bluuebunny/crossref_metadata_2025 huggingface dataset:
A novel microstructure for in-situ measurement of residual stress in micromechanical thin films
Authors: Yu Yi-Ting  , Yuan Wei-Zheng  , Qiao Da-Yong  , Liang Qing  ,   西北工业大学微/纳米系统实验室,西安 710072
Published: December 2020

A novel microstructure for in-situ measuring residual stress in micromechanical thin films by the method of critical buckling observation was proposed and two different samples were fabricated using surface micromachining technique. The experimental apparatus was built for in-situ observation of critical buckling patterns of these microstructures during sacrificial layer etching. Then, the states of residual stresses can be distinguished directly by the buckling patterns and the magnitudes can be estimated with finite element method (FEM) when the values of critical etching length have been measured. Before the measurement, effects of various parameters on the critical buckling stress were investigated in detail with FEM in advance. After that, measurements of residual stresses using the new microstructures were carried out and the results were in good agreement with that obtained from micro rotating structures. It is consequently revealed that measurement of residual stresses by this new microstructure has evident advantages over the conventional buckling observation methods. Both compressive and tensile residual stresses in wide ranges of amplitude can be measured, just using a single appropriately designed microstructure. Therefore, the usefulness of layout space can be greatly improved.
The structure and potential energy function of LiO2(C2V，X2A2) molecule
Authors: Yang Ze-Jin  , Gao Qing-He  , Guo Yun-Dong  , Cheng Xin-Lu  , Zhu Zheng-He  , Yang Xiang-Dong  ,   (1)辽宁中医药大学信息工程学院物理教研室,沈阳 110032; (2)内江师范学院物理系,四川内江 641112; (3)四川大学原子与分子物理研究所,成都 610065
Published: December 2020

By using QCISD(T)/aug-cc-pvtz method, the equilibrium geometry of LiO2 molecule has been calculated. The possible electronic state and the reasonable dissociation limit of the ground state of LiO2 molecule is determined based on atomic and molecular reaction statics. The analytic potential energy function of LiO2(C2V，X2A2) molecule was derived by many-body expansion theory.
The molecule production rate in a Λ configuration atom-molecular three-level system
Authors: Sun Xiao-Peng  , Feng Zhi-Fang  , Li Wei-Dong  , Jia Suo-Tang  ,   (1)山西大学物理电子工程学院,理论物理研究所,太原 030006; (2)山西大学物理电子工程学院,理论物理研究所,太原 030006；山西大学物理电子工程学院,量子光学与光量子器件国家重点实验室,太原 030006; (3)山西大学物理电子工程学院,量子光学与光量子器件国家重点实验室,太原 030006
Published: December 2020

In this paper, we investigate the quantum dynamics of the Λ　configuration atom-molecular three-level system analytically and numerically. Then the production rate of molecule is consequently studied. Our results show that the production rate depends on the initial condition. Under ideal condition, one can have complete transformation with the equivalent Rabi frequency when the initial state is the atomic state, while for the dark state, the production rate is constant. The detuning of the coupling optical field usually decreases the production rate, but increases it for the dark state.
A research of conformal optical system based on Wassermann-Wolf equations
Authors: Li Dong-Xi  , Lu Zhen-Wu  , Sun Qiang  , Liu Hua  , Zhang Yun-Cui  ,   (1)长春光学精密机械与物理研究所,应用光学国家重点实验室,长春 130033; (2)长春光学精密机械与物理研究所,应用光学国家重点实验室,长春 130033；中国科学院研究生院,北京 100039
Published: December 2020

A method for polynomial fitting of Wassermann-Wolf surfaces and the results are presented. Conformal optics by which the missile dome is shaped to aerodynamic requirements generally introduces various kinds of aberrations as targe as tens to hundreds of wave lengths across the field of regard. Through polynomial fitting of Wassermann-Wolf surfaces and using Zernike polynomials instead of traditional merit function, the conformal optical system is implemented and an example is demonstrated. The results show that MTF of the optical system approaches to the diffraction limit across the field of view.
Diffraction effect of the seams between the segmented gratings in a single-pass tiled-grating compressor
Authors: Zuo Yan-Lei  , Wei Xiao-Feng  , Zhu Qi-Hua  , Wang Xiao  , Liu Hong-Jie  , Huang Zheng  , Guo Yi  , Ying Chun-Tong  ,   (1)清华大学工程物理系，北京 100084; (2)中国工程物理研究院激光聚变研究中心，绵阳 621900; (3)中国工程物理研究院激光聚变研究中心，绵阳 621900；清华大学工程物理系，北京 100084
Published: December 2020

By using Fourier optics, a model based on the far field about the Gauss pulse is set up，by which the effect of seams on the far field can be studied. Numerical simulation shows that pulse-width narrowing will appear in the case of single seam and the Fourier-translation-limited pulse-width of the input pulse will determine whether the pulse width in the far field becomes narrow or broad. In addition, the irradiance in the focus decreases and two sub-peaks appear beside the central peak, and their intensties increase with the widening of seams.
A single-photon detector in the near-infrared range
Authors: Sun Zhi-Bin  , Ma Hai-Qiang  , Lei Ming  , Yang Han-Dong  , Wu Ling-An  , Zhai Guang-Jie  , Feng Ji  ,   中国科学院物理研究所，北京 100080
Published: December 2020

A single photon detector operating in the Geiger mode is cooled to a moderate temperature by using Peltier cooling, and a gate pulse is coupled to the avalanche diode through capacitance. It uses a moderate delay and sampling gate modulation to prevent the positive and the negative transient pulses from influencing the detection of true photon avalanches, a dead time modulation feedback control circuit to suppress the afterpulsing, and an optimized circuit to reduce the dark counts. The performance test shows that at the optimum operation point the quantum efficiency is about 18%, the dark count rate is less than 4×10-6 ns-1 and the noise-equivalent power is 2.4×10-19 W/Hz1/2.
Deterministic quantum key distribution based on random phase coding
Authors: Lin Qing-Qun  , Wang Fa-Qiang  , Mi Jing-Long  , Liang Rui-Sheng  , Liu Song-Hao  ,   华南师范大学信息光电子科技学院光子信息技术实验室，广州 510631
Published: December 2020

We propose a new quantum key distribution scheme based on random phase coding. In this scheme, the sender and the receiver can share the secret information without basis reconciliation,and besides, this scheme is more efficient. As the phase of the qubit is coded randomly, this protocol is robust even when the source is not a prefect single photon. We show theoretically that it has higher security against the attacks, such as the photon-number-splitting, the impersonation attack, and the Trojan attack, etc., than the previous QKD scheme.
Stability of LD pumped passively Q-switched solid-state lasers
Authors: Zhang Qiu-Lin  , Su Hong-Xin  , Sun Jiang  , Guo Qing-Lin  , Fu Guang-Sheng  ,   河北大学物理科学与技术学院，保定 071002
Published: December 2020

For the laser diode pumped Cr,Nd∶YAG passively Q-switched Nd:YVO4 laser, in order to improve the stability of the Q-switched pulses, a long cavity is adopted, and the gain medium is located at the middle of the cavity. In the experiments, stable pulses are obtained. At the maximum incident pump power of 17.5W, the repetition rate increases to 71.3 kHz and the pulse width (FWHM) is narrowed to 0.4μs. The pulse-to-pulse amplitude fluctuation is less than ±10%. The inter-pulse timing jitter of the Q-switched pulse train is found to be less than ±3.5%.
Study of nonlinear hot image effect of Gaussian optical beams
Authors: Wang You-Wen  , Hu Yong-Hua  , Wen Shuang-Chun  , You Kai-Ming  , Fu Xi-Quan  ,   (1)湖南大学计算机与通信学院,长沙 410082; (2)湖南大学计算机与通信学院,长沙 410082；衡阳师范学院物理与电子信息科学系,衡阳 421008
Published: December 2020

In high-power lasers, nonlinear hot image is likely to damage expensive optics. The location and intensity of hot image of plane light wave has widely been studied. However, in the operating lasers, the light beam possesses a limited spatial width. Based on the aberrationless model of self-focusing, the location and intensity of hot image of Guassian optical beams is investigated. It is shown that the location and intensity of hot image greatly differ from those of plane light wave when the Guassian beam has a small beam waist, while they approximately equal those of plane light wave for a very big beam waist.
Solitary evolution and deflection of matching Gauss beam in dissipative crystals
Authors: Liu Shi-Xiong  , Liu Jin-Song  , Wang Cheng  , Zheng Zi-Wei  , Zhang Guang-Yong  , Zhang Hui-Lan  ,   武汉光电国家实验室光电子科学与工程学院，华中科技大学，武汉 430074
Published: December 2020

The solitary evolution and deflection of matching Gauss beam have been investigated in biased dissipative photovoltaic-photorefractive crystals. For a given dissipative system that supports a determinate dissipative screening-photovoltaic soliton (DHSP), one call find a corresponding Gauss beam which matches with the system parameters, which will evolve into a steady-state spatial soliton and propagate steadily in the given dissipative crystal. At the same time, we have investigated the impact of diffusion on the propagation (or solitary evolution) of the matching Gauss beam in the dissipative system. It is indicated that the diffusion effect can cause deflection of the matching Gauss beam during the transmission, and the deflection process is extremely similar to that of the corresponding DHSP soiliton. By comparing the two deflection results, we found that for the matching Gauss beam, the numerical result of deflection is close to the analytical result of the bright DHSP soliton. In a word, the solitary evolution and propagation (including the deflection) of the matching Gauss beam is quite close to those of the DHSP in the dissipative system.So the matching Gauss beam can be used as the incident beam to replace the bright DHSP beam, which is more convenient in theory and experiment.
Analysis of large refractive index difference of GRIN-rod lenses caused by ion-exchanging
Authors: Wang Feng  , Liu De-Sen  , Jiang Xiao-Ping  , Zhou Su-Mei  ,   (1)西南大学光电技术研究所,重庆 400715; (2)重庆师范大学初等教育学院,重庆 400700
Published: December 2020

The GRIN-rod lenses are made by two steps ion-exchanging, and the refractive index distribution of the sample is measured by the YaMing interferometer. The results show large differences in the refractive index of the samples. The reason for the increase of the refractive index difference by two-step ion-exchanging is discussed. The results of this research may help to produce GRIN materials.
Rapid enthalpy probe
Authors: Zhao Tai-Ze  , Wang Fei  , Guo Shao-Feng  , Guo Wen-Kang  , Xu Ping  ,   复旦大学现代物理研究所，上海 200433
Published: December 2020

Traditional enthalpy probe system use the Mass Flux Controller (MFC) to measure the flux rate of sample gas. However, this method much depend on the composition of plasma working gas under the condition of steady state of sample gas inside the probe, so it takes much more time to measure the enthalpy of a point. In order to overcome the disadvantage of traditional probe, the rapid enthalpy probe system we devised measure the molar weight of sample gas by using a known volume gas container instead of MFC, making it possible to measure the enthalpy of one point in several seconds. The accuracy of result acquired by our rapid enthalpy probe system is verified through our four different experiments.
Critical fracture behavior of high purity aluminum under impact loading
Authors: Qi Mei-Lan  , He Hong-Liang  , Yan Shi-Lin  ,   (1)武汉理工大学理学院，武汉 430070; (2)武汉理工大学理学院，武汉 430070；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实验室，绵阳 621900; (3)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实验室，绵阳 621900
Published: December 2020

One-dimensional strain impact experiments were performed for the high purity aluminum (HPA) (99.999%). The spall characteristics of HPA in dynamic tensile fracture have been discussed according to the quantitative metallographic analysis of the shock recover of samples. By defining the product of the tensile stress and the time as a parameter called tensile impulse (I), the statistic resultsindicate that an obvious critical behavior for the damage evolution appears with the increasing of I. When the I is low, the damage grows slowly with alinear increment. Once the I reaches a critical value, the damage grows rapidly and an exponential increase is observed. Our preliminary results indicate that the critical value of I for HPA is about 0.34 GPa·μs and the corresponding critical damage is about 0.12.
Electrical structures and optical properties of doped earth element (Y，La) in γ-Si3N4
Authors: Ding Ying-Chun  , Xiang An-Ping  , Xu Ming  , Zhu Wen-Jun  ,   (1)成都信息工程学院光电技术系，成都 610225; (2)成都信息工程学院光电技术系，成都 610225；四川师范大学物理与电子工程学院固体物理研究所，成都 610068; (3)四川师范大学物理与电子工程学院固体物理研究所，成都 610068；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重点实验室，绵阳 621900
Published: December 2020

The electronic structures and optical properties, the atomic population, bond lengths, band structures and density of states (DOS) of undoped and doped rare earth elements (Y, La) in γ-Si3N4 have been calculated by means of plane wave pseudo-potential method (PWP) with generalized gradient approximation (GGA). The gap after doping will decrease and enables the formation of new semiconductor，which affords to help finding new semiconductor. We researched optical properties after doping of rare earth elements (Y, La), and found that the static dielectric constant of doped γ-Si3N4 is much higher than that of the undoped material，which may serve as new dielectric and refractive material，and may have special applications in certain optical devices.
Effect of bivalent metal element doping on the electronic transport properties of LiCoO2
Authors: Kim Sung-Chol  , Huang Zu-Fei  , Ming Xing  , Wang Chun-Zhong  , Meng Xing  , Chen Gang  ,   (1)吉林大学材料科学与工程学院材料科学系，长春 130012; (2)吉林大学材料科学与工程学院材料科学系，长春 130012；朝鲜金日成综合大学物理系，平壤
Published: December 2020

In order to understand the different effects of Ca and Mg doping on the electronic transport properties of LiCoO2，which is the primary cathode material in Li-ion secondary batteries，the electronic structures of the relevant systems are studied with the ab initio method based on the density-functional theory. It is found that both Ca and Mg partial substitution for Co in LiCoO2 crystal will give rise to partially occupied acceptor band near the Fermi level，but these bands are substantially localized. Moreover，Ca-doped system has a clear energy gap between the acceptor band and the valence band，whereas for the Mg-doped system there isn't such a gap. It's believed that the existence of this gap is the main factor resulting in the non-significant increase of the electronic conductivity in the Ca-doped LiCoO2. In addition，the remarkable distinction in the ionic radii of Ca2+ and Mg2+ can also induce noticeably different effects on the electronic conductivities.
Tunneling conductance in quantum-wire/insulator/p wave superconductor junction
Authors: Li Xiao-Wei  ,   淮阴师范学院物理系，淮安 223001
Published: December 2020

Using Bogoliubov-de Gennes equations，we study the quasiparticle transport in quantum-wire/insulator/p wave superconductor junction (q/I/p). In the framework of the Blonder-Tinkham-Klapwijk model，we calculate the tunneling conductance in q/I/p as a function of the bias voltage at zero temperature and finite temperature. Differently from the case in quantum-wire/insulator/d wave superconductor junctions，there are zero-bias conductance peaks in the single-mode case. With the barrier strength becoming strong，the zero-bias conductance is gradually enhanced.
Re-entrant spin glass behavior in orthorhombic LiMnO2
Authors: Zhao Li-Zhu  , Chen Gang  , Li Feng-Yan  , Du Fei  , Wei Ying-Jin  , Huang Zu-Fei  , Wang Chun-Zhong  ,   (1)东北师范大学化学学院，长春 130024; (2)吉林大学材料科学与工程学院，长春 130012; (3)吉林大学材料科学与工程学院，长春 130012；东北师范大学物理学院，长春 130024
Published: December 2020

Orthorhombic LiMnO2 (o-LiMnO2) are synthesized by hydrothermal technique. Two samples were obtained which crystallize in orthorhombic structure with space group Pmnm. From rietveld refinements，the samples exhibit respectively a spot of cationic disorder on the lithium and manganese sites 4% and 8%，which，however，has no great influence on the magnetism. We have investigated the static and dynamical response of clusters in o-LiMnO2 oxide，and a sequenceof transformations of magnetic states，i.e. antiferromagnetic to ferromagnetic state at T≤TC≈118K and ferromagnetic to canted spin glass state at T≤Tf≈50K are observed.
Magnetoelectric cuopling in laminate composites Tb1－xDyxFe2－y and Fe-doped BaTiO3
Authors: Fan Jun-Feng  , Zhang Ning  ,   南京师范大学磁电子学实验室，南京 210097
Published: December 2020

Fe-doped BaTiO3 has been synthesized with sol-gel technique. The doped perovskite was found to have tetragonal structure. The transformation point of ferroelectric to paraelectric and the latent heat of the transformation were observed to be a little less than those for pure BaTiO3. Layered composites Tb1-xDyxFe2-y/Fe∶BaTiO3 have been fabricated. Their mgnetoelectric (ME) effect has been investigated. The transverse ME voltage coefficient for the bilayer Tb1-xDyxFe2-y-Fe∶BaTiO3 and the trilayer Tb1-xDyxFe2-y-Fe∶BaTiO3-Tb1-xDyxFe2-y can reach 6.225 adn 26.25mV·(A·m-1)-1·cm-1，respectively，under a bias magnetic field of 2.8×104A/m at room temperature，which are about 50% larger than those for the bilayer and trilayer composed of pure BaTiO3.
Analysis of self-collimation and subwavelength imaging in one-dimensional metal-dielectric structure
Authors: Zhang Jin-Long  , Liu Xu  , Li Yi-Yu  , Li Ming-Yu  , Gu Pei-Fu  ,   浙江大学现代光学仪器国家重点实验室，杭州 310027
Published: December 2020

The dispersion curve of one-dimensional metal-dielectric structure is calculated, and the finite-difference time-domain (FDTD) method is used to simulate the self-collimation in one-dimensional metal-dielectric structure, to which a Gaussian beam is incident at different angles. The influence of the dissipation of the metal layer on self-collimation is discussed. Subwavelength imaing with the one-dimensional metal-dielectric structure is also analyzed. The resolution of λ/8 is achieved for single point source when the thickness of 1DMD is equal to λ/2. The resolution will gradually degrade as the source moves beyond the near-field domain. Imaging with double slits source is also demonstrated, and a resolution of λ/3 is achieved.
The structure and photoluminescence properties of ZnO/silicon nanoporous pillar array
Authors: Yao Zhi-Tao  , Sun Xin-Rui  , Xu Hai-Jun  , Jiang Wei-Fen  , Xiao Shun-Hua  , Li Xin-Jian  ,   郑州大学物理系，材料物理教育部重点实验室，郑州 450052
Published: December 2020

Regularly arrayed nanocomposite system of zinc oxide/silicon nanoporous pillar array (ZnO/Si-NPA) was prepared by chemical vapor deposition utilizing Si-NPA as substrate, and the corresponding structure and photoluminescence properties were characterized. Our experimental results disclosed that all the pillars of ZnO/Si-NPA have a core-shell structure. Different from the red and blue emission from Si-NPA, two strong and wide emission bands were observed in the ultraviolet and blue-green ranges. These emission bands are attributed to the band-edge exciton transition of ZnO crystallites and two kinds of deep-level transitions originating from its intrinsic defects.
Electrical resistivity and mechanical properties of rapidly solidified Cu-Sn hypoperitectic alloys
Authors: Zhai Qiu-Ya  , Yang Yang  , Xu Jin-Feng  , Guo Xue-Feng  ,   西安理工大学材料科学与工程学院，西安 710048
Published: December 2020

The electrical resistivity, microhardness, tensile strength and elongation of rapidly solidified Cu-xwt.%Sn (x=7, 13.5, 20) hypoperitectic alloys are investigated, and the relationships between cooling rate and properties of the alloys are further analyzed theoretically. It is found that, under rapid solidification, the microstructure is refined and the amount of grain boundary increases, and the scattering of free electrons is thus intensified, resulting in the rise of alloy resistivity. Provided that the value of grain boundary reflection coefficient r is about 0.992, the electrical resistivity of the alloys can be theoretically analyzed by the M-S model. With the increase of cooling rate, the microhardness and tensile strength of alloy foils increase linearly, but the elongation decreases within the range of 1.0%—4.6%.
Damour-Ruffini method and nonthermal Hawking radiation from Reissner-Nordstrom black hole
Authors: Liu Wen-Biao  ,   北京师范大学物理学系，理论物理研究所，北京 100875
Published: December 2020

Taking into consideration the self-gravitational interaction and energy conservation, Hawking radiation from Reissner-Nordstrom black hole is re-investigated using the Damour-Ruffini method. It is found that the radiation is not exactly thermal, and the non-thermal Hawking radiation can carry information from the black hole. This can be used to explain the black hole information paradox, and the process satisfies the unitary thoery. A new method to calculate the corrected non-thermal Hawking radiation is given, which is more general. It can be used to study not only both the scalar field and Dirac field, but also massive and massless particle radiations.
The homotopic solving method of solitary wave for strong nonlinear evolution equation
Authors: Mo Jia-Qi  , Zhang Wei-Jiang  , Chen Xian-Feng  ,   (1)安徽师范大学,芜湖 241000；湖州师范学院,湖州 313000；上海高校计算科学E-研究院上海交通大学研究所,上海 200240; (2)上海交通大学,上海 200240；上海高校计算科学E-研究院上海交通大学研究所,上海 200240
Published: December 2020

A strong nonlinear evolution equation is studied. Using the homotopic mapping method, firstly, the corresponding homotopic mapping transform is constructed; secondly, the suitable initial approximation is selected; and thirdly, using the iteration method, the approximate solution with arbitrary degree of accuracy for the solitary wave is obtained.
Stochastic resonance control based on vibration resonance
Authors: Lin Min  , Huang Yong-Mei  ,   中国计量学院计量技术工程学院，杭州 310018
Published: December 2020

The dynamic characteristics of the non-linear bistable system subject to the action of high and low frequency signals were analyzed. The analytic formulation of the relationship between the parameters of high frequency signals and the SNR, spectral power amplification (SPA) of the bistable system output was presented. The stochastic resonance control method based on vibration resonance was proposed. The theoretical analysis and numerical simulation showed that the SNR and SPA of output signal of the bistable system can be controlled effectively by adjusting the amplitude and frequency of the high frequency signal.
Perturbation to symmetries and adiabatic invariant for nonholonomic controllable mechanical system in phase place
Authors: Xia Li-Li  , Li Yuan-Cheng  ,   中国石油大学物理科学与技术学院，东营 257061
Published: December 2020

This paper studies the perturbation to symmetries and the adiabatic invariant for nonholonomic controllable mechanical system in the phase space. The exact invariants introduced by the form invariance of the nonholonomic controllable mechanical system in phase space without perturbation are given. Based on the definition of high-order adiabatic invariants of the mechanical system, the perturbation to symmetries and the adiabatic invariant for nonholonomic controllable mechanical system in phase space under the action of small disturbance is investigated, then the form of high-order adiabatic invariants and the conditions for their existence are presented. An example is finally given to illustrate the application of the results.
Stability of relativistic rotational nonlinear dynamic equation and solution for a kind of nonlinear elastic coefficients
Authors: Meng Zong  , Liu Bin  ,   燕山大学电气工程学院，秦皇岛 066004
Published: December 2020

The nonlinear dynamic equation with two end faces in relativistic rotation is established, which contains a kind of nonlinear elastic force. The qualitative analysis of the relativistic rotational nonlinear autonomous equation is performed, and the stability of the equation is studied. The high-order approximate solution of the equation under forcing excitation is obtained by parameter transformation method.
The long-range scattering matrix of the recurrence spectra of NO molecules in strong field
Authors: Wang Ya-Jing  , Li Hong-Yun  , Xue Yan-Li  , Wang De-Hua  , Lin Sheng-Lu  ,   (1)鲁东大学物理与电子工程学院,烟台 264025; (2)青岛农业大学理学院,青岛 266109; (3)山东师范大学物理与电子科学学院,济南 250014
Published: December 2020

The scattering matrix approach to analyze the recurrence spectra of diatomic molecules in strong external magnetic field in the energy range E=77010—77050cm-1 is investigated. A new potential model is introduced to simplify the potential of the Rydberg electron of NO in external field. Based on the calculation of semiclassical orbits for the Rydberg states with rotation quantum number N=1,3,5, the long-range scattering matrix elements are obtained, which demonstrates that the quantum resonance peaks are intimately related to the corresponding closed orbits.
The dynamical resonance of a harmonic oscillator coupled to a heat bath with harmonic velocity noise and harmonic noise
Authors: Bai Zhan-Wu  , Song Yan-Li  ,   (1)华北电力大学数理系，保定 071003; (2)天津大学理学院,天津 300072
Published: December 2020

For a harmonic oscillator coupled to a heat bath with harmonic velocity noise and harmonic noise, we obtain the exact average energy by resoving the corresponding generalized quantum Langevin equation. Due to the different power spectra of the two kinds of noise, the harmonic oscillator driven by external harmonic force exhibits different resonant features. This is an approach for examing the characterization of internal noise.
Synchronization of chaotic systems with uncertainties using robust terminal sliding mode control
Authors: Huang Guo-Yong  , Jiang Chang-Sheng  , Wang Yu-Hui  ,   南京航空航天大学自动化学院,南京 210016
Published: December 2020

A novel robust terminal sliding mode control based on fast fuzzy disturbance observer is designed for a class of chaotic systems with uncertainties. To deal with the shortcoming of slow learning of traditional fuzzy disturbance observer when the approximation errors are very small, a fast fuzzy disturbance observer is designed which improves the learning speed. It is rigorously proved that the synchronization error and approximation error converge to very small values in finite time. Finally, simulation results of the Duffing-Holmes chaotic system demonstrate the effectiveness of the presented closed-loop control scheme.
Dynamical analysis of a new chaotic system and its chaotic control
Authors: Cai Guo-Liang  , Tan Zhen-Mei  , Zhou Wei-Huai  , Tu Wen-Tao  ,   江苏大学理学院，镇江 212013
Published: December 2020

In this paper a new chaotic system is presented. Some of its basic dynamical properties are studied. An electronic circuit is designed to realize the new chaotic system. Experimental chaotic behavior of the system is found to be identical to the dynamical properties predicted by theoretical analysis and numerical simulations. Based on Lyapunov stability theory, the new chaotic system is controlled by the method of adaptive backstepping. Numerical simulation shows the feasibility and effectiveness of this approach.
Parameter identification of first order time-delay chaotic system
Authors: Peng Hai-Peng  , Li Li-Xiang  , Yang Yi-Xian  , Zhang Xiao-Hong  , Gao Yang  ,   (1)北京邮电大学网络与交换技术国家重点实验室信息安全中心,北京 100876; (2)北京邮电大学网络与交换技术国家重点实验室信息安全中心,北京 100876；江西理工大学信息工程学院，赣州 341000
Published: December 2020

It's of vital importance to estimate the unknown parameters of chaotic systems in chaos control and synchronization. Nonlinear observer is used to investigate the problem of parameter identification for two different types of time-delay chaotic systems. The unknown parameter is regarded as the unknown state of the chaotic system. Based on the theory of nonlinear state observer, by selecting suitable nonlinear gain function in observer, which makes the closed-loop error system globally exponentially stable or approximately stable, a sufficient condition for existence of parameter estimator is presented. A numerical simulation on the well-known time-delay logistic system is conducted. Simulation results show that the proposed method is effective for parameter estimation of the time-delay chaotic system.
Chaotic synchronization problem of finite-time convergence based on fuzzy sliding mode
Authors: Liu Yun-Feng  , Yang Xiao-Gang  , Miao Dong  , Yuan Run-Ping  ,   (1)第二炮兵工程学院303教研室,西安 710025; (2)西安交通大学电信学院,西安 710049
Published: December 2020

The problem of finite-time synchronization for chaotic system is proposed. By applying the global sliding mode control technique and selecting the exponential fast terminal sliding mode reaching law, a global sliding mode controller is designed and applied to synchronization of a class of chaotic systems. Aimed at the chaotic system with parameter uncertainties and disturbance, fuzzy basis function network is introduced to on-line estimate the parameter bound. The design scheme eliminates the reaching phase of sliding mode control. The tracking error stays on the sliding mode surface and tends to zero in finite time. To verify the feasibility and effectivness of this control strategy, the synchronization for Duffing chaotic system is illustrated.
Adaptive chaos control with dead-zone and saturating input
Authors: Shen Qi-Kun  , Zhang Tian-Ping  , Sun Yan  ,   (1)扬州大学物理科学与技术学院，扬州 225002; (2)扬州大学信息工程学院，扬州 225009
Published: December 2020

The chaos tracking control problem is studied for a class of uncertain time-delay chaotic systems. Based on the principle of sliding mode control (SMC), a novel adaptive design scheme is proposed. The approach not only overcomes the drawback reported in the literature, but also removes the assumptions that the dead-zone is symmetric and the slopes are known. By theoretical analysis, it is shown that tracking error asymptotically converges to zero. Finally, simulation results of Duffing-Holmes chaotic system demonstrate the effectiveness of the proposed approach.
Generalized synchronization of hyperchaos systems
Authors: Wang Xing-Yuan  , Meng Juan  ,   大连理工大学电子与信息工程学院，大连 116024
Published: December 2020

The generalized synchronization of hyperchaos systems is investigated. Based on the Lyapunov stability theory, a new linear and nonlinear generalized synchronization approach is proposed. Theoretical analysis is provided to show its feasibility. The proposed method can realize the generalized synchronization not only of structurally equivalent systems, but also of systems of different dimensions. If the error gain matrix is suitably chosen, the generalized synchronization between drive system and response system will be obtained. Numerical simulations further demonstrate the effectiveness of the proposed scheme.
A Z-trap in an atom chip for trapping neutral 87Rb atoms
Authors: Li Xiao-Lin  , Ke Min  , Yan Bo  , Tang Jiu-Yao  , Wang Yu-Zhu  ,   (1)浙江大学物理系，杭州 310027; (2)中国科学院上海光学精密机械研究所量子光学重点实验室，上海 201800；中国科学院冷原子物理中心，上海 201800
Published: December 2020

Trapping potential of a Z-trap is calculated with analytic and numeric methods. It's found that when a trapping center is a little bit far from the chip surface (the distance is about one order of the half length of the Z-wire central part), the trapping depth is not approximately eqsual to the potential By created by a bias magnetic field, the potential energy at the trapping center should be subtracted from the potential By created by the bias field. On the other hand, if an atom cloud is compressed to a certain extent by increasing By, the trapping depth will be decreased rather than increased. The preparation of the Z-trap in an atom chip, the experimental setup, and the experimental procedure for trapping neutral 87Rb atoms is also introduced. At last we obtained 2×106 87Rb atoms trapped in the Z-trap.
Experimental study of ultracold cesium atom photoassociation spectrum using an amplitude modulation technique
Authors: Wang Li-Rong  , Ma Jie  , Zhang Lin-Jie  , Xiao Lian-Tuan  , Jia Suo-Tang  ,   量子光学与光量子器件国家重点实验室，山西大学物理电子工程学院，太原 030006
Published: December 2020

A high resolution photoassociation spectrum of ultracold cesium atoms is reported in this paper. A photoassociation laser with its frequency red detuned below 6S1/2+6P3/2 dissociation limit acts on the cold cesium atoms in magnetic optical trap and the excited ultracold molecules generated in the photoassociation process are observed. In order to obtain a high signal-to-noise ratio, the trapping laser is amplitude modulated using acousto-optic modulator and the fluorescence signal is demodulated by lock-in technique. The results are discussed using the density matrix equations.
Second-harmonic generation in nonlinear left-handed metamaterials
Authors: Chen Liang  , Liang Chang-Hong  , Dang Xiao-Jie  ,   西安电子科技大学天线与微波技术国家重点实验室，西安 710071
Published: December 2020

Based on the electromagnetic theory，the Manly-Rowe relations for nonlinear left-handed metamaterials are studied. Energy conversion process and spatial distribution of forward-propagating wave of fundamental frequency and backward-propagating second harmonic wave under phase-matching condition are investigated. That a surface of nonlinear left-handed metamaterials operates as an effective mirror which reflects the energy in the form of second harmonics is demonstrated. Numerical results of field intensity distribution of a finite thickness metamaterial slab is given. Finally，the importance of phase-matching condition to the investigation of nonlinear left-handed metamaterials is illustrated from the viewpoint of phase-mismatching. This work provides a basis for studying nonlinear left-handed metamaterials.
Far-field focusing properties of two-dimensional honeycomb photonic crystals and the effect of the interface
Authors: Li Guo-Jun  , Kang Xue-Liang  , Li Yong-Ping  ,   (1)中国科学技术大学物理系，合肥 230026; (2)中国科学技术大学物理系，合肥 230026；中国科学院量子信息重点实验室，合肥 230026
Published: December 2020

The far-field focusing properties of two dimensional rod-type honeycomb lattice photonic crystals are investigated by using finite difference time domain method，and it was found that it explicitly follows the wave-beam negative refraction law with relative refractive index of -1. But the image qualities are limited by low transmission at large incident angles. The image qualities can be improved by modifying the radius of rods near the surface of photonic crystals slab.
Research on optical feedback characteristics of frequency modulated microchip Nd:YAG lasers
Authors: Tan Yi-Dong  , Zhang Shu-Lian  ,   清华大学精密测试技术与仪器国家重点实验室，北京 100084
Published: December 2020

Optical feedback characteristics of frequency modulated microchip Nd：YAG lasers are investigated. Without optical feedback，the output intensity changes by one fringe with the laser frequency changing by one longitudinal mode spacing. With optical feedback，the modulation frequency of output intensity is proportional to the ratio of external cavity length to internal cavity length. The theoretical analysis based on three-cavity-mirror equivalent model is in good agreement with experimental results. The potential applications of this phenomenon in precision measurement are also discussed.
Study of SNR of a novel polarization interference imaging spectrometer
Authors: Yuan Zhi-Lin  , Zhang Chun-Min  , Zhao Bao-Chang  ,   (1)西安交通大学理学院，西安 710049; (2)中国科学院西安光学精密机械研究所，西安 710068
Published: December 2020

Based on radiometry，electromagnetism and polarization theories and the Fourier transform spectroscopy，an in-depth study is conducted on the SNR of the self-developed ultra-compact static polarization interference imaging spectrometer (USPIIS) theoretically and experimentally. The theoretical equations of its SNR are deduced. Under paraxial approximation，the curve of the SNR changing with incidence angle is given via computer simulation. How the polarizing directions affect the SNR of USPIIS，which is a particular feature of the polarization interference imaging spectrometer，is deeply studied. When modulation depth equals 0.6，0.7，0.8，0.9 and 1.0，the curves of the SNR changing with polarizing directions are given respectively; after which the optimum value is recommended. Under optimum conditions，the changing laws of SNR with the elements of detector are obtained，which turned out the same as the prediction of the theory. The theoretical and experimental results both indicate that the novel imaging spectrometer has the properties of high throughput and high SNR under the condition of high modulation depth，which is suitable for aviation，remote sensing，weak signal testing applications. The work can provide theoretical basis and guidance for the design，development and engineering of polarizer，interferometer and polarization imaging interferometer.
A phase modulated QKD system with two quantum cryptography protocols
Authors: Chen Xia  , Wang Fa-Qiang  , Lu Yi-Qun  , Zhao Feng  , Li Ming-Ming  , Mi Jing-Long  , Liang Rui-Sheng  , Liu Song-Hao  ,   华南师范大学信息光电子科技学院，光子信息技术广东省高校重点实验室，广州 510631
Published: December 2020

An improved DPS-QKD scheme is proposed and demonstrated in this paper. At Alice's site，we use a M-Z interferometer to produce two coherent pulses. At Bob's site，a Faraday-mirrors-based Michelson interferometer is used instead of a M-Z interferometer to auto-compensate for the phase drifts and polarization mode dispersions in the fiber. It enhances the security of the whole system to use the two quantum cryptography protocols (namely the two pulse DPS-QKD scheme associated with the BB84 scheme). It is shown in our experiment that such a system features perfect stability with a quantum bit error rate less than 5% and high key generation rate. This scheme has been implemented successfully during the 80km fiber transmission.
High energy chirped pulse characteristics observed by spectral-resolved streak camera
Authors: Xie Xu-Dong  , Wang Xiao  , Zhu Qi-Hua  , Zeng Xiao-Ming  , Wang Feng-Rui  , Huang Xiao-Jun  , Zhou Kai-Nan  , Wang Fang  , Jiang Dong-Bin  , Huang Zheng  , Sun Li  , Liu Hua  , Wang Xiao-Dong  , Deng Wu  , Guo Yi  , Zhang Xiao-Mi  ,   中国工程物理研究院激光聚变研究中心，等离子体物理国家级重点实验室，绵阳 621900
Published: December 2020

We observed the characteristics of high energy nanosecond chirped pulse by spectral-resolved streak camera，which works well with energetic chirped pulse of nanosecond pulse duration. At the same time，it can monitor the alignment of grating compressor. The measurement results show that the pulse generated by PW demonstration facility is linearly chirped，verifying the compressibility of amplified nanosecond pulse.
Group-velocity-matching relation in the mixing process of broadband third-harmonic generation
Authors: Yang Yi-Sheng  , Zheng Wan-Guo  , Han Wei  , Che Ya-Liang  , Tan Ji-Chun  , Xiang Yong  , Jia Huai-Ting  ,   (1)国防科学技术大学理学院，长沙 410073; (2)中国工程物理研究院激光聚变研究中心，绵阳 621900; (3)中国工程物理研究院激光聚变研究中心，绵阳 621900；国防科学技术大学理学院，长沙 410073; (4)中国工程物理研究院激光聚变研究中心，绵阳 621900；西安通信学院光纤教研室，西安 710106
Published: December 2020

Based on the nonlinear coupling equations，the relation between group-velocities of 1ω，2ω and 3ω waves in the mixing process of broadband third-harmonic generation (THG) is investigated theoretically. The formula of three-wave group-velocity-matching (GVM) is derived. The THG mixing process of ultrashort pulses in Type-Ⅱ KDP crystals is simulated. Obtained results show that both the THG conversion efficiency and the bandwidth reach maximum when the formula is satisfied (i.e., at zero group-velocity mismatch)，and drop down rapidly when it's not satisfied. The three-wave GVM formula presented is useful for finding proper nonlinear crystals and choosing effective GVM methods.
Properties of the fused silicon fiber-reflector
Authors: Yu You-Long  , Cao Xue  , Liu Sheng-Chun  , Chen Xue-Feng  ,   (1)合肥工业大学仪器科学与光电工程学院，合肥 230009；黑龙江大学光纤技术研究所，哈尔滨 150080; (2)黑龙江大学光纤技术研究所，哈尔滨 150080
Published: December 2020

Within the range from 0 to 1，the transmissivity of fused tapered fiber reflector as a conic function of the departure of the coupling-ratio from 50∶50 was examined theoretically and experimentally. Bending the fiber in loop-cavity causes no obvious change. However，twist and the radial pressure change the transmissivity，obviously，producing birefringence in the fiber core. Temperature changes the transmissivity through the induced departure of the coupling-ratio. Constructed with a broad-band 3dB fused tapered fiber coupler，the reflector shows total reflection. A pulse was observed at the beginning of the formation of the transmitted beam. Increasing the input intensity causes，the rise-time and the fall-time of the pulse to decrease, while the width of the pulse and the steady state value of the transmitted power to increase.
Mechanical effects during interaction of pulsed laser and metal in fluids in viscosity range of 10－6 to 10－4m2/s
Authors: Liu Xiu-Mei  , Zhao Rui  , He Jie  , Lu Jian  , Ni Xiao-Wu  ,   南京理工大学应用物理系，南京 210094
Published: December 2020

A novel force sensor based on optical beam deflection was developed to investigate the mechanical effects during the pulsed laser ablation of a metal in liquids with different viscosities. The experimental results show that the targets in viscous liquids are affected by laser-generated ablation force and high- speed liquid-jet impulse induced by bubble collapse. In the same liquid, the amplitudes of the three kinds of forces increase with the increase of laser energy. With the increase in viscosity, the amplitudes of all three forces decrease, and the cavitation erosion is reduced. Larger viscosities make the bubble expand or contract more slowly, and bubble life-time becomes larger. Besides, the Rayleigh equation was revised, and the results are in good agreement with the experimental data.
Zirconium-ion implantation of zircaloy-4 investiged by slow positron beam
Authors: Hao Xiao-Peng  , Wang Bao-Yi  , Yu Run-Sheng  , Wei Long  ,   (1)中国科学院高能物理研究所核分析技术重点实验室，北京 100049; (2)中国科学院高能物理研究所核分析技术重点实验室，北京 100049；中国科学院研究生院，北京 100049
Published: December 2020

The effect of Zr-ion implantation into zircaloy-4 and the defect recovery was investigated by slow positron beam. Specimens were implanted by zirconium ions with doses ranging from 1×1015 to 1×1017 ions/cm2 using a MEVVA source at an extract voltage of 50 kV. It was found that defects in the samples irradiated with a dose above 1×1016 ions/cm2 has been recovered during the implantation process, and the thickness of oxide layer increases as indicated by auger electron spectroscopy (AES) measurements. Meanwhile, the defects in the sample implanted with a dose of 1×1015ions/cm2 turns out to be recovered after annealing at 300℃ in high vacuum for 1 hour, showing the corresponding the recovery energy of defects is very low. We propose the method of keeping the material at an appropriate temperature during implantation to improve the corrosion resistance of Zr-4 alloy, according to the relationship between the defect concentration and the corrosion resistance.
Shock-induced phase transition of z-cut lithium tantalate single crystal
Authors: Li Jun  , Zhou Xian-Ming  , Li Jia-Bo  , Li Sai-Nan  , Zhu Wen-Jun  , Wang Xiang  , Jing Fu-Qian  ,   中国工程物理研究院流体物理研究所冲击波与爆轰物理重点实验室，绵阳 621900
Published: December 2020

High-pressure phase-transition behaviors of z-cut lithium tantalate single-crystal have been studied by Hugoniot measurements at our two-stage light-gas gun and DFT-PWP calculations. A distinct discontinuity was discovered on the D-u (shock-wave velocity versus particle velocity) relation. An elastic-plastic two-wave structure was observed from the VISAR measured particle velocity profiles at low pressures (25.9 GPa and 32.6 GPa), while three-wave structure appeared in the measured particle velocity profiles at the final pressure of 42.9 GPa and 53.0 GPa. Both facts indicate a shock-induced phase transition of LiTaO3 samples occurred with an onset pressure of 37.9GPa. The theoretically calculated 0K pressure versus compression ratio (P-V/V0) curve for the rhombohedral phase (R3c space group) is in good agreement with the low-pressure experimental data, while that for orthorhombic phase (Pbnm space group) is in accord with the results by deducing thermal pressure contribution from the measured shock-compression data at high pressures. This suggests that the high-pressure phase has orthorhombic symmetry. High-pressure phase transformation behaviors including the transition pressure and structures, which are unclear in current literature, have been clarified in this paper by our new shock-wave data and ab-initio calculations. These behaviors were demonstrated to be in close similarity with that of its isomorphous crystal LiNbO3. The present work is significant for the investigations of shock-induced phase-transition of similar single-crystal materials.
The dipole interaction model of the molecular aggregation in Y-type Langmuir-Blodgett film
Authors: Bai Lei  , Han Kui  , Tang Gang  , Li Hai-Peng  , Wang Hong-Tao  , Huang Zhi-Min  , Zhang Zhao-Hui  ,   中国矿业大学理学院，徐州 221008
Published: December 2020

Based on the classical electrostatic theory, the model of dipole-dipole interaction of rod-like amphiphilic molecules in Y-type Langmuir-Blodgett (LB) film is presented in the paper. The relations between the structure and spectral absorption peak of LB films were obtained by using this model. For Y-type films, the relationship of molecular aggregation state and the structure parameters, i.e. molecular separation distance a, separation d between two adjacent layers, molecular tilt angle θ, and layer number　g, were studied using our model. Then we compared the similarities and differences of aggregation behavior between Y-type and Z-type films. The theoretical results agree well with experimental data.
Strain relaxation in heteroepitaxial islands of Au/Cu(111) and Ag/Cu(111) systems and its effects on the formation of Moiré structure
Authors: Yan Chao  , Zhang Chao  , Tang Xin  , Meng Yang  , Zhang Qing-Yu  ,   大连理工大学三束材料改性国家重点实验室,大连 116024
Published: December 2020

Molecular dynamics simulation was used to study the strain relaxation and evolution of Ag/Cu(111) and Au/Cu(111) heteroepitaxial systems with embedded atom method. By comparing the evolution behaviors of the two systems, the atomistic mechanism leading to the formation of Moir structure in Ag/Cu(111) epitaxial layer is studied and is related to the physical properties of the components in the heteroepitaxial system. It is found that the adhesion between epilayer and substrate is one of the important factors that affect the formation of Moir structure. Positive solution heat of the alloy enables the adhesion of heteroepitaxial system to be weak and is helpful for the formation of Moir structure. The relaxing ability of atoms in epilayer is also important in the formation of Moir structure, which can be related to the bulk modulus of epilayer. The larger the bulk modulus of epilayer, the easier the formation of Moir structure. On the other hand, the formation of Moir structure is related to the island size, which is caused by the boundary atoms confining the relaxation of interior atoms in the island.
The spectral fine structure, zero-field splitting parameters and Jahn-Teller effect of LiNbO3∶Fe3+crystals
Authors: Lü Hai-Ping  , Yin Chun-Hao  , Wei Xue-Song  , Niu Ying-Xi  , Song Ning  , Ru Rui-Peng  ,   中国矿业大学理学院，徐州 221008
Published: December 2020

The 252 rank completely diagonalized Hamiltonian matrix of the 3d5 configuration with trigonal symmetry have been established by group theory, crystal field theory and irreducible tensor operator method. The spectral fine structure, zero-field splitting parameters, and Jahn-Teller effect, as well s the influence of spin doublet state and spin quartet state on the ground-state energy levels in LiNbO3∶Fe3+ crystals were studied with this matrix. The results show that the contribution of spin quartet state on the ground- state energy levels is the most important, the contribution of spin doublet state is weak but can not be neglected. The calculated results are in good agreement with the experiments. On their basis, the influence of spin-orbit interaction and spin-spin interaction on the spectra fine structure and zero-field splitting parameters were further studied, and we found that the influence of spin-orbit interaction is dominant, but the influence of spin-spin interaction can not be neglected. The research shows this substance has J-T effect in the spectral structure of spin quartet state. The reason is the combined action of spin-orbit interaction and trigonal distortion.