bluuebunny/crossref_metadata_2025 huggingface dataset:
Influences of pumping manners on characteristics of all-fiber acousto-optic Q-switched lasers under different pulse repetition rates
Authors: Huang Lin  , Dai Zhi-Yong  , Liu Yong-Zhi  ,   电子科技大学光电信息学院，成都  610054
Published: December 2020

The rate equations of all-fiber acousto-optic Q-switched lasers were solved under different initial boundary conditions by numerical simulation, and the distribution of upper-level population density along the doped fiber under forward pumping and backward pumping, and the relations between pulse energy, average power, pulse width, stored energy and pulse repetition rate, signal transmittance of the pump coupler, and pump power, were obtained. The simulation was analyzed from the viewpoint of the amplified spontaneous emission light, and an all-fiber Y3+b-doped acousto-optic Q-switched laser was employed experimentally to test the effect of pumping manners on the average power and pulse width. The results show that pumping manners significantly affect the performance of all-fiber acousto-optic Q-switched lasers under different pulse repetition rates, so the lasers should be forward pumped for better characteristics of output pulses under lower pulse repetition rate, and they should be backward pumped under higher pulse repetition rate.
Transmission properties of terahertz wave in finite conductance metal-coated hollow waveguide
Authors: Zhang Yu-Ping  , Zhang Hui-Yun  , Geng You-Fu  , Tan Xiao-Ling  , Yao Jian-Quan  ,   (1)山东科技大学理学院，青岛  266510; (2)天津大学精密仪器与光电子工程学院，激光与光电子研究所，天津  300072
Published: December 2020

The transmission properties of terahertz （THz） wave in metal-coated hollow waveguide are studied. Based on the characteristic equation of THz electromagnetic wave in metallic hollow waveguide， the dependence of the transformation attenuation and phase constant on the frequency of THz wave， inner radius of the waveguide and conductance of the metal material is simulated by using the Newton-Raphson iterative method. The results show that， the transformation attenuation can be decreased effectively by using large radius waveguide and high conductance coating metal.
Influence of growth temperature on properties of AlGaInN quaternary epilayers
Authors: Liu Qi-Jia  , Shao Yong  , Wu Zhen-Long  , Xu Zhou  , Xu Feng  , Liu Bin  , Xie Zi-Li  , Chen Peng  ,   (1)南京大学物理系，南京  210093; (2)南京大学扬州光电研究院，扬州  225009; (3)南京大学扬州光电研究院，扬州  225009；南京大学物理系，南京  210093
Published: December 2020

Aluminum gallium indium nitride（AlGaInN） quaternary epilayers were prepared by metalorganic chemical vapor deposition （MOCVD） on c-plane sapphire （α-Al2O3） substrates. Three samples were grown under different temperatures of 800 ℃，850 ℃ and 900 ℃. It is found that the In composition monotonically decreases with the increasing growth temperature，while the Al composition is nearly invariable. The V-pits appeared when the growth temperature increases to 850 ℃, and the size and density of V-pits drastically decrease and the nucleation of V-pits is passivated when the growth temperature rises to 900 ℃ due to the desorption enhancement of segregated In atoms.
Effect of Al2O3 dielectric layer thickness on the AlGaN/GaN metal-oxide-semiconductor higher-electron-mobility transistor characteristics
Authors: Bi Zhi-Wei  , Feng Qian  , Hao Yue  , Yue Yuan-Zheng  , Zhang Zhong-Fen  , Mao Wei  , Yang Li-Yuan  , Hu Gui-Zhou  ,   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

Three kinds of metal-oxide-semiconductor high-electron-mobility transistors （MOS-HEMTs） with different thickness of Al2O3 dielectric layer were fabricated on the same wafer by atomic layer deposition. The measurement results of MOS capacitance，gate leakage current，and the output and transfer characteristics indicate that the control capability of the gate on two-dimentional electron gas will be reduced，while the gate leakage current will be decreased and the breakdown voltage will be increased with the increase of the Al2O3 dielectric layer thickness. Our analysis shows that the thinner the dielectric layer is，the greater the gate capacitance will be，which leads to greater negative shift of threshold voltage and much poorer insulating performance in restraining gate leakage current. Otherwise，with the increase of dielectric layer，higher gate voltage will be applied to obtain higher maximum saturation current density. Moreover，a thorough analysis of the transconductance and the capacity-voltage （C-V） characteristic shows that better passivation effect and insulating performance can be obtained with thicker dielectric layers.
Effects of magnetic field on organic electroluminescence
Authors: Wang Jin  , Hua Jie  , Ding Gui-Ying  , Chang Xi  , Zhang Gang  , Jiang Wen-Long  ,   吉林师范大学信息技术学院, 四平  136000
Published: December 2020

Electrofluorescent organic light-emitting device with the structure of ITO/NPB/Alq3/LiF/Al and electrophosphorescent device with the structure of ITO/NPB/CBP: Ir（ppy）3/BCP/Alq3/LiF/Al were fabricated. Their electroluminescence properties were measured under an external magnetic field of 50 mT. Compared to the case of without magnetic field, the electroluminescent（EL） efficiencies of the above-mentioned two kinds of devices increase 44% and 7%, respectively. Based on the luminescence mechanism of organic light-emitting diodes （OLEDs）, the observed phenomena were explained. The origin of the improvement can be attributed to the Zeeman split of triplet state due to the external magnetic field influence, resulting in the conversion of triplets T+ into singlet S in the electrofluorescent device and an increase of the rate constants of triplet energy transfer from host to guest in electrophosphorescent device, respectively. At the same time, the reduced concentrations of triplet decreases the interaction of triplets with free carriers, resulting in an increase in the mobility of free carriers within the device and hence increasing the current.
Effects of p-seeding layer on the performance of microcrystalline silicon solar cells deposited in single chamber
Authors: Wang Guang-Hong  , Zhang Xiao-Dan  , Xu Sheng-Zhi  , Sun Fu-He  , Yue Qiang  , Wei Chang-Chun  , Sun Jian  , Geng Xin-Hua  , Xiong Shao-Zhen  , Zhao Ying  ,   南开大学光电子薄膜器件与技术研究所，光电信息技术科学教育部重点实验室，光电子薄膜器件与技术天津市重点实验室，天津  300071
Published: December 2020

The p-i-n type μc-Si:H solar cells were prepared in a single chamber using very high frequency plasma enhanced chemical vapor deposition technique. Boron cross-contamination between p-layer and subsequent i-layer seriously affects the device performance. The effects of p-seeding on the μc-Si:H i-layers and performance of μc-Si:H solar cells were investigated.The p-seeding method was mainly realized by relatively high hydrogen rich plasma. It has been demonstrated that p-seeding can improve the characteristics of p/i interface and the vertical uniformity of the intrinsic layer and reduce boron contamination. Through the optimization of p-seeding layer technique, a-Si:H/μc-Si:H tandem solar cell with 881% （1 cm2） conversion efficiency has been fabricated in single chamber.
Subjective evaluation and analysis of auditory attributes for underwater noise
Authors: Wang Na  , Chen Ke-An  , Huang Huang  ,   西北工业大学航海学院环境工程系,西安  710072
Published: December 2020

Dimensionality and the corresponding physical characteristics of auditory attribute space for equal-loudness underwater noise are investigated. Firstly, cluster analysis and questionnaire surveys are performed to obtain a number of auditory attribute descriptors in Chinese language, and then based on paired comparison and semantic differential approach, a dissimilarity matrix and a subjective evaluation value of each descriptor are obtained. Finally, by use of multidimensional scaling and principal component analysis, auditory attribute space of underwater noise with equal-loudness and equal-duration is determined and then the five-dimensional space is composed by dark-roughness, fluctuation, fast-variety, sharpness and regularity.
Two-dimensional simulation of high-frequency-induced large-scale irregularities in F region
Authors: Deng Feng  , Zhao Zheng-Yu  , Shi Run  , Zhang Yuan-Nong  ,   武汉大学电子信息学院,武汉  430079
Published: December 2020

When the high-power high frequency （HF） wave is pumped into the ionosphere, the pump wave reflection region is another main heated area. We setup a two-dimensional model of HF ionospheric heating in the magnetic meridian at lower latitude, and obtain results according to the background parameters of the morning and evening. We find that the electronic temperature around the pump wave reflection region increases intensively, and the electronic density decreases in the same area. The electronic density increases in the areas above and under the magnetic line of the electronic density hole. The ionospheric heating effect in the evening is much obvious than that in the morning, for which the maximum change rates of electronic density are -13% and -3.6% respectively, and the maximum change rates of electronic temperature are 88% and 22%, respectively.
Mei symmetries and the Noether conserved quantities of super-thin elastic rod
Authors: Cui Jian-Xin  , Gao Hai-Bo  , Hong Wen-Xue  ,   燕山大学电气工程学院，秦皇岛  066004
Published: December 2020

Based on Kirchhoff’s analogue，generalized Hamilton canonical equations for the dynamics of super-thin elastic rod are analyzed. The Mei symmetry transformations and the theorem are introduced.And the condition and theorem of Noether conserved quantity are deduced directly by Mei symmetry for the super-thin elastic rod system. An example is given to illustrate the application of the result.
Langevin model of the flow control in the internet and its phase transition analysis
Authors: Fan Hua  , Li Li  , Yuan Jian  , Shan Xiu-Ming  ,   清华大学电子工程系,北京  100084
Published: December 2020

One of the big challenges in the field of Internet research is to elucidate the relationship between micro-algorithms of the flow control protocols and macro-properties of the Internet with a proper model. In this paper, we build up a Langevin equation under the transmission control protocol using deductive method. Then we analyze the effectiveness of the active queue management based on the Langevin model. We have proved that there is a phase transition sequence from smooth state to congestion state then to paralysis state in all such kind of algorithms. We also provide explicit formulas of the critical points in terms of the system parameters. Although the model used in this paper focuses on a specific algorithm, we believe this method has a great potential in analyzing and understanding various network congestion control algorithms.
The synchronization of spatiotemporal chaos of all-to-all network using nonlinear coupling
Authors: Jing Xiao-Dan  , Lü Ling  ,   (1)辽宁师范大学物理与电子技术学院,大连  116029; (2)辽宁师范大学物理与电子技术学院,大连  116029；辽宁工业大学数理科学系,锦州  121001
Published: December 2020

N Fitzhugh-Nagumo models are used as network nodes, and synchronization of spatiotemporal chaos is studied using a all-to-all network constructed through a nonlinear coupling. The general principle of selecting coupling functions between nodes of the complex network is introduced. The theoretical analysis of the conditions for synchronization is made and the range of the feedback gain is obtained based on Lyapunov stability theory. The simulation is made to test the synchronization effect of the spatiotemporal chaos of the all-to-all network whose nodes are Fitzhugh-Nagumo models. The results show that the synchronization is fast and efficient, and the size of the network size has no sensitive effect on the stability of the network synchronization.
Study of multilevel pulse train control technique for switching converters
Authors: Qin Ming  , Xu Jian-Ping  ,   西南交通大学电气工程学院，成都  610031
Published: December 2020

A new control technique, multilevel pulse train （MPT）, for switching converters is proposed in this paper. By using MPT control, according to different operation states, multilevel pulses are combined to generate a multilevel pulse train for the control of switching converters. MPT control technique is easy to realize, with great robust ness and good transient performance. The principle and implementation of the control technique are introduced, and the operation, characteristics and small-signal model of MPT controlled buck converter are also studied. The analysis, simulation and experimental results show that MPT control technique has much faster transient response than traditional PWM control technique and much lower output voltage ripple than the pulse train control technique.
A theoretical scheme for zero-knowledge proof quantum identity authentication
Authors: Wang Yu-Wu  , Zhan You-Bang  ,   (1)淮阴师范学院计算机科学系,淮安  223300; (2)淮阴师范学院物理系,淮安  223300
Published: December 2020

A theoretical scheme for zero-knowledge proof quantum identity authentication is proposed by the absolutely impartial third party CA， which has been realized based on remote state preparation and assisted cloning controlled means. In the process of identification， only CA knows the information of quantum identity card and the first party Alice and the second party Bob can accomplish the quantum identity authentication without knowing it. We discuss the probability of accomplishing this job. The security of this scheme is unconditional and it is guaranteed by quantum mechanism.
Phase-field simulation of non-isothermal solidification dendrite growth of binary alloy under the force flow
Authors: Long Wen-Yuan  , Lü Dong-Lan  , Xia Chun  , Pan Mei-Man  , Cai Qi-Zhou  , Chen Li-Liang  ,   (1)华中科技大学材料科学与工程学院,武汉  430074; (2)南昌航空大学航空制造工程学院,南昌  330063
Published: December 2020

Based on the binary phase-field model, the phase-field model coupling with solute field，temperature field and flow field was developed. The mass and momentum conservation equations are solved by using the Simple algorithm, and the thermal governing equation is numerically solved using an alternating implicit finite difference method. The dendrite growth processes during isothermal and non-isothermal solidification of the binary alloy under convection was simulated. The difference in dendrite growth, solute distribute and temperature distribution were investigated. The result of dendrite growth during isothermal and non-isothermal solidification were compared.The effect of latent heat on the dendrite growth under convection was analyzed.
Interface treatment of amorphous silicon thin film solar cells on flexible substrate
Authors: Cai Hong-Kun  , Tao Ke  , Wang Lin-Shen  , Zhao Jing-Fang  , Sui Yan-Ping  , Zhang De-Xian  ,   (1)南开大学信息技术科学学院电子科学与技术系，天津  300071; (2)南开大学信息技术科学学院电子科学与技术系，天津  300071；天津市光电子薄膜器件与技术重点实验室，天津  300071
Published: December 2020

The experiment and AMPS modeling have been used to analyze the characteristics of a-Si solar cells on flexible substrate with different buffer layers at the i/p interface. Combining with technology parameters, this paper uses different band gap and the defect density of states of the interface layer to simulate the characteristics of solar cells. The modeling results show that the solar cells are deteriorated by the interface layer with a big band gap and large defect density of states. By optimizing treatment of i/p interface, the amorphous silicon solar cell on polyimide substrate has been achieved with an efficiency of 7.09%.
Tailoring the morphology and wettability of ZnO one-dimensional nanostructures
Authors: Wu Xiang  , Cai Wei  , Qu Feng-Yu  ,   (1)哈尔滨工业大学材料科学与工程学院，哈尔滨  150001; (2)哈尔滨师范大学化学化工学院，哈尔滨  150025
Published: December 2020

Diverse one-dimensional （1D） nanostructures of ZnO, such as tower-like, conical, mushroom-like and ring-like， have been synthesized through vapor phase deposition method using metals and semiconductors as the substrates. SEM and TEM are used to characterize the morphologies and microstructures of as-synthesized products. Results indicate that the substrates have important effect on the morphology and structure of as-synthesized products.The growth mechanism of as-grown tower-like nanostructure is explained and the corresponding wettability is studied.
Electromagnetic mode analysis on the cold characteristics of photonic-band-gap resonant cavity loaded in gyrotron
Authors: Liu Chang  , Luo Yao-Tian  , Tang Chang-Jian  , Liu Pu-Kun  ,   (1)四川大学应用物理系,成都  610065; (2)四川大学应用物理系,成都  610065；解放军后勤工程学院基础部，重庆  400016; (3)中国科学院电子学研究所，北京  100080
Published: December 2020

The traditional cylindrical resonant cavity loaded in gyrotron is substituted by the photonic-band-gap resonant cavity （PBGC） which is constructed by triangular arrays of metal posts, and the TE operating modes in PBGC are analyzed and calculated. Under the consideration of the cavity structure features, a research method for the mode theory on PBGC is provided. The single-mode operation in the cavity is found, and the distribution characteristics of the azimuthally inhomogeneous electromagnetic modes are reported. The research results show that the resonant frequency in the cavity can be excited without the limitation of transverse dimension. The study provides a physical theoretical fundamental of which reveals the possibility of changing the operating status of gyrotron essentially. This possibility will play an important role in the following aspects: enhancing the power capacity of cavity, carrying out the beam-wave interaction between high order electromagnetic single-mode and high electronics cyclotron harmonic wave efficiently, and reducing the gyrotron operating magnetic field.
Dependence of sensitivity of atom interferometer gravimeters on the Raman laser pulse sequences
Authors: Ren Li-Chun  , Zhou Lin  , Li Run-Bing  , Liu Min  , Wang Jin  , Zhan Ming-Sheng  ,   (1)中国科学院武汉物理与数学研究所波谱与原子分子物理国家重点实验室,武汉  430071；中国科学院冷原子物理中心，武汉  430071; (2)中国科学院武汉物理与数学研究所波谱与原子分子物理国家重点实验室,武汉  430071；中国科学院冷原子物理中心，武汉  430071；中国科学院研究生院，北京  100049
Published: December 2020

We investigate the dependence of the sensitivity of atom interferometer gravimeter on the Raman laser pulse sequence. The sensitivity of atom gravimeter can be adjusted by changing the pulse duration. Under the standard pulse configuration condition, the atom interferometer with four pulses is insensitive to the gravity if only gravity and its first order gradient are taken into account. The three-pulse Raman atom interferometer gravimeter displays best sensitivity. Atom interferometers with more than four Raman pulses show poorer sensitivity.
Scattering of a beam with orbital angular momentum by a single sphere
Authors: Lü Hong  , Ke Xi-Zheng  ,   西安理工大学自动化与信息工程学院，西安  710048
Published: December 2020

The propagation properties and scattering characteristic of a beam with orbital angular momentum transmission were researched by using the generalized Lorenz-Mie theory. Based on the research on the scattering of the Gaussian beam from single sphere，the intensity distributions of LGB beam at different propagation distance is analyzed. Without considering the relation between scattering and phase shift，the beam coefficients is obtained by the solution of scattering cross section，and the LGB is expanded in terms of the vector spherical harmonics as fundamental Gaussian beam. The scattering of the beam with orbital angular momentum from single sphere located on the propagation axis is studied. The influence of scattering intensity and angular distribution on scattering characteristic for different beam width is discussed by numerical simulation，and compared with those for the plane wave. The results show that when the beam waist radius is very small，the beam waist radius has serious influence on the decay rate. When the beam waist radius is relatively large，the influence is similar to that of plane wave.
Generation of plasma current under arbitrary strong direct current electric field
Authors: Weng Su-Ming  , Sheng Zheng-Ming  , Zhang Jie  ,   (1)中国科学院物理研究所,北京凝聚态物理国家实验室，北京  100190; (2)中国科学院物理研究所,北京凝聚态物理国家实验室，北京  100190；上海交通大学物理系，上海  200240
Published: December 2020

The generation of plasma current and the evolution of electron distribution under arbitrarily strong direct current electric fields have been studied by Fokker-Planck simulation. It is found that the behaviors of plasma are different under different fields: in the weak field, Spitzer’s law is suitable for describing the relationship between plasma current and electric field, and the response time to generate current is approximately equal to the relaxation time to reduce current after switching off the electric field; in the moderate field, the electron distribution is well represented by the sum of a stationary and drifting Maxwellian, and the relaxation time is much longer than the response time. According to the detailed knowledge of electron distributions, a set of hydrodynamic-like equations, similar to Spitzer’s but without the weak-field limit, is given for calculating the current. It is more suitable for application in hybrid particle-in-cell simulations.
Electronic noise of diluted magnetic semiconductor (Ga,Mn)As around Curie point
Authors: Yang Wei  , Ji Yang  , Luo Hai-Hui  , Ruan Xue-Zhong  , Wang Wei-Zhu  , Zhao Jian-Hua  ,   (1)中国科学院半导体研究所，北京  100083; (2)中国科学院半导体研究所，北京  100083；中国科学院研究生院，北京  100049
Published: December 2020

We have studied the spontaneous fluctuation noise spectrum of （Ga,Mn）As in frequency domian from 1 kHz to 250 kHz. We found that the electronic noise can be reduced by a magnetic field and its magnitude increases with increasing temperature of the （Ga,Mn）As sample. The electrical noise spectra at different frequencies have different temperature dependence and their amplitude changes at the phase transition temperature, suggesting that the phase transition process of （Ga,Mn）As is subtly different from normal magnetic materials. Our results may help understanding the origin of magnetism in （Ga,Mn）As.
Two-step thermoelastic martensitic transformation and stress-strain characteristic of Ni53.2Mn22.6Ga24.2 single crystal
Authors: Cui Yu-Ting  , You Su-Qin  , Wu Liang  , Ma Yong  , Chen Jing-Lan  , Pan Fu-Sheng  , Wu Guang-Heng  ,   (1)中国科学院物理研究所北京凝聚态物理国家实验室,北京  100080; (2)重庆大学材料科学与工程学院，重庆  400044; (3)重庆师范大学物理与信息技术学院，重庆  400047; (4)重庆师范大学物理与信息技术学院，重庆  400047；重庆大学材料科学与工程学院，重庆  400044
Published: December 2020

Physical properties of the two-step complete thermoelastic Ni53.2Mn22.6Ga24.2 single crystal are investigated by various measuring methods, especially, the stress-strain characteristic at different temperatures is studied. The results show that at low deformation temperatures the pressing stress along the ［001］ direction of the parent phase would induce a two-step martensitic transformation, and the alloy exhibits pseudoelastic characteristics. But at relatively high temperatures, the alloy exhibits complete superelastic characteristics, and only one-step martensitic transformation is observed. Furthermore, the dependence of critical stress on the deformation temperature for the martensitic transformation and intermartensitic transformation is calculated by the thermodynamic theory, and the result is consistent with that of two-step martensitic transformation obtained by experiment.
Revision of quantum efficiency formula for negative electron affinity photocathodes
Authors: Du Xiao-Qing  , Chang Ben-Kang  ,   (1)南京理工大学电子工程与光电技术学院，南京  210094; (2)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

Quantum efficiency （QE） is one of the most important characteristics of photoemission performance of negative electron affinity （NEA） photocathodes. The quantum efficiency formulas for NEA photocathodes show the influences of photocathode parameters on photoemission performance and also provide theoretical guidance for optimum design of photocathodes. The photoemission process in bulk and surface of NEA photocathodes is firstly analyzed. Surface electron escape probability and attenuation length are respectively revised considering the effects of incident photon energy，surface band bending region and surface barrier on photoemission. The quantum efficiency formulas for NEA photocathodes are established by integration method. The theoretically estimated QE curve is consistent with the experimental one，which validates the practicability of the revised QE formula. This work can provide theoretical references for research of NEA photocathodes.
Three-dimensional numerial simulation of single event upset effects in static random access memory
Authors: Zhang Ke-Ying  , Guo Hong-Xia  , Luo Yin-Hong  , He Bao-Ping  , Yao Zhi-Bin  , Zhang Feng-Qi  , Wang Yuan-Ming  ,   西北核技术研究所，西安  710024
Published: December 2020

Three-Dimensional model of static random access memory （SRAM） six-transistor cell is generated by three dimensional process simulator FLOOPS, and device simulator DESSIS is used to simulate the single-event upset effect in SRAM. Single-event upset and charge collecting maps are calculated directly from 3-D simulations. Single event upset maps and cross-section curves obtained from numerial simulation show excellent agreement with broad beam cross section curves and micro-beam upset images for 2 kbit hardened SRAM. It indicates that the three-dimensional model could be used to research the single event upsets in SRAM.
Numerical simulation of the tribological behaviour of the serial coatings of D2 steel
Authors: Wang Ke-Sheng  , Liu Quan-Kun  , Zhang De-Yuan  ,   (1)合肥工业大学材料科学与工程学院,合肥  230009; (2)合肥工业大学材料科学与工程学院,合肥  230009；深圳怡景五金制品有限公司,深圳  518103
Published: December 2020

By using the vacuum ion plating technique, nitriding, titanium nitride and their complex coatings are plated on AISI D2 steel, and the finite element analysis （FEA） and experiments are employed to investigate their wear resistance. Archard adhesive wear law based on classic model is embedded into the commercial FEA software in the manner of Fortran subroutine, thereby calculating the wear depth of each node during the contact friction process. The wear depths of substrate and three kinds of coatings are quantitatively analyzed. It is shown that duplex treatment has an optimal wear resistance, and the simulation results are in good agreement with experimental measurements.
A novel quartz micro-structure based on shear stress detection and its gyroscopic effect
Authors: Xie Li-Qiang  , Wu Xue-Zhong  , Li Sheng-Yi  , Wang Hao-Xu  , Dong Pei-Tao  ,   College of Mechatronics Engineering and Automation, National University of Defense Technology, Changsha 410073, China
Published: December 2020

In order to simplify sidewall electrode pattern of quartz gyroscope, a novel micro-structure used to sense Coriolis’ force based on shear stress detection is demonstrated. The approach of shear stress detection is analyzed and the structure of sidewall electrode is a single polarity electrode. A tapered beam with 15° taper designed as the sensing beam can increase its sensitivity. A prototype structure is fabricated by processing z-cut quartz by anisotropic wet etching technique. The prototype has a drive mode frequency of about 5.6 kHz, and the quality factor is over 5000 in atmosphere. The spectrum analysis of the structure’s output signal reveals the Coriolis force, which validates our new design scheme.
Design and fabrication of hard X-ray phase grating
Authors: Liu Xin  , Lei Yao-Hu  , Zhao Zhi-Gang  , Guo Jin-Chuan  , Niu Han-Ben  ,   College of Optoelectronic Engineering, Shenzhen University, Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education, Shenzhen 518060, China
Published: December 2020

The x-ray phase grating made on silicon wafer was designed under considerations of the parameters of the phase contrast imaging system, the spatial coherence characteristics of x-ray source and its diffraction efficiency for x-ray of 40—100 keV, which is usually used for phase contrast imaging in laboratories and hospitals. The phase grating with diameter of 5 inch , pitch of 5.6 μm, wall width of 2.8 μm and depth of 40—70 μm depending on the energy of x-ray photon, was fabricated using the technique of photo-assisted electrochemical etching developed in our lab. Two special methods, namely, the enhancement of the voltage applied to the silicon wafer and modification of the current density defined by Lehmann formula, have been used to reduce the lateral etching. A reproducible technique has been developed for fabrication of precise and large x-ray phase grating on silicon wafer.
Fabrication and luminescence characterization of two-dimensional GaAs-based photonic crystal nanocavities
Authors: Wang Zhan-Guo  , Niu Jie-Bin  , Jia Rui  , Peng Yin-Sheng  , Yang Xiao-Hong  , Ye Xiao-Ling  , Xu Bo  , Liang Song  ,   Institute of Micro-electronics, Chinese Academy of Sciences, Beijing 100029, China;,   Key Laboratory of Semiconductor Materials Science, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083,China;,   Key Laboratory of Semiconductor Materials Science, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083,China, College of  Information Engineering, Zhejang University of Technology, Hangzhou 310023, China;,   State Key Laboratory of Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences,Beijing 100083, China
Published: December 2020

This paper describes the design and fabrication process of a two-dimensional GaAs-based photonic crystal nanocavity with InAs quantum dots (QDs) emitters and analyzes the optical characteristics of cavity modes at room temperature. The micro-luminescence spectrum recorded from the nanocavities exhibits a narrow optical transition at the lowest order resonance wavelength of about 1137 nm with about 1 nm emission linewidth. In addition,the spectra of photonic crystal nanocavities processed under different etching conditions show that the verticality of air hole sidewall is an important factor determing the luminescence characteristics of photonic crystal nanocaivties. Finally,the variance of resonant modes is also discussed as a function of r/a ratio and will be used in techniques aimed at improving the probability of achieving spectral coupling of a single QD to a cavity mode.
A fiber decorated by colloidal photonic crystal
Authors: Liu Qing  , Wang Ming  , Guo Wen-Hua  , Yan Hai-Tao  , Yu Ping  ,   School of Physics and Technology, Nanjing Normal University, Jiangsu Key Laboratory on Opto-Electronic Technology, Nanjing 210046, China
Published: December 2020

A method of fabricating fiber decorated by colloidal photonic crystal is devised. Three-dimensional nanostructure colloidal crystal on the end face of optical fiber was grown by isothermal heating evaporation induced self-assembly method. The optical fiber with colloidal crystals was connected to another lapped optical fiber by glass capillary,and the fiber decorated by colloidal photonic crystal was formed. The nanostructural morphology of the colloidal crystal was examined by SEM. The optical characteristics of the colloidal crystal was also analyzed. The spectral feature of the optical fiber colloidal crystal was measured by using optical sensing analyzer. It has been found that the optimal conditions for a good quality crystal are an evaporation temperature of 40 ℃ with a volume fraction of 0.5% and a deposition time of 12 hours.SEM reveals that the colloidal crystal on the end face of optical fiber has face-centered-cubic structure. Transmission measurement shows the existence of photonic band gap,and the stopgap is located at 1365 nm.
Effects of In doping on crystal structure and thermoelectric properties of n-type skutterudites
Authors: Zhou Long  , Li Han  , Su Xian-Li  , Tang Xin-Feng  ,   State Key Laboratory of Advanced Technology for Material Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, China
Published: December 2020

Skutterudite compounds InxCo4Sb12(x=0.1—0.4) have been synthesized by a melt-quench-anneal-spark plasma sintering method. x-ray diffraction (XRD) and filed emission scanning electron microscopy (FESEM) results show that doping of In results in a nano structured InSb phase distributed in the grain boundaries when the content of In exceeds its filling fraction limit in the skutterudites. Furthermore, the content of InSb increases with increasing In content. Our research indicates that the existence of nanostructured secondary phase InSb increases the power factor, decreases the lattice thermal conductivity, and therefore remarkably improves the thermoelectric properties of the compounds. The highest thermoelectric figure of merit ZT=1.21 is achieved at 800 K in the In0.35Co4Sb12 compound.
On the equilibrium conditions for a spherical-cap liquid drop on a solid surface——Also comments on “Thermodynamic mechanism for the condensation of liquid drops on the condense surface” etc.
Authors: Zhu Ru-Zeng  , Yan Hong  , Wang Xiao-Song  ,   State Key Laboratory of Nonlinear Mechanics, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China
Published: December 2020

For a liquid drop of first kind (with the size much bigger than the interface thickness), whether on or far away from a solid surface, it is proved that the classical Laplace equation is valid and the related arguments are clarified. The formula of additional pressure for the liquid drop of the first kind dependent on contact angle, given in Ref. 48 1823] is wrong, the comment of Ref. is correct.
Effect of temperature gradient on space charge waveform in pulsed electroacoustic method
Authors: Chen Xi  , Wang Xia  , Wu Kai  , Peng Zong-Ren  , Cheng Yong-Hong  ,   State Key Laboratory of Electrical Insulation and Power Equipment, Xi’an Jiaotong University, Xi’an 710049, China
Published: December 2020

Temperature rise of power equipment in service serionsly affect the lifetime of insulation, so many researchers have focused on space charge measurements at high temperature. But the changes of polymeric properties (e.g. sound impedance, Young’s modulus, density, velocity of sound wave, decay characteristic etc.) at high temperature make measurement of space charge profiles in polymer inaccurate. What is more, the changes of polymeric properties are more complex under temperature gradient. In this paper, based on the propagation characteristic of sound wave in pulsed electroacoustic method and temperature dependence of polyethylene properties, the effect of temperature gradient on space charge measurement is analyzed and the space charge waveform is recovered.
Model of the relationship between properties and phase composition of zirconia solid electrolyte
Authors: Hu Yong-Gang  , Xiao Jian-Zhong  , Xia Feng  , Wu Xi-Wang  , Yan Shuang-Zhi  ,   (1)Department of Materials Science and Engineering,Huazhong University of Science and Technology,Wuhan 430074, China; (2)Sinosteel Corporation Luoyang Institute of Refractories Research,Luoyang 471039, China
Published: December 2020

The relative content of each phase at room temperature and the ratio of transformable phase at high temperature of zirconia solid electrolyte are important to its thermal shock resistance and electrical conductivity. The match of thermal shock resistance and electrical conductivity plays an important role in measuring the lower oxygen activity in molten steel. A linear model between the thermal shock resistance and the phase composition at room temperature is proposed based on this concept, another evolved relationship between the pyroconductivity and the elevated temperature transformation is also proposed. These models provide theoretical reference for the preparation of the high precision oxygen sensor for measuring the lower partial pressure of oxygen in molten steel.
A parallel immune genetic algorithm in adaptive resource allocation for cognitive radio network
Authors: Zhou Jie  , Zu Yun-Xiao  ,   School of Electronic Engineering, Beijing University of Posts and Telecommunications, Beijing 100876, China
Published: December 2020

A parallel immune genetic algorithm for adaptive modulation and cognitive radio spectrum assignment was developed, and simulations are conducted to compare the parallel immune genetic algorithm method with simple genetic algorithm and non-adaptive modulation algorithm. The simulation results show that the algorithm has strong global searching capability and fast convergence speed, and it is efficient and superior to the simple genetic algorithm and non-adaptive modulation algorithm in case of limited total transmitting power and presence of notable bit error rate, while the computation complexity is reduced significantly.
Energy and spectrum of BeO molecule under the electric field from different directions
Authors: Yan An-Ying  , Jiang Ming  , Zhang Chuan-Wu  , Miao Feng  , Gou Fu-Jun  ,   (1)College of Electrical Information Engineering, Southwest University for Nationalities, Chengdu 610041,China; (2)Institute for Plasma Physics, Rijnhuizen 3430BE Nieuwgein, The Netherlands
Published: December 2020

Based on the density functional theory DFT/ B3LYP at 6-311g level, the ground states of BeO molecule are optimized. The effects of electric field on the bond length, the system energy, the charge distribution, the energy levels, the HOMO-LUMO gaps and the infrared spectrum of BeO molecule are studied. The results indicate that the bond length of BeO molecule increass,but the system energy decreases as the external electric field increases from 0.0 to 0.05 a.u. At the same time, the energy gaps between the HOMO and LUMO become separated with the increase of electric field. It shows that the structure of BeO molecule is steady under external electric field so that oxygen atom in BeO is difficult to combine with hydrogen atom escaping from the reactor.
Study on rate coefficient of dielectronic recombination in dense plasma based on doubly excited state
Authors: Wang Wei  , Jiang Gang  ,   Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, China
Published: December 2020

The method to calculate the rate coefficient of dielectronic recombination (DR) in dense plasma is discussed in this paper. The formula for calculating the DR rate coefficient as a function of electron density is derived under the effects of transition processes among doubly excited states, collisional ionization and autoionization corresponding to doubly excited states. And the calculation results for DR of Ne-like Ni based on the formula are given. The results show the trend of the change in DR rate coefficient as electron density increases. Additionally, the DR rate coefficients under the effects of different atomic processes are given and analyzed.
Geometry, electronic properties and magnetism of FenO+m(n+m=4) clusters
Authors: Xu Ben-Fu  , Yang Chuan-Lu  , Tong Xiao-Fei  , Wang Mei-Shan  , Ma Xiao-Guang  , Wang De-Hua  ,   School of physics, Ludong University, Yantai 264011, China
Published: December 2020

The initial geometries of FenO+m(n+m=4) clusters are built by using the "binomial" scheme. And 12 stable isomers are obtained by optimization and frequency analysis based on the density-functional theory GGA (PW91) and the all-electron numerical basis set. The binding energies, the energy gaps between the highest occupied molecular orbital and the lowest unoccupied molecular orbital, and the magnetic moments of all the stable isomers are determined and analyzed. It is found that Fe—O bonds are important for stabilizing the FenO+m clusters, and that the total magnetic moments of the isomers are mainly dependent on the magnetic moment of iron atoms and the arrangement of the magnetic moments of the atoms.
Inner ionization mechanisms of methane clusters driven by an ultrashort intense laser pulse
Authors: Li Hong-Yu  , Liu Jian-Sheng  ,   (1)College of Physics and Electronic Information, Tianjin Normal University, Tianjin 300387, China; (2)State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China
Published: December 2020

By use of three-dimensional particle dynamics simulations, the explosion dynamics of methane clusters driven by an ultrashort intense laser pulse has been analyzed. Especially the influences of some classical inner ionization mechanisms on the charged state and kinetic energy of the ions produced in the laser-cluster interaction process have been discussed in detail. It is presented that when the laser intensity is low, the atoms are ionized by the laser field mainly through the tunnel ionization while the barrier suppression ionization dominates for the inner ionization as the laser intensity increases. Under the irradiation of the same laser pulse with high intensity, the cluster can attain highly-ionized charged states by the barrier suppression ionization rather than by the tunnel ionization. After the cluster is ionized, the ignition ionization effect from the inner Coulomb field of the cluster and the electron impact ionization effect from the free electrons resided inside the cluster will facilitate the process that the cluster can be ionized further.
Electromagnetic tunneling properties of sandwich structure containing single negative material
Authors: He Li  , Qiao Wen-Tao  , Zhang Li-Wei  , Xu Jing-Ping  ,   (1)Pohl Institute of Solid State Physics, Tongji University, Shanghai 200092, China; (2)School of Physics and Chemistry, Henan Polytechnic University, Jiaozuo 454000,China; (3)School of Physics and Chemistry, Henan Polytechnic University, Jiaozuo 454000,China;Pohl Institute of Solid State Physics, Tongji University, Shanghai 200092, China
Published: December 2020

The electromagnetic tunneling properties of the sandwich structure with single negative material/positive index material (single negative material)/ single negative material are experimentally investigated based on the theoretical analysis. The tunneling properties come from the resonance coupling between the incident plane wave and the surface and bulk polaritons. First, the surface or bulk polariton dispersion relations under zero incident condition are discussed and calculated. It is found that the positive index material sandwiched by single negative material possesses bulk polaritons, the resonance frequency of polariton decreases with the thickness of the central layer increasing. The sandwhic structures composed of different single negative materials possess double surface polaritons, and the two surface polaritons degenerate with the thickness of the central single negative material layer. Subsequently, the tunneling properties of the sandwich structures are measured, which are consistent well with the simulation and theoretical analyses. The two structures both possess tunable tunneling modes, their properties have potential applications in designing tunable single or multiple-channeled filters.
Investigation on viscoelastic behaviors of near-interface 5CB liquid crystal under electric field with quartz crystal microbalance
Authors: Xiong Yi  , Zhang Xiang-Jun  , Zhang Xiao-Hao  , Wen Shi-Zhu  ,   State Key Laboratory of Tribology, Tsinghua University, Beijing 100084, China
Published: December 2020

The influence of electric field on near-interface 4-pentyl-4'-cyanobiphenyl(5CB) liquid crystal (LC) is investigated with quartz crystal microbalance (QCM). The results of QCM show that the process of frequency shifting with electric field, which reflects the viscoelasticity change of 5CB, can be divided into two parts. Then the two-layer model of 5CB is proposed to illuminate the results of QCM, thereby indicating that the effect of electric field on near-interface layer is different from on bulk layer. Quantitative analysis is carried out with two-layer model of QCM, which indicates that there is a near-interface layer of about 100nm, adsorbed on the upper electrode of quartz crystal. The complex shear viscosity of the near-interface layer decreases with electric field strength increasing, which is opposite to the rule of bulk viscosity of 5CB.
Generalized Pfaff-Birkhoff-d’Alembert principle and form invariance of generalized Birkhoff’s equations
Authors: Wang Chuan-Dong  , Liu Shi-Xing  , Mei Feng-Xiang  ,   (1)Department of Mechanics, Beijing Institute of Technology, Beijing 100081, China; (2)Department of Mechanics, Beijing Institute of Technology, Beijing 100081, China;School of Physics,  Liaoning University,  Shenyang 110036,  China
Published: December 2020

The generalized Pfaff-Birkhoff-dAlembert principle and the form invariance of the generalized Birkhoff s equations under the infinitesimal transformation of group are studied. The criterion of the form invariance is given and the Noether conserved quantity and a new conserved quantity are obtained by the invariance.
Implementation of multi-scroll Chua’s circuit by hybrid single electron transistor and metal oxide semiconductor structure
Authors: Feng Chao-Wen  , Cai Li  , Zhang Li-Sen  , Yang Xiao-Kuo  , Zhao Xiao-Hui  ,   College of Science, Air Force Engineering University, Xi’an 710051, China
Published: December 2020

Based on the structure of cellular neural network, multi-scroll Chua’s circuit is implemented by the nanoelectronic device of hybrid single electron transistor and metal oxide semiconductor (SETMOS) structure with its negative differential resistance characteristic. The basic dynamical properties, including phase portrait, bifurcation diagram, Lyapunov exponent spectrum, Poincaré mapping and power spectrum are studied by theoretic analysis and numerical simulation. The validity and the feasibility of three-order Chua’s circuit with four scrolls are further confirmed by the circuit simulation experiment. Finally, the results show that the negative differential resistance characteristic of SETMOS determines complex dynamical behaviors of multi-scroll Chua’s circuit. Also, the designed circuit has simple structure and is easy to realize.
Physics and simulation of terahertz folded waveguide traveling wave tube regenerative feedback oscillators
Authors: Gao Peng  , Booske John H.  , Yang Zhong-Hai  , Li Bin  , Xu Li  , He Jun  , Gong Yu-Bin  , Tian Zhong  ,   (1)Department of Electrical and Computer Engineering, University of Wisconsin, Madison 53706, USA; (2)Research Institute of Electronic Science and Technology, University of Electronic Science and Technology of China, Chengdu 610054, China; (3)School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu 610054, China
Published: December 2020

Traveling wave tube (TWT) regenerative feedback oscillators have been demonstrated to be very attractive terahertz source devices. The principle and the physical model of this kind of device are analyzed. To see more detailed oscillation process, a 560 GHz folded waveguide TWT oscillator is presented. The results show steady-state oscillation frequencies exist between 550—600 GHz, and a single-frequency oscillation is found near 560 GHz. An oscillation frequency step-tuning behavior with the continuous variation of the beam voltage is discussed.
High-birefringence negative dispersion effect of novel rectangular lattice photonic crystal fiber
Authors: Zhang Ya-Ni  ,   Department of Physics and Information Technology, Baoji College of Arts and Science, Baoji 721007, China;State Key Laboratory of Transient Optics and Photonics, Xi’an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi’an 710119,
Published: December 2020

A novel rectangular lattice photonic crystal fiber is proposed which is composed of a central defect core and a cladding with square mesh structure by introducing another air hole row between two air hole rows for every other line into a conventional rectangular lattice photonic crystal fiber. Its dispersion, birefringence and confinement loss are numerically investigated by full vector finite element method with anisotropic perfectly matched layers. Numerical results indicate that the proposed fiber shows higher birefringence negative dispersion effect and stronger confinement ability of guided mode, in which the confinement loss is lower than 10-2 dB ·m-1. The wavelength for high birefringence negative dispersion can be optimized by adjusting the parameters of proposed fiber, such as Λ and d/Λ. The dispersion and the dispersion slope are both negative, the birefringence is higher than 10-2, and nonlinear parameter is close to 55 km-1W-1 over C band (i.e. 1.53—1.565 μm) under the condition of Λ=2.0 μm and d/Λ=0.4. This fiber will have important applications in the fields of polarization maintaining transmission system and dispersion compensation, and also in the design of widely tunable wavelength converter based on four-wave mixing.