bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of diluted magnetic semiconductor GaMnN grown by electron cyclotron resonance-plasma enhanced metal organic chemical vapor deposition
Authors: Wang Ye-An  , Qin Fu-Wen  , Wu Dong-Jiang  , Wu Ai-Min  , Xu Yin  , Gu Biao  ,   (1)大连理工大学机械工程学院，大连  116024; (2)大连理工大学三束材料改性国家重点实验室，大连  116024
Published: December 2020

Diluted magnetic semiconductor film GaMnN was grown on sapphire (α-Al2O3) substrate using biscyclopentyldienyl manganese (Cp2Mn), N2 and TEGa by electron cyclotron resonance-plasma enhanced metal organic chemical vapor deposition(ECR-PEMOCVD) . The crystal structure and surface topography of the GaMnN films were characterized by RHEED, XRD and AFM. GaMnN films exhibit good (0002) preferred orientation, showing the films are inclined to c-axis growth and retain good wurtzite structure. The surface topography of GaMnN film is composed of many submicron grains piled in the consistent orientation. The magnetism of films is characterized by SQUID. SQUID shows that the film is ferromagnetic, which comes probably only from the ternary phase GaMnN and the Curie temperature of GaMnN film is higher than 350 K. Moreover, higher Mn concentration can enhance the Curie temperature of the film.
Study on the defect mode properties of unmagnetized plasma photonic crystals
Authors: Ma Li  , Zhang Hai-Feng  , Liu Shao-Bin  ,   (1)南昌大学机电学院，南昌  330031；中国人民解放军炮兵学院南京分院，南京  211132; (2)南昌大学理学院，南昌  330031; (3)南京航空航天大学信息科学与技术学院，南京  210016
Published: December 2020

The piecewise linear current density recursive convolution in finite-difference time-domain method is used to study the characteristics of one-dimensional unmagnetized plasma photonic crystals with a defect layer. In the frequency domain, the transmission ratios of electromagnetic Gaussian pulses are computed and we analyzed the effect on defect mode properties of unmagnetized photonic crystals produced by its periodic constant, parameters of plasma and parameters of the defect layer, such as its dielectric coefficient, length and position. The results show that different defect modes can be realized by changing the parameters.
Experimental study on extreme ultraviolet light generation from high power laser-irradiated tin slab
Authors: Cai Yi  , Wang Wen-Tao  , Yang Ming  , Liu Jian-Sheng  , Lu Pei-Xiang  , Li Ru-Xin  , Xu Zhi-Zhan  ,   中国科学院上海光学精密机械研究所强场激光物理国家重点实验室，上海  201800
Published: December 2020

An experimental system has been set up for producing extreme ultraviolet light with high conversion efficiency by employing high power YAG laser irradiated tin slab. The dependence of extreme ultraviolet light intensity and conversion efficiency on the pump energy were studied， and the saturation effect of conversion efficiency was observed. The highest conversion efficiency of 1.6% in producing 13.5nm extreme ultraviolet light with 0.27nm bandwidth was achieved at pump energy of 250mJ, which corresponds to an intensity of 1.8×1011W/cm2.
Langmuir probe measurement and theoretical studies on inductively coupled plasma in Ar-N2 discharge
Authors: Gao Fei  , Mao Ming  , Ding Zhen-Feng  , Wang You-Nian  ,   大连理工大学物理与光电工程学院，三束材料改性国家重点实验室，大连  116024
Published: December 2020

In this article we use the Langmuir probe and kinetic model to study the electron energy distribution function (EEDF), the electron temperature, and the electronic density in the radio-frequency inductively coupled plasma of Ar-N2 discharge. It has been found that, with the increase of the N2 flow, the EEDF varies from the bi-temperature distribution to the tri-temperature distribution; the electron temperature drops monotonically at low pressures (pp>1.3 Pa). In addition, due to the recombination of electrons and nitrogen molecular ions, the electron density drops substantially at high pressures when a small amount of N2 is added to the gas mixture. Although the theoretically obtained electron temperature is high than the experimentally measured one, the theoretical model presents good predictions of the influences of N2 ratio in Ar-N2 mixture on the electron temperature and EEDF.
Investigation on surface damage phenomena induced by flashover across semiconductor
Authors: Zhao Wen-Bin  , Zhang Guan-Jun  , Yan Zhang  ,   西安交通大学电气工程学院，电力设备电气绝缘国家重点实验室，西安  710049
Published: December 2020

The flashover across semiconducting materials disables many high power semiconductor devices from their further application under high electric field. Up to now, the physical mechanism of the flashover was still not understood clearly. Surface flashover experiments of silicon and gallium arsenide were performed under pulsed high voltage. The filament current channels on their surface were observed in the infrared photographs, and the infrared radiation bright spot was found in the central region between the electrodes. On the surface of different samples undergone flashover events for several times, the filament damage phenomena were observed, and for the n100 silicon sample, some circular pits were found around the filament channel, with a conical jut in the center of each pit. According to the damage phenomena at the edge of electrodes, the thermal injection and relaxation characteristics of majority carriers were discussed. An injection model induced by minority carriers was proposed, which emphasizes the surface field enhancement by non-equilibrium carrier channel, which possibly leads to the ionization of the ambient gas above the filament channel. The model was consistent with the observed experimental results.
Lattice dynamics of single wall BC3 nanotubes
Authors: Wang Hui  , Feng Min  , Cao Xue-Wei  , Wang Yu-Fang  , Jin Qing-Hua  , Ding Da-Tong  , Lan Guo-Xiang  ,   南开大学物理科学学院，天津  300071
Published: December 2020

The structures of single wall BC3 nanotubes are described in the present paper. The symmetry and lattice dynamics of single wall BC3 nanotubes are analyzed in detail. Based on the force constant model we calculate the phonon dispersion relations of single wall BC3 nanotubes with different diameters and chiralities. For Raman and infrared active modes, the diameter-dependence of vibrational frequency has been established. It can be inferred that the Raman and infrared spectra of BC3 nanotubes would be more complex than those of single carbon nanotubes.
A study of damage evolution during annealing of helium-implanted magnesium-aluminate spinel
Authors: Yang Yi-Tao  , Zhang Chong-Hong  , Zhou Li-Hong  , Li Bing-Sheng  ,   (1)中国科学院近代物理研究所，兰州  730000; (2)中国科学院近代物理研究所，兰州  730000；中国科学院研究生院，北京  100049
Published: December 2020

Evolution of damage in single-crystalline magnesium-aluminate spinel implanted with helium ions was studied using Rutherford backscattering technique in channeling geometry combined with surface investigation by atomic force microscopy. It was found that the damage induced by helium-ion implantation in the crystal showed significantly different annealing behavior depending on the implantation fluence. The difference in annealing behavior is ascribed to the strong dose dependence of clustering/resolution of helium atoms.
Substrate temperature and B-doping effects on microstructure and electronic properties of p-type hydrogenated microcrystalline silicon films
Authors: Yang Shi-E  , Wen Li-Wei  , Chen Yong-Sheng  , Wang Chang-Zhou  , Gu Jin-Hua  , Gao Xiao-Yong  , Lu Jing-Xiao  ,   郑州大学物理工程学院，材料物理教育部重点实验室，郑州  450052
Published: December 2020

P-type hydrogenated microcrystalline silicon thin films have been prepared by radio-frequency plasma-enhanced chemical vapor deposition with B2H6 as a doping gas. The effects of substrate temperature and the doping ratio on the microstructure and dark conductivity of the p-type hydrogenated microcrystalline silicon films have been investigated. The results show that the films deposited at higher substrate temperature are amorphous even if the doping ratio is very low. The crystalline volume fraction of films monotonically decreases and the dark conductivity initially increases slowly and then decreases rapidly with substrate temperature increasing, which is very similar to the effects of the doping ratio. Finally the growth mechanism of p-type hydrogenated microcrystalline silicon thin films has been discussed in particular.
Effects of annealing of r-cut sapphire substrate on its surface morphology and the growth of CeO2 buffer layers and the Tl-2212 superconducting films
Authors: Xie Qing-Lian  , Yan Shao-Lin  , Zhao Xin-Jie  , Fang Lan  , Ji Lu  , Zhang Yu-Ting  , You Shi-Tou  , Li Jia-Lei  , Zhang Xu  , Zhou Tie-Ge  , Zuo Tao  , Yue Hong-Wei  ,   南开大学信息技术科学学院电子信息科学与技术系，天津  300071
Published: December 2020

In this study, the surface morphology evolution and the change of the phase structure of r-cut sapphire substrates annealed at different temperatures for different time in O2, and the effects of annealing conditions on the growth of CeO2 and Tl-2212 films, were investigated by AFM and XRD. The results of AFM show that the local steps on the substrate annealed at 1000℃ is formed firstly, and then the multilayer terrace-and-step structure, yielding from prolonging annealing time, evolves into wide terrace-and-step structure with ultrasmooth terrace through the coalition of initial localized steps, which slightly tilts to the surface. XRD measurements show that the CeO2 films prepared on r-cut sapphire annealed at the optimized conditions and the 500 nm thick Tl-2212 films grown on the CeO2 buffer layers subsequently possess excellent in-plane and out-of plane orientation, and the annealing temperature and annealing time have strong effect on the crystalline quality of substrates and CeO2 films. The Tl-2212 films have a high transition temperature (Tc=104.7 K), a high critical current density (Jc=3.5 MA/cm2 at 77.3K and zero applied magnetic field) and a low surface resistance (Rs=390μΩ at 10GHz and 77K).
Radiation degradation model of metal-oxide-semiconductor field effect transistor based on pre-irradiation 1/f noise
Authors: Peng Shao-Quan  , Du Lei  , Zhuang Yi-Qi  , Bao Jun-Lin  , He Liang  , Chen Wei-Hua  ,   (1)西安电子科技大学技术物理学院，西安  710071; (2)西安电子科技大学微电子学院，西安  710071
Published: December 2020

Based on metal-oxide-semiconductor field effect transistor (MOSFET) noise theory of carrier number fluctuation and mobility fluctuation， a quantitative mathematic model between pre-irradiation 1/f noise parameters and post-irradiation threshold voltage drift due to oxide traps and interface traps is established. It agrees well with the experimental results. This model shows that 1/f noise in MOSFET is priginates from the random trapping/detrapping processes between oxide traps and the channel， which causes fluctuations in both the number and the mobility of channel carriers. So pre-irradiation 1/f noise magnitude is directly proportional to post-irradiation oxide-trap charge. The results not only explain the correlation between MOSFET pre-irradiation 1/f noise power spectral density and radiation degradation in theory， but also provide the theory for forecasting MOSFET radiation-resistant capability.
Effect of substrate constraint on stress-induced cracking of sputtered tungsten thin film
Authors: Sun Hao-Liang  , Song Zhong-Xiao  , Xu Ke-Wei  ,   西安交通大学金属材料强度国家重点实验室，西安  710049
Published: December 2020

A comparative investigation was performed on the stress-induced surface cracking of tungsten films sputter deposited on polyimide (PI) and Si substrates. Microscopic observations suggest that with the same film thickness， two different types of cracking behaviors were observed. Wedge-shaped cracks are formed on the surface of film deposited on the Si substrate. However， the cracks of film deposited on the polyimide consist of aligned grains. The localized plastic deformation in the nanocrystalline W film on polyimide is mediated by the alignment of grains， which results from the grain rotation along the in-plane and out-of-plane directions. However， on the Si substrates the wedge-shaped cracks originate from the in-plane rotation of grains. The analysis implies that the different deformation behaviors are associated with the evolution of stress in the film and the substrate constraint.
Influence of low rate p/i interface layer on the performance of high growth rate microcrystalline silicon solar cells
Authors: Han Xiao-Yan  , Hou Guo-Fu  , Li Gui-Jun  , Zhang Xiao-Dan  , Yuan Yu-Jie  , Zhang De-Kun  , Chen Xin-Liang  , Wei Chang-Chun  , Sun Jian  , Geng Xin-Hua  ,   南开大学光电子薄膜器件与技术研究所，光电子薄膜器件与技术天津市重点实验室，光电信息技术科学教育部重点实验室，天津  300071
Published: December 2020

In the process of the high growth rate μc-Si：H film deposited by very high frequency plasma enhanced chemical vapor deposition (VHF-PECVD)， the high energy ion impinging on the growing surface could deteriorate the device performance. Incorporation of a low growth rate intrinsic μc-Si：H p/i buffer layer was advanced in this paper. The results show that the introduced low growth rate buffer layer could improve the characteristics of p/i interface and the vertical uniformity of the intrinsic layer. It was found that the defects in intrinsic layer first decreased and then increased with increasing thickness of the buffer layer. These results led to an optimal thickness for the buffer layers. The efficiency of solar cells was increased about 1% when the thickness was optimized. As a result， the efficiency of 8.11% has been achieved at an i-layer deposition rate of 8.5nm/s.
Study on the flatband potential of nanoporous TiO2 film electrode
Authors: Dai Jun  , Hu Lin-Hua  , Liu Wei-Qing  , Dai Song-Yuan  ,   中国科学院等离子体物理研究所，合肥  230031
Published: December 2020

The flatband potential of nanoporous TiO2 film electrodes has been studied by spectroelectrochemical method. The effect of film thickness and TiCl4 treatment on the flatband potential of nanoporous TiO2 electrodes and the photovoltaic performance of dye-sensitized solar cells were determined. The results showed that with the increasing of film thickness， the flatband potential shifts in the positive direction， and the open circuit voltage of corresponding solar cells decreases. In addition， after TiCl4 treatment， the flatband potential and the open circuit voltage of corresponding solar cells were not obviously changed. All this suggests that the flatband potential of nanoporous TiO2 electrode can reflect the changing trend of open circuit voltage of solar cells well.
Effects of eddy current on surface retarded modes of a lateral antiferromagnetic/nonmagnetic superlattice
Authors: Lei Wei-Ping  , Jia Cheng  , Wang Xuan-Zhang  ,   哈尔滨师范大学物理系，哈尔滨  150080
Published: December 2020

Using the equivalent medium theory, we have investigate the surface retarded modes of a semi-infinite lateral superlattices composed of semiconductor antiferromagnetic layers and insulating nonmagnetic layers in the Voigt geometry. We studied the effect of eddy current on surface retarded modes of a lateral antiferromagnetic/nonmagnetic superlattice when the external field is zero or nonzero. Particularly, we have considered the effect of conduction current and displacement current on the retarded modes, and have obtained for the first time the curves for different cases of the frequency and the spin wave damping versus the wave vector k.
Investigation on the fuzzy recognition mechanism for γ-ray fingerprints of nuclear materials
Authors: Wang Chong-Jie  , Bao Dong-Min  , Cheng Song  , Zhang Ai-Lian  ,   (1)辽宁师范大学分析测试中心，大连  116029; (2)辽宁师范大学物理与电子技术学院，大连  116029
Published: December 2020

Within the scope of the two_dimensional space with the energy and intensity of γ-ray as coordinates, we brought forward the concept of the two_dimensional fuzzy set about spectra, and established the membership function. We also introduced the fundamental principles and method for identifying the γ-ray fingerprints by fuzzy recognition technique. By regularizing the spectra, we succeeded in identifying the types and individuals of nuclear materials. Further more, we introduced the multiplying factor, and thus obtained high degree of confidence in identifying the spectra. We identified the simulation materials as radiation sources with the method, and studied the influence of the detecting distance and the detecting system fluctuation on the membership degree. The results show that the method has strong capabilities of identifying the types and the individuals of radiation sources, and can be applied to the nuclear materials safeguard.
The periodic solutions of El Nino mechanism of atmospheric physics
Authors: Li Xiao-Jing  ,   江苏技术师范学院数理学院，常州  213015；安徽师范大学数学计算机科学学院，芜湖  241000
Published: December 2020

Using Mawhin’s continuation theorem,the periodic solutions for a class of nonlinear problem are first discussed.An El Nio atmospheric physicsal mechanism is applied and the periodic solutions for its model are obtained.
Analysis of Hamaker continuum mediun hypothesis
Authors: Tian Wen-Chao  , Jia Jian-Yuan  ,   西安电子科技大学机电工程学院，西安  710071
Published: December 2020

The three Hamaker hypotheses are the basic principle of the micro-continuum medium. On the basis of the actual crystalline structure, the problem that, the Hamaker idea of continuum medium may not hold is discovered. There are gaps among the crystal structures. In order the micro-object to be a continuum, a close-packed Wigner-Seitz model is put forward by the object structure principle. By analysis of the double Wigner-Seitz model and the classic Lennard-Jones potential, the Hamaker medium amendatory factors for fcc and bcc are derived. The Hamaker additivity hypothesis and homogeneous hypothesis are revised. The micro-continuum medium form including the repulsive force is revised too. The application area of the micro-continuum medium is extended from the attractive force to the repulsive force, which provids an approach to the practical problems in engineering.
Homoclinic bifurcation of the strongly nonlinear oscillation system by the normal form method
Authors: Zhang Qi-Chang  , Wang Wei  , He Xue-Jun  ,   天津大学机械学院力学系，天津  300072
Published: December 2020

The available range of the homoclinic bifurcation criterions are extended from the weakly nonlinear oscillation system to the strongly nonlinear oscillation system. It combines the analysis method of the strongly nonlinear oscillation system with the former criterions based on the improved complex normal form method. The periodic solution of this kind of system with a single degree of freedom is obtained by introducing the fundamental frequency under determination into the complex normal form computation. Then two different analytical criteria to predict the critical values of homoclinic bifurcation are adapted to the new system. It includes the undertermined fundamental frequency approaching zero and the collision of the periodic orbit with the saddle point. The results derived from different methods are compared in the specific systems with numerical simulation to testify the correctness and efficiency of the theoretical results.
A new fractional-order hyperchaotic system and it’s chaotic synchronization
Authors: Zhou Ping  , Cheng Xue-Feng  , Zhang Nian-Ying  ,   重庆邮电大学应用物理研究所，重庆  400065；重庆邮电大学非线性系统研究所，重庆  400065
Published: December 2020

A new fractional-order hyperchaotic system is reported. A synchronization method for the new chaotic systems is established and its mathematical proof is provided. The nonlinear terms in the response system are not dropped.The good agreement between theoretical analysis and numerical simulation shows the efficiency of the method.
Magnetic and electrical properties of layered perovskite La1.3Sr1.7Mn1-xCuxO7
Authors: Han Li-An  , Chen Chang-Le  , Dong Hui-Ying  , Wang Jian-Yuan  , Gao Guo-Mian  , Luo Bing-Cheng  ,   西北工业大学陕西省凝聚态结构与性质重点实验室，西安  710072
Published: December 2020

Magnetic and electrical properties of polycrystalline La1.3Sr1.7Mn2-xCuxO7 prepared by solid state reaction were investigated. The X-ray diffraction pattern shows that the two samples have Sr3Ti2O7 type perovskite structure. The two samples undergo complex transition with lowering temperature. The x=0 samples, have the two-dimensional short-range ferromagnetic order at T*=231 K and then transform to the three-dimensional long-rangs ferromagnetic state at TC=114 K, at last they enter the canted antiferromagnetic state at TN=56K. The T*, TC and TN are all reduced at the 5% Cu doping level. Additionally, the two samples exhibited two distinct resistivity peaks, which is due to coexistence of the two phases. The metal-insulator transition temperature was decreased but the magnetoresistance was enhanced at the 5% Cu doping level.
The calculation of terahertz wave power radiated from GaAs photoconductive antenna
Authors: Jia Wan-Li  , Shi Wei  , Qu Guang-Hui  , Sun Xiao-Fang  ,   西安理工大学理学院应用物理系，西安  710048
Published: December 2020

Based on the Larmor formula, a mathematic model is established to calculate the power of THz wave radiated form the photoconductive antenna. The power of THz waves radiated by GaAs photoconductive antenna under different experimental conditions was calculated by Monte Carlo simulations. The results show that the power of THz radiation can be improved by increasing the bias electric field or the energy of triggering light pulse, and large-aperture photoconductive antenna can emit THz wave with higher power compared with photoconductive antennas with small apertures because the former can carry more photo-generated carriers.
Conversion cross section between photon and axion in external electromagnetic field
Authors: Wang Ping  , Li Fang-Yu  , He Xiao-Yu  ,   重庆大学物理系，重庆  400044
Published: December 2020

We calculate the unpolarized differential cross section in magnetic dipole field, electric dipole field and uniform electrostatic and magnetostatic fields, respectively,by the Feynman perturbation technique. It is found that in electric dipole field, the differential cross section vanishes in both the same and the opposite propagating directions of the photon flux. In the magnetic dipole field the differential cross section generally has non-vanishing values in both directions,but when the propagating direction of photon flux is parallel to the magnetic dipole vector, the differential cross section is equal to zero. In the uniform electrostatic and magnetostatic fields, non-vanishing differential cross sections occur in the same and opposite propagating directions of the photon flux, but in the latter case it is weaker than in the former. When the mass of axion approaches to zero,the above process shows similar characters as the conversion of the photons to the gravitons.
Analysis of the experiment data of vertical migration of radon and its daughters under ideal conditions
Authors: Tan Yan-Liang  , Xiao De-Tao  , Zhao Gui-Zhi  ,   (1)南华大学核科学技术学院,衡阳  421001; (2)南华大学核科学技术学院,衡阳  421001；衡阳师范学院物电系,衡阳  421008
Published: December 2020

We analyzed the vertical long distance migration experiment data of radon and its daughters,and found that the number of α particles is insufficient to explain the fast upward migration of radon by helium- radon clustering. If assume that radon has very strong ability to adsorb the helium from the air to form helium-radon clusters for vertical migration, then there is an inconsistency between the tentative and that experimental conclusion,that the upward and downward migration probability of radon and its daughters in natural state is equal to that when helium gas is added.So we propose that helium- radon clustering may not be the main reason of radon and its daughters′ fast upward migration. There may be other more complex reasons. The phenomenon needs further research.
Structures and magnetism of BnNi(n=6—12) clusters from density-functional theory
Authors: Lei Xue-Ling  , Zhu Heng-Jiang  , Ge Gui-Xian  , Wang Xian-Ming  , Luo You-Hua  ,   (1)华东理工大学理学院，上海  200237；河南大学物理与电子学院，开封  475004; (2)石河子大学师范学院物理系，石河子  832003; (3)新疆师范大学数理信息学院，乌鲁木齐  830054
Published: December 2020

Based on the first-principle, all geometric structures of Bn and BnNi clusters with n=6—12 have been optimized by using density functional theory with generalized gradient approximation, the equilibrium geometries for different spin multiplicities and ground-state structures have been determined. The results of Bn clusters are in good agreement with previous conclusions. When the Ni atom is doped in Bn clusters, the ground-state structure of the BnNi clusters favor three dimensional, but B12Ni cluster has the planar structure. The spin multiplicity of ground-state structures, except for n=8, obey the 2 and 1 alternate rule. The average atomic binding energies (Eb), second-order energy differences (Δ2E) and the HOMO-LUMO (gap) of ground-state structures have been calculated and discussed. The results indicated that n= 8 is the magic number of BnNi(n=6—12) clusters, implying that B8Ni cluster possess relatively higher stability. Calculated results on the magnetic moments show that the magnetic moment of B8Ni cluster is the biggest (2μB), the total magnetic moment and the average magnetic moment of clusters show the odd-even oscillation tendency along with the size increasing, and the magnetic moment is mainly provided by the 3 d orbital of Ni atom.
Composite optical vortices formed by two flattened Gaussian vortex beams and their propagation in free space
Authors: Yan Hong-Wei  , Cheng Ke  , Lü Bai-Da  ,   四川大学激光物理与化学研究所，成都  610064
Published: December 2020

The composite optical vortices (OVs) in the superimposed field of two parallel, off-axis flattened Gaussian vortex beams with topological charge m1, 2=±1 at the waist plane and their propagation dynamics in free space are studied. Detailed numerical calculations and analysis show that the number, position and net topological charge of composite OVs depend on the control parameter, such as the relative phase, amplitude ratio, waist-width ratio, relative off-axis distance, beam order, and on the propagation distance, but the topological charge is not always conserved.
The spatial energy distribution and the spectrum characteristics in a two-dimensional random medium
Authors: Wang Hui-Qin  , Liu Zheng-Dong  , Wang Bing  ,   (1)南昌大学材料科学与工程学院，南昌  330031；南昌大学纳米技术研究中心，南昌  330047; (2)南昌大学材料科学与工程学院，南昌  330031；南昌大学物理实验中心，南昌  330031; (3)南昌大学纳米技术研究中心，南昌  330047
Published: December 2020

The spatial distributions of energy in a random medium and the spectrum characteristics of some regions in this medium are studied and the results show that the energy is localized in some regions and the spatial distribution of the energy is both related with positions of the particles in the medium and the wavelength of excitation light. And the regions of energy congregation are related with the quasi-closed structures formed from the particles but no one to one correspondence exists between them. Under the stimulating of the same excitation light, different spectra appear in different quasi-closed structures and they change with time. And under the stimulating of different excitation light sources, the spectra of the same quasi-closed structure are different. When the wavelength of exci tation light does not match the configuration parameter of a quasi-closed structure, the peaks of its spectrum will change frequently and the energies of the peaks are attenuated quickly. When the wavelength of the light be ther matches the configuration parameter of the quasi-closed structure, a certain peak will retain its leading position in height in the spectrums and its energy attenuate but slowly. So photon-localization is both related with the configuration of medium and the wavelength of excitation light, and the random lasing can be regarded as the result of the general scattering effect of the excitation light by the random medium.
Study on the morphology of laser induced damage in K9 glass by focused nanosecond pulse
Authors: Han Jing-Hua  , Feng Guo-Ying  , Yang Li-Ming  , Zhang Qiu-Hui  , Xie Xu-Dong  , Zhu Qi-Hua  , Zhou Shou-Huan  ,   (1)四川大学电子信息学院，成都  610064; (2)四川大学电子信息学院，成都  610064；华北光电技术研究所，北京  100015; (3)四川大学电子信息学院，成都  610064；中国工程物理研究院激光聚变研究中心，绵阳  621900; (4)中国工程物理研究院激光聚变研究中心，绵阳  621900
Published: December 2020

The characteristics of laser induced damage morphology in the bulk of the K9 glass caused by focused nanosecond laser pulse is analyzed in detail. The damage shape looks like a spindle with a large front-end and its thickness gradually decreases on going to the rear end. According to the experimental results, the damaged range can be divided into four zones, namely the filamentary plasma channel, fractures, the fusion zone and the region of varying refractive index. The function of laser pulse energy deposition in space and the expansion pressure of shock wave are deduced, and the corresponding damage morphology is analyzed based on the spatial distribution of pressure. The theoretical analysis agrees with the experimental results.
Photon emission of a two-level atom passing through double single-mode cavity fields
Authors: Sun Yu-Hang  , Xi Xiao-Qiang  ,   西安邮电学院应用数理系，西安  710121
Published: December 2020

A two-level atom passing through double spatially separated single-mode cavity fields is studied. We investigate the effecting factors of photon emission probabilities of the atom, which include the kinetic energy of the atom, the length of the cavity and the separation between the two cavities. The results show that in the case of ultra-cold atom, when the kinetic energy of the atom is small (k/k0k/k0>1), the length of the cavity has great effect on the photon emission probabilities. The present work shows that the photon emission probabilities may be modulated by controlling the center-of-mass motion of the atom.
Growth kinetics and microstructure characterization of oxide film formed on La-implanted Co-Cr alloy
Authors: Jin Hui-Ming  , Felix Adriana  , Aroyave Majorri  ,   (1)国立安第克大学材料科学与工程学院,哥伦比亚 麦德林  23715; (2)扬州大学机械工程学院,扬州  225009
Published: December 2020

The isothermal and cyclic oxidizing kinetics of Co-40Cr alloy and its lanthanum ion-implanted samples were studied at 1000℃ in air by thermal-gravimetric analysis (TGA). Scanning electronic microscopy (SEM) and transmission electronic microscopy (TEM) were used to examine the morphology and structure of the oxide film after oxidation. Secondary ion mass spectrum (SIMS) method was used to examine the binding energy change of chromium caused by La-doping and its influence on formation of Cr2O3 film. Laser Raman spectrum was used to examine the stress changes within oxide films. It was found that lanthanum implantation remarkably reduces the isothermal oxidizing rate of Co-40Cr and improves the anti-cracking and anti-spalling properties of Cr2O3 oxide film. The reasons for the improvement were mainly that the implanted lanthanum reduces the grain size and internal stress of Cr2O3 oxide and increases the high temperature plasticity of oxide film. Lanthanum mainly exists in the outer surface of Cr2O3 oxide film in the forms of fine La2O3 and LaCrO3 spinel particles.
Experimental study of coherent beam combining of two fiber lasers
Authors: Wang Jian-Ming  , Duan Kai-Liang  , Wang Yi-Shan  ,   (1)中国科学院西安光学精密机械研究所瞬态光学与光子技术国家重点实验室,西安  710119; (2)中国科学院西安光学精密机械研究所瞬态光学与光子技术国家重点实验室,西安  710119；中国科学院研究生院,北京  100049
Published: December 2020

The phase-locking of two photonic crystal fiber (PCF) lasers is studied experimentally by using Michelson cavity technique, and 47 W coherent output power is obtained. The phenomenon of interference-enhancement and interference-loss on the two arms of the Michelson cavity is theoretically explained by analyzing the optical path difference. Experiment shows that the Michelson cavity setup can improve the spectra of the combined laser significantly. The bandwidth of the combined laser is less than 5nm in our experiment.
Theoretical research on InnoSlab output beam quality with hybrid resonator
Authors: Wang Ning  , Lu Yu-Tian  , Li Xiao-Li  , Jiao Zhi-Yong  ,   (1)中国科学院上海光学精密机械研究所，上海  201800; (2)中国石油大学(华东)物理科学与技术学院，东营  257061
Published: December 2020

Output beam quality of InnoSlab laser with hybrid resonator is analyzed in this paper for the thermal lens effect and mirror misalignment. Many aspects, such as far-field light intensity distribution, far-field divergence angle, beam waist radius, beam quality factor M2 and PIB curve, etc, are discussed. Especially, in the off-axis unstable resonator direction, the influence of beam quality is discussed with respect to mirror misalignment by M2 and PIB curve. This gives valuable reference to unstable resonator beam quality evaluation, for which a unified standard has not been set up as yet.
Switching in three-core nonlinear fiber coupler with second order coupling dispersion coefficient
Authors: Li Qi-Liang  , Xie Yu-Yong  , Zhu Yin-Fang  , Zhao Zhi-Jin  , Wang Tian-Shu  , Qian Sheng  , Lin Li-Bin  ,   (1)杭州电子科技大学通信工程学院通信与信息系统研究所，杭州  310018; (2)四川大学物理系，成都  610064
Published: December 2020

The propagation and switching of fundamental solitons in three-core fiber nonlinear directional coupler with three cores in an equilateral-triangle arrangement have been investigated with two methods. Firstly, by using variational method, we obtained the　equation of transmission coefficient with respect to distance. Secondly, we used the split-step Fourier method (SSFM) to solve the nonlinear Schrdinger equations. The results of both variational method and SSFM indicate that the energy of optical pulses transfer periodically between the three cores and have sharp switching characteristics when the first order intermodal dispersion coefficient is small. Otherwise, the periodicity of the coupling transmission characteristics of optical solitons in fiber coupler and the sharpness of switching are destroyed. The second order intermodal dispersion coefficient and initiative chirp reduce the coupling length, shorten the periods of the energy transfer of optical pulses between the three cores, and increase the threshold switching power. Though the cross phase modulation coefficient has weaker impact on transmission characteristics, it increases the threshold switching power of couplers.
Chromatic bistability and luminescence switching of visible-infrared emission in Tm-doped laser crystal
Authors: Li Li  , Zhang Xin-Lu  , Chen Li-Xue  , Wang Ran  ,   (1)哈尔滨工程大学理学院，哈尔滨  150001; (2)哈尔滨工业大学物理系，哈尔滨  150001; (3)哈尔滨工业大学物理系，哈尔滨  150001；哈尔滨工程大学理学院，哈尔滨  150001
Published: December 2020

Optical bistability and luminescence switching of visible-infrared emission in Tm-doped laser crystal pumped at 648nm avalanche wavelength is predicted theoretically and studied numerically. The analytical formula of luminescence switching threshold is deduced using the theory of nonlinear rate equations. The evolutions of populations of Tm3+ energy levels, emission spectrum and fluorescence intensity versus pump power are investigated numerically. The numerical results predict that the luminescence switching between 452/469nm blue and 1716nm infrared spectra can be experimentally realized under 648nm laser pumping. Moreover, the bistability of emission spectra, chromatic fluorescence and luminescence intensity in Tm-doped crystal can be observed in the vicinity of photon avalanche threshold. The characteristics of chromatic bistability and luminescence switching in Tm-doped crystal allow for the tailoring of pump-controlled all-solid luminescent switcher and bistable wavelength switch operating in visible-infrared spectral range.
Slow wave effect of 2-D photonic crystal coupled cavity array
Authors: Du Xiao-Yu  , Zheng Wan-Hua  , Ren Gang  , Wang Ke  , Xing Ming-Xin  , Chen Liang-Hui  ,   中国科学院半导体研究所纳米光电子实验室,北京  100083
Published: December 2020

We designed a two-dimensional coupled photonic crystal resonator array with hexagonal lattice. The calculation by plane-wave-expansion method shows that the dispersion curve of coupled cavity modes in the bandgap are much flattened in all directions in the reciprocal space. We simulated the transmission spectra of transverse electric(TE) wave along the ΓK direction. Compared with the PC single cavity structure, the transmission ratio of the coupled cavity array increases more than three orders of magnitude, while the group velocity decreases to below 1/10, reaching 0.007c. The slow wave effect has potential application in the field of miniaturized tunable optical delay components and low-threshold photonic crystal lasers.
Magnetron photonic switching circuit in photonic crystal
Authors: Bi Hai-Xing  , Zhou Yun-Song  , Zhao Li-Ming  , Wang Fu-He  ,   首都师范大学物理系，北京  100037
Published: December 2020

We proposed a theoretical model of magnetron photonic switching circuit (MPSC) in photonic crystal (PC) and investigated the properties of MPSC using the plane wave expansion method in combination with supercell method. This model is a PC composed of dielectric pillars set in air, in which one row of dielectric pillars is replaced by ferrite material with the dielectric constant same as that of the original dielectric pillars. When external static magnetic field is applied, the permeability of the ferrite pillars will not be equal to one and guide modes along the row of ferrite pillars may be generated in band gap. When the external field is removed, this system reverts to a perfect PC. Thus, this system forms a photonic switching circuit controlled by the external field. In calculation, we take square pillars set in square lattice. The calculation results show that this MPSC is reasonable and realizable, and some valuable results are obtained.
The effect of alignment precision in neutron penumbral imaging
Authors: Zhao Zong-Qing  , Ding Yong-Kun  , Hao Yi-Dan  , Yuan Yong-Teng  , Pu Yi-Kang  ,   (1)清华大学工程物理系，北京  100084; (2)中国工程物理研究院激光聚变研究中心，绵阳  621900; (3)中国工程物理研究院激光聚变研究中心，绵阳  621900；清华大学工程物理系，北京  100084
Published: December 2020

Based on Monte Carlo simulation of neutron penumbral imaging，the linear space invariance is researched. In the field of view，the points broadening linearly depends on the axial distance on the object plane，but the integrated intensity keeps linear space invariance. Using this result，the alignment precision is analyzed. The axial error of the targets center on the object plane should be controlled within 50μm. The point source should be less than 300μm away from the object plane. The aperture rotation should be within 0.1mrad.
Experimental investigation of square superlattice pattern formation in a dielectric barrier discharge
Authors: Dong Li-Fang  , Zhao Hai-Tao  , Xie Wei-Xia  , Wang Hong-Fang  , Liu Wei-Li  , Fan Wei-Li  , Xiao Hong  ,   河北大学物理科学与技术学院，保定  071002
Published: December 2020

The formation of the square superlattice pattern in discharge in the mixture of argon and air is investigated by using a dielectric barrier discharge device with water electrode. It is found that the bifurcation process of the patterns follows goes through the stages of square pattern，quasisuperlattice pattern，square superlattice pattern and the stripe or hexagonal pattern. Their spatial Fourier spectra are analyzed and the variation of the wave vector as a function of the applied voltage is determined. In addition，two types of square superlattice patterns with different spatial scales are observed with the applied voltage increasing. They all satisfy the standing wave condition. The role of wall charge accumulated in the dielectric layers in the formation of the square superlattice pattern is analyzed. Both the phase diagram on the plot of pattern type against the gas gap width and applied voltage and the phase diagram on the plot of the square superlattice pattern against the gas gap width and the gas pressure are obtained. In addition，the changes of the breakdown voltage and the voltage of the square superlattice pattern as a function of the air concentration are determined. It is found that they increase with the increasing of the air concentration.
Microscopic defects in Ti-Mo alloy hydrides studied by small-angle X-ray scattering
Authors: Du Xiao-Ming  , Wu Er-Dong  , Dong Bao-Zhong  , Wu Zhong-Hua  , Yuan Xue-Zhong  ,   (1)沈阳理工大学材料科学与工程学院，沈阳  110168；中国科学院金属研究所沈阳材料科学国家(联合)实验室，沈阳  110016; (2)中国科学院高能物理研究所同步辐射国家实验室，北京  100049; (3)中国科学院金属研究所沈阳材料科学国家(联合)实验室，沈阳  110016; (4)中国科学院金属研究所沈阳材料科学国家(联合)实验室，沈阳  110016；沈阳建筑大学理学院，沈阳  110168
Published: December 2020

In this work，the microscopic defects in Ti-Mo alloy hydrides were studied by using small-angle X-ray scattering (SAXS) technique. The results show that the SAXS intensity measured for hydride of 5at％ Mo alloy was lower than that of other hydrides in the high scattering angle range. The crystal grains and its internal sub-structures in the hydrides are the scatterers which cause SAXS. The sub-structures are induced by the large number of dislocations in the hydrides produced during hydrogenation. The crystal structure of Mo 5at％ alloy is mainly hcp，but that of the other alloys is bcc. The hydrides of all these alloys, however, have a fcc crystal structure. Therefore，it is indicated that the Ti-Mo alloys with hcp and bcc crystal structures form the same hydride structure，but induce different types of dislocation defects during hydrogenation.
SAXS and XRD studies on the microstructure of TiO2 nanoparticles
Authors: Chen Zhong-Jun  , Wang Wei  , Cai Quan  , Chen Xing  , Wu Zhong-Hua  , Li Rong-Ping  , Che Chuan-Qiang  , Pan Wei  ,   (1)江西省计量测试研究院，南昌  330002; (2)内蒙古大学理工学院，呼和浩特  010021; (3)中国科学院高能物理研究所同步辐射室，北京  100049
Published: December 2020

TiO2 nanoparticles were prepared by sol-gel method，and were annealed at different temperatures from 300 to 800℃. Their interfacial and fractal characteristics as well as and phase transition were investigated by using synchrotron radiation SAXS and XRD techniques. The change of nanoparticle size with annealing temperature was determined. The relationship between the interfacial characteristics and phase transition was discussed in this paper.
Investigation of the controllable growth of the TiO2 nanotube arrays fabricated by anodic oxidation method
Authors: Wang Cheng-Wei  , Ma Bao-Hong  , Li Yan  , Chen Jian-Biao  , Wang Jian  , Liu Wei-Min  ,   (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；中国科学院兰州化学物理研究所固体润滑国家重点实验室，兰州  730000; (3)中国科学院兰州化学物理研究所固体润滑国家重点实验室，兰州  730000
Published: December 2020

The highly ordered and uniform TiO2 nanotube arrays were fabricated by anodic oxidation of titanium foil in HF aqueous solution or ethylene glycol containing NH4F and deionized water. The diameter，density，length and wall thickness of nanotube arrays can be controlled effectively by varying the anodization parameters including electrolyte composition，voltage，and time. The microstructures of the titania nanotube arrays were characterized by X-ray diffraction (XRD). The results showed that the as-anodized titania nanotubes were amorphous. And when annealed in vacuum or in oxygen ambient at 500℃，the samples prepared in HF aqueous solution showed only anatase phase，and the samples prepared in ethylene glycol containing NH4F and deionized water showed both anatase and rutile phases. And the former and the latter batch of samples became better crystallized when annealed in oxygen and in vacuum，respectively. Furthermore，the controllable growth mechanism of nanotube arrays is discussed.
Luminescence and energy transfer of Eu2+, Mn2+ in BaZnP2O7
Authors: Yang Zhi-Ping  , Yang Guang-Wei  , Wang Shao-Li  , Tian Jing  , Li Pan-Lai  , Li Xu  ,   (1)河北大学电子信息工程学院，保定  071002; (2)河北大学物理科学与技术学院，保定  071002
Published: December 2020

The BaZnP2O7:Eu2+, Mn2+ phosphor was synthesized by high temperature solid state reaction. The luminescence properties and the energy transfer between Eu2+ and Mn2+ were investigated. The emission bands of Eu2+ and Mn2+ peaking at 380nm and 670nm were originated from 5d—4f transition of Eu2+ which partly substituted the Ba2+ sites and 4T1(4G)—6A1(6S) transition of Mn2+ occupying Zn2+ sites, respectively. The dependence of Eu2+ and Mn2+ luminescence properties on their concentration was investigated. With the increasing Mn2+ dopant content, the intensity of Eu2+ was observed to decrease, but the intensity of Mn2+ was simultaneously found to increase. It is suggested from this phenomenon that Mn2+ ion is sensitized by Eu2+ ion, in other words, there is an energy transfer from Eu2+ to Mn2+ in BaZnP2O7 host. According to the Dexter's energy transfer formula of multipolar interaction, we have demonstrated that the energy transfer between Eu2+ and Mn2+ is due to the electric dipole-quadripole interaction of the resonance transfer.
Molecular dynamics simulation of multi-wall carbon nanotube oscillators
Authors: Xie Fang  , Zhu Ya-Bo  , Zhang Zhao-Hui  , Zhang Lin  ,   (1)徐州师范大学物理与电子工程学院，徐州  221116; (2)中国矿业大学材料科学与工程学院，徐州  221008; (3)中国矿业大学材料科学与工程学院，徐州  221008；徐州师范大学物理与电子工程学院，徐州  221116; (4)中国矿业大学理学院，徐州  221008
Published: December 2020

Molecular dynamics simulations have been used to study the three kinds of multi-wall nanotube oscillators. The results show that the shorter the inner tube of the oscillators，the larger the oscillation frequency，and the fluctuations ofthe axial force acted on the inter tube are also larger. The inner tube rotatesabout the tube axis while oscillating along the tube axis. The rotational kinetic energy is fluctuating and closely related to the length of the inner tube. The study results can be used in developing new technology of producing carbon nanotubes.
Direct generation of isolated sub-50 attosecond pulse via controlling quantum paths by a low frequency field
Authors: Hong Wei-Yi  , Yang Zhen-Yu  , Lan Peng-Fei  , Lu Pei-Xiang  ,   武汉光电国家实验室，华中科技大学，武汉  430074
Published: December 2020

We propose a new method to directly generate an isolated sub-50 attosecond pulse. The combination of a 5fs driving laser pulse with the wavelength of 800nm and a low frequency field with the wavelength of 10μm is adopted. The intensity of the low frequency field is 10% that of the driving pulse. It is shown that the harmonic spectrum is extended to Ip+8.2Up and the harmonics above Ip+4.2Up become continuous. By adjusting the phase of the carrier-envelope of the few-cycle pulse，the bandwidth of the supercontinuum can be further broadened and a close-to-Fourier-limit sub-50as pulse is directly obtained.
A genetic algorithm research on Lorentz oscillator model in infrared spectra of GaMnN
Authors: Cheng Xing-Hua  , Tang Long-Gu  , Chen Zhi-Tao  , Gong Min  , Yu Tong-Jun  , Zhang Guo-Yi  , Shi Rui-Ying  ,   (1)北京大学宽禁带半导体研究中心，北京大学物理学院，北京  100871; (2)四川大学物理科学与技术学院微电子学系，成都  610064; (3)四川大学物理科学与技术学院微电子学系，成都  610064；微电子技术四川省重点实验室，成都  610064
Published: December 2020

The lattice vibrations of diluted magnetic semiconductor GaMnN epitaxial films grown on sapphire substrates by metalorganic chemical vapor deposition have been investigated using infrared reflectance spectroscopy. The revised genetic algorithm was successfully used to extract the Lorentz oscillator model parameters of GaMnN from infrared reflectance spectra. Comparing the Lorentz oscillator model parameters of GaMnN with those of GaN, it was found that ωTO moved to higher frequencies, γ, ε∞ and εs increased, but the ωLO was almost not changed. The effects of Mn on the properties of lattice vibration and the mechanisms of variations of the dielectric function were also analyzed and discussed in this paper.
Optimization of the electrode shape of AlGaInP LED
Authors: Zhang Jun-Bing  , Lin Yue-Ming  , Bo Lin  , Zeng Xiang-Hua  ,   (1)扬州大学物理科学与技术学院,扬州  225002; (2)扬州华夏集成光电有限公司,扬州  225009
Published: December 2020

The distribution of current diffusion of the quaternary AlGaInP LED has been simulated by finite element method to study the effect of electrode shape on the current spreading layer GaP. By comparing traditional circular-shape with cross-shape, arrow-shape, floriated-shape and gammadion-shape electrodes, we found that the electrode shape has an important effect on the output efficiency of light, and the light extraction efficiency of gammadion electrode is the highest. As the area of the whole electrode has an effect on the output efficiency, by optimizing the width of the electrode, the light extraction efficiency will be upgraded. For the gammadion electrode, when the width equals to 6.2204 μm, its light extraction efficiency is the highest, which is more than twice that of the traditional round electrode’s.