bluuebunny/crossref_metadata_2025 huggingface dataset:
Theoretical analysis of the five-mirror femtosecond Ti:sapphire oscillator containing a semiconductor saturable absorber mirror with negative Kerr effect
Authors: Wang Zhuan  , Wang Qing-Yue  , Song You-Jian  , Xing Qi-Rong  , Chai Lu  ,   天津大学精密仪器与光电子工程学院超快激光研究室，光电信息技术科学教育部重点实验室，天津  300072
Published: December 2020

The five-mirror laser cavity containing a semiconductor saturable absorber mirror (SESAM) with negative Kerr effect is theoretically analyzed for the first time. It shows that, compared with the cavity without a SESAM, the upper stable range of the resonator expands obviously after the introduction of SESAM. This indicates that the work point for self-starting can be more close to the edge of the stable range of the CW state, and then get higher nonlinear effect. This shows that the negative Kerr effect of the SESAM can contribute to the self-starting of the modelocked laser besides the saturable absorption mechanism.
Multiscale modeling of single vacancy state
Authors: Zheng Li-Bao  , Wang Chong-Yu  ,   (1)清华大学物理系,北京  100084; (2)清华大学物理系,北京  100084;中国科学院国际材料物理中心,沈阳  110016
Published: December 2020

Based on multiscale concurrent algorithm, we have implemented a unified dynamics scheme and investigated displacement distribution, oscillation behavior, energy fluctuation, charge density difference and the effect of environment of single vacancy system. The displacement distribution and the related behavior reflect the quantum effect of single vacancy. At the same time, the calculations of the total energy and charge density difference revealed the effect of environment and indicated the coupling between the classical and quantum effects.
A study on the mechanism of the influence of Bi, Sb alloying on microstructure and properties of AZ91 magnesium alloy
Authors: Zhang Guo-Ying  , Zhang Hui  , Fang Ge-Liang  , Li Yu-Cai  ,   沈阳师范大学物理科学与技术学院,沈阳  110034
Published: December 2020

The atomic structure model of symmetric ［0001］tilt boundary of α phase in AZ91 magnesium alloy was set up by using the concept of coincidence-site lattice (CSL). The total structure energies of α matrix and grain boundary (GB), the environment sensitive embedding energies (EESE) and the interaction energies of Al, Bi and Sb were calculated by using recursion method. The alloying behaviour of Al, Bi, Sb in AZ91 magnesium alloy was discussed. Calculation results show that the total structure energies of α matrix and grain boundary (GB) are decreased due to the presence of Al, Bi or Sb, which suggests AZ91 alloy is strengthened due to solid solution strengthening. Alloying elements tend to be distributed uniformly in α matrix, and are apt to occupy the top sites of the trigonal prism formed by Mg in the GB core. The aggregation of Bi or Sb to GBs,being easier than Al, suppresses the aggregation of Al, which accelerates the formation of continuous precipitates, improves the high temperature properties. The major alloying element Al and the additional elements Bi or Sb in small amounts can form the ordered phases in AZ91 alloys: Mg１７Al１２, Mg3Bi2 and Mg３Sb２, respectively, and the quantity of the ordered phase is greater in GBs than in α(Mg) matrix. Bi or Sb additions to AZ91 retards the aggregation of Al, and Mg3Bi2 or Mg３Sb２ precipitates along boundaries greatly improve the high temperature properties.
Spectroscopic characteristics of Cr3+:Al2O3 polycrystalline transparent alumina ceramics
Authors: Zeng Zhi-Jiang  , Yang Qiu-Hong  , Xu Jun  ,   (1)上海大学材料科学与工程学院，上海  200072; (2)中国科学院上海光学精密机械研究所，上海  201800
Published: December 2020

Spectral properties of transparent polycrystalline Cr3+:Al2O3 ceramics were studied. The results indicated that the absorption peaks of polycrystalline Cr3+:Al2O3 ceramics co incide with the absorption spectrum of a ruby single crystal. The crystal field and Racah parameters were calculated according to the Tanabe-Sugano energy level diagram and absorption spectra. The crystal field intensity of Cr3+: Al2O3 polycrystalline ceramics is almost the same as that of Cr3+:Al2O3 single crystal, and the character istics of the emission spectra still retains the R-line emission even as the Cr3+ concentration increases up to 0.8wt%. In particular, one 670nm emis sion peak of Cr3+ was first found in the polycrystalline ceramics.
Fluorescence spectrum characteristics of ethanol-water clusters
Authors: Liu Ying  , Peng Chang-De  , Lan Xiu-Feng  , Luo Xiao-Sen  , Shen Zhong-Hua  , Lu Jian  , Ni Xiao-Wu  ,   (1)南京理工大学理学院，江苏南京  210094; (2)南京理工大学理学院，江苏南京  210094;徐州师范大学物理系，江苏徐州  221009; (3)徐州师范大学物理系，江苏徐州  221009
Published: December 2020

The fluorescence spectra of the ethanol-water mixture excited by ultraviolet lig ht and the excitation spectra corresponding to the fluorescence peaks are inves tigated respectively. It is found that the mixtures emit fluorescence photons, which is different from pure ethanol and water. One can conclude that new molec ule clusters are created by mixing of the ethanol and water molecules. The inci dent light of different wavelengths irradiates the solution and the fluorescen ce quantum yield at each wavelength is calculated firstly, and then the excited light with the maximum quantum yield is selected to irradiate the mixture. By the experimental results of fluorescence spectra of solution with different con centrations, the possible structures of these new molecule clusters are discuss ed. The general absorptivity and fluorescence counts are calculated basing on t he additive property of absorptivity and fluorescence intensity, elucidating the fluorescence spectra characteristic of ethanol-water mixture. The research may contribute to the study of the new molecule clusters of ethanol-water.
Abrupt climate change detection based on heuristic segmentation algorithm
Authors: Feng Guo-Ling  , Gong Zhi-Qiang  , Dong Wen-Jie  , Li Jian-Ping  ,   (1)扬州大学物理科学与技术学院，扬州  225009;国家气候中心气候研究开放实验室，北京  100081; (2)扬州大学物理科学与技术学院，扬州  225009;中国科学院大气物理研究所东亚区域气候-环境重点实验室，北京  100029; (3)中国科学院大气物理研究所东亚区域气候-环境重点实验室，北京  100029
Published: December 2020

Climate system is nonlinear,non-stationary and hierarchical,which makes even harder to detect and analyze abrupt climate changes.Based on Student's t-test,Berna ola Galvan recently proposed a heuristic segmentation algorithm to segment the t ime series into several subsets with different scales,which is more effective in detecting the abrupt changes of nonlinear time series.In this paper,we try to v erify the effectiveness of heuristic segmentation algorithm in dealing with nonl inear time series by an ideal time series.Through detecting and analyzing the in formation of abrupt climate changes contained in recent 2000a's tree annual grow th ring,we succeeded in distinguishing abrupt changes with different scales.The research based on the newly defined paramcter of abrupt change density shows tha t human activities might have lead to the recent 1000a's unbalanced distribution of serial and spares segments of abrupt climate changes,which may be one of the manifestations of global temperature change.
Stochastic stability and control of coupled Duffing-van der Pol systems
Authors: Li Wei  , Xu Wei  , Zhao Jun-Feng  , Jin Yan-Fei  ,   西北工业大学应用数学系，西安  710072
Published: December 2020

By using the stochastic averaging method of quasi-Hamilton system and stochastic stbilization strategy, the stochastic stability and stabilization control of a coupled Duffing-van der Pol system under Gaussian white noise excitation with in semi-infinite time interval are investigated. The results show that, with suitable controlled parameters, effective stochastic stabilization can be realized.
Perturbation theory of soliton solution for the generalized Landau-Ginzburg-Higgs equation
Authors: Mo Jia-Qi  , Wang Hui  , Lin Yi-Hua  ,   (1)安徽师范大学数学系，芜湖  241000;湖州师范学院数学系，湖州  313000; (2)中国科学院大气物理研究所，北京  100029; (3)中国气象科学研究院，北京  100081
Published: December 2020

Using the perturbed method, a class of generalized Landau-Ginzburg-Higgs equation is studied. Introducing a homotopic mapping, the solution of original equation is expressed as an asymptotic expansion, then it is expressed approximately by corresponding solutions of linear equations. Finally, the solution of equation in relation to the obtained approximate solution is considered.
Spin-orbit ab initio study of the S2(B3Σ-u→X3Σ-g(ν′≥18,0)) diffuse bands
Authors: Yan Bing  , Pan Shou-Fu  , Wang Zhi-Gang  , Yu Jun-Hua  ,   (1)哈尔滨工业大学可调谐激光技术国家重点实验室，哈尔滨  150001; (2)吉林大学原子与分子物理研究所，长春  130012
Published: December 2020

The diffuse bands B３Σ-u→X３Σ-g(ν′≥18,0) of diatomic molecule S2 observed in the experiment are investigated. The electronic potential curves,including the spin-orbit coupling (SOC) effect of B３Σ-u and repulsive 1５Πu， 23Σ+u states are calculated. For the diffuse bands beginning at (18,0), a point of view different from others' results is presented in this work. Our results indicate that the SOC induced predissociation between B３Σ-u and 1５Πu， 23Σ+u plays the key role in the diffusion of spectra. Comparison with experimental results shows good agreement.
Surface analysis of LiBq4/ITO and LiBq4/CuPc/ITO using atomic force microscopy and x-ray photoelectron spectroscopy
Authors: Ou Gu-Ping  , Song Zhen  , Gui Wen-Ming  , Zhang Fu-Jia  ,   (1)北京机械工业学院基础部，北京  100085; (2)兰州大学物理系，兰州  730000
Published: December 2020

We have investigated the surfaces of the samples LiBq4/ITO and LiBq4/CuPc/ITO. The atomic force microscopy (AFM) observations indicate that different surface morphologies are formed on different substrates, and what is more, x-ray photoelectron spectroscopy is also utilized to further demonstrate the AFM results. It is concluded that the introduction of a CuPc buffer layer under the LiBq4 layer can improve the film quality of LiBq4, and the improvement should be attributed to the differences in molecular structure and electron affinity.
Fabrication of CNx nanotubes films using different nitrogen sources and their low field emission properties
Authors: Ding Pei  , Chao Ming-Ju  , Liang Er-Jun  , Guo Xin-Yong  ,   (1)河南大学特种功能材料实验室,开封  475001; (2)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; (3)郑州航空工业管理学院应用科学系，郑州  450015;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

The CNx nanotube films have been fabricated on Si substrates by thermal decomposition when NH4Cl and C2H8N2 were used as nitrogen sources. The scanning electron microscopy, transmission electron microscopy and Raman spectroscopy were used to characterize the CNx nanotubes. It is found that not only the degrees of purity and ordering, but also the morphology of the CNx nanotubes are quite different when different nitrogen sources are used. The CNx nanotubes fabricated by pyrolyzing C2H8N2/C10H10Fe have “bamboo-like” structure and lower crystallinity,and grow horizontally in good order on silicon substrates. Low field emission measurement gives a turn-on field of 1.0V/μm and 860μA/cm2 current density at 2.89V/μm.
Noether form invariance of nonholonomic controllable mechanical systems of non-Chetaev’s type
Authors: Xia Li-Li  , Li Yuan-Cheng  , Wang Jing  , Hou Qi-Bao  ,   中国石油大学(华东)物理科学与技术学院，东营  257061
Published: December 2020

Based on the total time derivative along the trajectory of the system, the definition and the criterion of Noether form invariance of nonholonomic controllable mechanical systems of non-Chetaev’s type are presented. A new conserved quantity, as well as the Noether conserved quantity are deduced from the Noether-form invariance. An example is given to illustrate the application of the result.
Analytic tunneling-current model of small-scale MOSFETs
Authors: Chen Wei-Bing  , Xu Jing-Ping  , Zou Xiao  , Li Yan-Ping  , Xu Sheng-Guo  , Hu Zhi-Fu  ,   华中科技大学电子科学与技术系，武汉  430074
Published: December 2020

An analytic model of direct tunneling current of small-scale MOSFETs in depletion and inversion is developed based on analytic surface-potential model and replacing the multi-subband with a single-subband. The simulated results are in good agreement with the results of self-consistent solution and experimental data, but take much shorter computing time than the self-consistent solution method. This indicates that the model can be used for analysis of gate-leakage properties of MOS devices with not only SiO2 but also high-k materials as gate dielectric and high-k gate dielectric stack structures, and circuit simulation of MOS devices.
Adaptive control and synchronization of a coupled dynamos system
Authors: Wang Xing-Yuan  , Wu Xiang-Jun  ,   大连理工大学电子与信息工程学院，大连  116024
Published: December 2020

This paper addresses the adaptive control and synchronization of the coupled dynamos system with unknown system parameters. Adaptive controller is developed to suppress chaos to equilibrium points and realige synchronization of two identical coupled dynamos systems with unknown system parameters. Numerical simulations are employed to show the effectiveness of the proposed method.
Comparison between two geometrical arrangements for diffraction enhanced imaging
Authors: Huang Wan-Xia  , Zhu Pei-Ping  , Yuan Qing-Xi  , Wang Jun-Yue  , Shu Hang  , Hu Tian-Dou  , Wu Zi-Yu  ,   中国科学院高能物理研究所，北京  100049
Published: December 2020

Diffraction enhanced imaging (DEI) with two crystals has been recently performed at the 4W1A beamline at the Beijing Synchrotron Radiation Facility (BSRF). In the first experiments, images collected with a set up where the rotation axis of the crystal was perpendieular to the orbit, show a higher quality with respect to those taken with a geometry with the rotation axis of the monochromatic crystal parallel to the orbit. When the rotation axis of the crystal is perpendicular to the orbit plane, e.g. to the polarization plane of the synchrotron radiation, the influence of both vibration and thermal expansion of the first crystal can be significantly reduced, allowing the collection of better images. In this work, a systematic comparison is male between two geometrical arrangements of crystals in DEI framework with respect to the reflectivity of crystals, spacial resolution, angular resolution and image contrast.
Kinetic Monte Carlo simulation of the epitaxial growth mechanism on the vicinal surface
Authors: Mao Hui-Bing  , Jing Wei-Ping  , Yu Jian-Guo  , Wang Ji-Qing  , Wang Li  , Dai Ning  ,   (1)华东师范大学信息科学技术学院,上海  200062; (2)华东师范大学信息科学技术学院,上海  200062;中国科学院红外物理国家实验室,上海  200083; (3)南通大学江苏省专用集成电路设计重点实验室,江苏南通  226007; (4)中国科学院红外物理国家实验室,上海  200083
Published: December 2020

In this paper the epitaxial growth mechanism on vicinal GaAs(001) surface is studied using the kinetic Monte Carlo simulation method. The Ehrlich-Schwoebel barrier has great influence on the growth mechanism of the vicinal surface. The simulation results show that the downward movement to a lower step of the adatoms can be inhibited by Ehrlich-Schwoebel barrier at low temperature, while the adatoms can move to the lower step at high temperature. At the beginning of growth, the adatoms are almost distributed uniformly on the steps. When the surface coverage reaches to certain value, the step nucleation begins. Meanwhile, the adatoms begin to accumulate at the upper step because of the Ehrlich-Schwoebel barrier. If there were no Ehrlich-Schwoebel barrier, the adatoms at the upper step could be depleted completely. The Ehrlich-Schwoebel barrier has great influence on the growth mode of the vicinal surface, and it will increase the temperature for onset of the step growth mode.
Study on the energy transfer and luminescent properties in PVK:DBVP blend system
Authors: Zhang Peng  , Zhou Yin-Hua  , Liu Xiu-Fen  , Tian Wen-Jing  , Li Min  , Zhang Guo  ,   (1)吉林大学 材料科学与工程学院,长春  130012; (2)吉林大学 超分子结构与材料教育部重点实验室,长春  130012; (3)吉林大学 超分子结构与材料教育部重点实验室,长春  130012;吉林大学 材料科学与工程学院,长春  130012
Published: December 2020

The energy transfer and the luminescence properties of polyvinyl-carbazole (PVK) and oligomeric phenylenevinylene derivative (2,5-dodecyloxy-1,4-(biphenyl-enevinyl )phenyl)(DBVP)blend system were studied. The energy transfer between PVK and DBVP was investigated by the UV-vis absorption spectra, photoluminescent excitation (PLE) spectra and photoluminescent (PL) spectra of PVK/DBVP blend system. The electroluminescence (EL) properties of the blend system were investigated by characterization with the device ITO/PEDOT/PVK∶DBVP (w/w)/LiF/Al. The PL and EL spectra of PVK in the PVK/DBVP system were effectively quenched, which means the effective energy transfer between PVK and DBVP. Because PVK matrix acted as solid solvent, the emission performance of the blend system could be adjusted and improved by changing the ratio of PVK and DBVP. The luminescence efficiency is up to 1.06cd/A at 52cd/m2, when the weight ratio of PVK∶DBVP was 1:2 and the bright blue and green light emission were obtained when the ratio of PVK∶DBVP was changed from 20∶2 to 1∶2.
Study on the magnetic entropy change and magnetic phase transition of NaZn13-type LaFe13－xAlxCy compounds
Authors: Zhang Li-Gang  , Chen Jing  , Zhu Bo-Quan  , Li Ya-Wei  , Wang Ru-Wu  , Li Yun-Bao  , Zhang Guo-Hong  , Li Yu  ,   (1)湖北省耐火材料与高温陶瓷重点实验室-省部共建国家重点实验室培育基地，武汉  430081; (2)武汉科技大学应用物理系，武汉  430081
Published: December 2020

The refrigerant capacity and magnetic phase transition of NaZn13-type LaFe13-xAlxC0.1(x=1.6，1.8) interstitial compounds are investigated. The magnetic entropy change |ΔS|m, which is calculated from one of the Maxwell’s relationships ΔS(T,H)=-∫( M/T)HdH, is lower than that of carbides with low Al content. Although the magnetic entropy change peak broadens with increasing Al content, the value of q, which is used to evaluate the refrigerant capacity, decreases due to the sharp derease of the magnetic entropy change. Taking the spin fluctuation into account, the magnetic free energy can be expanded up to the M6 term based on the Landau phase transition theory. The order of phase transition is distinguished by the the signs of a3(T), which is the coefficient of M4 term. The order of phase transition for LaFe13-xAlx carbides changes from the first one that is weak to the second one with the increase of Al content.
One-way Hash function based on chaotic neural network
Authors: Liu Guang-Jie  , Shan Liang  , Dai Yue-Wei  , Sun Jin-Sheng  , Wang Zhi-Quan  ,   南京理工大学自动化学院，南京  210094
Published: December 2020

In this paper, a new one-way Hash function is proposed based on chaotic neural network. With the neural network with piecewise linear chaotic map as the output function, the key generation function based on spatiotemporal chaotic system are used to realized the data confusion and diffusion. By the cipher block chaining mode, the proposed method can produce 128-bit Hash value for plaintext with arbitrary length. Theoretical analysis and experimental results indicate that the proposed Hash function satisfies the demands in performance, such as being one-way, having initial value and key sensitivity, collision resistance and real-time applicability.
One-way Hash function construction based on tangent-delay ellipse reflecting cavity-map system
Authors: Sheng Li-Yuan  , Li Geng-Qiang  , Li Zhi-Wei  ,   中南大学物理科学与计算技术学院,长沙  410083
Published: December 2020

An algorithm for one-way Hash function construction based on tangent-delay ellipse reflecting cavity-map system (TD-ERCS) is proposed in this paper. In the algorithm, the plaintext dealt with is first transformed into a systemic parameter sequence linearly, and then TD-ERCS is iterated in order of the parameter sequence directly, the final Hash value of 160 bits is obtained by means of the nonlinear transform on the iteration sequence, and no padding of calculation is added. Users’ keys of the algorithm can be chosen in the region［264, 2160］ arbitrarily. Theoretical analysis and basic security tests indicate that our Hash function has good one-way, weak collision property, better security than other chaotic Hash functions, and it can be realized easily with great rapidity. Our algorithm of Hash function is an ideal substitution for conventional Hash function. And also, a natural criterion (theoretical value of 85.33) to evaluate collision property of Hash function is educed in this paper.
Monte Carlo simulation of electron transmission through masks in projection electron lithography
Authors: Xiao Pei  , Zhang Zeng-Ming  , Sun Xia  , Ding Ze-Jun  ,   (1)合肥微尺度物质科学国家实验室，中国科学技术大学天文与应用物理系,合肥 230026; (2)合肥微尺度物质科学国家实验室，中国科学技术大学物理系,合肥  230026
Published: December 2020

We have calculated electron energy loss spectrum for electrons transmitted through a mask in projection electron lithography by Monte Carlo simulation based on the dielectric function model and Mott elastic scattering cross section. A good agreement between simulation and experiment is obtained. The calculation results of the transmission and contrast for the masks in scattering angular limitation for projection electron lithography show that the contrast is dominated by the thickness of scattering layer (thicker the scattering layer higher the contrast), but is less affected by the thickness of the supporting membrane. Furthermore, with the increasing aperture angle the transmission increases but the contrast reduces, and the contrast decreases with increasing primary energy of electrons.
Analytical thermal model and characterization of lateral thermal effects in AlInGaAs vertical-cavity top-emitting lasers
Authors: Wu Jian  ,   北京航空航天大学理学院物理系，北京  100083
Published: December 2020

An optimized comprehensively analytical thermal model was developed in accordance with interior heating characteristics of a gain-guided, top-emitting vertical-cavity surface-emitting laser with c.w. operation under room temperatures. Lateral thermal effects in AlInGaAs/AlGaAs vertical-cavity surface-emitting lasers were calculated analytically in detail. The comprehensively analytical solutions exhibited a clearer physical picture of the lateral heat-flux diffusion. The theoretical predicts of the interior thermal variation within the device were consistent with the experimental results as well. The work provides a useful tool for investigation of thermodynamic properties of the vertical-cavity surface-emitting lasers under thermal steady state, optimization of the device structure and control of the threshold current and power saturation effect, especially for the lateral thermal crosstalk in 2-dimensional arrays.
The PIC/MCC simulation of the ionization processes in electron cyclotron resonance discharge (Ⅰ)——Physical model and theoretical methods
Authors: Jin Xiao-Lin  , Yang Zhong-Hai  ,   电子科技大学物理电子学院，成都  610054
Published: December 2020

We present a theoretical and computational model to study the ionization of the electron cyclotron resonance (ECR) microwave discharge using a quasi-three-dimensional electromagnetic particle-in-cell plus Monte Carlo collision method. The interaction between the charged particles and microwave fields are described by particle-in-cell method. The collision processes are treated with Monte Carlo method. Elastic, excitational, and ionizing electron-neutral collisions and elastic, charge exchange ion-neutral collisions are included. The cross sections are the functions of particle’s energy. The theoretical part of simulation is introduced in detaid as foundation of the numerical simulation.
Biological response of Arabidopsis seed to MeV proton irradiation at different region of its embryo
Authors: Qin Huai-Li  , Xue Jian-Ming  , Lai Jiang-Nan  , Wang Jian-Yong  , Miao Qi  , Zhang Wei-Ming  , Ma Lei  , Yan Sha  , Zhao Wei-Jiang  , Gu Hong-Ya  , Wang Yu-Gang  ,   (1)北京大学生命科学学院，北京  100871; (2)北京大学重离子物理教育部重点实验室,北京  100871
Published: December 2020

The water saturated Arabidopsis seeds were irradiated with protons in air. The ion energy is from 1.1MeV to 6.5MeV. According to TRIM simulation, the damaged region of the seed induced by the incident ions is near the surface region of the embryo, half of the embryo and the whole embryo, respectively. The protons with high energy can damage the shoot apical meristem(SAM) in the embryo while the protons with low energy cannot. The ion fluence used in this experiment was in the range of 4×109 to 1×1014ions/cm2. The experimental results showed that both the germination and survival rates decrease while increasing ion fluence, and the fluence-response curve for different damaged region of the embryo has different characters. Besides SAM, which is generally considered as the main radiobiological target, the existence of a secondary target besides SAM is proposed in this paper.
Field-emission properties of aligned and unaligned In2O3 nanowires
Authors: Hu Li-Qin  , Lin Zhi-Xian  , Guo Tai-Liang  , Yao Liang  , Wang Jing-Jing  , Yang Chun-Jian  , Zhang Yong-Ai  , Zheng Ke-Lu  ,   福州大学电子科学与应用物理系，福建  350002
Published: December 2020

Aligned and unaligned In2O3 nanowires were prepared based on our homemade equipment and the field-emission properties of In2O3 nanowires(NWs) were investigated.It was found that aligned In2O3 NWs have better performance than unaligned ones. The aligned NWs have lower turn-on and threshold electric fields. This might be attributed to the weaker field-screening effect between the neighboring aligned NWs, and the existence of more exposed tips as emitters in the aligned NWs.
Eu3+ luminescence in neoceramic glass as ion microprobe
Authors: Yu Hua  , Sun Jian  , Liu Bao-Rong  , Song Jie  , Zhao Li-Juan  , Xu Jing-Jun  ,   (1)南开大学物理科学学院光子学中心,天津  300071; (2)南开大学物理科学学院光子学中心,天津  300071；弱光非线性光子学材料先进技术及制备教育部重点实验室，天津市信息光子材料与技术重点实验室，南开大学泰达应用物理学院，天津  300457
Published: December 2020

In oxyfluoride glass-ceramics, the fluoride nanocrystals doped with rare earth ions were dispersed in an oxide network. The emission of Eu3+ has high sensitivity to different crystal field and is suitable for microstructure research in neoceramic glass. Different oxyfluoride glass ceramics doped with Eu3+ were prepared. The variation of the emission spectra of Eu3+ in different glass ceramics confirms the applicability of Eu3+ ions in neoceramic glass as microprobe before and after heat treatment.
Synchrotron radiation stimulated etching of SiO2 thin films
Authors: Wang Chang-Shun  , Pan Xu  , Urisu Tsuneo  ,   (1)Institute for Molecular Science,Okazaki,444-8585,Japan; (2)上海交通大学物理系，上海  200240
Published: December 2020

The synchrotron radiation (SR) stimulated etching of SiO2 thin film surface was investigated with a contact cobalt mask, and the etched pattern of SiO2 thin films on silicon was made. The SiO2 thin film was grown on silicon surface by thermal oxidation. The contact cobalt mask was fabricated on SiO2 thin film by combining the techniques of photolithography and RF-magnetron sputtering. In the experiment, the anisotropic etching of SiO2 was effectively achieved by SR radiation with SF6 as the reaction gas. The etching rate increased with increasing gas pressure of SF6 in a certain range, and with decreasing the substrate temperature. Under SR irradiation with flowing SF6 and O2 did not etch the silicon crystal and the etching stopped completely at the SiO2/Si interface. Furthermore, the Co provided high resistance against the SR etching, indicating that Co is an ideal mask material for the synchrotron radiation stimulated etching.
Teleportation of entangled coherent state through bipartite entangled quantum channels
Authors: Liu Chuan-Long  , Zheng Yi-Zhuang  ,   温州大学物理与电子信息学院，温州  325027
Published: December 2020

We propose a scheme for teleportation of an entangled coherent state through bipartite entangled quantum channels. We study the problem in both coherent state picture and orthogonal basis picture composed of coherent states, and find that in the coherent state picture teleportation can be implemented using only linear elements, but the probability of success is less than 1/2, while in the orthogonal basis picture the probability of successful teleportation reaches 1 as long as the four Bell states can be discriminated.
Stochastic resonance of amplitude modulated wave in a linear model of single-mode laser
Authors: Zhang Liang-Ying  , Cao Li  , Jin Guo-Xiang  ,   (1)华中科技大学激光技术国家重点实验室,武汉  430074; (2)武汉工程大学计算机学院，武汉  430073; (3)襄樊学院物理系，襄樊  441053
Published: December 2020

By adding modulated wave to the equation of the laser intensity of the gain-noise model of the single-mode lasers, we use the linear approximation method to calculate the power spectrum and signal-to-noise ratio(SNR) of the laser intensity, which is driven by two white noises correlated in the form of δ function. The result show that the SNR shows stochastic resonance with the varing of not only intensities of the pump noise and quantum noise，but also the frequency of a high frequency carrier signal and frequency of a low frequency periodical signal.
Stochastic chaos in stochastic Duffing systems and its control by delayed feedback
Authors: Wu Cun-Li  , Ma Shao-Juan  , Sun Zhong-Kui  , Fang Tong  ,   (1)西北工业大学理学院，西安  710072; (2)西北工业大学力学与土木建筑学院，西安  710072; (3)西北工业大学力学与土木建筑学院，西安  710072;中国飞机强度研究所，西安  710065
Published: December 2020

The problem of stochastic chaos and its control by delayed feedback in a Duffing system with bounded random parameters (a stochastic Duffing system in short) under harmonic excitations is considered in detail. At first, the stochastic Duffing system is transformed into its equivalent deterministic nonlinear system by the Gegenbauer polynomial approximation. Thus, the problem of chaotic response and its control in stochastic Duffing system can be reduced to that in an equivalent deterministic system. So the available effective mathematical methods and control strategies can be applied to the latter. Then, the main feature of stochastic chaos is fully explored, where the top Lyapunov exponent of the equivalent system obtained by Wolf's algorithm is used to identify the dynamic behavior of stochastic Duffing system. Finally, the control strategy of delayed feedback is applied to suppress or to induce chaotic response in the system. The results of numerical simulation show that by proper choice of feedback intensity and time delay, either suppressing or inducing stochastic chaos can be achieved. Hence, the strategy of delayed feedback control is also effective to stochastic chaos.
Propagation of electromagnetic wave in a lossy cylindrical waveguide
Authors: Jiao Chong-Qing  , Luo Ji-Run  ,   (1)中国科学院电子学研究所,北京 100080; (2)中国科学院电子学研究所,北京 100080;中国科学院研究生院,北京 100049
Published: December 2020

Based on the dispersion equation of electromagnetic mode, the propagation characteristics in a lossy cylindrical waveguide are studied. The analytic formula of propagation constant for all modes in the waveguide is presented, which includes the effects of the thickness of the lossy layer. A large uumber of numerical calculations using the analytic formula and the dispersion equation have been carried out on the relations of the attenuation and phase constant with wave frequency, thickness and conductivity of the lossy layer. The analytic calculation results are in good agreement with those of the dispersion equation. This research is useful for selecting appropriate distributed wall losses for the stable and wide-band operation of gyrotron traveling wave amplifiers.
Numerical analysis of the scaling laws about focused beam spreading induced by the atmosphere
Authors: Huang Yin-Bo  , Wang Ying-Jian  ,   中国科学院安徽光学精密机械研究所，合肥  230031
Published: December 2020

Using typical sets of numerical parameters under characteristic laser beam propagation conditions, focused beam spreading induced by atmospheric turbulence and thermal blooming is analyzed by numerical simulation. In the analysis of the combined effect, we assume that the thermal blooming effect arises in consequence of the increase in beam radius induced by atmospheric turbulence and beam jitter. The scaling relations between the laser propagation effects and characteristic parameters describing the propagation in atmosphere are obtained. Based upon these relations, we can efficiently estimate atmospheric propagation effects and learn the performance of a particular system design under various environmental conditions, as well as conduct laser system design optimization.
Interaction of two kind scales in Lorenz equation
Authors: Liu Feng  , Liu Shi-Da  , Liu Gang  , Liu Shi-Kuo  ,   (1)北京大学物理学院大气科学系，北京 100871; (2)北京大学物理学院大气科学系，北京 100871;民航南昌空中交通管理中心，南昌 330114; (3)北京大学物理学院大气科学系，北京 100871;民航中南空中交通管理局气象中心，广州 510406
Published: December 2020

In the chaos range of Lorenz equation, there is interaction between the smaller and larger scales. On the one hand, the Rayleigh number r determines the convective and turbulent flows in the air. On the other hand, the convective and turbulent flows have a feedback to the larger scale condition. The result of interaction between the scales leads to the decrease of the value of r, until the steady state of Lorenz equations is established. During the feedback process, the variation in vertical thermal flux xy and vertical temperature gradient z are the main causes that decide the change of number r. Moreover the end result of feedback displays a abrupt change.
Stochastic chaos and its control in the stochastic Bonhoeffer-Van der Pol system
Authors: Zhang Ying  , Xu Wei  , Sun Xiao-Juan  , Fang Tong  ,   (1)北京航空航天大学理学院,北京 100083; (2)西北工业大学理学院应用数学系,西安 710072; (3)西北工业大学力学与土木建筑学院,西安 710072
Published: December 2020

In this paper, the stochastic chaos of the stochastic Bonhoeffer-Van der Pol system with bounded random parameter and its control by noise are investigated. The stochastic Bonhoeffer-Van der Pol system is first transformed into an equivalent deterministic system using the Chebyshev polynomial approximation, so that the problem of controlling stochastic chaos is reduced to the problem of controlling deterministic chaos in the equivalent system. Thus, the top Lyapunov exponent of the equivalent system can be used to examine the chaotic behavior and its control of the responses. The numerical simulations show that the chaos behavior in the stochastic Bonhoeffer-Van der Pol system is by and large similar to that in the equivalent deterministic Bonhoeffer-Van der Pol system. The chaos behavior can be controlled to the periodic states by noise, but under the effect of the random parameter and its intensity, it has cortain specific features.
A comparative study of propagation properties of Hermite-Gaussian beams through gratings with sinusoidal and rectangular reliefs
Authors: Li Jian-Long  , Lü Bai-Da  ,   四川大学激光物理与化学研究所，成都 610064
Published: December 2020

By using the rigorous Fourier's modal theory and recursion algorithm of the reflection-transmission coefficient matrix(RTCM), the propagation of Hermite-Gaussian beams of different orders through gratings with sinusiodal and rectangular reliefs whose characteristic size is comparable with the wavelength, are studied and compared in detail. It is shown that the field distribution of incident beam and the structure of grating relief affect intensity distributions within the gratings. Better beam smoothing is achieved by using the rectangular-reliefed grating than using the sinusoidal-reliefed grating.
Controlling the optical limiting shape in stimulated Brillouin scattering by dye absorption
Authors: Lü Yue-Lan  , Lü Zhi-Wei  , Dong Yong-Kang  ,   (1)哈尔滨工程大学理学院，哈尔滨 150001; (2)哈尔滨工业大学光电子技术研究所，哈尔滨 150001
Published: December 2020

On the basis of computing models of stimulated Brillouin scattering (SBS), the optical limiting response characteristics in SBS process are investigated theorctieally. Dependence of limiting parameter ——residual energy on pump parameters (input power density, pulse duration), medium parameters (gain, phonon life time) and configuration parameters (focusing length, cell length) are analyzed. Response characteristics of SBS limiting are given by studying the variation of delay time, residual peak power and residual energy. Ideal response system can be obtained by choosing a medium with larger gain and shorter phonon life time. But the vesidual energy could not be got rid of by choosing SBS medium parameters only. In experiment, we obtained flat-roofed optical limiting pulse shapes in SBS process using dye absorption.
Optical parameters and energy level splitting of Er3+ in Er3+: GdVO4
Authors: Wang Ce  , Chen Xiao-Bo  , Zhang Chun-Lin  , Zhang Yun-Zhi  , Chen Luan  , Ma Hui  , Li Song  , Gao Ai-Hua  ,   (1)北京师范大学物理系，应用光学北京重点实验室，分析测试中心，北京 100875; (2)中国科学院物理研究所，北京 100080
Published: December 2020

Er3+: GdVO4 is a new laser material which is suitable for high-power laser systems. In this paper we firstly measured the absorption spectrums of Er3+ in the sample Er3+: GdVO4, then the intensity parameters were calculated using Judd-Ofelt theory. After that we calculated some predicted spectroscopic parameters, such as the spontaneous radiative transition rate, branching ratio and integrated emission cross section, which were then compared with the data of other common materials. It was found that there are many transitions with large oscillator strength and large integrated emission cross section, especially 2H11/2→4I15/2, 4S3/2→4I15/2, 4F9/2→4I15/2 and 4I13/2→4I15/2, which are useful in solid-state laser and communications fields. Finally, we discuss the splitting of the energy levels of Er3+ in the crystal GdVO4 through the group theory, and also analyze the intermix of Jz in Starks levels.
Chaos prediction in the Duffing-type system with non-smooth periodic perturbation and bounded parametric excitation
Authors: Niu Yu-Jun  , Xu Wei  , Rong Hai-Wu  , Wang Liang  , Feng Jin-Qian
Published: December 2020

In this paper, the dynamics of Duffing-type system with non-smooth periodic perturbation and bounded noise was studied. The theory of Fourier series was used in this system to deal with the non-smooth character for the first time. The analytical condition for the appearance of chaos was given using stochastic Melnikov method. The numerical simulations confirm the validity of this method.
Phase diagram of diblock copolymer confined in a cylindrical nanopore with polymer-grafted surface
Authors: Li Ming  , Zhu Yue-Jin
Published: December 2020

Using self-consistent field calculation, the new equilibrium morphology of a diblock copolymer melt confined in a brush_covered cylindrical nanopore can be found. The morphology is formed as a function of brush density and A-monomer fraction f. When f=0.7, due to the wetting effect produced by polymer brush the outside concentric lamellar ring will come up again with increasing φAB. We carefully examined the intermediate phases and discovered a rich variety of new two_dimensional structures that have no analogue in the unconfined system, which include nonhexagonally coordinated cylinder phases and structures intermediate between lamellae and cylinders, like CRCR, when f=0.35. Then we map the stability regions and phase boundaries for all the structures we found.
Transformation properties of gauge invariance systems at the quantum level and an application
Authors: Li Ai-Min  , Li Zi-Ping
Published: December 2020

According to Faddeev-Popov's rule of path integral quantization, the generating functional of Green function in configuration space for a gauge_invariant constrained system is formulated, transformation properties of a gauge_invariant system at the quantum level are derived and the problems of the conserved laws at the quantum level are discussed. the quantal transformation properties of electromagnetic field near the interface of dielectric media under the Poincar group are studied. It is pointed out that the transverse shift of the reflection and refraction of electromagnetic waves near the interface of dielectric media also occur at the quantum level, but the results of classical theory must be amended in quantum theory.
Generation of an adjustable double-well optical trap by shift phase gratings
Authors: Ji Xian-Ming  , Xu Shu-Wu  , Lu Jun-Fa  , Xu Dong-Mei  , Yin Jian-Ping
Published: December 2020

A novel scheme was proposed to form the double-well optical trap by using shift phase gratings. A few pairs of adjustable double-well optical traps for trapping cold atoms or cold molecules were formed on the focal plane when the gratings were illuminated by plane light wave (or TEM00 mode Gaussian light wave) and focused by positive lens. The intensity distribution was calculated, and then the intensity distribution gradients as well as the analytical relations between geometrical parameters of the traps and the parameters of the optical system were derived. At the same time, three different evolution processes from double-well to unit-well were investigated. Also, optical dipole potential and photon scattering rate of the trapped cold atoms were calculated. The results show that the scheme not only is simple and convenient to realize, but also has wide application prospect in many fields, such as atomic physics, atomic optics, molecular optics and quantum optics.
Investigation of electromagnetic complex scattering for spherical targets in Ku wave band
Authors: Li Ying-Le  , Huang Ji-Ying  , Wang Ming-Jun
Published: December 2020

The electromagnetic interaction between spherical targets is researched. The second scattering field for a target is derived in detail. The complex scattering field and the bistatic radar cross section are presented respectively. The simulation results in Ku wave band show that the size of the principal target affects greatly both the forward and the backward scattering. The influence of the surrounding targets shows definite periodicity. The secondary scattering field diminishes with the increase of distance between the two targets. The nearer to the forward area the surrounding target is, the bigger its affect. The magnitude of the secondary scattering field is about 10-4 that of the first scattering field. The size of surrounding particles can be considered as stable and uniform when researching the electromagnetic interaction. This kind of interaction in three dimensions can be investigated easily by using the obtained result and coordinate transformation.
Study on wide-field fluorescence sectioning microscopy based on dynamic speckle illumination
Authors: Lin Hao-Ming  , Shao Yong-Hong  , Qu Jun-Le  , Yin Jun  , Chen Si-Ping  , Niu Han-Ben
Published: December 2020

In this paper, we present a novel wide-field fluorescence sectioning microscopy in which speckle patterns are produced on the sample for illumination. The speckle pattern is dynamically changed and a sequence of fluorescence images of the sample is recorded with a CCD camera. Due to a large variation of fluorescence intensity of the in-focus light compared to that of the out-of-focus light, special processing algorithms can be used to reconstruct the sectioned fluorescence image. We calibrated the system and studied the effect of the reconstruction algorithms on the system performance. Fluorescence sectioned images of a few biological samples were obtained. Our experiments showed that this wide-field fluorescence sectioning microscopy can be used to optically section tissue and has potential applications in the clinics.
The self-correlation performance of semiconductor lasers with optical feedback and optical injection
Authors: Fan Yan  , Xia Guang-Qiong  , Wu Zheng-Mao
Published: December 2020

Based on the rate equations describing the semiconductor lasers with optical feedback and optical injection, the influences of the feedback strength and delay time, injection strength and frequency detuning on the self-correlation performance of the output chaotic signal have been investigated. The results show that the full-width at half-maximum (FWHM) and peak sidelobe level of the output self-correlation function is critically dependent on parameters related to injection and feedback. Through reasonably selecting the parameters, the self-correlation function with 0.02ns FWHM can be obtained, which is superior to the reported results.
Research on flat ultra-wideband supercontinuum generated in dispersion-flattened decreasing fiber
Authors: Chen Yong-Zhu  , Li Yu-Zhong  , Xu Wen-Cheng
Published: December 2020

Different from the conventional model of dispersion-flattened decreasing fiber, a novel dispersion model of dispersion-flattened decreasing fiber is proposed and supercontinuum generation in is simulated and analyzed by utilizing the total field formation in the frequency domain. It is found that the supercontinuum generated in the latter is by far wider than that in the former and the flat bandwidth can be greater than 1000nm. It is further found that both the fiber parameters, such as peak dispersion, differential constant of the dispersion, and decreasing coefficient of the dispersion, and the pump pulse parameters, including pulse width, soliton order and frequency chirp, are crucial to the flat ultra-wideband supercontinuum generation in the fiber.
Simulation of the modulation instability in dual-core optical fiber based on complex Ginzburg-Landau equation
Authors: Ding Wan-Shan  , Xi Ling  , Liu Lian-Hua
Published: December 2020

Instability of the continuous-wave states in a dual-core optical fiber system is investigated based on the complex Ginzburg-Landau equation. The dual-core optical fiber system consists of an active nonlinear dispersive core and a linear passive core. The modulation instability (MI) conditions are found from linearized equations for small perturbations. Simulations of the full system demonstrate that the development of the MI in the former regime leads to the establishment of a regular or chaotic array of pulses if the MI saturates, or a chain of well-separated peaks with continuously growing amplitudes if the instability does not saturate. It indicates that the peak value of multiple return-to-zero (RZ) pulses or a single RZ pulse will be amplified and the RZ pulse sources emerge in the optical fiber in the anomalous group velocity dispersion regime. This research can be used as the resource of the optical fiber telecommunications and will be useful for the study of the fibre optics and physics and also in some other fields.
Control of attosecond pulse generation with modulated polarization gating
Authors: Zhang Qing-Bin  , Hong Wei-Yi  , Lan Peng-Fei  , Yang Zhen-Yu  , Lu Pei-Xiang
Published: December 2020

A new method is proposed to generate extreme ultraviolet supercontinuum. The polarization gating at 1600nm is employed to intensify the ellipticity dependence of high harmonic signal， and the addition of a second harmonic field is used for modulating the ionization ratio. Calculations show that a fundamental pulse up to 6 optical cycles (32.4fs) in duration can be applied to confine the efficient high harmonic generation to half an optical cycle. This feature allows us to produce an extreme ultraviolet supercontinuum with the bandwidth of about 280eV which supports generating a Fourier-transform-limited pulse of 10as. By selecting one part of the supercontinuum， a 100as pulse is obtained directly. In addition， the intensity utilizing efficiency of fundamental pulses can be increased by making the delay between the two pulses which compose the polarization gating smaller，when the modulated polarization gating is employed.
Structure and optical properties of wurtzite Mg0.25Zn0.75O film deposited on quartz glass substrate
Authors: Liu Quan-Sheng  , Zhang Xi-Yan  , Wang Neng-Li  , Wang Xiao-Chun  , Bai Zhao-Hui  , Mi Xiao-Yun  , Lu Li-Ping  , Yuan Dong-Fang
Published: December 2020

MgxZn1-xO has been an object of intense study as a novel photo-electronic function material in recent years. Mg0.25Zn0.75O film was prepared on quartz glass substrate by sol-gel method. Structure and optical properties of Mg0.25Zn0.75O film were studied both in theory and by experiment. The result indicates that Mg0.25Zn0.75O film has hexagonal wurtzite structure. The film is homogeneous and the average grain size is about 20nm. Absorption spectrum indicates that the absorption edge starts at 360nm and the corresponding forbidden band width is 3.83eV. The luminescence spectrum of the sample is composed of three peaks at 384.9， 444.8 and 533.6nm respectively and the peak of excitation spectrum is at 378nm. The crystal lattice of Mg0.25Zn0.75O film is increased， the forbidden band width is broadened and the ultraviolet and blue-green luminescence peaks red-shift about 59， 14 and 12.6nm， respectively， due to the interstitial defects introduced by the surplus Mg ions.