bluuebunny/crossref_metadata_2025 huggingface dataset:
A macroscopic model of current-induced magnetization switching based on magnetic dynamic equation
Authors: Ren Min  , Zhang Lei  , Hu Jiu-Ning  , Deng Ning  , Chen Pei-Yi  ,   清华大学微电子学研究所,北京 100084
Published: December 2020

A macroscopic phenomenological model based on the magnetic dynamic equation was proposed to investigate spin-polarized current induced magnetization switching in a nano-scale pseudo-spin-valve structure. The movement and even reversal of the free layer's magnetization resulted from two factors, the net spin flux flowing into the free layer and the spin relaxation within it. The dynamic equation incorporated the spin-dependent scattering at the ferromagnetics/nonmagnetics interfaces, and the relaxation of spin accumulation in the ferromagnetic layer. Conditions of magnetization reversal and the corresponding critical currents were found by solving the dynamic equation analytically. The qualitative and quantitative results agree with most of experiments reported. According to the model, the influencing factors on the critical current were analyzed and the methods to improve device performances were pointed out.
Study of high breakdown-voltage AlGaN/GaN FP-HEMT
Authors: Guo Liang-Liang  , Feng Qian  , Hao Yue  , Yang Yan  ,   西安电子科技大学微电子研究所,宽禁带半导体材料与器件教育部重点实验室,西安 710071
Published: December 2020

Fabrication and the characteristics at room temperature of FP-HEMT are reported, followed by a comparison of the actual characteristics with the conventional HEMT. With the incorporation of field plate, the breakdown voltage was enhanced from 52 to 142V.Comparison between AlGaN/GaN FP-HEMT and the conventional HEMT are also made, using Silvaco, as the simulation tool. The effect of enhancing the breakdown voltage is also investigated.
Control of carrier-envelope phase offset in femtosecond laser with PLL and TV-Rb clock
Authors: Han Hai-Nian  , Zhang Wei  , Tong Juan-Juan  , Wang Yan-Hui  , Wang Peng  , Wei Zhi-Yi  , Li De-Hua  , Shen Nai-Chen  , Nie Yu-Xin  , Dong Tai-Qian  ,   (1)北京大学信息科学技术学院，北京  100871; (2)中国科学院物理研究所计量测试高技术联合实验室，北京  100080
Published: December 2020

With the fast development of the cycle-pulse lasers, the control of the carrier-envelope phase offset (CEO) frequency has been an important research subject in such fields as femtosecond optical frequency metrology, strong field physics and high harmonic generation. In this paper, a different measurement method for CEO is demonstrated and subsequently a better beat frequency signal with the signal-to-noise ratio greater than 40 dB is obtained. Based on this optimized beat frequency signal, the CEO of the Ti:sapphire laser is stabilized to the standard signal of 10 MHz of the microwave reference source TV-Rb clock by using the electronic phase-locked loop techniques and the piezo-transducers which are mounted on the mirror inside the laser cavity to change the frequency and phase. The repetition rate of the Ti:sapphire laser is locked to the same TV-Rb clock simultaneously. The experimental results showed that the stability of the repetition rate reached the same level as the TV-Rb clock and that of the CEO frequency was increased by three orders.
Study of the property of the parameters of bistable stochastic resonance
Authors: Leng Yong-Gang  , Wang Tai-Yong  , Guo Yan  , Wu Zhen-Yong  ,   (1)天津大学管理学院，天津  300027; (2)天津大学机械工程学院，天津  300072
Published: December 2020

Taking a bistable system as a research object, the strategy of choosing parameters for affecting and producing stochastic resonance (SR) is investigated. The system parameters of the bistable system and the frequency parameter of twice sampling are related to each other intrinsically. Their variation can cause changes in the height of the potential barrier, the distance of the potential wells and the transition speed of the particle, causing redistribution of the relative noise energy and leading to different stochastic resonance effects. According to the regularity of the parameter choice for the stochastic resonance, the optimal stochastic resonance can be obtained by choosing these parameters properly, which lays the foundation for further data processing.
On decomposition of typhoon flow field
Authors: Huang Si-Xun  , Cai Qi-Fa  , Xiang Jie  , Zhang Ming  ,   (1)解放军理工大学气象学院，南京 211101; (2)解放军理工大学气象学院，南京 211101；南京大学大气科学系中尺度灾害性天气教育部重点实验室，南京 210093
Published: December 2020

The present paper is concerned with characteristics of flow structures of typhoons, and the double variational method is applied. First, the typhoon flow field is decomposed into two parts: the maximum asymmetric vortex and irrotational environmental flow field. Then the maximum asymmetric vortex is also decomposed into two parts: the maximum symmetric vortex and β-gyres. Finally, typhoon Pearl(2006) is simulated by WRF model(weather research and forcasting model), and flow fields at various times at 500hPa are decomposed using the above method. It turns out that the decomposed flow fields are useful for researches on motion and track prediction of typhoons.
Computer simulation of damage in diamond due to boron-nitrogen co-doping and its annealing
Authors: Li Rong-Bin  , Yu Zhong-Hai  ,   上海电机学院材料成型与控制工程系,上海 200245
Published: December 2020

We report the structural characterization and lattice damage induced by the energetic boron (four atoms in all) and nitrogen atoms (eight atoms in all ) with the energy of 500eV co-doped into diamond film and subsequent annealing by computer simulation based on Tersoff empirical potential. With the increasing number of implanted atoms, the affected volume is enlarged, the radius of the disrupted region reaches to 0.68nm for twelve implanting atoms. As a result of annealing, the atoms of the disrupted core can move for rather long distances up to several lattice sites. The mean bond length after annealing approaches the diamond bond length, as obtained from the pair distribution function. Since it is rich in vacancies on the near surface layer, after annealing the interstitial-vacancy recombination could take place, leading to the redistribution of the stress. Annealing at 800℃ is adequate for the recovery of the implanted diamond lattice.
Physical analysis of the certain results in Z-pinch experiments on the “Qiang Guang-I” generator
Authors: Ning Cheng  , Ding Ning  , Yang Zhen-Hua  ,   北京应用物理与计算数学研究所，北京  100088
Published: December 2020

Starting from the energy necessary for atomic ionization and plasma maintaining, a method is developed to estimate the required energy and implosion velocity for a material to emit a certain shell X-ray radiation in a Z-pinch. The typical load current and voltage in Z-pinch process on “Qiang Guang-I” generator are analyzed to obtain the inductance and the work done by Lorentz force, as well as the effect of load parameters on them. The inductance is not in good agreements with that calculated from the theory based on the shell model of Z-pinch, possibly due to the over simplification of the model and the measurement limitations, such as the measuring points of the current and voltage are always several centimeters away from the load. It is found in the experiments that the inductance increases with the load current until the end of the X-ray radiation pulse, and is saturated at ～100nH. The work done by Lorentz force is maximal when the diameter of tungsten wire array is 8 mm in our experiments. The work done to the load with more wires is greater than that to the load with less wires if the diameters of the wire arrays are the same, say 8 or 10 mm. At the same time, the calculation for optimized masses per unit length of gas-puff and wire array load was carried out for the “Qiang Guang-I” generator on 1.6MA current level. The optimized results show that the tungsten wire array with 8 mm diameter should be the best load for this generator. This is consistent with the experimental result on the “Qiang Guang-I”.
A multifractal approach to palmprint recognition
Authors: Li Tong  , Shang Peng-Jian  ,   北京交通大学理学院，北京 100044
Published: December 2020

The purpose of the present study is to investigate the presence of multifractal behaviors of the palmprint. By studying the probability distribution and the partition function，we show that the palmprints possess multifractal characteristics. The width spread，the maximum of multifractal spectrum，and a parameter which describes the asymmetry of the spectrum are proposed as the distinguishing palmprint features. This may provide some factors of importance for palmprint recognition，and shed some light on the problem of biometric recognition.
Molecular dynamics simulation of the pressure effect on the formation of glassy Cu
Authors: Zhao Jiu-Zhou  , Liu Jun  , Zhao Yi  , Hu Zhuang-Qi  ,   中国科学院金属研究所，沈阳  110016
Published: December 2020

Molecular dynamics simulation has been used to investigate the effect of pressure on the formation of glassy Cu. The results indicate that a higher pressure leads to a strong crystallization tendency during cooling. The glassy Cu formed under high pressures contains more crystal cluster and has a higher degree of order.
Computation of the Ehrlich-Schwoebel barrier to adatom diffusion in heteroepitaxial systems
Authors: Li Jia-Yang  , Li Rong-Wu  , Sun Jun-Dong  , Liu Shao-Jun  ,   北京师范大学物理学系，北京  100875
Published: December 2020

The Ehrlich-Schwoebel (ES) barriers to the diffusion of adatoms (Pd,Ag and Cu) on different bench terraces of fcc Cu are compared by molecular dynamics computation. The computation reveals that: 1) For both heteroepitaxial and homoepitaxial systems, the ES barriers increase similarly with the increase of bench terrace height until a certain height is reached. 2) The ES barrier of adatom Pd is the biggest, the second one is that of adatom Cu, and the smallest one is that of adatom Ag for the hopping diffusion mechanism, while the ES barrier of adatom Ag is the biggest, the second one is that of adatom Cu, and the smallest one is that of adatom Pd for the exchange diffusion mechanism. 3)The ES barrier of exchange is lower than that of hopping mechanism in most cases of bench terraces.
Structures and magnetism of small BnNi(n≤5) clusters
Authors: Lei Xue-Ling  , Wang Qing-Lin  , Yan Yu-Li  , Zhao Wen-Jie  , Yang Zhi  , Luo You-Hua  ,   (1)河南大学物理与电子学院，开封 475004; (2)河南大学物理与电子学院，开封 475004;华东理工大学理学院，上海 200237
Published: December 2020

We report the results of calculations which were performed to investigate the equilibrium structures and electronic and magnetic properties of small BnNi(n≤5) clusters within the framework of density functional theory. We obtained the structures of BnNi(n≤5) clusters at different spin multiplicities and determined the lowest-energy structures of BnNi(n≤5) clusters. The results show that the spin multiplicities of the lowest-energy clusters are 2, 1, 2, 1 and 2, respectively. We also studied the magnetic properties of the lowest-energy clusters systematically and found that both the magnetic moment of Ni atom and the total magnetic moment of clusters oscillate with increasing size.
Simulation and design of a W-band second-harmonic 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 100081;中国人民解放军陆军航空兵学院机载设备系,北京 101123
Published: December 2020

Gyrotron traveling wave amplifier is a very important high power millimeter wave source for radar applications. Second-harmonic operation is of special significance due to its low magnetic field operation. By using an interaction circuit with two-stage distributed-loss, the absolute instability and the gyrotron backward wave oscillation can be suppressed. Nonlinear analysis is used to study the stability and large signal performance of the amplifier. Particle in cell simulation of W-band TE02 gyrotron traveling wave amplifier are also performed. The results show that this amplifier can generate 300 kW at 94 GHz with 15% efficiency and 5% bandwidth in case of a 100 kV, 20 A electron beam input.
Phase space beam matrix method for evaluating geometrical aspect of fractional Fourier transform of light beams
Authors: Chen Bao-Xin  , Li Ming  , Zhang Ai-Ju  ,   (1)浙江科技学院图书馆,杭州 310023; (2)浙江科技学院应用物理系,杭州 310023
Published: December 2020

In this paper, a simple technique to determine the geometrical properties of fractional Fourier transform of paraxial beams based on the phase space beam transformation matrix is presented. Taking the elliptic Gaussian beam as an example, we have compared our analysis technique with that of previous work and found that the present method is more reliable in predicting the geometrical properties of fractional Fourier transform of beams and has the advantage of clear intuitive physical insight into beam propagation and transformation process from a geometrical viewpoint. This technique provides a simple and convenient way to study propagation and transformation properties of light beams in a novel approach.
Interactions in Nb2H and its electronic structure
Authors: Liu Zhi-Ming  , Cui Tian  , Ma Yan-Ming  , Liu Bing-Bing  , Zou Guang-Tian  ,   吉林大学超硬材料国家重点实验室，长春 130012
Published: December 2020

The total energies and electronic structures of differently configured Nb2H are calculated using pseudopotential plane wave method based on density functional theory and generalized gradient approximation. The results show that hydrogen atom favors tetrahedral (T) sites (T-wells) rather than octahedral (O) ones. There exist lower energy paths along adjacent T-T sites and saddle structures at the midpoint of them. When H is at T-site or along the T-T path, its 1s level is less broadened and the 4d, 5s bands of Nb extend downward from the metallic band area, forming an ionic band (sharp peak) separated by a gap of about 1 eV from the metallic valence bands, showing that the hydrogen atom captures one valence electron to form an anion. This low-lying ionic band loses its T-site hybridization features when H moves from T to O site, where the 1s band of H is widely broadened, extending into the metallic valence bands. The band structure changes only slightly when the hydrogen atom moves from one T site to a neighbor one along the lower energy path, keeping the T-configuration features. The calculated phonon spectra of H are dispersive only near special q-points for the system with H at a T site, showing that the hydrogen atom is probably vibraing locally and weakly interacts with other hydrogen atoms. The behavior of H at a trapping site plays an important role in bonding of the surrounding Nb atoms.
Homoclinic chaos in averaged oscillator subjected to combined deterministic and narrow-band random excitations
Authors: Lei You-Ming  , Xu Wei  ,   西北工业大学应用数学系，西安 710072
Published: December 2020

In the present paper, homoclinic chaos in averaged oscillator subjected to combined deterministic and narrow-band random excitations is investigated in detail. The method of multiple-scale is first used to reduce the oscillator subjected to combined deterministic and narrow-band random excitations to an averaged oscillator only under narrow-band random excitation. In order to determine the threshold of random excitation amplitude for the onset of chaos, the stochastic Melnikov technique is then applied to the averaged oscillator with mean-square criterion and it is found that the threshold of random excitation amplitude for the onset of chaos in the oscillator turns from increasing to decreasing as the intensity of the noise increases. On the other hand, another threshold of random excitation amplitude for the onset of chaos is obtained by calculating the largest Lyapunov exponents numerically. The Poincare maps are also used for verifying the conclusion. Qualitatively consistent results are obtained by the analytical and numerical methods.
Phase synchronization of chaotic systems based on nonlinear observers
Authors: Meng Juan  , Wang Xing-Yuan  ,   大连理工大学电子与信息工程学院，大连 116024
Published: December 2020

The phase synchronization problem of autonomous chaotic systems is discussod. Based on the nonlinear state observer algorithm and the pole placement technique, a phase synchronization scheme is designed. The phase synchronization of a new chaotic system is achieved by using this observer controller. Numerical simulations are carried out to verify its effectiveness.
Properties of improved polymer host solid-state dye laser
Authors: Liu Wei  , Fan Rong-Wei  , Li Xiao-Hui  , Chen Hui  , Xia Yuan-Qin  , Chen De-Ying  ,   哈尔滨工业大学光电子技术研究所，哈尔滨 150001
Published: December 2020

The solid-state dye laser exhibits attractive features such as free from pollution, compact in structure and low-cost, the development of tunable solid-state dye lasers is an area of active research. PMMA is a popular host for solid-state dyes. When ethanol was added to PMMA, the host can have some improved properties. In the present paper,research results or the transmission spectra, laser spectra, fluorescence spectra and slope efficiency of the polymer dye lasers are presented. When ethanol concentration is 15%, the polymer has the highest transmission rate in 600—750 nm region. Ethanol has a slight impact on the fluorescence spectra. The bandwidth of laser spectra, of whicl the peak positions shift with the ethanol concentration, is about 7—9 nm FWHM. The relation of output energy versus input energy was also studied, and the experimental results confirmed the theoretical results. The highest slope efficiency attained in the experiment was 49.7% with the ethanol concentration of 15%.
Controlling the photonic bandgap structures via manipulation of refractive index of electromagnetically induced transparency vapor
Authors: Zhuang Fei  , Shen Jian-Qi  , Ye Jun  ,   (1)杭州师范学院理学院凝聚态物理研究所，杭州  310036; (2)浙江大学(紫金港校区)，浙江大学-瑞典皇家工学院光子学联合研究中心(东5教学楼)，杭州  310058
Published: December 2020

A new application of coherent manipulation of EIT (electromagnetically induced transparency) medium is suggested. A two-dimensional photonic cystal with a triangle lattice of elliptic air cylinders, which are filled with the EIT atomic vapor, in the KAs backgroud material is designed. By manipulating the refractive index of the EIT vapor via the external control field, one can obtain the controllable bandgap structure that is sensitive to the variations of external conditions (e.g. the intensity of the control field). It is shown that a large complete bandgap of about 0.0503ωe in the region of high normalized frequency could be achieved by choosing the specific parameters such as the spontaneous decay rate, dephasing rate, Rabi frequency of control light, atomic number density as well as elliptic geometric parameters.
Effect of annealing temperature on luminescence of nanocrystal ZrO2: Eu3+
Authors: Liu Huang-Qing  , Wang Ling-Ling  , Zou Bing-Suo  ,   湖南大学应用物理系，长沙  410082
Published: December 2020

Effect of annealing temperature on luminescence of Eu3+ ions was studied in nanocrystal zirconia prepared by co-precipitation. The results reveal that the crystal phase and shape of the samples the tetragonal crystal phase is stable and the content of O2- ions change with annealing temperature increasing. The emission spectra show strong emission at 595 nm and 604 nm. Under UV (394 nm) irradiation the 604 nm emission intensity change from sample to sample. It is related with the difference in surface defects in the surface of the nanocrystalline samples doped with different Eu3+ ion concentrations. In addition, the annealing temperature affects the charge transfer of the samples. The result reveals the change of CTB is also relative to the surface defects of the samples.
Local boundary integral equation method based on radial basis functions for potential problems
Authors: Dai Bao-Dong  , Cheng Yu-Min  ,   (1)上海大学上海市应用数学和力学研究所，上海  200072; (2)上海大学上海市应用数学和力学研究所，上海  200072；太原科技大学工程力学系，太原  030024
Published: December 2020

Combining the interpolation function, which has the delta function property and is constructed on the basis of radial basis functions and polynomial functions, using the local boundary integral equation method (LBIE), the local boundary integral equation method based on radial basis functions is presented for potential problem in this paper. The corresponding discrete equations are obtained. Comparing with the other meshless boundary integral equation methods, the present method has simpler numerical procedures, lower computation cost and higher accuracy. In addition, the essential boundary conditions can be implemented directly. Some numerical results to show the efficiency of the present method are given.
Dynamic properties and drifting of the solution pattern of cubic nonlinear Schr?dinger equation with varying nonlinear parameters
Authors: Luo Xiang-Yi  , Liu Xue-Shen  , Ding Pei-Zhu  ,   吉林大学原子与分子物理研究所，长春  130012
Published: December 2020

The dynamic properties of one-dimensional cubic nonlinear Schr?dinger equation and drifting of the solution pattern are investigated numerically by using the symplectic method with different nonlinear parameters in the perturbation initial condition. The numerical simulation illustrates that the system shows different dynamic behaviors with varying nonlinear parameters, but the motion in the phase space is regularly recurrent. The results show that the drifting velocity for the small nonlinear parameter is small. With the nonlinear parameter increasing, drifting velocity of the solution pattern becomes faster at the same time of evolution.
Hojman conserved quantities for systems with non-Chetaev nonholonomic constraints in the event space
Authors: Jia Li-Qun  , Zhang Yao-Yu  , Zheng Shi-Wang  ,   (1)江南大学理学院,无锡  214122; (2)平顶山学院电气信息工程学院,平顶山  467002; (3)商丘师范学院物理与信息工程系,商丘  476000
Published: December 2020

Hojman conserved quantities deduced by using the special Lie symmetry, the Noether symmetry and the Mei symmetry for systems with non-Chetaev nonholonomic constraints in the event space are studied. First, the differential equations of motion for the above systems are established. Second, the criterion of the Lie symmetry, the Noether symmetry, the Mei symmetry and the relation between them are obtained. Third, the conservation law obtained by Hojman is generalized and applied to the systems, and Hojman conserved quantities are obtained. An example is given to illustrate the application of the results.
Chaos switch-synchronization for a class of 4-D chaotic systems
Authors: Liu Yang-Zheng  , Jiang Chang-Sheng  , Lin Chang-Sheng  ,   (1)南京工程学院非线性物理研究所,南京  210013; (2)南京航空航天大学自动化学院,南京  210016; (3)南京航空航天大学自动化学院,南京  210016；南京工程学院非线性物理研究所,南京  210013
Published: December 2020

A class of switchable four-dimensional chaotic systems is built by adding an additional state to the three-order Lorenz system or Liu system. Some of its basic dynamical properties are studied briefly, such as the feature of equilibrium, the chaos attractor, Lyapunov exponent and fractal dimension. An electronic circuit is designed to realize the class of switchable four-dimensional chaos systems. A method of chaos switch-synchronization between several chaotic systems based on nonlinear feedback control is proposed. Based on the stability theory, the functions of the nonlinear feedback control for synchronization of these systems are determined and the range of available feedback gain is derived.
Structures and potential energy functions of the ground states of BeH, BeD, BeT molecules
Authors: Xu Mei  , Wang Rong-Kai  , Linghu Rong-Feng  , Yang Xiang-Dong  ,   (1)贵州师范大学理学院，贵阳  550001; (2)四川大学原子与分子物理研究所，成都  610065
Published: December 2020

In this paper，the structures and potential energy functions of the ground states of BeH, BeD, BeT molecules are investigated by quantum mechanical ab initio method in the level of QCISD(T)/aug-cc-pVTZ and CCSD(T)/6-311++G(3df，2pd). The spectroscopic data, ωe，ωeχe，Be，αe and De for the ground states obtained from the calculation are in good agreement with the data from experiment. It indicates that the potential energy functions of BeH, BeD, BeT can be expressed by the corrected Murrell-Sorbie functions.
Differential cryptanalysis of TD-ERCS chaos
Authors: Sheng Li-Yuan  , Wen Jiang  , Cao Li-Ling  , Xiao Yan-Yu  ,   (1)湖南大学数学与计量经济学院,长沙  410082; (2)中南大学物理科学与技术学院,长沙  410083
Published: December 2020

Based on the fundamental principle of differential cryptanalysis and corresponding relation between the iteration of chaotic system and the round of block cipher, two important concepts, namely the iterative differential distribution (IDD) and the differential-invalid exponent (DIE) are proposed, which are used in evaluating chaotic system's power of conteracting the differential cryptanalysis. IDD is defined as the distribution of output differential vs. a given input differential at a varied iterative number, and DIE is defined as the minimal iterative number at which both output differential and input differential are independent of each other. By putting chaotic system into the “naked” state and directly analyzing the IDD, the DIE of chaotic system can be gotten. DIE is a universal, measurable and important characteristic exponent of chaos in studying security of chaos. The tests on both TD-ERCS and Logistic systems indicate that in the parameter region of 90%, DIE of DT-ERCS is equal to 2, which is the minimal DIE in theory.In comparison, DIE of Logistic chaotic system equals 55, hence TD-ERCS is a chaotic system with the power of active immunity to differential cryptanalysis.
Using the MRTD based on Daubechies scaling functions to solve the problem of electromagnetic scattering
Authors: Dai Shao-Yu  , Wu Zhen-Sen  , Xu Yang-Bin  ,   (1)西安电子科技大学理学院，西安  710071; (2)西安建筑科技大学理学院，西安  710055
Published: December 2020

A new method of multiresolution time domain analysis is proposed, which is based on compactly supported Daubechies scaling functions in the electromagnetic scattering of three dimensional objects. The highly linear dispersional properties are investigated. Using the interfaces of MRTD/FDTD technique, the connecting and absorption boundaries are dealt with. Numerical experiments show that, compared with conventional FDTD, this method can reduce cells without sacrificing solution accuracy, and uses less CPU time. Finally, the characteristics of PBG structure are obtained using this scheme.
Structure of image fields in an aplanatic optical system with coherent point source illumination
Authors: Guo Han-Ming  , Chen Jia-Bi  , Zhuang Song-Lin  ,   上海理工大学光学与电子信息工程学院，上海  200093
Published: December 2020

Using the vector Fourier transform and stationary phase method, an integral representation of the structure of image field in an aplanatic system with polarized point source located at arbitrary position on the optical axis is obtained. Effects of wide aperture angle in object space on the structure of image field are examined numerically for the case of linearly polarized illumination. Simulation calculations show that, in a plane perpendicular to the optical axis, if the object space aperture angle is wide, the distribution of magnetic field will not be identical to that of electric field after they are rotated 90° around the optical axis with respect to each other, the contours of distribution of the electric and magnetic energy densities and the Poynting vector are approximately elliptical, and the object space aperture angle is the dominant factor that makes the distribution of Poynting vector lose circular symmetry. At the same time, the major axis of the contour of distribution of the electric energy density is perpendicular to the direction of the electric vector in the object space when using small image aperture angle, and will turn graduately to the same direction as the electric vector in the object space with the increase of image aperture angle. These conclusions are completely different from the predications of the previous theory.
Effect of partial coherence of laser has on the irradiance distribution of coherent combining of fiber laser arrays in far field
Authors: Xiao Rui  , Zhou Pu  , Hou Jing  , Jiang Zong-Fu  , Liu Ming  ,   国防科技大学光电科学与工程学院，长沙  410073
Published: December 2020

When calculating the intensity propagating in the far field in coherent combining of fiber laser arrays, the previous approaches simply assumed that each aperture is a Gaussian amplitude distribution in a general way. The purpose of the present paper is to study the irradiance distribution where master-oscillators are partially coherent light, for example, the Gaussian-Schell model (GSM) beam. Based on the propagation law of partially coherent light, detailed numerical examples are given to illustrate the dependence of irradiance distribution on the coherence parameter of the GSM beam.
Research of magneto-optical rotation of liquid crystal
Authors: Ren Guang-Jun  , Yao Jian-Quan  , Wang Peng  , Zhang Qiang  , Zhang Hui-Yun  , Zhang Yu-Ping  ,   天津大学精密仪器与光电子工程学院激光与光电子研究所,天津  300072；天津大学光电信息科学技术教育部重点实验室,天津  300072
Published: December 2020

The matrix method is employed to analyze the optical activity of liquid crystal, and the matrix presentation of optical rotation is given. The magneto-optical rotation angle of BL-009 nematic liquid crystal is measured using JG-3 type continuous tunable magnetism device and infrared 1350 nm laser. The effect of magnetic field on optical rotation capability of liquid crystal is analyzed in detailed. The threshold of liquid crystal is discussed through experimental testing, and we reached at the conclusion that the rotation direction in liquid crystal is independent of the direction of magnetic field. The obtained result is useful for the design and manufacturing of liquid crystal device.
Properties of p-type GaN etched by inductively coupled plasma and their improvement
Authors: Lü Ling  , Gong Xin  , Hao Yue  ,   西安电子科技大学微电子学院，宽禁带半导体材料与器件教育部重点实验室，西安  710071
Published: December 2020

Our preseut research was focused on the surface properies of the p-type gallium nitride (p-GaN) etched by inductively coupled plasma (ICP). Different methods were used to process the etched surface. The surface condition was investigated by atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). The current voltage measurement was used to show the I-V characteristics of Ni/Au contacts on the sample. The experimental result demonstrated that the NaOH treatment is effective in improving the material surface and the ohmic contact properties.
The study of symmetries and conserved quantities for one-dimensional damped-amplified harmonic oscillators
Authors: Lou Zhi-Mei  ,   绍兴文理学院物理系，绍兴  312000
Published: December 2020

In this paper, a constant of motion of one-dimensional damped-amplified harmonic oscillators is derived from Newton's equations, and the Lagrangian and the Hamiltonian of system are expressed in term of the constant of motion. According to the expression of the Hamiltonian, we make an ansatz for the conserved quantity and then three conserved quantities are obtained by using the definition of Poisson bracket. The Noether symmetry and Lie symmetry of the infinitesimal transformations of the three conserved quantities are studied and the essence of symmetries and conserved quantities are also explained in this paper.
The coulomb potential energy effect on the intensity of the characteristic lines at highly charged ion incendence on Al surface
Authors: Wang Li  , Zhang Xiao-An  , Yang Zhi-Hu  , Chen Xi-Meng  , Zhang Hong-Qiang  , Cui Ying  , Shao Jian-Xiong  , Xu Xu  ,   (1)兰州大学物理系，兰州  730000; (2)中国科学院近代物理研究所，兰州  730000; (3)中国科学院近代物理研究所，兰州  730000；咸阳师范学院物理系，咸阳  712000
Published: December 2020

The Al atomic characteristic spectral lines were induced by the impact of 40Arq+ ions (8≤q≤16; kinetic energy 150keV) on Al surface. The result shows that by Penning impinging and resonant capture, the ion energy is deposited on the Al surface to excite the target atom, which is different from light excitation. Not only are the transitions betweem electronic configurations of the atomic complex excited, but the enhancing tendency of the characteristic spectral line intensity is consistent with the enhancing tendency of the coulomb potential energy of the incident ions with increasing charged states.
A theoretical study on non_first_order effects of BBK model in the (e,2e) process for hydrogen
Authors: Yang Huan  , Gao Kuang  , Wu Xing-Ju  , Zhang Sui-Meng  ,   (1)安徽师范大学物理与电子信息学院，芜湖  241000; (2)安徽师范大学物理与电子信息学院，芜湖  241000;安徽皖西学院数理系原子与分子物理研究所，六安  237012; (3)安徽皖西学院数理系原子与分子物理研究所，六安  237012
Published: December 2020

The triple differential cross sections for electron impact ionization of hydrogen at incident energies of 54.4, 150 and 250eV in the coplanar asymmetric geometry are calculated by use of BBK model and modified BBK model. The present results are compared with the results of first order approximation and experimental measurements. The non-first-order effects of modified BBK model are analysed and discussed. It is found that screening of three bodies in the final state conveys rich information of the non-first-order effects.
Transfer of quantum information via the two-photon process
Authors: Yang Xiong  , Tong Zhao-Yang  , Kuang Le-Man  ,   湖南师范大学物理与信息科学学院，长沙  410081
Published: December 2020

A scheme is presented for transferring quantum information based on interaction between Jaynes-Cummings model with large detuning and two two-level atoms. It can be shown that quantum information can be transferred from one atom to the other atom, or from the cavity mode to the two atoms by manipulating the interactions between cavity field and two atoms, and the information contained in the transferring atom or cavity mode is completely erased.
Influence of dielectric parameters on temporal behavior of dielectric barrier discharge
Authors: Dong Li-Fang  , Wang Hong-Fang  , Liu Wei-Li  , He Ya-Feng  , Liu Fu-Cheng  , Liu Shu-Hua  ,   河北大学物理科学与技术学院，保定  071002
Published: December 2020

The Influences of different temperature and materials of dielectrics on temporal behavior of dielectric barrier discharge in argon at atmospheric pressure are studied by using a device with asymmetric dielectric parameters. It is found that the temporal waveform of discharge current in each half cycle is almost the same at lower applied voltage, whereas the number of discharge current pulses is different in half cycles of different polarity at higher applied voltage. The analysis shows that both temperature and material of dielectrics affect the accumulation of wall charges, resulting in the change of temporal behavior of discharge.
Optoelectronic properties of the red light-emission chelating electrophosphorescent polymers
Authors: Zhen Hong-Yu  , Luo Chan  , Zhu De-Xi  , Ye Hui  , Wang Jun-Pei  ,   (1)华南理工大学高分子光电材料与器件研究所，广州  510640; (2)浙江大学现代光学仪器国家重点实验室，杭州  310024
Published: December 2020

Photo luminesence, electrochemical and electroluminescent properties of the chelating electrophosphorescent polymers with red light-emission were investigated in this paper. The device performances of the polymers were improved by optimizing the structure. Mixing PBD in emission layer was found to decrease the luminous efficiency，but the device performances were enhanced by inserting PVK layer because of the energy transfer from PVK to the chelating polymer. The best performance was achieved in device ITO/PEDOT/PVK/ PFBtpIrm5/Ba/Al with the maximal external quantum efficiency of 4.25 at the CIE coordinates of (0.69，0.29).
Three-photon absorption and dispersion of sub-femtosecond polarization beast in reverse V-type four-level
Authors: Nie Zhi-Qiang  , Li Ling  , Jiang Tong  , Shen Lei-Jian  , Li Pei-Zhe  , Gan Chen-Li  , Song Jian-Ping  , Zhang Yan-Peng  , Lu Ke-Qing  ,   (1)Department of Physics，University of Arkansas，Fayetteville，Arkansas  72701，USA; (2)西安交通大学电子物理与器件教育部重点实验室，西安  710049; (3)西安交通大学电子物理与器件教育部重点实验室，西安  710049;Department of Physics，University of Arkansas，Fayetteville，Arkansas  72701，USA; (4)中国科学院西安光学精密机械研究所瞬态光学技术国家重点实验室，西安  710068
Published: December 2020

We investigate theoretieally the color-locked twin noisy field_correlation effects in fifth_order nonlinear absorption and dispersion of ultrafast polarization beats in the RV type system.We demonstrate a phase_sensitive method for studying the three_photon six_wave mixing due to atomic coherence in this multi_level system.In the limit of the narrowband and tail approximation,the fifth_order nonlinear coefficients are independent of the color_locked noisy lights.In broadband FWM and SWM signals show time asymmetry due to field_correlation,and RDO effect of frequency_time domain.Moreover,the polarization presents RDO oscillation in frequency_domain.The reference signal is a two_photon non_degenerate four_wave mixing signal,which propagates in the direction a little different from the optical path of the SWM signal.This method is used for studying the phase dispersion of the fifth_order dispersion and absorption and for the optical heterodyne detection of the three_photon SWM signal.The fifth_order nonlinear response can be controlled and modified through the color_locked correlation of twin noisy fields.The method of phase sensitive detection can be used to detect the nonlinear absorption and dispersion of the three_photon SWM.
Attenuation characteristics of laser beam in water
Authors: Liu Juan  , Bai Jian-Hui  , Ni Kai  , Jing Hong-Mei  , He Xing-Dao  , Liu Da-He  ,   (1)无损检测技术教育部重点实验室，南昌航空工业学院自动化学院，南昌  330034; (2)无损检测技术教育部重点实验室，南昌航空工业学院自动化学院，南昌  330034;应用光学北京市重点实验室，北京师范大学物理系,北京  100875; (3)应用光学北京市重点实验室，北京师范大学物理系,北京  100875
Published: December 2020

Through different sample lengths the attenuation coefficient of laser beam with different pulse energy was measured experimentally in water. And the effect of stimulated Brillouin scattering on the attenuation characteristics of water was studied. It was found that the attenuation coefficient is dependent on the pulse energy and the line width of the laser, but not a constant, as usually assumed to be. Theoretical analysis is also given.
Robust quantum computation of the quantum kicked Harper model and dissipative decoherence
Authors: Ye Bin  , Xu Wen-Bo  , Gu Bin-Jie  ,   (1)江南大学通信与控制工程学院，无锡  214122; (2)江南大学信息工程学院，无锡  214122
Published: December 2020

The effects of the dissipative decoherence on the quantum computation of the quantum kicked Harper (QKH) model are investigated using the quantum trajectory approach and the quantum Monte Carlo method. The simulation shows that the dynamical localization for the QKH model and the stochastic web in phase space are destroyed by moderate levels of dissipation. Taking the phase damping channel as the noise model, the universal law for fidelity decay and the timescales of reliable computation are analyzed. Compared with the static imperfections, the timescales for reliable computation of the dissipative system drop more quickly with the increase of the number of qubits when the decay rate is under a certain threshold. While above the threshold, the timescales drop more quickly in the presence of static imperfections.
Theoretical study on the dielectronic recombination of highly charged mercury and uranium ions
Authors: Shi Ying-Long  , Dong Chen-Zhong  , Zhang Deng-Hong  , Fu Yan-Biao  ,   (1)西北师范大学物理与电子工程学院，兰州  730070; (2)西北师范大学物理与电子工程学院，兰州  730070；兰州重离子加速器国家实验室原子核理论研究中心，兰州  730000
Published: December 2020

Based on the multiconfiguration Dirac-Fock method, with the recently developed program for the calculation of cross section of dielectronic recombination (DR), the KLL DR process of highly charged mercury and uranium ions from helium-like to boron-like have been systematically studied. For Hg ions, the contributions to the level of doubly excited state from Breit effect and quantum electrodynamic (QED) effect, KLL DR resonant energies, total line width and corresponding DR resonant strength have been calculated and analyzed. A good overall agreement was found between the present calculations and the previous theoretical and experimental result. Based on the calculation of Hg ions, the KLL DR process of highly charged uranium ions was studied theoretically. The comparison of present results with the other theoretical and experimental results has been made.
The role of extracellular matrix phosphorylation on energy dissipation in bone
Authors: Bailey Stacyann , Sroga Grazyna E , Hoac Betty , Katsamenis Orestis L , Wang Zehai , Bouropoulos Nikolaos , McKee Marc D , Sørensen Esben S , Thurner Philipp J , Vashishth Deepak
Published: December 2020

Protein phosphorylation, critical for cellular regulatory mechanisms, is implicated in various diseases. However, it remains unknown whether heterogeneity in phosphorylation of key structural proteins alters tissue integrity and organ function. Here, osteopontin phosphorylation level declined in hypo- and hyper- phosphatemia mouse models exhibiting skeletal deformities. Phosphorylation increased cohesion between osteopontin polymers, and adhesion of osteopontin to hydroxyapatite, enhancing energy dissipation. Fracture toughness, a measure of bone’s mechanical competence, increased with ex-vivo phosphorylation of wildtype mouse bones and declined with ex-vivo dephosphorylation. In osteopontin-deficient mice, global matrix phosphorylation level was not associated with toughness. Our findings suggest that phosphorylated osteopontin promotes fracture toughness in a dose-dependent manner through increased interfacial bond formation. In the absence of osteopontin, phosphorylation increases electrostatic repulsion, and likely protein alignment and interfilament distance leading to decreased fracture resistance. These mechanisms may be of importance in other connective tissues, and the key to unraveling cell–matrix interactions in diseases.
Neutrophil infiltration regulates clock-gene expression to organize daily hepatic metabolism
Authors: Crespo María , Gonzalez-Teran Barbara , Nikolic Ivana , Mora Alfonso , Folgueira Cintia , Rodríguez Elena , Leiva-Vega Luis , Pintor-Chocano Aránzazu , Fernández-Chacón Macarena , Ruiz-Garrido Irene , Cicuéndez Beatriz , Tomás-Loba Antonia , A-Gonzalez Noelia , Caballero-Molano Ainoa , Beiroa Daniel , Hernández-Cosido Lourdes , Torres Jorge L , Kennedy Norman J , Davis Roger J , Benedito Rui , Marcos Miguel , Nogueiras Ruben , Hidalgo Andrés , Matesanz Nuria , Leiva Magdalena , Sabio Guadalupe
Published: December 2020

Liver metabolism follows diurnal fluctuations through the modulation of molecular clock genes. Disruption of this molecular clock can result in metabolic disease but its potential regulation by immune cells remains unexplored. Here, we demonstrated that in steady state, neutrophils infiltrated the mouse liver following a circadian pattern and regulated hepatocyte clock-genes by neutrophil elastase (NE) secretion. NE signals through c-Jun NH2-terminal kinase (JNK) inhibiting fibroblast growth factor 21 (FGF21) and activating Bmal1 expression in the hepatocyte. Interestingly, mice with neutropenia, defective neutrophil infiltration or lacking elastase were protected against steatosis correlating with lower JNK activation, reduced Bmal1 and increased FGF21 expression, together with decreased lipogenesis in the liver. Lastly, using a cohort of human samples we found a direct correlation between JNK activation, NE levels and Bmal1 expression in the liver. This study demonstrates that neutrophils contribute to the maintenance of daily hepatic homeostasis through the regulation of the NE/JNK/Bmal1 axis.
The malaria parasite sheddase SUB2 governs host red blood cell membrane sealing at invasion
Authors: Collins Christine R , Hackett Fiona , Howell Steven A , Snijders Ambrosius P , Russell Matthew RG , Collinson Lucy M , Blackman Michael J
Published: December 2020

Red blood cell (RBC) invasion by malaria merozoites involves formation of a parasitophorous vacuole into which the parasite moves. The vacuole membrane seals and pinches off behind the parasite through an unknown mechanism, enclosing the parasite within the RBC. During invasion, several parasite surface proteins are shed by a membrane-bound protease called SUB2. Here we show that genetic depletion of SUB2 abolishes shedding of a range of parasite proteins, identifying previously unrecognized SUB2 substrates. Interaction of SUB2-null merozoites with RBCs leads to either abortive invasion with rapid RBC lysis, or successful entry but developmental arrest. Selective failure to shed the most abundant SUB2 substrate, MSP1, reduces intracellular replication, whilst conditional ablation of the substrate AMA1 produces host RBC lysis. We conclude that SUB2 activity is critical for host RBC membrane sealing following parasite internalisation and for correct functioning of merozoite surface proteins.
A small number of workers with specific personality traits perform tool use in ants
Authors: Maák István , Roelandt Garyk , d'Ettorre Patrizia
Published: December 2020

Ants use debris as tools to collect and transport liquid food to the nest. Previous studies showed that this behaviour is flexible whereby ants learn to use artificial material that is novel to them and select tools with optimal soaking properties. However, the process of tool use has not been studied at the individual level. We investigated whether workers specialise in tool use and whether there is a link between individual personality traits and tool use in the antAphaenogaster senilis. Only a small number of workers performed tool use and they did it repeatedly, although they also collected solid food. Personality predicted the probability to perform tool use: ants that showed higher exploratory activity and were more attracted to a prey in the personality tests became the new tool users when previous tool users were removed from the group. This suggests that, instead of extreme task specialisation, variation in personality traits within the colony may improve division of labour.
AKAP6 orchestrates the nuclear envelope microtubule-organizing center by linking golgi and nucleus via AKAP9
Authors: Vergarajauregui Silvia , Becker Robert , Steffen Ulrike , Sharkova Maria , Esser Tilman , Petzold Jana , Billing Florian , Kapiloff Michael S , Schett George , Thievessen Ingo , Engel Felix B
Published: December 2020

The switch from centrosomal microtubule-organizing centers (MTOCs) to non-centrosomal MTOCs during differentiation is poorly understood. Here, we identify AKAP6 as key component of the nuclear envelope MTOC. In rat cardiomyocytes, AKAP6 anchors centrosomal proteins to the nuclear envelope through its spectrin repeats, acting as an adaptor between nesprin-1α and Pcnt or AKAP9. In addition, AKAP6 and AKAP9 form a protein platform tethering the Golgi to the nucleus. Both Golgi and nuclear envelope exhibit MTOC activity utilizing either AKAP9, or Pcnt-AKAP9, respectively. AKAP6 is also required for formation and activity of the nuclear envelope MTOC in human osteoclasts. Moreover, ectopic expression of AKAP6 in epithelial cells is sufficient to recruit endogenous centrosomal proteins. Finally, AKAP6 is required for cardiomyocyte hypertrophy and osteoclast bone resorption activity. Collectively, we decipher the MTOC at the nuclear envelope as a bi-layered structure generating two pools of microtubules with AKAP6 as a key organizer.
Translation in amino-acid-poor environments is limited by tRNAGln charging
Authors: Pavlova Natalya N , King Bryan , Josselsohn Rachel H , Violante Sara , Macera Victoria L , Vardhana Santosha A , Cross Justin R , Thompson Craig B
Published: December 2020

An inadequate supply of amino acids leads to accumulation of uncharged tRNAs, which can bind and activate GCN2 kinase to reduce translation. Here, we show that glutamine-specific tRNAs selectively become uncharged when extracellular amino acid availability is compromised. In contrast, all other tRNAs retain charging of their cognate amino acids in a manner that is dependent upon intact lysosomal function. In addition to GCN2 activation and reduced total translation, the reduced charging of tRNAGln in amino-acid-deprived cells also leads to specific depletion of proteins containing polyglutamine tracts including core-binding factor α1, mediator subunit 12, transcriptional coactivator CBP and TATA-box binding protein. Treating amino-acid-deprived cells with exogenous glutamine or glutaminase inhibitors restores tRNAGln charging and the levels of polyglutamine-containing proteins. Together, these results demonstrate that the activation of GCN2 and the translation of polyglutamine-encoding transcripts serve as key sensors of glutamine availability in mammalian cells.