bluuebunny/crossref_metadata_2025 huggingface dataset:
The optical and nonlinear optical properties of Au:TiO2 and Au:Al2O3 composite films
Authors: Zhu Bao-Hua  , Wang Fang-Fang  , Zhang Kun  , Ma Guo-Hong  , Gu Yu-Zong  , Guo Li-Jun  , Qian Shi-Xiong  ,   (1)复旦大学物理系，上海  200433; (2)河南大学微系统物理研究所，光学与光电子技术研究所，开封  475001; (3)上海大学理学院，上海  200444
Published: December 2020

On the basis of measurement and theoretical analysis，optical and nonlinear optical properties of the Au：TiO2 and Au：Al2O3 composite films with different Au nanoparticle size and different substrates were investigated. The relationship between the Au nanoparticle size and substrates and the surface plasmon resonance (SPR) of Au composite films were characterized by UV-VIS-NIR spectroscopy，and the dependence of third-order nonlinear susceptibility of the composite films on Au nanoparticle size and substrates was investigated by picosecond Z-scan technique with different exciting wavelengths (532nm and 1064nm). The analysis of optical properties of these films was carried out using the theories of surface plasmon resonance and localized field enhancement，respectively. The experimental and theoretical results revealed the dependence of third-order nonlinear susceptibilities χ(3) on Au nanoparticle size and substrates. For Au nanoparticle of size around 35nm embedded in TiO2 substrate with larger permittivity and the exciting wavelength at 532nm close to the surface plasmon resonance (618nm—632nm)，the third-order nonlinear susceptibility χ(3) showed a maximum value of 25×10-9esu.
Generalized projective synchronization and tracking control of complex Dynamos systems
Authors: Min Fu-Hong  , Wang Zhi-Quan  ,   (1)南京理工大学自动化系，南京  210094; (2)南京理工大学自动化系，南京  210094；南京师范大学电气与自动化工程学院，南京  210042
Published: December 2020

Based on the system stability theory，a new tracking control method is proposed to acquire asymptotically generalized projective synchronization of full states of a complex dynamos system and arbitrary trajectories. It also allows us to drive a complex dynamos system to arbitrary periodic orbits or fixed point. The technique can direct the scaling factor to a desired value. Sinusoidal waves，chaotic systems，hyper-chaotic systems and fixed points are taken as examples respectively. Numerical simulation results are presented to demonstrate the effectiveness of the proposed method.
The effect of infrared laser-induced micro/nano photothermal expansion and the novel method of photothermal actuation
Authors: Zhang Dong-Xian  , Liu Chao  , Zhang Hai-Jun  ,   浙江大学现代光学仪器国家重点实验室，杭州  310027
Published: December 2020

This paper presents a novel asymmetric microactuator based on photo-thermal expansion. It has an asymmetric structure consisting of two thin expansion arms with different widths. When a beam of infrared laser irradiates the arms，the different increases in temperature and photo-thermal expansion controlled by the different rates of specific surface area causes a magnified lateral deflection. In the paper，the thermodynamic model is introduced，and the computing formula of lateral deflection is given. A prototype microactuator of 750μm length has been manufactured by using the excimer laser micromaching system Optec Promaster with an infrared laser diode (998nm) as the external power source to activate the microactuator. Then we carried out feasibility experiments by using a monitored control system made by our laboratory，and measured the relationship between the lateral deflection and laser power. The experiment results demonstrate that the deflection of the microactuator reached 258μm at 16mW infrared laser power. The photo-thermal microactuator has the advantages of simple structure，adjustable deflection，no electromagnetic interference，easy integrating and remote controlling. It will be quite useful for applications in the fields of micro/nano-technology and micro-electro-mechanical systems (MEMS).
Theoretical study of native point defects on anatase TiO2 (101) surface
Authors: Ma Xin-Guo  , Jiang Jian-Jun  , Liang Pei  ,   华中科技大学电子科学与技术系，武汉  430074
Published: December 2020

First-principles plane-wave pseudopotential calculations were performed to study the energetics and the geometical structures of intrinsic vacancies and interstitials on the anatase TiO2 (101) crystal surface. Firstly，we analyzed the effects of point defects on the geometrical structures. For the O vacancy，all the nearest-neighbor Ti atoms move away from the vacancy toward the other O neighborhood. As Ti1 or Ti2 is missing here，O1 atom spontaneously and strongly binds with nearest-neighbor O on the lattice site to form an O2 molecule. The results also show that interstitial Tii2 affects little host lattice and the interstitial Oi would spontaneously bind to lattice oxygen. By investigating the calculated defect formation energies，we found that under the O-rich condition，the VTi1 and Oi formation are favorable，however，under the Ti-rich condition，although the point defects of Tii2 and VO1 easily appear，the formation energy of the Tii2 is lower than that of the VO1. Finally，to determine the relative stability of the point defects，the formation enthalpies of several point defects were considered.
Dependence of growth and property of YBa2Cu3O7-x coated conductors on the thickness of CeO2 buffer layer
Authors: Li Mei-Ya  , Wang Jing  , Liu Jun  , Yu Ben-Fang  , Guo Dong-Yun  , Zhao Xing-Zhong  ,   (1)武汉大学物理科学与技术学院，武汉  430072; (2)武汉大学物理科学与技术学院，武汉  430072；武汉大学教育部声光材料与器件重点实验室，武汉  430072
Published: December 2020

Biaxially textured MgO templates were grown on un-textured metal substrates by inclined-substrate-deposition and YBa2Cu3O7-x films were epitaxially grown on these substrates by pulsed laser deposition. Yttria-stablized-zirconia and CeO2 were deposited in turn as buffer layers prior to YBa2Cu3O7-x growth. The biaxial alignment features of the films were examined by X-ray diffraction 2θ-scan，pole-figure，-scan and rocking curve of Ω angles. The Raman spectroscopy，scanning electron microscopy and atomic force microscopy were used to characterize the orientation order，morphology and surface roughness of the YBa2Cu3O7-x films，respectively. The influence of the thickness of CeO2 on the properties of the YBa2Cu3O7-x films were investigated and the singnificant and unique dependence of the properties of YBa2Cu3O7-x films on the thickness of CeO2 were revealed. The possible mechanisms for this dependence were discussed.
Study of friction between hydrocarboxylic acid Langmuir-Blodgett films and its mechanism using molecular dynamics simulation
Authors: Zhang Zhao-Hui  , Han Kui  , Li Hai-Peng  , Tang Gang  , Wu Yu-Xi  , Wang Hong-Tao  , Bai Lei  ,   中国矿业大学理学院，徐州  221008
Published: December 2020

Molecular dynamics simulation has been used to study the friction and structure mechanism of Langmuir-Blodgett films of hydrocarboxylic acid (C15H31COOH) deposited on the SiO2 substrates at different sliding velocities. The results show that, for a certain monolayer, the shear pressure between the monolayers increases when the sliding speed is below 60m/s and decreases when the sliding speed exceeds 60m/s. The molecular tilt angle decreases as the velocity increases. The molecular clusters formed in the monolayers by the hydrogen-bond caused the long shear periods, but there is no hydrogen-bond between the monolayers.
Electronic Raman scattering and the second-order Raman spectra of the n-type SiC
Authors: Han Ru  , Yang Yin-Tang  , Chai Chang-Chun  ,   西安电子科技大学微电子学院，宽禁带半导体材料与器件教育部重点实验室, 西安  710071
Published: December 2020

The Raman scattering spectra of the nitrogen doped n-SiC is studied. The theoretical line shape analysis indicates that, compared with 4H-SiC, the shift of the LO phonon-plasma coupled mode in 6H-SiC with free carrier concentration is smaller. From the electronic Raman spectra, which were obtained with laser excitation at 5145nm, there are four spectral lines in 6H-SiC and two lines in 4H-SiC, which correspond to the 1s(A1) to 1s(E) valley orbit transitions at the inequivalent k site. The explanation of the high-frequency signals of 6303 and 635 cm-1 is that they are velated with transitions at active deep level of defect. Finally, the second-order Raman features of 6H- and 4H-SiC are identified using the selection rules for second-order scattering in wurtzite structure.
Optically transparent band-pass frequency selective surface
Authors: Li Xiao-Qiu  , Feng Xiao-Guo  , Gao Jin-Song  ,   (1)中国科学院长春光学精密机械与物理研究所,长春  130033; (2)中国科学院长春光学精密机械与物理研究所,长春  130033；中国科学院研究生院，北京  100049
Published: December 2020

Effects of the conductivity of transparent conductive film on the optically transparent band-pass frequency selective surface (FSS) are investigated by using Galerkin's method in the spectral domain. According to the results of the calculation and measurement, it is found that the conductivity of transparent conductive film mainly affects the transmission coefficient at the resonance frequency in radar wave band. The optically transparent band-pass frequency selective surface can transmit optical band and reflect radar wave band, however, it can also selectively transmit the radar wave.
Negative charging process of a grounded insulating thin film under low-energy electron beam irradiation
Authors: Li Wei-Qin  , Zhang Hai-Bo  ,   西安交通大学电子科学与技术系教育部电子物理与器件重点实验室,西安  710049
Published: December 2020

The negative charging process and its mechanism caused by low-energy electron beam (e-beam) irradiation have been clarified for an insulating thin film with a grounded conductive substrate. Numerical simulation is performed by considering both electron scattering and electron transport, in combination with the Monte Carlo method and the finite difference method. The internal space charge, leakage current, surface potential and their time-evolution under e-beam irradiation are eventually obtained under different e-beam conditions and for different SiO2 film parameters. Results show that owing to the drift produced by mobility and diffusion, incident electrons can go beyond the conventional scattering region and arrive at the substrate after a certain transit time, forming negative space charge and leakage current. The transient negative charging process tends to equilibrium as the leakage current increases. In the equilibrium state, the leakage current increases with the energy and intensity of the e-beam. Meanwhile, the amount of net negative charge and the absolute value of surface potential increase with the film thickness, decrease with the increase of electron mobility, and both exhibit a maximum value with variation of the e-beam energy.
Analysis of positron annihilation in carbon allotropes
Authors: Chen Xiang-Lei  , Kong Wei  , Weng Hui-Min  , Ye Bang-Jiao  ,   中国科学技术大学近代物理系，合肥  230026
Published: December 2020

Superposed-neutral-atom model and the finite-difference method (SNA-FD) are used to calculate the positron annihilation lifetime in graphite, diamond and C60 We find that in graphite with laminar structure，the main place where the positron exists and annihilation takes place is the space between graphite layers. Positron lifetime of graphite is calculated to be 208ps, which agrees with the published experimental result. In diamond, the main place where positron exists and annihilation takes places is the space between carbon atoms. Positron lifetime of diamond is calculated to be 1150ps, which agrees with the published experimental result. In C60 with a fcc structure, the main area where positron exits is the space near the spherical molecule shell of C60 and the space between molecules. The main area where positron annihilation takes place is the space between molecules. Positron lifetime of C60 is calculated to be 352ps, which falls in the range of positron lifetime of C60 published in literature.
Study of one-dimensional spatial distribution of the plasma luminous radicals during depositing silicon films
Authors: Chen Fei  , Zhang Xiao-Dan  , Zhao Ying  , Wei Chang-Chun  , Sun Jian  ,   南开大学光电子薄膜器件与技术研究所，天津  300071
Published: December 2020

One-dimensional spatial distribution of the plasma luminous radicals during depositing silicon films and its online monitoring were studied using optical emission spectroscopy. The results indicated that there existed an evident luminous zone in the middle of the plasma and a dark zone near the two electrodes. The intensity of SiH* and Hα* peak increased with the increase of silane concentration, power, and the incorporation of borane. Crystalline volume fraction of thin films decreased with the increase of borane flow rate, but the ratio of I［Hα*］/I［SiH*］ was also increased. The ratio of I［Hα*］/I［SiH*］ varied in different ways at different positions with the variation of silane concentration. However, an unigue variation of the ratio all over the plasma is observed with the variation of the discharge power or the borane flow rate.
Effects of LA phonon on pure dephasing for exciton qubit
Authors: Liu Yun-Fei  , Xiao Jing-Lin  ,   河北科技师范学院数理系，秦皇岛  066004；内蒙古民族大学物理与电子信息学院，通辽  028043
Published: December 2020

In a parabolic quantum dot (QD), the exciton vacuum state and the exciton ground state may be employed as a two-level quantum system——a qubit. The pure dephaseing due to deformation potential exciton-bulk longitudinal acoustic phonon (LAP) interaction for the exciton qubit is investigated by using the reduce density matrix. The dependence of dephasing factor on time and the confinement length of the QD and temperature is calculated. It is shown that the pure dephasing factor increases quickly with increasing time when time is smaller than 2.5ps, and the dephasing time is of the order of ps. Even at absolute zero temperature, exciton-LAP interaction still causes excitonic dephasing. The pure dephasing factor increases with increasing temperature quickly when temperature is higher than 3K. At the same time, it is found that the confinement length of the QD has important effects on pure dephasing of qubit, the smaller the quantum size, the faster the pure dephasing is. The results show that using appropriate QD size at low temperature and using ultra-fast laser technology can effectively suppress pure dephasing due to exciton-LAP interaction.
Quantum statistical entropy of axisymmetric black hole
Authors: Zhang Li-Chun  , Hu Shuang-Qi  , Li Huai-Fan  , Zhao Ren  ,   (1)山西大同大学物理系,大同  037009; (2)山西大同大学物理系,大同  037009；中北大学环境与安全工程系，太原  030051; (3)中北大学环境与安全工程系，太原  030051
Published: December 2020

Using the quantum statistical method, the difficulty of solving wave equation on the background of the black hole is avoided. We directly solve the partition functions of bosonic field and fermionic field on the background of the axisymmetric Kerr black hole through using the new equation of state density motivated by the generalized uncertainty relation in the quantum gravity theory. Then the entropy of the bosonic field and fermionic field near the horizon of the black hole are calculated. In our results the divergence appearing in the brick wall model is removed, as well as without using the small mass approximation. The series expression of the statistical entropy of the black hole is convergent. Therefore, it gives a better understanding of the black hole statistical entropy in non-spherical symmetry spacetimes.
Studies on the construction method of a family of multi-scroll chaotic systems
Authors: Chen Long  , Peng Hai-Jun  , Wang De-Shi  ,   海军工程大学兵器工程系,武汉  430033
Published: December 2020

A method for constructing multi-scroll chaotic systems based on shift transformation is presented. Firstly a proper unstable linear system is selected, and the phase space is divided into several parts by a series of parallel interfaces. Then shift transformations of the linear system are implemented so that each space region is dominated by the corresponding new system. Finally the whole system is obtained using a proper nonlinear function based on signum functions. According to this method new multi-scroll chaotic systems with arbitrary odd number scrolls can be constructed, furthermore, some existing chaotic systems can also be modified into multi-scroll systems. Numerical simulations verify the feasibility of the proposed method.
The complexity analysis of TD-ERCS discrete chaotic pseudo-random sequences
Authors: Sun Ke-Hui  , Tan Guo-Qiang  , Sheng Li-Yuan  ,   中南大学物理科学与技术学院，长沙  410083
Published: December 2020

By observing the phase diagram and using the behavior complexity algorithm, the complexity of chaotic pseudo-random sequences generated by the new TD-ERCS discrete chaotic system is analyzed in detail, and the rules of complexity variety are investigated. Based on the Kolmogorov complexity, from one-dimensional time series to multidimensional phase space restructure, the complexity values of TD-ERCS discrete chaotic pseudo-sequences are calculated by using the Limpel-Ziv algorithm, ApEn algorithm and PE algorithm, respectively. The results show that the behavior complexity of TD-ERCS system is high, and the complexity value changes a little with the change of the parameters of TD-ERCS system. TD-ERCS system is a discrete chaotic system with the steady complexity, and the pseudo-random sequences generated by TD-ERCS are suitable for use in information encryption and spread spectrum communications.
Research on the dynamic modeling based on genetic wavelet neural network for the robot wrist force sensor
Authors: Yu A-Long  ,   淮阴师范学院电子与电气工程系,淮安  223300
Published: December 2020

A kind of new dynamic modeling method is presented based on improved genetic algorithm (IGA) and wavelet neural networks (WNN) and the algorithm is applied to a new type of robot wrist force sensor. The dynamic model of the wrist force sensor is set up according to data of the dynamic calibration, where the structure and parameters of wavelet neural networks of the dynamic model are optimized by genetic algorithm. The results show that the proposed method can overcome the shortcoming of easy convergence to the local minimum points of BP algorithm, and the network complexity, the convergence and the generalization ability are well compromised and the speed and precision of modeling are increased.
Experimental and theoretical study of the length-dependent thermal conductivity of individual single-walled carbon nanotubes
Authors: Wang Zhao-Liang  , Liang Jin-Guo  , Tang Da-Wei  , Y. T. Zhu  ,   (1)Los Alamos National Laboratory,Los Alamos,New Mexico  87545,USA; (2)中国科学院工程热物理研究所，北京  100080; (3)中国石油大学(华东)储建学院，东营  257061
Published: December 2020

We report measurements on the length-dependent thermal conductivity of individual single-walled carbon nanotubes (SWNTs) on a substrate using a four-pad 3ω method with the consideration of heat loss between the sample and substrate. An increase in thermal conductivity with length (0.5—7μm) was observed at room temperature. The length-dependence of thermal conductivity was theoretically predicted by the modified WV model with consideration of second order-3-phonon process. The predicted phonon mean free path is about 175nm. Both the measurement and the prediction show the scale effect of the length on the thermal conductivity of SWNTs.
Effect of uniaxial stress field on determination of equation of state in diamond anvil cell
Authors: Wang Jiang-Hua  , He Duan-Wei  ,   四川大学原子与分子物理研究所，成都  610065
Published: December 2020

Samples in a gasketed diamond anvil cell (DAC) are usually subjected to a uniaxial stress at high pressure due to the geometric structure of the DAC, namely a maximum stress along the cell loading axis and a minimum stress in the radial direction.Using conventional DAC in situ high pressure X-ray diffraction method， the measured compression curves often lie above the hydrostatic compression curves because of the effect of uniaxial stress field.Using the technique of DAC radial X-ray diffraction and the lattice strain theory, through the recent experiments with W, diamond and B6O samples，we discussed how the unixalxial stress filed, sample strength, and the sample difference between the sample material and pressure standard material affect the determination of equation of state.
The application of algebraic reconstruction techniques in X-ray refraction contrast CT
Authors: Zhang Kai  , Zhu Pei-Ping  , Huang Wan-Xia  , Yuan Qing-Xi  , Liu Li  , Yuan Bin  , Wang Jun-Yue  , Shu Hang  , Chen Bo  , Liu Yi-Jin  , Li En-Rong  , Liu Xiao-Song  , Wu Zi-Yu  ,   (1)郑州大学物理工程学院，郑州  450052; (2)郑州大学物理工程学院，郑州  450052；中国科学院高能物理研究所，北京  100049; (3)中国科学院高能物理研究所，北京  100049; (4)中国科学院高能物理研究所，北京  100049；中国科学技术大学国家同步辐射实验室，合肥  230026; (5)中国科学院高能物理研究所，北京  100049；中国科学技术大学国家同步辐射实验室，合肥  230026；中国科学院大科学装置理论物理研究中心，北京  100049
Published: December 2020

X-ray refraction contrast CT is the computer tomography based on phase contrast. When the biological samples are taken from organs or tissues，X-ray refraction contrast CT provides more internal subtle details compared with conventional absorption CT images and it is considered a novel and very promising imaging technique. The iterative and analytical algorithms are the two main strategies in computer tomography. In the field of X-ray refraction contrast CT several analytical algorithms have been reported in the past. However the algorithm using iterative method have not been proposed. In this study，we tested the application of iterative algorithm in X-ray refraction contrast CT image reconstruction，investigated the influence of the order in which data are accessed in algebraic reconstruction techniques，and satisfactory CT images were obtained. Our data demonstrated that when biological samples are imaged or the complete projective data are not available，our iterative algorithm showed significant advantage over the analytical algorithms. It effectively reduces the number of the projection data，exposure time，as well as the radiation damage to the biology samples.
Measurement of branching ratios of Pd I
Authors: Han Li-Li  , Dai Zhen-Wen  , Wang Yun-Peng  , Jiang Zhan-Kui  ,   吉林大学物理学院，相干光与原子分子光谱教育部重点实验室，长春  130023
Published: December 2020

With a hollow cathode lamp and!a highly-resolution grating monochromator，the emission spectrum of 7 energy levels from the even-parity configurations 4d96s and 4d95d of palladium (Pd) have been measured. Branching ratios of 15 lines produced by the transitions from these levels to 4d95p levels were derived. The majority of our results can provide corrections for the related atomic parameters of Pd atom in the literature.
The rigorous theory of nonparaxial vectorial Gaussian beams diffracted at a slit
Authors: Li Jian-Long  , Lü Bai-Da  ,   四川大学激光物理与化学研究所，成都  610064
Published: December 2020

The rigorous electro-magnetic diffraction theory of nonparaxial vectorial beam is proposed and illustrated by the diffraction of nonparaxial vectorial Gaussian beam diffracted at a slit. A numerical comparison with the analytical expressions based on the vectorial Rayleigh-Sommerfeld diffractiion integrals is given to show the consistency between them. A futher extension of the theory is briefly discussed.
Measurement of entangled state of light with non-degenerate frequency utilizing non-balanced fiber Mach-Zehnder interferometer
Authors: Shang Ya-Na  , Wang Dong  , Yan Zhi-Hui  , Wang Wen-Zhe  , Jia Xiao-Jun  , Peng Kun-Chi  ,   山西大学光电研究所，量子光学与光量子器件国家重点实验室，太原  030006
Published: December 2020

The dependence of the quantum correlation of twin beams generated from a non-degenerate optical parametric oscillator on the analysis frequency was theoretically studied with semi-classical method. It was pointed out that the quantum entanglement is higher at lower analysis frequency. By means of a pair of unbalanced fiber Mach-Zehnder interferometers，the correlation noise spectrum of the intensity-difference and the phase-sum of twin beams with non-degenerate frequencies and total power of 20mW were experimentally measured，which were 3.1 and 1.3dB below the corresponding shot noise limit at 2MHz，respectively. The experimental results are in agreement with the theoretical predictions.
Determination of air ionization threshold with femtosecond laser pulses
Authors: Wang Xiao-Lei  , Zhang Nan  , Zhao You-Bo  , Li Zhi-Lei  , Zhai Hong-Chen  , Zhu Xiao-Nong  ,   南开大学现代光学研究所,天津  300071；光电信息技术科学教育部重点实验室,天津  300071
Published: December 2020

The intensity thresholds of air ionization induced by 800nm ultrashort laser pulses are investigated for laser pulse durations from 50fs to 22ps. The intensity threshold was determined by measuring the fluorescence energy of the stimulated air ionization plasma. It is shown that as the pulse duration increases from 50fs to 22ps, the threshold intensity of air ionization decreases from 8.7×1014 to 2.7×1013W/cm2 and undergoes the transition from rapid decrease to slow decrease. For pulse duration shorter than 1ps, the theoretical calculation was done based on the multiphoton ionization and for pulse duration longer than 1ps, the calculation was done based on the impact ionization initiated by the multiphoton ionization. For both above cases the calculated results are in good agreement with the experiment.
Experimental study of bright photovoltaic solitons in lithium niobate crystal
Authors: Kang Yi-Fan  , Lu Ke-Qing  , Hu Man-Li  , Kang Xiao-Hui  , Zhang Mei-Zhi  , Wang Chao  , Zhou Li-Bin  , Chen Xing  ,   (1)西安电子科技大学计算机学院，西安  710071; (2)西安交通大学电子科学与技术系,西安  710049; (3)西北大学物理系,西安  710069; (4)西北大学物理系,西安  710069；中国科学院西安光学精密机械研究所，瞬态光学与光子技术国家重点实验室，西安  710119; (5)中国科学院西安光学精密机械研究所，瞬态光学与光子技术国家重点实验室，西安  710119
Published: December 2020

The effect of background beam with different Glass constant on the relative spatial refractive perturbation in photovoltaic crystal was discussed, in which was introduced the concrete conditions for the formation of bright or dark photovoltaic spatial solitons in crystals with negative refractivity change. Based on the results, for what is to our knowledge the first time, the bright photovoltaic solitons was experimentally observed in LiNbO3:Fe by use of e-ray signal of 532nm and o-ray background illumination of 488nm.
The propagation properties of symmetrical hyperbolic secant beams in weakly nonlocal nonlinear bulk media
Authors: Xiao Yi  , Guo Qi  , Yang Xiang-Bo  , Lan Sheng  ,   (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  510631; (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  510631；暨南大学光电工程系，广州  510632; (3)华南师范大学激光生命科学研究所，广州  510631
Published: December 2020

The propagation of (2+1)D paraxial symmetrical hyperbolic secant beams in weakly nonlocal nonlinear media is studied by variational approach. A series of differential equations which describe the evolutions of the width, the phase, the phase front curvature, and the amplitude of the beam are obtained. The critical power for a beam propagating as a spatial optical soliton in weakly nonlocal nonlinear media is also obtained. A quantitative depiction of the steadying effect of nonlocality on the propagation of a beam is obtained through the steadiness analyse, which provides a self-consistent explanation of the transition from unsteady local kerr solitons to steady weakly nonlocal solitons. The results of numerical method agree with that of variational calculations, implying that hyperbolic secant function is a good approximation to a (2+1)D weakly nonlocal spatial optical soliton.
The mode characteristics of a symmetrical slab waveguide with single-negative-material cladding
Authors: Chen Xian-Feng  , Shen Xiao-Ming  , Jiang Mei-Ping  , Jin Yi  ,   江苏工业学院信息科学系，常州  213016
Published: December 2020

The propagating characteristics of a symmetrical three-layer slab waveguide with mu-negative (MNG) media are studied in detail. It is found the MNG waveguide can propagate not only quick waves but also slow waves of TE0 and TE1 modes. The properties of this guided mode are different from those of the left-handed waveguide and the conventional waveguide. In MNG slab waveguide, the region of effective refractive index of the guided mode is wider than those of the other two. In addition, the TE0 fundamental guided mode does not exist at all, while the higher-order TE guided modes and all TM guided modes do exist. However the surface wave of TE0 and TE1 modes can emerge under a certain condition. The propagation constant of higher-order TE mode is greater than that of the TM mode of the same order. Two TE modes of the same order can coexist in the MNG, which is closely related to the structural parameters. The energy fluxes of two TE modes are oppositely directed inside and outside the inner layer, therefore the total energy flux can be negative.
Measurement and numerical simulation of the bandgap in hollow-core photonic crystal fibers
Authors: Mi Yan  , Hou Lan-Tian  , Zhou Gui-Yao  , Wang Kang  , Chen Chao  , Gao Fei  , Liu Bo-Wen  , Hu Ming-Lie  ,   (1)天津大学精密仪器与光电工程学院超快激光研究室,天津  300072; (2)燕山大学亚稳材料制备技术与科学国家重点实验室，秦皇岛  066004
Published: December 2020

The full-vector plane-wave method was used to calculate the bandgaps of the photonic crystal fiber with triangular structure. The transmission spectrum of the hollow-core photonic crystal fiber fabricated by Yanshan University was measured, and we obtained the relation between the transmission intensity and the wavelength in visible region. In the subsequent experiment, the mode field patterns were observed. The theoretical simulation is well consistent with the experimental result.
Effect of dielectric charging on gating light modulator
Authors: Sun Ji-Yong  , Huang Shang-Lian  , Zhang Jie  , Zhang Zhi-Hai  ,   重庆大学光电工程学院,光电技术及系统教育部重点实验室,重庆  400044
Published: December 2020

Electric field distribution of the light modulator affected by the dioxide dielectric charging is deduced with Gauss law. Electrostatic force formula of the movable grating under such condition is obtained. Charging and discharging mechanisms of the dielectric have been analyzed. The relationship between movable grating's displacement and the dielectric charge is obtained. The results show that the grating will bounce back and then be pulled down when it is actuated by low frequency voltage. When the actuating voltage period is far shorter than the charging time constant, variation of the modulator's output light intensity will be increasingly small until the modulator is disabled thoroughly when the field produced by the storage charges is half that of the actuating electric field. Experiment was carried out to test the theoretical analysis and the results agree well. Finally, a method is proposed to eliminate the storage charge, and its feasibility is proved by the experiment.
Temperature coefficient of collision factor and mol collision factor
Authors: Lu Yi-Gang  ,   华南理工大学物理科学与技术学院，广州  510640
Published: December 2020

碰撞因子， 碰撞因子温度系数， 克分子碰撞因子， 声速温度系数
Forward Mie scattering method applied to the measurement of the R(t) curve of single bubble sonoluminescence
Authors: Ke Wei-Na  , Chen Qian  , Qian Meng-Lu  ,   同济大学声学研究所,上海  200092
Published: December 2020

In single bubble sonoluminescence (SBSL), the forward Mie scattering signal of the bubble, which is waved due to the interference between the scattered light components, provides a scale for measuring the change of the bubble radius. The unit of the scale is decided by the scattered angle θ, the optical wavelength λ, and the relative refraction index n of the fluid; and the scale marks are the peaks and valleys of forward scattered light, which correspond to specific radius values. The forward Mie scattering method has been applied in measurement of the R(t) curve, especially the maximum radius value Rmax, and further in the fit of the equilibrium radius R0 of bubble in SBSL, and is proved to be a feasible and convenient technique in the study of the bubble dynamics in SBSL.
Research on electromagnetic wave absorbing properties of nano tetraleg ZnO
Authors: Cao Jia-Wei  , Huang Yun-Hua  , Zhang Yue  , Liao Qing-Liang  , Deng Zhan-Qiang  ,   (1)北京科技大学材料物理与化学系,北京  100083; (2)北京科技大学材料物理与化学系,北京  100083；北京科技大学新金属国家重点实验室,北京  100083
Published: December 2020

Wave-absorbing coating samples were fabricated with nano tetraleg ZnO as the absorbent and epoxy resin as the binder. The influence of the content of nano tetrapleg ZnO in the absorbing coatings and the thickness of the coatings on wave-absorbing property was investigated. The results showed that excellent absorption was observed in the wave band from 15GHz to 18GHz when the coating thickness was 15mm. When the coating thickness increased to 35mm, the wave-absorbing property of the samples was improved significantly, especially in the wave band from 6GHz to 11GHz. The frequency width reached 136GHz (44—18GHz) when the reflection value of the samples was below -5dB, its wave-absorbing property has obviously improved compared with that of the micrometer sized ZnO. Finally, the wave-absorbing mechanism of nano tetraleg ZnO was discussed. Such coatings are of great values in applications involving electromagnetic wave shielding.
The effects of the grafted hydroxyl on the elastic properties of single-walled carbon nanotubes
Authors: Yuan Jian-Hui  , Yuan Xiao-Bo  ,   (1)长沙理工大学电气与信息工程学院，长沙  410076; (2)长沙理工大学物理与电子科学学院,长沙  410076
Published: December 2020

The molecular dynamics method was used to investigate the elastic properties of armchair and zigzag single-walled carbon nanotubes grafted by hydroxyl on their ports. The results showed that the Young's moduli of ungrafted armchair (5, 5)，(10,10) and zigzag (9, 0) , (18,0) single-walled carbon nanotubes were 948，901 and 804, 860GPa, respectively. When the single-walled carbon nanotubes were grafted by 2 to 8 hydroxyl functional groups, the Young's modulus of the zigzag single-walled carbon nanotubes was little changed, while the Young's modulus of the armchair single-walled nanotubes first decreased significantly due to the grafting, then increased appreciably to some steady value with increasing of the grafts after having been grafted to certain numbers. The reasons were analyzed in terms of the isoline structure of deformation electron density, C—C bond-length and the system binding energy variation of the carbon nanotubes with different graft numbers.
Density functional calculations on the geometric and electronic structures of the endohedral fullerene H2＠C60 and its dimmer
Authors: Bai Yu-Jie  , Fu Shi-You  , Deng Kai-Ming  , Tang Chun-Mei  , Chen Xuan  , Tan Wei-Shi  , Liu Yu-Zhen  , Huang De-Cai  ,   (1)南京理工大学应用物理系,南京  210094; (2)南京理工大学应用物理系,南京  210094；哈尔滨工业大学威海分校,威海  264209
Published: December 2020

Geometric and electronic properties of the endohedral fullerene H2＠C60 and its dimmer have been studied using generalized gradient approximation of density functional theory. It is found that the two hydrogen atoms exist in the form of a molecule in the center of the cage for both H2＠C60 and its dimmer, and the hydrogen molecule can rotate freely at room temperature. The electronic structures of both H2＠C60 and its dimmer show that the formation of hydrogen molecule only affects the energy levels below the Fermi level from -8 to -5eV, while the other energy levels and the energy gap between HOMO and LUMO hardly have any change.
The influence of helium bubble on the elastic properties of aluminum
Authors: Wang Hai-Yan  , Zhu Wen-Jun  , Song Zhen-Fei  , Liu Shao-Jun  , Chen Xiang-Rong  , He Hong-Liang  ,   (1)北京师范大学物理系，北京  100875; (2)四川大学物理科学与技术学院，成都  610064; (3)四川大学物理科学与技术学院，成都  610064；中国工程物理研究院流体物理研究所冲击波物理与爆轰物理重点实验室，绵阳  621900; (4)中国工程物理研究院流体物理研究所冲击波物理与爆轰物理重点实验室，绵阳  621900
Published: December 2020

The elastic properties of helium-bubble embedded aluminum have been investigated by molecular dynamics simulation. First, the interaction potentials between aluminum and helium atoms are parametrized with the help of first-principle method. Secondly, we studied the influence of helium bubble on the elastic properties of aluminum from the following two aspects: the size of helium bubble (the diameters being 16, 20, 25, 30 and 3.5nm, respectively) and the internal pressure of helium bubble (the ratios of the number of helium atoms to the vacancies being about 5%, 15%, 45% and 85%, respectively). The results show that the elastic constants c11, c12 and c44 decrease with increasing diameter of helium bubble, however, for a fixed size they are almost independent of the internal pressure of helium bubble. Using the elastic composite system model, the influence of the size and internal pressure of helium bubble on aluminum is explained qualitatively based on the analytical results and is consistent with our calculated results.
The effect of via size on the stress migration of Cu interconnects
Authors: Wu Zhen-Yu  , Yang Yin-Tang  , Chai Chang-Chun  , Li Yue-Jin  , Wang Jia-You  , Liu Bin  ,   西安电子科技大学微电子学院，宽禁带半导体材料与器件教育部重点实验室，西安  710071
Published: December 2020

Accelerated stress-migration testing under 200℃ of Cu (M1/M2) interconnects has been done for 700h. Finite element analysis and focused-ion beam techniques have been used to study the stress-induced voiding in the Cu interconnects with vias of 500 and 350nm in diameter. The voiding mechanism and the effect of via size on the stress migration have been studied. The results show that peak values of stress and stress gradient in M1 lines are reached underneath the edge of vias. The stress gradient shows crucial effect on the voiding process. The vacancies introduced by thermo-mechanical stress diffuse along Cu M1/SiN interfaces under the force of stress gradient and nucleate at the peak values of the stress gradient. The void grows faster along the length direction because the stress in M1 lines changes faster horizontally. The stress and stress gradient increase with increasing via diameter, leading to a faster voiding rate.
F-substituent on the photoswitchable performance of diarylethenes
Authors: Zhao Peng  , Fang Chang-Feng  , Xia Cai-Juan  , Wang Yi-Ming  , Gao Kun  , Liu De-Sheng  , Xie Shi-Jie  ,   (1)山东大学物理与微电子学院，山东大学晶体材料国家重点实验室，济南  250100; (2)山东大学物理与微电子学院，山东大学晶体材料国家重点实验室，济南  250100；济南大学理学院，济南  250022; (3)山东大学物理与微电子学院，山东大学晶体材料国家重点实验室，济南  250100；山东济宁学院物理系，曲阜  273100
Published: December 2020

Based on ab initio methods and nonequilibrium Green's function theory, we have investigated the photoswitching mechanism of diarylethenes with a phenyl linker and the effect of F-substituent on the photoswitchable performance. Numerical results show that the current through the closed-state system is larger than that through the open-state system under small bias, indicating the switching behavior is stable under small bias, and the photoswitchable performance can be improved by F-substituent significantly.
Electronic structure and optical properties of ZnSe under high pressure
Authors: Ji Zheng-Hua  , Zeng Xiang-Hua  , Hu Yong-Jin  , Tan Ming-Qiu  ,   (1)扬州大学物理科学与技术学院，扬州  225002; (2)浙江大学物理系，杭州  310027
Published: December 2020

We have calculated the electronic structure and optical properties of zinc blende structure ZnSe under different high pressure by means of plane wave pseudo-potential method (PWP) with generalized gradient approximation (GGA) in this paper. The total energy, density of state, energy band structure, and optical absorption and reflection properties under high pressure are calculated. Furthermore, we analyzed the change of electron structure, band structure and optical properties under high pressure using the results of experiment and theory.
Effects of S doping on electronic structures and photocatalytic properties of anatase TiO2
Authors: Zhao Zong-Yan  , Liu Qing-Ju  , Zhu Zhong-Qi  , Zhang Jin  ,   云南大学,云南省高校纳米材料与技术重点实验室，昆明  650091
Published: December 2020

The crystal structure, impurity formation energy, electronic structure and optical properties of anatase TiO2 doped with sulfur in different valence states were studied by using the plane-wave ultrasoft pseudopotential method based on first_principles. The calculations shown that the existence form of sulfur element in anatase TiO2 was related to the experimental conditions; the octahedral dipole moments were increased due to the changes of lattice parameters, bond length and charges on atoms; the band gap narrowed and the curves of light absorption red-shifted to visible-light region due to the position of conduction band downward shifting, the position of valence band upper shifting and the width of valence band broadening result from hybridizing S 3p states with O 2p states and Ti 3d states. All of these results can explain the better photocatalytic properties of S-doped anatase TiO2 in visible-light region. According to these results, the effects on electronic structures and photocatalytic properties of anatase TiO2 doping with different valence states of sulfur were compared and analyzed.
Study of rutile (110) surface STM image via ab initio simulation
Authors: Xiao Bing  , Feng Jing  , Chen Jing-Chao  , Yan Ji-Kang  , Gan Guo-You  ,   (1)昆明理工大学材料与冶金工程学院，昆明  650093; (2)昆明理工大学稀贵及有色先进材料教育部重点实验室及云南省新材料制备与加工重点实验室,昆明  650093; (3)昆明理工大学稀贵及有色先进材料教育部重点实验室及云南省新材料制备与加工重点实验室,昆明  650093；昆明理工大学材料与冶金工程学院，昆明  650093
Published: December 2020

First principle calculations based on DFT have been applied to study various properties of rutile (110) surface. We used a nine_layer slab model with stoichiometric formula of TiO2 and the vacuum length of the cell fixed at 15nm. The interactions between ionic core and valence electrons were represented by pesudopotentials. After analyzing the results, we found that an admixture bonding states existed in titanium dioxide: a stronger ionic bond accompanied by a weaker covalent bond between Ti and O. STM(Scanning tunneling microscope)image of Rutile (110) surface has been successfully simulated by DFT calculations, which was in accord with the Tersoff-Hamann's theory. A positive basis voltage of 2V was added to simulate STM experimentd conditions in imaging process. The distance between tip and surface were also changed step by step. By analyzing the electron density map and DOS plot, it is clear that electron factors dominated the STM image of rutile (110) surface and the jut in the image corresponded to 5_coordinated Ti atom rather than the bridge oxygen on the top.
Investigation of martensitic transition and inverse magnetocaloric property in Ni-Mn-Sn Heusler alloys
Authors: Jing Chao  , Li Zhe  , Chen Ji-Ping  , Lu Yu-Ming  , Cao Shi-Xun  , Zhang Jin-Cang  ,   上海大学物理系，上海  200444
Published: December 2020

The martensitic transition and magnetocaloric property in Ni50Mn25+xSn25-x (x=11, 12) Heusler alloys were investigated by means of structure and magnetism measurements. The results show that the antiferromagnetic interaction strengthens in the martensitic state, leading to the coexistence of ferromagnetic and antiferromagnetic interaction in this state, which is different from the magnetic property of austenitic state in these alloys. Furthermore, based on Maxwell equation, the inverse magnetocaloric property near martensitic transition temperature of this system was studied. It was found that large positive magnetic entropy change (ΔSM) depends on both magnetic jumping (ΔM) and temperature region during martensitic transition.
Room temperature visible photoluminescence from nanocrystalline GaN∶Er film prepared by sputtering
Authors: Pan Xiao-Jun  , Zhang Zhen-Xing  , Wang Tao  , Li Hui  , Xie Er-Qing  ,   兰州大学物理科学与技术学院,兰州  730000
Published: December 2020

GaN:Er thin film has been prepared by direct current (DC) planar magnetron reactive sputtering deposition. The film was characterized by X-ray diffraction (XRD), ultraviolet—visible (UV—Vis) spectroscopy, transmission electron microscope (TEM) and photoluminescence (PL) spectroscopy, XRD shows the structure of the film was nano/poly-crystalline. The average grain size of the film was derived from XRD peaks using the Scherrer formula and the value was 58nm. TEM result indicated that the film was GaN nano-particles embed in amorphous matrix and the particle size was between 6—8nm. UV—Vis transmission spectrum shows that the transmission ratio of the film exceeds 80% in the visible zone from 500nm to 700nm. From UV-Vis spectrum, the optical band gap of the film was calculated using Tauc plot and the value was 322eV. Last, PL was measured by fluorescence spectrometer at room temperature and green emission of Er3+ ions was clearly observed for the transition: 4S3/2(2H11/2)—4I15/2(554nm).
Coupling scattering effect between grain boundary and point defect on the thermoelectric transport process in Co1-xNixSb3-ySey
Authors: Liu Wei-Shu  , Zhang Bo-Ping  , Li Jing-Feng  , Zhang Hai-Long  , Zhao Li-Dong  ,   (1)北京科技大学材料科学与工程学院无机非金属材料系,北京  100083; (2)北京科技大学材料科学与工程学院无机非金属材料系,北京  100083；清华大学材料科学与工程系新型陶瓷与精细工艺国家实验室,北京  100084; (3)清华大学材料科学与工程系新型陶瓷与精细工艺国家实验室,北京  100084
Published: December 2020

Ni and Se co-doped skutterudite compounds Co1-xNixSb3-ySey with fine grains were fabricated by combining mechanical alloying and spark plasma sintering. The coupling effect between grain boundary scattering and point defect scattering on the thermoelectric transport properties was focused.The enhanced power factor by co_doping is twice that of the sample without Ni and achieved a maximum value of 1750μWm-1K-2 at 450℃ for x=0.1. Due to the coupling scattering effect, the lattice thermal conductivity at room temperature decreased to 1.67Wm-1K-1, which approach the reported minimum of 1.60Wm-1K-1, whareas the improved ZT value reached 0.53 at 450℃ for the Co0.9Ni0.1Sb2.85Se0.15. A suggested model shows that the decreased thermal conductivity is duc to the coupling effect between grain boundary scattering and point defect scattering, The calculated values are in good agreement with experimental results. The simulated results also suggest that the lattice thermal conductivity could be further decreased to 0.8Wm-1K-1 when the grain size was reduced to 50nm.
Microstructure dependence of the electroresistance of Nd0.7Sr0.3MnO3
Authors: Chen Shun-Sheng  , Yang Chang-Ping  , Deng Heng  , Sun Zhi-Gang  ,   (1)湖北大学物理学与电子技术学院,铁电压电材料与器件湖北省重点实验室，武汉  430062; (2)武汉理工大学，材料复合新技术国家重点实验室，武汉  430070
Published: December 2020

Nd0.7Sr0.3MnO3 ceramics of perovskite-type were respectively prepared by solid-state reaction and high-energy ball milling with post heating-treatment. The samples obtained using these methods show a great of difference in electrical transport despite having the same crystallographic structure, similar grain size and chemical composition. For the sample prepared by solid-state reaction, the electrical resistance keeps unchanged with current loads and no electroresistance effect takes place. However, for the sample prepared by high-energy ball milling with post heating treatment, the electrical resistance decreases remarkably with increasing current loads and shows colossal electroresistance effect. The microstructure of materials, in particular the screw dislocation-like structure, is supposed to be responsible for the difference in electrical transport.
2-D analytical modeling of dual material gate fully depleted SOI MOSFET with high-k dielectric
Authors: Luan Su-Zhen  , Liu Hong-Xia  , Jia Ren-Xu  , Cai Nai-Qiong  ,   西安电子科技大学微电子学院,宽禁带半导体材料与器件教育部重点实验室,西安  710071
Published: December 2020

A 2-D analytical model for the surface potential and threshold voltage in fully depleted dual-material gate(DMG) SOI MOSFETs with high-k dielectric is developed to investigate the short-channel effects(SCEs). Our model takes into account the effects of the length of the gate metals and their work functions, the applied drain biase,and the gate dielectric constant. We demonstrate that the surface potential in the channel region exhibits a stepped potential variation by the gate near the drain, resulting in suppressed SCEs. With dielectric constants increasing, this novel device shows inverse SCEs. The derived analytical models are in good agreement with the resafts of the two-dimensional device simulator ISE.