bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparative research on three types of coaxial double-corrugation periodic slow-wave structures
Authors: Ge Xing-Jun  , Zhong Hui-Huang  , Qian Bao-Liang  , Zhang Jun  ,   国防科学技术大学光电科学与工程学院，长沙  410073
Published: December 2020

The method for deducing expressions of arbitrary geometrical structures is studied in detail by using the Fourier series expansion. The dispersion curves of the slow-wave structures (SWSs) with the cosinoidal，rapezoidal and rectangular corrugations are obtained by numerical calculation. Moreover，the longitudinal resonance properties of the finite-length coaxial SWS are investigated with the S-parameter method. It is proposed that the introduction of a well designed coaxial extractor to slow-wave devices can help to reduce the period-number of the SWS，which not only can make the devices more compact，but also can avoid the destructive competition between various longitudinal modes. Furthermore，a compact L-band coaxial relativistic backward wave oscillator (RBWO) is investigated and optimized in detail with particle-in-cell (PIC) methods (KARAT code). In the preliminary experiments，the measured microwave frequency is 161 GHz，with a peak power level of above 102 GW，when the diode voltage is 670 kV and the current is 107 kA. The pulse duration (full-width at half-maximum) of the radiated microwave is 22 ns.
Temperature dependence of field emission of nano-diamond
Authors: Yang Yan-Ning  , Zhang Zhi-Yong  , Zhang Fu-Chun  , Zhang Wei-Hu  , Yan Jun-Feng  , Zhai Chun-Xue  ,   (1)西北大学光子学与光子技术研究所，光电子技术陕西省重点实验室，西安  710069; (2)西北大学光子学与光子技术研究所，光电子技术陕西省重点实验室，西安  710069；延安大学物理与电子信息学院，延安  716000; (3)延安大学物理与电子信息学院，延安  716000; (4)延安大学物理与电子信息学院，延安  716000；中国科学院西安光学精密机械研究所，西安  710068
Published: December 2020

The field emission characteristics of nano-diamond deposited on titanium substrate at various temperatures are studied. It was found that the emission current increases with increase of temperature and electric field，while the stability of the emission current basically does not change. The field emission characteristic deviates from classic Fowler-Nordheim theory. The mechanism of the emission current at different temperatures is analyzed. It may be due to the combined action of scale effect of the nano-diamond and masses of hot carrier produced by nano-diamonds in external electric field. In addition，the research indicates that larger current can be generated after titanium substrates being heated up to a certain degree in external electric field, which can have large effect on field emission，showing that the titanium substrate has a certain degree of temperature sensitivity and voltage sensitivity.
The global bifurcation and chaotic behaviours for the crystalline undulator radiation
Authors: Luo Shi-Yu  , Shao Ming-Zhu  , Luo Xiao-Hua  ,   (1)东莞理工学院电子工程学院，东莞  523106; (2)重庆大学电气工程学院，重庆  400044
Published: December 2020

Introducing sine-squared potential，the particle motion equation in the crystalline undulator field is reduced to the generalized pendulum equation with a dampping and a force terms in the classical mechanics frame in the dipole approximation. The properties of the phase plane are ananysed for a non-peturbated system by means of Jacobian elliptic function and the elliptic integral，and the solution of the equation and the period of the particle motion for this system are expressed exactly. The global bifurcation and a chaotic behaviour with the Smale horseshoe for the 3 kinds of orbits in a phase plane are analysed by Melnikov method. The critical condition of the system entering into a bifurcation or a chaoc is found. The result shows that critical condition is related to the parameters of the system，by suitably regulating the parameters of the system，the bifurcation or the chaos can be avoided or controlled in principle.
Elastic properties and refractive index of shocked Z-cut quartz
Authors: Li Xue-Mei  , Yu Yu-Ying  , Li Ying-Hua  , Zhang Lin  , Ma Yun  , Wang Xiao-Song  , Fu Qiu-Wei  ,   中国工程物理研究院流体物理研究所，冲击波物理与爆轰物理国防科技重点实验室，绵阳  621900
Published: December 2020

The elastic properties and optic characteristics of shocked Z-cut quartz were carefully examined，by using symmetric plate impact and in situ measurement. Results show that Z-cut quartz exhibits a simple-wave elastic response and keeps transparent up to a pressure of no less than 10 GPa，and it can be used as the opical window for velocity measurement within this pressure range. The relation of elastic shock wave velocity and particle velocity satisfies linear function very well. On the other hand，the velocity correction of Z-cut quartz at incident laser wavelength of 1550 nm can be better represented by exponential function than linear one，while the relation between refractive index and density of Z-cut quartz at 1550 nm satisfies the linear function very well. The results in this paper lay a foundation for using Z-cut quartz as optical windows of interferometer systems working with laser at 1550 nm wavelength.
Electronic structure and corrosion character of Mg alloys
Authors: Liu Gui-Li  ,   沈阳工业大学建筑工程学院，沈阳  110023
Published: December 2020

The electronic structure of Mg alloy was calculated with the recursion method. The result shows that the density of states of Mg in grain is similar to that on the surface of Mg alloy，but it is obviously different when O or O，H atoms exist on the surface of Mg alloys. This indicates Mg has similar properties whether in grain or on surface，but the properties of Mg change apparently after oxygen or hydrogen atom permeated in the surface layer of Mg alloy. Al，Y or La atom diffuses from grain to the surface and segregates there，because each the doped atom embedding energy of Al，Y or La atom on the surface is lower than that in grain. The affinity energy of Al-O，Y-O，La-O，Mg-O，Mg-O-H is negative，so they can form compound. Because the affinity energy of Mg-O-H is lower than that of Mg-O，Mg(OH)2 is more stable than MgO. In the early stage of oxidation，oxygen combined with Mg，Al，Y or La forming oxide. When Mg alloy is in corrosive medium，MgO reacts with H2O forming Mg(OH)2. Al2O3，（Y，La）2O3 and Mg(OH)2 can protect Mg alloys from corrosion and improve corrosion resistance.
Preparation and measurement of far-infrared electroluminescence emitter based on quantum confined acceptors
Authors: Liu Jing  , Zheng Wei-Min  , Song Ying-Xin  , Chu Ning-Ning  , Li Su-Mei  , Cong Wei-Yan  ,   山东大学威海分校空间科学与物理学院，威海  264209
Published: December 2020

GaAs/AlAs triple-quantum-well samples were grown by molecular beam epitaxy, and the middle GaAs quantum-well layer was delta-doped at the well centre with Be shallow acceptors. Then the far-infrared Teraherz prototype emitter was fabricated using the samples. Electroluminescence (EL) and current-voltage characteristics (I-V) were measured at 4.5 K. In the EL spectrum, a wide peak was observed clear 222 cm-1, which is attributed to the Be acceptor’s radiative transitions from the excited odd-parity states to the ground state. Nevertheless, the emission signal was weakened by non-radiative relaxation processes. In the I-V curve, the negative differential resistance characteristic at the position of 0.72 and 1.86 V was also observed clearly. This is attributed to the resonant tunneling between Be acceptor 1s3/2(Γ6+Γ7) energy level in the middle quantum-well and the HH1 band in the left-side non-doping quantum-well, as well as the resonant tunneling between the HH band in the right-side non-doping quantum-well and Be acceptor 2p5/2(Γ6+Γ7) energy level.
Fabrication and performance of organic light-emitting transistor based on vertical structure
Authors: Hu Zi-Yang  , Cheng Xiao-Man  , Wu Ren-Lei  , Wang Zhong-Qiang  , Hou Qing-Chuan  , Yin Shou-Gen  ,   (1)天津理工大学材料物理研究所，显示材料与光电器件教育部重点实验室，天津市光电显示材料与器件重点实验室，天津  300384; (2)天津理工大学材料物理研究所，显示材料与光电器件教育部重点实验室，天津市光电显示材料与器件重点实验室，天津  300384；天津理工大学理学院物理系，天津  300384
Published: December 2020

A vertical organic light-emitting transistor (VOLET) was fabricated by stacking a capacitor cell on top of an organic light emitting cell joined by a common source electrode，and the operation mechanism was analyzed. This unique device has the dual functions of emitting light as an OLED and switching current as a transistor. When the capacitor is under bias, the stored charges on the thin and coarse electrode shared by the two units modulate the charge injection of the OLED active unit, hence control the current flow and consequently tune the light emission. This device structure provides an extremely short channel in the nanometer range and a large conduction area (004 cm2), which supply enough output current (up to 02 mA) to drive the light emitting unit. As a result, thanks to the vertical integration, this device not only realizes multifunction but also operates at lower voltage, which provides a navel solution for the active-matrix OLED display application.
Absorption and surface enhanced Raman scattering spectra caused by combined Ag nanoparticles with Al2O3 dielectric layer
Authors: Huang Qian  , Zhang Xiao-Dan  , Ji Wei-Wei  , Wang Jing  , Ni Jian  , Li Lin-Na  , Sun Jian  , Geng Wei-Dong  , Geng Xin-Hua  , Xiong Shao-Zhen  , Zhao Ying  ,   (1)南开大学光电子薄膜器件与技术研究所，光电子薄膜器件与技术天津市重点实验室，光电信息技术科学教育部重点实验室，天津  300071; (2)南开大学化学学院化学系，天津  300071
Published: December 2020

Combined Ag nanoparticles with Al2O3 dielectric layer structure have been designed for molecular detection using surface enhanced Raman scattering. Optical absorption spectra studies reveal dipole plasmon resonance absorption property, which show regular red shift with the increasing of the thickness of Al2O3 layer. By use the combined structure as SERS substrates and rhodamine 6G as a test molecule, the results in this paper show that the scattering at 1064 nm increases with the thickness of Al2O3 dielectric layer which leads to the surrounding dielectric constant of Ag nanoparticles to increase.
Effect of δ barrier on persistent current in a quantum ring with multiple arms
Authors: Du Jian  , Wang Su-Xin  , Yuan Ai-Guo  ,   承德民族师范高等专科学校物理系,承德 067000
Published: December 2020

A new model of quantum ring with multiple arms containing δ barrier is proposed in this paper. The results imply that the persistent current shows behavior of nonperiodic oscillation with the size of the semiconductor ring increasing when the total magnetic flux is zero. The lower arm obtains minimal average persistent current because it contains the δ barrier. The persistent current generates periodic oscillation when the AB magnetic flux strengthens. It is related to not only the electrodes’ magnetic moment direction but also the tunneling electrons’ spin orientation. Furthermore, when the two magnetic moments are parallel, the Rashba spin-orbit interaction has the effect of changing the persistent current’s phase and phase difference. However, when the magnetic moments in the two electrodes are antiparallel, the Rashba spin-orbit interaction affects the amplitude of the persistent current. Our results also indicate that the difference of the persistent current in each arm is retated to the arm length and the magnetic flux’s distribution. The persistent currents which the two kind of wave functions correspond to are separated under definite conditions.
Crystallized poly-silicon thin film laterally induced by the Ni/Si oxide source
Authors: Liu Zhao-Jun  , Meng Zhi-Guo  , Zhao Sun-Yun  , Kwok Hoi Sing  , Wu Chun-Ya  , Xiong Shao-Zhen  ,   (1)南开大学信息学院光电子薄膜器件与技术研究所,天津  300071; (2)南开大学信息学院光电子薄膜器件与技术研究所,天津  300071；香港科技大学电子及计算机工程系,香港; (3)香港科技大学电子及计算机工程系,香港
Published: December 2020

With a Nickel-Silicon alloy as a target of magnetron-sputtering under Ar /O2 mixed gases, a new type of Ni/Si oxide source called self-released nickel source is fabricated. This kind of nickel source is different with the pure nickel source at both crystallized phenomenon and remainder of Ni. Low temperature poly-Silicon crystallized by self-released nickel source has lower nickel-residua and a controllable crystallization rate related without the thickness of Ni source. That is useful for widen process window. The relations of surface roughness and electrical characters of poly-Si crystallized by different source have been studied and discussed.
Cu deep level center in CdTe solar cell
Authors: Zheng Xu  , Li Bing  , Wang Zhao  , Zhang Dong-Ting  , Feng Liang-Huan  , Zhang Jing-Quan  , Cai Ya-Ping  , Zheng Jia-Gui  , Wu Li-Li  , Li Wei  , Lei Zhi  , Zeng Guang-Gen  ,   四川大学材料科学与工程学院，成都  610064
Published: December 2020

Cu would be doped and form deep level centers easily in CdTe solar cells. The deep level centers in ZnTe back contact and graphite back contact CdTe solar cells were studied by deep level transient spectroscopy(DLTS). The electronic density of states on zinc blende CdTe，VCd system and CdTe doping Cu were analyzed with density functional theory. The d-orbital splitting of Cu2+ in C3v and Td fields was obtained. The results show that two deep centers Ev+0206 eV and Ev+0122 eV，respectively，are attributed to substitutional Cu，energy of CdTe is reduced after Cu doping，and Cu could replace Cd.
Positron annihilation lifetime study of SmFeAsO superconductor
Authors: Hao Ying-Ping  , Chen Xiang-Lei  , Cheng Bin  , Kong Wei  , Xu Hong-Xia  , Du Huai-Jiang  , Ye Bang-Jiao  ,   中国科学技术大学近代物理系,合肥  230036
Published: December 2020

Positron annihilation lifetime spectroscopy (PALS) measurements of SmFeAsO polycrystalline sample were first carried out at 298 K. Two lifetime components of 1516 ps and 2903 ps were obtained. According to two-state capture model, the free annihilation lifetime in polycrystalline SmFeAsO is 1870 ps, which agrees well with the calculated value（in general gradient approximation） of 173 ps in SmFeAsO single crystal. Superposed-neutral-atom model and the finite-difference method (SNA-FD) were used to calculate the positron annihilation information in single-crystal SmFeAsO. The results show that the ratio of annihilation rate with valence electrons to annihilation rate with core electrons is 106, while the ratio of annihilation rate with electrons from Fe, As, Sm, and O atoms are 1∶13∶12∶1
A Ka-band folded double-ridged waveguide traveling-wave tube
Authors: He Jun  , Wei Yan-Yu  , Gong Yu-Bin  , Duan Zhao-Yun  , Wang Wen-Xiang  ,   电子科技大学物理电子学院 大功率微波电真空器件技术国防科技重点实验室，成都  610054
Published: December 2020

A novel slow-wave structure (SWS)， the folded double-ridged waveguide structure， is presented and its properties used for wide-band traveling-wave tube (TWT) are investigated. A Ka-band folded double-ridged waveguide TWT is modeled by Magic 3D and the beam-wave interaction is simulated and analyzed. Within the same beam condition， it is concluded from the comparison of folded double-ridged waveguide TWT and folded waveguide TWT that: in the condition of similar gain maximum， the folded double-ridged waveguide TWT has wider bandwidth of which is 22%， and higher electron efficiency of which is 9％.
Regression model of timbre attribute for underwater noise and its application to target recognition
Authors: Wang Na  , Chen Ke-An  ,   西北工业大学环境工程系,西安 710072
Published: December 2020

Timbre attribute is the most important feature to recognize a target. This paper presents a model of timbre features by multiple regression analysis applied in the recognition of underwater noise. At first, timbre attribute as a dependent variable is analyzed by the semantic differential evaluation and principal component analysis. And then an extended stepwise variables selection is proposed to select the optimal set as independent variables from auditory features that have been discussed in previous researches. Finally, the timbre features extracted by the regression model are used to recognize the underwater target. The results show that the extended regression analysis as a statistical method can find the relationship between timbre attribute and the auditory features. And the modeling timbre features calculated by several statistics of the sub-spectral features and the sub-temporal features are more effective than other features.
Variational assimilation combined with generalized variational optimization analysis for sea surface wind retrieval from microwave scatterometer data
Authors: Zhang Liang  , Huang Si-Xun  , Liu Yu-Di  , Zhong Jian  ,   解放军理工大学气象学院，南京 211101
Published: December 2020

multiple solution scheme, two dimensional variational assimilation, generalized variational optimization analysis, regularization method
Force chains in a uniaxially compressed static granular matter in 2D
Authors: Sun Qi-Cheng  , Jin Feng  , Wang Guang-Qian  , Zhang Guo-Hua  ,   (1)北京科技大学物理系，北京  100083; (2)清华大学水沙科学与水利水电工程国家重点实验室，北京  100084
Published: December 2020

Granular matter is a large assemblage of dense-packing particles. The interparticle forces are transmitted through heterogeneous chain architecture. The force chains would display different responses as external loading varies, and it would be directly related to the macroscopic mechanical properties of the granular system. Therefore, understanding the properties of force chains is fundamental to the study in granular systems. In this work, we firstly analyzed three characteristic time scales involved in processes occurring in granular systems, and proposed three dimensionless numbers to measure their relative importance. Secondly, a series of numerical simulations were conducted on a uniaxial compression system consisting of 12400 polydispersed particles. Our results showed that the shape of force distributions are unaffected by system preparation history and packing fractions in the range from 0855 to 0886, but mainly affected by the static surface friction. By defining three conditions for evaluating strong force chain, the probability distribution of force chain length was found in the form of power law with an exponent of 172, which is independent of packing fractions and static surface frictions in this static system.
Strong monochromatic harmonics generated by the interaction of two counter-propagating pulses with a foil target
Authors: Yan Chun-Yan  , Zhang Qiu-Ju  ,   山东师范大学物理与电子科学学院，济南  250014
Published: December 2020

This paper studies the strong harmonic generation in the interaction of two conter-propagating pulses with a foil target. When the thin target is irradiated by high-contrast circularly polarized laser pulse, the light pressure push high-density plasma forward.At the same time, because of the role of charge separation field, the ion beam and electron beam bunch well in longitudinal direction, and generate the plasma mirror with a forward movement at relativistic speed. When incidenting on a probe laser pulse on the plasma mirror in the opposite direction, they produce strong monochromatic N-order harmonics by Doppler shift, with the new duration of pulses compressed to 1/N of the original ones. This paper also discusses the effect of the laser and plasma parameters on plasma mirror movement which influences the order of harmonics, and also the effect of the stability of the relativistic plasma mirror on the harmonics.
Progress in the fabrication and application of photonic crystals
Authors: Ni Pei-Gen  ,   国家自然科学基金委员会数学物理科学部物理科学一处，北京  100085
Published: December 2020

It has been over 20 years since the concept of photonic crystal was proposed. Photonic crystal is now an important part of nano/micro-optics and quantum optics, and is also applied in many fields, such as information optics etc. The paper is focused on the progress in the fabrication of photonic crystals, especially the fabrication of two-dimensional and three-dimensional photonics. Meanwhile, the application of the photonic crystal is also reviewed. Then some perspectives are proposed.
Dispersion properties of two-dimensional dispersive and anisotropic-magnetized-plasma photonic crystals
Authors: Qi Li-Mei  , Yang Zi-Qiang  , Lan Feng  , Gao Xi  , Shi Zong-Jun  , Liang Zheng  ,   电子科技大学物理电子学院，成都  610054
Published: December 2020

Dispersion characteristics of two-dimensional dispersive and anisotropic-magnetized-plasma photonic crystals are studied using both the plane wave method and finite-difference time-domain method. When the wave vector lies in the periodic plane, due to the external magnetic field, two different regions of flat bands occur in the TE mode. Varying the values of external magnetic field will affect not only the location of flat bands, but also the position and size of band gaps. Increasing the background dielectric constant will make omnidirectional band gaps to be formed, and make the center of gaps reduced while making the width increase. When the wave vector lies in non-periodic plane, dispersion curves of magnetized plasma photonic crystal are no longer divided into TE and TM modes. With the increasing of the non-periodic wave vector, the location of gap shifts upward, and the gap width firstly increases and then varies little.
Precise periodic solutions and uniqueness of periodic solutions of some relative rotation nonlinear dynamic system
Authors: Wang Kun  , Guan Xin-Ping  , Qiao Jie-Min  ,   (1)燕山大学电气工程学院,秦皇岛 066004; (2)燕山大学理学院,秦皇岛 066004; (3)燕山大学理学院,秦皇岛 066004；燕山大学电气工程学院,秦皇岛 066004
Published: December 2020

The precise periodic solution and uniqueness of periodic solutions of some relative rotation nonlinear dynamical system possessing linear rigidity and nonlinear damping force and forcing periodic force is investigated. Firstly, the stability and uniqueness of limit cycles of a kind of autonomous nonlinear dynamical system are discussed. Secondly, the necessary condition of uniqueness of periodic solutions of the system is presented by using qualitative analysis method. The precise periodic solution of the system is obtained under certain conditions.
A complete third-order solution for classical monochromatic short-crested water waves
Authors: Huang Hu  , Xia Ying-Bo  ,   上海大学上海市应用数学和力学研究所，上海  200072
Published: December 2020

A new solution for classical monochromatic short-crested waves in finite water depth is presented by including the ambient uniform currents. With the aid of the original classical solution, we obtain a complete solution and show a variety of interaction mechanisms for the second-and third-order solution structures.
Analytic approximation for the soliton solution of the discrete modified KdV equation
Authors: Yang Pei  , Chen Yong  , Li Zhi-Bin  ,   (1)华东师范大学计算机科学技术系,上海 200241; (2)华东师范大学计算机科学技术系,上海 200241；华东师范大学上海市高可信计算重点实验室，上海 200062; (3)华东师范大学上海市高可信计算重点实验室，上海 200062
Published: December 2020

We extend the homotopy analysis method to solving the discrete modified KdV equation. The bright soliton solution expressed by a series of exponential functions is obtained, which agrees well with the exact solution. It indicates the validity and great potential of the homotopy analysis method in solving complicated nonlinear problems.
Convergence analysis of quantum-behaved particle swarm optimization algorithm and study on its control parameter
Authors: Fang Wei  , Sun Jun  , Xie Zhen-Ping  , Xu Wen-Bo  ,   江南大学信息工程学院,无锡  214122
Published: December 2020

Based on the analysis of particle swarm optimization algorithm, the particle is described in the quantum space and the potential energy field model is created. And then according to the swarms gregariousness, the quantum-behaved particle swarm optimization (QPSO) algorithm is derived. Within the framework of random algorithms global convergence theorem, the convergence of QPSO algorithm is discussed and is proved to be a kind of global convergence algorithm. Three kinds of control strategy are proposed for the unique parameter of QPSO algorithm and they are tested on five benchmark functions. According to the test results, some conclusions concerning the selection of the parameter are drawn.
Landau-Zener tunneling behaviors of Bose-Einstein condensates in a dichromatic optical lattice
Authors: Xi Yu-Dong  , Wang Deng-Long  , She Yan-Chao  , Wang Feng-Jiao  , Ding Jian-Wen  ,   湘潭大学物理系,纳米物理与稀土发光研究所,量子工程与微纳能源技术湖南省普通高等学校重点实验室，湘潭 411105
Published: December 2020

With considering Bose-Einstein condensates to be confined in a periodic dichromatic optical lattice, Bloch energy band structure and Landau-Zener tunneling behaviors of the first and second band gaps are studied in this paper. It is shown that when the relative phase between the two lattices increases from 0 to π, the width of the first band gap in the Bloch energy band increases, while the width of the second band gap decreases. Meanwhile, it is found that the depth and the relative phase between the two lattices have both an important effect on Landau-Zener tunneling properties.
The mean first-passage time for a cancer development system driven by colored cross-correlated noises
Authors: Yang Jian-Hua  , Liu Xian-Bin  ,   南京航空航天大学振动工程研究所,南京  210016
Published: December 2020

In this paper, the mean first-passage times for a cancer development system driven by colored cross-correlated noises are investigated. Based on the Novikov theorem and the Fox approach, the approximate Fokker-Planck equation and the explicit expressions of the mean first-passage time are derived. Numerical results show that: if the coupling strength between the two noises is negative, the mean first-passage time is a decreasing function of the two noise intensities, but an increasing function of the correlation time; if the coupling strength between the two noises is positive, then the value of the monotonic mean first-passage time versus the additive noise intensity depends on the transition direction. And in addition, the mean first-passage time is a non-monotonic function of the multiplicative noise intensity, but a decreasing function of the correlation time.
Function projective synchronization of quntum cellular neural network and Lorenz hyperchaotic system with uncertain parameters
Authors: Yang Xiao-Kuo  , Cai Li  , Zhao Xiao-Hui  , Feng Chao-Wen  ,   空军工程大学理学院，西安 710051
Published: December 2020

In the paper, function projective synchronization of quantum cellular neural network with uncertain system parameters and Lorenz hyperchaotic system is studied. The adaptive controllers are proposed to make the states of two different chaotic systems asymptotically synchronized up to a desired scaling function. We also present the relevant proof by applying Lyapunov stability theory. Moreover, linear independence of coefficient vector of uncertain system parameters in quantum cellular neural network is analyzed theoretically, which aims to realize the unknown parameter identification and estimation. Numerical simulations are made to show the effectiveness of the function projective synchronization and parameter estimation.
Dynamic behavior of negative differential conductivity and chaotic phenomena in Si thyristor
Authors: Tan Ping-An  , Zhang Bo  , Qiu Dong-Yuan  ,   (1)华南理工大学电力学院，广州 510640; (2)华南理工大学电力学院，广州 510640；湘潭大学信息工程学院，湘潭 411105
Published: December 2020

Stability and dynamic behavior of negative differential conductivity in thyristors are studied in this paper, which aims to clarify the mechanism of chaotic phenomena in the thyristor. Firstly, a spatio-temporal model of the thyristor is established, and the boundary condition of the system is obtained based on the linear stability analysis. The results show that the instability of thyristor is not only determined by the characteristics of negative differential conductivity, but also depends on the external conditions. Computer simulation is made to verify the proposed view for different external control parameters. The theoretical results are also confirmed by experimental measurements. So, the mechanism of chaotic phenomena in thyristor is clearly explained.
Mechanism of measure synchronization in coupled Hamiltonian systems
Authors: Tian Jing  , Qiu Hai-Bo  , Chen Yong  ,   (1)兰州大学理论物理研究所,兰州 730000; (2)兰州大学理论物理研究所,兰州 730000；北京科技大学物理系,北京 100083
Published: December 2020

Measure synchronization is an interesting phenomenon found in coupled Hamiltonian systems. By taking Poincaré section analysis, it is found that the separatrix crossing behaviors is the dynamical mechanism behind measure synchronization transition in both time-discrete and time-continuous coupled Hamiltonian systems.
Dynamical modeling and analysis of current mode controlled switching converter with ramp compensation
Authors: Bao Bo-Cheng  , Zhou Guo-Hua  , Xu Jian-Ping  , Liu Zhong  ,   (1)南京理工大学电子工程系，南京 210094; (2)南京理工大学电子工程系，南京 210094；江苏技术师范学院电气信息工程学院，常州 213001; (3)西南交通大学电气工程学院，成都 610031
Published: December 2020

Buck, boost and buck-boost converters are three basic switching DC-DC converters. Current mode controlled switching DC-DC converters have two boundaries in a wide circuit parameters variation range. Based on the ramp up and ramp down slopes of the inductor current before and after the turn on of power switch for switching DC-DC converters, a unified model of the current mode controlled switching DC-DC converters with ramp compensation is established in this paper. Only three parameters appear in this model after dimensionless normalization, from which the dynamical behaviors of switching DC-DC converters in continuous conduction mode (CCM) and discontinuous conduction mode (DCM) can be effectively illustrated. By utilizing the proposed unified model, two orbit state shifting borderline equations are derived, from which three operation state regions namely the stable period-one region, CCM robust chaos region, and DCM weak chaos and strong intermittence region, of switching DC-DC converters can be determined. The two-dimensional parameter bifurcation diagrams of switching DC-DC converters and circuit experimental observations of current mode controlled buck converter verify the analysis results of the partitioning of operation state regions by two borderline equations.
A global routing method for weighted scale-free networks
Authors: Pu Cun-Lai  , Pei Wen-Jiang  ,   东南大学信息科学与工程学院，南京 210096
Published: December 2020

In this article, a global routing method is proposed for weighted scale-free networks. To bypass the central nodes and alleviate the congestion, it chooses the best route according to the minimum value of the cost function which is based on the node strength. Simulation results show that the network capacity is improved more than 10 times by our method than by the shortest path strategy at the cost of a slightly growth in the average path-length.
Optimized structure and thermodynamic properties of atomic clusters in the framework of the extended Hubbard model
Authors: Zheng Xiao-Jun  , Zhang Jun  , Huang Zhong-Bing  ,   湖北大学物理学与电子技术学院,武汉 430062
Published: December 2020

By using a numerical exact diagonalization method, the properties of atomic clusters with atom number N=5 and N=6 are investigated in the framework of the extended Hubbard model. The optimized structure and the corresponding total spin S are obtained both as a function of Hubbard onsite interaction U, nearest-neighbor Coulomb repulsion V and filling number of electrons. Results show that with V increasing, the optimized structure of cluster turns into a chain or star-like structure with fewer bonds. The thermodynamic properties are also analyzed based on the distribution of energy levels of cluster with an optimized structure.
Ocean duct inversion from radar clutter using variation adjoint and regularization method (Ⅱ): inversion experiment
Authors: Sheng Zheng  , Huang Si-Xun  ,   解放军理工大学气象学院，南京  211101
Published: December 2020

On the theoretical basis, using simulated and measured radar clutter data, we tested the inversion algorithm respectively. In simulated radar clutter data inversion, inversion results with and without considering the regularization item are discussed. In real radar clutter data inversion, dependence of the inversion results on the precision of the first guess values is discussed, in which the first guess values are either emperical model values or statistics inversion results, respectively. Finally, the advantages and disadvantages are compared between the variation adjoint regularization algorithm and the traditional statistical inversion algorithm, pointing out the direction of improvement in future work.
Laser induced damage and fracture of optical fiber in vacuum chamber
Authors: Zhao Xing-Hai  , Hu Jian-Ping  , Gao Yang  , Pan Feng  , Ma Ping  ,   (1)成都精密光学工程研究中心，成都  610041; (2)中国工程物理研究院电子工程研究所，绵阳  621900
Published: December 2020

The characteristics of Q-switched Nd:YAG laser induced damage to fused optical fibers has been investigated experimentally. A scheme of laser induced damage to optical fiber in a vacuum chamber was presented and carried out.With this scheme, the air pressures on the input face of optical fiber was reduced to 10—100 Pa, laser-induced breakdown on the optical fiber end face was significantly suppressed, the breakdown threshold increased to 185 times that in the atmosphere. The damage morphology of optical fiber end face was analyzed, which was the result of the combined actions of laser pulses standing wave and ablation. The existence of a large number of defects on or under the fiber end face reduces the anti-laser-induced damage ability of the optical fibers. Under the vacuum condition, another damage mode——the fiber “entry” segment damage occurred. This “entry”　segment damage mode occurred at 5—30 mm distances from the input end face of optical fiber, the blasting damage area was 1—3 mm long along the fiber core axis. That the initial reflection of laser beam at the interface of fiber cladding and core causes laser focusing which induced the entry damage, was proved by theory and simulations.
Research on modulation property of photonic crystals in terahertz range
Authors: Zhang Rong  , Cao Jun-Cheng  ,   中国科学院上海微系统与信息技术研究所，信息功能材料国家重点实验室，上海  200050
Published: December 2020

In this work, the terahertz transimission spectrum through a one-demensional (1D) photonic crystal made from doped semiconductor n-GaAs/polycarbonate is studied by the transfer-matrix method. We show that, compared with most photonic crystals made from two different dielectrics, the doped semiconductor/dielectrics 1D photonic crystals can not only form the photonic gap, but also enhance the terahertz transmission through n-GaAs. We also propose and research a terahertz modulator based on the 1D photonic crystals, the transimitted terahertz waves through which can be modulated by different carrier densities in the semicondutor by varying the applied voltage.
Acoustic band gaps in finite-sized two-dimensional solid/fluid phononic crystals
Authors: Gao Guo-Qin  , Ma Shou-Lin  , Jin Feng  , Kim Tong-Beum  , Lu Tian-Jian  ,   (1)西安交通大学机械学院，西安 710049; (2)西安交通大学强度与振动教育部重点实验室，西安  710049
Published: December 2020

Acoustic band gaps in two-dimensional phononic crystal consisting of a finite-sized square array of parallel hollow aluminum cylinders in air are investigated with the finite difference time domain (FDTD) method. Experimental measurements were carried out to validate the theoretical predictions with excellent overall agreement achieved. The numerical method is used subsequently to study the band gap properties of phononic crystals composed of cylinder (both solid and hollow)/fluid systems for two different acoustic impedance ratios. For both types of system, the influence of the transverse size of the phononic crystal on the propagation properties is analyzed, and the minimum size to achieve the largest band gap width for different filling factors is determined.
Experimental generation of Laguerre-Gaussian beam using angular diffraction of binary phase plate
Authors: Ren Yu-Xuan  , Wu Jian-Guang  , Zhou Xiao-Wei  , Fu Shao-Jun  , Sun Qing  , Wang Zi-Qiang  , Li Yin-Mei  ,   (1)中国科学技术大学国家同步辐射实验室，合肥 230029; (2)中国科学技术大学合肥微尺度物质科学国家实验室，合肥 230026；中国科学技术大学物理系，合肥 230026; (3)中国科学技术大学合肥微尺度物质科学国家实验室，合肥 230026；中国科学技术大学物理系，合肥 230026；中国科学技术大学安徽省光电子科学与技术重点实验室，合肥 230026; (4)中国科学技术大学物理系，合肥 230026
Published: December 2020

A phase plate was fabricated on a quartz crystal using ion beam etching technique with a predesigned angular phase mask, which can modulate the phase of light illuminating the phase plate by 0 and π rad. Analyzed the field distribution of the diffracted light by angular diffraction theory, which shows the resulting beam is a superposition of two Laguerre-Gaussian(LG) beams with opposite topological charges. Illuminating the phase plate using the expanded beam with diameter 4 mm generates the superposition of two LG beams with the same radian index p=0 and opposite angular index l=20 and l=-20 By increasing the aperture of the illuminating beam, LG beam with higher p index can be acquired, while the l index remains opposite.
Experimental study on all-normal-dispersion mode-locked fiber laser with optimal spectral filtering position
Authors: Ouyang Chun-Mei  , Chai Lu  , Zhao Hui  , Hu Ming-Lie  , Song You-Jian  , Wang Qing-Yue  ,   天津大学精密仪器与光电子工程学院，光电信息技术科学教育部重点实验室，天津 300072
Published: December 2020

Employing nonlinear polarization rotation, an all-normal-dispersion mode-locked fiber ring laser was constructed, in which a fiber filter with 10 nm bandwidth was used in the cavity to provide the additional self-amplitude modulation. The important role of the filter position plays in the high-chirped pulse shaping in the laser has been experimentally demonstrated by choosing different locations of the filter in the cavity. A mode-locked pulse series, with the averaged power of 922 mW, output pulse duration of 62 ps, and pulse repetition frequency of 266 MHz, corresponding to the pulse energy of 35 nJ, was obtained in the optimized filter position under a pump power of 320 mW. By the numerical simulation, the propagation dynamics of pulses in the three cases of spectral filter (SF) position in the cavity are obtained and analyzed. The optimal location of the SF is found, which is in agreement with our experimental result.
Effective radius of curvature of partially coherent flat-topped beam propagating through atmospheric turbulence
Authors: Ji Xiao-Ling  ,   四川师范大学物理系，成都 610066
Published: December 2020

The analytical expression for the effective radius of curvature R of a partially coherent flat-topped beam propagating through atmospheric turbulence is derived. It is shown that R decreases due to turbulence. However, position zmin where R reaches its minimum will change due to the turbulence when the strength of turbulence is strong enough. The effective radius of curvature R increases with the increase of beam coherence parameter β when the strength of turbulence is weak, while R decreases with β increasing when the strength of turbulence is strong. The R decreases slowly with the increase of beam order M(N). The R of partially coherent flat-topped beam with larger β and smaller M(N) is more sensitive to turbulence. In addition, in free space the wavefront of partially coherent flat-topped beam can be regarded as a spherical surface in the far-field, which is independent of the beam parameters. However, in turbulence the effective radius of curvature depends on the beam parameters in the near field and also in the far field.
Radiation force of highly focused cosine-Gaussian beam on a particle in the Rayleigh scattering regime
Authors: Jiang Yun-Feng  , Lu Xuan-Hui  , Zhao Cheng-Liang  ,   (1)浙江大学物理系，杭州  310027; (2)浙江大学物理系，杭州  310027；华东师范大学精密光谱科学与技术国家重点实验室，上海  200062
Published: December 2020

The radiation force of highly focused cosine-Gaussian beam acting on a particle in the Rayleigh scattering regime is theoretically investigated in this paper. The results show that it is feasible to utilize cosine-Gaussian beam in optical trapping system. Unlike the conventional optical beams, the cosine-Gaussian beam could simultaneously trap particles whose refractive index is lower or higher than the ambient.
Vibration of two equal-radius protein bubbles in Bingham fluid
Authors: Wang Hai-Min  , Ma Jian-Min  , Zhang Wen  ,   (1)复旦大学力学与工程科学系，上海  200433; (2)上海理工大学动力工程学院，上海  200093
Published: December 2020

Based on the finite deformation equation of protein bubble with viscoelastic film, and taking into account the Bjerknes effect that one oscillating bubble acts on the ather in Bingham liquid, a nonlinear equation describing the vibration of two equal-radius protein bubbles in Bingham fluid is built. The numerical simulation is used to solve the above nonlinear equation. The results show that, increasing the plastic viscosity of Bingham liquid the protein bubble wall will vibrate with higher decrement velocity of amplitude, and with lower frequency; shortening the distance between bubbles, the bubble wall will vibrate with a higher frequency and a higher decrement velocity of amplitude. Furthermore, the smaller the bubble size is, the higher the increment of frequency and decrement velocity of amplitude are. The two bubbles in Bingham fluid will vibrate with higher frequency and higher decrement velocity of amplitude than that of a single bubble.
Planar focus effect of visible light metamaterials
Authors: Xiang Jian-Kai  , Ma Zhong-Hong  , Zhao Yan  , Zhao Xiao-Peng  ,   西北工业大学应用物理系，西安  710129
Published: December 2020

In this paper are described three composite structures of visible light metamaterials, i.e. dendritic structures and dendritic structures, dendritic structures and silver film, dendritic structures and indium tin oxide slice, based on the physical model of “double-fishnet” structure. By double template-assisted electrochemical deposition, silver dendritic structure arrays and silver films are fabricated, which is useful for achieving the above three composite structures. It is revealed that all of the three composite structures have the same effects according to the transmission spectra and reverberation spectra.A comparison among all of the three composite structures clealy shows that the composite structure of dendritic structures and indium tin oxide slice has the best performance, such as low loss and distinct planar focus effect. Through adjusting the experiment conditions, three kinds of visible light metamaterials are prepared which can realize planar focus effects at red, green and blue light frequencies, separately.
Extraordinary transmission through one-dimensional metallic gratings with sub-wavelength slits under transverse electric wave excitation
Authors: Wang Ya-Wei  , Liu Ming-Li  , Liu Ren-Jie  , Lei Hai-Na  , Deng Xiao-Bin  ,   (1)江苏大学机械工程学院,镇江  212013; (2)江苏大学理学院,镇江  212013
Published: December 2020

To show how to achieve the extraordinary transmission of one-dimensional metallic gratings with sub-wavelenghth slits, the transmission distribution of transverse electric (TE) wave through one-dimensional metallic gratings with sub-wavelenghth slits with a dielectric substance applied on it in different ways has been simulated by the finite-difference time-domain method. The relations between the refractive index of dielectric and the transmission efficiency is elicited from simulation, which show that the extraordinary transmission can be produced at several special wavelengths. Then, a new theory named the guided-mode-like resonance theory is put forward based on the guided-mode resonance theory, which is well suited for the extraordinary transmission under the TE-polarized wave excitation, and it is concluded that the guided-mode-like resonance is the main reason for the extraordinary transmission of TE-polarized wave. Thus, the new theory can explain the problems which cant be explained by the traditional theory. In a word, the guided-mode like resonance theory reveals the physical nature of the extraordinary transmission phenomenon which provides a theoretical basis for the further study of the extraordinary transmission phenomenon.
Analysis of acceleration response of metal rubber isolator under random vibration
Authors: Yan Hui  , Jiang Hong-Yuan  , Liu Wen-Jian  , Hao Zhen-Dong  , Ulannov A. M.  ,   (1)哈尔滨工业大学机电工程学院，哈尔滨 150001; (2)萨玛拉国立航空航天大学，俄罗斯萨玛拉 443086
Published: December 2020

Based on the theoretical study of the dry friction isolation system under the random vibration, a formula for the description of the acceleration response of metal rubber (MR) isolation system under random vibration was derived. An experimental research for the MR isolator subject to random vibration excitation was carried out, and the effects of the relative density, the preliminary deformation, and the acceleration level of excitation on the root mean square of acceleration response for the isolation system were analyzed and depicted in curves. The theoretical root mean square of acceleration response was compared with the experimental ones, and the range for the practical use was determined.
Optimization of diagnostic system for neutron penumbral imaging in inertial confinement fusion
Authors: Yu Bo  , Ying Yang-Jun  , Xu Hai-Bo  ,   (1)北京应用物理与计算数学研究所，北京  100088; (2)中国工程物理研究院研究生部，北京  100088
Published: December 2020

Penumbral imaging of the neutron production in laser-driven inertial confinement fusion experiment is an important diagnostic technique. In order to meet the resolution requirement, we simulate the point spread function (PSF) under the conditions of different source-aperture distances, different thicknesses, different outer radii, and different shapes of the aperture. Base on the sharpness and the isoplanaticity of PSF, the diagnostic system can be optimized. According to the simulation results, tolerant misalignment of system is analysed: a resolution of 15 μm can be satisfied by the linear reconstruction method, and a resolution of 5 μm can be achieved by using the nonlinear reconstruction method.
Characteristics of the plasma discharge generated in dielectric capillary at atmospheric pressure
Authors: Huang Wen-Tong  , Li Shou-Zhe  , Wang De-Zhen  , Ma Teng-Cai  ,   大连理工大学物理与光电工程学院，大连 116024
Published: December 2020

An atmospheric-pressure argon plasma discharge with a length of 63 cm is generated in a quartz capillary by using a pair of hollow needle electrodes. The discharge mode transition from abnormal glow to arc is investigated by means of electrical measurement and optical emission spectroscopy. The effects of the distance between two needle electrodes and the operating frequency of power supply on the voltage-current characteristics are discussed. The plasma electron density was estimated to be the order of 1014 cm-3 in the arc discharge. Moreover, the variation of gas temperature with the applied voltage is also studied, which is closely associated with the power dissipation. Furthermore, in measuring the oxygen atoms generated in argon/oxygen arc plasma discharge by optical actinometry, we found that the amount of oxygen atoms almost does not change with the rise of oxygen concentration.
Study on nanohardness of helium-implanted 4H-SiC
Authors: Zhang Yong  , Zhang Chong-Hong  , Zhou Li-Hong  , Li Bing-Sheng  , Yang Yi-Tao  ,   (1)中国科学院近代物理研究所，兰州  730000; (2)中国科学院近代物理研究所，兰州  730000；中国科学院研究生院，北京  100049
Published: December 2020

The hardness of 4H-SiC, which was high-temperature (500 K) helium-implanted to fluences of 3×1016 ions cm-2 and subsequently thermally annealed at the temperature ranging from 773 to 1273 K, was studied by nanoindentation. It is found that the hardness of the implanted 4H-SiC increases at the first, then decreases, and then increases again with increasing annealing tempeature in the temperature range of 500—1273 K, and significant increase in hardness is observed at 773 K. The behavior is ascribed to the changes of the density, length, and tangling of the covalent Si—C bond through the recombination of point defects, clustering of He-vacancy, and growth of helium bubbles during the thermal annealing.
Experimental analysis of charge transfer efficiency degradation of charge coupled devices induced by proton irradiation
Authors: Wang Zu-Jun  , Tang Ben-Qi  , Xiao Zhi-Gang  , Liu Min-Bo  , Huang Shao-Yan  , Zhang Yong  ,   (1)清华大学工程物理系，粒子技术与辐射成像教育部重点实验室,北京  100084；西北核技术研究所，西安  710024; (2)西北核技术研究所，西安  710024
Published: December 2020

The experiments on charge coupled devices (CCD) irradiated by protons were carried out. The charge transfer efficiency (CTE) of CCD was measured before and after proton radiation. The radiation damage mechanism of CTE degradation was analyzed. The CTE degradation induced by irradiation of protons of different energies was compared. The experimental results were explained by the theoretical analysis based on the calculation by radiation particle transport simulation software.