bluuebunny/crossref_metadata_2025 huggingface dataset:
Characteristics of high- and low-dose-rate damage for domestic npn transistors of various emitter areas
Authors: Zheng Yu-Zhan  , Lu Wu  , Ren Di-Yuan  , Wang Yi-Yuan  , Guo Qi  , Yu Xue-Feng  , He Cheng-Fa  ,   (1)中国科学院新疆理化技术研究所,乌鲁木齐  830011; (2)中国科学院新疆理化技术研究所,乌鲁木齐  830011；中国科学院研究生院,北京  100049
Published: December 2020

There are many factors such as process technologies, dose rates and biased conditions which can affect radiation damage in npn transistors. High- and low-dose-rate radiation response of domestic npn transistors with three kinds of emitter areas were investigated in this article. The influence of emitter area on radiation damage was analyzed. The results show that the degradation of current gain was more severe at low dose rate, i.e. enhanced low-dose-rate sensitivity. Furthermore, radiation damage was more apparent at low current injection. Through the comparison of radiation damage for different emitter areas, it was found that greater perimeter-to-area ratio （P/A） would cause greater normalized excess base current （IB/IB0）. The damage mechanism for npn transistors is explained in detail, and the radiation hardness assurance is explored with respect to the emitter area and operating voltage of npn transistors.
First-principles study of the optical properties of ZnO doped with Al, Ni
Authors: Guan Li  , Li Qiang  , Zhao Qing-Xun  , Guo Jian-Xin  , Zhou Yang  , Jin Li-Tao  , Geng Bo  , Liu Bao-Ting  ,   河北大学物理科学与技术学院，保定  071002
Published: December 2020

The lattice structure, band structure, density of state and optical properties of pure ZnO, Al, Ni doped ZnO and Al-Ni codoped ZnO were calculated by first-principles method respectively. The results reveal that the imaginary part of the dielectric function of pure ZnO and Al-ZnO, Ni-ZnO, （Al,Ni）-ZnO have an obvious difference in the low energy range, but are similar in the high energy range. As to the optical properties, the absorption coefficient and reflectivity of Al-ZnO are much smaller than Ni-ZnO, which means a higher transmissivity in the visible light range. Especially, compared with Al, Ni doped ZnO, （Al,Ni）-ZnO has a significant change in the optical properties.
Gap states and microstructure of microcrystalline silicon thin films
Authors: Peng Wen-Bo  , Liu Shi-Yong  , Xiao Hai-Bo  , Zhang Chang-Sha  , Shi Ming-Ji  , Zeng Xiang-Bo  , Xu Yan-Yue  , Kong Guang-Lin  , Yu Yu-De  ,   (1)中国科学院半导体研究所材料科学重点实验室，北京  100083; (2)中国农业大学应用物理系，北京  100083
Published: December 2020

The density of states （DOS） above Fermi level of hydrogenated microcrystalline silicon （μc-Si:H） films is correlated to the material microstructure. We use Raman scattering and infrared absorption spectra to characterize the structure of the films made with different hydrogen dilution ratios. The DOS of the films is examined by modulated photocurrent measurement. The results have been accounted for in the framework of a three-phase model comprised of amorphous and crystalline components， with the grain boundary as the third phase. We observed that the DOS increases monotonically as the grain boundary volume fractions fgb is increased， which indicates a positive correlation between the DOS and the grain boundary volume fraction.
The effect of aging treatment on the magnetic properties of PtCo alloys
Authors: Liu Tao  , Li Wei  ,   钢铁研究总院功能材料研究所，北京  100081
Published: December 2020

The effect of aging temperature on the magnetic properties has been studied. The magnetic measurement results indicate that the remanence decreases with increasing aging temperature Ta，and the coercivity has a maximum value at Ta=690℃. After the first aging， the degree of ordering increases with Ta， which shows that the grain size of ordered phase also increases. This is the reason for the change of the coercivity. After the second aging， the microstructure does not change and the anisotropy field of ordered phase increases， which leads to an increase in the coercivity.
Synthesis，structures and luminescence properties of SnO2 nanoparticles
Authors: Lin Tao  , Wan Neng  , Han Min  , Xu Jun  , Chen Kun-Ji  ,   (1)南京大学化学系，南京  210093; (2)南京大学物理系，固体微结构国家重点实验室，南京  210093; (3)南京大学物理系，固体微结构国家重点实验室，南京  210093；中国科学院上海技术物理研究所红外物理国家实验室，上海  200083
Published: December 2020

As a wide band-gap semiconductor，SnO2 films have attracted much attention due to their novel optical and electronic properties. It has been reported that the physical properties can be quite different when the size of SnO2 is reduced to nanometer scale due to the large surface-to-volume ratio and the quantum size effects，which may be applied in many kinds of devices, such as solar cells sensors. etc. It is interesting to study the synthesis of SnO2 nanoparticles and their physics properties. In the present work，a soft chemical technique was used to prepare SnO2 nanoparticles with uniform size and good crystallization in alkalescent solution. The surfactant was added during the preparation process to control the growth and agglomeration of crystal precipitates in the solution. X-ray diffraction spectra and transmission electron microscopy were used to characterize the structures of SnO2 nanoparticles before and after thermal annealing. It was found that the nanocrystalline SnO2 particles can be formed by the present technique and the size is about 4 nm with good crystallinity. With changing the preparation parameters，the size of nanocrystalline SnO2 particles is changed. Post thermal annealing at various temperatures （400—1000 ℃） can promote the crystallization and the size of formed particles was increased with increasing annealing temperature. Optical absorption spectra were used to see the change of the optical properties for samples prepared under different conditions. It was found that the optical band gap is enlarged in nanocrystalline SnO2 particles compared with its bulk counterpart, which can be attributed to the quantum confinement effect. The red-shift of the optical band gap with the particle size supported the quantum size effect. A broad photoluminescence band in the range of 350—750 nm can be detected in the annealed samples and the intensity was significantly enhanced after the thermal annealing. The luminescence peak energy was kept at 390 nm which was independent of the particle size. This luminescence band can be ascribed to the luminescence center associated with the oxygen vacancies on the SnO2 particle surface.
Lagrange symmetry for a dynamical system of relative motion
Authors: Mei Feng-Xiang  , Wu Hui-Bin  ,   北京理工大学理学院,北京  100081
Published: December 2020

This paper studies the Lagrange symmetry of a dynamical system of relative motion. The definition and the criterion of the symmetry of the system are established. The condition under which there exists a conserved quantity and the form of the conserved quantity are obtained.
Diffractive effect of quantum spectra in the annular billiard
Authors: Zhang Ji-Quan  , Zhang Yan-Hui  , Zhou Hui  , Jia Zheng-Mao  , Lin Sheng-Lu  ,   山东师范大学物理与电子科学学院,济南  250014
Published: December 2020

We analyze the quantum spectra of the two-dimensional annular billiard system based on the open-orbit quantum spectrum function, and respectively calculate the Fourier-transformed quantum spectra for various values of a parameter （in the case f=Rin/Rout）. The results show that the peak positions of quantum spectrum match with the lengths of classical orbits of particle motion very well ，and the semiclassical closed-orbit theory affords a good explanation. While the inner circle radius becomes comparaber with the de Brogile wavelength of the particle, the character of quantum spectrum changes essentially, turning out to be similar with the pattern of optical diffraction, which is a purely wavelike phenomenon and accords with Fresnel-Kirchhoff diffraction theorem. Our treatment provides a basis theory for researching the property of billiard system and microjunction transport, and opens a new way to investigate the diffraction of crystal and spectral analysis.
Realization of quantum fredkin gate in optics
Authors: Lin Qing  ,   福建省华侨大学厦门校区信息科学与工程学院,厦门  361021
Published: December 2020

In this article, an experimental scheme of quantum Fredkin gate is proposed. This scheme is based on the cross-Kerr effect between the photons and the ancillary coherent state. Only one coherent state is required, while the single photon detector and the coincidence measurement are not required, so this Fredkin gate is scalable. In addition, this is a nearly deterministic gate with the success probability 1/133, and it is feasible with the current experimental technology in optics.
The orbital effect of photon in the general stationary spacetime
Authors: Gong Tian-Xi  , Wang Yong-Jiu  ,   (1)湖南师范大学理论物理所,长沙  410081; (2)湖南师范大学理论物理所,长沙  410081；湖南科技大学物理学院,湘潭  411201
Published: December 2020

We calculate the orbital effect of photon in the axisymmetric field created by the spinning mass with electric charge and a large number of magnetic monopoles. By analyzing the result we found that the deflection effect caused by the electric charge and magnetic charge decreases the deflection effect caused by the mass of the field source, but the deflection effect caused by the spinning of the field source depends on the angle between the spinning direction of the field source mass and the direction of photon motion. We obtained interesting results in discussing the parameters of the celestial body.
Analysis of the fast-slow hyperchaotic Lorenz system
Authors: Han Xiu-Jing  , Jiang Bo  , Bi Qin-Sheng  ,   江苏大学理学院,镇江  212013
Published: December 2020

The stability of the origin of the hyperchaotic Lorenz system with two time scales is investigated. The characteristics of Hopf bifurcation from the origin, including the existence condition, the direction as well as the stability of bifurcating periodic solutions are discussed in detail, which can be demonstrated by the numerical simulations. With certain parameter, the fast-slow system can exhibit symmetric bursting and further lead to hyperchaotic movement. Based on the method of slow-fast analysis, different bifurcation forms between quiescent state and spiking has been revealed and the influence of coupling strength on slow passage effect is disscussed.
The existence of three types of generalized synchronization of non-autonomous systems
Authors: Hu Ai-Hua  , Xu Zhen-Yuan  , Guo Liu-Xiao  ,   (1)江南大学理学院,无锡  214122; (2)江南大学理学院,无锡  214122；江南大学信息工程学院,无锡  214122
Published: December 2020

The existence of three types of generalized synchronization of unidirectionally coupled non-autonomous systems is studied. When the modified response system collapses to an asymptotically stable equilibrium, asymptotically stable periodic or quasi-periodic orbits, under certain conditions, the existence of generalized synchronization can be turned to the problem of compression fixed point in the family of Lipschitz functions. Theoretical proofs are proposed to the exponential attractive property of generalized synchronization manifold. In addition, the Duffing system was taken for illustration and verification.
Adaptive synchronization of the fractional-order unified chaotic system
Authors: Zhang Ruo-Xun  , Yang Yang  , Yang Shi-Ping  ,   (1)河北北方学院理学院，张家口  075000; (2)河北师范大学物理科学与信息工程学院，石家庄  050016; (3)邢台学院初等教育学院，邢台  054001
Published: December 2020

This article proposes an adaptive synchronization method with only one controller for the fractional-order unified chaotic system, and adaptive controller and updating law of parameter are obtained. The controller employs a single variable, and the presented control scheme is suitable for a class of fractional-order chaotic systems. In addition, the synchronization is effective in the presence of noise. Numerical simulations are used to validate and demonstrate the effectiveness of the proposed method.
Estimating parameters of air-sea oscillator with MCMC method
Authors: Cao Xiao-Qun  , Zhang Wei-Min  , Song Jun-Qiang  , Zhu Xiao-Qian  , Wang Shu-Chang  ,   国防科学技术大学计算机学院，长沙  410073
Published: December 2020

The Markov chain Monte Carlo （MCMC） method is used to estimate the unknown parameters of air-sea oscillator system, which is a model of Eastern Pacific sea surface temperature （SST）. Firstly，the posterior probability density function for unknown parameters of air-sea oscillator system is deduced with the Bayesian formula. Secondly， the Adaptive Metropolis algorithm is used to construct the Markov Chains of unknown parameters. And the converged samples are used to calculate the mathematic expectation. The results of numerical experiments show that parameters estimated by the new method have high precision and the noise is filtered effectively from the observations.
Design and application of a device based on electromagnetic induction principle for electrical resistivity qualitative measurement of liquid and solid metals
Authors: Zhang Ming-Xiao  , Tian Xue-Lei  , Guo Feng-Xiang  ,   山东大学材料液态结构及其遗传性教育部重点实验室，济南  250061
Published: December 2020

A non-contact measuring device for electrical resistivity has been designed, which is based on electromagnetic induction principle. Using the device, the electrical resistivity of metals can be monitored during transition from liquid to solid state, which shows that the device is suitable for analysing the structure transition of metals and alloys during the cooling process.The design principle and construction of the device are detailedly described in this paper. The change of electrical resistivity of pure Zn and pure Sb, and hypereutectic Zn-70wt.%Sb alloy during cooling was measured by the device. The experiment results show that the device preforms well.
Temperature-dependent terahertz spectroscopy of D-, L- and DL-ornidazole
Authors: Ma Jin-Long  , Xu Kai-Jun  , Li Zhe  , Jin Biao-Bing  , Fu Rong  , Zhang Cai-Hong  , Ji Zheng-Ming  , Zhang Cang  , Chen Zhao-Xu  , Chen Jian  , Wu Pei-Heng  ,   (1)南京大学超导电子学研究所,南京  210093; (2)南京大学化学化工学院,南京  210093；中国药科大学物理化学研究室，南京  210009; (3)南京大学理论与计算化学研究所,南京  210093; (4)南京圣和药业有限公司，南京  210038
Published: December 2020

Terahertz time-domain spectroscopy （THz-TDS） has been used to measure the vibrational spectra of polycrystalline D-, L- and DL-ornidazole over the temperature range 6—298 K. The large differences of the spectra are observed in the frequency range 0.3 THz—2.5 THz, which indicates that THz-TDS is an effective tool to distinguish between enantiomers （D-, L-ornidazole） and its racemic compound （DL-ornidazole）. A number of absorption peaks which could not be observed at room temperature are well resolved in the low temperature range. This provides more experimental details for mode assignment. The evolution of these absorption features between 6 K and 298 K was continuously mapped. The absorption frequencies shift to lower values as temperature increases. The measured temperature dependence can be well fitted if we consider the phonon modes follow a Bose-Einstein distribution. Finally, the quantum chemical calculations were carried out to simulate the experimental THz spectra of the three samples in the range of 0.2—2.5 THz. Compared with the calculated results, the observed characteristic absorptions are explained at molecular level.
Detection of the self-assembly of poly-（N-isopropylacrylamide） on gold based on microcantilever sensor
Authors: Huang Yuan  , Liu Hong  , Zhang Qing-Chuan  ,   (1)中国科学技术大学，中国科学院材料力学行为和设计重点实验室，合肥  230027; (2)中国科学技术大学化学物理系，合肥  230026
Published: December 2020

A microcantilever sensor platform is used for detecting the self-assembly of poly-（N-isopropylacrylamide） （HS-PNIPAM） on gold surface. The change of the interaction between molecules caused by conformation transition will change the surface stress of the microcantilever which causes its bending. The kinetic curves of self-assembly can be obtained by real-time monitoring the deflection of the microcantilever using the optical lever read-out technique. HS-PNIPAMs of different molecular weight were used to study the self-assembly process, and the results showed that the kinetic curves can be divided into three stages corresponding to different conformations, respectively. The first stage cor responds to physical adsorption of HS-PNIPAM on gold-coated side. The second and third stages correspond to chemical adsorption on gold-coated side with conformation transition. The kinetic curves fit Langmuir adsorption isotherm well. The results also show that the reaction rate κ of HS-PNIPAM is far less than that of small molecules and decreases exponentially with the molecular weight; while the time of HS-PNIPAM’s self-assembly is far greater than that of small molecules and proportional to the molecular weight. The change of the surface stress is linear to the molecular weight of HS-PNIPAM.
Investigation of RF phase jitter in relativistic klystron amplifier
Authors: Yang Zhen-Ping  , Bian Qing-Quan  ,   (1)绵阳师范学院，绵阳  621000; (2)西南科技大学理学院,绵阳  621010
Published: December 2020

RF phase Jitter is a very important parameter for a relativistic klystron amplifier, and it is closely related with the physical processes in the klystron. In view of the physical process in the klystron, the RF phase jitter is theoretically studied together with particle in cell （PIC） simulation. The main factor which affects the RF phase jitter is deduced and verified in the PIC simulation. The RF phase jitter is significantly affected by the fluctuation of the beam voltage at the steady state when the cavity is in resonanec. The relation is linear in a certain range.
Study of the electromagnetic scattering from the rough sea surface with bubbles/foams by the modified two-scale method
Authors: Liang Yu  , Guo Li-Xin  ,   西安电子科技大学理学院,西安  710071
Published: December 2020

A volume-surface composite model of rough sea surfaces with water bubble layer driven by wind is presented in this paper. Based on the modified two-scale rough surface scattering theory, MIE theory and VRT （vector radiative transfer） theory, the difference of electromagnetic scattering properties of the water bubbles compared with those of water particles is investigated. The relations between the foam coverage of the sea surface and wind speed and air-sea temperature difference are analyzed. The dependence of back- and bistatic-scattering coefficient of Gaussian rough surface and empirical sea surface with/without foam layer on the incident and azimuthal angle, the wind speed, the wind direction, as well as the polarization are discussed in detail. The results of numerical simulations are analyzed and compared with the measured data from the relevant references.
Study on new period structures of left-handed material based on rectangular resonators and metal wires
Authors: Sun Ming-Zhao  , Zhang Chun-Min  , Song Xiao-Ping  , Liang Gong-Ying  , Sun Zhan-Bo  ,   西安交通大学理学院，非平衡物质结构与量子调控教育部重点实验室，西安  710049
Published: December 2020

We studied the new left-handed material cousisting of triangular and three rectangular split resonant rings （SRRs） based on rectangular resonators and metal wires through simulation and experiment. Simulated negative permeability material based on periodic structures of triangular and three rectangular SRRs, we found that two kinds of SRRs can generate negative permeability. We designed new kinds of left-handed materials consisting of two kinds of resonators based on rectangular resonators and copper wires, simulation shows the structures have good left-handed property in some frequency bands. We also fabricated experimental samples in which waves under go negative refraction when the frequency bands are 9.5—13.3GHz and 9.8—12.5GHz respectively. This has important significance on design and study of new periodic structures of left-handed materials.
Photonic band gaps of two-dimensional phononic crystals tuned and optimized by modifying the configuration
Authors: Xu Zhen-Long  , Wu Fu-Gen  ,   (1)广东工业大学实验教学部,广州  510090; (2)湄洲湾职业技术学院,莆田  351254；广东工业大学实验教学部,广州  510090
Published: December 2020

A method is introduced to tune and optimize the photonic band gaps （PBGs） of two-dimensional photonic crystals （PCs）. PBGs between the bands at low frequency can be tuned by an additional atom rod at arbitrary positions. Moreover, fixing up the two atom rods at optimal positions and tuning the lengths of the two cylinders, the normalized gap widths of PBGs could be enlarged with a suitable configuration. The results also show that the setting up of large PBGs depends on different degrees of symmetry of the system in the case of two atom rods in a unit cell, the larger PBGs at higher frequency require lower symmetry.
Direct simulation of the influence on the motion of particles in a Newtonian fluid by melting and convection
Authors: Liu Han-Tao  , Tong Zhi-Hui  , An Kang  , Ma Li-Qiang  ,   中北大学机电工程学院，太原  030051
Published: December 2020

The influence on the motion of single solid particles in a Newtonian fluid by melting and convection was directly simulated. The fluid motion was computed from the conservation laws. Density and viscosity change with the fluid temperature, the particles move according to the equations of motion of a rigid body under the action of gravity and hydrodynamic forces arising from the motion of the fluid. In the process of melting, a distinctive morphology develops due to the different heat flux around the particles surface, and the thermal gradient determines the melting rate. The phases were coupled by the fluid-particle mutual force, force moment and the boundary conditions. In our study four different situations were considered, namely the sedimentation in isothermal fluid without thermal convection and melting, sedimentation in cool fluid and hot fluid without melting, and sedimentation with thermal convection and melting. The results showed that the vortex shedding arising from the natural convection changes the sedimentation velocity and induces horizontal oscillating.
Kelvin-Helmholtz instability in compressible fluids
Authors: Wang Li-Feng  , Ye Wen-Hua  , Fan Zheng-Feng  , Sun Yan-Qian  , Zheng Bing-Song  , Li Ying-Jun  ,   (1)北京应用物理与计算数学研究所计算物理实验室,北京  100088; (2)北京应用物理与计算数学研究所计算物理实验室,北京  100088；浙江大学物理系，杭州  310028；北京大学应用物理与技术研究中心，北京  100871; (3)中国矿业大学（北京）,北京  100083; (4)中国矿业大学（北京）,北京  100083；北京应用物理与计算数学研究所计算物理实验室,北京  100088
Published: December 2020

Kelvin-Helmholtz instability in two-dimensional compressible fluid is analyzed by the high precision numerical scheme. The linear growth rate of the Kelvin-Helmholtz instability is especially explored. The relations among the initial static pressure, conductive Mach number and linear growth rate of the Kelvin-Helmholtz instability are quantitatively achieved at the case of the low and high Mach numbers. The simulation results agree with the experiment results in free shear layers and mixing layers. Simulation results show that the conductive Mach number is the proper parameter in definition the compression effect. The smaller the conductive Mach number is, the less compressible the fluid is. The linear growth rate of the Kelvin-Helmholtz instability decreases with the increasing conductive Mach number.
Low-frequency internal friction study of La1-xSrxFeO3-δ（0≤x≤2/3）system
Authors: Wu Xiu-Sheng  , Yang Chun-Li  , Chen Zhi-Jun  , Chen Chu-Sheng  , Liu Wei  ,   (1)安徽建筑工业学院先进建筑材料安徽省重点实验室，合肥  230022; (2)中国科学技术大学先进功能材料与器件实验室，合肥  230026
Published: December 2020

La1-xSrx FeO3-δ systems were investigated by low-frequency internal friction method. The results show that the curves of the internal friction and modulus versus temperature vary with the Sr-dopant content （x）. For the undoped sample，no obvious change on the internal friction and modulus curves was observed between -150—380℃，but the samples with x=0.25，1/3，0.5 and 0.6 show an intenal friction peak P1 with the feature of phase transitions，and the peak temperature moves toward lower temperature with incresing Sr content. This peak was suggested to be associated with a phase transition from rhombohedral to orthorhombic. The samples with x=0.25，1/3，0.5，0.6 and 2/3 show a relaxation type peak P2 accompanied by a decrease in modulus，which can be attributed to the motion of domain walls whose mobility was contolled by the diffusion of oxygen vacancies. The samples with x=0.5，0.6 and 2/3 show a rapid change in the curves of modulus versus temperature，which is related to a ferroelastic phase transition from rhombohedral to cubic.
Hydrophobic nature of fluorinated diamond-like carbon films prepared under different radio-frequency power
Authors: Zhu Li  , Jiang Mei-Fu  , Ning Zhao-Yuan  , Du Ji-Long  , Wang Pei-Jun  ,   苏州大学物理科学与技术学院，苏州  215006
Published: December 2020

The fluorinated diamond-like carbon （F-DLC） films were prepared by reactive magnetron sputtering under different radio-frequency power with trifluoromethane （CHF3） and argon （Ar） as source gases and pure graphite as a target. The hydrophobic nature of F-DLC films was studied. The result of measuring contact angle between double-stilled water and film surface shows that the maximal contact angle of film surface is approximately 115°. Factors influencing the hydrophobic nature of films were discussed by film surface morphology measured by atomic force microscopy （AFM）, Raman spectra as well as FTIR spectra. The result demonstrates that the hydrophobic nature of films lies on roughness and bonding configuration of film surfaces. The more the roughness，the stroncer the hydrophobic nature is，but it doesnt show a simple decrease or increase with the content of F in films and the ratio of sp3/sp2. Radio-frequency power influences the deposition rate，which correlates with the roughness of the film，proportion of mononuclear aromatics and bonding configuration of films surface （ways of F combination）.
Influence of duty ratio on the fabrication of a-C:H film on microshell
Authors: Zhang Bao-Ling  , He Zhi-Bing  , Wu Wei-Dong  , Liu Xing-Hua  , Yang Xiang-Dong  ,   (1)四川大学物理科学与技术学院，成都  610065；中国工程物理研究院激光聚变研究中心，绵阳  621900; (2)中国工程物理研究院激光聚变研究中心，绵阳  621900
Published: December 2020

Using low-pressure plasma chemical vapor deposition （LPPCVD）, with trans-2-butene and hydrogen as the precursors, we have successfully deposited 30 μm CH coatings on microshells in intermittent bounce mode .The surface finish was measured by atomic force microscopy （AFM）, It was found that the surface finish was improved greatly with reduced duty ratio. When the duty ratio was 1/5, the surface roughness was less than 30 nm for the 30 μm thick a-C:H film. Uniformity of a-C: H films were measured by X-rayradiography. The results showed that the influence was little of duty ratio to the uniformity of a-C: H film. When the duty ratio was 1/7, microshells could not keep on bouncing.
Study on the dielectric properties of 0.75Pb（Mg1/3Nb2/3）O3-0.25PbTiO3 ceramic under hydrostatic pressure
Authors: Zhang Chong-Hui  , Xu Zhuo  , Gao Jun-Jie  , Wang Bin-Ke  ,   (1)西安交通大学电子材料与器件研究所，电子陶瓷与器件教育部重点实验室，西安  710049; (2)西安交通大学电子材料与器件研究所，电子陶瓷与器件教育部重点实验室，西安  710049；西安工程大学理学院，西安  710048
Published: December 2020

The dielectric properties of 0.75Pb（Mg1/3Nb2/3）O3-0.25PbTiO3 （PMN-25PT） ceramic under hydrostatic pressure and pressure-induced phase transition were investigated. PMN-25PT ceramic is pure perovskite with weak relaxation at 1 bar. With increasing hydrostatic pressure，the temperature，Tm，of top dielectric constant decreases，/+{dTm}/-{dP}≈-4℃/kbar，frequency dispersion and phase transition diffuse increases，remnant polarization decreased continuously. The hydrostatic pressure dependence of dielectric constant （ε） is similar to the temperature dependence of dielectric constant. The relax ferroelectric-paraelectric （RFE-PE） phase transition was induced by hydrostatic pressure and the transition was gradual change process with stronger relaxor behavior than by temperature-induced.
Shear modulus of semi-flexible networks in two dimensions
Authors: Sun Qi-Cheng  , Zhang Guo-Hua  , Wang Bo  , Wang Guang-Qian  ,   (1)北京科技大学物理系,北京  100083; (2)清华大学水沙科学与水利水电工程国家重点实验室，北京  100084
Published: December 2020

Organized semiflexible networks composed of a large number of cross-linked quasi-linear filaments, such as actin filament semiflexible networks which determines cell stiffness and transmits force during cellular shape changes. The mechanical property of semiflexible networks plays an essential role in numerous physiological processes, and is a major research topic in the domain of complex network dynamics as well. In this work, by using the ANSYS code, we studied the shear modulus of semiflexible networks with both fixed crosslinks and free crosslinks. The scale factor L/λ, where L is the length of filament and λ the non-affine length, is appropriate for characterizing the shear modulus. The ratio of the two cases was calculated and we found a minimal value at L/λ≈1.05.
Theoretical model and numerical simulation of three-dimensional multifrequency interaction of helix traveling wave tubes
Authors: Hu Yu-Lu  , Yang Zhong-Hai  , Li Jian-Qing  , Li Bin  , Gao Peng  , Jin Xiao-Lin  ,   电子科技大学 物理电子学院,成都  610054
Published: December 2020

A three-dimensional multifrequency interaction model for helix traveling wave tubes is described. Spatial variation of the amplitude of the wave is found by field theory. With the help of paticle-in-cell （PIC） method and space harmonic current and charge expansion, the three-dimensional space charge field is found. using the code, 8—18GHz wide band TWT is simulated for different frequencies. Also, the nonlinear AM-AM and AM-PM distortion,third-order intermodulation products and fifth-order intermodulation are computed. The hot data of experiment is close to the code computation in saturation output power and output gains in the range of 8—18GHz.
Optimization of the flat-field holographic concave grating in wide spectral range
Authors: Pi Dao-Rui  , Huang Yuan-Shen  , Zhang Da-Wei  , Ni Zheng-Ji  , Zhuang Song-Lin  ,   上海理工大学光电信息与计算机工程学院,上海  200093
Published: December 2020

Based on the geometric theory of concave grating, we deduce the mathematical expressions of the meridional curve, Sagittal curve and the relational expression for the holographic flat-field image concave grating. We also propose a new optimal method in all used range for correcting the meridional and sagittal aberrations. Different from the design method using CODE V or ZEMAX, we use mathematical expression and adopt grating optimal factor instead. By fitting the meridional focusing curve and Sagittal focusing curve of concave grating, we find an image surface in theory to ensure that the meridional and also the Sagittal aberrations tend to zero, and then design and fabricate the grating based on the fitting parameters. We solve the problem that the meridional curve transcendental equation cannot solve by Matlab, and discuss the influence of two curves for different grating constants and different incidence angles. We find that the aberrations in a wide spectral range can be corrected by diminishing the incidence angle and increasing the grating scribed lines.
Generation of four-photon polarization-entangled cluster states via cross-Kerr nonlinearity
Authors: Lai Bo-Hui  , Du Gang  , Yu Ya-Fei  , Zhang Zhi-Ming  , Liu Song-Hao  ,   华南师范大学信息光电子科技学院,光子信息技术广东省高校重点实验室，量子信息技术实验室,广州  510006
Published: December 2020

We propose a scheme for generating four-photon polarization-entangled cluster states based on the cross-Kerr nonlinear interaction between field-modes. Compared with other schemes, our scheme introduces the idea of parity gate and uses the non-destructive measurement method based on homodyne detection, which is easier to implement in experiment.
Theoretical study on non-inverted wavelength conversion based on semiconductor optical amplifier and optical band-pass filter
Authors: Huang Xi  , Zhang Xin-Liang  , Dong Jian-Ji  , Zhang Yu  , Huang De-Xiu  ,   华中科技大学光电子科学与工程学院，武汉光电国家实验室 ,武汉  430074
Published: December 2020

A single semiconductor optical amplifier （SOA） assisted by optical filter is exploited to realize high-speed all-optical wavelength conversion, in which, the filter is employed to optimize output spectrum. We propose a spectrum optimizer which contains a band pass filter （BPF） and a delay interferometer （DI）. Based on this configuration, 80 Gbit/s all-optical non-inverted conversion has been numerically simulated. Furthermore, the quality of output signal has been improved greatly using genetic algorithms to optimize the parameters of the spectrum optimizer. Additionally，the effect of ultra-fast carrier dynamics in SOA on the output signal is analyzed theoretically. The dependence of the signal extinction ratio （ER） and pattern effect （PE） on variations of the BPF’s ER and DI’s ER is also studied.
Acousto-optic wavelength-tunable erbium-doped fiber ring laser
Authors: Yang Wei  , Liu Ying  , Xiao Li-Feng  , Yang Zhao-Xiang  , Pan Jian-Xuan  ,   (1)天津大学理学院应用物理系，光电信息技术科学教育部重点实验室，天津  300072; (2)天津津航技术物理研究所，天津  300192
Published: December 2020

A erbium-doped fiber ring laser, which utilizes a single-stage polarization-independent acousto-optic tunable filter by use of quasi-collinear coupling as the tuning component, is proposed and a continuously tunable lasing wavelength is realized. The filtering principle of the polarization-independent quasi-collinear filter is introduced briefly, and then the compensation of frequency-shift is analyzed. The experimental results are that the output power of the laser pumped at 13 mW is measured to be 322 μW at a lasing wavelength of 1550 nm, the threshold pump power is 7.65 mW, and the slope efficiency is 6.02%; the tuning range of 38 nm, starting from 1524.7 nm ending at 1562.4 nm, is observed.
Amplification of stimulated Brillouin scattering by collinear laser pulse series with two orthogonal polarizations
Authors: Chen Xu-Dong  , Shi Jin-Wei  , Liu Juan  , Liu Bao  , Xu Yan-Xia  , Shi Jiu-Lin  , Liu Da-He  ,   (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)北京师范大学物理系，应用光学北京市重点实验室，北京  100875；南昌航空大学无损检测技术教育部重点实验室，南昌  330063; (3)南昌航空大学无损检测技术教育部重点实验室，南昌  330063
Published: December 2020

Using the characteristic that a time delay between the signal of stimulated Brillouin scattering （SBS） and the pump beam during amplification of SBS signal is allowed, a controller is devised to control the polarizations of two pulses propagating collinearly with orthogonal polarizations. It makes the two beams have the same polarization when the SBS signal meets the pump beam. Therefore, amplification of the SBS signal is realized.
Effect of structure parameters changes on the properties of photonic crystal fiber with two zero-dispersion wavelengths
Authors: Jiang Ling-Hong  , Hou Lan-Tian  ,   燕山大学红外光纤与传感研究所，亚稳材料制备技术与科学重点实验室，秦皇岛  066004
Published: December 2020

When the hexagonal structure parameters are changed, the dispersion coefficient and nonlinear coefficient with two zero-dispersion of photonic crystal fiber as a function of wavelength is investigated from the near infrared wavelength to the range of communication band by multipole method. We compare photonic crystal fiber of hexagonal structure with that of octagonal structure, both of which have the same structural parameters. The two zero-dispersion wavelengths of photonic crystal fiber with hexagonal structure are much flatter and the nonlinear coefficient of photonic crystal fiber with hexagonal structure is significantly increased, so the photonic crystal fiber with hexagonal structure is more accessible to flattened high nonlinearity and two zero-dispersion wavelengths. It is shown from numerical results that it is possible to design photonic crystal fiber of hexagonal structure with two zero-dispersion and high nonlinear coefficient around 800 nm.
Characteristics of nano-structured photonic crystal fibers with high birefringence
Authors: Zhang Lei  , Li Shu-Guang  , Yao Yan-Yan  , Fu Bo  , Zhang Mei-Yan  , Zheng Yi  ,   (1)北京交通大学理学院，北京  100044; (2)燕山大学理学院，亚稳材料制备技术与科学国家重点实验室，秦皇岛  066004; (3)燕山大学理学院，亚稳材料制备技术与科学国家重点实验室，秦皇岛  066004；北京交通大学理学院，北京  100044
Published: December 2020

A kind of high birefringence and highly nonlinear nano-structured photonic crystal fibers （N-PCFs） is proposed. The birefringence, fundamental mode field, dispersion and nonlinear characteristics of the fiber have been studied by electromagnetic scattering theory of multipole. It is found that the birefringence becomes larger by increasing the dissymmetry level of fiber core and air holes in cladding, and the largest birefringence reaches up to 1.918×10-2. With this type of high birefringence and highly nonlinear N-PCFs, the peak of birefringence can be moved to the required wavelength by adjusting the pitch value. The non-linear coefficient of N-PCF with pitch 400 nm reaches up to 0.2 m-1·W-1 in the wavelength of 800 nm.Meanwhile, the birefringence value is also very large in the wavelength range of 750—1000　nm. A perfect combination of high birefringence and high nonlinearity is realized in N-PCF. It is useful for manufacturing new type of nano-photonic apparatus and development of integrated optics.
An all fiber multi-laser pulse generation system
Authors: Lin Hong-Huan  , Wang Jian-Jun  , Dang Zhao  , Zhang Rui  , Deng Ying  , Xu Dang-Peng  , Chen Ji  , Wang Chao  , Chen De-Huai  ,   中国工程物理研究院激光聚变研究中心，绵阳  621900
Published: December 2020

We demonstrate an all fiber multi-laser pulse generation system that can output broadband chirped pulse, nano-second shaped pulse and narrowband pump pulse for optical parametric chirped pulsed amplifiers system with precise synchronization. Yb3+-doped fiber mode-locked laser and single longitudinal oscillator are used as the optical source for the fiber system. The ultra-short pulse train generated from the mode locked fiber laser was split into two beam-lines and both were chirp-stretched to 0.9 ns. One of them was directly amplified to a magnitude of 10 μJ to provide the high-energy petawatt laser facility with seed pulse. The other was tailored by a 1.2 nm bandwidth filter to form a 140 ps unit pulse. It was then stacked in a fiber stacker and formed a 2.3 ns arbitrarily shaped pulse. The shaped pulse was amplified to 10 μJ to provide seed pulse for the pellet compression. Simultaneously, we sampled part of the ultra-short pulse train from the mode locked laser. The sampled pulse train was converted to electrical signal and phase-locked to generate trigger pulse that precisely synchronized with the mode locked pulse for an amplitude modulator. The continuous-wave laser generated from the fiber single longitudinal oscillator was tailed by the amplitude modulator and then amplified to provide seed pulse for the OPCPA system. The output of the fiber system can switch between different kinds of pulses with flexibility according to the physical experimental requirement.
Chemical vapor deposited diamond detectors for soft X-ray power measurement
Authors: Hou Li-Fei  , Li Fang  , Yuan Yong-Teng  , Yang Guo-Hong  , Liu Shen-Ye  ,   中国工程物理研究院激光聚变研究中心,绵阳  621900
Published: December 2020

A class of wide band-gap semiconductor offers an attractive alternative to Si and X-ray diode detector technologies for X-ray detection in inertia contract fusion （ICF） experiments, because diamond has high thermal conductivity, resistivity and breakdown field, fast charge collection, low leakage current, wide band-gap, low dielectric constant, large carrier drift velocity and outstanding radiation hardness. Using chemical vapor deposition （CVD）, diamond of 1 mm×1 mm×2 mm，1 mm×1 mm×3 mm was synthesized. The quality of diamond has been examined by Ramma spectrum and X-ray diffraction. And the detectors were fielded. Characteristics of these detectors have been studied on an 8 ps pulse-wide laser equipment and SGIII-prototype equipment. The results indicate that the rise time and full width at half maximum of the detector system reach 60 ps and 120 ps, respectively. The measured spectrum is consistent with the result of soft X-ray spectrometer. There is no response to 3ω0 laser for the CVD detector. The applications of CVD diamond for X-ray measurement in ICF experiments are reviewed.
Casimir force, Hamaker force, stiction and snap-back
Authors: Tian Wen-Chao  , Wang Lin-Bin  , Jia Jian-Yuan  ,   西安电子科技大学机电工程学院,电子装备结构教育部重点实验室，西安  710071
Published: December 2020

Aiming at solving the “snap back” problem in the stiction, the sine rough surface model is established. Based on the Casimir effect, the Casimir force is obtained. Based on the micro scopic Wigner-Seitz principle, the Hanaker force is derived, which includes the repulsive force. The stiction force is simulated and the two “snap back” points are found. The curve of the stiction force has two break points, which is in agreement with the experiment.
Influence of defects on the coalescence of helium in titanium: An atomistic simulation
Authors: Chen Min  , Hou Qing  ,   (1)四川大学原子核科学技术研究所，辐射物理及技术教育部重点实验室，成都  610064; (2)四川大学原子核科学技术研究所，辐射物理及技术教育部重点实验室，成都  610064；西南科技大学国防科技学院，绵阳  621010
Published: December 2020

Molecular dynamics was employed to study the migration and coalescence of He atom and He dimmer in Ti lattice which contains He-vacancy cluster. The influence of the ratio of helium to vacancy （He density） of the cluster and the He number of the cluster on coalescence of He and He-vacancy cluster in Ti lattice is studied. It is found that anisotropic diffusion is independent of the He-vacancy cluster in Ti lattice. The coalescence of helium and He-vacancy cluster is mainly along the ［001］ direction. The coalescence of He dimmer and He-vacancy cluster is faster than the coalescence of He atom and He-vacancy cluster.
First-principles study of gold p-type doping in Hg1－xCdxTe
Authors: Han Jin-Liang  , Sun Li-Zhong  , Chen Xiao-Shuang  , Lu Wei  , Zhong Jian-Xin  ,   (1)湘潭大学量子工程与微纳能源研究所，材料与光电物理学院，湘潭  411105; (2)湘潭大学量子工程与微纳能源研究所，材料与光电物理学院，湘潭  411105；中国科学院上海技术物理研究所红外物理国家重点实验室，上海  200083; (3)中国科学院上海技术物理研究所红外物理国家重点实验室，上海  200083
Published: December 2020

Using plane-wave pseudopotential methods based on the density functional theory, we have studied the structural and the electronic properties of gold doped Hg1-xCdxTe （MCT）. The results indicate that the in situ gold impurity maintains stabile bonds with the host atoms. Moreover, the in situ gold impurity creates a shallow acceptor level behaving as an efficient p-type dopant. For all mole fractions under molecular beam epitaxy （MBE） cation-rich growth condition, for 0.75＜x≤1 under MBE Te-rich growth condition, and for 0.75≤x≤1 under liquid phase epitaxy cation rich growth condition, the self-compensating effect occurs and the gold impurity cannot behave as an efficient p-type dopant in MCT.
Theoretical analysis on the improvement of p-type ZnO by B-N codoping
Authors: Deng Bei  , Sun Hui-Qing  , Guo Zhi-You  , Gao Xiao-Qi  ,   华南师范大学光电子材料与技术研究所，广州   510631
Published: December 2020

The formation of B defect, the crystal structure, formation energies, density of states and electronic structure of B-N codoped ZnO were studied using first-principles pseudo-potential approach of the plane wave based upon the density functional theory（DFT）.The study reveals that most of the B atom will present in as-doped ZnO in the form of BZn, which could result in the shrinkage of ZnO unitcell.Compared with N doped ZnO, B-N codoped ZnO has a lower formation energy, correspondingly a higher chemical stability, so its formation is more realizable. Moreover, the acceptor levels of B-N doped ZnO are shallower, resulting in a decreased ionization energy as well as a higher acceptor density.The bonding power of Zn-N is increased in as-doped ZnO, the properties of acceptors are also improved, therefore B-N codoping is expected to be a more efficient way to fabricate p-type ZnO.
Dynamic response of the coherent parallel-plate capacitor to the external field
Authors: Quan Jun  , Liu Yi-Xing  , Yu Ya-Bin  ,   (1)国防科技大学理学院，长沙  410073; (2)湖南大学物理与微电子科学学院，长沙  410082
Published: December 2020

We discuss the capacitance of a coherent mesoscopic parallel-plate capacitor based on the self-consistent theory of dynamic response for mesoscopic systems. The results show that the capacitance is a complex function of frequency which is strongly dependent on the frequency of the external field. The capacitance-frequency curve shows a significant characteristic that a peak in the imaginary part of the capacitance corresponds to the minimum in the real part, and further study shows that they are related to a plasmon-like excitation. In addition,we discuss the size effect of the capacitor, and find that the capacitance approaches geometric capacitance when the distance between two plates of the capacitor is very large.
Preparation and characterization of Sb2Te3 thermoelectric thin films by ion beam sputtering
Authors: Fan Ping  , Zheng Zhuang-Hao  , Liang Guang-Xing  , Zhang Dong-Ping  , Cai Xing-Min  ,   深圳大学物理科学与技术学院,薄膜物理与应用研究所,深圳市传感器技术重点实验室，深圳  518060
Published: December 2020

Antimony and tellurium were deposited alternatively on the substrates by ion beam sputtering with 11 periodic layers of Sb/Te deposited. The films were then annealed at the vacuum chamber. The properties of the thin films were tested by X-ray diffraction （XRD）, Hall measurement and Seebeck coefficient measurement systems. XRD results indicate that the major diffraction peaks of the film match those of Sb2Te3. The film growth is apparently at the ［101］/［012］ orientation and many Te peaks are observed. Hall measurement reveals that all the samples are p-type and the resistivities are low. The electric conductivity of the films approaches that of the bulk metal and the carrier concentration is of 1023 cm-3. Seebeck coefficient measurement shows that the samples have nice thermoelectrical properties and the seebeck coefficients are in the range of 7.8—62 μV/K. Among all, the samples annealed at 200 ℃ for 6 h have the highest seebeck coefficient of about 62 μV/K and the lowest resistivity.
Gamma radiation effect on GaN-based blue light-emitting diodes with multi-quantum well
Authors: Jin Yu-Zhe  , Hu Yi-Pei  , Zeng Xiang-Hua  , Yang Yi-Jun  ,   扬州大学物理科学与技术学院，扬州  225002
Published: December 2020

We study the irradiation effects of the GaN-based blue light-emitting diodes（LEDs） with InGaN/GaN multi-quantum well irradiated by five doses of 60Co （4×104 Ci） at room temperature. From the analyses of the characteristics of the current-voltage （I-V） relation, current-luminous flux （F-L） relation, chromatic purity, luminous intensity, luminous flux, the full width at half maximum, and the wavelength of LEDs samples before and after irradiation, we obtain the effects of γ irradiation on the devices. It shows that the consistency and uniformity of the samples become worse after irradiation. At the 20 mA working current, the luminous intensity reduces by 90% and the luminous flux falls by 40% at the maximum total dose. The quantity τ0Kγ describing the radiation hardness of the LEDs is equal to 4.039×10-7 rad·s-1, and the saturation current increases at lower positive bias （<2.6 V） with the increasing total dose.
Millimeter wave irradiation characteristics of high temperature superconductor bicrystal Josephson junction embedded in a Fabry-Perot resonator
Authors: Yue Hong-Wei  , Yan Shao-Lin  , Zhou Tie-Ge  , Xie Qing-Lian  , You Feng  , Wang Zheng  , He Ming  , Zhao Xin-Jie  , Fang Lan  , Yang Yang  , Wang Fu-Yin  , Tao Wei-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

The millimeter wave irradiation characteristics of a Tl-2212 high-temperature superconducting thin film bicrystal Josephson junction embedded in a hemispherical Fabry-Perot resonator was studied. The coupling characteristics of the bicrystal Josephson junction with the Fabry-Perot resonator have been investigated experimently, showing that it was greatly affected by the factors such as the location of the sample in the open resonator, the angle between them, the pattern of the junction and the distance between the two reflecting mirrors of the resonator. The optimized coupling between Josephson junction and applied microwave was achieved by refined adjustment of the factors. In this case, 9 orders distinct Shapiro steps were observed. Taking advantage of the Fabry-Perot resonator technique, the coupling problem between high-temperature superconducting thin film Josephson junction and applied millimeter wave was well solved, which is of significance for the research on radiation and detection of millimeter wave and terahertz wave of high-temperature superconducting Josephson junction.