bluuebunny/crossref_metadata_2025 huggingface dataset:
Electronic and magnetic properties of p，n type dopant and Mn co-doped GaN
Authors: Xing Hai-Ying  , Fan Guang-Han  , Zhou Tian-Ming  ,   华南师范大学光电子材料与技术研究所，广州  510631
Published: December 2020

Calculation of electronic structures and magnetic properties of Mg （or Zn＼Si＼O） and Mn co-doped GaN were carried out by means of first-principle plane-wave pesudopotential （PWP） based on density functional theory. Estimation of Curie temperature was achieved by using Heisenberg model in the mean-field approximation and Zener theory，respectively. The spin polarized impurity bands of deep energy levels are found for several co-doped systems, which are half metallic and suitable for spin injectors. Compared with GaN：Mn，p-type co-doped （GaN：Mn-Mg＼Zn） systems exhibit more stable ferromagnetic state and a significant increase in TC. Nevertheless，n-type co-doped （GaN：Mn-Si＼O） systems fail to increase the TC and stability of ferromagnetic state.
Electronic theory study of interface characteristic of magnesium/carbon nanotube with nickel
Authors: Liu Gui-Li  , Yang Zhong-Hua  , Fang Ge-Liang  ,   (1)沈阳工业大学建筑工程学院，沈阳  110023; (2)沈阳师范大学物理科学与技术学院，沈阳  110034
Published: December 2020

The atomic cluster models of Mg/CNT（carbon nanotube or nickel carbon nanotube） interface have been built in magnesium composite reinforced by （nickel） carbon nanotube. The interface electronic structures have been calculated by recursion method. The calculated results show that nickel enhances the stability of nanotube/matrix interface, improves the interface bond strength, since nickel makes the structure energy and atomic binding energy of nanotube/matrix interface lowered. The positive interaction energy of magnesium atoms in nickel film of interface causes the magnesium atoms in nickel film to repel each other and can not form magnesium atomic cluster, so they prefer to form ordering phase which consolidate the interface. The carbon and magnesium atoms have higher energy of position, which causes interface instability and flimsiness at carbon nanotube without nickel plating and magnesium interface. But when the carbon nanotubes have been plated by nickel, the energy of position of carbon and magnesium atoms are made lower and the interface gets more stable and tough.
The structural and electronic properties of the unconventional exohedral fullerene C64Si
Authors: Tang Chun-Mei  , Zhu Wei-Hua  , Deng Kai-Ming  ,   (1)河海大学理学院,南京  210098; (2)河海大学理学院,南京  210098；南京理工大学应用物理系,南京  210094; (3)南京理工大学应用物理系,南京  210094
Published: December 2020

The generalized gradient approximation based on density functional theory is used to analyze the structural and electronic properties of the unconventional exohedral fullerene C64Si. It is found that among four possible stable isomers, the structure with the single Si atom situated at the vertex of the directly fused pentagons, i.e., C64Si-1, is the most stable, which agrees well with the stable position of Si outside the C28 cage proposed by Ge et al. By analyzing the energy levels, orbital wave functions and density of states of both C64 and C64Si-1, Si atom is found to have greater contribution to the lowest unoccupied molecular orbital, but contribute less to the highest occupied molecular orbital. In addition, the effect of Si on the total density of states of C64 is very small. It is found from the vertical ionization potential and the vertical affinity that the ability for both detaching and obtaining electrons is decreased after the exohedral absorbing Si atom.
Spin-dependent transport through a multi-electrodes controlled by an Aharonov-Bohm ring
Authors: Yao Jian-Ming  , Yang Chong  ,   (1)忻州师范学院物理系，忻州  034000; (2)浙江海洋学院物理系，舟山  316000
Published: December 2020

The multi-terminal quantum transport in a dot-array through an AB ring is studied via single-band tight-binding Hamiltonian. It is shown that the output spin current is a periodic function of the magnetic flux in the quantum unit Φ0. Moreover, we can get the spin current with contrary spin polarization in the same energy range in different terminals.
Thickness dependent dislocation, electrical and optical properties in InN films grown by MOCVD
Authors: Zhang Zeng  , Zhang Rong  , Xie Zi-Li  , Liu Bin  , Xiu Xiang-Qian  , Li Yi  , Fu De-Yi  , Lu Hai  , Chen Peng  , Han Ping  , Zheng You-Dou  , Tang Chen-Guang  , Chen Yong-Hai  , Wang Zhan-Guo  ,   (1)半导体材料科学重点实验室，中国科学院半导体研究所，北京  100083; (2)江苏省光电信息功能材料重点实验室，南京大学物理系，南京  210093
Published: December 2020

InN thin films with different thicknesses are grown by metal organic chemical vapor deposition, and the dislocations, electrical and optical properties are investigated. Based on the model of mosaic crystal, by means of X-ray diffraction skew geometry scan, the edge dislocation densities of 4.2×1010cm-2 and 6.3×1010cm-2 are fitted, and the decrease of twist angle and dislocation density in thicker films are observed. The carrier concentrations of 9×1018cm-3 and 1.2×1018cm-3 are obtained by room temperature Hall effect measurement. VN is shown to be the origin of background carriers, and the dependence of concentration and mobility on film thickness is explained. By the analysis of S-shape temperature dependence of photoluminescence peak, the defects induced carrier localization is suggested be involved in the photoluminescence. Taking both the localization and energy band shrinkage effect into account, the localization energies of 5.05meV and 5.58meV for samples of different thicknesses are calculated, and the decrease of the carrier localization effect in the thicker sample can be attributed to the reduction of defects.
Effect of hydrofluoric acid etching time on Ni/6H-SiC contacts
Authors: Huang Wei  , Chen Zhi-Zhan  , Chen Bo-Yuan  , Zhang Jing-Yu  , Yan Cheng-Feng  , Xiao Bing  , Shi Er-Wei  ,   (1)中国科学院上海硅酸盐研究所宽禁带半导体材料课题组，上海  200050; (2)中国科学院上海硅酸盐研究所宽禁带半导体材料课题组，上海  200050；中国科学院研究生院，北京  100049; (3)中国科学院研究生院，北京  100049；中国科学院上海硅酸盐研究所高性能陶瓷和超微结构国家重点实验室，上海  200050
Published: December 2020

The effect of hydrofluoric acid （HF） etching time on Ni/6H-SiC ohmic contacts was investigated． The as-deposited Ni/6H-SiC contacts prepared by 6H-SiC substrates which have been subjected to different HF etching time have different I-V characteristics． For SiC substrates etched for less than 12 hours, the contacts were rectifying, and excellent linear curves were observed after high temperature thermal annealing．X_ray diffraction, Auger electronic spectroscopy and low_energy reflection electron energy loss spectroscopy showed that Ni2Si and amorphous C were the main reaction products after annealing.For SiC substrate etched for 24 hours, the as-deposited Ni/6H-SiC contact was ohmic． The carbon-enriched layer （CEL） on the SiC surface plays an important role in the formation of ohmic contact．
Hole transport in polymer P3HT with different annealing temperatures
Authors: Yin Li-Qin  , Peng Jun-Biao  ,   (1)华南理工大学高分子光电材料与器件研究所,广州  510640; (2)华南理工大学高分子光电材料与器件研究所,广州  510640；华南理工大学特种功能材料及其制备新技术教育部重点实验室,广州  510640
Published: December 2020

Hole only devices were fabricated with the structure of ITO/PEDOT/P3HT （poly（3-hexylthiophene））/Ag. The capacitance-frequency characteristics of samples annealed at different temperatures were investigated by admittance spectroscopy technique. Hole mobilities were calculated and it was found that the hole mobility could be pronouncedly influenced by annealing. The hole mobility was enhanced to the 10-3 cm2/Vs order after annealing, while the hole mobility of the unannealed sample was just of 10-4 cm2/Vs order. The hole mobility of the annealed sample is almost unchanged under different electric field. In contrast, the hole mobility of the annealed sample showed relatively significant change with the electric field.
Numerical simulation of electrical transport characteristics of single layer organic devices
Authors: Hu Yue  , Rao Hai-Bo  ,   电子科技大学光电信息学院,成都  610054
Published: December 2020

A numerical model of organic devices，which includes charge injection, transport, space charge effect and trap influence，was discussed in this paper. Both thermionic emission over the barrier and tunneling through the barrier are considered in charge injection into the bulk. The result is in good agreement with the experimental data. Several parameters have been simulated to study the change of J-V characteristics. The current decreases with the increases of the length of device. The current density becomes higher when the hole injecting barrier is smaller. However, when the electronic injecting barrier decreases from 1.7 eV to 0.5 eV, the current density becomes smaller. This is because the electronic mobility is too small, and the electronic injecting current is negligible compared with the hole current. When the electronic injecting barrier is smaller, the built-in potential becomes bigger, under the same applied voltage, the field diminishes, and the hole current becomes smaller. When the barrier is reduced to 0.1 eV, the current density increases. This is because the electronic mobility is too small, and electrons accumulate near the cathode, the electric field around the anode increases and the current increases.
On the g factors of 2E state for 3d3ions at trigonal symmetry
Authors: Wei Qun  ,   宝鸡文理学院物理系,宝鸡  721007
Published: December 2020

In connection with local structure, the g factors of 2E state are studied by using complete diagonalization method （CDM）, with the spinel type crystals ZnAl2Ｏ4:Cr3＋, ZnGa2Ｏ4:Cr3＋ and MgAl2Ｏ4:Cr3＋ as the cases. The slight magnetic interactions, including spin-spin （SS）, spin-other-orbit （SOO） and orbit-orbit （OO） interactions are taken into account in our investigations. Theoretical explanations of g factors of 2E state for ZnAl2Ｏ4:Cr3＋ have been given. The results show that the sign of g‖（E′） for ZnGa2Ｏ4:Cr3＋ should be negative. And the value of g factors of 2E state for MgAl2Ｏ4:Cr3＋ have been predicted. It is shown that, the contributions to g factors of 2E state from slight magnetic interactions are appreciable. Compared with the g factors of ground state, the g factors of 2E state are sensitive to the local structure.
Preparation of L10-FePt film for perpendicular magnetic recording media by using FePt/Au mutilayers
Authors: Feng Chun  , Zhan Qian  , Li Bao-He  , Teng Jiao  , Li Ming-Hua  , Jiang Yong  , Yu Guang-Hua  ,   (1)北京工商大学数理部,北京  100037; (2)北京科技大学材料物理与化学系,北京  100083
Published: December 2020

FePt/Au mutilayers were deposited on 100℃ MgO（001） single crystal substrate by magnetron sputtering. The influence of the FePt/Au multilayer structure on the ordering temperature, coercivity （ＨC）, perpendicular magnetic anisotropy （PMA）, FePt grain size and interparticle exchange coupling （IEC） of films were studied. Results show that the film possesses high ＨC, excellent PMA, small grain size and weak interparticle exchange coupling after annealing. The results of HRTEM reveal that Au can relieve mismatch between MgO and FePt lattices, leading to excellent PMA. Moreover, the FePt/Au interface energy, the stress energy due to the mismatch between FePt and Au lattices and the diffusion of Au atoms promote the ordering of FePt film. This leads to the decrease of ordering temperature and considerable increase of ＨC. Au atoms partly diffuse to the boundaries of FePt phase and function as grain finer and particle isolator, which decrease the FePt grain size and IEC.
Magnetization reversal of perpendicularly orientated Nd2Fe14B/α-Fe trilayer
Authors: Xian Cheng-Wei  , Zhao Guo-Ping  , Zhang Qing-Xiang  , Xu Jin-Song  ,   (1)四川师范大学物理与电子工程学院和固体物理研究所,成都  610068; (2)四川师范大学物理与电子工程学院和固体物理研究所,成都  610068；电子科技大学，电子薄膜与集成器件国家重点实验室，成都  610054
Published: December 2020

The full magnetization reversal process of perpendicular orientated Nd2Fe14B/α-Fe trilayer has been investigated by using a micromagnetic method. Both nucleation and pinning fields as well as hysteresis loops have been calculated reliably as functions of Ｌs （soft layer thickness）. In addition, detailed comparison between our results and experimental data has been done. With the demagnetization energy considered, the nucleation field of perpendicular by orientated case is lower than the parallel one and the nucleation occus before the reversal of the applied field. For small Ｌs, the theoretical coercivity equals to the nucleation field （it equals to pinning filed also）. As the thickness of the soft phase increases, the coercivity mechanism changes from nucleation to pinning. For large Ｌs, however, the coercivity is slightly smaller than the pinning field.
Numerical analysis of two-dimensional magnetophotonic crystals with structural defects
Authors: Zhang Hao  , Zhao Jian-Lin  , Zhang Xiao-Juan  ,   西北工业大学理学院光信息科学与技术研究所,陕西省光信息技术重点实验室,西安  710072
Published: December 2020

The Faraday rotation of two-dimensional magnetophotonic crystals （including those with fourfold-symmetry and non-fourfold-symmetry） with structural defects and the ellipticity of outgoing optical waves are analyzed by using finite-difference frequency-domain （FDFD） method. The numerical simulation results show that the localization of the light wave in the vicinity of central defect occurs in these types of the structure. With increasing Faraday rotation of fourfold-symmetry structures, the change of the ellipticity of outgoing optical waves from these structures is unobvious. In contrast, the increases of the ellipticity of outgoing optical waves are obvious with the raise of Faraday rotation in non-fourfold-symmetry structures. It is concluded that introducing defects to the fourfold-symmetry structure constrains the change of the state of polarization of optical waves. This kind of two-dimensional magnetophotonic crystal with structural defects may be used to manufacture magnetophotonic crystal fiber.
Zonal flow dynamics in background of ion-temperature-gradient mode turbulence based on minimal freedom model
Authors: Lu He-Lin  , Wang Shun-Jin  ,   四川大学物理科学与技术学院理论物理中心，成都  610064
Published: December 2020

In the ITG (ion-temperature-gradient) mode turbulence background, the dynamics of zonal flow generation is studied based on the minimal freedom model. We study the dynamical instability and present detailed numerical results. The energy cascade process in the ITG mode turbulence and the relationship between Reynolds stress and zonal flow are also discussed. The mechanism of turbulence suppression by zonal flow is clearly explored and displayed.
Effect of Dy on properties of red long-afterglow phosphor Sr3Al2O6:Eu2+,Dy3+
Authors: Cui Cai-E  , Wang Sen  , Huang Ping  ,   太原理工大学理学院,太原  030024
Published: December 2020

The red long afterglow phosphor Sr3Al2O6:Eu2+,Dy3+ was prepared by sol-gel method. The crystal structure was characterized by X-ray diffraction. The results reveal that the samples are composed of single Sr3Al2Ｏ6 phase at 1200℃, and the small amount of doped rare earth ions （Eu2＋ and Dy3＋） has no effect on the Sr3Al2Ｏ6 phase composition. The excitation, emission and afterglow spectra were investigated by fluorescence spectrophotometer technique. The broad excitation spectra in the range of 400—550 nm were found in the Sr3Al2Ｏ6:Eu2＋ and Sr3Al2Ｏ6:Eu2＋,Dy3＋ phosphors. The broad band spectrum is associated with defects and vacancies of host material and the peak at 530.1 nm can be assigned to the recombination of donor-acceptor pairs of Ｄy·Sr-V″Sr from dysprosium doping in the Sr3Al2O6. With the increasing concentration of Dy below 0.03, the emission intensity of Sr3-0．02-yAl2Ｏ6:0.02Eu2＋,yDy3＋ phosphors increases, and the samples exhibit the red light emission spectra with the main emission peak at 612 nm under an excitation of 473 nm. The red emission has a broad-band feature, belonging to the emission of the 4f65d1→4f7 of Eu2＋ions. With the increasing concentration of Dy within the range of 0.03—0.06, there was a new emission peak in the green region, and the emission intensities of the two peaks at 530 nm and 612 nm decrease. The afterglow time of the Sr2．95Al2Ｏ6:0.02Eu2＋,0.03Dy3＋ phosphors lasts 540s（≥1　mcd/m2） after removal of excitation. The Dy3＋ ions are auxiliary activator in the Sr3Al2O6:Eu2+,Dy3+ phosphors.
The fluorescence spectral characteristics and the emission mechanism of ethanol excimer in water solution
Authors: Liu Ying  , Ni Xiao-Wu  ,   (1)徐州师范大学物理与电子工程学院,徐州  221116; (2)徐州师范大学物理与电子工程学院,徐州  221116；南京理工大学理学院,南京  210094
Published: December 2020

The fluorescence spectra of ethanol-water solution excited by UV-light have been studied, in which there is a broad and featureless fluorescence spectrum with the peak at 410 nm. It is considered that when the clustered molecules with a special long chain structure approach each other, the excimer is formed between the excited state and ground state cluster monomers, which can emit fluorescence. According to the experimental result and the energy transfer theory, we know that an electron transfer complex is formed by the excimer and the cluster monomer in the excited state. Based on Mulliken theory and the quantum mechanics theory, the energy of ground state EbN and excited state ＥbE, as well as the electrostatic interaction energy Ｅs which is caused by electron migration from donor to acceptor, have been calculated, respectively. Based on the theory of one-dimensional harmonic vibrator model, the energy valley in the potential energy curve when the excimer is formed has been simplified. Thus the potential energy function and the energy value of the excimer formed by the clusters in the critical distance can be calculated, and then the electron migration electrostatic interaction energy can be gotten too. Accordingly the fluorescence emission mechanism of the broad and featureless fluorescence peak has been explained theoretically.
The third-order nonlinear optical properties of a side-chain conjugated polythiophene film
Authors: Gao Chao  , Xiao Qi  , Qiu Shao-Jun  , Hou Chao-Qi  , Xu Pei-Pei  , Liu Jian-Ｑun  ,   (1)西安近代化学研究所,西安  710065; (2)西安近代化学研究所,西安  710065；中国科学院西安光学精密机械研究所瞬态光学与光子技术国家重点实验室,西安  710119; (3)中国科学院西安光学精密机械研究所瞬态光学与光子技术国家重点实验室,西安  710119
Published: December 2020

A novel side-chain conjugated polythiophene derivative poly［3-（5′-octyl-thienylene-vinyl）-thiophene］ （POTVTh） was synthesized. The polymer films showed a broad absorption band and a narrow bandgap of about 1.82 eV. The third order nonlinear optical properties of the film were measured by Z-scan technique at 800 nm, which showed the nonlinear absoption coefficient, the nonlinear optical refractive index and third order nonlinear optical susceptibility as 5.63×10-7cm/W, -6.38×10-11cm2/W and 4.32×10-9esu, respectively. The results are one to two orders of magnitude larger than those of normal conjugated polymers without conjugated side-chain, indicating the good nonlinear optical properties of the polymer.
Transplantation method of solutions and the solutions of a coupled VCmKdV equation with source
Authors: Yang Jian-Rong  , Mao Jie-Jian  ,   上饶师范学院物理与电子信息系，上饶  334001
Published: December 2020

According to the comparability of the nonlinear terms and dispersion terms between the variable coefficient modified Korteweg-de Vries （VCmKdV） equation and constant coefficient KdV-mKdV equation, we transform properly the KdV-mKdV equation with known solutions, transplant its solutions to the VCmKdV equation with unknown solutions, and thus construct the transplantation relation between the solutions of two different equations. Utilizing this transplantation method of solutions, we obtain new exact solutions and solitary wave-like solutions of the coupled VCmKdV system, which is derived from a two-layer fluid model with source or sink. Then we compare the Bcklund transformation and this transplantation method, and analyse the influence of source and sink on the amplitude.
The spatial degrees of freedom of MIMO quantum channels
Authors: Xiao Hai-Lin  , Ouyang Shan  , Nie Zai-Ping  ,   (1)电子科技大学电子工程学院，成都  610054; (2)电子科技大学电子工程学院，成都  610054；桂林电子科技大学信息与通信学院，桂林  541004; (3)桂林电子科技大学信息与通信学院，桂林  541004
Published: December 2020

Quantum communication is a process of quantum key distribution （QKD）. Current QKD technology restricts communication to a low bit rate. To improve the QKD bit rate and develop high rate and capacity, we propose a multiple-input-multiple-output quantum key distribution system. However, quantum field itself inevitably involves quantum noise （which is determined by the quantum mechanics ）, which restrains the increase of capacity, and limits space resource utilization, that is, the problem of spatial degrees of freedom arises. The quantumization of the photon field and the electromagnetic wave equation satisfying the Schrdinger equation condition are adopted to investigate the upper bound of the spatial degrees of freedom for MIMO quantum channels, which will provide theoretical support and technical basis for developing robust space time processing algorithm for MIMO quantum communication and designing high performance systems.
A family of hyperchaotic systems with four-wing attractors
Authors: Hu Guo-Si  ,   烟台大学光电学院，烟台  264005；同济大学电信学院，上海  201804
Published: December 2020

It is easy to construct a hyperchaotic system，and many systematic approaches，based on Chua system，can be used for generating multi-scroll attractors. However, few reports discuss the smooth Lorenz-like system with multi-wing attractors，and the attractors with both hyperchaotic dynamics and multi-wing topological structure are seldom reported. Based on the existing smooth hyperchaotic system，the common characteristics of these systems are analyzed. A novel coordination transformation method is used for converting all the attractors' topological structure from two-wing to four-wing. Moreover，the hyperchaotic property is preserved in resulting system，the complexity of attractors is enhanced，and they are more suitable to be used in secure encryption communication.
Anti-synchronism of the bidirectional coupled chaotic system
Authors: Liu Fu-Cai  , Zang Xiu-Feng  , Song Jia-Qiu  ,   燕山大学西校区工业计算机控制工程河北省重点实验室，秦皇岛  066004
Published: December 2020

For two linearly bidirectional coupled unified chaotic systems，based on adaptive control technique, the anti-synchronization is completely realised. The adaptive-controller and the coupling coefficient are both estimated by the Lyapunov stable theorem and the minimum value theorem. This method can realise anti-synchronization, not requiring to know the scope of the coupling coefficient and the maximum value of the coupling chaotic systems. We apply this criterion to the case of the coupled Chen-Chen system to test our method，the numerical simulations illustrate that this method has a good performance.
Period-doubling gait and chaotic gait of biped walking model
Authors: Liu Ning  , Li Jun-Feng  , Wang Tian-Shu  ,   清华大学工程力学系，北京  100084
Published: December 2020

Passive walking model can exhibit natural gait on a slope， depending only on the gravity. The gait changes with the changing of parameters. The fixed point of the periodical gait can be obtained by the combination of cell mapping method and Newton-Raphson iteration. By the aid of cell mapping method，periodical cells can be used as the initial value of iteration，and the basins of attraction can be obtained. Simulations of models with different parameters show that the increasing of moment of inertia will result in the appearance of period-doubling and chaotic gaits. The same effect can be obtained by the decreasing of foot radius or position of center of mass.
Study on structural and transport properties of nonstoichiometric La0.67Sr0.33-x□xMnO3
Authors: Xu Gen-Jian  , Tan Wei-Shi  , Cao Hui  , Deng Kai-Ming  , Wu Xiao-Shan  ,   (1)南京大学固体微结构物理国家重点实验室，南京大学物理系，南京  210093; (2)南京理工大学软化学与功能材料教育部重点实验室，南京理工大学理学院应用物理系，南京  210094
Published: December 2020

In this article，hole-doped nonstoichiometric manganites La0.67Sr0.33-x□xMnO3 (x=0，0.05，0.1，0.15，0.2，0.25，0.3，0.33) with A-site vacancy were synthesized using the solid-state reaction technique and the effect of A-site vacancy on structure and transport properties were studied. Results from Rietveld refinement of powder X-ray diffraction patterns showed that all samples were single phase with space group R3c and there were no structural phase transition for vacancy content x ranging from 0 to 0.33. The lattice parameters and volume of unit cell vary distinctly with x. These variations maybe result from the uncertain occupation ratio of vacancies at A-sites and Mn-sites. The bond angle of Mn—O—Mn decreases with increasing x，which indicates the presence of further distortion of MnO6 octahedron. Electrical measurements of La0.67Sr0.33-x□xMnO3 showed that the samples exhibited a metallic-insulator phase transition for xTMI towards higher temperature. In the range of 0.25≤x≤0.33，the samples exhibit insulating behavior without metallic-insulator transition，and also the effect of the magnetic field is to lower the resistivity.
Symmetry breaking crisis of chaotic attractors
Authors: Zhang Ying  , Lei You-Ming  , Fang Tong  ,   (1)西北工业大学理学院，西安  710072; (2)西北工业大学力学与土木建筑学院，西安  710072
Published: December 2020

Most nonlinear dynamic systems may exhibit a certain symmetrical form. Symmetry is a kind of invariance，maybe appearing in different topological forms under different situations，but always keeping the characteristic of symmetry. The transition between different symmetric forms often leads to symmetry breaking bifurcation or crisis. Many studies on symmetry breaking bifurcations of phase trajectories of a nonlinear dynamical system have been reported，most of which are related to periodic or quasi-periodic orbits. Only a few of them ever mentioned that “duality” might also exist for a couple of chaotic attractors in symmetrical nonlinear dynamical systems. Recently，in the study of the saddle-node bifurcation resulting from symmetry breaking of periodic phase orbits in a Duffing oscillator driven by a sinusoidal excitation，an interesting phase portrait of the flow pattern of discrete Poincaré mapping points has been obtained after symmetry breaking bifurcation. Along with the flow pattern，two stable periodic nodes and one periodic saddle，together with its stable and unstable manifolds，are shown，which are all in a regular form yet. In this study, as an extension of the above results，a complicated portrait for attractive basins of coexisting periodic and chaotic attractors in a parametrically driven double-well Duffing system is obtained，which is fractal，interwoven，yet symmetrical. In addition，the neighboring symmetry breaking crises are studied qualitatively.
Multiple light scattering of non-spherical particles with elliptical cross section
Authors: Dai Bing  , Luo Xiang-Dong  , Wang Ya-Wei  ,   (1)江苏大学理学院, 镇江  212013; (2)南通大学理学院, 南通  226007
Published: December 2020

A model for a kind of non-spherical particles with elliptical cross section is established, and their phase functions are obtained. Based on the radiative-transfer equation, considering the shape and size distribution, we obtain the multiple light scattering of this kind of particles. Our results are in agreement with the earlier results in two special cases, which verifies that our method is reliable. The calculation and analysis show that the distribution of multiple scattered intensities of non-spherical particles is flatter than that of the spherical particles. The larger the shape parameter or the size of particles is, the smaller the scattering angle is. The wider the size-distribution or shape-distribution is, the flatter the angular distribution of the light intensity is. The angular distribution of the light intensity becomes flatter with the increasing optical thickness. The multiple scattering intensity at a scattering angle at first increases and then decreases with the increasing optical thickness. A new potential way of studying the multiple light scattering of actual non-spherical particles is provided.
Experimental study on phase vortices of speckles and their propagation properties
Authors: Song Hong-Sheng  , Cheng Chuan-Fu  , Liu Man  , Teng Shu-Yun  , Zhang Ning-Yu  ,   (1)山东师范大学物理与电子科学学院,济南  250014; (2)山东师范大学物理与电子科学学院,济南  250014；山东建筑大学理学院,济南  250101; (3)山东师范大学物理与电子科学学院,济南  250014；山东轻工业学院数理系,济南  250100
Published: December 2020

By recording the interference patterns of the speckle fields and the reference beam with the charge coupled device （CCD）, and by using the digital Fourier transform technique, the amplitude and the phase distribution of the speckle fields are experimentally extracted. We find that at the tangential points of the zero curves of the real and the imaginary parts, a new kind of speckle phase singularities may appear. Different from the conventional singularities at the zero crossings of the real and imaginary parts with the monotonically spiral change of phase, this new kind of singularities has the property that the phase undergoes an increase and then a decrease around the singular point with nearly a symmetric distribution. We introduce the concept of quasi twin phase vortices to explain the formation of the new kind of phase vortices. Based on a theoretical study of the longitudinal autocorrelation function of the speckle intensities, we experimentally observe the propagation of the phase vortices of speckles. It is found that in planes at different propagation distances but within a longitudinal correlation length, the real and the imaginary parts of the complex speckle field vary considerably, but the position of the phase vortices and the angle of the zero crossings of the real and imaginary parts remain unchanged.
Numerical simulation of intracavity second harmonic generation for optically pumped semiconductor vertical-external-cavity surface-emitting lasers
Authors: Zong Nan  , Cui Da-Fu  , Li Cheng-Ming  , Peng Qin-Jun  , Xu Zu-Yan  , Qin Li  , Li Te  , Ning Yong-Qiang  , Yan Chang-Ling  , Wang Li-Jun  ,   (1)中国科学院长春光学精密机械与物理研究所激发态物理重点实验室,长春  130033; (2)中国科学院物理研究所光物理重点实验室,北京  100190; (3)中国科学院物理研究所光物理重点实验室,北京  100190；中国科学院研究生院,北京  100049; (4)中国科学院研究生院,北京  100049；中国科学院长春光学精密机械与物理研究所激发态物理重点实验室,长春  130033
Published: December 2020

A numerical model of intracavity second harmonic generation（SHG） is constructed considering the effect of phase mismatching and birefringent walk-off in nonlinear crystals for optically pumped semiconductor vertical-external-cavity surface-emitting laser（OPS-VECSEL）. The influences of the crystal length and the pump power on the SHG output power for some nonlinear crystals, such as BBO, LBO and PPLN, are studied in detail. The results are in good agreement with the experimental data.
Focusing of an anomalous hollow beam by a spherically aberrated aperture lens and its phase singularities in the focal region
Authors: Luo Ya-Mei  , Lü Bai-Da  ,   (1)四川大学激光物理与化学研究所，成都  610064; (2)四川大学激光物理与化学研究所，成都  610064；泸州医学院生物医学工程系，泸州  646000
Published: December 2020

The focusing properties of a novel type of beam, i.e. an anomalous hollow beam focused by a spherically aberrated aperture lens, are studied by using the Debye formula. It is shown that， the shape of the anomalous hollow beam does not keep unchanged upon propagation. However, the anomalous hollow beam at a certain position can keep its initial profile nearly unchanged by selecting the suitable truncation parameter and spherical aberration. The motion, creation and annihilation of phase singularities occur in the focal region, which depends on the truncation parameter,the spherical aberration and the half angle of the aperture lens. The saddle points may appear, and the annihilation process of a pair of phase singularities is accompanied by the annihilation of a pair of saddle points in the spherical aberration-free case, which leads to the subwavelength structure. The results are illustrated by numerical examples and are compared with the results of previous work.
Analysis of reflection phase for high impedance surface based on a transmission line model
Authors: Li You-Quan  , Fu Yun-Qi  , Zhang Hui  , Yuan Nai-Chang  ,   国防科学技术大学电子科学与工程学院,长沙  410073
Published: December 2020

A transmission line model capable of predicting the reflection phase of high impedance surfaces in normal incident is proposed. The surface impedance of high impedance surface （HIS） can be regarded as the effective capacitive impedance of patch array in parallel with the inductive impedance of substrate layer, and the effect of vias conductor can be ignored at normal incidence. Results of the a nalytical model agree well with the HFSS simulated results. HIS with different parameters are fabricated and tested, the reflection phase of HIS predicted using the transmission line model agree well with the measured results, which proves the validity of this transmission line model.
A novel filter with low angle effect
Authors: Xue Hui  , Zheng Zheng-Rong  , Gu Pei-Fu  , Zhang Jin-Long  , Shen Wei-Dong  , Chen Hai-Xing  ,   (1)杭州科汀光学技术有限公司,杭州  311100; (2)浙江大学现代光学仪器国家重点实验室,杭州  310027
Published: December 2020

The filters with low angle effect are composed of high index dielectric layers and metallic layers laid alternately. When used in the case of oblique incidence or large cone angle incidence, this filter reduces shift of central wavelength significantly while still maintaining its filter characteristics. Theoretical and experimental studies show that such a novel filter can be used in the situation of both large incident angle and cone angle.This effect is due to the usage of high index material and its induced transmittance.
Numerical calculation of parameters of freak wave and its dispersion relation
Authors: Xie Tao  , Nan Cheng-Feng  , Kuang Hai-Lan  , Zou Guang-Hui  , Chen Wei  ,   武汉理工大学信息工程学院,武汉  430070
Published: December 2020

A numerical method for extracting parameters of extreme sea wave and calculating its dispersion relation is presented. The nonlinear sea surface can be regarded as waves whose wave numbers and frequencies change with temporal and spatial points. At every point, the height of sea surface can be interpolated by the value of an extending sine wave whose parameters （such as wave numbers and frequencies） are constant. From the first order and the second order derivative of extreme wave, we can extract wave numbers, frequencies, and amplitudes of the extreme wave. The numerical amplitude results show that this method is valid. Comparing values of ω2/k with g, we can find that the nonlinear area does not lie in the area of extreme waves, but lies very closely to both sides of them. The corresponding wave heights in these areas are lower than that in the linear dispersion area. Compared with wavelet and Hilbert transform analysis method, our method has two advantages: Firstly, it saves much buffer capacity and CPU time. Secondly, it can supply disperse relationship of systems which other methods cannot supply. The disadvantage of this method is that, in the area of engineering application, it is only applicable to systems with coexisting temporal series data and spatial data.
A model considering the ionizing radiation effects in MOS structure
Authors: Chen Wei-Hua  , Du Lei  , Zhuang Yi-Qi  , Bao Jun-Lin  , He Liang  , Zhang Tian-Fu  , Zhang Xue  ,   (1)西安电子科技大学技术物理学院，西安  710071; (2)西安电子科技大学微电子学院，西安  710071
Published: December 2020

Based on the physical process of holes trapped in oxide and interface trap buildup induced by proton, a unified physics-based model of oxide-trapped charge and interface trap charge in MOSFET after ionizing radiation exposure as a function of radiation dose is proposed. This model predicts that the oxide-trapped charge density and interface trap charge density induced by radiation rays would be linear in dose at low dose levelss, and would deviate from linear relationship and tend to saturation at moderate to high dose levels. The change of these two kinds of charge induced by ionizing radiation as a function of radiation dose can be well described by the expressions proposed in this model. At last, the correlation between these two kinds of charge is discussed and a linear dependence is suggested at low dose level. This model gives insights into the trap generation in gate oxide induced by radiation, and provides a more accurate predictive model for radiation damage in MOS devices operated in space ionizing radiation environment.
Ab initio simulation on thermodynamic equation of state of fcc aluminum under high temperature and pressure
Authors: Ji Guang-Fu  , Zhang Yan-Li  , Cui Hong-Lingi  , Li Xiao-Feng  , Zhao Feng  , Meng Chuan-Min  , Song Zhen-Fei  ,   (1)中国工程物理研究院流体物理研究所冲击波物理与爆轰物理国防科技重点实验室，绵阳  621900; (2)中国工程物理研究院流体物理研究所冲击波物理与爆轰物理国防科技重点实验室，绵阳  621900；四川大学物理科学与技术学院，成都  610064; (3)中国工程物理研究院流体物理研究所冲击波物理与爆轰物理国防科技重点实验室，绵阳  621900；西南交通大学高温高压物理研究所，成都  610031
Published: December 2020

The ab initio electronic structure optimization and total-energy calculations are used to study the equation of state （EOS） and elastic properties of fcc aluminum at zero temperature. We use the calculated energy of a solid as a function of the molecular volume fitting to the quasi-harmonic Debye model to obtain the non-equilibrium Gibbs function, then to derive the thermal equation of state （EOS） of the corresponding phase. The melting curve at different pressures is presented based on the Burakovsky-Preston-Silbar （BPS） model. All total-energy calculations are based on the average of local density approximation （LDA） and general gradient approximation （GGA）. The results show that the calculated EOS and pressure dependence of thermodynamics and melting curve are in good agreement with the shock compression and the diamond-anvil-cell （DAC） data within a wide range of pressure up to 225 GPa.
First-principles calculation of CdS electronic structure doped with Mg and Cu
Authors: Dang Sui-Hu  , Li Chun-Xia  , Han Pei-De  ,   (1)长江师范学院物理学与电子工程学院，重庆  408003; (2)太原理工大学材料科学与工程学院，太原  030024
Published: December 2020

The geometry structure, band structure, partial density of states, mulliken changes, and electron density of zinc blende CdS and CdS:M（M=Mg, Cu） were studied systemically by the density functional theory（DFT） based on first-principles pseudopotential caculation. It is shown that the M-doped material has a smaller lattice constant, which results in a local lattice distortion. The band structure and density of states（DOS） were further calculated and analysed in detail. The results show that Cds doped with Mg, Cu can provid many states of holes. The p-type conduction was obtained. And Cu was a better p-type dopant than Mg.
Study on the process of collision between a polaron and a triplet exciton in conjugated polymers
Authors: Sun Zhen  , An Zhong  , Li Yuan  , Liu Wen  , Liu De-Sheng  , Xie Shi-Jie  ,   (1)河北师范大学物理科学与信息工程学院，石家庄  050016; (2)山东大学物理学院，晶体材料国家重点实验室，济南  250100; (3)山东大学物理学院，晶体材料国家重点实验室，济南  250100；山东济宁学院物理系，曲阜  273155
Published: December 2020

Adopting a tight-binding electron-phonon interacting model, we investigated the collision between a negative polaron and a triplet exciton in polymers under the influence of different electric fields. The results show that, after the collision, the electrons of the system have the most probability of keeping the same configuration as it initially is. The electron confined in the polaron defect has some probabilities to be excited into the conduction band to form a free carrier， and the triplet exciton has some, even less, probabilities to be annihilated by the negative polaron to form an excited polaron in the collision. It is also found that the collision proccess can influence the stability of the polaron and there are new energy levels appearing in the gap after the collision. Because an excited polaron can decay radiatively to its ground state, the scattering process has influence on the efficiency of electroluminescence. These results will help us to understand the properties of polaron transport and electroluminescence in polymers.
Quantum transport of multi-terminal coupled-quantum-dot-molecular bridge
Authors: Yin Yong-Qi  , Li Hua  , Ma Jia-Ning  , He Ze-Long  , Wang Xuan-Zhang  ,   (1)哈尔滨师范大学物理与电子工程学院，哈尔滨  150025; (2)哈尔滨师范大学物理与电子工程学院，哈尔滨  150025；黑龙江省先进功能材料与激发态重点实验室，哈尔滨  150025; (3)黑龙江工程学院电子工程系，哈尔滨  150050
Published: December 2020

The characteristics of quantum transport through a four-terminal coupled-quantum-dot-molecular bridge are investigated theoretically by nonequilibrium Green’s function. The transmission probabilities of the electrons transported through the molecular bridge to every terminal are obtained.
Universal scaling relations of the Hall resistivity and Hall angle near the vortex glass transition and the unified Hall resistivity equation
Authors: He Li  , Hu Xiang  , Yin Lan  , Xu Heng-Yi  , Xu Xiao-Lin  , Guo Jian-Dong  , Li Chuan-Yi  , Yin Dao-Le  ,   北京大学物理学院人工微结构和介观物理国家重点实验室，北京  100871
Published: December 2020

Universal scaling relations of the pinning effect on the Hall resistivity ρxy and Hall angle θH were shown. Considering the extended power law form of ρxx and the microscopic analysis of σxy，we derive unified ρxy equations for superconductors with and without double sign reversal.
Study of Ag/ZnO composite material by universal power law
Authors: Yin Gui-Lai  , Li Jian-Ying  , Li Sheng-Tao  ,   西安交通大学电力设备电气绝缘国家重点实验室，西安  710049
Published: December 2020

The dielectric properties of Ag/ZnO composite material are investigated and a strong low-frequency dispersion phenomenon is found. The experimental results are systematically studied in the frequency range of 0.1—107 Hz and in the temperature range of 173—473 K. By means of normalization of conductivity, it is found that samples with different Ag contents show similar mechanism of dielectric loss, which is suggested as electron jumping between deep levels. In addition, it is also found that the dependence of E1mA on Ag content is similar to that of αlf on Ag content, which is a novel result in the research of varistor materials. The results can be fully understood by means of universal power law.
ASE effect in pulsed energy-storage rep-rated Yb:YAG disk laser amplifier
Authors: Yan Xiong-Wei  , Yu Hai-Wu  , Cao Ding-Xiang  , Li Ming-Zhong  , Jiang Dong-Bin  , Jiang Xin-Ying  , Duan Wen-Tao  , Xu Mei-Jian  ,   中国工程物理研究院激光聚变研究中心,绵阳  621900
Published: December 2020

Based on the energy-level structure of quasi-three-level Yb ion, an amplified spontaneous emission（ASE） model in pumping process is set up. The stored energy density distribution and the energy that can be extracted in Yb:YAG crystal are calculated. The effect of ASE on energy-storage is investigated specifically, which includes the aperture, doping concentration and thickness, and working temperature of the gain medium. This paper gives an optimizing design of a pulsed energy-storage rep-rated Yb:YAG disk laser amplifier, which will be helpful in designing high-energy diode-pumped solid-state lasers based on Yb-doped materials.
Fabrication of transparent conductive AZO （ZnO:Al） film by plasma enhanced chemical vapor deposition
Authors: Chen Zhao-Quan  , Liu Ming-Hai  , Liu Yu-Ping  , Chen Wei  , Luo Zhi-Qing  , Hu Xi-Wei  ,   华中科技大学电气与电子工程学院，核聚变与电磁新技术教育部重点实验室，武汉  430074
Published: December 2020

AZO（ZnO:Al） polycrystalline thin films with strong adhesion to the substrate, as low as 89 Ω of sheet electronic resistivity and as high as 79% of visible light transmittance,are fabricated by PECVD （plasma enhanced chemical vapor deposition） method on glass and silicon substrate. The AZO film fabricated by PECVD is a useful attempt. The AZO transparent conductive film has the good photovoltaic properties like that of ITO （In2O3: Sn）; moreover, it is cheap, more nontoxic, and more stable in hydrogen plasma environment than ITO. The results obtained are very important to the selection of the technical conditions.
Correlation between the usage degree of the synonymous codon and the strength of combination based on the quasi-amino acid coding
Authors: Zhu Ping  , Gao Lei  , Xu Zhen-Yuan  ,   (1)江南大学理学院,无锡  214122; (2)江南大学理学院,无锡  214122；江南大学信息工程学院,无锡  214122
Published: December 2020

The relative usage degree of the synonymous codon is computed and the use of preferences of the synonymous codon in 78 human genes（19967 codons） is analysed based on the quasi-amino acids coding. The results of Shi Xiufan et al. show that human genes clearly show the consistent preference in synonymous codon choice in all codon family based on the genomic genetic codes. That is, human genes prefer to use the codons with strong combination of the codon-anticodon， the codons ending with c, so that the use of the codons with moderate combination is avoided. The choice of codon in human genes is not only affected by the isochore and genome in the genome structure， but also related to the strength of combination with the codon-anticodon. All the above-mentioned factors affect the human genes，and so all the codon families clearly show the consistent preference to the synonymous codon. This study shows that the above-mentioned characteritics are more obvious when the method of quasi-amino acids coding is used.
Amplification of hybrid-widen linewidth of broadband pulses in Nd:glass laser systems
Authors: Liu Lan-Qin  , Mo Lei  , Luo Bin  , Su Jing-Qin  , Wang Wen-Yi  , Wang Fang  , Jing Feng  , Wei Xiao-Feng  ,   (1)西南交通大学计算机与通信工程学院，成都  610031; (2)中国工程物理研究院激光聚变研究中心，绵阳  621900
Published: December 2020

Base on physical amplification models established to describe the broadband laser pulse amplification processes, using numerical simulation methods, we analyse the amplification abilities of the Nd:glass laser system under different spectral linewidths. The results indicate that the output energies decrease with the increasing spectral linewidth. Compared with narrowband laser pulse of 3000 J/1ns, under the same conditions, the output energies of broadband laser pulse will reduce 2%, 11% and 27% for 2nm, 5nm and 10nm laser pulses,respectively. The influences of cross relaxation on the amplification processes are also studied. The output energies of completely nonhomogeneous broadening will reduce about 20% compared with that of completely homogeneous broadening. Then, the range of cross relaxation time is estimated to be 0—10 ns.
Simulation of the diurnal variation of the tropical convection
Authors: Ping Fan  , Luo Zhe-Xian  ,   (1)南京信息工程大学气象灾害省部共建教育部重点实验室，南京  210044; (2)南京信息工程大学气象灾害省部共建教育部重点实验室，南京  210044；中国科学院大气物理研究所云降水物理与强风暴实验室，北京  100029
Published: December 2020

The diurnal variation of the tropical convection is investigated using hourly outputs from a two-dimensional cloud-resolving model simulation. The features of cloud microphysics in tropical convections are proposed by the contrastive analysis of the simulation. The model is forced by the observational data obtained from tropical ocean global atmosphere coupled ocean-atmosphere response experiment as the initial and boundary fields. The diurnal composites are carried out in weak diurnal SST variations （case W） and strong diurnal SST signals （case S） according to the amplitude of diurnal SST variations. The simulation results show that the ice water path in case W is larger than the liquid water path in case S, and more water cloud and less ice cloud exist in case W than in case S. The results also show that the surface rain rates reach their peaks in the early afternoon in case S, while the surface rain rates reach their peaks in the night in case W. Further comparison of cloud microphysics budgets shows that the coagulation of precipitation ice （sum of snow and graupel） is less than the coagulation of liquid water （sum of cloud water and precipitation water） and ice cloud can be formed in case W.
Influence of deposition parameter on chemical structure and moisture resistant properties for SiNx films deposited by DC pulse magnetron sputtering
Authors: Ding Wan-Yu  , Wang Hua-Lin  , Miao Zhuang  , Zhang Jun-Ji  , Chai Wei-Ping  ,   (1)光电材料与器件研究所，大连交通大学，大连  116028；材料科学与工程学院，大连交通大学，大连  116028; (2)国家包装产品质量监督检验中心，大连  116028
Published: December 2020

Hydrogen-free SiNx films were deposited by direct current pulse magnetron sputtering at room temperature. We have studied the influence of N2 flow rate and Si target sputtering power on the structural characteristics and properties of deposited films by using Fourier-transform infrared spectroscopy，auto water vapor permeability tester，ultraviolet-visible spectrophotometer，stylus profilometer，and contact angle measurement. The results indicate that the content of Si—O bonding in SiNx films increaseds and moisture resistant property of SiNx films decreases with increasing N2 flow rate or decreasing Si target sputtering power. The films deposited at 300W of Si sputtering power and 6sccm of N2 flow rate show excellent water vapor permeability (0.764) with transmittance higher than 97.5% in visible range.