bluuebunny/crossref_metadata_2025 huggingface dataset:
Simulation of hot dense plasma’s ionic population: beyond the average atom model
Authors: Wang Min-Sheng  , Liu Ling-Tao  , Han Xiao-Ying  , Li Jia-Ming  ,   (1)清华大学物理系原子分子纳米科学教育部重点实验室，北京  100084; (2)上海交通大学物理系，上海  200030；清华大学物理系原子分子纳米科学教育部重点实验室，北京  100084
Published: December 2020

In theoretical simulations and analysis of diagnostic measurements for hot dense plasmas in the inertial confinement fusion(ICF) researches, it is usually necessary to consider thousands of ionic energy states and transition arrays between these energy states. Average atom(AA) models are generally adopted for practical purposes. In order to calculate ionic populations of hot dense plasmas more accurately, we propose a method beyond the AA model, which can calculate the ionic populations of plasma in local thermal equilibrium with satisfactory accuracy, and may also deal effectively with the ionic populations of plasma in non-local thermal equilibrium.
Numerical simulation of square-lattice photonic crystal fiber with high birefringence and low confinement loss
Authors: Li Shu-Guang  , Xing Guang-Long  , Zhou Gui-Yao  , Hou Lan-Tian  ,   (1)燕山大学理学院红外光纤与传感研究所，秦皇岛  066004; (2)燕山大学理学院红外光纤与传感研究所，秦皇岛  066004;燕山大学亚稳材料制备技术与科学重点实验室，秦皇岛  066004
Published: December 2020

In this paper a square-lattice photonic crystal fiber with gradually increasing air-holes in a silica matrix has been put forward for the first time. The model field, dispersion, birefringence and confinement loss of the fibre fundamental mode are simulated by multipole method. It is found that low confinement loss can be realized under condition of fewer rings of air holes. Simulation shows that birefringence and dispersion of this square-lattice PCF are dominated by inner-ring air holes in the fibre. The simulation results of this paper are highly instructive for the fabrication of birefringent photonic crystal fibers.
A molecular dynamics simulation of thermodynamic properties of undercooled liquid Ni2TiAl alloy
Authors: Yang Hong  , Chen Min  ,   清华大学工程力学系，北京  100084
Published: December 2020

Base on the embedded-atom method，the enthalpy and the density of Ni2TiAl alloy are calculated by using molecular dynamics simulations.The temperature dependence of the specific heat of normal and undercooled liquid Ni2TiAl alloy is obtained.The results indicate that the specific heat and the density increase linearly with the decrease of temperature，and the Neumann-Kopp rule can be applied to estimate the specific heat of undercooled liquid Ni2TiAl alloy. Meanwhile, the size effect in the simulation domain is indicated to be negligible.
Fringe-free spectral phase interferometry for direct electric-field reconstruction
Authors: Lei Liang  , Wen Jin-Hui  , Jiao Zhong-Xing  , Shou Qian  , Wu Yu  , Liu Lu-Ning  , Lai Tian-Shu  , Lin Wei-Zhu  ,   中山大学光电材料与技术国家重点实验室，广州  510275
Published: December 2020

A novel spectral phase interferometry reconstruction for ultrashort optical pulse measurement with high accuracy is presented to overcome the shortcomes of conventional SPIDER. The measured pulse and its two chirped and delayed replicas are mixed synchronously to generate a fringe-free interference pattern. By introducing a suitable small delay into the interference pattern the spectral phase of the measured pulse is retrieved directly and uniquely without using Fourier transformation. This technique is capable of characterizing pulses with long duration or/and complex phase structure.
The effect of quasiperiodicity on lattice distortion and energy gap in spin-Peierls model
Authors: Li Yu-Zhi  , Chen Yu-Guang  , Shi Yun-Long  ,   (1)同济大学波耳固体物理研究所，上海  200092; (2)雁北师范学院固体物理研究所，大同  037009
Published: December 2020

The effect of quasiperiodic interaction on lattice distortion and energy gap in spin-Peierls model is studied by exact diagonalization and self-consistent methods. It is shown that quasiperiodic interaction can result in self-similar characteristics for lattice distortion and energy spectra of spin-Peierls model. Moreover, we find that the average value of lattice distortion will be increased, decreased or increased firstly then decreased as quasiperiodic interaction strength is enhanced. Such kind of behavior strongly depends on the lattice spring constant K. The energy gap also displays similar behavior.
Quasi-vectorial analysis of the optical characteristics of rib waveguides and directional couplers based on InGaAs/InAlAs multiple quantum wells
Authors: Xiao Jin-Biao  , Ma Chang-Feng  , Zhang Ming-De  , Sun Xiao-Han  ,   东南大学电子工程系光子学与光通信研究室，南京  210096
Published: December 2020

A new three-dimensional quasi-vectorial beam propagation method based on the series expansion (SE-QV-BPM) is proposed for simulating the optical rib waveguide and directional coupler based on InGaAs/InAlAs multiple quantum wells. For the same etched-depth, the confinement of TM mode in horizontal direction is shown to be stronger than that of TE mode, and the singular behaviors for TM modes at the corners are clearly observed. For the same gap width, the coupling length of TM mode for directional coupler is larger than that of TE mode. The effective indices and modal profiles of the quasi-vectorial fundamental TE and TM modes for shallow- and deep-etched rib waveguides and directional couplers are obtained. Besides, the evolution of the injected field with propagation distance through the directional coupler is demonstrated. The calculation has good efficiency due to the small size of the resulting matrix, and the rib structures can be conveniently dealt with since the sinusoidal functions are selected as the basis functions. Moreover, the variable transformation is introduced to avoid the boundary truncation.
Magnetic properties of amorphous Fe74Al4Sn2P10C2B4Si4 powder prepared by water atomization and powder core made from it
Authors: Lu Cao-Wei  , Lu Zhi-Chao  , Sun Ke  , Li De-Ren  , Zhou Shao-Xiong  ,   钢铁研究总院安泰科技股份有限公司，北京  100081
Published: December 2020

Fe74Al4Sn2P10C2B4Si4 powder were prepared by water atomization. It has been shown that this alloy has big glass-forming ability (GFA) and high stability against heating. Amorphous alloy powder can be got in size smaller than 400 mesh. Quality factor of the powder core made from this amorphous powder is remarkably higher than that of MPP in high frequency range, which means the core loss of the amorphous powder core is lower than that of MPP. The electrical resistivity of amorphous powder is much higher than that of MPP powder, that is why the amorphous powder core has lower core loss in the high frequency range.
Algebraic representations of polynomial angular momentum algebra and Its realizations
Authors: Wu Chu  ,   清华大学物理系，北京  100084
Published: December 2020

At first the representations of polynomial angular momentum algebra and its unitary ones are obtained appling the way to get the three-parameter Lie algebra representations.Then find the basis which can be acted on by both Lie algebra and the polynomial angular momentum algebra simultaneity,so under such basis the representations of deformed algebras can be shown by introducing the relation of two algebra.At last the deformed algebra's single boson operator realization and one differential realization under finite-dimensional spaces are deduced.
The relation between the entanglement of two atoms and the entanglement of two-mode fields
Authors: Xiong Heng-Na  , Guo Hong  , Jiang Jian  , Chen Jun  , Tang Li-Yan  ,   (1)华中师范大学物理科学与技术学院,武汉  430079; (2)华中师范大学物理科学与技术学院,武汉  430079;中国科学院武汉物理与数学研究所,波谱与原子分子物理国家重点实验室,武汉  430071;中国科学院冷原子物理中心,武汉  430071
Published: December 2020

By means of negativity and concurrence, we investigate the time evolution of the entanglement of the two atoms and the entanglement between the two modes in the system of two atoms interacting with two-mode fields. We find the two entanglements can swap with each other, and they have a very good coincidence relation under certain conditions. In two -qubit system, negativity and concurrence in the same range can keep identical with each other on the standard of the existence of entanglement, but they may not always keep pace with each other for mixed states of the system.
Application of genetic algorithm in optimization of band gap of two-dimensional phononic crystals
Authors: Zhong Hui-Lin  , Wu Fu-Gen  , Yao Li-Ning  ,   (1)广东工业大学实验中心，广州  510090; (2)广州航海高等专科学校，广州  510725
Published: December 2020

A genetic algorithm (GA) with adaptive crossover and mutation probability is developed to design a two-dimensional phononic crystal of a square lattice with maximal absolute band gap. The composites of Pb cylinders in epoxy matrix are studied with GA method connection with plane-wave expansion approach. We find that GA method is effective to find out excellent topology of unit cell with a widest absolute band gap.
Numerical simulation of the Portevin-Le Chatelier effect in annealed aluminum alloys
Authors: Jiang Hui-Feng  , Zhang Qing-Chuan  , Chen Zhong-Jia  , Wu Xiao-Ping  ,   中国科学技术大学，中国科学院材料力学行为和设计重点实验室，合肥  230027
Published: December 2020

By taking into account of the precipitate kinetics and the dynamic strain aging mechanism, a phenomenological model with clear physical origin is established in this paper. Three types of serrated flow in the Portevin-Le Chatelier effect is reproduced by the numerical simulations of the uniaxial tensile tests with different applied strain rates. The computational results are found in good agreement with the experimental curves, which testifies the validity of the present model.
Simulation of the effects of X-ray emission from accretion disks on the interstellar materials
Authors: Wang Wei  , Zhang Jie  , Zhao Gang  ,   (1)中国科学院国家天文台,北京  100012; (2)中国科学院国家天文台,北京  100012;中国科学院物理研究所光物理实验室,北京  100080;首都师范大学物理系，北京  100037; (3)中国科学院物理研究所光物理实验室,北京  100080
Published: December 2020

The thickness of target for X-ray sources with approximate Planck's spectral distribution from laser-produced plasmas is optimized using a one-dimensional radiation hydrodynamics code MULTI. The effect of X-ray radiation field with Planck's distribution on the processes of excitation and ionization in a plasma is stadied using a non-LTE ionized material package NIMP. These results are very important in the future experimental design to study the influence of X-ray emission from accretion disks on interstellar matter.
The percolation simulation of the infection growth models
Authors: Mou Wei-Wei  , Xu Xiao-Liang  ,   中国科学院中国科学技术大学结构分析实验室，合肥  230026;中国科学技术大学物理系，合肥  230026
Published: December 2020

In a regular lattice, the active sites infect their neighboring vacant sites with a certain probability step by step. A grand canonical ensemble was finally formed by all the occupied sites. To represent the system by the partition function of the ensemble, we have substituted the infect probability for the system temperature and divided the energy levels of the sites with different steps. The percolation phase transition of this system at percolation threshold Pc was substantiated by Monte Carlo simulation. Thus a new general method is established, in which the intrinsic behavior of the lattice in the dynamic process of particle growth and other infection growth is used, to estimate the percolation threshold of any lattice. The validity of the model was experimentally verified by studying the growth process of the nanometal films on a dielectric substrate. A proper explanation of the connection between the model and the physical substance was also given.
Ab initio study of the martensitic transformation of NiTi shape memory alloys
Authors: Gong Chang-Wei  , Wang Yi-Nong  , Yang Da-Zhi  ,   大连理工大学材料系，大连  116024
Published: December 2020

In order to systematically understand the mechanism of martensitic transformation of NiTi shape-memory alloy, and to study the effect of temperature and stress on the electronic structure, we have carried out first-principles calculations based on the density-functional theory (DFT). Analysis of density of states shows that martensitic transformation induces the Fermi face to shift and the density of states near the Fermi face to decrease. With the temperature decreasing and deformation increasing,the density of state of B2 phase and the degree of energy band overlaps increase，thus the stability decrease.
Study on the determination of interfacial binding strength of coatings (Ⅰ): theorctical analysis of stress in thin film binding interface
Authors: Zhang Yong-Kang  , Kong De-Jun  , Feng Ai-Xin  , Lu Jin-Zhong  , Zhang Lei-Hong  , Ge Tao  ,   (1)江苏大学机械工程学院，镇江  212013; (2)江苏大学机械工程学院，镇江  212013;华东理工大学机械与动力工程学院，上海  200237
Published: December 2020

The theoretical model of stress in film binding interface is established with the help of laser scratch testing (LST) and the theory of bending stress, the distribution formulae of stress such as shear stress, normal stress and stripping stress are deduced, and the mechanism of stress forming in binding interface is analyzed. It is shown that the normal stress of interface is mainly concentrated on interface center region, it decreases quickly near the interface edge, becomes zero at the interface edge. Shear stress and stripping stress are mainly concentrated in the interface edge, they decrease quickly away from the edge. Normal stress of film is not related with film thickness, matrix thickness and Young's modulus,the shear stress and stripping stress increase with film thickness, and they are determined by thickness of film and matrix and Young's modulus.
Resistivity of Nd1.85Ce0.15CuO4－δ single crystal along c-axis in lower field
Authors: Li Pei-Jun  , Wang Zhi-He  , Bai Zhong  , Nie Yang  , Qiu Li  , Xu Xiao-Nong  ,   南京大学物理系固体微结构国家重点实验室,南京  210093
Published: December 2020

Nd1.85Ce0.15CuO4-δsingle crystals with zero-resistance temperature Tc0≈21K were successfully grown by self-flux slow cooling method. We have measured the resistivity transition curves along the c-axis in different fields parallel or perpendicular to the sample surface, respectively, and at fixed field H=0.5T for various angles. The result shows that the field dependence of differential-resistance peak temperature Tp follows the formula H=H0(1-Tp(h)/Tp(0))2　for H//c-axis and H//ab-plane, respectively. The angular dependence of peak temperature Tp can be scaled by the effective mass model as Tp∝H1/2(cos2θ+sin2θ/γ2)1/4. The anisotropic parameter γ of the crystal is about 45.
Influence of the compacting pressure on the transport properties of CrO2 at low temperatures
Authors: Nie Ying  , Sui Yu  , Song Xiu-Dan  , Wang Xian-Jie  , Cheng Jin-Guang  , Qian Zheng-Nan  , Su Wen-Hui  ,   (1)哈尔滨工业大学物理系凝聚态科学与技术研究中心，哈尔滨  150080; (2)哈尔滨工业大学物理系凝聚态科学与技术研究中心，哈尔滨  150080;辽宁工程技术大学基础科学部，阜新  123000
Published: December 2020

The influence of pressure on the magnetotransport properties of CrO2 samples at low temperatures has been studied in this paper. The X-ray diffraction patterns of the samples show that the relative intensity of (110) peak increases with increasing pressure, which implies that pressure has the orientation effect on the CrO2 needle-shaped nanoparticles. At low temperatures, the resistance and magnetoresistance of CrO2 samples decrease with the increase of pressure. The experimental results suggest that at low temperatures, the conductance of the sample shows the typical characteristic of intergranular tunneling. Δ decreases with increasing pressure and magnetic field; and furthermore, the range of change of Δ with the magnetic field is relatied to the compacting pressure. The higher the compacting pressure, the smaller the variation of Δ with the magnetic field. These changes can be attributed to the adjustment of pressure on the intergranular tunnel barrier.
Study of magnetic properties of Pr2Fe14B/α-Fe nanocomposite magnets
Authors: Pang Li-Jia  , Sun Guang-Fei  , Chen Ju-Fang  , Qiang Wen-Jiang  , Zhang Jin-Biao  , Li Wen-An  ,   (1)北京科技大学材料科学与工程学院，北京  100083; (2)广东省新会市宇宏科技有限责任公司，广东  529100
Published: December 2020

Pr2Fe14B/α-Fe nanocomposite magnets were prepared by the melt-spinning technique. The magnetic properties of the magnets were measured by means of a vibrating sample magnetometer(VSM). Alloy compositions were (PrxFe94.3-xB5.7)0.99Zr1 with x=8.2, 8.6, 9.0, 9.4, 9.8, 10.2, 10.6, 11.0 and 11.4(atomic fraction,%). The effects of the wheel speed and alloy composition on the magnetic properties of melt-spun ribbons were investigated systematically. A decrease of remanence Jr with the increase of atomic fraction of Pr is observed causing an increase in coercivity Hci when changing Pr fraction from 8.2% to 11.4 % which is believed to be the cause of the decrease in maximum energy product (BH)max. Despite the low value of Hci obtained for the 8.2 % Pr alloy, (BH)max is substantially raised by the high Jr which reflects the high volume fraction of α-Fe phase. The Jr, Hci and (BH)max of the best sample quenched at a wheel speed of 25 m/s are 1.37T, 501.19kA/m and 227.93kJ/m3, respectively. The magnetic properties in the direction perpendicular to the ribbon surface are much higher than that in the direction parallel with the ribbon surface.
Self-focusing of ultra-intense short laser pulses in plasmas with various density distributions
Authors: Wang Wei-Min  , Zheng Chun-Yang  ,   (1)北京应用物理与计算数学研究所,北京8009信箱，100088; (2)中国工程物理研究院研究生部,北京2101信箱，100088
Published: December 2020

Effects of plasma density distributions on self-focusing of intense laser pulses propagating in an underdense cold plasma are investigated, where the laser intensity has a Gaussian distribution and the initial plasma density is cylindrical-symmetrically distributed. An evaluation function is derived to judge which type of plasma density distribution is more beneficial for the occurrence of self-focusing. Through analyzing and calculating the evaluation function, it is found that for a given laser field and with fixed initial plasma density along the central axis, which coincides with the axis of the laser beam, increasing plasma density with the distance from the axis favors self-focusing. Furthermore, the greater the density gradient, the more favorable. It is also found that the combined action of both relativistic and ponderomotive effects is of more advantage to self-focusing than that of relativistic effect alone. Numerical simulation confirms that the evaluation function is capable of accurately predicting the favorable role of plasma density distribution in producing laser self-focusing.
Synthesis and characteristics of Bi3.25La0.75Ti3O12 ferroelectric thin films by sol-gel technology
Authors: Wang Hua  , Ren Ming-Fang  ,   桂林电子科技大学信息材料科学与工程系，桂林  541004
Published: December 2020

Bi3.25La0.75Ti3O12 thin films were prepared on p-Si substrates by Sol-Gel technology. The effect of annealing temperature on microstructure, morphology, dielectric and ferroelectric properties of Bi3.25La0.75Ti3O12 films was investigated. Bi3.25La0.75Ti3O12 films annealed at 500℃ were not very uniform, they consisted of small grains and coarse grains with poor dielectric and ferroelectric properties. When the annealing temperature was over 550℃, Bi3.25La0.75Ti3O12 films were uniform and crack free as well as exhibiting no preferred orientation with good dielectric and ferroelectric properties. The leakage current density of Bi3.25La0.75Ti3O12 thin films is 2×10-8A/cm2 at 4V. A noticeable improvement of ferroelectric properties have been obtained when the annealing temperature was increased. Bi3.25La0.75Ti3O12 films annealed at 600℃ showed excellent dielectric and ferroelectric properties with a dielectric constant of 288, a dielectric loss of 1.57%, a remanent polarization of 17.5μC/cm2 and a coercive field of 102kV/cm.
Determination of size distribution of atmospheric aerosol by DOAS
Authors: Si Fu-Qi  , Liu Jian-Guo  , Xie Pin-Hua  , Zhang Yu-Jun  , Dou Ke  , Liu Wen-Qing  ,   中国科学院环境光学与技术重点实验室，中国科学院安徽光学精密机械研究所，合肥  230031
Published: December 2020

With the method of differential optical absorption spectroscopy (DOAS), aerosolalong the light path is monitored and its size distribution is measured with double optical path method. By using double optical path method, the absolute intensity of the source can be determined and the influence of source variation is reduced greatly. Aerosol extinction coefficient from 250nm to 650nm and size distribution from 0.1μm to 1.75μm were obtained. By comparison with optical particle counting, good correlations are found between the DOAS and optical particle counting resulcs.
The research of dynamic structure abrupt change of nonlinear time series
Authors: Gong Zhi-Qiang  , Feng Guo-Lin  , Dong Wen-Jie  , Li Jian-Ping  ,   (1)国家气候中心，中国气象局气候研究开放实验室，北京  100081; (2)扬州大学物理科学与技术学院，扬州  225009；中国科学院大气物理研究所东亚区域气候-环境重点实验室，北京  100029; (3)中国科学院大气物理研究所大气科学和地球流体力学数值模拟国家重点实验室，北京  100029; (4)中国科学院大气物理研究所东亚区域气候-环境重点实验室，北京  100029；国家气候中心，中国气象局气候研究开放实验室，北京  100081
Published: December 2020

For a long time in the past, researches of time series were often based on their external characters and used linear and statistical methods. However, most actual systems are nonlinear, nonstationary and complicated, which increased the diffculties in treating them. The research of abrupt change is one of most important research aspects of nonlinear time series, for which the traditional method based on the external characters of data and using linear process lacks enough physical foundation, and has obvious limitations. How to find out the essence of complicated systems from time series, in other words, to check the abrupt change in dynamical structure of actual data series is a really important problem pending solution. In the present paper, we present a new method——the dynamical correlation exponent segmentation algorithm for checking dynamical abrupt change based on the dynamical lag correlation exponent. The validity of this method is verified by constructing an ideal time series and put it to test. It was found that a few noise spikes have little influence, but continuously distributed white noise has some influence to this new method. Comparison with conventional t-test and Yamamoto method was made to show the relative merits of the methods.
Simulation and design of a W-band gyrotron traveling wave amplifier
Authors: Lai Guo-Jun  , Liu Pu-Kun  ,   (1)中国科学院电子学研究所，北京  100080; (2)中国科学院电子学研究所，北京  100080;中国科学院研究生院，北京  100039
Published: December 2020

Gyrotron traveling wave amplifier is a very important high power millimeter wave source for radar applications. By studying the absolute instability, the gyrotron backward wave oscillation and the interaction between the electron beam and wave, the stability of amplifier and the suppression of spurious oscillations are discussed. The simulation results of W-band TE01 gyrotron traveling wave amplifier are given. The PIC simulation results show that this amplifier can generate 250kW at 94GHz with 28% efficiency and 50dB gain and 5% bandwidth at 100kV,10A electron beam input.
Effects of target configuration on the laser plasma momentum-coupling coefficient
Authors: Zheng Zhi-Yuan  , Zhang Jie  , Hao Zuo-Qiang  , Yuan Xiao-Hui  , Zhang Zhe  , Lu Xin  , Wang Zhao-Hua  , Wei Zhi-Yi  ,   (1)中国科学院物理研究所光物理重点实验室，北京  100080; (2)中国科学院物理研究所光物理重点实验室，北京  100080;中国科学院西安光机所瞬态光学国家重点实验室，西安  710068
Published: December 2020

The plasmas generated in the laser interacting with targets can be used as a new propulsive source. In this paper, the effects of the target configuration on the laser plasma momentum-coupling coefficient are investigated. Results show that, compared with planar targets, the momentum-coupling coefficient is enhanced five times by the cavity target, and over ten times for the confined planar target. It is found that effectively confined plasma expansion is the main reason for the enhancement of the momentum-coupling coefficient.
Square and hexagon pattern formation in dielectric barrier discharge in argon at atmospheric pressure
Authors: Dong Li-Fang  , Li Shu-Feng  , Liu Feng  , Liu Fu-Cheng  , Liu Shu-Hua  , Fan Wei-Li  ,   河北大学物理科学与技术学院，保定  071002
Published: December 2020

Pattern formations in dielectric barrier discharge in argon at atmospheric pressure under different discharge conditions are investigated. Patterns undergo the transition sevies of hexagonal-square-square with glow background-hexagonal with glow background as the applied voltage is increased, and the spatial wavelength and the filament density change also. When the glow background appears under a certain discharge condition, the spatial wavelength and the filaments density remain constant and the number of discharge pulses of each filament in half cycle changes from one to two.
Recovery of statistical property of initial conditions based on time-varying parameter from coupled map lattices
Authors: Liu Ying  , Shen Min-Fen  , Chan Francis H. Y.  ,   (1)汕头大学科学研究院数字图像处理重点实验室,汕头  515063; (2)香港大学工学院,香港
Published: December 2020

To recover the initial conditions of coupled map lattices (CML), which goes athwart the coupled systems, is one of key tasks of signal processing. Based on thecommon symbolic dynamic method, a novel time-varying symbolic dynamic method is proposed. The Logistic map is used to test the properties of the method. Numerical simulation shows that the new scheme can recover the statistical property of the initial conditions from coupled map lattices for both noiseless and noisy signals. The performance of the proposed method is significantly superior to the common method. Moreover, the proposed algorithm has small biases, small mean square errors and a high correlation for the given data. Our new approach is more appropriate to the analysis of practical systems and measurement of coupled systems.
Generalized synchronization of two non-identical systems
Authors: Li Fang  , Hu Ai-Hua  , Xu Zhen-Yuan  ,   (1)江南大学理学院，无锡  214122; (2)江南大学通信与控制工程学院，无锡  214122
Published: December 2020

Generalized synchronization of two non-identical systems is studied based on Temam's inertia manifold theory of infinite dimensional dynamical systems. On the assumption that both systems have absorbing sets and attractors, the generalized synchronization manifold, which has the property of Lipschitz smoothness, invariance and exponential absorption, can be attained by defining a fixed point in a class of functions. Simulation results validate the theory.
Bifurcation control for a non-autonomous system with two time delays
Authors: Qian Chang-Zhao  , Tang Jia-Shi  ,   (1)湖南大学工程力学系，长沙  410082; (2)湖南大学工程力学系，长沙  410082;长沙理工大学桥梁与结构工程学院，长沙  410076
Published: December 2020

A forced system with two time-delays, including van der Pol-Duffing types, is studied. The aim is to study the primary parametrical resonance bifurcation of this system. Perturbation method is used to obtain the bifurcation equation with time-delays. Based on the bifurcation equation, co-dimension one, co-dimension two and Hope bifurcation are discussed, and the effect of time-delays on the steady state response is analyzed by numerical methods. It is indicated that the primary resonance bifurcation can be well controlled by time-delays feedback.
Cubic model of a single-mode laser driven by quadratic pump noise and the steady probability distribution of laser intensity
Authors: Xu De-Sheng  , Cao Li  , Wu Da-Jin  ,   (1)华中科技大学激光技术国家重点实验室，武汉  430074; (2)华中科技大学激光技术国家重点实验室，武汉  430074;中国高等科学技术中心,北京  100080; (3)华中科技大学物理系，武汉  430074;中国高等科学技术中心,北京  100080
Published: December 2020

A single_mode laser cubic model driven with quadratic pump noise is proposed. Closed laser intensity Langevin equation is got. Based on our early work of the Approximation Fokker_Planck equation (AFPE) for the systems driven by nonlinear external noise ［Cao L and Wu D J 1988 Phys. Lett. A 133 476］, the AFPE for laser intensity probability distribution is obtained. Exact analytic expression for the steady normalized intensity probability distribution is calculated. Based on the symmetry of steady normalized intensity probability distribution with respect to λ, the cross_correlation coefficient between the real and imaginary parts of pump noise, several general conclusions on the steady statistical property of laser system are reached.
Method to improve absorption measurement sensitivity of thin films with surface thermal lens technique
Authors: Fan Shu-Hai  , He Hong-Bo  , Shao Jian-Da  , Fan Zheng-Xiu  , Zhao Yuan-An  ,   (1)中国科学院上海光学精密机械研究所，上海  201800; (2)中国科学院上海光学精密机械研究所，上海  201800；中国科学院研究生院，北京  100039
Published: December 2020

In order to improve the sensitivity of surface thermal lens(STL) absorption measurement, numerical simulations are performed based on STL diffraction theory. The optimization method for choosing proper instrument parameters, including the size and position of probe laser waist and the position of detecting fiber, is developed from the simulation. The sensitivity of the instrument reaches 0.1ppm after the optimization.
Calculation of field enhancement factor of the carbon nanotube array
Authors: Wang Miao  , Shang Xue-Fu  , Li Zhen-Hua  , Wang Xin-Qing  , Xu Ya-Bo  ,   (1)浙江大学力学系,杭州  310027; (2)浙江大学物理系，杭州  310027
Published: December 2020

To estimate the apex field enhancement factor associated with an array of carbon nanotubes (CNTs) on a planar cathode surface, the model of floating spheres between parallel anode and cathode plates is proposed. An approximate formula for the enhancement factor is derived, showing that the intertube distance of a CNT array critically affects the field emission. When the intertube distance is less than the height of the tube, the enhancement factor decreases rapidly with decreasing distance, qualitatively in agreement with the numerical simulation. Considering the field emission current density, the field emission can be optimized when the intertube distance is comparable with the tube height, in accordance with the results from experiments. Finally, the influence of the anode-cathode distance on the enhancement factor is also discussed, showing that the anode-cathode distance has little effect on the field emission from CNT array. Thus, we can reduce the threshold voltage to some extent by decreasing the anode-cathode distance.
Influences of W doping at Mn site on magnetic structure of La0.3Ca0.7MnO3 system
Authors: Guo Huan-Yin  , Liu Ning  , Cai Zhi-Rang  , Zhang Yu-Heng  ,   (1)宿州学院材料研究室，宿州  234000; (2)宿州学院材料研究室，宿州  234000；中国科学技术大学结构分析开放实验室，合肥  230026; (3)中国科学技术大学结构分析开放实验室，合肥  230026
Published: December 2020

The influences of W doping at Mn site on the magnetic structure of the charge-ordering system La0.3Ca0.7MnO3 are studied by the measurements of M_T curves,M_H curves and ESR spectra of polycrystalline samples of La0.3Ca0.7Mn1-xWxO3(x=0.00,0.04,0.08,0.12,0.15) are studied. The results show that when the doping amount is 0.00≤x≤0.08, the charge-ordering(CO) phase exists in the system, the AFM/CO states coexist below the transition temperature, and the charge-ordering temperature Tco goes up with the increase of W doping content. For the sample of x=0.04, FM phase and AFM/CO phases coexist at low temperature, and FM is separated from PM both before and after the formation of CO phase; when x≥0.12, CO state melts, and the paramagnetism-ferromagnetism (PM-FM) transition exists at extremely low temperature.
Ferromagnetic resonance in ferromagnetic/antiferromagnetic bilayers under the stress field
Authors: Pan Jing  , Ma Mei  , Zhou Lan  , Hu Jing-Guo  ,   扬州大学物理科学与技术学院，扬州  225002
Published: December 2020

Using a method based on the system energy described by Smith and Beljers, the ferromagnetic resonance in ferromagnetic (FM)/Antiferromagnetic (AFM) bilayers under the stress field is studied. The thin FM film is taken to be a single crystal with cubic and uniaxial magnetocrystalline anisotropies, while the thickness of AFM layer is thin enough for its energy to be neglected. Numerical calculations show that the stress field will affect resonance curve only under weak magnetic field, and the critical field strength which distinguishes the weak from the strong external field depends on the direction of the stress field only.
Effect of introducing Ce3+ on the emission properties of Er3+/Yb3+-doped TeO2-WO3-ZnO glasses
Authors: Li Jia-Cheng  , Xue Tian-Feng  , Fan You-Yu  , Li Shun-Guang  , Hu He-Fang  ,   中国科学院上海光学精密机械研究所，上海  201800
Published: December 2020

Ce3+ ions were introduced into the Er3+/Yb3+-codoped TeO2-WO3-ZnO glasses, and the effect of Ce3+ on the emission properties at 1.5μm band and the upconversion luminescence of Er3+ in the glasses was investigated. With the increasing of Ce3+ concentration, the emission intensity of Er3+ at 1.5μm band increases firstly, and then decreases. The optimal doping concentration of Ce3+ is about 2.07×1020/cm3. As for the Er3+ emission at 1.5-μm band, the fluorescence lifetime decreases a little from 3.4ms to 3.0ms, while the full width at half maximum (FWHM) hardly changes with the increase of Ce3+ concentration. Due to the effective cross relaxation between Ce3+ and Er3+: Er3+(4I11/2)+Ce3+(2F5/2)→Er3+(4I13/2)+Ce3+(2F7/2), the upconversion emission intensity of Er3+ is reduced greatly. But when Ce3+-doping concentration is too high, the other cross relaxation between Ce3+ and Er3+: Er3+(4I13/2)+Ce3+(2F5/2)→Er3+(4I15/2)+Ce3+(2F7/2) happens, which depopulates the 4I13/2 level of Er3+ and results in the decrease of the emission intensity and fluorescence lifetime of Er3+ at 1.5μm band.
On the predictability of the Lorenz system
Authors: He Wen-Ping  , Feng Guo-Lin  , Dong Wen-Jie  , Li Jian-Ping  ,   (1)国家气候中心，中国气象局气候研究开放实验室，北京  100081; (2)国家气候中心，中国气象局气候研究开放实验室，北京  100081;中国科学院大气物理研究所东亚区域气候-环境重点实验室，北京  100029; (3)扬州大学物理科学与技术学院，扬州  225002;中国科学院大气物理研究所东亚区域气候-环境重点实验室，北京  100029; (4)中国科学院大气物理研究所东亚区域气候-环境重点实验室，北京  100029
Published: December 2020

Regarding Lorenz model as the forecast equation，this paper investigates the evolution of the number of particles falling into the predefined dynamic window and the average forecast weight X of the Lorenz system. Then we research preliminarily the predictability of the Lorenz system from another point of views, and the influence of the Gaussian white noises on the Lorenz system. The results show that the evolution of the number reflects the predictability of the Lorenz system to a certain extent. For initial value sets in different areas, there are different predictabilities of the Lorenz system, and we find that there are different influences on the Lorenz system from the Gaussian white noises.
Analysis of the correlation between γ-ray and radio emissions from γ-ray loud Blazar using the discrete correlation function
Authors: Cheng Yong  , Zhang Xiong  , Wu Lin  , Mao Wei-Ming  , You Li-Sha  ,   云南师范大学物理与电子信息学院，昆明  650092
Published: December 2020

In this paper, we collect 119 γ-ray-loud Blazar (97 flat spectrum radio quasars (FSRQs) and 22 BL Lacertae objects (BL Lac)),and investigate respectively the correlation between the γ-ray emission (maximum, minimum, and average data) at 1GeV and the radio emission at 8.4GHz by discrete correlation function (DCF) method. Our main results are as follows: there is good correlation between the γ-ray in high state and average state and radio emissions for the whole 119 Blazar and 97 FSRQs. And there are no correlation between γ-ray emission and radio emission in low state. Our result shows that the γ-rays are associated with the radio emission from the jet, and that the γ-ray emission is likely to have come from the synchrotron self-Compton model (SSC) process in this case.
The hybrid annealed particle filter
Authors: Du Zheng-Cong  , Tang Bin  , Li Ke  ,   (1)电子科技大学电子工程学院，成都  610054; (2)电子科技大学电子工程学院，成都  610054;攀枝学院，攀枝花  617000
Published: December 2020

In this paper, a new particle filter based on sequential importance sampling (SIS) is proposed for the on-line estimation of non-Gaussian nonlinear systems. In this filtering method, state parameters separation and an annealing parameter are used to produce importance function. Since the distribution function makes full use of the prior, likelihood, and statistical characteristics of noise and the newest observation data, it is much closer to posterior distributions. Theoretical analysis and simulation show that the performance of proposed particle filter outperforms the standard particle filter and the extended Kalman filter.
The ribosomal RNA m5C methyltransferase NSUN-1 modulates healthspan and oogenesis in Caenorhabditis elegans
Authors: Heissenberger Clemens , Rollins Jarod A , Krammer Teresa L , Nagelreiter Fabian , Stocker Isabella , Wacheul Ludivine , Shpylovyi Anton , Tav Koray , Snow Santina , Grillari Johannes , Rogers Aric N , Lafontaine Denis L J , Schosserer Markus
Published: December 2020

Our knowledge about the repertoire of ribosomal RNA modifications and the enzymes responsible for installing them is constantly expanding. Previously, we reported that NSUN-5 is responsible for depositing m5C at position C2381 on the 26S rRNA inCaenorhabditis elegans. Here, we show that NSUN-1 is writing the second known 26S rRNA m5C at position C2982. Depletion ofnsun-1ornsun-5improved thermotolerance and slightly increased locomotion at midlife, however, only soma-specific knockdown ofnsun-1extended lifespan. Moreover, soma-specific knockdown ofnsun-1reduced body size and impaired fecundity, suggesting non-cell-autonomous effects. While ribosome biogenesis and global protein synthesis were unaffected bynsun-1depletion, translation of specific mRNAs was remodeled leading to reduced production of collagens, loss of structural integrity of the cuticle, and impaired barrier function. We conclude that loss of a single enzyme required for rRNA methylation has profound and highly specific effects on organismal development and physiology.
Health benefits attributed to 17α-estradiol, a lifespan-extending compound, are mediated through estrogen receptor α
Authors: Mann Shivani N , Hadad Niran , Nelson Holte Molly , Rothman Alicia R , Sathiaseelan Roshini , Ali Mondal Samim , Agbaga Martin-Paul , Unnikrishnan Archana , Subramaniam Malayannan , Hawse John , Huffman Derek M , Freeman Willard M , Stout Michael B
Published: December 2020

Metabolic dysfunction underlies several chronic diseases, many of which are exacerbated by obesity. Dietary interventions can reverse metabolic declines and slow aging, although compliance issues remain paramount. 17α-estradiol treatment improves metabolic parameters and slows aging in male mice. The mechanisms by which 17α-estradiol elicits these benefits remain unresolved. Herein, we show that 17α-estradiol elicits similar genomic binding and transcriptional activation through estrogen receptor α (ERα) to that of 17β-estradiol. In addition, we show that the ablation of ERα completely attenuates the beneficial metabolic effects of 17α-E2 in male mice. Our findings suggest that 17α-E2 may act through the liver and hypothalamus to improve metabolic parameters in male mice. Lastly, we also determined that 17α-E2 improves metabolic parameters in male rats, thereby proving that the beneficial effects of 17α-E2 are not limited to mice. Collectively, these studies suggest ERα may be a drug target for mitigating chronic diseases in male mammals.
Three rules govern thalamocortical connectivity of fast-spike inhibitory interneurons in the visual cortex
Authors: Bereshpolova Yulia , Hei Xiaojuan , Alonso Jose-Manuel , Swadlow Harvey A
Published: December 2020

Some cortical neurons receive highly selective thalamocortical (TC) input, but others do not. Here, we examine connectivity of single thalamic neurons (lateral geniculate nucleus, LGN) onto putative fast-spike inhibitory interneurons in layer 4 of rabbit visual cortex. We show that three ‘rules’ regulate this connectivity. These rules concern: (1) the precision of retinotopic alignment, (2) the amplitude of the postsynaptic local field potential elicited near the interneuron by spikes of the LGN neuron, and (3) the interneuron’s response latency to strong, synchronous LGN input. We found that virtually all first-order fast-spike interneurons receive input from nearly all LGN axons that synapse nearby, regardless of their visual response properties. This was not the case for neighboring regular-spiking neurons. We conclude that profuse and highly promiscuous TC inputs to layer-4 fast-spike inhibitory interneurons generate response properties that are well-suited to mediate a fast, sensitive, and broadly tuned feed-forward inhibition of visual cortical excitatory neurons.
Real-time, low-latency closed-loop feedback using markerless posture tracking
Authors: Kane Gary A , Lopes Gonçalo , Saunders Jonny L , Mathis Alexander , Mathis Mackenzie W
Published: December 2020

The ability to control a behavioral task or stimulate neural activity based on animal behavior in real-time is an important tool for experimental neuroscientists. Ideally, such tools are noninvasive, low-latency, and provide interfaces to trigger external hardware based on posture. Recent advances in pose estimation with deep learning allows researchers to train deep neural networks to accurately quantify a wide variety of animal behaviors. Here, we provide a new DeepLabCut-Live! package that achieves low-latency real-time pose estimation (within 15 ms, >100 FPS), with an additional forward-prediction module that achieves zero-latency feedback, and a dynamic-cropping mode that allows for higher inference speeds. We also provide three options for using this tool with ease: (1) a stand-alone GUI (called DLC-Live! GUI), and integration into (2) Bonsai, and (3) AutoPilot. Lastly, we benchmarked performance on a wide range of systems so that experimentalists can easily decide what hardware is required for their needs.
XLF acts as a flexible connector during non-homologous end joining
Authors: Carney Sean M , Moreno Andrew T , Piatt Sadie C , Cisneros-Aguirre Metztli , Lopezcolorado Felicia Wednesday , Stark Jeremy M , Loparo Joseph J
Published: December 2020

Non-homologous end joining (NHEJ) is the predominant pathway that repairs DNA double-strand breaks in vertebrates. During NHEJ DNA ends are held together by a multi-protein synaptic complex until they are ligated. Here, we use Xenopus laevis egg extract to investigate the role of the intrinsically disordered C-terminal tail of the XRCC4-like factor (XLF), a critical factor in end synapsis. We demonstrate that the XLF tail along with the Ku-binding motif (KBM) at the extreme C-terminus are required for end joining. Although the underlying sequence of the tail can be varied, a minimal tail length is required for NHEJ. Single-molecule FRET experiments that observe end synapsis in real-time show that this defect is due to a failure to closely align DNA ends. Our data supports a model in which a single C-terminal tail tethers XLF to Ku, while allowing XLF to form interactions with XRCC4 that enable synaptic complex formation.
Correlating STED and synchrotron XRF nano-imaging unveils cosegregation of metals and cytoskeleton proteins in dendrites
Authors: Domart Florelle , Cloetens Peter , Roudeau Stéphane , Carmona Asuncion , Verdier Emeline , Choquet Daniel , Ortega Richard
Published: December 2020

Zinc and copper are involved in neuronal differentiation and synaptic plasticity but the molecular mechanisms behind these processes are still elusive due in part to the difficulty of imaging trace metals together with proteins at the synaptic level. We correlate stimulated-emission-depletion microscopy of proteins and synchrotron X-ray fluorescence imaging of trace metals, both performed with 40 nm spatial resolution, on primary rat hippocampal neurons. We reveal the co-localization at the nanoscale of zinc and tubulin in dendrites with a molecular ratio of about one zinc atom per tubulin-αβ dimer. We observe the co-segregation of copper and F-actin within the nano-architecture of dendritic protrusions. In addition, zinc chelation causes a decrease in the expression of cytoskeleton proteins in dendrites and spines. Overall, these results indicate new functions for zinc and copper in the modulation of the cytoskeleton morphology in dendrites, a mechanism associated to neuronal plasticity and memory formation.
Safety Climate in Project-Based Organizations: Multi-Criteria Analysis
Authors: Milijić Nenad , Stojanović Anđelka , Mihajlović Ivan , Jovanović Ivan , Popović Momir
Published: December 2020

Research Question: The aim of this paper is to determine the factors influencing safety climate in different industrial sectors in project-based organizations. Motivation: Systematic research on occupational safety is not so frequent in the Republic of Serbia. The lack of research that deals with safety climate in project-based organizations exploring the attitudes of employees in different industrial sectors is evident. In the research conducted by Milijic et al., (2013) a model for measuring safety climate factors was proposed and the following step is to identify the most important safety climate issues for each industrial sector as a key to fostering better safety performance. Chen et al. (2018a) concluded that engagement at all levels of the company is essential to fostering better safety performances as well as that safety awareness is the most important factor influencing workers' safety efficiency. The authors of the present paper seek those particular factors that adequately describe safety climate in project-based organizations by examining the attitudes of workers in different industrial sectors. Idea: The main idea of this paper is to evaluate and rank safety climate in different industrial sectors and different workplaces considering the following five factors of safety climate: Safety and competence awareness, Occupational safety management commitment, Safety training and tools, Safety practices and procedures and Organizational environment. Data: Safety climate analysis was conducted on a set of data collected as a part of a survey carried out in eleven project-oriented organizations operating in different industrial sectors on the territory of Serbia. Tools: This paper proposes a multi-criteria analysis of the data collected from a national survey using the Entropy-PROMETHEE-GAIA method. Findings: A complete ranking of safety climate in project-oriented organizations based on the opinions of employees in different industrial sectors resulted in Energy as the best-ranked sector. On the other hand, the worst-ranked sector is High-rise construction. The results of the complete ranking of safety climate in project-oriented organizations based on the opinions of employees at different workplaces in different industrial sectors showed that the best-ranked alternatives were manager working places. When it comes to production workers on projects, the most favorable safety climate is in energy workplaces and for non-productive workers, while the most favorable safety climate is on projects in the field of mechanical engineering. Contribution: Adopting the conclusions from the paper can, in practice, improve safety climate along with safety at work in project-based organizations.
O SILENCIAMENTO DAS VOZES SUBALTERNAS NA LITERATURA AFRO-BRASILEIRA: UMA ANALISE DA OBRA “QUARTO DE DESPEJO”, DE CAROLINA MARIA DE JESUS
Authors: Rodrigues Walace , De Morais Patrícia Karla
Published: December 2020

Este artigo busca realizar uma análise a respeito da obra “Quarto de despejo – diário de uma favelada”, de Carolina Maria de Jesus, que nos traz relatos reais sobre a vida em uma favela. Objetiva refletir, através da obra, sobre a temática afro-brasileira, de maneira a compreender sobre o que trata essa literatura afro-brasileira e qual sua relevância em ser inserida nos cânones literários. A metodologia utilizada foi teórica e de cunho bibliográfica. Os resultados mostram a necessidade em conhecer sobre a literatura afro-brasileira, pois entende-se que o uso de suas temáticas na construção de uma sociedade mais consciente e justa faz parte dos processos de desconstrução de estereótipos, de preconceitos e racismo que devem ocorrer em relação aos caminhos que achávamos conhecer sobre a história do negro no país.