bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of complex formation on the electron-phonon coupling of all-trans-β-carotene iodine solution
Authors: Wang Meng-Zhou  , Jiang Yong-Heng  , Liu Tian-Yuan  , Sun Cheng-Lin  , Li Zuo-Wei  ,   State Key Laboratory of Superhard Materials, Jilin University, Changchun 130012, China;,   College of Physics, Jilin University, Changchun 130012, China
Published: December 2020

The uv-vis absorption and resonance Raman spectra of all-trans-β-carotene in polar solvent 1, 2-dichloroethane with iodine are measured at 293 K. The results indicate that the absorption peak of all-trans-β-carotene in the complex disappears at 460 nm and instead a new peak of the complex formed by all-trans-β-carotene and iodine is found at 1000 nm, so that the all-trans-β-carotene within the complex cannot produce the resonance Raman spectrum by 514.5 nm excitation laser. The Raman scattering cross section of CC bonds of all-trans-β-carotene taht does not form in complex decreases, its full bandwidth broadens and electron-phonon parameter increases with the increase of concentration of the complex, because when the concentration of the complex increases, the disorder increases in the solution and the molecular structural order decreases. These phenomena are analyzed using the coherent weakly damped electron-lattice vibration mode, the effective conjugation length mode as well as the theory of amplitude mode in this work.
Synthesis and magnetic properties of three-dimensional self-assembly Eu3+-graphene composite material
Authors: Wang Dong-Dong  , Gao Hui  ,   School of Physical Science and Technology, Lanzhou University, Lanzhou 730000, China
Published: December 2020

The three-dimensional self-assembly Eu3+-graphene composite materials are synthesized through a one-pot hydrothermal reaction under 180 ℃. The obtained samples are analyzed through powder X-ray diffraction, scanning electron microscope, and transmission electron microscopy. The results show that each sample has porous structure and no independent Eu3+ agglomerates. Raman spectrum and Fourier transform infrared spectrum analyses indicate Eu3+ is well complexed with graphene through oxygen-containing groups. The magnetic properties are measured using vibrating sample magnetometer. The magnetic hysteresis loop shows the corresponding coercivity Hc ≈ 39.61 Oe (1 Oe=79.5775 A/m) and the magnetization saturation Ms ≈ 0.08 emu/g that indicates that the sample presents weak ferromagnetism and good soft magnetic properties compared with graphene.
Simulation of the Brownian motion of particle in an optical trap based on the auto-regressive model
Authors: Wang Zi-Qiang  , Zhong Min-Cheng  , Zhou Jin-Hua  , Li Yin-Mei  ,   Department of Optics and Optical Engineering, University of Science and Technology of China, Hefei 230026, China
Published: December 2020

An auto-regressive (AR) model is established by analysing the characteristic of the particle motion in an optical trap. In this paper, a new method based on the AR model is investigated to simulate the Brownian motion of the particle in an optical trap. When optical stiffness values are 10, 20, 50 pN/μm respectively, the displacement signals of 1 μm diameter particle in these optical traps are simulated with this method. Their simulative autocorrelation function of the motion of the particle accords with their theoretical autocorrelation function. In order to further clarify the validity of the model, the particle signals are respectively simulated with the AR model method and the Monte-Carlo method, then the stiffness values are calibrated with power spectrum density method. The results show that the stiffness value based auto-regressive simulation can have the same precision as that based the Monte-Carlo simulation, therefore, the AR method can simulate effectively the motion of the particle in the optical trap.
Synchronization of chaotic systems with input constraint
Authors: Xie Lin-Bo  , Zhou Zhi-Gang  , Zhang Zheng-Dao  ,   Key Laboratory of Advanced Process Control for Light Industry (Ministry of Education) Jiangnan University, Wuxi 214122, China
Published: December 2020

It is well known that the dynamics of the chaotic system is very sensitive to the initial conditions of the state, and the synchronization of two identical chaotic systems is only obtained, in general, with the high gain control law once their initial conditions are in a certain large deviation. Furthermore, the initial conditions are commonly unknown in practice, which causes difficulty in synchronizing two chaotic systems. This paper deals with the synchronization of two unified chaotic systems with input constraint. First, the scalar sign function is utilized to approximate the constrained non-smooth input function so that a continuous smooth nonlinear input function and an approximated nonlinear synchronized error system are obtained. Then, an optimal linear quadratic regulator (LQR) continuous-time control law is designed based on the optimal linear model, which is constructed at the sampled operating point of the afore-mentioned approximated nonlinear synchronized error system. To reduce the high magnitude of the obtained control law, the continuous-time control law is digitally redesigned for the implementation and an iterative procedure is proposed to adjust the weighting matrices in the LQR performance index so as to avoid input saturation occurs. Finally, three illustrative examples of the Lorenz, the Chen and the L chaotic systems decomposed from the unified chaotic system are given to demonstrate the effectiveness of the proposed method.
Contribution of typhoon over coastal waters to summer rainfall in eastern China
Authors: Shen Qian  , Zhang Shi-Xuan  , Zhao Jun-Hu  , Wang Xu-Jia  ,   College of Atmospheric Sciences, Lanzhou University, Lanzhou 730000, China
Published: December 2020

Now, it is difficult to consider the typhoon rainfall in the short-term climate prediction. This is mainly because the typhoon is a strong synoptic scale system and it does not match the scale of the short-term climate forcast. It is a factor restricting the great improvement of forecast. By using station precipitation data in eastern China from 1960 to 2011 and CMA-STI Best track dataset for tropical cyclones over the western north pacific, we analyse the strength variation of typhoon influence from month and quarter scale in summer by determining the typhoon influence index, then discuss the contribution of typhoon rainfull to summer rainfall in eastern China. 1) On average, the typhoon is enhanced from June to August, it is weakest in June, and strongest in August. 2) From the distribution of typhoon rainfall and its proportion of the total precipitation in eastern China, totally, the tyhoon rainfall is higher in eastern region than in the western region on the same latitude, and it is higher in southern region than in the northern region on the same longitude. The ratio of typhoon rainfall to the total precipitation could reach up to 10% in the South of the Yangtze river region. The typhoon rainfall can also reach up to 100 mm in the southeast coastal area in July and August, which can amount to 40% of the total precipitation during the month. 3) The correlation of the typhoon influence index with summer precipitation shows that the typhoon’s influences on the precipitation in eastern China are different spatiotemporally. The results indicate that the negative correlation is in southern part of China in June, the positive correlation is the southeast coastal area in July, the positive correlation is in the south China in August, and the negative correlation is in the middle and lower reaches of the Yangtze river region, which are mainly due to the typhoon, summer moonsoon, and high pressure in the north-east pacific subtripics respectively.
Chaotic characteristic analysis for traffic flow series and DFPSOVF prediction model
Authors: Zhang Yu-Mei  , Wu Xiao-Jun  , Bai Shu-Lin  ,   School of Computer Science, Shaanxi Normal University, Xi’an 710062, China;,   Xi’an Electronic Engineering Research Institute, Xi’an 710100, China;,   School of Electronics and Information, Northwestern Polytechnical University, Xi’an 710072, China
Published: December 2020

Time delay and optimal embedding dimension for the real measurement traffic flow series, which are used by mutual information method and false nearest-neighbor method, respectively, are determined for phase space reconstruction of the traffic flow series. The saturation correlation dimension and the largest Lyapunov exponent for traffic flow series are calculated to estimate its chaotic characteristics. Based on the least mean square (LMS) algorithm, a novel second-order Volterra model using Davidon-Fletcher-Powell method (DFPSOVF) is constructed, in which a variable convergence factor based on a posteriori error assumption, characteristic of real-time change with the input signal, is applied. DFPSOVF model can avoid some problems caused by improper selection of parameters when using LMS adaptive algorithm for coefficient adjustment in Volterra model. DFPSOVF model can also be applied to short-term traffic flow prediction with chaotic characteristics. Results show that when model memory length is consistent with embedding dimension of traffic flow series, it obtains higher prediction accuracy, which can meet the needs for traffic guidance and traffic control, and can also provide a new method, a new idea and engineering application reference for intelligent traffic control.
Precision measurement of resonate frequency and the effective cavity length of the high finesse optical micro-cavity
Authors: Du Jin-Jin  , Li Wen-Fang  , Wen Rui-Juan  , Li Gang  , Zhang Tian-Cai  ,   State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Opto-Electronics, Shanxi University, Taiyuan 030006, China
Published: December 2020

Ultra-high finesse micro-resonator plays an important role in realizing the interaction between atoms and cavity field in the study of cavity quantum electrodynamics (QED) system, weak optical nonlinear effects and micro-optic devices. By measuring basic parameters of the microcavity, the atom-cavity coupling coefficient and the cavity decay rate can be determined precisely. It is also useful for exploring the dynamic characteristics of the system. However, it has difficulty in determining resonate frequency and effective cavity length due to the structure of the ultra-high finesse optical microcavity itself and the characteristics of multilayer coating. In this paper, we demonstrate the precision measurement of effective cavity length under different resonant frequencies which our cavity mirror is coated with 37 layers of dielectric film. The theoretical expectation when using the revised model of the multilayer coating agrees well with that of the experiment; and the measurement error for longitudinal mode interval is below 0.004 nm which is two orders of magnitude better than that obtained in previous unrevised model. The tiny depths into mirror coatings that the standing-wave light field inside the cavity penetrates are given for different mode numbers. This method may be applied to other micro resonator in the precision measurement.
Generation and evolution of vacancy-type defects in nano-Cu films during plastic deformation by means molecular dynamics
Authors: Xu Shuang  , Guo Ya-Fang  ,   Department of Mechanics, School of Civil Engineering, Beijing Jiaotong University, Beijing 100044, China
Published: December 2020

Molecular dynamics simulations were performed to study the plastic deformation of Cu films under uniaxial tension. The generation and evolution mechanisms of vacancy-type defects were carefully studied. In the simulations, embedded atom method (EAM) was selected as the interatomic potential function. Simulation results indicate that the plastic deformation is due to the dislocation nucleation near free surfaces. Both the generation and evolution of vacancy-type defects are related to dislocation activities. Vacancy-type defects prefer to nucleate at the position of dislocation jogs and the intersection of stacking faults initially, and finally exist in the form of single vacancy, vacancy clusters and stacking-fault tetrahedrons.
Thickness dependence of critical current density in MgB2 films fabricated by hybrid physical-chemical vapor deposition
Authors: Chen Yi-Ling  , Zhang Chen  , He Fa  , Wang Da  , Wang Yue  , Feng Qing-Rong  ,   Application Superconductivity Research Center, State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China;,   School of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871, China
Published: December 2020

MgB2 superconducting films with a thickness of 10 nm to 8 μ have been prepared on SiC substrates by hybrid physical-chemical vapor deposition (HPCVD). The study on Tc and Jc shows that as the film grows thicker, Tc increases and then keeps stable, which Jc increases at first, and then drops dramatically. We get the maximum Tc at 41.4 K and Jc at 2.3× 108 A·cm-2. This also shows that we can use the method of HPCVD to prepare high-quality of clean MgB2 film. And its thickness can be from 10nm ultrathin films and 100 nm thin films up to 8 μm thick film. It is the first time so far as we know that Tc and Jc are studied in this range of thickness. This will lead to a complete and systematical understanding of the superconducting MgB2 films. And it is also important and practical to choose the thickness when preparing MgB2 films.
Simulation study based on the COMSOL Mutiphysics to the surface plasmon resonance of Cu2S quantum dots
Authors: Wang Yue  , Liu Li-Wei  , Hu Si-Yi  , Li Qi-Yang  , Sun Zhen-Hao  , Miao Xin-Hui  , Yang Xiao-Chuan  , Zhang Xi-He  ,   School of science, Changchun University of Science and Technology, Changchun 130000, China;,   Southwest Institute of Technical Physics, Chengdu 610041, China
Published: December 2020

As a new type of nano-semiconductor material, Cu2S quantum dot (QD) has received much attention due to its particular chemical and optical properties. In this paper we use COMSOL Multiphysics 4.2a software, select Radio Frequency model and combine the Maxwell theory to simulate and analyze the factors influencing Cu2S with its SPR. By using the Kretschmann prism coupling model, changing the QD size, the refractive index of QD solvent, the wavelength of incident light and coated substance of the QD, the data about how the SPR appears and the effectsof those factors are obtained. So the simulation results will be a theoretical foundation and reference to the further study.
Passivation property of -Si：H/SiNx stack-layer film in crystalline silicon solar cells
Authors: Zheng Xue  , Yu Xue-Gong  , Yang De-Ren  ,   State Key Lab of Silicon Materials, Zhejiang University, Hangzhou 310027, China
Published: December 2020

The -Si:H/SiNx stack-layer films are piepared by plasm-enhanced chemical vapor deposition to passivate crystalline silicon solar cells. Effective lifetime of minority carrier is used to characterize their passivation property and the passivation mechanism is analyzed by simulating the high-frequency capacitance-voltage curves. It is found that compared to -Si:H films prepared by the same method, -Si:H/SiNx films show better passivation property. Through thermal treatment at different temperatures, the passivation property of -Si:H/SiNx films is improved to the best at 300 ℃ first, and then degraded with rising temperature. Annealing at 300 ℃ can make -Si:H/SiNx films show a better passivation property than -Si:H films in 90 min. Simulation results indicate that the passivation property of -Si:H/SiNx films is mainly determined by the state density at the -Si:H/Si interface.
Synchronization, antisynchronization and amplitude death in coupled fractional order bistable oscillators
Authors: Wang Li-Ming  , Wu Feng  ,   Department of physics, Langfang Teachers College, Langfang 065000, China;,   Department of Physics, Tianjin University of Technology, Tianjin 300191, China
Published: December 2020

The dynamic behaviors of coupled fractional order bistable oscillators are investigated extensively and various phenomena such as synchronization, anti-synchronization, and amplitude death, etc. are explored. Based on the bistable characteristics of P-R oscillator with specific parameters, effects of initial conditions and coupling strength on the dynamic behaviors of the coupled fractional order bistable oscillators are first investigated by analyzing the maximum condition of Lyapunov exponent, the maximum Lyapunov exponent and the bifurcation diagram, etc. Further investigation reveals that the coupled fractional order bistable oscillators can be controlled to form chaotic synchronization, chaotic anti-synchronization, synchronous amplitude death, anti-synchronous amplitude death, partial amplitude death, and so on by changing the initial conditions and the coupling strength. Then, based on the principle of Monte Carlo method, by randomly choosing the initial conditions from the phase space, we calculate the percentage of various states when changing the coupling strength, so the dynamic characteristics of coupled fractional-order bistable oscillators can be represented by using the perspective of statistics. Some representative attractive basins are plotted, which are well coincident with numerical simulations.
Measurement of the spatial coherence of extended light source by twin beams-interference method
Authors: Man Tian-Long  , Wan Yu-Hong  , Jiang Zhu-Qing  , Wang Da-Yong  , Tao Shi-Quan  ,   Institute of Information Photonics Technology, Beijing University of Technology, Beijing 100124, China; College of Applied Sciences, Beijing University of Technology, Beijing 100124, China
Published: December 2020

The coherence of light source have been employed in many aspects, such as optical processing and optical coherence holography. For this reason it has attracted vast interest in developing quantitative methods for measuring the spatial coherence characteristics of an optical field. We propose a novel method for measuring the spatial coherence degree of optical fields based on the triangular interferometer. Spatially separated twin beams are formed by an interferometer, and the interferogram formed by the twin beams is captured by an image detector. Because the separation of the twin beams is related to the coordinate position of the input beam, a series of positions are sampled by moving a pinhole and corresponding interference patterns are recorded. Then the visibilities of the interference patterns are calculated for measuring the spatial coherence degree. Experimentally measured and theoretically calculated values of spatial coherence degree fit well. The measurement error is 3.8%. Experimental results show the method proposed here is effective, simple, and robust without any special optical elements.
Influence of pulling velocity on microstructure and morphologies of SCN-DC eutectic alloy
Authors: Bai Bei-Bei  , Lin Xin  , Wang Li-Lin  , Wang Xian-Bin  , Wang Meng  , Huang Wei-Dong  ,   State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an 710072, China
Published: December 2020

Eutectic solidification is very important in the development of new materials in which the periodic multiphase structures may have a remarkable or enhanced functionality. The morphology evolution during eutectic solidification is investigated experimentally using slab-geometry slides of succinonitrile-(D)camphor (SCN-DC) transparent organic eutectic material. By specifically focusing on the effect of pulling velocity on microstructure in directional growth, the temperature gradient and the thickness are kept the same in all the experiments. It is found that eutectic seeds first occur in the grain boundary channel or the specimen side-wall groove. And the growth of eutectic seeds is both parallel to the direction of temperature gradient and along the liquid/solid interface at the same time. At a low pulling velocity (0.064–0.44 μm/s), the macroscopic growth morphology is flat, and the inner microstructure is rod-shaped, which is parallel to the growth direction. It is obvious that the eutectic spacing becomes smaller with the increase of pulling velocity. At a high pulling velocity (0.67–1.56 μm/s), the macroscopic growth morphology becomes cellular. However, the inner microstructure is still rod-shaped, but its distribution is radially outward. And the eutectic spacing decreases as pulling velocity increases.
An improved back projection imaging algorithm for dechirped missile-borne SAR
Authors: Chen Si  , Zhao Hui-Chang  , Zhang Shu-Ning  , Chen Yong  ,   School of Electronic and Optical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
Published: December 2020

The range migration of missile borne synthetic apertare radar (SAR) is very difficult to correct using all the conventional imaging algorithms but the back projection algorithm; however, the large computation burden and the low efficiency are the key problems existing in its practical application. To solve the problems, an extended back projection imaging algorithm for the dechirped missile borne SAR is proposed. Firstly, a new signal model is built for the dechirped missile borne SAR, and the range compression is implemented in the range frequency domain. Secondly, the imaging region is divided into several stripes in range direction, and the raw echo data is back projected to each stripe for coherent integration by using the sub-aperture merging and image splitting technique. Finally, the entire SAR image can be obtained by combining the subimages of all the stripes. The validity of the proposed algorithm is demonstrated by the simulated and real SAR datasets. Testing results indicate that the extended algorithm is appropriate for achieving accurate dechirped missile borne SAR image. Moreover, it can be easily parallelized because the stripe imaging is independent of each other, so that can greatly decrease the computation burden, and improve the computation speed. The method introduced in this paper has important theoretical significance in realistic remote sensing, detection and recognition of military targets and precision guide.
Robust observer-based H control for nonlinear T-S fuzzy time-delay systems
Authors: Song Xiao-Na  , Liu Lei-Po  ,   Electronic and Information Engineering College, Henan University of Science and Technology, Luoyang 471023, China
Published: December 2020

This paper considers the design problem of observer-based H output feedback control over the nonlinear Takagi-Sugeno (T-S) fuzzy systems with distributed delays．Firstly, delay-dependent sufficient conditions satisfy the H performance, are given for the stability analysis in terms of non-strict linear matrix inequality; then, the equivalent linear matrix inequality stability conditions can be obtained. Based on this, the solvable of the observer-based H output feedback control problem is proposed. Finally, a numerical example is given to illustrate the effectiveness of the design approach here.
Data inversion technique for single Fabry-Perot etalon-based dual-frequency Doppler lidar
Authors: Shen Fa-Hua  , Sun Dong-Song  , Liu Cheng-Lin  , Qiu Cheng-Qun  , Shu Zhi-Feng  ,   Department of Physics, Yancheng Teachers University, Yancheng 224002, China;,   School of Space and Earth Science, University of Science and Technology of China, Hefei 230026, China
Published: December 2020

The effective transmittance of the Fabry-Perot (F-P) etalon in the case of the atmospheric backscatter light incidence is deduced. In the single F-P etalon-based dual-frequency Doppler lidar system, the wind retrieval accuracy with Rayleigh-induced effect for average method is analyzed quantitatively. A nonlinear iterative algorithm is proposed which can retrieve both wind speed and backscatter ratio, and its effectiveness is verified by simulation test. At the same time, the specific expressions of the radial wind speed error and backscatter ratio error are deduced. According to these expressions, the radial wind speed error and backscatter ratio error are simulated. The simulation results show that on the assumption that the total number of backscattering photons received by telescope is 50000, the radial wind speed measurement error decreases rapidly with the increase of backscatter ratio; when Rβ >1.2, the radial wind speed error is below 3 m/s within the wind speed measurement dynamic range of ±25 m/s; the backscatter ratio measurement error increases with the increase of backscatter ratio, but it is almost irrelative to the magnitude of radial wind; when Rβ<10, the backscatter ratio relative error is less than 13%.
Performance evolution process of machined surface of monocrystalline silicon micro/nanostructures
Authors: Hu Xing-Lei  , Sun Ya-Zhou  , Liang Ying-Chun  , Chen Jia-Xuan  ,   School of Mechatronics Engineering, Harbin Institute of Technology, Harbin 150001, China;,   Beijing Institute of Automatic Control Equipment, Beijing 100074, China
Published: December 2020

The machined workpiece has high mechanical storage energy because of the defect structures formed in nanocutting and their evolution from high energy state to the low energy state by adjusting atom positions automatically is called surface-energy aging. The effect of surface-energy aging on the surface properties of monocrystalline silicon workpiece is analyzed by Monte Carlo simulations of machined surface. It is shown that the surface-energy aging effect can increase the surface roughness and the degree of order of damaged layer, however reduce the residual stress and the average potential energy of workpiece. Amorphous silicon structure in metamorphic layer decreases and recrystallization phenomenon occurs in the surface-energy aging process. It is found that some β-Si phase structures and BCT5-si phase structures transform into the diamond cubic structure of Si in the surface-energy aging process. Surface-energy aging effect has a great influence on the surface properties of the machined surface of monocrystalline silicon workpiece, and can improve the mechanical properties of micro/nanostructures.
Optical transfer function of coherent field imaging based on deviation of receptors
Authors: Xiang Li-Bin  , Zhang Wen-Xi  , Wu Zhou  , Lü Xiao-Yu  , Li Yang  , Zhou Zhi-Sheng  , Kong Xin-Xin  ,   Academy of Optics and Electronics, Chinese Academy of Sciences, Beijing 100094, China;,   University of Chinese Academy of Sciences, Beijing 100049, China;,   Department of Precision Machinery and Precision Instrumentation, University of Science and Technology, Hefei 230027, China
Published: December 2020

According to the feature of receptor system of coherent field imaging technique, also known as Fourier telescope, the influence of the deviation of receptors on optical transfer function (OTF) of coherent field imaging technique is investigated, and the relation between OTF and optical distance mean square deviation of receptor is also derived, which indicates that the OTF of coherent field imaging technique is a negative index function of square of product of optical distance mean square deviation and frequency difference. It can provide theoretical basis of determining the accuracy of receptor system.
Thermodynamic study on two-step desorption of oxides on InAs(001) surface
Authors: Wei Wen-Zhe  , Guo Xiang  , Liu Ke  , Wang Yi  , Luo Zi-Jiang  , Zhou Qing  , Wang Ji-Hong  , Ding Zhao  ,   College of Science, Guizhou University, Guiyang 550025, China;,   School of Education Administration, Guizhou University of Finance and Economics, Guiyang 550004, China
Published: December 2020

Reflection high energy electron diffraction (RHEED) is used to monitor the two-step desorption of oxides on InAs(001) surface in the vacuum chamber, and the high temperature indium-assisted desorption processes of surface oxides under high arsenic pressure and low arsenic pressure are compared. The first step of two-step deoxidation method for InAs substrate is to heat the substrate slowly at high temperature. The second step is high temperature indium beam-assisted desorption of surface oxides. The RHEED patterns of sample at high temperature desorption of oxides show that the high temperature indium beam-assisted desorption of InAs surface oxide method could eventually clear residual oxide that the traditional slow heating method cannot remove. The scanning tunneling microscope images of sample after homogeneous epitaxial growth prove the viability of high-heat indium beam-assisted desorption of InAs surface oxide under high arsenic pressure. Finally, we analyse the mechanism of high-heat indium beam assisted desorption of surface oxides of substrate.
Ion beam etching for multilayer dielectric pulse compressor gratings with top layers of HfO2
Authors: Xu Xiang-Dong  , Liu Ying  , Qiu Ke-Qiang  , Liu Zheng-Kun  , Hong Yi-Lin  , Fu Shao-Jun  ,   National Synchrotron Radiation Laboratory, University of science and technology of China, Hefei 230029, China
Published: December 2020

Multilayer dielectric grating (MDG) is one of the key optical elements of high-power laser systems. To meet the need of MDGs for high-power laser systems, experimental investigation on MDG with a top layer of HfO2 has been carried out using Kaufman-type ion beam etcher. The optimal ion source conditions have been obtained by etching of HfO2 in pure Ar and Ar/CHF3 mixture plasmas. Compared with pure Ar plasma etching, better selectivity was achieved with Ar/CHF3. The redeposition of sidewalls effects are quite obvious during etching, which results in the increase in duty cycle of etched grating. As there is a distribution of etch rate along the direction normal to the scan movement, a special-shaped mask was made to be used as a substrate holder, which increases uniformity of the etched profile. In order to process repeatability, the ion source should be cleaned up, the cathode and neutralizer filament should be changed after etching process to full completion. Based on the above techniques, a number of MDGs have been achieved, each of which has a mean diffraction efficiency greater than 95%, a line density 1480 lines/mm, and on aperture up to 80 mm×150 mm. Experimental results agree fairly well with the designed, which provides a good reference for the large aperture MDGs ion beam etching.
Effect of concentration of heavy oxygen vacancy in rutile and anatase (TiO2) on electric conductivity performance studied by simulation and calculation
Authors: Hou Qing-Yu  , Wu Yun  , Zhao Chun-Wang  ,   College of Sciences, Inner Mongolia University of Technology, Hohhot 010051, China;,   Chemistry department, Inner Mongolia Vocational College of chemistry Engineering, Hohhot 010071, China
Published: December 2020

The pure and heavy oxygen vacancy for both rutile and anatase supercell models of TiO1.9375 were structured by using first-principles plane-wave ultrasoft pseudopotential method based on the density functional theory, the geometry optimizations, band structures, and density of states of these models were calculated. Results show that the volumes become greater for both heavy oxygen vacancy rutile and anatase, meanwhile, all of the stability, mobility, and conductivity of anatase supercell model of TiO1.9375 ore greater than the rutile supercell model, which are in agreement with the experimental results.
Effects of sensitive changing-lane rule on the off-ramp traffic system
Authors: Kang Rui  , Yang Kai  ,   Civil Aviation Flight University of China, Guanghan 618307, China;,   College of Computer Science, Sichuan University, Chengdu 610054, China
Published: December 2020

Based on the NaSh model, the rules of straight movement and lane change are defined while considering the change of driving behavior under the guidance of traffic signs at ramp; besides, a traffic model with sensitive lane change under the cellular automation is proposed. Furthermore, computer numerical simulation result indicates that the procedure of sensitive lane change can effectively reduce the lane change ratio of the straight moving vehicles, thus obviously it has an inhibitory effect on unnecessary lane change; what is more, the longer the sensitive lane change zone, the more effective the inhibitory function is. However, the traffic signs at ramp cannot be set as far as possible. Lower the lane change ratio is, shorter the sensitive lane change zone needed is. The traffic signs at ramp are set with proper distance according to the lane change ratio can effectively increase systematic traffic flow as well as the critical entrance probability.
Bifurcation phenomena in single-phase three-level inverters
Authors: Liu Hong-Chen  , Wang Yun  , Su Zhen-Xia  ,   School of Electrical Engineering and Automation, Harbin Institute of Technology, Harbin 150001, China
Published: December 2020

Compared with traditional two-level inverter, three-level inverter has the advantages of low output voltage harmonic distortion, and small switch voltage stress, so it attracts more and more attention in high power applications. In this paper, the bifurcation and chaos in a single-phase three-level inverter are studied. The one-dimensional discrete iterated mapping model under proportional control is established, and the stroboscopic maps in different periods of time are obtained. The bifurcation phenomena in the single-phase three-level inverter are studied when the proportional coefficient k, load resistance R, load inductance L and input voltage E are used as changing parameters. Effects of all these parameters on the system dynamical performances are analyzed on a slow scale using the bifurcation diagram and Lyapunov index spectrum. The bifurcation processes on a fast scale caused by changing values of proportional coefficient and load resistance are visually observed using folded diagram. Finally, the time-domain waveforms with different proportional coefficients are obtained by Matlab/Simulink, which corresponds with the theoretical analysis. The results show that the correct circuit parameters of single-phase three-level inverter are very important for its stable operation.
High-resolution digital holographic microscopy realized by small size CCD camera
Authors: Wang Hua-Ying  , Yu Meng-Jie  , Jiang Ya-Nan  , Song Xiu-Fa  , Zhu Qiao-Fen  , Liu Fei-Fei  ,   College of Science, Hebei University of Engineering, Handan 056038, China;,   School of Information and Electrical Engineering, Hebei University of Engineering, Handan 056038, China;,   College of Automation, Beijing Institute of Technology, Beijing 100081, China
Published: December 2020

In order to achieve high-resolution imaging by reducing the cost of digital holographic microscopy system, the recording and reconstruction process of image-plane digital holographic system (IPDHS) and its point spread function are analyzed. Then, the determination factor of lateral resolution of IPDHS is investigated. It is concluded that the dependence of lateral resolution of IPDHS on the photosensitive surface size of the recording device is very weak, which is completely different from the common knowledge that the lateral resolution of digital holographic imaging system can be improved by using large size recording device. Then the imaging characteristics of an IPDHS are analyzed. The results show that the information about the tested object can be completely recorded and reconstructed by image-plane digital holography, and that the lateral resolution of IPDHS is higher than that of pre-magnification digital holography. Two IPDHS with plane and spherical reference wave are built. The experimental results are in accordance with the theoretical analysis.
Optimal design of light trapping structure for broadband absorption enhancement in amorphous silicon solar cell
Authors: Jia Yu-Kun  , Yang Shi-E  , Guo Qiao-Neng  , Chen Yong-Sheng  , Gao Xiao-Yong  , Gu Jin-Hua  , Lu Jing-Xiao  ,   Key Laboratory of Materials Physics of Ministry of Education, School of Physical Engineering, Zhengzhou University, Zhengzhou 450052, China
Published: December 2020

Light trapping is one of the key issues to improve the light absorption and increase the efficiency of thin film solar cell. In this paper, a novel combined light trapping structure consisting of back one-dimensional (1D) Ag nano-grating and front conformal antireflective coating is proposed for amorphous silicon (α-Si) thin film solar cell. By a numerical simulation based on the finite element method, the effect of the combination on the light absorption of α-Si solar cell is investigated, and the Ag nano-grating parameters are optimized. The results show that the combined light trapping structure can enhance broadband absorption in thin-film solar cell. For the α-Si solar cell with the combined structure at P=600 nm, H=90 nm, and W=180 nm, the integrated absorption is enhanced by 103% under AM1.5 illumination at normal incidence in a wavelength range of 300–800 nm, and the photon absorption rate is increased by 300% in a long-wavelength range of 650–750 nm compared with the reference cell. We discuss the physical mechanism of absorption enhancement in different wavelength ranges from the electrical field amplitude distributions in the solar cells. In addition, the solar cell with the combined structure is much less sensitive to the angle of incident light.
OTTOCODIFICAÇÃO DE PEQUENAS BACIAS HIDROGRÁFICAS NA AMAZÔNIA
Authors: Santana Laila Rover , Blanco Claudio José Cavalcante , Pessoa Francisco Carlos Lira
Published: December 2020

A literatura apresenta algumas definições muito subjetivas para classificar pequenas bacias hidrográficas em função da área de drenagem. Isso ocorre, talvez, pelo menor interesse nessas bacias em relação às grandes e médias bacias hidrográficas. A motivação do presente estudo é identificar essas bacias na Amazônia, utilizando o método de Otto Pfafstetter. O método foi aplicado em um bacias hidrográficas obtidas pelo Modelo Digital de Elevação Hidrograficamente Condicionado (MDEHC), que utilizou imagens do Shuttle Radar Topography Mission (SRTM), com resolução de 90 m. A delimitação de pequenas bacias foi realizada partindo-se do nível 2 da ottocodificação disponibilizado pela Agência Nacional de Águas (ANA). Ao todo foram delimitadas 51.319 pequenas bacias, todas com áreas de drenagem menores ou iguais a 500 km². Assim, para se identificar pequenas bacias hidrográficas na Amazônia através do método de ottocodificação, é necessário aplicar o método até o nível 9.
Body mass index and peer victimization: A transactional model
Authors: Thakkar Niharika , van Geel Mitch , Malda Maike , Rippe Ralph C. A. , Vedder Paul
Published: December 2020

Past research has shown concurrent associations between adolescent's body mass index (BMI) and classroom bullying victimization experiences. The goal of this three‐wave longitudinal study is to examine a transactional model of associations between BMI and bullying victimization among adolescents in India. We investigate concurrent unidirectional and bidirectional relations between BMI and victimization. In a sample of 1238 students from nine schools (Grades 7–9; M‐ageT1 = 13.15, SD = 1.16) in Indore, India, we used self‐ and peer‐reports to measure bullying victimization in the classroom, and objective measurement of students' height and weight to collect data on adolescents' BMI, across three waves in one school year. Structural equational modeling was used to test transactional relations between BMI and bullying victimization. For self‐reported victimization, there was no concurrent or over time association between BMI and victimization for boys or girls in the present study. For peer‐reported victimization, we observed concurrent associations between BMI and victimization for boys and girls and a prospective relation where higher BMI corresponded to less victimization over time for boys. The study yielded mainly concurrent relations between BMI and victimization among adolescents in India. Results from western countries may not generalize to India.
Short‐Term Effects of Occupational Therapy on Hand Function and Pain in Patients With Carpometacarpal Osteoarthritis: Secondary Analyses From a Randomized Controlled Trial
Authors: Tveter Anne Therese , Østerås Nina , Nossum Randi , Eide Ruth Else Mehl , Klokkeide Åse , Matre Karin Hoegh , Olsen Monika , Kjeken Ingvild
Published: December 2020

Objective

To assess the short‐term effects of multimodal occupational therapy on pain and hand function in patients referred for surgical consultation due to first carpometacarpal (CMC1) joint osteoarthritis (OA).

Methods

In this randomized controlled trial, patients with CMC1 joint OA referred for surgical consultation at 3 rheumatology departments were randomized to 3 months multimodal occupational therapy (including patient education, hand exercises, orthoses, and assistive devices) or usual treatment (OA information). Pain was measured on a numeric rating scale from 0 to 10 (0 = no pain). Function included grip and pinch strength (Newtons), range‐of‐motion (palmar and CMC1 joint abduction [°]; flexion deficit in digits 2–5 [mm]), and self‐reported Measure of Activity Performance of the Hand (MAP‐Hand; range 1–4, 1 = no activity limitation) and short version of the Disability of the Arm, Shoulder, and Hand (QuickDASH; range 0–100, 0 = no disability). Between‐group difference was assessed with follow‐up values as dependent variables and group as an independent variable, adjusted for baseline values and time to follow‐up.

Results

Among 180 patients (mean ± SD age 63 ± 8 years; 81% women), 170 completed the short‐term follow‐up assessment (3–4 months after baseline). Compared to usual treatment, occupational therapy yielded significantly improved pain at rest (−1.4 [95% confidence interval (95% CI) −0.7, −2.0]; P < 0.001), pain following grip strength (−1.1 [−0.5, −1.7]; P = 0.001), grip strength (23.4 [95% CI 7.5, 39.3]; P = 0.004), MAP‐Hand score (−0.18 [95% CI −0.09, −0.28]; P = 0.001), and QuickDASH score (−8.1 [95% CI −4.6, −11.5]; P < 0.001).

Conclusion

The multimodal occupational therapy intervention had significant short‐term effects on pain, grip strength, and hand function in patients with CMC1 joint OA.
Synchrotron Sub‐μ X‐ray Tomography of Kirkendall Porosity in a Diffusion Couple of Nickel‐Base Superalloy and Nickel after Annealing at 1250 °C
Authors: Epishin Alexander , Camin Bettina , Hansen Lennart , Chyrkin Anton , Nolze Gert
Published: December 2020

Kirkendall porosity that forms during interdiffusion in a diffusion couple of nickel‐base superalloy CMSX‐10 with pure nickel is investigated. The diffusion experiments are conducted at a temperature of 1250 °C, where the strengthening γ′‐phase is partially dissolved. The porosity is studied by X‐ray sub‐μ tomography with a spatial resolution of about 0.353 μm3 at the European Synchrotron Radiation Facility (ESRF) in Grenoble, France. It is found that depending on the distance from the interface the Kirkendall pores take different shapes: octahedral, rounded pyramidal, drop shaped, dendritic, pear shaped, and joint shapes. Such a variety of pore morphologies indicates a complex multistage process of porosity nucleation and growth under vacancy supersaturation of different degrees. The experimental findings are interpreted on the basis of the results of diffusion modeling. It is shown that the kinetics of porosity growth is essentially influenced by the dissolution of the γ′‐phase.
Neuron‐Gated Silicon Nanowire Field Effect Transistors to Follow Single Spike Propagation within Neuronal Network
Authors: Delacour Cécile , Veliev Farida , Crozes Thierry , Bres Guillaume , Minet Julien , Ionica Irina , Ernst Thomas , Briançon-Marjollet Anne , Albrieux Mireille , Villard Catherine
Published: December 2020

Silicon nanowire field effect transistors (SiNW‐FETs) provide a local probe for sensing neuronal activity at the subcellular scale, thanks to their nanometer size and ultrahigh sensitivity. The combination with micropatterning or microfluidic techniques to build model neurons networks above SiNW arrays could allow monitoring of spike propagation and tailor specific stimulations, being useful to investigate network communications at multiple scales, such as plasticity or computing processes. This versatile device could be useful in many research areas, including diagnosis, prosthesis, and health security. Herein, SiNW‐based arrays enable to record electrical signals from matured neurons, such as local field potential and unitary spike within ex vivo preparations and hippocampal neurons grown on chip respectively. Furthermore, the ability to guide neurites above the sensor array during 3 weeks of cultures is demonstrated and the propagation of spikes along cells is followed. The SiNW‐FETs are obtained by a top‐down approach with complementary metal oxide semiconductor (CMOS) technology, showing the possibility to implement them at the manufacturing level. These results confirm further the potentiality of the approach to follow spike propagation over large distances and at precise locations along neuronal cells, by providing a multiscale addressing at the nano and mesoscales.
Hydrogel Microcapsules with a Thin Oil Layer: Smart Triggered Release via Diverse Stimuli
Authors: Jeong Hye‐Seon , Kim Eunseo , Nam Changwoo , Choi Yoon , Lee You‐Jeong , Weitz David A. , Lee Hyomin , Choi Chang‐Hyung
Published: December 2020

A hydrogel microcapsule with an intermediate thin oil layer is presented to achieve smart release of a broad range of cargoes triggered via diverse stimuli. A microfluidic technique is used to produce triple emulsion droplets with a thin oil layer that separates the innermost aqueous phase from the hydrogel prepolymer phase, which transforms into a hydrogel shell via photopolymerization. The intermediate oil layer within the hydrogel microcapsule acts as an effective diffusion barrier, allowing encapsulation of various small cargoes within a porous hydrogel shell until a stimulus is applied to destabilize the oil layer. It is demonstrated that diverse stimuli including chemical dissolution, mechanical stress, and osmotic pressure can be utilized to release the encapsulated cargo on‐demand. In addition, osmotic pressure and the hydrogel shell thickness can be independently tuned to control the onset time of release as well as the release behavior of multi‐cargo encapsulated hydrogel microcapsule. The release can be either simultaneous or selective.
Design and Experiment of Polyimide/Ti Wire Composite with the Interface Chemically Grafted through Carbon Nanotubes
Authors: Wang Hao , Jin Kai , Tao Jie
Published: December 2020

Herein, an efficient method is proposed to develop polyimide (PI)/titanium (Ti) wire composite with the interface chemically grafted through carbon nanotubes (CNTs). In order to reduce the research cost and blindness, nine strategies are designed herein to improve the interface compatibility of PI/Ti by using the simulation approach, and then an ideal solution is obtained to prepare the new composite material. The PI/Ti simulation model with interface grafted using different CNTs functionalized through ester and amide bonds is established. It is found that the interface cohesive energy can be improved by 276.7% by grafting COOH@MWCNTs through ester bond. Then, based on the simulation results, the PI/Ti wire composite with the interface chemically grafted through COOH@MWCNTs is prepared successfully, which exhibits an increase of 243.3% in interface shear strength (IFSS). Furthermore, the result also indicates that when the orientation of grafted COOH@MWCNTs is perpendicular to the Ti surface, its interface performance achieves the maximum with an IFSS increase of 301.3%. This method can also be used to improving the interface performance of Ti/Cf/polymerized monomer reactant (PMR) polyimide hybrid composite laminates (also known as TiGr).