bluuebunny/crossref_metadata_2025 huggingface dataset:
Sunspot number prediction based on process neural network with time-varying threshold functions
Authors: Ding Gang  , Zhong Shi-Sheng  ,   哈尔滨工业大学机电工程学院,哈尔滨  150001
Published: December 2020

The activity of the sunspot influences the space environment directly. In order to guarantee the flight safety of the spacecraft in the space, it is necessary to predict the sunspot number effectively. To solve this problem, a time series prediction model based on the process neural network with time-varying threshold functions is proposed. To simplify the calculation, a learning algorithm based on the expansion of the orthogonal basis functions is developed. The functional approximation capability of the proposed prediction model is analyzed, and the effectiveness of the prediction model and its learning algorithm is validated by the prediction of the Mackey-Glass time series. Finally, the proposed time series prediction model is utilized to predict the smoothed monthly mean sunspot numbers in solar cycle 23, and the results are satisfying. The application results also indicate that in comparison to other traditional prediction methods, the prediction method used in this paper has a higher prediction accuracy, thus it has theoretical meaning and practical value for the space environment prediction.
Influence of noise on self-trapping of Bose-Einstein condensates in double-well trap
Authors: Liu Ze-Zhuan  , Yang Zhi-An  ,   济南大学理学院，济南 250022
Published: December 2020

In this paper we study self-trapping of Bose-Einstein condensates in a symmetric double-well potential with uniform noise or Gaussian noise existing respectively. We find that both uniform noise and Gaussian noise destroy the critical behavior of self-trapping with the interaction increasing and create a transition zone between Josephson oscillation and self-trapping, between which exists a critical point originally. Furthermore, the stronger the noise becomes, the wider the transition zone is. Meanwhile, we find that the phase space falls into complete confusion when we increase noise intensity to a certain extent with interaction fixed, and the trajectories reappear after we increase the interaction without increasing the noise intensity. In the full-quantum situation, when noise exists there is a transition zone instead of a critical value, and stronger noise creates wider transition zone, which is the same as in mean field treatment. What is different is that in full-quantum situation noise creates self-trapping, and the stronger the noise, the more obvious the self-trapping becomes.
A time-resolved three-channel soft X-ray spectrometer
Authors: Hu Xin  , Jiang Shao-En  , Cui Yan-Li  , Huang Yi-Xiang  , Ding Yong-Kun  , Liu Zhong-Li  , Yi Rong-Qing  , Li Chao-Guang  , Zhang Jing-He  , Zhang Hua-Quan  ,   (1)哈尔滨工业大学精密工程研究所，哈尔滨 150001; (2)中国工程物理研究院机械制造工艺研究所，绵阳 621900; (3)中国工程物理研究院激光聚变研究中心，绵阳 621900
Published: December 2020

Developing of a time-resolved three-channel soft X-ray spectrometer is reported，and the operating principle and the parameters of spectrometer designed in three energy bands of 210eV，420eV and 900eV are presented specially. On the ShenGuang-Ⅱ high power laser facility，the spectrometer was applied in experiments with good results. This work is the first attempt in China to construct a spectrometer which couples planar mirrors and filters to X-ray streaked camera，and which is capable of measuring X-ray signal with spatial- and temporal-resolution in three sub-Kev energy channels simultaneously. Experimental results show that by combining X-ray reflector and filter，the spectrometer has achieved enery resolution of 5 and temporal resolution ability of 10 ps.
Study on the interaction of microdischarge channels in dielectric barrier discharge pattern
Authors: Dong Li-Fang  , Gao Rui-Ling  , He Ya-Feng  , Fan Wei-Li  , Li Xue-Chen  , Liu Shu-Hua  , Liu Wei-Li  ,   河北大学物理科学与技术学院，保定 071002
Published: December 2020

The spatial wavelength of the hexagon pattern are studied for different discharge parameters in dielectric barrier discharge system near the atmospheric pressure. The generating process and the movement of the microdischarge channels are observed. It is found that the wavelength of the hexagon decreases as the applied voltage increases. It is also dependent upon the gas gap and the gas pressure. The new filaments appear near the discharge boundary when the applied voltage increases slowly. The filaments at the outmost vertexes of hexagon move along the radial axis. The filaments on the side of hexagon move along axis parallel to the C2 axis, which has the least distance to those filaments. The discharge spots change into discharge stripes and finally into the spiral or target pattern when the applied voltage is increased further. Based on the experimental results and the force analysis, the confined potential, which exists in two dimensional coulomb crystals, is proposed to exist in the discharge domain.
Freezing of Ni nanowires investigated by molecular dynamics simulation
Authors: Zhou Guo-Rong  , Gao Qiu-Ming  ,   中国科学院上海硅酸盐研究所，高性能陶瓷和超微结构国家重点实验室，上海 200050
Published: December 2020

The freezing of Ni nanowires at different cooling rates was studied by classical molecular dynamics simulation via embedded atom potential method. The structure evolution of Ni nanowires in the freezing region was also presented. In order to distinguishing the local clusters in the cooling process of Ni nanowires formed at different cooling rates the bond, pair analysis is employed. The simulation results indicate that the freezing of the nanowires starts from the surface and the structure of the nanowires changes from amorphous to fcc crystal via helical multi-shelled structure along with the decrease of cooling rate. The helical multi-shelled structure possesses not only the short-range order and long-range disorder of amorphous structure but also a definite crystallization temperature.
Effect of foreign particles on the dendritic growth in phase-field theory
Authors: Li Jun-Jie  , Wang Jin-Cheng  , Xu Quan  , Yang Gen-Cang  ,   西北工业大学凝固技术国家重点实验室，西安 710072
Published: December 2020

The presence of foreign particles in the undercooled melt can influence the evolution of solidification structure and change the dendritic morphology. In this work, according to the KKS model, a hybrid phase field model for binary alloys, which takes into account the random crystallographic orientation, is developed to analyze the effect of misorientation between foreign particles and crystal grains on the dendritic growth. The simulation results show that the influence of foreign particles depends on the particle size, position, numbers and the degree of misorientation. The foreign particles which do not match the initial orientation of the crystal cause the dendrite trunks to deflect and split, leading to the formation of irregular dendritic morphology.
Electron irradiation induced defects in high temperature annealed InP single crystal
Authors: Wang Bo  , Zhao You-Wen  , Dong Zhi-Yuan  , Deng Ai-Hong  , Miao Shan-Shan  , Yang Jun  ,   (1)四川大学物理科学与技术学院应用物理系,成都 610065; (2)中国科学院半导体研究所,北京 100083
Published: December 2020

Electron irradiation induced defects in InP material which has been formed by high temperature annealing undoped InP in different atmosphere have been studied in this paper. In addition to Fe acceptor, there is no obvious defect peak in the sample before irradiation, whereas five defect peaks with activation energies of 0.23 eV, 0.26 eV, 0.31 eV, 0.37 eV and 0.46 eV have been detected after irradiation. InP annealed in P ambient has more thermally induced defects, and the defects induced by electron irradiation have characteristics of complex defect. After irradiation, carrier concentration and mobility of the samples have suffered obvious changes. Under the same condition, electron irradiation induced defects have fast recovery behavior in the FeP2 ambient annealed InP. The nature of defects, as well as their recovery mechanism and influence on material property have been discussed from the results.
Spin polarized transport properties for quantum wire irradiated by THz electromagnetic wave
Authors: Xiao Xian-Bo  , Li Xiao-Mao  , Zhou Guang-Hui  ,   (1)湖南师范大学物理系,长沙 410081; (2)江西农业大学物理系,南昌 330045
Published: December 2020

We theoretically study the spin-polarized electron transport properties of a quantum wire under irradiation of a transversely polarized external electromagnetic (EM) wave in the presence of Rashba spin-orbit interaction (SOI). Using the free-electron model and the scattering matrix approach, we show that spin polarization is independent on the EM frequency and the electron incident energy when Rashba SOI is weak, while it is strongly dependent on the EM frequency and the incident energy when Rashba SOI is comparatively strong. In addition, an unusual step-structure appears in the electronic transmission probability as the incident energy increases to a threshold value when a coherent EM field is applied. We demonstrate that the first effect comes from Rashba subband intermixing and the latter comes from inelastic scattering of electrons with lateral photons through intersubband transitions.
Spectroscopy studies of methyl orange on silver colloids: pH and Cl－ effects
Authors: Zhang Ai-Ping  , Fang Yan  ,   首都师范大学北京市纳米光电子学重点实验室,北京  100037
Published: December 2020

The UV-Vis absorption and photoluminescence spectral signals of silver colloids and methyl orange (MO) in different pH systems before and after adding Cl- were studied. It was found that the energy transfer efficiency changes with the pH value, i.e., the fluorescence quenching at 428 nm and photoluminescence enhancement at 560 nm was greatly strenthened with the increase of pH of the system. After adding Cl-, dense adsorption layer was formed, leading to stronger spectral signals associated with surface enhancement. On the other hand, because of the decrease of incident light to the inside of Ag-MO complex, energy transfer channel may be suffocated to some extent, the quenching amplitude of 428 nm fluorescence band decreased. Compared with these notable phenomena and discussed with correlative theoretic analysis, it's clear that different molecular structures and adsorption models of MO onto Ag surfaces exist with the changing of pH and the adding of Cl-, which give rise to the different phenomena observed.
Reflected Gaussian beam splitting phenomenon in the thin-film Fabry-Perot filter
Authors: Li Ming-Yu  , Liu Xu  , Zhang Jin-Long  , Ma Xin  , Li Yi-Yu  , Sun Xue-Zheng  , Gu Pei-Fu  ,   (1)国家纳米科学中心，北京 100080; (2)浙江大学现代光学仪器国家重点实验室，杭州 310027
Published: December 2020

A numerical method to simulate the splitting of the reflected Gaussian beam in the thin-film Febry-Perot filter is described. The splitting can be simply explained by studying the reflection curve. The thin-film Febry-Perot filter has been fabricated by coating TiO2 and SiO2 on glass. The reflected beam splitting phenomenon is observed and measured in practice. The theoretical result is in accord with the experimental result.
High quality SnO2 crystals grown with catalyst-assistance and study on their photoluminescent spectroscopy
Authors: Ding Cai-Rong  , Wang Bing  , Yang Guo-Wei  , Wang He-Zhou  ,   中山大学光电材料与技术国家重点实验室，广州 510275
Published: December 2020

SnO2 nanocrystals were synthesized, and their photoluminescence spectra revealed the following results. Firstly, we found that the main emission peak of the sample grown with catalyst-assistance is the emission peak of band gap (3.68 eV), and the photoluminescence efficiency of the crystal grown with catalyst-assistance is much higher than that without it. These results show that the quality of the crystal grown with catalyst-assistance is much improved. Furthermore, the emissions of twin-born crystal surfaces (101) and (101)T are demonstrated from the results of the deconvolution of photoluminescence spectra.
The effect of composition of the catalysts on the preparation of single-walled carbon nanotubes
Authors: Niu Zhi-Qiang  , Fang Yan  ,   北京市纳米光电子学重点实验室，首都师范大学物理系,北京 100037
Published: December 2020

The Mo-Co-MgO and W-Co-MgO catalysts were first prepared by the citric acid method. The single-walled carbon nanotubes(SWCNTs) were synthesized by decomposing CH4 in Ar over the Mo-Fe-MgO，Mo-Co-MgO and W-Co-MgO catalysts at 1123 K in the fluidized bed reactor. The effects of composition of the catalysts on the synthesis of SWCNTs were studied by Raman spectroscopy and transmission electron microscopy (TEM). And the mechanism of growth of SWCNTs was discussed. The results show that the citric acid method is effective for to preparing the catalysts and the high-quality SWCNTs were synthesized over the three catalysts. At 1123 K, the growth of SWCNTs over the catalysts may be similar to the liquid micro-area model. The dependence of diameter distribution on the composition of the catalysts was weak. There were some differences in the inner structure of SWCNTs synthesized over the three different catalysts. The carbon yield rates of products were increased by the addition of W and Mo in the catalysts.
Effect of far field flow on the spherical crystal in the undercooled melt
Authors: Chen Ming-Wen  , Wang Zi-Dong  , Sun Ren-Ji  ,   (1)北京科技大学材料科学与工程学院,北京 100083; (2)北京科技大学应用科学学院,北京 100083; (3)北京科技大学应用科学学院,北京 100083；北京科技大学材料科学与工程学院,北京 100083
Published: December 2020

The influence on the growth morphology of the spherical crystal in the undercooled melt imposed by the far field flow is studied by the asymptotic method. It is shown that the far field flow leads to convection in the melt such that the front interface of a growing spherical crystal grows into the undercooled melt in the opposite direction to the flow and enhances the growth rate in the same direction, while the back interface of the growing spherical crystal decays. On the other hand, the front interface of a shrinking spherical crystal further decays, and the back interface of the shrinking spherical crystal decays slower.
The closed solution and verification of the electromagnetic field of a vertical dipole over the sphere
Authors: Wang Hai-Long  , Wu Qun  , Li Le-Wei  , Wu Jian  , Meng Fan-Yi  ,   (1)哈尔滨工业大学电子与信息技术研究院，哈尔滨  150001; (2)哈尔滨工业大学电子与信息技术研究院，哈尔滨  150001;电波环境特性及模化技术国家重点实验室，北京  102206; (3)哈尔滨工业大学电子与信息技术研究院，哈尔滨  150001;新加坡国立大学电气与计算机工程系，新加坡
Published: December 2020

The closed solution of the electromagnetic filed of the vertical dipole over a perfect conducting sphere is introduced，the problem of discontinuity encountered in the series expression of the direct field is solved. Computation result is compared with the direct summation of the series form solutions of the electromagnetic filed over the sphere. Based on the same electromagnetic model, an approximate method is verified by the closed solution. If the vertical dipole and the observation point are near the surface of the sphere and the frequency is not too high, then the computation results of the two methods are guite the same. If the vertical dipole and the observation point are not near the surface of the sphere and the frequency is high, then the behavior of interference is gradually obtained by the closed solution but not by the approximate method.
Three-dimensional surface contouring of reflecting micro-object by digital holography with short-coherence light source
Authors: Yuan Cao-Jin  , Zhai Hong-Chen  , Wang Xiao-Lei  , Wu Lan  ,   (1)南开大学现代光学研究所，光电信息技术科学教育部重点实验室，天津  300071; (2)浙江大学光学工程系，现代光学仪器国家重点实验室，杭州  310027
Published: December 2020

In this paper, a new lensless digital holography system with short-coherent light source is designed for recording three-dimensional surface contour of reflecting micro-object. In the experiment, the different layers on the inner wall of a conical pore are recorded by changing the path length of object beams to record a series of sub-holograms for three-dimensional reconstruction. This makes the recording system compact and reduces the additional error in the recording. The measured longitudinal error is about 3.5%，with a lateral error of about 2.6%. Besides, the least squares polynomial fit method is used for the first time to carry out three-dimensional reconstruction with a series of two dimensional intensity images of a micro-object, which not only reduces obviously the complication of the three-dimensional reconstruction, but also can be used to carry out three-dimensional reconstruction of a micro-object with strong laser speckle noise, of which the phase images can not be obtained from the phase-unwrapping process.
Theoretical study on temporal behavior of Brillouin-enhanced four-wave mixing
Authors: Zhu Cheng-Yu  , Lü Zhi-Wei  , He Wei-Ming  , Ba De-Xin  , Wang Yu-Lei  , Gao Wei  , Dong Yong-Kang  ,   哈尔滨工业大学光电子技术研究所，哈尔滨  150001
Published: December 2020

The nature of Brillouin-enhanced four-wave mixing (BEFWM) temporal modulating behavior is examined numerically. The evolution of the acoustic wave, which plays a key role in the process of energy inter-coupling, is simulated and analyzed. Based on this, the detailed mechanism of BEFWM temporal characteristics is explained. It is demonstrated that, modulations in the conjugate wave are related with the distribution and fluctuation of the acoustic wave, and influenced by parameters such as phonon lifetime, intensity of the signal and pump wave, effective interaction length, and so on.
Theoretical study on coupling betwecn nonparallel waveguides
Authors: Liang Hua-Wei  , Shi Shun-Xiang  , Li Jia-Li  ,   西安电子科技大学技术物理学院，西安 710071
Published: December 2020

Coupling between nonparallel waveguides is studied by coupling mode theory, and the coupling equations and coupling coefficients are obtained. Using small angle approximation, results under several conditions are obtained,which are then compared with that of another method. Although both methods indicate that the optical power approaches to a stable value at positions far from the input,yet the values of optical power obtained by them are quite different. To be specific, near the input, optical power changes more violently with propagation distance for the method used by us. Since the effects of both optical amplitude and phase on the coupling equations and coupling coefficients are considered fully in the present method, our results are more comprehensive in describing the coupling of nonparallel waveguides and should be more meaningful for practical applications.
Theoretical study of the effect of potential models on scattering cross sections for He-HF system
Authors: Yu Chun-Ri  , Wang Rong-Kai  , Cheng Xin-Lu  , Yang Xiang-Dong  ,   (1)安庆师范学院物理与电气工程学院，安庆 246011；四川大学原子与分子物理研究所，成都 610065; (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

An anisotropic intermolecular potential of the He-HF complex has been obtained by utilizing the BFW analytic function to fit the intermolecular energy data, which have been calculated at the theoretical level of the single and double excitation coupled-cluster method with noniteractive perturbation treatment of triple excitation CCSD (T). And the reliability of the potential has been verified by comparing it with other potential models. The differential, partial and total scattering cross sections for collisions between He atoms and HF molecules have been calculated respectively by using the quantum close-coupling method at five different potential models, and the calculated results have been compared and analysed in detail. The research shows that the scattering cross sections are sensitive to the position where potential is zero, the well depth, the strength of the repulsive wall of the spherically averaged and to the anisotropy of the region of the well depth. We hope that the results can provide profitable reference for determining exactly the interaction potential of the atomic-molecular collision systems from the scattering cross sections.
On the second Born approximation for laser-assisted e-Ar scattering
Authors: Sun Jin-Feng  , Wang Xiao-Fei  , Zhu Zun-Lüe  , Hu Qiu-Bo  ,   (1)河南师范大学物理与信息工程学院，新乡 453007; (2)河南师范大学物理与信息工程学院，新乡 453007；洛阳师范学院物理与电子科学系，洛阳 471022; (3)河南师范大学物理与信息工程学院，新乡 453007；四川大学原子与分子物理研究所，成都 610065
Published: December 2020

The absolute differential cross sections of e-Ar scattering in laser field are calculated employing the second Born approximation with the static screen potential including polarization potential and the single static screen potential in the special scattering geometry that the incident electron beam is parallel to the polarization direction of laser field. The second Born approximation gives better results than the low-frequency whem formula when compared with the experimental data, and it is found that the electron-atom polarization potential plays an important role in laser-assisted electron-atom scattering.
Improving the optical profile of electroabsorption modulator using single-sided large optical cavity structure
Authors: Yang Hua  , Zhu Hong-Liang  , Pan Jiao-Qing  , Feng Wen  , Xie Hong-Yun  , Zhou Fan  , An Xin  , Bian Jing  , Zhao Ling-Juan  , Chen Wei-Xi  , Wang Wei  ,   中国科学院半导体研究所，国家光电子集成重点实验室，北京 100083
Published: December 2020

An electroabsorption modulator with large optical cavity was designed and fabricated successfully. Both the simulated and experimental results show that, the larger optical cavity structure introduced could obviously improve the optical profile of EA modulator, the traditional elliptical near-field spot becomes more rounded, so it will match better with the optical fiber and is beneficial for raising the coupling efficiency.
Bistability-mapping of L-band dual-wavelength erbium-doped fiber laser based on fiber loop mirror
Authors: Mao Qing-He  , Feng Su-Juan  , Jiang Jian  , Zhu Zong-Jiu  , Liu Wen-Qing  ,   中国科学院安徽光学精密机械研究所,合肥  230031
Published: December 2020

A technique for controlling and mapping the optical bistability of an L-band dual-wavelength erbium-doped fiber laser (EDFL) with cascaded linearly coupled cavities was presented and demonstrated in this paper. By using a fiber loop mirror (FLM) with a polarization controller (PC) in the loop as the common mirror of the laser, we found that the bistability of the laser may be efficiently controlled by adjusting the reflectivity of the FLM which is determined by the PC state. Moreover, the bistability varies monotonically with the reflectivity of the FLM. By making use of this property, the two stable states and the two potential lasing wavelengths of the laser may be respectively mapped and switched with respect to each other by adjusting the PC for any fixed pump powers, as long as the pump power lies between the first turning point of the bistability for the maximum reflectivity of the FLM and the second turning point of the bistability for the minimum reflectivity of it.
A new type of conserved quantity of Mei symmetry for Hamilton system
Authors: Fang Jian-Hui  , Ding Ning  , Wang Peng  ,   中国石油大学(华东)物理科学与技术学院，东营  257061
Published: December 2020

A new type of conserved quantity which is directly induced by Mei symmetry of Hamilton system is studied. Firstly, the definition and criterion of Mei symmetry for Hamilton system are given. Secondly, a coordination function is introduced; the conditions from which the new type of conserved quantity can be induced by Mei symmetry and the form of the new type of conserved quantity are obtained. Lastly, an illustration example is given. The result indicates that the coordination function should be selected properly according to the demand of the gauge function, thereby the gauge function can be find out more easily. Furthermore, since the choice of the coordination function is not unique more conserved quantities of Mei symmetry for Hamilton system can be obtained.
A fiber sensor for measuring gas concentration based on laser’s transient regime
Authors: Guo Wen-Gang  , Yang Xiu-Feng  , Luo Shao-Jun  , Li Yong-Nan  , Tu Cheng-Hou  , Lü Fu-Yun  , Wang Hong-Jie  , Li En-Bang  , Lü Chao  ,   (1)Lightwave department,Institute for Infocomm Research,Singapore  637723; (2)南开大学物理科学学院光电信息科学系，天津  300071; (3)南开大学物理科学学院光电信息科学系，天津  300071;Lightwave department,Institute for Infocomm Research,Singapore  637723; (4)天津大学精密仪器与光电子工程学院，天津  300072
Published: December 2020

A novel fiber sensor for measuring gas concentration is reported, which is based on the transient regime of a Er-doped fiber laser. A Sagnac fiber loop and a FBG that also acts as the sensing element form the linear fiber laser cavity. By adjusting the central wavelength of the grating mirror, the oscillating wavelength is set to 1531.56 nm, which is a strong absorption peakof C2H2. The gas concentration can be obtained by measuring the laser build-up time, which is closely related with the cavity loss and therefore determined by the gas concentration. In the present experiment, the sensor's sensitivity and resolution can be adjusted simply by controlling the pumping level. When the pump pulse is at high level and low level of 25 mW and 5.9 mW, respectively, a sensitivity of 100 ppm/μs and resolution of 20 ppm are achieved.
Generalized synchronization of two non-identical chaotic systems based on fuzzy model
Authors: Yang Dong-Sheng  , Zhang Hua-Guang  , Li Ai-Ping  , Meng Zi-Yi  ,   (1)东北大学信息科学与工程学院，沈阳  110004; (2)东北大学信息科学与工程学院，沈阳  110004; 东北大学教育部暨辽宁省流程工业综合自动化重点实验室，沈阳  110004
Published: December 2020

This paper deals with the problem of generalized synchronization via T-S fuzzy models for two non-identical chaotic systems.A H∞ control method based on T-S fuzzy model is presented. A sufficient condition for synchronization of two non-identical systems is obtained based on Lyapunov functional method and matrix inequality techniques. Finally, an example is provided to demonstrate the effectiveness of the proposed method.
The sine-squared potential and the band structure for channelling effects
Authors: Shao Ming-Zhu  , Luo Shi-Yu  ,   东莞理工学院,东莞 523106
Published: December 2020

The interaction between the charged particle and the crystal is described by quantum mechanics. The schrdinger equation describing a paticle moving in the channel is reduced to Mathieu equation by using a sine-squared potential. The band structure of this system is discussed based on Bloch theorem. The instability zone and the stop-band width are found by the perturbation techniques. It is shown that the width of the 1-st order and 2-nd order instability zones are ΔE1=Kβ/2 and ΔE2=md2p(Kβ)2/16π22, respectively, and this system presents automatical the band structure, which is not present in Lindhard potential and Moliere potentials.
Analytical calculation of temperature distribution and thermal deformation during doping of Zn in GaN/Al2O3 material induced by nanosecond pulse-width laser
Authors: Huang Sheng-Rong  , Chen Chao  ,   厦门大学物理系,厦门 361005
Published: December 2020

The process of doping of Zn into GaN induced by nanosecond pulse laser is analyzed in this paper. An analytical formula of temperature distribution in GaN material irradiated by pulsed laser is presented using one_dimensional model. The relation of surface temperature versus irradiation time and thermal deformation versus depth are obtained. The results show that the surface temperature is in proportion to the square root of irradiation time. The distributions of temperature and thermal deformation in the material are also obtained. The temperature gradiant and the thermal deformation are all highest near the surface. However, the temperature of surface increases in a saw_tooth manner when the material is irradiated continuously by pulseed laser.
Current-induced effects in La0.9Sr0.1MnO3 film
Authors: Luo Bing-Cheng  , Chen Chang-Le  , Gao Guo-Mian  , Jin Ke-Xin  , Han Li-An  ,   西北工业大学理学院，西安 710072
Published: December 2020

La0.9Sr0.1MnO3 film has been fabricated on (100) LaAlO3 by direct-current magnetron sputtering. The quality of the film is good as monitored by atom force microscopy and X-ray diffraction. The resistivity-temperature curve shows that the film undergoes metal-insulator transition at 281 K. The peak resistivity decreases with increasing current and the current-induced electro-resistance is 30.5% at 4 mA. The results are simply explained by phase-separation theory.
Research on diffraction enhanced imaging computed tomography technique
Authors: Wang Min  , Hu Xiao-Fang  ,   (1)安徽工业大学机械工程学院，马鞍山 243002; (2)中国科学技术大学中国科学院材料力学行为和设计重点实验室，合肥 230026
Published: December 2020

The technique of diffraction enhanced imaging computed tomography is studied in this paper and a new algorithm is given. The absorption, scattering and refractive index gradient can be obtained using the new algorithm with projection data of an object in the rotation range of 0°—360° and only needs to set the analyzer at one point of the rocking curve. The experimental process of the new algorithm is much simpler than the conventional.
The effect of balanced homodyne detection on continuous variable quantum key distribution
Authors: Chen Jin-Jian  , Han Zheng-Fu  , Zhao Yi-Bo  , Gui You-Zhen  , Guo Guang-Can  ,   中国科学技术大学，中科院量子信息重点实验室，合肥  230026
Published: December 2020

Different from single photon quantum key distribution, continuous variable quantum key distribution uses the balanced homodyne detection. In this paper, the detection error of balanced homodyne caused by vacuum noise of the local light and unbalance of beam splitter is analyzed, the maximal safe distance limited by the electronic noise of balance homodyne detector is given, finally, the relationship between the noise of balanced homodyne detection and key rate are shown.
Parameter estimation for Lorenz chaotic systems based on chaotic ant swarm algorithm
Authors: Li Li-Xiang  , Peng Hai-Peng  , Yang Yi-Xian  , Wang Xiang-Dong  ,   (1)北京邮电大学信息工程学院信息安全中心,145#,北京  100876;北京邮电大学国家网络和数据交换重点实验室,145#,北京  100876; (2)北京邮电大学信息工程学院信息安全中心,145#,北京  100876;沈阳工业大学信息科学与工程学院，沈阳  110023; (3)沈阳工业大学信息科学与工程学院，沈阳  110023
Published: December 2020

The chaotic ant swarm algorithm is a chaos optimization algorithm based on swarm intelligence theory which was inspired by the chaotic and self-organizing behavior of the ants in nature. It includes both effects of chaotic dynamics and swarm-based search. Through the construction of a suitable fitness function, the problem of parameter estimation of the chaotic system is converted to a problem of parameter optimization which could be solved via chaotic ant swarm algorithm. Chaotic ant swarm algorithm has the ability of global search. A numerical simulation on the well-known Lorenz chaotic system is conducted. Simulation results show that the proposed method is effective in parameter estimation of the chaotic system.
Adaptive control of a class of uncertain chaotic systems with dead-zone nonlinearity
Authors: Chen Jing  , Zhang Tian-Ping  , Lü Li-Xin  ,   (1)无锡科技职业学院信息工程系，无锡  214028; (2)无锡科技职业学院信息工程系，无锡  214028；扬州大学信息工程学院计算机系，扬州  225009; (3)扬州大学信息工程学院计算机系，扬州  225009
Published: December 2020

The tracking problem for a class of uncertain chaotic systems with dead-zone nonlinearity in the input function is considered in this paper. With the dead-zone nonlinearity in the controller, the disadvantage can be eliminated. The knowledge about the dead-zone nonlinearity in the input is unnecessary. To make this controller physically realizable, an extended state observer is used to estimate the unknown information. Numerical simulations are carried out to show the effectiveness of the design with respect to Duffing oscillator.
The κ-symmetry of Green-Schwarz superstring in some typical background
Authors: Wang Zhan-Yun  , Wang Xiao-Hui  , Shi Kang-Jie  , Yue Rui-Hong  ,   (1)西安邮电学院电子与信息工程系,西安  710121；西北大学现代物理研究所,西安  710069; (2)西北大学现代物理研究所,西安  710069
Published: December 2020

The action of type IIB superstring in AdS5S5 background given by Metsaev and Tseytlin(MT) can be reformulated in the Nambu-Goto form. For this form we give the new projection operator involving vielbeins in the target space to con-struct local κ-transformations which leave the action invariant. This new formulation of κ-symmetry(called target space form)is first suggested by Schwarz for the Green-Schwarz(GS) model. Due to the difference between GS model and MT model, our con-struction has some new aspects, which is applicable to all models similar to the MT model. An example is given for the AdS5S1 IIB superstring. We also study the κ-symmetry in target space form for the Polyakov model.
Vibrational spectrum of histidine and arginine in THz range
Authors: Wang Wei-Ning  , Li Yuan-Bo  , Yue Wei-Wei  ,   首都师范大学物理系，北京  100037
Published: December 2020

This paper reports the spectral characteristics of histidine and arginine in THz range by calculation and terahertz time-domain spectroscopy (THz-TDS). Absorption peaks are found at 0.88，1.64，2.23 THz (for histidine) and 0.99，1.47，2.60 THz (for arginine) by THz-TDS，respectively. The vibrational absorption spectra of the two molecules are calculated based on semi-empirical theory in the range of 0.1—10 THz. The calculated spectrum exhibits many absorption peaks and the first three of them are well comparable with the experiment results in the range of 0.2—2.8 THz. The vibration rotation modes corresponding to the absorption peaks of the molecules are presented. These results mutually validated both approaches, and can further be used in identification of molecules and experimental research in wider effective spectral range.
The description of bottle beam based on the interferential theory
Authors: Zeng Xia-Hui  , Wu Feng-Tie  , Liu Lan  ,   华侨大学信息科学与工程学院，泉州  362021
Published: December 2020

For the description of the focusing properties of a Bessel beam generated by an axicon, we first deduce a type of analytic expression other than Huygens-Fresnel diffraction integral theory. Based on the interferential theory, the analytic expression can be used to calculate the focusing beam evolution behind the focal plane of the positive lens and under the circumstance of the positive lens placed beyond the maximum non-diffraction distance, and can better illustrate the formation of the optical bottle beam. These results can not be described based on the Huygens-Fresnel diffraction integral theory. In addition, we get a different result from the one (that if z0max, hollow beam will be generated) obtained by Wei adopting geometrical optics. All of our theoretical calculations are confirmed by the experimental results.
The Goos-H?nchen shift on the surface of uniaxially anisotropic left-handed materials
Authors: Jiang Yong-Yuan  , Zhang Yong-Qiang  , Shi Hong-Yan  , Hou Chun-Feng  , Sun Xiu-Dong  ,   哈尔滨工业大学物理系，哈尔滨  150001
Published: December 2020

In this paper, the Goos-H?nchen shift on the interface of uniaxially anisotropic left-handed materials is investigated exhaustively, and the analytical expressions of Goos-H?nchen shift is presented for the cases of the optical axis being perpendicular and parallel to the interface, respectively. Moreover, the conditions for the existence and the sign of Goos-H?nchen shift are determined. Under Fresnel approximation, the expression of Goos-H?nchen shift around the critical angle is obtained, and the result shows that the shift around the critical angle is a function of the beam waist and incident angle. A simple approximate expression of the lateral shift with incident angle equals the critical angle is also presented. Thus, the general expression of Goos-H?nchen shift for any incident angles is obtained.
Realizing high density optical data storage by using orbital angular momentum of light beam
Authors: Liu Yi-Dong  , Gao Chun-Qing  , Gao Ming-Wei  , Li Feng  ,   北京理工大学信息科学技术学院光电工程系，北京  100081
Published: December 2020

The orbital angular momentum (OAM) states can be used to construct a high-dimensional Hilbert space, which implies higher data density when applied in data storage. This work proposes a method to realize high density optical data storage by using OAM of light beam, with the encoded area illuminated by a light beam with certain OAM resulting in distribution of power in the OAM states (the spiral spectrum or OAM spectrum), and detection of the power distribution conducing to its decoding. A quadrant staircase structure (QSS) used as an encoded element can realize 57 different states, and it is expected to enhance the data density 6 times as high as the conventional method.
Novel all-optical AND and NOR gates based on semiconductor fiber ring laser
Authors: Li Pei-Li  , Huang De-Xiu  , Zhang Xin-Liang  , Zhu Guang-Xi  ,   (1)华中科技大学武汉光电国家实验室，武汉  430074; (2)华中科技大学武汉光电国家实验室，武汉  430074;华中科技大学电子信息与工程系，武汉  430074
Published: December 2020

A new scheme for all-optical AND gate and NOR gate based on simultaneous four-wave mixing (FWM) and cross-gain modulation (XGM) in a semiconductor fiber ring laser (SFRL) is proposed, and a comprehensive broad-band dynamic model of this kind of all-optical logic gates is presented. By numerical simulation, the effects of the input signal peak power and the coupling of the couplers in SFRL on the output performances of the logic gates are analyzed.
Investigation on a high energy stimulated Brillouin scattering phase-conjugate mirror
Authors: Wang Yu-Lei  , Lü Zhi-Wei  , He Wei-Ming  , Zhang Yi  ,   哈尔滨工业大学光电子技术研究所，哈尔滨  150001
Published: December 2020

A novel dual-cell Brillouin oscillator-amplifier phase conjugate mirror for high energy and high peak power operation in double-pass solid state laser amplifier is described. Correction of static aberration and dynamic aberration induced in single-pass amplifier was achieved in the second passage through the aberrating medium under the condition of using the stimulated Brillouin scattering phase conjugate mirror as reflector. Output energy of 13 J was obtained with input energy of 7.1 J. An energy reflectivity of 65% and a conjugation fidelity of 90% were achieved by the use of this dual-cell phase conjugate mirror. Finally, the performance of this kind of SBS reflector in a double-pass amplifier has been compared to that of a flat mirror. The results show that the SBS reflector is highly effective in correcting the spatial aberrations of laser radiation. Excellent near-and far-field conjugation fidelities were obtained even with high input energy.
Theoretical study of wavelength conversion based on integrated twin-guide semiconductor optical amplifier optical switch
Authors: Miao Qing-Yuan  , Huang De-Xiu  , Zhang Xin-Liang  , Yu Yong-Lin  , Hong Wei  ,   华中科技大学武汉光电国家实验室和光电子科学与工程学院，武汉  430074
Published: December 2020

A model of integrated twin-guide semiconductor optical amplifier optical switch (ITG-SOA-Switch) is proposed. Comparison analyses with semiconductor optical amplifier (SOA) reveals that because of the combination of several physical effects by ITG-SOA-Switch, only a small increase of input power around 3 dB saturation point can cause a big decrease of gain. Theoretical analyes and the simulation results of 10Gbit/s wavelength conversion indicate that the extinction ratio of output converted signal of ITG-SOA-Switch can be greatly improved compared with that of input pump signal in a moderate pump power range.
Analysis of confinement loss in microstructured optical fibers with elliptical air holes
Authors: Wang Jian  , Lei Nai-Guang  , Yu Chong-Xiu  ,   (1)北京交通大学理学院, 北京  100044; (2)北京邮电大学电子工程学院,  北京  100876; (3)北京邮电大学电子工程学院,  北京  100876；北京交通大学理学院, 北京  100044
Published: December 2020

Confinement loss for the fundamental mode in the triangular lattice microstructured optical fibers with elliptical air holes is analyzed using the complex finite element method under the perfectly matched layer boundary condition. It is shown by the numerical results that the confinement losses decrease when the pitch of the air holes, the air-filling fraction and the rings of the air holes increase. In addition, the confinement losses are dependent on the fundamental mode polarization, and the confinement loss ratio of the y-polarized mode compared to the x-polarized mode increases with increasing pitch of the air holes, the air-filling fraction and the hole ellipticity. In the end, two kinds of highly nonlinear microstructured optical fibers that can achieve single-polarization, single mode transmission are designed.
Micro-Raman spectroscopic investigation of the thermal conductivity of oxidized meso-porous silicon
Authors: Fang Zhen-Qian  , Hu Ming  , Zhang Wei  , Zhang Xu-Rui  ,   天津大学电子信息工程学院,  天津  300072
Published: December 2020

A theoretical model describing the thermal conductivity of oxidized meso-porous silicon (meso-PS) was brought forward, which was based on the effective medium theory for the mechanisms of heat transfer in oxidized meso-PS. The factors affecting effective thermal conductivity (ETC) of oxidized meso-PS were analyzed theoretically, and a calculating formula of TC of oxidized meso-PS was given. Meso-PS samples were prepared by double-tank electrochemical corrosion method. Using Micro-Raman spectroscopic technique, the dependence of TC values of oxidized meso-PS samples on porosities of as-prepared meso-PS was studied and the thermal property of oxidized meso-PS with different oxidized temperatures was compared. TC values yielded by Micro-Raman spectroscopic technique of as-prepared meso-PS with porosities of 60%,73.4% and 78.8% oxidized at 300℃ were 8.625，3.846 and 1.817W/(m·K), respectively, while that of as prepared meso-PS with a porosity of 73.4% oxidized at 450℃ and 600℃ were 2.466 and 2.100 W/(m·K), respectively. And their corresponding theoretical ETC values were 4.549,2.432,1.792,2.105 and 2.096 W/(m·K), respectively. It was shown that the theoretical values were in good agreement with experimental data. Oxidized meso-PS with lower TC and desirable mechanical stability is well suited for thermal insulation material, which is attractive to the application in thermal-effect-micro-systems (TEMS).
On d-δ commutation relation of constrained differential systems
Authors: Guo Yong-Xin  , Zhao Zhe  , Liu Shi-Xing  , Liu Chang  ,   (1)辽宁大学物理学院和数学应用中心，沈阳  110036; (2)沈阳药科大学基础学院，沈阳  110016
Published: December 2020

An important problem of calculus of variations used in constrained differential systems, i.e., the commutation relation of differential operator and variational oprerator, is investigated by means of Frobenius theorem of integrability. Based on analyzing the d-δ commutation relation for the linear stationay differential constrained systems and affine differential constrained systems, the relationship between noncommutator of differentiation and variation and nonholonomicity of the differential constraints is briefly proved by means of Frobenius integrability theory. The commutation relation for non-linear differential constrained systems is also discussed in the paper. Finally, three examples are given to verify the results.
Adaptive dual-model control and synchronization of generalized Hénon chaotic systems
Authors: Liu Fu-Cai  , Liang Xiao-Ming  , Song Jia-Qiu  ,   燕山大学电气工程学院自动化系,秦皇岛  066004
Published: December 2020

A kind of adaptive dual-model control and synchronization algorithm for generalized Hénon chaotic system was proposed. Chaos attractor of generalized Hénon map is much more complicated than that of Hénon chaotic systems. It is more difficult to control and synchronize. The generalized Hénon chaotic systems under consideration makes the communications system more secure. This algorithm adopts adaptive dual-model control, which realizes the tracking control and synchronization of generalized Hénon chaotic systems, and meanwhile advances the ability of restraining the parameter perturbation and stochastic disturbance. The robustness performance of controlled system is improved. Theoretical analysis and simulation results proved the effectiveness of this method.
A dual-wavelength diode-end-pumped Nd:YAG laser operating simultaneously at 1319 and 1338nm
Authors: Liu Huan  , Yao Jian-Quan  , Zheng Fang-Hua  , Lu Yang  , Wang Peng  ,   天津大学精仪学院激光与光电子研究所,天津  300072;教育部光电信息技术科学重点实验室,天津  300072
Published: December 2020

Based on the lasing threshold equation of a diode-end-pumped Nd:YAG laser, the threshold condition of simultaneous dual-wavelength lasing is determined and the relationship between the transmission ratios of the output mirror corresponding to the two wavelengths is calculated. A simultaneous dual-wavelength continuous wave (cw) or quasi-cw diode-end-pumped Nd:YAG laser operating at 1319nm and 1338nm has been demonstrated. A total cw output power of 6W was achieved at a pump power of 21.6W with a slope efficiency of 30%. And a total quasi-cw output power of 4.75W was obtained at a pump power of 21.6W and a pulse repetition rate of 50kHz, with a slope efficiency of 24.73%, and the corresponding pulse width was 55.05ns. Inserting a Brewster plate in the cavity and the highest linearly polarized wave output power was boosted up to 2.22W at a pulse repetition rate of 50kHz. The instability of the output power was less than 0.52% and the beam quality M2 factor was as low as 1.16 at the linearly polarized wave output power of 2.17W. The simultaneous dual-wavelength laser provides an experimental basis for generating highly coherent terahertz wave radiation of 3.23THz by nonlinear optical difference frequency method.
A traffic flow model considering signal light influence and its numerical simulation
Authors: Tang Tie-Qiao  , Huang Hai-Jun  , Xu Gang  , Xue Yu  ,   (1)北京航空航天大学经济管理学院，北京  100083; (2)北京航空航天大学汽车工程系，北京  100083；北京航空航天大学经济管理学院，北京  100083; (3)广西大学物理科学与工程技术学院，南宁  530004
Published: December 2020

Based on the characteristics of car-following behavior in a road traffic system containing signal light，we improve the car-following equation and then present a traffic flow model which considers the signal light influence. Numerical results show that the model can reproduce such phenomena as flow clustering and dissipating，and capture the propagation of stopping and starting waves. It is concluded that the model proposed in this paper is reasonable.
Preparation and structure of NaREO2 (RE=Lu，Y)
Authors: Guo Ru-Wang  , Guo Chang-Xin  , Wu Di  ,   中国科学技术大学物理系，合肥  230026
Published: December 2020

NaLuO2 and NaYO2 powder crystals were prepared by the conventional solid state reaction method. It is more difficult to synthesize pure NaLuO2 powder crystals than NaYO2. To monitor the quantity of Lu2O3 in the NaLuO2 sample, we calculated the relation between weight ratio and XRD peak absolute intensity ratio of Lu2O3 to NaLuO2 by X-ray diffraction method, and obtained the constant (kLu2O3NaLuO2=3.8). Pure NaLuO2 powder crystals were obtained by optimizing reaction conditions (sintering temperature, reaction time, raw material molar ratio and fluxes) in a two-step method. The best reaction condition was found to be that the mixture of Na2O2, Lu2O3 and Na3PO4 at a molar ratio of 200∶100∶7 is filled into a small inner ceramic crucible which is placed inside a larger outer ceramic crucible and sintered at 850℃ for 3 h. The sample has pure hexagonal structure (space group R3m, lattice constant a＝0.3335 nm, c＝1.6545 nm). XRD pattern of NaLuO2 in this experiment indicated that there is an additional diffraction peak (006) compared with JCPDS23-0684, and the labeled (007), (111) and (117) peaks should be corrected to (104), (110) and (024) according to the Bragg reflection conditions of hexagonal system. Eu3+ doped NaLuO2 and NaYO2 have different emission spectra, which indicates that Eu3+ occupy different symmetric sites. The main peak of the former (having inversion centre i) is at about 590nm, corresponding to the magnetic dipole transition of Eu3+ (5D0→7F1), and the later (no inversion centre i) is at about 610nm, corresponding to the electric dipole transition of Eu3+ (5D0→7F2).