bluuebunny/crossref_metadata_2025 huggingface dataset:
Radiation properties of a whispering-gallery-mode fibre laser based on skew light pumping
Authors: Zhang Yuan-Xian  , Feng Yong-Li  , Zhou Li  , Pu Xiao-Yun  ,   云南大学物理系，昆明 650091
Published: December 2020

The radiation properties of a whispering-gallery-mode （WGM） fibre laser based on skew beam pumping have been studied. It is found from experiment that when pumped by skew light along the fibre’s axis, both transverse electric wave （TE） and transverse magnetic wave （TM） exist in WGM lasing emission simultaneitly. With the increase of refractive index of cladding dye solution, the wavelength spacing between TE and TM waves of which the radial mode number and angular mode number are the same value decreases, and the central lasing wavelength of WGM bluely shifts to short wavelength direction. Based on radiation theory of WGM fibre laser and a model of four-energy levels of dye laser, the obtained experimental results are well explained.
A traceable calibration method for spectroscopic ellipsometry
Authors: Zhang Ji-Tao  , Li Yan  , Luo Zhi-Yong  ,   (1)清华大学精密仪器与机械学系，精密测试技术及仪器国家重点实验室，北京  100084; (2)中国计量科学研究院，北京  100013
Published: December 2020

A method for calibrating the spectroscopic ellipsometry by X-ray reflectivity is presented. As an indirect method，spectroscopic ellipsometry does not have the traceability because the measured film thickness is dependent on its optical constant. In contrast，at the grazing angle，the X-ray reflectivity can be used to measure the absolute thickness of thin film with sub-nanometer precision，and is independent of the optical constant. Five SiO2 films were deposited on the substrate of single crystal silicon with the thickness of 2 nm，18 nm，34 nm，61 nm，and 170 nm，respectively. The results of spectroscopic ellipsometry and X-ray reflectivity were well fitted by a liner equation with slope of 1013±0013 and its intercept was set to zero，which means this calibration method is valid for spectroscopic ellipsometry in the determination of the thickness of thin films.
Study on current distribution and radiation characteristics of plasma antennas
Authors: Wu Zhen-Yu  , Yang Yin-Tang  , Wang Jia-You  ,   西安电子科技大学微电子学院,宽禁带半导体材料与器件教育部重点实验室,西安 710071
Published: December 2020

A surface-wave driven plasma antenna has been built. An exponential model of the surface current distribution has been proposed to calculate the radiation pattern of the plasma antenna. The results show that the plasma density decreases exponentially with the axial length. The magnitude of the imaginary part of the surface wave vector shows similar exponentially decaying profile with the plasma density under normal conditions, while the real part of the wave vector remains almost constant. The surface current distribution shows a traveling wave mode with exponentially decaying magnitude. The calculated radiation pattern of a typical “8” figure fits the experimental values well using the proposed surface current distribution model. The radiation pattern is broadened when the input RF power decreases.
High-resolution electron microscopy of misfit dislocations in AlSb/GaAs（001） system
Authors: Wen Cai  , Li Fang-Hua  , Zou Jin  , Chen Hong  ,   (1)Centre for Microscopy and Microanalysis and Materials Engineering,The University of Queensland,St. Lucia Queensland 4072,Australia; (2)中国科学院物理研究所北京凝聚态物理国家实验室,北京  100190
Published: December 2020

The detailed core structures of misfit dislocations in the AlSb/GaAs（001） heterostructure system were studied by 200 kV LaB6 filament high-resolution electron microscope. In combination with image deconvolution, the［110］ images were transformed into the projected structure maps, and the image resolution was enhanced up to the information limit of the microscope. To distinguish Al and Sb atoms in the AlSb film, the image contrast change with the sample thickness was analyzed for the perfect region in deconvoluted image, and the positions of Al and Sb atoms in the dumbbells were determined based on the image contrast theory of the pseudo-weak-phase object approximation. Then the structure models of two types of misfit dislocations were constructed. As the simulated images are in good agreement with the experimental images, the AlAs type interface and the core structures of obtained Lomer and 60° misfit dislocations were determined.
Study on the removal of impurities in silicon by electrorefining
Authors: Jia Ming  , Tian Zhong-Liang  , Lai Yan-Qing  , Li Jie  , Yi Ji-Guang  , Yan Jian-Feng  , Liu Ye-Xiang  ,   中南大学冶金科学与工程学院,长沙 410083
Published: December 2020

The rapid expansion of the photovoltaic （PV） all market requires an abundant supply of silicon feedstock. A creative and simple three-layer method and apparatus have been developed for electrorefining of silicon for solar cell application. The anode is solidified from a hypereutectic solution of copper and metallurgical grade silicon. At the temperature of operation （950℃）, elements which have an electronegativity greater than that of silicon （e.g., Cu, B, P, etc.） will remain at the anode and then the Cu-Si phase can be used under certain conditions as a filter for purifying silicon with an electrorefining process. Two typical morphologies of deposit are found as coherent layer and osteoporosis layer, and deposited silicon particles with different grain size are found embedded in electrolyte. Furthermore, with increasing operation time and current density, re-combination of silicon particles is revealed which yields a larger-sized silicon ball of 1—2 cm in size. The analysis of the anode feed and refined silicon shows a remarkable reduction of B and P concentration, from 127 to 22 ppmw and 986 to 41 ppmw, respectively.
Microwave absorbing properties of composite coating by carbon nanotube and nanoscaled tetrapod-shaped ZnO
Authors: Wang Jian  , Li Hui-Feng  , Huang Yun-Hua  , Yu Hai-Bo  , Zhang Yue  ,   (1)北京科技大学材料物理与化学系,北京  100083; (2)北京科技大学新金属材料国家重点实验室,北京  100083; (3)北京科技大学新金属材料国家重点实验室,北京  100083；北京科技大学材料物理与化学系,北京  100083
Published: December 2020

Microwave absorbing coating samples were fabricated with carbon nanotube （CNT） and nanoscaled tetrapod-shaped ZnO （NT-ZnO） as the absorbents and epoxy resin as the binder. The influence of the content of CNT and NT-ZnO in the absorbing coatings on microwave absorbing property was investigated. After 3-layer coating, when the content of CNT reached 12%, NT-ZnO reached 8% and the coating thickness was 15 mm, the results showed that the minimum reflection was -2307 dB. The frequency width reached 5 GHz below -10 dB and the area density was 2 kg/m2 The microwave absorbing performance has obviously improved compared with that of the pure carbon nanotube and nano tetrapleg ZnO coating. Finally, the absorbing mechanism was discussed.
The improvement on total ionizing dose （TID） effects of the ultra-deep submicron MOSFET featuring delta doping profiles
Authors: Wang Si-Hao  , Lu Qing  , Wang Wen-Hua  , An Xia  , Huang Ru  ,   (1)北京大学微电子学深圳研究院,集成微系统重点实验室，北京  100871; (2)北京大学微电子学深圳研究院,集成微系统重点实验室，北京  100871；长春理工大学，微电子系，长春  130022
Published: December 2020

Total ionizing dose （TID） effects of the deep submicron MOSFET （metal oxide semiconductor field effect transistor） with delta doping profiles and uniform doping profiles in the channel region are analyzed in this paper. The influence of both doping profiles on the leakage current and threshold voltage is investigated. The results show that, the leakage current of MOSFET with delta doping profile is 2—3 orders lower than that with the uniform doping profile when the radiation dose is lower than 500 krad. Yet when the radiation dose is higher than 500 krad, the delta doping profile dose not show significant improvement compared with uniform doping profile as the trapped holes in the MOSFET saturate. But the threshold voltage shift is about 40 mV less than that with the uniform doping profile. Therefore, the TID effects of the deep submicron MOSFET can be improved by adopting the delta doping profile. The optimization of the delta-doping profile to further improve the TID effects is also given in this paper, which provides the guideline for the radiation hardened design.
Theoretical and experimental results of focusing performance for the parabolic compound X-ray refractive lenses
Authors: Le Zi-Chun  , Dong Wen  , Liu Wei  , Zhang Ming  , Liang Jing-Qiu  , Quan Bi-Sheng  , Liu Kai  , Liang Zhong-Zhu  , Zhu Pei-Ping  , Yi Fu-Ting  , Huang Wan-Xia  ,   (1)浙江工业大学理学院，杭州  310032; (2)中国科学院长春光学精密机械与物理研究所,长春  130033; (3)中国科学院高能物理研究所,北京  100049
Published: December 2020

The parabolic compound X-ray refractive lenses are a kind of novel optical components, especially suitable for hard X-rays. Due to their parabolic profiles they are free of spherical aberration and are proper devices for sub-micrometer focusing and imaging. The focusing performance of the parabolic compound X-ray refractive lenses is studied theoretically and experimentally in this paper. Firstly, the derivation of the exact focal length formula using matrix optics method and a criterion of the thin lens approximation are described. And the intensity distribution near focus, limiting focal spot size, effective aperture and transmittance are deduced based on the diffraction theory. Several parabolic compound X-ray refractive lenses with PMMA material were fabricated by means of deep X-ray lithography. Then the X-ray microbeam experimental system was built on the 4W1A beamline of Beijing Synchrotron Radiation Facility （BSRF） based on the parabolic compound X-ray refractive lenses we fabricated. The focusing performances of three PMMA parabolic compound X-ray refractive lenses were measured and analyzed under 8 keV monochromatic X-rays. According to the experimental results, it is concluded that the PMMA parabolic compound X-ray refractive lenses promises good hard X-ray focusing performance.
Research on prediction model of radiation effect for complementary metal oxide semiconductor devices at low dose rate irradiation in space environment
Authors: He Bao-Ping  , Yao Zhi-Bin  ,   西北核技术研究所,西安  710613
Published: December 2020

A new model is presented to predict the radiation response for complementary metal oxide semiconductor（CMOS）devices at low dose rate in space environment. In comparison with the linear system response theory model, the prediction results for CMOS devices at low dose rate radiation by using the new model are more close to actually experiment data, and the experimental results for different dose rate of radiation verify the accuracy of the model. Finally, the radiation effects on sensitive parameters of CMOS devices at low dose rate in space environment are predicted by making use of the new model.
A novel nanometer CMOS interconnect optimal model with target delay and bandwidth constraint
Authors: Zhu Zhang-Ming  , Hao Bao-Tian  , Li Ru  , Yang Yin-Tang  ,   西安电子科技大学微电子研究所，西安  710071
Published: December 2020

Optimization of interconnect power and repeater area is an important issue in the design of nanometer CMOS ICs. Based on RLC delay model, the paper proposes a new optimal model to minimize power and area overhead with constraints of target delay and target bandwidth. The proposed model is verified at 90 nm, 65 nm and 45 nm CMOS technology. Experimental result shows that the proposed model can save an average power consumption of 46% and 61% and can save an average area of 65% and 83% at the expense of 1/3 and 1/2 bandwidth, respectively. The proposed optimal model can be used in computer-aided design for nanometer CMOS system-on-chip.
Stability of equilibrium for the autonomous generalized Birkhoffian system
Authors: Zhang Yi  ,   苏州科技学院土木工程学院，苏州  215011
Published: December 2020

The stability problem of equilibrium for a generalized Birkhoffian system is studied. The equations of equilibrium for the autonomous generalized Birkhoffian system are established. The equations of first approximation of the system are given, and the criterion of stability for equilibrium state of the system is established by using the Liapunovs first approximation theory. The Liapunovs function is constructed, and the criterion of stability for equilibrium state of the system is established by using the Liapunovs direct method. Some examples are given to illustrate the application of the results.
The study of the influence mechanism of platinum group and transition metals on the passivation of Ti alloys
Authors: Zhang Guo-Ying  , Yang Li-Na  , Zhang Hui  , Wu Jian-Jun  ,   (1)沈阳师范大学物理科学与技术学院，沈阳  110034; (2)沈阳师范大学物理科学与技术学院，沈阳  110034；中国科学院金属研究所钛合金研究部,沈阳  110016
Published: December 2020

The electronic structure of Ti alloys has been calculated by the recursion method. Alloying elements Ni, Co, Pt, Ru and Ir were confirmed to segregate on the surface of Ti alloys. Ni and Co atoms form atomic clusters, while Pt, Ru and Ir atoms form the ordered phase with Ti atoms. The microcells are formed between the area with alloying atomic clusters and the region without alloying elements. Ti is dissolved preferentially in the corrosive media, and the enrichment layer on the surface of Ti alloys is formed by the remaining insoluble grain of the alloying elements. The enrichment layer of alloying atoms serves as the electrocatalytic surface, which facilitates the passivation of Ti alloys and improves the corrosion resistance. The co-added alloy elements, such as Ru-Ni, Ru-Ir, Ru-Mo and Ru-W, have the same effect as adding the noble metals （such as Pt）.
Structure and optical properties of ZnO/MgO multi-quantum wells deposited on oxidated sapphire substrate
Authors: Luan Tian-Bao  , Liu Ming  , Bao Shan-Yong  , 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

ZnO/MgO multi-quantum wells with modulation structure are grown on oxidated Al2O3 （0001） substrates using radio-frequency reactive magnetron sputtering method. X-ray reflectivity and X-ray diffraction measurement，electronic probe，atom force microscopy，transmission spectrum and PL spectrum are used to characterize the samples. The XRD scan and phi-scan results show the films are highly （001） textured and have epitaxial relationship with the substrates. The width of quantum well is determined to be between 838 nm and 2178 nm by XRR and EPMA. The AFM results show that the RMS roughness of the MQWs increases from 64 nm to 212 nm with the decrease of period of modulation. Low temperature PL spectrum shows the peak can be assigned to the radiative recombination of bound excitons，and the activation energy is estimated to be about 30 meV. The emission due to spatially separated carriers caused by quantum-confined Stark effect is also found in the spectrum of sample with smaller well width.
First-principles calculation of structural stability and electronic properties of ZnO atomic chains
Authors: Wang Zhi-Gang  , Zhang Yang  , Wen Yu-Hua  , Zhu Zi-Zhong  ,   (1)乐山师范学院物理与电子工程学院，乐山 614004；厦门大学物理系，厦门大学理论物理与天体物理研究所，厦门 361005; (2)厦门大学物理系，厦门大学理论物理与天体物理研究所，厦门 361005
Published: December 2020

First-principles plane wave pseudopotential method based on the density functional theory is used to study the structural stability and electronic properties of ZnO atomic chains. The results show that ZnO molecules can form atomic chains with linear，ladder and double ladder one-dimensional stable structures whereas the zigzag chain is unstable. Our calculations also show that the stable chains exhibit indirect band gap characteristics while the unstable zigzag chain exhibits that of metal-like band gap.
Influence of field annealing on giant magneto-impedance effect of Co-based melt extraction amorphous wires
Authors: Zhang Shu-Ling  , Sun Jian-Fei  , Xing Da-Wei  ,   哈尔滨工业大学材料科学与工程学院，哈尔滨 150001
Published: December 2020

In order to investigate the influence of anneal treatment on the Co-based melt extraction wires, the soft magnetic properties and giant magnet-impedance （GMI） effect of the annealed Co75Fe40Si8B12Nb1 wire are investigated. Samples are prepared using melt extraction technology in vacuum and annealed at 450℃ without magnetic field or with miagntic field either longitudinal or transverse to the axis of wire of strength from 500 Oe to 4000 Oe，respectively. The magnetic softness and GMI response are measured using HP4192 Impedance Analyzer and Lakeshore7407 VSM. Test results show that the circular anisotropy and GMI response are reduced after longitudinal field anneal treatment. GMI profiles are single-peaked and the maximum impedance ratio ΔZ/Z is 131% and field sensitivity is 7%/Oe. The circular permeability and GMI response are improved after transverse field anneal treatments because of the increased circular anisotropy. At higher frequencies，the GMI profiles change from single-peaked to two-peaked after being annealed in strong transverse field. The circular permeability is increased and GMI effect gets stronger with the increase of current frequency and anneal field. The largest impedance ratio of 190% with a field sensitivity of 26%/Oe is obtained for the Co-based transverse field annealed wires at 10 MHz. The correlations between the circular permeability，the GMI effect and the current frequency are discussed in the light of a skin effect model.
Preparation，structure and ferromagnetic properties of BiFeO3 nano-power
Authors: Zhang Huan  , Liu Fa-Min  , Ding Peng  , Zhong Wen-Wu  , Zhou Chuan-Cang  ,   北京航空航天大学物理科学与核能工程学院，北京 100191
Published: December 2020

The BiFeO3 nano-powder has been synthesized by sol-gel method. The structure and morphology of BiFeO3 nano-powder have been characterized by X-ray diffraction （XRD），scanning electron microscopy （SEM） and high resolution transmission electron microscopy （HRTEM）. The results showed that the samples sintered at 700℃ for 2 h or 25 h is in the formed of pure BiFeO3 with the grain size about 30 nm，and the structure is hexagonal of R3-m［166］ space group with lattice constants a=b=05580 nm，c=06939 nm，and the spacing of （101） and （110） are about 0396 nm and 0273 nm，respectively. The room temperature magnetic properties of samples have been measured on vibrating sample magnetometer （VSM）. It was showed that the BiFeO3 nano-powder gives a complete hysteresis loop，which means that BiFeO3 nano-powder possesses weakly ferromagnetic at room temperature，its coercive force （Hc） could reach to over 700 Oe，and the magnetic mechanism comes from the double exchange of Fe3+-O-Fe2+. Moreover，with the increase of the sintering time，the grain size is influenced；the saturation magnetization （Ms） has a small change，however，the coercive force （Hc） of the BiFeO3 nano-powder decreased obviously.
Finite elements micromagnetism simulation on the dynamic reversal of magnetic moments of Co nanowires
Authors: Lu Hai-Peng  , Han Man-Gui  , Deng Long-Jiang  , Liang Di-Fei  , Ou Yu  ,   电子科技大学微电子与固体电子学院，电子薄膜与集成器件国家重点实验室，成都 610054
Published: December 2020

The magnetization reversal processes of cobalt nanowires under different constant external magnetic fields have been studied by using the finite element micromagnetism simulation approach. The results show that magnetic domains with opposite magnetizations will be formed at one end of nanowires with a diameter of 10 nm after a nucleation time. The domain wall is classified as a transverse wall，which can be driven to move with a constant velocity by a constant external applied field from one end to the other. The velocity of domain wall is linearly dependent on the magnitude of external applied magnetic field. When H is 1000 kA/m，it is found that two head-to-head domains are found at both ends of nanowires. The calculation results show that the domain wall moves a constant distance during a period in which the direction of any magnetic moment rotates a cycle，which is independent of the magnitude of applied magnetic field.
Study of crack healing effect in dimethyl phthalate crystals by mechanical spectroscopy
Authors: Zhou Heng-Wei  , Wang Li-Na  , Guo Xiu-Zhen  , Wu Na-Na  , Zhang Li  , Zhang Jin-Lu  , Huang Yi-Neng  ,   (1)伊犁师范学院新疆凝聚态相变与微结构重点实验室，伊宁 835000; (2)伊犁师范学院新疆凝聚态相变与微结构重点实验室，伊宁 835000；南京大学物理系国家固体微结构重点实验室，南京 210093
Published: December 2020

The recently developed method to detect the stress-cracking and crack healing of glasses in real-time （called the RMS-CH in short，Wu et al.，Appl. Phys. Lett. 92，011918-1（2008）） is applied to the detections of crystals. The experimental results of dimethyl phthalate crystal indicate that，under the condition of constant heating rate：1） the crack-healing rate shows a sharp peak as a function of temperature，the peak temperature can be taken as the characteristic temperature Tcch of the crack-healing ，and Tcch=206 K；2） the peak is not symmetric，and the low temperature side is wider than the high temperature side，which means that the crack-healing has started at lower temperatures and the amount of healing below Tcch is more than that above Tcch. This behavior is similar to that in glasses，but Tcch is higher than that of glassy state. Moreover，Tcch is much lower than the melting point of the crystal，which indicates that the crack-healing mechanism is quite different from that of recrystallization. We would like to point out that two dynamical loss peaks related to the crack-healing process are observed for the first time，which will be helpful to the understanding of the mechanisms. The above results also show the feasibility and validity of the RMS-CH method to investigate the stress-cracking and crack-healing in crystals as in glasses.
Vibration energy harvester based on magnetoelectric transducer
Authors: Dai Xian-Zhi  , Wen Yu-Mei  , Li Ping  , Yang Jin  , Jiang Xiao-Fang  ,   重庆大学光电工程学院，教育部光电技术及系统重点实验室，重庆  400044
Published: December 2020

An energy harvester is presented to scavenge energy from ambient vibrations using magnetostrictive/piezoelectric laminated magnetoelectric （ME） transducer. A cantilever beam is employed as the vibration sensitive element of the harvester，and a magnetic circuit made up of four NdFeB magnets is placed on the free end of the beam. Since the magnetic circuit produces a concentrated flux gradient in the air gap，the ME transducer can induce large magnetic field variations in the low level vibration，thus high output power can be obtained. Based on the equivalent magnetic charge theory，the magnetic field distribution of the air gap and the magnetic force of the magnetic circuit are analyzed，and the nonlinear vibration performance of the harvester is studied using the Lindstedt-Poincaré method. The mechano-magneto-electric performance of the harvester at resonance is analyzed by combining the vibration equation of the harvester with the magnetoelectric characteristics of the ME transducer. The experimental results verified the analytical results，and a prototype produces a power of 1124 μW for an acceleration of 05g at its resonant frequency of 33 Hz.
Instability and interaction of the nonlinear solitary waves in two-temperature-ion dusty plasma
Authors: Zhong Sheng-Ren  ,   武威职业学院工程技术系，武威  733000
Published: December 2020

For nonlinear dust acoustic waves in unmagnetized dusty plasma containing cold dust grains and isothermal electrons and ions, small but finite amplitude nonlinear waves are governed by the Korteweg de Veries (KdV) equation. For weakly two-dimensional dust acoustic solitary waves in a dusty plasma with variable dust charge and two-temperature ions, we obtain a Kadomtsev-Petviashvili equation under higher order transverse disturbances for this system. The interactions between two solitons and three solitons propagating in arbitrary directions are investigated. It is found that the maximum amplitude in the interaction region between two same——amplitude solitons is about four times that of a single soliton, while for three solitons the maximum amplitude is nine times that of a single soliton. It suggests that the transverse perturbations for the weakly nonlinear solitary waves in dusty plasma with variable dust charge and two-temperature ions are stable.
Correlated tunneling of cold atoms in double-well potential
Authors: Cao Hui  , Zhao Qing  ,   北京理工大学理学院物理系，北京  100081
Published: December 2020

The tunneling phenomena of cold atoms in double-well with different interaction (U) and tunnel coupling (J) were studied. Experiments cannot be interpreted completely by a two-site Bose-Hubbard model. Thus, a new model was introduced, in which the ground state and the first excited state of the double-well were used as state bases. The expression of Hamiltonian was derived under the new model, which explains the reason why the parameter isnot consistent with the experiment from a two-site Bose-Hubbard model. Furthermore, we figured out the fluctuation of entanglement degree of the atoms in the double-well, and directly described the whole process of tunneling with the population of particles in the three states.
Selective automatic repeat quantum synchronous communication protocol based on quantum entanglement
Authors: Zhou Nan-Run  , Zeng Bin-Yang  , Wang Li-Jun  , Gong Li-Hua  ,   南昌大学电子信息工程系，南昌  330031
Published: December 2020

From the classical selective repeat ARQ (Automatic Repeat-reQuest) protocol, a selective repeat ARQ quantum synchronous communication protocol in data link layer is presented by utilizing the intrinsic characteristics of quantum mechanics. The proposed protocol divides the link into the preparation and the send stages, where the message is sent via classical channel and the preparation and distribution of EPR (Einstein-Podolsky-Rosen) pairs are supposed to be accomplished at the preparation stage. The performances of several protocols in data link layer are compared and analyzed from the aspects of throughput and utilization ratio of the channel. It is shown that the proposed protocol enhances the maximum throughput and the utilization ratio of the channel effectively and improves the performance of the selective repeat ARQ protocol for date link layers. The proposed protocol is of great significance in military communications.
Experimental study of diffusion-induced Ramsey narrowing in time domain
Authors: Luo Xiao-Ming  , Chen Li-Qing  , Zhong Zhi-Ping  , Jiang Shuo  ,   (1)清华大学物理系，北京 100084; (2)中国科学院研究生院物理学院，北京 100049
Published: December 2020

基于Duan-Lukin-Cirac-Zoller(DLCZ)方案，在时域上研究了扩散诱导的Ramsey压窄. 以87Rb热原子系综为研究对象，观测到缓冲气体，激光束尺寸和镀石蜡Rb池均可以导致Ramsey压窄现象. 实验结果和文献中重复相互作用模型预期的一致.
Fermion tunnels at cosmological horizon of higher dimensional de Sitter space time
Authors: Lin Kai  , Yang Shu-Zheng  ,   西华师范大学理论物理研究所，南充 637002
Published: December 2020

Using semiclassical approximation method, the fermion tunnels at cosmological horizon of higher dimensional de Sitter and Schwarzschild de Sitter space-times are researched in this paper. In our work, the Dirac equation, which describes the property of 1/2 spin particles, is simplified, and then the semiclassical Hamilton-Jacobi equation is obtained via the condition that there are non-trivial solutions of Dirac equation. The research has been simplified greatly, and the Hawking temperature and tunneling rate at cosmological horizon of static higher dimensional de Sitter space time is gotten finally.
Time dependence of information entropy of a dynamical system driven by quasimonochromatic noise
Authors: Guo Yong-Feng  , Xu Wei  , Li Dong-Xi  , Wang Liang  ,   西北工业大学应用数学系，西安  710072
Published: December 2020

The quasimonochromatic noise (QMN) is the “truly colored” noise, and in this paper the time derivative of entropy for a dynamical system driven by QMN is studied. The dimension of Fokker-Planck equation is reduced by way of linear transformation. The exact time dependence of the entropy is calculated based on the definition of Shannon’s information entropy. The relationship between the properties of QMN and dissipative parameters and their effect on the entropy is also discussed.
Analysis of symmetrical dynamic phenomenon of peak and valley current-mode controlled switching DC-DC converters
Authors: Zhou Guo-Hua  , Xu Jian-Ping  , Bao Bo-Cheng  ,   (1)南京理工大学电子工程系，南京 210094；江苏技术师范学院电气信息工程学院，常州 213001; (2)西南交通大学电气工程学院，成都 610031
Published: December 2020

Peak current and valley current controlled switching DC-DC converters show symmetrical dynamic phenomenon within a wide circuit parameter range. The unified discrete iterative map model of peak current and valley current controlled buck, boost, and buck-boost converters is established, and the unified piecewise smooth iterative map and their corresponding characteristic equations are also derived. The forward and inverse bifurcation diagrams and Lyapunov exponent spectrums with duty ratio as parameter are obtained by numerical simulation. The research results indicate that the bifurcation diagrams and Lyapunov exponent of peak and valley current-mode controlled switching converters show symmetrical dynamic phenomenon corresponding to a symmetrical point or a symmetrical axis. The numerical simulation results are verified by the time-domain simulation, which further indicates that with the duty ratio varying, the peak and valley current-mode controlled switching converter reveals a symmetrical dynamic phenomenon, or a symmetrical dynamic phenomenon accompanying an asymmetrical dynamic phenomenon, or an asymmetrical dynamic phenomenon.
Experimental study of generalized synchronization of a time-delay chaotic system
Authors: Chen Ju-Fang  , Tian Xiao-Jian  , Shan Jiang-Dong  ,   (1)吉林大学电子科学与工程学院，长春 130012; (2)吉林大学电子科学与工程学院，长春 130012；东北师范大学物理学院，长春 130024
Published: December 2020

A two-dimensional time-delay chaotic system is designed and realized in an electronic circuit based on its dynamical behavior. Then a generalized synchronization chaotic system is designed by linear transformation method. The generalized synchronization condition is obtained by mathematical analysis, and generalized synchronization is realized in an electronic circuit. The results of numerical calculation conform the exactness and validity of theoretical analysis and circuit design.
Pseudo-random sequence generating method based on LFSR and chaotic system
Authors: Zhang Xue-Feng  , Fan Jiu-Lun  ,   西安邮电学院信息与控制系,西安 710061
Published: December 2020

A cyclic iteration structure pseudo-random sequence generating method based on combined LFSR and chaotic systems is presented. Firstly, a choice function is chosen based on LFSRs computing result, and the selected chaotic function is used for generating the corresponding chaotic sequence by using iterative computation. The chaotic sequence is processed by binary system transformation, and the generated binary sequence is output as the end pseudo-random sequence. At the same time, the generated binary sequence is used as feedback value and operates with the LFSRs feedback value, the corresponding result is taken as the final feedback of LFSR. This process can achieve random perturbation of LFSR. And a real number pseudo-random sequence generating method is also presented. Performance of pseudo-random sequence generated by using our method is also analyzed by experiment, and simulation results show that the generated sequences have qualities of randomicity and security.
Microcosmic mechanism of spiral wave’s instability in excitable medium
Authors: Deng Min-Yi  , Tang Guo-Ning  , Kong Ling-Jiang  , Liu Mu-Ren  ,   广西师范大学物理科学与技术学院,桂林  541004
Published: December 2020

The instability of the spiral wave in an excitable medium is investigated by using the lattice Boltzmann method. The velocity distribution of the system are obtained by computer simulation, and discussed in connection with the pattern and the tip trajectory of the spiral wave. We find that the velocity of the particle at the rotating center of spiral wave changes periodically, while the change of this particles velocity is quickened and then becomes random when the spiral wave becomes unstable, which leads to the random decomposition of the velocity group and random distribution of velocity. The system falls into the spatiotemporal chaos finally.
Energy selective electron heat pump with transmission probability
Authors: He Ji-Zhou  , He Bing-Xiang  ,   南昌大学物理系,南昌 330031
Published: December 2020

The electron transport through an energy transmission spectrum between two reservoirs with different temperatures and chemical potentials is studied. The heat flow carried by the electrons is obtained. Taking into account the radiative heat leaks between the two electron reservoirs, the performance parameters of the heat pump are derived by numerical calculation. The performance characteristic curves of the heat pump are plotted. The influence of the heat leaks, the position of resonance energy level and the width of the level on the operation performance of the heat pump is analyzed. When the width of resonance energy level is infinitely small, the coefficient of performance may reach the value of Carnot heat pump.
Spectroscopy processing for the NO measurement based on the room-temperature pulsed quantum cascade laser
Authors: Tang Yuan-Yuan  , Liu Wen-Qing  , Kan Rui-Feng  , Zhang Yu-Jun  , Liu Jian-Guo  , Xu Zhen-Yu  , Shu Xiao-Wen  , Zhang Shuai  , He Ying  , Geng Hui  , Cui Yi-Ben  ,   中国科学院安徽光学精密机械研究所环境光学与技术重点实验室，合肥 230031
Published: December 2020

The intra-pulse spectroscopy based on room-temperature pulsed quantum cascade(QC) lasers was introduced. With a room-temperature pulsed QC laser centered at 1904 cm-1, the sample NO gas has been detected.The least-squared algorithm of baseline fitting and concentration retrieving method were introduced for the single line spectroscopy detection, and the gas concentration can be calculated with scan integration and the corresponding values from HITRAN04 database by direct-absorption technique, without calibration. The detection limit was obtained by analyzing the residual of the absorption spectroscopy as 34 ×10-6m.
Optical model potential effect in (e，2e) collisions of argon
Authors: Hu Xiao-Ying  , Zhou Ya-Jun  ,   (1)长春大学理学院，长春  130022; (2)吉林大学原子与分子物理研究所，长春  130012
Published: December 2020

We modify the distorted wave Bohn approximation method (DWBA) by introducing optical model potential into the distorted potential of DWBA in this paper.The triple differential cross section of the argon 2p orbital in a coplanar asymmetric geometry has been calculated，calculations using the modified DWBA method show that the optical model potential effects play an important role in the ionization of the argon 2p shell.
A modificatory algorithm for electrically thin dispersive layers base on shift operator finite-difference time-domain method
Authors: Wei Bing  , Dong Yu-Hang  , Wang Fei  , Li Cun-Zhi  ,   西安电子科技大学物理系，西安 710071
Published: December 2020

A novel technique for treating electrically thin dispersive layer with the finite difference time domain (FDTD) method is introduced. The proposed model is based on modifying the node update equations to account for the layer, where the electric and magnetic flux densities are locally averaged in the FDTD grid. Then, based on the characteristics that the complex permittivity and complex permeability of three kinds of general dispersive media model, i.e. Debye model, Lorentz model, and Drude model, may be described by rational polynomial fraction in jω, the shift operator method is then applied to obtain the recursive formulation for D and E, B and H available for FDTD computation is obtained. The model is validated with several numerical examples. The computed results illustrate the generality, memory and time step economy and the precision of presented scheme.
Algorithm of the non-interpolation wave-front reconstruction of the color digital holography
Authors: Li Jun-Chang  , Fan Ze-Bin  ,   昆明理工大学理学院,昆明  650093
Published: December 2020

In the research of the color digital holography and digital holography measurement with multi-wavelength illumination, how to avoid the interpolation error in the wave-front reconstruction with variable magnification is an important subject to be studied. Since the Fresnel diffraction integral can be expressed as Fourier transformation as well as convolution form, there are two reconstruction approaches, one is the relay algorithm which divides the reconstruction distance into two parts, the other is the convolution algorithm which uses the spherical wave as reconstruction wave. In this paper, the two algorithms are theoretically analyzed and experimentally studied, and the condition satisfying the sampling theorem for the reconstruction calculation is discussed. The results show that the convolution approach satisfies the sampling theorem more readily, while higher quality reconstructed object wave field can be obtained with the convolution approach.
Simulation and fabrication of flexible cantilever electromagnet actuated optical switch
Authors: Xu Da-Wei  , Liang Zhong-Zhu  , Liang Jing-Qiu  , Li Wei  , Li Xiao-Qi  , Sun Zhi-Dan  , Wang Wei-Biao  ,   (1)中国科学院长春光学精密机械与物理研究所应用光学国家重点实验室,长春 130033; (2)中国科学院长春光学精密机械与物理研究所应用光学国家重点实验室,长春 130033；中国科学院研究生院，北京 100049
Published: December 2020

A kind of flexible cantilever beam electromagnetic optical switch which is used in the wave length channel selection system was designed and fabricated. It was manufactured by micro-opto-electromechanical system technology and composed of a plane circular coil in flexible polyimide cantilever beam, a cylindrical permanent magnet，the substrate and a reflector prism with two reflecting surfaces. The switch′s motion depends on the current direction in the coils. The simulation of force between the coils and the permanent magnet was proceeded by finite element method. In the same way, the relationship between cantilever’s deflection and restoring force, and electromagnetic force were obtained. The switch′s actuation performance was tested and the results indicate that deflection of the cantilever is 0925 mm with 015 A current input，which satisfies the need of the wave length channel selection system of changing the propagation direction of the optical beam.
Study and design of a quasi-optical mode converter for W-band whispering-gallery mode gyrotron
Authors: Wang Bin  , Du Chao-Hai  , Liu Pu-Kun  , Geng Zhi-Hui  , Xu Shou-Xi  ,   (1)中国科学院电子学研究所，中国科学院高功率微波源与技术重点实验室，北京 100190; (2)中国科学院电子学研究所，中国科学院高功率微波源与技术重点实验室，北京 100190；中国科学院研究生院,北京 100049
Published: December 2020

A quasi-optical mode converter for a whispering-gallery mode gyrotron，consisting of a Vlasov helically-cut launcher and two curved-mirror reflectors, is studied and designed. Firstly, the operation mechanism of the Vlasov type quasi-optical mode converter is investigated using geometric optics theory. And then, applying the aperture field integration and the surface current source integration of the vector diffraction theory, a numerical simulation code is programmed. Finally, the code is used to study a quasi-optical converter system of a W-band whispering-gallery mode gyrotron, and the operation mechanism of the mode conversion in the converter is revealed in detail. Numerical results indicate that the TE12,2 whispering-gallery mode inside the W-band gyrotron is converted into a highly Gaussian-like beam at the output window.
Numerical simulation of light intensity distribution in the vicinity of three-dimensional Hertzian conical scratch on fused silica subsurface
Authors: Hua Jin-Rong  , Zu Xiao-Tao  , Li Li  , Xiang Xia  , Chen Meng  , Jiang Xiao-Dong  , Yuan Xiao-Dong  , Zheng Wan-Guo  ,   (1)电子科技大学物理电子学院，成都  610054; (2)电子科技大学物理电子学院，成都  610054；中国工程物理研究院激光聚变研究中心，绵阳  621900; (3)中国工程物理研究院激光聚变研究中心，绵阳  621900
Published: December 2020

The main factor of laser induced damage is the modulation caused by the scratch in the subsurface of the fused silica. The three-dimensional Hertzian conical scratch (HCS) model on the exit surface is establised in this article. Three-dimensional finite-difference time-domain method is used to calculate and simulate the electric field intensity distribution in the vicinity of HCS. The effects of depth, radius and gradient angle of the HCS on incident light field modulation are analyzed, respectively. The results show that the electric field enhancement in the center of HCS is the largest. This area is apt to be damaged. The maximal electric field intensity in the fused silica will be enhanced as the depth of the HCS changes from λ to 19λ/2. The fused silica is liable to be damaged while the radius of HCS is below 15λ. When the radius is larger than 175λ, the maximal electric fields in the fused silica tend to be 2.5 V/m. And the maximal electric fields are independent on the radius. The effect of light intensity enhancement is more obviously when total internal reflection occurs between internal interface of HCS and the rear surface of fused silica.
The mode and defect mode of electromagnetic wave in rectangular doped photonic crystal
Authors: Liu Qi-Neng  ,   重庆工商大学计算机科学与信息工程学院,重庆 400067
Published: December 2020

The mode condition of electromagnetic wave is obtained by making use of restriction condition of horizondal direation electromagnetic wave in one-dimensional rectanglular doped photonic crystal and the mode characteristics of electromagnetic wave is studied. The response of the defect mode versus mode quantum number and length of the rectangle is calculated by the characteristic matrix method. Some new defect mode structure of rectangular doped photonic crystal is obtained.
Design, fabrication and test of X-ray freestanding transmission gratings
Authors: Ma Jie  , Xie Chang-Qing  , Ye Tian-Chun  , Liu Ming  ,   中国科学院微电子研究所，纳米加工与新器件集成研究室，北京 100029
Published: December 2020

The diffraction efficiency of freestanding x ray transmission gratings is discussed in relation to the wavelength and grating period using both scalar diffraction theory and rigorous coupled wave analysis, and the grating design is accordingly optimized. A gold freestanding x ray transmission grating with period of 300 nm, line/period ratio of 055, thickness of 200 nm a size of 1 mm ×1 mm and fractional grating area of 65% is fabricated. The absolute diffraction efficiency of the fabricated grating was tested at the National Synchrotron Radiation Laboratory in the wavelength region of 55— 38 nm. The test result shows that the grating has a maximum efficiency of nearly 10%. The grating also shows a stable diffraction efficiency in the wavelength region from 15 nm to 35 nm.
Dispersion characteristic of a new hybrid cladding photonic crystal fiber
Authors: Cui Yan-Ling  , Hou Lan-Tian  ,   (1)燕山大学红外光纤与传感研究所，秦皇岛 066004; (2)燕山大学红外光纤与传感研究所，秦皇岛 066004；燕山大学亚稳材料制备技术与科学重点实验室，秦皇岛 066004
Published: December 2020

Based on multi-pole method theory, a kind of hybrid cladding photonic crystal fiber（PCF） is designed. It has been shown theoretically that it is possible to obtain fiattened dispersion charactor of dispersion absolute value 125 ps·km-1·nm-1 within the wave band of 144 μm to 20 μm by altering four structure parameters of the five-ring hybrid cladding in the PCF (namely the diameter of the inner ring hole, the diameter of the outer four ring holes, the pitch of the hexagon and the pitch of the octagon). Moreover, value simulation results show that in the PCF low confinement loss of 0005 dB/km in the 144—20 μm wavelength range can be achieved.
Experimental research on the droplet impacting on the liquid film
Authors: Guo Jia-Hong  , Dai Shi-Qiang  , Dai Qin  ,   上海大学上海市应用数学和力学研究所，上海  200072
Published: December 2020

The flow phenomena such as spray，splash and especially the bell-like spray happening after a droplet impacts on the liquid film are observed in experiment. The relationship between the flow phenomena and the diameter and speed of the droplet, and the viscosity, the surface tension and the thickness of the film are probed. The condition for bell-like spray brought about after the collision of the droplet on the film is discussed.
Experimental study on mode and mechanism of multi-pulse atmospheric-pressure glow discharges
Authors: Hao Yan-Peng  , Yang Lin  , Tu En-Lai  , Chen Jian-Yang  , Zhu Zhan-Wen  , Wang Xiao-Lei  ,   华南理工大学电力学院，广州 510640
Published: December 2020

Multi-pulse atmospheric-pressure glow discharges between two slightly unparallel electrodes were carried out in helium. The mode of discharge was investigated using an intensified charge-coupled device camera. The discharge current through gas gap and surface charge on the solid dielectric barrier were calculated. Based on analysis of surface charge on the solid barrier, space charges in gas gap, applied voltage across electrodes and field strength in gas gap, the formation mechanism of multi-pulse discharge was discussed. The discharge evolution pictures show that discharge is generated at the narrower side. At the other side, discharge is also generated at the first current peak. Physical process of the first pulse of atmospheric-pressure glow discharge in helium starts from a Townsend discharge leading to a glow discharge, and that of each subsequent current pulse is a glow discharge. Between two consecutive current pulses, a faint glow discharge is maintained in the gas gap. Theoretical analysis shows that multi-pulse discharge is a result of co-evolution of both surface charge as well as space charge and applied voltage, and the Townsend discharge does not appear during current pulse sequence of the same half cycle, except for discharge inception.
Nonlinear analysis on electron beam current in cylindrical waveguide
Authors: Liu Jing  , Shu Ting  , Li Zhi-Qiang  ,   国防科技大学光电科学与工程学院，长沙  410073
Published: December 2020

The space-charge-limited currents of both solid electron beam and annular electron beam in cylindrical waveguide are derived from the nonlinear Poisson equation for potential in the region of electron beams. Corrections for the transverse motion of electrons are made to the solution, which bring more consistent with the results from PIC simulations. Though numerical computation, it is showed that electrons located along the axis and by outer radius of solid and annular electron beams respectively and electrons standing near to the outside of the beam has larger axial velocity than these inside. This approach is available for analyzing the characteristics of electron beam transporting in high power microwave generator with other configuration waveguide.
A novel configuration of vircator with coaxial waveguide
Authors: Liu Jing  , Shu Ting  , Li Zhi-Qiang  ,   国防科技大学光电科学与工程学院，长沙 410073
Published: December 2020

A novel configuration of vircator with coaxial waveguide generated by annular electron beam under low guiding magnetic field is presented and the 25-D particle-in-cell simulations are carried out using KARAT code. We obtain High power microwave with average power of 27GW, frequency of 38GHz, of which the beam-to-wave power efficiency and dominant mode are 12 % and TEM mode, respectively.
Preliminary research on Poisson-line alignment technique
Authors: Zhao Zong-Qing  , Hao Yi-Dan  , Wang Feng  , Zhang Ying  , Wang Fang  , Yuan Yong-Teng  , Ding Yong-Kun  ,   中国工程物理研究院激光聚变研究中心，绵阳  621900
Published: December 2020

Poisson line technique is a method of generating a straight line by diffraction for high precision alignment，which can keep the center of Poisson spot in this line at long distances (several tens or hundreds of meters). Numerical simulation and experimental demonstration are proposed to research this technique. The intensity of the line increases asymptotically to the incident intensity as distance from the disk increases. The diameter of the line increases as the distances from the disk increases. Whereas it decreases as the diameter of the disks increases. The direction of the line is parallel to laser beam and propagates through the center of the disk，which is sensitive to center excursion and insensitive to the incline of the disk. Poisson line is sensitive to 10 μm excursion in simulation. And Poisson line technique can adjust 50 μm center excursion at long distance in experimental demonstration.