bluuebunny/crossref_metadata_2025 huggingface dataset:
Study on the stability of carbon nanotubes
Authors: Ouyang Yu  , Peng Jing-Cui  , Wang　Hui  , Yi Shuang-Ping  ,   (1)广东工业大学物理与光电工程学院,广州  510009; (2)广东海洋大学理学院，湛江  524088; (3)湖南大学物理与微电子科学学院，长沙  410082
Published: December 2020

When the a graphite crystal is crushed, it is breaks into micro-scale laminar flakes. There are many dangling bonds on the edge of an isolated graphite micro-sheet which elevates its energy and makes it unstable. When a graphite micro-sheet curles into a nano-tube, the number of dangling bonds decrease, and the system energy is reduced accordingly. Meanwhile, the curled sheet obtains deformation energy, which can more than counteract the energy reduction due to the diminished dangling bonds and make the CNT even less favorable energetically than the sheet, and becomes unstable. On the basis of advancing the mechanical model of the formation of CNTs, a thorough theoretical analysis was made, which lead to the conclusion that the CNTs can exist stably at a minimum diameter of approximate 0.32nm.
Molecular noise induced circadian oscillation and coherence resonance in the gene network of biological clock
Authors: Yi Ming  , Jia Ya  , Liu Quan  , Zhan Xuan  ,   华中师范大学物理系和生物物理研究室，武汉  430079
Published: December 2020

The molecular noise in the gene regulation network of biological clock in Drosophila was studied. Especially, we investigated the effect of molecular noise on the circadian rhythmic oscillation when the system is in the steady state region but only slightly away from the oscillating region. We show that (i) Though the prodution and the decay of the protein are stochastic with the stochastic time interval, the obvious circadian oscillation can be induced depending on the system intrinsic regulation mechanism. (ii) The coherence of molecular noise-induced oscillation is optimal under an appropriate molecular noise level, leading to the occurrence of coherence resonance.
UPS study of electronic states of CuPc/Ag(110)
Authors: Dou Wei-Dong  , Song Fei  , Huang Han  , Bao Shi-Ning  , Chen Qiao  ,   (1)圣安德鲁斯大学联合化学学院，英国; (2)浙江大学物理系，杭州  310027; (3)浙江大学物理系，杭州  310027;绍兴文理学院物理与电子信息系，绍兴  312000
Published: December 2020

The electronic structure of copper phthalocyanine (CuPc) adsorbed on Ag (110) surface has been investigated by using the ultra-violet photoemission spectra (UPS). The signals from the 3d band of the substrate Ag atoms faded, while two new peaks grew at 4.45 and 6.36eV below the Fermi level with increasing coverage of CuPc molecules. With further increasing the CuPc coverage, other two peaks can be detected at 1.51 and 9.20 eV below the Fermi level. All four peaks originate from CuPc molecules. With increasing CuPc coverage, the four peaks increase in intensity and shift in binding energy. The results of angular resolved UPS suggest a “flat-lying" mode for CuPc molecules adsorbed on Ag (110) surface. And this has been supported by the theoretical calculation based on the density functional theory (DFT). The theoretical study shows that the CuPc molecule prefers to lie on the hollow position of Ag substrate.
Error analysis of four-intensity algorithm used for the measurement of upper atmosphere
Authors: Ye Jian-Yong  , Zhang Chun-Min  , Zhao Bao-Chang  , Li Ying-Cai  ,   (1)西安交通大学理学院，西安  710049; (2)中国科学院西安光学精密机械研究所，西安  710068
Published: December 2020

With imaging interferometry and Doppler Effect，the information of the upper atmosphere including velocity and temperature can be obtained by measuring four interference intensities of the aurora in the upper atmosphere (80—300km). Theoretical analysis of the measurement error when using four-intensity algorithm in the moving mirror model and divided mirror model is presented respectively. The error of velocity and temperature of the upper atmosphere caused by random phase error is given. By computer simulation，we get the distribution map of velocity error and temperature error in the two models. The result shows that the error of the velocity with the divided mirror model is about half that with the moving mirror model，while the moving mirror model has appreciably higher accuracy for temperature. The research can help us to improve the detection precision of upper atmospheric wind in theory. It has important theoretical significance and practical value both for the research of the detect mode and manufacture of the equipment.
Fabrication of MnSb/Sb functionally graded materials by high gradient magnetic fields
Authors: Gao Ao  , Wang Qiang  , Wang Chun-Jiang  , Liu Tie  , Zhang Chao  , He Ji-Cheng  ,   东北大学材料电磁过程研究教育部重点实验室,沈阳  110004
Published: December 2020

Mn-898wt%Sb alloys were solidified in the absence or presence of high magnetic fields of 88 T with various gradients to investigate the effects of high magnetic fields on the structures of the alloys. It was found that both of the two primary phases, i.e. MnSb and Sb appeared simultaneously in MnSb/Sb eutectic matrix and the MnSb and Sb phase-rich layers were aggregated in different domains under high gradient magnetic field conditions. It was also found that the volume fraction of these two primary phases increased with the increase of the field gradient. This process was attributed to that the alloying element clusters with different susceptibility in molten state were driven along or opposite to the direction of magnetic forces when subjected to high gradient magnetic fields and thus resulted in a layered microstructure with compositional gradient. The results of present study suggest that adjastment of high gradient magnetic field may potentially be used to tailor functionally graded materials.
Analytical potential energy function for the electronic states X2Σ+，A2Π and B2Σ+ of MgH molecule
Authors: Lü Bing  , Zhou Xun  , Linghu Rong-Feng  , Yang Xiang-Dong  , Zhu Zheng-He  ,   (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; (3)四川大学原子与分子物理研究所，成都  610065；贵州师范大学理学院，贵阳  550001
Published: December 2020

The equilibrium geometries of three electronic states X2Σ+，A2Π and B2Σ+ of MgH molecule have been calculated using the SAC-CI and QCISD (T) methods with the basis sets cc-pVQZ，aug-cc-pVTZ，6-311++G and 6-311++G(3df，2pd). Comparing the above mentioned four basis sets，the conclusion is obtained that the basis set 6-311++G (3df，2pd) is the most suitable for the energy calculation of MgH molecule. The whole potential curves for three electronic states are further scanned using QCISD (T)/6-311++G (3df，2pd) method for the ground state and SAC-CI/6-311++G (3df，2pd) method for the excited states. The potential energy functions and relevant spectrum constants ωe，ωexe，Be，αe of these states are obtained by fitting to the Murrell-Sorbie function and the modified Murrell-Sorbie+C6 function，respectively. The results showed that the spectral constants derived from the modified Murrell-Sorbie+C6 function are in very good agreement with the experimental data，and the modified Murrell-Sorbie+C6 function can correctly describe the potential energy function of the ground state and the first degenerate state of MgH molecule.
Electromagnetic scattering by multi-layered spheres in a 2-D Gaussian beam
Authors: Li Hai-Ying  , Wu Zhen-Sen  ,   西安电子科技大学理学院，西安  710071
Published: December 2020

Based on formula of vector wave functions in spherical and cylindrical coordinates and their transformation relations，a new method to solve beam coefficients of a two dimensions (2-D) on-axis Gaussian beam is provided. An analyzical expansion of beam coefficients is obtained. With the help of generalized Lorentz Mie theory，electromagnetic scattering by multi-layered spheres in a 2-D Gaussian beam is deduced. Distribution of scattering intensity changing with scattering angle are simulated. A comparison of scattering intensity with results of incident plane wave is given.
Gray-image information hiding based on kinoform
Authors: Yang Xiao-Ping  , Zhai Hong-Chen  , Wang Ming-Wei  ,   (1)南开大学现代光学研究所，教育部光电信息技术科学重点实验室，天津  300071; (2)南开大学现代光学研究所，教育部光电信息技术科学重点实验室，天津  300071；天津理工大学电子信息与通信工程学院，天津  300191
Published: December 2020

In this paper，a new method of hiding gray-images in a host image by using double-random phase encryption method based on kinoform iterative is presented，through which not only the volume to be hidden can be compressed，but also the optical efficiency in the information extracting can be improved. The decoding process of which will not rely on the original host image，and this method can also be applied to the hiding of binary-images. In the last part of this paper，the efficiency and the robustness of this method is analyzed. Computer simulations are presented to illustrate the effectiveness of this method.
Design and implementation of a PRML detection system for HD-DVD
Authors: Yuan Hai-Bo  , Xu Duan-Yi  , Ma Jian-She  ,   清华大学精密仪器与机械学系，光盘国家工程研究中心，北京  100084
Published: December 2020

A PRML detector suitable for high-density DVD (HD-DVD) system is developed in this paper. After comparing the spectrum characteristics of the linear optical channel model with various PR polynomials (memory length from 4 to 7)，the criteria of determining memory length and coefficients of target PR is given. The simulated SNR-BER curves show that the Viterbi detector's performance is much better when the memory length of PR is seven. The architecture of a Viterbi detector in PRML system is also described. By computer simulation and experiments，it is proved that the performance and speed of the PRML system with memory length seven can completely satisfy the requirements of the HD-DVD system.
Generations of coherent states of single trapped cold ion beyond the Lamb-Dicke limit
Authors: Zhang Miao  , Jia Huan-Yu  ,   西南交通大学现代物理研究所，成都  610031
Published: December 2020

Based on the quantum dynamics of laser-ion interaction beyond the Lamb-Dicke limit，we discuss how to superpose a series of vibrational number states from motional ground state by sequentially applying laser beams. The Q function，Wigner distribution function，and the nonclassical properties such as squeezing effect and anti-bunching effect of the generated superposition states are investigated in detail by numerical method. It is shown that，by controlling the durations of the applied laser pulses，these quantum states could well approach to the well-known coherent states.
Quantum-mechanical calculations of vibrationally resolved cross sections for non-dissociative charge transfer of O3+ with H2
Authors: Wu Yong  , Liu Ling  , Wang Jian-Guo  ,   (1)北京应用物理与计算数学研究所计算物理实验室，北京  100088; (2)北京应用物理与计算数学研究所计算物理实验室，北京  100088；中国科学院近代物理研究所，兰州  730000
Published: December 2020

Charge transfer due to collisions of ground state O3+(2s22p 2P) ions with molecular hydrogen is investigated using the quantum-mechanical molecular-orbital close-coupling (MOCC) method，and electronic and vibrational state-selective cross sections along with the corresponding differential cross sections are calculated for projectile energies of 100，500，1000 and 5000eV/u at the orientation angles of 25°，45° and 89°. The adiabatic potentials and radial coupling matrix elements utilized in the QMOCC calculations were obtained with the spin-coupled valence-bond approach. The infinite order sudden approximation (IOSA) and the vibrational sudden approximation (VSA) are utilized to deal with the rotation of H2 and the coupling between the electron and the vibration of H2. It is found that the distribution of vibrationally resolved cross sections with the vibrational quantum number v′ of H+2(v′) varies with the increment of the projectile energy; and the electronic and vibrational state-selective differential cross sections show similar behaviors: there is a highest platform within a very small scattering angle，beyond which the differential cross sections decrease as the scattering angle increases and lots of oscillating structures appear，where the scattering angle of the first structure decreases as E-1/2p with the increment of the projectile energy Ep; and the structure and amplitude of the differential cross sections are sensitive to the orientation of molecule H2，which provides a possibility to identify the orientations of molecule H2 by the vibrational state-selective differential scattering processes.
Study of three dimensional zonal flows characteristic and novel probe design in HL-2A
Authors: Hong Wen-Yu  , Yan Long-Wen  , Zhao Kai-Jun  , Lan Tao  , Dong Jia-Qi  , Yu Chang-Xuan  , Cheng Jun  , Qian Jun  , Liu A-Di  , Luo Cui-Wen  , Xu Zheng-Yu  , Huang Yuan  , Yang Qing-Wei  ,   (1)核工业西南物理研究院，成都  610041; (2)中国科技大学，合肥  230026
Published: December 2020

Three dimensional(3-D) features of geodesic acoustic mode zonal flows (GAMZF) were first determined with novel three-step zonal flow probes (TSZFP) at the edge of the HL-2A Tokamak plasmas. Three arrays of TSZFP were located 65mm and 800mm apart. The poloidal mode (m～0) and toroidal mode (n～0) of electric potential and field perturbations were simultaneously determined for the first time. Corresponding frequencies were estimated as 7kHz，which are in good agreement with theoretical prediction. The radial scale lengths of ZF were 24—42cm. The formation mechanism of the flows is identified to be nonlinear three wave coupling between high frequency turbulent fluctuations and the flows. The regulating effect of the flows on the ambient turbulent fluctuations was also demonstrated. The Reynolds stress driven by edge fluctuation is one of the main reasons driving the poloidal flow. It is also verified that the radial gradient of Reynolds stress can drive zonal flows.
A left-handed metamaterial composed of structures with both magnetic resonance and electric resonance
Authors: Yang Yi-Ming  , Qu Shao-Bo  , Wang Jia-Fu  , Xu Zhuo  ,   (1)空军工程大学理学院，西安  710051; (2)空军工程大学理学院，西安  710051；西安交通大学电子陶瓷与器件教育部重点实验室，西安  710049; (3)西安交通大学电子陶瓷与器件教育部重点实验室，西安  710049
Published: December 2020

To realise simultaneously negative permittivity and negative permeability in one structure，there must exist both electric resonance and magnetic resonance in the same band for the structure. Based on this principle, we fabricated a structure and investigated its “double-negative” characteristics by means of numerical simulation and experimental test. Compared with other left-handed metamaterials, this structure exhibits simultaneously negative permittivity and negative permeability and its equivalent circuit is much simpler. Moreover, it has much broader left-handed pass-band in which both the permittivity and the permeability are negative. The structures were fabricated by using screen-printing technology, which is much easier and economical.
Q value analysis of a first-order IIR microwave photonic filter based on SOA
Authors: Zhou Li-Na  , Zhang Xin-Liang  , Xu En-Ming  , Huang De-Xiu  ,   (1)华中科技大学武汉光电国家实验室(筹)和光电子科学与工程学院，武汉  430074; (2)华中科技大学武汉光电国家实验室(筹)和光电子科学与工程学院，武汉  430074;中国地质大学物理系，武汉  430074
Published: December 2020

The Q value of a first-order infinite impulse response (IIR) microwave photonic filter based on a semiconductor optical amplifier (SOA) in a loop is investigated theoretically and experimentally. The maximum Q value measured is around 200 by setting a narrow bandwidth optical filter in the active loop and changing the input optical power of the loop and the pump current of the SOA. Analysis shows that increasing the signal to noise ratio and the gain of the signal light through the loop contributes to achieving higher Q value. The influences of the input optical power, the pump current of the SOA and the bandwidth of the optical filter in the loop on the Q value are calculated, based on the amplified spontaneous emission (ASE) noise of the SOA being investigated. Experimental results are in good agreement with the calculated results.
Chaotic digital communication system based on field programmable gate array technology—Design and implementation
Authors: Zhou Wu-Jie  , Yu Si-Min  ,   广东工业大学自动化学院，广州  510006
Published: December 2020

A novel universal approach for design and implementation of chaotic digital communication system based on IEEE-754 standard and field programmable gate array technology (FPGA) is proposed, combing chaos encryption with traditional cipher realization. By using the Euler algorithm and appropriate discrete processing, the continuous chaotic system is converted to a discrete chaotic system. Using FPGA hardware design system, digital chaotic sequence is generated as the key. Scrambling and expansion encryption algorithm is realized and analyzed. Driven and response of secure communication system is designed by constructing a loop including the signal and achieving chaotic synchronization between sender and receiver. Taking grid Chua chaotic system as an example, the secure communication system using FPGA hardware platform is implemented. The technical development process, algorithm flow chart, hardware design and realization result are also given.
Influence of 60Co γ-ray irradiation on AlGaN/GaN high electron mobility transistors
Authors: Gu Wen-Ping  , Zhang Jin-Cheng  , Wang Chong  , Feng Qian  , Ma Xiao-Hua  , 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

AlGaN/GaN high electron mobility transistors (HEMT) unpassivated with different gate lengths are irradiated with 60Co γ-rays to doses up to 1 Mrad(Si). The bigger the doses are and the smaller the gate lengthis, the greater the changes in drain current and transconductanceare. While the gate leakage current is significantly increased after irradiation, the threshold voltage is relatively unaffected. By analysing the series resistance of channel and the threshold voltage, we find that irradiation induced electronegative surface state charges is one of the important reasons of radiation damage.
Distribution of partial electric field and CO molecules adsorbed on the surface of nanostructured nanoellipsoids
Authors: Huang Xiao-Jing  , You Rong-Yi  ,   集美大学理学院物理系，厦门  361021
Published: December 2020

The abnormal infrared effect(AIRE) will happen when CO molecules are adsorbed on the nanostructured transition-metal surface, which can be explained by the partial agglomeration of the adsorbate and the increase of interaction energy due to the effect of external electric field. Based on our previous studies，in this paper, the calculation results are given with respect to the nanoellipsoid growing out from the metal substrate. Based on the surface structure model that the metal nanoellipsoids are arranged symmetrically on a metal substrate in the uniform electric field, the partial electric fields near the nanoellipsoid surfaces are calculated by using the classical electromagnetic theory. On the basis of the calculation results, the CO molecules being modeled as equivalent dipoles, and considering the three kinds of interactions between dipoles and partial electric field, dipole and dipole, as well as dipoles and substrate, we give the spatial configuration of CO molecules adsorbed on the nanoellipsoid surfaces by using Monte-Carlo numerical simulation.
Phenomenon of deep charging in polymer under electron beam irradiation
Authors: Quan Rong-Hui  , Zhang Zhen-Long  , Han Jian-Wei  , Huang Jian-Guo  , Yan Xiao-Juan  ,   (1)中国科学院空间科学与应用研究中心，北京  100190; (2)中国科学院研究生院，北京  100039；中国科学院空间科学与应用研究中心，北京  100190
Published: December 2020

Deep charging and discharging effect is one of the key factors threatening the satellites safety in space environment. We develop a new model and simulate the surface potential evolution, internal charge distribution and electrical field distribution in the polymer charged by electron beam of different intensities. The results are compared with experimental results, which show that the polymer′s surface potential increases with electron beam intensity and its resistance, and the time to reach charging equilibrium is determined mainly by the polymer′s resistance.
Effect of rough interface on the thermoelectric figure of merit of the Bi2Te3/PbTe superlattice
Authors: Mu Wu-Di  , Cheng Hai-Feng  , Chen Zhao-Hui  , Tang Geng-Ping  , Wu Zhi-Qiao  ,   国防科技大学航天与材料工程学院，长沙  410073
Published: December 2020

Electron transport is analysed in Bi2Te3 quantum well of Bi2Te3/PbTe superlattice. The hybrid quantum-classical size effect model, considering the Boltsmann transport equation and classical size effect, is introduced to analyse the effect of rough interface on the electron transport and scattering and the thermoelectric figure of merit of Bi2Te3/PbTe superlattice. The PbTe barrier thickness is kept constant to avoid the influence of the variation in tunnel effect on attenuation of the carrier concentration in Bi2Te3 quantum well of Bi2Te3/PbTe superlattice. The result shows that roughness has strong influence on the thermoelectric figure of merit of Bi2Te3/PbTe superlattice. The Bi2Te3/PbTe thermoelectric figure of merit decreases with the decreasing of the portion (p) of mirror reflection in the hybrid effects. And when p is 0.3, the figure of merit is close to the experiment value.
Effect of annealing pressure on the structure and ferroelectric properties of Bi3.25La0.75Ti3O12 thin films
Authors: Li Jian-Jun  , Yu Jun  , Li Jia  , Yang Wei-Ming  , Wu Yun-Yi  , Wang Yun-Bo  ,   华中科技大学电子科学与技术系，武汉  430074
Published: December 2020

The effect of annealing pressure on the structure and ferroelectric properties was investigated for Bi3.25La0.75Ti3O12(BLT) thin film prepared on Pt/TiO2/SiO2/p-Si(100) substrate by sol-gel method. The amorphous film samples were annealed at 750 ℃ for 30 min under oxygen pressures varying from 10-4 to 3 atm. Then the structure, crystallization degree, and morphology were characterized by X-ray diffraction (XRD), Raman spectroscopy, and field-emission scanning electron microscope (FSEM) to clarify the effect of annealing pressure on the structure of the film. The XRD and Raman spectroscopy results showed a clear decreasing of the crystallization degree of the film annealed under oxygen pressures of 10-4 and 3 atm. FSEM results showed different growth orientations of grains under different oxygen pressures. The structure of the BLT film was revealed to affect their ferroelectric properties. The largest remanent polarization of 17.8 μC/cm2 with the coercive field of 73.6 kV/cm and good fatigue property were obtained for the film annealed under oxygen pressure of 0.1 atm.
Characterization of homoepitaxial and heteroepitaxial diamond films grown by chemical vapor deposition
Authors: Li Rong-Bin  ,   上海电机学院材料成型与控制工程系，上海  200245
Published: December 2020

Sulphur-doped and boron-sulphur co-doped diamond thin films were prepared by using chemical vapour deposition on p-type Si (100) and HTHP-diamond (100) substrates. The structures and properties of CVD diamond films were investigated with atom force microscope (AFM), Raman spectrum, sanning tunneling microscopy (STM) and current imaging tunneling current spectroscopy (CITS). Comparing the structures and properties of the doped diamond films grown on Si and HTHP diamond substrates, we find that the films deposited on Si substrates are composed of spherical grains with size of one hundred nanometer, the doped diamond films on Si substrates consist of large grains with a high fraction of grain boundaries due to the successive secondary nucleation,and the roughness of the films is estimated to be around 18.5nm. The doped diamond films on HTHP diamond substrates are composed of nanometer crystal grains with the sizes of 10—50nm and the film surface is flat with the roughness estimated to be around 1.8nm. Raman and resistivity measurements reveal that the films deposited on HTHP diamond substrates have much higher quality, fewer defects and lower stress, and higher conductivity than the films grown on Si substrates. Current imaging tunnelling current spectroscopy (CITS) images indicate that some grain boundaries and crystalline facets near the grain boundaries are he high electron emission regions. However, the grain boundaries and crystalline facets of the doped diamond films on HTHP diamond substrates have uniform electron emission currents, which indicates that the doped atoms are uniformly distributed in that films. The local I-V characteristics for films deposited on Si or HTHP diamond substrates indicate the n-type conduction.
Effects of secondary neutrons on fast-neutron image quality in thick scintillator
Authors: Zhang Fa-Qiang  , Yang Jian-Lun  , Li Zheng-Hong  , Ye Fan  , Xu Rong-Kun  ,   中国工程物理研究院核物理与化学研究所，绵阳  621900
Published: December 2020

The effects of secondary neutrons on the image quality is simulated using FNRSC (fast neutron radiography simulation code) for a series of scintillator thickness values ranging from 5 mm to 300 mm. The calculated results show that with an incident neutron energy of 14 MeV, the effects of secondary neutrons on the image quality strongly depends on the thickness d of the scintillator for d smaller than 50 mm. When d is higher than 50 mm, this effect is almost saturated. By comparing the image contrast calculated by MCNP (Monte Carlo neutron and photo transport code) with that by FNRSC, we find that the main reasons for the discrepancy is that, the distribution of secondary neutrons strongly depends on that of incident neutrons in the scintillator; contributions of secondany neutrons resulting from energy deposit and fluorescence photons to fast neutron images are different. The results also indicate that a drop occurs in the contrast of neutron images when the elastic scattering cross section between incident neutrons and carbon nucleus is larger.
Computational study of heterogeneous absorption spectra under femtosecond laser pulse
Authors: Wang Lu-Xia  , Fan Fei  ,   北京科技大学应用科学学院物理系，北京  100083
Published: December 2020

Ultrafast heterogeneous electron transfer, including direct transition from the surface attached molecule into the semiconductor band states, is introduced with the focus on a system of perylene on TiO2. The contribution of intramolecule transition and direct electron transition to the absorption spectra are analysed theoretically. By comparing with the intramolecule transition contributions, the ultrafast direct transition contributions to the absorption spectra with different physical parameters are analysed.
The expansion of orthogonal complete set and transformation operator in the teleportation of a three-particle entangled W state
Authors: Shangguan Li-Ying  , Sun Hong-Xiang  , Chen Xiu-Bo  , Wen Qiao-Yan  , Zhu Fu-Chen  ,   (1)北京邮电大学理学院，北京  100876; (2)北京邮电大学网络与交换技术国家重点实验室，北京  100876; (3)北京邮电大学网络与交换技术国家重点实验室，北京  100876；北京邮电大学理学院，北京  100876; (4)现代通信国家重点实验室，成都  610041
Published: December 2020

Firstly，we discuss a scheme for teleportation of a three-particle entangled W state via a two-particle and a three-particle entangled state. Then，in accordance with the principle of superposition and transformation operators，the three-particle entangled W state is expanded by Bell bases and the teleportation can be realized. The relation of transformation operators with unitary operation is discussed. The necessary condition for realizing the teleportation is that the transformation operators have inverse operators.
Synchronization of delayed discrete-time neural networks
Authors: Wu Ran-Chao  ,   安徽大学数学科学学院，合肥  230039
Published: December 2020

Using delayed state-feedback controller and analytic technique, the synchronization control of discrete-time neural network with delay is investigated. Sufficient conditions guaranteeing the synchronized behavior are obtained without assuming the boundedness and differentiability of activation functions. Numerical simulations show the effectiveness of the control scheme.
Bifurcation and attractor of generalized square map with exponential term
Authors: Bao Bo-Cheng  , Kang Zhu-Sheng  , Xu Jian-Ping  , Hu Wen  ,   (1)电子科技大学电子工程学院，成都  610054; (2)南京理工大学电子工程系，南京  210094; (3)南京理工大学电子工程系，南京  210094；江苏技术师范学院电气信息工程学院，常州  213001; (4)西南交通大学电气工程学院，成都  610031
Published: December 2020

By extending the square map，a one-dimensional generalized square map with exponential term is constructed，and its corresponding two-dimensional map is obtained via one-order coupled item in this paper. By using the one-parameter bifurcation diagram，two-parameter dynamics behavior distribution diagram，iterative mapping curve and attractor phase graphics，these generalized square maps are analyzed and simulated. The research results indicate that one-dimensional generalized square map distributes in the unit region and has the nonlinear dynamical phenomenon similar to single-peak square map，and two-dimensional generalized square map has the phenomenon of Hopf bifurcation and locked-frequency shown with complex，flexible and strange-shaped limit cycles and chaotic attractors.
The dynamics of Rydberg atom in an electric field near the saddle point
Authors: Gao Song  , Xu Xue-You  , Zhou Hui  , Zhang Yan-Hui  , Lin Sheng-Lu  ,   山东师范大学物理与电子科学学院，济南  250014
Published: December 2020

The system composed of Rydberg Li atom in an electric field is chaotic because of the core scattering. The period orbits and the closed orbits both exist near the saddle point. The dynamics of this system is studied with the closed-orbit-theory and Poincaré SOS method. The relations of the two methods are discussed for the first time and new information is obtained which can't be retrieved from the recurrence spectra.
The equation of state of the isospin asymmetrical nuclear matter
Authors: Liu Jian-Ye  , Guo Wen-Jun  , Zuo Wei  , Li Xi-Guo  ,   (1)上海理工大学，上海  200093; (2)天水师范学院数理信息学院，天水  741000；中国科学院近代物理研究所，兰州  730000；中国科学院兰州重离子加速器国家实验室原子核理论中心，兰州  730000; (3)中国科学院近代物理研究所，兰州  730000；中国科学院兰州重离子加速器国家实验室原子核理论中心，兰州  730000
Published: December 2020

In order to determine the equation of state in the sospin asymmetrical nuclear matter，we have been engaged in find an experimental observable which sensitively shows the information of the nucleon-nucleon cross section and the symmetry potential in the intermediate energy heavy ion collision by using the isospin dependent quantum molecular dynamics in recent years. As a result, we have found several sensitive probes for extracting the information of the in-medium nucleon-nucleon cross section and the symmetry potential in the equation of state of the isospin asymmetrical nuclear matter. The mechanism of the above probes are investigated in detail. A brief summary and comments on the above results and the prospect of finding more probes in the future are presented.
A method to determine the orientations of adsorbed molecules by near edge structures and selection rules
Authors: Zhang Wei-Hua  , 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)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；上海交通大学物理系，上海市激光制造与材料改性重点实验室，上海  200030
Published: December 2020

Since non-diffuse molecular orbitals （NMOs） are insensitive to environment，when molecules are adsorbed and not broken，the near edge structures involving NMOs will still resemble structures of corresponding free molecules. If we probe adsorbed molecules with polarized X-ray photons，relative intensities of photoabsorption spectra near molecular edges will be different for various geometric arrangement of X-ray polarization. Such features can be used to determine orientations of adsorbed molecules.
Laser cooling of rubidium atoms in an integrating sphere
Authors: Ma Hong-Yu  , Cheng Hua-Dong  , Zhang Wen-Zhuo  , Liu Liang  , Wang Yu-Zhu  ,   (1)中国科学院上海光学精密机械研究所量子光学重点实验室，上海  201800; (2)中国科学院上海光学精密机械研究所量子光学重点实验室，上海  201800；中国科学院研究生院,北京  100049
Published: December 2020

In this paper, the theory of atomic cooling in an integrating sphere is studied. During designing an integrating sphere system, the effects of the parameters of the sphere on the cooling, including the reflectivity of the material, the shape of the sphere and holes in the sphere have been considered carefully. The experiment of 87Rb atomic cooling in an integrating sphere was performed. The experimental results show that the atoms in the integrating sphere are cooled down evidently. And the relation between the detuning of the cooling laser and the absorption signal of cold atoms was measured.
The single attosecond pulse generated by atom exposed to two-color combined laser field
Authors: Ye Xiao-Liang  , Zhou Xiao-Xin  , Zhao Song-Feng  , Li Peng-Cheng  ,   (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重点实验室原子核理论研究中心,兰州  730000
Published: December 2020

By solving the time-dependent Schrdinger equation with split-operator method, we study the high harmonics of one-dimensional helium atom exposed to the two-color laser field composed of IR field and UV field, and analyze the characteristics of the attosecond pulse produced by the high-order harmonics. It is found that the width of the attosencond pulse is shortened by the increasing intensity of IR field in the combined laser field. By adjusting the time delay between two lasers, we can enhance the contribution of one of the electron trajectories and suppress that of the other. Thus we can obtain an isolated sub-100 as pulse.
L2—L∞ control for leader-following coordination of second-order multi-agent systems
Authors: Li Hui  , Lin Peng  , Zhang Chun-Xi  ,   北京航空航天大学，仪器科学与光电工程学院,北京  100083
Published: December 2020

This paper deals with L2—L∞ control for leader-following coordination of second-order multi-agent systems with external disturbance and time-delay on fixed topology. In practical applications, the peak value of the controlled output is often required to be within a certain range and the ranges of the position and the velocity are different, so we introduce the weighted coefficients for the controlled outputs of the position and the velocity separately. Then, we obtain a multi-agent system of the model.Based on the Lyapunov-Krasovskii theory, both networks with and without time-delay are analyzed for leader-following corrdination of the position vector and the velocity vector with the desired L2—L∞ performance. Furthermore, sufficient conditions in terms of bilinear matrix inequality are given to guarantee the consensus problems for the multi-agent systems with and without time-delay sparately. Finally,numerical simulations are provided to show the effectiveness of our strategies.
Treatment of Enterococcus faecalis bacteria using a plasma needle at atmospheric pressure
Authors: Zhang Xian-Hui  , Huang Jun  , Liu Xiao-Di  , Peng Lei  , Sun Yue  , Chen Wei  , Feng Ke-Cheng  , Yang Si-Ze  ,   (1)长春理工大学,长春  130022; (2)长春理工大学,长春  130022；中国科学院物理研究所,北京  100190; (3)口腔生物教研室,北京大学口腔医院,北京  100080; (4)中国科学院物理研究所,北京  100190
Published: December 2020

A Plasma Needle using a dielectric barrier discharge reactor at atmospheric pressure with a funnel-shaped nozzle was designed and realized. The preliminary characteristics of the plume and applications in the sterilization of Streptococcus mutans （S.mutans）, which is the most important microorganism causing dental caries, were presented in this paper. The reactor produced a cold plasma plume with temperature not higher than 315?K at 28?W. The effect of oxygen, which was injected downstream in the plasma afterglow region through a steel tube, was studied using its spectrum. The results show that addition of 26 mL·min-1 O2 led to the transport of atomic O further without significant effects on the jet length. The experiments show the best parameters are 15?W power, 01?m3·h-1 He with 25% O2 addition and separation of needle-to-sample 12?mm. It is found that ultraviolet rays, O，OH and He radicals can reach and act with S.mutans. To find critical radicals which are related to sterilization, we compareed the probe spectrum at atmosphereic pressure with that in agar.
Electronic properties of MgO nanotube clusters studied with density functional theory
Authors: Chen Liang  , Xu Can  , Zhang Xiao-Fang  ,   (1)兰州大学磁学与磁性材料教育部重点实验室，兰州  730000; (2)兰州大学磁学与磁性材料教育部重点实验室，兰州  730000；浙江林学院理学院，临安  311300
Published: December 2020

The averaged binding energy, energy gap, atomic charge and total charge density of the MgO nanotube clusters were calculated with B3LYP method at 6-31G（d） level. The calculations show that the everaged binding energy decreases approximately linearly with increasing coordination. The structural stability increases in company with length of MgO nanotube clusters, and the most stable structure is 3MR species. The charge transfer increases with length of MgO nanotube clusters, the averaged atomic charges of 2, 3 and 3 converge to 1298, 1270, 1306, respectively. Mixed covalent and ionic bonding property always exist in MgO nanoclusters.
An efficient algorithm of the electromagnetic dyadic Green’s function in a horizontal-layered anisotropic medium
Authors: Chen Gui-Bo  , Wang Hong-Nian  , Yao Jing-Jin  , Han Zi-Ye  , Yang Shou-Wen  ,   (1)吉林大学物理学院，长春  130021; (2)中国地质科学院地球物理地球化学勘察研究所，廊坊  065000
Published: December 2020

In this paper, we advance an efficient algorithm of electromagnetic spatial dyadic Greens function in a horizontal-layered anisotropic medium through high order window function and so on. First, we use the high order window function to transform the Sommerfeld integrals of dyadic Greens function into integrals along a generalized steep descent path. And we give a new and higher order of power series of expansion expression of Hankel transforms of the window function and an accurate formula of Lommel function so that the dyadic Greens function can be precisely computed either near or far from the transmitter. Then, we divide the integral path into a series of subintervals based on the zeros of Bessel function and compute integral per subinterval using an improved adaptive Gauss quadrature. Furthermore, an algorithm of the finite continued fraction expansion is used to sum up the integrals on each subinterval to greatly accelerate the convergence velocity of the numerical integration along the descent path. Finally, our numerical results validated the efficiency of the algorithm.
Calculation and analysis of the optical path difference of modified wollaston prism
Authors: Wu Hai-Ying  , Zhang Chun-Min  , Zhao Bao-Chang  , Li Ying-Cai  ,   (1)西安交通大学理学院,西安  710049; (2)中国科学院西安光学精密机械研究所空间光学实验室,西安  710068
Published: December 2020

The beam splitting and polarizing principle of modified Wollaston prism are presented. This paper analyses the propagation track of light wave in modified Wollaston prism by wave-normal-tracing method at random incidence angle and the formula of the path difference between e and o light waves are deduced. Computer simulations are carried out to give the curve of the optical path difference varying with incidence angle, incident azimuth angle, structural angle and wave length. The results will provide a theoretical basis for the study of polarization prisms and the development of polarization splitting apparatus.
The influence on the radiation characteristics of an amorphous nanocluster by introducing photonic crystals
Authors: Wang Hui-Qin  , Liu Zheng-Dong  ,   (1)南昌大学材料科学与工程学院,南昌  330031；南昌大学纳米技术研究中心,南昌  330047; (2)南昌大学材料科学与工程学院,南昌  330031；南昌大学物理实验中心,南昌  330031
Published: December 2020

The amorphous nanoclusters have short range order and long range disorder structures ordinarily. The radiation spectrum characteristics of an amorphous ZnO nanocluster are studied by using finite difference time domain method and the radiation spectrum shows as spontaneous emission. To control the spontaneous emission, photonic crystal is introduced to lead the radiation emission to the needed frequency. An easier and cheaper manufacture method is put forward in which the nanocluster should be inserted between two colloidal crystal films which self-assembled by uniform colloidal nanoparticles. According to this idea, a two dimensional system is constructed and the radiation characteristics of this system are simulated. The results show that the energy is controlled in this system effectively. This scheme can provide a new way to manufacture low threshold micro-lasers feasible for imbedding in optical integrated circuits.
Single-channel encryption of color image based on double-phase encoding
Authors: Yang Xiao-Ping  , Gao Li-Juan  , Wang Xiao-Lai  , Zhai Hong-Chen  , Wang Ming-Wei  ,   (1)南开大学现代光学研究所，教育部光电信息技术科学重点实验室，天津  300071; (2)天津理工大学电子信息与通信工程学院，天津  300191
Published: December 2020

In this paper, a new method of encrypting a color image in one channel based on double-phase encoding is presented. In this method, the colors of a color image are converted from RGB to HSI, so the I component can be used as the original image which could be encoded with double-phase. The kinoform of S is obtained by using double-random phase encryption and the H component can be used as the two phases. It is difficult to recover the S component if the phase keys are not available, because double-random phase encoding is robust to blind retrieval trials, so the security of the method proposed is guaranteed. Computer simulations are presented to illustrate the efficiency of this method.
The quantum interference of the two-mode cavity field spectra
Authors: Xia Qing-Feng  , Zhou Yu-Xin  , GaoYun-Feng  ,   聊城大学物理科学与信息工程学院，聊城  252059
Published: December 2020

The cavity field spectra of two-mode field both in the binomial state interacting with a two-level atom through intensity-dependent coupling in an ideal cavity is investigated. The results for the weak initial fields are calculated. The influence of the quantum interference on the cavity field spectra is discussed. Its found that when the difference of the initial two-mode field frequency Δ is larger than g （g is the coupling coefficient between atom and the field） the influence of the quantum interference on the spectra structure can be ignored, the system spectrum is only the superimposition of the two mode spectra. When Δ is smaller than g the quantum interference between the two-mode spectra is especially obvious. The quantum interference between the two-mode spectra should not be considered when the initial field is stronger.
Interfacial adhesive mechanism of confined liquid thin film of micro/nano-meter thickness
Authors: Xiong Yi  , Zhang Xiang-Jun  , Zhang Xiao-Hao  , Wen Shi-Zhu  ,   清华大学摩擦学国家重点实验室，北京  100084
Published: December 2020

Many insects and some animals, such as and crickets, tree frogs, can utilize a thin film of confined liquid between the pad and the smooth surface to facilitate climbing vertical walls and even walking on the ceiling. Our previous experiments based on a ball-disk microtribometer have revealed that a sudden unstable spreading or shrinking of the confined liquid film occurs when the volume reaches a critical value, which respectively corresponds to an unstable increasing or decreasing of interfacial adhesive force. This unstable behavior of the confined liquid film has important implications on the adhesion/releasing mechanism of wet bio-adhesive pad to or from the smooth surface. In this article, we highlight some of the switching mechanisms for capillary adhesion through theoritcal analysis and further experiments. It is found that, the unstable spreading and shrinking of confined liquid film is connected with the instability of the cantilever stiffness, and the maximum interfacial adhesive force decreases with the liquid volume and strongly depends on the film thickness of the central area. Inspired by these results, strategies for a bio-adhesive pad to realize `switchable' adhesive mechanism is analyzed, which will shed light on the design and control of a biomimetic adhesive pad.
Magnetically tunable liquid crystal terahertz switch based on Bragg fiber
Authors: Wu Ben  , Zhang Hui  , Zhu Liang-Dong  , Guo Peng  , Wang Qian  , Gao Run-Mei  , Chang Sheng-Jiang  ,   (1)桂林工学院数理系,桂林  541004; (2)南开大学现代光学研究所,光电信息技术科学教育部重点实验室,天津  300071; (3)天津市医药科学研究所,天津  300020
Published: December 2020

A novel magnetically tunable liquid crystal terahertz switch is designed to reduce the coupling loss. The main structure of the switch is the hollow-core Bragg fiber with its cladding constructed by periodically setting of high density polyethylene and nematic liquid crystal E7 The refractive index of the E7 can be changed by the application of outside magnetic field and thus alter the loss property of the Bragg fiber dramatically to achieve its function as a switch. The main advantage of this switch is that it can eliminate the loss of coupling with fibers,and what is more,this switch can select the basic mode and is easy to be controlled. This article uses the finite element method to obtain the parameter of the switch and the simulated value of the extinction ratio reaches 2634 dB.
Simulation of hydrogen adsorption in molecular sieves
Authors: Dai Wei  , Luo Jiang-Shan  , Tang Yong-Jian  , Wang Chao-Yang  , Chen Shan-Jun  , Sun Wei-Guo  ,   (1)四川大学原子与分子物理研究所，成都  610065; (2)中国工程物理研究院激光聚变研究中心，绵阳  621900; (3)中国工程物理研究院激光聚变研究中心，绵阳  621900；四川大学原子与分子物理研究所，成都  610065
Published: December 2020

The adsorption of hydrogen in AFS and AST molecular sieves are studied using grand canonical Monte Carlo （GCMC） technique in this paper. Dubinin-Astakhov（DA）method was employed to analyzed the physical reasons which affect the storage of hydrogen. The work in this paper facilitates direct rational design and synthesis of the materials which apply to storage of hydrogen, and provide a powerful theoretical support to improve the hydrogen storage capability of the materials.
Characteristic study of maximum modal gain of p-doped 1.3 μm InAs/GaAs quantum dot lasers
Authors: Ji Hai-Ming  , Cao Yu-Lian  , Yang Tao  , Ma Wen-Quan  , Cao Qing  , Chen Liang-Hui  ,   中国科学院半导体研究所纳米光电子实验室，北京  100083
Published: December 2020

We report an experimental and theoretical study of maximum modal gain of p-doped 13 μm InAs/GaAs quantum dot （QD） lasers. The maximum modal gain of the QD laser with five stacks of QDs is as high as 175 cm-1, which is the same as that of the undoped laser with identical structures. The expression of the maximum modal gain is derived and it is indicated that p-doping has no effect to the maximum modal gain.We theoretically calculated the maximum modal gain of the QD lasers and the result is in a good agreement with the experimental data. Furthermore, QDs with lower height or smaller aspect ratio are beneficial to achieving a greater maximum modal gain that leads to lower threshold current density and higher differential modal gain, which is good for the application of p-doped 13 μm InAs/GaAs QD lasers in optical communications systems.
First-principles study of the adsorption energy and work function of oxygen adsorption on Ni(111) surface
Authors: Xu Gui-Gui  , Wu Qing-Yun  , Zhang Jian-Min  , Chen Zhi-Gao  , Huang Zhi-Gao  ,   福建师范大学物理与光电信息科技学院，福州  350007
Published: December 2020

The adsorption of atomic oxygen on the Ni（111） surface has been systematically investigated through first-principles DFT-GGA methods in wide ranges of coverage. It was found that the fcc hollow site is the energetically most favorable for the whole coverage range considered. The adsorption energy decreases with the coverage θ，while the work function increases linearly with the coverage.It can be also concluded from analysis of the electron density and projected density of states that the electron transfer from the substrate （Ni atoms） to the O atom gives rise to the appearance of a dipole moment, which results in a large increase in the work function. The O—Ni interaction between Ni 3d and O 2p orbitals results in the formation of bonding and antibonding states, while the antibonding states are hardly occupied. Therefore, the bonding interaction between O and Ni is stonger, and the adsorption energy is larger.
Simulation and experimental investigation of recessed-gate AlGaN/GaN HEMT
Authors: Wang Chong  , Quan Si  , Zhang Jin-Feng  , Hao Yue  , Feng Qian  , Chen Jun-Feng  ,   西安电子科技大学微电子研究所，西安  710071；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

The effect of recessed-gate depth on device characteristics was analyzed. The device characteristics with different recessed-gate depth were simulated by using SILVACO and the variation of saturation current, maximum conductance and threshold with different recessed-gate depth were obtained. With increasing recessed-gate depth, the saturation current reduces and maximum conductance increases and the threshold shifts to positive direction of X-axis. High electron mobility transistors of AlGaN/GaN heterostructure grown on sapphire substrates with different recessed-gate depth were fabricated. The simulation of different recessed-gate depth device characteristics were validated by comparing experiments with the simulation results. The discrepancies between simulation and experiment were analyzed in the aspects of etching damage and interface states.