bluuebunny/crossref_metadata_2025 huggingface dataset:
Specific heat of single-crystal NdMnO3
Authors: Cheng Jin-Guang  , Sui Yu  , Qian Zheng-Nan  , Liu Zhi-Guo  , Huang Xi-Qiang  , Miao Ji-Peng  , Lü Zhe  , Wang Xian-Jie  , Su Wen-Hui  ,   (1)哈尔滨工业大学理学院应用物理系凝聚态科学与技术研究中心，哈尔滨  150001; (2)哈尔滨工业大学理学院应用物理系凝聚态科学与技术研究中心，哈尔滨  150001；中国科学院国际材料物理中心，沈阳  110015
Published: December 2020

The temperature and field dependences of the specific heat of single-crystal NdMnO3 were investigated from 2K to 200K under different fields up to 8 T.Corresponding to the Type-A antiferromagnetic (A-AF) phase transition in the Mn sub-lattice,the specific heat under zero field exhibited a sharp λ-shaped peak at about 85K,which was depressed and broadened and changed smoothly with the increa se of magnetic field.But the entropy change due to the magnetic order is only 26% of the expected value,which might arise from the extension of the magnetic flu ctuation in a larger temperature range.The specific heat curves exhibited a shou lder-shaped Schottky-like anomaly below 20K,whose maximum shifts gradually to higher temperatures with the magnetic field.By considering the contributions to the specific heat at low temperatures,the above phenomena can be interpreted in terms of the model of effective molecular field (Hmf) at Nd 3+ site that causes the splitting of the ground state doublet (GSD) of Nd3+.The specific heat below 20K under different magnetic fields was successfully fitted,through which the meaningful parameters,including the splitting of the GSD of Nd3+,Debye temperature and the A-AF spin wave stiffness coefficient s,as well as their field dependence were obtained.It was found that the ferromagnetic component of the Mn sub-lattice caused by the GdFeO3-type octahedron ro tation could be the origin of the Hmf.
Magnetic properties of electrodeposited Fe and FePd nanowire arrays
Authors: Hu Hai-Ning  , Chen Jing-Lan  , Wu Guang-Heng  , Chen Li-Jie  , Liu He-Yan  , Li Yang-Xian  , Qu Jing-Ping  ,   (1)河北工业大学材料学院，天津  300130; (2)中科院物理研究所 北京凝聚态物理国家实验室，北京  100080
Published: December 2020

Fe and FePd nanowires were fabricated by electrodeposition in porous anodic aluminum oxide template. Both Fe and Fe0.95Pd0.05 nanowires have a (110) preferred orientation with a diameter of 60nm . This diameter is suitable f or investigating the behavior of traced Pd in FePd nanowire. With the traced Pd alloying in Fe nanowire, the crystalline anisotropy overpowers the shape anisotr opy, changing the magnetic domain structure and increasing the pinning of domain wall. Thus the Fe0.95Pd0.05 nanowire shows a str ong parallel-to-the-wire anisotropy with improved squareness and coercivity.
Ultrasonic studies of the spin-state transition and the local distortion in LaCoO3
Authors: Zhang Shi-Long  , Kong Hui  , Cen Cheng  , Su Jin-Rui  , Zhu Chang-Fei  ,   中国科学技术大学材料科学与工程系,先进功能材料与器件实验室，合肥  230026
Published: December 2020

Temperature dependence of longitudinal and transverse ultrasonic velocities and attenuations of the single-phase polycrystalline LaCoO3 were presente d. A clear softening in the longitudinal ultrasonic velocity accompanied by a sharp peak in attenuation were observed near the spin-state transition temperature(≈90K), which did not appear in the transverse mode measurement. This anomalous ultraso nic behavior further demonstrates that the spin-state transition of Co3+ ions in LaCoO3 near 90K are more likely from a low spin state (LS,t62ge 0g) to an intermediate spin state (IS,t5 2ge1g ) than to a high s pin state (HS,t42ge2g ). A b ig attenuation peak accompanied by a slight softening in velocity was observed near 200K in both longitudinal and tr ansverse modes, which was probably caused by the relaxation of the local distort ions originating from Jahn-Teller effect of the randomly distributed IS state Co 3+ ions.
M?ssbauer spectra study on phase variation in a high-coercivity FeCrCo alloy
Authors: Li Teng  , Li Wei  , Li Xiu-Mei  ,   钢铁研究总院功能材料研究所，北京  100081
Published: December 2020

Variation of the coercivity induced by increasing Cr and Co contents and adding inpurities of Mo and Zr in FeCrCo alloys was investigated using Mssbauer spec tra, fransmission electron microscopy, x-ray diffraction, and magnetic measureme nt. A coercivity as high as 76kA/m is obtained, which is one and half times high er than that (40—52kA/m) of the common alloy. Mssbauer spectra shows that the microstructure of the high-coercivity alloy is apparently different from that of the traditional FeCrCo alloy. The alloy is single-phase after solution treat ment, the non-magnetic γ　phase, which weakens the magnetic properties, does no t appear. During the thermomagnetic treatment, the atomic distribution is rearra nged, and leads to the formation of the α2 phase, the spinodal struc ture with the two-phase (α1 +α2 ) in the alloy fully forms after step-tempering. It might be beneficial for forming the high coercivity in alloy. Comparied with th e low-coercivity case, more of the α1 phase exist in the spinodal st ructure.
Determination of the optical constants of porous anodic aluminum oxide films
Authors: Wang Cheng-Wei  , Wang Jian  , Li Yan  , Liu Wei-Min  , Xu Tao  , Sun Xiao-Wei  , Li Hu-Lin  ,   (1)兰州大学化学化工学院，兰州  730000; (2)西北师范大学物理与电子工程学院，兰州  730070; (3)中国科学院兰州化学物理研究所固体润滑国家重点实验室，兰州  730000
Published: December 2020

A simple method was established based on the envelope curves of the optical transmission spectrum over the wavelength range of 200 to 2500 nm at normal inc idence, which was used for the accurate determination of the optical constants o f the anodic aluminum oxide(AAO) films. The results showed that the AAO films exhibited the optical features of a semiconductor with direct band gap of about 45 eV, and the optical constants of the AAO films depended strongly on the ano dic oxidation voltage, an important technologic parameter for preparation of AAO films. With the increase of the anodic oxidation voltage, the optical constants including the refractive index, thickness and optical band gap of AAO films inc reased, and the extinction coefficient decreased. Meanwhile, the fact that the c alculated values of the thickness of AAO films were in satisfactory agreement wi th the values of measurement illuminated that the results were well self_consist ent with the experiment.
Effect of microstructure on the mechanical properties of Fe45—50 Cr30—35Co20—25Mo0—4Zr0—2 alloy
Authors: Li Teng  , Li Wei  , Pan Wei  , Li Xiu-Mei  ,   钢铁研究总院功能材料研究所，北京  100081
Published: December 2020

In this paper,the relationship between the mechanical properties and the microstructure of a high-coercivity FeCrCo alloy was studied.Measurements on bending strength and fracture toughness showed that the mechanical properties of the high-coercivity FeCrCo alloy are much lower than the conventional FeCrCo alloy.TEM micrographs showed that the composition contrast between the two phases in the high-coercivity alloy is larger;XRD results indicated that the peak intensities of the high-coercivity alloy is lower and the half-peak-width is larger,which indicated that the spinodal decomposition processes are more successfully in the high-coercivity alloy.The enlargement of the composition contrast between α1 and α2 leads to the increase of crystal mismatch,the st rength of the alloy improved,but the ductility deteriorated,that is the reason why the mechanical properties of the high-coercivity alloy is poor.
Structures and dielectric properties of (Ba0.7Sr0.3)TiO3/LaNiO3 hetero-structure films prepared by sol-gel technique
Authors: Jia Jian-Feng  , Huang Kai  , Pan Qing-Tao  , He De-Yan  ,   兰州大学物理科学与技术学院,兰州  730000
Published: December 2020

(Ba0.7Sr0.3)TiO３/LaNiO３ he tero-structure films have been prepared on Si(100) substrate by an improved sol-gel technique. The structures and d ielectric properties for the films have been evaluated as a function of crystall ization temperature. It was found that LaNiO３ films show the lowest resistivi ty after annealing at 750 ℃ in flowing O２ for 30 min. C-V and I-V measureme nts revealed that the (Ba0.7Sr0.3)TiO３ films have excellent diele ctric properties. The dielectric constant of the (Ba0.7Sr0 .3)TiO３ film annealed at 750 ℃ is larger than 300 under the measuring conditions of 50 kHz, zero bias voltage and room temperature. The maximum leakage current dens ity of the hetero-structure is about 1.2×１０－６ A/cm２ under a bias voltage of 6 V.
Influence of annealing temperature on the luminescence of Er/Yb co-doped Al2O3 films
Authors: Tan Na  , Duan Shu-Qing  , Zhang Qing-Yu  ,   大连理工大学三束材料改性国家重点实验室, 大连  116024
Published: December 2020

The influence of annealing temperature on the photo-luminescence (PL) of high co ncentration Er/Yb co-doped Al２O３ films was studied. The relationship betwe en PL spectra and microstructure of the films at various annealing temperatures was revealed by analyzing the dependence of the intensity and the full width at half-maximum of the PL spectra on the annealing temperature. The PL measurement shows that the annealing behavior may be split into three different regimes. Bel ow 750℃, the intensity increases with the increase of annealing temperature wit h a small slope, which corresponds to the amorphous Al２O３ films. Between 800℃ and 900℃, the PL intensity increases considerably, where the microstructure of the films was identified to be composed of γ-Al２O３ grains in nano-meter scale; At the temperature of 1000℃, the intensity of PL spectrum decre ases to a very low level, γ-Al２O３ grains and the segreg ation of Er2O ３ and Yb2O３ phases were observed by using transmis sion electron microscopy . Furthermore, the dependence of PL spectrum shape on the PL intensity of sub-le vel transition was analyzed and discussed by fitting the PL spectra at various t emperatures．
Theoretical study of infrared emissivity of indium tin oxide films
Authors: Zhang Wei-Jia  , Wang Tian-Min  , Zhong Li-Zhi  , Wu Xiao-Wen  , Cui Min  ,   北京航空航天大学 理学院,北京  100083
Published: December 2020

Infrared emissivity of high quality indium tin oxide (ITO) film has been calcula ted based on the infrared radiation theory and thin film optical theory, the the oretical curves and the testing curves basically agree with each other. It is concluded that when the sheet resistance is less than 30Ω, the theoretical val ue of infrared emissivity of ITO films on the infrared wave band of 8μm to 14μ m will be less than 0.1. Therefore, the ITO film of practical sheet resistance less than 10Ω has good infrared stealthy capability. Physical mechanism of low infrared emissivity for ITO film is discussed, and the critical sheet resistance of low infrared emissivity, which conduce to the theoretical study and the ma nufacture of infrared stealthy ITO film, is put forward in this paper.
A study on the effect of Fraunhofer structure on the measurement of atmospheric pollutants with differential optical absorption spectroscopy
Authors: Zhou Bin  , Hao Nan  , Chen Li-Min  ,   复旦大学环境科学与工程系,上海  200433
Published: December 2020

During the measurment of atmospheric environment with differential optical absorption spectroscopy, stray light of the sun will be added to the measurment spectrum and the Fraunhofer structure in the solar radiation could affect the measurement of NO２, CH2O, HONO etc. But if it is treated as a k ind of `component' of atmosphere and retrieved with other atmospheric components together, its ef fect on the measurement could be restricted to a minimum.
Production and character of Al3O3N nanowires
Authors: Li Zhi-Jie  , Pan Xue-Ling  , Sun Wei-Min  , Qu Jia-Hui  , Wang Fu  ,   (1)东北大学材料与冶金学院，沈阳  110004; (2)东北大学材料与冶金学院，沈阳  110004;沈阳工业大学理学院，沈阳  110023; (3)辽宁大学物理系，沈阳  110036; (4)沈阳工业大学理学院，沈阳  110023
Published: December 2020

Al3O3N nanowires were successfully synthesized by dc arc_discharge in H2+Ar with a little amount of N2+O2 Composition, morphologies, microstructures were characterized using x_ray diffraction, scanning electron microscopy, Trans mission electron microscopy(TEM),and high resolution TEM. The synthesized Al3O 3N nanowires had the diameters ranging from 25 to 110 nm and the lengths up t o 55 μm. Al3O3N nanowires is of a spinel type structure. Besides, the growth mechanism of Al3O3N has also been studied.
Phase field modeling of directional solidification of a binary alloy at high velocities
Authors: Li Mei-E  , Yang Gen-Cang  , Zhou Yao-He  ,   (1)西安交通大学材料科学与工程学院,西安  710049; (2)西北工业大学凝固技术国家重点实验室，西安  710072
Published: December 2020

Some computational results on directional solidification of a binary alloy obtained by using the phase field model are reported. Frozen temperature approximatio n is adopted to simplify the modeling. The onset of morphological instability, t he pattern evolution and the solute redistribution are shown. The cell to planar interface transition is modeled near the high velocity absolute stability condi tion. The cell spacings, tip temperatures and solute partitioning coefficients a t different velocities are calculated. The solute trapping is also observed.
The structure and electronic state of the ordered thin film of perylene and tetracene on Ag(110) surface
Authors: Mao Hong-Ying  , Huang Han  , Yan Xin-Cheng  , Chen Qiao  , Qian Hui-Qin  , Zhang Jian-Hua  , Li Hai-Yang  , He Pi-Mo  , Bao Shi-Ning  ,   (1)圣安德鲁斯大学联合化学学院，英国; (2)浙江大学物理系，杭州  310027; (3)浙江大学物理系，杭州  310027;浙江教育学院，杭州  310012
Published: December 2020

The growth of perylene and tetracene on Ag (110) has been studied by the ultraviolet photoemission spectroscopy (UPS) and low-energy electron diffraction (LEED). The LEED results illustrate that an ordered C(6×2) structure can be observed when the thickness of perylene is about one monolayer (thickness of 03n m), and an ordered C (4×2) structure for tetracene with a thickness of one monolayer. From the measurements of UPS, four emission features of perylene are located at 35, 48, 64 and 85eV below the Fermi level respectively, and f our characteristic peaks, for tetracene, are located at 34, 49, 59 and 9 4 eV below the Fermi level. The angle_resolved ultraviolet photoemission spectro scopy measurements show that both perylene and tetracene near the interface are parallel to the substrate, the tetracene molecule is along ［110］ direction.
Analysis of 1991 March 24 CME’s structure using galactic cosmic rays’ data
Authors: Le Gui-Ming  , Han Yan-Ben  ,   (1)中国科学院国家天文台，北京  100012; (2)中国科学院国家天文台，北京  100012;中国科学院空间科学与应用研究中心，北京  100080
Published: December 2020

In this paper, 1991 March 24 CME's structure is analyzed by determining the moment of sudden change in galactic cosmic ray intensites using wavelet method based on the sudden change in galactic cosmic ray intensities when a CME just arrives at the magnetosphere. The results show that the thickness of the CME_driven sho ck is about 02228AU,while the space scale from the front side of the CME to th e most intense magnetic structure is about 0325AU.
Tow kinds of Mei symmeties and conserved quantities of a mechanical system in phase space
Authors: Fang Jian-Hui  , Liao Yong-Pan  , Peng Yong  ,   (1)河西学院物理系，张掖  734000; (2)石油大学(华东)物理科学与技术学院，东营  257061
Published: December 2020

Two kinds of Mei symmetries and conserved quantities of a mechanical system in phase space are studied. The definitions of the two kinds of Mei symmetries of me chanical system in phase space are given. The determining equations and conserve d quantities are obtained. An example is given to illustrate the application of the result.
The mechanism of dye-sensitized solar cell based on nanocrystalline ZnO films
Authors: Zeng Long-Yue  , Dai Song-Yuan  , Wang Kong-Jia  , Shi Cheng-Wu  , Kong Fan-Tai  , Hu Lin-Hua  , Pan Xu  ,   (1)中国科学院等离子体物理研究所，合肥  230031; (2)中国科学院等离子体物理研究所，合肥  230031;合肥工业大学,合肥  230009
Published: December 2020

This paper discusses the possibility of using nanocrystalline ZnO films as photo_electrode in dye_sensitized solar cells (DSCs). The performances and mechanism of DSCs based on ZnO nanoporous film are observed by using IR, UV_vis spectra and LSV method, and compared with dye_sensitized solar cells based on nanocrystalline TiO2 films. It is found that the low efficiency of DSCs based on ZnO is due to the poor binding force between the surface of nanocrystalline ZnO films and the RuL2(NCS)2(L=2,2′_bipydyl_4,4′_dicarboxylate) dye.
Study of Madelung constants of complex ionic crystals
Authors: Zhang Wei-Jia  , Wang Tian-Min  ,   北京航空航天大学理学院,北京  100083
Published: December 2020

A new formula together with the computing method for calculating Madelung constant α is given, based on the parallelepiped neutral cells which are situated around the reference cell,of which 26 such cells constitute the first shell and 98, 218,…,24 N2+2 cells constitute the second, third,…, and the Nth shell respec tively. The α(N) is a rapidly converging series and can be calculated very easily. In this paper Madelung constants and madelung energy for some complex io nic crystals have been computed by this new method which can be applied to all k inds of complex ionic crystals of trigonal ,orthorhombic system and so on.
The effects of H2O on the synthesis of SWCNTs by decomposing CH4 in Ar at 800℃
Authors: Ouyang Yu  , Fang Yan  ,   北京市纳米光电子学重点实验室，首都师范大学，北京  100037
Published: December 2020

The effects of H2O on the synthesis singlewall carbon nanotubes(SWCNTs)by decomposing CH4 in Ar at 800℃ were studied by TEM and Raman scattering. It is shown that the water existing in the reacting gas increases the percentage composition of the SWCNTs in the products. Preliminary analyses indicate that the water is involved in the purification course, and the generation of the amorphous carbon is brought about. Furthermore, the water can affect the distribution of the SWCNTs'diameter.
Study on the methods for diffraction-enhanced imaging with two crystals
Authors: Zhu Pei-Ping  , Wang Jun-Yue  , Yuan Qing-Xi  , Tian Yu-Lian  , Huang Wan-Xia  , Li Gang  , Hu Tian-Dou  , Jiang Xiao-Ming  , Wu Zi-Yu  ,   中国科学院高能物理研究所, 北京  100039
Published: December 2020

Diffraction_enhanced imaging by using two crystals has been recently developed i n x_ray topogrphy station in Beijing Synchrotron Radiation Facility. In this art icle the analysis for the influence of the thermal expansion of the first crysta l on the diffraction enhanced imaging is presented. The conclusion is that the i nfluence of the thermal expansion of the first crystal can be avoided and much b etter images can be obtained when the axes of crystals are placed vertically to the polarization plane of the synchrotron radiation. The experimental results co nfirmed this analysis.
Fast fabrication of large-area nanopore arrays by FIB
Authors: Chen Lei-Ming  , Li Pei-Gang  , Fu Xiu-Li  , Zhang Hai-Ying  , Li L. H.  , Tang Wei-Hua  ,   (1)Department of Physics,University of Rhode Island，Kingston，RI02881，USA; (2)中国科学院物理研究所，北京凝聚态物理国家实验室，北京  100080; (3)中国科学院物理研究所，北京凝聚态物理国家实验室，北京  100080;北京师范大学物理系，北京  100875
Published: December 2020

Fabrication of nanopore arrays is of great importance in nanodevices manufacture and basic scientific research. Focused ion beam (FIB) and electron beam lithography (EBL) have been widely used for fabrication of nanostructures.However, it takes very long time to fabricate nanostructure patterns of large area. In this p aper we report a novel fast fabrication method for nanopore arrays of large area by FIB. Each pixel of predesigned BMP file is regarded as a fabrication dot. B y matching the pixel of the presigned BMP pattern with the required fabrication area, nanopore arrays of large area can be fabricated in a very short time.
A Hartree-Fock-Slater-Boltzmann-Saha method for detailed atomic structure and equation of state of plasmas
Authors: Jiang Min-Hao  , Meng Xu-Jun  ,   应用物理与计算数学研究所，计算物理实验室，北京  100088
Published: December 2020

The effect of the free electron background in plasmas is introduced in HartreeFockSlater selfconsistent field atomic model to correct the single electron energies for each electron configuration, and to provide accurate atomic data for BoltzmannSaha equation. In the iteration process chemical potential is adjusted to change the free electron background to satisfy simultaneously the conservation of the free electrons in Saha equation as well as in HartreeFockSlater selfconsistent field atomic model. As examples the equations of state of the carbon and aluminum plasmas are calculated to show the applicability of this method.
Cluster-enhanced generation of multicharged xenon ions in nanosecond laser ionization of xenon beam
Authors: Luo Xiao-Lin  , Kong Xiang-Lei  , Niu Dong-Mei  , Qu Hong-Bo  , Li Hai-Yang  ,   (1)中国科学院安徽光学精密机械研究所,合肥  230031; (2)中国科学院安徽光学精密机械研究所,合肥  230031;中国科学院大连化学物理研究所,大连  116023
Published: December 2020

Multicharged xenon ions with charge up to 20 have been observed in laser ionization of xenon beam by a 25ns Nd:YAG 1064nm laser with a laser intensity of 1011—1012 W·cm-2 Experimental results indicate that the multicharged ions appeared only when the laser interacted with the middle part of the pulsed beam, and its intensity increases with the increase of the backing pressure of Xe source gas. These indicate that the clusters in the beam is essential to the production of multicharged ions. We also discuss the possible mechanism of the generation of the multicharged ions.
The energy levels structure and fluorescence properties of Ce3+ in LaAlO3 single crystals
Authors: Zeng Xiong-Hui  , Zhao Guang-Jun  , Zhang Lian-Han  , He Xiao-Ming  , Hang-Yin  , Li Hong-Jun  , Xu Jun  ,   (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  100039
Published: December 2020

LaAlO3 and Ce: LaAlO3 single crystals were grown by the Czochralski technique. Infrared absorption spectrum, ultraviolet absorption spectra, and fluorescence spectra were measured at room temperature. According to the absorption spectra, the energy levels structure of Ce3+ in LaAlO3 single crystals was confirmed. The fluorescence spectra of Ce: LaAlO3 were explained using this structure.
Study of interactions between DNA and histone with molecular combing method
Authors: Liu Yu-Ying  , Dou Shuo-Xing  , Wang Peng-Ye  , Xie Ping  , Wang Wei-Chi  ,   中国科学院物理研究所软物质物理实验室,北京  100080
Published: December 2020

The interactions between DNA and histone are studied by using the molecular combing method. With this simple but effective method, λDNA molecules are stretched to a length of 26—28 μm, 16—17 times of their contour length (～162 μm). After DNA binding of histones, DNA molecules are condensed and the lengths of the stretched complexes become significantly shorter, with length distribution peak lying between 10—14 μm. The lengths of the stretched DNAhistone complexes are closely related to the histone concentration and the mixing ratio of DNA base pair and dye molecule.
Study on the radiation characteristics of the dielectric parallelly loaded dipole antenna for pulse radiation
Authors: Han Zeng-Fu  , Wang Jun-Hong  ,   北京交通大学光波技术研究所,北京交通大学全光网络与现代通信网教育部重点实验室,北京  100044
Published: December 2020

The timedomain radiation characteristics of the resistanceloaded dipole ante nna with dielectric block parallelly connected to one side of the feeding region are studied by using finite difference time_domain(FDTD) method and perfectly m atched layer(PML) technique. It is found that this kind of antenna has very well directive property. The influences of the size and dielectric constant of the l oaded dielectric block on the radiation characteristics of the antenna are analy zed. The optimum structure parameters of antennas with very well directivity and enough efficiency are given. The low profile property of this kind of antenna m akes it easier to integrate with circuit. It is preferable for the ultrawide b and wireless communication system, such as UWB system, to use this kind of anten na.
Reconstruction of transverse permittivity and conductivity for a lossy anisotropic plate
Authors: Wei Bing  , Ge De-Biao  ,   西安电子科技大学理学院,西安  710071
Published: December 2020

Using the finite difference time domain (FDTD) method, the scattering of a lossy anisotropic plate is analyzed when the plate is illuminated by a plane transient electromagnetic wave. Based on the resonance characteristics of the back scattering RCS in frequency domain and the transient waveform of the back scattered electric field in time domain, a reconstruction scheme for recovering the transverse permittivity and conductivity for an anisotropic plate is proposed. The calculation results exemplify the availability and simplicity of the present scheme.
Dynamic characteristics of electrons in high-order corrected fields of ultrashort laser pulses
Authors: Hua Jian-Fei  , Huo Yu-Kun  , Lin Yu-Zheng  , Chen Zhao  , Xie Yong-Jie  , Zhang Shao-Yin  , Yan Zheng  , Xu Jun-Jie  ,   (1)复旦大学现代物理研究所,上海  200433; (2)清华大学工程物理系,北京  100084
Published: December 2020

Highorder correction to the fields of ultrashort, tightlyfocused laser pulses expressed in power series of ε=1/(ω0t0) and s=1/(k0w0)（ω0=ck0 the central oscillatory frequency, t0 the pulse duration, w0 the beam waist radius), are derived. Based on paraxial approximation, the firstorder correction terms to the Gaussian pulses are explicitly given. Their corrections of amplitude and phase, are found to be related to the variable of ε. Applying them to the study of the electron dynamics in the intense laser pulse field, we found that as long as ω0t0>20, the zerothorder approximation (long pulse approximation) is adequate for describing the interaction. For ω0t0<20, higherorder corrections have to be taken into account.
Diffraction-enhanced imaging experiments in BSRF
Authors: Huang Wan-Xia  , Yuan Qing-Xi  , Tian Yu-Lian  , Zhu Pei-Ping  , Jiang Xiao-Ming  , Wang Jun-Yue  ,   中国科学院高能物理研究所,北京  100039
Published: December 2020

A new x_ray imaging technique, diffraction_enhanced imaging, has been recently developed in Beijing Synchrotron Radiation Facility(BSRF). Diffraction_enhanced i maging is a radiographic technique that derives contrast from an object’s absor ption, refraction gradient and small_angle scatter properties(extinction). This imaging method may improve image quality for medical applications, industrial ra diography for non_destructive testing and x_ray computed tomography.
Dynamical properties in the system of two identical two-level entangled atoms interacting with radiation fields in binomial states
Authors: Song Jun  , Cao Zhuo-Liang  ,   (1)安徽大学物理系,合肥  230026; (2)皖西学院物理系,六安  237012;安徽大学物理系,合肥  230026
Published: December 2020

In this article, the dynamical properties in the system of two identical twolevel entangled atoms interacting with a binomial optical field are studied by means of time evolution operator and numerical calculations. The results show that the time evolution of atomic population and atomic dipole squeezing depends on the degree of entanglement of the initial two identical twolevel entangled atoms and the parameters of the binomial state optical field. The atomic dipole moment can be completely squeezed via choosing appropriate parameters of the system.
An average-atom model with potential-well and mixed form of exchange potential
Authors: Jia Hong-Xiang  , Meng Xu-Jun  ,   北京应用物理与计算数学研究所计算物理实验室，北京  100088
Published: December 2020

A traditional average-atom model (AAM) is improved in several aspects. 1. A dynamic criterion for free electrons is adopted. 2. The free electrons are classifie d in three types, each of which is treated by the partial wave method and Fermi- Dirac statistics. 3. An exchange potential in mixed type is obtained to replace the Slater potential by applying the variation principle. 4. A parameter α in t he atomic structure is calibrated by the constants of material under normal cond itions. As examples electron pressures of Iron, Nickel and Copper at zero temper ature are calculated and compared with the results obtained by other theories an d in experiments.
Quantum mechanical channel and quantum mutual entropy in the two-photon Jaynes-Cummings model with atomic motion
Authors: Liu Xiao-Juan  , Fang Mao-Fa  , Zhou Qing-Ping  ,   (1)湖南师范大学物理与信息学院,长沙  410081;中国科学院安徽光学精密机械研究所,合肥  230031; (2)湖南师范大学物理与信息学院,长沙  410081;中国科学院安徽光学精密机械研究所,合肥  230031;湖南科技大学物理学院,湘潭  411201
Published: December 2020

The dynamics of the two_photon Jaynes_Cummings model with atomic motion are studied by using the quantum information theory, and the quantum echanical channel representing the state change of atom is given; the quantum mutual entropy and reduced entropy of the atom are derived. The influences of the atomic motion and the field structure on the quantum mutual entropy are examined. It is shown that the properties of quantum mechanical channel are strongly dependent on the atomic motion, the field model structure, and the entanglement between the atom and the field.
Study of small-scale self-focusing in laser beams by high-order contrast
Authors: Yi Xu-Nong  , Hu Wei  , Luo Hai-Lu  , Zhu Jing  ,   华南师范大学传输光学实验室，广州  510631
Published: December 2020

In this paper, high_order contrast is brought forward for studying small_scale self_focusing phenomenon in high_power solid state laser drivers. Based on the properties of semi_invariant, we obtain the analytic expressions of high_order contrast of near field of beams. Finally, we study the propagation of plane waves with PSD phase noise and obtain the evolution of fill factor, modulation, contra st, third_order contrast and fourth_order contrast with Bintegral value. C omparing the results of numerical simulation, we find that third_order contrast and fourth_order contrast are good parameters for characterizing the small_scale self_focusing phenomenon.
Compensation of group velocity mismatching of three pulses in femtosecond optical parametric amplification
Authors: Ma Jing  , Zhang Ruo-Bing  , Zhang Wei-Li  , Wang Qing-Yue  ,   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（天津大学），天津  300072
Published: December 2020

For avoiding adverse effect arising from group velocity mismatching in parametri c amplification, a new method is presented, in which we combine pulse front slan t and noncollinear phase matching to completely compensate group velocity mismat ching of three pulses, in femtosecond optical parametric amplification (OPA). Th e change of the phase matching angle, the pulse front slant angle and the noncol linear angle with the signal wavelength are calculated, when group velocity matc hing of three pulses is achieved in BBO crystal type_Ⅰ and typeⅡ phase matching configurations. The effect of group velocity matching of three pulses on the spatial walk_off length, the parametric gain and the parametric bandwidth is analyzed. The results indicate that, using this method can make matching of gro up velocities of three pulses, when tuned continuously in both BBO type_I and Ⅱ phase matching femtosecond OPA, and thus the effective interaction length of th ree pulses is increased considerably. This calculation method and the analysis r esults provided a theoretical guidance for obtaining parametric pulses with high er gain and shorter duration.
Design of polarization band-pass filters based on the theory of thin-film photonic crystal superlattice
Authors: Gu Pei-Fu  , Chen Hai-Xing  , Qin Xiao-Yun  , Liu Xu  ,   浙江大学现代光学仪器国家重点实验室,杭州  310027
Published: December 2020

The principle of design of polarization band_pass filters used for wavelength d ivision multiplexing systems is presented. The design method is based on the con cept of thin_film photonic crystal superlattice. Two kinds of design are put for ward. One of them is to construct by superposition of two photonic crystals; and the other is to insert a new photonic crystal into the middle of a photonic cr ystal, so that there are in effect three photonic crystals. Such band_pass filte rs have excellent optical properties with p_polarization transmittance and s_pol arization reflectance. The characteristics of the filters, including peak transm ittance, half_band width and rejection are discussed.
Mutual compensation of higher-order dispersion in chirped pulse amplifier with a Martinez stretcher
Authors: Sun Zhen-Hong  , Chai Lu  , Zhang Zhi-Gang  , Wang Qing-Yue  , Zhang Wei-Li  , Yuan Xiao-Dong  , Huang Xiao-Jun  ,   (1)天津大学精密仪器与光电子工程学院超快激光研究室，国家教育部光电子信息技术科学重点实验室,天津  300072; (2)天津大学精密仪器与光电子工程学院超快激光研究室，国家教育部光电子信息技术科学重点实验室,天津  300072;俄克拉荷马州立大学电气与计算机工程系，斯帝尔沃特，OK  74078; (3)天津大学精密仪器与光电子工程学院超快激光研究室，国家教育部光电子信息技术科学重点实验室,天津  300072;中国工程物理研究院激光聚变研究中心，绵阳  621900; (4)中国工程物理研究院激光聚变研究中心，绵阳  621900
Published: December 2020

The dispersion in a chirped pulse amplifier (CPA) with a Martinez stretcher is analyzed theoretically based on ray_tracing. The method of mutual compensation th at introduced properly the negative third_order dispersion to balance the fifth_ order dispersion is presented. A shorter pulse near the transform_limit can be g enerated by this method rather than by the traditional approach that zeros the s econd and the third order dispersion successively in the CPA system.
The effect of channel width on the distribution of two-dimensional granular flow in an inclined channel
Authors: Bao De-Song  , Zhou Ying  , Zhang Xun-Sheng  , Tang Xiao-Wei  ,   浙江大学物理系，杭州  310027
Published: December 2020

We have investigated the distribution of two_dimensional granular flow in inclin ed channel and the distribution of the density of granular flux (ξ=ρ·ν) near the rough boundary walls. The results showed that the transverse distributi on of the density of granular flux is symmetric about the channel center, and th ere exists a strong extremum near the wall; the distribution of the density of g ranular flux near the walls is nonlinear with increasing inclination. In this paper, we turn attention to the effect of channel width on the distribution of the density of granular flux. There is a critical channel width for the distribu tion of the density of granular flux. In our experimental condition, the critica l width is 700mm (Wc=70d,d being the granular diameter), and there i s a weak extremum in the curve of the density of granular flux distribution when the channel width is in the range from 70 to 80d. When the channel width is smaller than the critical width, the density of granular flux can be expressed by ξ∝(sinθ)α with,032≤α≤085 the value of α is related with the channel width.
Study on the preparation of high barrier hydrogenated carbon film and its properties
Authors: Chen Guang-Liang  , Ge Yuan-Jing  , Zhang Yue-Fei  , Zhang Guang-Qiu  , Zhang Gu-Ling  , Wang Jiu-Li  , Liu Yuan-Fu  , Gu Wei-Chao  , Feng Wen-Ran  , Liu Chi-Zi  , Yang Si-Ze  ,   (1)等离子体物理及材料实验室，北京印刷学院，北京  102600; (2)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;等离子体物理及材料实验室，北京印刷学院，北京  102600
Published: December 2020

Hydrogenated carbon thin films were fabricated on the surface of polyethylene terepthalate(PET) by radio frequency plasma enhanced chemical vapor deposition (r. f.PECVD).The film structure properties were studied by means of atomic force mic roscope(AFM), x_ray photo_electron (XPS), laser Raman spectroscopy, Fourier_tra nsform infrared spectra(FTIR),etc. The barrier property of the film was conducte d on the water vapor permeation instrument. The results show that nano_hydrogen ated carbon films have been deposited on PET surface and they are mainly compose d of sp2 and sp3 hybridized hydrogenated carbon compounds. Plasma pa rameters influence the films' growth rate and structure characteristics. The fil m reduces the water vapor permeation ratio of the PET by 7 times at a film thick ness of only 900nm.
The manipulation of Cu subsurface interstitial atoms with scanning tunneling microscope
Authors: Ge Si-Ping  , Zhu Xing  , Yang Wei-Sheng  ,   北京大学物理学院人工微结构与介观物理国家重点实验室,北京  100871
Published: December 2020

In this paper, the Cu(001) surface covered with glycylglycine has been studied by scanning tunneling microscope(STM) under ultra_high vacuum condition. On that surface copper clusters in nanometer_scale, which could form alphabet or graph a t our wishes, may be produced by the scanning of STM under a certain bias voltag e condition. The height of these clusters has a close relation with bias voltage , tunnel current and time. It offers the opportunity to fabricate nanometer_scal e apparatus by these clusters due to their stability at room temperature. The ex perimental result shows that the copper atoms which form these clusters come fro m neither copper substrate surface nor STM tip. We think that the tensile stress field in the copper substrate is produced due to the chemisorbed glycylglycine molecule in tunnel electric field and it is the migration of copper subsurface i nterstitial atoms under that tensile stress field that causes the formation of c opper clusters.
The magnetism of Sm1－xGdxAl2 at low temperatures
Authors: Wu Zi-Hua  , Luo Jian-Lin  , Chen Zhao-Jia  , Liu Guang-Tong  , Wang Nan-Lin  , Wang Ke-Qin  , Wang Wan-Lu  ,   (1)中国科学技术大学理学院，合肥   230026; (2)中国科学院物理研究所，北京   100080; (3)重庆大学数理学院应用物理系，重庆   400044; (4)重庆大学数理学院应用物理系，重庆   400044;中国科学院物理研究所，北京   100080
Published: December 2020

The resistance and magnetic susceptibility of Sm1-xGdxAl2 with x=00098, 0019 and 003 have been studied at low temperatures. Spin moments and orbital moments couple antiparallelly in this material. The compensat ion temperature at which the spin moments are equal to orbital ones is observed, and it decreases with increasing x. The spin_orbit flip has been found in a strong field.
Study on surface modification of polytetrafluoroethylene by N+ ion implantation
Authors: Man Bao-Yuan  , Zhang Yun-Hai  , Lü Guo-Hua  , Liu Ai-Hua  , Zhang Qing-Gang  , Guzman L.  , Adami M.  , Miotello A.  ,   (1)Department of Physics，University of Trento，38050，Trento，Italy; (2)山东师范大学物理与电子科学学院，济南  250014
Published: December 2020

The polytetra_fluoroethylene (PTFE) substrates were implanted with 160 kev N ions to a dose range between 1×１0１4 and １×１017 ions/cm2 at di fferent temperatures. The treated samples were examined by visible (5145 nm) a nd Fourier transform infrared (1064 nm) Raman spectroscopy as well as by scannin g electron microscopy. Ion implantation on PTFE in the low dose range leads to e nhancement of crystallinity of PTFE. In the intermediate dose range, sputter los s effects are dominant and the roughness of the surface increases. At higher dos es, the microstructure strongly evolves and double CC bonds are created. In addi tion, the etching yield and the changing extent of the surface microstructure ar e enhanced by the temperature of PTFE substrate.
Effect on optical band-gap of transparent and conductive CdIn2O4 thin film due to defects-induced burstein-moss and band-gap narrowing characteristics
Authors: San Hai-Sheng  , Li Bin  , Feng Bo-Xue  , He Yu-Yang  , Chen Chong  ,   (1)兰州大学教育部磁学与磁性材料重点实验室，兰州  730000; (2)中国科学院上海技术物理研究所，上海  200083
Published: December 2020

Transparent and conductive oxides CdIn2O4 (CIO) thin films were prepared by RF reactive sputtering from a CdIn alloy target in Ar+O2 atmosphere. By the analysis and measurements of transmittance spectra and Hall_effect of different samples prepared at different substrate temperatures and post_deposition annealing in an Ar gas flow, it was found that the carrier density increases with the d ecrease of substrate temperature, but the absorption edge shows an abrupt change from a blue_shift to a red_shift. Theoretically, the paper formulated the effec t on band structure due to higher density of point defects, it embodies the band _tailing, Burstein_Moss (B_M) shift and band_gap narrowing. In addition,density of ionized impurity substrate temperature induced will affect the carrier mobili ty.The hole density impurity_induced will influences the magnitude of optical ba nd_gap and transmittance of light. Since extrapolation method does not fit degen erate materials, a more accurate method of obtaining band_gap is the method of c urve fitting.
The influence of the layer-to-layer interaction energy on the electronic energy in HgS/CdS/HgS columnar nanometer system
Authors: Zheng Rui-Lun  , Zhang Cui-Ling  , Chen Zhi-Qian  ,   (1)西南师范大学材料科学与材料工程学院,重庆  400715; (2)西南师范大学物理学院，重庆  400715
Published: December 2020

The variation of the electronic energy in a columnar nanometer system with the i ncrease of radius is established, and the HgS/CdS/HgS nanometer system is used to discuss the influence of the layer_to_layer interaction energy on the electr onic energy spectrum of electrons. Some important results indicate that the ene rgy of the electronic energy increases with the increase of the potential barrie r width and the wave vector, while the potential well width and the layer_to_la yer interaction energy makes the electronic energy larger, but it doesn't effec t the variation of electronic energy with the potential well width, potential ba rrier or the wave vector.
Characterization and bonding configuration of SiCOH low-k films
Authors: Wang Ting-Ting  , Ye Chao  , Ning Zhao-Yuan  , Cheng Shan-Hua  ,   苏州大学物理科学与技术学院薄膜材料江苏省重点实验室，苏州  215006
Published: December 2020

Using decamethylcyclopentasioxane (［Si(CH3)2O］5 as liquid precursor, SiCOH films, which have low dielectric constant (low k), good insulating ability and thermal stability, were prepared by electron cyclotron resonance chemical vapor deposition (ECR_CVD). The FTIR spectra of the films were measured to find the difference of bond structures between SiCOH films and DM5 source. It was verified that the Si—O—Si cyclic structure was retained in SiCOH films,while _CH3 radicals were lost during the deposition. The dielectric con stant decreased from 385 to 285 after the film was annealed in 400℃. With t he analysis of the bond structure of the film as deposited and annealed, we can infer that the increased content of cage structure comprised of Si—O—Si bond w ith bigger bond angle may be the reason for decreased dielectric constant.
An analytical model of MOSFET threshold voltage with considiring the quantum effects
Authors: Dai Yue-Hua  , Chen Jun-Ning  , Ke Dao-Ming  , Sun Jia-E  ,   安徽大学电子科学与技术学院,合肥  230039
Published: December 2020

Based on the improved approximation of modified triangular potential well, a phy sical_based model of MOSFETs threshold voltage is presented, as well as its anal ytical formulation. The new model takes quantum effects into account for future generation MOS devices and integration circuits. The calculated results by using the new model agree with the simulation results very well.
The influence of Sm doping at A site on the magnetic,electrical properties in La0.67Sr0.33MnO3
Authors: Liu Ning  , Xu Su-Jun  , Guo Huan-Yin  , Tong Wei  , Zhang Yu-Heng  ,   (1)宿州学院物理系，宿州  234000; (2)宿州学院物理系，宿州  234000;中国科学技术大学结构分析开放实验室，合肥  230026; (3)中国科学技术大学结构分析开放实验室，合肥  230026
Published: December 2020

In this paper, the M_T curves, ESR, Infrared and Raman spectra, ρ_T cu rves and MR_T curves of La067-xSmxSr033MnO 3 (x=000, 010, 020, 030) are studied. The experimental results ind icate that with increasing Sm content, the compound undergoes a transition from long_range ferromagnetic order to the cluster_spin glass state, and further to a ntiferromagnetic order. The variation in magnetic structure and extra magnetic c oupling caused by Sm doping lead to colossal magnetoresistance effect.
A model of ferroelectric capacitors based on hysteresis loop
Authors: Wang Long-Hai  , Yu Jun  , Wang Yun-Bo  , Peng Gang  , Liu Feng  , Gao Jun-Xiong  ,   华中科技大学电子科学与技术系,武汉  430074
Published: December 2020

Based on the characteristic of ferroelectric microstructure, a crystal cell of ferroelectric is regarded as a dipole. Analysis of the switching property of di pole in the electric filed is made. According to the statistic principle, differ ent distribution functions are used to fit the probability of dipole switching. A model based on hysteresis loop is developed. Experimental data on PZT show go od agreement with the model for various loops, and the model is easily linked to simulative software of circuit for either memory or analog design application.
Investigation of photon geometric phases inside a curved fiber made of biaxially anisotropic left-handed media
Authors: Zhuang Fei  , Shen Jian-Qi  ,   (1)杭州师范学院理学院凝聚态物理研究所,杭州  310012; (2)浙江大学（玉泉校区）物理系，浙江近代物理中心,杭州  310027;浙江大学（玉泉校区）光及电磁波研究中心，杭州  310027
Published: December 2020

The novel optical properties of wave propagation and the special feature of phot on geometric phases inside a noncoplanarly curved fiber made of biaxially anisot ropic left_handed media are considered in this paper. In general, the photon geo metric phases is inevitably dependent on the solid angle subtended by the curve along which the photon moves, which presents the topological and global property of time evolution of photon wavefunctions. It is, however, shown that inside a biaxially anisotropic left_handed fiber the photon geometric phases will be inde pendent of the cone angle, since the contributions of negative and positive refr active indices to the geometric phases of circularly polarized photons have been cancelled each other. In addition, we discuss briefly the properties of the qua ntum_vacuum geometric phases resulting from the quantum vacuum fluctuation, and the probability of the detection of such a vacuum effect in experiments.
The homotopic solving method for a class of El Ni?o sea-air oscillator mechanism
Authors: Mo Jia-Qi  , Lin Wan-Tao  ,   (1)安徽师范大学数学系,芜湖241000; (2)中国科学院大气物理研究所,北京100029
Published: December 2020

A class of coupled systems in oscillation of the El Nio-Southern Oscillation (ENSO) mechanism has been studied. Using the homotopic mapping and perturbed theory, approximate expansions of the solution for a class of ENSO model are obtained in a simple manner.
Solution of the nonlinear Schr?dinger equation using the generalized Lie group reduction method
Authors: Ruan Hang-Yu  , Li Hui-Jun  ,   宁波大学物理系,宁波315211
Published: December 2020

In this paper, by using the technique of generalized Lie group reduction, the exact solutions of the nonlinear Schrdinger equation with distributed dispersion, nonlinearity, and gain (or loss) are obtained. And, the potential application of the general solitary wave solutions and the chirped solitary wave solutions in optical fibers communication and optical fibers amplifiers have also been studied thoroughly. This will provide the possibility in making new optical fibers amplifiers.
General multi-linear variable separation approach to solving low dimensional nonlinear systems and localized exitations
Authors: Shen Shou-Feng  ,   浙江工业大学数学系，杭州  310014
Published: December 2020

Multi-linear variable separation approach based on the corresponding Bcklund transformation (BT-MLVSA) is a useful method to solve nonlinear systems. General multi-linear variable separation approach (GMLVSA) is its extension and there are four ways to realize it. The first one is to expand the nonlinear systems according to multi-arbitrary functions, the second one is to expand the variable separation ansatz. The third one is the MLVSA based on the Darboux transformation (DT-MLVSA) and the last one is the derivative-dependent functional variable separation method. By using the first kind of GMLVSA, the solutions can be obtained for the (2+1)-dimensional mNNV system and sine-Gordon system. In this paper, the first kind of GMLVSA is extended to solve some two-dimensional nonlinear systems which are derived from the (2+1)-dimensional sine-Gordon system by using symmetry reduction method. Namely, the applicability of the method is retained from high dimensional systems to low dimensional systems in the symmery reduction sense. This also provide a way of deducing low dimensional systems which can be solved by GMLVSA from high dimensional systems.