bluuebunny/crossref_metadata_2025 huggingface dataset:
The effect of Coulomb potential to the decoherence of the parabolic quantum dot qubit
Authors: Yin Ji-Wen  , Xiao Jing-Lin  , Yu Yi-Fu  , Wang Zi-Wu  ,   (1)内蒙古赤峰学院物理与电子信息工程系，赤峰  024000; (2)内蒙古民族大学物理与电子信息学院，通辽  028043
Published: December 2020

On the condition of electric-LO phonon strong coupling in parabolic quantum dot, we obtained the eigenenergy of the ground state and the first excited state, the eigenfuctions of the ground state and the first excited state by using variational method of Pekar type. This system of quantum dot may be employed as a two-level quantum system-qubit. The phonon spontaneous emission causes the decoherence of the qubit. We discussed the relatoion between the decoherence time and the Coulomb binding parameter，the couping strength, the confinement length, and the conefficient dispersion.
Ultra-broadband optical parametric amplification based on pre-chirp controlling
Authors: Song Xiao-Zhong  , Liu Hong-Jun  , Wang Yi-Shan  , Zhao Wei  ,   (1)瞬态光学与光子技术国家重点实验室，中国科学院西安光学精密机械研究所，西安  710119; (2)瞬态光学与光子技术国家重点实验室，中国科学院西安光学精密机械研究所，西安  710119;中国科学院研究生院，北京  100049
Published: December 2020

For optical parametric amplification with broadband pump coming from the second harmonic of an amplified Ti:sapphire laser syetem, a novel ultra-broad bandwidth phase-matching approach is investigated. The results show that an approximately 400nm phase-matching bandwidth can be obtained by using a 10nm pump bandwidth. Moreover, the phase-matching bandwidth can reach 600nm when the pump bandwidth attains 20nm. In order to obtain temporal overlap of phase-matched spectral components, a linear chirp in the pump requires a quadratic chirp in signal. The photonic crystal fiber with a zero-dispersion wavelength of 800nm generates a supercontinuum with a quadratic chirp. The broadband pump pulse is stretched to a linear chirped pulse by a prism pairs. Calculations concerning the appropriate length of fiber and prism sequence to be inserted in optical path for the pre-chirp controlling were performed, the results of which provide a theoretical basis for implementing the ultra-broadband optical parametric amplification.
The analysis of dynamic structure of silicon content in blast furnace hot metal
Authors: Zhao Min  , Liu Xiang-Guan  , Gao Chuan-Hou  ,   浙江大学数学系，系统优化技术研究所，杭州  310027
Published: December 2020

With Si time series of No.7 blast furnace (BF) at Han Iron and Steel Group Co. as sample space, the stationarity of Si time series is tested based on the number of reversed order. A statistical measure of dynamic closeness between two orbits is defined using correlation integral. Divide the Si series into equal-length windows, according to the calculation of the characterization between these windows, the dynamic abrupt changes in BF ironmaking process are detected. Finally the novel DVV (delay vector variance) method is used to examine the predictability of Si time series during the dynamic evolution.
The collision of one keyed Hash function based on chaotic map and analysis
Authors: Wang Ji-Zhi  , Wang Mei-Qin  , Wang Ying-Long  ,   (1)山东大学密码技术与信息安全教育部重点实验室，济南  250100; (2)山东省计算中心，济南  250014
Published: December 2020

The collision of a keyed hash function based on chaotic map is pointed out. Its principle is analyzed in theory. The definition of the nonsingularity is presented based on analyzing digital discrete chaotic sequence. The necessary and sufficient conditions for the nonsingularity is deduced. The period of digital discrete chaotic sequence with variable parameter is discussed. The result shows that the singulartiy of chaotic sequence leads to the collision of the hash function. So the digital method of chaotic map must be chosen carefully to ensure the nonsingularity of chaotic sequence.
Parameter estimation for chaotic systems based on hybrid differential evolution algorithm
Authors: Wang Jun-Yan  , Huang De-Xian  ,   清华大学自动化系，北京  100084
Published: December 2020

Parameter estimation for chaotic systems is one of the important issues in chaotic control and synchronization. Through establishing an appropriate fitness function, the parameter estimation problem is formulated as a multi-dimensional functional optimization problem, which can be solved by using hybrid differential evolution (HDE) algorithm. A numerical simulation on the Lorenz system is conducted and the results demonstrate the effectiveness and robustness of the proposed algorithm, which is shown to be an effective method of parameter estimation for chaotic systems.
Control of chaos in a delayed feedback semiconductor laser via dual-wedges
Authors: Yan Sen-Lin  ,   南京晓庄学院物理系，南京  210017
Published: December 2020

A method of controlling chaos is presented via dual-wedges in a delayed feedback semiconductor laser. The physical model of the laser dynamics is set up under the condition of the dual-wedges control. The optical-length of the transmission of feedback light in the external cavity can be governed by modulating the dual-wedges while the delay time and feedback intensity of the feedback light are varied. The dual-parameter chaos-control of the delay time and feedback intensity can be physically realized. The chaotic laser can be controlled in periodic states and its mean pulse power increased, as shown by numerical simulations.
A new analysis method of multi-cladding photonic crystal fibers
Authors: Wei Dong-Bin  , Zhou Gui-Yao  , Zhao Xing-Tao  , Yuan Jin-Hui  , Meng Jia  , Wang Hai-Yun  , Hou Lan-Tian  ,   (1)燕山大学红外光纤与传感研究所，秦皇岛  066004; (2)燕山大学红外光纤与传感研究所，秦皇岛  066004；燕山大学亚稳材料制备技术与科学重点实验室，秦皇岛  066004
Published: December 2020

The conventional effective index method can only simulate the photonic crystal fibers with single cladding structure. To solve the problem，an improved effective index method is proposed in this paper. It calculates the propagation properties of multi-cladding photonic crystal fibers. The indices and total dispersions of the guided modes of three-cladding photonic crystal fibers are investigated by this method. The results agree closely with those of the multipole method. Improved effective index method not only extends the application of conventional effective index method，but also provides theoretical support for analyzing and designing multi-cladding photonic crystal fibers with different propagation characteristics.
The amplitude and phase measurements of femtosecond pulses using fringe-free SPIDER
Authors: Lei Liang  , Wen Jin-Hui  , Jiao Zhong-Xing  , Lai Tian-Shu  , Lin Wei-Zhu  ,   中山大学光电材料与技术国家重点实验室，广州  510275
Published: December 2020

A developed method of fringe free spectral phase interferometry reconstruction (FF-SPIDER) for femtosecond pulse measurement is demonstrated with theoretical simulation and experimental measurements. FF-SPIDER overcomes the disadvantages of the traditional SPIDER in which the time delay measured pulse replica results in fringes in the interference spectrum and complicates the spectral phase reconstruction. The measurement results show that FF-SPIDER reconstructs the amplitude and phase of the measured pulses with higher efficiency, higher accurate and lower requirements on measurement apparatus.
First principles study of In-N codoped ZnO
Authors: Chen Kun  , Fan Guang-Han  , Zhang Yong  , Ding Shao-Feng  ,   华南师范大学光电子材料与技术研究所，广州  510631
Published: December 2020

The electronic structure of pure N-doped and In-N codoped wurtzite ZnO has been calculated by using first-principles ultra-soft pseudo-potential approach of the plane wave based upon the density functional theory，and the structure change，bandstructure，density of states，difference charge density and the influence of In-N codoped wurtzite ZnO by H atom were studied. The calculation results revealed that N-doped wurtzite ZnO caused formation of deep N acceptor levels in the band gap and the carriers (hole) were localized near the top of the valence band. But the codoping calculation revealed that the acceptor level shifted toward the lower-energy region and shallow acceptor level were fomed，which was broadened and showed delocalizing characters, owing to which the concentration of impurities and the stability of the system were enhanced. Our conclusions accord with the results of experiments, which confirms the fact that In-N codoping in wurtzite ZnO helps the formation of p-type ZnO. In addition, it was also pointed out that the presence of H atom reduces the efficiency of doping markelly，which should be avoided as much as possible.
Analysis of structure parameters and current conduction mechanisms of AlGaN/GaN Schottky contacts
Authors: Wang Xin-Juan  , Zhang Jin-Feng  , Zhang Jin-Cheng  , Hao Yue  ,   西安电子科技大学，宽禁带半导体技术重点实验室，西安  710071
Published: December 2020

An investigation on the current conduction mechanisms of AlGaN/GaN Schottky contacts is presented in this paper. The ideality factor and the barrier height of Schottky contact on AlGaN/GaN heterostructure are calculated by I-V measurement in a wide temperature range. By subtraction of generation-recombination, tunneling and leakage currents from the total current, the “pure" Schottky barrier height can be evaluated with higher physical relevance. After analyzing the variational rules of Schottky contact characteristics on AlGaN/GaN heterostructure at 300—550K, it is concluded that surface leakage current plays an insignificant role in producing the gate leakage current of AlGaN/GaN HEMT.
The study of ZnO varistor doped with ferromagnetic manganese oxide
Authors: Yang Xin-Sheng  , Zhao Yong  ,   材料先进技术教育部重点实验室和超导研究开发中心，西南交通大学，成都  610031
Published: December 2020

ZnO varistor doped with ferromagnetic manganese oxide (La07Sr03MnO3) was prepared by conventional electric ceramic technique. There are secondary phases, La07Sr03MnO3 and LaMnO3, existing at the grain boundaries. The content of insulating phase of LaMnO3 obviously affects the electrical properties of the samples. The samples still remained ferromagnetism after doping. Applied magnetic filed could change the electrical property. The resistance increased when magnetic field was applied, showing a positive magnetoresistance (PMR) phenomenon. The existence of PMR is due to the broadening of barrier at the grain boundaries caused by the magnetic field.
Optical property of modulated n-doped ZnSe/BeTe type-Ⅱ quantum wells
Authors: Ji Zi-Wu  , Mino Hirofumi  , Kojima Eiji  , Akimoto Ryoichi  , Takeyama Shojiro  ,   (1)产业技术综合研究所超高速光学器件实验室，日本  305-8568; (2)东京大学物性研究所,日本  277-8581; (3)千叶大学自然科学研究科，日本  263-8522
Published: December 2020

We report the optical properties of the modulated n-doped ZnSe/BeTe/ZnSe type-Ⅱ quantum wells. The reflection spectra have shown typical negatively charged exciton features only in a doped sample. The luminescence spectra and the polarization anisotropy depend strikingly on both the n-doping into the barrier layers and an applied external electric field perpendicular to the layer. These are explained by screening of the built-in electric field with n-doping and Stark effects due to the applied electric field. The electron density as well as the mass was determined in high magnetic field (up to 160 T) cyclotron-resonance measurements. It was found that the observed indirect PL transition occurs via the charged excitons in a type-II quantum configuration.
Steered molecular dynamics investigation of force-induced detachment of adsorbed single polymer chains
Authors: Wang Yu  , Zhang Lin-Xi  ,   温州大学物理系，温州  325027
Published: December 2020

The dynamics of the detachment of single polyethylene (PE) chain from a strongly adsorbing surface in vacuum is investigated by steered molecular dynamics method. When the chain is pulled from the monomer of N/3 (here N is the chain length), there are two force plateaus for the curve of the average force 〈f〉 probed by the ideal spring as a function of pulling distance Z，which agrees well with the experimental results. There are four different stages during the detachment of single polyethylene (PE) chains. As the chains are pulled in an inclined direction from one end, there exist always a linear relationship for average force probed by the ideal spring vs inclination angle θ for θ>20 degrees Furthermore, the slope of the line increases with the pulling velocity. However, for θ<20 degrees, the average force probed by the ideal spring tends to a fixed value of 780pN.
Some new exact Jacobian elliptic function solutions of three kinds of nonlinear evolution equations
Authors: Wu Hai-Yan  , Zhang Liang  , Tan Yan-Ke  , Zhou Xiao-Tao  ,   解放军理工大学气象学院,南京  211101
Published: December 2020

By using the modified mapping method, we find some new exact solutions of the nonlinear Klein-Gordon equation, mKdV equation and the generalized Boussinesq equation. The solutions obtained in this paper include Jacobian elliptic function solutions, combined Jacobian elliptic function solutions, soliton-like solutions and triangular function solutions.
Excitement and optimality properties of small-world biological neural networks with updated weights
Authors: Zheng Hong-Yu  , Luo Xiao-Shu  , Wu Lei  ,   广西师范大学物理与电子工程学院，桂林  541004
Published: December 2020

As the biological neural networks have small-world property and updating connection weights with time, we accordingly propose a new model of small-world biological neural networks based on biophysical Hodgkin-Huxley(H-H)neurons with updated weights. Then we study the statistical properties of excitement of this model and the updating of weights. The results show that, for networks with the same structure and parameters and external stimulation, there exists an optimal learning rate ralue b* which makes the excitement strength of biological neural networks strongest.
Study on high-temperature spectra of the asymptotic asymmetric-top molecule H122C16O
Authors: Song Xiao-Shu  , Linghu Rong-Feng  , Lü Bing  , Cheng Xin-Lu  , Yang Xiang-Dong  ,   (1)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; (2)四川大学原子与分子物理研究所，成都  610065
Published: December 2020

The line intensities of 100000-000000 transition of asymptotic asymmetric-top molecule H122C16O at several temperatures were calculated by directly calculating the partition functions and regarding the rotationless transition dipole moment squared as a constant. Results showed that the calculated line intensity data at 500 and 3000K are in excellent agreement with the data in HITRAN database，which provide a strong support for the calculations of partition function and line intensity at high temperature. Thereby，the line intensities and spectral simulations of 100000-000000 transition band at the higher temperature 4000 and 5000K were presented. The results are of significance for studying the high-temperature molecular spectrum by experimental measurement and theoretical calculation.
Laser parameter optimization and experimental study of end-pumped continuous wave Tm，Ho∶YLF lasers
Authors: Zhang Xin-Lu  , Wang Yue-Zhu  , Li Li  , Cui Jin-Hui  , Ju You-Lun  ,   (1)哈尔滨工程大学理学院，哈尔滨  150001; (2)哈尔滨工业大学光电技术研究所可调谐激光国家重点实验室，哈尔滨  150001
Published: December 2020

The output performance of a laser diode end-pumped continuous wave Tm，Ho∶YLF laser is studied and the laser parameters are optimized. Based the quasi-three-level rate equations，the relation formulus between the output power and the input power is deduced with consideration of the energy transfer up-conversion. The laser parameters such as the concentration of doped ions，the crystal length，the pump-to-mode size ratio and the transmittance of output coupler are optimized by numerical analysis. The output power as a function of pump power is obtained in experiment. Comparison of experimental and theoretical results shows that the theoretical results are valid.
Electrically tunable negative permeability metamaterials based on electrorheological fluids
Authors: Wang Lian-Sheng  , Luo Chun-Rong  , Huang Yong  , Zhao Xiao-Peng  ,   西北工业大学电流变技术研究所，西安  710072
Published: December 2020

We experimentally studied the effects of certain factors, such as the ways of loading of electrodes, the concentration of ER fluids, the type of ER fluids and intensity of applied electric fields, on the resonant frequency of split-resonant ring array infiltrated in ER fluids. The experimental results show that the way of loading of electrodes has important effects on the magnetic resonance of SRR array. The resonant frequency of SRR array shows a red-shift when the ER fluid is infiltrated, the maximum shift of about 130MHz was obtained through the adjustment of the applied electric-field. Numerical simulation demonstrates that the permeability of SRR array is negative near the resonant frequency, and the frequency range of negative permeability can be dynamically tuned by the applied electric-field.
The construction and application of the many-body potential for the Fe-Cr-V-Ni-Si-C system multi-component alloy
Authors: Liu Yan-Xia  , Wang Xun  , Ma Yong-Qing  , Zhang Cheng-Hua  ,   (1)大连海事大学机电与材料工程学院,大连  116026; (2)辽宁大学物理系,沈阳  110036
Published: December 2020

The interatomic potential function for the Fe-Cr-V-Ni-Si-C system multi-component alloys was constructed by fitting to the data of this alloy system via quantum chemistry ab initio calculation , first-principlespseudopotentials calculation and least squares method. The stability of the austenite matrixs of Fe-Cr-V-Ni-Si-C system alloys was examined by the acquired interatomic potential functions. The effect of Ni element on the stability of the alloy matrix was studied. The results of calculation show that the stability of austenite matrix with nickel content in the range of 1.02—2.03wt% increases with the increase of nickel content. When the nickel content in the alloys increases to 2.88 wt%, the austenite matrix energy increases and the stability of the austenite matrix decreases accordingly. The austenite matrix energy of N5—N8 alloy is lower than the energy of its martensite phase. Therefore, the microstructure of N5—N8 alloy tends to be of austenite-type. Analysis by XRD indicates that the matrix of N5—N8 alloy is mainly the austenite phase, complemented by martensite. The calculation results agree with the results of XRD.
Optical stopping effect of impurity-doping As2S8 glass waveguide
Authors: Du Li-Ping  , Chen Bao-Xue  , Sun Bei  , Chen Zhi  , Zou Lin-Er  , Hiromi Hamanaka  , Mamoru Iso  ,   (1)南昌大学物理系，南昌  330031; (2)日本东京农工大学 工学院应用化学系，东京  184-8588; (3)日本法政大学 工学院物质化学系,东京  184-8584; (4)上海理工大学 光电学院,上海  200093
Published: December 2020

The optical stopping effect in undopeel and low concentration Sn- and P-doped As2S8 amorphous thin films is studied experimentally. The optical stopping response curve, experimental data of room temperature deexcitation and spectral testing data of the samples are provided. The results show that, the Sn-doped sample can significantly improve the ms range response in the fast-recovery process, and has the effect in decreasing the residual propagation loss. But in P-doped sample, the effects are contrary to that in the Sn-doped sample. Based on the experimental results, some analysis and discussions are presented.
Reflection and refraction on the fluid-solid interface of acoustic field excited by a concave phased array
Authors: Zhang Bi-Xing  , Wang Wen-Long  ,   中国科学院声学研究所,北京  100080
Published: December 2020

The reflection and refraction on the fluid-solid interface of the acoustic wave excited by a concave phased array are studied in this paper. The analytical presentations of the refraction and reflection fields of the focused acoustical wave on the fluid-solid interface are obtained for the first times by the ray approximation method. The refraction fields in the solid are analyzed and discussed. The ultrasonic phased fields of the refraction compressional and shear waves in the solid are numerical simulated and investigated by the analytical presentations. It is found that the compressional and shear waves are better focused in the solid with a cylindrical fluid-solid interface than in that with a planar fluid-solid interface.
The DEM simulation for two-dimension granular system with point defects
Authors: Yi Chen-Hong  , Mu Qing-Sun  , Miao Tian-De  ,   (1)兰州大学土木工程与力学学院力学系，兰州  730000; (2)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

In this article, the discrete element method is used to research the force distribution of two-dimensional granular system under the condition of isotropic compression and pure shear. The simulation results are compared with the experimental results under the same conditions. Then we simulate the force distribution of two-dimensional granular system with point defects under the condition of isotropic compression and pure shear and compare the results with the results without point defects. The affects of point defects to granular system are found.
Investigation of interfacial structure and property of CoFe/TiZr multilayers by polarized neutron reflectometry
Authors: Huang Chao-Qiang  , Chen Bo  , Li Xin-Xi  , V. G. Syromyatnikov  , N. K. Pleshanov  ,   (1)俄罗斯科学院圣彼得堡核物理研究所，卡特金娜  188300; (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

Polarized neutron reflectivity has been measured for the CoFe/TiZr alloy multilayers. The results show that: (a) The reflectivity behavior of the sample with un-equal-thickness bilayer (type B) is better than that of the sample with equal-thickness bilayer (type A). The former performs better in producing neutron guide. (b) The best annealing temperature is about 250℃ for the sample of type A, however, the structures of both type A and type B samples change apparently after 350℃ annealing. (c) Different from the type B sample, the first Bragg peak position for the type A sample moves along Q axis， indicating that the period of the multilayer varies in a way of increase-decrease-increase with the increase of annealing temperature.
Self-compression and splitting of laser pulse in plasmas
Authors: Luan Shi-Xia  , Zhang Qiu-Ju  , Wu Hui-Chun  , Sheng Zheng-Ming  ,   (1)山东师范大学物理与电子科学学院，济南  250014; (2)中国科学院物理研究所光物理开放实验室，北京  100080
Published: December 2020

We study the self-compression and splitting of a circularly polarized laser pulse propagating in plasmas with density window from 1/4 critical to slightly below critical density by solving the nonlinear Schrdinger equation numerically. It is demonstrated by the numerical calculation that the effective self-compression of laser pulse can be achieved in even shorter distance by increasing both the background plasma density and intensity of the laser pulse, or decreasing the width of pulse. The full-width at half maximum of the compressed pulse can reach 1/35 of the initial one's or even smaller. It has been found that this kind of self-compression occurs in the process of formation of a high-order soliton when a laser pulse propagates in a plasma, so that we can obtain greats compression ratio than in thin plasmas. We also obtained the splitting of a high-order soliton formed after self-compression of a laser pulse propagating in plasmas from the result of the numerical calculation in this situation. The phenomenon of self-compression and splitting is also observed by using one-dimensional particle-in-cell simulations and the result was consistent with the numerical calculation.
Bonding configurations and photoluminescence of amorphous Si nanoparticles in SiNx films
Authors: Yu Wei  , Li Ya-Chao  , Ding Wen-Ge  , Zhang Jiang-Yong  , Yang Yan-Bin  , Fu Guang-Sheng  ,   河北大学物理科学与技术学院，保定  071002
Published: December 2020

The Si-in-SiNx:H films were prepared by helicon wave plasma chemical vapor deposition technique with active gas N2/SiH4/H2, and the tuning photoluminescence of the films from red to blue-green is achieved by changing the N2 flow rate. The analysis of Fourier transform infrared spectroscopy and ultraviolet-visible absorption demonstrate that the deposited films have higher hydrogen contents. Increasing of N2 flow rate makes the hydrogen bonding configurations change and the size of amorphous silicon particles decrease, to which corresponds the increase of band gap and also the decrease of the microstructure order. The tuning photoluminescence is mainly related to the quantum confinement of amorphous silicon particles. The broadening of the spectral widths of main photoluminescence and the enhancement of their intensities are obtained for the films deposited with increasing N2 flow rates.
Density functional study on the structural and electronic properties of fullerene-barbituric acid and its dimmer
Authors: Jiang Yan-Ling  , Fu Shi-You  , Deng Kai-Ming  , Tang Chun-Mei  , Tan Wei-Shi  , Huang De-Cai  , Liu Yu-Zhen  , Wu Hai-Ping  ,   (1)哈尔滨工业大学威海分校，威海  264209；南京理工大学应用物理系，南京  210094; (2)南京理工大学应用物理系，南京  210094; (3)中国药科大学物理教研室，南京  210009；南京理工大学应用物理系，南京  210094
Published: December 2020

Geometric and electronic properties of fullerene-barbituric acid and its dimmer have been studied using density functional theory (DFT) at BLYP level with DNP basis sets. The calculation results indicate that the only one stable geometry of the fullerene-barbituric acid is that with ［6,6］ close-bond structure, and the effects of the barbituric acid on the cage structure is mainly in the local region neighboring the barbituric acid. Among the three isomers of the fullerene-barbituric acid dimmers, one can come to the conclusion both from the energy gap and from relative energy that the ［6,6］—［6,6］ structure is the most stable one. With respect to the electronic structures, the donor-acceptor system corresponds to C60 fullerene-barbituric acid, ie. electron transfers from the fullerene cage to the barbituric acid. The frontier orbitals and spin population show that C60 fullerene-barbituric acid has similar electromagnetic properties of C60, but its stability is reduced, so that the addition reaction would easily take place to form its dimmer. For the C60 fullerene-barbituric acid dimmer, the Mulliken analysis shows there are 0104e and 0106e charge transfers to the four carbons from their neighboring carbons, and the farther the atoms is, the less charge it loses. Compared with those of the C60 fullerene-barbituric acid, the energy gap is changed from 152eV to 1.45eV, while the distribution of highest occupied molecular orbital (HOMO) is little changed but that of lowest unoccupied molecular orbital (LUMO) is changed a lot.
Influence of substrate temperature on the structure and photoluminescence of Mg0.05Zn0.95O thin films grown by pulsed laser deposition
Authors: Wu Xiao-Li  , Chen Chang-Le  , Han Li-An  , Luo Bing-Cheng  , Gao Guo-Mian  , Zhu Jian-Hua  ,   西北工业大学凝聚态结构与性质陕西省重点实验室，西安  710072
Published: December 2020

Highly c-axis oriented Mg0.05Zn0.95O thin films were fabricated on Si(111) substrates at different temperature by pulsed laser deposition. The influence of the substrate temperature on the structure and luminescent properties of Mg0.05Zn0.95O thin films were studied by XRD and photoluminescence (PL) spectra and the relationship between the crystalline quality and PL properties of thin films was discussed. The results indicate that the Mg0.05Zn0.95O thin films grown at substrate temperature of 450℃ show good c-axis orientation and strong PL peaks. Different PL spectra are acquired at room temperature using xenon lamps as excitation light sources，with excitation wavelengths of 240, 300 and 325nm, respectively. The UV peaks and violet peaks were found to originate from free excition radiation recombination and the PL intensity was related to crystalline quality, and the blue-green peaks may be related to the oxygen vacancies. We also discuss the physical mechanism throngh which the substrate temperature affects the red shift and blue shift of UV PL peaks.
Effect of the spectral function of quasiparticle on minimal conductivity of graphene
Authors: Luo Tao  , Zhu Wei  , Shi Qin-Wei  , Wang Xiao-Ping  ,   中国科学技术大学合肥微尺度物质科学国家实验室，合肥  230026
Published: December 2020

Under effective-mass approximation, the Kubo formula is used to calculate the minimal conductivity of graphene. It is found that the minimal conductivity depends on the spectral function of quasiparticle. If the distribution of the spectral function is taken to be Lorentz distribution, the minimal conductivity is 4e2/πh. If the distribution of the spectral function satisfies Gaussian distribution, however, the minimal conductivity is 2e2/h.
A novel element of frequency selective surface for radome
Authors: Li Xiao-Qiu  , Gao Jin-Song  , Zhao Jing-Li  , Sun Lian-Chun  ,   (1)中国科学院长春光学精密机械与物理研究所,长春  130033; (2)中国科学院研究生院，北京  100049
Published: December 2020

Based on the Y element, a novel element for the Frequency selective surface (FSS) is presented in this paper. The transmission characteristics of Y element FSS and the novel element FSS is calculated using Galerkin's method in the spectral domain, and the optimum parameters of the FSS is obtained. The corresponding equivalent FSS sample plate was fabricated. It's transmission characteristics were measured by microwave network analyzer at 8—12GHz. The agreement between the calculated and measured values was good. The results show that, the novel element FSS has excellent transmission characteristic at large-angle incidence, the transmission coefficient is -052dB at TE 66° incidence. From 0° to 66° TE incidence, the drift of the resonant frequency is 200MHz. Meanwhile the transmission coefficient of Y element FSS is -082dB at TE 66° incidence, and from 0° to 66° TE incidence, the drift of the resonant frequency is 400MHz. Therefore, the novel element FSS is more suitable than Y element FSS for the application in large-angle incidence curved streamlined radome.
Investigation of filling factor in In0.53Ga0.47As/In0.52Al0.48As quantum wells with two occupied subbands
Authors: Shang Li-Yan  , Lin Tie  , Zhou Wen-Zheng  , Guo Shao-Ling  , Li Dong-Lin  , Gao Hong-Ling  , Cui Li-Jie  , Zeng Yi-Ping  , Chu Jun-Hao  ,   (1)中国科学院半导体研究所，北京  100083; (2)中国科学院上海技术物理研究所红外物理国家重点实验室，上海  200083; (3)中国科学院上海技术物理研究所红外物理国家重点实验室，上海  200083；广西大学物理科学与工程技术学院，南宁  530004; (4)中国科学院上海技术物理研究所红外物理国家重点实验室，上海  200083；华东师范大学ECNU-SITP成像信息联合实验室，上海  200062
Published: December 2020

The magnetic field dependence of filling factors has been investigated on InP based In053Ga047As/In052Al048As quantum well samples with two occupied subbands by means of magnetotransport measurements at the temperature of 15K in a magnetic field range of 0 to 13T. Under the condiction that Laundau-level broadening is larger than the spin splitting of each subband, filling factors are even when the splitting energy of two subbands is an integer multiple of the cyclotron energy, i.e.ΔE21=kωc. If the splitting energy of two subbands is half of an odd interger multiple of the cyclotron erergy, i.e.ΔE21=(2k+1)ωc/2, the filling factor is odd.
Study of enhanced transmission of terahertz radiation through subwavelength fractals structures
Authors: Meng Tian-Hua  , Zhao Guo-Zhong  , Zhang Cun-Lin  ,   (1)首都师范大学物理系，北京  100037; (2)首都师范大学物理系，北京  100037；大同大学物电学院，大同  037009
Published: December 2020

The enhanced transmission of terahertzs radiation through the metal subwavelength fractal structures is studied by means of the terahertz time domain spectroscopy (THz-TDS). In view of experiment and theory, the physical mechanism of enhanced transmission of THz wave through each level of fractal lines on the copper film is studied. It is found that THz transmission enhancement in low frequency region mainly resulted from the electron resonance in low level lines, and that in high frequecy region mainly resulted from the electron resonance in high level lines. Thus the transmission enhancement can be attributed to the electron resonant radiation in the fractal structure, namely,the localized resonance efficiency of the frqctal structure.
Carrier spin relaxation in (Ga,Mn)As at room temperature
Authors: Liu Xiao-Dong  , Wang Wei-Zhu  , Gao Rui-Xin  , Zhao Jian-Hua  , Wen Jin-Hui  , Lin Wei-Zhu  , Lai Tian-Shu  ,   (1)中国科学院半导体研究所半导体超晶格国家重点实验室,北京  100083; (2)中山大学物理系，光电材料与技术国家重点实验室,广州  510275
Published: December 2020

In this paper, the excitation energy density dependence of carrier spin relaxation is studied at room temperature for the as-grown and annealed (Ga,Mn)As samples using femtosecond time-resolved pump-probe Kerr spectroscopy. It is found that spin relaxation lifetime of electrons lengthens with increasing excitation energy density for both samples, and the annealed (Ga,Mn)As has shorter carrier recombination and electron spin relaxation lifetimes as well as larger Kerr rotation angle than the as-grown (Ga,Mn)As under the same excitation condition, which shows that DP mechanism is dominant in the spin relaxation process for (Ga,Mn)As at room temperature. The enhanced ultrafast Kerr effect in the annealed (Ga,Mn)As shows the potential application of the annealed (Ga,Mn)As in ultrafast all-optical spin switches, and also provides a further evidence for the p-d exchange mechanism of the ferromagnetic origin of (Ga,Mn)As.
Microstructure, electrical and optical properties of Cd-doped CdTe thin films deposited by close-spaced-sublimation
Authors: Li Qian  , Zheng Yu-Feng  , Zhou Xiang-Ling  , Sun Yan-Fei  , Jian Ji-Kang  ,   (1)新疆大学物理科学与技术学院,乌鲁木齐  830046; (2)新疆喀什师范学院物理系,喀什  844000
Published: December 2020

Cd-doped CdTe polycrystalline films were deposited on ITO/glass substrates by close-spaced-sublimation (CSS)method. The microstructural, morphological, electrical and optical properties of the films were characterized by X-ray diffraction, scanning electron microscopy, Hall effect, and optical absorption. It is found that the crystallinity is improved, the electrical resistivity drops 4—5 orders of magnitude and the conductivity changes from p-type to n-type when pure CdTe film is doped with a proper amount of Cd. There is no obvious influence on the optical band gaps of the films by the doping of Cd.
Study on ultraviolet emission mechanism of micro-nano multi-scale ZnO structures
Authors: Wu Chun-Xia  , Zhou Ming  , Feng Cheng-Cheng  , Yuan Run  , Li Gang  , Ma Wei-Wei  , Cai Lan  ,   江苏大学光子制造科学中心,镇江  212013
Published: December 2020

The micro-nano multi-scale ZnO structure was synthesized by the vapor phase transport process onto Si (100) substrate. A typical scanning electron microscope (SEM) image of the sample clearly showed the surface has the complex structure of hexagonal micro and nano- rods. Photoluminescence (PL) spectra at room temperature showed an intense near-band-gap ultraviolet (UV) emission peak but no deep level emission related to impurities or defects, indicating that the sample has good optical quality. The temperature (83—307K) dependence of the PL spectra showed that the room-temperature UV emission resulted from two optical transitions, one related to the ZnO free exciton and the other related to the free-to-bound (FB) transition of the free cawier with the binding energy of about 124.6meV.
Study on the influence of the coupling hole on RF cavtiy
Authors: Liao Xu  , Ren Xue-Zao  , Zhou Zi-Gang  ,   西南科技大学理学院，绵阳  621010
Published: December 2020

The RF field in the RF cavity can be expressed by the modes of the cavity. And the characters of the cavity is determined by such modes as the frequency and field. In the paper，an actual cavity is divided into two parts: the normal part (such as a normal cylindrical cavity) and the abnormal part (including a coupling hole). According to Maxwell theory，there exists a coupling equation between the modes of normal part and the modes of the cavity. So the influence of the coupling hole can be studied. Utilizing the method，an L-band cylindrical cavity with a coupling hole is studied，the calculated frequency of the working mode is very close to the simulated value.
The ground state solutions of two-component Bose-Einstein condensates in Bessel optical lattices
Authors: Chen Hai-Jun  , Xue Ju-Kui  ,   西北师范大学物理与电子工程学院，兰州  730070
Published: December 2020

The ground state solutions of two-component Bose-Einstein condensates (BECs) in Bessel optical lattices (BLs) are studied by means of the balance condition between BLs strength and inter-atomic interactions. We consider a quasi-two-dimensional (2D) BECs system，strongly confined in longitudinal direction and weakly trapped in the radial direction in the transverse plane，which obeys 2D Gross-Pitaevskii equation (GPE) derived from its 3D counterpart. Analytically we obtained the atom number distribution，atom number and energy of ground state and give the parameter ranges. Compared to single-component BEC，two-component BECs exhibit a rich variety of ground state structures. These structures depend upon various parameters，in particular the inter-atomic interactions and the BLs strength. Neglecting the inter-component atomic interaction，the corresponding results of single-component situation are given.
Coherent state of hydrogen-like atoms: an application of the pseudo-angular-momentum operator method
Authors: Li Wen-Bo  , Li Mi-Shan  ,   北京交通大学物理系，北京  100044
Published: December 2020

Using the pseudo-angular-momentum operator method，the radial equation for bound state of the hydrogen-like atom is solved and the analytical expression for the eigenstate is derived. The result shows that the normalization of eigenfunction should be done carefully owing to its peculiarity. The corresponding coherent state is also discussed.
Influence of Debye-screening on atomic energy levels and oscillator strengths
Authors: Li Yong-Qiang  , Wu Jian-Hua  , Yuan Jian-Min  ,   国防科技大学理学院物理系,长沙  410073
Published: December 2020

The influence of plasma screening on the energy levels and oscillator strength for ions in a high-temporary plasma is investigated by using the Debye-model. The 2s2—［2s1/2,2p1/2］1 and 2s2—［2s1/2,2p3/2］1 transitions of 11 beryllium-like ions from MnXXII to BrXXXII are calculated by including the effect of plasma-screening. The results show that the effect of plasma-screening increases the 2s2—［2s1/2,2p1/2］1 transition energy of beryllium-like ions, which leads to a blue-shift; it also shows that the blue-shift becomes more and more obvious as the plasma-screening increases. The overall trend for the oscillator strength of the 2s2—［2s1/2,2p3/2］1 transition is similar to that of the transition energy.
Theoretical study of electronic eqution of state for plasmas with transitional region
Authors: Zhu Xi-Rui  , Meng Xu-Jun  , Tian Ming-Feng  ,   北京应用物理与计算数学研究所,北京  100088
Published: December 2020

On the basis of the improved averaged atomic model,the distribution of the free electrons is dealt with by partial wave method in central field approximation to improve the precision of energy level and electron populations, The broadening of high electronic levels into bands is taken into account in a uniform approximation. Therefore,the precision of atomic inner energy and pressure is improved. As samples, the parameter of EOS of Mo, Au are calculated, respectively.
Measurements of dynamic yield strength of aluminum alloy and mechanism analysis of elastic precursor during reloading
Authors: Hu Jian-Bo  , Tan Hua  , Yu Yu-Ying  , Dai Cheng-Da  , Ran Xian-Wen  ,   (1)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; (2)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；国防科学技术大学理学院技术物理研究所，长沙  410073
Published: December 2020

Dynamic yield strength is one of the key variables in construction of the constitutive relationship for solids under shock loading. This paper reports the yield strength of LY12 aluminum alloy which was measured experimentally on the basis of the method proposed by J. R. Asay and L. C. Chhibildas, in which the test sample underwent a load-reload process and a load-unload process, and the particle velocity history at the LY12 Al sample/LiF transparent window interface was observed by velocity interferometer system for any reflecting surface (VISAR). Improvement in fabrication of the layered flyer plate made these experiments successful. The measured yield strength data at shock stresses of 22GPa and 34GPa are consistent with the reported data at relatively lower pressures. Moreover, physical mechanism of the elastic precursor emerging in the reloading-process was discussed briefly. It is concluded that dislocations is the principal factor resulting in the elastic precursor.
Fit parameter to calculate transition probability
Authors: Shen Xiao-Zhi  , Yuan Ping  , Wang Jie  , Guo Yi-Xiao  , Qiao Hong-Zhen  , Zhao Xue-Yan  ,   (1)西北师范大学物理与电子工程学院,兰州  730070; (2)西北师范大学物理与电子工程学院,兰州  730070；中国科学院寒区旱区环境与工程研究所,兰州  730000
Published: December 2020

According to the relative intensities of lines and transition parameters, through linear fit of linear function, two fit parameter are obtained. And by adopting these parameters, transition probabilities of spectral lines for special configuration or highly excited states can be calculated. In the present work, on the basis of spectroscopic analysis for N+ spectra, the transition probability whose upper states are pair coupling is obtained. The present work gives a simple and feasible new semi-classical method to calculate transition probabilities, especially for special configurations or highly excited states.
The research of left-handed material using unsplit FDTD method
Authors: Fu Jia-Hui  , Meng Fan-Yi  , Yang Guo-Hui  , Wu Qun  , Liu Xin-Lei  ,   哈尔滨工业大学,哈尔滨  150001
Published: December 2020

In order to certificate the electromagnetic characteristic of left-handed materias (LHM), we adopt unsplit finite-difference time domain method (FDTD) to the ideal Drude model of LHM. This method does not need to split the electric and magnetic fields and does not need the use of special treatment of PML. PML and working space can be converted with the parameters. The penetrating wave will be attenuated in the PML which is set up by lossy dielectric. So it is an effective method to analyze dispersion and anisotropic material. Thus we can confirm the LHM and its unique characteristics such as negative refraction, convergent and phase compensation and verify the effectiveness of analyzing LHM using unsplit FDTD.
Emission properties of high-order harmonic generation
Authors: Ge Yu-Cheng  ,   北京大学技术物理系和核物理与核技术国家重点实验室，北京  100871
Published: December 2020

Reported are the emission properties (energy-time distributions) of high-order harmonic generation (HHG) calculated for lasers of different pulse durations (τL, in units of radian) in full width at half maximum (FWHM) and different carrier-envelope phases (CEPs,Φ). Calculations demonstrate that the cutoff energy of HHG spectrum produced by a few-cycle laser is less than that by an infinite duration laser (ωmax=3.17Up+Ip, where　ωmax is the angular frequency of the photon, Up the ponderomotive potential of the laser field, and　Ip the atomic ionization potential). A τL＝4π rad,　Φ＝15° laser can produce a single distribution pulse peaked at 0.94 rad and spanning 1.29 rad with a cutoff energy ωmax=2.90Up+Ip and a bandwidth 0.86Up. For the same laser but with Φ＝-75°, double distribution pulses occur with equal amplitudes, cutoff energy　ωmax=2.70Up+Ip and bandwidth 0.70Up. These two pulses are peaked at -0.58 rad and 2.43 rad，span 1.22 rad and 1.33 rad, respectively. Calculations also demonstrate that the bandwidth of a selected distribution pulse decreases much faster than its duration as the laser duration grows. The CEP dependence of the single distribution pulse parameters (its energy and time positions) show interesting 180° periodic structures. These features enable us to select attosecond pulse parameters and temporally control them by adjusting CEP. Theoretical analysis shows that the influences of CEP instability on the measured photoelectron spectra and the experimental results may be weakened to the maximum extent or even eliminated by choosing appropriate energy bandwidths of X-rays in attosecond measurements. All these results are helpful in realizing the HHG dynamic process. They can be used as new references in optimizing and selecting single and double attosecond pulses.
Controlling pulse duration of two-pulse laser to enhance alignment of N2 molecules
Authors: Yang Zeng-Qiang  , Zhou Xiao-Xin  ,   (1)西北师范大学物理与电子工程学院，兰州  730070; (2)西北师范大学物理与电子工程学院，兰州  730070；石河子大学师范学院物理系,石河子  832003
Published: December 2020

The method of enhancing the alignment of N2 molecules by controlling pulse duration of two-pulse laser is proposed. The time-dependent Schrdinger equation of the rigid rotor model of N2 molecule in the two-pulse laser is solved numerically by using the pseudospectral method. The degree of alignment for N2 molecules by laser pulses with different durations is calculated. The results show that the alignment can be optimized by selecting the pulse duration and the delay time between the two pulses.
Accurate studies on rovibrational energies of the electronic state B1Σ of HF molecule using an algebraic approach
Authors: Fan Qun-Chao  , Sun Wei-Guo  , Qu Shuang-Shuang  ,   四川大学原子与分子物理研究所，成都  610065
Published: December 2020

Based on the algebraic method (AM) presented in our previous study, a new algebraic approach (AM2) is suggested to evaluate accurate rovibrational energies and corresponding rotational constants using known experimental data of rovibrational energies of limited accuracy of a given rovibrational band for a diatomic electronic state. The results of reseach on rovibrational energies of the B1Σ electronic state of HF molecule shows that Algebraic Method 2 gives rovibrational energies in excellent agreement with experimental data, and the method generates reliable energies of high-lying rovibrational excited states which may be difficult to obtain experimentally or theoretically.
The study of optimal fitting parameter for C 1s spectra of SiC surface
Authors: Ma Ge-Lin  , Zhang Yu-Ming  , Zhang Yi-Men  , Ma Zhong-Fa  ,   宽禁带半导体材料与器件教育部重点实验室，西安电子科技大学微电子学院，西安  710071
Published: December 2020

X-ray photoelectron spectroscopy (XPS)is highly adapt to characterize the chemical states of the surface of SiC samples. However, there were notable discrepancies in results for C ls spectra from fitting XPS data reported by using the method of fixed number and peak values (or full width half maximum) of peaks in different previous papers. In this paper, a novel XPS fitting method is proposed by adopting variable peak values (full width half maximum) and peak areas of peaks, and then the effects of number of peaks, functional types of peak and background on fitting results of the C 1s spectroscopy for SiC surface have been investigated. Comparing the XPS wide-scan spectroscopy and infrared glancing reflection absorption spectroscopy, optimal fitting parameters and fitting result for C 1s spectroscopy of SiC surface are determined. The binding energies of C 1s photoelectron spectroscopy obtained in this paper have the same values as that reported. All this establishes the basis for fitting narrow scan spectroscopy of elements and the investigation of chemical state structure of the surface of SiC and other materials.
Spin-orbit ab initio calculation of photodissociation of methyl iodide
Authors: Li Rui  , Yan Bing  , Zhao Shu-Tao  , Guo Qing-Qun  , Lian Ke-Yan  , Tian Chuan-Jin  , Pan Shou-Fu  ,   吉林大学原子与分子物理研究所，长春  130012
Published: December 2020

The effective potential energy curves correlated to 2I03/2 and 2I01/2* atom limits are calculated using second order spin-obit multiconfigurational quasidegenerate perturbation theory (SO-MCQDPT). The absorption spectra of CH3I molecule are calculated, photodissociation processes of CH3I molecule are analyzed and the quantum yields of 2I01/2* atom are estimated. The present calculations can be used to interpret the experimental results.
Studies on the momentum transfer cross sections for low-energy electron scattering by nitrogen molecule
Authors: Yu Jiang-Zhou  , Feng Hao  , Sun Wei-Guo  ,   (1)四川大学物理科学与技术学院,成都  610065; (2)四川大学原子分子物理研究所,成都  610065
Published: December 2020

In this paper, momentum transfer cross sections are obtained using body frame vibrational close-couple method (BFVCC) modified by the authors. Using the static potential, correlation-polarization potential and exchange potential calculated ab-initio, the results accord with experiment very well.