bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of ion-channel interaction permeability of NaK channel
Authors: Zhang Su-Hua  , An Hai-Long  , Liu Yu-Zhi  , Zhang Zhen-Dong  , Geng Jin-Peng  , Zhan Yong  ,   (1)Hebei University of Technology, Tianjin 300130, China; (2)The Third Middle School of Tianjin, Tianjin 300131,China
Published: December 2020

Based on the three-dimensional structure of NaK channel, the permeabilities of the NaK channel for Na+, K+, Rb+, Ca2+ ions and the Ba2+ ion blockage mechanisms are investigated. The results show that the interaction is fundamental for determining the selectivities of the channels and the potential curve reflects the external behaviors for the permeabilities of different ions.
Spatiotemporal dynamic analysis of phase synchronized sources based on factor analysis
Authors: Li Ling  , Jin Zhen-Lan  , Li Bin  ,   (1)Key Laboratory for NeuroInformation of Ministry of Education, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 610054, China; (2)School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu 610054, China
Published: December 2020

Correlations in time courses of scalp electroencephalogram(EEG) may be represented by the phase synchronization in cerebral cortex sources to a certain some degree. Therefore, it is very important to localize the sources of phase synchronization and find corresponding time courses in the brain imaging study. Based on coupled Rössler oscillators with different coupling strengths, we propose a new method of simulating phase synchronized dipole sources and use a concentric 4-sphere head model to obtain simulation forward scalp EEG data. In addition, we propose the spatiotemporal dynamic analysis of phase synchronized sources based on the maximum likelihood factor analysis, verify the simulated and real scalp EEG data, and further compare the results with those of principal component analysis. Simulation results demonstrate that time courses estimated by maximum likelihood factor analysis have higher correlation with simulated sources, and less locational error between estimated sources and simulated sources. Factor analysis shows a better robust to the spatial resolution and the noise than principal component analysis. Furthermore, real data from spatial attention experiments show that factor analysis is capable of obtaining time courses and spatial distribution under the physiological base.
Complexity evolvement of a chaotic fractional-orderfinancial system
Authors: Xin Bao-Gui  , Chen Tong  , Liu Yan-Qin  ,   School of Management, Tianjin University, Tianjin 300072, China
Published: December 2020

A novel science branch, econophysics, is set up because various physical theories and methods are applied to economic and financial fields. More and more researchers are fascinated by the complex dynamical behavior of the fractional-order dynamical system. The paper analyzes the stability of the fractional-order financial system, and then simulates the generalized model complexity with Adams-Bashforth-Moulton predictor-corrector scheme by using bifurcation diagram, phase portrait and history time-series.
Brief research on economic impact assessment model for Shanghai urban transportation under durative extreme precipitation
Authors: Gong Zhi-Qiang  , Dong Wen-Jie  , Huang Yan  , Zhi Rong  ,   (1)College of Global Change and Earth System, Beijing Normal University, Beijing 100875, China; (2)Key Laboratory of Regional Climate-Environment Research for Temperate East Asia, Chinese Academy of Sciences, Beijing 100029, China; (3)Laboratory for Climate Studies, National Climate Center, China Meteorological Administration, Beijing 100081, China
Published: December 2020

Estimation models of economic losses due to flood are established by combining drainage times of urban road waterlogging-theoretical models and economic loss assessment models, etc. And then the "loss" curves are determined by discussing the relationships between daily mean precipitation and economic losses of urban transportation departments. Some socioeconomic variables, which are closely related to the anti-flood capability of urban transportation departments, are adopted in the models in this paper. By model testing, the economic loss assessment model established in this paper shows good simulation performance and applicability. And it has simple computation, needs few input variables, and is suited for the rapid assessment of the economic loss of some region. Based on the models established in this paper, the thresholds of the precipitation intensity and the total storm precipitation of each year in Shanghai are calculated. And a new definition of extreme precipitation, called "fixed thresholds varying with the influence factors", is given. This definition underlines the socioeconomic character of extreme precipitation which would cause economic loss and possesses high social practical values compared with other definitions of extreme precipitation.
A new method to detect abrupt change based on approximate entropy
Authors: Cheng Hai-Ying  , He Wen-Ping  , Zhang Wen  , Wu Qiong  , He Tao  ,   (1)Department of Basic Course, Yancheng Institute of Technology, Yancheng 224002, China; (2)JiNan Environment Protection Monitoring Station, Jinan 250014, China; (3)National Climate Center, China Meteorological Administration, Beijing 100081, China; (4)National Satellite Meteorological Center, China Meteorological Administration, Beijing 100081, China; (5)TongDa College, Nanjing University of post & telecommunications, Nanjing 210003, China
Published: December 2020

Approximate entropy (ApEn) is valid index which can be used to quantitatively reflect dynamic characteristics and complexity of a time series. The ApEn has been developed to detect an abrupt change in one-dimension time series by sliding a fixed widow, which can be identified with an abrupt dynamic change to some extent, but the sliding ApEn results depend on the window scale, and cannot accurately position the time-instant of an abrupt change. Based on this, a new method is proposed in the present paper, i.e., moving cut data-approximate entropy (MC-ApEn), which can be used to detect an abrupt dynamic change in time series. Tests on model time series indicate that the detection results from the present method show relatively good stability and high accuracy, obviously better than those from the sliding ApEn method and the Mann-Kendall method. The applications in daily precipitation records further verify the validity of the present method.
Critical magnetization of degenerate electronic system in neutron star
Authors: Lv Guo-Liang  , Wang Zhao-Jun  , Zhang Jun  , Zhu Chun-Hua  ,   (1)School of Physics, Xinjiang University, Urumqi 830046, China; (2)School of Science, Xi’ an Jiaotong University, Xi’ an 710049, China
Published: December 2020

Degenerate electronic Fermi system with intrinsic (spin) magnetic moment and Landau diamagnetic moment of the electrons in a neutron star interior is magnetized. Taking the magnetizing effect into consideration, the magnetic induced equation must be changed: the resulting equation has an additional magnetic induction term and a magnetic diffusion coefficient that is different from the original one for plasma. When effective magnetic diffusion coefficient equals critical value ( zero) the fully degenerate electronic system approaches a new phase. In this phase, the magnetic field of neutron star will become very large until other mechanisms suppress the increasing of the field in the neutron star lowered crust. For a stable or de Hass-Van Alphen oscillatory state, it is possible for the neutron star to become a magnetar .
Several auxiliary equations and infinite sequence exactsolutions to nonlinear evolution equations
Authors: Taogetusang  ,   The College of Mathematical Science, Inner Mongolia Normal University, Huhhot 010022, China
Published: December 2020

To seek infinite sequence exact solutions of nonlinear evolution equations, the Böcklund transformation of the solutions to some auxiliary equations and the formula of nonlinear superimposition of solutions are presented for constructing infinite sequence exact solutions to nonlinear evolution equations, which include infinite sequence Jacobi elliptic function solutions, infinite sequence hyperbolic function solutions and infinite sequence trigonomical function solutions. The method is of significance to the search into infinite sequence exact solutions of other nonlinear evolution equations.
Study of isotope effect in20Ne(34Ne)-18Na2(23Na2,37Na2) low-temperature collisions
Authors: Zang Hua-Ping  , Li Wen-Feng  , Linghu Rong-Feng  , Cheng Xin-Lu  , Yang Xiang-Dong  ,   (1)Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, China; (2)Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, China; School of Physics and Electronic Science, Guizhou Normal University, Guiyang 550001, China
Published: December 2020

Multiple ellipsoid model is applied to the20Ne,34Ne-18Na2,23Na2 and37Na2collision systems. The integral cross-sections for rotational excitation and total collision cross-sections at the incident energy of 190 meV are calculated. Moreover, at the related incident energy, the contributions of different regions of the potential to the integral cross-sections of rotational excitation for20Ne-18Na2,23Na2 and37Na2 collision systems are investigated. By analyzing the differences of these integral cross-sections, the change rules of the integral cross sections with the change of rotational angular quantum number of Na2 molecule, as well as with the change of the reduced mass of symmetric isotopic substituted system are obtained.
The theoretical and experimental investigation of repumping laser impact on cooling and trapping of strontium atoms
Authors: Gao Feng  , Chang Hong  , Wang Xin-Liang  , Tian Xiao  , Zhang Shou-Gang  ,   (1)National Time Service Center, Chinese Academy of Sciences, Key Laboratory of Time and Frequency Primary Standards of Chinese Academy of Sciences, Xi'an 710600, China; (2)National Time Service Center, Chinese Academy of Sciences, Key Laboratory of Time and Frequency Primary Standards of Chinese Academy of Sciences, Xi'an 710600, China; Graduate University of Chinese Academy of Sciences, Beijing 100049, China
Published: December 2020

We have conducted experimental investigations on the effect of repumping laser on the cooling and trapping of strontium atoms. More than 3.1×10888Sr atoms have been trapped with 679 nm and 707 nm repumping laser added. The two repumping lasers enhance the trappopulation by a factor of 17. We also made experimental investigations on the effect of 707 nm repumping laser detuning on the cooling and trapping of strontium atoms. The fluctuation of atom trapping population is less than 3 ‰ when the detuning from 707 nm is 5 MHz.
High pressure Raman investigation on the Fermi resonance of biphenyl
Authors: Zhou Mi  , Li Zhan-Long  , Lu Guo-Hui  , Li Dong-Fei  , Sun Cheng-Lin  , Gao Shu-Qin  , Li Zuo-Wei  ,   State Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun 130012, China
Published: December 2020

Raman spectra of biphenyl have been obtained under pressures up to 15 GPa. The results indicated that with the increase of pressure, the effect of inter- and intra-molecular π-πconjugation and delocation increases, accompanied by the intensity enhancement of the Raman bands, and blue shift of the frequency. The intensity ratio (Rf/a) of two Fermi resonance bands υ'6 + υ' 1 and υ' 8 decreases, and the frequency difference Δ increases with the pressure. The Fermi resonance phenomenon disappears when the pressure goos up to 8 GPa. Using J.F. Bertran's theory, we obtained the relationship of the inherent frequency difference Δ0 and coupling coefficient ω with pressure. This phenomenon was explained by high-pressure phase transition. The mechanism of high pressure induced Fermi resonance weakening was also discussed.
Theoretical calculation of photonization of F3+ and Ne4+ ions
Authors: Sun Chang-Ping  , Wang Guo-Li  , Zhou Xiao-Xin  ,   Key Laboratory of Atomic and Molecular Physics & Functional Materials of Gansu Province, College of Physics and Electronic Engineering, Northwest Normal University, Lanzhou 730070, China
Published: December 2020

We have calculated the partial and total photoionization cross sections for ground states 2s22p2 (3P) and excited states 2s22p2(1D,1S) ,2s2p3 (5So) of F3+ and Ne4+ ions and analyzed and identified the corresponding transitions of autoionization resonances for the ions in the photoionization processes. The obtained resonance structures of total photoionization cross sections are compared with the recent experimental ones and other theoretical calculations. It is shown that our results are in good agreement with the recent experimental ones.
Study of the photodetachment of H- in a microcavity
Authors: Tang Tian-Tian  , Wang De-Hua  , Huang Kai-Yun  ,   College of Physics, Ludong University, Yantai 264025, China
Published: December 2020

Using the closed orbit theory, we studied the photodetachment cross section of H- in a microcavity, which is made of two parallel metal and elastic surfaces. The results show that both the upper and lower surfaces of the microcavity have great influence on the photodetachment cross section of H-. If we fix the distance between the metal surface and H-, when the distance between the elastic surface and H- is large, the influence of the elastic surface on the photodetachment cross section is small. The oscillation amplitude and the oscillation frequency of the cross section approach to the case of the photodetachment of H- near a metal surface. With the decrease of the distance between the elastic surface and H-, the oscillation amplitude is increased and the oscillation frequency is decreased. If we fix the distance between the elastic surface and H-, with the increase of the distance d0 between the metal surface and H-, the influence of the metal surface is decreased. When the d0 is increased to 500 a.u. the cross section approaches to the case of the photodetachment of H- near an elastic surface. So we can change the distance between the upper and lower surface of the microcavity to control the photodetachment of H-. This study provides a new understanding on the photodetachment process of H- in the presence of surfaces and microcavity.
The radiation pressure and laser cooling of a V-type three level atom
Authors: Zhang Qin  , Jin Kang  , Tang Yuan-He  , Qu Guang-Hui  ,   (1)Department of Physics , Xi’an University of Technology , Xi’an 710054, China; (2)Department of Physics, Northwest University, Xi’an 710069, China
Published: December 2020

The radiation pressure and laser cooling of a V-type three level atom in coherent fields in a squeezed vacuum are considered. From the Hamiltonian of the atomic system, making use of Born-Markoff approximation, the optical Bloch equations are derived. Using the adiabatic approximation, the expression of the mean dissipative force are acquired. The achievable equilibrium temperature is given by the quantum regression theorem and Einstein relation. The dependence of the spontaneous radiation pressure and ultimate temperature on quantum interference, average photon number and Rabi frequency are analyzed. The result shows that temperatures lower than the Doppler limit can be achieved.
Nonsequential double ionization of argon atom below the recollision threshold
Authors: Zhang Dong-Ling  , Tang Qing-Bin  , Yu Ben-Hai  , Chen Dong  ,   College of Physics and Electronic Engineering, Xinyang Normal University, Xinyang 464000 China
Published: December 2020

Nonsequential double ionization (NSDI) of Ar atom below the recollision threshold is investigated using the three-dimensional classical ensembles. The calculated results reveal a dominance of events for electron emission into opposite hemispheres, a clear minimum of the correlated electron-electron momentum distributions at the origin and a single peak structure of the Ar2+ ions longitudinal momentum spectra near zero momentum. The momentum spectra of the Ar2+ ions agree with the experimental results 101 053001 (2008)] quantitatively. Trajectory back analyses show that the microscopic physical mechanisms of Ar NSDI are distinct for different intensities of the laser. When laser intensity equal to 0.7×1014 W/cm2, one recollision dominates the process of the recollision. However,the domination convert to multiple recollisions as the laser intensity decreases to 0.4×1014 W/cm2. In addition, the Coulomb attraction between the ion and electron plays an important role in microscopic dynamics of the electron in the process of Ar NSDI and eventually influences the final-state correlated electron-electron momentum distributions strongly.
Orientation-enhanced and holographic storage of a novel azobenzene doped polymer
Authors: Xie Ru-Sheng  , Zhao You-Yuan  ,   (1)Department of Optical Science and Engineering, School of Information Science and Engineering, Fudan University, Shanghai 200433, China; (2)Department of Optical Science and Engineering, School of Information Science and Engineering, Fudan University, Shanghai 200433, China; Fujian Bioengineering Vocational and Tehnical College, Fuzhao 350002, China
Published: December 2020

A novel optical high-density storage material ADPA-PVK-PBA-TNF polymer film was reported. In the nonresonant absorption of sample, we tested and investigated its photo-induced birefringence and obtained the value Δn =1.3×10-3.We analyzed the physico-chemiscal mechanism of orientation-enhancement and discussed the enhancing/restraining effects of photo-induced birefringence in the film. On this basis,multiple angles storage were achieved and clear holographic storage images were gained. The enhancing/restraining effect of image storage was also discussed. And with the help of this effect one can process and remove storage images.
The study on the produced length of whispering-gallery-mode fiber laser
Authors: Zhu Kun  , Zhou Li  , You Hong-Hai  , Jiang Nan  , Pu Xiao-Yun  ,   Department of Physics, Yunnan University, Kunming 650091, China
Published: December 2020

Long length of whispering-gallery-mode fiber lasing emission along a fiber's axis is obtained by using the method of evanescence-wave optically pumped and gain coupled fiber laser. The relationship between produced length of lasing emission and pumping energy has been investigated. With the increasing of pumping energy, it is found from our experiment that the length of whispering-gallery-mode lasing emission along the fiber's axis is increased sharply, when the pumping energy is just larger than the threshold energy. However, the increasing trend of the produced length is slow when the pumping energy is much larger than the threshold energy. It was also found from the experiment that both dye concentration and refractive index of cladding gain solution have key affects on the produced length. Based on the characteristic of frustrated totally internal reflection of light traveling along the fiber, and the theory of evanescence-wave pumped and gain coupled fiber laser, an equation determining the produced length of lasing emission has been deduced, the calculated result with the equation matches the experimental data very well.
Carrier-envelope stabilized few-cycle infrared laser system
Authors: Song Li-Wei  , Li Chuang  , Wang Ding  , Xu Can-Hua  , Leng Yu-Xin  , Li Ru-Xin  ,   State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China
Published: December 2020

According to the feature of the passive carrier-envelope phase (CEP) stabilized idler of the optical parametric amplified process, a CEP stabilized three-stage collinear optical parametric amplifier is built. Millijoule ultrashort infrared output (1.4 mJ/40 fs/1 kHz at 1.8 μm) with CEP fluctuation ~516mrad is obtained from the system. After passing through a hollow-core fiber and block material, the pulses are finally compressed to less than two cycles (<12 fs), and the single pulse energy is 0.54mJ. The system provides an excellent laser source for the experiments of individual attosecond pulse generation and other high harmonic generation (HHG).
Investigation on the fabrication and luminescence characteristics of Yb3+ and Al3+ Co-doped silicate glasses
Authors: Han Ying  , Zhou Gui-Yao  , Xia Chang-Ming  , Hou Zhi-Yun  , Hou Lan-Tian  ,   College of Information Science and Engineering, Yanshan University, Qinhuangdao 066004,China;,   College of Information Science and Engineering, Yanshan University, Qinhuangdao 066004,China; Key Laboratory of Metastable Material Science and Technology, Yanshan University, Qinhuangdao 066004,China;,   College of Information Science and Engineering, Yanshan University, Qinhuangdao 066004,China; Key Laboratory of Metastable Material Science and Technology, Yanshan University, Qinhuangdao 066004,China; School for Infromation and Optoelectronic Science and;,   College of Information Science and Engineering, Yanshan University, Qinhuangdao 066004,China; School for Infromation and Optoelectronic Science and Enginering, South China Normal University, Guangzhou 510006,China
Published: December 2020

We demonstrate a new method for fabrication of rare-doped silica-based glass, which is liquid doped with non-chemical vapor deposition (non-CVD) melting process. The Ytterbium doped silica-based glass with the ratio of 98SiO2-0.5Yb2O3-1.5Al2O3wt% is achieved by using this method. The refractive index (nD) and the density(ρ) of the glass are 1.519 and 2.62g/cm3 respectively. In measurement experiment, it shows that it has strong absorption in the wavelength range from 850nm to 1050nm, and the main absorption peak is at 978nm and the secondary absorption peak is at 919nm. Using the laser with wavelength of 978nm as pumping source, the emission peak is at 1018nm in the fluorescence spectrum with a 71.8nm fluorescence half-line width. Meanwhile, the integrated absorption cross section, stimulated emission cross section, fluorescence time, saturated pump intensity, minimum pump intensity and other parameters are calculated. Test results indicate that the doped silica-based glass has good thermal stability and large power threshold, which is an ideal gain medium for large power photonic crystal fiber lasers.
Parametric analytical model for off-axis illumination sources based on Sigmoid function
Authors: Liu Wei  , Liu Shi-Yuan  , Wu Xiao-Fei  , Zhang Chuan-Wei  ,   (1)Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074, China; (2)Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074, China; State Key Laboratory of Digital Manufacturing Equipment and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
Published: December 2020

This paper proposes a parametric analytical source model for overall representation of the physical distribution property of off-axis illumination sources in lithographic tools. A Sigmoid function is adopted as a kernel function to construct the analytical model for the multiple mainstream off-axis sources. Corrected parametrical terms are subsequently presented for characterization of different physical distortions and deviations of real illumination sources. The corrected parametrical terms can be decomposed into Fourier series which have the special physical meaning of respectively indicating different distortion types including shift of the center, tilt, ellipticity, etc. The proposed analytical model provides both simulation condition and theoretical basis for the resolution enhancement technique and the related research fields, thus has important applications.
Study on attenuation characteristics of millimeterwave in plasma
Authors: Luo Xian-Gang  , Ma Chun-Guang  , Liu Jian-Wei  , Zhao Qing  , He Guo  , Zheng Ling  ,   (1)Institute of Optics and Electronics, Chinese Academy of Sciences, Chengdu 610209, China; (2)School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu 610054, China
Published: December 2020

In order to study the interaction between millimeter wave and plasma, by using time-domain integration method to simulate the attenuation characteristics of millimeter wave propagation in the plasma ,this paper makes preliminary study on the relationships betwcen the attenuation value of millimeter waves propagation in the plasma, plasma density, the collision frequency and operation frequency. By comparing and analyzing the theoretical results with simulation results, the feasibility of the fact that simulation can be used to provide data support for the theoretical study is verified.
Transport properties of titanium and silver plasmas in the region of partial ionization
Authors: Chen Xiang-Rong  , Fu Zhi-Jian  , Chen Qi-Feng  ,   (1)National Key Laboratory of Shock Wave and Detonation Physics, Institute of Fluid Physics, Chinese Academy of Engineering Physics, Mianyang 621900, China; (2)School of Physical Science and Technology, Sichuan University, Chengdu 610064, China; (3)School of Physical Science and Technology, Sichuan University, Chengdu 610064, China; National Key Laboratory of Shock Wave and Detonation Physics, Institute of Fluid Physics, Chinese Academy of Engineering Physics, Mianyang 621900, China
Published: December 2020

The composition of metal plasmas provides the fundamental parameters for the thermodynamic, optical, and transport properties research. In this paper, the composition of the plasmas, considering the threefold ionization of metal, the polarization between neutral particles and electron, and the Coulomb interactions among the charge particles, (including ion-ion, electron-ion, and electron-electron interactions), is calculated by partially ionized plasma model. Furthermore, the electrical conductivities of titanium and silver are calculated by using linear response theory. The reliability of the model is verified by comparing with available experimental data. Furthermore, the thermal conductivities and thermopower of titanium and silver in the range of 0.001—2.0 g/cm3, 1.5×104—2.5×104 K are predicted, which provides the reference for the experiment of transport properties of metal plasmas.
Numerical and experimental study of air arc splitting process considering splitter plate erosion
Authors: Yang Fei  , Rong Ming-Zhe  , Wu Yi  , Shi Qiang  , Liu Zeng-Chao  , Ma Rui-Guang  , Chen Sheng  ,   State Key Lab of Electrical Insulation and Power Equipment, Xi’an Jiaotong University, Xi’an 710049,China
Published: December 2020

A three-dimensional magnetohydrodynamic model of an air arc plasma, considering the metal vapour from erosion of an iron splitter plate, is developed. An equation describing conservation of the iron vapour mass is added to the standard mass, momentum, and energy conservation equations. The influence of the iron vapour on the thermodynamic and transport properties of the gas mixture is considered in the calculation. The arc voltage, and distributions of temperature, gas flow, and mass fraction of iron vapour in the arc chamber are calculated and analyzed in detail. The experiment was carried out to support the simulation work. The images recorded by a high-speed camera and arc voltage measurement were compared with the predictions of the simulations, which proved the validity of the simulation model.
Research on interface and fractal characteristics of PI/Al2O3Films by SAXS
Authors: Fan Yong  , Bu Wen-Bin  , Liu Xiao-Xu  , Cheng Wei-Dong  , Wu Zhong-Hua  , Yin Jing-Hua  ,   (1)BSRF Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China; (2)School of Applied Science, Harbin University of Science and Technology, Harbin 150080, China; (3)School of Applied Science, Harbin University of Science and Technology, Harbin 150080, China; Heilongjiang Institutes of Science and Technology, Harbin 150027, China; (4)School of Applied Science, Harbin University of Science and Technology, Harbin 150080, China; Key Laboratory of Engineering Dielectric a
Published: December 2020

Inorganic nano-composite polyimide (PI) films were prepared with the method of sol-gel. The interfacial situation and the fractal characteristics of PI films were investigated by small angle X-ray scattering (SAXS) using synchrotron radiation as X-ray source. SAXS results indicated that the scattering curves in the high-angle region have a negative slope, i.e., a negative deviation from Porod's law, which suggests that there are obvious interface layers between the organic phase and the inorganic phase in the PI films. The thicknesses of interface layers are 0.54—1.48 nm. The interaction of the organic phase and inorganic phase becomes stronger and the thickness of interfacial layer increases with the increase of inorganic nano-components. Nano-particles have mass fractal, simultaneously have surface fractal structure, and their distribution and assemblage are nonlinear dynamic processes. With the inorganic nano-components increasing, the surface fractal dimension increases and mass fractal dimension decreases, which shows that the nano-particles structure becomes looser and mass distribution becomes more uneven. The anchoring action of polymer chains is enhanced and the number of anchored point increased respectively, the surface of the hybrid PI films becomes rougher. Finally, according to the interface characteristics of hybrid PI films, the relationship of the breakdown field strength with component is analyzed by percolation theory and polarization theory.
Distributed-feedback lasing from dye-doped holographic polymer dispersed liquid crystal transmission grating
Authors: Deng Shu-Peng  , Li Wen-Cui  , Huang Wen-Bin  , Liu Yong-Gang  , Lu Xing-Hai  , Xuan Li  ,   (1)State Key Laboratory of Applied Optics,Changchun Institute of Optics, Fine Mechanics and Physics,Chinese Academy of Sciences, Changchun 130033, China; (2)State Key Laboratory of Applied Optics,Changchun Institute of Optics, Fine Mechanics and Physics,Chinese Academy of Sciences, Changchun 130033, China; Graduate School of Chinese Academy of Sciences, Beijing 100049, China
Published: December 2020

In this paper,we report the fabrication of dye-doped holographic polymer dispersed liquid crystal(HPDLC) transmission grating and the property of distributed-feedback lasing from dye-doped HPDLC transmission grating. Under the excitation of a frequency-doubled Nd:yttrium-aluminum-garnet laser operating at a wavelength of 532 nm, optically pumped lasing with narrow linewidth and low threshold was observed from a DCM dye-doped HPDLC transmission grating with the grating period of 586 nm. The results showed that the emitted lasing peak centered at about 603 nm with a full width at half maximum (FWHM) of only 1.4 nm, and the threshold pumping intensity was about 17.3 μJ, which is evidently lower than the previously reported values.
Influence of high-dose nitrogen implantation on the positive charge density of the buried oxide of silicon-on-insulator wafers
Authors: Zhang En-Xia  , Tang Hai-Ma  , Zheng Zhong-Shan  , Yu Fang  , Li Ning  , Wang Ning-Juan  , Li Guo-Hua  , Ma Hong-Zhi  ,   (1)College of Material Engineering, Shanghai University of Engineering Science, Shanghai 201620, China; (2)Department of Physics, University of Jinan, Jinan 250022, China; (3)Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
Published: December 2020

The influence of nitrogen implantation on the properties of silicon-on-insulator buried oxide using separation by oxygen implantation was studied. Nitrogen ions were implanted into the buried oxide layer with a high-dose of 1016 cm-2. The experimental results showed that the positive charge density of the nitrogen-implanted buried oxide was obviously increased, compared with the control sampes without nitrogen implantation. It was also found that the post-implantation annealing caused an additional increase of the positive charge density in the nitrogen implanted samples. However, annealing time displayed a small effect on the positive charge density of the nitrogen implanted buried oxide, compared with the significant increase induced by nitrogen implantation. Moreover, the capacitance-voltage results showed that the positive charge density of the unannealed sample with nitrogen implanted is approximately equal to that of the sample annealed at 1100 ℃ for 2.5 h in N2 ambient, despite an additional increase brought with annealing, and the buried oxide of the sample after 0.5 h annealing has a maximum value of positive charge density. According to the simulating results, the nitrogen implantation resulted in a heavy damage to the buried oxide, a lot of silicon and oxygen vacancies were introduced in the buried oxide during implantation. However, the Fourier transform infrared spectroscopy of the samples indicates that implantation induced defects can be basically eliminated after an annealing at 1100 ℃ for 0.5 h. The increase of the positive charge density of the nitrogen implanted buried oxide is ascribed to the accumulation of implanted nitrogen near the interface of buried oxide and silicon, which caused the break of weak Si-Si bonds and the production of positive silicon ions in the silicon-rich region of the buried oxide near the interface, and this conclusion is supported by the results of secondary ion mass spectrometry.
New material exploration and magnetism researchon Heusler alloys Cr-Co-Ga
Authors: Liu En-Ke  , Tang Xiao-Dan  , Wang Wen-Hong  , Wu Guang-Heng  , Meng Fan-Bin  , Liu He-Yan  , Luo Hong-Zhi  , Qian Jin-Feng  , Feng Lin  , Zhu Wei  ,   (1)Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; (2)School of Material Science and Engineering, Hebei University of Technology, Tianjin 300130, China
Published: December 2020

The crystal structure, magnetism and transport properties of a series alloys from Co2CrGa to Cr2CoGa (Co50-xCrx+25Ga25, x=0—25) have been investigated by the experimental and KKR-CPA-LDA calculation methods. Substituting Cr for Co atoms, the crystal structure changes from L21 type to Hg2CuTi structure, which make, the lattice parameters increase about 0.69% linearly. Also, the ferromagnetic coupling turns to anti-ferromagnetic coupling, that makes the magnetic moment linearly decrease from 3.06μB to nearly zero. Through ab initio study of CPA, it has been found that the extraneous Cr atom at the A site couples anti-ferromagnetically with the Cr atom originally situated at B site with a nearly equal magnitude of magnetic moment, and the magnetic moment of Co atoms occupying the C site decreases from 0.60μB to 0.21μB through the whole substituting process. Based on the results of magnetic measurement and calculation, about 20% atomic disorder in the alloy Cr2CoGa has been confirmed, which is consistent with the observation of the X-ray examination. It is interesting that a non-linear "middle component phenomenon" has been observed in the composition dependence of both Curie temperature and the electrical resistivity. The related discussions is based on the magnetic environment change surrounding the magnetic atoms.
The eigenvalues of quantized spin waves and theeffect of the uniaxial anisotropy
Authors: Hou Xiao-Juan  , Yun Guo-Hong  , Bai Yu-Hao  , Bai Narsu  , Zhou Wen-Ping  ,   College of Physical Science and Technology, Inner Mongolia University, Hohhot 010021, China;,   College of Physical Science and Technology, Inner Mongolia University, Hohhot 010021, China; Department of Applied Physics, School of Mathematics, Physics and Biological Engineering, Inner Mongolia University of Science and Technology, Baotou 014010, Chin;,   College of Physical Science and Technology, Inner Mongolia University, Hohhot 010021, China; Inner Mongolia Key Laboratory of Physics and Chemistry of Functional Materials, College of Physics andElectronic Information, Inner Mongolia Normal University, Ho;,   Inner Mongolia Key Laboratory of Physics and Chemistry of Functional Materials, College of Physics andElectronic Information, Inner Mongolia Normal University, Hohhot 010022, China
Published: December 2020

The eigenproblems of quantized spin waves in a (100) ferromagnetic bilayer system have been investigated theoretically by using the interface rescaling approach. The energy-band structure of the system has been obtained and the effect of the uniaxial bulk anisotropy field of easy-axis type on the energy bands were explored thoroughly. It is found that there are bulk modes, perfect confined modes and interface modes in the biferromagnetic system, the existing condition of which is determined not only by the bulk exchange coupling constant, the interface exchange coupling constant, the spin of lattice, the number of atomic layers, but also by the uniaxial bulk anisotropy.
Electronic structure and optical properties of Ag-doping and Zn vacancy impurities in ZnS
Authors: Li Jian-Hua  , Zeng Xiang-Hua  , Ji Zheng-Hua  , Hu Yi-Pei  , Chen Bao  , Fan Yu-Pei  ,   College of Physics Science and Technology, Yangzhou University, Yangzhou 225002, China
Published: December 2020

The geometrical structures of Ag-doped ZnS, that with Zn vacancies and pure zinc blend were optimized by means of plane wave pseudo-potential method (PWP) with generalized gradient approximation (GGA). The electronic structure and optical properties of the three systems were calculated and the reason why p type ZnS is difficult to form was given theoretically. Equilibrium lattice constant, band structure, electronic structures and optical properties were discussed in detail. The results reveal that,in Ag-doped ZnS and Zn vacancy systems, due to the introduction of the defect level, the band gap is reduced and electronic transition in the visible region is obviously enhanced.
Effect of Dy additive on microstructure and magnetic propertiesof rapidly solidified Nd-Fe-B strips
Authors: Ding Yong  , Chen Ren-Jie  , Guo Shuai  , Liu Xing-Ming  , Lee Dong  , Yan A-Ru  ,   Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Zhe Jiang Province Key Laboratoryof Magnetic Materials and Application Technology, Ningbo 315201, China
Published: December 2020

Sintered Nd-Fe-B magnets made from strip cast alloys have been studied extensively owing to their strong permanent magnetic properties. Up to now the studies mainly focus on technology parameters of strip casting, including casting temperature, wheel speed and phase transition temperature and so on. However, microstructure and properties of rapidly solidified strips could be influenced by the composition of alloy. In this work, the effects of added Dy element on microstructures and properties of Nd-Fe-B rapidly solidified strips have been investigated. The strips shad a pronounced texture of the tetragonal T1(2 ∶14 ∶1) phase as shown by the prominent (00l) peaks at wheel surface. The alignment coefficient of the strips was the highest when Dy content ranged from 1 to 2at%. This is the result of the microstructure of strips being optimized through an appropriate amount of Dy addition. At the same time, the volume fraction of isotropic crystal decreased as Dy content increased. It revealed that the oxidation speed decreased with increasing Dy content.
Growth and chracterization of Zn1- x-y Na x Co y O thinfilms prepared by pulsed laser deposition
Authors: Tao Ye-Wei  , Li Shi-Shuai  , Feng Xiu-Peng  , Huang Jin-Zhao  , Liu Chun-Yan  , Zhang Zhong  ,   (1)School of Science, Nanjing University of Posts and Telecommunications, Nanjing 210003, China; (2)School of Science, University of Jinan, Jinan 250022, China
Published: December 2020

Zn1-x-yNaxCoyO thin films were prepared by pulsed laser deposition (PLD) on Si(111) substrates. The X-ray diffraction(XRD), atomic force microscopy(AFM), fluorescence spectrometer and the Four-probe tester were used respectively to investigate the structure, surface structure, optical and electrical properties of the thin films. The optical and electrical properties of Zn1-x-yNaxCoyO doped with different Na-Co concentrations are investigated. The result indicates that the structure of films are zincite and the doping of Na-Co leads to the red-shift of the UV emission peak of ZnO. When the doping concentration of both Na and Go are 10%, the film has the highest fluoresence intensity located at 397 nm, and the lowest resistivity of 8.34×10-1 Ω ·cm is detected in this film. The reasons of above-mentioned phenomena are discussed in depth.
The Jahn-Teller effect and energy-level splitting for C2+4molecules with the D4h symmetry configuration
Authors: Feng Sheng-Qi  , Qiu Qing-Chun  ,   (1)Department of Physics and Electronic Engineering, Hanshan Normal University, Chaozhou 521041, China; (2)Department of Physics and Informatics, Medical College, Shantou University, Shantou 515041, China
Published: December 2020

Based on quantum theory and ligand field theory, the E×(b1g+b2g) Jahn-Teller system for C2+4 molecules with the D4h symmetry configuration was studied in this paper using the methods of group theory and symmetry analysis. The symmetry of electronic states and phonon states for the system were explored, the coupling between phonons and CG coefficients were discussed, and the vibronic Hamiltonian for the E×(b1g+b2g) Jahn-Teller system was constructed. The ground state of the system and its energy were calculated using unitary shift transformation. It was found that there were four minima on the potential energy surface of the system because of the vibronic coupling. No matter which minimum the system is in, the ground energy level of the system is split into two energy levels after the Jahn-Teller distortion and the electronic degeneracy of the system is completely lifted. The Jahn-Teller distortion direction for the system was studied further using group theory. The results show that the distortion direction of the system should be D4h→D2h, and the symmetry of the ground state for C2+4 molecules is B1uunder the group D2h after the Jahn-Teller distortion.
Effect of carrier recombination on time-resolved Faraday rotation spectroscopy in GaAs quantum wells
Authors: Teng Li-Hua  , Wang Xia  ,   School of Mathematics and Physics, Qingdao University of Scienced and Technology, Qingdao 266061 China
Published: December 2020

Based on the rate equations of a two-level system, time-resolved Faraday rotation spectroscopy model was developed. It was found that the carrier recombination has strong effect on the decay of Faraday rotation signal. The model was also used to fit the Faraday rotation spectra measured in GaAs quantum wells. The electron spin relaxation time was obtained as 73.5 ps. However, the spin relaxation time was obtained only as 51.3 ps with the single exponent to fit the Faraday rotation spectra. Thus, the conventional method with the single exponent to fit the Faraday rotation spectra is inaccurate.
Influence of interdot-coupling on differentialconductance for a triple quantum dot
Authors: Ju Xin  , Guo Jian-Hong  ,   Center of Theoretical Physics, Department of Physics, Capital Normal University, Beijing 100048, China
Published: December 2020

Using the method of equation of motion of nonequilibrium Green's function, we study the Aharonov-Bohm effect of differential conductance of electronic transport through a triple quantum dot system in which two quantum dots are directly coupled to the electrodes. We found that the conductance or tunneling property depends on the different values of local density of states. Moreover, electron transport through the system can be influenced by inter-dot coupling and energy level of each dot.
Microstructures and magnetic analyses of Al/ZnO/Al thin films
Authors: Qi Yun-Kai  , Gu Jian-Jun  , Liu Li-Hu  , Zhang Hai-Feng  , Xu Qin  , Sun Hui-Yuan  ,   (1)College of Physics Science & Information Engineering, Hebei Normal University, Shijiazhuang 050016, China; Department of Physics, Hebei Normal University for Nationalities, Chengde 067000, China; (2)College of Physics Science & Information Engineering, Hebei Normal University, Shijiazhuang 050016, China; Key Laboratory of Advanced Films of Hebei Province, Shijiazhuang 050016, China; Department of Physics, Hebei Normal University for Nationalities, Ch
Published: December 2020

Al/ZnO/Al thin films are prepared on the glass substrates by dc magnetron sputtering and annealed in vacuum and atmosphere, separately. The crystal structures are analyzed by X-ray diffraction (XRD), and the magnetic properties are measured by a Physical Properties Measurement System (PPMS) with a magnetic field parallel to the films plane. The XRD results indicate that the microstructures of thin films are greatly influenced by the annealing aura. In this paper, an improved corrected method to subtract the signal of the substrate is suggested. Simultaneously, the maximum fitting error of substrate is calculated, and the magnetic properties of the modified films are discussed. The results show that the room temperature ferromagnetism may be related to the charge transfer between Al and Zn and the variational position of Al in ZnO films in different annealing conditions.
Molecular dynamics simulation of energy exchange during hydrogen collision with graphite sheet containing a vacancy
Authors: Li Shou-Yang  , Sun Ji-Zhong  , Zhang Zhi-Hai  , Liu Sheng-Guang  , Wang De-Zhen  ,   School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024, China
Published: December 2020

Molecular dynamics simulation is applied to investigation of energy exchanges during hydrogen collision with graphite sheet containing a vacancy. The effects of the monovancancy defect on the energy exchanges are discussed in detail. This paper analyzes the energy loss of the incident hydrogen atom, the energy range for the adsorption process, and the energy transfer process for target atom, in the course of a hydrogen atom bombarding the carbon atom at the edge of monovacancy defect in the graphite sheet. The simulation results show that the adsorption process proceeds more easily when the graphite sheet contains a vacancy than when the graphite sheet has perfect crystalline structure. In certain areas of the graphite sheet, adsorption of an incident hydrogen atom can occur in two energy ranges. The sp2 structure as well as overhang configuration occurs when a hydrogen atom is adsorbed. This adsorption process does not reduce the C—C bond energy. It is found that the carbon atom at the edge of monovacancy defect can adsorb an incident hydrogen atom more easily but can not diffuse the gained energy as efficiently as in a perfect graphite sheet. These results are helpful for understanding the chemical erosion of carbon based materials and the ensuing tritium retention in fusion devices.
Photoemission stability of negative electronaffinity GaN phtocathode
Authors: Guo Xiang-Yang  , Chang Ben-Kang  , Wang Xiao-Hui  , Zhang Yi-Jun  , Yang Ming  ,   Department of Electronic Engineering and Optoelectronic Technology, Nanjing University of Science & Technology, Nanjing 210094, China
Published: December 2020

The spectral response and quantum yield curve of reflection mode GaN photocathode just after Cs, O activation and Cs reactivation was achieved by using the online multi-information measurement and evaluation system. Also the attenuation in photocurrent under the radiation of 300 nm light is measured every hour.The result indicates that GaN photcathdoe are much more stable than narrow band material. The photocurrent peak increased by 16.8% after Cs reactivation which demonstrates the reason of the QE attenuation is the Cs desorption on the Cs, O adlayer of surface. This can be explained by a double dipole layer model :Cs-O whose stability determines the stability of GaN photocathode.