bluuebunny/crossref_metadata_2025 huggingface dataset:
Three infinite sequences for evolution of partially reflected short-crested waves by a vertical wall breakwater
Authors: Huang Hu  ,   Shanghai Institute of Applied Mathematics and Mechanics, Shanghai University, Shanghai 200072, China
Published: December 2020

Three infinite sequences of analytical solution numbers for partially reflected n-chromatic n-directional short-crested waves by a vertical wall breakwater are found, which are significant for water wave theory and engineering application.
Laser driven shock accelerated ion energy spectrumbroadening mechanisms in over-dense plasmas
Authors: Ling Wei-Jun  , Dong Quan-Li  , Zhang Lei  , Zhang Shao-Gang  , Dong Zhong  , Wei Kai-Bin  , Wang Shou-Jun  , He Min-Qing  , Sheng Zheng-Ming  , Zhang Jie  ,   (1)Depart of physics, Tianshui Normal College, Tianshui 741000, China; (2)Depart of physics, Tianshui Normal College, Tianshui 741000, China;Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; (3)Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; (4)Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China;Department of Physics, Shanghai Jiaotong University, Shanghai 200240, China
Published: December 2020

The broadening mechanisms are investigated for the energy spectrum of ions accelerated by electrostatic shocks in overdense plasmas irradiated by intense ultra-short laser pulses. It is found that the width of the shock-accelerated ion spectrum could be ineluctably broadened by three mechanisms, which are the continuously decreasing speed of the shock front due to the energy dissipation into ions, the collisions between the particles, and the further acceleration by the sheath field at the rear of target where when energetic ions arrive. Other effects, such as effect of driving laser pulse duration, are also studied.
Electronic energy band structures of carbon nanotubeswith spin-orbit coupling interaction
Authors: Dong Quan-Li  , Zhang Jie  , Yang Jie  , Jiang Zhao-Tan  ,   (1)Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; (2)Department of Physics, Beijing Institute of Technology, Beijing 100081, China
Published: December 2020

Based on the symmetry adapted tight-binding model, the electronic energy band structures of single wall carbon nanotubes are calculated by considering the spin-orbit coupling interaction. The energy gaps at the Dirac point for the armchair nanotubes are formed due to the spin-orbit coupling interaction and the curvature effect. For the zigzag and chiral carbon nanotubes,the energy band splittings for the lowest unoccupied states and the highest occupied states are also formed by the spin-orbit coupling interaction. The energy splittings are not only dependedent on the diameter and the chiral angle of the carbon nanotubes, but also a symmetric with respect to the Fermi energy level. According to the chiral index (n, m), different tube behaviors are grouped into three families. The numeral results are in good agreement with the experimental results.
Monte Carlo simulation of hard X-ray producedby suprathermal electrons interactionwith golden hohlraum targets
Authors: Zhao Xue-Feng  , Li San-Wei  , Jiang Gang  , Wang Chuan-Ke  , Li Zhi-Chao  , Hu Feng  , Li Chao-Guang  ,   (1)Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, China; (2)Research Center of Laser Fusion, CAEP, Mianyang 621900, China; (3)Research Center of Laser Fusion, CAEP, Mianyang 621900, China;Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, China
Published: December 2020

The interaction between laser and hohlraum can generate a large number of suprathermal electrons which obey the Maxwell distribution. The transport properties of the hot electrons and the suprathermal electrons in the hohlraum are investigated by using the Monte Carlo simulation program. In this paper we give the variations of hard X-ray spectrum with hot electrons and suprathermal electrons temperature and fraction, hohlraum size, and hohlraum thickness, and the determinant of efficiency of hard X-ray is obtained. The combination of Monte Carlo program and hot electrons induced by hard X-ray demonstrates the accuracy of the initial hot electrons.
Study of structure evolution of (C60)N clusters usingLennard-Jones atom-atom potential
Authors: Wu Yang  , Duan Hai-Ming  ,   College of Physical Science and Technology,Xinjiang University,Urumqi 830046,China
Published: December 2020

In this paper, we use the Lennard-Jones atom-atom potential to describe the interaction between C60 molecules in (C60)N clusters. Considering the orientation of each C60 molecule,we have calculated the energies of the closed-shell (C60)N(Ni.e., IH,fcc,hcp,DH and SC. Our results show that the IH structure is the most stable one in a small size (NNN60 )N clusters decrease monotonically for the four typical structures of IH, fcc, hcp and DH,but the average molecular energy changes irregularly for the SC structure which undergoes structural reconstruction,implying that the SC (C60)N clusters are unstable in the size range investigated,and the lowest-energy structures of those (C60)N clusters are still far from their crystal forms.
Elastic and thermodynamic properties of CaPo under pressure via first-principles calculations
Authors: Li Xiao-Feng  , Liu Zhong-Li  , Peng Wei-Min  , Zhao A-Ke  ,   College of Physics and Electronic Information, Luoyang Normal University, Luoyang 471022, China
Published: December 2020

We investigate the phase transition pressure, elastic and thermodynamic properties of CaPo by the first-principles plane wave pseudo-potential method in the framework of density functional theory. By the isoenthalpy principle, the phase transition pressure from B1 structure to B2 structure is found to be about 22.8GPa. From the high pressure elastic constants obtained, we find that the B1 structure CaPo is unstable when the applied pressure is larger than 20 GPa, which is in good agreement with the results from the isoenthalpy principle. Moreover, the thermodynamic properties of pressure and temperature of B1 structure CaPo(including specific heat capacity, the Debye temperature, thermal expansion and Grüneisen parameter) are also successfully obtained.
First-principles study of Zn,O codoped p-type AlN
Authors: Yuan Di  , Luo Hua-Feng  , Huang Duo-Hui  , Wang Fan-Hou  ,   (1)Computational Physics Key Laboratory of Sichuan Province, Yibin University, Yibin 644007, China; (2)Computational Physics Key Laboratory of Sichuan Province, Yibin University, Yibin 644007, China;Department of Physics and Electronic Engineering, Yibin University, Yibin 644007, China
Published: December 2020

The electronic structures of pure, Zn doped, and Zn, O codoped wurtzite AlN are calculated by using first-principles ultrasoft pseudopotential approach to the plane wave based on the density functional theory, and the crystal structure, the energy bands, the electronic density of states, the differential charge distribution and the charge population. The results show that in the Zn, O codoped method, the introduction of active donator, atom O, causes acceptor energy level to shift toward low energy, thereby forming the energy levels of shallow acceptor. At the same time, the energy band widens and nonlocal characteristics become significant, thereby increasing the doping concentration of Zn atoms and the stability of the system. Zn, O codoping is more conducible to obtaining the p-type AlN.
Correlation property and electronic transfer propertyof Cantor-styled artificial DNA sequence
Authors: Liu Xiao-Liang  , Liang Liang-Wen  , Xu Hui  , Li Jiang  ,   Institute of Super Microstructure and Ultrafast Process, College of Physics Science and Technology, Central South University, Changsha 410083, China
Published: December 2020

For the Cantor-styled artificial DNA sequence constructed by following the inflation rule A→ABA and B→BBB, using the one-dimensional random walk model and Hurst analysis, we calculate numerically the displacement and its standard deviation, the rescaled range function and the Hurst exponent. The results are compared with those of one-dimensional random binary sequence. We show that Cantor-styled DNA sequence presents correlated behavior, scaling invariability, and self-similarity. In addition, according to the renormalization-group method, we study the charge transfer properties of Cantor-styled DNA sequence, including localization length, charge transmission coefficient and Lyapunov exponent. We find that some resonant peaks can survive in relatively long Cantor-styled DNA sequences, which also implies that there are long-range correlations in Cantor-styled DNA sequences.
Annealing treatment effects on the performances of solar cells based on different solvent blend systems
Authors: Yu Huang-Zhong  , Zhou Xiao-Ming  , Deng Jun-Yu  ,   (1)Department of Physics, South China University of Technology, Guangzhou 510640, China; (2)Department of Physics, South China University of Technology, Guangzhou 510640, China;Key Laboratory of Renewable Energy and Gas Hydrate,Chinese Academy of Sciences, Guangzhou 510632, China;Key Laboratory of Renewable Energy and Gas Hydrate,Chinese Academy
Published: December 2020

The solar cells based on different solvent blends of poly(3-hexylthiophene) (P3HT) and -phenyl C61-butyric acid methyl ester (PCBM) as acceptors are fabricated. Annealing treatment effects on the performances of solar cells based on different solvent blend systems are analyzed by UV-vis absorption spectroscopy and photoluminescence (PL) spectroscopy. The results show that high boiling point solvent leads to an enhanced P3HT ordering in the P3HT:PCBM blend system, and causes an increased incident light absorption and PL spectrum, which contributes to the enhancement of device performance. After 130 ℃ thermal annealing, The UV-Vis absorption, PL spectrum and the performance of the device are further enhanced. The performance of the device prepared with low boiling point chloroform solvent increases obviously after thermal annealing. The solar cell prepared with chlorobenzene solvent after 130 ℃ thermal annealing achieves an open circuit voltage(Voc)of 0.57 V, short circuit current density(Isc)of 8.74 mA/cm2, fill factor (FF ) of 59.2% and power conversion efficiency (PCE) of 2.95% under 100 mW/cm2 air-mass 1.5 solar simulator illumination.
Effects of nitrogen in Stone-Wales defect on the electronic structure and optical property of single-wall carbon nanotube
Authors: Hu Hui-Fang  , Wang Zhi-Yong  , Chen Nan-Ting  , Xie Neng  , Lin Bing-Bing  , Zhang Li-Juan  ,   (1)College of Physics and Microelectronic Sciences, Hunan University, Changsha 410082, China; (2)Lab Center of Zhongshan Campus, Guangdong Pharmaceutical University, Zhongshan 528458, China
Published: December 2020

The effects of nitrogen substitutional doping in Stone-Wales (SW) defect on the electronic structure and the optical property of single-walled nanotube are simulated by using the density functional theory based on the first-principles. It is found that the system energy reduces and binding becomes stabler, and the nitrogen in SW produces a semi-full band near the Fermi level in which the electron effective mass varies with the changing of the position of nitrogen. The absorption and the reflectivity weakened obviously and absorption and reflection peak are both redshifted in the lower energy region. There is a distinct peak at the energy less than 11eV.The results are discussed theoretically. The nitrogen doping and SW defect of carbon nanotubes are expected to provide a theoretical basis for the photoelectric material applications.
Charged excitons in parabolic quantum-well wires under magnetic filed
Authors: Liu Jian  , Zhang Hong  , Zhang Chun-Yuan  , Zhang Hui-Liang  ,   (1)College of Physical Science and Information Engineering, Hebei Normal University, Shijiazhuang 050016, China; (2)College of Science, Hebei University of Engineering, Handan 056038, China
Published: December 2020

The binding energies of the charged excitons(negative X- and positive X+ excitons) are calculated using the finite-difference method within the quasi-one-dimensional effective potential model. The effects due to the magnetic filed and quantum confinements on the binding energy are analyzed, and the following results are obtained:(1) relative electron and hole harmonic oscillator confinement each have a strong effect on the stablity of charged excitons, the binding energy of X+ is not always larger than that of X-, e.g., due to the increase of the hole harmonic oscillator length, leading to the crossing of X+ and X- lines as recently observed experimentally;(2) the magnetic field leads to an increase of the binding energy, and the magnetic field dependence of the binding energy is related to the harmonic oscillator length.
Conductance of single-electron transistor with single island
Authors: Sui Bing-Cai  , Fang Liang  , Zhang Chao  ,   PDL, School of Computer, National University of Defense Technology, Changsha 410073, China
Published: December 2020

With the decrease of the feature size of MOS based circuits, the power consumption of micro-processors has dramatically increased during the last decade, which now mainly restricts the development of the micro-processors.Single-electronic transistors (SETs) are considered as the attractive candidates for post-COMS VLSI due to their ultra-small size and low power consumption.Based on Orthodox theory,the model of conductance is investigated in detail.The conductance of SET with single island is in damped oscillation with a period of T(Vds), and it is close to an intrisical value with the increase of |Vds|. This characteristic of Gds is affected by temperature, parameters of junctions, and so on. The results show that the analysis of conductance is very useful for the very large scale integration of SET devices.
Fabrication, temperature-conductance and photoconductance characteristics of the macroscopic-long Ag2S nanowire bundle
Authors: Xu Jia  , Dong Zhan-Min  , Li Yi  , Sun Jia-Lin  , Sun Hong-San  ,   (1)Department of Physics Tsinghua University, Beijing 100084, China; (2)School of Architecture Tsinghua University, Beijing 100084, China
Published: December 2020

According to the macroscopic-long Ag nanowire bundle which is prepared by the solid-state ionics method, we fabricate a macroscopic-long Ag2S nanowire bundle using a gas-solid reaction. Their morphologies and components are characterized by the SEM, TEM, EDS and XPS. Au paints as electrodes are coated on both ends of a cm-long Ag2S nanowire bundle and then connected to an external circuit. The transport properties of the Ag2S nanowire bundle are studied at different temperatures or under the light irradiation of different wavelengths. Without light irradiation, as temperature T increases from 144 K to 380 K, the dark conductance increases nonlinearly with T. At room temperature, the significant positive photoconductivity induced by the 532 nm or 1064 nm laser is observed. These results demonstrate that Ag2S nanowire is a kind of ideal material for making the nanoscale temperature and photoelectric sensors.
Magnetism and phonon softening of LiFeAs superconductors
Authors: Xing Zhong-Wen  , Liu Mei  , Li Bin  ,   (1)Department of Materials Science and Engineering, Nanjing University, Nanjing 210093, China; (2)Department of Physics, Southeast University, Nanjing 211189,China
Published: December 2020

Using the first principles calculations based on density functional theory, we study the electronic band structure, the phonon dispersion, and the phonon density of states of the iron-based superconductor LiFeAs. The obtained ground state of LiFeAs is of the fluctuated antiferromagnetic order and partial structural relaxation. A comparson of phonon densities of states between in the striped antiferromagnetic ordering and in the nonmagnetic state indicates that the anisotropic spin interactions result in phonon softening of Fe and As atomic vibrations, thereby enhancing the electron-phonon coupling. As a result, the spin-phonon interaction plas an important role in the unconventional superconductivity.
Terahertz wave propagation of one-dimensional antiferromagnetic/dielectric qusi-periodic photonic crystals
Authors: Zhao Yu-Tian  , Zhang Qiang  , Bai Jing  , Fu Shu-Fang  , Zhou Sheng  ,   Heilongjiang Key Laboratory for Low-Dimensional System and Mesoscopic Physics, School of Physics and Electronic Engineering, Harbin Normal University, Harbin 150025,China
Published: December 2020

The transmission of electromagnetic wave at oblique incidence through an antiferromagnetic/nonmagnetic multilayer with a Fibonacci quasi-periodic sequence is calculated by using the transfer matrix approach. Numerical simulations show that many transmission peaks appear in the band gap. Also more and more transmission peak appear as the number of layers in the sequence increases. In addition, the dependence of transmission peak on dielectric constant of nonmagnetic layer, incident angle and wave polarization is also discussed.
Effects of Co and/or Sn doping on crystal structures and optical properties of ZnO thin films
Authors: Wu Yan-Nan  , Xu Ming  , Wu Ding-Cai  , Dong Cheng-Jun  , Zhang Pei-Pei  , Ji Hong-Xuan  , He Lin  ,   (1)Institute of Solid State Physics and School of Physics and Electronic Engineering, Sichuan Normal University, Chengdu 610068, China; (2)Institute of Solid State Physics and School of Physics and Electronic Engineering, Sichuan Normal University, Chengdu 610068, China;Key Lab of Information Materials of Sichuan Province, South-west University for Nationalities, Chengdu 610041, China
Published: December 2020

The Co and/or Sn doped ZnO thin films are deposited on the glass substrates by the sol-gel method. The effects of Co and/or Sn doping on surface morphologies and mircrostructures of ZnO films are investigated by metallurgical microscope and X-ray diffraction (XRD). The XRD results indicate that all the ZnO samples show preferential orientation along the (002) direction, and that the Sn-doped ZnO thin film exhibits the best c-axis orientation and largest grain size. XPS results reveal that Co and Sn elements exist as Co2+ and Sn4+, indicating that Co and Sn ions have entered into the ZnO crystal lattices successfully. Strong blue double emission and weak green emission are observed in the PL spectra of all the samples. In addition, the ultraviolet peaks appear in the undoped and the Co-doped ZnO thin films. Our results reveal that the Co and/or Sn doping can tune the band gap, meanwhile, such a doping can also affect oxygen dislocation, zinc oxygen and zinc interstial defect concentrations. Finally, the possible luminescence mechanisms of Co and/or Sn doped ZnO films are discussed.
Performance of power omnidirectimal reflector LED
Authors: Dong Ya-Juan  , Zhang Jun-Bing  , Chen Hai-Tao  , Zeng Xiang-Hua  ,   College of Physics & Technology, Yangzhou University, Yangzhou 225002, China
Published: December 2020

In this paper, GaN-based InGaN/GaN MQW power LEDs are fabricated based on the existing technology through a simple processing, and their optical, electrical, and color properties are tested. Results show that the luminous intensity of the chips with omnidirectional reflector(ODR) has an improvement of 244mcd over that with the ordinary chips, and that the ODR LED's luminous flux, the efficiency and the color purity are improved by 6.04%, 5.74%, 78.64% respectively. One of the advantages of the ODR LED is its low color temperature, which is greatly lower than that of the ordinary LED.
Up-conversion sensitization luminescence in Pr3+and Yb3+ co-doped fluoride glasses
Authors: Liu Ming-Yang  , Sun Wei-Jin  ,   Department of Fundamental Courses, Academy of Armored Force Engineering, Beijing 100072, China
Published: December 2020

In experiment, Pr3+,Yb3+:ZBLAN glass is chosen as a frequency up-conversion fluorescence material, and detailed reasons for choosing ZBLAN glass as a material are given. In this paper we also analyze the relations between up-conversion fluorescence intensity and pump light intensity and between up-conversion fluorescence intensity and ions doped concentration. Therefore we obtain experimental conditions to realize a clear two-frequency up-conversion 3-D display.
A novel alternant-stripe white light emitting device
Authors: Duan Yu  , Chen Ping  , Zhao Yi  , Liu Shi-Yong  ,   State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012, China
Published: December 2020

White organic light-emitting devices (WOLEDs) have a few technical merits for lighting application. Generally, doping-concentration and carriers-transporting effect inherent in traditional WOLEDs, however, complicate the optimization of device efficiency and color-stability characteristics. In this paper, we design and fabricate a novel WOLED concept,in which an alternant yellow and blue lighting stripe structure is used. We analyze the emission characteristic of this alternate stripe WOLED (AS-WOLED) as a function of yellow and blue stripe size and lighting angle. From the comprehensive analysis, trend in the dependence of emission characteristic on device structure is extracted, and accordingly, a general method for optimizing color characteristics of AS-WOLEDs is suggested.
Comprehensive Survey for the Frontier Disciplines
Authors: Chen Ying-Tian  , T. H. Ho  ,   Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing 100190, China
Published: December 2020

Among others, the removal of boron is the key issue to effectively purify metallurgical silicon into solar grade silicon. An innovative slagging process is proposed in this article after reviewing many previous studies. In the process, strong radiation is employed as catalysis to promote the chemical reaction. The authors have for the first time unveiled the secrets including the newly developed high temperature tools, the materials used, the method of mixing materials before purification, the process for separating silicon from residuals after purification, etc.. In the meantime, the authors also propose a postulate to explain the mechanism of the catalysis process. Except the removal of boron, the processes to remove other impurities, such as phosphorous and residual metals using electron beam and magnetic floating directional solidification are also discussed for the completion of a new industrial process to fabricate pure silicon. In the article, the authors also extend their discussion to the possibility of using the proposed non-imaging heliostat in other fields; to the possibility to further manufacture electronic grade silicon using the same process; to the possibility to obtain more experimental evidences for the postulate of strong radiation catalysis and to other subjects related to authors' claimed creations. It is sincerely hoped that the publication of the innovations reported in this article may provide an alternative way in the route map for the use of renewable energy of low cost and low carbon emission.
Improvement on thermal stability of power heterojunction bipolar transistor using non-uniform finger spacing
Authors: Chen Liang  , Zhang Wan-Rong  , Jin Dong-Yue  , Xie Hong-Yun  , Xiao Ying  , Wang Ren-Qing  , Ding Chun-Bao  ,   College of Electronic and Control Engineering, Beijing University of Technology, Beijing 100124, China
Published: December 2020

One method of non-uniform finger spacing is proposed to enhance thermal stability of multiple finger power heterojunction bipolar transistor. Using coupling thermal resistance to characterize the influence of the change of emitter spacing on thermal coupling, the relation between coupling thermal resistance and emitter spacing is obtained. Temperature distribution on the emitter fingers of multi-finger heterojunction bipolar transistor is studied by a numerical electro-thermal model. The results show that the heterojunction bipolar transistor with non-uniform finger spacing has a smaller temperature difference between fingers thant the traditional uniform finger spacing heterojunction bipolar transistor under the same power dissipation. So the method of non-uniform finger spacing is very effective to enhance the thermal stability.
A collector space charge region model for SiGe HBT on thin-film SOI
Authors: Xu Xiao-Bo  , Zhang He-Ming  , Hu Hui-Yong  , Xu Li-Jun  , Ma Jian-Li  ,   Key Laboratory for Wide Band-Gap Semiconductor Materials and Devices, School of Microelectronics, Xidian University, Xi'an 710071, China
Published: December 2020

SiGe heterojunction bipolar transistor (HBT) on thin film SOI has been successfully integrated with SOI CMOS by "folded collector". This paper deals with the collector of "partially depleted transistor" according to the thin film vertical SiGe HBT structure. A simplified circuit model including vertical and horizontal resistors and depletion capacitance is presented for the first time, and the model of the collector for field, voltage, and depletion width is systematically established. The model is analyzed with reasonable parameters. The results indicate that the space charge region consists of intrinsic junction depletion and MOS capacitance depletion, that the width of the space charge region increases with doping concentration of the collector, larger reverse junction voltage, and smaller substrate voltage, and that the region features a vertical expansion followed by a lateral expansion. This space charge region model of collector provides a valuable reference to the SiGe mm-wave BiCMOS circuit design and simulation on thin film SOI.
Energies, electronic structures and magnetic properties of Ni atomic chain encapsulated in carbon nanotubes: a first-principles calculation
Authors: Li Shu-Li  , Zhang Jian-Min  ,   (1)College of Physics and Information Technology, Shaanxi Normal University, Xi'an 710062, China; (2)College of Physics and Information Technology, Shaanxi Normal University, Xi'an 710062, China;Department of Physics,Xian University of Arts and Science, Xi’an 710065,China
Published: December 2020

In the generalized gradient approximation (GGA), energies, electronic structures and magnetic properties have been investigated for a single Ni atomic chain encapsulated in an armchair single-wall (n,n) carbon nanotubes (5≤n≤9) by using the first-principles projector augmented wave (PAW) potential within the density function theory (DFT) framework. The results show that the (5,5) tube is too narrow to wrap a Ni atomic chain, but the (6,6) tube is the smallest one to wrap a Ni atomic chain, especially at its central axis due to the lowest formation energy. The analyses of the spin-polarized band structures, total density of states (DOS), partial density of states (PDOS) and the magnetic moment of Ni@(6,6) and Ni@(7,7) systems show that the 3d states of Ni atom play determinant rales in DOS at the Fermi level, and the broader carbon nanotubes restrict slightly the magnetic moment of Ni atomic chain compared with with the narrower ones.
Influence of PEDOT:PSS film doped with sorbitol on performances of organic solar cells
Authors: Liu Jun-Cheng  , Gao Cong-Jie  , Li Jiao  ,   (1)College of Chemistry and Chemical Engineering , Ocean University of China, Qingdao 266100, China; (2)School of Materials Science and Engineering, Shandong University of Technology, Zibo 255049, China; (3)School of Materials Science and Engineering, Shandong University of Technology, Zibo 255049, China;College of Chemistry and Chemical Engineering , Ocean University of China, Qingdao 266100, China
Published: December 2020

In this article, the PEDOT:PSS doped with sorbitol film is fabricated on an ITO substrate by blending-spin coating method and used as a hole-extraction layer for organic solar cell (OSC). The effect of sorbitol concentration on the photovoltaic performance of the device is investigated based on P3HT:PCBM blend. Compared with a pristine device (i.e., without sorbitol), the sorbitol-doped (8wt %) OSC shows that the short-circuit current density, the fill factor and the power conversion efficiency are inereased from 8.82 to 9.03mA/cm2, 0.43 to 0.474 and 2.12% to 2.39 % (i.e., by about 13%), respectively. The canse of the improvement on performance of the device is discussed, showing that the increase in conductivity and transmittance of composite films is due to the improvement on OSC performances achieved through the incorporation of sorbitol into hole-extraction layer of PEDOT:PSS. The former leads to a lower series resistance of the device, while the latter gives rise to the improvement on the photo-induced carriers of the photovoltaics cells.
Capability of resisting γ-ray irradiation and Rietveld structurerefinement of zircon
Authors: Zhang Dong  , Lu Xi-Rui  , Yang Yan-Kai  , Cui Chun-Long  , Chen Meng-Jun  ,   (1)Institute of Nuclear Physics and Chemistry, CAEP, Mianyang 621900, China; (2)National Defense Key Discipline Lab of Nuclear Waste and Environmental Safety, SWUST, Mianyang 621010, China
Published: December 2020

In order to investigate the structural stability for zircon in mothball waste form of radionuclide to resist γ-ray irradiation, the zircon crystals, which are collected from Australia, are studied. The crystal grains are irradiated by a60Co γ-ray source with 1728 kGy doses. The chemical compositions of zircons are analyzed by X-ray fluorescence spectrometry (XRF). Moreover, phases, structures and microstructures of the samples before and after γ-ray irradiation are characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results indicate that the new phases are not found in the crystals before and after γ-ray irradiation with 1728 kGy. The crystal cell parameters change by 10-4 before and after irradiation. Moreover, no obvious damage to the structure is found in the zircon irradiated by γ-ray with 1728 kGy dose. So, the zircon possesses a better capability to resist γ-ray irradiation which hardly influence the degree of disorder for zircon.
Optimal traffic routing strategy based on community structure
Authors: Shao Fei  , Jiang Guo-Ping  ,   (1)Center for Control and Intelligence Technology, Nanjing University of Posts and Telecommunications, Nanjing 210003, China; (2)Center for Control and Intelligence Technology, Nanjing University of Posts and Telecommunications, Nanjing 210003, China;Department of Information Technology, Jinling Institute of Technology, Nanjing 211169, China
Published: December 2020

It is shown that community structure has great influence on traffic transportation. Networks with pronounced community structure are less efficient in terms of packet delivery. While the shortest path is chosen at random in the shortest path routing strategy, a routing strategy based on community structure is proposed in this paper which can reduce the betweenness centrality of the nodes on the edge of the community by minimizing the number of the communities that the shortest path passes through. Simulations show that the new strategy can enhance the packet delivery capability with the small-world character and that the more accurately the community is identified, the more efficient the new strategy is.
Lightning M-components with peak currents of kilo amperes and their mechanism
Authors: Jiang Ru-Bin  , Qie Xiu-Shu  , Wang Cai-Xia  , Yang Jing  , Zhang Qi-Lin  , Liu Ming-Yuan  , Wang Jun-Fang  , Liu Dong-Xia  , Pan Lun-Xiang  ,   Department of Lightning Science and Technology, College of Remote Sensing, Nanjing University of Information Science and Technology, Nanjing 210044,China;,   Key Laboratory of Middle Atmosphere and Global Environment observation, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029,China;,   Key Laboratory of Middle Atmosphere and Global Environment observation, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029,China;Graduate School, Chinese Academy of Sciences, Beijing 100049,China
Published: December 2020

Characteristics of six M-components with peak currents of kilo amperes are analyzed by using the data from the artificially triggering lightning experiment in Shandong 2009, including the current at the base of the discharge channel, the surface electric field change at 30 m from the channel, and the high-speed camera records. The M-component is associated with the abrupt enhancement of channel luminosity with a duration of less than 1ms. Both the current and electric field are characteristic of relatively symmetric waveforms with a rise time of several tens of microseconds. The simultaneous records show that the electric field starts to change and reaches its peak earlier than the channel base current. Because of the obvious continuing current flowing in the channel, the conductivity of the discharge channel prior to the M-component is better than that prior to the leader-return strokes. The channel condition before the occurrence of the M-component is crucial to current amplitude and rise time. According to the waveforms of current and electric field recorded simultaneously, it is inferred that the M-component evolves from up to down and the evolvement continues after contacting the ground, and then an upward reflected process is induced. Further analysis shows that the interaction between these two processes is likely to be changed with altitude.
Regularization method of assimilating Doppler radar data and its influence on precipitation forecast
Authors: Huang Si-Xun  , Du Hua-Dong  , Zhong Ji-Qin  , Zhao Yan-Lai  ,   (1)Institute of Meteorology, PLA University of Science and Technology, Nanjing 211101, China; (2)Institute of Urban Meteorology, China Meteorological Administration, Beijing 100089, China
Published: December 2020

A new regularization method is proposed to directly assimilate Doppler radar data into mesoscale numerical weather forecast based on the traditional 3DVAR. For seeking the minimum module solution of the Yo=H(X) with bias δ, the regularization method is adopted and leads to a new cost function. A group of experiments were designed to study the case of a locally strong rainstorm occurred in Beijing area on August 14, 2008. The L-curve principle is used to determine the optimal regularization parameter and the result is α=0.1. Numerical results demonstrate that both regularization method and 3DVAR scheme can efficiently assimilate the Doppler radar data, and that the improved initial condition can alleviate the spin-up phenomenon and improve the nowcasting precipitation forecast. However, when an optimal regularization parameter is choser, better improvement, more accurate precipitation forecast and higher TS score are expected.
Cognitive radio resource allocation based on combined chaotic genetic algorithm
Authors: Zu Yun-Xiao  , Zhou Jie  ,   School of Electronic Engineering, Beijng University of Posts and Telecommunications, Beijing 100876, China
Published: December 2020

The combined chaotic genetic algorithm for cognitive radio resource allocation is proposed, and corresponding combined chaotic sequence generator is designed. Simulations are conducted by using the combined chaotic genetic algorithm, the particle swarm optimization algorithm, the simulated annealing algorithm, and the simple genetic algorithm, thereby analyzing the multi-users, cognitive radio resource allocation. The results show that the combined chaotic genetic algorithm has advantages of fast convergence rate, vast search space and global convergence. The combined chaotic genetic algorithm has better performance than the other three algorithms in terms of cognitive radio resource allocation, there by reducing the bit error rate and the transmission power consumption of the system. Besides, it also has a faster convergence rate.
Fidelity of the photon subtracted (or added) squeezed vacuum state and squeezed cat state
Authors: Lü Jing-Fen  , Ma Shan-Jun  ,   College of Physics and Communication Electronics, Jiangxi Normal University, Nanchang 330022, China
Published: December 2020

In this paper, the fidelity of photon subtracted (or added) squeezed vacuum state with arbitrary number of photons and squeezed cat state is derived analytically. The result shows that whether the photon is added or subtracted, the maximum fidelity increases with the increase of the change of photon number, and the amplitude of the superposition state corresponding to the maximum fidelity also increases. In addition, for the same number of subtracted or added photons, the amplitude of the superposition state corresponding to the maximum fidelity in the case of added photon is larger than in the case of subtracted photon, but the maximum fidelity in the case is smaller. Although it is more difficult to make photon added than photon subtracted the photon added can be used as an important method to obtain cat state of large amplitude.
Arbitrated quantum signature scheme based on entanglement swapping
Authors: Li Wei  , Fan Ming-Yu  , Wang Guang-Wei  ,   School of Computer Science and Engineering, University of Electronic Science and Technology of China, Chengdu 610054, China
Published: December 2020

An arbitrated quantum signature scheme based on entanglement swapping is proposed in this paper. On the foundation of Bell states, the message to be signed is coded with a unitary sequence, and consequently the unitary sequence is used to calibrate the Bell states between the signer and the arbitrator, finally the signature is generated through quantum cryptography. Using the correlation states generated through entanglement swapping on the arbitrators side, the receiver can verify the signature through Bell measurement on his own side. In this scheme, anyone except the authentic signer cannot forge a legal signature and the true receiver cannot deny his recipient because the security of underling quantum cryptography and the participantsprivacy are effectively protected in this scheme.
The brick-wall model unapplicable to the calculating of black hole entropy
Authors: Yang Xue-Jun  , Zhao Zheng  ,   Department of Physics and Electronic Information, Shaoxing University of Arts and Sciences, Shaoxing 312000, China;,   Department of Physics, Beijing Normal University, Beijing 100875, China
Published: December 2020

The brick-wall model is widely used to calculate the entropies of static or stationary black holes. An ultraviolet cutoff factor needs to be introduced to remove the divergence of the result in brick-wall model. The cutoff factor has not been explained reasonably up to now. A study indicated that when the brick-wall model or thin film model was used to calculate the black hole entropy, the ultraviolet cutoff factor could be discarded if the generalized uncertainty relation was adopted. In this paper, it is proved that since the first term of Schwarzschild black hole entropy formula in the brick-wall model is not only the Bekenstein-Hawking term but also the term containing the ultraviolet cutoff factor, when the cutoff factor is removed, the Bekenstein-Hawking term is lost and the black hole entropy cannot be obtained by using the generalized uncertainty relation in brick-wall model.
Merging crisis of chaotic saddle in a Duffing unilateral vibro-impact system
Authors: Feng Jin-Qian  , Xu Wei  ,   School of Science, Xi'an Polytechnic University, Xi'an 710048, China;,   College of Science, Northwestern Polytechnical University, Xi'an 710072, China
Published: December 2020

A computational investigation of chaotic saddles in a Duffing vibro-impact system is presented. Chaoctic saddle crisis is investigated in a duffing vibro-impact system considered. This crisis is due to the tangency of the stable and unstable manifolds of period saddle connecting two chaotic saddles. The threshold of tangency induces the merging crisis of chaotic saddle, that is, as the system parameter crosses the critical value, a larger boundary chaotic saddle appears due to the merging of two chaotic saddles located on the basin boundary and in the internal basin respectively. In fact, this chaotic saddle crisis is responsible for the merging crisis of chaotic attractors eventually.
Selective forgetting extreme learning machine and its application to time series prediction
Authors: Zhang Xian  , Wang Hong-Li  ,   Department of Automatic Control Engineering, The Second Artillery Engineering College, Xi’an 710025, China
Published: December 2020

To solve the problem of extreme learning machine (ELM) on-line training with sequential training samples, a new algorithm called selective forgetting extreme learning machine (SF-ELM) is proposed and applied to chaotic time series prediction. The SF-ELM adopts the latest training sample and weights the old training samples iteratively to insure that the influence of the old training samples is weakened. The output weight of the SF-ELM is determined recursively during on-line training procedure according to its generalization performance. Numerical experiments on chaotic time series on-line prediction indicate that the SF-ELM is an effective on-line training version of ELM. In comparison with on-line sequential extreme learning machine, the SF-ELM has better performance in the sense of computational cost and prediction accuracy.
Cellular automaton simulation with directed small-world networks for the dynamical behaviors of spiral waves
Authors: Tian Chang-Hai  , Deng Min-Yi  , Kong Ling-Jiang  , Liu Mu-Ren  ,   College of Physics and Technology, Guangxi Normal University, Guilin 541004, China;,   College of Physics and Electronic Engineering, Guangxi Teachers Education University, Nanning 530000, China
Published: December 2020

In this paper, we study the influence of the rewiring probability p of the directed small-world network on dynamical behavior of spiral wave using the Greenberg-Hastings cellular automaton model. The computer simulation results show that when p is small enough, the stable spiral wave under the regular networks keeps its stability unchanged, and when p is increased, the phenomenon such as meandering, breakup and disappearance of the spiral waves appears. The relation between the excitability and p leads to the conclusion that the occurrence of the above phenomenon originates from the reducing of the excitability. On the other hand, the period of cell is also related to p.
Spread spectrum communication based on hardware encryption
Authors: Xiao Bao-Jin  , Tong Hai-Li  , Zhang Jian-Zhong  , Zhang Chao-Xia  , Wang Yun-Cai  ,   Department of Information and Communication, Taiyuan University of Technology, Taiyuan 030024, China;,   Department of Physics and Optoelectronics, Taiyuan University of Technology, Taiyuan 030024, China;,   State Key Laboratory of Quantum Optics and Quantum Optics Devices, Shanxi University, Taiyuan 030006, China
Published: December 2020

The scheme of 1 Gbit/s random sequence generated by chaotic laser as spreading code is proposed. Theoretical analysis indicates that the pseudo random sequence exhibited periodic behavior is eliminated by the random sequence and the capability of spreading code is enlarged. Meanwhile, the communication security can be improved by variable spreading code. The corresponding spread spectrum system is numerically simulated by Simulink software and the results demonstrate that the greater the used spreading gain, the lower the obtained error rate will be when the information speed is constant, which is consistent with the theoretical results. The anti-jamming ability of the spread spectrum system is strengthened and the security is enhanced compared with those of the traditional spreading system.
Modified function projective synchronization of a class of chaotic systems
Authors: Li Jian-Fen  , Li Nong  ,   College of Science, Air Force Engineering University, Xi'an 710051, China;,   College of Engineering, Air Force Engineering University, Xi'an 710038, China
Published: December 2020

A general method of modifying function projective synchronization of a class of chaotic systems is proposed in this paper by designing a suitable response system. The two schemes of obtaining the response system from chaotic system are established based on unidirectional coupled synchronization. Since chaos synchronization can be achieved by transmitting only a single variable from driving system to response system, this method is more practical. The stability analysis in the paper is proved using Lyapunov stability theory. Numerical simulations of a hyperchaotic system verify the effectiveness of the proposed method.
Considering two-velocity difference effect for coupled map car-following model
Authors: Ge Hong-Xia  , Cheng Rong-Jun  , Li Zhi-Peng  ,   Faculty of Science, Ningbo University, Ningbo 315211, China;,   Department of Fundamental Course, Ningbo Institute of Technology, Zhejiang University, Ningbo 315100, China;,   College of Electronics and Information Engineering, Tongji University, Shanghai 200092, China
Published: December 2020

Based on the pioneer work of Konishi et al, a new coupled map car-following model is presented by considering the headway distance of two successive vehicles in front. The feedback control method presented by Zhao-Gao is utilized to suppress the traffic congestion in the coupled map car-following model. According to the control theory, the condition under which the traffic jam can be suppressed is analyzed. The results are compared with that presented by Konishi et al. The simulation results show that the new model with the feedback control method presented by Zhao-Gao could suppress the traffic jam effectively.
Epidemic spreading in complex networks with spreading delay based on cellular automata
Authors: Wang Ya-Qi  , Jiang Guo-Ping  ,   College of Automation, Nanjing University of Posts and Telecommunications, Nanjing 210003, China
Published: December 2020

In this paper, based on the cellular automata, we propose a new susceptible-infected-susceptible (SIS) model to study epidemic spreading in the networks with spreading delay. Theoretical analysis and simulation results show that the existence of spreading delay can significantly reduce the epidemic threshold and enhance the risk of outbreak of epidemics. It is also found that both the epidemic prevalence and the propagation velocity increase obviously with the spreading delay increasing. Moreover, the SIS model proposed in this paper describes not only the average propagation tendency of epidemics, but also the dynamic evolution process over the time of epidemics and the probability events such as outbreak and extinction of epidemics, and thus can overcome the limitations of the differential equation model based on mean-field method that describes only the average transmitting tendency of epidemics. Meanwhile, some suggestions of how to effectively control the propagation of epidemics are presented.
High order harmonic generation from a two-dimensional model H atom in arbitrary polarized laser
Authors: Zhang Chun-Li  , Feng Zhi-Bo  , Qi Yue-Ying  , Che Ji-Xin  ,   College of Electric and Information Engineering, Xuchang University, Xuchang 461000, China;,   Institute of Applied Physics and Computational Mathematics, Beijing 100088, China;,   College of Mathematics, Physics and Information Engineering, Jiaxing University, Jiaxing 314000, China;,   Department of Ordnance Engineering, Aviation University of Air Force, Changchun 130022, China
Published: December 2020

The two-dimensional time-dependent Schrdinger equation of arbitrary polarized laser pulse interacting with a model H atom is solved by using the two-dimensional asymptotic boundary condition (ABC) and symplectic algorithm. In order to investigate the influence of ellipticity on high order harmonic generation (HHG) of atom in arbitrary polarized laser field, we consider different ellipticities, and then compute the HHG for two-dimensional model H atom. Finally, we analyze the characteristics of HHG under different polarized laser fields. So it is reasonable and effective to extend the one-dimensional ABC and symplectic algorithm to the problem of laser interacting with a two-dimensional model atom.