bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of external magnetic field on ion energy density of collisional radio-frequency sheath
Authors: Zou Xiu  , Zou Bin-Yan  , Liu Hui-Ping  ,   大连交通大学理学院，大连  116028
Published: December 2020

A two-fluid model is proposed to describe the collisional radio-frequency plasma sheath in a magnetic field, and the ion energy distribution incident on the radio-frequency sheath biased electrode is numerically investigated. The simulation results reveal that the external magnetic field dominates the ion flux and energy distribution of the sheath. The ion energy can be transferred between the perpendicular direction and parallel direction under the action of magnetic field.
Molecular dynamics simulation of helium cluster growth in titanium
Authors: Wang Jun  , Hou Qing  ,   四川大学原子核科学技术研究所辐射物理及技术教育部重点实验室，成都  610064
Published: December 2020

The growth of helium cluster in titanium crystals at room temperature has been simulated detailedly by means of molecular dynamics. The mechanism of helium cluster growth in metal materials has been investigated from the viewpoint of energy. It is found that, as the helium cluster grows, dislocation loops are formed around the cluster and the binding energy of each additional helium atom to these clusters tends to decrease. However, at certain point in the growth process, the defects escape rapidly and the binding energy increases, helping the further growth of the helium cluster. As more helium atoms are introduced, the shape of the helium cluster is transformed gradually to a prismatic morphology from the irregular morphology and its thickness is always observed to be about 1.2 nm, without any obvious variation with degree of helium filling.
Effect of quantum confinement on acceptor state lifetime in Be δ doped GaAs/AlAs multiple quantum wells
Authors: Song Ying-Xin  , Zheng Wei-Min  , Liu Jing  , Chu Ning-Ning  , Li Su-Mei  ,   山东大学威海分校空间科学与物理学院，威海  264209
Published: December 2020

Using far-infrared time-resolved spectroscopy，we have investigated the effect of quantum-well confinement on the lifetime of shallow acceptor states in GaAs/AlAs multiple quantum wells with Be δ-doping. Low-temperature far-infrared absorption measurements clearly show three principal absorption lines due to transitions of Be acceptor states from the ground state to the first three odd-parity excited states，respectively. It is found that the lifetime of excited states is monotonically reduced with decreasing quantum-well width，from 350 ps in bulk to 55 ps in a 100 ? well. We suggest that the effect of quantum-well confinement on zone-fold acoustic-phonon modes increases the intra-acceptor scattering rate of acoustic-phonon-assisted relaxation.
The effect of nickel ions on structure and conductivity of DNA
Authors: Li Ke  , Dong Rui-Xin  , Ban Ge  , Han Hong-Wen  , Su Wei  , Yan Xun-Ling  ,   聊城大学物理科学与信息工程学院，聊城  252059
Published: December 2020

The modified M-DNA molecular wires were prepared by adding nickel ions of low concentration to the calf thymus DNA in alkaline solution. And we investigated the conductivity of single DNA and M-DNA molecules. The results indicated that the M-DNA and the B-DNA show semiconductor properties. But the conductivity of M-DNA is higher than that of the B-DNA，and the voltage gap is smaller. When the concentration of nickel ions is more than 0.1 m mol/L，the conductance of DNA does not change with the nickel concentration. In addition，the right to left-handed DNA transition was realized by adding nickel ions of appropriate concentration to the calf thymus DNA in neutral solution and the structure of left handed Z-DNA was observed by STM. The result showed that the major and minor grooves are obvious，unwinding and disordering regions can be found in the Z-DNA. The conductivity of left-handed DNA was much lower than that of the B-DNA. The conductivity relationship of B-DNA，M-DNA and Z-DNA is GM-DNA>GB-DNA>GZ-DNA. The UV absorption spectra and the Raman spectra indicated that the transition of B-Z DNA appears when the concentration of nickel ions is about 1.7 mol/L.
The magnetization of antiferrmagnetic layer and the spin wave in the system of the exchange bias
Authors: Pan Jing  , Zhou Lan  , Hu Jing-Guo  ,   扬州大学物理科学与技术学院，扬州  225002
Published: December 2020

Using a method of free energy minimization，the spin wave of ferromagnetic （FM）/antiferromagnetic （AFM） bilayers was investigated，in which the net magnetization of AFM layer has been considered. In this model，the thin FM layer is taken to be a single crystal with cubic and uniaxial magnetocrystalline anisotropies，but AFM layer has only single uniaxial magnetocrystalline anisotropy and its thickness is finite. Numerical calculation shows that there are two modes of spin waves：namely the acoustic mode and the optical mode. Moreover, only when there is net magnetization of AFM layer can the optical mode be observed. There are two branches of FMR curves，i.e. the branches of weak and strong external field，which are distinguished by the critical field，while the critical field depends on the exchange bias field，the magnetization and thickness of AFM layer. The effect of the exchange bias field on the optical mode is more obvious than that on the acoustic mode，while the effects groduced by net magnetization and thickness of AFM layer cant be distinguished. However，when the net magnetization of AFM layer is neglected，only an acoustic mode is observed.
The structure, magnetic properties, and positron annihilation spectra of Tb2AlFe16-xMnx compounds
Authors: Hao Yan-Ming  , Yan Da-Li  , Fu Bin  , Wang Li-Qun  , Hao Xiao-Peng  , Wang Bao-Yi  ,   (1)天津科技大学理学院物理部，天津  300222; (2)天津师范大学物理系，天津  300384; (3)中国科学院高能物理研究所核分析技术重点实验室，北京  100049
Published: December 2020

The structural and magnetic properties have been investigated by means of X-ray diffraction, magnetization measurements, and positron annihilation technique. The X-ray diffraction shows that the Tb2AlFe16-xMnx （x=1—8） compounds have a hexagonal Th2Ni17-type structure. The positron annihilation spectra show that Mn substitution for Fe has the ferromagnetic interaction decreased, and that there exists a strong magnetoelastic effect in Tb2AlFe16-xMnx compound. The magnetization measurement shows that the Curie temperature and the spontaneous magnetization of Tb2AlFe16-xMnx compounds decrease rapidly with increasing x.
Modulated free carrier absorption characterization of semiconductor wafers by frequency scans at different pump-to-probe separations
Authors: Li Wei  , Li Bin-Cheng  ,   (1)中国科学院光束控制重点实验室，中国科学院光电技术研究所，成都  610209; (2)中国科学院光束控制重点实验室，中国科学院光电技术研究所，成都  610209；中国科学院研究生院，北京  100049
Published: December 2020

Based on a three-dimensional modulated free carrier absorption （MFCA） model，simulation was performed to investigate the dependences of MFCA amplitude and phase on the electronic transport properties （the carrier lifetime，the carrier diffusivity，and the front surface recombination velocity） of semiconductor wafers at different pump-to-probe separations and different modulation frequencies. Experiments were performed with a silicon wafer，in which amplitude and phase were recorded as functions of modulation frequencies at several different two-beam separations. The electronic transport properties of semiconductor wafers were determined simultaneously via multi-parameter fitting procedure. These results showed that the method is capable of improving the measurement precision of the simultaneous multi-parameter determination of transport properties.
Deposition of orthorhombic boron nitride films by plasma-enhanced pulsed laser deposition
Authors: Li Wei-Qing  ,   天津大学理学院现代材料物理研究所，天津市低维功能材料物理与制备技术重点实验室，天津  300072
Published: December 2020

In this paper, high quality orthorhombic boron nitride （o-BN） films were prepared on Si（100） substrate by plasma-enhanced pulsed laser deposition （PE-PLD） for the first time. The films were characterized by Fourier transform infrared （FTIR） spectroscopy，glancing-angle X-ray diffraction （XRD） and atomic force microscopic （AFM）. In the FTIR spectrum of the film, we can see three characteristic peaks around 1189cm-1, 1585cm-1 and 1450cm-1 of o-BN. The diffraction peaks ［111］, ［020］, ［021］, ［310］ and ［243］ all appeared in XRD, especially ［243］ and ［310］ crystal plane diffraction were very strong. The surface morphology was closely observed by AFM photograph.
Absorption properties of micro-plasma sprayed carbon nanotube-nanostructure Al2O3-TiO2 composite coatings
Authors: Hua Shao-Chun  , Wang Han-Gong  , Wang Liu-Ying  , Liu Gu  , Zhao Rui-Xing  , Yao Jian-Xun  ,   第二炮兵工程学院,西安  710025
Published: December 2020

Carbon nanotube-nanostructure Al2O3-TiO2 composite powders were prepared by mixing carbon nanotubes with nanostructure Al2O3-TiO2 ceramics in an ultrasonic bath. Electromagnetic parameters of the composite material were determined at 2—18GHz. The experimental results show that the complex permititivity and loss tangent of the dielectric increase as the weight content of carbon nanotubes increases. The minimum absorption value increases firstly and then dtcreases and the resonance frequency gradually moves to the low frequency and with increase of the weight content of carbon nanotubes and the thickness of composite coatings. Carbon nanotube 7wt%-nanostructure Al2O3-TiO2 composite coatings were deposited by micro-plasma spraying. The minimum absorption value for 1.5mm thick composite coatings was -26.3dB. The frequency range for absorption value less than -10dB of 2.0mm thick composite coatings was 3.60GHz. When the 1.0mm thick composite coating was heated to 500℃, the minimum high temperature absorption value was -12.2dB and the frequency range for absorption value less than -10dB was 2.00GHz. There is a linear relationship between experimental and theoretical thickness of composite coatings:d=0.898D+0.515, where D is the experimental thickness and d is the theoretical thickness.
Directional dendrite growth of SCN-3wt% H2O under shear flow
Authors: Wang Jian-Yuan  , Chen Chang-Le  , Zhai Wei  , Jin Ke-Xin  ,   西北工业大学理学院,西安  710072
Published: December 2020

Directional solidification of SCN-3wt% H2O was carried out under externally imposed parallel shear flow, and the growth characteristics of dendritic tips, primary arms and secondary arms were investigated. A bright band related to solute boundary layer along the dendritic tip is observed for the first time. It was confirmed that the left-right symmetry of the dendritic tip is broken up by the shear flow, with the dendritic tip tilting toward the upstream side. The tilting angle increases with the pulling rate. Compared with the case of static condition, the primary spacing becomes lager under shear flow, and this is due to the coupling effect of flow and solute fields. The growth of secondary arm is promoted at the upstream side whereas greatly restrained at the downstream side, which is caused by the circumfluence among dendrites produced by force flow.
XRD studies on the electrode materials in the charge-discharge process of a graphite/Li（Ni1/3Co1/3Mn1/3）O2 battery
Authors: Li Jia  , Yang Chuan-Zheng  , Zhang Xi-Gui  , Zhang Jian  , Xia Bao-Jia  ,   中国科学院上海微系统与信息技术研究所，上海  200050
Published: December 2020

Structure transformation and microstructure of the electrode active materials in a graphite / Li （Ni1/3Co1/3Mn1/3）O2 lithium ion battery during charge-discharge process have been studied by XRD. It is found that the lattice parameter of Li （Ni1/3Co1/3Mn1/3）O2, a and c, decrease and increase respectively. Its micro-strain ε and diffraction intensity ratio, I104/I101 and I012/I101, increases and decrease respectively, because Li atoms de-intercalate out of the crystal lattice of LiMO2. Meanwhile, the lattice parameter, a and c, micro-strain ε and stacking disorder P of 2H-graphite all increase, becausing Li atoms to intercalate into 2H-graphite.During charge process, Li atoms occupying （000） sites may preferentially de-intercalate from LiMO2 crystal lattice, and subsequently the Li atoms occupying （2/3 1/3 1/3）and（1/3 2/3 2/3）sites de-intercalate from LiMO2. When intercalating into 2H-graphite, Li atoms preferentially occupy interstitial sites between C atom hexagonal net planes. When the stacking disorder degree reaches a given value, 3R-graphite phase may separate out gradually. When the battery has been fully charged or over charged, LiC12 and LiC6 phases can be formed. During discharge process, intercalation and de-intercalation behaviors of Li atoms are reversed. Li atoms may de-intercalate preferentially from interstitial sites of 2H-graphite and intercalate preferentially into （000） sites of LiMO2 crystal lattice. But these processes are not fully reversible.
Numerical calculation of the response of the south China sea to typhoon imbudo
Authors: Cui Hong  , Zhang Shu-Wen  , Wang Qing-Ye  ,   (1)广东海洋大学海洋与气象学院，南海海洋环境研究所，湛江  524088; (2)中国科学院海洋研究所，青岛  266071；中国科学院研究生院，北京  100049
Published: December 2020

The response of the South China Sea （SCS） to Typhoon Imbudo was examined using POM model. The results indicated that SST decreased by 2—6℃with a rightward-biased response as Typhoon Imbudo passed across the SCS. Due to a strong mixing process, the mixed layer （ML） depth deepened as much as 10—60m and ML heat budget lost 824.78W/m2, which was dominated by the vertical mixing. By the response of upper ML heat transport, the temperature below the ML increased and oscillated near the inertial period. Furthermore, strong inertial currents were generated by the storm with the max currents up to 1.4m/s in the upper ML.
Zero-broadening slow and fast light using an optimized Brillouin comb gain for arbitrary periodic signals
Authors: Zheng Di  , Pan Wei  , Yan Lian-Shan  , Luo Bin  , Zou Xi-Hua  , Jiang Ning  , Ma Ya-Nan  ,   西南交通大学信息科学与技术学院，成都  610031
Published: December 2020

Based on the theoretical analysis of the conditions of the fast or slow light without distortion for arbitrary signal, a universal formula of an optimized Brillouin comb gain is obtained in accordance with the spectrum characteristics of the periodic signal. According to the amount of delay or advancement required, each Brillouin gain intensity and frequency detuning between Brillouin gain peak and the corresponding harmonic frequency of periodic signal can be found conveniently using this universal formula, then the whole Brillouin comb gain is identified. Numerical calculation for sinusoidal signal, Gaussian periodic signal and square periodic signal is performed. The results show that zero-broadening slow and fast light is achieved using this optimized Brillouin comb gain for the three types of periodic signals, and the validity of the universal formula is proved. Moreover, the magnitude of the delay or advancement can be tuned continuously by adjusting the Brillouin gain intensity and frequency detuning.
Two-dimensional Kummer-Gaussian soliton clusters in strongly nonlocal nonlinear media
Authors: Xu Si-Liu  , Liu Hui-Ping  , Yi Lin  ,   (1)华中科技大学物理学院,武汉  430074; (2)华中科技大学物理学院,武汉  430074；咸宁学院物理系,咸宁  437100
Published: December 2020

We solve the two-dimensional strongly nonlocal nonlinear Schrdinger equation in polar coordinates. An exact analytical solution of self-similar waves, namely Kummer-Gaussian soliton clusters, is obtained. Numerical simulations confirm the validity of the analytical solutions. It is shown that the nonlocal optical spacial solitons have large phase shift.
Power controlled short-range interactions between strongly nonlocal spatial soliton
Authors: Zheng Ya-Jian  , Xuan Wen-Tao  , Lu Da-Quan  , Ouyang Shi-Gen  , Hu Wei  , Guo Qi  ,   华南师范大学光子信息技术广东省高校重点实验室，广州  510006
Published: December 2020

We investigate the power controlled short-range interactions between spacial optical solitons in the strongly nonlocal nonlinear media. For the short-range interactions, the trajectory of mass center of solitons will deflect because of the phase difference under the condition of momentum conservation. We verify by experiment that the degree of deflection depends on the ratio of the power of two solitons, and the case of equal power corresponds to the maximum deflection. Using the characteristics of power control on the interaction between solitons, we measure the photic-induced response time of nematic liquid crystals, and find that it is much shorter than the bias-voltage-induced response time.
An experimental investigation of planar nearfield acoustic holography using pressure and particle velocity measurements
Authors: Bi Chuan-Xing  , Zhang Yong-Bin  , Xu Liang  , Chen Xin-Zhao  ,   合肥工业大学噪声振动工程研究所,合肥  230009
Published: December 2020

In the conventional nearfield acoustic holography （NAH）, only the pressure or particle velocity is used as the input quantity, and it cannot separate the waves from the two sides of the hologram surface. Therefore, all sources are assumed to be on one side of the hologram surface, i.e. the sound field is assumed to be free. This assumption limits the practical applications of NAH. In the NAH using pressure and particle velocity measurements, both pressure and particle velocity are used as the input quantities. By establishing and solving the coupling relationship on the hologram surface between the waves from the two sides of the hologram surface, the waves from the two sides can be separated. On the basis of the previous studies on sound field separation techniques and based on the Euler formula and the finite difference approximation technique, a new theoretical formula of NAH using pressure and particle velocity measurements is given, and then an experiment is performed to validate the method.
Effects of the microwave magnetic field and oblique incident microwave on multipactor discharge on a dielectric surface
Authors: Cai Li-Bing  , Wang Jian-Guo  ,   (1)西北核技术研究所,西安  710024; (2)西北核技术研究所,西安  710024；西安交通大学电子与信息工程学院，西安  710049
Published: December 2020

We analyze, separately, the effects of the microwave magnetic field and the oblique microwave field on multipactor discharge on a dielectric surface. Using particle-in-cell/Monte Carlo simulation, we obtain the temporal evolution of the number of electrons, direct current electric field, mean kinetic energy of electrons，and power deposited in the dielectric in the cases of the microwave magnetic field and the oblique microwave field. The numerical results show that the oblique microwave field and the microwave magnetic field can significantly affect the mean kinetic energy of electrons, but do not qualitatively change the number of electrons and the power deposited in the dielectric, so the microwave magnetic field and the oblique microwave field do not significantly affect the multipactor.
Structure and luminescence properties of Sr4Al14O25:Eu2+, Dy3+ by Ca2+ doping
Authors: Xie Wei  , Wang Yin-Hai  , Hu Yi-Hua  , Wu Hao-Yi  , Deng Liu-Yong  , Liao Feng  ,   广东工业大学物理与光电工程学院，广州  510006
Published: December 2020

The rare-earth doped strontium aluminate phosphors SrxCa4-xAl14O25:Eu2+,Dy3+（x＝0，0.8，1.6，2.4，3.2，4） were synthesized by a high temperature solid-state reaction method. The X-ray diffraction studies show that phase of the phosphors is orthorhombic Sr4Al14O25 for x4O7 for x > 2.4. The results indicate that the phase structure of the samples changes from Sr4Al14O25 to CaAl4O7 when the value of x changes from 0 to 4. In addition, a blue shift was found in the emission spectra due to the change in nature of the Eu2+ surroundings. The decay characteristics show that the phosphor samples with different Ca2+ contents have different afterglow time, and the afterglow time also changes with the value of x. The measurement of thermoluminescence reveals that the trap depth of the phosphor samples with different Ca2+ contents is different. The samples with deeper traps have longer afterglow time.
The dispersion relation for surface plasmon at a metal-Kerr nonlinear medium interface
Authors: Liu Bing-Can  , Lu Zhi-Xin  , Yu Li  ,   (1)北京邮电大学理学院,北京  100876; (2)北京邮电大学理学院,北京  100876；装甲兵工程学院基础部,北京  100072
Published: December 2020

The dispersion relation of transverse magnetic（TM） wave and transverse electric（TE） wave for surface plasmon at a metal-Kerr nonlinear medium interface are analyzed based on the Maxwell equations and the boundary conditions. The dispersion relation of TM wave is complex, due to the nonlinearity, and it has a dielectric coefficient and intensity-dependent expression. However, the TE wave does not exist at this interface as in the linear case.
Effect of deposition rate on the scaling behavior of microcrystalline silicon films prepared by very high frequency-plasma enhanced chemical vapor deposition
Authors: Ding Yan-Li  , Zhu Zhi-Li  , Gu Jin-Hua  , Shi Xin-Wei  , Yang Shi-E  , Gao Xiao-Yong  , Chen Yong-Sheng  , Lu Jing-Xiao  ,   郑州大学物理工程学院,材料物理教育部重点实验室，郑州  450052
Published: December 2020

Three sets of hydrogenated microcrystalline silicon （μc-Si:H） films for different deposition time were prepared by very high frequency-plasma enhanced chemical vapor deposition with different deposition rates. The surface roughness evolution of μc-Si:H has been investigated using spectroscopic ellipsometry. For films with the deposition rate of 0.08 nm/s and 0.24 nm/s, the surface roughness of films changes a little, and the growth exponent β is about 0.20. Similar β values ascribed to the adatoms have enough time to move to the site with lower energy under lower deposition rate. However, when the deposition rate increases to 0.66 nm/s, the surface roughness of films increases obviously, and the exponent β is about 0.81, which is much higher than 0.5 for zero diffusion limit in the scaling theory. The growth mode of high-rate deposited μc-Si:H is clearly different from that of lower-rate deposited μc-Si:H. This is due to the fact that the adatoms have no enough time to diffuse before being covered by the radicals of the next layer under high deposition rate, which decreases the surface diffusion of the adatom, and therefore increases the film surface roughening which results in a larger β. The case of β>0.5 is related to the shadowing effect.
Heterojunction organic solar cells with Rubrene as electron transporting layer
Authors: Li Yan-Wu  , Liu Peng-Yi  , Hou Lin-Tao  , Wu Bing  ,   暨南大学物理学系，广州  510632
Published: December 2020

Organic solar cells with structure of ITO/MoO3（5 nm）/Rubrene（50 nm）/C60（45 nm）/Rubrene（0, 3, 5.5, 9.5 nm）/Al（130 nm） were prepared. The rubrene layer near the Al cathode was used as the electron transporting layer. Compared with that of the control device without the electron transporting layer, the open circuit voltage, fill factor and power conversion efficiency of the device with 5.5 nm rubrene layer were increased from 0.68 V, 0.488, 0.315% to 0.86 V, 0.574, 0.490%, respectively. The analysis of the experimental results shows that when hot Al atoms are directly deposited on C60 layer, the C60 layer is undermined and a high work function is formed, which leads to a weaker built-in electric field and a poorer performance. When the rubrene layer is inserted, a significant improvement in device performance is achieved due to the formation of defect states in rubrene layer during Al deposition. Further experimental results of single-electron devices show that energy levels of the defect states are lower than that of the lowest unoccupied molecular orbital of C60.
Photoluminescence of diluted Mg doped ZnO thin films and band-gap change mechanisms
Authors: Gao Li  , Zhang Jian-Min  ,   陕西师范大学物理学与信息技术学院，西安  710062
Published: December 2020

ZnO and ZnO thin films doped with different Mg contents （0.81at%,2.43at% and 4.05at%） were fabricated by radio frequency-magnetron sputtering （RF-MS） on glass substrates at 450 ℃. The microstructure, photoluminescence （PL）, optical and electrical properties were investigated. The results show that ZnO and diluted Mg doped ZnO thin films present a hexagonal wurtzite structure with high crystal quality. In the short wavelength side of near band emission （NBE）, a high energy emission band for 0.81at% and 2.43at% Mg doped thin films occurs together with NBE. The increasingly high energy band peak gradually covers the NBE peak with Mg doping increasing to 4.05at%. It is suggested that the energy of the electrons near the substituted Mg2+ increases, and these electrons occupy a higher energy level. However, the energy gap between conduction band and valance band still exists because the electrons energy near the un-substituted Zn2+ does not change. With the increasing doped Mg content, electrons in the higher energy level increase and predominate. Therefore, the reason for the increase in the band gap of Mg doped ZnO thin films can be attributed to the increase in the energy of electrons after Mg doping, together with the Burstein-Moss effect. Incidentally, all films exhibit a high average optical transmission （≥85%）. The optical band gap of Mg doped ZnO thin films increases with the increasing Mg doping content and changes from 3.36 to 3.52 eV. The resistivity of the Mg doped films are 2.2×10-3, 3.4×10-3 and 8.1×10-3 Ω·cm for 0.81at%, 2.43at% and 4.05at% Mg contents, respectively.
Properties of La and V codoped Bi4Ti3O12 thin film prepared by sol-gel method
Authors: Li Jian-Jun  , Yu Jun  , Li Jia  , Wang Meng  , Li Yu-Bin  , Wu Yun-Yi  , Gao Jun-Xiong  , Wang Yun-Bo  ,   华中科技大学电子科学与技术系，武汉  430074
Published: December 2020

Bi4Ti3O12（BIT） and Bi3.25La0.75Ti2.97V0.03O12（BLTV） thin films were fabricated on the Pt/TiO2/SiO2/p-Si（100） substrate using sol-gel method. The effect of La and V codoping on the structural and electrical properties of BIT thin films was investigated. BIT thin film exhibits predominantly c-axis orientation while BLTV thin film shows random orientation. Raman spectroscopy shows that TiO6 （or VO6） symmetry decreases and Ti—O （or V—O） hybridization increases with V substitution. The residual polarization of BLTV thin film is 25.4 μC/cm2, which is larger than that of BIT thin film （9.2 μC/cm2）. BLTV thin film also shows excellent fatigue endurance and low leakage current characteristics, which implies the oxygen vacancies are suppressed by La and V codoping in the thin films.
The fluorescence and thermoluminescence characteristics of α-Al2O3 transparent ceramics
Authors: Zhang Bin  , Zhang Hao-Jia  , Yang Qiu-Hong  , Lu Shen-Zhou  ,   上海大学电子信息材料系，上海  200072
Published: December 2020

Transparent polycrystalline α-Al2O3 ceramics were fabricated by conventional solid-state processing with MgO as additive. The absorption, excitation, emission spectra and thermoluminescence of α-Al2O3 transparent ceramics were investigated. There are two characteristic absorptions, one is centered at 192 nm, and the other at from 230 to 250 nm, which are caused by F+ and F color centers, respectively. There is one obvious emission peak located at 410 nm. Based on the excitation spectra, it is shown that the emission peaks are caused by the absorption of F+ and F color centers. The thermoluminescence curves show three peaks centered at 368, 456 and 614 K, respectively. The peak centered at 456 K may be caused by F and F+ centers.
System errors of a 256-element high intensity focused ultrasound phased array and precise control of multi-focus patterns
Authors: Xu Feng  , Lu Ming-Zhu  , Wan Ming-Xi  , Fang Fei  ,   西安交通大学生物医学信息工程教育部重点实验室，西安  710049
Published: December 2020

A comprehensive error analysis is carried out for a 256-element annular spherical-section phased array when used for synthesizing three\|dimensional multi-focus acoustic fields. The influence of array excitation errors on field patterns is summarized for both amplitude and phase errors. References to the design of driving module are provided for phased array with hundreds of elements. The simulation results show that the phased array with hundreds of elements has a robust ability of acoustic field synthesizing. Five-bit digitalization of phase signal can ensure the validity of the abstained acoustic fields. The array excitation errors affect the focal energy distribution mostly. The effect of amplitude errors can be weakened by reducing the error ratio through increasing the overall excitation energy.
Method for measuring the particle velocity using plasma produced by hypervelocity impact
Authors: Li Hong-Wei  , Han Jian-Wei  , Huang Jian-Guo  , Cai Ming-Hui  , Li Xiao-Yin  , Gao Zhu-Xiu  ,   (1)中国科学院空间科学与应用研究中心，北京  100190; (2)中国科学院空间科学与应用研究中心，北京  100190；中国科学院研究生院，北京  100049
Published: December 2020

Hypervelocity impact can produce instantaneous plasma during the impact． Through two kind of sensor designed in this paper to collect the plasma to attain the arriving time of the particle, we use the time of flight method to obtain the velocity of the particle． During the elementary experiment in the plasma drag particle accelerator, the impact signal was captured and the measurement of the particle velocity was achieved．The experiment result proves that this method has a high precision in time survey and a high signal to noise ratio．
A new algorithm for computation of two-dimensional unstable manifolds and its applications
Authors: Li Qing-Du  , Yang Xiao-Song  ,   (1)重庆邮电大学系统科学研究中心非线性系统研究所，重庆  400065; (2)重庆邮电大学系统科学研究中心非线性系统研究所，重庆  400065；华中科技大学数学系，武汉  430074
Published: December 2020

This paper proposes a new algorithm for computing two-dimensional （un）stable manifolds in time continuous systems. With this algorithm, one can not only get a picture of a manifold efficiently, but also has many information of its every point, which are very useful for investigating the global dynamics of a system geometrically, such as features of stability region, evolution of the system flow and so on. The algorithm is mainly by finding many well distributed trajectories by solving initial value problems. An example on Lorenz system suggests this algorithm is very convenient. In addition, we study the chaotic dynamic of a three-dimensional neural network by detecting a heteroclinic orbit.
Exact dynamic modeling of a spatial flexible beam with large overall motion and nonlinear deformation
Authors: He Xing-Suo  , Deng Feng-Yan  , Wang Rui  ,   西北工业大学工程力学系，西安  710072
Published: December 2020

In this paper, the dynamic modeling theory of a spatial flexible beam, which undergoes large overall motion and nonlinear deformation, is investigated. As we know, in spacecraft and space station, there are a lot of flexible appendices so the dynamic modeling of a flexible beam is essential. Yet the existing models, in our opinion, lack several important coupling terms. This paper supplies these important coupling terms. Based on the new approach of deformation of fully geometrically nonlinear beam model developed，the finite element method is used for the system discretization and the coupling dynamic equations of flexible beam are obtained by Lagrange’s equations. The complete expression of stiffness matrix and all coupling terms are included in the dynamic equations. The second order coupling terms between rigid large overall motion, arc length stretch, lateral flexible deformation kinematics and torsional deformation terms are included in the present exact coupling model to expand the theory of one-order coupling model. The dynamic modeling method in this paper is of theoretical significance and has reference value for the rigid-flexible coupling system dynamic investigation .
Entanglement evolution between atoms in the non-degenerate two photons Tavis-Cummings model in resonance and non-resonance cases
Authors: Zhang Guo-Feng  , Bu Jing-Jing  ,   北京航空航天大学物理科学与核能工程学院物理系，北京 100191
Published: December 2020

The entanglement character between a two-level atom and a two-mode field as well as two-level atoms in the non-degenerate two photons Tavis-Cummings model in the resonance and non-resonance cases have been investigated, and the analytical expression about entanglement is obtained. Based on two kinds of initial states, the effects of field frequency, atomic frequency and dipole-dipole coupling between atoms on the entanglement are shown in detail. The cases of resonance and non-resonance are compared.
Fault tolerant control of master-slave synchronization for a class of chaos systems with multiple time-delays
Authors: Zhang Hua-Guang  , Ma Da-Zhong  , Wang Zhan-Shan  , Feng Jian  ,   东北大学信息科学与工程学院，沈阳  110004
Published: December 2020

The problem of master-slave fault tolerant synchronization for a class of chaotic systems with multiple time-delays is considered. A fault tolerant synchronization is designed for a fault occuring in chaotic systems. Whether the fault happens in the chaotic systems or not，the synchronization method not only guarantees that the error system is globally asymptotically stable，but also satisfies a prescribed performance level. The fault tolerant controller contains two parts：the state feedback controller and fault compensator. A delay-dependent condition based on linear matrix inequality (LMI) is proposed for fault tolerant controller. The effectiveness of proposed design method is demonstrated by a simulation example.
Instantaneous radiation energy flux and instantaneous radiation power of dynamic spherically symmetric black holes
Authors: Meng Qing-Miao  , Jiang Ji-Jian  , Li Chuan-An  ,   菏泽学院物理系,菏泽 274015
Published: December 2020

By the thin film model and the local thermal equilibrium assumption, the instantaneous radiation power and instantaneous radiation energy flux near the event horizon of the dynamic spherically symmetric black hole have been studied. When the cut-off distance η takes a fixed value, the following results can be obtained. For Vaidya black hole, its instantaneous radiation energy flux of the scalar field near the event horizon is related to both the black hole mass and the change rate of the event horizon. But its instantaneous radiation power is only related to the change rate of the horizon. For Vaidya-Bonner black hole, the instantaneous radiation power and instantaneous radiation energy flux are all related to the mass, the charge of the black hole and the change rate of the event horizon. These results show that the gravitational field, electromagnetic field and the change of the horizon will all affect the thermal radiation of the black hole.
Fuzzy adaptive H∞ synchronization of time-varying delayed chaotic systems with unknown parameters based on LMI technique
Authors: Yang Dong-Sheng  , Zhang Hua-Guang  , Zhao Yan  , Song Chong-Hui  , Wang Ying-Chun  ,   (1)东北大学信息科学与工程学院，沈阳 110004; (2)东北大学信息科学与工程学院，沈阳 110004；东北大学教育部暨辽宁省流程工业综合自动化重点实验室,沈阳 110004; (3)沈阳工程学院自动控制工程系，沈阳 110136
Published: December 2020

The synchronization problem of two time-varying delayed chaotic systems with unknown parameters is studied. A novel fuzzy adaptive H∞ control method is proposed to realize the synchronization of two time-varying delayed chaotic systems based on Lyapunov functional theory and linear matrix inequality techniques. The sufficient criterion for the stability of the synchronization error system is presented. Finally, an illustrative example is provided to demonstrate the effectiveness of the proposed method.
Suppressing spiral waves and spatiotemporal chaos in cardiac tissue using local feedback
Authors: Zhong Min  , Tang Guo-Ning  ,   广西师范大学物理科学与技术学院，桂林 541004
Published: December 2020

Suppression of spiral waves and spatiotemporal chaos are considered based on the LuoRud91model. We apply local feedback to suppress spiral wave and spatiotemporal chaos. Two control strategies are proposed, namely the static and the moving control methods. It is found that when related parameters are properly chosen spiral wave can be suppressed by static controller, whereas spatiotemporal chaos cannot be suppressed effectively. However, spiral wave and spatiotemporal chaos can be suppressed effectively by moving controller. The corresponding control speed depends on the traveling speed of controller. Spiral wave and spatiotemporal chaos can be suppressed in a short time when the control parameters are suitably chosen.
Research on the deterministic complex network model based on the Sierpinski network
Authors: Xing Chang-Ming  , Liu Fang-Ai  ,   山东师范大学信息科学与工程学院，济南  250014
Published: December 2020

In the last few years, the complex network has received considerable attention. It is proven that the small-word effect and scale-free property exist in various real-life networks. In this paper, based on the deterministic fractal—the Sierpinski gasket, two deterministic complex network evolving models, S-DSWN and S-DSFN, are proposed by iterative approach. S-DSWN can generate small-world network, while S-DSFN can generate scale-free networks. The iterative algorithms to generate the models are also designed. Then, some relevant characteristics of the networks, such as degree distribution, clustering coefficient, and diameter, are computed or predicted analytically, which match well with the characterizations of various real-life networks. Finally, an integrated model is introduced to unify S-DSWN and S-DSFN into the same framework, which makes it convenient to study the complexity of the real networked systems within the framework of complex network theory. Moreover, we have proven that these network models are maximal planar graphs.
Infrared spectroscopic ellipsometry studies of ion-implanted and annealed silicon wafers
Authors: Liu Xian-Ming  , Li Bin-Cheng  , Gao Wei-Dong  , Han Yan-Ling  ,   (1)中国科学院光束控制重点实验室，中国科学院光电技术研究所，成都  610209; (2)中国科学院光束控制重点实验室，中国科学院光电技术研究所，成都  610209；中国科学院研究生院，北京  100049
Published: December 2020

The optical properties of the ion-implanted and annealed silicon wafer in visible spectral range are close to the single crystalline silicon due to the annealing-induced recrystallization, resulting in the unavailability of normal visible spectroscopic ellipsometry （SE） measurements. In this study, the SE measurements are performed in infrared range （2—20 μm） to characterize the implanted and annealed wafers. An optical model based on the classical Drude free-carrier absorption equation is developed, with which the impurity concentration profile, resistivity, mobility of the carriers, and the dispersion relations of the implanted layer are determined. The relationships between these parameters and the implantation dose are also analyzed. The results suggest that the infrared SE is an effective method to characterize the annealed silicon wafers. Longer wavelength should be used to distinguish lower impurity concentration.
Molecular structures and molecular spectra for plutonium oxides
Authors: Chen Jun  , Meng Da-Qiao  , Du Ji-Guang  , Jiang Gang  , Gao Tao  , Zhu Zheng-He  ,   (1)表面物理与化学国家重点实验室,绵阳  621907; (2)四川大学原子与分子物理研究所，成都  610065
Published: December 2020

Employing hybrid HF/DFT functional in conjunction with the relativistic effective core potential for Pu atoms and all-electron basis set 6-311g（d） for O atoms, the equilibrium geometrical structures of PuO, PuO2 and Pu2O3 molecules are obtained in the geometry optimization. The infrared and Raman spectra are also calculated. The bond lengths and harmonic vibration frequencies of ground states of PuO and PuO2 molecules are all in agreement with available experimental data. In geometry optimization of Pu2O3 molecule, we have tested more than twenty initial structures with different spin multiplicities （1, 3, 5, 7, 9, 11 and 13）. A C2v geometry corresponding to electronic state of 11B2 is considered as the ground state of Pu2O3 molecule. The harmonic frequency, IR intensity, Raman scatting activity and depolarization ratio of Pu2O3 molecule are obtained for the first time in theory. The vibrational modes corresponding to the maximum peaks are assigned for PuO2 and Pu2O3 molecules. In all studied molecules, the charge transfers from Pu to O atoms are found from natural bonding orbital analysis （NBO）. Relative to PuO and PuO2 molecules corresponding to Pu-O single- bond, the interactions between Pu and O in Pu2O3 are much weaker. The spin magnetic moments of studied molecules stem mainly from the 5f atomic orbitals of Pu atoms, but for O atoms the antiparallel spins from 2p atomic orbital are exhibited.
Monte-Carlo fitting and its application in electron momentum spectroscopy data processing
Authors: Zhang Zhe  , Obergfell Kyle  , Xianming L. Han  , Chen Xiang-Jun  ,   (1)Department of Physics & Astronomy,Butler University,Indianapolis,IN 46208,USA; (2)合肥微尺度物质科学国家实验室,中国科学技术大学近代物理系，合肥 230026
Published: December 2020

A new Monte-Carlo （M-C） curve fitting algorithm which is more stable than other iterative fitting algorithms is presented, and it is used to improve the unsatisfactory fitting results of the data of electron momentum spectroscopy（EMS） experiment due to the serious overlap of adjacent peaks of orbital energy resulting from the poor energy resolution. The VB program of this method has been compiled. The results of EMS data of CF2Br2 using the M-C program is compared with the one using PeakFit software, which is based on Levenberg-Marquardt algorithm, and shows much better effect. Furthermore, the ordering of the four outer valence orbitals（4b2, 2a2, 4b1 and 6a1） has been assigned, which suports the conclusion of the Hartree-Fock and OVGF calculation and revises the assignment using PES.
Experimental macroscopic phenomena in urban transportation system
Authors: He Zheng-Bing  , Ma Shou-Feng  , He Guo-Guang  ,   天津大学系统工程研究所，天津  300072
Published: December 2020

Based on the multi-agent approach and the swarm platform，a macroscopic simulation of urban transportation system is developed. In the simulation，travelers are divided into three groups first，and then links，intersections and travelers are treated as agents respectively. Three different experiments，namely traveling scales，traveler groups and network structure experiments，are carried out by the simulation. Through comparing and analyzing the simulation results from the perspectives of system scale and structure，we try to find and explain the macroscopic phenomena and the possible emergence phenomena coming from the microscopic level in urban transportation system.
Light attenuation coefficient of polarization attenuator at high attenuation level
Authors: Huang Chong  , Chen Hai-Qing  , Liao Zhao-Shu  , Zhao Shuang  ,   华中科技大学光电子科学与工程学院,武汉  430074
Published: December 2020

By use of the Jones vector we deduced the Jones matrix of actual polarizer and light transmission expression, as well as the light attenuation coefficient （LAC） of two polarizers. According to computation, certain error exists when using Malus-Law to calculate polarizer’s light attenuation ratio at high attenuation level. So the deduced LAC expression can be considered as a correction to Malus-Law. We get the maximum light attenuation ratio 2ε2 of two polarizers and light transmission expression about θ2 of three polarizers. Both the expression and experimental data indicate that the maximum light attenuation ratio can reach 2ε4 when［θ1,θ2］=［90°,135°］or［90°,315°］.
Construction of optical Hash function based on nonlinear cascaded Fourier transform
Authors: He Wen-Qi  , Peng Xiang  , Qi Yong-Kun  , Meng Xiang-Feng  , Qin Wan  , Bruce Z. Gao  ,   (1)Clemson大学生物医学工程系,501-5 Rhodes Research Center,Clemson,SC  29634,USA; (2)深圳大学光电工程学院，光电子器件与系统教育部/广东省重点实验室，深圳  518060
Published: December 2020

A method of constructing optical Hash function based on nonlinear cascaded Fourier transform is proposed. The proposed method consists of two single one-way encryption processes. In the first process, the digital information is divided to several data blocks with 512-bit each. The data blocks are encoded to 8 by 8 sub-images with 256 gray scales, creating information planes. Then take a nonlinear cascaded Fourier transform of sub-image to generate a data matrix through an optical/digital hybrid system. By extending the data matrix we get four information planes. Again, taking nonlinear cascaded Fourier transform to built information planes, we get a Hash value 64-bit long （hash1）. In the second process, we shift cydically every numerical value of the original information planes by 4-bit, constructing auxiliary information planes. Thereafter we take the same operations as we have done in the first process to the Hash value （hash2）. Once hash1 and hash2 obtained, they are combined to form a final Hash value 128-bit long （hash）. Furthermore, the avalanche effect coefficient （AEC） was also proposed to evaluate the performance of the optical Hash function. Theoretical analysis and simulation results are presented to show the effectiveness of optical Hash function constructed by our approach and the constructed optical Hash function has good performance of avalanche effect and collision resistance.
Evolution properties of the field quantum entropy in the nonlinear Jaynes-Cummings model of a trapped ion
Authors: Liu Wang-Yun  , Bi Si-Wen  , Dou Xi-Bo  ,   中国科学院西安光学精密机械研究所瞬态光学与光子技术国家重点实验室,西安 710119
Published: December 2020

The time evolution properties of the field quantum entropy in the system of a trapped ion interacting resonantly with a standing-wave laser field is studied by utilizing the Von Neumann reduced quantum entropy theory, and our attention focuses on the discussion of the influence of the Lamb-Dick parameter, the position of the ion in the standing-wave laser field and the initial state of the trapped ion on the evolution properties of the field quantum entropy. The results obtained from the numerical calculation indicate that: the value of the Lamb-Dick parameter effect the oscillation frequency and amplitude of the quantum entanglement between the trapped ion and the standing-wave laser field, the larger the Lamb-Dick parameter is, the weaker the average entanglement level between the ion and the field will be. When moving the tapped ion from the node of the standing-wave laser to the loop, the vibration frequency of the quantum entanglement between the field and the ion becomes slow gradually, and the entanglement degree gets weaker and weaker. With the decrease of the probability of the trapped ion being in the excited state, the quantum entanglement between the trapped ion and the stanging-wave laser field shows the tendency of increase first and then decrease. These properties have certain reference value for the preparation of entangled states and for the quantum communications with the thapped ion, and so on.
Quantum interference in the cavity field spectra of nondegenerate two-photon Jaynes-Cummings model
Authors: Li Yue-Ke  , Zhang Gui-Ming  , Gao Yun-Feng  ,   聊城大学传媒技术学院,聊城 252059
Published: December 2020

The cavity field spectra of two modes field both in the binomial state interacting with a two-level atom 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 shown that the quantum interference term performs periodical damped oscillation with the changing of the difference of the two field frequencies. The periodicity is about 016 g（g is the coupling coefficient between the atom and the fields）. When the difference of the two field frequencies is larger than 16 g, the quantum interference term can be ignored. Otherwise, the quantum interference term is related to photon number of initial field. The quantum interference term strengthens gradually with the photon number increasing, but weakens abruptly when the maximal photon number becomes greater than 4 The quantum interference phenomenon almost vanishes when the photon number is greater than 6.
Photon emission of single quantum dot driven by continuous external field studied by using the generating function
Authors: Peng Yong-Gang  , Zhang Xi-Zhong  , Zhang Zhao-Yu  , Zheng Yu-Jun  ,   (1)济宁职业技术学院计算机系，济宁  272000; (2)青岛农业大学建筑工程学院，青岛  266109; (3)山东大学物理学院，济南  250100
Published: December 2020

We studied the properties of the X- and Y- polarized photon emission from the single quantum dot system driven by external cw laser using the generating function approach developed recently. The results demonstrate that the X- and Y- polarized photon show sine or cosine behavior with the field direction in the weak field region. They show, however, stronger nonlinear behavior in the strong field region.