bluuebunny/crossref_metadata_2025 huggingface dataset:
Molecular dynamics simulation on mechanical properties of gold nanotubes
Authors: Su Jin-Fang  , Song Hai-Yang  , An Min-Rong  ,   School of Science, Xi’an University of Posts and Telecommunications, Xi’an 710061, China
Published: December 2020

The tensile and compressive mechanical properties of gold nanotubes in different crystal orientations as well as the tensile mechanical properties of the same thinkness of gold nanotubes at different radius. are investigated using the molecular dynamics simulation method. In the simulation, we select embedded atom method as the interatomic potential function. The result shows that mechanical properties in the tensile and compressive process in different crystallographic orientations are dramatically different from each other, where the yield strength of the direction is the highest and the yield strength and the Young's modulus in the direction are less than in the and crystal orientation. The yield strength has no major changes when the radius is less than 3.0 nm, but it obviously decreases with the increase of the radius when the radius is larger than 3.0 nm.
X-ray spectrum emitted by the impact of 152Eu20+ of near Bohn velocity on Au surface
Authors: Liang Chang-Hui  , Zhang Xiao-An  , Li Yao-Zong  , Zhao Yong-Tao  , Mei Ce-Xiang  , Cheng Rui  , Zhou Xian-Ming  , Lei Yu  , Wang Xing  , Sun Yuan-Bo  , Xiao Guo-Qing  ,   Ion Beam and Optical Physical Joint Laboratory of Xianyang Normal University and Institute of Modern Physics Chinese Academy of Sciences,Xianyang 712000, China;,   Institute of Modern Physics Chinese Academy of Sciences, Lanzhou 730000, China
Published: December 2020

The characteristic X-ray spectra produced by the impact of highly charged ions of 152Eu20+ with energies from 2.0 to 6.0 MeV on Au surface are measured. It is found that highly charged ions could excite both the characteristic X-ray spectra of Mζ, Mα and Mδ of Au and the characteristic X-ray spectra of Mα of Eu. The total X-ray yield increases with the ion kinetic energy increasing. The total production cross section of Au induced by Eu20+ is measured and compared with those obtained from the binary encounter approximation, plane-wave-Born approximation, and the energy-loss Coulomb deflection perturbed stationary state relativistic theoretical models.
Ab initio calculation on the potential energy curves and spectroscopic properties of the low-lying excited states of BCl
Authors: Yu Kun  , Zhang Xiao-Mei  , Liu Yu-Fang  ,   Department of Physics, Xingyi Normal University for Nationalities, Xingyi 562400, China;,   College of Physics and Information Engineering, Henan Normal University, Xinxiang 453007, China
Published: December 2020

The high level quantum chemistry ab initio multi-reference configuration interaction method with reasonably large aug-cc-pVQZ basis sets is used to calculate the potential energy curves of 14 -S states of BCl+ radical correlated to the dissociation limit B+(1Sg)+Cl(2Pu) and B(2Pu) +Cl+(3Pg). In order to get the better potential energy curves, the Davidson correction and scalar relativistic effect are taken into consideration. The spin-orbit interaction is first considered, which makes the lowest 4 -S states split to 7 states. The calculational results show that the avoided crossing rule exists between the states of the same symmetry. The analyses of the electronic structures of -S states determine the electronic transition of each state and demonstrates that the -S electronic states are multi-configurational in nature. Then the spectroscopic constants of the bound -S and states are obtained by solving the radial Schrdinger equation. By comparison with experimental results, the spectroscopic constants of ground states are in good agreement with the observed values. The remaining computational results are reported for the first time.
Physical modeling and caculation method of laser pulse superposition in multi-pass amplification process
Authors: Zhang Ying  , Liu Lan-Qin  , Wang Wen-Yi  , Huang Wan-Qing  , Xie Xu-Dong  , Zhu Qi-Hua  ,   Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900, China
Published: December 2020

Physical model and caculation method are established to describe the laser pulse superpositon in multi-pass amplification process. In this model, the inversion pupulation density is consumed by the pulse leading edge and tailing edge simultaneously. It is demonstrated that this model can not solve the problem of laser superposition amplification in the time-delay coordination. The superposition amplification is solved by building a new time-space coorination. Base on the physical model and caculation method, computer simulation is performed and the pulse shape distortion is discussed at different cavity mirror positions in two-pass amplification process.
Analysis of features of the microdisk cavity perpendicular coupler
Authors: Shu Fang-Jie  ,   Department of Physics, Shangqiu Normal University, Shangqiu 476000, China
Published: December 2020

The use of a waveguide perpendicular to boundaries of the microdisk cavity is a newly developed coupling technique. We make a detailed analysis about the adaptation of the cavity size, the adaptation of the wavelength and the expansibility of the ports. The results confirm that the perpendicular coupler is valid in large cavity or multiple bands. It is shown that multiple perpendicular couplers can exchange energy with a microdisk cavity and work as filter, beam splitter, and crossroads of optical path. The usage of perpendicular coupler in integrated optical circuit with microcavity components will make the selection of materials and arrangement of the optical path more flexible.
The beam propagation based on one-dimensional separation modulated photonic lattices
Authors: Qi Xin-Yuan  , Cao Zheng  , Bai Jin-Tao  ,   Department of Physics, The Institute of Photonic and Photonic Technology, Northwest University, Xi’an 710069, China
Published: December 2020

We numerically study the propagations of Gaussian beams in four types of separation modulated photonic lattices. The results shows that the potential wells between double positive hyperbolic secant and rectangular potential barriers and between the potential barriers in the forms of double negative hyperbolic secant and rectangular functions can both support localized linear modes. Moreover, the coupling effects between two linear modes in the potential barriers can be used to realize all-optical switch. Furthermore, the nonlinear localization can also be observed in high power. Our results supply new ideas for all optical switch, light controlling and manipulation in photonic lattices.
A study on the first integrals of harmonic oscillators
Authors: Ding Guang-Tao  ,   College of Physics and Electronic Information, Anhui Normal University, Wuhu 241000, China
Published: December 2020

A concept of fundamental integrals of one-dimensional harmonic oscillator is presented, and other integrals can be constructed by use of fundamental integrals. The above concept and method are extended to multidimensional harmonic oscillators. By directly constructing other integrals from the fundamental integrals, it is proved that there are three independent time-independent integrals for all kinds of two-dimensional harmonic oscillators and there are 2n-1 independent time-independent integrals for n-dimensional harmonic oscillators. The characteristics of the anisotropic two-dimensional harmonic oscillator is discussed when the ratio between two frequencies is rational or irrational number.
Dissipative particle dynamics simulation of multiphase flow through a mesoscopic channel
Authors: Liu Han-Tao  , Liu Mou-Bin  , Chang Jian-Zhong  , Su Tie-Xiong  ,   School of Mechatronice Engineering of North University of China, Taiyuan 030051, China;,   Key Laboratory for Hydrodynamics and Ocean Engineering, of Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China
Published: December 2020

A new conservative interaction potential with short-range repulsion and long-distance attraction is constructed by a quartic equation function. The multiphase flow through a cross-shape mesoscopic channel is simulated by dissipative particle dynamics with this new potential function. The results show that the new method is capable of simulating the flow process and flow pattern.
Inactivation of Hela cancer cells by an atmospheric pressure cold plasma jet
Authors: Huang Jun  , Chen Wei  , Li Hui  , Wang Peng-Ye  , Yang Si-Ze  ,   Key Laboratory of Soft Matter Physics, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Science, Beijing 100190, China;,   Fujian Provincial Key Laboratory for Plasma and Magnetic Resonance, School of Physics and Mechanical and Electrical Engineering, Xiamen University, Xiamen 361005, China
Published: December 2020

An inactivation mechanism study on Hela cancer cells by means of an atmospheric pressure cold plasma jet is presented. Cell morphology is observed under an inverted microscope after plasma treatment. The neutral red uptake assay provides quantitative evaluations of cell viability under different conditions. The effect of the inactivation efficiency of Hela cancer cells in the argon (900 mL/min) with addition of different amount of oxygen (1%, 2%, 4%, 8%) into atmospheric pressure cold plasma jet is discussed under the fixed power 18 W. Results show that 2% O2 addition provides the best inactivation efficiency, and the survival rate can be reduced to 7% after 180 s treatment. When the oxygen addition exceeds 2%, the inactivation efficiency gradually weakens. The effect is not so good as that in pure argon plasma when the oxygen addition arrives at 8%. According to the emission spectrum of the plasmum, it is concluded that the reactive oxygen species in the plasma play a key role in cancer cell inactivation process.
A method to strengthen and toughen Sapphire by codoping of Fe/Ti ions
Authors: Hu Ke-Yan  , Xu Jun  , Tang Hui-Li  , Li Hong-Jun  , Zou Yu-Qi  , Su Liang-Bi  , Chen Wei-Chao  , Yu Hai-Ou  , Yang Qiu-Hong  ,   Department of Electronic Information Materials, Shanghai University, Shanghai 201800, China;,   Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 201800, China
Published: December 2020

Mechanical properties of titanium and iron co-doped Sapphire crystal are first studied at room temperature Large (ø180 × 280 mm3 in dimension 30 kg in weight) titanium and iron codoped sapphire single crystal is grown by the Kyropoulos technique It is shown that the fracture strength and surface hardness and fracture toughness of as-grown crystals are significantly improved and the visible-infrared optical property is not adversely affected by titanium and iron codoping and certain heat treatment. The Fe3+ in the doped Fe2O3 palys a role of substituting Al3+, leading to an in creased internal stress in the crystal. And the Ti4+ in the doped TiO2 crystallizes the second phase needle crystal and brings in a toughening effect through certain heat treatment. As a consequence, the mechanical properties of as-grown sapphire are improved at room temperature. The present work has the realistic significance for developing the sapphires of excellent mechanical properties.
Carrier transport characteristics in CdSe/CdS/Thioglycolic acid ligand quantum dots with a core-shell structure
Authors: Xue Zhen-Jie  , Li Kui-Ying  , Sun Zhen-Ping  ,   State Key Lab of Metastable Materials Technology and Science, Yanshan University, Qinhuangdao 066004, China
Published: December 2020

In the present paper, we synthesize CdSe quantum dots (QDs) that are stabilized by thioglycolic acid according to the water-phase synthesis. The X-ray diffraction and HRTEM results confirm that the samples prepared each possess a sphalerite structure. The EDS and FT-IR spectra of the samples show that a core-shell structure is formed between the CdSe nanoparticles and the ligand. The fine band structures and the characteristics of the surface states in a connection with the structures are identified by the surface photovoltage (SPV) spectrum of the samples. Two SPV response peaks, located at 475 nm (2.61 eV) and 400 nm (3.1 eV), are closely related to the band-band transitions of the core-CdSe and the shell-CdS, respectively; the SPV response at 370 nm (3.35 eV) is correlated with the n → π* transition between the hydroxyl and sulfydryl (or hydroxyl). It is because of an obvious quantum size effect of the samples that both PL line broadens and SPV response intensity increases with the decrease of the grain size of the sample. The change trend of the surface photoacoustic signal intensity is contrary to that of the SPV response intensity of the samples synthesized at varying pH. Moreover, the fine band structures at surfaces and grain boundaries of CdSe QDs prepared are probed by the SPV spectra of the samples at varying pH values. The relationship between the grain size and the photo-generated carrier transport behavior is discussed according to the detected EFISPV results of the QDs.
Thermal transport of graphene nanoribbons embedding linear defects
Authors: Yao Hai-Feng  , Xie Yue-E  , Ouyang Tao  , Chen Yuan-Ping  ,   Institute for Quantum Engineering and Micro-Nano Energy Technology, Faculty of Materials, Optoelectronics and Physics, Xiangtan University, Xiangtan 411105, China
Published: December 2020

Using nonequilibrium Green's function method, the thermal transport properties of zigzag graphene nanoribbons (ZGNR) embedding a finite (semi-infinite or infinite) long linear defect are investigated in this paper. The results show that defect type and defect length have significant influence on the thermal conductance of ZGNR. When the embedded linear defects have the same lengths, thermal conductance of ZGNR embedding t5t7 defect is lower than that of ZGNR embedding Stone-Wales defect. As for the ZGNR embedding finite and the same type defects, their thermal conductance reduce with the increase of the defect length. However, as the linear defect is long enough, the thermal conductance is insensitive to the change of length. By comparing the ZGNRs embedding finite, semi-infinite and infinite long defects, we find that the thermal conductance of ZGNR embedding an infinite long defect is higher than that of ZGNR embedding a semi-infinite defect, while the thermal conductance of the latter is higher than that of ZGNR embedding a finite long defect. This is due to the fact that different structures possess different numbers of scattering interfaces in the phonon transmission direction. The more the scattering interfaces, the lower the thermal conductance is. These thermal transport phenomena are explained by analyzing transmission coefficient and local density of states. These results indicate that linear defects can tune thermal transport property of ZGNR efficiently.
A new ocean surface wind field retrieval method from C-band airborne synthetic aperture radar
Authors: Ai Wei-Hua  , Yan Wei  , Zhao Xian-Bin  , Liu Wen-Jun  , Ma Shuo  ,   College of Meteorology and Oceanography, PLA University of Science and Technology, Nanjing 211101, China;,   Jiangsu Key Laboratory of Meteorological Observation and Information Processing, Nanjing University of Information Science and Technology, Nanjing 210044, China
Published: December 2020

Wind direction retrieval depending on other background sources, e.g., the visible wind-induced streaks, numerical weather prediction model data, scatterometer data and buoy data is the key problem existing in the ocean wind field retrieval using airborne synthetic aperture radar (SAR) data based on geophysical model function which influences the wind speed and direction retrieval accuracies. To solve this problem, a new ocean wind field retrieval method is proposed, with which the wind speed and direction are estimated simultaneously through using the normalized radar cross sections corresponding to different incidence angles and geophysical model function according to the sounding characteristics of airborne SAR. To evaluate the ocean wind field retrieval errors and effects, the simulated data and C band airborne SAR data are used to obtain the wind speed and direction by the proposed method. The verification results show that the wind field retrieval method is suited to retrieve highly accurate wind speed and direction from airborne SAR sounding data without other background sources. The major error can be explained by the insufficient accuracy in calibration of the NRCS for wind speed and wind direction retrieval. The wind speed error increases with the value of speed increasing and at high wind speeds exceeding 18 m/s the error increases distinctly. The value of wind speed has no obvious influence on wind direction retrieval accuracy.
Rapid identification of the consistency of failure mechanism for constant temperature stress accelerated testing
Authors: Guo Chun-Sheng  , Wan Ning  , Ma Wei-Dong  , Zhang Yan-Feng  , Xiong Cong  , Feng Shi-Wei  ,   College of Electronic Information and Control Engineering, Beijing University of Technology, Beijing 100124, China
Published: December 2020

For avoiding the invalid acceleration experiments caused by the changes of the failure mechanism, the relationship of the failure mechanism consistency and the parameters of degradation data distribution in the early stage under different accelerated stress levels has been derived. Conditions for judging the failure mechanism consistency are also given as follows: firstly, the shape parameters of failure distribution has a uniform distribution mi=m, i=1,2,3,···; secondly, the dimension parameter ηi follows the equation ηi=AFi·η. A method to rapidly discriminate the consistency of failure mechanism under different experimental stresses in the early stage was obtained, and the invalid acceleration experiments caused by the changes of the failure mechanism could be avoided. Finally, theoretical degenerate data in the early stage of the accelerated test and the initial degenerate data of the MCM thick-film resistor were used for estimating, Weibull distribution parameter, and the consistency of failure mechanism degradation was also judged.
Study of inhomogeneous tissue equivalent water thickness correction method in proton therapy
Authors: Xie Zhao  , Zou Lian  , Hou Qing  , Zheng Xia  ,   Sichuan Academy of Medical Sciences and Sichuan Provincial People’s Hospital, Joint Laboratory for Medical Physics, Radiation Oncology Center, Chengdu 610072, China;,   Key Laboratory for Radiation Physics and Technology of Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University, Chengdu 610064, China;,   Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Emergency Department, Chengdu 610072, China
Published: December 2020

The inhomogeneous tissue equivalent water thickness correction method is an important part of research in proton radiotherapy. In this paper, we simulate the transport processes of a high-energy proton beam being injected into the water and other materials using Monte-Carlo multi-particle transport code Fluka, and according to the energy deposition distribution we obtain the depth of the Bragg peak when the protons are injected into different materials. Then we fit an analytic formula (R = αE0p) to the relationship between initial proton energy and the depth of the proton Bragg peak in different materials. It is found that for the different energies of proton beam being injected into non-uniform organization, the difference between the Bragg peak depth from fitting and the depth of the proton beam Bragg peaks from Fluka program is less than 1 mm. If we can establish a database about the relationship of Bragg peak ratio between medium and water, with electron density, then the equivalent water thickness correction method will be able to applied to the dose calculation of for homogeneous medium in proton therapy.
"Cumulative Effect" of torrential rain in the middle and lower reaches of the Yangtze River
Authors: Zhang Shi-Xuan  , Feng Guo-Lin  , Zhao Jun-Hu  ,   College of Atmospheric Sciences, Lanzhou University, Lanzhou 730000, China;,   Laboratory for Climate Studies of China Meteorological Administration, National Climate Center, Beijing 100081, China
Published: December 2020

To expand the torrential rain which is a meso-and-micro scale weather process to a meso-and-long scale weather process, in this paper we choose the middle and lower reaches of the Yangtze River (MLRYZ) as a sample region, and propose the conception of "Cumulative Effect" of torrential rain (CETR) by using the daily precipitation observational data from 740 stations in China. On the statistical analysis of observations, we define CETR as the cumulation or superposition of many torrential rain processes, and three indexes, which are continuous time (Ld), control area (Ar) and precipitation contribution rate (Qs), which are used for explaining the conception of CETR. Then taking these three indexes into consideration, we establish the intensity index of CETR (BQDI) and study the relationship between the BQDI and the summer precipitation in MLRYZ. Results show that the interannual and interdecadal variations of BQDI are similar to those of summer precipitation in MLRYZ. The distribution of correlation coefficient between the BQDI and the summer precipitation in Eastern China and the composite analysis of representative years in BQDI show a large positive relation area in MLRYZ (significance test at the 95% level) and two large negative relation areas in North and South China (significance test at the 95% level), which reveals that the variations of BQDI not only correspond to the variations of summer precipitation in MLRYZ but also correlate with the distribution of summer precipitation in Eastern China to some extent. Besides, an empirical orthogonal analysis is performed on the frequency of torrential rain in MLRYZ, we find that the four major spatial modes of torrential rain are also similar to those of summer precipitation in MLRYZ. In conclusion, the precipitation caused by CETR greatly influences even determines the amount and distribution of summer rainfall, which is worth further investigating.
A coordinate compression algorithm based on centroid for wireless sensor networks
Authors: Liu Xiang-Li  , Li Zan  , Hu Yi-Su  ,   State Key Laboratory of Integrated Service Networks, Xidian University, xi’an 710071, China
Published: December 2020

Since communication is often constrainted and the computational resources are limited in wireless sensor networks, it is more important for local sensors to send in compressed data. In this paper, a nonlinear coordinate compression rule is constructed based on arctangent function. Beneficial from the nonlinear feature of arctangent function, near the centroid the compression ratio is low and apart from the centroid the compression ratio becomes higher and higher. The proposed algorithm is more suitable for the signal that has a useful high frequency near centroid. And the proposed algorithm has the following features: the sampling interval is not even; the compression can be done before sampling, which is similar to a compression sensing; it has low computation amount, is simple and easy to implement in a real system.
Explicit and exact traveling wave solutions to the nonlinear LC circuit equation
Authors: Shang Ya-Dong  , Huang Yong  ,   School of Mathematics and Information Science, Guangzhou University, Guangzhou 510006, China;,   Key Laboratory of Mathematics and Interdisciplinary Sciences of Guangdong Higher Education Institutes, Guangzhou University, Guangzhou 510006, China;,   School of Computer Science and Educational Software, Guangzhou University, Guangzhou 510006, China
Published: December 2020

Traveling wave in a nonlinear LC circuit with dissipation have been investigated theoretically. With the aid of the extended hyperbolic function method,developed by the authors in recent works to solve nonlinear partial differential equations exactly, the fourth order nonlinear wave equation with dissipation, which models shock wave propagation in a nonlinear LC circuit, have been analytically studied. Abundant explicit and exact traveling wave solutions to the fourth order nonlinear wave equation with dissipation are obtained. These solutions include exact shock wave solutions, singular traveling wave solutions, and periodic wave solutions in a rational form of trigonometric functions.
The relationship between stochastic resonance and coherence resonance in a bi-stable system
Authors: Dong Xiao-Juan  , Yan Ai-Jun  ,   Department of Mathematics, Xidian University Xi’an 710071, China
Published: December 2020

The phenomenon of stochastic resonance (SR) and coherence resonance (CR) in a bi-stable system driven by additive and multiplicative noises has been investigated. For the case that the system has uncorrelated or correlated additive and multiplicative noises, we introduce an appropriate index that can characterize both SR and CR at the same time. Applying the first-order Euler numerical computation to study the SR and CR, We can show that for small noise density, with the increase of additive noise density, and the appearance of CR, if we add a small periodic force to the bi-stable system, SR will occur almost at the same time. However, with increasing multiplicative noise density, the above conclusion may be satisfied only for correlated additive and multiplicative noises. Moreover, the effects of other parameters on CR and SR can be shown to be the same.
Based on antenna theory to establish the random coupling model of microwave chaotic cavities
Authors: Lu Xi-Cheng  , Wang Jian-Guo  , Liu Yu  , Li Shuang  , Han Feng  ,   Northwest Institute of Nuclear Technology, Xi’an 710024, China;,   School of Electronic and Information Engineering, Xi'an Jiaotong University, Xi'an 710049, China
Published: December 2020

To improve the ability of quickly and effectively resolving the coupling of electrically large complex cavities (microwave chaotic cavities), the statistical properties of the scattering from these cavities have been studied by using a statistical electromagnetics method. Firstly, based on the antenna theory, the input impedance expression of cavities is established by using the expanded electromagnetic eigenmode expression. Secondly, the random coupling model (RCM) is introduced from wave chaos theory and statistical method about microwave chaotic cavities. It is simply to use this method to directly obtain the three-dimensional model. Lastly, the three-dimensional Sinai microwave chaotic cavity is designed, and used to carry out the numerical experiment. Their statistical properties obtained are agreed well with one-another between the numerical result and RCM one. Importantly, the RCM, which is a very good method to be able to quickly predict the sensitivity of coupling about the microwave chaotic cavities, is independent of the details of the cavities.
Studies on soft X-ray shearing interferometry with double-frequency gratings
Authors: Liu Zheng-Kun  , Qiu Ke-Qiang  , Chen Huo-Yao  , Liu Ying  , Xu Xiang-Dong  , Fu Shao-Jun  , Wang Chen  , An Hong-Hai  , Fang Zhi-Heng  ,   National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, China;,   Shanghai Institude of Laser Plasma, Shanghai 201800, China
Published: December 2020

The M-Z interferometer with gratings or multilayer mirrors is widely used in the X-ray laser plasma diagnoses; however, this system is difficult to adjust, and results in the low success rate in experiment. Since wavefront shearing interferometers do not need a separate reference wavefront, they have inherent advantages compared with conventional interferometers. But the absence of shearing element for soft X-ray has restrained the application of the shearing interferometry in soft X-ray measurement. In this paper, a new-structured double-frequency grating was proposed and fabricated that served as the shearing element for soft X-rays, which can promote the application of shearing interferometers in the X-ray laser plasma diagnoses. The diffraction characteristics of the double-frequency grating are analyzed and tested in the synchrotron radiation beams. It is found that the intensity ratio of the two working diffracted beams is over 75%, and the intensity ratio of the rest diffracted beam to the working beam is less than 5%. An X-ray shearing interferometer using a double-frequency grating with 1000 lines/mm and 1002.5 lines/mm gratings was set up, and a clear shear interferogram was obtained. The experimental results demonstrated that the soft X-ray shearing interferometer using double-frequency grating can be applied in the X-ray laser plasma diagnoses.
Electron capture of nuclides 56,57,59,60Co in supernova explosive surrounding
Authors: Liu Jing-Jing  ,   College of Science and Technology, Qiongzhou University, Sanya 572022, China
Published: December 2020

Based on the shell model and random phase approximation theory, and using a shell-model Monte Carlo (SMMC) method, we have investigated the electron capture (EC) for nuclides 56,57,59,60Co, and the rate of change of electron fraction (RCEF) in supernova explosive surroundings. We compared our results, which were obtained by using SMMC method, with those analyzed by using Aufderheide's method. The results show that the EC rates increase greatly, even more than 6 orders of magnitude (e. g. for 57,59,60Co at ρ7=0.43, Ye=0.48). On the other hand, with the increase in temperature and density, the RCEF decreases greatly, even by 5 orders of magnitude (e. g. for 59Co at ρ7=5.86, Ye=0.47). The discussions of error factor show that in a lower density and temperature surrounding, the error is relatively great. But it may be small in the higher density and temperature surroundings.
Temperature diagnostic using photonuclear reactions for hot electrons in laserplasma interactions
Authors: Zhao Jia-Rui  , Yu Quan-Zhi  , Liang Tian-Jiao  , Chen Li-Ming  , Li Yu-Tong  , Guo Cheng-Shan  ,   Department of Physics, Shandong Normal University, Jinan 250014, China;,   Key Laboratory of Optical Physics, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
Published: December 2020

The temperature of hot electrons produced in ultra-short ultra-intense laser-plasma interactions could be measured by photonuclear diagnostic method. In this paper, the process of bremsstrahlung gamma photons generated by hot electrons interacting separately with 63Cu, 107Ag, and 12C, were simulated using the Monte Carlo N-particle transport code (MCNP). According to the different cross-sections, the activities of different samples were calculated. The activity ratios for 11C/62Cu and11C/106Ag were achieved at different electron temperatures. This method can realize the temperature diagnostic of hot electrons in laser-plasma interactions.
The first principle study of electronic and optical properties of defect chalcopyrite XGa2S4 (X=Zn, Cd, Hg)
Authors: Jiao Zhao-Yong  , Guo Yong-Liang  , Niu Yi-Jun  , Zhang Xian-Zhou  ,   College of Physics and Information Engineering, Henan Normal University, Xinxiang 453007, China
Published: December 2020

The electronic and optical properties of the defect chalcopyrite XGa2S4 (X=Zn, Cd, Hg) compounds are studied based on the first-principle calculations. Its structural properties are consistent with the earlier experimental and theoretical results, and its electronic and optical properties are discussed in detail in this paper. The results indicate that the three compounds described hare exhibit an anisotropic behaviour in the intermediate energy range (4 eV10 eV), and an isotropic behaviour in the low(4 eV) or high(10 eV) energy range. The refractive index curves of ZnGa2S4 and HgGa2S4 have an inflection point at the plasma frequency p, and their reflectivity reaches a maximal value at p and then declines sharply. Moreover, the calculated optical properties indicate that these compounds can serve as shielding and detecting devices for ultraviolet radiation.
Stereodynamics study of Li+HF (v = 0–3,j = 0)→LiF+H reaction
Authors: Tan Rui-Shan  , Liu Xin-Guo  , Hu Mei  ,   College of Physics and Electronics, Shandong Normal University, Jinan 250014, China
Published: December 2020

The detailed stereodynamics of the reaction Li+HF(v=0–3) with different collision energy and in different vibration-excited state has been carried out by using the quasi-classical trajectory (QCT) method based on a new potential energy surface constructed by Aguado and Pariagua (Aguado and Paniagua J. Chem. Phys., Vol. 119, No. 19, 2003). The correlated k-j', k-k'-j' angular distributions and the polarization-dependent differential cross sections (PDDCSs) are discussed in detail. The results indicate that the collision energy has more impact on the P(θr) distributions describing the k-j' correlation than the vibration excitation. The distributions of P(φr) describing the k-k'-j' correlation, as well as the polarization-dependent generalized differential cross-sections, are sensitive to the vibration excitation. Meanwhile, the collision energy also has more influence on them.
Combined effect of plasma environment and external magnetic field on hydrogen
Authors: Ding Ding  , Zeng Si-Liang  , Wang Jian-Guo  , Qu Shi-Xian  ,   Institute of theoretical & computational physics, school of physics and information technology, Shannxi Normal University, Xi’an 710062, China;,   Science and Technology Computation Physics Laboratory, Institute of Applied Physics and Computational Mathematics, Beijing 100088, China;,   Data Center for High Energy Density Physics, Institute of Applied Physics and Computational Mathematics, Beijing 100088, China
Published: December 2020

For hydrogen atom imbedded in Debye plasmas with an external magnetic field, the combined effect on bound-bound transitions has been investigated. The electron eigenenergies and wave functions are determined by non-perturbatively solving the Schrdinger equation. Both transition frequencies and oscillator strengths are presented for a wide range of plasma screening parameters and external magnetic field strengths. With increasing the plasma screening, the shielding effects on the Lyman series are shown to be decreased in its intensity and the red-shift of its frequency. After adding an external magnetic field, atomic energy levels undergo even stronger perturbation, and the line shapes become polarized. The non-perturbative effect is significant for the quantum states (n 3). Comparisons made with other theoretical calculations are shown in good agreement. The results reported here may be useful for the interpretation of spectral properties of H-like ions in laboratory and astrophysical Debye plasmas.
Isolated 38 as pulse generation from two-color pulse
Authors: Chen Gao  , Yang Yu-Jun  , Guo Fu-Ming  ,   College of Science, Changchun University of Science and Technology, Changchun 130022, China;,   Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012, China
Published: December 2020

We have investigated theoretically the high-order harmonics and attosecond pulse generation by numerically solving the one-dimensional time-dependent Schrödinger equation from a helium atom in a two-color laser field, which is synthesized by adding a 1330-nm infrared pulse with higher intensity to an 800-nm fundamental pulse with lower intensity. Our results clearly show that if the phase difference between the two pulses is selected suitably, the generation of high-order harmonics spectrum with a broadband supercontinuum characteristic can be achieved, and an isolated 38 as pulse can be realized. By the time-frequency analysis, we find that the isolated attosecond pulse comes from the contribution of the long and short quantum paths, and for these two quantum paths the change of emission time with the harmonics order is rather slow. This is different from the traditional isolated attosecond pulse generation that a single quantum path needs to be picked up to obtain an isolated attosecond pulse.
Irradiation of the water molecule by the femtosecond laser field
Authors: Wang Zhi-Ping  , Wu Ya-Min  , Lu Chao  , Zhang Xiu-Mei  , He Yue-Juan  ,   School of Science, Jiangnan University, Wuxi 214122, China
Published: December 2020

By means of the time-dependent density functional theory (TDDFT) (applied to valence electrons), coupled with non-adiabatically molecular dynamics of ions, the excitation and dynamics of water molecules in a laser field with different polarizations have been explored. It is found that for the same polarization, the water molecule ionization can be enhanced with increasing laser intensity, while the laser intensity keeps constant, the ionization shows a maximum when the polarization is along the molecular symmetry axis, and the ionization is suppressed maximally when the polarization is perpendicular to the symmetry axis of the water molecule. The study of the dipole moment indicates that when the molecule is in the linear response region, there is only the oscillation of Dx for the case of the polarization along the x axis, while there is only the oscillation of Dy for the case of the polarization along the y axis. The bond lengths and the bond angle of H2O molecules are enlarged, while their may ictudes decrease with increasing polarization angle. Furthermore, it is found that in different polarization cases the vibration frequency of OH bonds is almost the same as the laser frequency during the action of the laser field, and it decreases after the laser pulse is switched off; however, the vibration mode of H2O molecule is sensitive to the laser polarization.
Two-dimensional incident left-handed metamaterial composed of double Σ -shaped metal strips
Authors: Tian Zi-Jian  , Chen Wen-Chao  , Fan Jing  ,   School of Mechanical Electronic & Information Engineeriing, China University of Mining and Technology, Beijing 100083, China;,   Department of Electronics and Electrical Engineering, Nanyang Institute of Technology, Nanyang 473004, China
Published: December 2020

A structure of two-dimensional incident left-handed metamaterial composed of double Σ-shaped metal strips is proposed. The structure consists of a dielectric substrate and two anti-symmetrical Σ-shaped metal strips on each side of it, and the structure presents double negative properties (εμ<0), with electromagnetic waves being incident parallel or perpendicular to the substrate. With HFSS software, the two-dimensional incident left-handed properties of the structure are analyzed and verified in X waveband by means of spectrum analysis and effective parameters extracted from S parameters. The two-dimensional incident properties of the structure widen electromagnetic wave angle and are also of reference value for developing multi-dimensional incidence of the metamaterial.
Entanglement and quantum discord in a double J-C model with intensity-dependent coupling
Authors: Hu Yao-Hua  , Tan Yong-Gang  , Liu Qiang  ,   Physics and Electronic Information College, Luoyang Normal University, Luoyang 471022, China
Published: December 2020

Considering a double J-C model with intensity-dependent coupling, we have studied the effects of the intensity-dependent coupling, the mean photon numbers and the atomic motion, on the entanglement and quantum discord between the two two-level atoms when the moving atoms are initially in a maximally entangled state and the fields are in the single-mode thermal fields. The results show that, the entanglement and quantum discord disappear and revive periodically, and can have up to their starting values after revival. A rise in cavity temperature accelerates the death of the entanglement and quantum discord. In addition, the field-mode structural parameter has a strong effect on the entanglement and quantum discord in the system. When the field-mode structural parameter takes a suitable value, the entanglement and quantum discord of the two atoms can be kept from start to finish.
Theoretical analysis and numerical calculation of mode conversion efficiency of fast wave
Authors: Lu Ling  , Zhang Xin-Jun  , Zhao Yan-Ping  , Qin Cheng-Ming  ,   Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, China
Published: December 2020

By considering the effect of high-field-side cutoff, the conventional Budden model has been extended to Triplet model. In this model, the reflection coefficient, transmission coefficient and mode conversion (MC) coefficient of the fast wave for a single evanescence region can be derived through using phase-integral method. Furthermore, numerical calculation of MC coefficient for double-ion species and three-ion species have been done. In the case of double ions, the result is consistent with Kazakov's work. In addition, as an example of three ions plasma, (H, 3He)D plasma in tokamak EAST, simulations of the dependence of the MC efficiency on the magnetic field, microwave frequency and minority concentration for different antenna phasings are carried out. The results show how to choose proper phasing to reach an optimum MC efficiency. This result may provide a reference to improve ICRF heating efficiency.
60Coγ-radiation effects on the ideality factor of AlxGa1?xN p-i-n solar-blind detector with high content of aluminum
Authors: Zhang Xiao-Fu  , Li Yu-Dong  , Guo Qi  , Luo Mu-Chang  , He Cheng-Fa  , Yu Xin  , Shen Zhi-Hui  , Zhang Xing-Yao  , Deng Wei  , Wu Zheng-Xin  ,   Xinjiang technical institute of Physics and Chemistry, University of Chinese Academy of Sciences, Urumqi 830011, China;,   Xinjiang Key Laboratory of Electronic information materials and devices, Urumqi 830011, China;,   Chongqing Optoelectronics Research Institute, Chongqing 400060, China
Published: December 2020

High Al content AlxGa1-xN solar-blind photodetector and Si p-i-n visible light detector were irradiated with 60Co γ-rays up to 0.1, 1, 10 Mrad(Si). With the increase of total radiation dose, the ideality factor of AlxGa1-xN p-i-n diode saw a significant rise and the ideality factor n is grater than 2 with a total dose up to 10 Mrad(Si); the ideality factor of Si p-i-n diode, however, changed only slightly even up to 10 Mrad(Si). The degradation of AlxGa1-xN p-i-n diode might be attributed to the deterioration of Ohmic contacts, however, to some extent, the slight increase of the Si p-i-n diode might be due to the degradation of the insensitive layer.
Microscopic simulation on the dynamic failure of metal Al under triangular wave loading
Authors: Shao Jian-Li  , Wang Pei  , He An-Min  , Qin Cheng-Sen  , Xin Jian-Ting  , Gu Yu-Qiu  ,   Institute of Applied Physics and Computational Mathematics, Beijing 100094, China;,   Laboratory of Computational Physics, Institute of Applied Physics and Computational Mathematics, Beijing 100094, China;,   Research Center of Laser Fusion, CAEP, Mianyang 621900, China
Published: December 2020

Employing an embedded-atom-method potential and molecular dynamics simulations, we have simulated the microscopic process and dynamical properties of the dynamic failure of metal Al specimens under triangular wave loading. The microstructure evolution of the sample is analyzed using the central symmetry parameter, while the difference of morphology between non molten and molten states is also explained. The pressure profiles were calculated based on the virial theorem, and the results show that the tensile strength of the material is decreased considerably in its molten state. Using the simulation results for different impact velocities, we discuss the variation of morphology and density distribution, from which the change of damage depth in the process from non molten to molten states is obtained. Our simulations also suggest that: the tensile strength of material derived from acoustic approximation is distinctively higher than the peak of internal stress from virial theorem for the melted state.
Application of reed-vibration mechanical spectroscopy of liquids for studying dehydration denaturation of protein hydrogel
Authors: Zhou Heng-Wei  , Liu Jun  , Lei Ting  , Huang Yi-Neng  ,   National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing 210093, China;,   Xinjiang Laboratory of Phase Transition and Microstructure in Condensed Matters, College of Physical Science and Technology, Yili Normal University, Yining 835000, China
Published: December 2020

Protein denaturation is not only one of the basic problems in biophysics and biochemistry, but also a practical one in applications. It is undoubtedly useful to explore new methods for detecting protein denaturation because they will surely provide some new information from new angles of view. For the first time, Sofar as we know we apply the reed-vibration mechanical spectroscopy for liquids (RMS-L) to measure the dehydration and denaturation process of egg white, one of typical protein hydrogels, in this work. The results show that there exist at least 4 remarkable processes of mechanical spectra with the reduction of water content. Based on the experiments and the analyses according to the relevant mechanical spectrum theories, the authors inferred that, with the water content reduction egg white may undergo the following 4 states successively: 1) bulk-like water protein hydrogel state; 2) bond water protein hydrogel state; 3) bond water and bonding protein mixed state; 4) bonding protein state. And the spatial configuration change of protein, namely degeneration, happens mainly in the mixed state in which the protein with bond water transforms to binding protein by losing the water. This means that the detection of dehydration and denaturation of egg white by RMS-L is effective, and we think the conclusions would also be reference materials for the deep studies of protein denaturation mechanisms and protein hydrogel states.
The Effect of DC degradation and heat-treatment on defects in ZnO varistor
Authors: Zhao Xue-Tong  , Li Jian-Ying  , Jia Ran  , Li Sheng-Tao  ,   State Key Laboratory of Electrical Insulation and Power Equipment, Xi’an Jiaotong University, Xi’an 710049, China
Published: December 2020

In this research, DC degradation for ZnO varistors at 3.2 kV/cm and 50 mA/cm2 for 115 hours was performed, and its effect on electrical properties and defects of ZnO varistors was investigated. It was found that the breakdown field and nonlinear coefficient drops sharply from 2845 V/cm to 51.6 V/cm and 38.3 to 1.1, respectively, when the DC degradaion time reaches 115 hours. For the degraded sample, the dielectric loss was dominated by the increase of conductivity so that some defect relaxation peaks cannot be observed is the DC degraded ZnO varistors. However, in electrical modulus plot, one relaxation peak can be observed. The conductivity in low frequency range increases greatly and the conductance activation energy drops from 0.84 to 0.083 eV. Additionally, the heat-treatment process of ZnO varistors at 800 ℃ for 24 hours was also performed. It is interesting to note that the electrical properties and the relaxation processes of ZnO varistor is restorable completely again after heat-treatment. The breakdown field and the nonlinear coefficient increase to 3085 V/cm and 50.8, respectively, and the activation energy of conductance increases to 0.88 eV. It is also found that the defect relaxation peak, which is shown in dielectric spectra corresponding to oxygen vacancy defect, is suppressed evidently by heat-retreating. Therefore, it is proposed that oxygen is likely to diffuse into the ZnO grain boundaries at the heat-treatment process, which can play an important role in restorability of the DC degraded ZnO varistor.