bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect on the electronic structures and optical bandgaps of Ga-doped wurtzite TM0.125Zn0.875O(TM=Be, Mg)
Authors: Zheng Shu-Wen  , Fan Guang-Han  , Zhang Tao  , Pi Hui  , Xu Kai-Fang  ,   Laboratory of Nanophotonic Functional Materials and Devices, Institute of Opto-Electronic Materials and Technology, South China Normal University, Guangzhou 510631, China
Published: December 2020

The optimized structure parameters, electron density of states, energy band structures and optical bandgaps of the TM0.125Zn0.875O (TM=Be, Mg) alloys and Ga-doped TM0.125Zn0.875O are calculated and analyzed by using the ultra-soft pseudopotential approach of the plane-wave based upon density functional theory. The theoretical results show the Ga-doped TM0.125Zn0.875O materials are easily obtained and their structures are more stable. The Ga-doped TM0.125Zn0.875O are good n-type materials and their energy bandgaps are determined by Ga 4s states of the conduction band minimum and O 2p states of the valence band maximum. Compared with the TM0.125Zn0.875O alloys, the optical bandgaps of Ga-doped TM0.125Zn0.875O become wider due to the Burstein-Moss shift and many-body effects, which is consistent with previous experimental data. The Ga-doped TM0.125Zn0.875O materials are suitable as TCO films for the UV and deep UV optoelectronic device.
Models on threshold voltage/subthreshold swing and structural design of high-k gate dielectric GeOI MOSFET
Authors: Fan Min-Min  , Xu Jing-Ping  , Liu Lu  , Bai Yu-Rong  , Huang Yong  ,   School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, China
Published: December 2020

An analytical model on threshold voltage and subthreshold swing for high-k gate dielectric GeOI MOSFET (metal-oxide-semiconductor field-effect transistor) is established by considering the two-dimensional effects in both channel and buried-oxide layers and solving two-dimensional Poisson’s equation. The influences of the main structural parameters of the device on threshold voltage and subthreshold swing, and the short-channel effects, drain induction barrier lower effect and substrate-biased effect are investigated using the model, and the design principles and value range of the structural parameters are presented to optimize the electrical performances of the device. The simulated results are in good agreement with the TCAD simulated data, confirming the validity of the model.
High coercivity in Co79Zr18Cr3 magnet
Authors: Hou Zhi-Peng  , Su Feng  , Wang Wen-Quan  ,   College of Physics, Jilin University, Changchun 130023, China
Published: December 2020

The Co82-xZr18Crx (x=0, 2, 3, 4) alloys are produced by melt-spinning. It is found that a proper addition of Cr can improve the coercivity significantly and a maximum coercivity of 6.5 kOe is obtained in the Co79Zr18Cr3 ribbon after having been annealed at 600 ℃. X-ray diffraction and thermomagnetic analysis are employed to determine its phase composition. It is found that the sample is comprised of the single Co11Zr2 and the Cr atoms enter into its lattice. A significant enhancement in the magnetocrystalline anisotropy field of Co11Zr2 is observed. SEM investigations show a microstructure consisting of equiaxed grains whose average size is about 400-500 nm. The coercivity enhancement in the Co79Zr18Cr3 alloy is ascribed to the increase in Ha.
Structure and magnetic properties of perovskite manganites La2/3Sr1/3FexMn1-xO 3
Authors: Yang Hong  , Qi Wei-Hua  , Ji Deng-Hui  , Shang Zhi-Feng  , Zhang Xiao-Yun  , Xu Jing  , Lang Li-Li  , Tang Gui-De  ,   Hebei Advanced Thin Films Laboratory, Department of Physics, Hebei Normal University, Shijiazhuang 050024, China
Published: December 2020

Perovskite manganites with nominal composition La2/3Sr1/3FexMn1-xO3 (x=0, 0.1, 0.2, 0.3, 0.5) are prepared by the sol-gel method. The samples are treated three times at 773 K, 873 K and 1073 K, separately, in which processes the temperature is slowly increased. The X-ray diffraction patterns indicate that the samples have a single phase and perovskite structure each. The dimensions of the crystalline particles, lattice constants, cell volumes of the samples are calculated using the XPert HighScore Plus software. The magnetic properties are measured using a Quantum Design Physical Property Measurement System. The magnetic moments of the samples at 10 K decrease with the increase of Fe doping level x. The decreasing process can be divided to two ranges: one is from x=0 to x=0.2, in which range the average magnetic moment per formula decreases rapidly from 2.72 B to 0.33 B, while the Curie temperature decreases rapidly from 327 K to 95 K, i.e., it is reduced by 232 K; the other is from x=0.2 to x=0.5, in which range, however, the average magnetic moment per formula decreases slowly from 0.33 B to 0.05 B, while the Curie temperature decreases slowly from 95 K to 46 K, i.e., it is reduced only by 49 K. The experimental result that the magnetic moments of the samples decrease with the increase of Fe doping level may be explained as the fact that the magnetic moment direction of the Fe cations is opposite to those of Mn cations.
Experimental and theoretical study of tris-(8-hydroxyquinoline) aluminum (Alq3) photoluminescence enhanced by self-assembled silver films
Authors: Ye Song  , Wang Xiang-Xian  , Hou Yi-Dong  , Zhang Zhi-You  , Du Jing-Lei  ,   Department of Electrical Engineering and Electrical Automation, Chaohu University, Hefei 238000, China;,   School of Physical Science and Technology, Sichuan University, Chengdu 610064, China
Published: December 2020

Alq3 photoluminescences (PL) enhanced by self-assembled silver films are investigated experimentally and theoretically. The experimental results show that both the apparent enhancement factor (AEF) and the emission enhancement factor (EEF) of Alq3 PL increase with the increase of density of average 70 nm diameter silver nanoparticles on the substrate. The maxima of AEF and EEF are about 3.2 and 13, respectively. Based on the optical antenna theory, the theoretical maxima of both quantum efficiency enhancement factor and EEF of Alq3 PL are about 1.4 and 15, respectively. By comparing of the experimental results with the theoretical results, we can conclude that the near-field enhancement of silver nanoparticles makes a major contribution to Alq3 PL emission enhancement, and the emission enhancement is dependent on the Alq3-silver nanoparticle distance and the area coverage ratio of silver nanoparticles to substrate.
Optimization of metamaterial based weighted real-coded genetic algorithm
Authors: Chang Hong-Wei  , Ma Hua  , Zhang Jie-Qiu  , Zhang Zhi-Yuan  , Xu Zhuo  , Wang Jia-Fu  , Qu Shao-Bo  ,   College of Science, Air Force Engineering University, Xi’an 710051, China;,   Key Laboratory of Electronic Materials Research of the Ministry of Education, Xi’an Jiaotong University, Xi’an 710049, China
Published: December 2020

A weighted real-coded genetic algorithm is proposed in this paper, in allusion to the characteristics of optimizing designs of metamaterials, which have many parameters and parameters of different powers in metamaterial structure. The algorithm utilizing allele or double gene to change the power of one gene, develops the idea of weighted encoded binary coding. Compared with common real-coded based genetic algorithm, the weighted real-coded genetic algorithm adds artificial selection in it, it can not only accelerate the speed of convergence, but also improve the solution quality, especially for the design of large-scale and long computation time. In this paper, the algorithm is verified by optimizing a metamaterial absorber.
Cross-layer resource allocation in cognitive radio networks based on game theory
Authors: Wu Chun  , Jiang Hong  , You Xiao-Jian  ,   State Key Laboratory of Integrated Service Networks, Xidian University, Xi’an 710071, China;,   School of National Defense Science and Technology, Southwest University of Science and Technology, Mianyang 621000, China
Published: December 2020

In this paper, we propose a cooperative decoupling method and a cross-layer joint method for multi-layer resource allocation in multi-hop cognitive radio networks. In cooperative decoupling method, the task of path choosing is accomplished independently, and then the game of channel and power allocations is implemented. In cross-layer joint method, the three-layer resource of path, channel and power is allocated simultaneously by process of game. The heuristic principles of network layer, media access control layer and physical layer are employed synthetically in two methods. The degree of receiving interference and the degree of sending interference are adopted to assist path choosing. The Boltzmann exploration based on the width of permitting power is designed to select the channel and power. The means of replacement and elimination of long link or bottleneck link are proposed to further enhance network performance. The sequential game process instead of simultaneous game process is chosen because the former has better convergence property in current scenario, and the concrete process of game is provided. Moreover, the Nash equilibrium of the games and the complexity of the algorithms are analyzed and discussed. Simulation results show that the cooperative decoupling method and the cross-layer joint method have better performances in the number of success flows, the achievable data transmission rate and power consumption than the cooperative link game and the local flow game with simple decoupling.
Adaptive chaotic ant colony optimization-RD based gravity matching aided navigation
Authors: Wang Yue-Gang  , Wen Chao-Bin  , Zuo Zhao-Yang  , Yang Jia-Sheng  , Guo Zhi-Bin  ,   Second Artillery Engineering University, Xi’an 710025, China;,   Unit 96124 of the Chinese People’s Liberation Army, Tonghua 134000, China
Published: December 2020

To solve the problems of basic gravity aided matching algorithm, i.e., time consuming, low precision and inefficiency when the inertial navigation system (INS) has a large initial error, a real algorithm on adaptive chaotic ant colony optimization-RD is proposed by using modified ant colony algorithm in continuous space to approach an optimizing model. The search efficiency, noise immunity and matching probability are improved by adaptively adjusting pheromone, chaos adaptive manage of ant colony algorithm search strategy, parameter and local pheromone. Experiment shows that it is more robust to INS initial error, matching efficient and good real-time calculation.
Data fusaggregation algorithm based on dynamic minimal spanning tree routing protocol
Authors: Peng Hai-Xia  , Zhao Hai  , Li Da-Zhou  , Lin Chuan  ,   Institute of Information Science and Engineering, Northeastern University, Shenyang 110819, China
Published: December 2020

Large-scale geographic environmental monitoring and physical infrastructure for transferring and processing data cannot maintain the same growth rate with the monitoring scale, thus make the data gathering and processing under unreliable links, showing a kind of saturation flow state; and the ability of wireless sensor network (WSN) seemingly cannot be stabilized. On the other hand, though the calculation results from ideal network model are accurate enough, they deviate from the practical application greatly, hence the network users cannot adequately analyze and utilize the sensed data from industrial field network, and also cannot analyze the influence of network size and performance on data fusaggregation. Because of these, we will present the‘transitional region phenomenon'to be one of assumptions for industrial field simulation, and propose a data fusaggregation algorithm for the practical application on this basis, i.e. data fusaggregation algorithm based on reliability (R algorithm). When designing the R algorithm, as an example of sum operator, the lower limit η of reliability of appreciate aggregation sum result will be calculated by analyzing and synthesizing the result automatically. Then the aggregation sum result and the value of η will be sent to users together. In addition to providing the summary information from the monitored area to users, R algorithm also provides the parameter η as the judgment of information reliability to facilitate users to do further handling of aggregation results and improve the WSN sensing performance. Simulation results describe the changing rule of reliability η caused by unreliable links from the signal-to-noise ratio in transitional region, and discuss the network influence of size and performance on reliability η, with the increase of network operation cycles and network scale, when the value of reliability η becomes gradually close to 0. And this provides theoretical foundations and empirical formulas for WSNs from theoretical model to practical industrial application.
Emergence of scaling in hypernetworks
Authors: Guo Jin-Li  , Zhu Xin-Yun  ,   Business School, University of Shanghai for Science and Technology, Shanghai 200093, China;,   Center for Supernetwork Research，University of Shanghai for Science and Technology, Shanghai 200093, China
Published: December 2020

This paper proposes a unified model for hypernetworks and complex networks, and studies the evolution mechanisms of scale-free hypernetworks and the topological properties of the hypernetwork. We have analyzed the proposed model and calculated the stationary average hyperdegree distribution of the hypernetwork by using a Poisson process theory and a continuous technique. The analytical result agrees well with the simulation. It is shown that the hyperdegree distribution of the dynamic model follows a scale-free law. This paper not only integrates the hypernetwork model, in which one new node forms an edge with some old nodes, and the hypernetwork model, in which some new nodes form an edge with one old node, but also integrates the scale-free model in complex networks.
Studies on vibration response and energy harvesting of elastic-supported bistable piezoelectric cantilever beams
Authors: Gao Yu-Ji  , Leng Yong-Gang  , Fan Sheng-Bo  , Lai Zhi-Hui  ,   School of Mechanical Engineering, Tianjin University, Tianjin 300072, China;,   Key Laboratory of Mechanism Theory and Equipment Design of Ministry of Education, Tianjin University, Tianjin 300072, China
Published: December 2020

Based on the results of study on conventional rigid support nonlinear energy harvesters, in this paper, we conceive a kind of structure with an elastic-supported external magnet, for keeping the system in a state of bistable oscillation due to low-intensity excitations. Thus, an efficient electromechanical energy conversion can be accomplished. Studies show that the elastic-supported nonlinear energy harvesting systems do not need real-time adjustment of magnet spacings to meet varying-intensity random excitation vibrations. This structure helps to better satisfy the variable-intensity random excitation source, consequently it achieves efficiently electromechanical energy conversion.
Risk analysis on long inclined-shaft construction in coalmine by TBM techniques based on multiple variables chaotic time series
Authors: Hou Gong-Yu  , Liang Rong  , Sun Lei  , Liu Lin  , Gong Yan-Fen  ,   School of Mechanics and Civil Engineering, China University of Mining & Technology (Beijing), Beijing 100083, China
Published: December 2020

Multi-variable chaotic time series are used to predict the long inclined-shaft construction in coalmine construction by TBM techniques, and principal component analysis (PCA) is used to determine the main factors that impact risk (shield) of the long inclined-shaft construction in coalmine by TBM techniques. Phase space of risk time series for construction by TBM are reconstructed; time delay and embedding dimension are determined. Maximum Lyapunov indexes of risk are obtained by using small data quantity method; it is found that the time series have characteristics of chaos. Prediction model is established using the combination of first-order local method and double hidden layer neural network. Simulation experiments show that the combined model has a strong ability of prediction and achieves better effect. As a result, it provides a new way for long inclined-shaft construction in coalmine by TBM techniques.
Collimated electrons generated by intense laser pulse interaction with cone-structured targets using particle simulation
Authors: Wu Feng-Juan  , Zhou Wei-Min  , Shan Lian-Qiang  , Li Fang  , Liu Dong-Xiao  , Zhang Zhi-Meng  , Li Bo-Yuan  , Bi Bi  , Wu Bo  , Wang Wei-Wu  , Zhang Feng  , Gu Yu-Qiu  , Zhang Bao-Han  ,   Science and Technology on Plasma Physics Laboratory, Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900, China;,   Joint Laboratory for Extreme Conditions Matter Properties, Southwest University of Science and Technology, Mianyang 621010, China
Published: December 2020

Generation and propagation of fast electron bunches from interaction of short, ultra intense laser with cone-sandwich target are investigated by PIC (particle-in-cell) simulation. Results are compared with those in the interaction of the same laser parameters with cone-channel target, cone-wire target and cone target. Fast electrons generated by the interaction of intense laser with cone-sandwich target can be effectively collimated and propagated by the quasi-static strong magnetic field generated by the material surface of different densities. Compared with the other three cone-structured target, the more number and the higher energy of the fast electrons are generated by cone-sandwich target. This can well improve the energy conversion efficiency of the laser to fast electrons and the quality of fast electron bunches, which are favorable for the fast ignition energy deposition.
Statistical characteristics and variation of speckle intensity in deep fresnel diffraction region
Authors: Song Hong-Sheng  , Zhuang Qiao  , Liu Gui-Yuan  , Qin Xi-Feng  , Cheng Chuan-Fu  ,   School of Science, Shandong Jianzhu University, Jinan 250101, China;,   College of Physics and Electronics, Shandong Normal University, Jinan 250014, China
Published: December 2020

Based on the coherent superposition principle of direct-transmited light with the Gaussian speckle field, and also with the Kirchhoff approximation, the speckle in the deep Fresnel diffraction region is investigated. Expressions of speckle field in the deep Fresnel diffraction region, and the probability density of intensity, and contrast are obtained. In the deep Fresnel diffraction region of different scattering distance the variation of speckles is simulated with the height distribution data of random scattering surface measured by atomic force microscopy, and the curves of these two statistic functions are drawn. Combining the theory with the simulation, characteristics of these two statistic functions, the effect of the fraction of the direct transmit light intensity as well as their variations with the scattering distance are discussed.
Influence of filling factor on far-field intensity distribution in coherent beam combination
Authors: Tan Yi  , Li Xin-Yang  ,   Key Laboratory on Adaptive Optics, Chinese Academy of Sciences, Chengdu 610209, China;,   Institute of Optics and Electronics, Chinese Academy of Sciences, Chengdu 610209, China;,   University of Chinese Academy of Sciences, Beijing 100049, China
Published: December 2020

Theoretical analysis on the far-field diffraction of the coherent beam combination (CBC) is presented. An introduction is given to the definitions of filling factor and evaluation parameter of CBC. Based on the theoretical mode and definition, the influence of filling factor on far-field intensity distribution and the relationship between evaluation parameter and filling factor are theoretically described in detail. It is found that the filling factor influences far-field intensity distribution through space modulation factor. Results also indicate that SR is a constant which has not connection with the filling factor, and CR is of a linear relation with filling factor, and NACL has little connections with filling factor, and RCL varies approximately linearly with the square of filling factor, and PIB decreases when filling factor increases in general. If we make the filling factor larger than √2/2, more than half of the best values of RCL and PIB may be obtained.
Generation of cylindrical vector beams based on metasurface
Authors: Yi Xu-Nong  , Li Ying  , Liu Ya-Chao  , Ling Xiao-Hui  , Zhang Zhi-You  , Luo Hai-Lu  ,   College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China;,   Laboratory for Micro/Nano Optoelectronic Devices of Ministry of Education, Hunan University, Changsha 410082, China;,   College of Physics and Electronic Information Engineering, Hubei engineering University, Xiaogan 432000, China
Published: December 2020

A method of generating cylindrical vector beams based on metasurface is presented in this paper. The metasurface is a fused silica with a space-variant non-periodic grating which is written by laser. The non-periodic grating induces a space-variant effective birefringence that modulates the space distribution of polarization state. It is shown that an incident linearly polarized light can be converted to a cylindrical vector beam by the method of Jones matrix. We can obtain an arbitrary cylindrical vector beam on the equator of the higher-order Poincaré sphere. A simple and efficient experimental system is established with a metasurface. Experimental results are in agreement with the theoretical analysis.
Spontaneous emission from a two-level atom in a dynamic photonic crystal with an isotropic disoersion relation
Authors: Xing Rong  , Xie Shuang-Yuan  , Xu Jing-Ping  , Yang Ya-Ping  ,   Ministry of Education Key Laboratory of Advanced Microstructure Materials, School of Physics Science and Engineering, Tongji University Shanghai 200092, China
Published: December 2020

The spontaneous emission of a two-level atom, located in an isotropic photonic crystal with dynamically modulated photonic band edge, has been studied. When the photonic band edge is modulated with step functions or triangle functions, the evolution of atomic population on the upper level has been discussed. When the photonic band edge is modulated with step functions, the dynamics of atomic population depends not only on the detuning value of the atomic transition frequency from the band edge, but also on the time point of stepping. With the different time point of stepping, the dynamics of atomic population after stepping is different. When the photonic band edge is modulated with triangle functions, the atomic population oscillates quasi-periodically while decaying in general. The oscillation frequency, peak and valley values, and the decaying rate of oscillation can be modulated by choosing the frequency and initial phase of triangle functions.
Experimental features and mathematical model of pedestrian evacuation from a room with two exits
Authors: Yu Er-Dong  , Wu Zheng  , Guo Ming-Min  ,   Department of Mechanics and Engineering Science, Fudan University, Shanghai 200433, China
Published: December 2020

A set of experimental schemes of pedestrian evacuation from a room having two exits is proposed and applied to experiments. Some quantitative results of evacuation time varying with the number of pedestrians in different circumstances are obtained from the video recordings. The concept of attraction domain of a two-exit room is established. It is proved that the boundary curve of attraction domain of the smaller exit is always a circular arch, by which the mechanism of arch formation near an exit can be illustrated. Compared with the passenger evacuation procedure in a subway waiting hall, we have established a quadratic function model of evacuation time which can fit the measured data well for various cases. The evacuation time increases linearly with the number of people without waiting, and increases as a quadratic function of the number of people after the formation of a waiting region. It is also found that the expression is affected by the width of exit more sensitively than in other well-known models.
The flow and heat transfer characteristics of double droplets impacting on flat liquid film
Authors: Guo Ya-Li  , Wei Lan  , Shen Sheng-Qiang  , Chen Gui-Ying  ,   School of Energy and Power Engineering, Dalian University of Technology, Dalian 116024, China
Published: December 2020

A coupled level set and volume of fluid (CLS-VOF) method is applied to simulate the process of double droplets which continuously impact on a hot liquid film on a wall of constant temperature, and the evolution processes after the double droplets impinge on the hot flat liquid film are studied. Influences of vertical spacing between the two droplets, impact velocity, film thickness and droplet diameter on the flow and heat transfer characteristics are discussed. It is found that the average heat flux density of the wall increases with the rise of impact velocity. The influences of vertical spacing between the two droplets, droplet diameter, and liquid film thickness on the average heat flux density are small, but they have an important effect on the distribution of heat flow density in the impact area and the border area.
Study on multi-beam superposition using complementary polarization control plates
Authors: Li Ze-Long  , Zhong Zhe-Qiang  , Zhang Bin  ,   College of Electronics and Information Engineering, Sichuan University, Chengdu 610064, China
Published: December 2020

In order to meet the requirement for uniform irradiation on the target in inertial confinement fusion, a schemie is proposed for achieving the depolarized superposition of multi-beams and further improving the uniformity of the focus spot by using complementary polarization control plates to change the polarization state of the beam. A physical model of multi-beam transformation by complementary polarization control plates is built up, and the mechanism how complementary polarization control plates affect the polarization characteristics of the focus spot is analyzed theoretically. The polarization properties and uniformity of the focus spot are compared for the two cases: viz the complementary polarization control plates and the un-complementary polarization control plates. Furthermore, the selection of elements of polarization control plates is discussed. Results show that after beams propagating through the complementary polarization control plates, the focal spot is not completely polarized but mixed randomly with various kinds of partially polarized states. Compared with the un-complementary polarization control plates, the complementary polarization control plates can achieve better depolarization effect on focus plane, resulting in the degree of polarization dropping to below 0.2, and thus achieving the effective improvement of intensity uniformity. When the complementary polarization control plates are utilized, the number of elements of polarization control plates has little effect on the polarization characteristics of the spot, but it can influence the intensity uniformity to some extent. Consequently, the number of elements of polarization control plates should be chosen appropriately in practical application.
Particle-in-cell simulation on surface-wave discharge process influenced by gas pressure and negative-biased voltage along ion sheath layer
Authors: Chen Zhao-Quan  , Yin Zhi-Xiang  , Chen Ming-Gong  , Liu Ming-Hai  , Xu Gong-Lin  , Hu Ye-Lin  , Xia Guang-Qing  , Song Xiao  , Jia Xiao-Fen  , Hu Xi-Wei  ,   College of Electrical & Information Engineering, Anhui University of Science and Technology, Huainan 232001, China;,   State Key Laboratory of Advanced Electromagnetic Engineering and Technology, Huazhong University of Science and Technology, Wuhan 430074, China;,   State Key Laboratory of Structural Analysis for Industrial Equipment, Dalian University of Technology, Dalian 116024, China
Published: December 2020

Due to surface electromagnetic waves propagating along the dielectric-plasma interface, the application of surface-wave plasma (SWP) is limited in view of the fact that it is very difficult to realize metal sputtering by using negative-biased voltage in traditional SWP sources. Recently, this problem is overcome by a type of SWP source based on the guided wave in ion sheath layer driven by negative-biased voltage. And the plasma heating mechanism is originated from gas discharges excited by the local-enhanced electric field of surface plasmon polariton (SPP). However, the best discharge condition is not obtained because the influence factors affecting the discharge process studied is not clear. In this paper, the discharge mechanism of SWP ionization process influenced by gas pressure and negative-biased voltage along the ion sheath layer is investigated. The simulation method is by means of combining particle-in-cell (PIC) with Monte Carlo collision (MCC). Simulated results suggest that the values of negative-biased voltage and gas pressure can influence the thickness of ion sheath layer, the excitation of SPP, and the spatio-temporal conversion of wave mode, which further induces the different discharge performances. Moreover, the discussed analysis states that a better discharge performance can be obtained when approximately a negative-biased voltage of -200 V and a gas pressure of 40 Pa applied.
Simulation on similarity law of glow discharge in scale-down gaps of rod-plane electrode configuration
Authors: Fu Yang-Yang  , Luo Hai-Yun  , Zou Xiao-Bing  , Wang Qiang  , Wang Xin-Xin  ,   Department of Electrical Engineering, Tsinghua University, Beijing 100084, China
Published: December 2020

A fluid model of direct-current (DC) discharge in argon atmosphere between the gaps of rod-plane electrode configuration was established, and the discharge models of two geometrically similar gaps were solved using the finite-element method, respectively. The dimension ratio of the gaps was set as 10:1, and the gas pressure was ～133.3 Pa for the prototype and ～133 Pa for the scale-down gap; to the gaps the same DC voltages were applied. Voltage-current characteristics, as well as the physical discharge parameters (such as electric potential, electric field, electron density, ion density, and electron temperature) were obtained. Relations between parameters of the two gaps were investigated according to the theoretical relations derived by similarity law. Simulation results show that the discharge type in the two similar gaps is verified as a normal glow discharge; the parameter relations are in good agreement with the similarity law, and the working points of discharges are identical in similar gaps with the same applied DC voltage. This study could offer theoretical instruction in extrapolating the discharge properties for similar gaps.
On-line measurement on surface electric field of insulator in vacuum based on Kerr effect
Authors: Liu Wei-Li  , Zou Xiao-Bing  , Fu Yang-Yang  , Wang Peng  , Wang Xin-Xin  ,   State Key Laboratory of Power System, Department of Electrical Engineering, Tsinghua University, Beijing 100084, China
Published: December 2020

Kerr effect is defined as an electro-optical physical phenomenon, in which the testing laser can change its polarization state as passing through a Kerr medium stressed by applied field. In this work, an on-line measurement system based on Kerr effect is established to investigate the surface electric field of insulator stressed by nanosecond HV pulse in vacuum which include a HV pulse source, YAG laser, synchronous controlling apparatus, Kerr cell & insulator sample, optical phase shift detecting subsystem. According to comparison experiments, the distortion of insulator surface electric field caused by surface charging is observed. And a time-resolution measurement on this field distortion is also performed.
Luminescence characteristics of PVK doped with red-emitting quantum dots
Authors: Liu Zhi-Min  , Zhao Su-Ling  , Xu Zheng  , Gao Song  , Yang Yi-Fan  ,   Institute of Optoelectronics Technology, Beijing Jiaotong University, Key Laboratory of Luminescence and Optical Information (Beijing Jiaotong University), Ministry of Education, Beijing 100044, China
Published: December 2020

Multilayer electroluminescent devices with a system in which red-emitting quantum dots doped PVK serves as the active layer is fabricated through non-treatment process, the device structure being ITO/PVK:QDs/Alq3/Al. Measuring the emission spectra and electrical characteristics of the devices we study the effect of different QDs doping concentration (mass fraction), and propose some possible solutions to optimize the PVK:QDs system after taking pure QDs for comparison. Experimental results show that changing QDs doping concentration would bring significant impact on the electroluminescence (EL) spectra, current density, brightness, and the stability of devices. When QDs doping concentration is low, we will mainly see the light of Alq3; when QDs doping concentration is 20%, saturated pure red light emission is observed and it is brighter than other devices. However, when the doping concentration is high, a slight red shift occurs in the EL spectra, and the performance of the device gets worse. With a suitable doping concentration, the PVK:QDs may increase the stability of devices.
Influence of external magnetic field on properties of aluminum-doped zinc oxide films prepared by RF magnetron sputtering
Authors: Chen Ming  , Zhou Xi-Ying  , Mao Xiu-Juan  , Shao Jia-Jia  , Yang Guo-Liang  ,   School of Material Engineering, Shanghai University of Engineering Science, Shanghai 201620, China
Published: December 2020

Al-doped ZnO (AZO) transparent conductive oxide films were prepared by RF magnetic sputtering. An external magnetic field was applied to the traditional magnetron sputtering system. The influence of the external magnetic field on the crystalline structure, surface topography and photoelectric properties of the AZO transparent conductive film have been studied. XRD diffraction patterns show that under the same processing condition, the intensity of (002) diffraction peak is significantly increased with the external magnetic field, suggesting a higher degree of c-axis preferred orientation. Scanning electron microscope shows that the external magnetic field can enlarge the grain size and density of films; the surface topography of the AZO films deposited without an external magnetic field is wormlike. Deposition rate and square resistance test results show that in an external magnetic field, the deposition rate will increase from 13.04 nm/min to 19.93 nm/min, and the sheet resistance reduce to 12.88 Ω /□ from 30.74 Ω /□ at a sputtering time of 90 min. Optical transmittance spectra shows that the average transmittance of all the films in visible light spectrum is over 85% when the sputtering time is not more than 60 min, while the external magnetic field has little effect on the transmittance of the films, but making a larger blue shift of the absorption edge. Ansys software is used to simulate the two-dimensional magnetic field distribution above the target. Results show that the intensity of the horizontal magnetic field and the uniformity of it are improved by the external magnetic field, the secondary electrons near the target are tightly bound, leading to a much larger target current intensity. So the deposition rate, surface topography and photoelectric properties of the AZO films are improved.
Fabrication and application of ordered Si nanopore array induced by Au
Authors: Wang Hai-Peng  , Ke Shao-Ying  , Yang Jie  , Wang Chong  , Yang Yu  ,   Institute of Optoelectronic Information Materials, Yunnan University, Kunming 650091, China
Published: December 2020

Size-controlled Si nanopore array with a pore size less than 100 nm is fabricated on Si (100) substrates by using monolayer self-assembled and KOH anisotropic wet etching technique. Morphology and structure of the pores are characterized by SEM and AFM. Results show that a large area of defect-free polystyrene (PS) monolayer film can be obtained when the volume ratio of PS solution to methanol solution is 9:11. A larger volume ratio or a smaller volume ratio will induce similar bilayer structure and defects (point and line) in the PS film, respectively. The lateral size and depth of the nanopore will increase with the etching time, and its morphology will change from circular to inverted pyramid type gradually. But the orderly arranged structure will be destroyed as the etching time is over 10 min. On the other hand, ordered Ge/Si nanoislands and nanorings will be grown on nanopore-patterned Si (100) substrates (inverted pyramid and circular nanopores, respectively) by ion beam sputtering. In addition, reasonable interpretations have been proposed for the formation mechanism of the ordered Ge/Si nanostructure.
Valley current mode pulse train control switching converter and its energy model analysis
Authors: Sha Jin  , Xu Jian-Ping  , Liu Shu-Han  , Zhong Shu  ,   Key Laboratory of Magnetic Suspension Technology and Maglev Vehicle, Ministry of Education, School of Electrical Engineering, Southwest Jiaotong University, Chengdu 610031, China
Published: December 2020

Pulse train (PT) control technique is a novel discrete control technique for switching converter operating in discontinuous conduction mode (DCM). When the inductive energy storage is not zero, the low-frequency oscillation phenomenon may occur in PT controlled switching converters operating in continuous conduction mode (CCM). The low-frequency oscillation phenomenon will seriously affect the steady and transient performances of switching converters. In order to solve this problem, valley current mode pulse train (VCM-PT) control technique, which extends the application range from DCM to CCM, is proposed in this paper. The energy model of VCM-PT controlled switching converter is derived and compared with the energy model of PT controlled switching converter. Result indicates that the VCM-PT controlled CCM switching converter has the same energy transfer mode as the traditional PT controlled DCM switching converter and can eliminate fundamentally the low-frequency oscillation phenomenon.
High voltage direct current additional reduced-order controller design based on improved projective control
Authors: Li Bao-Hong  , Zhang Ying-Min  , Li Xing-Yuan  , Liu Tian-Qi  , Zhao Rui  ,   Electrical Engineering and Information College of Sichuan University, Chengdu 610065, China
Published: December 2020

A new reduced-order controller design method based on improved projective control is introduced. And the low-frequency oscillations can be suppressed by high voltage direct current additional controller through this method. The system reduced mode and relative oscillation frequencies are obtained through TLS-ESPRIT algorithm. Then the controller is designed by improved projective control, after the pole-placement method is applied to obtain a state-feedback matrix. The traditional pole-placement controller based on observer is compared with the projective controller at the same time. The advantages of lower order, stronger robustness and better control effect have been proved through simulation.
Quantum mechanical state equation for describing evolution of projects of financial investment
Authors: Da Cheng  , Fan Hong-Yi  ,   Department of Materials Science and Engineering, University of Science and Technology of China, Hefei 230026, China
Published: December 2020

This paper proposes a quantum mechanical state equation for describing evolution of projects of financial investment, while the parameters of this equation well simulate the fundamental elements of financial market, including investment (input), assets loss (assets decrease), assets increase and income (output), the quantum mechanics operators involved in this equation also can reflect the dynamic process and characteristics of the project, so the equation can be taken as the evolution model of a kind of financial investment projects in the market. The entangled state representation is introduced to solve this equation and its solution is obtained in an infinite operator-sum form, which exhibits the link between the initial state and final state, i.e., the dynamic process of the financial investment project. As an example, we derive the evolution law of a pure investment project in financial market, which conforms with the evolution trend of the market. In solving the equation we also find a new state which we name it as the binomial-negative binomial entangled state. Throughout the discussions we make full use of Dirac's symbolic method and the technique of integration within an ordered product (IWOP) of operators.
Spatial distribution and seasonal variation characteristics of global atmospheric moisture recycling
Authors: Su Tao  , Lu Zhen-Yu  , Zhou Jie  , Hou Wei  , Li Yue  , Tu Gang  ,   College of Atmospheric Sciences, Lanzhou University, Lanzhou 730000, China;,   National Climate Center, Laboratory for Climate Studies of China Meteorological Administration, Beijing 100081, China;,   Tianshui Meteorological Bureau, Tianshui 741000, China;,   Institute of Meteorological Science of Jilin Province, Changchun 130062, China
Published: December 2020

This paper makes use of new definitions of moisture recycling to study the complete process of global moisture feedback. An accounting procedure based on ERA-Interim reanalysis data is used to calculate moisture recycling ratios. Furthermore, the spatial distribution and seasonal variation characteristics of global moisture recycling are analyzed. Results indicate that: a) Precipitation recycling ratio in different regions show distinct patterns. It is indicated that the dependences of precipitation in different regions on moisture transport are different. b) Spatial distribution of precipitation recycling ratio and evaporation recycling ratio are in good agreement over the lands, but show significant difference over the oceans. c) Seasonal variation characteristics of global moisture recycling ratio are significant, which are stronger in the Northern Hemisphere than in the Southern Hemisphere. d) Main oceanic sources are dominant over continental moisture recycling, and most of the evaporation is transported to other regions by advection. e) Regional moisture recycling ratio not only depends on the factors such as time, location, and shapes of the regions, but also the regional horizontal scale. The moisture recycling ratio curve rises as the regional horizontal scale increases. It is computed that, on the average, precipitation recycling ratio and evaporation recycling ratio of Chinese mainland are respectively about 32.6% and 44.9%; the main source of rainfall in China is moisture evaporated over the South China Sea, the Bay of Bengal, the Arabian Sea and the Western Australia Ocean. The atmospheric moisture recycling model in this paper is based on the atmospheric water balance equation, in terms of good mathematical and physical theory, hence the results are credible.
Liquid-liquid phase segregation process of Fe50Cu50 melt by molecular dynamics simulation
Authors: Qi Yu  , Qu Chang-Rong  , Wang Li  , Fang Teng  ,   School of Mechanical and Electrical and Information Engineering, Shandong University at Weihai, Weihai 264209, China
Published: December 2020

Molecular dynamics simulation based on the newly developed embedded atom method has been performed to explore the microstructure of liquid Fe50Cu50 alloy. The results show that coordination numbers (CNs) of Fe-Fe and Cu-Cu for Fe50Cu50 melt gradually increase with relaxation time increasing, and they are 9.9 and 9.3 respectively as the liquid is in an equilibrium state; while the CN of heterogeneous atomic pairs Fe-Cu gradually decreases, and it is about 4.6. The correlation length (CL) extracted from Bhatia-Thornton (B-T) structure factor increases with relaxation time increasing. Both CN and CL indicate that the Fe50Cu50 melt exhibits liquid-liquid (L-L) phase separation. The interconnected type of structure can be observed in the Fe50Cu50 melt at the early stage, then the heterogeneous atomic pairs separate gradually with time going by, the Fe-rich and Cu-rich structure are formed, which shows the characteristics of spinodal decomposition. By comparison, the atom snapshot of Fe75Cu25 melt is also visualized in the paper, and the finding indicates that the smaller number difference between Fe atom and Cu atom may lead to the stronger L-L phase separation, as a result of shorter time to reach stable layer-like structure. Our studies mentioned above characterize L-L phase separation of metallic liquid on the atomic scale.
Scattering quantum walk search algorithm on star graph
Authors: Liu Yan-Mei  , Chen Han-Wu  , Liu Zhi-Hao  , Xue Xi-Ling  , Zhu Wan-Ning  ,   School of Computer Science and Engineering, Southeast University, Nanjing 210096, China;,   Key Laboratory of Computer Network and Information Integration(Southeast University), Ministry of Education, Nanjing 210096, China
Published: December 2020

Quantum walk is a typical quantum computing model which is receiving significant attention in recent years from theory researchers. In this paper, we prove that the two major formulations for discrete quantum walks, coined and scattering, are unitarily equivalent on star graph. We then propose a new quantum search algorithm on star graph based on the scattering quantum walk. It is shown that the temporal complexity of the algorithm is the same as that in Grover algorithm, but success probability is greater than that in Grover algorithm when the objects are more than one third of total items.
Entanglement evolution of three interacting twolevel atoms within a common environment
Authors: Feng Ling-Juan  , Xia Yun-Jie  ,   Shandong Provincial Key Laboratory of Laser Polarization and Information Technology, Department of Physics, Qufu Normal University, Qufu 273165, China
Published: December 2020

Entanglement dynamical evolution of three two-level atoms coupled to a common environment is investigated. We utilize the tripartite negativity to quantify entanglement and analyze the effect of the initial state, pairwise dipole-dipole interactions on the entanglement dynamical properties of the system by means of numerical calculations. Results show that a novel quantum interference can be controlled by the relative phase of initially entangled states of the atoms. And the excited-state population can be trapped in the long time limit. Besides, the tripartite entanglement can be enhanced by choosing the appropriate conditions.
Investigation on stable structures of Au-Pd alloy nanoparticles with high-index facets
Authors: Shao Gui-Fang  , Zheng Wen-Xin  , Tu Na-Na  , Liu Tun-Dong  , Wen Yu-Hua  ,   School of Information Science and Engineering, Xiamen University, Xiamen 361005, China;,   Institute of Theoretical Physics and Astrophysics, Department of Physics, Xiamen 361005, China
Published: December 2020

Based on the Monte Carlo simulation method, this paper employs the tight-binding potentials and the quantum-corrected Sutton-Chen type many-body potentials to investigate the stable structure, the distribution of surface atoms, the core-shell distribution, and the chemical short-range order parameter of tetrahexahedral Au-Pd nanoparticles. Different sizes and different Au contents are considered. Our results show that the surface atom distribution exhibits the same trend for the two types of potentials, that is, Au atoms tend to segregate on the surface while Pd atoms prefer to occupy the inner sites, this is beneficial to lowering the total energy of the structure. Nanoparticles are always present in a core-shell structure for small Au content. With increasing Au content, the Au-Pd nanoparticles will tend to form an onion-like multi-shell structure for the tight-binding potentials. The degree of the segregation of Au-Pd nanoparticles at the quantum-corrected Sutton-Chen type potentials is higher than that for the tight-binding potentials.