bluuebunny/crossref_metadata_2025 huggingface dataset:
Excitons and effects of phonons on excitons in asymmetric square quantum well
Authors: Deng Yan-Ping  , Lü Bin-Bin  , Tian Qiang  ,   Department of Physics, Beijing Normal University, Beijing 100875, China
Published: December 2020

By LLP(Lee-Low-Pines)-like transformation and fractional-dimension variational treatment, the ground-state energies of excitons confined in Ga1－xAlxAs/GaAs/Ga0.7Al0.3As asymmetric square quantum well and the influence of phonons are demonstrated. The exciton ground-state energy has a minimum value with the increasing well width. And we make clear the effects of the barrier height on the fractional dimension, exciton ground energy and binding energy. After taking into account of the interaction of exciton with LO-phonons, the values of the exciton ground-state energies increase remarkablely. Moreover, the exciton binding energy increases as the asymmetric well-width decreases or the barrier height increases.
Theoretical study on the hopping conductivity of quasi-one-dimensional disordered systems
Authors: Ma Song-Shan  , Xu Hui  , Guo Rui  , Cui Mai-Ling  ,   College of Physical Science and Technology, Central South University, Changsha 410083, China
Published: December 2020

Based on a tight-binding disordered model describing a single electron band, a model of quasi-one-dimensional disordered systems with several chainsis established, and the direct current (dc) and alternating current (ac) conductance formula are obtained. By calculation, the dependence of the dc and ac conductivity on the disorder mode, dimension, temperature, and electric field is studied. The results indicate that the dc and ac conductivity of the systems decreases with the increase of the degree of lattices energy disorder, while the off-diagonal disorder can enhance the electrical conductivity of the system. Meanwhile, the conductivity increases with the increase of the number of chains in the systems. The model also quantitatively explains the temperature and electric field dependence of the conductivity of the system, that is, in diagonal disordered systems, the ac conductivity of the systems increases with the increasing of temperature, in off-diagonal disordered systems, the ac conductivity of the systems decreases with the increasing of temperature, while the dc conductivity of the systems in all disordered modes increases with the increasing of temperature. In addition, the dc conductivity of the quasi-one-dimensional disordered systems increases with the increasing of the strength of dc electric field, showing the non-Ohm’s law conductivity characteristics, and the larger the number of chains in systemis, the more slowly the dc conductivity of systems increases with the increasing electric field. The ac conductivity quasi-one-dimensional disordered systems increases as the frequency of the external electric field rises, satisfying the relation σac(ω)∝ω2[In(1/ω)]2.
Luminous performance improvement of InGaN/GaN light-emitting diodes by modulating In content in well layers
Authors: Zhu Li-Hong  , Cai Jia-Fa  , Li Xiao-Ying  , Deng Biao  , Liu Bao-Lin  ,   Department of Physics, Xiamen University, Xiamen 361005, China
Published: December 2020

InGaN/GaN triangular shaped multiple quantum wells (MQWs) grown on sapphire substrate were adopted as an active layer of light-emitting diodes (LEDs) by modulating In content in well layers. The temperature dependence of the normalized integrated photoluminescence (PL) intensity showed that the overlap of the electron and hole wave-functions of the LEDs with triangular shaped MQW is much higher than that of the LEDs with conventional rectangular MQW structures, which improves the internal quantum efficiency (IQE) to a certain degree. On the other hand, it was found that the blue shift of the peak energy as a function of injection current is improved for the device with triangular shaped MQW structure from the electroluminescence (EL) spectra of the two series devices. The comparison above indicates that the triangular MQW LEDs are more efficient and more stable.
Analysis of failure mechanism of GaN-based white light-emitting diode
Authors: Xue Zheng-Qun  , Huang Sheng-Rong  , Zhang Bao-Ping  , Chen Chao  ,   (1)Department of Physics, Xiamen University, Xiamen 361005, China; (2)Department of Physics, Xiamen University, Xiamen 361005, China; Center for Semiconductor Lighting of Fujian Province, Xiamen 361005, China; (3)San An Electronics Corporation, Xiamen 361005, China
Published: December 2020

Accelerated aging and life-time tests at ambient temperatures of 40 ℃,70 ℃ and room temperature were carried out on GaN-based white light-emitting diodes (LEDs). The electrical, optical and thermal characteristics of the device were compared before and after different aging times in order to investigate the failure mechanism of the device. Here, we mainly analyzed the failure mechanism related with the chip and the phosphor of the LED. The current-voltage characteristics demonstrated that both the series resistance and the tunnel current increase under lower forward voltages after aging, which were due to the degradation of p-type ohmic contact and the increase of defect density. The thermal characteristics confirmed that the thermal resistance increased rapidly under high aging temperature. This was mainly attributed to the fracture of different materials inside the devices caused by the difference in thermal expansion coefficients. Optical measurements indicated that high aging temperature could accelerate the degradation of output power and reduce the conversion efficiency of the phosphor as well. Finally, the life time of the device was calculated using Arrhenius-equation, and the failure mechanism was analyzed.
Fabrication and performance of indium oxide based transparent thin film transistors
Authors: Xu Tian-Ning  , Wu Hui-Zhen  , Zhang Ying-Ying  , Wang Xiong  , Zhu Xia-Ming  , Yuan Zi-Jian  ,   (1)State Key Laboratory for Modern Optical Instruments, Department of Physics, Zhejiang University, Hangzhou 310027, China; (2)State Key Laboratory for Modern Optical Instruments, Department of Physics, Zhejiang University, Hangzhou 310027, China; Department of Science, Zhijiang College of Zhejiang University of Technology, Hangzhou 310024, China
Published: December 2020

Indium oxide thin film was deposited on glass substrate by radio frequency magnetron sputtering at room temperature. The In2O3 film was polycrystalline with a preferred (111) orientation and a grain size of 33 nm was estimated. The bottom-gate staggered thin film transistors (TFTs) were fabricated by standard photolithography, with In2O3 as active channel layers. The In2O3 TFTs exhibit good gate bias controlling characteristic with a field effect mobility of 6.3 cm2/V·s, an on-off current ratio of 3×103, and a threshold voltage of -0.9 V. Device performance and room temperature fabrication technology make In2O3 TFTs promising for display panel applications.
Optical properties of GaMnN films grown by metal-organic chemical vapor deposition
Authors: Xing Hai-Ying  , Fan Guang-Han  , Yang Xue-Lin  , Zhang Guo-Yi  ,   (1)北京大学宽禁带半导体研究中心,北京  100871; (2)华南师范大学光电子材料与技术研究所，广州  510631; (3)天津工业大学信息与通信工程学院，天津  300160；华南师范大学光电子材料与技术研究所，广州  510631
Published: December 2020

Optical absorption spectra for a series of GaMnN samples with different Mn content grown by metal-organic chemical vapor deposition have been investigated. Compared with GaN, the absorption coefficient of Ga1-xMnxN increases in the UV region and an absorption peak can be observed near 144 eV. In addition, the absorption coefficient increases with the increase of the Mn content. The experimental results are in excellent agreement with theoretical data based on density functional theory. Associated with theoretical data, the absorption peak near 144 eV is assigned to 5T2→5E internal transition between the e state and the t2 state of Mn3+ ion.
Raman scattering study of the spin ladder compound Sr14Cu24O41+δ
Authors: Cheng Li  , Xiong Rui  , Shi Jing  ,   (1)Key Laboratory of Acoustic and Photonic Material and Device of Ministry of Education, School of Physics and Technology, Wuhan University, Wuhan 430072, China; (2)Key Laboratory of Acoustic and Photonic Material and Device of Ministry of Education, School of Physics and Technology, Wuhan University, Wuhan 430072, China; International Center for Material Physics, Shenyang 110016, China
Published: December 2020

The spin ladder compounds Sr14Cu24O41+δ were synthesized by conventional solid state reaction method with subsequent annealing at 400, 500, 600, 800 and 900 ℃, respectively. The energy dispersive spectroscope (EDS) measurement confirms that the content of oxygen in the samples decreases with the increasing of annealing temperature. The measurement of magnetic susceptibility reveals that the sample annealing at 600 ℃ has the largest number of dimers. The measurement of Raman spectrum shows some new Raman vibrational features. Corresponding to δ>0 or δα=cl/cc is near the minimal value 10/7 and the Cu—O bond has relatively long length.
Sub-wavelength beam lasers with surface plasmon structures
Authors: Song Guo-Feng  , Wang Wei-Min  , Cai Li-Kang  , Guo Bao-Shan  , Wang Qing  , Xu Yun  , Wei Xin  , Liu Yun-Tao  ,   Nano-Optoelectronics Laboratory, Institute of Semiconductor, Chinese Academy of Sciences, Beijing 100083, China
Published: December 2020

The simulation of a plasmonic very-small-aperture laser is demonstrated in this paper. It is an integration of the surface plasmon structure and very-small-aperture laser (VSAL). The numerical results demonstrate that the transmission field can be confined to a spot with subwavelength width in the far field (3.5 μm far from the emitting surface), and the output power density can be enhanced over 30 times of the normal VSAL. Such a device can be useful in the application of a high resolution far-field scanning optical microscope.
Polarization dependent phase grating based on two-dimensional structured thin films
Authors: Li Yi-Yu  , Wang Yuan-Yuan  , Chen Hao  , Zhu De-Xi  , Hu Chuan  , Qu Jia  ,   Key Laboratory of Vision Science Research, Ministry of Health of China, School of Optometry and Ophthalmology, Wenzhou Medical College, Wenzhou 325027, China
Published: December 2020

The new phase grating based on two-dimensional structured thin films is reported. The rigorous coupled-wave analysis (RCWA) is employed to calculate the diffraction efficiency which varies with incident wavelength and angle. According to the result obtained by using RCWA, when the wavelength ranges from 600 to 640 nm, TE mode and TM mode can be diffracted in the transmitted 0th and ±1st orders, respectively, at normal incident angle. For example, at the wavelength of 633 nm, the polarization extinction ratio of 0th order is I0,TE/I0,TM=109.8, and the polarization extinction ratio of ±1st order is I±1,TM/I±1,TE =334.6. This polarizing beam splitting phenomenon is confirmed by theoretical simulation with finite-difference time-domain method, which shows that TE mode and TM mode can be separated by an angle of about 10°in glass substrate. The same simulation method is performed for the diffraction at incident angle of 23° in order to compare with the results from RCWA and grating equation calculation.
Laser induced rear-surface-crack damage properties of fused silica etched with HF solution
Authors: Wang Feng-Rui  , Huang Jin  , Liu Hong-Jie  , Zhou Xin-Da  , Jiang Xiao-Dong  , Wu Wei-Dong  , Zheng Wan-Guo  ,   Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900, China
Published: December 2020

The micro subsurface cracks of fused silica etched with HF solution were recorded using atomic force microscope (AFM) and optical microscope. The damage characteristics of cracks with different structures were studied. Experimental results show that after HF etching, the cracks cross section turns into cosine pattern, and its laser induced damage threshold (LIDT) is not determined by the individual breadth or depth parameters, but by the breadth depth ratio of the crack cross section. The curve of LIDT versus the cracks breadth depth ratio was experimentally obtained. Finite difference time domain algorithm was used to calculate the electric field intensity distribution in the vicinity of a crack with cosine cross section, and the theoretical results agree well with the experimental ones.
Effect of Nb on electronic structure of NiTi intermetallic compound: A first-principles study
Authors: Wu Hong-Li  , Zhao Xin-Qing  , Gong Sheng-Kai  ,   北京航空航天大学材料科学与工程学院，北京  100191
Published: December 2020

The electronic structure of pure and Nb doped B2 NiTi have been calculated with the first-principle ultrasoft pseudopotential approach of the plane wave based on the density functional theory aiming at examining the effect of Nb on the electronic structure and bonding characteristic of NiTi. The point defect formation energy calculation results show that the introduction of Nb largely enhances the energy required to form the vacancies and anti-sites of both Ni and Ti sublattice. Furthermore, the calculation results on the partial density of states (PDOS) suggest that the addition of Nb increase the s-s, p-p and d-d electronic interactions between Nb and neighboring Ni and Ti atoms. The electron density of NiTi was also increased with the introduction of Nb. All these Nb-inuced results on electronic structure and bonding characteristic may hamper the hop of Ni and Ti atoms, which may facilitate to improve of oxidation resistance of NiTi intermetallic compound in the experimental findings.
A first-principles study of electronic structure, magnetism, response to pressure and tetragonal distortions of Ni2MnSi Heusler alloy
Authors: Luo Li-Jin  , Zhong Chong-Gui  , Jiang Xue-Fan  , Fang Jing-Huai  , Jiang Qing  ,   (1)常熟理工学院江苏省新型功能材料重点建设实验室，常熟  215500; (2)南通大学理学院，南通  226007; (3)苏州大学物理学院，苏州  215006
Published: December 2020

Crystal structure，magnetism，electronic structure，response to pressure and tetragonal distortions of stoichiometric Ni2MnSi were calculated by first-principles method based on the density functional theory within the projected augmented wave（PAW） appreach. The calculations show the contribution of the spin magnetic moments of Mn atom to the total moments is largest for Ni2MnSi. The low energy part of the total DOS is decided by Si-s-projected DOS, however, the high energy part of the total DOS is decided by the Ni -d-projected DOS, Mn -d-projected DOS and Si -p-projected DOS for Ni2MnSi. The entire energy surface for 095c/a2MnSi，which has significant implications for the growth and properties of thin films. We predict that the Ni2MnSi may also grow single crystal tetragonal structured thin film of ferromagnetic phase with high Curie temperature.
Study on the electronic structure and optical properties of B-doped single-walled carbon nanotubes for formaldehyde adsorption
Authors: Zhang Li-Juan  , Hu Hui-Fang  , Wang Zhi-Yong  , Wei Yan  , Jia Jin-Feng  ,   湖南大学物理与微电子科学学院，长沙  410082
Published: December 2020

The binding energy, electronic structures, optical absorption and reflection spectra of the formaldehyde (HCHO) adsorption on B-doped single-walled (8,0) carbon nanotubes have been investigated using density functional theory based on first principles. The calculated results show that the B-doped SWCNT is sensitive to HCHO, the binding energy increases, peaks in absorption and reflection spectra increase, the peak height decreases and shows blue shift in the lower energy region, and there appears a distinct peak in HCHO adsorption on B-doped carbon nanotubes at the energy of E=172 eV. The results have been discussed theoretically. B-doped single-walled carbon nanotubes are expected to be used to design sensors and photoelectric device for monitoring formaldehyde.
Localization in the one-dimensional systems with long-range correlated disorder
Authors: Zhao Yi  ,   中国工程物理研究院研究生部，北京  100088
Published: December 2020

In this paper, we investigate the localization in a tight-binding one-dimensional model with long-range correlated disorder, which was proposed by de Moura and Lyra. The diagonal on-site energies are distributed in ［-W/2，W/2］ and the Fourier transform S(k) of the two-point correlation function 〈εiεj〉 satisfies S(k)∝k-α with α>0. Using the participation ratio, we confirm that there is a finite range of extended eigenstates for α>2 and Wα<2.
Electronic conductance of zigzag single wall carbon nanotube with an implanted Li atom
Authors: Wang Li-Guang  , Zhang Hong-Yu  , Wang Chang  , Terence K. S. W.  ,   (1)黑龙江八一农垦大学理学院，大庆  163319; (2)江南大学理学院，无锡  214122; (3)新加坡南洋理工大学电气与电子工程学院，新加坡  636798
Published: December 2020

The first principles based on the density functional theory and the nonequilibrium Green's function method are adopted to research the electronic transmission of a zigzag single wall carbon tube with an implanted Li atom. The transmission model is built after optimizing the structure of the single wall carbon nano tube with the implanted Li atom. The electronic transmission and the density of states are obtained. The electronic transmission characteristics are analyzed when the electronic energy and the bias voltage vary. It is found that the conductivity changes obviously as SWCNT is implanted with the Li atom, the electronic transmission band is broadened and the quantum step effect is recovered.
Fabrication and spectral reflective properties of In2O3/SnO2 film
Authors: Tian Qi-Xiang  , Liu Sheng-Chao  ,   (1)解放军理工大学，南京  210007；总装工程兵科研一所，无锡  214035; (2)上海炬通实业有限公司，上海
Published: December 2020

In this paper, In2O3/SnO2 thin films deposited on the fabric for camouflage net are developed. Effect of the film thickness on the spectral reflective properties is investigated thoroughly. Results of the influence of the film thickness on the morphology and spectral properties are presented. Application of In2O3/SnO2 film in the infrared camouflage field is proposed.
Piezoelectric discharge characteristic of ZnO nanorod studied with atomic force microscopy
Authors: Shao Zheng-Zheng  , Wang Xiao-Feng  , Zhang Xue-Ao  , Chang Sheng-Li  ,   国防科技大学理学院物质与材料科学实验中心，长沙  410073
Published: December 2020

Piezoelectric discharge characteristic of semiconductor ZnO nanorod was studied with atomic force microscope in contact mode. The c-axial orientation ZnO nanorod array film was fabricated with two-step wet-chemical method. Electric pulses were got when Pt coated probe contact-scans the ZnO nanorod, their peak value reaches 120 pA. The electric pulse is related with the topography of ZnO nanorod and has a time duration of 30 ms. The contact of Pt coated probe and ZnO nanorod behaves as a Schottky diode. The I-V curve showed the piezoelectric voltage must be larger than 03 V to drive Schottky diode. The resistance of Schottky contact has a magnitude of GΩ order during piezoelectric discharge, which is the major factor impacting the output of piezoelectric potential.
Characteristics of a SiC SBD with semi-superjunction structure
Authors: Yang Yin-Tang  , Geng Zhen-Hai  , Duan Bao-Xing  , Jia Hu-Jun  , Yu Cen  , Ren Li-Li  ,   西安电子科技大学微电子学院，宽禁带半导体材料与器件重点实验室，西安  710071
Published: December 2020

A novel SiC semi-superjunction-Schottky Barrier Diode (Semi-SJ-SBD) structure is proposed, which is the combination of super-junction (SJ) structure and conventional drift region structure. The proposed structure can significantly reduce the specific on-resistance (Ron-sp) and improve the forward characteristics. The breakdown voltage (VB) and specific on-resistance (Ron-sp) in different SJ depth and width are studied using two-dimensional simulator Medici and compared with conventional SiC SBD. The results show that Ron-sp is greatly reduced (greater than 10%) with VB unchanged (less than 4%) when the SJ width is chosen as 2—3 μm and SJ depth is deeper than 5 μm.
Analysis and modeling of quasi-saturation effect in high-voltage LDMOS transistors
Authors: Wang Lei  , Steve Yang  ,   (1)上海宏力半导体制造有限公司，上海  201203; (2)中国科学院上海微系统与信息技术研究所，上海  200050；中国科学院研究生院，北京  100049；上海宏力半导体制造有限公司，上海  201203
Published: December 2020

This paper investigates a specific current saturation phenomenon in high-voltage LDMOS (lateral double-diffused MOS) transistors, i.e., the quasi-saturation effect. By means of simulation tool TCAD, we clarified that the physical mechanism of quasi-saturation effect is the carrier velocity saturation in the drift region. Further more, with the concept of intrinsic drain voltage Vk, a mathematical model is derived to describe the current saturation effect in LDMOS transistors. The proposed model has been primarily validated by Matlab program and exhibites excellent accuracy, speed and scalability. This model can be further implemented in SPICE circuit simulation.
Research on the YBCO/PAN hybridized film and its superconductivity
Authors: Gao Peng-Ju  , Zhang Wen-Gong  , Chen Shu-Qing  , Zhou Xiu-Hua  , Xiao Li-Zu  ,   福建师范大学化学与材料学院高分子研究所，福州 350007
Published: December 2020

A new and simple method of preparing the flexible YBCO/Polyacrylonitrile (PAN) thick film which is not dependent on substrate structure is reported. It is found that, when the PAN content increases from zero to 10wt%, the superconducting critical temperature (Tc) of all the YBCO/PAN specimens lies in the 900—920 K interval, and the specimens show good superconductivity. Moreover, when the PAN content is up to 10wt%, the YBCO/PAN hybridized film shows a certain degree of flexibility. The thickness of the film is about 35μm, and the critical current density (Jc) of the film is 29×104Acm-2 at (1 T, 10 K) and 46×103Acm-2 at (1 T, 40 K). The YBCO/PAN hybridized film, prepared without being treated at high temperature, is hopeful for application in electronics field.
Optical bistability in graded granular composites
Authors: Wu Ya-Min  , Chen Guo-Qing  ,   江南大学理学院，无锡  214122
Published: December 2020

We studied the intrinsic optical bistability(OB) of coated spherical particles with graded dielectric profiles.According to Maxwell equations, we obtained the spatial average of the local field in the core as a function of the external applied field. Numerical results for power-law graded profiles show that the optical bistable behavior is dependent on the shell thickness and the power-laws exponent k. The interval of optical bistability increases with increasing shell thickness or increasing k. In addition, the field-dependent reflectance at normal incidence R in random composites is also investigated, and a hysteretic loop is observed.
Propagation and interaction property of solitary waves in a solid layer with energy influx
Authors: Mandafu  , Naranmandula  ,   内蒙古民族大学物理与电子信息学院，通辽  028043
Published: December 2020

First, the relationships between the amplification or the attenuation of solitary waves and the initial amplitude of solitary waves as well as the structure parameters of the media are determined by direct perturbation method. Second, the solitary wave propagation in a microstructured solid layer is solved numerically using a four-order difference scheme constructed by linearization technique, and also the interaction of the solitary waves with different amplitudes are simulated. As a result, it is demonstrated that the solitary waves, under proper conditions, could be amplified or attenuated, even the solitary waves can propagate steadily in the microstructured solid layer, and the interaction of solitary waves does not influence their propagation characteristics.
The synthesis and thermoelectric properties of Yb/Sr double-atom-filled YbxSr8－xGa16Ge30 type-I clathrates
Authors: Cao Wei-Qiang  , Yan Yong-Gao  , Tang Xin-Feng  ,   武汉理工大学材料复合新技术国家重点实验室，武汉  430070
Published: December 2020

n-type Yb/Sr double-atom-filled YbxSr8-xGa16Ge30 (x=0, 05, 10, 15) clathrates have been synthesized by combining melting reaction with the spark plasma sintering (SPS) method. The effects of double-atom filling on thermoelectric properties have been investigated. The results show that the solubility limit of Yb in the Sr-Ga-Ge system is between 10 and 15 when it is expressed by the formula of YbxSr8-xGa16Ge30. With increasing Yb content x, the room-temperature carrier concentration of the YbxSr8-xGa16Ge30 samples increases, while the room-temperature carrier mobility decreases. For the double-atom-filled samples, the electrical conductivity raises with increasing x, while the Seebeck coefficient reduces, and in which the x=05 sample has a comparable electrical conductivity and a remarkably higher Seebeck coefficient compared with the single-atom-filled Sr8Ga16Ge30 sample in the temperature range of 300—800 K. The double-atom filling of Yb/Sr has significant influence on the lattice thermal conductivity of the YbxSr8-xGa16Ge30 samples and the lattice thermal conductivity decreases gradually with increasing x. Of all the YbxSr8-xGa16Ge30 samples, the maximum dimensionless figure of merit ZT of 081 is obtained at 800 K for the Yb10Sr70Ga16Ge30 sample. Compared with that of single-atom-filled Sr8Ga6Ge30 sample, it is 35% higher at the same temperature.
A prediction theory of record-breaking PDSI of China
Authors: Yang Jie  , Hou Wei  , Feng Guo-Lin  ,   (1)扬州大学物理科学与技术学院，扬州  225009；中国科学院大气物理研究所东亚区域气候-环境重点实验室，北京  100029；国家气候中心，中国气象局气候研究开放实验室，北京  100081; (2)中国科学院大气物理研究所东亚区域气候-环境重点实验室，北京  100029；国家气候中心，中国气象局气候研究开放实验室，北京  100081
Published: December 2020

The Palmer Drought Severity Index (PDSI) was calculated by using monthly air temperature and precipitation data in China during the period 1960 to 2007 Based on the monthly PDSI of 614 stations in China from 1960 to 2007, we theoretically study the statistics of record-breaking monthly PDSI (RBMP) in recent 48 years. According to the theory of record-breaking event, we have developed the universal mathematical formula to evaluate the record-breaking events. Based on the existing Gaussian distribution of monthly PDSI and the RBMP as the initial conditions, we compute the universal mean of the RBMP. Compared with the results of iterative calculations using the theoretical value, the values computed using the former method are closer to the real values. Then the next possible RBMP in the future are evaluated and predicted by the former method. The results show that the changes of extreme drought differ much in different regions of China and have obvious regional features. The drought trend in North China will continue, and the degree of extreme drought event of these regions are rising fast, extreme drought events more likely happen again in nearly two decades in the future. On the other hand, in South area, it is very improbable for more serious occurrence of extreme drought events in recent decades. The polarization trend in China will be further enhanced.
Coherence resonance in a nonlinear neuronal models driven by correlated colored noise
Authors: Liu Zhi-Hong  , Zhou Yu-Rong  , Zhang An-Ying  , Pang Xiao-Feng  ,   (1)电子科技大学生命科学与技术学院，成都  610054; (2)电子科技大学生命科学与技术学院，成都  610054；成都信息工程学院，成都  610225
Published: December 2020

The phenomenon of coherence resonance in a nonlinear integrate-and-fire neuronal model subject to correlated multiplicative synaptic and additive voltage-gated channel noise are investigated. Based on the adiabatic approximation theory and the unified colored approximation method，the analytic expression of the probability distribution of the first fire （FPD） and the coefficient of variation （CV） of the inter-spike interval of firing are obtained. It is shown that the FPD and the CV are functions of the intensity of the multiplication synaptic colored noise，the additive voltage-gated channel white noise，the correlation time of multiplicative noise and the strength of the correlation between noises. By choosing appropriate noise parameters，the phenomenon of coherence resonance can occur. Meanwhile，the effects of intensity of the multiplication synaptic noise，the additive voltage-gated channel noise，the correlation time of multiplicative noise and the strength of the correlation between noises on coherence resonance are discussed.
A kind of conserved quantity of Mei symmetry for general holonomic mechanical systems
Authors: Liu Yang-Kui  ,   陇东学院物理与电子工程学院，庆阳  745000
Published: December 2020

A kind of conserved quantity which directly results from the Mei symmetry of general holonomic mechanical system is studied in the paper. The definition and criterion of Mei symmetry for the general holonomic mechanical system are given. The conditions under which Mei symmetry can lead to a conserved quantity and the form of the conserved quantity are deduced. An example is given to illustrate the application of the result.
Static bifurcation of rain-wind-induced vibration of stay cable
Authors: Zhang Qi-Chang  , Li Wei-Yi  , Wang Wei  ,   天津大学机械工程学院力学系，天津  300072
Published: December 2020

The model of rain-wind-induced vibration of continuous stay cable is built on the basis of the dAlembert principle. This model can describe the dynamic characteristics of continuous stay cable better than the truncated model. By analyzing the static bifurcation behaviors according to the singularity theory，we describe the bifurcation problem as a one-codimensional unfolding with Z2 symmetry. The transition set and bifurcation diagrams for the singularity are presented，while the stability of the zero solution is studied using the eigenvalues in various parameter regions. The corresponding relationship between the unfolding parameters and the physical parameters will facilitates further analysis of the bifurcation behaviors of the stay cable，and it also provides theoretical basis for the design of cable stayed bridge. Meanwhile，it is helpful to the development and application of the engineering projects.
An all-fiber method to measure the wave-particle duality of light
Authors: Ma Hai-Qiang  , Li Lin-Xia  , Wang Su-Mei  , Wu Zhang-Bin  , Jiao Rong-Zhen  ,   (1)北京理工大学机械与车辆工程学院，北京  100081; (2)北京邮电大学理学院，北京  100876
Published: December 2020

A new scheme with very simple implementations giving obvious experimental results has been demonstrated to reveal the particle and wave duality of light. The scheme demonspates the wave property of light by coherent superposition and the particle property of light by random path selection though a 50/50 beam splitter. Preliminary experiments showed high interference visibility of 99% and the particle nature of light as high as 90% by using a highly attenuated pulsed laser as a single photon source. This scheme displays both the wave and particle nature of light though a simple experimental setup, which makes it a quite promising schem for revealing the property of light.
Analytical solutions to ultra-long waves with the complete Coriolis force and heating
Authors: Yang Jie  , Zhao Qiang  ,   北京大学物理学院，北京  100871
Published: December 2020

Ultra-long waves in the modified Burger model are studied by using the method of travelling-wave solution. Taylor series expansion is used to isolate the characteristics of linear waves and identify the nonlinear waves. The analytical solutions to nonlinear ultra-long waves with the complete Coriolis force and heating，which can be approximately described by the KdV equation and the combined KdV and mKdV （KdV-mKdV） equation，are obtained. The cnoidal waves，solitary waves，and soliton-like solutions are also obtained.
Effect of basis configuration on acoustic band structure in two-dimensional complex phononic crystals
Authors: Dong Hua-Feng  , Wu Fu-Gen  , Mu Zhong-Fei  , Zhong Hui-Lin  ,   广东工业大学实验教学部，物理与光电工程学院，广州  510090
Published: December 2020

The effect of basis configuration on acoustic band structure in two-dimensional complex phononic crystals （PCs） was investigated. We found that when the basis configuration was changed, the irreducible Brillouin zone （BZ） of PCs might be changed too，and part of band extrema were no longer on the high-symmetry lines. In particular，the PCs with some basis configurations were forced to render the whole first BZ irreducible. Therefore，besides the high symmetrical PCs，only by throughout investigation of the BZ can we obtain the authentic band structures and band gaps for the lower symmetrical PCs with complex crystal lattice.
Theoretical study on strain compensation layer for growth of quantum dots
Authors: Feng Hao  , Yu Zhong-Yuan  , Liu Yu-Min  , Lu Peng-Fei  , Jia Bo-Yong  , Yao Wen-Jie  , Tian Hong-Da  , Zhao Wei  , Xu Zi-Huan  ,   北京邮电大学信息光子学与光通信研究院，信息光子学与光通信教育部重点实验室，北京  100876
Published: December 2020

The optical properties of quantum dots have a close relationship with the size fluctuation，density，strain filed distribution of the dots and the spacer layer thickness. InAs/GaAs quantum dot with GaNXAs1-X strain compensation layers （SCL） is theoretically investigated for improving the crystal quality. The reduction effects of the spacer thickness are discussed quantitatively. The influence of the location and the N concentration of the GaNXAs1-X SCL on compensation of the strain formed on quantum dots （QDs） and the system is also discussed. The reduction effect of SCL on strain of system is analyzed and the vertical alignment probability between the adjacent layers is calculated. Our results can provide a theoretical basis for finding the optimal properties of SCL to realize the high quality multi-QD layer.
Cascaded image encryption systems based on physical chaos
Authors: Jin Jian-Xiu  , Qiu Shui-Sheng  ,   华南理工大学电子与信息学院，广州  510640
Published: December 2020

A cascaded encryption scheme using physical chaos is realized primarily, which combines chaotic encryption with data encryption standard. The difference of statistical properties of cipher text is studied for two cases. One case is that the ciphertexts come from different schemes, i.e. the cascaded and the single-stage ones, respectively. The other is that the ciphertexts are generated by chaotic signals with different unpredictability in the same scheme. Because physical chaos is adopted in this system, there is no assured relationship between plaintexts and ciphertexts, and the statistical characteristics of ciphertexts should be better than （or about equal to） that of any other encryption system. The experimental results support this conclusion, and show that the stronger unpredictability of chaotic signals causes the weaker correlation of ciphertexts.
Determination of the parameters of unknown signals based on intermittent chaos
Authors: Zhai Du-Qing  , Liu Chong-Xin  , Liu Yao  , Xu Zhe  ,   西安交通大学电气工程学院，西安  710049
Published: December 2020

We use the extreme frequency sensitivity of Duffing’s equation to produce intermittent chaos（we call it “breather”） and propose a new method to quantitatively detect the parameters of unknown weak periodic signals. The theoretical analysis and instance simulation have proved its feasibility. We also put forward a way to improve the detection results and enhance the accuracy.
Modularity matrix of networks and the measure of community structure
Authors: Wang Gao-Xia  , Shen Yi  ,   (1)华中科技大学系统工程研究所,武汉  430074; (2)三峡大学理学院,宜昌  443002；华中科技大学系统工程研究所,武汉  430074
Published: December 2020

The relationships between positive （negative） eigenspectrums and the structure properties of community （anti-community） of complex networks are investigated, and some corresponding definitions are given. By using the multieigenspectrums of modularity matrix of networks, a kind of structural centrality measure called the community centrality, is introduced. This individual centrality measure describes the strength that the individual adheres to the corresponding community. The measure is illustrated and compared with the standard centrality measures using several artificial networks and real world networks data. The results show that the community centrality has better discrimination, and it has positive correlation with the degree centrality.
Rate distortion model based on dual parameters Weibull distribution
Authors: Huo Yan  , Jing Tao  , Li Sheng-Hong  ,   (1)北京交通大学通信与信息系统北京市重点实验室，北京  100044; (2)上海交通大学电子工程系，上海  200240; (3)上海交通大学电子工程系，上海  200240；北京交通大学通信与信息系统北京市重点实验室，北京  100044
Published: December 2020

According to analysis of discrete cosine transform （DCT） coefficients of video sequence, a new DCT coefficients statistical model based on Weibull probability density function（PDF） is introduced. Compared with Laplacian PDF and Cauchy PDF, the model can describe properties of DCT of video sequences much better. In addition, according to the new statistical model and theory of entropy coding, the rate quantization （RQ） and distortion quantization （DQ） functions are proposed separately. Based on the simplified and approximate RQ and DQ which are obtained by the theory of rate distortion （RD） model and the properties of real video sequence, the novel RD model is presented. The experimental results show that the real video sequence encoded by intra or inter can be described much better by using rate distortion model based on Weibull PDF.
A three-phase four-leg topology of the new matrix converter
Authors: Wang Yong  , Guan Miao  , Zhang Lei  ,   北京航空航天大学自动化科学与电气工程学院，北京   100191
Published: December 2020

We present a three-phase four-leg matrix converter circuit topology, which can be used as three-phase four-wire AC voltage source to power the load imbalance. For the matrix converter topology, a novel indirect space vector modulation strategy is proposed, and the switch vector synthetic formula are deduced, giving a range of options, duty-cycle calculation and output reference voltage settings. Finally the new circuit topology for the simulation is studied. The results show that the circuit topology under three-phase unbalanced load can ensure sinusoidal output voltage waveform and stability.
Passive detection of upper atmospheric wind field based on the Lorentzian line shape profile
Authors: Zhang Lin  , Zhang Chun-Min  , Jian Xiao-Hua  ,   西安交通大学理学院，非平衡物质结构及量子调控教育部重点实验室,西安  710049
Published: December 2020

Taking the aurora in upper atmosphere as the detection source, we propose a new principle of passive detection of emission rate in upper atmosphere wind based on the Lorentzian line shape profile. Using this principle, we can detect not only the physical parameter of upper atmospheric wind such as velocity, temperature and pressure, but aslo the emission rate, which resolves the problem of detecting emission rate at present. The calculation formula of the distribution of the velocity, temperature, pressure and emission rate are deduced based on the Lorentzian line shape profile, and by using computer simulation, the error curve is described. This study provides a theoretical basis for further study of detection of upper atmospheric wind field. It will play a significant role and has a wide application prospect in aerospace, space exploration, and environmental protection.
Design and fabrication of micro multi-mirrors based on silicon for micro-spectrometer
Authors: Wang Bo  , Liang Zhong-Zhu  , Kong Yan-Mei  , Liang Jing-Qiu  , Fu Jian-Guo  , Zheng Ying  , Zhu Wan-Bin  , Lü Jin-Guang  , Wang Wei-Biao  , Pei Shu  , Zhang Jun  ,   (1)暨南大学光电工程系，广州  510632; (2)中国科学院长春光学精密机械与物理研究所应用光学国家重点实验室,长春  130033; (3)中国科学院长春光学精密机械与物理研究所应用光学国家重点实验室,长春  130033；中国科学院研究生院,北京  100049
Published: December 2020

A micro-spectrometer without moving parts that can be manufactured through micro-opto-electro-mechanical system techniques is developed, and the interference system is introduced. The fabrication of the micro multi-mirrors, which is the core part of the system, is investigated and wet etching of silicon in KOH solution is testified to be a good method. The root mean square surface roughness of the reflect surface made up of Si planes （111） through wet etching is less than 10 nm.
Entropy correction to Kerr-Newman black hole
Authors: Zeng Xiao-Xiong  ,   四川文理学院学报编辑部，达州  635000
Published: December 2020

Based on the work of Majhi et al., we investigate the entropy correction to the Kerr-Newman black hole beyond semiclassical approximation by the Dirac equation. Because in the units G=c=kB=1,the Planck constant is proportional to the square of Planck Length,Planck Mass and Planck Charge,the proportionality parameter of quantum correction terms to the semiclassical term of action is taken as (Mrh-Q2/2)-1. With the aid of the differential form of horizon equation and the first law of black hole thermodynamics,we obtain the corrected entropy of charged stationary black hole and find that the correction terms also include the logarithmic and inverse terms to Bekenstein-Hawking entropy.
Effects of the spin-orbit coupling on X-ray spectrum in special relativity
Authors: Yu Zhi-Qiang  , Xie Quan  , Xiao Qing-Quan  ,   贵州大学理学院,新型光电子材料与技术研究所，贵阳  550025
Published: December 2020

Based on special relativity, the formation mechanism of characteristic X\|ray was studied, and the influence of the spin-orbit coupling on the characteristic X\|ray wavelength was analyzed. A calculation formula of the X\|ray wavelength based on special relativity is obtained. Error analysis is carried out systematically for the calculation values of wavelength, and the rules of relative error are obtained. It is shown that the results of the calculation are very close to the experimental results, which have some reference meaning for spectrum analysis of characteristic X\|ray in application.
Momentum transfer cross sections of low-energy electron scattering from H2 molecule
Authors: Wang Xiao-Lian  , Feng Hao  , Sun Wei-Guo  , Fan Qun-Chao  , Zeng Yang-Yang  , Wang Bin  ,   (1)四川大学原子与分子物理研究所，成都  610065; (2)四川大学原子与分子物理研究所，成都  610065；西华大学物理与化学学院,先进计算研究中心，成都  610039; (3)西华大学物理与化学学院,先进计算研究中心，成都  610039
Published: December 2020

The momentum transfer cross sections （MTCSs） of low-energy electron scattering from H2 molecule are studied using the body frame vibrational close coupling method and the electrostatic potential, the exchange potential,and the correlated polarization potential calculated based on ab initio method. By considering the contributions of 18 Morse vibrational wave functions, 8 partial waves, and 16 molecular symmetries, we obtain the converged MTCSs of ν=0→ν′=0,1,2,3,4 transition excitations. The converged total MTCSs agree well with the recommended values of Elford et al., and are better than the previous theoretical studies in the eletron energy range of 1 eV<E≤10 eV.
Analysis and calculation of Glan-Taylor prism’s transmittance at full angle of view in a polarization interference imaging spectrometer
Authors: Zhang Chun-Min  , Liu Ning  , Wu Fu-Quan  ,   (1)曲阜师范大学激光研究所, 曲阜  273165; (2)西安交通大学理学院,非平衡物质结构与量子调控教育部重点实验室,西安  710049
Published: December 2020

The principle of the polarization interference imaging spectrometer （PIIS） developed in our laboratory is described. The principle of the beam splitting of Glan-Taylor prism which is one of the key components in the PIIS is analyzed. Using the ray-tracing method, we obtain the transmittance of Glan-Taylor prism at full angle of view. By computer simulation, we analyze the influence of the incidence plane, incidence angle and thickness of air gap on transmittance, and the dependence of the transmittance on wavelength is given in the spectral range which is required by the instrument system using Sellmeier dispersion equation. The transmittance of Grand-Taylor prism is tested in experiment, and the results are in good agreement with the theoretical results, so the correctness of the theory is verified.
Radiation characteristics of single wire array Z-pinch implosion
Authors: Xia Guang-Xin  , Zhang Fa-Qiang  , Xu Ze-Ping  , Xu Rong-Kun  , Chen Jin-Chuan  , Ning Jia-Min  ,   中国工程物理研究院核物理与化学研究所，绵阳  621900
Published: December 2020

Single wire array Z-pinch experiments were carried out on the 3—4 MA Angara-5-1 facility employing a set of diagnostic equipment, including an X-ray power meter with platform response to record X-ray emission bursts and a time resolved pinhole camera to obtain soft X-ray images. Experimental results indicated that when the diameter of wire array was fixed, implosions of arrays with smaller wire diameter started earlier and had a larger convergence ratio. In addition, when the wire gap was larger, the wire plasma could not merge effectively but moved inward individually at an early imploding stage, and larger wire diameter with larger wire gap had longer instability wavelength. The results also showed that when the wire diameter was fixed, implosions of arrays with larger diameter started earlier and had higher implosion speeds and wider plasma dispersion during implosions. Implosions of arrays with larger wire and array diameter had longer pulse X-ray width.
Target detection of saliency map based on pseudo Wigner-Ville distribution and Rényi entropy
Authors: Xu Yuan-Nan  , Zhao Yuan  , Liu Li-Ping  , Zhang Yu  , Sun Xiu-Dong  ,   哈尔滨工业大学物理系，哈尔滨  150001
Published: December 2020

Automatic target detection is always difficult in complex background. The Wigner-Ville distribution has a good characteristic that the images can be represented in spatial/spatial-frequency domains. Through the pseudo Wigner-Ville distribution, the statistical property of Rényi entropy is studied. The change of Rényi entropy’s statistical property in natural images when the man-made objects appear is analysed. Then a novel method for generating saliency map based on pseudo Wigner-Ville distribution and Rényi entropy is proposed. Target detection is performed when the saliency map is segmented using a simple and convenient threshold method. Experimental results show the proposed method can detect the military vehicles from complex earth background effectively.
Hadron-quark deconfinement phase transition in hybrid stars
Authors: Gong Wu-Kun , Guo Wen-Jun ,   College of Science, University of Shanghai for Science and Technology, Shanghai 200093, China
Published: December 2020

Astronomical statistics shows that the mass of neutron star is of the order of the solar mass, but the radius is only about ten kilometers. Therefore, the neutron star is highly condensed and there may be a variety of competing material phases inside the compact star. Hadron-quark deconfinement phase transition that is poorly understood at high density can be studied by the matter properties of hybrid star. The hybrid star contains many kinds of material phases, which cannot be described uniformly by one theory. So, different material phases are described by different theories. The hadronic phase is described by the relativistic mean-field theory with parameter set FSUGold including ω2ρ2 interaction term, and the quark phase is described by an effective mass bag model in which the quark mass is density-dependent. The hadron-quark mixed phase is constructed by the Gibbs phase transition, and the properties of hybrid star in β equilibrium is studied in this model. It is found that the bag constant B has a great influence on the starting point and ending point of the hadron-quark deconfinement phase transition and the particle composition in the hybrid star. Comparing with the starting point of phase transition, the influence of B on the ending point of phase transition is very obvious. For the hybrid star, the equation of state of matter becomes stiffer at low density and softer at high density as B increases. The overall effect is that the slope of the mass-radius curve increases with B increasing. The calculated results show that the maximum mass of hybrid star is between 1.3 solar mass and 1.4 solar mass (M☉), and the radius is between 9 km and 12 km. In addition, the influence of attractive and repulsive Σ potential on the properties of hybrid stars are studied. The results show that the Σ potential has a great influence on the particle composition in the hybrid star. We also find that the repulsive Σ potential makes the hybrid star have a greater maximum mass then an attractive Σ potential. For the attractive Σ potential, the maximum mass of hybrid star is 1.38M☉, while for the repulsive Σ potential, the maximum mass of hybrid stars is 1.41M☉.