bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of thickness of epitaxial PbZr0.4Ti0.6O3 film on the physical properties
Authors: Wang Ying-Long  , Wei Tong-Ru  , Liu Bao-Ting  , Deng Ze_Chao  ,   河北大学物理科学与技术学院，保定 071002
Published: December 2020

The thickness dependence of the spontaneous polarization and the hysteresis loop of epitaxial PbZr0.4Ti0.6O3 thin films deposited on (001) SrTiO3 substrate was investigated via the Landau-Devonshire's phenomenological theory considering the coupling of the stress field of the edge dislocation and the polarization. The results show that the critical thickness for the formation of misfit dislocation is ～1.27nm, and there is a drastic variation in the polarization near the dislocation in films with thickness greater than the critical value, which results in the formation of the dead layer that severely degrades ferroelectric properties. With decreasing the film thickness, both the dislocation spacing and the ratio of the dead layer to film total thickness increase. The thickness dependence of the hysteresis loop indicates that the remnant polarization decreases as the thickness decreases.
Study on FN-DLC thin films：(Ⅲ) hydrophobic nature analysis
Authors: Xiao Jian-Rong  , Xu Hui  , Deng Chao-Sheng  , Wang Huan-You  , Li Yan-Feng  ,   (1)中南大学材料科学与工程学院，长沙 410083; (2)中南大学物理科学与技术学院，长沙 410083; (3)中南大学物理科学与技术学院，长沙 410083；中南大学材料科学与工程学院，长沙 410083
Published: December 2020

Nitrogen doping of fluorinated diamond-like carbon (FN-DLC) films were deposited on p-type (100) silicon wafers at different deposition condition. The contact angle of water on the FN-DLC films surfaces was measured by a sessile-drop method. The surface morphology of films was characterized by atomic force microscopy (AFM). The Raman spectrum, infrared spectrum and X-ray photoelectron spectrum (XPS) demonstrate that the hydrophobic nature of FN-DLC films lies on chemistry structure, polarization intensity and roughness of films surface. As the ratio of sp3/sp2 decreases, the quantity of CF2 and roughness of film surface increases, thus contact angle increases. Otherwise, contact angle decreases. The contact angle is correlated with the deposition condition, which low temperature, low radio frequency power and high flux ratio r(r=CF4/［CF4+CH4］) brings the contact angle to ascend.
Finite element simulation of laser-generated circumferential waves in hollow cylinder
Authors: Zhao Yan  , Shen Zhong-Hua  , Lu Jian  , Ni Xiao-Wu  ,   南京理工大学理学院，南京  210094
Published: December 2020

Based on the thermoelastic mechanism of laser ultrasonic, a finite element model for simulating laser-generated circumferential wave in a hollow cylinder is developed. A control calculation is executed to verify the correctness of the model according to the study of Gao et al (J. Appl. Phys. 91, 6114 (2002)). Our calculated results are in good agreement with the experimental signals obtained by Gao et al. And then, the circumferential waves induced by line laser source in hollow cylinders with different thicknesses and different radii are simulated and typical results are presented. Based on the numerical calculations, the difference between circumferential guided waves in hollow cylinder and Lamb waves in a plate, and the influence of the thickness and radius on the circumferential waves are discussed in detail.
Method of fusing dual-spectrum low light Level images based on gray-scale spatial correlation
Authors: Zhang Chuang  , Bai Lian-Fa  , Zhang Yi  ,   南京理工大学电光学院,南京 210094
Published: December 2020

Gray-scale spatial correlation reflects the definition of images, and the main purpose of fusing images is to improve the definition of images. Based on the spectrum characteristics of low light level (LLL) whole-wave image and LLL short-wave image and the analysis of the one-dimension at gray-scale histograms and the two-dimensional gray-scale spatial correlation charts of LLL whole-wave image and LLL short-wave image, the new method of fusing dual-spectrum LLL images based on gray-scale spatial correlation is proposed. The method is realized by gray-scale selection based standard deviation and gray-scale statistics balance, and the method can effectively improve the definition of images and is easy to execute on hardware compared with gray-scale modulation method and spectrum-field method. The theorefical expressions of the fusion method are expatiated particularly, and the experiment results with different scenes are analyzed.
A 8-neighborhood based generalized Hough transform for fragmented graphics recognition
Authors: Li Zhi-Lei  , Zhai Hong-Chen  , Wang Ming-Wei  ,   南开大学现代光学研究所，光电信息技术科学教育部重点实验室，天津 300071
Published: December 2020

This paper proposes a 8-neighborhood based generalized Hough transform (SGHT) method developed from the existing generalized Hough transform (GHT) method. The difference chiefly shows in the process of generating the Reference-Table and recognizing the graphics. The new method resolves the difficulty in the process of recognizing fragmented graphics from images by conventional GHT, which can be employed not only in the un-fragmented graphics recognition but also in the fragmented graphics recognition with significant precision and rapidity. The effectiveness of ENHT has been proved in our experiments.
A new broadband fiber light source for optical coherence tomography
Authors: Liang Yan-Mei  , Zhou Da-Chuan  , Meng Fan-Yong  , Wang Ming-Wei  ,   (1)南开大学现代光学研究所，光电信息技术科学教育部重点实验室，天津 300071; (2)天津爱天光电子科技有限公司，天津 300384
Published: December 2020

A new type of Gaussian-like broadband superfluorescent fiber light source suitable for optical coherence tomography (OCT) is introduced in this paper. Erbium-doped optical fiber simultaneously pumped by 980nm laser diode (LD) and 1480 nm LD is used as the gain medium. Both optical controllers and temperature controllers are employed to adjust the output of LDs and to improve the stability of output power of light source. A fiber coupler with a specific splitting ratio plus multi-stage long period fiber gratings are used to modulate the output spectrum so that the spectral profile of the broadband light source is near Gaussian. The output power is about 27mW with center wavelength at 1.57μm and the bandwidth over 75 nm. The experiment results reveal that the sidelobes of the autocorrelation function of the output spectrum are effectively suppressed, which can meet the need of optical coherence tomography.
Determination of the region where Si nanoparticles form during pulsed laser ablation
Authors: Chu Li-Zhi  , Lu Li-Fang  , Wang Ying-Long  , Fu Guang-Sheng  ,   河北大学物理科学与技术学院,保定 071002
Published: December 2020

To determinate the nucleation region of Si nanoparticles formed in gas phase, the single crystalline Si target with high resistivity was ablated by a XeCl excimer laser in pure Ar gas under the ambient pressure of 10Pa, and the nanocrystalline Si films were systemically deposited on pieces of glass or single crystalline (111) Si substrates lined up at a distance of 2.0cm under the plasma. The Raman and X-ray diffraction spectra, scanning electron microscope and atomic force microscope images of the films show that Si nanoparticles were formed on the pieces placed at horizontal distances 0.5 to 2.8cm from the target, the average size of Si nanoparticles monotonically decreased with the distance increasing. The region that Si nanoparticles form in gas phase was estimated on the basis of the PLA dynamics.
Formation mechanism of GaP nanorods under mild Benzene-thermal condition
Authors: Fang Kun  , Gao Shan-Min  , Jiang Wei  , Zhang Jiang  , Cao Chuan-Bao  , Zhu He-Sun  ,   (1)北京理工大学材料科学研究中心，北京 100081; (2)烟台师范学院化学与材料科学学院，烟台 264025
Published: December 2020

GaP nanorods with widths of 20—40nm and lengths of 200—500nm, and nanoparticles with diameters of 20—40nm were synthesized via the mild benzene-thermal route, using Na, P and GaCl3 as the starting materials. X-ray powder diffraction, Transmission electron microscopy and X-ray photoelectron spectroscopy were used to characterize the morphology and crystal structure of the products. The results indicated that when the reaction temperature is lower than 250℃, the products consist almost is GaP nanorods. The nanorods change into nanoparticles gradually with increasing temperature. When the reaction temperature exceed 280℃, the products are regularly particles. The reaction proceeds through a metallic gallium intermediate and a solution-liquid-solid mechanism is proposed for the one-dimensional growth.
Surface acoustic wave properties of ZnO films grown by magnetron sputtering
Authors: Yang Guang  , Paulo V. Santos  ,   (1)Paul-Drude固体电子学研究所，柏林 D-10117，德国; (2)华中科技大学武汉光电国家实验室激光科学与技术研究部，武汉 430074;华中科技大学光电子科学与工程学院，武汉 430074;Paul-Drude固体电子学研究所，柏林 D-10117，德国
Published: December 2020

In this letter we report the fabrication and structural properties of ZnO thin films grown on GaAs，Au/GaAs，Si and glass substrates by rf magnetron sputtering. The x-ray diffraction data indicated that all the ZnO films were pure c-axis oriented and the rocking curves showed that the full-width at half maximum(FWHM) of ZnO(002) peak of ZnO/Au/GaAs films is as small as 2.41°. The SEM images showed better surface for the ZnO films grown with Au buffer. The surface acoustic wave properties of IDT/ZnO/GaAs filter were measured by HP8753C network analyzer. The results indicated that the insertion loss is only 10.4dB and the electric efficiency can be up to 84.1% using the 5.6μm-wavelength IDT.
The resonant magnetoelectric response of magnetostrictive/piezoelectric laminated composite under the consideration of losses
Authors: Yang Fan  , Wen Yu-Mei  , Li Ping  , Zheng Min  , Bian Lei-Xiang  ,   重庆大学光电工程学院，国家教育部光电技术及系统重点实验室,重庆 400030
Published: December 2020

The theoretical analysis of resonance magnetoelectric(ME) performances in longitude-transverse type magnetostrictive/piezoelectric laminated composite is presented in this paper based on the equivalent circuit method, and the formula of ME voltage coefficient is obtained, which is useful to the composite design and optimization. To evaluate the ME voltage coefficient near the resonance, the losses such as eddy-current loss, mechanical loss, and dielectric loss are considered and formulated, which indicates that the mechanical loss plays the key role in dissipation. The analysis, which takes losses into account, gives better explanations to current experimental values.
Infulence of electron temperature on the two peaks of Thomson scattering ion-acoustic waves in laser plasmas
Authors: Yu Quan-Zhi  , Li Yu-Tong  , Jiang Xiao-Hua  , Liu Yong-Gang  , Wang Zhe-Bin  , Dong Quan-Li  , Liu Feng  , Zhang Zhe  , Huang Li-Zhen  , C. Danson  , D. Pepler  , Ding Yong-Kun  , Fu Shi-Nian  , Zhang Jie  ,   (1)Central Laser Facility,Rutherford Appleton Laboratory,Didcot,OX110QX,UK; (2)中国工程物理研究院高温高密度等离子体物理国际重点实验室，绵阳  621900; (3)中国科学技术大学近代物理系，合肥  230027; (4)中国科学院高能物理研究所加速器中心，北京  100049; (5)中国科学院物理研究所光物理实验室，北京  100080; (6)中国科学院物理研究所光物理实验室，北京  100080;中国科学院高能物理研究所加速器中心，北京  100049
Published: December 2020

With the effective Thomson scattering diagnostic of the laser plasmas produced under different laser conditions, the distinct asymmetry of the two peaks of the ion-acoustic waves are measured 150 μm in front of the target surface. The more intense peak appears at shorter wavelength when the electron temperature is higher, and switches to longer wavelength when the electron temperature is lower. The two-peak strcture, the asymmetry and the position of the more intensity peak of the ion-acoustic waves can be well interpreted with the Raman scattering effect. This paper, for the first time, establishes the corresponding relationship between Raman scattering of light and Thomson scattering of electons in laser plasmas.
Influence of virtual networks to internet collective behavior
Authors: Wang Lei  , Zhou Shu-Hua  , Yuan Jian  , Ren Yong  , Shan Xiu-Ming  ,   清华大学电子工程系，北京  100084
Published: December 2020

A virtual network is defined as a logical network, in which users exhibit their access behaviors. Virtual networks rely on physical computer networks like the Internet, but have different topologies, and cause significant influence on the physical networks. In this paper, a novel two-tier model is proposed to study influences of virtual networks to Internet collective behavior. It is shown that the queue lengths of the node data packets present phase transition characteristics. Moreover, the phase transition critical point moves to the left and network performance is deteriorated. In a free flow, the nodes are independent of each other or short-range correlative. In the critical state, the nodes are long-range correlative, and there exists a higher power exponent H which means stronger long-range correlation. When the system state is on the right of critical point, virtual network behaviors make the network to present consistent long-range correlative characteristic.
Algebraic dynamical algorithm for numerical solution of artificial earth satellite motion equation
Authors: Lu Wei-Tao  , Wang Shun-Jin  , Zhang Hua  ,   四川大学物理科学与技术学院理论物理中心，成都 610064
Published: December 2020

Algebraic dynamical algorithm is used to solve numerically the artificial earth satellite motion equation for the first time, and the result is compared with Runge-Kutta algorithm and symplectic algorithm under the forth order. The result shows that algebraic dynamical algorithm has higher accuracy than the others in the long-term calculation of satellite orbit. We also discussed the quadrupole and octupole deformation of the Earth's impact on the satellite orbit.
Diagnostic study on the electron density distribution of microwave plasma jet in vacuum environment
Authors: Yang Juan  , Liu Wen-Yi  , Zhu Guo-Qiang  , Mao Gen-Wang  ,   西北工业大学航天学院，西安  710072
Published: December 2020

In order to diagnose precisely the electron number density of microwave plasma jet in vacuum environment, the integrative probe whose function is the same as that of emissive and Langmiur ones was applied to measure the plasma space potential and its current and voltage property when the probe is charged by the electric power of emissive probe and scanning electric power separately. According to the plasma space potential, saturated current on the current-voltage curve of plasma can be determined, which can be used to estimate the number density of electrons. The experimental results show that the number density of electrons in microwave argon plasma jet in vacuum environment is 1×1016—7.2×1016/m3, when the vacuum pressure is 3.2 and 5.4 Pa, the microwave output power is under 60 W and gas mass flow rate is in the range of 42—106 mg/s.
Real-time low-frequency vibration phase drift tracking and auto-compensation in phase-coded quantum key distribution system
Authors: Guo Bang-Hong  , Lu Yi-Qun  , Wang Fa-Qiang  , Zhao Feng  , Hu Min  , Lin Yi-Man  , Liao Chang-Jun  , Liu Song-Hao  ,   (1)华南师范大学光子信息技术广东省高校重点实验室，广州 510006; (2)华南师范大学光子信息技术广东省高校重点实验室，广州 510006;广东茂名学院计算机与电子信息学院，茂名 525000
Published: December 2020

Phase drift caused by environment is the main source of quantum bit error rate and instability in the double M-Z interferometer quantum key distribution(QKD) system. The phase drift consists of both high-frequency and low-frequency vibrations, the former, which is due to environment noise, is usually conducted via the atmosphere and can be isolated by technological measures (e.g. using foamed-plastics wrapping or rubber pillow ), the latter comes from building-vibration, which vibrates slowly with a serious impact on M-Z interferometer, with a period of 3±0.32 min (min level). A novel real-time tracking and compensation method for phase drift caused by low-frequency vibration is proposed. With the improved scheme, the QKD system based on double M-Z interferometers can operate stably for 24 hours, and key exchange with an error below 6% over 75 kilometers has been achieved in the lab.
Massive particle quantum tunneling radiation of Barriola-Vilenkin black hole with global monopole
Authors: Meng Qing-Miao  , Su Jiu-Qing  , Jiang Ji-Jian  ,   菏泽学院物理系，菏泽 274015
Published: December 2020

The quantum tunneling framework is adopted to investigate tunneling radiation of Barriola-Vilenkin black hole with a global monopole. We obtain a conclusion that the emission rate of massive particles is related with the change of Bekenstein-Hawking entropy. The emission rates of massless and massive particles take the same functional form. It is consistent with the underlying unitary theory.
Adiabatic Landau-Zener tunnelling in nonlinear three-level system
Authors: Wang Guan-Fang  , Liu Bin  , Fu Li-Bin  , Zhao Hong  ,   (1)北京应用物理与计算数学研究所，北京 100088; (2)北京应用物理与计算数学研究所，北京 100088;兰州大学物理科学与技术学院理论物理研究所，兰州 730000; (3)兰州大学物理科学与技术学院理论物理研究所，兰州 730000;厦门大学物理系，厦门 361005
Published: December 2020

We investigate adiabatic Landau-Zener tunnelling in nonlinear three-level system. The levels and tunnelling probability are studied with respect to the nonlinearity. For weak nonlinearity, the structures of the levels are smooth and similar to their linear counterparts. However the eigenstates of the middle-level will be unstable for some system parameters, which leads to the adiabaticity to break down and the tunnelling probability chaotic. For strong nonlinearity, the structures of the levels are distorted, including double-ring-like distortion in lower-level and butterfly-like distortion in upper-level. The adiabaticity will be broken down more badly. Finally we give a possible application of the system in triple-well trapped Bose-Einstein condensates.
Simulation study of effects of initial melt temperature on microstructure of liquid metal Na during solidification processes
Authors: Hou Zhao-Yang  , Liu Rang-Su  , Wang Xin  , Tian Ze-An  , Zhou Qun-Yi  , Chen Zhen-Hua  ,   (1)湖南大学材料科学与工程学院，长沙  410082; (2)湖南大学应用物理系，长沙  410082; (3)湖南大学应用物理系，长沙  410082;湖南大学材料科学与工程学院，长沙  410082
Published: December 2020

Molecular dynamics simulation study has been performed on the effects of thermal history of initial melt temperature on microstructures during solidification of liquid metal Na. The pair distribution function g(r) curves, the bond-type index method and the cluster-type index method have been used to analyze the variations of microstructures during the solidification process. The results show that the solidification structures of liquid metal Na at the cooling rate of 1×1011 K/s with different initial melt temperatures are always crystalline. The 1661 and 1441 bond-types or the bcc basic cluster (14 6 0 8) in the system play the critical role in the microstructure transitions. At the same time, it has been found that the effects of initial melt temperature on solidification microstructures are very remarkable, while they are not obvious in liquid and supercooled states, and the effects can be fully displayed only near the crystallization temperature Tc. The results also demonstrate that the effects of initial melt temperature on the crystallinity of solidification structures are different for different initial melt temperatures. Although the degree of influence is not linearly varying with the decrease of initial melt temperature, it still demonstrate that the influence degree can be controlled through the change of initial melt temperature. The cluster-type index method more clearly describes the cluster configurations in crystal system than the bond-type index method, so it is valuable to deeply investigate the evolution mechanisms of microstructures in liquid metal during solidification processes.
Control of gyro system based on lowpass filter function feedback
Authors: Du Lin  , Xu Wei  , Jia Fei-Lei  , Li Shuang  ,   西北工业大学理学院应用数学系，西安 710072
Published: December 2020

This paper presents a method of controlling gyro system based on bounded damping feedback. Firstly，using LaSalle invariable theorem，a stability analysis is given theoretically. Then by introducing a two order Butterworth lowpass filter，a feedback controller is proposed on the basis of measured signals. The chaotic gyro system can be stabilized to different periodic obits or fixed points in the numerical simulation. Furthermore，the effects of control parameter and noise are investigated. The results show that the implementation of this control method is simple and easy. In addition，the controller has strong robustness against weak external noise.
A new inversion simulation method for analyzing experimental data of helium bubble growth in materials
Authors: Zheng Hui  ,   北京应用物理与计算数学研究所，北京  100088
Published: December 2020

Using Monte Carlo method, the helium bubble growth model based on the “migration-coalescence” mechanism is studied in this paper. Based on the simulation, an inversion method of analyzing the experimental data is developed and finally applied to palladium.
Chosen plaintext attack on double random-phase encoding in the Fresnel domain
Authors: Peng Xiang  , Wei Heng-Zheng  , Zhang Peng  ,   (1)天津大学精密测试技术及仪器国家重点实验室，天津 300072; (2)天津大学精密测试技术及仪器国家重点实验室，天津 300072;深圳大学光电子学研究所，教育部光电子器件与系统重点实验室，深圳 518060; (3)中国建设银行总行电子银行部，北京 100032
Published: December 2020

This paper analyzes the security of double random phase encoding in fresnel domain from the viewpoint of cryptoanalysis. We demonstrate the encryption system is vulnerable to chosen-plaintext attack with a prior knowledge of diffraction distance and wavelength. With this attack an opponent can access double random phase keys with the help of the impulse functions as chosen plaintext. The significant feature of proposed attack is that the decryption process is lossless. Numerical simulations show good agreement with theoretical analysis.
A novel high-power semiconductor laser diode with large cavity for high efficiency coupling with the optical fibers
Authors: Yu Hai-Ying  , Cui Bi-Feng  , Chen Yi-Xin  , Zou De-Shu  , Liu Ying  , Shen Gunag-Di  ,   (1)北京工业大学北京光电子技术实验室，北京 100022; (2)山东建筑大学，济南 250101
Published: December 2020

A novel high-power semiconductor laser diode (LD) with very large cavity using multi-active -layer cascaded by tunnel-junction was developed. The window size of the LD was enlarged extremely and less than 20 degree of the lasing beam divergency was obtained，which benefits the coupling between the LD and the optical fiber. Many types of lensed fibers were used to test with the LD and the coupling efficiencies were increased over 30% compared with the conventional LD.
Atomic-scale study of boron-nitrogen co-doping into diamond
Authors: Li Rong-Bin  ,   上海电机学院材料成型工程系，上海  200245
Published: December 2020

The structure and lattice damage induced by four boron (B) atoms and eight nitrogen (N) atoms with the energy of 500 eV co-doped into diamond films at room temperature are investigated by molecular dynamics simulation based on Tersoff empirical potential. The results show that the distribution of most of vacancies is nearer to the surface than the interstitials. Interstitials arrange in diamond in tetrahedral type (T-type) configuration or dumbbell type (D-type) configuration. Percentage of boron atoms and nitrogen atoms located in substitutional positions are found to be around 78%. The B-N bond length is shorter than C-C bond length in diamond by 13%. B-N bonding helps to reduce the lattice distortion in diamond.
Phase separation of Cu-Pb monotectic alloy during rapid solidification
Authors: Xu Jin-Feng  , Dai Fu-Ping  , Wei Bing-Bo  ,   (1)西北工业大学应用物理系,西安 710072; (2)西北工业大学应用物理系,西安 710072;西安理工大学材料学院,西安 710048
Published: December 2020

The rapid solidification and microstructure formation of Cu-Pb monotectic alloy were investigated by melt spinning method. The relationship between liquid separation and physical parameters such as cooling rate and solidification time etc. was analyzed theoretically by coupling the heat transfer equation and Navier-Stokes equation. It is revealed that the rapid cooling of the melt has more remarkable effect on microstructure forming of the monotectic alloys than liquid flow under rapid solidification. The rapid solidification can suppress the liquid separation, which results in the formation of uniform microstructure for various Cu-Pb monotectic alloys. With the rise of cooling rate, the grain size clearly decreases, the microstructure was markedly refined and the microstructural morphology changes from coarse dendrite to uniform and fine equiaxial crystallites. Increasing the cooling rate and shortening solidification time are the essential conditions to suppress liquid phase separation and obtain the uniform monotectic microstructure in gravity field.
Noise in mesoscopic physics
Authors: An Xing-Tao  , Li Yu-Xian  , Liu Jian-Jun  ,   河北师范大学物理科学与信息工程学院, 石家庄 050016
Published: December 2020

We present a review on the noise in mesoscopic physics. The main sources of noise are briefed. The fluctuations in the occupation number give rise to thermal noise, while shot noise is a consequence of the quantization of charge. We introduce the main theory of noise——scattering theory, which has been applied to saddle-shaped semiconductor quantum wires and ferromagnetic/insulator/semiconductor double heterojunctions. The physical significance of the study of noise are pointed out.
Observations on subband electron properties in In0.65Ga0.35As/In0.52Al0.48As MM-HEMT with Si δ-doped on the barriers
Authors: Zhou Wen-Zheng  , Lin Tie  , Shang Li-Yan  , Huang Zhi-Ming  , Zhu Bo  , Cui Li-Jie  , Gao Hong-Ling  , Li Dong-Lin  , Guo Shao-Ling  , Gui Yong-Sheng  , Chu Jun-Hao  ,   (1)中国科学院半导体研究所，北京 100083; (2)中国科学院上海技术物理研究所红外物理国家重点实验室，上海 200083; (3)中国科学院上海技术物理研究所红外物理国家重点实验室，上海 200083;广西大学物理科学与工程技术学院，南宁 530004; (4)中国科学院上海技术物理研究所红外物理国家重点实验室，上海 200083;华东师范大学ECNU-SITP成像信息联合实验室，上海 200062
Published: December 2020

Magneto-transport measurements have been carried out on a Si δ-doped In0.65Ga0.35As/In0.52Al0.48As metamorphic high-electron-mobility transistor with InP substrate in a temperature range between 1.5 and 60K under magnetic field up to 13T. We studied the Shubnikov-de Haas(SdH) effect and the Hall effect for the In0.65Ga0.35As/In0.52Al0.48As single quantum well occupied by two subbands and obtained the electron concentration and energy levels respectively. We solve the Schrdinger-Kohn-Sham equation in conjunction with the Poisson equation self-consistently and obtain the configuration of conduction band, the distribution of carriers concentration, the energy level of every subband and the Fermi energy. The calculational results are well consistent with the results of experiments. Both experimental and calculational results indicate that almost all of the δ-doped electrons transfer into the quantum well in the temperature range between 1.5 and 60K.
Properties of electropolymerized high density polypyrrole films
Authors: Wang Jie  , Xu You-Long  , Chen Xi  , Du Xian-Feng  , Li Xi-Fei  ,   西安交通大学电信学院，西安 710049
Published: December 2020

The high density PPy films (HD-PPy，ρ>1.4g/cm3) doped with p-toluenesulfonate (TOS-) counterions were electropolymerized by a facile approach in H2O and acetonitrile (AN) mixed solvent. The structure and electrochemical properties of the HD-PPy films were measured by X-ray photoelectron spectroscopy (XPS), thermogravimetric (TG) analysis, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The results show that appropriate ratio of AN/H2O (99/1) could be favorable to increase the density of PPy films. Further enhancement of the density could be obtained by using higher current density (such as 10mA/cm2), as it favors the formation of two-dimensional structure. Generally, low temperature of polymerization, Tp (e.g. -20℃), is advantageous to the enhancement of density and conductance of PPy films. But if Tp is too low, it beesmes disadvantageous in case of the high current density of polymerization. The HD-PPy films (1.42g/cm3) were obtained at 0 ℃ with 10mA/cm2 in AN/H2O(99/1) solution. Furthermore, HD-PPy films were characterized not only by high electronic conductivity (～220S/cm) and high thermal stability, but also by low electrochemical activity. It was indicated that the HD-PPy would be not only an excellent electrode material but also a promising corrosion protection material.
Influence of ternary mixed crystal defect layer on the localized interface optical-phonon modes in a finite superlattice
Authors: Wang Xin-Jun  , Wang Ling-Ling  , Huang Wei-Qing  , Tang Li-Ming  , Zou Bing-Suo  , Chen Ke-Qiu  ,   (1)湖南大学应用物理系，长沙  410082; (2)湖南大学应用物理系，长沙  410082;中南林业科技大学理学院，长沙  410004
Published: December 2020

Within the framework of dielectric continuum theory, we study the effect of ternary mixed crystal defect layer on the localized interface optical-phonon modes in a finite superlattice by using a transfer matrix method. In such a finite superlattice, the evolution of all the interface modes can be clearly tracked. Our numerical results show there exist two types of localized modes and their macroscopic electrostatic potentials mostly locate in the vicinity of the defect layer or surface layer, respectively. As the relative widths and nature of the structural cell or the defect layer are altered, the localized characteristics of these modes are significantly influenced. Though the conservation of the total number of localized modes is broken, the conservation of the total number of all interface modes including both the extended modes and localized modes is still kept for every value of the wavevector q‖.
Reservoir neural state reconstruction and chaotic time series prediction
Authors: Han Min  , Shi Zhi-Wei  , Guo Wei  ,   大连理工大学电子与信息工程学院，大连  116023
Published: December 2020

ESN(Echo state network) is a new type of recurrent neural network, which is based on the “reservoir”. ESN has been proved to be significantly efficient to deal with some chaotic time series prediction tasks. This paper makes an analysis of the current iterative prediction method based on “reservoir”, and points out some problems in theory and the obstacles in application. And then, a direct prediction method is proposed, which relates the prediction origin and prediction horizon directly. The direct method does not close the loop in the process of prediction, so there are no such problems as instability and error accumulation. The simulation results show how the reservoir property changes when the loop is closed in the iterative prediction, and then demonstrate the feasibility of the direct prediction method in application to the Mackey-Glass benchmark prediction problem.
Effect of boundary conditions on phonon transmission in a dielectric quantum waveguide
Authors: Tang Li-Ming  , Wang Yan  , Wang Dan  , Wang Ling-Ling  ,   湖南大学应用物理系，长沙  410082
Published: December 2020

We investigate the effect of boundary conditions on the low temperature phonon transport in a quantum waveguide with structural defects by using the scattering-matrix method. A comparison between transmission coefficients is made when Neumann and Dirichlet boundary conditions are applied for acoustic modes, respectively. The result indicates that the behavior of the transmission coefficient versus reduced phonon frequency is qualitatively different for different boundary conditions. The stop-frequency gap and the transmission resonance are observed for certain structural parameters due to mode-mode coupling.
Three-dimensional finite-difference time-domain implementation for anisotropic dispersive medium using recursive convolution method
Authors: Yang Li-Xia  , Ge De-Biao  , Wei Bing  ,   西安电子科技大学物理系,西安 710071
Published: December 2020

The permittivity in the frequency domain is transformed to the time domain, and the complex electric susceptibility dyadic matrix and the complex electric displacement vector in time domain are introduced. The three_dimensional finite_difference time_domain method based on the recursive convolution principle(RC_FDTD) for the electric anisotropic dispersive medium is discussed in detail. To exemplify the availability of the RC-FDTD algorithm, the backscattering RCS of a non-magnetized plasma sphere is computed, and the numerical results are the same as that of shift operator_FDTD method, which shows that the RC-FDTD method is correct and efficient. In addition, the co-polarized and cross-polarized backscattering waves in time domain for a magnetized plasma sphere are obtained by the RC-FDTD algorithm. The results show that when the external magnetic field is implemented, the cross-polarized component appear evidently.
Crystallization of Si3N4 and superhardness effect of ZrN/Si3N4 nano-multilayers
Authors: Zhao Wen-Ji  , Dong Yun-Shan  , Yue Jian-Ling  , Li Ge-Yang  ,   上海交通大学金属基复合材料国家重点实验室,上海  200030
Published: December 2020

The crystallization behavior of Si3N4 modulation layers in the multilayers and its influences on the microstructure and mechanical properties of ZrN/Si3N4 multilayers were studied. ZrN/Si3N4 multilayers with different Si3N4 thickness were synthesized by reactive magnetic sputtering. The microstructure of the multilayers was characterized with X-ray diffraction and high-resolution transmission electron microscopy, and a nanoindentor was introduced to measure their mechanical properties. The results show that when the thickness is less than 0.9 nm, Si3N4, normally amorphous in the deposited state, could form a NaCl-type pseudocrystal structure due to the template effect of ZrN crystal layer. Crystallized Si3N4 layers and ZrN template layers grow epitaxialy into columnar crystals. Correspondingly, the hardness of the films was enhanced, showing a superhardness effect. Further increasing Si3N4 layer thickness, the coherent interfaces of the multilayers were damaged and Si3N4 layers become amorphous, accompanied by the decline in the hardness of the films.
Optical vortex solitons in strongly nonlocal nonlinear media
Authors: Dai Ji-Hui  , Guo Qi  , Shi Xin-Rong  ,   华南师范大学光子信息技术实验室，广州 510631
Published: December 2020

We solved the equations of the Snyder-Mitchell model, which is a model describing the propagation of optical beams in nonlocal nonlinear media with strong nonlocality, in a rotating cylindrical coordinate system, and obtained a self-similar analytical solution of an optical vortex soliton. The result shows that the radial part of the solution is the product of the Whittaker and power function. The beam has a ring-shaped structure rotating around its core.
Analysis of the anechoic properties of viscoelastic coatings with periodically distributed cavities
Authors: Zhao Hong-Gang  , Liu Yao-Zong  , Wen Ji-Hong  , Yu Dian-Long  , Wen Xi-Sen  ,   国防科学技术大学机电工程研究所,长沙 410073
Published: December 2020

Using an exact Mie scattering solution, the scattering and vibration mode of a single air sphere in unbounded rubber are analyzed with reference to the elements of the scattering matrix. Then, using the multiple_scattering method, the anechoic properties of the viscoelastic rubber coating (with a thickness of 8mm) containing a plane of periodically distributed air spheres are investigated under different backing conditions. The results show that the excellent anechoic performance of the coating originates from the dilatational resonance of each air sphere. The anechoic coating can attenuate most incident energy and minimize reflection in the resonance frequency region. Finally, a bi_layer coating (with a thickness of 20mm) is designed for broad_band anechoic material.
The interstitial oxygen atoms and its effects for optical properties of PWO crystals
Authors: Chen Teng  , Liu Ting-Yu  , Zhang Qi-Ren  , Tian Dong-Sheng  , Zhang Xiu-Yan  , Yi Zhi-Jun  ,   上海理工大学理学院，上海  200093
Published: December 2020

The positions of the interstitial oxygen atoms in PWO crystals are numerically simulated by. It was found that the formation energy of isolated point defect is small when oxygen atom exists around the (WO4)2-. Based on the computed results, the total density of states and partial density of states of perfect PWO crystals and PWO crystals with interstitial oxygen atoms were calculated using DV-X α program. It is concluded that interstitial oxygen atoms will combine with oxygen ions of (WO4)2-, forming oxygenic molecule ions which are related to the 350 nm absorption band.
Binding energies of excitons in symmetrical GaAs/Al0.3Ga0.7As double quantum wells
Authors: Zhang Hong  , Liu Lei  , Liu Jian-Jun  ,   河北师范大学物理科学与信息工程学院,石家庄  050016
Published: December 2020

The binding energies of excitons in symmetrical GaAs/Al0.3Ga0.7As double quantum wells are calculated variationally by using a simple wave function within the effective-mass approximation. The variation of the binding energies as functions of the well and barrier width is studied. It is found that, the changing tendency of the binding energies with the well width is similar to that of the single quantum well. However, we found that the maximum value of the binding energy occurs at well size of about 10?. The well size is smaller than that in single quantum wells. The binding energies have a minimum during the increase of the barrier width, which is related to the penetration into the barrier of the wave function.
Exact diagonalization solution and coherent state variational method of the coupling system of carrier and ferromagnetic material
Authors: Huang Shu-Wen  , Liu Tao  , Fan Yun-Xia  , Wang Ke-Lin  ,   (1)西南科学技术大学理学院,  绵阳  621010; (2)西南科学技术大学理学院,  绵阳  621010;中国科学技术大学近代物理系, 合肥  230026
Published: December 2020

The problem of the coupling system of carrier and ferromagnetic material has been transformed into that of the coupling system of carrier and two kinds of Bosons by using Schwinger's oscillator theory of angular momentum. That the existence of bound polaron in ferromagnetic material depends on the existence of impurity potential in this material is solved exactly by diagonalization and the conclusion obtained is in agreement with the general view point of other works. The values of the energy of ground state obtained by the exact solution and coherent state variation method is agree quite well.The qualitative characters of state vector given by both methods are consistent. The results shows that the coherent state variation method is valid and precise enough for this problem. Exact solution method will provide a basis to check the validity of any other approximate methods.
Thermal stability of electrical characteristics of nickel silicide metal gate
Authors: Shan Xiao-Nan  , Huang Ru  , Li Yan  , Cai Yi-Mao  ,   北京大学微电子系，北京 100871
Published: December 2020

The electrical characteristics of NiSi metal gate and their thermal stability were studied. A physical model is proposed to explain the increase in NiSi work function when the forming temperature is higher than 500 ℃. By measuring the sheet resistance of NiSi film prepared at different temperatures, it is shown that NiSi has the lowest resistance when formed at 400 ℃, which is stable from 400 to 600 ℃. The X-ray diffraction measurement for the NiSi samples formed at various temperatures revealed that NiSi phase was the main component at temperatures from 400 to 600 ℃. The capacitors formed by furnace annealing has higher equivalent oxide charge Qox and lower breakdown electric field Ebd, which proves that furnace annealing is unsuitable for NiSi metal gate fabrication due to the long time of thermal processing (400 ℃ for 30 min). The electrical characteristics of NiSi gate metal oxide semiconductor capacitors formed at various rapid thermal annealing(RTA) temperatures were studied. By comparing theC-V curves, Ig-Vg curves and Qox of the capacitors, it was found that when the RTA temperature is higher than 500 ℃, reaction between NiSi and gate oxide will occurr, reducing the quality of the gate dielectric. In conclusion, the suitable forming temperature of NiSi metal gate should be from 400 to 500 ℃. Moreover, the NiSi work function and Qox formed at 400, 450 and 500 ℃ respectively were also determined.
Interface phonons in the active core of a quantum cascade laser
Authors: Xu Gang-Yi  , Li Ai-Zhen  ,   中国科学院上海微系统与信息技术研究所信息功能材料国家重点实验室,上海  200050
Published: December 2020

We consider the propagation of the interface phonons in the active core of a quantum cascade laser. Based on the translation invariance in the interior of the active core, an implicit dispersion relation is derived. Numerical calculations show that the interface phonons in the active core can be classified as bulk phonons and surface phonons. The dispersion curves of bulk phonons form a series of subbands, and their electrostatics potential is distributed in the whole region of the active core, showing the character of Bloch wave. While the dispersion curves of the surface phonons are located in the gap between the subbands of the bulk phonons, and the electrostatic potential is localized near the interface between the active core and the waveguide layer. Our results are helpful to the design of quantum cascade lasers and other intersubband lasers.
Effect of solvent on the performance of poly(2-methoxy-5-(2-ethyl-hexyloxy)-p-phenylene vinylene): N, N′-bis(1-ethylpropyl)-3,4,9,10-perylene bis(tetracarboxyl diimide) solar cells
Authors: Wu Wei-Cai  , Zhou Yin-Hua  , Wen Shan-Peng  , Han Liang  , Tian Wen-Jing  ,   吉林大学超分子结构与材料教育部重点实验室，吉林 130012
Published: December 2020

The effects of different solvents on the morphology of poly(2-methoxy-5-(2-ethyl-hexyloxy)-p-phenylene vinylene) (MEH-PPV): N,N′-bis(1-ethylpropyl)-3,4,9,10-perylene bis(tetracarboxyl diimide) (EP-PTC) blend film and the performance of solar cells based on MEH-PPV: EP-PTC blend film were studied. The results show that the phase separation in the blend film using non-aromatic solvents is of micron (0.5—5 μm) size, which leads to low charge separation efficiency and consequently the low power conversion efficiency of the assembled solar cell; whereas the phase separation in the blend film using aromatic solvents is of nano-size, which increases the interface area of the two phases obviously and consequently increases the ratio of charge separation significantly. The power conversion efficiency of solar cells based on MEH-PPV: EP-PTC blend film using aromatic solvents is improved 30 times of magnitude compared with that of solar cell based on the blend film using non-aromatic solvents.
Fabrication of MgB2 films via multilayer ex-situ annealing
Authors: Yu Zeng-Qiang  , Wu Ke  , Ma Xiao-Bai  , Nie Rui-Juan  , Wang Fu-Ren  ,   北京大学物理学院，人工微结构和介观物理国家重点实验室，北京  100871
Published: December 2020

We fabricated superconducting MgB2 films with Mg/B multilayer precursors followed by ex-situ annealing. Different ways of samples' placement have been tried, and we found that turning over the samples can effectively removed the particles of Mg condensed on the film surface. The Tc of the films was about 35K with a transition width of 0.8K. The surface is quite smooth, having a roughness of 10 nm in an area of 5 μm×5 μm. When the thickness of the film is less than 1000?, the Tc is significantly reduced. With the different configurations of the multilayer precursor, the Tc of a 600?-thick film can be optimized to 32K and the Jc is 2.4×106A/cm2 at 20K.
Study on the role of Nb addition in rapid-quenched NdFeB permanent magnets
Authors: Zhang Ran  , Liu Ying  , Li Jun  , Ma Yi-Long  , Gao Sheng-Ji  , Tu Ming-Jing  ,   四川大学材料科学与工程学院，成都  610064
Published: December 2020

The effect of Nb addition in rapid-quenched (Nd,Dy)11.5Fe82.4-nNbnB6.1 (n=0,0.5,1,1.5,2) permanent magnets on the magnetic properties, temperature characteristics and microstructure has been investigated. It is found that Hcj increases with increasing Nb content and the irreversible loss of magnetic flux decreases. Nb addition results in smaller grains and more homogeneous and regular grain structure. It is considered that Nb addition may enhance exchange coupling pining field and reduce internal stray magnetic field. As a result, the irreversible loss of magnetic flux decreases notably and the magnetic properties at higher temperature are improved.
Study on the localization of the electric dipole sources
Authors: Wu Chong-Qing  , Zhao Shuang  ,   发光与光信息技术教育部重点实验室，北京交通大学理学院光信息科学与技术研究所,北京 100044
Published: December 2020

The research of dipole source localization has great significance in both clinical research and applications. For example, the EEG recording from the scalp is widely used for the localization of sources of electrical activity in the brain. This paper presents a closed formula that describes the electric field of dipoles at arbitrary position, which is a linear transformer called the transfer matrix. The expression of transfer matrix and its many useful characteristics are given, which can be used for the analysis of the electrical fields of dipoles.This paper also presents the closed formula for determining the location and magnitude of single dipole or multi-dipoles according to its electrical field distribution. A calculation result for a single dipole shows that the dipole will be located at the midpoint of a line segment if there are equivalent fields at its two ends.
Effect of external electric field excitation on methyl vinyl siloxane
Authors: Xu Guo-Liang  , Xiao Xiao-Hong  , Geng Zhen-Duo  , Liu Yu-Fang  , Zhu Zheng-He  ,   (1)河南师范大学物理与信息工程学院,新乡 453007; (2)四川大学原子与分子物理研究所,成都 610065
Published: December 2020

The present paper is devoted to the calculation of transition wavelengths, oscillator strength f, Einstein An0 and B0n coefficients of methyl vinyl siloxane from ground state Cs(X1A′) to the first ten different excited states by employing density functional theory and single substitute configuration interaction approach with basis sets 6-311++G**. At the same time, the excited states of methyl vinyl siloxane under different external electric fields are investigated. It is shown that the HOMO-LUMO gaps become smaller, and the excitation energies of the first ten excited states of methyl vinyl siloxane decrease sharply as the external electric field intensity become strong. The conclusion can be drawn that the transition between the ground state X1A′ and the excited state of methyl vinyl siloxane is easy to bring about.
Theory of array-grating compressor based on in-pair compensation of errors
Authors: Zuo Yan-Lei  , Wei Xiao-Feng  , Zhu Qi-Hua  , Liu Hong-Jie  , Wang Xiao  , Huang Zheng  , Guo Yi  , Ying Chun-Tong  ,   (1)清华大学工程物理系,北京 100084; (2)中国工程物理研究院,绵阳 621900; (3)中国工程物理研究院,绵阳 621900;清华大学工程物理系,北京 100084
Published: December 2020

In terms of Fourier optics, a single-pass tiled-grating compressor based on in-pair compensation is studied and the amplitude expression of the output pulse from the compressor in the far-field is obtained, which disclose that effect of the group delay, the pulse front tilting and the residual chirping on the pulse-width in the far field. Numerical simulation shows that the pulse in the far field is broadened with increasing spectral width. For a typical single-pass tiled-grating compressor, the tolerance of each error is obtained and the allowed spectral width is obtained when all errors are considered.
Theoretical and experimental study of grating tiling
Authors: Zuo Yan-Lei  , Wei Xiao-Feng  , Zhu Qi-Hua  , Liu Hong-Jie  , Wang Xiao  , Huang Zheng  , Guo Yi  , Ying Chun-Tong  ,   (1)清华大学工程物理系,北京 100084; (2)中国工程物理研究院,绵阳 621900; (3)中国工程物理研究院,绵阳 621900;清华大学工程物理系,北京 100084
Published: December 2020

A detailed scheme by which the status of tiled gratings can be inspected in a real-time way is put forward. The He-Ne laser is shown to be inappropriate for the grating-tiling experiment where 1740/mm grating is used. A method is proposed by which the wavelength can be selected for the real-time measurement, so that the impact of all sorts of errors of the tiled gratings on the main beam(1053nm) and the beam for measurement is completely identical, which has been demonstrated by experiment.
Diagnostics on DD fuel area density for indirect drive on Shenguang Ⅱ
Authors: Cao Zhu-Rong  , Jiang Shao-En  , Chen Jia-Bin  , Miao Wen-Yong  , Zhou Wei-Min  , Chen Ming  , Gu Yu-Qiu  , Ding Yong-Kun  ,   中国工程物理研究院激光聚变研究中心，高温高密度等离子体物理国家重点实验室，绵阳 621900
Published: December 2020

Area density is a an important parameter for measuring compression in inertial confinement fusion experiment. Using the MULTI code, physical parameters of fuel plasma are simulated at time of maximum suppression in indirectly driven implosion experiment at Shenguang Ⅱ. Secondary proton energy range in CR-39 is calculated. The average area density 〈ρR〉 of fusion fuel is obtained by measuring secondary protons from D2-filled fuel in the back of CR-39 for the first time. The result shows that CR-39 can be used to measure secondary proton yields of Shenguang Ⅱ. Secondary fusion reaction is affected largely by the suppression state in indirect drive.