bluuebunny/crossref_metadata_2025 huggingface dataset:
P-branch spectral lines of rovibrational transitions of CO molecule in ground state
Authors: Fan Qun-Chao  , Sun Wei-Guo  , Li Hui-Dong  , Feng Hao  ,   (1)Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, China; (2)School of Physics and Chemistry, Research Center for Advanced Computation, Xihua University, Chengdu 610039, China; (3)School of Physics and Chemistry, Research Center for Advanced Computation, Xihua University, Chengdu 610039, China; Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, China
Published: December 2020

An analytical formula is derived from elementary expression of molecular total energy for calculating the accurate P-branch spectral lines of rovibrational transitions for diatomic molecules. Using the constants (Bυ',Bυ″) and a group of fifteen known P-branch experimental transition lines for a transition band, the formula not only reproduces the known experimental transition lines, but also generates the spectral lines that may not be available experimentally. The P-branch emission spectra of the (2,0) band of the CO molecule are studied in this work, and correct values of the unknown spectral lines up to J = 80 for this band are predicted by using the formula.
A novel dual-band evolved split ring magnetic resonance metamaterial
Authors: Tang Ming-Chun  , Xiao Shao-Qiu  , Deng Tian-Wei  , Wang Duo  , Bai Yan-Ying  , Jin Da-Peng  , Wang Bing-Zhong  ,   Institute of Applied Physics, University of Electronic Science and Technology of China, Chengdu 610054, China
Published: December 2020

A novel dual-band evolved magnetic metamaterial operating at X-band is proposed in the paper, which is compounded by evolved split ring resonators based on the principle of magnetic resonance. The dual frequencies can be easily adjusted due to its excellent performance of weak mutual coupling between the outer ring and the inner ring. Our work provides the helpful research ideas and design methods for multiple-band and wideband metamaterials.
Feasibility study of nonlinear optical loop mirror in the cascaded stimwlated Brillouin scatteving-based slow light system
Authors: Zheng Di  , Pan Wei  ,   School of Information Science and Technology, Southwest Jiaotong University, Chengdu 610031, China
Published: December 2020

Based on the pulse compression characteristics in the nonlinear optical loop mirror (NOLM), the effect of NOLM on a cascad stimulated Brillouin scattering based slow light system is analyzed. In this paper, a ring structure is adopted to simulate the cascad system, so the complexity of system is reduced effectively, and the delay characteristics for various numbers of cycles and pump powers are studied. Analysis shows that the NOLM can effectively suppress the pulse-broadening in the cascaded slow light system, pump power determines the tendency and the final steady-state value of the broadening factor, and the broadening factor trends to the steady-state value after 4 cycles. Furthermore, zero-broadening can be obtained by optimizing the pump power; the delay time is continuously adjustable and without any limit in theory through changing the pump power and the number of cycles; through augmenting the pump power, the multiple-cascad-induced chirp can be reduced.
Midinfrared As2 S3 chalcogenide glass broadband normal dispersion photonic crystal fiber with high birefringence and high nonlinearity
Authors: Wang Xiao-Yan  , Li Shu-Guang  , Liu Shuo  , Zhang Lei  , Yin Guo-Bing  , Feng Rong-Pu  ,   Key Laboratory of Metastable Materials Science and Technology, College of Science, Yanshan University, Qinhuangdao 066004, China
Published: December 2020

A kind of midinfrared As2S3 chalcogenide glass photonic crystal fiber is proposed in this paper. The characteristics of this fiber are studied by multipole method, including high birefringence, chromatic dispersion, and high nonlinearity. Through numerical simulation, it is found that at midinfrared wavelength λ = 3.625 μm, the birefringence of this fiber reaches up to 0.098 and nonlinear parameters are 1.69 m-1 ·W-1 and 0.78 m-1 ·W-1 for x-polarized mode and y-polarized mode, respectively. In addition, the fiber keeps normal dispersion in a wavelength range from 3 to 7 μm . In conclusion, the band of transmitted wavelength extends into a midinfrared wavelength range of 3—10 μm, and high birefringence and high nonlinearity in this photonic crystal fiber are perfectly combined. The results are significant for the further development of new photonic devices.
Far field auto-alignment system used in SG-Ⅱ-Up system
Authors: Gao Yan-Qi  , Zhu Bao-Qiang  , Liu Dai-Zhong  , Peng Zeng-Yun  , Lin Zun-Qi  ,   Laboratory of High Power Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Shanghai 201800, China
Published: December 2020

The auto alignment system, which is used for the beam adjustment in high power laser system, is not only the key subsystem ensuring the routine operation effectually and safely, but also the key element involved in improving the far-field and near-field beam quality. Based on a skillful design of the grating and illumination-image system, a far field alignment system is realized. This system, which is based on a diffraction function of the grating, is characterized by the high performance and the simultaneous off-axis sample of the focus and the reference. The results, which are obtained when the system is used in pre-amplifier system of the SG-Ⅱ-Up, show that the reposition accuracy of the grating reference is better than 8μm, the jitter amplitude is less than 0.59 μm. After the alignment, the deviation of the beam focus from the grating reference is no more than 10 μm.
Effects of hydrogen flux on aluminum doped zinc thin films by pulsed magnetron sputtering
Authors: Li Lin-Na  , Chen Xin-Liang  , Wang Fei  , Sun Jian  , Zhang De-Kun  , Geng Xin-Hua  , Zhao Ying  ,   Institute of Photo-electronic Thin Film Devices and Technique of Nankai University, Key Laboratory of Photoelectronics Thin Film Devices and Technique of Tianjin, Key Laboratory of Optoelectronic Information Science and Technology of Ministry of Education
Published: December 2020

Aluminum doped zinc oxide (AZO) thin films are prepared by pulsed magnetron sputtering in pure argon gas. In order to improve the properties of AZO thin films, we add hydrogen gas into vacuum during sputtering. High purity ceramic ZnO ∶Al2O3 target and hydrogen gas at various flow rates are used as source materials. The microstructure, the surface information, the optical and electrical properties of AZO/H film are investigated. The crystallization, the Hall mobility and the transmission between 400 nm and 1100 nm are enhanced by increasing H2 flow rate, and resistivity is decreased, the lowest resistivities of these films are all 4.435×10-4 Ω·cm, and AZO thin films with 5.664×10-4 Ω·cm are achieved. In this experiment, it is observed that Raman peak is related to defects due to O-vacancies (579 cm-1) in the AZO/H thin films grown at different H2 flow rates. With the increase of hydrogen flow rate, the intensity of Raman peak at 579 cm-1 decreases. Finally, AZO and AZO/H thin films are etched in 0.5% dilute hydrochloric acid. Compared with AZO thin films, AZO/H thin films can be relatively easy to achieve the light trapping structure with crater-type morphology.
Positron annihilation spectroscopy study on the Fe3O4 nanoparticle
Authors: Xu Hong-Xia  , Hao Ying-Ping  , Han Rong-Dian  , Weng Hui-Min  , Du Huai-Jiang  , Ye Bang-Jiao  ,   Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China
Published: December 2020

The positron annihilation lifetime spectroscopy(PALS), coincidence doppler broadening spectroscopy(CDBS) and x-ray diffraction(XRD) are measured in the Fe3O4 . The aim is to ascertain how pressure and annealing temperature influence the properties of Fe3O4 nanoparticles, such as the change of phase, electronic structure, defect and distribution of electronic momenta. The results indicate that the defect concentration of Fe3O4 nanoparticles increases with the increase of pressure, but the phase and defect type do not change. The phase type, and the guantity and type of defect change significantly as the annealing temperature varies. The phase transition of the Fe3O4 wafer pressed in atmosphere occurs when the annealing temperature is between 350 ℃ and 500 ℃. The grain size of Fe3O4 increases with the increase of the annealing temperature, which leads to the decrease in boundary defect and parameter S but it is contrary to the ratio curve.
Effect of interface kinetics on the interface morphology of a spherical crystal in the undercooled melt
Authors: Chen Ming-Wen  , Ni Feng  , Wang Yan-Lin  , Wang Zi-Dong  , Xie Jian-Xin  ,   (1)Department of Materials Processing and Control Engineering, University of Science and Technology Beijing, Beijing 100083, China; (2)Department of Mathematics and Mechanics, University of Science and Technology Beijing, Beijing 100083, China; (3)Fangda Special Steel Technology Company Limited, Nanchang 330012, China
Published: December 2020

The change of the interface kinetic coefficient with the interface temperature under the non-equilibrium solidification condition is considered in the growth model of a spherical crystal. The first-order approximation solutions of temperature and interface for the spherical crystal growth in the undercooled melt are obtained by the asymptotic analysis method. The effects of the nonlinear interface kinetic undercooling on the interface morphology and the growth velocity of the spherical crystal in the undercooled melt are studied. The results show that as the interface kinetic coefficient increases, the growth velocity of the spherical crystal increases; as the interface kinetic coefficient decreases, the growth velocity of the spherical crystal decreases. Compared with the situation of neglecting interface kinetics, the nonlinear interface kinetics during crystal growth significantly decreases the growth velocity of the spherical crystal.
Nano-LiNiO2 as cathode material for lithium ion battery synthesized by molten salt method
Authors: Bai Ying  , Wang Bei  , Zhang Wei-Feng  ,   Key Laboratory of Photovoltaic Materials of Henan Province and School of Physics & Electronics, Henan University, Kaifeng 475004, China
Published: December 2020

Molten salt method is applied to synthesis stoichiometric nano-LiNiO2 in rather low temperature and short time. Our results indicate that in the process of preheating the better-crystallized LiNiO2 powder with better electrochemical performances can be produced. The final samples before and after preheating exhibit the initial discharge capacities of 151 and 148 mAh ·g-1 respectively. After 100 cycles, they decay to only 55 and 118 mAh ·g-1, with capacity retentions being 36.4% and 79.7% respectively. The lowered cation disordering is thought to be favorable for the diffusion of lithium ions, by which the enhanced electrochemial properties can be explained.
Optimization of slow wave structures of space traveling wave tube based on collectability of spent beam
Authors: Yi Hong-Xia  , Xiao Liu  , Liu Pu-Kun  , Hao Bao-Liang  , Li Fei  , Li Guo-Chao  ,   (1)Key Laboratory of High Power Microwave Sources and Technologies, Institute of Electronics, Chinese Academy of Sciences, Beijing 100190, China; (2)Key Laboratory of High Power Microwave Sources and Technologies, Institute of Electronics, Chinese Academy of Sciences, Beijing 100190, China; Graduate University of Chinese Academy of Sciences, Beijing 100190, China
Published: December 2020

A design method to enhance the efficiency of traveling wave tube is explored. The stair-step energy distribution of spent beam which is beneficial for the development of high collector efficiency depressed collector is obtained via the optimization of slow wave structures without degrading the basic electronic efficiency. A goal function expressed in the form of maximum collector efficiency of spent beam is designed to evaluate the collectability of spent beam. The optimization of slow wave structure based on collectability enhances the overall efficiency in the operation frequency band, and improves the small signal gain, but does not degrade nonlinear characteristic greatly compared with the simply optimization of slow wave structure based on electronic efficiency.
Deep levels of HgCdTe diodes on Si substrates
Authors: Zhang Shan  , Hu Xiao-Ning  ,   (1)Key Laboratory of Infrared Imaging Material and Detectors,Shanghai Institute of Technical Physics, Shanghai 200083, China; (2)Key Laboratory of Infrared Imaging Material and Detectors,Shanghai Institute of Technical Physics, Shanghai 200083, China; Graduated School of Chinese Academy of Sciences, Beijing 100049, China
Published: December 2020

The deep levels of the mid-wave infrared HgxCd1-xTe diodes(x=0.31), which are fabricated on Si substrates, are studied using the current-voltage-temperature (IVT) relationship. Firstly, the I-1/(kBT) relationship is fitted when the reverse current is dominated by generation-recombination process, and the deep level Eg/4 is calculated at the reverse bias 0.01 V. Secondly, the deep levels at different reverse biases are investigated. The origins of these deep levels correspond well to the reverse current mechanisms. Finally, the deep levels of different area diodes are calculated and compared. It is confirmed that the deep level is not related to diode area. This result is well corresponding to the theory, and indicates that the experimental method is correct.
Bifurcation and control of a class of inertial neuron networks
Authors: Zhao Hong-Yong  , Chen Ling  , Yu Xiao-Hong  ,   (1)College of Jingling Science and Technology, Nanjing 211169, China; (2)School of Science, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
Published: December 2020

The paper deals with the stability and the bifurcation of a class of inertial neural networks. Based on sensitivity theory, we determine the suitable bifurcation parameter. Using Routh-Hurwitz criterion and bifurcation theory, we give some new criteria for stability,Hopf bifurcation and steady state bifurcation. Numerieal simulations are given to validate the theoretieal analysis showing that the delayed feedback controller can control the occurrence of bifurcation effectively and the amplitude of the bifurcated limit cycle as well.
Infinite sequence peak solitary wave solutions ofDegasperis-Procesi equation
Authors: Taogetusang  ,   College of Mathematical Science, Inner Mongolia Normal University, Huhhot 010022, China
Published: December 2020

To construct infinite sequence peak solitary wave solutions to nonlinear evolution equations, Bäcklund transformation of Riccati equation and nonlinear superposition formula of the solutions are introduced, then Degasperis-Procesi equation is taken as an example and infinite sequence peak solitary wave solutions and periodic solutions of the equation are obtained with the help of symbolic computation system Mathematica.
Parameter estimate from coupled map lattices based on symbolic vector dynamics
Authors: Wang Kai  , Pei Wen-Jiang  , Zhang Yi-Feng  , Zhou Si-Yuan  , Shao Shuo  ,   Department of Radio Engineering, Southeast University, Key Laboratory of Underwater Acoustic Signal Processing of Ministry of Education, Southeast University,Nanjing 210096, China
Published: December 2020

Symbolic dynamics, which partitions the infinite number of finite length trajectories into a finite number of trajectory sets, allows a simplified and "coarse-grained" description of the dynamics of a system with a limited number of symbols. In this paper, we further develop the symbolic vector dynamical estimation method in coupled map lattice (CML). We take the CML of Logistic map as an example, to show that the control parameters affect the dynamical characters of symbolic vector sequence. We study the ergodic property of CML by using the inverse function of CML. We give the symbolic vector dynamical description of the initial values, the forbidden words and the control parameters for studying pattern formation in CML. We also give a coupling coefficient estimation approach based on the ergodic property.
Security of chaos-based secure communications in a large community
Authors: Wang Kai  , Pei Wen-Jiang  , Zhou Jian-Tao  , Zhang Yi-Feng  , Zhou Si-Yuan  ,   Department of Radio Engineering, Southeast University, Key Laboratory of Underwater Acoustic Signal Processing of Ministry of Education, Southeast University, Nanjing 210096, China
Published: December 2020

In this paper, we present an attack on a cryptosystem designed by using a spatiotemporal chaotic system. We show that the decryption system proposed in (Phys. Rev. E 66, 065202 (2002)) degenerates to the one-dimensional map under the constant input, and it is insensitive to the slight perturbations to input in specially selected intervals. Consequently, the attacker can use a very simple optimization algorithm to obtain the proper input value within only hundreds of iterations. Furthermore, we prove that there exits a linear dependency between the secret key and the obtained input value, so that the attacker can break this spatiotemporal chaos-based secure communication scheme easily. Both theoretical and experimental results show that the lack of security discourages the use of these cryptosystems for practical application.
Design and analysis of a polarization interference imaging spectrometer with expanded field of view
Authors: Mu Ting-Kui  , Zhang Chun-Min  , Ren Wen-Yi  , Zhang Lin  , Zhu Bao-Hui  ,   MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, School of Science, Xi'an Jiaotong University, Xi'an 710049, China
Published: December 2020

To obtain straight interference fringes over larger field of view and thus acquire high-accuracy interference data, a wide field of view polarization interference imaging spectrometer based on a combined Savart plate is presented. The Savart plate is composed of positive and negative uniaxial crystals. The relationship between the optical path difference and incident angle is given. By numerical modeling and analysis examples with similar spectral resolution and total thickness, The simulation results show that the field of view to obtain straight interference fringes for the combined Savat plate is ten times as large as that for the conventional Savart plate.
Density functional study of interation of Hg with small gold clusters
Authors: Sun Lu-Shi  , Zhang An-Chao  , Xiang Jun  , Guo Pei-Hong  , Liu Zhi-Chao  , Su Sheng  ,   (1)School of Mechanical and Power Enginneering, Henan Polytechnic University, Jiaozuo 454003, China; (2)State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, Wuhan 430074, China; (3)State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, Wuhan 430074, China;School of Mechanical and Power Enginneering, Henan Polytechnic University, Jiaozuo 454003, China
Published: December 2020

Elemental mercury (Hg) adsorptions on small neutral, cationic and anionic gold clusters, Auqn (n=1—6, q=0, +1, -1), are systematically investigated by using the density functional theory(DFT) in the generalized gradient approximation. The result shows that the frontier molecular orbital theory (FMOT) is useful for predicting the favorable binding configurations of Hg adsorbed on neutral and charged Aun clusters. Most of the lowest energy AunHg complexes can be successfully predicted. The size and the charge state of the clusters have strong influence on the adsorption of Hg on gold clusters. The adsorption energy on the neutral clusters reaches a local maximum at n=4, which is about 0.661eV. The adsorption energies for cationic clusters decrease with cluster size increasing, although there is a local peak at n=5. Similarly, for anionic clusters, the adsorption energies decrease with cluster size, except for n=3. The adsorption energies on the cationic clusters are generally stronger than those on the neutral and anionic clusters. For the lowest energy AunHg complexes, an approximate linear correlation between the adsorption energy and the Mulliken charge on adsorbed Hg is found. The more the charges transfer to the cluster, the higher the adsorption energy is.
Tunable composite absorber with active frequency selective surface
Authors: Chen Qian  , Jiang Jian-Jun  , Bie Shao-Wei  , Wang Peng  , Liu Peng  , Xu Xin-Xin  ,   Department of Electronic Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
Published: December 2020

Based on the equivalent transmission line theory, a three-layer tunable composite absorber with active frequency selective surface (AFSS) is designed. The first layer is an AFSS substrate. The middle layer is an AFSS, which is composed of a frequency selective surface (FSS) and a PIN diode array. The third layer is an insulator. Reflectance measurement shows that the reflection characteristic of the absorber can be dynamically adjusted by adjusting the bias voltage of the PIN diode array. When the bias voltage is 5 V, the best absorption property is observed. Reflection coefficient is below -8 dB and -10 dB at the frequency bands of 5—15 GHz and 5.3—13 GHz, respectively. Replacing PIN diodes with surface mount device (SMD) resistors, the reliability of the above results is further verified.
Theoretical study of polarization atmosphere Michelsoninterferometer using multi-wavelength
Authors: Zhu Hua-Chun  , Zhang Chun-Min  ,   School of Science, Xi'an Jiaotong University, Non-equilibrium Condensed Matter andQuantum Engineering Laboratory, the Key Laboratory of Ministry of Education, Xi'an 710049, China
Published: December 2020

The basic principle of measuring the upper atmosphere using the polarization atmosphere Michelson interferometer (PAMI) is briefly described. The relationships between the intensity and the visibility of the PAMI and the Delayed phase of the wave plate are presented. The visibility and the intensity of the PAMI are dependent on the wavelength of spectral line, showing that the 732nm line is inapplicable for measuring spectral line if the PAMI is designed specifically for the 630 nm line. The research provides a theoretical basis and practical guidance both for the theoretical study of polarization atmosphere Michelson interferometer and for the design and development of the new polarization atmosphere Michelson interferometer.
Analytical model for the tuning characteristics of static, dynamic, and transient behaviors in temperature and injection current of DFB laser diodes
Authors: Liu Jing-Wang  , Du Zhen-Hui  , Li Jin-Yi  , Qi Ru-Bin  , Xu Ke-Xin  ,   (1)State Key Laboratory of Precision Measuring Technology and Instruments, Tianjin University, Tianjin 300072, China; (2)State Key Laboratory of Precision Measuring Technology and Instruments, Tianjin University, Tianjin 300072, China;North China Institute of Aerospace Engineering, Langfang 065000, China
Published: December 2020

From the tuning mechanism of the DFB laser diode, we establish an analytical model for current and temperature tuning characteristics. The parameters of the model are identified by experimental results. The model is used to analyze the four DFB diode lasers, and the transient characteristics of the lasers are obtained. We also obtain the static characteristics of these lasers from Agilent 86142B Spectrometer. The comparison between the two values indicates that the correlation coefficients are both more than 0.9999. At the same time, according to the absorption spectrum of CO2 gas, we also measure the emission wavelength of lasers. Comparing it with the HITRAN spectrum of CO2 absorption lines, the two errors are shown to be within 3pm. The analytical model can accurately predict the transient output wavelength of lasers in tuning, the accuracy can meet the spectrum, optical coherence measurements and other practical requirements.
Double-channel narrowband filter based on Goos-Hänchen shift
Authors: Hao Jun  , Li Hong-Gen  , Cao Zhuang-Qi  , Chen Fan  ,   (1)Department of Physics, the State Key Laboratory on Fiber Optic Local Area Communication Networks and AdvancedOptical Communication Systems, Shanghai Jiaotong University, Shanghai 200240, China; (2)Finisar Shanghai Incorporation, Shanghai 201201, China;Department of Physics, the State Key Laboratory on Fiber Optic Local Area Communication Networks and AdvancedOptical Communication Systems, Shanghai Jiaotong University, Shanghai 200240, China
Published: December 2020

We propose a double-channel narrowband filter based on anomalous large Goos-Hänchen shift reflected from a symmetrical metal-cladding optical waveguide. We demonstrate that two filtering peaks are 859.604nm and 859.688nm respectively. The 3 dB bandwidth is found to be 0.036 nm with an extinction ratio of 15.3dB at a light wavelength of 859.60nm. The filtering peaks can be tuned by choosing an appropriate incident angle and a aperture position.
Mechanism of optical stopping effect of arsenicsulfide amorphous waveguide
Authors: Wang Guan-De  , Chen Bao-Xue  , Wang Ping  , Sui Guo-Rong  , Mamoru Iso  , Hiromi Hamanaka  , Zou Lin-Er  ,   (1)Department of Chemical Engineering, Tokyo University of Agriculture and Technology, Tokyo 184-8588, Japan; (2)Department of Physics, Nanchang University, Nanchang 330031, China; (3)Faculty of Engineering, Hosei University, Tokyo 184-8584, Japan; (4)School of Optical-Electrical and Computer Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
Published: December 2020

In this paper, the optical stopping effect of thin film waveguide with doping As2S8 and As2S8 is studied. Based on this, the mechanisms of formation and transfer of abnormal electron configuration are discussed, and the dynamic models of optical stopping and reversion process are proposed. The numerical analysis results are in good agreement with the experimental data, so the phenomenon in experiment can be predicted by this model, which implies that this model holds the basic features and the essence of the optical stopping effect.
Physical simulation of homogeneous Zn-Bi monotectic alloy prepared by electric-magnet compound field
Authors: Wang Jiang  , Zhong Yun-Bo  , Wang Chao  , Wang Zhi-Qiang  , Ren Zhong-Ming  , Xu Kuang-Di  ,   Shanghai Key Laboratory of Modern Metallurgy & Material Processing, Shanghai University, Shanghai, 200072, China
Published: December 2020

Through physical simulation, we study the influence mechanism of electromagnetic field on the solidification structure of homogeneous Zn-Bi monotectic alloy, the transformation rule of the diameter of molten secondary phase under the compound field, and the process of the shattering of the layered structure into matrix by the Lorentz force. The results show that the diameter of the secondary drop decreases with AC current density and magnetic field increasing. The influence of AC frequency has an optimal value from which the deviation can weaken the suppression of diameter, which accords with the experimental result. The layered metal liquid can be uniformly mixed under the action of electromagnetio field. The above effects can effectively release segregation of the second phase of monotectic alloy. The simulation results show the main factors of preparing the homogeneous monotectic alloy in an electromagnetic field intuitively.
Investigation of Ge quantum dots formation on SiO2 substratethrough annealing process
Authors: Zhang Lei  , Ye Hui  , Huangfu You-Rui  , Liu Xu  ,   State Key Laboratory of Modern Optical Instrumentation, Zhejiang University, Hangzhou 310027, China
Published: December 2020

Ge is deposited on an ultrathin SiO2 layer obtained chemically at room temperature, followed by annealing process. High density and uniform Ge quantum dots, rather than superdomes in traditional treatment, are obtained. Growth mechanism is suggested to explain the unusual microstructure dependence on annealing temperature. Raman spectrum is used to investigate the strain. Two peaks are found to be around 500 nm and 1350 nm respectively from the photoluminescence characterization.
Growth and device characteristics of nano-folding InGaN/GaNmultiple quantum well LED
Authors: Chen Gui-Feng  , Tan Xiao-Dong  , Wan Wei-Tian  , Shen Jun  , Hao Qiu-Yan  , Tang Cheng-Chun  , Zhu Jian-Jun  , Liu Zong-Shun  , Zhao De-Gang  , Zhang Shu-Ming  ,   (1)Key Lab. for New Type of Functional Materials in Hebei Province, Hebei University of Technology, Tianjing 300130, China; (2)State Key Laboratory of Integrated Optoelectronics, Institute of Semiconductors, Chinese Academyof Sciences, Beijing 100083, China; (3)Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China
Published: December 2020

GaN-based LED wafers with nano-folding InGaN/GaN multiple quantum wells (MQWs) are grown on n-GaN nanopillar array templates which are fabricated using self assembled Ni nanodots as etching mask. Photoluminescence (PL) spectra of the wafer show uniform light emission wavelength over the whole area of it. No blue shift of the main peak is observed in the electroluminescence (EL) spectra of the LED devices fabricated with the wafer as the injection current increases from 10 mA to 80 mA. This can be ascribed to the reduced quantum confinement Stark effect (QCSE) and the resulting less band gap tilted by strain relaxation in the nano-folded MQWs. The device shows an excellent rectifying behavior with a forward voltage of 4.6 V under 20 mA injection current.
Two-dimensional threshold voltage model of sub-100 nm strained-Si/SiGe nMOSFET
Authors: Wang Guan-Yu  , Zhang He-Ming  , Wang Xiao-Yan  , Wu Tie-Feng  , Wang Bin  ,   Key Laboratory for Wide Band-Gap Semiconductor Materials and Devices,School of Microelectronics, Xidian University,Xi'an 710071,China
Published: December 2020

In this paper, based on the two-dimensional (2D) Possion's equation, an analytical model of threshold voltage, which is applied to a sub-100nm strained-Si/SiGe nMOSFET, is pro- posed. The secondary effects induced by reducing size such as short-channel effects, quantum mechanical effects are also taken into consideration in order to ensure the accuracy of the model. Then the evidence for the validity of our model is derived from the comparison between analytical results and the simulation data from the 2D device simulator ISE. Finally, the influence of conventional arts in sub-100 nm device fabrication on threshold voltage is also discussed. The proposed model can also be easily used for reasonable analysis and design of sub-100nm strained-Si/SiGe nMOSFET.
Electron mobility of strained Si/(001)Si1- x Ge x
Authors: Wang Xiao-Yan  , Zhang He-Ming  , Song Jian-Jun  , Ma Jian-Li  , Wang Guan-Yu  , An Jiu-Hua  ,   (1)Key Laboratory for Wide Band-Gap Semiconductor Materials and Devices, School of Microelectronics, Xidian University, Xi'an 710071, China; (2)Key Laboratory for Wide Band-Gap Semiconductor Materials and Devices, School of Microelectronics, Xidian University, Xi'an 710071, China;Department of Electron and Electricity Engineering, Baoji University of Arts and Sciences, Baoji 721007, China
Published: December 2020

According to the model of ionized impurity scattering, acoustic phonon intravalley scattering and optical phonon intervalley scattering, the dependences of electron mobility of strained Si/(001)Si1-xGex with different germanium constituents on impurity concentration are studied based on Subband occupation by solving Boltzmann equation. The results show that electrons almost totally occupy the Δ2 valley when germanium constituent is up to 0.2, and the mobility with germanium constituent 0.4 is 64% higher than that of the unstrained silicon at low impurity concentration; and vertical channel is not so good for tensile stained Si devices. The model can also be used to calculate the electron mobility of other crystal face with an arbitrarily orientation if the parameters are correctly chosen, so the model offers some useful foundation for strained silicon devices and circuits.
Structural stability and field emission propertiesof cone-capped carbon nanotubes
Authors: Wang Yi-Jun  , Wang Liu-Ding  , Yang Min  , Yan Cheng  , Wang Xiao-Dong  , Xi Cai-Ping  , Li Zhao-Ning  ,   School of Science, Northwestern Polytechnical University, Xi'an 710129, China
Published: December 2020

The structural stability and the electronic field emission properties of cone-capped carbon nanotubes have been deeply analyzed by the density functional theory. The results show that their structurs are much more stable than those of carbon nanocones and carbon nanotubes sealed with a C30 hemisphere, and their electronic field emission properties are closely related to the configuration of cone apex and the magnitude of cone angle. Meanwhile, the combination property of cone1@(6,6) with a ridge-shaped tip and 38.9° cone angle is optimal. When it is used as a field emission source the field emission current density and the lifetime of device will be remarkably increased.
Effect of assembled bar magnet configuration on levitation force of single domain GdBCO bulk superconductor
Authors: Ma Jun  , Yang Wan-Min  ,   (1)College of Physics and Information Technology, Shaanxi Normal University, Xi'an 710062, China; (2)College of Physics and Information Technology, Shaanxi Normal University, Xi'an 710062, China;Department of Physics Qing hai Normal University, Xi ning 810008, China
Published: December 2020

By measuring the levitation forces between a single domain GdBCO bulk superconductor and assembled bar magnets(ABM) in different configurations at liquid nitrogen temperature, the effects of ABM configurations on the levitation force of single domain GdBCO bulk superconductor are investigated. The maximum levitation force is obtained at the same vertical gap distance Z=5 mm between the superconductor and the ABM for configurations with different lateral gap distance(D)between the magnets of the ABM. It is found that 1) for the ABM consisting of 3 bar magnet, the levitation force of the GdBCO bulk decreases from 22.8N to 9.7N with the D value increasing from 0 to 30 mm, when the magnetic pole N of the middle magnet is pointed upwards and the directions of magnetic pole N of two side magnets are pointed to the middle magnet in horizontal direction; the levitation force of the GdBCO bulk increases first from 9.2N to 13.9N and then decreases to10.4 N with D value increasing from 0 to 30mm, if the magnetic pole N of the middle magnet is pointed upwards and the directions of magnetic pole N of two side magnets are pointed downwards;2)for the ABM consisting of 2 bar magnets, the levitation force of the GdBCO bulk decreases from 11.2N to 1.2N with D value increasing from 0 to 30mm, when the directions of magnetic pole N of two side magnets are pointed upwards; the levitation force of the GdBCO bulk increases first from 6.0N to 6.8N and then decreases to 2.9N with D value increasing from 0 to 30mm, if the directions of magnetic pole N of two magnets are anti-parallel in horizontal direction; 3)for the ABM consisting of only 1 bar magnets, D≡0, and the levitation force of the GdBCO bulk is about 9.5N. The results indicate that the magnet configuration and its detailed parameters of ABM are very important for improving the levitation force of a superconductor and helpful for designing and application based on the superconducting magnetic levitation system.
Effects of grain size and substrate stress of ferroelectric film on the physical properties
Authors: Wang Ying-Long  , Zhang Peng-Cheng  , Liu Hong-Rang  , Liu Bao-Ting  , Fu Guang-Sheng  ,   College of Physics Science and Technology, Hebei University, Baoding 071002, China
Published: December 2020

A modified Landau-Devonshire thermodynamic model is presented, with the contributions of substrate stress, domain wall motion and domain structure transition taken into account. The hysteresis loops of PbZr0.4Ti0.6O3(PZT) films, which are deposited on different substrates, containing nano-scale grain is calculated, and the thickness and grain size dependences of coercive field, remnant polarization and relative permittivity are researched. The results demonstrate that the grain size is dependent on coercive field and relative permittivity as shown in paraboliclike curve, that the pressure stress of substrate enhances the coercive field and remnant polarization, but reduces the relative permittivity, and that the coercive field increases slowly first with the thickness of film, then increases sharply between 200 nm and 310 nm of the thickness, and slowly again after 310 nm. This result is due to the thickness dependence of relative permittivity.
Influence of improved anti-Stokes energy transfer between rare earth ions in ErP5O14 noncrystal on dynamic study
Authors: Chen Ying  , Chen Xiao-Bo  , Zhang Hui-Min  , Xu Xiao-Ling  , Wang Ce  ,   Applied Optics Beijing Area Major Laboratory, Analytical and Testing Center, Beijing Normal University, Beijing 100875, China
Published: December 2020

Since the visible quantum cutting in Eu3+–Gd3+ material was reported, the importance, the application, and the significance of the quantum cutting phenomenon have been widely recognized.The rate equations which describe the luminescence dynamic processes for different concentrations of (ErxLa1-xP5O14) noncrystal are established in this paper. The coefficients exp{hc k/kT} is introduced in to the calculation of anti-Stokes energy transfer rate to distinguish Stokes energy transfer.All dynamic processes have been simulated separately with and without considering this coefficient for the energy transfer rate of Er0.01La0.99P5O14,Er0.1La0.9P5O14 and ErP5O14 noncrystals when their 2H11/2 ,4I9/2 and4I11/2 levels are excited.The results show that it is essential to take the coefficient into calculation particularly for ErP5O14 noncrystal where energy transfer plays a key role.There is no influence though the distance between rare earth ions is larger.And it is found that infrared quantum cutting exsists in ErP5O14 noncrystal excited by visible light. The relative nonradiative relaxation rate, the spontaneous emission rate and the energy transfer rate are calculated particularly , The relative energy transfer dynamics is analyzed.It is found that the {4H11/2→4I9/2,4I15/2→4I13/2} energy transfer with a rate of 239500s-1, is the main reason for 2H11/2 energy level to have the infrared quantum cutting, Which is meaningful for finding high-efficiency solar cell materials.
Investigation on photocurrent of ZnPc/C60 solar cells
Authors: Wu Jia-Qi  , Li Wen-Jia  , Meng Qing-Lei  , Ji Jing-Jia  , Xi Xi  , Gu Xiao-Feng  , Li Guo-Hua  ,   (1)School of Science, Jiangnan University, Wuxi 214122, China;Jiangsu (Suntech) Institute for Photovoltaic Technology, Wuxi 214028, China; (2)School of Science, Jiangnan University, Wuxi 214122, China;Suntech Power Co., Ltd., Wuxi 214028, China; (3)School of the Internet of Things, Jiangnan University, Wuxi 214122, China; (4)Suntech Power Co., Ltd., Wuxi 214028, China;Jiangsu (Suntech) Institute for Photovoltaic Technology, Wuxi 214028, China; (5)Suntech Power Co., Ltd., Wuxi 214028, China;Schoo
Published: December 2020

Solar cells with structure of ZnPc (20 nm)/C60 (10 nm) are fabricated by thermal evaporation. The photocurrent density (Jph) expressed by effective applied voltage (V0-Va) and light intensity (I) is derived from an analytical method, and it is shown that the results from the model are in good agreement with experimental results. The short-circuit current density (JSC) exhibits a nearly linear dependence on light intensity, which is partially determined by effective applied voltage. Thermal annealing treatment under an optimal condition of 100 ℃ and 20 min, improves JSC by 43.8%, lengthening its attenuation constant from 5.6h to 22.2 h, which is attributed to the improvement on interfacial morphology and the decrease of series resistance due to better contact of the layers.
A new global embedding approach to study Hawking and Unruh effects for higher-dimensional rotation black holes
Authors: Zhang Li-Chun  , Li Huai-Fan  , Zhao Ren  ,   Institute of Theoretical Physics, Department of Physics, Shanxi Datong University, Datong 037009, China
Published: December 2020

First, we effectively reduce the higher-dimensional rotation metric to a 2-dimensional metric near the event horizon which contains only the (t-r) sector. Then, we study the Unruh/Hawking temperature for (1+1)-dimensional space-time with the new global embedding method. It is shown that the viewpoint of Banerjee and Majhi is correct. We also extend the study to the case of higher-dimensional rotation black hole.
Control of spiral waves in FitzHugh-Nagumo systems
Authors: Gao Jia-Zhen  , Xie Ling-Ling  , Xie Wei-Miao  , Gao Ji-Hua  ,   Key Laboratory of Special Functional Materials of Shenzhen, College of Materials, Shenzhen University, Shenzhen 518060, China
Published: December 2020

Control of spiral wave in two-dimensional FitzHugh-Nagumo equation is studied. The phase space compression approach is used to confine the system trajectory into a finite area and to annihilate spiral wave in the numerical simulation. Three stages are found in the control process. The spiral is driven to a homogenous stationary state when the compress limit is small; the spiral is stable with a fixed frequency when the compression limit is large; in the intermediate controlling parameter regime, the spatiotemporal turbulent state is observed. The controlling process is investigated by considering system pattern, variable evolution, phase space trajectory, etc, and the characteristics of amplitude function and oscillatory frequency are summarized as well.
Ti:sapphire femtosecond comb with two spectral broadening parts
Authors: Cao Shi-Ying  , Fang Zhan-Jun  , Meng Fei  , Wang Qiang  , Li Tian-Chu  ,   Division of Electricity and Quantum Metrology, National Institute of Metrology, Beijing 100013, China
Published: December 2020

The first generation of femtosecond optical frequency comb (FOFC) based on the Ti:sapphire femtosecond laser in National Institute of Metrology of China, is improved and optimized in this paper. By changing the repetition rate of the femtosecond laser, the spectral broadening parts and the beat frequency signal detection, the complexity of spectral broadening is reduced and the stability of FOFC and the convenience for the frequency measurement are improved. With such an FOFC, the absolute frequencies of the I2-stabilized Nd:YAG 532 nm laser and I2-stabilized He-Ne 633 nm laser are measured. The experimenal results are in accordance with the recommended values by the International Committee for Weights and Measures.
X-ray Zernike apodized photon sieves for phase-contrast microscopy
Authors: Cheng Guan-Xiao  , Hu Chao  ,   Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China; Department of Electronic Engineering, The Chinese University of Hong Kong, Hong Kong, China
Published: December 2020

We present a kind of diffractive lens Zernike apodized photon sieves (ZAPS) whose structure is based on the combination of two concepts: apodized photon sieves and Zernike phase-contrast. Combined with the synchrotron light source, the ZAPS can be used as an objective for high-resolution phase-contrast X-ray microscopy in physical and life sciences. The ZAPS is a single optic unit that integrates the appropriate /2 radians phase shift through selective zone placement shifts in an apodized photon sieve. The focusing properties of the ZAPS can be easily controlled by apodizing its pupil function. An apodized photon sieve with Gaussian pupil is fabricated by lithographic technique and shows that the side-lobes are significantly suppressed at the expense of slightly widening the width of the main lobe.
Cross sections of Cq+(q=14)electron loss in collision with He, Ne and Ar investigating
Authors: Lu Yan-Xia  , Xie An-Ping  , Li Xiao-Hua  , Xiang Dong  , Lu Xing-Qiang  , Li Xin-Xia  , Huang Qian-Hong  ,   School of Nuclear Science and Technology, University of South China, Hengyang 421001, China
Published: December 2020

Electron-loss cross sections in Cq+(q=14)collisions with He,Ne,Ar are measured in the intermediate-velocity regime, and the ratio of the two-electron-loss cross section to the one-electrom-loss cross section, R21, are calculated. It is shown that a single-channel analysis is not sufficient to explain the results, and that projectile electron loss, electron capture by the projectile, and target ionization must be considered together to interpreter the data. The screening and antiscreening theory can annalyse the threshold velocity, but cannot totally explain the data of R21 with velocity increasing. The effective charge of target increases with velocity increasing. Ne and Ar have the same effective charges in the velocity regime, but He has a smaller one at the same velocity. The correlation between loss electrons is also analyzed.
A mircostrip antenna with single square ring structured left-handed metamaterial
Authors: Guo Lin-Yan  , Yang He-Lin  , Li Min-Hua  , Gao Chao-Song  , Tian Yuan  ,   College of Physical Science and Technology, Central China Normal University, Wuhan 430079, China
Published: December 2020

A simple structured left-handed metamaterials composed of single square ring cell is fabricated. Its permittivity and permeability are simultaneously negative in 4.8-5.25 GHz. A 5.0 GHz microstrip antenna is proposed, and we use this single square ring structured left-handed metamaterials (SSR-LHMs) as covering layer. Simulation and experiment results show that compared with conventional microstrip antenna, the performance of the new microstrip antenna with SSR-LHMs has been improved remarkably. The -3 dB beam of E-plane and H-plane can be reduced respectively by 25 and 20, so the directional property of the antenna is enhanced. The gain is improved by 3dB and the -10 dB bandwidth is increased by 600 MHz.
All-optical format conversion from non-return-to-zero to return-to-zero based on four-wave mixing in photonic crystal fiber
Authors: Hui Zhan-Qiang  , Zhang Jian-Guo  ,   Xi'an Institute of Posts and Telecommunications, Xi'an 710061, China;,   State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China
Published: December 2020

The conversion from all-optical non-return-to-zero (NRZ) to return-to-zero (RZ) format is a crucial technology in interfacing WDM and OTDM of future transparent photonic network. The conversion from all-optical single-to-dual NRZ to RZ format conversion is presented and experimentally demonstrated based on four-wave mixing (FWM) in a 50 m dispersion-flattened highly-nonlinear photon crystal fiber (DF-HNL-PCF). The original NRZ format is converted into RZ format by injecting synchronized clock signal into the DF-HNL-PCF. The FWM effect generates two sideband components, which carry the same data information as the original NRZ signal with RZ format. The proposed format converter has a wide and tunable operation wavelength range of 19.3 nm. The optimum conversion efficiency, extinct ratio and Q factor are -21 dB, 11.9 dB and 7.2, respectively. The system is transparent to both bit rate and modulation format. The advantage of this scheme consists in the ability of bandwidth scalable due to the fact that the dispersion flattening of HNL - PCF is used. Furthermore, it is all optical fiber, compact and robust, which makes it more competitive as well as easily accessible for use in practical optical communication systems.