bluuebunny/crossref_metadata_2025 huggingface dataset:
Simulated annealing reconstruction of LiCoO2 cathode microstructure and prediction of its effective transport properties
Authors: Wu Wei  , Jiang Fang-Ming  , Zeng Jian-Bang  ,   Key Laboratory of Renewable Energy of Chinese Academy of Sciences, Laboratory of Advanced Energy Systems, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640, China;,   University of Chinese Academy of Sciences, Beijing 100049, China
Published: December 2020

Reconstruction and characterization of the porous composite electrode via experimental and numerical approaches is one of the most important ingredients of mesoscopic modeling. It is also the basis and prerequisite for bottom-to-up design and optimization of electrode microstructure. In the present work, a simulated annealing approach is employed to reconstruct the LiCoO2 cathode of a commercial Li-ion battery. Important statistical characteristic parameters of the real LiCoO2 cathode, such as porosity or component volume fraction, the real size distribution curve of LiCoO2 particles, which are taken from experimental data or extracted from the source materials used to fabricate the cathode, are used to regulate the reconstruction process. The reconstructed electrode evidently distinguishes the three individual phases: LiCoO2 as active material, pores or electrolyte, and additives. An extensive characterization is subsequently performed, which calculates some important structural and transport properties, including the geometrical connectivity of an individual phase, the specific surface area, etc. Particularly, a self-developed D3Q15 LB (lattice Boltzmann) model is utilized to calculate the effective thermal (or electric) conductivity and the effective species diffusivity in electrolyte (or solid) phase, and the tortuosity of an individual phase. The LB model predictions indicate that the effective transport coefficients are closely related to the micro-morphology in electrodes and the tortuosity values assessed by LBM are more reliable than those predicted by random walk simulation or the Bruggeman equation.
Effect of multiple temperature-step annealing on the performances of polymer solar cells
Authors: Sun Kai  , He Zhi-Qun  , Liang Chun-Jun  ,   Key Laboratory of Luminescence and Optical Information, Ministry of Education, Institute of Optoelectronic Technology, Beijing Jiaotong University, Beijing 100044, China
Published: December 2020

In the paper, a series of bulk-heterojunction polymer solar cells using poly(3-hexyl-thiophene) (P3HT) as a donor and indene-C60 bisadduct (ICBA) as an accepter is fabricated. Effect of annealing process on the cell characteristics is investigated. It is found that the cell having a multiple temperature-step annealing can distinctly improve its photovoltaic performance. At the same time the multiple temperature-step annealing process can also significantly improve the life time of the device. The device maintains a stable performance without being encapsulated.
Correlation of the holding behaviour of the holding-based network of Chinese fund management companies based on the node topological characteristics
Authors: Li Hua-Jiao  , An Hai-Zhong  , Huang Jia-Chen  , Gao Xiang-Yun  , Shi Yan-Li  ,   School of Humanities and Economic Management, China University of Geosciences, Beijing 100083, China;,   Key Laboratory of Carrying Capacity Assessment for Resource and Environment, Ministry of Land and Resource, Beijing 100083, China;,   Laboratory of Resources and Environmental Management, China University of Geosciences, Beijing 100083, China;,   School of Energy Resources, China University of Geosciences, Beijing 100083, China;,   School of Economics and Management, Beijing Jiaotong University, Beijing 100044, China
Published: December 2020

The data in this paper was collected from the semi-annual reports between 2003 and 2012 which disclosed the Chinese fund management companies' shareholdings in different listed companies. The holdings-based network of Chinese fund management companies is constructed by taking fund management companies as the nodes, the holding of stock of the same listed company at the same period as the edges, and the number of the listed companies holding at the same time as the weight of the edges. Based on the methods such as statistical physics, etc., the stability of the networks at different times is analyzed, and then the correlation of the holding behavior between the nodes with different topological characteristics and three different sets of nodes are calculated and analyzed. Three different sets are the set of nodes in the full graph with a given stock at t-1 (the first type of nodes), the set of nodes in the holing-based network without holding a given stock at t-1 (the second type of nodes), and the set of the new nodes which appear at t (the third type of nodes). The result shows as follows. Firstly, the correlation coefficient of the holding behavior between the node and the second type of nodes rises with the node clustering coefficient increasing; secondly, the node holding behavior is highly correlated with the second type of nodes and with the third type of nodes only when the values of the node average degree and strength are high; finally, the node holding behavior is not related to the third type of nodes at all. This paper propose a new method to study the correlation of stock market, and it is a basis for the further investigation on the structure equivalence network in stock market and also the differences of the importance between the nodes.
Particles discrete element method based on manifold cover for macro-mesoscopic fracture of rock mass
Authors: Li Shu-Chen  , Ping Yang  , Li Shu-Cai  , Kou Qiang  , Ma Teng-Fei  , Feng Bing-Yang  ,   Geotechnical and Structural Engineering Research Center, Shandong University, Jinan 250061, China
Published: December 2020

The rock mass can be assumed to be homogeneous material from the macroscopic view, but it is a heterogeneous material at a mesoscopic scale and its physico-mechanical properties are discontinuous in space. Therefore, it is necessary to research the generation and development of pre-peak micro cracks in rocks and frictional characteristics between post-peak mineral particles from macro-meso and multi-scale perspectives to know the substantive characteristics of rock failure and instability. This paper, based on the manifold cover concept, proposes a new discrete element numerical method (i.e. Manifold Particle Discrete) combining with the particle contact model, so as to introduce the concept of stress boundary. This method can be applied to the entire process of analyzing rock failure. By analyzing the manifold cover and ball particle model, this paper constitutes the ball unit cover function of three-dimensional manifold cover, establishes tetrahedron units, obtains the equilibrium equation and compatible equation of the MPD model. It also verifies the accuracy of the proposed numerical method and the feasibility of rock failure analysis through numerical examples.
Analysis and calculation of a 170 GHz megawatt-level coaxial gyrotron
Authors: Qin Mi-Mi  , Luo Yong  , Yang Kuo  , Huang Yong  ,   School of Physical Electronics, University of Electronics Science and Technology of China, Chengdu 610054, China;,   Department of Electrical Engineering, A'ba Teachers College, Wenchuan 623001, China
Published: December 2020

Gyrotrons are the most promising microwave source devices that can be used in the International Thermonuclear Experimental Reactor, but there are many difficulties to be solved in study and design of gyrotrons to meet the requirements. In this paper, the beam-wave interactions of a 170 GHz megawatt-level smooth-wall coaxial gyrotron are studied numerically. In order to attain high efficiency and stable radiation, TE31,12 mode that lies in a relative sparse spectrum is selected as the operating mode, and the beam-wave coupling coefficient and start oscillation current are calculated by a set of source codes developed by Matlab. Taking into account the electronic velocity spread and cavity wall resistivity, and based on a single-mode approximation, the optimization design and simulation of beam-wave interaction of a 170 GHz megawatt smooth-wall coaxial gyrotron have been fulfilled. The relationships between efficiency and magnetic field, and the voltage, current, taper angle of insert, and other parameters are presented. Results show that the voltage and magnetic field have great influence on efficiency; however, the current and velocity spread do change slightly, thus reduce the requirements of electron gun design. In addition, the optimized taper angle of insert and coaxial cavity geometry parameters can improve the efficiency, reduce the impact of velocity spread on efficiency, and can achieve an electronic efficiency around 50% and an output power 1.7 MW.
Reduction of the angular dispersion in self-diffraction signals by using a prism
Authors: Zhang Su-Xia  , Li Fang-Jia  , Liu Jun  ,   State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China;,   MOE Key Laboratory of Advanced Micro-structured Materials, Institute of Precision Optical Engineering, School of Physics Science and Engineering, Tongji University, Shanghai 200092, China
Published: December 2020

Self-diffraction effect has very important applications in the field of femtosecond laser, such as to improve the temporal contrast of femtosecond pulses, to be used as the reference pulse of self-reference spectral interferometry, and as the signal of self-diffraction frequency-resolved optical gating, etc. However, in the self-diffraction signal of femtosecond pulses with a broadband spectrum angular dispersion exists obviously, which will limit the application of self-diffraction effect. In this paper, the self-diffraction signal angular dispersion of femtosecond pulses is obviously reduced, when a right-angle prism is located in the light path of an incident beam with an incident angle of 23° to the prism. The experimental result provides a useful reference for the application of the self-diffraction effect to the research of femtosecond laser pulse in the future.
High power red to mid-infrared laser source from intracavity sum frequency optical parametric oscillator pumped by femtosecond fiber laser
Authors: Zhang Li-Meng  , Hu Ming-Lie  , Gu Cheng-Lin  , Fan Jin-Tao  , Wang Qing-Yue  ,   Ultrafast Laser Laboratory, College of Precision Instrument and Optoelectronics Engineering, Key Laboratory of Optelectronic Information Technology (Ministry of Education), Tianjin University, Tianjin 300072, China
Published: December 2020

A femtosecond laser source tuned from red to mid-infrared is demonstrated. It is based on intracavity sum frequency generation of a MgO-doped periodically poled LiNbO3 optical parametric oscillator synchronously pumped by mode-locked Yb large-mode-area photonic crystal fiber, which has high average power and high repetition rate. The optical parametric oscillator has a wide spectral tuning range from 1450–2200 nm (for the signal) and 2250–4000 nm (for the idler) while the wavelength of the pump is 1040 nm. In the experiment, the output power of 374 mW at 1502 nm is achieved when the pump power is 2 W and the slope efficiency is 18.7%. In addition, 166 mW idler at 3.4 μm are achieved. By using a β-BaB2O4 for intracavity sum frequency generation, the femtosecond pulse over 610–668 nm is obtained. A 694 mW average output power of sum frequency generation is achieved for 4.1 W pump, representing 16.9% conversion efficiency at 615 nm.
Design of multistatic sonar space-time code detection signal and time reversal copy-correlation detection technology
Authors: Sheng Xue-Li  , Lu Jia  , Ling Qing  , Xu Jiang  , Dong Wei-Jia  ,   Science and Technology on Underwater Acoustic Laboratory, Harbin Engineering University, Harbin 150001, China;,   College of Underwater Acoustic Engineering, Harbin Engineering University, Harbin 150001, China;,   Science and Technology on Complex Ship Systems Simulation Laboratory, Beijing 100161, China
Published: December 2020

A space-time code (STC) detection signal is designed for multistatic sonar to distinguish the multiple access echoes in the shallow water, and a time reversal (TR) copy-correlation detection method is presented for solving the problem of multi-path sub-channel differences when the vertical array is oblique. STC detection signal has a good orthogonality through modulating with pseudo-random signals, can distinguish multiple access target echoes while combating with sub-channel attenuation. The vertical array affected by current is oblique, its multi-path sub-channel differences causing signals from different sub-channels can not focus on the receiving end, so the array gain decreases. Meanwhile, it causes resolution to decline and the error rate of signal judgment to rise. Channel training signal is designed to estimate the sub-channel multipath environment, and the best matched detection signal for sub-channel differences is got through virtual time reversal mirror (VTRM) with the estimated channels and the received signal being detected by TR copy-correlation. Simulation results of tristatic sonar (two transmitters and one receiver) show that the SPC detection signal and TR copy-correlation can meet the requirements of multistatic sonar detection and distinguish the multiple access echoes in low SIR and complex channel environment. The best matched detection signal is got through VTRM (virtual time reversal mirror) with the estimated channels, and the received signal is detected by TR copy-correlation. Simulation results of tristatic sonar (two transmitters and one receiver) show that the STC detection signal and TR copy-correlation can meet the requirements of multistatic sonar detection and distinguish the multiple access echoes in low SIR environment.
Passive source localization using RROA based on eigenvalue decomposition algorithm in WSNs
Authors: Hao Ben-Jian  , Li Zan  , Wan Peng-Wu  , Si Jiang-Bo  ,   State Key Laboratory of Integrated Services Networks, Xidian University, Xi'an 710071, China;,   School of Telecommunications Engineering, Xidian University, Xi'an 710071, China
Published: December 2020

When in WSNs sensors receive different noise intensities or the wireless transmission channel has the shadow fading effect, the association metrics estimation method for range ratios of arrival (RROA) and the passive source localization algorithm based on RROA are studied. Firstly, the eigenvector decomposition (EVD) approach is used to estimate the RROA association metrics. The noise intensity received by each sensor can be estimated by performing EVD on the covariance matrix of the received signal. Secondly, by rotating the array reference point at each of the array sensors, a number of covariance matrices are constructed and the EVD approach can be used to cancel the shadow fading effect. Thus RROA association metrics can be estimated reliably. Finally, the weighted-least-squares (WLS) algorithm based on the RROA association metrics is proposed. The proposed approach is robust to channel shadow fading effect and different noise intensities received.
Theoretical and experimental investigations on aero-optical effect at the second stage of the compressible mixing layer
Authors: Gan Cai-Jun  , Li Lang  , Ma Han-Dong  , Xiong Hong-Liang  ,   China Academy of Aerospace Aerodynamics, Beijing 100074, China
Published: December 2020

Using dimensional analysis and experimental technique, the aero-optical effect at the second stage of a compressible mixing layer has been investigated. The theoretical analysis focuses on the relation between two-dimensional large-scale structure of a mixing layer and its corresponding aero-optical effects. Results show that the time-averaged bore-sight error (BSE) has nonlinear variability with the convective Mach number (Mc). Moreover, we also present the relation among time-averaged BSE and turbulent kinetic energy, Reynolds shear stress at the interface between the mixing layer and free stream. Experimental results from a thin beam light passing through the compressible mixing layer verifly the theoretical result between time-averaged BSE and Mc.
Dynamic characteristics of laser-induced bubble moving in venturi
Authors: Li Xiao-Lei  , Qin Chang-Jian  , Zhang Hui-Chen  ,   Transportation equipments and Ocean Engineering College, Dalian Maritime University, Dalian, Liaoning, 116026, China
Published: December 2020

Laser-induced bubble was generated by YAG laser bombarding the metal target in the water at different venturi inlet pressures. The movement of laser-induced bubble in venturi was recorded by a high-speed video system. Characteristics of flow field in venturi and bubble collapse were analyzed by computational fluid dynamics. Results show that the process of laser-bubble moving in venturi can be classified into four periods: generation, extrusion, initial collapse, and collapse period. Bubble collapse depends on the state of flow field. Bubble does not collapse when the flow is in laminar state. However, bubble collapses when the flow is in turbulent state. The collapse phenomenon becomes prominent with increasing turbulence intensity. The bubble collapse at a fixed point can be realized in the laser-bubble generation and movement system.
Drag reduction on micro-structured hydrophobic surfaces due to surface tension effect
Authors: Song Bao-Wei  , Ren Feng  , Hu Hai-Bao  , Guo Yun-He  ,   School of Marine Science and Technology, Northwestern Polytechnical University, Xi'an 710072, China
Published: December 2020

This article studies drag reduction rule and gas restoration and retention of hydrophobic surfaces numerically when taking into consideration the surface tension effect, the microstructure here is chessboard-like and the Reynolds number varies from 3,000 to 30,000. Results show that gas restoration and retention keep well, and a maximum drag reduction rate of approximately 30% has been gained at small Reynolds number(Re<15000). When Re is too large, water will swarm into microstructures, and keeping a good gas-liquid interface becomes difficult. Meanwhile, drag reduction rate remains variable and hydrophobic surfaces do not reduce drag. Through mechanical analysis we find that the influence of shear stress is weakened due to surface tension effect, thus the gas in microstructures can be effectively stored at low flow speed and drag is reduced.
Influence of defects on friction and motion of carbon nanotube
Authors: Li Rui  , Sun Dai-Hai  ,   School of Mechanical Engineering, University of Science & Technology Beijing, 100083, China
Published: December 2020

Motion and friction of carbon nanotubes with vacancy defects or Stone-Thower-Wales (STW) defects on them are investigated in commensurate states and incommensurate states by molecular dynamics simulation. Results show that defects lead to incommensurate state in part of interfaces, thus decreasing the friction. More amount of STW defects would cause larger distortion of carbon nanotube, smaller lateral force amplitude, more local incommensurate state of interfaces and smaller friction. The friction of carbon nanotube with vacancy defects is obviously larger than carbon nanotube with STW defects. The reason is that the carbon nanotube with vacancy defects will change its motion in later period of motion, which can increase energy dissipation. Defects barely have influence on the friction of carbon nanotubes in incommensurate state because interfaces are all in incommensurate state whether they are having defects or not.
Research on dark signal degradation in 60Co γ-ray-irradiated CMOS active pixel sensor
Authors: Wang Bo  , Li Yu-Dong  , Guo Qi  , Liu Chang-Ju  , Wen Lin  , Ma Li-Ya  , Sun Jing  , Wang Hai-Jiao  , Cong Zhong-Chao  , Ma Wu-Ying  ,   Xinjiang Technical Institute of Physics and Chemistry, CAS., Urumqi 830011, China;,   Key Laboratory of Functional Materials and Devices under Special Environments, CAS., Urumqi 830011, China;,   Xinjiang Key Laboratory of Electric Information Materials and Devices, Urumqi 830011, China;,   Graduate University of Chinese Academy of Sciences, Beijing 100049, China;,   Chongqing Optoelectronics Research Institute, Chongqing 400060, China
Published: December 2020

A study of ionizing radiation effects is presented for CMOS active pixel sensors manufactured in a 0.5-μm CMOS (complementary metal oxide semiconductor)by n-well technology. The basic mechanisms that may cause failure are also presented. After exposure in γ-rays, the most sensitive parts to radiation-dark signals and dark signal non-uniformity are discussed, i.e. the physical mechanism of the degradation by irradiation. One can see from the experiment that the mean dark signals are dramatically increased with total dose for both operated and static devices. Static device seems more affected by irradiation than operated device. We find that most part of the total dark signal in a pixel comes from the depletion of the photodiode edge at the surface and the rest part is caused by the leakage of the source region of the reset transistor. Dark signal non-uniformity follows the dark current evolution with total dose. Further study of photodiode and LOCOS (local oxidation of silicon) isolation behaviors under irradiation should be done so as to correctly use this qualification techniques on MOS sensors manufactured in CMOS n-well technology process.
Improved properties of boron-doped zinc oxide films with In2O3：Sn interlayers for solar cells
Authors: Zhao Hui-Xu  , Chen Xin-Liang  , Yang Xu  , Du Jian  , Bai Li-Sha  , Chen Ze  , Zhao Ying  , Zhang Xiao-Dan  ,   Institute of Photo-electronic Thin Film Devices and Technology, Tianjin Key laboratory of Photo-electronic Thin Film Devices and Technology, Key laboratory of Opto-electronic Information Science and Technology for Ministry of Education, Nankai University, Tianjin 300071, China
Published: December 2020

Boron-doped zinc oxide (BZO) films with a natural pyramid-textured surface grown by metal organic chemical vapor deposition (MOCVD) have large light trapping effect in thin film silicon solar cells when used as front contact electrodes. However, the surface topography of traditional BZO films is so sharp as to damage the quality of the subsequent silicon thin film materials and to reduce the photovoltaic conversion efficiency of the solar cells. In this work, an ultra-thin In2O3:Sn(ITO)film (～ 4 nm) is used as the interlayer in the sandwiched structure of the multilayer films, i.e. glass/bottom BZO layer /ITO interlayer/top BZO layer. The surface properties can be improved through modulating the thickness of the top BZO layer. Appropriate thickness of top BZO layer and ITO interlayer are helpful for obtaining the cauliflower-like surface morphology and thus the sharp structure becomes relatively gentle, but the surface morphology still keeps a pyramid feature when depositing thicker top BZO layer. The relatively gentle surface morphology could promote crystallization quality ofc-Si:H thin film materials and reduce cracks in intrinsic layer and TCO/P-Si interface defects. Finally, this new sandwiched structure of multilayer ZnO films is applied in c-Si:H p-i-n thin film solar cells. Compared with traditional BZO films, the quantum efficiency (QE) of solar cells with a sandwiched structure of ZnO increases by about 10%, and both the open-circuit voltage (Voc) and short-circuit current density (Jsc) may increase and thus improve the solar cell efficiency.
Theoretical study of the effect of W-doping on the conductivity of β-Ga2O3
Authors: Zheng Shu-Wen  , Fan Guang-Han  , He Miao  , Zhao Ling-Zhi  ,   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 conductivity of W-doped β-Ga2O3 is investigated by using the ultra-soft pseudopotential (USP) approach of the plane-wave based upon density functional theory. The optimized structural parameters, total electron density of states, and energy band structures of β-Ga2(1-x)W2xO3 (x=0, 0.0625, 0.125) are calculated. It is found that the volumes are slightly increased and the total energies are going up in the Ga2(1-x)W2xO3 system with increasing W-doping concentration, which causes the system instability. When the W concentration is smaller, the calculated conductivity and electronic mobility are higher, but when the W concentration is increased, the average electron effective mass becomes bigger and the energy gap becomes narrower. The results are consistent with experimental data.
Photoluminescence of monocrystalline silicon irradiated by femtosecond pulsed laser
Authors: Zhu Min  , Li Xiao-Hong  , Li Guo-Qiang  , Chang Li-Yang  , Xie Chang-Xin  , Qiu Rong  , Li Jia-Wen  , Huang Wen-Hao  ,   School of Science, Southwest University of Science and Technology, Laboratory of Matter Characteristic Research under Extreme Conditions, Mianyang 621010, China;,   Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei 230026, China
Published: December 2020

We report the photoluminescence of monocrystalline silicon irradiated by femtosecond pulsed laser in different environments (deionized water and air) and energy density conditions. The field emission scanning electron microscope (FESEM) measurement results show the formation of completely different morphologies on silicon surface in different environments. A stripe-like microstructure on the silicon surface in air is formed in contrast to the smaller and coral-like microstructure generated in the deionized water. By using the energy dispersive spectroscopy (EDS) we find that silicon and oxygen is the main elemental composition on femtosecond laser-induced silicon surface, and the content of oxygen on the sample surface formed in the deionized water is nearly four times larger than that in air. The Si-Si bond (610 cm-1) and Si-O-Si bond vibrations (1105 cm-1) are detected mainly in the Fourier transform infrared transmission spectrum (FT-IR). The photoluminescence (PL) spectroscopy measurement results show that visible blue luminescence is observed both from the silicon ablated in the deionized water and in air, while the shape and position of the emitted luminescence peak are substantially the same. However, the luminescence intensity of silicon etched in the deionized water is close to 3 times stronger than that in air when the photoluminescence is excited at respective most suitable excitation wavelength. A more interesting phenomenon is that the position and shape of the photoluminescence peak in the visible range are basically not changed. The studies confirm that oxygen plays an important role in photoluminescence enhancement. Photoluminescence may be mainly generated by the formation of oxygen defects SiOx and the content of low oxide SiOx (x<2) determines the luminous intensity level.
Reduction of metal artifacts caused by multiple metallic objects in computed tomography
Authors: Wei Xing  , Yan Bin  , Zhang Feng  , Li Yong-Li  , Xi Xiao-Qi  , Li Lei  ,   Institute of Information System Engineering, Information Engineering University, Zhengzhou 450002, China;,   He Nan Province People's Hospital, Zhengzhou 450002, China
Published: December 2020

High-attenuation objects like metals will result in metal artifacts in computed tomography images. Compared with single metallic object, artifacts due to multiple and large-scaled metallic objects is more complicated in representation and have much worse effects on reconstructed image. State-of-the-art metal artifacts reduction for multiple metal objects based on interpolation method cannot solve the beam hardening inside the metals, and can easily make mistakes in segmentation and interpolation. Aiming at reduction of multiple metallic objects, this paper simulates the production of the artifacts and proposes a metal artifacts reduction method based on projections correction. In this method, metal regions are firstly segmented directly from projection domain, and then a correction model is established for projections in metal regions. Finally, correction is made by adjusting parameters of the model. The optimal solution of the parameters is achieved by NM-simplex method that makes the gray entropy of the reconstructed image minimum. The simulation results and obtained data show that the present method significantly improves metal artifact due to multiple metallic objects and provides a better image quality than that obtained using interpolation.
Quantum dialogue protocols with identification over collection noisy channel without information leakage
Authors: Wu Gui-Tong  , Zhou Nan-Run  , Gong Li-Hua  , Liu San-Qiu  ,   Department of Physics, Nanchang University, Nanchang 330031, China;,   Department of Electronic Information Engineering, Nanchang University, Nanchang 330031, China
Published: December 2020

Three quantum dialogue protocols with identification are proposed under the condition of collection noise. They are used to resist collective-dephasing noise, collective-rotation noise and both collective noises respectively. The two communication parties encode their own secret information into the quantum states with the generalized unitary transformation. Each communication party can deduce the secret message of his counterpart according to his secret message and the two quantum states (one is quantum state before being encoded, and the other is quantum state after being encoded), to achieve a quantum dialogue. It is important that our protocols all should be able to resist various attacks, such as disturbance attack, Trojan horse attack, intercept-resend attack and entanglement measure attack. Moreover, the efficiency and the information leakage of the proposed protocol are analyzed in detail.
Nonlinear Rossby waves excited slowly changing underlying surface and dissipation
Authors: Song Jian  , Yang Lian-Gui  , Liu Quan-Sheng  ,   School of Mathematical Science, Inner Mongolia University, Hohhot 010021, China;,   College of Sciences, Inner Mongolia University of Technology, Hohhot 010051, China
Published: December 2020

An inhomogeneous Benjamin-Davis-Ono-Burgers (BDO-Burgers) equation including underlying surface, slowly changing underlying surface and turbulent dissipation is derived in terms of quasi-geostrophic vorticity equation by employing the singular perturbation method. An inhomogeneous BDO-Burgers equation describing the evolution of the amplitude of solitary Rossby waves is investigated.
A new network structure entropy based on maximum flow
Authors: Cai Meng  , Du Hai-Feng  , Marcus W Feldman  ,   School of Management, Xi’an Jiaotong University, Xi’an 710049, China;,   Center for Administration and Complexity Science, Xi’an Jiaotong University, Xi’an 710049, China;,   Morrison Institute for Population and Resource Studies, Stanford University, Stanford 94305, USA
Published: December 2020

Entropy is an index to reflect the heterogeneity of network structure. By introducing the concept of network flow which comprehensively considers radial measurement and betweenness measurement, we define a new network structure entropy index to solve the problem that classical entropy indices cannot effectively reflect heterogeneity of the global network. Analysis results concerning specific network (e.g. public data set Dolphins network) indicate that this new entropy index can reflect the real topological structure of network, and effectively overcome the shortcomings of other network entropy indices to some extent. The theoretical analyses and simulation experiments on Erdös-Renyi random network, nearest-neighbor coupled network, star network, Barabási-Albert scale-free network, Benchmark network, and the Watts-Strogatz small-world network further prove the effectiveness and applicability of this new network structure entropy index to describe the characteristics of ordinary complex network structures.
Collision energy effect on stereodynamics for Sr+CH3I→SrI+CH3
Authors: Ma Jian-Jun  ,   Department of Applied Physics, Anhui University of Technology, Maanshan 243002, China
Published: December 2020

Based on semiemperical London-Eyring-Polanyi-Sato (LEPS) potential energy surface (PES), stereodynamic properties of the reaction Sr+CH3I→SrI+CH3 in different initial reagent collision energies are studied theoretically by using the quasiclassical trajectory method. The results indicate that the collision energy of reagent has considerable influences on the orientations and alignments of angular momentum of products for the title reaction.
Quantum wave-packet and quasiclassical trajectory of reaction S(3P)+HD
Authors: Duan Zhi-Xin  , Qiu Ming-Hui  , Yao Cui-Xia  ,   State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China;,   School of Physics and Mathematics, Dalian Jiaotong University, Dalian 116028, China
Published: December 2020

In this paper, the S(3P)+HD→SD+H and SH+D reactions are studied by means of quantum wave packet (QMWP) and quasi-classical trajectory (QCT) methods on a new ab initio 3A" potential energy surface. The reactive probabilities, integral cross sections, intra-molecular isotope parameters and product rotational alignment parameters for both reactive channels are calculated for collision energies in a range between 0.8 and 2.2 eV. The results reveal a pronounced isotopic effect. Plots of the potential energy surface and typical reactive trajectories show the evidence of an additional reaction mechanism for the SD+H product channel. This reaction mechanism, together with mass combination, can explain the isotopic effect for the title reaction.
High power microwave propagation properties in radio frequency breakdown plasma
Authors: Song Wei  , Shao Hao  , Zhang Zhi-Qiang  , Huang Hui-Jun  , Li Jia-Wei  , Wang Kang-Yi  , Jing Hong  , Liu Ying-Jun  , Cui Xin-Hong  ,   Science and Technology on High Power Microwave Laboratory, Northwest Institute of Nuclear Technology, Shaanxi 710024, China
Published: December 2020

The effect of plasma on the microwave propagation properties is investigated experimentally by using a high power microwave combiner. The plasma is generated by radio-frequency breakdown on the coupling slit of the combiner through changing the power or pulse width of the prime microwave source. The plasma diffuses from the slit to the high power microwave transmission channel, and induces the absorption of microwave energy and the rotation of microwave polarization. The results show that the spread velocity of plasma is about 1 μs/cm, and the duration is about 5 μs. The polarization rotating angle is determined by electron density and microwave frequency. The maximum rotating angle is 4.1° while the number of electron is about 3.7×1015.
A method of detecting line spectrum of ship-radiated noise using a new intermittent chaotic oscillator
Authors: Cong Chao  , Li Xiu-Kun  , Song Yang  ,   Acoustic Science and Technology Laboratory, Harbin Engineering University, Harbin 150001, China;,   College of Underwater Acoustic Engineering, Harbin Engineering University, Harbin 150001, China
Published: December 2020

In order to achieve the effective detection of the line spectrum of ship-radiated noise in low signal-to-noise ratio (SNR), in this paper we improve the conventional intermittent chaotic oscillator series method, and propose a signal detection method based on the adaptive step intermittent chaotic oscillator. Through setting a sequence of the calculating steps which can cover the frequency band of the signal to be measured, the method can use just one Duffing oscillator to accomplish the searching detection for the weak signal with unknown frequency. In order to further improve the weak signal detection performance, we analyze the Holmes Duffing equation’s sensitivity for weak signal detection at different internal frequencies. Through theoretical analysis and simulation study, it is found that the Duffing oscillator has the best weak signal detection performance when its internal frequency is 0.4 rad/s. According to this result we optimize the Duffing oscillator. The simulation result shows that the signal detection performance of the improved Duffing oscillator increases 14 dB. In the end, we use the proposed method to detect a set of actual data which contain the ship radiated line spectrum, the result shows that this method could achieve effective detection of the line spectrum in low SNR.
Local atomic short-range-order features of NiZr, AlZr and BCr crystalline phases
Authors: Chen Ji-Xiang  , Zhou Shuo-Yao  ,   Department of Physics, Dalian Maritime University, Dalian 116026, China
Published: December 2020

Crystalline and non-crystalline alloys are characterized by specific nearest-neighbor coordination polyhedral clusters representing the local tomic short-range-order features of their parent phases. In this paper, NiZr, AlZr and BCr crystalline phases are investigated from the view of clusters because they have the same structures described by traditional crystallography. The result is that they have the different local atomic features, which are likely to be due to the slight differences in the size of unit cell and atomic position. Different from traditional crystallography, this description gives the structure information about short-range-order of that phase, so it can provide a new idea for phase classification and material design.
Numerical investigation of non-ionizing energy loss of proton at an energy range of 300 eV to 1 GeV in silicon
Authors: Zhu Jin-Hui  , Wei Yuan  , Xie Hong-Gang  , Niu Sheng-Li  , Huang Liu-Xing  ,   Northwest Institute of Nuclear Technology, Xi’an 710024, China;,   State Key Laboratory of Intense Pulsed Radiation Simulation and Effect, Xi’an 710024, China
Published: December 2020

The displacement damage due to non-ionizing energy loss (NIEL) is the main reason of photo-electronic device failure in space radiation environment. The basic mechanisms of NIEL are Coulomb and nuclear interactions of silicon atoms with incident protons at energies ranging from threshold to 1 GeV. In the low energy region where the Coulomb interaction is dominant, the NIEL can be calculated by analytical method and TRIM code. MCNPX/HTAPE3X is used to calculate NIEL when the nuclear elastic and non-elastic interactions between proton and target atoms are significant in the high energy range. The results show that it is reasonable to use MCNPX/HTAPE3X to evaluate the NIEL by recoiling nucleus caused by high energy protons. The combination of analytical method and TRIM code can calculate NIEL induced by Coulomb interaction in low energy range, which gives the NIEL of proton in silicon in an energy range from 300 eV to 1 GeV.
Simulation and calculation of the absorbing microwave properties of carbon nanotube composite coating
Authors: Chen Ming-Dong  , Jie Xiao-Hua  , Zhang Hai-Yan  ,   School of Material and Energy, Guangdong University of Technology, Guangzhou 510006, China;,   Physics Teaching and Experiment Center of Campus of High Education Mega Center, South China University of Technology, Guangzhou 510006, China
Published: December 2020

How to optimize the absorbing microwave properties by using the parameters of carbon nanotube composite coating is a hotspot in the study of electromagnetic shielding. However, the study on the influence of coating parameters on absorbing microwave properties mainly stays in the stage of experimental study, and the influence of structure parameters of carbon nanotube on absorbing microwave properties has not been reported yet. Therefore, it is significant to study the method of optimizing the absorbing microwave properties of materials through micro-structure of the carbon nanotube composite coating. Based on an equivalent circuit of multi-wall carbon nanotubes, using the relationship between the parameters of each element in the equivalent circuit to study the mechanism of carbon nanotube loss microwave, an expression of absorbing microwave properties about carbon nanotube structure parameters is derived. According to the expression, the microwave reflection ratio of coating is calculated and simulated by Matlab software, which is affected by the length, diameter and coating thickness of carbon nanotube and the number of carbon nanotubes. The simulation result shows that the variation of reflection ratio curve of coating with the number of carbon nanotubes is consistent with the experimental results. The number of carbon nanotubes and the thickness of coating are the vital parameters, which influence the absorption intensity and absorption position, while the diameter and length of carbon nanotube are the vital parameters, which influence the absorption intensity.
Digital shearography investigation on the out-plane deformation of the Portevin-Le Chatelier bands
Authors: Gao Yue  , Fu Shi-Hua  , Cai Yu-Long  , Cheng Teng  , Zhang Qing-Chuan  ,   CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Modern Mechanics, University of Science and Technology of China, Hefei 230027, China
Published: December 2020

Digital shearography is proposed to study the out-plane deformation of the Portevin-Le Chatelier (PLC) band during tensile tests in an Al alloy. The geometrical shape and propagation of the PLC bands are visualized in real time through fringe pattern in subtracted images. In 1/15 s, the maximum out-plane displacement is 245 nm within the PLC band. The displacement distribution is asymmetric while in fringe pattern, the white fringe is narrower in the front of the PLC band than in the rear. In addition, the evolution processes of position shifting and inclination transition of the PLC bands are presented in detail.
Electrochemical potential equilibrium criterion of Invar alloy
Authors: Han Guang  , Sun Cheng  , Wu Di  , Chen Wei-Rong  ,   College of Physics, Dalian University, Dalian 116622, China
Published: December 2020

In this paper, Invar alloy composition is described by using binary cluster as basic structural unit. We use “cluster resonance” structure model and establish the connection of a known binary clusters with atoms by an atomic ratio of 1:x to describe Invar alloy component empirical criterion. Invar alloy composition formula is given, that is, Invar alloy component=[clusters]1 (glue atom)x. Using this criterion, some of Invar alloy compositions are calculated, and it is confirmed that the experimentally determined typical Invar alloy compositions are in good agreement with the compositions calculated from the formula. This shows that the formation of the rule of the Invar alloy composition is well explained by the composition formulae criterion.
Effects of annealing in H2 atomsphere on optoelectronical properties of Nb-doped TiO2 thin films
Authors: Zhang Bin  , Wang Wei-Li  , Niu Qiao-Li  , Zou Xian-Shao  , Dong Jun  , Zhang Yong  ,   Institute of Optoelectronic Materials and Technology, South China Normal University, Guangzhou 510631, China
Published: December 2020

Niobium-doped TiO2 thin films are deposited on strontium titanate substrates by E-beam evaporation deposition. Effects of post-annealing in hydrogen atmosphere on their optoelectrical properties are studied. The results show that the annealing in hydrogen atmosphere can enhance their conductivity values efficiently. The corresponding optium resistivity reaches 5.46×10-3 Ω·cm, and the transmittance values of the thin films are 60%–80%. The improvement in the conductive performance is attributed to the increase of the grain size of polycrystalline thin film, the formation of a lot of oxygen vacancies and H-doping caused by annealing in hydrogen atmosphere.
Experimental investigation and numerical simulation of defect elimination by CO2 laser raster scanning on fused silica
Authors: Jiang Yong  , He Shao-Bo  , Yuan Xiao-Dong  , Wang Hai-Jun  , Liao Wei  , Lü Hai-Bing  , Liu Chun-Ming  , Xiang Xia  , Qiu Rong  , Yang Yong-Jia  , Zheng Wan-Guo  , Zu Xiao-Tao  ,   Joint Laboratory for Extreme Conditions Matter Properties, Southwest University of Science and Technology and Research Center of Laser Fusion, Mianyang 621010, China;,   Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900, China;,   School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu 610054, China
Published: December 2020

Based on the fact that fused silica material can strongly absorb 10.6 μm CO2 laser, a method of using CO2 laser multi-time raster scanning to repair the densely distributed scratches and polishing pits is investigated. The experimental results indicate that the scratches and polishing pits can be fully eliminated under the appropriate parameters. The damage threshold testing results also indicate that the damage threshold for fully eliminating scratches and polishing pits can reach or exceed the damage threshold of substrate. Meanwhile, Combining the simulation results obtained by finite element software-Ansys, the processes of the scratches and polishing pits eliminated by CO2 laser are analyzed. The present work is of significance for the study on how to eliminate the scratches and polishing pits on the surface of component.
Electronic transport properties of oligophenyleneethynylene molecular junctions in alkaline and acid solutions
Authors: Lin Xiao-Na  , Zhang Guang-Ping  , Ren Jun-Feng  , Yuan Xiao-Bo  , Hu Gui-Chao  ,   College of Physics and Electronics, Shandong Normal University, Jinan 250014, China
Published: December 2020

Using nonequilibrium Green’s function method combined with density functional theory, we theoretically investigate the influences of alkaline and acid solutions on electronic transport properties in oligophenyleneethynylene molecular junctions with amino and carboxylic groups. The numerical results show that comparing with the case of neutral state, the conductance of the molecular junction is double improved and the rectifying direction is inverted when carboxylic group is deprotonated in the alkaline environment. On the other hand, the rectification ratio is enhanced trebly and the rectifying direction is inverted similarly when amino group is protonated in the acid environment. This theoretical work presents a chemically controllable method of manipulating conductance and rectification of molecular junctions.
Spontaneous oscillation analysis of neural mass model using describing function approach
Authors: Wang Jun-Song  , Xu Yao  ,   School of Biomedical Engineering, Tianjin Medical University, Tianjin 300070, China;,   Department of Neuroscience, Johns Hopkins University, Baltimore 21218, USA
Published: December 2020

Neural mass model (NMM) can generate spontaneous oscillation even in a resting state. However, it remains little known which mechanism is responsible for NMM’s spontaneous oscillation. From dynamical theory, spontaneous oscillation is an intrinsic property of nonlinear system, which means that the sigmoid nonlinear function (S function) of NMM plays a key role in the emergence of its spontaneous oscillation. In this study, describing function approach is employed to analyze the spontaneous oscillation characteristics of a kind of extended NMM. Firstly, the describing function of S function is derived, through which the two S functions in excitatory and inhibitory feedback loop, respectively, are approximated. Secondly, the NMM is transformed into a typical block diagram composed of a nonlinear unit and a linear unit. Thirdly, in the theoretical framework of describing function approach, theoretical analysis of the spontaneous oscillation characteristics of NMM is conducted, and the oscillation frequencies are determined. The simulation results demonstrate that the theoretical results are correct and the employed approach is effective. Since S function exists extensively in neural system, the proposed approach has a potential application in the spontaneous oscillation analysis of other neural model.