bluuebunny/crossref_metadata_2025 huggingface dataset:
Visible light metamaterials based on the double-fishnet structure
Authors: Zhao Yan  , Xiang Jian-Kai  , Li Sa  , Zhao Xiao-Peng  ,   Smart Materials Laboratory, Department of Applied Physics, Northwestern Polytechnical University, Xi' an 710129, China
Published: December 2020

A novel method was proposed to fabricate double-fishnet structure metamaterials working at visible frequencies. Via template-assisted electrochemical deposition, silver nanonets with different lattices were fabricated, which were used to achieve final double-fishnet structures. It was revealed that the passband of the silver nanonet structure was shift to shorter wavelength when changing the lattice of structure smaller, according to the transmission spectra. Silver nanonet with lattice of 420 nm was used to achieve double-fishnet structure, which has novel effects at 610 nm wavelength, such as enhanced transmission and planar focusing. Furthermore, it is possible to fabricate double-fishnet structure metamaterials working at shorter wavelengths even for blue light when using template with smaller lattice.
The research of the air-sensitive sensor based on thephotonic crystal beam splitter
Authors: Kong Yan-Mei  , Gao Chao-Qun  , Jing Yu-Peng  , Chen Da-Peng  ,   Integrated Circuit Advanced Process Center, Key Lab of Microelectronics Device and Integration Technology,Institute of Microelectronics, Chinese Academy of Sciences, Beijing 100029, China
Published: December 2020

The spectroscopy is the ultimate way for chemical analysis. This paper mainly describes the idea of an air-sensitive sensor based on MEMS technology, and more over, a photonic crystal (PC) beam splitter was designed, which can achieve high resolution beam steering, and this improves the resolution of the sensor. The paper offers a new idea and lays the foundation for the novel beam splitter that applied to many optical systems.
Research of implosion dynamics for wire array Z pinch
Authors: Sheng Liang  , Qiu Meng-Tong  , Hei Dong-Wei  , Qiu Ai-Ci  , Cong Pei-Tian  , Wang Liang-Ping  , Wei Fu-Li  ,   Northwest Institute of Nuclear Technology, Xi’an 710024, China
Published: December 2020

The implosion dynamics of wire array Z pinch can be divided into four stages: (1) wire ablation; (2) formation of plasma shell; (3) implosion; (4) stagnation. Based on the optical-framing camera and the soft X-ray framing camera, lots of experiments on the early stage of wire array Z pinch and imploding dynamics have been carried out. Images of wire array Z pinch from wire ablation to plasma column breakdown were obtained. The main results were as follows: (1) There is a long ablation stage, and the wire ablation is not uniform along the axis. The imploding experimental trajectory is consistent with the phenomenological model. (2) The cathode emission is obviously observed in both optical images and X ray images. In the late stage of implosion, there is obvious trailing radiation distribution around the cathode. (3) The precursor plasma column is formed after the collision of the ablating plasma at the axis, which expands at first, then becomes compressed. (4) The temperature and ionization stage of corona plasma were estimated according to its azimuthally expanding velocity.
Radition effect on Ti/4H-SiC SBD of gamma-ray,electrons and neutrons
Authors: Zhang Lin  , Xiao Jian  , Qiu Yang-Zhang  , Cheng Hong-Liang  ,   School of Electronic and Control Engineering, Chang'an University, Road Traffic Detection and EquipmentEngineering Research Center, Chang'an University, Xi'an 710064, China
Published: December 2020

The Ti/4H-SiC Schottky barrier diodes(SBDs) were irradiated at room temperature with 60Co gamma-ray source, 1MeV electrons and neutrons, and 0V and -30 V bias voltage were applied to the diodes during gamma-ray and electron radiation. The meaurement results show that -30 V radiation bias voltage has no influence on the radiation effect of the diodes. After 1 Mrad(Si) gamma-ray and 1×1013 n/cm2neutron radiation respectively, the Schottky barrier height of the diodes basically remain the same values. After an electron dose of 3.43×1014 e/cm2, Schottky barrier height of the diodes slightly decreased, which was caused by ionizing damage of high energy electron, and recovered completely after annealing at room temperture. After gamma-ray and electron radiation, the reverse current of Ti/4H-SiC SBD had no obviously degration. The on-state resistance of the diodes increased after electron and neutron radiaiton.
First principles study of interactions between Au and N atoms on SrTiO3(001) surface
Authors: Fang Li-Min  ,   Department of Physics, Guangdong University of Education, Guangzhou 510303, China
Published: December 2020

First principles PWPP calculations based on the density functional theory were carried out to study the microscopic mechanism of the interaction between Au and N atoms on SrTiO3(001) surface. From analysis of the related energies and density of states, it was confirmed that there is clearly a synergy effect between the substitution of N for the surface O atoms and the adsorption of Au atoms on the SrTiO3(001) surface. In other words, the substitution of N atoms for O atoms stabilizes the Au atoms adsorbed on the surface, and the presence of the adsorbed Au atoms can also favor the process of N substitution on the surface.
H∞ synchronization of general chaotic systems with random perturbations
Authors: Tu Li-Lan  , Ke Chao  , Ding Yong-Mei  ,   Hubei Province Key Laboratory of Systems Science in Metallurgical Process, Wuhan University of Science and Technology, Wuhan 430081, China
Published: December 2020

In this paper, the H∞ synchronization of general chaotic systems with random perturbations is investigated, in which perturbation is a random process of Brownian motion. Based on stochastic Lyapunov stability theory, linear matrix inequalities, and It formula and H∞ control method combined with feedback control laws, some new asymptotic synchronization schemes are established which guarantee robust stochastical mean square asymptotical synchronization for drive system and noise-perturbed response system, as well as achieving a prescribed stochastic robust H∞ performance level. These schemes are in a simple form and easy to work with Matlab. Finally, simulations show that the proposed results are correct and effective.
Propagation properties of a surface plasmonicwaveguide with a bowtie air cores
Authors: Jia Zhi-Xin  , Duan Xin  , Lü Ting-Ting  , Guo Ya-Nan  , Xue Wen-Rui  ,   College of Physics and Electronic Engineering, Shanxi University, Taiyuan 030006, China
Published: December 2020

A kind of surface plasmonic waveguide with a bowtie shaped air core was designed. The dependence of distribution of longitudinal energy flux density, effective index and propagation length of the fundamental mode supported by this waveguide on geometrical parameters and working wavelength were analyzed using the finite-difference frequency-domain (FDFD) method. Results show that the longitudinal energy flux density distributes mainly in the center region which is formed by the top and the bottom ridge. The effective index and propagation length of the fundamental mode can be adjusted by the geometric parameters as well as the working wavelength. At a given working wavelength, the effective index decreases as the radius of ridge increases, meanwhile propagation length and mode area of the fundamental mode increase as radius of ridge increases. The geometric parameter of radius of circles at four corner can affect the propagation properties slightly. The radius of sectors on both sides can effect propagation properties obviously. With given geometric parameters, relative to the case of λ=705.0 nm, in the case of larger λ, the area of field distribution is larger, and the size of the contact area of field and metallic surface is also larger, then the interaction of field and silver is weaker, and the effective index becomes smaller, so the propagation length becomes larger. The possibility of applying this kind of surface plasmonic waveguide to the field of sensors was discussed.
Metal organic decomposition technique and optical propertiesof amorphous Ba0.7Sr0.3TiO3 thin films
Authors: Wang Shang-Bao  , Dong Ze-Hua  , Xu Zhi-Mou  , Peng Jing  ,   (1)College of Sciences, Wuhan University of Science and Technology, Wuhan 430081, China; (2)School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074, China; (3)Wuhan National Laboratory for Optoelectronics, Wuhan 430074, China; College of Optoelectronic Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
Published: December 2020

With the development of Si-based optical integrated circuit, much attention has been paid to the crystalline and amorphous (BaxSr1-x)TiO3(BST) films due to its good optical properties. In this study, the amorphous Ba0.7Sr0.3TiO3 (BST0.7) thin films were grown on the fused quartz and silicon substrates at low temperature by using a metal organic decomposition (MOD)-spin-coating procedure from barium 2-caprylate Ba(C8H15O2)2 and 3-methylbutyl acetate CH3COOC2H4CH(CH3)2-based special precursors. The optical constants of amorphous BST0.7 thin films including refractive index, extinction coefficient and optical band gap energies were presented. Photoluminescence spectra of BST0.7 films were also observed. The calculated extinction coefficient of 214-nm-thick amorphous BST0.7 thin films in visible and near-infrared region was of the order of 10-3, which is much lower than that of polycrystalline BST thin films. The optical band gap energy and refractive index n were estimated to be about 4.27 eV and n=1.94, respectively. Intensive photoluminescence at room temperature was achieved in the 520 to 610 nm wavelength range with a strong visible peak at 540—570 nm when excited by 450 nm laser light. No photoluminescence was observed in crystalline BST0.7 thin films.
Analysis of multi-switching period oscillation phenomenon in constant on-time controlled buck converter
Authors: Wang Jin-Ping  , Xu Jian-Ping  , Xu Yang-Jun  ,   School of Electrical Engineering, Southwest Jiaotong University, Chengdu 610031, China
Published: December 2020

In this paper, multi-switching period oscillation phenomenon in constant on-time (COT) controlled buck converter is studied, and the effect of output capacitor equivalent series resistance (ESR) on the control performance of COT controlled buck converter is revealed. The study results indicate that ESR is the critical factor causing multi-switching period oscillation phenomenon in the COT controlled buck converter, and critical value of ESR is obtained. When the value of ESR is less than the critical value, the multi-switching period oscillation phenomenon occurs, and it disappears when the value of ESR is higher than the critical value. Finally, the theoretical results are verified by simulation.
Protocol for deterministic entanglement concentration of three pairs of partially entangled particles
Authors: Zhang Wen-Zhao  , Li Wen-Dong  , Shi Peng  , Gu Yong-Jian  ,   Department of Physics, Ocean University of China, Qingdao 266100, China
Published: December 2020

According to the Nielsens theorem and the basic idea of entanglement concentration, we improve and extend the deterministic entanglement concentration protocol that extracts one pair of maximally entangled particles out of two pairs of non-maximally entangled particles, thus establishing a deterministic entanglement concentration protocol that extracts two pairs of maximally entangled particles out of three pairs of non-maximally entangled particles in the way of the classical communication and local operation and the specific positive operator-valued measure. This is helpful for establishing a deterministic entanglement concentration protocol that extracts k pairs of maximally entangled particles out of n pairs of non-maximally entangled particles.
Analysis of Hopf bifurcation in voltage-controlled boost converter under different switching frequencies
Authors: Wang Fa-Qiang  , Ma Xi-Kui  , Yan Ye  ,   State Key Laboratory of Electrical Insulation and Power Equipment, School of Electrical Engineering, Xian Jiaotong University, Xian 710049, China
Published: December 2020

Due to the absence of the switching frequency in the conventional average model of the voltage-controlled boost converter, this model cannot be used to analyze the influence of the switching frequency on the Hopf bifurcation in the voltage-controlled boost converter. In this paper, the influence of the switching frequency on the Hopf bifurcation in the voltage-controlled boost converter is analyzed by establishing the improved averaged model, which contains the switching frequency. The circuit is designed, and some typical experimental results are given. It is found that it is effective to use the improved average model to analyze the influence of the switching frequency on the Hopf bifurcation in the voltage-controlled boost converter and the Hopf bifurcation is easy to occur when the switching frequency of the voltage-controlled boost converter decreases.
808nm vertical-cavity surface-emitting laser with large aperture
Authors: Hao Yong-Qin  , Feng Yuan  , Wang Fei  , Yan Chang-Ling  , Zhao Ying-Jie  , Wang Xiao-Hua  , Wang Yu-Xia  , Jiang Hui-Lin  , Gao Xin  , Bo Bao-Xue  ,   State Key Laboratory of High-Power Semiconductor Lasers, Changchun University of Science and Technology, Changchun 130022, China
Published: December 2020

For the carriers-crowded effect in vertical-cavity surface-emitting laser (VCSEL), the injected current passes mainly through the edge of the circular active region, which results in nonuniformity of the output power density and annular facula with a poor central intensity, especially in large aperture VCSEL. How to restrain carriers-crowded effect becomes a technique problem to develop electrically pumped high power large aperture VCSEL. High power 808 nm VCSEL is demonstrated by introducing a novel structure. And an output power of 0.3 W is achieved at 1 A at room temperature under continuous wave operation.
A kinetics model for the chemical vapor deposition growth of SiGe/Si heterojunction materials
Authors: Dai Xian-Ying  , Jin Guo-Qiang  , Dong Jie-Qiong  , Wang Chuan-Bao  , Zhao Xian  , Chu Ya-Ping  , Xi Peng-Cheng  , Deng Wen-Hong  , Zhang He-Ming  , Hao Yue  ,   School of Microelectronic, Key Laboratory of Ministry of Education for Wide Band-Gap Semiconductor Materials and Devices, Xidian University,Xi,an 710071,China
Published: December 2020

Based on Grove model of CVD(chemical vapor deposition) and Fick’s first law, we propose and build the RPCVD(reduced pressure chemical vapor deposition) growth kinetics model of GeSi/Si heterojunction materials. Different from previous SiGe/Si kinetics model, which only considers surface reaction controlling mechanism, our model simultaneously considers two controlling mechanisms: surface reaction and vapor transport. We also consider the model at these two controlling mechanism limits. This model is suitable for charactering the growth of both strained GeSi/Si heterojunction materials at low temperatures and relaxed GeSi/Si heterojunction materials at high temperatures. The calculated value of the model is compared with experimental results. Whether for the growth of strained SiGe at low temperature of 625 ℃, or for the growth of relaxed SiGe at high temperature of 900 ℃, the model error are both lower than 10%, which is the subject technical target.
Noether-Lie symmetry and conserved quantities of the Rosenberg problem
Authors: Liu Xiao-Wei  , Li Yuan-Cheng  ,   College of Physics Science and Technology, China University of Petroleum (East China)Qingdao 266555,China
Published: December 2020

The Noether-Lie symmetry and conserved quantities of the Rosenberg problem are studied. From the study of the Rosenberg problem,the Noether symmetry and the Lie symmetry for the equation are obtained, thereby the conserved quantities are deduced. Then the definition and the criterion for Noether-Lie symmetry of the Rosenberg problem are derived. Finally,the Noether conserved quantity and the Hojman conserved quantity are deduced from the Noether-Lie symmetry.
Single-step and multiple-step prediction of chaotic time series using Gaussian process model
Authors: Li Jun  , Zhang You-Peng  ,   School of Automation & Electrical Engineering, Lanzhou Jiaotong University, Lanzhou 730070, China
Published: December 2020

For the chaotic time series single-step and multi-step prediction, Gaussian processes (GPs) method based on composite covariance function is proposed. GP priors over functions are determined mainly by covariance functions, and through learning from training data sets, all hyperparameters that define the covariance function and mean function can be estimated by using matrix operations and optimal algorithms within evidence maximum bayesian framework. As a probabilistic kernel machine, the number of tunable parameters for a GP model is greatly reduced compared with those for neural networks and fuzzy models. GP models with different composite covariance functions are applied to chaotic time series single-step and multi-step ahead prediction and compared with other models such as standard GP model with single covariance function, standard support vector machines, least square support vector machine, radial basis functional (RBF) neural networks, etc. Simulation results reveal that GP method with using different composite covariance functions can be used to accurately predict the chaotic time series and show stable performance with robustness. Hence,it provides an effective approach to studying the properties of complex nonlinear system modeling and control.
All-optical multicasting based on multi-pumpfour-wave mixing in photonic crystal fiber
Authors: Hui Zhan-Qiang  , Zhang Jian-Guo  ,   (1)State Key Laboratory of Transient Optics & Photonics, Xi'an Institute of Optics &Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China; (2)State Key Laboratory of Transient Optics & Photonics, Xi'an Institute of Optics &Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China;Xi'an Institute of Posts and Telecommunications, Xi'an 710061, China
Published: December 2020

All-optical multicasting is a key technology of future transparent photonic network, and in this paper it is presented and experimentally demonstrated based on four-wave mixing (FWM) with multi-frequency pump in 100 m dispersion flattened highly nonlinear photon crystal fiber (HNL-PCF). A signal together with double orthogonal pumps is input into the PCF, and four idlers at new frequencies can be generated through degenerate multi-frequency pump FWM processes, which carry the same data information as the input signal and then a 4×10 Gbit/s wavelength multicasting has been obtained with a tunable operation wavelength range of 35.2 nm and total channel span of 4.4THz. The optimal conversion efficiency and the optimal Q factor are -22 dB and 5.3, respectively. The system is transparent to both bit rate and modulation format. The advantage of this scheme consists in the ability of bandwidth, and the multicasting channel scalable due to dispersion flattening of PCF is used. Furthermore, it is all optical fiber, compact and robust, which makes it more competitive as well as easily accessible for the uses in practical optical communication systems.
Stereoscopic visualization based on splitting of two-way polarized image beams
Authors: Dai Yu  , Zhang Jian-Xun  ,   Institute of Robotics and Automatic Information System, Nankai University, Tianjin 300071, China
Published: December 2020

A thin metal film is introduced to split two-way polarized image beams, thereby accomplishing a stereoscopic three-dimensional display. Linearly polarized beams emitted by two uniform liquid crystal displays (LCDs) are reflected and transmitted by ultrathin aluminum film separately. Since optical constant of ultrathin metal film depends on film thickness, a piecewise linear function is used to obtain the relationship between the volume fraction of aluminum and the thickness of the film, and then the optical constant can be estimated by the Sheng Model. Following this procedure it is proved that both the reflected and the transmitted beams become elliptically polarized light beams and their principal axes are approximately vertical. Thus two orthogonal polarizers can be used to separate them and then make the observer have a perception of depth in LCD image. In order to keep the quantities of light entering the observers two eyes balanced, the thickness of the aluminum film is optimized. Experimental results are in agreement with the theoretical analyses, so the correctness of the method is verified.
Magnetically tunable magneto-photonic crystals for multifunctional terahertz polarization controller
Authors: Fan Fei  , Guo Zhan  , Bai Jin-Jun  , Wang Xiang-Hui  , Chang Sheng-Jiang  ,   Key Laboratory of Opto-electronic Information Science and Technology of Ministry of Education, Institute of Modern Optics, Nankai University, Tianjin 300071, China
Published: December 2020

A multifunctional terahertz polarization controller is designed based on the two-dimensional photonic crystal structure and the ferrite material. The different working devices including a controllable polarizer, a polarization beam splitter and a tunable phase retarder with continuous phase retardations of - at 1 THz are controlled by the shift of photonic band gap with different external magnetic fields. By using the plane wave expansion method and the rigorous coupled wave analysis, we calculate the band gap positions and transmittances of device with the variation of magnetic field. The field distribution and phase are simulated by the finite difference time domain method.
Effect of finite-amplitude acoustic wave nonlinear interaction on farfield directivity of sound source
Authors: Lü Jun  , Zhao Zheng-Yu  , Zhou Chen  , Zhang Yuan-Nong  ,   School of Electronic Information, Wuhan University, Wuhan 430079, China
Published: December 2020

The acoustic radiation pressure expression of a multi-frequency sound source is obtained on the basis of the Fenlon theory. Then using the solution method of a monochromatic source harmonic wave directivity, farfield directivity of second-order approximate is obtained in the case of the dual-frequency sound source interaction. Subsequently, the effect of two-wave interaction on the farfield of first-order and second-order wave of either wave is studied and discussed when the initial radiation pressures and frequencies are different. The conclusion is that there are some different effects of sound wave interaction on the farfield directivity of a sound source, when the relative initial radiation pressure and frequency between the sound waves is changed.
Analysis of formation mechanism of Li-like satellites in aluminum plasma and experimental application
Authors: Yu Xin-Ming  , Cheng Shu-Bo  , Yi You-Gen  , Zhang Ji-Yan  , Pu Yu-Dong  , Zhao Yang  , Hu Feng  , Yang Jia-Min  , Zheng Zhi-Jian  ,   School of Physics Science and Technology, Central South University, Changsha 410083, China;,   Research Center of Laser Fusion, China Academcy of Engineering Physics, Mianyang 621900, China
Published: December 2020

Base on the code of steady K-shell model for collision radiative balance, we analyze the main mechanism of populating the Li-like satellite of aluminum plasma in detail. The evolutions of the Li-like satellite intensity ratios of 1s2p2 2P1s22p2P, 1s2s2p(1S)2P1s22s2S and 1s2p2 2D1s22p2P with electron temperature and density are depicted from which we find that the intensity ratio is density sensitive and temperature unsensitive, which can be used to diagnose the electron density in hot dense plasma. At the same time, the evolution of the intensity ratio of He-like to He-like resonant with electron density is also given. The value of the ratio is large in the high electron density region due to the influence of the undistinguished Li-like statellite around the He-like intercombination. Finally, we simulate the spectra emitting from the hot dense aluminum plasmas generated by the Shengguang-Ⅱ equipment and give the electron temperature and density.
Numerical simulation of plasma immersion ion implantation for cubic target with finite length using three-dimensional particle-in-cell model
Authors: Wang Peng  , Tian Xiu-Bo  , Wang Zhi-Jian  , Gong Chun-Zhi  , Yang Shi-Qin  ,   State Key Laboratory of Advanced Welding Production Technology, Harbin Institute of Technology, Harbin 150001, China
Published: December 2020

Plasma immersion ion implantation (PIII) of the square target with finite length is simulated using a three-dimensional particle-in-cell (PIC) plasma simulation in this paper. The incident dose, the impact angle and the implanted energy on the target surface are investigated. The results show that the sheath around the square target with finite length becomes spherical rapidly during PIII. And the three-dimensional sheath width is small apparently compared with the one simulated by two-dimensional PIC. And it is found that the three-dimensional ion dose is not evenly distributed on the target surface during simulation time (50-1pi) in this work. The dose is smallest in the center of the target, and it is largest near the corner. This is due to spherical sheath where ions are focused and accelerated into near the corner. In the central zone, the ion incidence is nearly normal to the surface, and the impact average energy exceeds 90% of the maximum. But the impact angle near the corner is always nearly 45, and the implanted energy is only about 50% of the maximum.
Direct method of determining the lattice parameters of a phase from X-ray diffraction pattern of multi-phase
Authors: Xu Xiao-Ming  , Miao Wei  , Tao Kun  ,   Center for Testing and Analyzing of Materials, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China
Published: December 2020

A new method of determining lattice parameters by peak fitting of X-ray diffraction pattern, without involving structure parameters, is introduced. The method can be applied to a single phase and one phase in multi-phase diffraction patterns. It can avoid getting different fitting results caused by using different extrapolation functions, and can get a more accurate result in a short time. The application program of the method has been used in the practical work. For improving the fitting accuracy, the program can also adjust off-axis deviation of the sample surface and the goniometric mechanical zero.
All-organic two-dimensional photonic crystal laser based on holographic polymer dispersed liquid crystals
Authors: Deng Shu-Peng  , Li Wen-Cui  , Huang Wen-Bin  , Liu Yong-Gang  , Peng Zeng-Hui  , Lu Xing-Hai  , Xuan Li  ,   State Key Laboratory of Applied Optics, Changchun Institute of Optics, Fine Mechanics and Physics,Chinese Academy of Sciences, Changchun 130033, China;,   Graduate University of Chinese Academy of Sciences, Beijing 100049, China
Published: December 2020

In this paper, we report a kind of dye-doped two-dimensional photonic crystal based on holographic polymer dispersed liquid crystals (HPDLC) with a lattice constant of 582nm, which is prepared conveniently with a single step holographic exposure. Under the excitation of a frequency-doubled Nd:yttrium-aluminum-garnet laser operating at a wavelength of 532nm, optically pumped lasing with narrow bandwidth and low threshold is observed from a 4-(dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4H-pyran dye-doped two-dimensional photonic crystal. The results show that the emitted lasing peak is centered at about 603nm with a full width at half maximum of only 0.4nm, and the threshold energy is about 22.7 J, which is evidently lower than the reported previously. The laser bandwidth decreases by a factor of three from 1.4nm to 0.4nm compared with that of the dye-doped HPDLC transmission grating. This result exhibits a bright prospect in application of tunable photonic crystal laser.
Influence of interface traps of p-type metal-oxide-semiconductor field effect transistor on single event charge sharing collection
Authors: Chen Jian-Jun  , Chen Shu-Ming  , Liang Bin  , Liu Bi-Wei  , Chi Ya-Qing  , Qin Jun-Rui  , He Yi-Bai  ,   School of Computer Science, National University of Defense Technology, Changsha 410073, China
Published: December 2020

Due to negative bias temperature instability and hot carrier injection, p-type metal-oxide-semiconductor field effect transistor (MOSFET) will degrade with time, and the accumulation of interface traps is one major reason for the degradation. In this paper, the influence of the accumulation of pMOSFET interface traps on single event charge sharing collection between two adjacent pMOSFET is studied based on three-dimensional numerical simulations on a 130 nm bulk silicon complementary metal-oxide-semiconductor process, the results show that with the accumulated interface traps increasing, the charge sharing collection reducs for both the two pMOSFETs. The influence of the accumulation of pMOSFET interface traps on single event charge sharing induced multiple transient pulses between two adjacent inverters is also studied, the results show that the multiple transient pulses induced by the two pMOSFET charge sharings will be compressed, while multiple transient pulses induced by the two nMOSFET charge sharing will be broadened.
Lattice dynamical, dielectric and thermodynamic properties of LiNH2 from first principles
Authors: Li Xue-Mei  , Han Hui-Lei  , He Guang-Pu  ,   School of Physics and Electronic Engineering, Leshan Normal University, Leshan 614000, China;,   School of Mathematics, Sichuan University, Chengdu 610064, China
Published: December 2020

The lattice dynamical, dielectric properties and thermodynamic properties of LiNH2 are investigated by first principles calculations. Based on the density functional perturbation theory within the framework of linear response theory, the phonon dispersion curves and the phonon density of phonon states throughout the Brillouin zone are obtained. The calculated frequencies of the Raman active and infrared active modes are compared with previous experimental and theoretical results, and Born effective charge tensor as well as electronic dielectric permittivity tensor is presented. We find that the Born effective charge tensor of LiNH2 has quite small anisotropy. These calculated results are in good agreement with available experimental and theoretical values. Furthermore, the thermodynamic functions are predicted using the phonon density of states.
Transport characteristic of photoelectrons in uniform-doping GaAs photocathode
Authors: Ren Ling  , Chang Ben-Kang  , Hou Rui-Li  , Wang Yong  ,   Institute of Electronic Engineering and Optoelectronic Technology, Nanjing University of Science and Technology, Nanjing 210094, China
Published: December 2020

The transport of photoelectrons in a uniform-doping transmission-mode GaAs photocathode is calculated by establishing the models of atomic configuration and ionized impurity scattering. And the influence of the doping concentration of photocathode, the photocathode thickness, the electron diffusion length on the diffused circle and the ratio of the number of photoelectrons reaching the emit-surface to the number of exited photoelectrons at the back-interface of GaAs photocathode are analyzed. The calculated results show that the limiting linear resolution is 769 mm-1 with the cathode thickness being 2 m, the electron diffusion length 3.6 m and the uniform-doping concentration 11019 cm-3. The research on the transport of photoelectrons is worthwhile for preparing the high-performance GaAs cathode and improving the resolution of intensifier image.
Surface-plasmon-mediated emission enhancement from Ag-capped ZnO thin films
Authors: Qiu Dong-Jiang  , Fan Wen-Zhi  , Weng Sheng  , Wu Hui-Zhen  , Wang Jun  ,   Department of Physics, Zhejiang University, Hangzhou 310027, China
Published: December 2020

Ag/ZnO bilayer thin films are fabricated on Si substrates via two-step approach of ZnO sputtering + Ag evaporation. The enhancement of the near band edge (NBE) emission of the ZnO film is realized through coupling between the surface plasmon resonating energy at Ag/ZnO interface and the photonic energy of ZnO NBE emission. The dependence of the emission enhancement ratio of ZnO on the thickness and the growth temperature T of Ag cap-layers are investigated. By evaporating Ag(8 nm) cap-layer onto ZnO(100 nm) film at high substrate temperatures (T300 ℃), the value reaches about 18,i.e., 18, which is more than twice that of Ag(8 nm)/ZnO(100 nm) bilayer films grown at low temperatures (T200 ℃). It is found that the realization of the larger can be ascribed to the bigger surface roughness of Ag/ZnO bilayer samples prepared under higher growth temperatures.
Preparation and structure characterization of Pd thin films by supercritical fluid deposition
Authors: Wang Yan-Lei  , Zhang Zhan-Wen  , Li Bo  , Jiang Bo  ,   College of Chemistry, Sichuan University, Chengdu 610064, China;,   Key Laboratory of National Defense Science and Technology for High-Temperature and High-Density Plasma Physics, Reserch Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900, China
Published: December 2020

Pd films are deposited on the Si wafers by the reduction of palladium(Ⅱ) hexafluoroacetylacetonate, which is used as the precursor, in the supercritical CO2 solution at temperature 100 ℃ and pressures between 12 and 18 MPa, and with reaction for 1020 h. The films are continuous, uniform and 0.31.5 m thick. The analyses of the Pd films by X-ray photoelectron spectroscopy and X-ray diffraction indicate that the structures of the deposited films are of single matter and nanocrystalline. The scanning electron microscope images show that pressure is a factor of affecting the size of the grain of the deposited film. At a pressure of 12 MPa, the size of grain is between 30 and 60 nm, at a pressure of 15 MPa, it is between 90 and 120 nm. Moreover, at a pressure of 18 MPa, it is between 150 and 180 nm. At the same temperature, with higher pressures, the size of the grain is bigger. On the same conditions, Pd thin films are deposited on the inner and the outer surfaces of cylindrical cavity.
Influence of annealing on thermal stability of IrMn-based magnetic tunnel juctions
Authors: Yan Jing  , Qi Xian-Jin  , Wang Yin-Gang  ,   College of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
Published: December 2020

The magnetic tunnel junction with a structure of IrMn/CoFe/AlOx/CoFe is deposited by magnetron sputtering and annealed at different temperatures in a magnetic field of parallel to the orienting field. Vibrating sample magnetometer is used to record the magnetic hysteresis loop at room temperature, and scanning probe microscope is used to record the interface morphology. The influence of annealing on thermal stability of the magnetic tunnel junction is investigated by holding the film in its negative saturation field. After annealing, the exchange bias increases due to the enhancement of unidirectional anisotropy of antiferromagnetic layer. The recoil loop of the pinned ferromagnetic layer shifts towards the positive field, and the exchange bias field decreases monotonically, with the film held in a negative saturation field, whereas annealing reduces the reduction speed of Hex.
An X band synthesizer for a few hundred megawatt level power microwaves
Authors: Fang Jin-Yong  , Huang Hui-Jun  , Zhang Zhi-Qiang  , Zhang Xiao-Wei  , Zhang Li-Jun  , Zhang Qing-Yuan  , Hao Wen-Xi  , Huang Wen-Hua  , Jiang Wei-Hua  ,   Department of Electrical Engineering, Tsinghua University, Beijing 100084, China;,   Northwest Institute of Nuclear Technology, Xi'an 710024, China
Published: December 2020

A synthesis method for a few hundred megawatt level power microwave is presented in this paper. Based on the coupling wave theory and the polarized wave orthogonal theory, the pulse series of one gigawatt level power microwave and one hundred megawatt level power microwave can be put in two separate ports and put out from one common port. The synthesizer is unitized by two cylindrical waveguides which are back to back combined; the cylindrical waveguide which is joined with the output port is named main channel, and the other cylindrical waveguide is called associate channel. The main channel transmits horizontally polarized TE011 mode microwave, and the operation frequency band is only limited to the barrier frequency c. The associate channel transmits vertical polarized TE011 mode microwave, and the operation frequency band can reach up to several hundred mega hertz. High power experiment indicates that the transmission energy efficiency of the main channel is nearly 100% and the coupling energy efficiency of the associate channel is above 87%, the power capacity of the main channel is more than 1GW and that of the associate channel is about 300 MW.
Effect of 3,4,9,10-perylenetetracarboxylic dianhydride on the performance of ZnO nanorods/polymer hybrid solar cell
Authors: Yan Yue  , Zhao Su-Ling  , Xu Zheng  , Gong Wei  , Wang Da-Wei  ,   Key Laboratory of Luminescence and Optical Information of Ministry of Education, Institute of Optoelectronics Technology, Beijing Jiaotong University, Beijing 100044, China
Published: December 2020

ZnO nanoroods/poly (MEH-PPV) hybrid solar cells are fabricated and their properties are discussed. In order to improve the absorption of sunlight, a layer of 3,4,9,10-perylenetetracarboxylic dianhydride(PTCDA) is inserted between ZnO nanorods and MEH-PPV, and cells with the structure ITO/ZnO nanorods/PTCDA/MEH-PPV/Au are prepared with different thickness values of PTCDA. After introducing PTCDA, the devices show a strong and broad absorption in visible region, which increases the number of photo-induced excitons and thus results in an enlarged photocurrent. When the thickness of PTCDA is 40 nm, we can observe the smooth morphology of thin layer surface, and achieve the best performance of the device.
Modeling of ultraviolet characteristics of deep space target
Authors: Yuan Yan  , Sun Cheng-Ming  , Huang Feng-Zhen  , Zhao Hui-Jie  , Wang Qian  ,   Key Laboratory of Precision Opto-mechatronics Technology of Ministry of Education, Beijing University of Aeronautics and Astronautics, Beijing 100191, China
Published: December 2020

Ultraviolet detection has advantages of high sensitivity and low false alarm rate. Analysis of ultraviolet characteristics has great significance for space target detection. An accurate modeling method is proposed for the ultraviolet characteristics of space target. Based on the background environment and material properties of space target, region and grid division are generated, and the mathematical model of ultraviolet characteristics of space target is established by introducing bidirectional reflectance distribution function. The position relations of target, detector and background radiation source are determined by coordinate transformation algorithm. The calculation flow for ultraviolet characteristics of space target is derived. Finally, the observed ranges and irradiation distributions of Ziyuan-1 and Fengyun-3 satellite are calculated by the given parameters. The simulation results demonstrate the validity of the modeling method.
Study and realization of local frequency estimation algorithm in magnetic resonance elasto-graphy based on dual-bandwidth Gaussian filters
Authors: Yu Jie  , Wang He  , Cai Xiao-Yun  , Zhang Xue-Long  , Huang Qing-Ming  , Huang Yong  , Wang Xiao-Yan  , Lu Lun  , Li Geng-Ying  , Cheng Hong-Yan  , Wang Hong-Zhi  , Chen Qi-Te  ,   (1)Eastern Hepatobiliary Surgery Hospital, Second Military Medical University, Shanghai 200438, China; (2)GE Healthcare (China), Shanghai 201203, China; (3)Institute of Medical Imaging Technology, University of Shanghai Science and Technology, Shanghai 200093, China; (4)Institute of Medical Imaging Technology, University of Shanghai Science and Technology, Shanghai 200093, China;Shanghai Medical Instrumentation College, Shanghai 200093, China; (5)Shanghai Key Laboratory of Magnetic Resonance, De
Published: December 2020

In the present study we analyze the biomechanical properties of life-form parenchyma, derive the relationship between MR displacement-phase image and the elasticity of life-form parenchyma, thereby study the local frequency estimation(LFE) algorithm. Finally the algorithm is relized by Matlab, and the inversion results of phantom MRE image demonstrate the effectiveness of the LFE algorithm, which would form a basis for subsequent research on liver fibrosis classification .
Allocation of multi-objective cross-layer wireless sensor network resource based on chaotic parallel genetic algorithm
Authors: Zhou Jie  , Liu Yuan-An  , Wu Fan  , Zhang Hong-Guang  , Zu Yun-Xiao  ,   School of Electronic Engineering, Beijng University of Posts and Telecommunications, Beijing 100876, China
Published: December 2020

A chaotic parallel genetic algorithm for the allocation of a multi-objective cross-layer wireless sensor network resource is provided, in which chaotic sequence and parallel genetic algorithm are used to dynamically adjust target selection, communication time slots and other parameters for optimizing the global cross-layer resource allocation. Simulations are conducted to compare the chaotic parallel genetic algorithm method with random allocation algorithm, dynamic programming algorithm, T-MAC protocol and the S-MAC protocol separalely. The simulation results show that the chaotic parallel genetic algorithm has a small communication delay and high success rate of target detection, which reduces the power consumption and improves the real-time characteristic of wireless sensor network.
Research on synthesis methodology of piecewise linear chaotic circuit
Authors: Li Guan-Lin  , Chen Xi-You  ,   Department of Electrical Engineering, Dalian University of Technology, Dalian 116023, China
Published: December 2020

Chaotic oscillator can be produced by a single piecewise-linear element connected to a linear circuit. In this paper, the process of synthesizing the piecewise-linear chaotic circuit is discussed. Firstly, The parameters of the nonlinear element and the admittance function of the one-port circuit are determined by the eigenvalues of the system. Secondly, the one-port circuit is designed according to the admittance function. The one-port circuit can be realized with two kinds of basic admittance functions in parallel. The inductance and the capacitance of the circuit are always positive, and the negative resistances are always commonly grounded. Finally, the example of synthesizing chaotic circuit with the proposed method in presented.
Blind detection algorithm of complex multi-valued discrete Hopfield network
Authors: Zhang Yun  , Zhang Zhi-Yong  ,   College of Automation, Nanjing University of Posts & Telecommunications, Nanjing 210003, China
Published: December 2020

A novel complex multi-valued discrete Hopfield neural network (CMDHNN) is proposed in this paper. A multi-valued discrete activation function and a new energy function for CMDHNN are constructed. The stabilities for multi-valued CMDHNN with asynchronous and synchronous operating modes are also analyzed seperately. The special energy functions own the ability to describe the dynamic characteristics of CMDHNN which the energy functions of existing references cannot explain. Meantime, these energy functions can make the true source signal vector correspond to the minimum point of the energy function of CMDHNN. Furthermore, to verify effectiveness of CMDHNN, the weighted matrix of CMDHNN is constructed by the specific cost function for the blind detection of signals. Simulation results show that the proposed CMDHNN can be used to blindly detect the dense MQAM constellation signals with shorter received signals and the global minimal value of the CMDHNN energy function is verified.
Comprehensive Survey for the Frontier Disciplines Latest advances in THz coherent light source pumped by 600—2000 nm waveband pumped source
Authors: Qi Chun-Chao  , Ouyang Zheng-Biao  ,   THz Technical Research Center of Shenzhen University,Shenzhen 518060, China; Shenzhen Key Laboratory of Micro-Nano Photonic Information Technology, Shenzhen 518060, China; College of Electronic Science and Technology, Shenzhen University, Shenzhen 518060, China
Published: December 2020

Recently, due to the potential applications, the developing of compact, portable, low cost, and tunable THz wave became a research focus of THz technology. The light source with a wavelength range from 600—2000 nm frequently serves as a pumped source of THz wave due to its property of compact size, low cost, tunable frequency and stable operation. In this paper, tunable dual-wavelength continuous-wave pumping source and THz generator with an internal-cavity optical parameter oscillator are overviewed and analyzed in detail. It is shown that pumping source in the near-infrared wave band is more advantageous than those in the mid-infrared wave band for compactness in size. It is also shown that the difference frequency and nonlinear cascade processes have become an important way to generate THz radiation for wide tuning merit in such a system.
Influences of laser bandwidth and intensity on laser ionization of isotope atoms
Authors: Fan Feng-Ying  , Wang Li-Jun  ,   Department of Engineering Physics, Tsinghua University, Beijing 100084, China
Published: December 2020

The ionization process of the interaction of nonmonochromatic laser with isotope atom system is studied. The multimode laser field is described by a stochastic model of chaotic field. By using the Fokker-Planck equation, the excited dynamic equation ofinteraction of the finite-bandwidth chaotic fields with K-level atom is derived. The influences of laser bandwidth and intensity on ionization efficiency and selectivity of three-level isotope atoms are also discussed.
Effect of framework flexibility on diffusion of short alkanes in metal-organic framework
Authors: Xiang Hui  , Liu Da-Huan  , Yang Qing-Yuan  , Mi Jian-Guo  , Zhong Chong-Li  ,   College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029, China
Published: December 2020

Molecular dynamics simulations is performed to study the diffusion of several short alkanes in a flexible and rigid metal-organic framework, IRMOF-1. The results show that the self-diffusivities of alkanes in the flexible framework are larger than in a rigid framework and the activation energies in the flexible framework are less than in the rigid framework. The effect of framework flexibility on the self-diffusiviy increases with temperature inereasing and loading or chain length decreasing. Therefore, in the study of the diffusion behavior of alkanes in the metal-organic framework materials using molecular simulation method, especially for the case of the high temperature and shorter alkane molecules, flexible force field may give more reasonable results.
Detection of carrier-envelope offset frequency in an Er-doped fiber femtosecond laser
Authors: Li Tian-Chu  , Cao Shi-Ying  , Meng Fei  , Cai Yue  , Fang Zhan-Jun  , Wang Gui-Zhong  , Zhang Zhi-Gang  ,   (1)Division of Electricity and Quantum Metrology, National Institute of Metrology, Beijing 100013, China; (2)Institute of Quantum Electronics, School of Electronics Engineering and Computer Science, Peking University, Beijing 100871, China
Published: December 2020

It is the inevitable trend of the development for the optical frequency comb based on the Ti: sapphire femtosecond laser to be replaced by that based on the Er: fiber femtosecond laser. The detection of the carrier-envelope offset f0 in the femtosecond laser is a key to the realization of an optical frequency comb. In this paper, the structure of the optical part of an Er: fiber optical frequency comb is introduced. The optical pulses from an Er: fiber femtosecond laser with a repetition of 230 MHz are first amplified with a two stage amplifiers, spectrally broadened in a highly nonlinear fiber, and then pass through a single-beam f—2f self-referencing interferometer. By optimizing the optical parameters, the f0 with a signal-to-noise ratio of 30 dB is obtained in the Er: fiber femtosecond laser, which is favorable for the realization of an Er: fiber frequency comb.