is advanced to comprehend the modern physical non-flat time-space.
The analysis of stochastic resonance of periodic signal with large parameters
Authors: Yang Ding-Xin  , Hu Zheng  , Yang Yong-Min  ,   College of Mechatronics Engineering and Automation, National University of Defense Technology, Changsha 410073, China
Published: December 2020

It is of significance in engineering to achieve stochastic resonance of periodic signal with large frequency by turning the parameters of a bistable system. The normalization transform of bistable system parameter is deduced. Stochastic resonance of periodic signal with large parameters is exhibited by numerical simulation based on the proposed normalization transform, by which an arbitrary high frequency periodic signal can be processed. Analog circuit is used to verify the stochastic resonance happening in the bistable system with large parameters. The mechanism of realizing a periodic signal with large parameters by twice sampling stochastic resonance is analyzed, which is compared with normalization transform method through numerical simulation. The simulation results show that the numerical solution of twice sampling stochastic resonance is prone to being unstable with the variation of mixed input signal amplitude, while the normalization transform method possesses more stability and adaptability.
Chaotic time series prediction based on wavelet echo state network
Authors: Song Tong  , Li Han  ,   Faculty of Electronic Information and Electrical Engineering, Dalian University of Technology, Dalian 116023, China
Published: December 2020

Chaos is widespread in nature and human society, so the prediction of chaotic time series is very important. In this paper, we propose a new chaotic time series prediction model echo state network based on wavelet, which can effectively overcome the ill-posed problem that exists in traditional echo state networks. And it also has a good generalization ability. Three time series are used to test the new model, i.e., Lorenz time series, Lorenz time series with added noise and batch reactor vessel temperature time series. Results suggest that the new proposed method can achieve a higher predictable accuracy, better generalization and more stable prediction results than traditional echo state networks.
Theoretical investigation of orthogonal dual-pump four-wave mixing in semiconductor optical amplifier
Authors: Li Pei-Li  , Shi Wei-Hua  , Huang De-Xiu  , Zhang Xin-Liang  ,   College of Optoelectronic Engineering, Nanjing University of Posts and Telecommunications, Nanjing 210046, China;,   Department of Optoelectronic Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
Published: December 2020

A comprehensive broad-band model of orthogonal dual-pump four-wave mixing (FWM) in semiconductor optical amplifier (SOA) is presented in the case of the polarization state of the input signal being arbitrary. By performing numerical simulation and taking the all-optical wavelength conversion based on orthogonal dual-pump FWM in an SOA for example, the effects of the input light powers, frequency detuning and polarization state of the input signal on the orthogonal dual-pump FWM and the performances of wavelength conversion are theoretically investigated.
Sol-gel co-assembly of inverse opal film and research on its optical properties
Authors: Ni Hai-Bin  , Wang Ming  , Chen Wei  ,   Key Laboratory on Opto-Electronic Technology of Jiangsu Province, School of Physics Science and Technology, Nanjing Normal University, Nanjing 210046, China
Published: December 2020

The method of sol-gel co-assembling high quality, large area silica inverse opal films is studied. Hydrolyzed sol-gel precursor solution is added in monodisperse polystyrene (PS) colloidal solution to co-assemble composite colloidal crystal film which is infiltrated with silicate gel simultaneously. PS colloidal crystal template is removed by calcining the composite colloidal crystal film to obtain the silica inverse opal film. Silica inverse opal films of different pore sizes are fabricated by this method after researching the ratio of added hydrolyzed sol-gel precursor solution, the temperature of vertical evaporation, and the sinter temperature. The structures and the elements of fabricated silica inverse opal films are characterized by scanning electron microscope and X-ray energy spectrometer, and their optical transmission spectra are measured. Research results indicate that silica inverse opal films fabricated by sol-gel co-assembly method are highly ordered in large area, and the pore sizes are controllable in a wide range; measured transmission spectra show an evident band-gap, whose central wavelength is coincident with calculated result.
Experimental study of interaction between bubble and free surface
Authors: Zhang A-Man  , Wang Chao  , Wang Shi-Ping  , Cheng Xiao-Da  ,   College of Shipbuilding Engineering, Harbin Engineering University, Harbin 150001, China
Published: December 2020

As a bubble moves near different boundaries, the motion characteristic will change largely compared with the condition of free field, especially near the free surface: there will appear a complex phenomenon because of the interaction. This paper aims to investigate experimentally the phenomenon and the regularity of the interaction between bubble and free surface. Using a spark-generated device and a high-speed camera, the influences of free surface on the maximal radius, period, jet time and width of the bubble are discussed. The relation between the voltage and the maximal radius is obtained. Different typical phenomena near the free surface are observed. The factors inducing different plume phenomena are obtained. Then the regurality of maximal height of the water column varying with dimensionless distance under the same initial condition is obtained, which provides a reference to the research on the interaction between bubble and free surface.
Bi-doped germanium niobate glasses with near-infrared broad-band emission
Authors: Zhao He-Ling  , Xia Hai-Ping  , Luo Cai-Xiang  , Xu Jun  ,   Laboratory of Photo-electronic Functional Materials, Ningbo University, Ningbo 315211, China;,   Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050, China
Published: December 2020

The Bi2O3 doped glasses with concentrations of (0.9-x) GeO2-xNb2O5-0.1BaO (x=0.04, 0.07, 0.1) glasses are prepared by the conventional melting method. The differential thermal analysis (DTA) curves, the absorption spectra, the fluorescence decay curve and the X-ray photoelectron spectra are measured. The difference between glass crystallization onset temperature and transition temperature (Tx-Tg) of the glasses is up to 200℃ from the DTA curve. Absorption peaks at 500, 700, and 1000 nm are observed. The absorption edges show a red-shift with the increase of Nb2O5 content x. The emission band at 1300 nm with the full width at half maximum near 200 nm is observed under the excitation of 808 nm laser. The fluorescence intensity increases with the increase of the concentration of Bi2O3. The fluorescence intensity reaches a maximal value when the concentration of Bi2O3 is about 0.01. The peaks of binding energy in XPS are located at 159.6 and 164.7 eV respectively. The binding energy peaks are located between those of Bi3+ and Bi5+ by comparing with those of Bi2O3 (Bi3+) and NaBiO3 (Bi5+). According to the XPS results, one may conclude that Bi3+ and Bi5+ ions co-exist in the glass. The near infrared broadband emission may be assigned to Bi5+ ion based on the results of emission spectra and X-ray photoelectron spectra. The broadband intensity is gradually weakened as the Nb2O5 content x increases from 0.04 to 0.1. As GeO2 is substituted by Nb2O5, complex NbGe defects are formed and the lower valence state of Bi ions will be inevitably formed to compensate the extra electric charge from Nb5+, thus resulting in the inhibition of Bi5+ and weakening the fluorescence aforementioned.
The effects of point-defects on the dynamic scaling of growing surfaces
Authors: Zhang Lei-Ming  , Xia Hui  ,   Xuhai College, China University of Mining and Technology, Xuzhou 221008, China;,   Department of Physics, China University of Mining and Technology, Xuzhou 221008, China
Published: December 2020

The dynamic scaling properties of growing surfaces with point-defects are studied by applying the dynamic renormalization-group approach to the noisy Kuramoto-Sivashinsky equation with an additional term of point-defects potential. From the roughness and the dynamic exponents and z obtained here it follows that point-defects tend to roughen the growing surface and shorten its dynamic relaxation process to a steady-growth state.
The first principles and experimental study on Mn-doped LiFePO4
Authors: Dou Jun-Qing  , Kang Xue-Ya  , Tuerdi Wumair  , Hua Ning  , Han Ying  ,   Xinjiang Key Laboratory of Electronic Information Materials and Devices, Xinjiang Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Urumqi 830011, China;,   Graduate University of Chinese Academy of Sciences, Beijing 100049, China
Published: December 2020

The electronic structures of pure and Mn-doped LiFePO4 are studied using density functional theory (DFT). The results demonstrate that the pure LiFePO4 has a band gap of 0.725 eV, while the 25% Mn doped LiFe0.75Mn0.25PO4 has the smallest band gap (0.469 eV), and the weakest FeO and LiO bond, which indicates that the electronic conductivity and the ionic conductivity of the doped LiFePO4 are improved due to doping. On the other hand, the experimental results also show that the LiFe0.75Mn0.25PO4 has the best electrochemical performance and it delivers a very high capacity of 158 mAh? g-1 and a high energy density of 551 Whkg-1.
Distributions of the threshold voltage and the temperature in the channel of amorphous silicon thin film transistors
Authors: Qiang Lei  , Yao Ruo-He  ,   School of Electronic and Information Engineering, South China University of Technology, Guangzhou 510640, China
Published: December 2020

Based on the double exponential distributions of trap states in the channel of the hydrogenated amorphous silicon thin film transistor, characteristic temperatures of tail state and deep state are distinguished. Besides, series resistances are used to be associated with characteristic lengths of the source and the drain with trap states. By taking advantage of the Poisson equation and Gauss theorem, the expression of the threshold voltage distribution is obtained. The results show that with the increase of the distance between the point and the source, the threshold voltage decreases. Moreover, under the degradation of the self-heating effect, the distribution of the temperature in the channel is non-uniform and its variation in the channel center is the biggest.
Preparation and characteristic study of nanometer thickness depleted uranium / Au multilayer
Authors: Yi Tai-Min  , Xing Pi-Feng  , Du Kai  , Zheng Feng-Cheng  , Yang Meng-Sheng  , Xie Jun  , Li Chao-Yang  ,   Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900, China
Published: December 2020

Modeling and experimental results show that the depleted uranium (DU) and Aucocktail nanometer multilayer will improve the X-ray conversion efficiency by reducing energy loss to penetration of the X-ray into the hohlraum wall. DU/Au multilayer plane film is deposited by magnetron sputtering through alternately rotating substrate in front of separate DU and Au sources. The geometry parameter, surface topography, atomic concentration and interface structure of DU/Au multilayer are characterized by white light interferometer, scanning electronic microscope (SEM) and X-ray photoelectron spectroscopy (XPS). Au film becomes continuous when its thickness reaches 8 nm. Combining with theoretical modeling results, 30 nm DU and 8 nm Au multilayer is chosen. The periodic thickness of DU/Au is measured to be about 37 nm. Well-defined Du/Au interface is observed by SEM. Diffusion at DU/Au interface is observed by XPS. The atomic concentration ratio of DU, Au, O is 73:26:1. The binding energy of Au 4f of 8 nm thickness Au film shifts toward high-energy tail about by 0.6 eV. Similar phenomena are unfound in 30 nm thickness DU film.
A model for releasing of stored energy and microstructure evolution during recrystallization by phase-field simulation
Authors: Zhang Xian-Gang  , Zong Ya-Ping  , Wu Yan  ,   Key Laboratory of Anisotropy Design and Texture Engineering of Materials of Ministry of Education, Northeastern University, Shenyang 110004, China;,   Department of Mathematics and Physics, Shenyang University of Chemical Technology, Shenyang 110142, China
Published: December 2020

A format of f(ik,jk ) = Es (ide )2(1-(jre )2) to express cold deformed stored energy is suggested in a phase-field model for simulating recrystallization in alloys. Using AZ31 magnesium alloy as an example, the recrystallization process is simulated by the new model, and the simulation results are in good agreement with experimental measurements. The nucleation process of recrystallization is realized for the first time by the model based on the physical background. The simulation results show that the grain growth of a cold deformed alloy in the annealing process indicates automatically two stages: recrystallization driven by the restored energy and thermal growth driven by boundary energy. A theoretical time spent in finishing recrystallization, obtained by simulation, is found to be 2/3 of that obtained by industrial practice. The mechanism and the experimental results about the influence of cold deformation on subgrain size and stored energy are examined, and the experimental results are introduced into the simulation. The common experimental phenomenon shows that there is a peak at the critical strain on the curve of recrystallized grain size versus cold strain. A theoretical explaination to the mechanism of the peak occurrence is also discussed.
Photoelectricity performance research based on the sol-modified thin film electrode of dye-sensitized solar cells
Authors: Xu Wei-Wei  , Hu Lin-Hua  , Luo Xiang-Dong  , Liu Pei-Sheng  , Dai Song-Yuan  ,   Xinglin College, Nantong University, Nantong 226019, China;,   Key Laboratory of Novel Thin Film Solar Cells, Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, China
Published: December 2020

Nanoporous film electrode is a crucial composition of dye-sensitized solar cells, which influences the photoelectric conversion performance. To improve the property of the photoelectrode, different modification methods by using different concentrations of TiO2 sol are investigated. The crystallite size and phase of the nanoporous TiO2 particles and the TiO2 sol after sintering are studied with X-ray diffraction. The microstructure morphologies of the conductive glass and the films are determined by the high resolution transmission electron microscopy and the field emission scanning electron microscopy. The influences on electron lifetime n and the electron transit time d are analyzed by intensity-modulated photocurrent spectroscopy and photovoltage spectroscopy from the mechanisms of electron transport and back reaction kinetics. It is found that the back reactions are well suppressed under dark conditions after sol modifications. n is effectively extended and d is also shorten correspondingly by any kind of sol treatment. The short-current density and the photoelectric conversion efficiency are increased by 10.9% and 11.9% separately, when 0.10 molL-1 sol modification is applied both to the conductive glass and to the nanoporous TiO2 film at the same time.
Structure evolvement of solid particles and mechano-chemical effect
Authors: Xu Bo  , Wang Shu-Lin  , Li Lai-Qiang  , Li Sheng-Juan  ,   College of Energy and Power Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China;,   College of Material Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
Published: December 2020

Al ultra-fine grains are prepared by dry roller vibration milling at room temperature. After the ultrasonic hydrolyzing, the Al powders are milled for 2 h, 4 h and 8 h, separately, becoming the colloidal Al(OH)3. After the hydrolyzing production are dried, grinded, calcined, the flaky -Al2O3 nano-particles are obtained, and the particles sizes are in the range from 30 to 50 nm. By X ray diffraction (XRD) analysis method and transmission electron microscope (TEM), we analyze the energy conversion of solid particles in the vibration milling, and study the relation between the structure evolvement of solid particles and mechano-chemical reaction, in order to ascertain ideal milling time. The research results indicate that the solid particles under the action of mechanical force generate a mass of deformation and dislocation flaws and the material is in metastable high-energy state, which is favorable for inducing mechano-chemical reaction. In certain conditions, the surface energy of crystalloid, strain and dislocation energy could be mutually converted. The odds of lattice distortion and dislocation are maximal for the 2 h-milled Al powders, so the material shows a higher chemical reaction activation. On the ultrasonic agitation, the energy is fully released from the material interior, then Al(OH)3 nano-particles are prepared in a short time.
Analysis of dynamic behavior in the digitally controlled single-phase full-bridge inverter
Authors: Lei Bo  , Xiao Guo-Chun  , Wu Xuan-Lü  ,   State Key Laboratory of Electrical Insulation and Power Equipment, School of Electrical Engineering, Xi'an Jiaotong University, Xi'an 710049, China
Published: December 2020

Considering the multiformity in the PWM modulation principle, the diversity in the structures of filter and load, and the limitation of the method based on state transition matrix in the analysis of digital controlled single-phase full-bridge inverter, we present a new method based on analytic expression of the elements in the state transition matrix. This method can analytically express the relationship between the parameters and the dynamic motion of a system named N-M digitally controlled single-phase full-bridge inverter, which has N state variables and structure changing M times within one switching cycle. As an example, the discriminant of Hopf bifurcation, the analytic expressions of the stability boundary and the oscillation frequency of a 3-3 digitally controlled single-phase full-bridge inverter are derived. Finally, the theoretical results are verified by simulations and circuit experiments.