bluuebunny/crossref_metadata_2025 huggingface dataset:
Unbiased solid surface charging research inplasma environment
Authors: Cao He-Fei  , Liu Shang-He  , Sun Yong-Wei  , Yuan Qing-Yun  ,   Electrostatic & Electromagnetic Protection Institute, Ordnance Engineering College, Shijiazhuang 050003, China;,   Department of physics, Shijiazhuang College, Shijiazhuang 050035, China
Published: December 2020

Within the plasma environment of spacecraft, the interaction between electrons and ions may cause surface charging and discharging and may degrade the performance of spacecraft. The charging potential is a key factor for discharging process. By considering the comprehensive effects of particle mass, temperature, density of plasma, secondary electrons and the velocity of unbiased solid, a general equation of surface charging potential of unbiased solid has been derived using Maxwell velocity distribution function. The expressions under some special and general conditions have been also analyzed. The surface charging and discharging properties are summarized under different plasma environment and motion states of unbiased solid.
Chaotic transients and generalized crises of a Duffing-van der Pol oscillator with two external periodic excitations
Authors: Han Qun  , Xu Wei  , Liu Tao  , Liu Li  ,   Department of Applied Mathematics, Northwestern Polytechnical University, Xi’an 710129, China
Published: December 2020

Global property of a Duffing-van der Pol oscillator with two external periodic excitations is investigated by generalized cell mapping digraph method. As the bifurcation parameter varies, a chaotic transient appears in a regular boundary crisis. Two kinds of transient boundary crises are discovered to reveal some reasons for the discontinuous changes for domains of attraction and boundaries. A chaotic saddle collides with the stable manifold of a periodic saddle at the fractal boundary of domains when the crisis occurs, if the chaotic saddle lies in the basin of attraction, the basin of attraction decreases suddenly while the boundary increases after the crisis; if the chaotic saddle is at a boundary, the two boundaries merge into one because of the crisis. In addition, two chaotic saddles can be merged into a new one, when they touch each other in a transient merging crisis. Finally the chaotic transient disappears in an interior crisis. The characteristics of these generalized crises are quite important for the study of chaotic transients.
Design and experimental demonstration of high-efficiency double-helix point spread function phase plate
Authors: Li Heng  , Yu Bin  , Chen Dan-Ni  , Niu Han-Ben  ,   Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering,Shenzhen University, Shenzhen 518060, China
Published: December 2020

Double helix point spread function possesses continuously rotating invariant features with defocus, and it can be used for performing nano-resolution image of thick samples and for studying singleparticle tracking by combining the single-molecule localization method. However, the inadequacy of the original double helix point spread function is that the transfer function efficiency is very low, so it is difficult to achieve photon limited applications for the bio-imaging. The double-helix point spread function is optimized by introducing an iterative algorithm so that the constraints of the point spread function can be optimized best in three different domains: the Laguerre-Gauss modal plane, the spatial domain, and the Fourier domain. The simulation results show that the peak intensity of high efficiency double helix point spread function is 30 times higher than the original one. The design and fabrication of the phase plate are also proposed. The experimental results are in good agreement with the theoretical predictions, thus proving the feasibility of this method.
Analytical bond-order potential for Sn
Authors: An Rong  , Liu Wei  , Wang Chun-Qing  , Tian Yan-Hong  ,   Key Laboratory of Micro-Systems and Micro-Structures Manufacturing, Ministry of Education, Harbin Institute of Technology, Harbin 150080, China;,   State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001, China
Published: December 2020

An analytical bond-order potential based on Tersoff-Brenner model for Sn is developed using the Levenberg-Marquardt optimization algorithm with the first-principles calculations on fundamental physical properties of five configurations of Sn, and with the available experimental results. The potential is used to determine the crystal structures, binding energies, bond distances and strengths, and bulk modulus of the β-Sn and body-centered-tetragonal Sn, and to predict the changes in free energy of the α and β phase with temperature. Result indicate that the calculated basic properties of the phases and the predicted transition temperature from α to β phase are in good agreement with the reported experimental data. The proposed interatomic potential is short-ranged and quickly evaluated, and it could be used to distinguish covalent bond from metallic bond in the phases, so it is very useful for large-scale molecular dynamics simulations of Sn-based solder.
Self-trapping and periodic modulation of Fermi gases in optical lattices
Authors: Gou Xue-Qiang  , Yan Ming  , Ling Wei-Dong  , Zhao Hong-Yu  , Duan Wen-Shan  ,   College of Physics and Electronic Engineering, Northwest Normal University, Lanzhou 730070, China
Published: December 2020

The change of phase space and periodic modulation of Fermi gas from the BCS to unitarity is investigated in one-dimensional optical lattice. Through controlling the scattering length and coupling constant in unitarity, we find the critical values (from the Josephson oscillation to the oscillating-phase-type self-trapping and from the latter to the self-trapping), at the same time, we also find the relationship between the critical coupling constants and the scattering length.
Investigation of the ultrafast phase evolution of the ejected material generated during femtosecond laser ablation of aluminum by the coherent light illuminated schlieren apparatus
Authors: Yang Jing-Hui  , Zhang Nan  , Zhu Xiao-Nong  ,   Institute of Modern Optics, Nankai University, Key Laboratory of Optical Information Science and Technology, Ministry of Education, Tianjin 300071, China;,   Basic Course Teaching Department, Chinese People's Armed Police Forces Academy, Langfang 065000, China
Published: December 2020

A novel phase measurement method based on the schlieren apparatus is proposed, and the ultrafast phase evolution of the ejected material generated during the femtosecond laser ablation of aluminum is experimentally studied by this method. Different from the conventional schlieren technique, the phase measurement method presented in this work uses coherent light as the illuminating light. The specimen's phase under-test is derived with the help of the interference between the light which irradiates the surroundings of the specimen and the light which transmits through the specimen and diffracts on the razor edge of the schlieren apparatus. One remarkable merit of this method is that it can clearly exhibit the specimen's phase variation of mπ or 2mπ (m is an integer). The ultrafast process of the ejected material generated during the 5.4 J/cm2, 50 fs laser pulses ablation of the aluminum target is investigated by this novel phase measurement method and the pump-probe technique. Results show that the ejected material is composed of three sequentially appearing regions with different phase evolving processes, which are respectively corresponding to the ejected plasma-state material, the successively ejected material normal to the target surface and the shock wave. It is also found that during the time interval of 0–9.0 ns after the femtosecond pulse strikes the target, the phase of the ejected plasma-state material varies beyond π due to the expansion and recombination, but the phase variation of the successively ejected material does not exceed π.
Ridgelet transform research based on the coordinate representation
Authors: Yu Hai-Jun  , Zhong Guo-Bao  , Ma Jian-Guo  , Ren Gang  ,   Department of Physics and Electronic Information Engineering,Huinan normal colledge, Huainan 232038, China;,   Shool of Physics and Material Science, Anhui University, Hefei 230039, China
Published: December 2020

Inspired by the wavelet transform in quantum mechanics, we define the new Ridgelet transform for quantum optics by rewriting the classic Ridgelet transform via the two-mode coordinate representation in Fock space. Furthermore, we give the explicit form of the asymmetric operator's integral and derive two useful formulas for the normal ordering of the two-mode operator with the help of the technique of integration within an ordered product (IWOP) of operators. By choosing the two-variable Mexican hat's mother wavelet function, we analyse the Ridgelet transforms of the coherent state, special squeezed coherent state, intermediary entangled state on the basis of the theories we have mentioned.
Study of resonance sound response for bubble cluster in ultrasonic field
Authors: Hu Jing  , Lin Shu-Yu  , Wang Ceng-Hui  , Li Jin  ,   Applied Acoustics Institute, Shaanxi Normal University, Xi'an 710062, China
Published: December 2020

Taking into consideration the influence of bubble cluster secondary sound radiation, the dynamic equation of spherical bubble clusters is obtained for two bubble clusters co-existing in the same ultrasonic field. Based on the original dynamic equation, the resonance response characteristics of the two-bubble-cluster oscillation system in ultrasonic field are discussed. Results showed that there are two resonance frequencies in this system, that is, low resonance frequency and high resonance frequency, due to the interaction between oscillating bubbles in the bubble cluster, and the two resonance frequencies are related with the bubble's eigenfrequency. The eigenfrequency of the bubbles is related to the bubble cluster's initial radius, bubble cluster's size and the number of bubbles. The coupling between bubble free vibration and driving acoustic may arouse the bubble's forced vibration, whose amplitude and initial phase are related to the bubble initial radius, bubble number density and driving sonic frequency.
Vibration of the bubble in bubbly liquids
Authors: Wang Yong  , Lin Shu-Yu  , Mo Run-Yang  , Zhang Xiao-Li  ,   Institute of Applied Acoustics, Shaanxi Normal University, Xi'an 710062, China
Published: December 2020

The vibration of bubbles in bubbly liquids has been studied when the driving sound field is fixed. The radius of the bubble will change when the bubble is driven by a driving acoustic field for a short time. This small change of radius is then fed back to the scattering process of the bubbles driven by the driving acoustic field. Thus the compound acoustic field including the scattered field of the bubble can be obtained. Then the bubble is again driven into vibration for a short time. By repeating the same procedure, the bubble vibration and its radius variation are simulated by a numerical method. It is shown that in the case of numerous bubbles in the liquid the vibration of a bubble is different from the case of only a single bubble in it. Because numerous bubbles will show interactions between one another, the radius of the bubble will change in different manner. For different size and content of bubbles, the radius of the bubble changes according to the following rules. The radius will oscillate in the vicinity of the equilibrium position; the radius oscillation shows a periodic cavitation process; the radius will vibrate during one cycle of cavitation; then, the radius will increase and oscillate in the vicinity of a certain value. Therefore, it is necessary that the bubble content should be considered in analyzing the vibration of the bubble in a bubbly liquid under a driving sound field.
Experimental study on the capillary flow in tubes of different shapes under microgravity condition
Authors: Xu Sheng-Hua  , Zhou Hong-Wei  , Wang Cai-Xia  , Wang Lin-Wei  , Sun Zhi-Wei  ,   Key Laboratory of Microgravity, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China
Published: December 2020

In this paper, we study the capillary flows in square tubes and in equilateral triangle tubes under microgravity condition by performing experiments in drop tower, and also compare them with those in circular tubes. Experimental results showned the influence of both size and shape of tubes on the capillary flow driven by interfacial forces. For tubes of the same shape, the influence of tube size is quite similar. Moreover, the capillary flows in square tubes and equilateral triangle tubes have some similarity with those in circular tubes with much smaller sizes. The results are helpful for understanding the capillary flows driven by interfacial forces with different parameters. And they are also useful for independently controlling the flow velocity and the volume flow rate by choosing appropriate tube shapes under microgravity condition.
Total ionizing dose effect on 0.18 μm narrow-channel NMOS transistors
Authors: Wu Xue  , Lu Wu  , Wang Xin  , Xi Shan-Bin  , Guo Qi  , Li Yu-Dong  ,   Key Laboratory of Functional Materials and Devices for Special Environments, Xinjiang Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Urumq 830011, China;,   Xinjiang Key Laboratory of Electronic Information Material and Device, Urumqi 830011, China;,   University of Chinese Academy of Sciences, Beijing 100049, China
Published: December 2020

This paper describes the total ionizing dose effect on 0.18 μm narrow-channel NMOS transistors which are exposed to a γ-ray radiation. Electrical parameters such as threshold voltage, leakage current, trans-conductance, drain-source conductance, and subthreshold slope extracted from the I-V curves are analyzed pre-and post-irradiation. Results show that the threshold voltage, the trans-conductance, and the drain-source conductance are sensitive to radiation compared to wide-channel NMOS transistors–the effect we call radiation induced narrow channel effect(RINCE). The amount of oxide-trapped charges and interface states which would degrade the threshold voltage and leakage current is induced in the STI oxide. The gate oxide is insensitive to irradiation. Combining the structure and process of devices, we finally discuss and analyze the above phenomenon in detail.
Effect of oxygen on stability performance of the IZO junctionless thin film transistors
Authors: Zhang Geng-Ming  , Guo Li-Qiang  , Zhao Kong-Sheng  , Yan Zhong-Hui  ,   Key Laboratory for Micro-Nano Optoelectronic Devices of Ministry of Education States Key Laboratory of Chemo/Biosensing and Chemometrics Hunan University, Changsha 410082, China;,   Ningbo Institute of Materials Technology & EngineeringChinese Academy of Sciences, Ningbo 315201, China
Published: December 2020

We report in this paper that low-voltage indium-zinc oxide (IZO) junctionless thin-film transistors (TFT) can be fabricated at room temperature, and the device stability performance influenced by oxygen pressure is studied. IZO junctionless TFT has a high mobility and novel structure, but the oxide channel layers are vulnerable due to the influence of oxygen and water molecules, which will lead to the degradation of the device stability. In this study, we fabricate transparent and conductive IZO thin-films at room temperature as channel layers, and source/drain electrodes by controlling the oxygen flow, and also analyze the effect of oxygen on the stability of oxide junctionless TFT. In order to operate at low-voltage (2 nanoparticle films as gate dielectric, which have electron double layers (EDL) effect and large gate capacitance, and the TFTs show excellent electrical performance with small operating voltage of 1 V, large on/off ratio(>106), small subthreshold swing(20 cm2/V·s). The study indicates that the resistivity of IZO thin-film fabricated in increasing oxygen content, leads the threshold voltage to drift in a positive direction, and makes operating mode of TFT change from depletion mode to enhanced mode.
Growth and characterization of the Mg0.57Zn0.43O alloy film
Authors: Qin Jie-Ming  , Cao Jian-Ming  , Jiang Da-Yong  ,   Institute of Materials Science and Engineering, Changchun University of Science and Technology, Changchun 130022, China;,   College of Physics, Inner Mongolia University of the Nationalities, Tongliao 028000, China
Published: December 2020

We report the growth of single cubic phase Mg0.57Zn0.43O (MZO) alloy film through the method of metal organic chemical vapor deposition (MOCVD) and the relation between the quality and thermal stability of the alloy film after heat treatment. From X-ray measurement, we found that the quality of cubic MZO film was significantly influenced by the heating temperature. At 500-850℃, the crystallization and surface morphology of the alloy film were improved obviously as the temperature increased. Also, the blue shift of absorption cut-off edge, broadened band gap and maintained single cubic structure were found with increasing temperature. However, up to 950℃, mixed phases were formed in cubic MZO alloy film. For the photoresponse measurement of the MSM unit devices synthesized by the cubic MZO alloy film under 15 V bias, we found that the response peak of devices was around 260 nm, rejection ratio of UV/Vis was about 4 orders of magnitude, saturated responsibility was 3.8 mA/W and the value of dark current was about 5 pA.
A theory of 3-4-5-wave resonance and conservation for ocean surface waves
Authors: Huang Hu  ,   Shanghai Institute of Applied Mathematics and Mechanics, Shanghai Key Laboratory of Mechanics in Energy Engineering, Shanghai University, Shanghai 200072, China
Published: December 2020

With respect to the whole of two elemental waves in ocean surface, capillary and gravity waves, a deterministic, rich and fundamental theory of 3-4-5-wave resonance and conservation for ocean surface waves in a finite depth is developed, which presents fully the preciseness, symmetry and completeness as compared with a variety of the classical, modern results, and provides an indispensable basis for the succeeding and universal statistical theory of ocean wave turbulence.
Warming and drying climate over Loess plateau area in China and its effect on land surface energy exchange
Authors: Zhang Qiang  , Huang Jing  , Zhang Liang  , Zhang Li-Yang  ,   Institute of Arid Meteorology, CMA, Key Laboratory of Arid Climatic Change and Reducing Disaster of Gansu Province; Key Open Laboratory of Arid Climatic Change and Disaster Reduction of CMA, Lanzhou 730020, China;,   Gansu Provincial Meteorological Bureau, Lanzhou 730020, China;,   Meteorological Bureau of YongJia, Wenzhou 325100, China;,   College of Atmospheric Sciences, Lanzhou University, Lanzhou 730000, China
Published: December 2020

China's Loess plateau, as one of the areas in the world, is vulnerable to ecological environment and sensitive to climate change. The characteristic of land surface process has been changing in this area, and it affects the formation and evolution of regional weather and climate. However, limited by observational land surface data, exchange process variation of the surface energy of the Loess plateau and its mechanism of response to climate change is limited. In this study, we combine the observed experimental data with the land surface model simulated data, test the previous four land surface models. It shows the CLM is reliable in Loess plateau. Then we use the observed data and model simulated data to analyze the variation of regional climate and the characteristics of land surface energy exchange, and discuss the effect of climate change on land surface energy exchange. It shows that Loess plateau is warming and drying in recent decades. It induces the increase in solar radiation, surface reflected radiation and surface longwave upward radiation. This makes the net radiation decrease. Correspondingly, surface latent heat flux, sensible heat flux and soil heat flux all have a decreasing trend. But the distribution ratio of components of surface heat flux is basically unchanged. In addition, the annual variation of sensible heat flux is controlled by solar radiation, and latent heat flux is controlled by solar radiation and precipitation. The annual variation of each component of surface heat flux is sensitive to precipitation, not sensitive to temperature. The climate acidification affected surface energy balance farmore than temperature rise.
Vibrating approximate solution for a class of El Nino-southern coupled oscillation dynamic model
Authors: Lin Wan-Tao  , Lin Yi-Hua  , Shi Lan-Fang  , Mo Jia-Qi  ,   State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamic, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China;,   College of Mathematics and Statistics, Nanjing University of Information Science and Technology, Nanjing 210044, China;,   College of Mathematics and Computer Science, Anhui Normal University, Wuhu 241003, China
Published: December 2020

A class of sea-air coupled oscillator dynamic model is studied. Using the parameter modification and average method for the singular perturbation, the vibrating approximate solution corresponding to El Nino-Southern Oscillation (ENSO) coupled oscillation dynamic model equations is obtained.
Residual stress analysis by grazing-incidence X-ray diffraction on beryllium films
Authors: Li Jia  , Fang Qi  , Luo Bing-Chi  , Zhou Min-Jie  , Li Kai  , Wu Wei-Dong  ,   Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900, China;,   Science and Technology on Plsama Physics Laboratory, Mianyang 621900, China
Published: December 2020

Measurements of residual stress in beryllium thin film under standard Bragg-Brentano geometry are always problematic. In this article, a new experimental method using grazing- incidence X-ray diffraction is presented according to the convential sin2Ψ method, which effectively increases the signal-to-noise ratio. Analysis shows that the assumption (isotropic material) is logical, because the values of stress results from the three families of planes are camparable. The stress gradient can be measured at diffrenent grazing incidence angles. The results indicate the uniformity of the residual stress of the thin film along various Φ directions.
Mono-station and single-band passive ranging based on oxygen spectrum
Authors: An Yong-Quan  , Li Jin-Hua  , Wang Zhi-Bin  , Wang Zhao-Ba  ,   Engineering Technology Research Center of Shanxi Province for Opto-Electronic Information and Instrument, North University of China, Taiyuan 030051, China;,   Key Laboratory of Instrumentation Science and Dynamic Measurement, North University of China, Taiyuan 030051, China;,   Key Laboratory of Electronic Measurement Technology, North University of China, Taiyuan 030051, China
Published: December 2020

Passive ranging has received much attention because of its concealment. The distance between sensor and the object is measured by the infrared radiation attenuation in atmosphere. A mono-station single-band ranging method based on spectra transmission characteristics of oxygen is developed. The concept of light of sight (LOS) is introduced. The ray tracing model is built. With the method of discrete transfer and the discretization of physical properties distribution field of oxygen, the radiation strength in oxygen band of the target is calculated by the LOS along the seeker detectors. The radiation strengths in resonant frequency band and non-resonant frequency band are analyzed. The distance is achieved by their relation. High-resolution spectrometer is adopted to build experiment platform. Real-time dynamic ranging can be implemented by field calibration. The present experimental range is 75-200 m. The maximal relative error is 7.56%.
Transient electroosmotic flow of general Jeffrey fluid between two micro-parallel plates
Authors: Liu Quan-Sheng  , Yang Lian-Gui  , Su Jie  ,   School of Mechanical Science, Inner Mongolia University, Hohhot 010021, China
Published: December 2020

In this study, analytical solutions are presented for the unsteady electroosmotic flow of linear viscoelastic fluid between micro-parallel plates. The linear viscoelastic fluid used here is described by the general Jeffrey model. Using Laplace transform method, the solution involves analytically solving the linearized Poisson-Boltzmann equation, together with the Cauchy momentum equation and the general Jeffrey constitutive equation. By numerical computations, the influences of the dimensionless relaxation time λ1 and retardation time λ2 on velocity profile are presented. In addition, we find that when the retardation time is zero, the smaller the relaxation time, the more close to the Newtonian fluid velocity profile the velocity profile is. With the increases of the relaxation time and the retardation time, the velocity amplitude also becomes bigger and bigger. As time goes by, the velocity tends to be stable gradually.
Surface microstructure and stress characteristics in pure zirconium after high current pulsed electron beam irradiation
Authors: Cai Jie  , Ji Le  , Yang Sheng-Zhi  , Zhang Zai-Qiang  , Liu Shi-Chao  , Li Yan  , Wang Xiao-Tong  , Guan Qing-Feng  ,   College of Material Science and Engineering, Jiangsu University, Zhenjiang 212013, China
Published: December 2020

High-current pulsed electron beam (HCPEB) technique was applied to irradiate the samples of pure zirconium. The microstructures and defects of the irradiated surface are investigated by using X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). XRD results show that the high value of stress (GPa order) is introduced within the irradiated surface layer, while the formation of {0002}, {1012}, {1120} and {1013} textures are present after HCPEB irradiation. Microstructure observations demonstrate that the surface craters are rarer, and almost no craters are present after multiple pulses HCPEB irradiation, which is evidently different from the case of other metal materials irradiated by HCPEB. Moreover, a large number of ultrafine grains are formed on the irradiated surface. Martensitic transformation occurs and severe plastic deformation is also induced due to the superfast melting and cooling processes. After one- pulse irradiation, the dislocations are the dominant defects, while the amount of twins is less. After five pulses, the dislocation density and the number of deformation twins increase evidently, whereas dense deformation twins are the central microstructures after ten-pulse irradiation, coupled with the appearance of secondary twins occasionally. The formation of these deformed structures results in a significant effect both on the evolution of surface textures and on grain refinement. It is suggested that HCPEB technique provides an impactful approach for hardening of zirconium and zirconium alloys.
Properties and mechanism analysis of metal/Ge ohmic contact
Authors: Yan Guang-Ming  , Li Cheng  , Tang Meng-Rao  , Huang Shi-Hao  , Wang Chen  , Lu Wei-Fang  , Huang Wei  , Lai Hong-Kai  , Chen Song-Yan  ,   Semiconductor Photonics Reseach Center, Department of Physics, Xiamen University, Xiamen 361005, China
Published: December 2020

Large contact resistance due to Fermi level pinning effect at the interface between metal and n-type Ge strongly restricts the performance of Ge device on Si substrate. In this paper, the contacts of metal Al and Ni with n-type Ge and p-type Ge epitaxial layers grown by UHV/CVD are comparatively studied. It is found that the contact of NiGe/n-Ge is better than that of Al/n-Ge at the same dopant concentration. When the concentration of P is 21019 cm-3, the ohmic contact of NiGe/n-Ge with c down to 1.4310-5 cm2 is demomstrated, which is about one order of magnitude lower than that of Al/n-Ge contact. The specific contact resistance of NiGe/p-Ge is 1.6810-5 cm2 when the B concentration is 4.21018 cm-3, corresponding to that of Al/p-Ge. Compared with Al/n-Ge contact, P segregation at the interface between NiGe and Ge, rather than lowering Schottky barrier height, is the main reseaon for achieving the low specific contact resistance. NiGe/Ge contact should be a good choice for contact electrode for Ge devices at present.
Nano surface two-dimensional periodic half-round grooves enhanced light absorption in silicon film solar cell
Authors: Liu Zhen  , Wang Yu-Xiao  , Song Ying-Lin  , Zhang Xue-Ru  ,   Department of Physics, Harbin Institute of Technology, Harbin 150001, China
Published: December 2020

The influence of nano surface two-dimensional periodic half-round grooves on the enhancement of light absorption in silicon film solar cell is studied with the finite-difference time-domain method. The result shows that the broadband solar spectrum absorption is enhanced. The light optical absorption in Si thin-film cell is enhanced by optimizing the thickness of SiO2 anti-reflection film and the radius of half-round grooves, and the total integrated absorption of solar spectrum wavelength in a range from 300 nm to 1000 nm is about 117% greater than that of single silicon thin film.
Dislocation motion during rapid thermal processing of single-crystalline silicon wafers
Authors: Xu Ling-Mao  , Gao Chao  , Dong Peng  , Zhao Jian-Jiang  , Ma Xiang-Yang  , Yang De-Ren  ,   State Key Laboratory of Silicon Materials, Department of Material Science and Engineering, Zhejiang University, Hangzhou 310027, China
Published: December 2020

We have investigated the motion of dislocations originating from Vicker indentations in single-crystalline silicon wafers subjected to high temperature rapid thermal processing (RTP) under different ambients. It is found that the dislocations move very rapidly due to the release of residual stress around the indentations during the RTP. Moreover, as the RTP temperature exceeds 1100 °C, the dislocation gliding distances in the specimens subjected to the RTP in N2 atmosphere are much shorter than in Ar ambient. We believe that the nitrogen atoms injected into the indentation by the RTP under N2 ambient exhibit a pinning effect on dislocation motion. It is thus shown that the high temperature RTP in N2 ambient can improve the mechanical strength of silicon wafer.
The fabrication of the antireflective periodic nano-arrary structure on Si surface using nanoimprint lithography and the study on its properties
Authors: Zhang Zheng  , Xu Zhi-Mou  , Sun Tang-You  , He Jian  , Xu Hai-Feng  , Zhang Xue-Ming  , Liu Shi-Yuan  ,   School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, China;,   State Key Laboratory of Digital Manufacturing Equipment and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
Published: December 2020

The intrinsic Fresnel reflection of Si surface, which causes more than 30% of the incident light to be reflected back from the surface, seriously influences the photoelectric conversion efficiency of Si-based semiconductor photoelectric device, such as solar cell and infrared detector. Recently, how to find a simple and efficient method, which is also suitable for mass production, aiming to suppress the undesired reflectivity and therefore improving the efficiency of the device, has become a research focus. In this work, we successfully convert a 2D nanopillar array structure into the Si surface via the nanoimprint lithography. The nanopillar has a flat surface and a paraboloid-like side wall profile. The period and the height of the hexagonal array structure are 530 nm and 240 nm, respectively. The cut-paraboloid nanopillar structure generates a relatively smooth gradient of the refractive index in the optical interface, which plays a key role in suppressing the Fresnel reflection in a wide range of wavelength. The reflectivity of the nanopillar arrayed Si surface is tested in a wavelength range from 400 to 2500 nm at an incident angle of 8° during the measurement. Compared with the unstructured Si, the structured Si has a reflectivity that significantly decreases in the test area: in a wavelength range from 400 to 1200 nm, and the reflectivity of the silicon surface is less than 10%. Specifically, the reflectivity is almost zero at a wavelength of about 1360 nm. The results are confirmed with the effective medium and rigorous coupled-wave theory.
Application of the composite adiabatic passage technique in the Landau-Zener model with harmonic interaction modulation
Authors: Hu Jing-Yu  , Mao Teng-Fei  , Dou Fu-Quan  , Zhao Qing  ,   School of Physics, Beijing Institute of Technology, Beijing 100081, China;,   College of Physics and Electronic Engineering, Northwest Normal University, Lanzhou 730070, China
Published: December 2020

In quantum information processing, an extreme high fidelity is needed. We apply a composite adiabatic passage (CAP) technique in the Landau-Zener model with harmonic interaction modulation in order to study the transition probability of the system with different model parameters. We find that this method could suppress the non-adiabatic oscillations in the transition probability and reduce the admissible error. This method could also enlarge the parameter regimes of high transition probability. Because of these good results, the Landau-Zener model with harmonic interaction modulation and CAP technique could be potentially important tools for ultrahigh-fidelity quantum information processing.
Dynamic behavior and chaos synchronization of a simple nonlinear time-delayed system
Authors: Xiao Jian-Xin  , Chen Ju-Fang  , Peng Jian-Hua  ,   College of Physics Science and Technology, Shenzhen University, Shenzhen 518060, China;,   Department of Physics, Northeast Noraml University, Changchun 130024, China
Published: December 2020

Hopf bifurcation and chaotic properties of a simple second order time-delayed system, which includes bifrucation point, bifurcation direction and the stability of bifrucating periodic solutions, are analyzed. We obtain analytically the phase trajectory equations when the delay degenerates. Furthermore, through bifurcation diagram drawn by means of numerical simulation, the route from period-doubling bifurcation to chaos is reaveled; using single linearly combinating signals and the feedback control method, we achieve partial synchronization of the system. Combining the active-passive method with the linear feedback method, we have realized complete synchronization. In addition, we have designed and built an electronic experimental line, from which the same result as the theoretical analysis or numerical results are obtained.
The instantaneous linewidth measurement of DFB laser with ultrashort delay
Authors: An Ying  , Du Zhen-Hui  , Xu Ke-Xin  ,   State Key Laboratory of Precision Measuring Technology and Instruments, Tianjin University, Tianjin 300072, China;,   College of Information Engineering, Hebei United University, Tangshan 063009, China
Published: December 2020

The instantaneous linewidth in the process of tuning is a very important parameter of laser, however only static linewidth in steady state could be obtained by all kinds of measurement at present. So we proposed a method of measuring instantaneous linewidth by time-frequency analysis based on local mean decomposition, and after its validity of extracting the instantaneous phase noise of simulation signal was proved, we set the heterodyne measurement system with ultrashort delay (about 0.5 ns) which came from 10 cm optical path difference. Finally, we not only extracted the time-frequency spectrum of the beat signal’s phase noise power, but also obtained the instantaneous linewidth of distributed-feedback diode laser under the pulse current for the first time so far as we Rnow.
Backscattered Light diagnostic technique on Shen Guang-III prototype Laser Facility
Authors: Wang Feng  , Peng Xiao-Shi  , Yang Dong  , Li Zhi-Chao  , Xu Tao  , Wei Hui-Yue  , Liu Shen-Ye  ,   Research Center of Laser Fusion, CAEP, Mianyang 621900, China
Published: December 2020

Laser and plasma interaction (LPI) is the important part for the study of inertial confinement fusion (ICF). In order to have an investigation for the energy and spectrum of scattered light produced by laser-plasma interaction in Shen Guang-III prototype laser facility, a backscattered light diagnostic system was developed. This paper introduces the design and the damping factor of this system. The laser focus shape after using the coherent phase plate (CPP) has been analyzed. Experimental results with the energy and spectrum of backscattered light have been provided and compared after adding the CPP on the laser beam. It is found that the fraction of backscattered light can be reduced to below 5% under the laser condition 8×800 J after using the CPP. And the spectrum range with CPP is narrower than that without CPP on laser beam. These experimental data can improve the research on hohlraum energy.
First-principles study of structural stability and electronic properties of tetragonal and orthorhombic as well as monoclinic K0.5Na0.5NbO3
Authors: Liu Shi-Yu  , Yu Da-Shu  , Lü Yue-Kai  , Li De-Jun  , Cao Mao-Sheng  ,   College of Physics and Electronic Information, Tianjin Normal University, Tianjin 300387, China;,   College of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081, China
Published: December 2020

The energetic stability, structural and electronic properties of tetragonal, orthorhombic, as well as monoclinic K0.5Na0.5NbO3 are systematically studied using first-principles supercell model and virtual crystal approximation based on density functional theory with local density approximation and generalized gradient approximation. Our calculated results show that the total energy differences among the three K0.5Na0.5NbO3 phases are small, which are well consistent with the easy phase equilibrium at the phase boundary in the experiments. Furthermore, we also find that the total energy of the monoclinic phase is lower than that of the other two phases, which suggests that the monoclinic structure is energetically more stable than the others. Moreover, the calculated structural parameters are in good agreement with experimental values. In addition, the electronic structure results show that the bonding interaction in the monoclinic structure is stronger than that in the other structures, also indicating that the monoclinic structure is the most stable one.
Analysis of characteristics and key influencing factors in magnetomechanical behavior for cable stress monitoring
Authors: Zhang Peng  , Liu Lin  , Chen Wei-Min  ,   College of Optoelectronic Engineering, Chongqing University, Key Lab. for Optoelectronic Technology & Systems of Ministry of Education, Chongqing 400044, China
Published: December 2020

Until recently the magnetomechanical behavior has been rather poorly understood with contradictory results and interpretations from different investigators in the study of stress monitoring by magnetic method. Based on the domain motion and field-induced magnetization process of magnetic material, the stress-induced magnetization process in two different magnetization states is analyzed in detail. Characteristics of the magnetomechanical behavior are revealed. Domain motion caused by stress always makes materials tend to stable state of free energy minimum and accordingly the magnetization will approach the anhysterestic magnetization. Moreover, it can be concluded that magnetization state is an essential factor influencing the magnetomechanical behavior. Experiments of magnetomechanical behavior for galvanized steel wire have been conducted for different magnetization state, and the results are in accord with the theoretical analyses. The magnetomechanical behavior is changed with magnetization state, which can be effectively used to explain the existing complex and diverse research results.
Retrieving vertical profile of aerosol extinction by multi-axis differential optical absorption spectroscopy
Authors: Wang Yang  , Li Ang  , Xie Pin-Hua  , Chen Hao  , Xu Jin  , Wu Feng-Cheng  , Liu Jian-Guo  , Liu Wen-Qing  ,   Key Laboratory of Environmental Optical and Technology, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, China
Published: December 2020

Using the oxygen dimer (O4 information measured by multi-axis differential optical absorption spectroscopy (MAX-DOAS)), an inversion method of vertical profile of aerosol extinction based on nonlinear optimal estimation algorithm is developed. At first we study how to calculate some parameters (weighting function, the covariance matrices of measurement and a priori) of the algorithm and design nonlinear iteration strategy suited to Chinese region where aerosol usually shows rapid variation and high load. Then this inversion method is verified by computer simulation combined with discussion about error source in three typical cases of low, high and elevated aerosol. After that a continuous observation is reported in the city of Hefei. The aerosol optical depth (AOD) derived from MAX-DOAS is compared with that of CE318 sun photometer and the correlation coefficient is 0.94. The total relative error of AOD is about 20%. In addition the aerosol extinction in the lowest altitude (0-0.3 km) is compared with that of visibility meter and the correlation coefficient is about 0.65. The total relative error of surface-near aerosol extinction is about 25%. Both of simulation verification and comparison experiment indicate that the inversion method can well rebuild the vertical profile of aerosol extinction in the troposphere.
Vib-rotational spectrum of ultracold cesium molecule 0g- long range state
Authors: Wang Li-Rong  , Feng Xin-Lin  , Ma Jie  , Zhao Yan-Ting  , Xiao Lian-Tuan  , Jia Suo-Tang  ,   State Key Laboratory of Quantum Optics and Quantum Optics Devices, Laser Spectroscopy Laboratory, Shanxi University, Taiyuan 030006, China
Published: December 2020

In this paper, high-resolution vib-rotational spectrum of ultracold cesium molecule in its first excited state of 6S1/2+6P3/2 with dissociation limit 0g- long range state is obtained by cold atom fluorescence frequency modulation method. The rotation constants of different vibration energy levels of cesium molecule for vibrational quantum number from 0 to 51 are achieved. The results are in good agreement with the theoretical results given by Daniel.
Ray optics calculation of axial force exerted by a highly focused Gaussian beam on a left-handed material sphere
Authors: Lai Xiao-Lei  ,   Depart of Basic Courses, Zhengzhou College of Science and Technology, Zhengzhou 450064, China
Published: December 2020

Theoretical expressions and numerical calculations of axial forces for a left-handed material sphere, exerted by a highly focused Gaussian beam, in the ray optics regime are presented. Comparison is made between a dielectric sphere and a left-handed material sphere. The position at which the maximal magnitude of the axis force occurs is determined by the beam and the sphere parameters. A very strong axial force can be obtained from a low refractivity of a left-handed material sphere, exerted by a highly focused Gaussian beam, which is hundred times larger than that of a dielectric sphere.
Soliton trapping of dispersive waves during supercontinuum generation in photonic crystal fiber
Authors: Wang Wei-Bin  , Yang Hua  , Tang Ping-Hua  , Han Fang  ,   Key Laboratory for Micro/Nano Optoelectronic Devices of Ministry of Education, College of Information Science and Engineering, Hunan University, Changsha 410082, China
Published: December 2020

Using the generalized nonlinear Schrödinger equation, we present a numerical study of trapping of dispersive waves by solitons during femtosecond pumped supercontinuum generation in photonic crystal fiber with single or double zero dispersive wavelength. Numerical simulation results show that the generated supercontinuum in photonic crystal fiber with two zero dispersive wavelengths includes both blue-shifted dispersive wave (B-DW) and red-shifted dispersive wave (R-DW) while the generated supercontinuum in photonic crystal fiber with single zero dispersive wavelength has only blue-shifted dispersive wave. We find a novel phenomenon that not only B-DW but also R-DW can be trapped by solitions via four-wave mixing when the group-velocity matching between the soliton and the dispersive wave is satisfied, thus leading to the generation of new spectral components. In order to clearly display the evolution of soliton trapping of dispersive waves, the spectrogram of output pulses is observed using cross-correlation frequency-resolved optical gating technique.
Rate-dependences of deformation mechanisms in NiTi shape memory alloys
Authors: Liu Hong-Tao  , Sun Guang-Ai  , Wang Yan-Dong  , Chen Bo  , Wang Xiao-Lin  ,   Key Laboratory for Anisotropy and Texture of Materials of Ministry of Education, Northeastern University, Shenyang 110819, China;,   Key Laboratory for Neutron Physics of Chinese Academy of Engineering Physics, Institute of Nuclear Physics and Chemistry, Mianyang 621900, China
Published: December 2020

In the NiTi shape memory alloys (SMAs), the macro-mechanical deformations and the microstructural evolutions at different strain-rates (0.001-1200 s-1) are investigated. It is found that the detwinning stress of martensitic twin increases with strain-rate increasing, which indicates that the detwinning stress has the positive strain-rate dependence. A large number of detwinning regions are found in the NiTi specimen which is deformed at the strain-rate of 10 s-1 under tension. However, with the strain-rate further increasing up to 100 s-1 and 1200 s-1, no detwinning region is observed and many twins still exist. It is shown that the detwinning rates of martensitic twin in NiTi SMAs are in a range of 10-100 s-1. Simultaneously, thermally-induced austenite is detected in the NiTi specimens deformed at high strain-rates (≥qslant10 s-1). It is ascribed to the fact that there is a change from the isothermal process to the adiabatic process when the tensile strain-rate goes up to a critical value. Additionally, a small shoulder peak is detected in differential scanning calorimeter peak of 1200 s-1 strain-rate specimen, indicating that the two-stage phase transformation occurs.
Prediction of lattice thermal conductivity of solid argon from anharmonic lattice dynamics method
Authors: Bao Hua  ,   University of Michigan-Shanghai Jiao Tong University Joint Institute, Shanghai Jiao Tong University, Shanghai 200240, China
Published: December 2020

Anharmonic lattice dynamics method is employed to investigate the phonon frequency and relaxation time without any fitting parameters. The phonon relaxation time is used in Boltzmann transport equation to predict the lattice thermal conductivity of solid argon between 10 K and 80 K, and the results agree very well with experimental data. The effects of calculation parameters on the prediction accuracy are also analyzed, including mesh size of the reciprocal lattice points, and the broadening factor of delta function. The contribution of each individual phonon mode to the thermal conductivity is investigated. It is found that higher frequency phonons contribute more to the thermal conductivity at higher temperature, which is consistent with previous theoretical results.