bluuebunny/crossref_metadata_2025 huggingface dataset:
Thermoelectric transport properties of Zn-doped n-type Ba8Ga16-2xZnxGe30+x clathrates
Authors: Xiong Cong  , Deng Shu-Kang  , Tang Xin-Feng  , Qi Qiong  , Zhang Qing-Jie  ,   武汉理工大学材料复合新技术国家重点实验室，武汉  430070
Published: December 2020

The single-phase Zn-doped n-type Ba8Ga16-2xZnxGe30+x clathrates were prepared by melting reaction method combined with spark plasma sintering (SPS). Influences of substituting Zn for Ga on the thermoelectric transport properties of the compounds were investigated. Research results indicate that the electrical conductivity of n-type Ba8Ga16-2xZnxGe30+x compounds increases gradually with the increasing of Zn substitution fraction x. The Seebeck coefficient decreases gradually with the increasing of x. When Zn replaces Ga entirely, the electrical conductivity of Ba8Zn8Ge38 compound drops rapidly and its Seebeck coefficient increases suddenly. Zn substitution fraction x dependence of the thermal conductivity and lattice thermal conductivity are similar in the temperature range from 300 to 1000 K.When xx,lattice thermal conductivity decreases gradually. When x>4, with the increase of x,lattice thermal conductivity increases gradually.In all n_type Ba8Ga16-2xZnxGe30+x clathrates, Ba8Ga8Zn4Ge34 compound has the greatest ZT value, and its maximal ZT value reaches 085 at about 1000K.
Tunneling magnetoresistance of Fe3O4 compacts prepared in magnetic field
Authors: Wang Jing-Ping  , Meng Jian  ,   (1)哈尔滨工程大学材料科学与化学工程学院，哈尔滨  150001; (2)中国科学院长春应用化学研究所稀土化学与物理重点实验室，长春  130022
Published: December 2020

The magnetite particles were prepared in magnetic field in order to improve the surface crystallinity and reduce the lattice defests of particles. The magnetotransport properties of as-prepared magnetite compact were investigated and compared with that prepared without magnetic field. Spin polarization tunneling and high order hopping conductance were the main conduct mechanisms. The resistance decreased almost exponentially with increasing temperature, and was noncollinearity dependent on the voltage. Magnetoresistance vs magnetic field curves were butterfly-like, which was characteristic of tunneling magnetoresistance. The results showed that the sample prepared in magnetic field had lower resistance and higher magnetoresistance, maybe due to the particles having better crystallinty in the surface and less lattice defect. Magnetoresistance of both samples decreased slowly with increasing temperature.
Optimization of seed layer of PbTiO3/PbZr0.3Ti0.7O3/PbTiO3 sandwich structure ferroelectric thin film
Authors: Wang Long-Hai  , Yu Jun  , Wang Yun-Bo  , Gao Jun-Xiong  , Zhao Su-Ling  ,   (1)华中科技大学电子科学与技术系,武汉  430074; (2)武汉理工大学材料研究与测试中心，武汉  430070
Published: December 2020

The PT/PZT/PT and PZT thin films were prepared by sol-gel method. Different Pb content (x) (x=0, 005, 010, 015, 020) were added in excess to the PT precursor to optimize PT seed layer. The XRD and AFM results show that the crystalline phase and microstructure of the films were greatly affected by the excess Pb content (x) in PT layers. The pure perovskite structure PT/PZT/PT films with dense, void-free and uniform fine grain size were obtained for the proper choice of excess Pb content (x=010—015). EDX results showed that, in the interlayer and surface regions, the Pb deficiently and Pb abandance are obvious for the samples of x=0 and x=02, respectively. The ferroelectric, fatigue and leakage current properties of the films are not obviously relate to the change of excess Pb content (x), but correlate obviously with the crystalline behavior of PT layers. A well-saturated hysteresis loop with high remnant polarization, excellent fatigue properties and low leakage curremt were obtained for the films of excess Pb content x= 010 and 015. The excess Pb content (x) in PT layers affects the crystallization of PT layer, which will act as a nucleation site or seeding layer for PZT films and affect the perovskite phase formation of the PZT films. The optimized seed layer with excess Pb content x=010—015 improves not only the microstructure, but also the electric properties.
Dependence of properties of GaN-based light emitting diodes on the surface InGaN thickness
Authors: Gu Xiao-Ling  , Guo Xia  , Wu Di  , Li Yi-Bo  , Shen Guang-Di  ,   北京工业大学，北京市光电子技术实验室，北京  100022
Published: December 2020

GaN-based light emitting diodes (LEDs) with InGaN as the capping layer was designed in our experiment. The forward voltage at the typical driving current of 20mA was obviously changed by adjusting the thickness of the InGaN layer. We were concerned with the effect of polarization and solved the concentration and the tunneling probability of the two dimensional hole in the triangular potential well at the surface InGaN/GaN interface and obtained the minimal forward voltage. The calculation results were consistent with the experimental data.
Preparation of tetrapod-shaped ZnO nanomaterial field emission cathodes by deposition method
Authors: Qin Hua-Fang  , Guo Tai-Liang  ,   福州大学化学化工学院，福州  350006
Published: December 2020

Tetrapod-shaped ZnO nanomaterial field emission cathode was preparated by deposition method. To the high-vacuum flat capsulation with phosphor screen and cathode was applied a voltage to test the cathode emission current and the phosphor screen brightness. For the cathode with total area 13×15 cm2, the test results showed that when the volume percentage of K2SiO3 ranged from 50 × 10-3 to 83× 10-3, concentration of Ba(NO3)2 arranged from 50 × 10-4 to 77×10-4 M, and concentration of tetrapod-shaped ZnO arranged from 82×10-4 to 12×10-3M, the cathode emission current was the largest, and phosphor screen at peak brightness could reach 60 cd/cm2 The average brightness was 48 cd/cm2
Non-ionizing energy loss of low energy proton in semiconductor materials Si and GaAs
Authors: Tang Xin-Xin  , Luo Wen-Yun  , Wang Chao-Zhuang  , He Xin-Fu  , Zha Yuan-Zi  , Fan Sheng  , Huang Xiao-Long  , Wang Chuan-Shan  ,   (1)上海大学理学院，上海  200444；中国原子能科学研究院,北京  102413; (2)上海大学射线应用研究所，上海  201800; (3)上海大学射线应用研究所，上海  201800；上海大学理学院，上海  200444; (4)中国原子能科学研究院,北京  102413
Published: December 2020

The displacement damage due to non_ionizing energy loss (NIEL) is the main reason of device-malfunction in spatial radiation environments. In the low energy range where the Coulombic interaction dominates, Mott-Rutherford differential cross section is usually used in its creatment. However, electrostatic screening of nuclear charges of interacting particles is not accounted for. The NIEL induced by low energy proton in Si and GaAs have been calculated using analytical method and Monte-Carlo code (SRIM). Thin_target approximation was used when calculating NIEL by SRIM code and the result compared with that of other authors' . The results show that thin_target approximation is reasonable and NIEL scaling is feasible. The NIEL values become lower after taking into account the screening effect. The results by SRIM code are 30% and 20% of Summers's results for Si and GaAs at 1 keV, respectively. The result is very important for spacecraft design.
Chaotic motion of some relative rotation nonlinear dynamic system
Authors: Shi Pei-Ming  , Liu Bin  , Hou Dong-Xiao  ,   燕山大学信息科学与工程学院，秦皇岛  066004
Published: December 2020

The chaotic motion of a relative rotation nonlinear dynamic system possessing both homoclinic and heteroclinic orbits is investigated. Firstly, the dynamics equation of relative rotation nonlinear dynamics system with nonlinear stiffness and nonlinear damping and forcing excitation is deduced. Secondly, a global bifurcation of the system and a probable route leading to chaos have been discussed by using Melnikov method, and the necessary condition of chaotic motion of system is presented. The chaotic motion of system is complemented by top Lyapunov exponents maps, bifurcation maps, Poincare maps and phase plane plots.
Teleportation of on N-particle GHZ state via one three-particle W state
Authors: Zha Xin-Wei  , Zhang Chun-Min  ,   (1)西安交通大学理学院，西安  710049; (2)西安邮电学院应用数学与应用物理系, 西安  710061
Published: December 2020

Recently Yang Hon-qin et al proposed a scheme for teleporting a three-particle GHZ state from a sender to either of two receivers with two three-particle W state quantum channel. In this paper, the theoretical analysis is given and the new scheme for teleporting an N- particle GHZ state using only one three-particle W state quantum channel is proposed.
Bright soliton solution in 1D Tonks-Girardeau gas
Authors: Liu Hong  , Wei Jia-Yu  , Lou Sen-Yue  , He Xian-Tu  ,   (1)北京物资学院物流学院，北京  101149; (2)北京应用物理与计算数学研究所，北京  100088; (3)宁波大学理学院，宁波  315211; (4)中国工程物理研究院研究生部，北京  100088
Published: December 2020

Base on spherical symmetric trap treatment, we analyze how to change a generalized Gross-Pitaevskii equation to a quintic nonlinear Schrdinger equation. Analysing the nonlinear Schrdinger equation, we find a typical bright soliton solution in Tonks-Girardeau gas region. This will help experimental observations.
The design of entangled source for free space quantum communications
Authors: Wang Shao-Kai  , Ren Ji-Gang  , Jin Xian-Min  , Yang Bin  , Yang Dong  , Peng Cheng-Zhi  , Jiang Shuo  , Wang Xiang-Bin  ,   (1)清华大学物理系,北京  100084; (2)中国科学技术大学近代物理系,合肥  230026
Published: December 2020

We design and build an entanglement source suitable for free space quantum communications experiment. The coincidence counting rate after single mode fiber is 20000 cps. The entanglement visibility is more than 95% in horizontal vertical base and more than 90% in diagonal base. The Bell inequality was broken by more than 100 standard deviations in local experiment. The entanglement source satisfies the requirements for 20 km free space quantum communications experiment.
Transient properties of a tumor cell growth system driven by color Gaussian noises: Mean first-passage time
Authors: Wang Can-Jun  , Wei Qun  , Zheng Bao-Bing  , Mei Dong-Cheng  ,   (1)宝鸡文理学院非线性研究所,宝鸡  721007; (2)宝鸡文理学院非线性研究所,宝鸡  721007；云南大学物理系, 昆明  650091; (3)云南大学物理系, 昆明  650091
Published: December 2020

The transient properties (mean first passage time T)of the tumor cell growth system driven by color Gaussian noise are investigated. The approximate Fokker-Planck Equation is obtained based on the Novikov theorem and the Fox approach and the explicit expression of the mean first passage time is derived. The numerical computation results show that T behaves with different characters in the cases of 0λλλλT exhibits complex behavior, namely T has one maximum with the multiplicative noise intensity D and its self-correlation time τ1 increasing.
Chaotic point process description of converter discrete subsystem and EMI suppression
Authors: Yang Ru  , 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；广州大学物理与电子工程学院, 广州  510400
Published: December 2020

The converter is described as a continuous-discrete system based on hybrid system theory. According to the theory of chaotic PWM, chaotic point process model of converter is established. Chaotic PWM control is done with piece-wise chaotic maps. The characteristic function and distribution of chaotic PWM are obtained, the spectrum of chaotic PWM and periodic PWM are obtained too. Experimental results verify that the peak spectrum of chaotic converter can be suppressed with stable output, and EMI is improved distinctly.
Nonlinear observer based full-state projective synchronization for a class of fractional-order chaotic system
Authors: Chen Xiang-Rong  , Liu Chong-Xin  , Li Yong-Xun  ,   西安交通大学电气工程学院，电力设备电气绝缘国家重点实验室,西安  710049
Published: December 2020

In this paper, based on the stability theory of the fractional-order system, an idea of using state observer to realize the full-state projective synchronization of fractional-order chaotic system is proposed. The designed observer can achieve full-state projective synchronization in a class of nonlinear fractional-order systems without the limitation of partial-linearity, extend the scope of application of projective synchronization, and does not require the calculation of the conditional Lyapunov exponents. In addition, this synchronization method is simple and theoretically rigorous, capable to achieve a full-state synchronization of arbitrary scaling factor. Finally, the method has been applied to realize the full-state projective synchronization of fractional-order Rssle system, and the simulation results verified the effectiveness of the method.
A test method for weak nonlinearity in time series
Authors: Jiang Ke-Yu  , Cai Zhi-Ming  , Lu Zhen-Bo  ,   海军工程大学电子工程学院，武汉  430033
Published: December 2020

Nonlinearity is necessary for time series to be treated as chaotic time series. A new test statistic for nonlinearity, which is based on the ratio of the multistep normalized prediction error with respect to linear AR models and nonlinear AR models, is used to detect the weak nonlinear components contained in time series by the surrogate data method. Taking example for Lorenz time series, the effect of related parameters for test statistic estimation is analyzed. By the nonlinearity tests for chaotic time series, the proposed test statistic δNAR has better discrimination power for weak nonlinearity than the test statistic δAIC based on AIC rules and the zeroth order nonlinear prediction error δZP, which shows that the proposed test statistic has strong adaptive abilities for time series. And, for different time series, the parameters with best nonlinearity discrimination performance are kept constant. The stabilization of parameters facilitates the nonlinearity test for other time series.
Improving chaotic carrier fundamental frequency in VCSELs with optical feedback by strong light injection
Authors: Liu Sheng-Fang  , Xia Guang-Qiong  , Wu Jia-Gui  , Li Lin-Fu  , Wu Zheng-Mao  ,   西南大学物理学院，重庆  400715
Published: December 2020

In this paper, the influence of the external light injection on the chaotic carrier fundamental frequency of vertical-cavity surface-emitting lasers (VCSELs) with optical feedback have been investigated. The results show that, for the fixed frequency offset between the master laser diode and the slave VCSEL, the chaotic carrier fundamental frequency will generally increase with the increase of injection intensity; the chaotic carrier fundamental frequency can be improved significantly by adjusting frequency offset and injection intensity. For the normalized injection intensity K of 330 and frequency offset 42 GHz, chaotic output with 47.3GHz fundamental frequency can be obtained.
Bifurcations of safe basins and chaos in Flickering oscillator under multi-frequency harmonic and bounded noise excitation
Authors: Rong Hai_Wu  , Wang Xiang-Dong  , Xu Wei  , Fang Tong  ,   (1)佛山大学数学系，佛山  528000; (2)西北工业大学应用数学系，西安  710072
Published: December 2020

The erosion of the safe basins and related chaotic motions of a Flickering oscillator under multi-frequency external periodic forces and bounded random noise are studied. By the Melnikov method, the system's Melnikov integral is computed and the parametric threshold for the onset of chaos is obtained. The Melnikov's global perturbation technique is therefore generalized to higher dimensional systems. Using the Monte-Carlo and Runge-Kutta method, the erosion of safe basins is also discussed. As an alternative definition, stochastic bifurcation may be defined as a sudden change in the character of stochastic safe basins when the bifurcation parameter of the system passes through a critical value. This definition applies equally well either to randomly perturbed motions or to purely deterministic motions. It is found that increasing the number of forcing frequencies or increasing the random noise may destroy the integrity of the safe basins, bring forward the occurrence of the stochastic bifurcation and make the threshold for onset of chaos vary in a larger extent,which hence makes the system less safe and chaotic motions easier to occur.
Mass exponent spectrum analysis of human ECG signals based on multiple scale factors
Authors: Yang Xiao-Dong  , Ning Xin-Bao  , He Ai-Jun  , Du Si_Dan  ,   南京大学电子科学与工程系，生物医学电子工程研究所，南京  210093
Published: December 2020

Life is one of the most complex nonlinear systems and heart is the core of this lifecycle system. The complexity of electrocardiogram (ECG) signals may reflect the physiologic function and health status of the heart. In this paper, we introduced two novel parameters of the multifractal mass exponent spectrum curvature and area. The evaluation of Cantor set validated that the two indicators are entirely effective in exploring the complexity of chaotic time series. Using the multiscale analysis method, we studied the mass exponent spectra of ECG signals taken from the cohorts of healthy, ischemia and myocardial infarction (MI) sufferer under different sampling frequencies and data lengths. Then we compared these new indicators with other nonlinear parameters and also expected to acquire some valuable nonlinear eigenvalues to distinguish the healthy from the heart diseased through those individual discrepancies. The classification indexes and ANOVA testing results both indicated that our method could achieve better results. These conclusions may be of much value in early diagnoses and clinical applications.
Thickness and optical constant determination of hydrogenated amorphous silicon thin film from transmittance spectra of ellipsometer
Authors: Liao Nai-Man  , Li Wei  , Jiang Ya-Dong  , Kuang Yue-Jun  , Qi Kang-Cheng  , Li Shi-Bin  , Wu Zhi-Ming  ,   (1)电子科技大学，电子薄膜与集成器件国家重点实验室，成都  610054; (2)电子科技大学，光电信息学院，成都  610054
Published: December 2020

To cope with the problem that the thickness and optical constants of thin film can not be measured accurately when deposited on a transparent substrate due to the incoherent reflected-light from the back-side of the substrate, a method is presented to determine the thickness and optical constants of hydrogenated amorphous silicon (a-Si:H) thin films deposited by plasma-enhanced chemical vapor deposition (PECVD) from the transmittance spectra of ellipsometer only. The influence of the substrate temperature (Ts) and the gas temperature (Tg) before glow discharge on the thickness and optical constants of a-Si:H thin films is analysed. The results show that the thickness of a-Si:H thin films determined by transmittance spectra agrees well with that measured by scanning electron microscopy (SEM). The optical constants of the films deduced from the transmittance spectra accord with the results obtained by other researchers. This method can be applied in deposition of amorphous or polycrystal thin films on transparent substrates.
Vector polarization mode switch mechanism of the vertical-cavity surface-emitting laser with anisotropic optical feedback injection
Authors: Zhong Dong-Zhou  , Cao Wen-Hua  , Wu Zheng-Mao  , Xia Guang-Qiong  ,   (1)五邑大学信息学院，江门  529020; (2)西南大学物理学院，重庆  400715
Published: December 2020

Vector polarization mode switch mechanism of the vertical-cavity surface-emitting laser with anisotropic optical injection is numerically investigated. The results are as follows:First, when the injection current is near the threshold current, the polarization state of the VCSEL output is determined by the power of each polarization mode of the optical feedback injection,which is controlled by the external parameter of the VCSEL and the polarizer. Second, the polarization state of the VCSEL output induced by anisotropic optical feedback injection under the controll of polarizer changes periodically. Third, the x^-polarization mode competes drastically with the y^_polarization mode when the power of the x^-polarization of the feedback injection is equivalent to that of the y^_polarization, which induces slight external disturbance of the laser to break the balance of two competing polarization modes. So, on this condition, the polarization state is sensitive to the external parameter change. At last，the y^_polarization mode obtains enough big gain when the injection current is much higher above the threshold current. At this time, the output of the VCSEL is in steady y^_polarization mode. In other words, the polarization state of the VCSEL output is now independent of other parameters.
Theoretical calculation of the partial cross section in He-H2(D2,T2) collisions
Authors: Shen Guang-Xian  , Wang Rong-Kai  , Linghu Rong-Feng  , Yang Xiang-Dong  ,   (1)贵州师范大学理学院,贵阳  550001; (2)贵州师范大学理学院,贵阳  550001；四川大学原子与分子物理研究所,成都  610065; (3)四川大学原子与分子物理研究所,成都  610065
Published: December 2020

Tang-Toennies potential model and close-coupling method were applied to the He-H2(D2,T2) system，and the vibrational and rotational excitation cross sections at different incidence energy have been calculated.By analyzing the differences of these partial wave cross sections, the change rules of the partial wave cross sections with increase of quantum number, and with change of reduced mass of symmetric isotopic substituted system have been obtained. Based on the calculation, influence on the cross sections exerted by the variations in the reduced mass of systems and in the relative incoming energy of incident atom is discussed.
Systematic investigation of shape-coexistence in Se,Kr,Sr and Zr isotopes with relativistic mean field theory
Authors: Sheng Zong-Qiang  , Guo Jian-You  ,   (1)安徽大学物理与材料科学学院，合肥  230039; (2)安徽理工大学数理系，淮南  232001
Published: December 2020

The even-even nuclei of Se, Kr, Sr and Zr isotopes are investigated systemically by the constrained relativistic mean field theory with the interactions NL3. The calculated binding energies of ground state for Se, Kr, Sr and Zr isotopes are described fairly well as compared with experiments. By examining the potential energy surfaces obtained by this microscopic approach, it can be found that the shape-coexistence phenomenon is very common in this region. The possible nuclei with shape-coexistence are pointed out systemically and the energy differences between the two minima in the potential energy surfaces for those nuclei are presented as well. In addition, by examining the potential energy surfaces and the microscopic neutron single particle spectra, N=70 are suggested to be a possible neutron magic number in this region.
Evolution from vibration to rotation of 102Ru nucleus discussed within microscopic theory
Authors: Shi Zhu-Yi  , Zhang Chun-Mei  , Tong Hong  , Zhao Xing-Zhi  , Ni Shao-Yong  ,   (1)贵州民族学院物理系,贵阳  550025; (2)西北第二民族学院基础部,银川  750021; (3)西北第二民族学院基础部,银川  750021；贵州民族学院物理系,贵阳  550025
Published: December 2020

Based on the microscopic sdIBM-2 approach and the single-particle energies from experiment, with the use of the most general Hamiltonian, the vibrational band and rotational band of 102Ru nucleus as well as its evolutional process are reproduced very well by two parameters of nucleon-nucleon effective interactions, respectively. Microscopic and phenomenological study identifies that: 1) the coexisting region of two excitation models are located in the interval between the state 8+1 and state 12+1 (which is an interval with Ex=2.50—4.00 MeV), the 8+1 state is a state predominant in the vibrational model, the 12+1 state is one predominant in the rotational model, while the state 10+1 is neutral relative to two models; 2) the 12+1 state is a medial state decoupled from the 14+1 state to the 10+1 state as well released photons; 3) the yrast states from the ground-state up to the 20+1 state are collective states, hereafter the first breaking up and aligning state may be a neutron two-particle-state in the intruder orbits h11/2; 4) this structure evolution is not very furious, but achieved softly by the boson structure constant changing unobviously in the coexisting region.
The structure and potential energy function of AlOH(CS，X1A′)
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，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 MP4/6-311G(3df,3pd) method, the equilibrium geometry of AlOH molecule has been calculated .The possible electronic state and the reasonable dissociation limit for the ground state of AlOH (CS，X1A′) molecule is determined based on atomic and molecular reaction statics. The analytic potential energy function of AlOH molecule was derived by many-body expansion theory.
The structure and potential energy function of SiOH and HSiO
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，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 B3P86/6-311++G** method, the equilibrium geometry of SiOH/HSiO (CS，X2A′)molecule has been calculated .The possible electronic state and the reasonable dissociation limit for the ground state of SiOH molecule is determined based on atomic and molecular reaction statics. The analytic potential energy function of SiOH molecule was derived by many-body expansion theory.
Studies on the high-lying vibrational energies and molecular dissociation energies for some electronic states of K2 molecule
Authors: Liu Yan  , Ren Wei-Yi  , Wang A-Shu  , Liu Song-Hong  ,   西华师范大学理论物理研究所，南充  637002
Published: December 2020

In view of the importance of the full vibrational spectrum and the molecular dissociation energies of K2 molecule to many studies and applications, this paper uses the SUN and REN's algebraic method (AM) which is based on perturbation theory and the algebraic energy method (AEM) based on the AM to study the vibrational spectroscopic constants, and the full vibrational spectra (Eυ) including the excited high-lying vibrational energies of electronic states X1Σ+g,a3Σ+u,0-g,B1Πu and 33Πg of K2 molecule, and obtain the accurate theoretical values of dissociation energies(De) of these states. The full vibrational spectra, especially the high-lying vibrational energies and dissociation energies, are difficult to determine experimentally, so this study can provides physical data for scientific research.
Control of vibrational excitation for the linear triatomic molecule by the Lie-algebra approach
Authors: Feng Hai-Ran  , Ding Shi-Liang  ,   (1)济宁学院物理系，济宁  273155; (2)山东大学物理与微电子学院，济南  250100
Published: December 2020

In this paper the control of vibrational excitation for the linear triatomic molecule has been studied. Selective vibrational excitation has been achieved successfully. Multiphoton excitation and the influence of the laser pulse shape on control have also been discussed.
Propagation dynamics of off-axis phase singularities
Authors: Liu Pu-Sheng  , Cheng Ke  , Lü Bai-Da  ,   四川大学激光物理与化学研究所，成都  610064
Published: December 2020

An analytical expression for the half-plane diffraction of off-axis phase singularity beams based on Gaussian intensity profile is derived, which enables us to study the propagation dynamics of off-axis phase singularities in detail. It is shown that the half-plane screen diffraction, off-axis displacement and propagation distance affect the propagation behavior and spatial distribution of phase singularities. By varying the off-axis displacement and propagation distance, the creation, shift and annihilation of phase singularities in the diffraction field may appear.
The interactions of a two-level atom with a coherent field of time-varying frequency: the two-photon transition
Authors: Li Zheng-Hong  , Yu Ming-Zhang  , Yang Ya-Ping  ,   同济大学物理系，上海  200092
Published: December 2020

The two-photon transition for a two-level atom interacting with a single-mold electromagnetic field has been investigated. The initial coherent states with time-varying frequency are considered. The effects of the frequency modulation in sinusoidal form on the atomic population inversion and the squeezing properties of the atom and field are studied. The frequency change can lead the collapse-revival period of population inversion to increase, the maximum value of the revival to decrease, and the squeezing effects of the field and atom are weakened.
Stimulated Raman scattering of YbVO4 crystal
Authors: Hu Da-Wei  , Wang Zheng-Ping  , Zhang Huai-Jin  , Xu Xin-Guang  , Wang Ji-Yang  , Shao Zong-Shu  ,   山东大学晶体材料国家重点实验室，济南  250100
Published: December 2020

With an ultra-cavity single-pass configuration, the stimulated Raman scattering (SRS) of a new crystal YbVO4 was investigated. When the pump source was a 532 nm pico-seconds laser, as many as three Stokes lines (558.47, 587.92 and 620.67 nm) and one anti-Stokes line (507.58 nm) were observed. The steady-state Raman gain coefficient for the first Stokes line was measured to be 17.8±0.2 cm/GW, and the total conversion efficiency reached 37%. For the first time, the SRS of YbVO4 crystal for 355 nm pump laser was realized. The first Stokes line (366.11 nm) was observed, and according to the pumping thresholds, the steady-state Raman gain coefficient was determined to be 29.0±0.3 cm/GW.
Design and optimization of photonic crystal coupling layer for bi-color quantum well infrared photodetectors
Authors: Wang Ke  , Zheng Wan-Hua  , Ren Gang  , Du Xiao-Yu  , Xing Ming-Xin  , Chen Liang-Hui  ,   中国科学院半导体研究所纳米光电子实验室,北京  100083
Published: December 2020

Finite difference time domain (FDTD) method is used for the simulation and analysis of electromagnetic field in the top coupling layer of GaAs/AlGaAs quantum well infrared photodetector (QWIP). Simulation results demonstrated the coupling efficiencies and distributions of electromagnetic (EM) field in a variety of 2D photonic crystal coupling layer structures. A photonic crystal structure for bi-color-QWIP is demonstrated with high coupling efficiency for two wavelengths.
The elastic wave propagation in two-dimensional phononic crystal at low frequencies and the anisotropy of effective velocity
Authors: Cai Li  , Han Xiao-Yun  , Wen Xi-Sen  ,   国防科技大学机电工程研究所,长沙  410073
Published: December 2020

The propagation of elastic waves in two-dimensional phononic crystal is investigated theoretically in the long-wavelength limit by the MST method. Exact analytical formulas for effective velocities of elastic waves are derived according to the behavior of the Mie scattering solution and the lattice sum in the long-wavelength limit. It has been found that the coupling effect between the two second-order components of the cylindrical scattered wave changes with the propagation orientation. Therefore whether the effective velocities of the propagating modes are anisotropic depends on whether the second-order components of the Mie scattering are indispensable.
Effect of a Planckian radiation field on population of bound-electrons
Authors: Wang Wei  , Zhang Jie  , Zhao Gang  ,   (1)首都师范大学物理系，北京  100037;中国科学院国家天文台，北京  100012; (2)中国科学院国家天文台，北京  100012; (3)中国科学院物理研究所光物理实验室，北京  100080
Published: December 2020

The basic atomic physical processes of laser beams interacting with a solid target is checked and the effects of a Planckian radiation field on the population of bound electrons are studied. The results illustrate that the radiation field, if it has a truly Planckian distribution, will influence on the physical processes in plasmas. For instance, it can ensure the distribution of the population on the different ionization stages under the LTE conditions even when the plasmas density is low enough that the collision rates do not dominate over radiative rates.
Diagnosis and investigation of the formation of low density and large sized clusters
Authors: Yang Ming  , Liu Jian-Sheng  , Cai Yi  , Wang Wen-Tao  , Wang Cheng  , Ni Guo-Quan  , Li Ru-Xin  , Xu Zhi-Zhan  ,   中国科学院上海光学精密机械研究所强场激光物理国家重点实验室，上海  201800
Published: December 2020

The laser-cluster interaction has been an important research field for decades, which would play an important role in understanding the laser-matter interaction. In order to generate satisfactory cluster sources, all factors that would affect the generation of the clusters should be understood. In this paper, linearly chirped spectral scattering is employed to study the size of the clusters during the process. And also, low density and large sized clusters is observed, which could be important clean targets in future experiments.
Integrated all fiber optical pulse generation system for laser fusion driver
Authors: Lin Hong-Huan  , Wang Jian-Jun  , Sui Zhan  , Li Ming-Zhong  , Chen Guang-Hui  , Ding Lei  , Tang Jun  , Deng Qing-Hua  , Luo Yi-Ming  , Dong Yi-Fang  , Li Feng  ,   (1)中电集团第23研究所，上海  200437; (2)中国工程物理研究院激光聚变研究中心，绵阳  621900; (3)中国科学技术大学物理系，合肥  230026
Published: December 2020

We demonstrate an integrated all fiber optical pulse generation system for laser fusion driver. CW laser signal generated from a single longitudinal fiber oscillator was modulated by phase modulator and amplitude modulator to form an optical pulse with shaped waveform and bandwidth of 0.1 nm. The pulse was amplified and split by fiber multiplexer to four pulses. Time delay of each pulse was controlled by synchronization unit and power of each pulse was adjusted by programmable variable optical attenuator. The four pulses were amplified and then transmitted through a 150 m fiber to the pre-amplify system. The fiber system can generate almost arbitrarily shaped optical pulse with duration of 0.2—20 ns, bandwidth of 0.1 nm and power of several nJ. As the front-end of the SG-Ⅲ prototype facility, it has successfully lunched about 2.6 million shots of pulses. The fiber system is compact and highly stable and reliable.
Improving parallel electrode method by sputtering atoms' angle distribution rule
Authors: Xie Guo-Feng  ,   湘潭大学材料与光电物理学院，湘潭  411105
Published: December 2020

In atomic vapor laser isotope separation (AVLIS) engineering, the parallel electrode method has the advantage of simple structure, but when the extraction voltage is high, the sputtering loss is very large and the collection ratio is very low. This paper calculates the angular distribution of sputtering atoms by Trim code. The results show that the angular distribution follows the cosine rule. The collection method is modified according to the rule, which makes the collection ratio very high.
Ionization of background gas by an intense relativistic electron beam
Authors: Song Fa-Lun  , Zhang Yong-Hui  , Xiang Fei  , Chang An-Bi  ,   中国工程物理研究院应用电子学研究所，绵阳  621900
Published: December 2020

In the paper, the interaction of an intense relativistic electron beam with the background gas in the high power microwave diode is studied. According to the experimental data, the plasma density generated by impact ionization have been calculated using the numerical methode and particle-in-cell code. The results show that the values of the plasma density produced by impact ionization obtained by the two calculating methods agree well. The ionized plasma densities are 4－12×109cm-3 at the pressures of 0.01 Pa—0.05 Pa. Even considering the two- and three-body recombination effects, the values of the plasma densities produced by impact ionization obtained by the numerical methode and particle-in-cell code still agree well. In addition, the results of PIC simulation show that there is a hump in the plasma density curve with the increasing of pressure. Different from the simple numerical calculation, in calculating the plasma densities, the experimental data are used. The results obtained by the two calculation methodes using the experimental data will be very useful for high power microwave diode and microwave devices.
Synthesis and welding of H-doped and N-doped carbon nanowires
Authors: Wang Zhen-Xia  , Pan Qiang-Yan  , Yong Zheng-Zhong  , Hu Jian-Gang  , Zhu Zhi-Yuan  ,   (1)中国科学院上海应用物理研究所，上海  201800; (2)中国科学院研究生院，北京  100049
Published: December 2020

A efficient and novel experimental method for synthesis and welding of amorphous carbon nanowires (ACNWs) by using double ion irradiations and heat-treatment is described. Experimental samples were characterized using high resolution transmission electron microscopy (HR-TEM). The results demonstrate that the proper combination of double ion irradiations and heat-treatment may make the multiwalled carbon nanotubes (MWCNTs) to become amorphous carbon nanowiro, thus enabling the welding of crossed ACNWs. In addition, the atomic evolution in carbon structural phase transformation is briefly discussed in connection with the current prevailing ideas.
The nonlinear elastic behavior of crystalline solids: An atomistic simulation study
Authors: Wen Yu-Hua  , Zhang Yang  , Zhu Zi-Zhong  ,   (1)兰州理工大学甘肃省有色金属新材料国家重点实验室，兰州  730050;厦门大学物理系，厦门大学理论物理与天体物理研究所，厦门  361005; (2)厦门大学物理系，厦门大学理论物理与天体物理研究所，厦门  361005
Published: December 2020

In this paper, we employ molecular static approach with quantum corrected Sutten-Chen many-body potential to study the elastic responses of nickel monocrystal subjected to uniaxial tensile and compressive loading, and consider three different loadings, i.e., the ［001］, ［011］ and ［111］ loding. The simulated results show that strong nonlinear effects are found in the elastic behavior of monocrystal under the ［011］ loading, while the lateral deformations are essentially isotropic under ［100］ and ［111］ loadings. The further discussions are focused on the dependence of the Young's moduli and Poisson's ratios on the applied strain, and a brief comparison with first-principles calculations is also presnted.
Influence of dispersive magnetic permeability on modulation instability in metamaterials
Authors: Dai Xiao-Yu  , Wen Shuang-Chun  , Xiang Yuan-Jiang  ,   湖南大学计算机与通信学院，长沙  410082
Published: December 2020

The influence of dispersive magnetic permeability on propagation of untrashort pulses in metamaterials is mainly in that it leads to the appearance of the pseudo-χ(5), self-steepening (SS) and second-order nonlinear dispersion terms in the propagation equations. In this paper, the role of dispersive magnetic permeability in modulation instability (MI) in metamaterials is identified based on the Drude model. It is found that in the anomalous dispersion regime, the pseudo-χ(5) nonlinear parameter, which is always negative, increases the MI frequency and growth rate, which is opposite to that in ordinary positive-index materials; the SS tends to suppress MI regardless of its sign, while the second-order nonlinear dispersion effect tends to stimulate MI in the positive-index region and suppress MI in the negative-index region. In the normal dispersion regime, in which MI cannot occur in the ordinary materials, MI can occur due to the role of the second-order nonlinear dispersion, suggesting a new way of generating solitons or ultrashort pulse trains in the normal dispersion regime.
The effect of the substituted transitional atom M on the magnetism of the intermetallic compounds YFe11M
Authors: Huang Zheng  , Chen Bo  , Ma Huan-Feng  , Zhang Xiu-Lan  , Gao Guo-Qiang  , Qiang Wei-Rong  , Sun Guang-Ai  ,   (1)西南交通大学理学院，成都  610031; (2)中国工程物理研究院核物理与化学研究所，绵阳  621900
Published: December 2020

Based on the density functional theory (DFT)，using full-potential linearized augmented plane wave and improved local orbital (APW+lo)，the structure and magnetism of the magnetic materials YFe11M (M=Ti，Si etc.) are analyzed and calculated. The possible positions of the substitutional atom M are analyzed. The effect of the substituted atom M on the magnetism of the intermetallic compounds YFe11M is discussed.
Study of conductive property for a N-VDMOS interface trap under X-ray radiation
Authors: Sun Guang-Ai  , Hu Gang-Yi  , Yang Mo-Hua  , Xu Shi-Liu  , Zhang Zheng-Fan  , Liu Yu-Kui  , He Kai-Quan  , Zhong Yi  ,   (1)电子科技大学微电子与固体电子学院，成都  610054; (2)电子科技大学微电子与固体电子学院，成都  610054;模拟集成电路国家重点实验室，重庆  400060; (3)模拟集成电路国家重点实验室，重庆  400060; (4)中国电子科技集团公司第二十四研究所，重庆  400060
Published: December 2020

An N-channel VDMOS I-V curve is measured after X-ray radiation under condition of different power dissipation. It is found that the property of new interface traps induced by X-ray radiation of self-annealing VDMOS sample does not conform to existing theory reasonably well. Based on measured data，we advance the viewpoint that the interface trap has current conductive property besides being charged up, and the conduction is assumed to be the generation or recombination current caused by new interface traps, which can not be simply identified quantitatively from the I-V curve.
Single electron pumping at higher frequency in a novel semiconductor-based quantum dot device
Authors: Li Ling  , Kaestner B  , Blumenthal M D  , Giblin S  , Janssen T J B M  , Pepper M  , Anderson D  , Jones G  , Ritchie D A  , Gao Jie  ,   (1)Cavendish Laboratory，University of Cambridge，Cambridge CB3 0HE，UK; (2)National Physical Laboratory，Hampton Road，Teddington TW11 0LW，UK; (3)National Physical Laboratory，Hampton Road，Teddington TW11 0LW，UK；Cavendish Laboratory，University of Cambridge，Cambridge CB3 0HE，UK; (4)Physikalisch-Technische Bundesanstalt，38100 Braunschweig，Germany; (5)四川大学物理科学与技术学院，成都  610064; (6)四川大学物理科学与技术学院，成都  610064；四川师范大学物理学院与固体物理研究所，成都  610066
Published: December 2020

The π-shift sinusoidal signals with different amplitudes applied directly to the two metallic finger gates on a shallow etched GaAs/AlGaAs quantum wire，tune unequally the two barriers of a static quantum dot induced by applying negative dc voltages on these two finger gates. Single electrons are transported through a periodically formed quantum dot without source-drain bias. Since single electron pumping in the novel semiconductor-based quantum dot device does not rely on Coulomb blockade of tunnelling，the device can not be limited to much lower frequency by the fixed tunneling time constant. Current plateaus due to single electron transport can be observed at 1.7K with frequencies up to 3GHz and a current level of 0.5nA. This novel device represents another possible path in the realization of a high current high accuracy quantum standard for electrical current，and also provides another means for high specd high accuracy transport of single electrons.
Study of AlGaN/GaN MOSHEMT device with Al2O3 insulating film
Authors: Feng Qian  , Hao Yue  , Yue Yuan-Zheng  ,   西安电子科技大学微电子研究所，西安  710071；宽禁带半导体材料与器件教育部重点实验室，西安  710071
Published: December 2020

On the basis of AlGaN/GaN HEMT，the AlGaN/GaN MOSHEMT device was fabricated with Al2O3 insulating film for the first time, which was deposited by ALD.The X-ray photoelectron spectroscopy measurements showed successful deposition of Al2O3 layer on the AlGaN/GaN film. The results of Schottky capacitance，I-V characteristics and DC transfer characteristics measurement showed that the interface state density between the AlGaN film and the Al2O3 insulating film was fairly low and the MOSHEMT device showed successful gate control of drain current up to VGS=+3V and achieved drain saturation current of 800mA/mm，which was much larger than that of the HEMT device. Furthermore，the gate leakage current of MOSHEMT is two orders lower in the reverse bias condition as compared with the Schottky gate structure，which increased the device breakdown voltage，while the leakage current was governed by the Fowler-Nordheim tunneling mechanism.
A new analytical model of breakdown voltage for the SD LDMOS
Authors: Li Qi  , Zhang Bo  , Li Zhao-Ji  ,   电子科技大学IC设计中心，成都  610054
Published: December 2020

In this paper，a novel analytical model for breakdown voltage of SD LDMOS is developed. Based on the 2-D Poisson's solution，the model gives the analytical solutions of the surface potential and electrical field distributions as functions of the structure parameters and drain bias；and the dependence of breakdown voltage on structure parameters is calculated. An effective way to attain the optimum high-voltage devices is also proposed. All analytical results were verified by simulation results obtained by MEDICI and previous experimental data，showing the validity of the present model. As a result of the modulation of the drift region and subtrate' field，the on-resistance is decreased and new electrical field peak are produced inside the drift region which improves the surface electrical field distribution and increases the breakdown voltage. The SD structure led to a significant improvement of breakdown voltage of about 26% and a reduction of on-resistance of about 33% compared to the conventional structure.
Retarded modes of lateral ferromagnetic/ferromagnetic superlattice
Authors: Liu Yan-Fen  , Liu Jing-Hui  , Jia Cheng  ,   (1)哈尔滨师范大学物理系 哈尔滨  150025; (2)哈尔滨师范大学物理系 哈尔滨  150025；齐齐哈尔大学物理系，齐齐哈尔  161006
Published: December 2020

In this paper，we calculated the retarded modes of semi-infinite lateral ferromagnetic/ ferromagnetic superlattice with the effective-medium theory. We took the Co/Ni system surface modes and bulk modes as the examples for the superlattice and found some interesting properties different from that of the lateral ferromagnetic/nonmagnetic superlattice. Lateral magnetic/magnetic superlattice have some complex retarded modes which are very common in the systems. Changing the ratio of the thicknesses of the ferromagnetic layers, the two branches of surface mode frequency and bulk mode frequency band can be adjusted consequently. This tailoring effect is related to the two ferromagnetic layers' saturation magnetization values, and it is quite pronounced when the two saturation magnetization values are quite different from each other. If the difference between the tow values is large，the tailoring effect of f1 is more obvious. When the saturation magnetization value of the second ferromangtic medium approaches to zero，this system will become the magnetic/nonmagnetic superlattice. If in Maxwell equation ε=0，the retarded modes will transit to the ferromangtic/ferromangnetic superlattice magnetostatic modes.
Preparation and emission properties of a sub-micrometer carbonate emission material
Authors: Wang Xiao-Xia  , Liao Xian-Heng  , Luo Ji-Run  , Zhao Qing-Lan  ,   中国科学院电子学研究所，北京  100080
Published: December 2020

Oxide cathodes have widely been used as electron emission source in vacuum electronic devices. Emission of an oxide cathode is dependent upon the ratio of the different ingredients of three kinds of alkaline earth carbonates on the cathodesurface and its microcopic shape. The synthesizing method plays a key role on the shape and ingredient of the carbonates. A new synthesis method，gas-liquid method，has been used to prepare the carbonates in this paper. The grains of the carbonates have filamental shape with sub-micrometer diameter. The testing results show that the cathode prepared with this sub-micrometer carbonate has large emission current density and long lifetime. The surface state and structure of the cathode are also analyzed with SEM in order to understand the mechanism of the enhanced emission current.
Transverse superresolution and axial extended focal depth realized by the tunable phase pupil filter
Authors: Yun Mao-Jin  , Wan Yong  , Kong Wei-Jin  , Wang Mei  , Liu Jun-Hai  , Liang Wei  ,   (1)济南大学光电材料研究所，济南  250002; (2)青岛大学物理科学学院，青岛  266071
Published: December 2020

In order to overcome the drawback of the conventional pupil filters and realize the tunable superresolution of the optical system, a new type of tunable pure phase filter composed of a half-wave plate located between two quarter-wave plates is presented in this paper, in which the half-wave plate is made of two zones. The simulation results show that with such a pupil filter the tunable transverse superresolution as well as the axial extended focal depth of the optical system can be realized by rotating any zone of the half-wave plate.