bluuebunny/crossref_metadata_2025 huggingface dataset:
Plasma emission diagnostics for the optimization of deposition parameters in RF magnetron sputtering of GaP film
Authors: Li Yang-Ping  , Liu Zheng-Tang  ,   西北工业大学材料学院，西安  710072
Published: December 2020

GaP thick films were prepared on ZnS substrates by RF magnetron sputtering starting from a GaP target in an Ar atmosphere. Plasma emission diagnostics was employed to investigate the glow discharge during the deposition process. Only the emission lines of Ar atom appear and effects of the deposition parameters on the intensities of the emission lines were studied systematically. The deposition parameters were optimized through increasing the RF power and decreasing the working gas pressure of Ar simultaneously, with the intensity of the emission lines kept constant. And thus, stoichiometric GaP thick films with high IR transmission performance were deposited at an elevated deposition rate.
Investigation of Si film anode prepared by ion beam assisted deposition
Authors: Chen Li-Bao  , Yu Hong-Chun  , Xu Chun-Mei  , Wang Tai-Hong  ,   湖南大学微纳技术研究中心，长沙  410082
Published: December 2020

Si film anode was prepared by ion beam assisted deposition for Li ion batteries. The crystal structure, morphology and electrochemical performance of Si film were investigated in detail. The results show that the Si film is amorphous. The intercalation/deintercalation voltages of the Si film were at 0.03V and 0.16 V as well as 0.34 V and 0.49 V. The Si film exhibits high specific capacity and efficiency, which are 3134.4 mAh/g and 87.1％ in the first cycle, respectively. Furthermore, the Si film shows superior cycle performance. The capacity retention is 92.2% after 200 cycles at 0.5C rate.
Optical constants of fluoride films in the DUV range
Authors: Xue Chun-Rong  , Yi Kui  , Qi Hong-Ji  , Shao Jian-Da  , Fan Zheng-Xiu  ,   (1)常熟理工学院江苏新型功能材料实验室，常熟  215500；中国科学院上海光学精密机械研究所，上海  201800；中国科学技术大学国家同步辐射实验室，合肥  230029; (2)中国科学院上海光学精密机械研究所，上海  201800
Published: December 2020

High-refractive-index materials such as LaF3, NdF3 and GdF3 and low-refractive-index materials such as MgF2, AlF3 and Na3AlF6 single thin films are deposited by a resistive-heating boat at different deposited rates and specific substrate temperatures on single crystal MgF2 substrate. Transmittances of all fluoride thin films are measured through commercial spectrometer in the ambient atmosphere. Optical constants of these films are determined by the envelope method and the factors effecting optical constants are studied. Result of this work may play an important role in the design and manufacture of cost-effective, mechanically and optically stable optical coatings for the VUV region.
A novel element of frequency selective surface with stable performance
Authors: Jia Hong-Yan  , Gao Jin-Song  , Feng Xiao-Guo  , Sun Lian-Chun  ,   (1)中国科学院长春光学精密机械与物理研究所，长春  130033; (2)中国科学院长春光学精密机械与物理研究所，长春  130033；中国科学院研究生院，北京  100049
Published: December 2020

Frequency selective surface (FSS) composed of a novel element is presented in this paper. The novel element is designed by adding L-shaped slots to the cross aperture at its four ends. By disconnecting the novel element，a corresponding disconnected element FSS is designed. Based on the spectral-domain approach，two FSS structures with the novel element are calculated and analyzed theoretically. The influence on the center frequency for changing angles of TE incidence，polarization of large angle incident waves and the pass band width in the operating frequency band are researched. With filming technology and lithography，two FSS samples are made. The tests are made in the microwave darkroom. The measured curve shows good agreement with the calculated curve. It is shown that the resonant frequency of both FSS structures are angle independent for TE incident waves or polarization independent for large angle incidence. Meanwhile，our disconnected element FSS structure has wider pass band with little change of the resonance frequency.
Damage of electron irradiation to the GaInP/GaAs/Ge triple-junction solar cell
Authors: Hu Jian-Min  , Wu Yi-Yong  , Qian Yong  , Yang De-Zhuang  , He Shi-Yu  ,   (1)哈尔滨工业大学，材料科学与工程学院，哈尔滨  150001; (2)哈尔滨工业大学，材料科学与工程学院，哈尔滨  150001；哈尔滨师范大学阿城学院，哈尔滨  150301; (3)上海空间电源研究所，上海  200233
Published: December 2020

Radiation damages of 1 Mev and 1.8 Mev electrons to the triple-junction GaInP/GaAs/Ge solar cell are investigated. The results indicate that electric properties of the GaInP/GaAs/Ge triple-junction solar cell, such as open-circuit voltage, short-circuit current and maximum power, decrease obviously as the irradiation fluence increases. Under the irradiation fluence of 1×1015cm-2 of 1 MeV electrons, the maximum power output is degraded by 17.7%. Under higher energy electron irradiation, the dark I-V characteristic shows that the changes in both the series and parallel connection resistance of the triple-junction cell are reasons causing the degradational of electrical properties. By the analysis of spectral response, the degradation in electric properties is primarily duc to the severe damage of the GaAs sub-cell. The damage of the sub-cell is associated closely with the obvious decrease in the collecting efficiency of light-generated carriers in the bottom of the base-zone. The key to improve the radiation resistance of the triple-junction GaInP/GaAs/Ge solar cell is to reduce the damage of the base-zone of GaAs sub-cell as much as possible.
The transmission of weak signal in one-way coupled Hodgkin-Huxley neural system
Authors: Liang Xiao-Bing  , Liu Xi-Shun  , Liu An-Zhi  , Wang Bo-Liang  ,   (1)国防科技大学电子科学与工程学院，长沙  410073; (2)厦门大学计算机科学系，厦门  361005
Published: December 2020

The study of signal transmission in neural models is helpful to investigate and model the transmission mechanism of biological neural systems, and realize the signal processing of cognition mechanism. We investigate the transmission of weak signals in a noisy one-way coupled Hodgkin-Huxley neural system. The results show that there is stochastic resonance and it helps to detect and transmit the signal. In addition, the coupling enables the signal transmission in the system. The efficiency of the signal transmission is increased with the increasing coupling strength. At some strength the firing of the elements will be in synchronization. What’s more, the optimal noise intensity of the receptor declines with the increase of the coupling strength, in the end will be equal to that of the driver. When the coupling strength is too high, the receptor will fire by itself. But the spikes will be suppressed by the increasing noise. It may be used to interpret the self action of neurons and the self adjusting in neural system. In addition, these results show that the noise and coupling are important to the transmission of weak signal in neural system. This study maybe helpful to interpret some phenomena in biological experiments.
Effects of channel noise on metabolic energy cost of action potentials
Authors: Wang Hui-Qiao  , Yu Lian-Chun  , Chen Yong  ,   兰州大学理论物理研究所，兰州  730000
Published: December 2020

We study the metabolic energy cost of action potential in neuron for various membrane sizes and at different temperatures. Using the occupation number method to model stochastic Hodgkin-Huxley neuron, we found that there exists a minimal metabolic energy cost near the real size of the membrane at room temperature.
Investigation on human ear’s capability for identifing non-speech objects
Authors: Chen Ke-An  , Wang Na  , Wang Jin-Chang  ,   西北工业大学航海学院环境工程系，西安  710072
Published: December 2020

Investigation on human ears capability receives much attention in auditory science and target automatic recognition. In this paper, the relationship between auditory identification, nature of sound, training level and ambient noise are investigated by the test of subjective auditory capability approach. The test results are as follows: Human ears capability of identification is dependent on sound spectral structure and it will be better when the signal is of harmonic nature and in steady-state. The identification accuracy, being closely related with sound characteristic, can be improved by training of juries. The auditory identification capability under noise environment lies on sound spectral structure.
Potential impacts of global warming on extreme warm month events in China
Authors: Wan Shi-Quan  , Wang Ling  , Feng Guo-Lin  , He Wen-Ping  , Wang Chan-Juan  , Zhou Guo-Hua  ,   (1)国家气候中心，北京  100081; (2)国家气候中心，北京  100081；扬州大学物理科学与技术学院，扬州  225002; (3)扬州市气象局，扬州  225009; (4)扬州市气象局，扬州  225009；兰州大学大气科学学院，兰州  730000
Published: December 2020

In this study the average monthly data anomalies of 1960-2007 for 740 stations in China were analyzed. This research uses EVT （extreme value theory） to explore the spatial EWME （extreme warm month events） properties in China. The effects of potentially explanatory factors - climate warming on the distribution of EWME are investigated using GPD model with parameters estimated via a spatial scheme. The results showed that: 1） The properties of EWME have strong spatial dependence. The EWME have smaller variability over Tibetan plateau and North China plain and the coastal area of South China, while the EWME have larger variability over North China. There are more EWME with higher quantile over Middle-lower Yangtze area than that over the other regions. 2） The stations have the return period of the 2002 EWME with 3-5 centigrade longer than 10 years, and some grids have the return period longer than 50 years for EWME with 5-7 centigrade. 3） It has a potential relationship between regional climate warming and the EWME over some of special region. The variability and high quantile of the EWME are affected obviously by climate warming over Tibetan plateau plain and North China plain and northeast China plain, namely over the regions between monsoons on and non-monsoons.
Studies on propagation of laser beam array with initial phase distributions in a turbulent atmosphere
Authors: Zheng Wei-Wei  , Wang Li-Qin  , Xu Jing-Ping  , Wang Li-Gang  ,   (1)浙江大学物理系光学研究所,杭州  310027; (2)浙江大学物理系光学研究所,杭州  310028; (3)浙江大学物理系光学研究所,杭州  310029; (4)浙江大学物理系光学研究所,杭州  310030
Published: December 2020

Based on the coherent superposition principle and the generalized Huygens-Fresnel diffraction integral, the properties of a radial beam array with definite initial phase distributions propagating through a turbulent atmosphere are analytically investigated. It is shown that, when the propagation distance is short, the output intensity distribution will gradually take on a spiral shape, which means an optical vortex. However, under the effect of the atmospheric turbulence, the output vortex property gradually disappears, and changes to a bright-cantered beam without vortex property. Furthermore, the weaker the atmospheric turbulence is, the longer distance the output optical vortex （the center-dark beam） can propagate over.
Study of intrinsic defects in ZnO varistor ceramics by dielectric spectroscopy
Authors: Li Sheng-Tao  , Cheng Peng-Fei  , Zhao-Lei  , Li Jian-Ying  ,   (1)西安工程大学理学院，西安  710048; (2)西安交通大学电力设备电气绝缘国家重点实验室，西安  710049
Published: December 2020

In this paper defect structure was investigated by dielectric response of pure ZnO ceramics，binary and multi-element ZnO-Bi2O3 based varistor ceramics with the help of broad band dielectric spectroscopy. It is found that no loss peak appears at room temperature in pure ZnO ceramics，while there is one and two loss peaks in the binary and multi-element ZnO-Bi2O3 based varistor ceramics，respectively. According to relaxation polarization theory and electronic relaxation theory，it is obtained that electronic relaxation process is equivalent to relaxation polarization in dielectric spectroscopy and the characteristic peak near 105Hz at room temperature arises from relaxation process of electrons trapped by oxygen vacancies and zinc interstitials. Based on the difference in the dependence of the two loss peaks on the temperature and the atmosphere of heat treatment，aging mechanism is explained as the desorption of oxygen.
Semi-super junction SiGe high voltage fast and soft recovery switching diodes
Authors: Ma Li  , Gao Yong  ,   (1)西安理工大学电子工程系，西安  710048; (2)西安理工大学应用物理系，西安  710048
Published: December 2020

Semi-super junction (S-SJ) is developed on the basis of the super junction (SJ) structure by adding BAL (bottom assist layer) in the base region. One should only adjust the depth and the doping concentration of the BAL in the S-SJ structure to obtain higher working voltages. At the same on resistance, the aspect ratio of p-column in the S-SJ structure is less than that in the super junction structure, which means simpler process of epitaxial growth and ion implantation, which is very effective in reducing the process difficulty and the manufacture cost. Because the band gap of SiGe material can be adjusted by changing the Gefraction and the epilayers strain, the carrier mobility is increased with the increasing Ge content, the manufacture process is compatible with Si process, and great importance has been gradually attached to the SiGe material. To meet the requirements of low forward conducting voltage drop, high breakdown voltage, minimum reverse leakage current, and fast and soft reverse recovery process for power diodes in high frequency power electronics circuits, a S-SJ SiGe diode with remarkable improvement in all these characteristics of present power diode is proposed by combining both merits of S-SJ structure and SiGe material in this paper.
Temperature characteristics of AlGaN/GaN MOS-HEMT with Al2O3 gate dielectric
Authors: Liu Lin-Jie  , Yue Yuan-Zheng  , Zhang Jin-Cheng  , Ma Xiao-Hua  , Dong Zuo-Dian  , Hao Yue  ,   西安电子科技大学，宽禁带半导体材料与器件重点实验室，西安  710071
Published: December 2020

A metal-oxide-semiconductor high-electron-mobility transistor (MOS-HEMT) with atomic layer deposition (ALD) of 10nm Al2O3 gate dielectric is manufactured. The superiorities in saturation current and leakage current of the novel MOS-HEMT device are verified by comparison of the MOS-HEMT with traditional MES-HEMT devices at room temperature. The statistical analysis of the features of temperature variation of the device characteristics in the 30—180℃ range, which shows the distinction in degration degree by temperature on the two kinds of devices, is also illustrated. The conclusion that the device saturation current and the transconductance degradations are mainly caused by transport characteristic degradation is reached at. Thus, the conclusion can be drawn that all statistical and analytical results witness the significant role played by the reduced surface states in the surface of the AlGaN in optimizing the characteristics of the device.
Energy level-splitting of ground state in spinor Bose-Einstein condensate with large number of atoms
Authors: Xu Yan  , Jia Duo-Je  , Li Zhao-Xin  , Hou Feng-Chao  , Tan Lei  , Zhang Lu-Yin  ,   (1)兰州大学理论物理研究所,兰州  730000; (2)山东科技大学理学院，青岛  266510; (3)西北师范大学理论物理研究所，兰州  730030
Published: December 2020

We study the mode deviation effect of a spin-1 Bose-Einstein condensate with large number of atoms in optical trap beyond the single-mode approximation. Based on the effective Hamiltonian with nondegenerate level of the collective spin states, we get the mode deviation factor and explicitly calculate the level splitting energy as function of the atom number N.
Study on switching current of periodic poling LiNbO3 by applying external field
Authors: Chen Jian-Hua  , Qu Shao-Bo  , Wei Xiao-Yong  , Xu Zhuo  , Zhu Lin-Hu  ,   (1)空军工程大学工程学院,西安  710038；西安交通大学电子陶瓷与器件教育部重点实验室,西安  710049; (2)空军工程大学理学院,西安  710051; (3)西安交通大学电子陶瓷与器件教育部重点实验室,西安  710049; (4)西安交通大学电子陶瓷与器件教育部重点实验室,西安  710049；空军工程大学理学院,西安  710051
Published: December 2020

Periodically poled LiNbO3 was prepared by applying external field. Through a comparison study on switching currents of different sized PPLN, a new method of determining the nucleation time and the velocity of domain tip propagation toward the opposite face of the crystal was proposed. According to this method, a conclusion could be drawn that the nucleation time is 80ns and the tip velocity of switching domain is 0.1667m/s, when the external field is 25.1kV/mm, 50ms square wave pulse.
Reflectivity of semi-infinite one-dimensional photonic crystal composed of alternate layers of ordinary material and negative refraction material
Authors: Wang Zhen-De  , Liu Nian-Hua  ,   (1)南昌大学物理系，南昌  330031; (2)南昌大学物理系，南昌  330031；南昌大学高等研究院，南昌  330031
Published: December 2020

The reflection on the semi-infinite periodic one-dimensional photonic crystal composed of alternate layers of ordinary material and negative refraction material is investigated. We find that the reflectivity is exactly equal to 1 in the forbidden frequency gap, and in the pass band, it averages out the rapid fluctuation of reflection of the finite structure. When the optical thickness of both ordinary material and negative refraction material are in opposite sign, there will be a zero-n band gap. We analytically prove that the zero-n band gap is insensitive to incident angle and polarization. It is also anticipated that the zero-n band gap is invariant with the scaling of lattice constant.
High temperature Raman spectra and micro-structure of KTN crystal and melt
Authors: Zhou Wen-Ping  , Wan Song-Ming  , Yin Shao-Tang  , Zhang Qing-Li  , You Jing-Lin  , Wang Yuan-Yuan  ,   (1)上海市钢铁冶金新技术开发应用重点实验室，上海大学，上海  200072; (2)中国科学院安徽光学精密机械研究所，合肥  230031
Published: December 2020

The high temperature Raman spectra of KTN crystal and melt were studied. The structures of KTN crystal and melt were analyzed. The rule of structure change of KTN crystal with increasing temperature was analyzed. The results show that the peaks of spectra move to the lower wavelength and broaden by different degrees. The intensities of spectra peaks decrease, too. Raman peaks at 538, 585, 835, 868 and 875cm-1 were analyzed in detail. Phase transition from tetragonal to cubic was observed and explained. In high temperalure KTN melt, the ［Ta/NbO6］ octahedron entities disappeared. Meanwhile, there were many Ta/Nb O double bonds in the ［Ta/NbO3］- entities. It showed that there were ［Ta/NbO3］- growth unities in KTN melts.
Thermal stability of structure and properties of CHx doped SiCOH low dielectric constant films
Authors: Du Jie  , Ye Chao  , Yu Xiao-Zhu  , Zhang Hai-Yan  , Ning Zhao-Yuan  ,   (1)上海交通大学物理系，上海  200030; (2)苏州大学物理科学与技术学院，江苏省薄膜材料实验室，苏州  215006
Published: December 2020

This paper investigates the effect of vacuum thermal treatment on current-voltage (I-V) and capacitance-voltage (C-V) characteristics, hydrophobic properties and microstructure of CH4 doped SiCOH low dielectric constant films deposited by decamethylcyclopentasiloxane (D5) electron cyclotron resonance plasma. The results show that the desorption of thermally unstable CHx groups during the heat treatment can lead to the decrease of leakage current, the variation of SiCOH/Si interface state and the decrease of surface roughness. However, the desorption of CHx groups also leads to the deterioration of hydrophobic property.
RE-TM antiferromagnetic coupling and laser induced ultrafast magnetization reversal dynamics in GdFeCo magneto-optical films
Authors: Gao Rui-Xin  , Xu Zhen  , Chen Da-Xin  , Xu Chu-Dong  , Chen Zhi-Feng  , Liu Xiao-Dong  , Zhou Shi-Ming  , Lai Tian-Shu  ,   (1)光电材料与技术国家重点实验室，物理科学与工程技术学院，中山大学，广州  510275; (2)先进光子材料与器件国家重点实验室，物理系，复旦大学，上海  200433
Published: December 2020

The RE-TM antiferromagnetic coupling behavior and magnetization reversal dynamics in passing through the fermimagnetic compensation temperature (Tm) due to laser heating of GeFeCo films are investigated using femtosecond time-resolved pump-probe Kerr spectroscopy. Owing to sample temperature passing through Tm and hence the exchange of net magnetic moment carriers, an abnormal hysteresis loop is observed. The saturation magnetization difference between magnetization states above and below coercive field is found under a same direction of magnetic field, which reveals the incomplete rigid coupling between RE and TM sub-lattices in GdFeCo. A complete ultrafast magnetization reversal and recovery dynamic process is experimentally observed at the saturation magnetic bias on the sample with Al heat sink layer. Besides, by comparing magnetization reversal at saturation magnetic bias with magnetization recovery at remanence, it was found that the magnetic field applied externally does not affect the rate of domain nucleation and growth, but only their magnetization direction.
Synthesis of nanorod GdPO4:Eu3+ phosphor and its photoluminescent properties
Authors: Tong Jin-Gang  , Wu Chun-Fang  , Wang Yu-Hua  , Chen Zuo-Hui  ,   (1)兰州大学物理科学与技术学院,兰州  730000; (2)兰州大学物理科学与技术学院,兰州  730000；兰州大学磁学与磁性材料教育部重点实验室,兰州  730000
Published: December 2020

Nanorod GdPO4:Eu3+ phosphor was prepared by solovothermal reaction and the phosphorus source and the pH value of the solution were important to the final product. Photoluminescence properties of nanorod GdPO4:Eu3+ phosphor was compared with bulk GdPO4:Eu3+ phosphor. The luminescence colour purity of nanorod GdPO4:Eu3+ phosphor was better than that of the bulk GdPO4:Eu3+ phosphor under 147nm excitation. The host absorption band and Eu-O charge transfer band of nanorod GdPO4:Eu3+ phosphor were blue shifted compared with the bulk GdPO4:Eu3+ phosphor.
Improving the quantum well properties with n-type InGaN/GaN superlattices layer
Authors: Xing Yan-Hui  , Deng Jun  , Han Jun  , Li Jian-Jun  , Shen Guang-Di  ,   北京工业大学电子信息与控制工程学院，北京  100124
Published: December 2020

InGaN/GaN quantum wells have been grown by metal-organic chemical vapor deposition. InGaN/GaN quantum well with n-type InGaN/GaN thin layer or InGaN/GaN superlattice layer were studied. By introducing n-type InGaN/GaN thin layer or InGaN/GaN superlattice layer, the strain in quantum well active area was released, the surface morphology was improved and the density of V-type defect was redued. It was also found that the multiple quantum well photoluminescence intensity and the radiation efficiency of light emitting diodes were both higher than that of the structure without InGaN/GaN superlattice layer.
Polarized blue polymer light-emitting diodes utilizing rubbed hole injection layers
Authors: Zhu De-Xi  , Zhen Hong-Yu  , Ye Hui  , Liu Xu  ,   浙江大学现代光学仪器国家重点实验室，杭州  310027
Published: December 2020

Polarized blue electroluminescence has been achieved from the oriented poly (9, 9-dioctylfluorene) (PFO) film on a rubbed hole injection layer poly(3,4-ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS) at the CIE coordinates of (0.20, 0.21). Polarized absorption and photoluminescence spectra reveal that the dichroism of the PFO film is influenced by the rubbing strength of the alignment layer, the annealing temperature, and annealing time, among which the annealing temperature is the most significant factor. An electroluminescence polarization ratio of about 3 is achieved when the rubbing depth is 50μm, the annealing temperature is 200℃ and the annealing time is 30 min.
Conical bubble sonoluminescence in organic solution
Authors: Ha Jing  , He Shou-Jie  , Duan Ping-Guang  , Li Xia  , Han Yu-Hong  , Wang Long  ,   (1)河北大学物理科学与技术学院，保定  071002; (2)河北农业大学理学院，保定  071001
Published: December 2020

Based on the U-tube, one new type of sonoluminescence apparatus —the conical bubble sonoluminescence straight tube has been set up. Using the apparatus, the ultrabright cavitation luminescence was obtained and the spectra were measured. Results show that the spectra consist in a broad background ranging from the ultraviolet region to the visible region, on which five clear sequences of Swan bands and three sequences of B2Σ+→X2Σ+ transition of CN are superimposed. A band assigned to the A2Δ→X2Π transition of CH has also been measured. Specially, the vibrational structures of Swan bands could be resolved clearly. In addition, the achieved molecular vibrational temperature is estimated to be about 5100±200 K. Finally, the chemical reactions in the sonoluminescence are discussed, which shows the excitence of chemiluminescence in sonoluminescence from organic solution.
Third-order nonlinear optical properties of CuO film
Authors: Chen Ai-Ping  , Long Hua  , Wang Kai  , Yang Guang  , Fu Ming  , Li Yu-Hua  , Lu Pei-Xiang  ,   武汉光电国家实验室,华中科技大学,武汉  430074
Published: December 2020

Single-phase CuO thin films have been obtained on Si(100) and quartz substrates using pulsed laser deposition technique. The structure, surface image, optical transmittance and reflectance of the films were characterized by X-ray diffraction, Raman spectroscopy, scanning electron microscopy and UV-vis spectroscopy. The SEM image demonstrates that the grain size is about 45nm. The third-order optical nonlinearities in CuO films were investigated by Z-scan method using a femtosecond laser (800nm, 50fs). The results show that CuO films have ultrafast nonlinear optical response and large optical nonlinearity with the real and imaginary parts of third-order nonlinear susceptibility, χ(3), being -7.88×10-11 esu and -2.13×10-11 esu, respectively, indicating CuO thin films are potential materials for applications in nonlinear optical devices.
The effects of melt spinning process on microstructure and thermoelectric properties of Zn-doped type-I clathrates
Authors: Cao Wei-Qiang  , Deng Shu-Kang  , Tang Xin-Feng  , Li Peng  ,   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

The single-phase Zn-doped type-I Ba8Ga12Zn2Ge32 clathrates have been prepared by a novel melt spinning (MS) technique combined with spark plasma sintering (SPS) method, and the effects of melt spinning process on their microstructure and thermoelectric transport properties have been investigated. The results show that the free surface of ribbon obtained by MS consists of cubic grains with the size of 0.3—1.0μm, and after SPS a highly dense bulk material with lots of fine-layered structure has been obtained. Compared with the bulk Ba8Ga12Zn2Ge32 material prepared by melting method combined with SPS (MM+SPS sample), the bulk Ba8Ga12Zn2Ge32 material obtained by melting method combined with MS and SPS (MM+MS+SPS sample) has higher carrier concentration and lower carrier mobility at room temperature. Furthermore, the MS process leads to a slight decrease of electrical conductivity, somewhat increase of Seebeck coefficient, as a well as a remarkable decrease of lattice thermal conductivity for bulk Ba8Ga12Zn2Ge32 clathrates in the testing temperature range of 300—900K. At 900K, the latticethermal conductivities of MM+SPS sample and MM+MS+SPS sample are 1.06 and 0.42W/mK respectively. As a result, the maximum dimensionless figure of merit ZT of 0.90 is obtained at 900K for the MM+MS+SPS sample. Compared with that of MM+SPS sample, it increases by 75% at the same temperature.
Microscopic phase field simulation for the evolution of antisite defect of L12 structure and D022 structure in Ni75Al5.3V19.7 alloy
Authors: Zhang Jing  , Chen Zheng  , Wang Yong-Xin  , Lu Yan-Li  , Huo Jin-Liang  , Zhen Hui-Hui  , Zhao Yan  ,   西北工业大学材料学院,西安  710072
Published: December 2020

The antisite defect for L12-structure Ni3Al and D022-structure Ni3V of Ni75Al5.3V19.7 alloy is studied by microscopic phase field method in this paper. The results show that the concentration of antisite defects AlNi，VNi and NiAl for L12 structure，VNi, AlNi,Niv and AlV for D022 structure all decrease with precipitate process and reach to equilibrium values at the early stage of precipitation respectively. With the elapse of time, the two structures grow up while the concentrations of antisite defects always keep unchanged. The concentrations of equilibrium state antisite defects AlNi and VNi for L12 structure α site, VNi and AlNi for D022 structure α site are of the 10-2 order, and antisite defect NiAl for L12 structure β site, NiV for D022 structure β site are of 10-1 order, the two defects being the main antisite defects for the L12 and D022 structures. The addition element has a great site-preference for a certain ordered phase, V atom prefers to occupy L12 structure β site while Al atom prefers to occupy D022 structure α site.
The resistivity evolution with temperature of 7050 aluminium alloy by different casting methods
Authors: Fan Fei  , Ban Chun-Yan  , Wang Yang  , Ba Qi-Xian  , Cui Jian-Zhong  ,   东北大学材料电磁过程研究教育部重点实验室，沈阳  110004
Published: December 2020

The resistivity-temperature curve of 7050 aluminium alloy prepared by different casting methods (DC and LFEC) has been measured with D.C. four-probe method. By analysing the curve, it was found that a change occurred to the slope at 250℃ when the samples were heated, and the resistivity of LFEC sample changed with temperature more quickly than that of DC. Both the solidus and liquidus temperatures of LFEC samples were higher than those of DC samples during the process of temperature rise from room temperature to 900℃. However, the resistivity of DC samples increased remarkably when the temperature was kept at 900℃ and before it was decreased to 600℃. With the help of microstructure observation, the characteristics and phenomenon of the resistivity evolution with temperature were studied.
The reconstructing of soot agglomerates in propene ozonolysis and photooxidation systems
Authors: Lü Zi-Feng  , Hao Ji-Ming  , Li Jun-Hua  , Wu Shan  ,   清华大学环境科学与工程系，北京  100084
Published: December 2020

The soot in the atmosphere exhibits irregular fractal agglomerate structure. In this study, the reconstruction of agglomerate structure is observed for soot generated by spark discharge in both propene ozonolysis and photooxidation systems. This process makes the agglomerate soot more compact, and is possibly caused by the peroxy radicals and hydroxyl radicals generated from propene oxidation. The result furthers our understanding of the atmospheric aging process of soot agglomerate. Since the reconstruction directly changes the size distribution of soot, it may induce important changes to the soot's physical and chemical properties in the atmosphere.
The performance of solar cell based on the blend of MEH-PPV∶TiO2
Authors: Yu Huang-Zhong  , Peng Jun-Biao  , Liu Jin-Cheng  ,   (1)华南理工大学高分子光电材料及器件研究所,特种功能材料教育部重点实验室，广州  510640; (2)华南理工大学物理系，广州  510640；华南理工大学高分子光电材料及器件研究所,特种功能材料教育部重点实验室，广州  510640
Published: December 2020

The solar cells based on the blend of MEH-PPV(poly(2-methoxy-5-(2′-ethylhexoxy)- 1,4-phenylene vinylene) as donor and TiO2 nanorods as acceptor were fabricated. We analyzed the cause of performance change of the device in detail by the ultraviolet-visible absorption spectroscopy(UV-vis), photoluminescence spectroscopy(PL), the current density-voltage(J-V) curve. When TiO2 nanorods are dispersed in a polymer matrix, the performance of the device is greatly enhanced. The highest efficiency is achieved for the 1∶3 (MEH-PPV: TiO2 nanorods) weight ratio composition. We get an open circuit voltage of 0.7V, short circuit current density of 0.41 mA/cm2 and fill factor of 31.8% under air-mass 1.5 solar simulator illumination, yielding a 0.091% power conversion efficiency (PCE)，which is a nearly 60 times enhancement over the PCE of the device based on the MEH-PPV as active layer. The device PCE is further increased twofold by refluxing in phenthiol.
Evolution of average intensity distribution and angular spread of partially coherent Hermite-sinh-Gaussian beams propagating through turbulent atmosphere
Authors: Li Jin-Hong  , Yang Ai-Lin  , Lü Bai-Da  ,   四川大学激光物理与化学研究所，成都  610064
Published: December 2020

The analytical expressions for the average intensity and angular spread of partially coherent Hermite-sinh-Gaussian (H-ShG) beams propagating through turbulent atmosphere are derived and used to study the evolution of average intensity distribution and angular spread of partially coherent H-ShG beams in turbulence. It is shown that an increase of the refraction index structure constant C2n and a decrease of the spatial correlation length σ0 accelerate the evolution process. The relative angular spread is introduced to quantitatively describe the resistance of a beam to turbulence. The smaller the spatial correlation length σ0, the waist width w0, the Sh-part parameter Ω0, and the larger the beam orders m, n, the less the angular spread of partially coherent H-ShG beams is affected by turbulence.
Approximate analytic solution to a class of generalized Canard systems
Authors: Mo Jia-Qi  ,   安徽师范大学数学系,芜湖  241000；上海高校计算科学E-研究院上海交通大学研究所,上海  200240
Published: December 2020

Using the variational iteration theory, we obtain the approximations to the solution of the generalized Canard systems. Firstly, a set of functional is introduced. Then the iteration expressions of solving the original equation are constructed. Finally, the analytic expressions of the Canard solution are obtained.
Quesne-like ring-shaped spherical harmonic oscillator potential and pseudospin symmetry
Authors: Zhang Min-Cang  ,   陕西师范大学物理学与信息技术学院，西安  710062
Published: December 2020

A Quesne-like ring-shaped spherical harmonic oscillator potential is put foword and studied for spin 1/2 particles based on the Dirac equation， the Dirac Hamiltonian contains a scalar and a vector Quesne-like ring-shaped harmonic oscillator potentials. Setting Σ＝S(r)+V(r)=0,we obtain the bound state solutions and eigenenergies with the two-component approach. The result shows the pseudospin symmetry exists in the Quesne-like ring-shaped harmonic oscillator potential. The general properties of both the ring-shaped spherical harmonic oscillator potential and the ring-shaped non-spherical harmonic oscillator potential are discussed.
A single photon source based on entangled photon pairs
Authors: Ma Hai-Qiang  , Wang Su-Mei  , Wu Ling-An  ,   (1)北京理工大学车辆与工程学院，北京  100081; (2)北京邮电大学理学院,北京  100876;中国科学院物理研究所光物理开放实验室，北京  100190; (3)中国科学院物理研究所光物理开放实验室，北京  100190
Published: December 2020

A single-photon source scheme based on entangled photon pairs from parametric down conversion is proposed, by means of which the single-photon quality is greatly improved, i.e. the multi-photon-pulse probability is reduced 100 times compared with that of an ordinary attenuated weak light source. The optical set-up and data acquisition are explained in detail. Experimental results show the good potential of this system for practical applications.
Nonlinear Landau-Zener tunneling in two-dimensional photonic lattices
Authors: Wang Sha  , Yang Zhi-An  ,   济南大学理学院，济南  250022
Published: December 2020

Nonlinear Landau-Zener tunneling in two-dimensional photonic lattices of Kerr nonlinearity media is investigated. We first derive the nonlinear three-level Landau-Zener model in photonic lattices for the case of hexagonal symmetry, and then simplify this model to a nonlinear two-level Landau-Zener model under a certain initial condition. For the three-level tunneling model, we calculate the tunneling probability numerically and study its changing rules under the specific initial condition.
Multi-order corrections of variational-integral perturbation for heavy quarkonium
Authors: Zhao Yun-Hui  , Hai Wen-Hua  , Zhu Qian-Quan  ,   (1)湖南师范大学物理系，长沙  410081; (2)湖南师范大学物理系，长沙  410081；邵阳学院物理系，邵阳  422000
Published: December 2020

We employ the improved variational-perturbation method based on integral equation (variational-integral perturbation method) to solve the heavy quarkonium in the 2S state. Setting the mother Hamiltonian including variational parameter as the zero-order Hamiltonian and choosing the exact solution of the mother Hamiltonian system as the trial wave function, we obtain the multi-order corrected wave functions consisting of a few terms and calculate the multi-order energy corrections. The corrected wave functions are quadratically integrable and the energy corrections are in good agreement with the exact data. The boundedness and convergence of the perturbation series solution are also verified. The results show that the variational-integral perturbation method can not only raise precision of the result but also keep convergence of the wave function.
Predication of multivariable chaotic time series based on maximal Lyapunov exponent
Authors: Zhang Yong  , Guan Wei  ,   北京交通大学系统工程与控制研究所，北京  100044
Published: December 2020

A method for prediction of multivariable chaotic time series through selecting many neighboring reconstructed vectors is proposed with reference to the method for prediction of single-variable chaotic time series based on maximal Lyapunov exponent. The new method is used to forecast the chaotic time series of two Rssler equations coupled system, Rssler equation and Hyper Rssler equations coupled system for onestep and multistep. Results show that the algorithm can forecast multivariable chaotic time series precisely and has strong anti-chirp ability. The relation between the result and the number of neighbor points is discussed.
Projective synchronization of Chua chaotic system based on fuzzy observer
Authors: Meng Juan  , Wang Xing-Yuan  ,   大连理工大学电子与信息工程学院，大连  116024
Published: December 2020

The generalized projective synchronization of Chua chaotic system is investigated. A new fuzzy observer is designed based on the Takagi-Sugeno (T-S) fuzzy model. According to the Lyapunov stability theory, it is verified that the proposed scheme is feasible and globally stable. Numerical simulations further demonstrate that the projective synchronization of Chua circuit can be achieved by using the proposed scheme. The designed procedure is simple, and the method can be adapted to other chaotic systems.
Response to bounded noise excitation of stochastic Mathieu-Duffing system with time delay state feedback
Authors: Xing Zhen-Ci  , Xu Wei  , Rong Hai-Wu  , Wang Bao-Yan  ,   (1)佛山大学数学系，佛山  528000; (2)西北工业大学应用数学系，西安  710072
Published: December 2020

We investigate the principal parametric resonance of Mathieu-Duffing Equation under a narrow-band random excitation with time delay feedback. The method of multiple scales is used to determine the equations of modulation of amplitude and phase. The bifurcation of the system is discussed. We find that the bifurcation can be influenced by the detuning parameter, time delay, and the intensity of the non-linear term, and an appropriate choice of these parameters can change the response of bifurcation. In addition the stability of nontrivial solution is studied. The nontrivial solution of necessary and sufficient condition for stability is obtained. Moreover, we find that when the bandwidth of the random excitation is smaller, the multi-solution phenomenon still exists, and bifurcation and jumping phenomenon will occur. Theoretical analysis is verified by numerical results.
One-dimensional cellular automaton model of traffic flow considering drivers’ features
Authors: Peng Li-Juan  , Kang Rui  ,   四川大学计算机学院图形图像研究所，成都  610064
Published: December 2020

Based on the WWH model and SDNaSch model for one-dimensional cellular automaton traffic flow, a Driver-SDNaSch model considering the drivers′ features is established. In this model, drivers are classified into such three types as aggressive, cautious and neutral, and their states are updated following their respective evolution rules, which are made according to the different driving features of these three types. In addition, the safe deceleration probability is introduced when considering the condition of having a stationary vehicle ahead. By using the computer numerical simulation of the Driver-SDNaSch model, the velocity-density and flow-density diagrams of the mixed traffic flow, whose features are also analysed and discussed, with the three types of drivers in different proportions, are presented. The Driver-SDNaSch model, compared with the NaSch model and SDNaSch model, is believed to further reduce the traffic jams so as to increase the traffic capacity.
Degradation model of the optical properties of the thermal control coatings
Authors: Shen Zi-Cai  , Kong Wei-Jin  , Feng Wei-Quan  , Ding Yi-Gang  , Liu Yu-Ming  , Zheng Hui-Qi  , Zhao Xue  , Zhao Chun-Qing  ,   (1)北京卫星环境工程研究所，北京  100094; (2)青岛大学物理科学学院，青岛  266071
Published: December 2020

On the basis of experimental results，the degradation model of the optical properties of thermal control coatings due to space environment interaction are proposed. The optical properties of thermal control coatings prepared by complex refractive index materials are analyzed by using the concept of graded index，and the expressions of the changed optical properties of the coatings are given. Applications of the degradation model are also discussed.
Influence of incidence channel condition on isospin fractionation ratio based on the revised isospin-dependent quantum molecular dynamics
Authors: Guo Wen-Jun  , Sun Chang-An  , Liu Jian-Ye  ,   (1)上海理工大学理学院，上海  200093; (2)中国科学院近代物理研究所，兰州  730000；兰州重离子加速器国家实验室原子核理论中心，兰州  730000
Published: December 2020

Isospin degree of freedom is introduced in Skyrme potential and momentum dependent interaction to obtain the revised isospin dependent quantum molecular dynamics. The isospin effect of isospin fractionation ratio is studied for different beam energies and different colliding systems based on the revised isospin dependent quantum molecular dynamics. It is found that the isospin effect of isospin fractionation ratios is important for different incident channel conditions，for example，the isospin fractionation ratios for different incident channel conditions are reduced after the isospin degree of freedom in Skyrme potential and momentum dependent interaction are included. However, the isospin fractionation ratio is also sensitive to symmetry potential. In this case it is also a good probe for extracting information on the symmetry potential in heavy ion collisions.
Theoretical study of the adsorption of water molecule on (TiO2)n(n=3—6) clusters
Authors: Chen Hong-Shan  , Meng Fan-Shun  , Li Xiang-Fu  , Zhang Su-Ling  ,   西北师范大学物理与电子工程学院，兰州  730070
Published: December 2020

Possible adsorption structures of H2O on (TiO2)n(n=3—6) clusters were studied by using genetic algorithm combined with empirical potential function. The structures were further optimized using DFT method B3LYP/6-31G**. The results show that H2O molecule is adsorbed on TiO2 clusters through the attachment of oxygen atom to the titanium atom with lower coordination number. Molecular orbitals show that the bond between water and cluster is formed mainly by the 3s3p orbitals of titanium，the orbitals of H2O keep the basic features unchanged but are more delocalized after adsorption. Combined with population analysis and calculation of vibration frequencies，the results show that the O—H bond becomes weaker after H2O is adsorbed on TiO2 clusters.
Floquet mode analysis on the resonance behavior of metamaterials
Authors: Yang Rui  , Xie Yong-Jun  , Li Xiao-Feng  , Jiang Jun  , Wang Yuan-Yuan  , Wang Rui  ,   西安电子科技大学天线与微波技术国家重点实验室，西安  710071
Published: December 2020

The field distribution over a split ring resonator is expanded into Floquet modes，revealing the fact that the evanescent floquet modes actually lead to the metamaterial resonance behavior. Transmission through metamaterials is examined for arbitrary incident wave. It is shown that the resonance happens in the transmitted modes with the same polarization as that of the wave incident in the main plane. The electric and the magnetic resonances vary with the incidence angle. For the wave from other incident planes，the TE- and TM- Floquet modes will share the resonance.
The high-frequency method for scattering from the wedges of complex conductive targets in half space
Authors: Li Xiao-Feng  , Xie Yong-Jun  , Fan Jun  , Wang Yuan-Yuan  ,   西安电子科技大学天线与微波技术国家重点实验室，西安  710071
Published: December 2020

The high-frequency method for solving the scattering from the wedges of conductive targets with electrically large size in half space is presented in this paper. To take into account of the influence of environment，the half-space equivalent edge current method is deduced by introducing the half-space Greens function into the equivalent edge current method. Combined with the graphical-electromagnetic computing method，the shadow regions are eliminated quickly and the edge pixel parameters are obtained by reading the edge pixels. Meanwhile，we also make use of the half-space physical optical method to treat the complex targets，and then the radar cross section of the complex targets can be exactly calculated in half space. The numerical results show that this method is efficient and accurate.
Theoretical analysis of second-harmonic conversion efficiency in negative-index materials
Authors: Zhou Cheng  , Gao Yan-Xia  , Wang Pei-Ji  , Zhang Zhong  , Li Ping  ,   (1)济南大学理学院，济南  250022; (2)山东财政学院统计与数理学院，济南  250014
Published: December 2020

For negative-index materials(NIM) of second-harmonic wave(SHW) and positive-index materials of fundamental frequency wave(FFW)，the equations of the coupled wave was deduced，taking account of absorption coefficient，walk-off effect，phase mismatching capacity and the approximation of slow-varying amplitudes of the plane wave. On the basis of the equations，a formulation of SHW conversion efficiency was obtained in condition of small signal approximation for FFW. Through numerical simulation, the effects of phase mismatching capacity，walk-off angle and absorption coefficient of SHW on the conversion efficiency of SHW were scrutinized respectively. The maximum conversion efficiency of SHW was realized via increasing the length of NIM，that is，there exists an optimum length of NIM; however, the conversion efficiency of SHW shows an evidencet periodic evolution and the maximum conversion efficiency always diminishes. The conversion efficiency decreases with the increases of the phase mismatching capacity and the absorption coefficient. The influence of walk-off effect is not evident so that it may be neglected with respect to the conversion efficiency of SHW. This study provides a basis for investigating nonlinear theory of negative-index materials.
Influence of reflection of the output port on beam-wave interaction in gyrotron traveling wave amplifier
Authors: Sun Hai-Yan  , Jiao Chong-Qing  , Luo Ji-Run  ,   (1)中国科学院电子学研究所，北京  100190; (2)中国科学院电子学研究所，北京  100190；中国科学院研究生院，北京  100049
Published: December 2020

Based on the nonlinear self-consistent theory of gyrotron traveling wave amplifier (gyro-TWA)，the influence of the reflection from the tapering output port on the beam-wave interaction in the gyro-TWA is studied. The simulation results show that the amplitude and phase of the reflection coefficient resulting from the variation of the tapering angle at the output port and the beam-wave interaction length have great effect on the beam-wave interaction for a Ka band TE01 gyro-TWA. Reasonably selecting the tapering angle at the output port may increase the beam-interaction frequency bandwidth with a relatively short beam-wave interaction length while keeping the saturated output power of the gyro-TWA at almost the same level.
Photoluminescence and magnetic properties of cobalt doped SnO2 nano-powder
Authors: Liu Chun-Ming  , Fang Li-Mei  , Zu Xiao-Tao  ,   电子科技大学应用物理系，成都  610054
Published: December 2020

The influence of cobalt dopant on the photoluminescence and magnetic properties of SnO2 nano-powder is studied in detail. The cobalt dopant has little influence on the photoluminescence peaks' positions. However，the intensity ratio of ultra-violet to blue emission band is reduced with the increase of cobalt doping. The ferromagnetism is absolutely absent when the cobalt dopant level reaches 0.02. The magnetic interaction mechanism is discussed. Due to the non-uniform distribution of doping，and the coupling between the polarized spin on defects and the dopants，the anti-ferromagnetic interaction destroys the ferromagnetism.