bluuebunny/crossref_metadata_2025 huggingface dataset:
Spectrum evolution of filamentation restricted by capillary in high pressure gas
Authors: Cao Shi-Ying  , Wang Ying  , Zhang Zhi-Gang  , Chai Lu  , Wang Qing-Yue  , Yang Jian-Jun  , Zhu Xiao-Nong  ,   (1)南开大学现代光学研究所，光电信息技术科学教育部重点实验室，天津  300071; (2)天津大学精密仪器与光电子工程学院超快激光研究室，信息技术科学教育部重点实验室，天津  300072; (3)天津大学精密仪器与光电子工程学院超快激光研究室，信息技术科学教育部重点实验室，天津  300072;北京大学信息科学技术学院，量子信息与测量教育部重点实验室，北京  100871
Published: December 2020

Filamentation with and without capillary restriction by focusing intense femtosecond pulses into the Argon-filled tube was experimentally studied in this paper. The results showed that the width of the broadened spectrum was affected by the input pulse energy and position of the capillary with respect to the filament. It was also indicated that the intensity of the short wavelength region of the spectrum was enhanced by the capillary restriction, which would be favorable to obtaining intense, monocycle pulses after compression.
Add/drop channel filter based on fiber-Bragg-grating-assisted coupler fabricated by asymmetric fused taper technology
Authors: Dong Xiao-Wei  , Pei-Li  , Jian Shui-Sheng  ,   北京交通大学光波技术研究所，北京  100044
Published: December 2020

All-fiber add/drop filter based on fiber-Bragg-grating (FBG) assisted coupler is compact and non-interferometric, which reduces the device's sensitivity to the grating position. By introducing the grating refractive modulation into the evanescent field coupling, the coupled-mode equation of FBG-assisted coupler is obtained and the influences of fiber mismatch on the filter spectra is investigated thoroughly. And a high-quality FBG-assisted filter is achieved by adjusting fiber structure parameters using asymmetric fused taper technology. The experimentally measured results are in good agreement with the numerical calculations.
Moltipactor discharge in a magnetically insulated transmission line oscillator
Authors: Hao Jian-Hong  , Ding Wu  , Dong Zhi-Wei  ,   (1)北京应用物理与计算数学研究所，北京  100088; (2)华北电力大学信息工程系，北京  100201
Published: December 2020

According to the structure characteristic of the magnetically insulated transmission line oscillator (MILO), a one-sided multipactor discharge model is present. Through the calculations of the susceptibility curves and phase focusing effect, the physical conditions of the multipactor discharge occurring in the MILO are analyzed. The results show that one-sided multipactor modes have a wider phase focusing range than two-sided modes, and there is many chances for electronic grazing incidence on the metal surface for MILO. So the multipactor discharge is more serious for MILO than O-type devices.
Effect of nanoscale C and SiC doping on the superconducting properties of MgB2 tapes
Authors: Zhang Xian-Ping  , Ma Yan-Wei  , Gao Zhao-Shun  , Yu Zheng-Guang  , K. Watanabe  , Wen Hai-Hu  ,   (1)日本东北大学金属材料研究所，仙台 980-8577，日本; (2)中国科学院电工研究所应用超导实验室，北京  100080; (3)中国科学院物理研究所，北京  100080
Published: December 2020

Nanoscale C and SiC doped MgB2 tapes were prepared by the in situ powder-in-tube method. The samples were characterized using X-ray diffraction, scanning electron microscope, superconducting quantum interference device magnetometer etc. Transport JC and its magnetic field dependence were evaluated by a standard four-probe technique. It is found that JC for all the C and SiC doped tapes was significantly enhanced in magnetic fields up to 14 T compared to the undoped ones. For the 5% C and SiC doped samples, at 4.2 K and 10 T, JC increased by a factor of 32 and 26, respectively. The improvement of JC-B properties in C and SiC doped MgB2 tapes is attributed to good grain linkage and the introduction of effective flux pining centers with the doping. Furthermore, our results clearly prove that the observed positive effects after mixing with SiC are nothing else than the result of the decomposition of this compound and substitution of carbon for B in MgB2.
Effect of pulsed magnetic field on critical current in carbon-nanotube-doped MgB2 wires
Authors: Chen Rong-Hua  , Zhu Ming-Yuan  , Li Ying  , Li Wen-Xian  , Jin Hong-Ming  , Dou Shi-Xue  ,   (1)上海大学材料科学与工程学院，上海  200072; (2)伍伦贡大学电子材料与超导研究所，伍伦贡  2522，澳大利亚
Published: December 2020

This study is about carbon-nanotube (CNT)-doping of MgB2 superconductor processed under the magnetic field. The Jc(H) for CNT doped sample increased by a factor of 2—3 in low filed and more than an order of magnitude in high field after processing in magnetic field. The alignment of CNT along the processing field direction was observed by SEM.
The magnetic and electronic transport properties in Ag-doped La-K-Mn-O inhomogeneous system
Authors: Wu Jian  , Zhang Shi-Yuan  ,   (1)河海大学理学院,南京  210098; (2)南京大学物理系,南京  210093
Published: December 2020

Microstructure, magnetic and electronic transport properties of the inhomogeneous system 1/m Ag2O-La0.833K0.167MnO3 (1/m is molar ratio, m=32, 16, 8, 4, and 2) have been studied. X-ray diffraction patterns show that all the samples are the two-phase composite and consist of a magnetic La0.833K0.167MnO3 (LKMO) perovskite phase and a nonmagnetic metal Ag phase. The room temperature magnetoresistance (MR) effect is enhanced significantly due to the addition of Ag. For the m = 4 sample the MR ratio increases from 10% of the pure compound LKMO to 32% under a lower field of 0.5 T and from ～35% of LKMO to 64 % under a higher field of 5.5 T at the temperature of 300 K. In the low temperature range from 4.2 K to 265 K, however, the MR ratio of the Ag-doped sample decreases with increasing the Ag content in the samples. The effect is discussed qualitatively by use of the relative change among the intrinsic MR effect and the extrinsic MR effect including the spin-polarized-tunneling and spin-dependent scattering effects at grain boundaries.
A piezomodulated reflectance study of InAs/GaAs surface quantum dots
Authors: Yu Chen-Hui  , Wang Chong  , Gong Qian  , Zhang Bo  , Lu Wei  ,   (1)中国科学院上海技术物理研究所，红外物理国家重点实验室，上海  200083; (2)中国科学院上海微系统与信息技术研究所，信息功能材料国家重点实验室，上海  200050
Published: December 2020

Piezomodulated reflectance (PzR) spectra have been measured for two samples of InAs surface quantum dots (SQDs) deposited on GaAs (311)B substrates with In0.35Ga0.65As template. At 77K multiple confined-state SQDs transitions can be clearly resolved from the PzR spectra . The detailed optical transition features of SQDs, QDs buried by capping layer, In0.35Ga0.65As template and GaAs substrate layers were obtained from well-fitted PzR spectra using the first or third derivative of a Lorentz line shape. Differences between PzR results of two samples were discussed qualitatively.
Preparation and luminescence characteristics of Eu2+ activated Ca3SiO5 green-emitting phosphor
Authors: Yang Zhi-Ping  , Liu Yu-Feng  ,   (1)河北大学物理科学与技术学院，保定  071002; (2)河北大学物理科学与技术学院，保定  071002;河北省保定市第一中学，保定  071002
Published: December 2020

The preparation and the luminescent properties of green-emitting phosphor Ca3SiO5:Eu2+ have been studied. The broad green emission band with the peak located at 502 nm which consists of a main and a subsidiary emission peak at 501nm and 570nm，respectively， originate from the centers of Eu2+ ions. There are two different Eu2+ emitting centers in Ca3SiO5:Eu2+, which has been confirmed by the experiment results and empirical formula of Van Uitert，and the Eu2+ ions occupy Ca2+ sites with coordination number 8 and 4 in this phase. The excitation spectra extend from 250 nm to 450 nm and the excitation peak positions are located around 375 nm. The phosphor can be excited effectively by InGaN chip emitting in the range of 350—410 nm.
Structure and photoluminescence of Er3+-doped Al2O3 composite powders by mixing with SiO2
Authors: Zhu Zhen-Hua  , Lei Ming-Kai  ,   大连理工大学材料科学与工程学院表面工程研究室,大连  116024
Published: December 2020

The 0.1 mol% Er3+-doped Al2O3 and SiO2-Al2O3 powders have been prepared by the sol-gel method. The results show that the addition of 5 mol% SiO2 into the Er3+-doped Al2O3 suppresses the phase transitions of γ→θ and θ→α. For the 0.1 mol% Er3+-doped Al2O3 powders at the sintered at temperature of 900℃, the broadband photoluminescence (PL) spectrum centered at 1.53 μm in the range from 1.47 μm to 1.63 μm was obtained with the full width at half maximum of 56 nm, and the splitted PL spectra appeared for powders sintered at 1000—1200℃. For the 0.1 mol% Er3+-doped Al2O3-SiO2 powders, the PL spectrum has a single broadband centered at 1.53 μm even when the sintering temperature is as high as 1200℃, and the PL intensity increases by one order of magnitude, because—OH group in the Al2O3-SiO2 powders has been removed completely, compared with that in the Al2O3 powders with and without mixing of SiO2 sintered at the temperature of 900℃.
Propagation properties of one-dimensional off-axis Gaussian beams through the turbulent atmosphere
Authors: Ji Xiao-Ling  , Tang Ming-Yue  ,   四川师范大学物理学院，成都  610066
Published: December 2020

The propagation properties of one-dimensional off-axis Gaussian beams through the turbulent atmosphere are studied in detail. The propagation equation of intensity is derived. It is shown that one-dimensional off-axis Gaussian beams in turbulent atmosphere undergo three stages of evolution with increasing propagation distance z, i.e., their saw-tooth beam profile is similar to the initial one in the near field, then becomes a flat-topped profile with increasing z, and at last turns into Gaussian-like profile in the far field. The turbulence accelerates the evolution of the stages which one-dimensional off-axis Gaussian beams undergo. Furthermore, the normalized intensity distributions of one-dimensional off-axis Gaussian beams with different beam numbers become close to each other due to turbulence. In addition, one-dimensional off-axis Gaussian beams with higher beam numbers are less sensitive to the effects of turbulence than those with lower beam numbers, and one-dimensional off-axis Gaussian beams are less sensitive to the effects of turbulence than Gaussian beams.
A TCML-based spatiotemporal chaotic one-way Hash function with changeable-parameter
Authors: Liu Jian-Dong  , Yu You-Ming  ,   北京石油化工学院信息工程学院，北京 102617
Published: December 2020

A TCML-based spatiotemporal chaotic one-way Hash function with changeable parameter was constructed based on the analysis of sensitivity to initial value and parameters of one-way and two-way coupled map Lattice(TCML) systems.The approach is implemented by employing part of the initial values of coupled map system as the secret key, and the parameters of two-way coupled map system in each iteration is dynamically determined by the value of the last iteration and the corresponding message bit in different positions，and then making message with multigrid embedded in spatiotemporal chaos track in parallel. Choosing some suitable spatial items of the result of the final iteration, the Hash value was obtained by means of linear transform limited with 128 bits.Iteration process has very strong irreversibility and sensitivity to initial values and parameters. Each bit of Hash value has very sensitive, complex and strongly nonlinear coupling relation with the corresponding message and secret key because of the bidirectional diffusion and confusion characteristics. Simulation and analysis demonstrate that the algorithm satisfies all the performance requirements of Hash function and is reliable，secure and efficient.
Partially Hamiltonization and integration of differential equations
Authors: Zhang Rui-Chao  , Wang Lian-Hai  , Yue Cheng-Qing  ,   山东省计算中心，济南  250014
Published: December 2020

The differential equations are expressed partially by the equations of Hamilton system and then they can be written in the contravariant algebraic form. The Poisson integration theory of the equations is presented and an example is given to illustrate the application of the result.
Effect of solute atoms and precipitated phase in Al-4.5wt% Cu alloys on the spatiotempopal characteristics of the serrated yielding
Authors: Sun Liang  , Zhang Qing-Chuan  , Yan Shun-Ping  , Jiang Hui-Feng  , Liu Hao-Wen  , Lu Jun-Yong  , Wu Xiao-Ping  ,   中国科学技术大学,中国科学院材料力学行为和设计重点实验室,合肥 230027
Published: December 2020

It is well accepted that the interaction between solute atom and precipitated phase leads to dynamic strain aging (DSA). In this research solution treatments at different temperatures are adopted to control the solute concentration in solid solution and precipitated phase content in the Al-4.5wt%Cu alloy material, and their influences on dislocation movement are analyzed by subsequent tensile experiments on these treated material specimens, and the corresponding micro-mechanism of DSA is discussed. It is found that, when the solution treatment temperature is reduced stepwise from 500℃, the amplitude of the serrated yielding decreases until it reaches a minimum at 300℃, whereas the amplitude begins to increase as the solution treatment temperature is reduced continually to 100℃. Meanwhile, the heat-treatment also affects the propagation characteristics of shear bands. The experimental results also show that, when the solution treatment temperature is higher than 300℃, the solute concentration is the key factor influencing DSA. However, when the solution treatment temperature is lower than 300℃, the intensity of DSA is determined by precipitated phase density. In the case of room temperature, the micro-mechanism of DSA is found to be primarily governed by precipitated phases.
Study on threshold voltage model of strained SiGe quantum well channel SOI PMOSFET
Authors: Zhang He-Ming  , Cui Xiao-Ying  , Hu Hui-Yong  , Dai Xian-Ying  , Xuan Rong-Xi  ,   (1)西安电子科技大学微电子学院，宽禁带半导体材料与器件教育部重点实验室，西安 710071; (2)西安电子科技大学微电子学院，宽禁带半导体材料与器件教育部重点实验室，西安 710071;中国电子科技集团第五研究所分析中心，广州 510610
Published: December 2020

A SOI PMOSFET with SiGe quantum well channel was formed by growing the SiGe film on the Si SOI structure. Not only does the device have the advantage of SOI structure, but also the performance of the device is improved because the carrier mobility in SiGe quantum well is much higher than that in Si. In this paper, the threshold voltage model of strained SiGe SOI quantum well channel PMOSFET is established on the basis of general Si SOI MOSFET, also the model of voltage-current characterisfic is founded. The characteristic of voltage-current, transconductance and leak conductance were simulated and analyzed using MATLAB. The results of the simulation confirm that the strained SiGe SOI quantum well channel PMOSFET performs much better than the conventional PMOSFET.
Research on the dye-sensitized solar cell module
Authors: Weng Jian  , Xiao Shang-Feng  , Chen Shuang-Hong  , Dai Song-Yuan  ,   中国科学院等离子体物理研究所，太阳能材料与工程研究室，合肥 230031
Published: December 2020

We have investigated experimentally the effect of series resistance to the dye-sensitized solar cell, and found a very effective way to improve the performance of the dye-sensitized solar cell. We have obtained a photo-electric conversion efficiency of 6.89% with the strip cell (active area:0.8×18cm2), and 5.7% with the module(15×20cm2). It is an encouraging step forward in the research on the dye-sensitized solar cell module, and it may provide the theoretical basis as well as experimental data for future applications.
Analysis of similarity of several proxy series based on nonlinear analysis method
Authors: Gong Zhi-Qiang  , Feng Guo-Lin  ,   (1)国家气候中心，中国气象局气候研究开放实验室，北京 100081;中国科学院大气物理研究所东亚区域气候-环境重点实验室，北京 100029; (2)兰州大学大气科学学院，兰州 730000;国家气候中心，中国气象局气候研究开放实验室，北京 100081
Published: December 2020

Reconstruction and analysis of proxy series is an important program of climate research. Using methods of wavelet transformation and power spectrum, the main periods of Dulan tree ring and other 7 temperature proxy series are analyzed in this paper. Through filtering, the 8 original series were divided into many different scale components, the similarities in dynamics and external features of components on each scale are studied based on the dynamical correlation factor exponent and correlation coefficient. Research results show that quasi 100a scale might be the common period of these proxy series, meanwhile, both dynamics and external features of these proxy series are similar on the quasi 100a and even higher scales. This means that the quasi 100a and even higher scale components meet with comparable conditions in these aspects. More attention must be paid to this scale when analyzing proxy series. We also found that the similarities in dynamics and external features of these proxy series are reduced as the scale of the components decreaces; On quasi 60—70a scale, the component similarities in dynamics features disappear. On quasi 30a and even lower scale the similarities of external features also disappear.
Singular solitons of generalized Camassa-Holm models
Authors: Sun Lu  , Tian Li-Xin  ,   江苏大学非线性科学研究中心，镇江 212013
Published: December 2020

In this paper we introduce one type of generalized dispersive Camassa-Holm model and make its singularity analysis. We prove that the model is Painlevé integrable by an alternative WTC-Kruskal test and obtain the Painlevé-Bcklund systems and the Bcklund transformation. Many new types of regular soliton, singular soliton, kink soliton, compacton and anti-compacton are explored. Particularly, we have found singular structures of periodic cuspon waves in kink solitons, which occur in their central regions. Based on the regular solitonic system, we do Bcklund transformation and obtain three sorts of singular solitons, namely the periodic blow-up wave with hump structure, kink soliton for the blow-up wave structure and the compacton.
Stability of nonlinear dynamical system of relative rotation and approximate solution under forced excitation
Authors: Shi Pei-Ming  , Liu Bin  ,   燕山大学信息科学与工程学院，秦皇岛 066004
Published: December 2020

The stability of nonlinear dynamical system of relative rotation is studied. Firstly, the dynamics equation of relative rotation autonomous nonlinear dynamical system with commonly damped force and forced excitation is deduced. Secondly, the stability of relative rotation nonlinear dynamical system is studied. For the nonlinear dynamical system, it is proved that the closed orbit bifurcation can occur under some conditions. Finally, The approximate solution of the equation under forced excitation is obtained by the method of multiple scales.
Microstructures of Al and Cu interconnects
Authors: Wang Jun-Zhong  , Ji Yuan  , Wang Xiao-Dong  , Liu Zhi-Min  , Luo Jun-Feng  , Li Zhi-Guo  ,   (1)北京工业大学电控学院，北京  100022; (2)北京工业大学固体微结构与性能研究所，北京  100022; (3)中国人民武装警察部队学院基础部物理教研室，廊坊  065000
Published: December 2020

The electron backscatter diffraction technique (EBSD) has been used to measure the microstructure of reactive ion etched(RIE) Al and damascene Cu interconnects, including the grain size, grain orientation and grain boundary characteristics. Linewidths of Cu interconnects, as well as the anneal processes of Al and Cu interconnects impacting on the microstructures and causing the electromigration failure were analyzed.
Conformal dome aberration correction with diffractive elements
Authors: Sun Jin-Xia  , Sun Qiang  , Li Dong-Xi  , Lu Zhen-Wu  ,   (1)中国科学院长春光学精密机械与物理研究所，应用光学国家重点实验室，长春 130033; (2)中国科学院长春光学精密机械与物理研究所，应用光学国家重点实验室，长春 130033;中国科学院研究生院，北京 100049
Published: December 2020

Conformal dome may enhance the velocity and effective range of the missile systems by providing better aerodynamical surfaces than traditional domes. However，the highly aspheric surface may introduce serious aberration which changes with the field of regard，and the fixed corrector can be used to correct these higher aberrations in the big field. This paper analysis the performance of the conformal dome and proposes a way for the optical corrector design by adding diffractive element into the fixed corrector. The simulation proves it's an effective way to improve the imaging quality of the conformal dome.
Study of Nd3+-doped polarization-maintaining fiber laser
Authors: Ren Guang-Jun  , Zhang Qiang  , Wang Peng  , Yao Jian-Quan  ,   天津大学精密仪器与光电子工程学院，激光与光电子研究所；天津大学光电信息科学技术教育部重点实验室，天津 300072
Published: December 2020

By means of numerical analysis，the distribution of pump light and the output laser power along the fiber with different fiber length has been investigated. The experimental research of the Nd3+-doped polarization-maintaining fiber laser is reported，which is pumped by 808nm semiconductor laser. The influence of different fiber winding radius on output power and polarization characteristic of the laser are studied. Double wavelength peaks at 1060nm and 1092nm are obtained. The maximum output power of the laser is 7.35W at 1060nm，the slope efficiency is 58.3%.
Diagnosis of electron density in spot-focused CH plasma with X-ray Laser M-Z interferometer
Authors: Zheng Wu-Di  , Zhang Guo-Ping  , Wang Chen  , Sun Jin-Ren  , Fang Zhi-Heng  , Gu Yuan  , Fu Si-Zu  ,   (1)北京应用物理与计算数学研究所，北京 100088; (2)北京应用物理与计算数学研究所，北京 100088;中国工程物理研究院研究生部，北京 100088; (3)上海激光等离子体研究所，上海 201800
Published: December 2020

A soft X-ray laser Mach-Zehnder interferometer was used to diagnose electron density Ne of spot-focused CH plasma on Shengguang II facility, and the experimental results were presented in this paper. Density reconstruction was performed by making Abel transform, 2D distribution of Ne was obtained, and the highest Ne was about 3.2×1021cm-3. Comparing with simulation results of JB19 code (1.5D) and XRL2D code (2D), it was found that the theoretical result with flux-limited factor of 0.05 agreed with reconstructed result in high density area, but experimental result gave an Ne distribution declining faster. Furthermore, 2D Ne distribution of simulation differed much from that of experiment in details. A brief error analysis showed that flatness error of interferometer dominated the experimental error.
Effect of bulk inclusion in films on damage probability
Authors: Xia Zhi-Lin  , Shao Jian-Da  , Fan Zheng-Xiu  ,   (1)中国科学院上海光学精密机械研究所，上海  201800; (2)中国科学院上海光学精密机械研究所，上海  201800;中国科学院研究生院，北京  100080
Published: December 2020

From the relation between damage probability and density of surface inclusion, combining with the test results of XRD and laser induced damage, we have drawn a conclusion that bulk inclusions dominate the damage in these experiments. Combining thermal and mechanical processes of inclusion absorption and the statistical rule of inclusion density, we have deduced an equation describing the relation between damage probability and density of inclusions, power density of laser pulse, as well as thickness of films. From the model in this paper, we can see that the range of siges in which the inclusions can initialize damage alter with the depth of inclusions. So density of the dangerous inclusions in different depth is different. The results from theory and from experiments are identical. This model can also interpret damage morphology.
Mesostructure investigation of the transverse magnetic anisotropy field in stress-annealed Fe-based nanocrystalline ribbons
Authors: Shi Fang-Ye  , Fang Yun-Zhang  , Sun Huai-Jun  , Zheng Jin-Ju  , Lin Gen-Jin  , Wu Feng-Min  ,   (1)浙江师范大学数理与信息工程学院,金华 321004; (2)浙江师范大学数理与信息工程学院,金华 321004;浙江师范大学物理化学研究所,金华 321004
Published: December 2020

The mesostructure in Fe-based (Fe73.5Cu1Nb3Si13.5B9) nanocrystalline ribbons annealed under different stress (FNRAS) was investigated by observation of the cross section images of the ribbons with atomic force microscopy (AFM) and X-ray diffraction. The longitudinally driven giant magneto-impedance and transversal magnetic anisotropy field (Hk) were measured. The mechanism of the transversal magnetic anisotropy field can be explained by the mesostructure of the directional preference of crystalline grain (coated with amorphous shell) gathering, along the transverse direction, induced in the course of annealing of the Fe-based alloy ribbons under stress.
Molecular dynamics simulation of the diffusion bonding and tensile behavior of a Cu-Al interface
Authors: Liu Hao  , Ke Fu-Jiu  , Pan Hui  , Zhou Min  ,   (1)北京航空航天大学物理系，北京  100083;中国科学院力学研究所非线性力学国家重点实验室，北京  100080; (2)美国乔治亚理工学院机械工程学院及材料科学与工程学院，乔治亚  30332-0405
Published: December 2020

In this paper, we use molecular dynamics simulations to study the diffusion bonding of a Cu/Al interface. The interface analyzed is that between atomically smooth (001) crystalline planes of a Cu and an Al single crystals. The thickness of the transition layer of the bonded interface is obtained. The structural change of the interfacial region under different cooling rates is analyzed by means of the radial distribution function (RDF) and the pair analysis techniques. The interface assumes an amorphous structure upon initial mechanical pressing and remains amorphous if the subsequent cooling rate is high. At lower cooling rates, however, the interface structure becomes crystalline. The diffusion-bonded Cu/Al specimen is subjected to tensile loading and its strength is compared with those of single-crystalline Cu and single-crystalline Al of the same size along the same direction. Calculated results indicate that the specimen with the interface has a lower tensile strength and a lower ductility than the corresponding single-crystalline Cu and Al specimens.
Electronic theory of interface characteristics of ZA27/CNT
Authors: Liu Gui-Li  , Guo Yu-Fu  , Li Rong-De  ,   沈阳工业大学建筑工程学院，沈阳 110023
Published: December 2020

The interface binding energy has been defined according to the atomic binding energy. The interface electronic structures of ZA27/CNT have been calculated by recursive method in zinc-aluminum composite reinforced by carbon nanotube. The microphysics of carbon nanotube distribution at grain boundaries of ZA27 alloy and the cause of weak interface binding in ZA27/CNT at electronic level were made clear. The research showed that the metal matrix has great effect on the density of states of carbon atoms on the nanotube, but the nanotube has little effect on the density of states of aluminum or zinc atoms in the matrix. The density of states of carbon on nanotube tends to become assimilated with matrix atoms and combine with the matrix, but as the assimilation degree is low, the interface binding strength is very weak. It is believed that similar property of atoms with matrix decorating or plated on carbon nanotube may help to reinforce the interface binding strength and improve the performance of ZA27 composite.
Molecular dynamics simulation of fracture in α-iron
Authors: Cao Li-Xia  , Wang Chong-Yu  ,   (1)钢铁研究总院功能材料所，北京  100081; (2)清华大学物理系，北京  100084;钢铁研究总院功能材料所，北京  100081
Published: December 2020

The deformation process of the crack in α-Fe has been simulated under uniaxial tensile deformation by molecular dynamics (MD) method. The effect of crystal orientations on the deformation mechanisms of the crack has been investigated. Various deformation evidences are clearly observed, such as dislocation nucleation and emission, dislocation movement，stacking faults formation or twinning， and formation and coalescence of voids. The simulated results indicate that the crack propagate by a combination of plastic and elastic processes in which the plastic portion of the crack results from the shear behavior of atoms created by the dislocations that are emitted from the crack tip, and the elastic process occurs as a result of the bond-breaking of the atoms in the dislocation-free zone. It has also been studied the deformation and fracture characteristics of the crack in α-Fe and their dependence on the stress state and the temperature.
Instantaneous relaxation of photoconductivity in GaN film grown on vicinal sapphire substrate by MBE
Authors: Yuan Jin-She  , Chen Guang-De  ,   (1)西安交通大学理学院,西安 710048; (2)重庆师范大学物理学与信息技术学院，重庆 400047;西安交通大学理学院,西安 710048
Published: December 2020

By optimizing the technique and conditions experimentally, we have grown GaN film on vicinal sapphire (0001) substrates by radio frequency plasma-assisted molecular beam epitaxy (MBE). It was found that the films grown on vicinal sapphire (001) substrates have better quality than that grown on conventional substrate, as shovn by XRD and AFM characterization. Through investigation of the instantaneous relaxation behaviors of photoconductivity in GaN films grown on vicinal and common sapphire substrates, three stages of carrier recombination in the conventional MBE GaN film were discovered. The stages consist of bimolecular, monomolecular and persistent recombination phases in which the relaxation times are 0.91, 7.7 and 35.5ms, respectively. In comparison, only bimolecular and monomolecular recombination processes of photo-generated carriers were found in the GaN film grown on vicinal sapphire (0001) substrate, the relaxation time was measured to be 0.78 and 14 ms, respectively. Theoretical considerations directly show that the persistent conductivity mainly originates from the native dislocation defects in GaN film grown by MBE.
A delayed failure of inhomogenous brittle material under shock wave compression
Authors: Chen Deng-Ping  , He Hong-Liang  , Li Ming-Fa  , Jing Fu-Qian  ,   (1)武汉理工大学理学院，武汉  430070; (2)中国工程物理研究院流体物理研究所冲击波物理与爆轰物理重点实验室，绵阳  621900; (3)中国工程物理研究院流体物理研究所冲击波物理与爆轰物理重点实验室，绵阳  621900;武汉理工大学理学院，武汉  430070
Published: December 2020

The failure property of inhomogenous brittle materials under plate impact experiment has been studied by using AOW (amphibolized olivine websterite) rock as a representative sample. A small recompression signal was observed in the VISAR record of the rear free surface velocity at shock stress much below σHEL, indicating the generation of the failure wave. By using samples with different thickness but impacted at approximately the same shock stress of 3.9 GPa, the trajectory of the propagation of the failure wave through the stressed sample has been determined. The failure wave is generated with a delay time of about 0.5 μs behind the shock wave front, and propagates into the stressed material with a velocity comparable to that of the shock wave front. A physical mechanism involving the “in situ activation and growth” of the originally existing micro-cracks due to the local shear stress under shock wave compression is suggested for these observations.
Preparation and properties of the organic nonlinear optical crystal trans-4-［4-(dimethylamino) styryl］-1-methylpyridium p-toluenesulfonate
Authors: Niu Rui-Qi  , Dong Hui-Ru  , Wang Yun-Ping  ,   (1)北京化工大学理学院，北京 100029; (2)北京化工大学理学院，北京 100029;中国科学院物理研究所，北京 100080; (3)中国科学院物理研究所，北京 100080
Published: December 2020

The organic ionic salt of trans-4-［4-(dimethylamino) styryl］-1-methylpyridium p-toluenesulfonate (DAST) is a kind of nonlinear optical crystal. Large and high-quality DAST crystals were grown in a saturated DAST-methanol solution from seed crystals by controlling the temperature. The effects of preparation method, temperature and cooling speed on the growth of DAST crystals were investigated in detail. The light transmittance and thermal stability of prepared DAST crystals were studied. The sample of DAST crystal heated at 265℃ was characterized by X-ray diffraction (XRD) and Fourier transformation infra-Red spectroscopy (FT-IR), and it was proved that the phase transition temperature of DAST crystal is 260℃, and it is feasible to prepare DAST crystal from the melt. At the same time, the process of weight loss of DAST crystal at 37—800℃ was discussed preliminarily.
Analysis of wavefront measuring method for daytime adaptive optics
Authors: Li Chao-Hong  , Xian Hao  , Jiang Wen-Han  , Rao Chang-Hui  ,   (1)中国科学院光电技术研究所,成都 610209; (2)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

Two field-of-view shifted Shack-Hartmann wavefront sensors (FSWFS) are proposed, which are used to measure the wavefront information of object signal under daytime conditons. The experimental results on the sky background's non-uniformity characteristics are obtained, the detecting error of the dual focal-plane FSWFS is analyzed in this paper and its principle has been proven by experiments with a single focal-plane array. The measuring results indicate that FSWFS can precisely and stably measure the wavefront information of object signal with strong background. At the same time, the detection capacity of FSWFS is estimated and its restraining factors are analyzed, and the estimation results show that the adaptive optics system with FSWFS in Yunnan observatory can precisely measure the wavefront information of object signal whose V magnitude is 5 when the brightness of the sky background is 10 W/m2·sr.
A study of the light curve periodic behavior of BL Lac object S5 0716+714
Authors: Zhang Hao-Jing  , Zhang Xiong  ,   (1)云南师范大学物理系，昆明 650092; (2)中国科学院国家天文台，北京 100012
Published: December 2020

From a large volume of literature we have collected a total of 16818 datapoints of effective observation of BL Lac object S5 0716+714 in the optical band, and constructed its long-term light curve from 1994 to 2006 AD. The light curve shows that S5 0716+714 is very active and exhibits very complicated non-sinusoidal variations. We used power spectrum method to analyze the period of light curve variation. Our results show that the long-term period of variation is 1.1 year. Time of coincidence is possible, Raiteri et al. have found the period of 3.3 year, which may be a multiple of 1.1-year periods. We expect next burst in 2006 July.
Fidelity of the scheme of continunous variables quantum teleportation via minimum-correlation mixed quantum states
Authors: Xia Yun-Jie  , Wang Guang-Hui  , Du Shao-Jiang  ,   (1)济宁师范专科学校物理系，曲阜 273155; (2)曲阜师范大学物理工程学院，曲阜 273165
Published: December 2020

Based on the proposal of Braunstein and Kimble，we studied the continuous variables quantum teleportation via minimum-correlation mixed state. The results show that the mixed entangled state as a generalized type of Einstein-Podolsky-Rosen entangled states is a good quantum channel. As an example，we analyzed in detail teleporting a coherent state by means of this channel. When the parameters of minimum-correlation mixed state are chosen properly，the fidelity will almost reach to unity. The minimum-correlation mixed state as a quantum channel is better than the two-mode squeezed vacuum state.
State-dependent Riccati equation synchronization method of unified chaotic system
Authors: Shan Liang  , Liang Yan  , Li Jun  , Wang Zhi-Quan  ,   (1)南京理工大学电子工程与光电技术学院，南京 210094; (2)南京理工大学自动化学院，南京 210094
Published: December 2020

Using improved state-dependent Riccati equation method，the state synchronization of unified chaotic systems is achieved. The state adjustors with given stability improve the dynamic performance of system synchronization. Theoretical deduction and simulation researches show that the error systems are asymptoticly stable. The comparative simulations with the traditional state-dependent Riccati equation method verify the improvement in dynamic performance of system synchronization.
Mass spectrum of laser ionized diethyl ether clusters studied with ab initio calculation
Authors: Wang Yan  , Zhang Shu-Dong  , Zhu Xiang-Jun  , Kong Xiang-He  ,   曲阜师范大学物理工程学院，曲阜 273165
Published: December 2020

Diethyl ether clusters were studied using both laser multiphoton ionization mass spectrum and supersonic pulsed molecular beam technique. Only less intensity ions of (E)H+, (E)＋2 and (E)2H+(E stands for CH3CH2OCH2CH3), accompanying with some stronger fragmented ions of diethyl ether, were observed. Using ab initio calculation to optimize the geometric structure and calculate the energy of diethyl ether clusters at B3LYP/6-311++G(d,p) level, the results show that the most stable structure of (E)2 is a six-side-like ring, in which the oxygen atom and the ethyl group of one molecule are located close to the ethyl group and the oxygen atom of another molecule, respectively. The binding energy of (E)2 is 9.35meV when considering the basis set superposition error with counterpoise method, which is equivalent to the dipole-dipole interaction between the partners. Comparing with the binding energy 221.93meV of complex (CH3CH2OCH2CH3)-H2O, which is associated by hydrogen bonding, it is suggested that the diethyl ether clusters are formed by weak dipole-dipole interaction and the initially formed dimmer acts as a seed for further cluster growth, meanwhile, as the binding energy decreases with size increasing, so larger clusters are not easily observed in experiment.
Some nonclassical properties of a finite dimensional even and odd pair coherent state
Authors: Meng Xiang-Guo  , Wang Ji-Suo  ,   聊城大学物理系,聊城 252059
Published: December 2020

The exponential form of even and odd pair coherent state (EOPCS) is constructed. The EOPCS is generalized to a finite dimensional EOPCS in the Hilbert space, and then its orthonormalized property, completeness relations and some noncalssical properties are discussed. It is shown that the finite dimensional EOPCS has normalized and completeness relations, but not orthogonal relations. By virtue of the numerical computation method, we find that, for any value of q, in different ranges of the parameter |ξ| the 5-dimensional EOPCS for the modes 1 and 2 exhibit anti-bunching effect and the photons between the two modes are always correlated. The different peak structures of the phase probability distributions for the 7-dimensional EOPCS show remarkably different quantum interference properties.
Analysis of the property of the beam after spectral beam combining
Authors: Zhang Yan  , Zhang Bin  , Zhu Song-Jun  ,   四川大学电子信息学院，成都 610064
Published: December 2020

A propagation model for spectral beam combining is set up in this paper. First, using ray tracing method, the phase change induced by the blazed grating is expressed with the optical path differences in the groove and between grooves and the calculation model for the phase change of the beam obliquely incident on the grating is constructed. Then, using the diffraction integral method and the principle of incoherent superposition, the analytical expression for the output field of each emitter after passing through the spectral beam combining system is given and the intensity distribution of combined beam is calculated. Finally, using to the intensity second-order moments method, the M2-factors of the array beam and the combined beam are calculated and the effect of the system parameters on the characteristics of the combined beam is analyzed quantitatively. The results show that the M2-factor of the combined beam after passing through the spectral beam combining system remains almost the same as that of an individual emitter. The spacing of center wavelength between each emitter decreases with the increasing focal length of the transforming lens, resulting in the narrower spectrum width of the combined beam. The encapsulation error of the array elements has relatively little effect on the intensity distribution of the combined beam, whereas the position error of the array source has relatively greater effect on the combined beam.
The strain distribution and equilibrium morphology of Ge/Si semiconductor quantum dot
Authors: Cai Cheng-Yu  , Zhou Wang-Min  ,   浙江工业大学机电工程学院，杭州 310032
Published: December 2020

The dependence of total strain energy of a pyramidal self-assembled Ge/Si semiconductor quantum dot on the aspect ratio, is investigated. The free energy consisting of the strain energy and surface energy is defined, and used to study the equilibrium shape of the systems. The results show that the strain energy of thesystem decreases with the increasing aspect ratio, and under the requirement ofminimum total free energy, the quantum dot with a given volume will take a particular height-to-width aspect ratio,i.e.the equilibrium aspect ratio. Meanwhile, the distributions of the stress, hydrostatic strain and biaxial strain are presented. These can serve as a basis for interpretation of experiments on strain self-assembled quantum dots.
An adaptive approach based on Bernstein polynomial to predict chaotic time series
Authors: Yan Hua  , Wei Ping  , Xiao Xian-Ci  ,   电子科技大学电子工程学院,成都 610054
Published: December 2020

In this paper, we propose an approach using the Bernstein polynomial to model the dynamics of chaotic time series. Combining it with RLS algorithm, we can predict the chaotic time series adaptively. Theoretical analysis and computer simulation have demonstrated that this approach can provide high precision and satisfactory percentage of prediction for some typical chaotic time series. Because of the fast convergence of RLS algorithm, this approach can be applied to predicting short record chaotic time series in real time.
Structure and magnetic properties of Co80Cr20/Ti90Cr10 film prepared by pulsed-laser deposition
Authors: Zeng Fan-Hao  , Zhang Xiao-Zhong  ,   清华大学材料科学与工程系先进材料教育部重点实验室,北京  100084
Published: December 2020

Ti90Cr10 and Co80Cr20/Ti90Cr10 thin films were prepared by pulsed laser deposition on Si (100) substrate at various temperatures. The relations between crystal structure and substrate temperature were investigated by XRD and the result revealed that as the substrate temperature increased, the film changed from amorphous state to crystal state gradually. Furthermore, the grain size and lattice parameters of Ti90Cr10 film were measured by the XRD spectrum. The surface and cross-sectional morphology of Ti90Cr10 film were characterized by TEM. The hardness, as well as boundary adhesion strength of the Ti90Cr10 film was measured by nano-indenter and the result indicates that increase of the substrate temperature is beneficial to increasing the adhesion of the film. The magnetic properties of Co80Cr20/Ti90Cr10 film were studied by VSM and the coercivity was observed to increase with decreasing film thickness. For the Co80Cr20(8nm)/Ti90Cr10(14 nm) film prepared at substrate temperature of 600℃ in vacuum，its coercivity is 65.25 kA/m and the squareness is about 0.86. Finally, the magnetization properties of the Co80Cr20/Ti90Cr10 are also discussed.
Enhanciement of exchange bias with diluted antiferromagnets in FM/AFM bilayers
Authors: Ma Mei  , Cai Lei  , Wang Xing-Fu  , Hu Jing-Guo  ,   扬州大学物理科学与技术学院,扬州  225002
Published: December 2020

Based on Monte Carlo method, the characteristic of exchange bias is discussed in diluted antiferromagnets in FM/AFM bilayers by changing the dilute concentration. The simulation results show that the exchange bias in FM/AFM bilayers can be enhanced significantly by introducing nonmagnetic atoms into the AFM layers. And there is a maximum in the diagram of exchange bias as a function of the dilute concentration, i.e., the exchange bias at first increases then decreases with increasing concentration of dilution at the same temperature. Besides, the maximum of the exchange bias occurs at lower concentration for higher temperature. These are consistent with the results of Phys. Rev. Lett. 96 117204 (2006). The cause of these results is that the spin distribution and the magnetic domain structure change greatly when varying dilute concentration. The exchange bias is maximal when the positive and the negative magnetic domains form a connected network. In addition, at the same concentration of dilution, by comparing the results of the random and regular dilution, we find that the exchange bias are more strongly increased by regular dilution than by random dilution for the FM/AFM bilayers, which shows further that the characteristic of exchange bias in FM/AFM bilayers depends on the interface spin-microstructure.
Influence of selenization on the surface morphology and phase structure of CuInSe2 thin films
Authors: Li Jian  , Zhu Jie  ,   北京科技大学新金属材料国家重点实验室，北京  100083
Published: December 2020

Co-sputtered Cu-In precursors were used as the backing materials, and selenium powder was employed as the raw materials. Five kinds of representative or innovative selenization schemes, including single selenium source, double selenium source, powder spraying, selenizing and annealing step by step or simultaneously, were applied to grow CuInSe2(CIS) thin films. The influence of selenium source location and temperature rising methods on the property of CIS films was evaluated. The similarities and differences in the morphology, composition and phase structure among different methods were compared. The relationship between selenization temperature, anneal temperature, anneal time and the composition of CIS thin films was researched. The rules how element percent alters with the selenization and anneal condition are established, which can provide a reference to better control the composition and phase structure of CIS thin films.
High-sensitivity fast neutron radiography system
Authors: Zhang Fa-Qiang  , Yang Jian-Lun  , Li Zheng-Hong  , Zhong Yao-Hua  , Ye Fan  , Qin Yi  , Chen Fa-Xin  , Ying Chun-Tong  , Liu Guang-Jun  ,   (1)核物理与化学研究所,绵阳  621900; (2)清华大学工程物理系,北京  100084; (3)清华大学工程物理系,北京  100084；核物理与化学研究所,绵阳  621900
Published: December 2020

Introduced in this paper is a fast neutron radiography system, which is mainly composed of a scintillation fiber array and a scientific grade optical CCD. The 14 MeV neutrons produced by deuterium-tritium fusion reactions, penetrate through objects and fall into a 50 mm×50 mm scintillation fiber array, and the neutron radiation is converted to green light (496 nm). The array has a length of 100 mm, consisting of 100×100 square scintillation fibers each with a cross-section of 500 μm×500 μm. For 14 MeV neutrons, the detection efficiency is as high as 21.4%. To avoid direct radiation from neutrons, the CCD is coupled to the array by a mirror and lens optics. By taking into account the factors affecting image quality, the resolution is estimated to be 1.5 mm. Several neutron radiographs have been obtained successfully in experiments carried out on K400 neutron generator.
Multiparty controlled quantum secure direct communication protocol
Authors: Wang Jian  , Chen Huang-Qing  , Zhang Quan  , Tang Chao-Jing  ,   国防科学技术大学电子科学与工程学院，长沙  410073
Published: December 2020

Based on the order rearrangement of single photon sequence, we present a multiparty controlled quantum secure direct communication protocol. The present protocol can be applied to some special scenario. In the protocol, the sender's secret message can only be recovered by the receiver under the permission of all the controllers. The security for the protocol is ensured by the quantum no-cloning theorem and the secret transmitting order of the single photon sequence. Moreover, all photons are used to encode the secret message except those chosen for eavesdropping check and it is unnecessary for the protocol to use entanglement. Our protocol is efficient and practicable.