bluuebunny/crossref_metadata_2025 huggingface dataset:
Large intragranular low field magnetoresistance in polycrystalline Sr2Fe1－xAlxMoO6 compounds
Authors: Wang Xian-Jie  , Sui Yu  , Qian Zheng-Nan  , Cheng Jin-Guang  , Liu Zhi-Guo  , Li Yan  , Su Wen-Hui  , Ong C. K.  ,   (1)哈尔滨工业大学理学院凝聚态科学与技术研究中心，哈尔滨  150001; (2)新加坡国立大学物理系超导与磁性材料研究中心，新加坡  117542
Published: December 2020

Polycrystalline powders of the family of compounds Sr2Fe1-xAl xMoO6 (x=0, 005, 010, 015, 030) were prepared according to the standard solid_state reaction . XRD patterns and SEM images show that the structure and the grain size of these compounds were not changed and no imp urity was observed by doping with Al in Sr2FeMoO6. In the cationic ordered s egregation, a large ferrimagnetic patch can be separated into some smaller ones by the Al doping. So the chain of the ferrimagnetic exchange path will be short ened and the strength of exchange will be weakened. Therefore, their moments bec ome more sensitive to external field. Furthermore, when the Al ion replaces the Fe ion in the disordered segregation, the antiferromagnetic coupling becomes wea ker. As a result, the low_field magnetoresistance is enhanced. But the smaller f errimagnetic segregates become more sensitive to thermal agitation at high temp eratures. The weakness of the Al_doped SFMO lies in its stronger temperature dep endence of the saturated moments and the low_field magnetoresistance.
Study on the electromagnetic scattering and Doppler spectra from two-scale time-varying fractal rough sea surface
Authors: Guo Li-Xin  , Wang Yun-Hua  , Wu Zhen-Sen  ,   西安电子科技大学理学院，西安  710071
Published: December 2020

In this paper, the two-scale model method, which is much applicable to the comp utation of the electromagnetic scattering field from the rough sea surface, is used to calculate the backscattering cross-section of the one-dimensional time-varying fractal rough sea surface, the related results are also compared with those calculated by small perturbation method. The fractal characteristic of the Doppler spectra of the backscattering signal from the sea surface is studied, th e dependances of the the backscattering cross-section and the width of Doppler s pectra on the incident angle and fractal dimension are also analyed. Finally, th e relationship between the central frequency of the Doppler spectra and the Brag g resonant frequency is discussed in detail.
Optical constants of Ge nanolayers in oxidation of SiGe alloys determined by ellipsometry
Authors: Huang Wei-Qi  , Liu Shi-Rong  ,   (1)贵州大学物理系,光电子实验室，贵阳市  550026; (2)中国科学院地化所电镜室，贵阳市  550003
Published: December 2020

We investigate the oxidation behavior of Si1-xGex alloys ( x=0005，002，005，015 and 025). A new ellipsometric method is used f or the generating and measuring Ge nanostructures in oxidation of SiGe alloys. The fundamental optical constants of Ge nanolayers in the sample were determined by ellipsometry. The thickness and origin of the Ge bi_nanolayer were found. A new peak in photoluminescence PL spectra was discovered, which is related to the Ge bi_nanolayer (thickness: 08—14nm). Some suitable model and calculating formula can be provided with the UHFR method and quantum confinement analysis to interprete the PL spectrum and the nanostructure mechanism in the oxide.
Solitary wave solution of Zakharov equation with quantum effect
Authors: Wang Yue-Yue  , Yang Qin  , Dai Chao-Qing  , Zhang Jie-Fang  ,   浙江师范大学非线性物理研究所，金华  321004
Published: December 2020

With the help of Maple procedure, the Zakharov equation, which takes the quantum effect into account, is solved by means of extended tanh-function method and bifunction method. Several solitary wave solutions are obtained, including bright soliton, W-shaped soliton, M-shaped soliton and singular solutions.
Diffraction enhanced imaging computer tomography
Authors: Shu Hang  , Zhu Pei-Ping  , Wang Jun-Yue  , Gao Xin  , Yin Hong-Xia  , Liu Bo  , Yuan Qing-Xi  , Huang Wan-Xia  , Luo Shu-Qian  , Gao Xiu-Lai  , Wu Zi-Yu  , Fang Shou-Xian  ,   (1)首都医科大学，北京  100054; (2)中国科学院高能物理研究所,北京  100049; (3)中国科学院高能物理研究所,北京  100049;中国科学院研究生院,北京  100049
Published: December 2020

Diffraction enhanced imaging is a new X-ray radiographic imaging method using monochromatic X-rays from a synchrotron source which produces high contrast and spatial resolution images of thick absorbing objects. Use of this method in medicine, material science and industrial applications in non-destructive testing is highlighted at present. The purpose of this study is to discuss diffraction enhanced imaging computer tomography which combines computer tomography (CT) and diffraction enhanced imaging (DEI) method. Comparison between DEI-CT images with conventional X-ray CT images shows that the DEI-CT imaging technique gives not only surface information but also the internal structure of organs or soft tissues with high contrast. The obtained images show the micro-structures details of DEI-CT.
Resonant tunneling and photon emission of an ultracold two-level atom passing through multi single-mode cavity fields
Authors: Sun Yu-Hang  , Li Fu-Li  ,   (1)西安交通大学应用物理系，西安  710049; (2)西安交通大学应用物理系，西安  710049;西安邮电学院应用数理系，西安  710061
Published: December 2020

We consider that an ultracold two-level atom passes through multi spatially separated single-mode cavity fields and investigate the influence of the center-of-mass motion of the atom, the length of the cavity and the separation between two cavities on the transmission and photon emission probabilities of the atom. We find that both the transmission and photon emission probabilities as functions of the cavity length have multi-resonance peaks when the separation between two cavities is equal to an integer multiple of half the de Broglie wavelength of the atomic center-of-mass motion. The present work shows that the wave function of the atomic center-of-mass motion may be modulated in a macroscopic level by arranging the cavities.
Dependence of number of trapped atoms on the experimental parameters of Rb magneto-optical trap
Authors: Jiang Kai-Jun  , Li Ke  , Wang Jin  , Zhan Ming-Sheng  ,   (1)中国科学院武汉物理与数学研究所波谱与原子分子国家重点实验室,武汉  430071;中国科学院冷原子物理中心，武汉  430071; (2)中国科学院武汉物理与数学研究所波谱与原子分子国家重点实验室,武汉  430071;中国科学院研究生院,北京  100080;中国科学院冷原子物理中心，武汉  430071
Published: December 2020

Our study indicates that the number of trapped Rb atoms in a magneto-optical trap (MOT) strongly depends on the trapping laser intensity and detuning, the repumping laser intensity and the magnetic gradient. We estimate the trapped-atom numbers changing with the trapping laser intensity and detuning, using a two-level system model. The theoretical results are in qualitative agreement with the experimental results. The experimental results also show an obvious dependence of the trapped-atom numbers on repumping laser intensity and the magnetic gradient, which the simple theory cannot account for. These studies are helpful for selecting suitable experimental parameters to achieve larger numbers of cold atoms.
Study of 3D optical chain with highly focused vector beam
Authors: Zhang Yan-Li  , Zhao Yi-Qiong  , Zhan Qi-Wen  , Li Yong-Ping  ,   (1)美国戴顿大学电子光学系, 戴顿; (2)中国科学技术大学物理系,合肥  230026
Published: December 2020

We present a design of diffractive optical element to produce 3D optical chain along optical axis near the focus of a high numerical aperture (NA) lens by spatially modulating the phase of incoming vector beam. This optical chain can trap multiple individual particles in three dimensions at different planes near the focus. For flexibly controlling this special optical trapping system, we systematically analize the factors affecting the characteristics of the optical chain, such as different incoming vector polarization of light, the NA of the lens, and the structure of the DOE.
The sine-squared potential and properties of planar channelling radiation of positron
Authors: Luo Shi-Yu  , Shao Ming-Zhu  ,   东莞理工学院电子工程系，东莞  523106
Published: December 2020

The sine-squared potential is introduce to describe the interaction between particles and the crystal.The motion equation of the planar channelling particles is reduced to the pendulum equatione by this interaction potential.The solution of the equation and the period of the particle motion are expressed exactly by means of Jacobian elliptic function and elliptic integral.The radiation intensity and properties of the radiation spectrum are discussed.It is point out that it is possible to take channeling radiation as a new γ-Laser.
Photoionization studies of C2Cl4 using synchrotron radiation
Authors: Ma Jing  , Ding Lei  , Gu Xue-Jun  , Zheng Hai-Yang  , Fang Li  , Zhang Wei-Jun  , Huang Chao-Qun  , Wei Li-Xia  , Yang Bin  , Qi Fei  ,   (1)中国科学技术大学国家同步辐射实验室,合肥  230029; (2)中国科学院合肥物质科学研究院安徽光学精密机械研究所环境光谱学研究室,合肥  230031
Published: December 2020

The photoionization and photodissociation processes of C2Cl4 were investigated under the supersonic molecular beam conditions by using a reflectron-time-of-flight mass spectrometer (TOF-MS) and vacuum ultraviolet (VUV) photons from synchrotron radiation source. The photoionization mass spectrum and the photoionization efficiency (PIE) curves of the parent ion and some fragment ions were measured. The appearance potentials of these ions are obtained from their PIE curves. The formation enthalpies of some major ions and the dissociation energy of C2Cl4 have been evaluated from these data. According to the experimental results and the energy calculated by G1 theory, the main possible channels of dissociative photoionization of C2Cl4 have been discussed. In the future, we can detect C2Cl4 with single photon ionization(SPI)-TOFMS technique using 118.0nm laser radiation. This is based on the mass spectrum obtained at the wavelenth by using synchrotron radiation source.
Geometries and the electronic structures of t-HfO2 (001) surface
Authors: Lu Hong-Liang  , Xu Min  , Chen Wei  , Ren Jie  , Ding Shi-Jin  , Zhang Wei  ,   复旦大学微电子学系，ASIC与系统国家重点实验室，上海  200433
Published: December 2020

The geometries and the electronic structures of t-HfO2 and its (001) surface have been studied by first-principle calculations using the density func tional theory (DFT). The optimized results show that the t-HfO2 (001) surface has no surface reconstruction. Compared with the bulk electronic struct ure, the density of states (DOS) of t-HfO2 (001) surface is higher th an that of the bulk. In addition, the DOS of t-HfO2 (001) surface is closer to the Fermi level. The valence band has the tendency to move toward the lower energy, resulting in the formation of a new surface state. The band gap of t-HfO2 (001) surface is much smaller than that of bulk band gap. The existence of a new surface state and the reduction of band gap are due to the r eduction of the Hf and O surface coordination which are different from the bulk atoms.
Growth and properties of the c-axis oriented Bi3.15Nd0.75 Ti3O12 ferroelectric multi-layer thin films on silicon substrates
Authors: Li Shao-Zhen  , Li Mei-Ya  , Xu Wen-Guang  , Wei Jian-Hua  , Zhao Xing-Zhong  ,   (1)武汉大学物理科学与技术学院,武汉  430072; (2)武汉大学物理科学与技术学院,武汉  430072;武汉大学纳米科学与技术研究中心，武汉  430072
Published: December 2020

The c-axis oriented Bi3.15Nd0.75Ti3O12(BNT) ferroelectric thin films were grown on Si(100) substrates by pulsed lase r deposition with La0.5Sr0.5CoO3/CeO2/Y0.18Zr0.91O2.01 multi-heterostructure as buf fer layer. X-ray diffraction and scanning electron microscopy were used to deter mine the microstructure, orientation and morphology of the multi-layer films. Th e influence of deposition temperatures and the partial oxygen pressure on the mi crostructure, orientation and morphology of the BNT films were investigated and the optimal deposition parameters were determined. The BNT multi-layer thin film s deposited under optimal condition have good electric properties. The C-V patte rn of the BNT multilayer thin films deposited under optimal deposition condition s has the typical butterfly-like shape, suggesting that the films have good pola rization-reversion storage properties. The correlation between the ferroelectric properties and the orientations of the BNT films is discussed.
Numerical simulation of solute segregation patterns for a binary alloy using phase-field approach
Authors: Zhu Chang-Sheng  , Wang Zhi-Ping  , Jing Tao  , Xiao Rong-Zhen  ,   (1)兰州理工大学计算机与通信学院，兰州  730050; (2)清华大学机械工程系，北京  100084
Published: December 2020

The dependence of denderitic patterns and solute segregation on solid diffusivit y Ds is studied using a phase-field model which incorporates concentr ation field for Ni-Cu binary alloy dendritic growth. The computed results indica te that with the decrease of solid diffusivity Ds, the smaller become s the thickness of the solute diffusion layer ahead of the interface, which is a dvantageous to the growth of the sidebranching, and the more developed the side- branches. The smaller the solid diffusivity Ds, the more acutely the solute concentration in solid phase fluctuates. With the increment of solid diff usivity Ds, the fluctuations of solute concentration in solid phase a re reduced accordingly. An increased level of solid diffusivity Ds re duces the severity of microsegregation.
Time evolution of mesoscopic RLC circuit driven by an alternating current source
Authors: Liu Qing  , Zou Dan  , Ji Ying-Hua  ,   (1)江西师范大学物理与通信电子学院,南昌  330022; (2)江西师范大学物理与通信电子学院,南昌  330022;井冈山学院物理系,吉安  343009
Published: December 2020

According to the LR invariant theory, the mesoscopic RLC circuit driven by a alternating current source was discussed. The mutual coupling of electron wave functions between the two plates of capacitor and the resistance of the circuit were taken into account. In our conclusion, the quantum states which dominate the dynamic property of the system and the time evolution operator of the mesoscopic circuit were obtained. The wave function of the mesoscopic RLC system will evolve from an arbitrary initial state to a generalized squeezed state.
Theoretical study of cascade synchronization in chaotic lasers and chaotic repeater
Authors: Yan Sen-Lin  , Wang Sheng-Qian  ,   (1)江西科技师范学院通信与电子工程学院，南昌  330013; (2)江西科技师范学院通信与电子工程学院，南昌  330013;南京晓庄学院物理系，南京  210017
Published: December 2020

The chaotic repeater is proposed for long-haul chaotic communications. The physical model of all optical chaotic semiconductor laser repeater is presented. The synchronization of chaos repeater system is theoretically demonstrated. Chaos synchronization of a transmitter, a repeater and a recoverer is numerically achieved. Relationships of synchronization error and synchronization time with the system feedback coefficient are analyzed. Application of the repeater system is numerically simulated in chaotic laser communications. Chaotic communications and synchronization error analysis with a sinusoidal modulation signal of frequency 0.2GHz and a digital signal of 0.2Gb/s rate are given respectively to illustrate that chaotic repeater can improve the decoding quality in chaotic laser communications. The repeater bandwidth, chaotic communications with a high rate digital signal of 20Gb/s and synchronization error are analyzed respectively. Numerical results of a sinusoidal modulation signal of bandwidth from 0.1 to 20GHz, and a digital signal of modulation bandwidth from 0.1 to 20Gb/s are obtained, and numerical relationship of synchronization error to the modulation frequency is also shown. The system parameter mismatch is also numerically analyzed.
Padé-finite-difference time-domain analysis of electromagnetic scattering in magnetic anisotropic medium
Authors: Yang Li-Xia  , Ge De-Biao  ,   西安电子科技大学理学院，西安  710071
Published: December 2020

Based on the matrix Padé approximation theory, the complex relative permeability tensor of magnetized dispersive media is described by a matrix function expansion with respect to jω in frequency domain. By substituting the operator of /t into jω, the expansion is then transferred into the time-domain. In order to derive the formulation of the matrix expansion of complex relative permeability tensor in discretised time domain, a shifted operator in discretised time domain is introduced as a replacement of time differential operator /t. Therefore the dispersion relation between B and H in discretised time domain can be obtained, which is then implemented to the gyrotropic medium, yielding the time iterative formulation for finite-difference time-domain computation. To verify the feasibility of the presented scheme, we apply the above-mentioned method to the electromagnetic scattering by a magnetized ferrite sphere. The computed result is in good agreement with the one obtained by recursive convolution technique. The analysis and example show the feasibility of the proposed scheme.
Horn waveguide couplers for interfacing between two-dimensional photonic crystal and single mode planar dielectric waveguides
Authors: Zhang Bo  ,   北京交通大学电子信息工程学院，国家电工电子教学基地，北京  100044
Published: December 2020

We propose and optimize the horn waveguide couplers based on distributed Bragg reflector waveguide for coupling between two-dimensional dielectric cylinder photonic crystal waveguide and single mode planar dielectric waveguide and evaluate their transmission efficiency using the finite difference time domain method. The simulation results show that the power transmission efficiency is over 98% in a large part of the frequency range of the guided mode of photonic crystal waveguide. The highest transmission efficiency is 99.85%.
Effect of number of unit cells of fcc photonic crystal on property of band gaps
Authors: Li Rong  , Cheng Yang  , Cui Li-Bin  , Zhu Feng  , Zhou Jing  , Liu Da-He  , Liu Shou  , Zhang Xiang-Su  ,   (1)北京师范大学物理系，应用光学北京市重点实验室，北京  100875; (2)厦门大学物理系，厦门  361005
Published: December 2020

The effect of number of unit cells of the fcc photonic crystals on the property of the band gaps was investigated experimentally. Fcc photonic crystals with different numbers of cells were fabricated by using recording materials of different thickness in holography. Their transmitted spectra of the band gaps were measured. A guiding rule was given: a photonic crystal which can be practically used should have 50 unit cells at least.
Structure of radio-frequency flat plasma sheath in an oblique magnetic field
Authors: Zou Xiu  ,   大连交通大学数理系，大连  116028
Published: December 2020

A radio frequency flat plasma sheath model in an oblique magnetic field is built, which has one-dimensional coordinate space and three-dimensional speed space. The effect of magnetic field on the structure of radio frequency sheath and characteristic parameters are discussed. The numerical simulation results show that the effect of magnetic field on the sheath structure cannot be ignored. In particular, it brings about obvious changes in the ion density distribution and velocity distribution. Furthermore, the magnetic field cannot change the total energy density distribution of ions, but the Lorentz force does influence its movement state, and at the same time affects the ion energy distribution in every directions, as well as the incidence departure angle of ions.
The luminescence and defects of F, Y co-doped PbWO4 crystals
Authors: Ye Chong-Zhi  , Liao Jing-Ying  , Yang Pei-Zhi  , Xie Jian-Jun  , Luo Lan  , Cao Dun-Hua  ,   (1)同济大学波耳固体物理研究所，上海  200092; (2)中国科学院上海硅酸盐研究所，上海  200050
Published: December 2020

The influence of F,Y co-doping on the luminescence properties and defects of PbW O4 (PWO) have been investigated by correlated measurements of transmi ssion spectra, light yield, photoluminescence spectra, thermoluminescence and po sitron annihilation lifetime. F doping results in a new luminescence band peaked around 350nm, which gives a significant improvement in luminescence properties of PWO. Meanwhile, Y-dopant efficiently reduces trapping state and accelerates t he scintillation decay process. Compared with the undoped PWO samples, the light yield (100ns) of F,Y co-doped PWO　crystal was increased by a factor of 2.7. Th e main defects (WO3)- and (WO4)3- in PWO crystals for lack of oxygen during growth were investigated. Thermoluminesc ence results show that the defects in PWO crystals increase when annealed in vac uum and these defects can be also suppressed by annealing in air at 600℃.
PtN in zinc-blende structure: An unstable metallic transition-metal nitride compound
Authors: Wang Song-You  , Duan Guo-Yu  , Qiu Jian-Hong  , Jia Yu  , Chen Liang-Yao  ,   (1)复旦大学先进光子学材料与器件国家重点实验室,上海  200433; (2)鹤壁职业技术教育学院，鹤壁  458000; (3)郑州大学物理工程学院，郑州  450052
Published: December 2020

Using the first principle calculations based on density function theory with the generalized gradient approximation and local density approximation，we studied electronic structure and mechanical stability of the recently synthesized nitrid e compound PtN with cubic structure. The results show that the PtN with zinc-ble nde structure is unstable. We further find that the rock-salt structure has a b igger cohesive energy than the zinc-blende structure, it is possible that a pha se transition from zinc-blende to rock-salt occurs under certain pressure.
Influence of light exposure and applied bias on the conductivity of microcrystalline silicon films at room temperature
Authors: Yu Yun-Peng  , Lin Xuan-Ying  , Lin Shun-Hui  , Huang Rui  ,   汕头大学物理系，汕头  515063
Published: December 2020

Microcrystalline silicon films were deposited using the plasma enhanced chemical vapor phase deposition system and SiCl4/H2 gas source. We investigate the evolution of the dark conductivity of the fabricated films afte r a brief exposure to light or under DC bias. Raman spectra measurements indicat e that the volume fractions of crystalline phase for all samples are over 70%. T he measurement of dark resistance reveals the existence of weak persistent photo conductivity in our samples. Under DC electric field, it is found that the dark conductivity increases slowly with time and a restoration process occurs once th e field is reversed. This behavior depends on the DC bias level and the measurem ent temperature and can be explained by a heterojunction barrier model. It is su ggested that the spatial separation and redistribution of charge carriers under applied conditions and the potential barrier associated with inhomogeneity are r esponsible for the observed phenomena.
Microstructure and photoabsorption of Au/SiO2 nano-composite films
Authors: Zhang Yun  , Zhang Bo-Ping  , Jiao Li-Shi  , Li Xiang-Yang  ,   (1)北京科技大学材料科学与工程学院，北京  100083; (2)北京科技大学材料科学与工程学院，北京  100083;大连理工大学环境与生命学院，大连  116024; (3)钢铁研究总院功能材料研究所，北京  100081
Published: December 2020

Au/SiO2 nano-composite multilayer thin films were prepared by magnetr on plasma sputtering. The microstructure, morphology and optical properties were investigated using transmission electron microscopy and absorption spectra. The Au particles dispersed in the SiO2 matrix of one single Au layer gre w with increasing deposition time in the initial time interval of less than 10s. No obvious change in the size of Au particles was observed in the films deposit ed for more than 10s, however, the shape of Au particles changed. The optical ab sorption peaks due to the surface plasma resonance appeared at a wavelength of 5 40—560nm for ［Au(t1)SiO2(600)］×5 thin films . The intensity of the absorption peak increased with increasing deposition time . Influence of the Au particle shape on the position and intensity of plasma res onance absorption peak was also discussed. The optical absorption spectra of Au/ SiO2 thin films are well in agreement with the theoretical optical ab sorption spectra calculated from reformed Maxwell-Garnett effective medium theor y.
Numerical experiments on a harmonized multi-time difference scheme
Authors: Zhang Li-Xin  , Gao Xin-Quan  , Li Jian-Ping  ,   (1)中国科学院大气物理研究所大气科学和地球流体力学数值模拟国家重点实验室，北京   100029; (2)中国气象局气候研究开放实验室，国家气候中心，北京  100081
Published: December 2020

Numerical experiments are performed on the chaotic movement of a simplified cli mate model. Considering various factors related to the predictability, we numeri cally compare the harmonized multi-time difference scheme (HMTDS) with the varia tional assimilation. It is shown that the HMTDS corrects remarkably the model bi as, especially the differential equation bias, which is just the drawback of the variational assimilation.
Lutzky conserved quantities and velocity-dependent symmetries for systems with unilateral holonomic constraints
Authors: Zhang Yi  ,   苏州科技学院土木工程系，苏州  215011
Published: December 2020

This paper studies the symmetries and the conserved quantities for systems with unilateral holonomic constraints. The definitions of Lie symmetries for the systems are given, and the Lutzky conserved quantities are directly deduced from the general velocity-dependent Lie symmetries of the systems. The Lutzky conserved quantities of some special cases, for example, the holonomic systems with remainder coordinetes, the non-conservative mechanical systems, and the Lagrangian systems, are given. At the end of the paper, two examples are given to illustrate the application of the results.
The time-revolution of the quantum fluctuation and the nonclassical statistical behavior for the polariton system
Authors: Yu Xiao-Min  , Liang Guo-Dong  , Zhong Yan-Hua  ,   (1)暨南大学物理系，广州  510632; (2)江门职业技术学院计算机系，江门  529020
Published: December 2020

In this paper, we have considered the polariton system described by the model effective Hamiltonian involving a single-mode photon field interacting with a transverse optical phonon in a more realistic form. On this basis, the dynamical evolution of the polariton system, and the quantum fluctuation and the non-classical properties for this system have been investigated in an analytic form. By the nonlinear interactions of the system, when the radiation field was initially in the coherent state and the polarization wave field in the vacuum state, the radiation field and the phonon field can be developed to the squeezed state with time evolution and their second-order squeezing oscillates with time evolution in a complex periodical form. When k1=0 or k2=0, the squeezed effects do not occur. The non-classical properties are determined by the nonlinear coupling of the system and depend on the existence of the k1 and k2 terms simultaneously. At the same time, it is shown that the new results indicate that the statistical distribution of the photon and phonon can oscillate between super-Poisson and sub-Poisson distribution with time evolution, the nonlinear terms k1(a++) and k2(a+b++ab) have contributions to the non-classical statistical feature.
Preparation of diamond-film based radiation detector
Authors: Ouyang Xiao-Ping  , Wang Lan  , Fang Ru-Yu  , Zhang Zhong-Bing  , Wang Wei  , Lü Fan-Xiu  , Tang Wei-Zhong  , Cheng Guang-Chao  ,   (1)北京科技大学功能材料研究所  100092; (2)清华大学工程物理系,北京  100084; (3)西北核技术研究所,西安  710024
Published: December 2020

Detector grade diamond films have been prepared by DC Arc Plasma Jet chemical vapour deposition from CH4-H2 mixtures.Diamond detectors of pulsed radiation based on the films have been developed and preliminarily studied.The responses of the detector to 1.25MeV γ ray and pulsed ultraviolet laser with picosecond width show that this detector has a very fast time-response and about 70% charge collection efficiency.Its further applications will be found in sub-nanosecond pulse measurements.
Design and modeling for 1.7—2.7 GHz broad-band left-handed material with miniaturized unit cell and its characterization
Authors: Meng Fan-Yi  , Wu Qun  , Wu Jian  ,   (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
Published: December 2020

An 1.7—2.7 GHz broad-band left-handed (LH) metamaterial with miniaturized unit cell is designed. The relative bandwidth of designed metamaterial is up to 45.5%， the electrical length of its unit cell is less than 0.035，and the transmission loss per unit cell is less than 0.75 dB in the whole operational band of the LH metamaterial. In this paper, the reflection and transmission characteristics of a semi-infinite LH metamaterial plate consisting of LH metamaterial cells is simulated, and the wave number, phase velocity, refraction index, effective permittivity and effective permeability are calculated. The results show the real part of the wave number and the refraction index and the velocity are negative while the real part of the effective permittivity and effective permeability are both negative in the 1.7—2.7 GHz band range.
Design of C band planar LH metamaterial and verification of the BW property
Authors: Meng Fan-Yi  , Wu Qun  , Wu Jian  ,   (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
Published: December 2020

A planar miniaturized left-handed (LH) metamaterial in C band is designed with broad bandwidth and low loss while the size of the unit cell is small and the structure is simple. In addition, the center of the frequency band where the LH metamaterial is applicable is tunable within the range of 4 to 20 GHz. A semi-infinite slab made of the planar LH metamaterial is simulated and the phase velocity is respectively extracted from the transmission and reflection data at normal incidence and the phase of wave front, results show the LH metamaterials studied exhibit backward wave (BW) properties in the frequency range of interest.
X-ray emission produced by interaction of highly ionized Arq+ ions with metallic targets
Authors: Yang Zhi-Hu  , Song Zhang-Yong  , Chen Xi-Meng  , Zhang Xiao-An  , Zhang Yan-Ping  , Zhao Yong-Tao  , Cui Ying  , Zhang Hong-Qiang  , Xu Xu  , Shao Jian-Xiong  , Yu De-Yang  , Cai Xiao-Hong  ,   (1)兰州大学现代物理系，兰州 730000; (2)咸阳师范学院物理系，咸阳 712000; (3)中国科学院近代物理研究所, 兰州  730000; (4)中国科学院近代物理研究所，兰州 730000
Published: December 2020

This paper studies the X-ray spectra produced by the interaction of highly charged ions of Arq+(q=16,17,18) with metallic surface of Be, Al, Ni, Mo and Au respectively. The experimental results show that the Kα　X-ray emerges from under the surface of solid in the interaction of ions with targets. The multi-electron excitation occurred in the process neutralization of the Ar16+　in electronic configuration of 1s2 in metallic surfaces, which produces vacancy in the K shell. Electron from high n state transition to K vacancy gives off X-ray. We find that there is no obvious relation between the shape of X-ray spectra and the different targets. The X-ray yield of incident ions are associated with initial electronic configuration. The X-ray yield of target is related to the kinetic energy of the incidentions.
Study of structure and stability of GanN－m anions
Authors: Li En-Ling  , Wang Xue-Wen  , Chen Gui-Can  , Ma Hong  , Xue Ying  ,   (1)西安交通大学微电子研究所，西安  710049; (2)西安交通大学微电子研究所，西安  710049；西安理工大学理学院，西安  710048; (3)西安理工大学理学院，西安  710048; (4)西北大学信息科学与技术学院，西安  710068
Published: December 2020

Structures and stability of GanN-(n=2—8) and GanN-2 (n=1—7) anionic clusters have been studied using the density functional theory (DFT). Structural optimization and frequency analysis were carried out at the B3LYP/6-31G* level. All ground states of GanN-(n=2—8) and GanN-2 (n=1—7) clusters have been obtained. Our calculations reveal that there exists a transition from planar to spacial structures at the total number of the atoms being 5 with increasing cluster size. Among different GanN-(n=2—8) and GanN-2 (n=1—7) anionic clusters, Ga4N-， Ga6N-, Ga4N-2 and Ga5N-2 are more stable.
Photonionization and radiative recombination of Br——Comparison of rate coefficients deduced form the average atom and detailed configuration models
Authors: Liu Ling-Tao  , Wang Min-Sheng  , Han Xiao-Ying  , Li Jia-Ming  ,   (1)清华大学物理系原子分子纳米科学教育部重点实验室，北京  100084; (2)上海交通大学物理系，上海  200030；清华大学物理系原子分子纳米科学教育部重点实验室，北京  100084
Published: December 2020

For practical purposes, the ionic stage and populations of hot dense plasma are often described by the average atom(AA) model instead of the detailed average configuration accounting(DCA) model, which is more close to the reality. According the atomic self-consistent field theory, we calculate the DCA reduced photonionization cross-sections of every subshell of Br ions in different ionic stages. Comparing these DCA reduced cross-sections with the reduced photonionization cross-secion of the corresponding average electronic orbital in the AA model, we deduce the inherent rules between the reduced cross-sections. Based on the AA reduced photonionization cross-section, the DCA reduced photonionization cross-sections and detailed configuration rate coefficients of photonionizaiton and radiative recombination can be calculated. This work is a necessary preparation for accurate description of non-local thermal equilibrium(n-LTE) plasma.
Symplectic analysis and dual edge element for electromagnetic waveguide
Authors: Chen Jie-Fu  , Zheng Chang-Liang  , Zhong Wan-Xie  ,   (1)大连海事大学机电与材料工程学院，大连  116026; (2)工业装备结构分析国家重点实验室，大连理工大学，大连  116023
Published: December 2020

The governing equations for the electromagnetic waveguide are derived to Hamiltonian system formulation and symplectic geometric form, and transverse electric and magnetic components are treated as dual vectors to each other. By separation of variables, we arrived at a symplectic eigenvalue problem for Hamiltonian operator matrix, which can be solved by adjoint symplectic orthonormal relationship and the symplectic eigenfunction expansion method. A dual edge element is proposed for electromagnetic waveguide with irregular cross section and inhomogeneous loaded materials. Dual edge element can surmount those difficulties related to node-based finite elements in computational electromagnetics, and our numerical examples show that dual edge element has its own merits when compared with regular edge element.
Restoration of pinhole images using Lucy-Richardson algorithm
Authors: Kong Xiang-Long  , Li Yu-Tong  , Yuan Xiao-Hui  , Yu Quan-Zhi  , Zheng Zhi-Yuan  , Liang Wen-Xi  , Wang Zhao-Hua  , Wei Zhi-Yi  , Zhang Jie  ,   (1)中国科学院物理研究所光物理重点实验室，北京  100080; (2)中国科学院物理研究所光物理重点实验室，北京  100080；中国科学技术大学少年班系，合肥  230026; (3)中国科学院物理研究所光物理重点实验室，北京  100080；中国科学院西安光学机械研究所瞬态光学国家重点实验室，西安  710068
Published: December 2020

The matrix of the point spread function for an X-ray pinhole camera system has been calculated. The computer-simulated pinhole images and real pinhole images measured in laser-plasma experiments have been restored using Lucy-Richardson algorithm. The number of iterations the resolution of the restored imaging and the details of the restore method have been discussed. The reliability of the restoration algorithm is also verified by a simulated optical experiment.
Numerical simulation of acceleration of electrons and ions in the interaction of intense laser pulses with dense gaseous targets
Authors: Chen Min  , Sheng Zheng-Ming  , Zheng Jun  , Zhang Jie  ,   中国科学院物理研究所光物理重点实验室,北京  100080
Published: December 2020

Using a one-dimensional particle-in-cell code, which includes field ionization and electron collisional ionization, as well as elastic binary Coulomb collisions, we study the acceleration of electrons and ions by the interaction of an intense laser pulse (1017—1018W/cm2, 26.7fs) with a helium gas target (1021—1022/cm3, 0.8 μm thick). It is shown that field ionization appears quickly at the target front surface. Collisional ionization is found inside the target by energetic electrons, which are accelerated by the laser fields at the front surface and transported into the target. Part of these electrons transmits through the target rear surface and induces an electrostatic field there. This field further leads to field ionization at the rear surface. Meanwhile, it accelerates new-born ions produced there through the field ionization. Because of the electrostatic fields induced at the two target surfaces, some electrons oscillate between them, resulting in oscillating energy exchange between electrons, ions and the electrostatic fields. Particular attention is also paid to the origins of accelerated ions. Under certain conditions, ions accelerated inside the target are more energetic than those accelerated at the target surfaces.
Phase-field simulation of the influence of elastic field on microstructure evolution and equilibrium composition of precipitation
Authors: Zhang Yu-Xiang  , Wang Jin-Cheng  , Yang Gen-Cang  , Zhou Yao-He  ,   西北工业大学凝固技术国家重点实验室，西安  710072
Published: December 2020

We have simulated the microstructure evolutions of coherent single precipitate and multi-precipitates with inhomogeneous eigen elastic field and applied external strain using phase-field method. The influences of the inhomogeneous eigen elastic field and applied external strain on the morphology pattern of the coherent precipitate are discussed, and the effect of the elastic field on the equilibrium compositions of the precipitate and the matrix phase is also analyzed.
Charge storage characteristics in hybrid electret film consisting of porous PTFE and PP with negative corona charging
Authors: Chen Gang-Jin  , Xiao Hui-Ming  , Xia Zhong-Fu  ,   (1)同济大学波耳固体物理研究所，上海  200092; (2)浙江科技学院功能材料研究所,杭州  310012
Published: December 2020

The charge storage characteristics of hybrid electret film consisting of porous PTFE and PP, which come from Shanghai Dagong New Materials Co. Ltd., are investigated by means of corona charging, open-circuit thermally stimulating discharge (TSD ) analysis and isothermal surface-potential measurement. The results indicate that there are space charge and polar charge for the hybrid film charged by means of corona discharge method, and the interface between PP and PTFE layers are the main source of charge traps. When charging is carried out through different sides, the difference of TSD current spectra is very large. The electric field generated by space charge can cause polarization of polymer and give rise to polar charge, which exists as compensative charge of space charge, so that the surface potential measurement can't reveal the charge characteristics inside hybrid films.
A high sensitivity fiber-optic torsion sensor based on a novel ultra long-period fiber grating
Authors: Zhu Tao  , Rao Yun-Jiang  , Mo Qiu-Ju  ,   (1)成都电子科技大学通信与信息工程学院，成都  610054;重庆大学光电工程学院，重庆  400030; (2)重庆大学光电工程学院，重庆  400030; (3)重庆大学光电工程学院，重庆  400030;成都电子科技大学通信与信息工程学院，成都  610054
Published: December 2020

A high sensitivity fiber-optic torsion sensor is described,which measures twist rate and determines twist direction simultaneously by using a novel ultra long-period fiber grating (ULPFG) with periods of up to several millimeters fabricated by high frequency CO2 laser pulses. The torsion characteristics of a ULPFG are analyzed based on the coupling theory and birefringence phenomena. The experimental results show that a higher torsion sensitivity of 0.2244nm/(rad/m) for high order resonant modes was obtained, which is four times higher than that of the long-period fiber grating written by high frequency CO2 laser pulses. Finally, an intensity-type demodulation approach for the realization of real-time torsion measurement is proposed and demonstrated based on the edge filtering effect of the ULPFG.
Dielectric breakdown of BST thin films prepared by RF sputtering
Authors: Lu Xiao  , Wu Chuan-Gui  , Zhang Wan-Li  , Li Yan-Rong  ,   电子科技大学微电子与固体电子学院，成都  610054
Published: December 2020

Dielectric breakdown of BST thin films prepared by RF sputtering is studied in this paper. It is found that, the BST thin films will have already broken before the voltage reaches to conventional breakdown strength, which is normally tested by ramping the voltage and recording the voltage at which an abrupt rise in leakage current is observed. Accordingly, another state of BST thin films, i. e. the incipient breakdown, is found instead. The model which describes the films' configuration changes with the increase of voltage is established, and a new method to determine the practical breakdown strength is proposed.
Magnetoelectric effect in bilayers of (Ni0.8Zn0.2Fe2O4)epoxy-PZT
Authors: Zhang Ru  , Wang Miao  , Zhang Ning  , Srinivasan G.  ,   奥克兰大学物理系，罗切斯特 MI 48309,USA;南京师范大学磁电子学实验室，南京 210097
Published: December 2020

In this paper we discuss the magnetoelectric (ME) effect in bilayers of Nickle Zinc ferrite (NZFO) and lead zirocnate titanate (PZT). The powder of NZFO was prepared by sol-gel technique, then hot-pressed at 900℃, and sintered at high temperatures. In these bilayers we measured strong magnetoelectric interaction and observed that the transverse ME effect was higher than the longitudinal effect by one order of magnitude, and the ME effect tended to be stronger as the sintering temperature of NZFO increased. When the sintering temperature was increased from 950℃ to 1380℃, the maximum voltage coefficient of transverse ME effect could change in the range of 25.6 mV Am-2≤αE≤199.6mV Am-2. Theoretical analysis shows that the ME effect observed in these samples origins from a good magnetoelectric coupling between NZFO and PZT.
Magnetic and optical properties of Co doped ZnO powders synthesized by solid-state reaction
Authors: Liu Xue-Chao  , Shi Er-Wei  , Song Li-Xin  , Zhang Hua-Wei  , Chen Zhi-Zhan  ,   (1)中国科学院上海硅酸盐研究所，上海  200050; (2)中国科学院上海硅酸盐研究所，上海  200050；中国科学院研究生院，北京  100049
Published: December 2020

Co doped ZnO powders were synthesized by the solid-state reaction. The magnetic and optical properties of the powders were investigated. The experimental results indicate that Zn2+ ions were substituted by Co2+ ions randomly. Zn0.95Co0.05O powders prefer paramagnetic state to ferromagnetic state from 3 K to 300 K due to coupling exchange interactions between Co 3d spins, which makes the nearest Co2+ antiparallel.
Effects of annealing on electron-beam evaporated 193nm Al2O3/MgF2 HR mirrors
Authors: Shang Shu-Zhen  , Shao Jian-Da  , Shen Jian  , Yi Kui  , Fan Zheng-Xiu  ,   (1)中国科学院上海光学精密机械研究所光学薄膜技术与研究发展中心，上海  201800; (2)中国科学院上海光学精密机械研究所光学薄膜技术与研究发展中心，上海  201800;中国科学院研究生院，北京  100049
Published: December 2020

193nm Al2O3/MgF2 HR mirrors were designed and deposited by electron-beam evaporation, and then annealed in air at different temperatures from 250℃ to 400℃. The center wavelength shifted to shorter wavelength after annealing. And the reflectance of HR region increased but the transmittance changed negligibly little with the increasing of the annealing temperature. The total integrated scattering was measured to distinguish the scattering loss and the absorption loss. The results indicated that the total optical loss in the HR region was absorption dominant rather than scattering dominant. To know clearly the loss-reduction mechanism of annealing, the corresponding single-layers of Al2O3 were deposited and annealed in the same way. The change of optical constants was analyzed to explain the reduction of the total optical loss. And the reflectance of the HR mirrors reached was higher than 98%.
Hydrogen storage properties of CNTs treated at different temperature in vacuum
Authors: Yi Shuang-Ping  , Zhang Hai-Yan  , Ouyang Yu  , Wang Yin-Hai  , Pang Jin-Shan  ,   (1)广东工业大学材料与能源学院，广州  510009; (2)广东工业大学物理与光电工程学院，广州  510009; (3)广东工业大学物理与光电工程学院，广州  510009;广东工业大学材料与能源学院，广州  510009; (4)湖南大学政策研究办，长沙  410082
Published: December 2020

The effect of multi-wall nanotubes (MWNTs) treated at different temperature in vacuum on the electrochemical hydrogen storage properties were investigated. The MWNTs were synthesized by chemical vapor deposition. The CNTs(carbon nanotubes)-LaNi5 electrodes were prepared by mixing MWNTs and LaNi5 alloy in a weight ratio of 1∶10. Three-electrode system was introduced. The CNTs-LaNi5 electrodes were used as the working electrode. Ni(OH)2/NiOOH worked as the counter electrode and Hg/HgO as the reference electrode. 6mol/L KOH solution acted as the electrolyte. Results showed that the CNTs-LaNi5 electrodes with CNTs treated at 850℃ in vacuum has the best electrochemical hydrogen storage capacity with a maximum discharging capacity of 503.6mAh/g and a corresponding discharging plateau voltage of 1.18V under the same testing condition. From 500℃ to 850℃, the higher the temperature of heating, the better the electrochemical hydrogen storage property of WMNTs. However, CNTs-LaNi5 electrodes with CNTs treated at 950℃ in vacuum has lower discharging capacity under the same testing condition. This shows that the temperature of CNTs treatment in vacuum is an important factor that influences its electrochemical hydrogen storage performance.
Z-scan experiment on soluble carbon nanotubes
Authors: Zhang Peng  , Niu Yan-Xiong  , He Chen-Juan  , Yu Ye  ,   (1)军械工程学院光学与电子工程系,石家庄  050003; (2)军械工程学院光学与电子工程系,石家庄  050003;天津大学精密仪器与光电子工程学院,光电信息技术科学教育部重点实验室,天津  300072; (3)中国科学院物理研究所光物理实验室,北京  100080
Published: December 2020

The Z-scan experiments were carried out to investigate the soluble carbon nanotubes. The thickness of sample is changed in order to study “thin” and “thick” sample respectively. The experiments are carried out using 8ns, 10Hz repetition rate laser pulses at 1064nm and 532nm. The transmittance curves of closed-aperture Z-scan show that nonlinear refraction is not the optical limiting mechanism of solubilized carbon nanotubes. The curves of opened-aperture Z-scan indicate that nonlinear absorption exists in this solution obviously, which may be the primary optical limiting mechanism of this material.
Wavelength converter based on cross-gain modulation in multi-electrode single-port-coupled semiconductor optical amplifier
Authors: Li Pei-Li  , Huang De-Xiu  , Zhang Xin-Liang  , Zhu Guang-Xi  ,   (1)华中科技大学电子信息与工程系，武汉  430074; (2)华中科技大学武汉光电国家实验室，武汉  430074; (3)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 cross-gain modulation (XGM) wavelength converter based on multi-electrode single-port-coupled semiconductor optical amplifier (SOA) is proposed, and a comprehensive broad-band dynamic model of this kind of wavelength converter is presented. By numerical simulation, the output performances of two kinds of XGM wavelength converter based on multi-electrode single-port-coupled SOA and based on single-port-coupled SOA are investigated. The result shows that the extinction ratio of XGM wavelength converter based on multi-electrode single-port-coupled SOA is greater than that of the later.
Specltal properties of Er3+ doped high silica glass
Authors: Da Ning  , Yang Lü-Yun  , Peng Ming-Ying  , Meng Xian-Geng  , Zhou Qin-Ling  , Chen Dan-Ping  , Tomoko Akai  , Kohei Kadono  ,   (1)日本产业技术综合研究所，大阪 563-8577 日本; (2)中国科学院上海光学精密机械研究所，上海  201800; (3)中国科学院上海光学精密机械研究所，上海  201800；中国科学院研究生院，北京  100080
Published: December 2020

The Judd-Ofelt intensity parameter Ωt of a novel Er3+ doped high silica glass was calculated. The large values of Ω2,6 (Ω2=8.15×10-20,Ω6=1.22×10-20) indicate that the local structure of Er3+ has higher asymmetry and lower covalency than other oxide glasses. McCumber theory was used to calculate the stimulated emission cross section of 4I13/2→4I15/2 transition, the result was 0.51pm2. Despite the Er3+-doped concentration in high silica glass being about ten times greater than that in silica fiber, its fluorescence lifetime and quantum efficiency were 6.0ms and 66.0%， respectively. This novel Er3+-doped glass can be used in optical amplification and microchip laser.
Numerical simulation of the influence of substitutional impurity on the interaction between low-energy Pt atoms and Pt(111) surface
Authors: Zhang Chao  , Wang Yong-Liang  , Yan Chao  , Zhang Qing-Yu  ,   大连理工大学三束材料改性国家重点实验室，大连  116024
Published: December 2020

The deposition process of low-energy Pt atoms on Pt (111) surface doped with substitutional impurity Cu, Ag, Au, Ni, or Pd was studied by using molecular dynamics simulation. The atomic interaction potentials with the embedded atom method (EAM) were applied in the simulation. The effects of substitutional impurity on the adatom yield, sputtering yield, and vacancy yield have been observed and summarized. We found that substitutional impurity considerably affects the adatom yield, sputtering yield, and vacancy yield. The main reasons influencing the interaction between low-energy atoms and Pt (111) surfaces are the kinetic energy of incident atoms and the mass of substitutional impurity. The light substitutional atoms induced the preferred sputtering of substitutional impurity. A model based the binary collision theory and the atomic reflection mechanism by the substrate is suggested to describe the low-energy deposition process.