bluuebunny/crossref_metadata_2025 huggingface dataset:
Electronic structure and optical properties of Al-doped SnO2
Authors: Yu Feng  , Wang Pei-Ji  , Zhang Chang-Wen  ,   School of Science, University of Jinan, Jinan 250022, China
Published: December 2020

Based on the full-potential linearized augmented plane-wave method (FP-LAPW), we investigated the electronic structures and the optical properties, including dielectric function, absorption spectra, refraction and extinction of Sn1-xAlxO2 (x=0, 0.0625, 0.125, 0.1875, 0.25) via substituting for Sn with Al in SnO2 supercell. Calculated results show that the introduced Al could induce the band gap widening, and this can be attributed to the increased folded states, which lead to the contraction of the valence band and less Sn 5s states at the bottom of the conduction band. With the increasing of Al concentration, the band gap becomes wider, and the intensity of the first main peaks decreases. All of the optical spectra contain the imaginary part of dielectric function, the absorption spectrum, the refraction, and the extinction show blue shift corresponding to the increasing of the band gaps. Finally, it is expected that our results may inspire the future experimental research.
Momentum transfer cross sections of low-energy electron scattering from H2 molecule with the polarization potential using the distributed spherical Gaussian model
Authors: Wang Xiao-Lian  , Feng Hao  , Sun Wei-Guo  , Fan Qun-Chao  , Wang Bin  , Zeng Yang-Yang  ,   (1)College of Materials Science and Engineering, Sichuan University, Chengdu 610065, China; (2)Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, China; (3)Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, China;College of Materials Science and Engineering, Sichuan University, Chengdu 610065, China; (4)Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, China;Institute of Atomic and Molecular Physics, Sichuan Uni
Published: December 2020

Based on the distributed spherical Gaussian (DSG) polarization potential model, the momentum transfer cross sections (MTCSs) of low-energy electron scattering from H2 molecule are studied with the body frame vibrational close coupling (BFVCC) method and vibrational scattering potentials. The vibrational scattering potentials include the static, exchange, and correlation-polarization contributions calculated based on ab initio method. By including the contributions of 18 Morse vibrational wave functions, 5 partial waves, and 16 molecular symmetries, We obtained well converging MTCSs of ν=0→ν'=0, 1, 2, 3 transition excitations. The comparisons show that DSG polarization potential is a good approximation in the study of low energy electron scattering.
A two-dimensional broad pass-band left-handed metamaterial based on single-sided metallic structure
Authors: Chen Chun-Hui  , Qu Shao-Bo  , Xu Zhuo  , Wang Jia-Fu  , Ma Hua  , Zhou Hang  ,   (1)Key Laboratory of Electronic Materials Research Laboratory, Ministry of Education, Xi’an Jiaotong University, Xi’an 710049, China; (2)Science College, Air Force Engineering University, Xi’an 710051, China; (3)Science College, Air Force Engineering University, Xi’an 710051, China;Key Laboratory of Electronic Materials Research Laboratory, Ministry of Education, Xi’an Jiaotong University, Xi’an 710049, China
Published: December 2020

Through connecting magnetic resonators and coplanar short metallic wires together, a two dimensional left-handed metamaterial based on single sided metallic structure was proposed. Theoretical analysis and simulated results indicated that this construction exhibited negative effective permittivity and permeability simultaneously in a certain frequency range. Its relative negative refraction pass-band reached 36%. Meanwhile, this construction guaranteed relatively stable tolerance of errors. The resonant frequency and the width of the pass band are insensitive to the change in the width of the short metallic wires, which facilitates its fabrication and is of meaning for designing left-handed metamaterial in infrared or terahertz range.
Quantitative relation between "defects" distribution on optics and near-field quality in high power solid-state laser system
Authors: Zhou Li-Dan  , Su Jing-Qin  , Li Ping  , Wang Wen-Yi  , Liu Lan-Qin  , Zhang Ying  , Zhang Xiao-Min  ,   Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900, China
Published: December 2020

Based on beam propagation theory, the quantitative relation between PSD (power spectral density) of "defects" distribution on optics and that of near field intensity was studied. Its validity was discussed on linear medium, nonlinear medium and spatial filter. The results show that PSD of "defects" distribution on optics and PSD of near field intensity are connected by a system propagation factor when the modulation is weak, which is determined by system architecture and operation state. These results provide a theoretical basis for specifications of "defects" distribution on optics, and also a guidance to enhancing the power of high power solid-state laser system.
Analysis of the effect of phase-mismatch and material absorption on the terahertz-wave generation from GaSe
Authors: Lu Jin-Xing  , Huang Zhi-Ming  , Huang Jing-Guo  , Wang Bing-Bing  , Shen Xue-Min  ,   National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083, China
Published: December 2020

We analyzed the effect of phase-mismatch and material absorption on the terahertz-wave difference-frequency generation from GaSe theoretically. We calculated the best length of crystal and the corresponding terahertz power under four different conditions and the effect of angle-mismatch on phase-mismatch. The result provided a theoretical basis and reference to nonlinear optical difference-frequency experiments.
Metalloporphyrin bonded SiO2 organic-inorganic materials and their strong nonlinear refractive index
Authors: Zhang Xiao-He  , Wang Dong-Jie  , Xia Hai-Ping  ,   (1)Faculty of Materials Science and Chemica Engineering, Ningbo University, Ningbo 315211, China; (2)Key Laboratory of Photo-Electronic Functional Materials, Ningbo University, Ningbo 315211, China
Published: December 2020

Copper metalloporphyrin was bonded to 3-aminopropltriethoxysilane (NH2(CH2)3Si(OC2H5)3, KH550) by the chemical reaction between the carboxyl group of Cu(Ⅱ) meso-Tertra(4-carboxyphenyl)porphine (Cu(Ⅱ)-TCPP) and amino-group of KH550. The copper metalloporphyrin was connected to gel network after the hydrolysis and condensation of the product. The reaction product of different concentrations was hybridized with 3-glycidoxypropltrimethoxysilane (CH2OCHCH2O(CH2)3Si(OCH3)3, KH560) with sol-gel processing to form sol-gel inorganic material, which has good physical-chemical and optical properties. The cross-linkage of Cu(Ⅱ)-TCPP and KH550 was estimated and confirmed with FT-IR spectroscopy. The state of metalloporphyrin molecules was investiaged by UV/VIS spectra. It was found that the Cu(Ⅱ)-TCPP exists mainly in the state of monomer. Nonlinear optical properties of samples was studied by Z-scan technique using Ti:Sapphire femto-second laser pluses. The nonlinear refractive index n2 reached -1.1161×10-16 m2/W.
On-line detecting and controlling conception for time-delay measurement in ultrafast laser pulse pump-probe
Authors: He Xue-Peng  , Liu Yuan-Xing  , Liu Shi-Bing  ,   Institute of Laser Engineering, Beijing University of Technology, Beijing 100124, China
Published: December 2020

A novel optical system for detecting and controlling the time-delay value of probe light in the femtosecond pulse pump-probe measurements is presented based on the simultaneous phase-shifting interferometry scheme. The intensity distributions of interference pattern are calculated based on the Jones theory to optimize the optical system, by which the analytical expressions for phase-shifting length between the neighboring interferograms and the relevant phase-delay value are derived. To meet the requirement of practical application, possible latent errors in the process of detecting time-delay are analyzed. In particular, a minimum time-resolution with attosecond level at 800 nm wavelength was achieved. The results show that this system satisfies the requirement of femtosecond pulse pump-probe high-precision measurement.
Stabilizing second harmonic generation output using cascaded crystals
Authors: Deng Qing-Hua  , Zhang Xiao-Min  , Ding Lei  , Tang Jun  , Xie Xu-Dong  , Lu Zhen-Hua  , Zhao Run-Chang  , Dong Yi-Fang  ,   Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900, China
Published: December 2020

Theoretical study and numerical simulation were carried out on the newly proposed way of cascaded second harmonic generation (SHG) to get stable SHG output. The results certify that by way of using cascaded SHG one can obtain stable SHG output. Our results also show that by tuning the angle between k and the optical axis and the distance between the two SHG crystals, the length of the second SHG crystal for most stable SHG can also be tuned. When the length for most stable SHG is tuned to the real length of the second SHG crystal, stable SHG output was be obtained. Both stable SHG output and high SHG conversion efficiency can be got using this new way, and this will help a lot to design the pumping system for the optical pulse chirped amplifying system.
Numerical study of Hermite-Gaussian beams in nonlocal thermal media
Authors: Li Shao-Hua  , Yang Zhen-Jun  , Lu Da-Quan  , Hu Wei  ,   Laboratory of Photonic Information Technology, South China Normal University, Guangzhou 510631, China
Published: December 2020

Based on the nonlocal nonlinear Schrdinger equation and Poisson equation of thermal diffusion, using the slip-step Fourier algorithm and multi-grid method, we numerically investigated the propagation properties of Hermite-Guassian beams in the nonlocal thermal media. The results show that low-order Hermite-Gaussian beams can propagate stably, in contrast with the unstable propagation of high-order Hermite-Gaussian beams. The worse the stability is, the higher the order is. The effect of the boundary of the sample with different cross sections on the propagation properties of Hermite-Guassian beam is also discussed in detail. We found that propagation properties in square geometry are in agreement with those in Snyder-Mitchell model. However, in rectangular sample, the evolution of intensity distribution of Hermite-Gaussian beams differs seriously from that in the square sample.
Back conversion in optical parametric process
Authors: Liu Jian-Hui  , Liu Qiang  , Gong Ma-Li  ,   State Key Laboratory of Tribology, Center for Photonics and Electronics, Department of Precision Instruments and Mechanology, Tsinghua University, Beijing 100084, China
Published: December 2020

Back conversion is the key factor that affects the conversion efficiency, the beam quality of the parametric waves, and the stability of the output in the optical parametric process. For the reason of the variation of the back conversion with the distribution in the cross-section and with time, the back conversion cannot be eliminated thoroughly. We analyzed the problem of the back conversion in the optical parametric process, and established the models of the parametric process for the continuous waves and the pulsed waves, which help us study the key factors affecting the back conversion. According to the conclusion of our analysis, the proper length of the nonlinear crystals, the optimal distribution of the energy of the pump beam, and the proper parameters of the resonant cavity ( for optical parametric oscillators ) could reduce the back conversion and help to increase the conversion efficiency. According to the theoretical results, we designed an X-cut KTA (Potassium Titanyl Arsenate) optical parametric oscillator, and obtained the signal light with the energy of 270 mJ and the idler light with the energy of 150 mJ, which decreased the back conversion, and the efficiency reached 43%.
Guidance characteristics correlated to the core refractive index in a hybrid photonic crystal fiber
Authors: Cheng Tong-Lei  , Chai Lu  , Li Yan-Feng  , Hu Ming-Lie  , Wang Qing-Yue  ,   Key Laboratory of Opto-Electronic Information Science and Technology of Ministry of Education, College of Precision Instruments and Opto-Electronics Engineering, Tianjin University, Tianjin 300072, China
Published: December 2020

The properties of light guiding mechanism and modes relating to the core refractive index in a hybrid photonic crystal fiber (PCF) are numerically investigated by the full-vectorial finite element method. The light guiding mechanism of core mode is the double-bandgap-guiding when the core refractive index is smaller than the effective index of the air-hole cladding in the hybrid-PCF. If the core refractive index is between the refractive indexes of the two kinds of hybrid-claddings, there is a co-operative action of the index-guiding and the bandgap-guiding on the guide mode in the core. Only the total internal reflection guiding occurs in the fiber when the core refractive index is greater than the effective index of the high-index rod cladding. Comparison of these guiding properties in the hybrid-PCF are also carried out. The results provide guidance for the design of hybrid photonic crystal fiber for special purposes.
Dissonant standing-wave tube and the extremely nonlinear pure standing wave field
Authors: Min Qi  , Liu Ke  ,   (1)Key Laboratory of Noise and Vibration Research, Institute of Acoustics, Chinese Academy of Sciences, Beijing 100190, China; (2)Key Laboratory of Noise and Vibration Research, Institute of Acoustics, Chinese Academy of Sciences, Beijing 100190, China; Honghe University, Mengzi 661100, China
Published: December 2020

A standing-wave tube consisting of two tubes with abrupt changing diameters is dissonant, that is, its higher resonance frequencies are not integral multiples of the fundamental one. Using the dissonant property of the said standing-wave tube, the harmonics can be well suppressed and extremely pure nonlinear standing wave can be obtained at the first resonance frequency. Based on the study of the dissonant property of this standing-wave tube and by the straight connection of a high-power loudspeaker, 184 dB extremely pure nonlinear standing-wave field was obtained at the first resonance frequency. Moreover, the nonlinear standing-wave fields were experimentally investigated separately for the second resonance frequency up to the fifth. Relatively regular nonlinear standing-wave field of 180 dB was obtained at the third resonance frequency, and that of 166 dB was obtained at the fourth resonance frequency. The harmonics saturation phenomena and zigzag waveforms were observed at the third and the fifth resonance frequency, respectively.
Volume effect in the cyclic segregation of quasi two-dimensional binary granular mixture
Authors: Sun Gang  , Wu Yu-Hang  , Zheng Ning  , Wen Ping-Ping  , Li Liang-Sheng  , Shi Qing-Fan  ,   (1)Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; (2)Department of Physics, Beijing Institute of Technology, Beijing 100081, China
Published: December 2020

A systematic study about the cyclic segregation observed experimentally in a vertically vibrated quasi two-dimensional binary granular mixture is reported. The frequency-amplitude phase diagram was obtained, in which the region of cyclic segregation was found. We also measured the period of the cyclic segregation and showed the relationship between the period and total volume of granular mixture. Finally, the competition mechanism of percolation and condensation from Hong’s theory is used to explain the cyclic segregation and volume effect qualitatively.
A calculating model of sliding friction coefficient based on non-continuous energy dissipation
Authors: Huang Ping  , Gong Zhong-Liang  ,   (1)College of Mechanical and Electrical Engineering, Central South University of Forestry and Technology, Changsha 410004, China; (2)School of Mechanical and Automotive Engineering, South China University of Technology, Guangzhou 510640, China
Published: December 2020

A sliding friction coefficient calculation model was established based on analysis of non-continuous diffusion of energy during the interfacial friction. The results indicated that the sliding friction coefficient is not related with the load and the actual contact area under elastic contact. However, when the actual contact area is close to the nominal contact area, the sliding friction coefficient will increase along with the reducing load. When sliding is slow, the friction coefficient rises slowly with the increase of the sliding velocity, and the influence is more remarkable when the sliding speed is higher. Furthermore, the larger the atomic lattice, the smaller the sliding friction coefficient is. The sliding friction coefficient increases with the rising of the atomic temperature. These results will be used to engineering application and theoretical research.
Fractal analysis of Casson fluid flow in porous media
Authors: Yuan Mei-Juan  , Zheng Wei  , Yu Bo-Ming  , Yuan Jie  ,   (1)Key Laboratory of Dynamic Geodesy, Institute of Geodesy and Geophysics, Chinese Academy of Sciences, Wuhan 430077, China; (2)Key Laboratory of Systems Science in Metallurgical Process of Hubei Province, Department of Applied Physics, School of Science, Wuhan University of Science and Technology, Wuhan 430081, China; (3)School of Physics, Huazhong University of Science and Technology, Wuhan 430074, China
Published: December 2020

Fractal models for flow rate, velocity, starting pressure gradient and effective permeability for Casson fluid in porous media are proposed based on the fractal properties of porous media and capillary model. The proposed models are expressed as functions of fractal dimension, porosity, maximum pore size and representative length of porous media. All parameters in the proposed expressions have clear physical meaning, and the proposed models relate the properties of Casson fluid to the structural parameters of porous media. The velocity, starting pressure gradient and effective permeability versus different parameters are discussed, and the analytical expressions reveal the physical principles for flow velocity, starting pressure gradient and effective permeability in porous media.
Direct measurement technique for shock wave velocity under super high pressure
Authors: Wang Feng  , Peng Xiao-Shi  , Liu Shen-Ye  , Li Yong-Sheng  , Jiang Xiao-Hua  , Ding Yong-Kun  ,   (1)Institute of Applied Physics and Computational Mathematics, Beijing 100088,China; (2)Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900, China
Published: December 2020

With the ionization mechanism for the transparent material under the super high pressure, the basic measurement method of shock wave has been analyzed. With the Drude-free electron model, the change in reflectivity of shock wave front under different pressures has been analyzed. The reflectivity of shock wave front for different probe lasers has been compared in theory. And it was found that the reflectivity of shock wave front for 660 nm of probe laser is higher than that for 532 nm. The effect of the detector was found to be caused by the X-ray ionization of the transparent material after analyzing the reflectivity data in space-time scale. From the experiment data, it is found that the beginning of "blank" effect coincides with the start point of laser pulse. The shock wave is later than the "blank" effect under the square laser pulse. In the experiment, the reflectivity of shock wave front is about 40% when the shock velocity is 35 km/s. The theoretical decreasing curve of shock velocity in the sapphire window is confirmed by the experiment data. The formula to calculate the shock wave velocity in the transparent material was deduced and verified.
Optical emission spectra of Si plasma induced by femtosecond laser pulse
Authors: Gao Xun  , Song Xiao-Wei  , Guo Kai-Min  , Tao Hai-Yan  , Lin Jing-Quan  ,   (1)School of Science, Changchun University of Science and Technology, Changchun 130022, China; (2)School of Science, Changchun University of Science and Technology, Changchun 130022, China;School of Physical Science and Technology, Baotou Teachers College, Baotou 014030, China
Published: December 2020

The time- and space-resolved optical emission spectra (OES) of Si plasma produced by femtosecond laser pulse with center wavelength of 800 nm and pulse width of 100 fs in air were investigated. The results show that the OES mainly consist of continuous spectrum at the early stage of plasma expansion (within the first 50 ns), then the continuous spectrum weakens gradually while the line spectrum becomes dominating. The existence time of ion spectra is shorter than that of atomic spectra in the process of plume expansion. The wavelength red-shift, which has a second order exponential decay with delay time, has been found by the time-resolved emission spectroscopy. Finally, the spatiotemporal evolution of OES intensity are presented.
Numerical simulation of reaction-diffusion process of air plasma with a plasma source in open atmospheric environment
Authors: Yin Zeng-Qian  , Zhao Pan-Pan  , Dong Li-Fang  , Fang Tong-Zhen  ,   (1)College of Physics Science and Technology, Hebei University, Baoding 071002, China; (2)Department of Mathematics and Physics, North China University of Electric Power, Baoding 071003, China; (3)Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
Published: December 2020

A one-dimensional model is used to investigate the reaction-diffusion process of air plasma with a plasma source by numerical simulation in low pressure open atmospheric environment. The spatial evolutions of main charged species’ densities in the chemical reaction, drift and diffusion processes are obtained for a given plasma flow. The results of numerical simulation are combined with an approximate analytical formula to estimate the necessary plasma flow for electron density when a stable state is formed, with which the necessary power of the plasma source also can be estimated.
Characterization on the temperature of radio frequency argon capacitive discharge mode transition at atmospheric pressure
Authors: Guo Qing-Chao  , Zhang Jia-Liang  , Liu Li-Ying  , Wang De-Zhen  ,   School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024, China
Published: December 2020

The mode transition and coexistence were investigated in atmospheric pressure argon radio frequency capacitive discharge. By use of a program compiled by the authors for the nitrogen's second positive band simulation, comparison between the experimental and simulated spectra of band (0, 1) and (1, 2) was used to determine the rotational and vibrational temperatures of N2. The trends of vibrational and rotational temperatures with discharge power were studied to observe the temperature jump corresponding to the discharge mode transition. Utilizing a well-known software named Lifbase, the simulated spectra of OH (A—X)(0, 0) was calculated to obtain the rotational temperature of OH by comparing with the experimental OH (A—X)(0, 0) band. The calculated rotational temperature of OH is well consistent with the result of nitrogen's second positive band, which shows that the neutral species are at thermal equilibrium in the space of discharge. According to the current-voltage characteristic, the temperature jump corresponding to the discharge mode transition was confirmed in accordance with the photograph of discharge.
X-ray radiation power optimization in 1MA to 4MA wire-array implosions
Authors: Wang Zhen  , Li Zheng-Hong  , Xu Rong-Kun  , Yang Jian-Lun  , Ding Ning  , Xu Ze-Ping  , Guo Cun  , Ning Cheng  , Ning Jia-Min  , Jiang Shi-Lun  , Zhang Fa-Qiang  , Xia Guang-Xin  , Li Lin-Bo  , Ye Fan  , Qin Yi  , Xue Fei-Biao  , Chen Jin-Chuan  ,   (1)Institute of Applied Physics and Computational Mathematics, Beijing 100088, China; (2)Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900, China
Published: December 2020

Tungsten wire array implosions driven by 1 MA to 4 MA current were experimentally investigated. X-ray radiation power was improved through load parameters optimization,electrode structure improvement and well control of initial array conditions. The maximum powers of 5.3±1.0 TW and 5.6±1.1 TW, the highest at the 3 MA to 4 MA current level up to now, were measured in the single array and the double array implosions, respectively.
Effect of temperature gradient on the non-equilibrium rate of flux emitted by plane gold wall
Authors: Meng Guang-Wei  , Li Jing-Hong  , Pei Wen-Bing  , Li Shuang-Gui  , Zhang Wei-Yan  ,   (1)Institute of Applied Physics and Computational Mathematics, Beijing 100088, China; (2)National High Technology Inertial Confinement Fusion Committee, Beijing 100088, China
Published: December 2020

In the theoretical and experimental research of radiation transport in inertial confinement fusion (ICF), the radiation spectrum in the foam cylinder can be changed by the surrounding high-Z wall. In this paper, we simulated and studied the property of flux emitted by the high-Z wall using 1-D plane model. Our work shows that the gradient of electron temperature is the reason why spectrum of flux emitted by the high-Z wall deviates from equillibrium. In order to quantitatively study the property of flux emitted by the high-Z wall, we define the non-equilibrium rate and deduced its estimating formula in the temperature scale of ICF experiment.
Radio frequency identification anti-collision test based on Markov chain model
Authors: Hou Zhou-Guo  , He Yi-Gang  , Li Bing  ,   (1)College of Electrical and Information Engineering, Hunan University, Changsha 410082, China; (2)College of Electrical and Information Engineering, Hunan University, Changsha 410082, China;Department of Communication and Control Engineering, Hunan Institute of Humanities Science and Technology, Loudi 417000, China
Published: December 2020

The anti-collision theory of adaptive Q algorithm and radio frequency identification(RFID) communication timing sequence were analyzed. Then a Markov chain model for simulating multi-tag identification process was established based on the following three definitions. The definitions are identifying efficiency, identifying speed and data state(Q, n), where n is the total remanent tag number, and Q is the slot count. The identifying efficiency and speed were obtained from the model using Monte Carlo statistical method. A software-defined radio program was built to simulate the collision of RFID which could quantify the identifying efficiency and speed effectively. The consistency of model simulation result and test data proves the validity of the model and test method.
Numerical study on Hall thruster magnetic configuration and its optimization
Authors: Deng Li-Yun  , Lan Hong-Mei  , Liu Yue  ,   School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024, China
Published: December 2020

Based on Maxwell's equations, under axis-symmetric assumption, a mathematical model of the magnetic field of a Hall thruster is established. A finite difference method is used for discretizing the model. An iterative method for numerically solving the model is given. The numerical results are obtained. From analysis of the results, the effect of the current in the magnetic field coils on the magnetic configuration of a Hall thruster is investigated. Through adjusting the current, the ideal magnetic configurations are found. It was shown that, for ideal magnetic configuration, the magnetic mirror ratio in the inner channel is between 3 and 3.5, and the magnetic mirror ratio in the outer channel is between 0.4 and 0.9. With the increasing of the current in the magnetic field coils, the magnetic field at the exit of the channel increases, but the magnetic mirror ratio cannot be increased. The magnetic field in the inner channel hardly changes with change of the currents in the magnetic field coils.
Numerical simulation of outgassing in the breakdown on dielectric surface irradiated by high power microwave
Authors: Cai Li-Bing  , Wang Jian-Guo  ,   (1)Northwest Institute of Nuclear Technology, Xian 710024, China; (2)Northwest Institute of Nuclear Technology, Xian 710024, China;School of Electronic and Information Engineering, Xi'an Jiaotong University, Xi'an 710049, China
Published: December 2020

A simple outgassing model for dielectric surface breakdown due to the high power microwave (HPM) irradiation was establised. By using the PIC (particle-in-cell)-MCC(Monto Carlo collisions) method, the numerical simulation program of the dielectrics surface breakdown was developed, and the simulation of breakdown for different outgassing speeds was performed. The temporal evolution of the electron number and delay time of the process of breakdown in the case of different outgassing speeds were obtained. The numerical results show that when the speed of outgassing is small, the breakdown does not occur for an HPM pulse of a given duration, because the formation of the gas layer on the dielectric surface is slow. When the speed of outgassing is greater than a certain value, the breakdown occurs and the breakdown delay time shortens with the gas desorption rate increasing in a certain range. Finally, the numerical simulation results were compared with the experimental results of the direct current dielectric surface breakdown, and the trends of their development agree very well.
Crystallization and microstructure change of semiconductor active thin layer in polymer organic field-effect transistors
Authors: Jia Quan-Jie  , Chen Yu  , Tian Xue-Yan  , Yao Jiang-Feng  , Zhao Su-Ling  , Fan Xing  , Gong Wei  , Xu Zheng  , Zhang Fu-Jun  ,   (1)Beijing Asahi Glass Electronics Co. , Ltd. , Beijing 100016, China; (2)Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China; (3)Key Laboratory of Luminescence and Optical Information of Ministry of Education, Institute of Optoelectronics Technology, Beijing Jiaotong University, Beijing 100044, China
Published: December 2020

The crystallization and microstructure change of self-organization and the related conduction mechanisms of polymer semiconductor active thin layer in polymer organic field-effect transistors (OFET) are investigated by synchrotron radiation grazing incident X-ray diffraction (GIXRD) for understanding the relationships between polymer self-organization and charge carry. The change of the crystalline microstructure of RR-P3HT clarifies the effect of SAMs for improving the interface between the insulator layer and the organic semiconductor layer. The self-organiztion of RR-P3HT modified by SAMs improves the crystalliztion to pack form the thiophene rings along the perpendicular direction of substrate and results in that the π-π interchains are stacked to parallel the substrate. The two-dimensional charge transport is improved. Furthermore, we find that two-dimensional, conjugated, and self-organized crystalline lamellae are easier to gain with slow grown film than with fast grown film.
Preparation and electrical properties of double-doped perovskitestructured conducting ceramics Sm0.9Sr0.1Al1-xCoxO3-δ
Authors: Xiang Jun  , Guo Yin-Tao  , Chu Yan-Qiu  , Zhou Guang-Zhen  ,   School of Mathematics and Physics, Jiangsu University of Science and Technology, Zhenjiang 212003, China
Published: December 2020

A series of new mixed-conducting ceramics Sm0.9Sr0.1Al1-xCoxO3-δ(SSAC, x=0.2, 0.4, 0.5, 0.6) with perovskite structure were prepared by sintering the precursor powders derived from organic gel process. The effects of sintering temperature and Co doping concentration on the crystal structure, phase composition and electrical properties were also discussed in detail. The X-ray diffraction results show that the over-high sintering temperature or Co doping content will lead to the formation of impure phase with a chemical formula of Sm(Sr)CoO3 in sinters, and the solid solubility limit of Co in this system lies in the range of 50 mol%—60 mol%. The partial substitution of Co for Al in Sm0.9Sr0.1Al1-xCoxO3-δ results in an increase in lattice volume. The measurement results of electrical properties reveal that the conductivities of SSAC ceramics are dominated by p-type conduction, and the conduction behavior conforms to the small polaron hopping transport mechanism. With the increasing sintering temperature, the conductivities of as-prepared samples gradually increase. For the SSAC ceramics with Co content lower than the solid solubility limit, it is observed that their conductivities increase with the increase of Co content while the corresponding apparent activation energies decrease. The prepared single-phase Sm0.9Sr0.1Al0.5Co0.5O3-δ ceramic body by sintering at 1200℃ for 10h has a conductivity of 63.4 S/cm and an apparent activation energy of 0.14eV. These novel SSAC mixed-conducting ceramics with good electrical properties can potentially be used in the field of high temperature electrochemistry.
Theoretical investigation of anti-reflection properties of Ag-nanoparticles
Authors: Han Tao  , Meng Fan-Ying  , Zhang Song  , Wang Jian-Qiang  , Cheng Xue-Mei  ,   Solar Energy Institute, Department of Physics, Shanghai Jiao Tong University, Shanghai 200240, China
Published: December 2020

In order to trap more sunlight onto the crystalline silicon solar cell and improve the photo-electric conversion efficiency, it is very important to study the optical scattering properties of silver nanoparticles on silicon wafer. Based on localized surface plasmon effect and MIE scattering theory, using numerical calculation by Matlab, the scattering properties of solar spetra for different radius and density of silver nanoparticle are investigated in theory. The dependence of the optimal optical transmittance on the radius and density of Ag nanoparticle is obtained. Furthermore, it is found that the dipole peaks is redshifted and high mode peaks gradually emerges. Firstly this paper gives the variation of the best Ag nanoparticle density with the radius quantitively, the theoretical method calculating the transmittance of the nanoparticle antireflection film is also established. As a result, the simple functional expression of transmittance is deduced in this work, which provides a theoretical guidance for experimental research.
Electrical transport and photo-induced properties in Fe3O4 film
Authors: Luo Bing-Cheng  , Chen Chang-Le  , Xie Lian  ,   Key Laboratory of Condensed Matter Structural and Properties of Shaanxi Province, Northwestern Polytechnical University, Xi' an 710029, China
Published: December 2020

Highly oriented Fe3O4 film was fabricated on Si (111) substrate by pulsed laser deposition. The resistivity-temperature curve shows that the Verwey transition point is about 122 K, and the electrical transport mechanism agrees with Mott varial-range hopping model and the small polaron model for temperatures below TV and above TV, repectively. The laser irradiation results in the decrease of the resistivity of the film in the whole temperature range were measured, which is attributed to the intersite transitions of Fe 3d t2g electrons.
Origin of ferromagnetic properties in Ni doped ZnO by the first principles study
Authors: Shi Li-Bin  , Xiao Zhen-Lin  ,   (1)Department of Physics, Bohai University, Jinzhou 121013, China; (2)School of Chemistry and Chemical Engineering, Bohai University, Jinzhou 121013, China
Published: December 2020

Theoretical calculation based on density functional theory (DFT) and local density approximation (LDA) has been carried out to study the magnetic properties of Ni doped ZnO. The results show that ferromagnetism (FM) coupling between Ni atoms is more stable for 8 geometrically distinct configurations. The results from density of states show that O 2p hybridizes with Ni 3d, which results in electronic states spin polarization at the Fermi energy. Moreover, the effect of oxygen vacancy on FM properties of Ni doped ZnO has also been investigated. It was found that FM coupling is enhanced in the presence of oxygen vacancy, which is strong enough to lead to electron-mediated ferromagnetism at room temperature. In addition, the origin of the FM state in Ni doped ZnO has also been discussed by analyzing the coupling of Ni 3d levels. We also analyzed the strain effect on FM properties of Ni doped ZnO.
Deduction and verification of electromagnetic parameter of arbitrary polyhedron cloaks
Authors: Liu Jia  , Xu Zhuo  , Qu Shao-Bo  , Gu Chao  , Pei Zhi-Bin  , Gu Wei  ,   Department of Computer Science and Technology,The Engineering and Technical College, Chengdu University of Technology,Leshan 614300, China;,   Key Laboratory of Electronic Materials Research of Ministry of Education, Xi’an Jiaotong University, Xi’an 710049, China;,   Science College, Air Force Engineering University, Xi’an 710051, China;,   Science College, Air Force Engineering University, Xi’an 710051, China;Key Laboratory of Electronic Materials Research of Ministry of Education, Xi’a
Published: December 2020

On the basic of the coordinate transformation theory, we deduce the condition for irregular polyhedron cloaks and obtain tensor expressions of electromagnetic parameters. Using tensor expressions of electromagnetic parameters, we verify the effect of 4-sided polyhedron cloak and 14-sided polyhedron cloak through full-wave simulations. The results confirm the validity of tensor expressions of electromagnetic parameters we derived. The present work may serve as a basis for the design of three-dimensional baroque cloak.
Upconversion luminescence properties of Y2SiO5: Er3+ ,Yb3+ ,Tm3+ synthesized by co-precipitation method
Authors: Guo Lin-Na  , Wang Yu-Hua  ,   School of Physical Science and Technology, Lanzhou University, Lanzhou 730000, China
Published: December 2020

A series of up-conversion luminescence materials of Y1.98-2xYb2xEr0.02SiO5(0.00≤x≤0.15) and Y1.736Yb0.24Er0.02Tm0.004SiO5 were synthesized by co-precipitation method.The absorption spectra from 400 to 1600 nm of Y1.98-2xYb2x Er0.02SiO5 (x=0.00,0.08) were compared, and the up-conversion emission spectra of all samples were investigated when excited by 976 nm opo laser. The decay curves of Er3+4S3/2(4F9/2)→ 4I15/2,Tm3+1G4→3H6,as well as the relationship between the blue up-conversion emission intensity and pumping power were measured,consequently, the possible up-conversion luminescence mechanisms of Er3+,Tm3+ in Y2SiO5 were discussed. The results show that X2-type monoclinic Ln3+(Ln3+=Er3+,Yb3+,Tm3+) co-doped Y2SiO5 phosphors have been synthesised under relatively low temperature of 1250 ℃, and the absorption intensity and bandwidth are remarkably increased by Yb3+ sensitizing around 976 nm. Up-conversion emission spectra has been analyzed and the results suggest that both the green and red lights increase first and then decrease with the increase of the Yb3+ doping concentration. However,the concentration quenching of the red light emission is higher, due to the forward (ETU3) and back (ETU4) energy transfer between Yb3+ and Er3+ ions; the blue emission occurs mainly through phonon-assisted energy transfer between Yb3+ and Tm3+ ions, which is a three photon absorption process.
Silicon surface microstructures created by 1064 nm Nd∶YAG nanosecond laser
Authors: Yang Hong-Dao  , Li Xiao-Hong  , Li Guo-Qiang  , Yuan Chun-Hua  , Tang Duo-Chang  , Xu Qin  , Qiu Rong  , Wang Jun-Bo  ,   Laser and photoelectron Laboratory, School of Science, Laboratory of Matter Characteristic Research at Extreme Conditions, Southwest University of Science and Technology, Mianyang 621010, China
Published: December 2020

We investigated the evolution of surface microstructures created on single crystal silicon wafers by the cumulative Nd ∶YAG nanosecond laser pulses (wavelength 1064 nm ) in different atmospheres (N2, air and vacuum). Micropore structure and the fracture lines are formed after irradiation of a few laser pulses,compared with ripple structures created by laser pulses of wavelengths of 532 and 355 nm. The fracture line structure is different for (111) and (100) silicon. The fracture lines have 60°and 120° intersections for (111) silicon. For (100)-oriented silicon wafers, two sets of fracture lines intersect at 90° to form a grid that divides the surface into rectangular blocks with side length of from 15 to 20 μm. We think that phase explosions are responsible for the growth of micropore structure. The fracture lines are mainly due to thermal stress. Finally, We studied the formation of microstructures under different atmospheres, and the results show that it is closely related to the etching and growth rate.
Epitaxial growth of Ge0.975Sn0.025alloy films on Si(001) substrates by molecular beam epitaxy
Authors: Su Shao-Jian  , Wang Wei  , Zhang Guang-Ze  , Hu Wei-Xuan  , Bai An-Qi  , Xue Chun-Lai  , Zuo Yu-Hua  , Cheng Bu-Wen  , Wang Qi-Ming  ,   State Key Laboratory on Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
Published: December 2020

Ge0.975Sn0.025 alloy films have been grown on Si(001) substrates by molecular beam epitaxy with high-quality Ge films as buffer layers.The alloys have high crystalline quality without Sn surface segregation, determined by double crystal X-ray diffraction and Rutherford backscattering spectra measurement. In addition, the Ge0.975Sn0.025 alloy has rather good thermal stability at 500 ℃, which makes it possible to be used in Si-based optoelectronic devices.
Direct measurement of group delay of optical elements
Authors: Deng Yu-Qiang  , Sun Qing  , Yu Jing  ,   Optics Division, National Institute of Metrology, Beijing 100013, China
Published: December 2020

A technique for direct measurement of group delay of optical elements is introduced. With the joint time-frequency analysis of white-light spectral interferogram, group delay can be directly extracted from the ridge of wavelet-transform. The technique is accurate and simple. The measurement results of group delay and group delay dispersion of a piece of fused silica was demonstrated. The results agree well with those from theoretical calculation, and the noise is greatly reduced. This technique is suitable for various application of white-light interferometer.
Effect of Al(OH)3 sol concentration on characteristics of microarc oxidation coatings of titanium alloy
Authors: Yu Song-Nan  , Wu Han-Hua  , Chen Gen-Yu  , Yuan Xin  , Li Yue  ,   College of Physics, Jilin University, Changchun 130021, China
Published: December 2020

The effect of Al(OH)3 sol on the growth characteristics, microstructure, phase structure and electrochromic properties of the coating fabricated on titanium alloy substrates were investigated by means of changing the Al(OH)3 sol concentration. The results show that the rate of growth of coating thickness gradually increased from slow to fast with the increasing concentration of Al(OH)3 sol and the roughness and size of micropore on the coating surface gradually increased, while its pore density was reduced. The coating was composed of anatase TiO2 when the volume fraction C≤10%. The rutile TiO2 began to emerge at C>10%, and its relative content gradually increased with the increase of the Al(OH)3 sol concentration. When C=40%, the obtained coating was composed of rutile TiO2. The cyclic voltammetry tests in pH 2.0 HCl solution showed that the color of the sample fabricated at C≤20% did not change significantly, with the increase of the Al(OH)3 sol concentration, the color change of the sample became clear. When C=40%, the obtained sample showed good stability and reversibility between blue coloration and bleaching cycles in pH 2.0 HCl solution.
A first principles study of the lattice dynamics property of LiFePO4
Authors: Xin Xiao-Gui  , Chen Xiang  , Zhou Jing-Jing  , Shi Si-Qi  ,   Center for Optoelectronics Materials and Devices, Department of Physics, Zhejiang Science Technology University, Hangzhou 310018, China
Published: December 2020

Lattice dynamical properties of LiFePO4 were studied using first principles density functional theory taking into account the on-site Coulomb interaction within the GGA+U scheme. The Born effective charge tensors, phonon frequencies at the Brillouin zone center and phonon dispersion curves were calculated and analyzed. The Born effective charge tensors exhibit anisotropy, which gives an indirect evidence for the one-dimensional Li migration tunnel along the [010]direction in LiFePO4, which has been proposed by other theoretical calculations and experimental observations. The calculated phonon frequencies at the Г point of the Brillouin zone agree well with the available experimental results.
Base resistance in Si unijunction transistor irradiated by 60Co γ-radiation
Authors: Zhao Hong-Fei  , Du Lei  , He Liang  , Bao Jun-Lin  ,   (1)School of Microelectronic, Xidian University, Xi'an 710071, China; (2)School of Technology Physics, Xidian University, Xi'an 710071, China
Published: December 2020

The change of base resistance in Si-UJT under irradiation of 60Co γ-ray is provided. Through multipoint measurement and real-time monitoring, it was shown that the base resistance decreased immediately and then increased slowly. Compared with domestic and foreign related research results, this proves that the displacement effect is the main effect of base resistance in Si-UJT irradiated by 60Co γ-ray, but it lags behind the ionization effect from microanalysis of the interaction between γ-ray and Si material. This is very important for the radiation hardened research.
Total dose characteristics of single poly EEPROM and SONOS EEPROM on SOI
Authors: Xiao Zhi-Qiang  , Li Lei-Lei  , Zhang Bo  , Xu Jing  , Chen Zheng-Cai  ,   State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054, China;,   State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054, China;The 58th Research Institute of China Electronics Technology Group Corporation, Wuxi 214035, China;,   The 58th Research Institute of China Electronics Technology Group Corporation, Wuxi 214035, China;,   The 58th Research Institute of China Electronics Technology Group Corporation, Wuxi 214035, China;School of Microelectronics, Xidian University, Xi’an 710071, China
Published: December 2020

Devices of single poly electrically ersable programmable read only memory (EEPROM) and silicon-oxide-nitride-oxide-silicon (SONOS) EEPROM on silicon on insulator (SOI) are fabricated on self-built 0.8 μm SOI process. And through a set of experiments on EEPROMs of these configurations and comparisons, SOI SONOS EEPROM is successfully developed with good and stable total dose radiation hardened characteristics. These provide stronger proofs to choose EEPROM in radiation hardened circuits.
Effect of spectrum-control in dual-wavelength light-emitting diode by doped GaN interval layer
Authors: Zhang Yun-Yan  , Fan Guang-Han  , Zhang Yong  , Zheng Shu-Wen  ,   Institute of Opto-Electronic Materials and Technology, South China Normal University, Guangzhou 510631, China
Published: December 2020

A two-dimensional simulation of electrical and optical characteristics of dual-wavelength LED (light-emitting diode) with doped GaN interval layer is conducted with software.It shows that by the use of doped GaN interval layer, we can solve the luminescence intensity disparity of the two kinds of quantum wells in dual-wavelength LED. And through control of the thickness of the interval layer, we can adjust the relative luminescence intensity of the two kinds of quantum wells. Therefore, the effect of spectrum-control in dual-wavelength LED is due to the blocking effect of holes or electrons by doped GaN interval layer.