bluuebunny/crossref_metadata_2025 huggingface dataset:
The implementation of the three-dimensional numerical simulation of the coaxial magnetically insulated transmission line with helical inductor
Authors: Liu La-Qun  , Liu Da-Gang  , Wang Xue-Qiong  , Zou Wen-Kang  , Yang Chao  ,   School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu 610054, China;,   Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang 621900, China
Published: December 2020

According to the actual device size, a three-dimensional numerical simulation model of the coaxial magnetically insulated transmission line with a helical inductor is developed. The diode with an appropriate distance between anode and cathode is selected as a load of the transmission line. Setting the device parameters, the device is simulated. Comparing the simulation results with the experimental data, the reliability of the simulation is proved. By combining with the corresponding experimental data, the transmission efficiency of the coaxial magnetically insulated transmission lines with adding the structure of helical inductor is analyzed.
The numerical simulation of the electronic energy deposition and temperature variation in post-hole convolute of magnetically insulated transmission lines
Authors: Liu La-Qun  , Liu Da-Gang  , Wang Xue-Qiong  , Yang Chao  , Xia Meng-Zhong  , Peng Kai  ,   School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu 610054, China
Published: December 2020

In this paper, we introduce the numerical simulation theory and method to achieve the energy deposition and temperature variation produced by the high-energy electron bombarding the anode surface. A simple beam launch model is developed. The accuracy of the numerical calculation of the anode surface electronic energy deposition is primarily validated. Then, selecting the magnetically insulated transmission line in post-hole convolute as a model, the energy deposition and the temperature variation in the anode produced in the process are simulated. Also by comparing the simulation results with the results given in the literature, the simulation accuracy is further proved. Finally, the simulation results are analyzed and the physical mechanism produced by the simulation results is also discussed.
The ab initio and potential energy curve of OH, OCI and HOCI(1A')
Authors: Han Xiao-Qin  , Xiao Xia-Jie  , Liu Yu-Fang  ,   Department of Physics, Henan Normal University, Xinxiang 453007, China;,   Department of Physics, Shangqiu Normal College, Shangqiu 476000, China;,   Henan Quality Polytechnic, Pingdingshan 467000, China
Published: December 2020

The possible ground state structures of OH, OCI and HOCI are optimized by using some methods included in Gaussian 09. Among them, the methods QCISD/6-311G(2df) and B3P86/6-311+G(2df) are the most suitable for the calculation of OH(X2) and OCI(X2) the spacings between eguilibrium nuclei ROH=0.09696 nm and ROCI=0.1569 nm, and harmonic freguencies (OH)=3745.37 cm-1 and (OCI)=892.046 cm-1 are calculated respectively. The calculation results are in good agreement with experimental results, Each potential energy curve obtained via scanning the single point energies of OH and OCI is well fit with the four-parameter Murrell-Sorbie function, according to which spectral data and force constants are deduced. The ground state of HOCI molecule is of 2A1' state, and the parameters of structure are ROH=0.0966 nm, HOCI 102.3, 1(a1)=738.69 cm-1, 2(b2)=1260.25 cm-1, De=2.24 eV with QCISD(T)/D95(df,pd). The present calculation results are in excellent agreement with the experimental values, and they are better than those given in the literature. And the force constants are calculated at the same time. The potential energy function of HOCI is derived from the many-body expansion theory. In the symmetric-stretch potential energy diagram, there is a saddle point in reaction channel H+OCI HOCI, and a stable HOCI molecule could be formed only when H atom crosses an energy barrier of 1.74 eV. However there is no clear energy barrier in the reaction channel Cl+OH HOCI, therefore a stable HOCI molecule can form easily.
The dynamic process of two-electron atom irradiated by intense laser pulse using time dependent quantum Monte Carlo method
Authors: Guo Fu-Ming  , Song Yang  , Chen Ji-Gen  , Zeng Si-Liang  , Yang Yu-Jun  ,   Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012, China;,   Department of Physics and Materials Engineering, College of Physics and Electronic Engineering, Taizhou University, Taizhou 318000, China;,   Science and Technology Computation Physics Laboratory, Institute of Applied Physics and Computational Mathematics, Beijing 100088, China
Published: December 2020

We investigate the electron dynamic process of a one-dimensional two-electron atom irradiated by strong laser pulse using the improved time-dependent quantum Monte Carlo (TDQMC) scheme. By comparison with the scheme for solving the time-dependent Schrdinger equation by using the accurate numerical integration, the dynamic variation of particle in a quantum ensemble, corresponding to the calculated wave-packet, is consistent with the evolution of time-dependent wavepacket. The computation efficiency of the TDQMC is more largely enhanced than that of the time-dependent integration method. According to the dynamic evolution behaviors of the calculated classical particle ensemble, we analyze the excitation, ionization, recombination of electron and other non-linear processes in a strong laser field.
Polarization induced ultra-high electron concentration up to 1020 cm-3 in graded AlGaN
Authors: Li Shi-Bin  , Xiao Zhan-Fei  , Su Yuan-Jie  , Jiang Jing  , Ju Yong-Feng  , Wu Zhi-Ming  , Jiang Ya-Dong  ,   State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, University of Electronic Science and Technology of China, Chengdu 610054, China
Published: December 2020

Carrier concentration and mobility of materials are key factors affecting device performance. Hall tests at different temperatures demonstrate that the carrier concentration and mobility in impurity-doped AlGaN decrease with temperature decreasing. However, carrier concentration and mobility obtained by polarization-induced doping are independent of temperature. Using quasi-insulating GaN as substrate, the electron concentration obtained in the linearly graded AlGaN film through impurity-doping is only 10-17 cm-3 or less. In this study, using unintentional impurity doped (n-type, 10-16 cm-3) GaN template, graded AlGaN film is grown by molecular beam epitaxial, in which polarization induced ultra-high electron concentration is up to 1020 cm-3 in graded AlGaN film without using any dopant. Using quasi-insulating GaN as substrate, only the surface of the free electrons serves as polarization dopant, while unintentionally doped GaN template is used as a substrate, in addition to free electrons on surface/interface, it is also reasonable to surmise more negative charges attracted by polarization electric field to be the source of polarization doping, in the unintentional doped GaN template, thereby achieving an ultra-high carrier concentration via polarization induced n-type doping.
Design and simulation of a cross split ring lefthanded materials unit structure
Authors: Yang Chen  , Zhang Hong-Xin  , Wang Hai-Xia  , Xu Nan  , Xu Yuan-Yuan  , Huang Li-Yu  , Zhang Ke-Xin  ,   Beijing Key Laboratory of Work Safety Intelligent Monitoring, School of Electronic Engineering, Beijing University of Posts and Telecommunications, Beijing 100876, China
Published: December 2020

In this paper, we present a novel compact left-handed material unit, which can generate the equivalent negative permittivity and negative permeability in the two-dimensional direction only by etching one side of the dielectric substrate. We propose a new formula for calculating the field and circuit to analyze the equivalent permittivity and the equivalent permeability that are used to explain the principle of the left-handed characteristic of the unit. In the simulation, the equivalent permittivity and permeability are calculated by the Nicolson-Ross-Weir method, and the negative refraction is verified by the prism experiment. The experiments show that the cross-ring structure unit can present left-handed properties with frequency bands appearing at 6.86.9 GHz in the two-dimensional incidence. The left-handed material can be used to design microwave field for its simple fabrication process.
Operation principle of optical waveguide isolator based on TE-TM mode conversion
Authors: Zeng Wei-You  , Xie Kang  , Chen Wei  , Mao Shu-Zhe  ,   School of Science, Hubei University of Automotive Technology, Shiyan 442002, China;,   School of Instrument Science and Opto-Electronic Engineering, Hefei University of Technology, Hefei 230009, China
Published: December 2020

According to the perturbation theory, the theory of self-phase compensation is developed for the optical waveguide isolator based on the TE-TM mode conversion. The operation principle of such a device is explained in terms of synchronization of phase and power conversion. The effect of balancing phase mismatches of the two convertors on achieving a proper percentage of mode conversion is revealed. The simulation results confirm the self-phase compensation theory.
Theoretical and experimental study on femtosecond enhancement resonator
Authors: Han Hai-Nian  , Zhang Jin-Wei  , Zhang Qing  , Zhang Long  , Wei Zhi-Yi  ,   Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
Published: December 2020

The femtosecond enhancement resonator has important applications in the fields of nonlinear optics, precision spectroscopy, etc. In particular, it has been become a powerful tool of generating ultraviolet optical frequency comb at a high repetition rate in recent years. In this paper, we analyze the characteristics of enhancement and dispersion in the femtosecond enhancement resonator by use of the circulating stable electric field method. The relations between enhancement multiple and fineness and between, resonance bandwidth and fineness as well as intracavity dispersion are obtained. Finally, we experimentally realize the resonance enhancement of 15 fs laser from a Ti:sapphire oscillator at a repetition rate of 175 MHz. The enhanced magnification is about 10.
Noise annoyance from a mixture of multiple single sources: rating and prediction
Authors: Yan Liang  , Chen Ke-An  , Ruedi Stoop  ,   College of Marine Engineering, Northwestern Polytechnical University, Xi'an 710072, China;,   Institute of Neuroinformatics, Swiss Federal Institute of Technology Zurich, Zurich 8057, Switzerland
Published: December 2020

In this paper, noise annoyance from a mixture of multiple single sources is studied with emphasis on subjective evaluation and objective prediction. From 10 subjects, annoyance values for all single and artificially combined noise samples are collected using the semantic differential method with a suitable verbal scale. We propose a novel method to determine the utility weights of a multivariate linear regression model by comparing the total annoyance T of the combined noise sample to every single annoyance i from its componential single sound sample. This method predicts T on the premise of given i. Our results demonstrate that the multivariate linear regression model and the calculated utility weights provide a good and conceptually simple framework to predict the total noise annoyance.
Numerical studies of unsteady ignition of pulverized magnesium particle cloud
Authors: Yang Jin-Zhao  , Xia Zhi-Xun  , Hu Jian-Xin  ,   Science and Technology on Scramjet Laboratory, College of Aerospace and Material Engineering, National University of Defense Technology, Changsha 410073, China
Published: December 2020

A one-dimensional unsteady magnesium particle cloud ignition model with finite influencing sphere is established. The behavior of ignition of magnesium particle cloud is numerically simulated. The result shows that when the reaction is speeded up on the surface of magnesium particle, the temperature of the particle phase rises rapidly up to ignition temperature, while the surrounding air is much slower in temperature rising than particles; the gas temperature rising is unconspicuous in the whole sphere in the ignition process, albeit it is significant near the particle surface. The effects of the interior parameters and the environmental parameters on the ignition of the magnesium particle cloud are analyzed. With the increase of particle concentration, the particle cloud becomes easier to be ignited, and reduction in its ignition time delay can be seen. However, when the particle concentration has increased to some specific extent and its further increase will be adverse to the ignition of the particle cloud. The influence of the environmental pressure on the ignition of particle cloud is insignificant, and the ignition performance of the particle cloud almost keeps constant in a range of 1-5 atm. The oxygen concentration in the gas phase also has a weak effect on the ignition performance of particle cloud, but when the oxygen concentration is very low, the effect will significantly increase. The particle size, the initial temperature of the gas/particle and the radiant source have all great influences on the ignition performance of the particle cloud. Small particle and high temperature are helpful for speeding up the ignition process. The tendency obtained by numerical simulation coincides well with that of the experimental results from the literature.
Experimental investigation of radiation charactristics of Ti wire X-pinch X-ray source on Yang accelerator
Authors: Zhou Shao-Tong  , Li Jun  , Huang Xian-Bin  , Cai Hong-Chun  , Zhang Si-Qun  , Li Jing  , Duan Shu-Chao  , Zhou Rong-Guo  ,   Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang 621900, China
Published: December 2020

The X-ray radiation properties of titanium wire X-pinch are investigated on the Yang accelerator at 500800 kA peak current with a rise time of about 80 ns. The radiation power, spectrum and source size of the X-pinch X-ray source are measured and analyzed using X-ray diodes, a transmission grating spectrometer, a crystal spectrometer and a slit camera. The hot dense spot smaller than 15 m emits 1 J of X-ray with an FWHM of 200 ps and a peak power of 1.5 GW distributed in the range of 14 keV. A method to efficiently generate a single X-ray pulse during the X-pinch implosion is demonstrated. The X-pinch presented here is useful for imaging the early stage interior structure of Z pinch as a backlight source.
The study of capacitively-coupled hydrogen plasma at very high frequency
Authors: Li Yan-Yang  , Yang Shi-E  , Chen Yong-Sheng  , Zhou Jian-Peng  , Li Xin-Li  , Lu Jing-Xiao  ,   Key Laboratory of Materials Physics of Ministry of Education, School of Physical Engineering, Zhengzhou University, Zhengzhou 450052, China
Published: December 2020

In the high rate deposition of device grade microcrystalline silicon films and their solar cells, plasma enhanced chemical vapor deposition excited using very high frequency (VHF) has become a mainstream method. Although, great breakthroughs in the experiment are achieved, the depositional mechanism is still a research hot spot and difficulty point. In this paper, the capacitively-coupled hydrogen plasma discharge at VHF is simulated. A two-dimensional, time-dependent axial symmetry model is adopted at a frequency of 75 MHz, and the influences of pressure and plasma power on hydrogen plasma characteristic are simulated. At the same time, the hydrogen plasma is monitored on-line using the optical emission spectrometry in experiment. The results show that the value of the electronic concentration ne takes a maximum in the middle of the plasma bulk, while the electron temperature Te and the number densities of Hα and Hβ each have a maximal value at the place near the sheath and plasma bulk; the potential decreases with pressure increasing from 1 Torr to 5 Torr, the electron concentration in the plasma bulk first increases with the increase of pressure, then decreases with the further increase of pressure, but the electron temperature first decreases and then keeps stable in plasma bulk; the electron concentrations, Hα and Hβ increase linely with power increasing from 30 W to 70 W, but the electron temperature keeps stable. The experimental results and simulation results are in good agreement.
Bootstrap percolation on bipartite networks
Authors: Wan Bao-Hui  , Zhang Peng  , Zhang Jing  , Di Zeng-Ru  , Fan Ying  ,   Department of Systems Science, School of Management, Beijing Normal University, Beijing 100875, China;,   School of Science, Beijing University of Posts and Telecommunications, Beijing 100876, China
Published: December 2020

Bootstrap percolation was first used in statistic physics to study the phenomenon that magnetic-order goes down and disappears because of the disturbance of nonmagnetic impurity. With the development of complex network, the application of bootstrap percolation in network has attracted much attention. In the real world, many systems naturally exhibit the two-branch structure. And bipartite network is one of important networks in complex networks. In this paper, we use the dynamics equation and computational simulation to study the bootstrap percolation in bipartite networks. The parameters we focus on are the node initial active ratios f1 and f2 and active thresholds Ω1, and Ω2. We draw the conclusion that the ratio of active nodes has discontinuous transition, which will gradually disappear with parameters varying. We also prove the consistency between the dynamic equation and simulation results.
Theoretical analysis on the upper critical field of superconductor NbS2
Authors: Huang Hai  , Lu Yan-Yan  , Wang Wen-Jie  ,   Mathematics and Physics Department, North China Electric Power University, Beijing 102206, China
Published: December 2020

From the two-band Ginzburg-Landau theory, we study the temperature dependence of upper critical field on the layered superconductor NbS2. The temperature dependence of the anisotropic parameter for upper critical filed is also obtained. All the results fit the experimental data well in a broad temperature range. Thus our results show strong evidence that two-gap scenario is better to account for the superconductivity of NbS2. The anisotropic parameter of the upper critical field for NbS2 starts to decrease from 5.0 K, and this behavior is similar to those of MgB2 and NbSe2. However for NbS2 this number is about 7.3, which is much greater than the ones in MgB2 and NbSe2. The results also show that the band with the larger gap exhibits that the effective mass ratio between the in-plane and out-of-plane direction is about 54, and the other band indicates that the effective mass ratio is almost isotropic.
Ferromagnetic resonance phenomenon of magnetic thin film under a perpendicular field
Authors: Gu Wen-Juan  , Pan Jing  , Hu Jing-Guo  ,   College of Physics Science and Technology, Yangzhou University, Yangzhou 225002, China
Published: December 2020

Regarding ferromagnetic resonance frequency as a function of the perpendicular external magnetic field, the ferromagnetic resonance phenomenon is investigated. The results show that for the case where the external magnetic field is parallel to the its plane and the magnetic thin film has a perpendicular uniaxial magnetiocrystalline anisotropy, magnetic resonance frequency is divided into two categories, i.e., low frequency branch and high frequency branch, their specific relation depends on the magnetic anisotropy of the magnetic film; when external magnetic field is perpendicular to the systemic plane, the magnetic resonance frequency displays only a branch with the change of external magnetic field. In general, the magnetic resonance frequency decreases with the increase of the external magnetic field nonlinearly and monotonically. However, when the ratio between the cubic magnetocrystalline anisotropic field Hk1 and uniaxial magnetocrystalline anisotropic field Ha is about 2/3 Hk1/Ha < 1, the magnetic resonance frequency increases with the increase of external magnetic field, which is in good agreement with the experimental results. The results show that through magnetic resonance spectrum, the vertical magnetic anisotropy in magnetic thin film can be distinguished.
Effect of Pt spacers on interface exchange coupling in ferromagnetic/antiferromagnetic bilayers
Authors: Wang Yi-Jun  , Liu Yang  , Yu Guang-Hua  ,   School of Materials Physics and Chemistry, University of Science and Technology Beijing, Beijing 100083, China
Published: December 2020

By inserting a Pt spacer between ferromagnetic (FM)/antiferromagnetic (FeMn) coumpling systems or by doping Pt element in the AFM layer, the depth dependence of Pt spacer and the thickness dependence of Pt doping layer on exchange bias (Hex) and coercivity (Hc) are investigated. The results indicate that the number of uncompensated spin moments (UCSs) of NiFe/FeMn(dPt)/Pt/FeMn increases as a result of inserting Pt spacer, which enhances Hex and Hc of the system. Also, the distribution depth about 1.3 nm of UCS of FeMn in NiFe/FeMn system is inferred. Besides, by doping Pt element in FeMn near the FM/FeMn interlayer, we find that the Hex of the system is enhanced efficiently, which is caused by the huge increase of the number of UCSs in the system.
Research on enhanced perpendicular magnetic anisotropy in CoFe/Pd bilayer structure
Authors: Zhu Yun  , Han Na  ,   College of Physics and Electronic Information Science, Tianjin Normal University, Tianjin 300387, China
Published: December 2020

A series of CoFe/Pd bilayer thin films is fabricated by introducing a native oxide layer to the interface or to the inside of CoFe layer in this paper. The results indicate that the magnetic anisotropy of the film is transformed from in-plane to out-of-plane after annealing by introducing the native oxide layer. For the samples with the introduction of native oxide layer into CoFe layer, the strong perpendicular magnetic anisotropy is maintained in a wide range of the effective thickness (1.22 nm) of magnetic layer. For the perpendicular magnetic films, the thickness of CoFe layer in this special bilayer structure is at least 1.4 nm, thicker than in common CoFe/Pd multilayer structure. The results in this paper are beneficial for the fabrication of the electrodes in perpendicular magnetic devices with high thermal stability.
Study on magnetic domain deflection in Tb0.3Dy0.7Fe2 alloy
Authors: Li Li-Yi  , Yan Bai-Ping  , Zhang Cheng-Ming  , Cao Ji-Wei  ,   Institute of Electromagnetic and Electronic Technology, Harbin Institute of Technology, Harbin 150001, China
Published: December 2020

The characteristics of magnetic domain deflection and permeability under piezomagnetic and magnetoelastic effects in Tb0.3Dy0.7Fe2 alloy are studied in this paper. Based on the minimal value principle of Stoner-Wolhfarth model, the curve of free energy versus domain deflection angle is analyzed, and the angle deflections of magnetic domain under differ compressive stresses and magnetic fields are discussed. The calculational and experimental results of permeability under stress and magnetic field loads are used to confirm the analysis of domain deflection in ally. These results indicate that the magnetic domains [111] and [111] each have a transition effect of angle deflection with the increase of stress and magnetic field, which can be used to explain the huge magneticostrictive mechanism of Terfenol-D. Also, permeability has a negative relation with stress and magnetic field, and the influence of magnetic energy on permeability is greater than the stress energy effect, especially under small loads. The experimental results of permeability are in a good agreement with the calculations confirming the validity of calculation and analyzsis. The above computations have a significant guidance for analyzing and studying the magnetic domain deflection model and hysteresis in Terfenol-D.
A molecular dynamics study of silica cluster cutting single crystalline silicon asperity
Authors: Si Li-Na  , Guo Dan  , Luo Jian-Bin  ,   State Key Laboratory of Tribology, Tsinghua University, Beijing 100084, China
Published: December 2020

The molecular dynamics simulation method is used to study the process of silica particle cutting the roughness surface at various cutting depths. The conditions of the asperity and the particle, force bearing state of particle, the distributions of coordination number and temperature in the asperity are investigated. The simulation results show that the material removal rate is small when the cutting depth is smaller than 0.5 nm, and the removed atoms sticking to the silica particle are in single atom or atom cluster form. When the cutting depth is larger than 1 nm, the material removal rate becomes larger; meanwhile a larger scrap is formed. The crystalline silicon is converted into a locally ordered transient structure which is similar to Si-Ⅱ and Bct5-Si with the increases of temperature and pressure in the cutting process; then the transient structure forms amorphous silicon directly as the temperature and pressure decrease after the cutting process.
Effect of light path folding on the properties of electron transport in dyesensitized solar cell
Authors: Liu Wei-Qing  , Kou Dong-Xing  , Hu Lin-Hua  , Dai Song-Yuan  ,   Key Laboratory of Novel Thin Film Solar Cells, Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, China;,   Key Laboratory of Nondestructive Testing of Ministry of Education, School of the Testing and Photoeletric Enginering, Nanchang Hangkong University, Nanchang 330063, China
Published: December 2020

In this paper, an electron continuity equation with light path folding is developed based on the reflection structure of photoanode in a dye sensitized solar cell (DSC). The characteristics of modulated photocurrent frequency response are calculated, and the effects of light path folding on electron transport property are studied under different absorption and reflection conditions. Intensity modulated photocurrent spectroscopy measurements show that the established model reflectes the actual characteristic of the response to modulated photocurrent frequency when the light path is folded inside the DSC. The kinetic of electron transfer process depends on the light absorption coefficient, film thickness and large particle reflection ability and other factors in DSC with reflector structure. The deep trap is filled and residence time of electron in trap is shortened. It is attributed to the fact that the light path folding reduces the effect of trap/detrap and accelerates the electron transportation.
Influence of structure parameters on the performance of p-i-n InGaN solar cell
Authors: Zhou Mei  , Zhao De-Gang  ,   Department of Physics, China Agriculture University, Beijing 100083, China;,   State Key Laboratory on Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
Published: December 2020

The effect of structure parameters on the performance of p-i-n InGaN solar cell is investigated by theoretical calculation. It is found that the short-circuit current decreases while the open-circuit voltage increases with the increase of bandgap of InGaN material. The maximal energy conversion efficiency of p-i-n homojunction InGaN solar cell can be obtained when the bandgap of InGaN is around 1.5 eV. It is also found that the energy conversion efficiency can be improved by appropriately increasing bandgap of p-InGaN p-i-n heterojunction InGaN solar cell, in addition, the efficiency of p-i-n heterojunction InGaN solar cell may be increased further by employing the back electric filed structure. The simulation results suggest that performance of InGaN solar cell can be improved by employing p-i-n heterojunction structure if the appropriate bandgaps of p-InGaN and n-InGaN are adopted.
The lysogeny/lysis switch and entropies of stationary states in λ phage
Authors: Feng Wei  , Ding Hui  , Lin Hao  , Luo Liao-Fu  ,   Key Laboratory for Neuro Information of Ministry of Education, Center of Bioinformatics, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 610054, China;,   Laboratory of Theoretical Biophysics, School of Physical Science and Technology, Inner Mongolia University, Hohhot 010021, China
Published: December 2020

The system of Escherichia coli infected by λ phage is one of the templates for quantitative study of regulated networks. In this article, according to the characteristics of the interactions between operators and regulators, the probabilities of regulators binding to operators are described by thermodynamic partition function. On the basis of bifurcation analysis of this regulated network, the entropies of stationary states are calculated. Results show that the entropies of both lysogenic state and lytic state are lower than those of saddle-point and bifurcation point states. Moreover, we find that the lysogenic state has lower entropy than lytic state, which proves that the lysogenic state has a higher biological order.
Latitudinal distribution of landing tropical cyclones over mainland China
Authors: Zhang Han  , Guan Yu-Ping  ,   State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China;,   Graduate University of Chinese Academy of Sciences, Beijing 100049, China
Published: December 2020

Landfall location is an important research topic in studies of tropical cyclones. For tropical cyclones that made landfall over mainland China during 1951-2010, in this work, we analyze the temporal variations in the annual landfall frequency. We first study the distribution and temporal variations in the landing latitude. To avoid the inaccuracy associated with using a single dataset, in this work we adopt three best track datasets from China, the USA, and Japan and summarize meaningful common phenomena in the three datasets: the annual landfall frequency of tropical cyclones over mainland China in the Chinese dataset is 1 more than in the other two datasets on average. Since 1970, the landfall frequency in the three datasets has shown little change, whereas the landfall latitude has shown a relatively consistent northward movement (prior to 1970, the three datasets showed different trends in frequency and latitude). The landfall frequency data, assigned to different latitude bins, show that the most tropical cyclones made landfall below 30N and that landfall frequency decreased with latitude increasing. An anomalously large (small) number of tropical cyclones made landfall over the latitude zone of 21N-23N (23N-24N and 20 N-21N).
Multi-parameter fusion applied to road traffic condition forecasting
Authors: Ma Qing-Lu  , Liu Wei-Ning  , Sun Di-Hua  ,   College of Computer Science, Chongqing University, Chongqing 400044, China;,   College of Automation, Chongqing University, Chongqing 400044, China;,   Key Laboratory of Dependable Service Computing in Cyber Physical Society, Ministry of Education, Chongqing 400044, China
Published: December 2020

In view of the chaotic characteristic in road traffic flow and the actual traffic condition that cannot be comprehensively reflected by single traffic parameter, a fusion algorithm of multi-parameters for traffic condition forecasting, with the consideration of the relationship between multiple parameters, is proposed. This algorithm is based on the reconstruction of phase space. According to Bayesian estimation theory, the multiple traffic parameters are optimally fused into phase points in the same phase space. Accordingly, the phase space information increases and the phase points are closer to dynamical behavior of the traffic system. On the basis, by using the multi-parameter chaos prediction method, the tendency of dynamic systems from different aspects is described, with reference to the method of predicting single parameter chaotic time series. The experimental results confirm that more features of real traffic condition are reflected by fusing multiple traffic parameters. The multi-parameters forecasting algorithm reduces the prediction error and improves the equalizer coefficients compared with the results generated from single parameter prediction. That is to say, the prediction method used in this paper is effective and accurate for predicting traffic condition based on multiple traffic parameters.
Fabrication and characterization of single Nb/NbxSi1-x/Nb Josephson junction for voltage standard
Authors: Cao Wen-Hui  , Li Jin-Jin  , Zhong Qing  , Guo Xiao-Wei  , He Qing  , Chi Zong-Tao  ,   National Institute of Metrology, Beijing 100013, China;,   Qingdao University, Qingdao 266003, China
Published: December 2020

The core device of Modern programmable Josephson voltage standard is Josephson junction array. The most advantageous Josephson junction array is Nb/NbxSi1-x/Nb material array. The advantages of Nb/NbxSi1-x/Nb material Josephson junction are that three-layer film production process is simple, Nb and NbxSi1-x etching processes are the same and NbxSi1-x potential barrier layer components can be easily adjusted. In this paper, we investigate the NbxSi1-x/Nb single Josephson junction in National Institute of Metrology. Through measuring the dc current-voltage characteristics under low temperature (4.2 K), superconducting tunneling current and a zero voltage state jumping to voltage state are observed clearly, finally the measurement results are discussed. The work is the first study on Nb/NbxSi1-x/Nb single Josephson junction in China.
Free particle geodesic affine parameter time-space coordinate systems
Authors: Bian Bao-Min  , Lai Xiao-Ming  , Yang Lin  , Li Zhen-Hua  , He An-Zhi  ,   Department of Information Physics and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
Published: December 2020

Taking the time-series t as independent variable, the parameter equations {Xi(t)} of free particle space geodesic can be given. By transforming affine parameter R(t) we achieve homogeneous geodesic differential equations, and derive the first-order differential equations which are satisfied by affine parameter R and the sequence of analytical solutions R marked by rational number Cu. In light of R we define the distance unit of flat four-dimensional coordinate system {t,r,θ,φ}, and then establish a free particle geodesic affine parameter time-space coordinate system {t,ξ,θ,φ}. By the study of the diagonalization process of special relativity time-space interval model metric tensor g in {t,ξ,θ,φ}, we find the spatial and temporal line characteristic quantities t1(t,ξ), τ1(τ,ξ),tt(t,τ,ξ) and ττ1(t,τ,ξ) corresponding to diagonal metric. Derived from these quantities, the dimension of time-space coordinate system is less than 4.
Bounded damped oscillatory solutions of Fisher equation
Authors: Li Xiang-Zheng  ,   College of Mathematics and Statistics, Henan University of Science and Technology, Luoyang 471003, China
Published: December 2020

To research the bounded damped oscillatory solutions of nonlinear evolution equation, we choose the Fisher equation as an example. The solutions with negative amplitudes of Fisher equation may become meaningful in the context of nonscalar models describing excitable media (e.g. the Belousov-Zhabotinsky (BZ) reaction). The theory of planar dynamical systems is used to study the existence conditions of bounded traveling wave solutions of Fisher equation. The bounded approximate damped oscillatory analytic solution is given by using LS method and linearization method. And its error is also estimated.
Controllability of complex networks based on propagation immunization
Authors: Lü Tian-Yang  , Piao Xiu-Feng  , Xie Wen-Yan  , Huang Shao-Bin  ,   College of Computer Science and Technology, Harbin Engineering University, Harbin 150001, China;,   College of Computer Science and Technology, Tsinghua University, Beijing 100084, China
Published: December 2020

Control of complex network reflects humans' comprehension of complex system and the ability to reform it. Up-to-date research establishes the controllability theory of the complex networks based on linear system control theory. The theory could find a minimal set of driver nodes which controls all nodes' state in a linear time invariant complex network with any topology. However, this theory does not take into account the immune node or failure node which blocks the control signal. While inheriting the advantages of the theory, in the paper we first refine the complex network control model based on propagation immunization. Second we adopt four methods which belong to random immunization strategy and targeted immunization strategy to determine the immune nodes, and analyze the controllability of 14 real networks. The experimental results show that when the nodes which have higher degrees, betweeness or closeness are treated as immune nodes, the control of complex networks will become more difficult.
Effect of weighted scheme on synchronizability based on different network structures
Authors: Wang Dan  , Jing Yuan-Wei  , Hao Bin-Bin  ,   Key Laboratory of Manufacturing Industrial Integrated Automation, Shenyang University, Shenyang 110044, Chinas;,   College of Information Science and Engineering, Northeastern University, Shenyang 110004, China
Published: December 2020

Motivated by the observations that the weight of a link in realistic networks is strongly correlated with the product of the corresponding degrees, we present an asymmetrical weighted scheme relating to the degrees of starting point and terminal point, and investigate the effects of weighted scheme on synchronizability in light of different network structures. The results show that the more heterogeneous the degree distribution of network, the more remarkable the effect on enhanced synchronizability by the weighted method is. However, there is little effect on enhanced synchronizability by the weighted method for the homogeneous random network. It is shown that no matter whether small world networks or scale-free networks, the synchronizability is maximal when the total strength of all in-links of every node is equal to one.
Complex spatiotemporal behaviors in a transmission line system terminated by an N-channel metal oxide semiconductor (NMOS) inverter
Authors: Zou Jian-Long  , Shen Yao  , Ma Xi-Kui  ,   State Key Laboratory of Electrical Insulation and Power Equipment, School of Electrical Engineering, Xi'an Jiaotong University, Xi'an m710049, China
Published: December 2020

Based on the traveling wave theory, a nonlinear discrete map of a transmission line system terminated by an N-channel metal oxide semiconductor (NMOS) inverter is established. After simulating by the nonlinear discrete map, it is found that the change of the reflection coefficient may lead to spatiotemporal bifurcation and chaos, and that the initial distribution significantly affects the spatiotemporal pattern of steady state. For the zero initial distribution, the spatiotemporal pattern is very regular, whereas the complex spatiotemporal pattern may appear when the initial distribution is nonzero. The analysis results demonstrate that the complex spatiotemporal behaviors originate from the infinite-dimensional essence of the transmission line and the nonlinear voltage-ampere characteristics of the NMOS inverter.
Complexity-based pattern recognition and diagnosis for engineering simulation system of HTR-PM
Authors: Fang Chao  , Sun Jun  , Lai Yu-Yang  ,   Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084, China;,   SOYOTEC Technologies Co., Ltd, Beijing 100081, China
Published: December 2020

Complexity-based pattern recognition and diagnosis for engineering simulation system of HTR-PM are carried through analyzing 12 state parameters of the nuclear reactor. It is shown that the complexities and robustnesses of HTR-PM simulation system are remarkably discrepant in three different operating modes (normal operation, increased ambient temperature and sudden leakage in primary loop). The effectivenesses of coupling calculations and feedback of multi systems of the HTR-PM simulator are also embodied in system robustness. All these results demonstrate that the method of complexity and robustness can indicate the availability of different parameters for recognizing and diagnosing the operating conditions of the HTR-PM.
Study on characteristics and fluid sensing of unparallel wall fiber micro-cavity Mach-Zehnder interferometer fabricated by femtosecond laser micromachining
Authors: Yin Li-Mei  , Zhang Wei-Gang  , Xue Xiao-Lin  , Bai Zhi-Yong  , Wei Shi-Lei  ,   Institute of Modern Optics of Nankai University, Nankai University, Tianjin 300071, China
Published: December 2020

It is found that two walls of fiber micro-cavity fabricated by femtosecond laser micromachining are not perpendicular to the fiber axis. Interference spectrum of the unparallel wall fiber micro-cavity Mach-Zehnder interferometer (MZI) shows abnormal characteristics, such as optical path difference decreasing linearly with wavelength increasing and the total loss decreasing with wavelength increasing. In this regard, we propose an unparalleled wall fiber micro-cavity MZI model and establish analytical theory. By using new models and theories, the new micro-cavity interferometer characteristics are studied, including that the effects of corner and depth on spectral peak wavelength are numerically analysed and transmission loss, absorption loss, insertion loss, infrared absorption loss of material as well as how they affect the interference fringe contrast are theoretically studied. Theoretical analyses and experimental results are in agreement with each other. For fluid sensing, a high-quality unparallel wall fiber micro-cavity MZI is fabricated. The interference fringe contrast of the fiber micro-cavity reaches up to 35 dB in water. Experimental results show that the sensor exhibits an ultrahigh RI sensitivities, as high as——12937.31 nm/RIU in aqueous solution of sucrose.
Observation of transitions in strontium triplet state and its application in optical clock
Authors: Gao Feng  , Wang Ye-Bing  , Tian Xiao  , Xu Peng  , Chang Hong  ,   Key Laboratory of Time and Frequency Primary Standards of Chinese Academy of Sciences, National Time Service Center of Chinese Academy of Sciences, Xi'an 710600, China;,   Graduate University of Chinese Academy of Sciences, Beijing 100049, China
Published: December 2020

In this paper we present a method of observing triplet state transitions of strontium. The intercombination transition is employed to pump the atom population from singlet-state (5s2)1S0 to triplet-state (5s5p)3P1 by a laser at 689 nm. Then 688 nm laser is also employed to divide atom population into the two other triplet-state states (5s5p)3P0 and (5s5p)3PP2. We can obtain the absorption signals of triplet-state transition (5s6s)3S1 → (5s5p)3P0 and (5s6p)3S1 → (5s5p)3P3P2. And these atomic absorption signals can be used for stabilizing the repumping light 679 nm and 707 nm directly to transition line of strontium. This method can be used in the Doppler cooling of strontium atoms.
Tunneling mode in symmetrical one-dimensional photonic crystal of single-negative material
Authors: Li Wen-Sheng  , Luo Shi-Jun  , Huang Hai-Ming  , Zhang Qin  , Fu Yan-Hua  ,   Department of Basic Science Hubei University of Automotive Technology, Shiyan 442002, China
Published: December 2020

Electrical single-negative material A and magnetic single-negative material B are used to constitute a symmetrical one-dimensional photonic crystal. Numerical calculation results indicate that a tunneling mode will appear in its band gap. With material layers increasing, the width of the tunneling mode narrows sharply, but its position remains unchanged. The position and width of the tunneling model are not sensitive to the incident angle. With the geometry thickness of the material reducing, the position of the tunneling mode is blue-shifted, but its width remains unchanged. With μA and εB increasing, the location of tunneling mode is red-shifted and the width decreases. Using the properties of the tunneling mode, it is possible to realise dynamic regulation for electromagnetic wave propagation.
Ionization currents and terahertz emission from the interaction of few-cycle laser pulses with gas targets
Authors: Du Hai-Wei  , Chen Min  , Zhang Kai-Yun  , Sheng Zheng-Ming  , Zhang Jie  ,   Key Laboratory for Laser Plasmas (Ministry of Education) and Department of Physics, Shanghai Jiaotong University, Shanghai 200240, China;,   Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
Published: December 2020

Based on a theoretical model and numerical simulations, the ionization currents and subsequent terahertz (THz) emission induced by the interaction of a few-cycle laser pulses with He gas targets are studied. It is shown that owing to the large transverse current generated by field ionization with few-cycle laser pulses, strong THz emission can be generated. The change of the carrier phase of the few-cycle laser pulses leads to the variation of the ionization currents. Correspondingly, the THz emission amplitude shows the characteristic as a periodic function of the carrier phase, which is also confirmed by one-dimensional particle-in-cell simulations. For a given carrier phase, the THz emission amplitude is not proportional to the laser amplitude. It shows at least two peaks at certain laser amplitudes. When the gas density profile is not uniform, the emission amplitude has a similar dependence on laser amplitude and carrier envelope phase, but the THz pulse duration and spectrum are quite different.
Spatially induced Airy-Bessel light bullets
Authors: Ren Zhi-Jun  , Wu Qiong  , Zhou Wei-Dong  , Wu Gen-Zhu  , Shi Yi-Le  ,   The Institute of Information Optics, Zhejiang Normal University, Jinhua 321004, China
Published: December 2020

Based on wave equation, we theoretically study the effect of spatially induced group velocity dispersion (SIGVD) of pulsed Bessel light beam propagation in free space. The results show that the third-order SIGVD can make pulsed Bessel beam gradually evolve into temporally Airy distribution. Airy-Bessel wave packet is such an exotic localized optical wave packet that it can possibly serve versatile tool in the research of light-matter interactions and has extensive applications. Hence we demonstrate the realization scheme of Airy-Bessel light bullets in free space by compensating the second-order SIGVD through utilizing dispersion management technique. To analyze the spatiotemporal propagation properties, we numerically simulate this light bullet propagation in a dispersion medium. The results show that it can retain spatial diffraction-free and temporal dispersion-free propagation in medium.
A scheme for improving optical signal-to-noise ratio of multi-carrier source based on recirculating frequency shifter
Authors: Liu Na  , Xi Li-Xia  , Li Jian-Ping  , Zhang Xiao-Guang  , Tian Feng  , Zhou Hao  ,   State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications, Beijing 100876, China
Published: December 2020

The output quality of frequency-locked multi-carrier source based on recirculating frequency shifter (RFS) technology is easily influenced by the inherent high-order harmonic crosstalk of modulator, especially the third-order crosstalk. In order to reduce the third-order crosstalk, a scheme that another RF signal whose frequency is 3fm is loaded on both ports of I/Q modulator is adopted. The first-order signal it produces is used to suppress the third-order crosstalk. A multi-carrier source whose number is 24 and maximal power difference is smaller than 0.1 dB is achieved through theoretical analysis and simulation research. The effective optical signal-to-noise ratio (OSNR) of multi-carrier source is improved by 2 dB compared with that before using the scheme of suppressing third-order crosstalk.