bluuebunny/crossref_metadata_2025 huggingface dataset:
TUNABLE-SAMPLING-DEPTH ELECTRON ENERGY LOSS SPECTROSCOPY AND AUGER ELECTRON SPECTROSC-OPY STUDIES OF Pb/Ni(001) INTERFACE
Authors: ZHAO RU-GUANG  , YANG WEI-SHENG  ,   北京大学物理系,北京100871
Published: November 2020

We have studied the interface formation process of Pb/Ni (001) system by means of tunable-sampling-depth electron energy loss spectroscopy (TELS) and Auger electron spectroscopy (AES). During the deposition of Pb, the AES peak height ratio of Pb to Ni versus time of deposition consists of three segments with the two turning points corresponding to 1 mono-layer (ML) and 2 ML respectively, indicating the Franck-Van der Merwe, i.e. layer by layer growth mode. Also during the Pb deposition, the Pb 6s band ELS peak appears as the Pb coverage is beyond 1 ML, while the Pb bulk plasmon peak appears at about 2 ML of Pb coverage. During the whole process of deposition and annealing, the ELS peak position and width of the Pb bulk plasmon peak, the 6s band peak as well as the Ni 3p band peak maintain their own pure metal values, and there was no new bulk plasmon peak. In view of all these facts, we have reached the conclusion that there is no intermixing of Pb with Ni and the interface of this system is abrupt.
SUPERCONDUCTIVITY OF RICH-Ca,Cu Bi(Pb)-Sr- Ca-Cu-O SYSTEM
Authors: LU YA-FENG  , WU XIAO-ZU  , LI QING-YUN  , ZHOU LIAN  , XIN MIAN-RONG  , LUO CHANG-XUN  ,   (1)陕西师范大学物理系,西安710062; (2)西北有色金属研究院,宝鸡721014; (3)西北有色金属研究院,宝鸡721014;陕西师范大学物理系,西安710062
Published: November 2020

The superconductors with nominal composition of Bi2.0-xPbxSr1.9Ca2.2Cu3.3Oy were prepared by solid-state reaction method, XRD patterns were systematically studied for the samples. The results indicated that rich-Ca, Cu could accelerate the formation of (2223) phase, and broaden the sintering temperature range for a single phase. High-quality polycrystalline sample of 110K single phase was obtained. Annealing at lower temperature is beneficial to increase the volume ratio of 110K phase.
A THEORETICAL STUDY OF RAMAN SOLITON-LIKE PULSES IN SINGLE-MODE FIBERS
Authors: LI YING-XING  , LI SHI-CHEN  , HUANG CHAO  , YU JIAN  ,   (1)天津大学精密仪器工程系,天津300072; (2)天津大学精密仪器工程系,天津300072;天津医学院生物医学工程系,天津300070
Published: November 2020

We present a unique theoretical model to describe the Raman soliton-like pulses in single-mode fibers and consider the existence of the group velocity dispersion (GVD), the stimulated Raman scattering (SRS), the self-phase modulation (SPM), the cross-phase modulation (XPM) and the fiber loss. The experiment made by Gouveianeto et al. is simulated and 84fs Raman soliton-like pulses are obtained in agreement with the experimental results. A distinct image of the evolution of Raman soliton-like pulses is abtained and some new ideas are put forward.
QUAS1-THERMODYNAMIC MODEL OF THE DISSIPATIVE SYSTEMS AND ITS APPLICATION TO PHASE TRANSITIONS IN OPTICAL BISTABILITY
Authors: OU FA  ,   华南理工大学应用物理系,广州510641
Published: November 2020

Taking the optical system as a prototype, this paper demonstrates that a quasi-thermodynamic model for dissipative systems, satisfying the principle of detailed balance, may be developed, which is parallel to the traditional thermodynamics. The present systems are described by the generalized dynamical equation of nonlinear optical cavities, introduced in previous work of Ou Fa et al. In view of the quasi-thermodynamic model, the critical phenomena and phase transitions in optical bistability are discussed systematically and generally. By taking the advantage of Ginzburg-Landau's model, the fluctuations and correlations near the (second kind of) critical point of optical bistability are studied also. So the Landau's theory of phase transitions in equilibrium thermodynamics is generalized to the bistable dissipative systems far from equilibrium.
SQUEEZING EFFECT FOR OFF-RESONANT TWO-PHOTON LASER WITH AN INJECTED SIGNAL IN GOOD- CAVITY CASE
Authors: S. SACHULF  , HU GANG  , YANG GUO-JIAN  ,   (1)北京师范大学低能核物理研究所,北京100875; (2)北京师范大学物理系,北京100875
Published: November 2020

The field squeezing effect for off-resonant two-photon laser with an injected signal in good-cavity limit is studied by means of Fokker-Planck equation of the peneralized Wigner distribution. Under certain off-resonance condition, the field squeezing effect of two-photon laser may be observed.
ANOMALOUS DISLOCATION INTERNAL FRICTION IN HIGH PURITY ALUMINIUM
Authors: TAN QI  ,   中国科学技术大学内耗与固体缺陷联合开放研究实验室,合肥230026
Published: November 2020

The behavior of internal friction during strain ageing and amplitude-dependent effect behaved in high purity aluminium were studied. After specimen is twisted to a certain degree, internal friction exhibits anomalously amplitude dependent effect. This can be observed in a large temperature region but does not appear in completely annealed or elongated specimens. The way of twisting deformation of specimen can affect amplitude-dependent effect. As the purity is lower, the anomalously amplitude-dependent effect is not so easy to be observed. It is considered that the appearance of anomalously amplitude-dependent effect is attributed to the reason that deformation leads to high enough dislocation density and much smaller region allowed for the movement of dislocations. The increase of nternal friction during strain ageing at room temperature is suggested to be due to the dislocation slip aided by vacancy produced through deformation.
NUCLEATiON AGGREGATION MODEL OF FRACTAL GROWTH OF MOLYBDENUM OXIDE
Authors: ZHANG JI-ZHONG  ,   清华大学材料科学与工程系,北京100084;中国高等科学技术中心世界实验室北京100080
Published: November 2020

Tre vapor-solid phase transition of the motybdenum oxide was investigated in the stochastic nonlinear system which was in far from equilibrium state. Some thin molybdena crystals and various two-dimensional fractal structures consisted of the molybdena whiskers were ob-served. The possible mechanism of the fractal structures is discussed in terms of nonequilibrium thermodynamics of irreversible processes and a nucleation aggregation model is proposed.
A STUDY ON THE GAIN COEFFICIENT OF TWO WAVE COUPLING IN DOPED KNSBN CRYSTALS
Authors: ZHU DE-RUI  , WANG REN  , TAN JIAN-HUA  , MO DANG  ,   中山大学物理系,广州510275
Published: November 2020

Two wave coupling experiments of doped KNSBN single crystals have been performed. The gain coefficient of two wave coupling Γ as a function of the crossing angle of the beam 2θ, and Γ as a function of the intensity of light / in various samples were measured. The effective photo-refractive charge density, the effective electro-optic coefficient and the hole-electron competition factor have been determined by model fitting. The analytical expression of the intensity-dependent gain coefficient is deduced. We use this expression to analyse the experiment data of Γ-I. Our result shows that high values of Γ(>15 cm-1) exist in some kinds of doped KNSBN crystals.
VARIATIONAL STUDY FOR A COUPLED SYSTEM OF A QUANTUM TUNNELING STATE WITH PHONONS
Authors: SHI YUN-LONG  , NIE YI-HANG  , CHEN HONG  , WU XIANG  ,   (1)同济大学物理系,上海200092; (2)雁北师范学院物理系,大同037000
Published: November 2020

The ground state energy of a coupled system of a quantum tunneling state with phonons is investegated by a variational approach. We find that the ground state of the system may be described by two variation states-displaced state and displaced-squeezed state, and the transition of the stable ground state from displaced state to displaced-squeezed state will occur as coupling strength increases. The phase diagram of the transition is also given.
INFLUENCE OF HALOGEN FAMILY ANIONS ON SERS SIGNAL IN Ag SURFACE-MOLECULE SYSTEM
Authors: MIAO RUN-CAI  , PAN DUO-HAI  , CHEN FA-TANG  , ZHANG XIN-HUI  ,   陕西师范大学物理系,西安710062
Published: November 2020

The influence of halogen family elements on the SERS signal was studied. The relation-shap between the SERS intensity and the concentration of halide and reversal phenomena of intensity of Raman peaks were discovered. Finally, some explanations were givea.
SPUTTERING RESEARCH OF Al-50wt％Sn ALLOY
Authors: WANG ZHEN-XIA  , ZHANG JI-PING  , PAN JI-SHENG  , TAO ZHEN-LAN  , ZHANG HUI-MING  , ZHAO LIE  , ZENG YUE-WU  , WANG CHENG-BAO  , LIN ZHEN-CHANG  ,   (1)杭州大学中心实验室,杭州310028; (2)上海合金厂,上海201800; (3)中国科学院上海原子核研究所,上海201800
Published: November 2020

The angular distributions of sputtered Al and Sn atoms ejected from the Al-Sn multi phase alloy bombarded by 30keV Ar+ ion have been measured with collector technique and RBS analysis. The sputtered surface has been observed with scanning electron microscopy (SEM), and its compositions have been analyzed both in sputtered and unsputtered areas with electron x-ray probe microanalyser (EPMA). The results show that the angular distribution of sputtered Al atoms is nearly cosine, and that of Sn is over-cosine. To explain the experimental results we propose a reasonablt sputtering yield equation, Y(θ) = ∑Yi(θ) each , Yi(θ) stands for the sputtering yield of the area in which its surface topography and compositions is different from other areas.
INFLUENCE OF HYDROGEN AND TEMPERATURE ON POSITRON TRAPPING IN PROTON-IRRADIATED SILICON
Authors: XIONG XING-MIN  ,   中国科学院高能物理研究所,北京,100080
Published: November 2020

Positron lifetime measurements are used to investigate positron trapping in silicon irradiated with protons at a high dose of 3.2×1017cm-2 and a lower dose of 3.6×1016cm-2, respectively. The irradiation-induced vacancy defects are mainly divacancies. During the irradiations, the divacancies in high dose samles have almost trapped hydrogens, while a part of the divacancies in low dose samples have not trapped hydrogensyet. In the measurements of the two warm-up of high dosed samples and the first warm-up of low dose samples, the further trapping of hydrogens into divacancies is observed., With increasing temperature the charge state of the divacancies decorated by hydrogens takes a transition from negative to neutral around 145K. With increasing the amount of the trapped hydrogens per divacancy, the lifetimes of the negatively charged divacancy and the neutral one are both shortened, while both their trapping cross sections are increased. The trapping of hydrogens into the negatively charged divacancies has no influence on the temperature dependence of its trpping cross sections.
A STUDY ON CORROSION-RESISTING MECHANISM OF THE ANCIENT MIRROR "HEI QI GU"
Authors: WU YOU-SHI  , WANG CHANG-SUI  , FAN CHONG-ZHENG  , WANG SHENG-JUN  , LI ZHI-CHAO  ,   (1)安徽机电学院,芜湖,241000; (2)中国科学技术大学,合肥,230026; (3)中国科学技术大学,合肥,230026;中国科学技术大学结构分析中心,合肥,230026
Published: November 2020

The surface layer of the bronze mirror "Hei Qi Gu" is composed of non-metal layer and transition layer. The valent electron structure analysis points out that the main phase of tran-sition Sn1-xCuxO2 is similar to SnO2 in stablility. It was found from study of experimental data that there is the coincidence site lattice structure at the phase boundary between the δ-phase Cu-Sn alloy and Sn1-xCuxO2 in the transition layer. This structure reduces the energy of Cu atoms at the phase boundary and makes the δ-phase Cu-Sn alloy stable, which is the main reason for corrosion resistant of the "Hei Qi Gu".
COHERENT-STATE TREATMENT OF NONEQUILIBRIUM BOSE CONDENSATION
Authors: HUANG HONG-BIN  ,   东南大学物理系,南京210018
Published: November 2020

Based on the mean field and Bogoliubov approximations, we linearize the Hamiltonian of a nonequilibrium Bose condensed system, which is created by an external coherent pump field, and coupled to a reservoir. It is found that the dynamical algebra of the linearized Hamiltonian is Heisenberg and SU(1,1) Lie algebra if the coupling to reservoir is not taken into account. By using the methods of coherent state, we obtain its eigenvalues and eigen-functions-direct product of displaced squeezed-number-states and generalized SU(1,1) coherent states. Then we introduce the retarded Green's functions of elementary excitations to calculate its spectrum in the coupling situation, and further give the state functions of exciton system in weakly coupling situation.
TEMPORAL SQUEEZING IN THE RADIATION OF THE FLUORESCENCE FROM A DRIVEN THREE-LEVEL ATOM
Authors: YANG GUO-JIAN  , HU GANG  ,   北京师范大学物理系,北京100875
Published: November 2020

The fluorescence spectrum from a three-level atom in V configuration driven by strong coherent laser fields and the time-dependent squeezing effect in the fluorescence fields with different mixtures of the spectrum lines are investigated analytically.
OPTICAL METRIC DESCRIPTION OF A STRONG LASER-PLASMA
Authors: ZHU SHI-TONG  , SHEN WEN-DA  ,   (1)上海科学技术大学物理系,上海201800; (2)中国科学院上海光学精密机械研究所,上海201800
Published: November 2020

The optical metric of a strong laser plasma is obtained by using the self-consistent density profile and the ponderomotive force potential for one dimensional isothermal expanding plasma. Its physical signification is explained.
THE AVERAGE BOND ENERGY AND THE VALENCE-BAND EDGE OFFSET AT THE INTERFACE OF STRAINED SUPERLATTICE InAs/InP
Authors: KE SAN-HUANG  , WANG REN-ZHI  , HUANG MEI-CHUN  ,   厦门大学物理系,厦门361005
Published: November 2020

The electronic structures of the strained superlattice (SLS) (InAs)1 (InP)1 (001)under two strain conditions (free-standing model and InP-substrate model) and the strained bulk materials corresponding to the molecular layers in the SLS as well as the unstrained bulk materials are calculated with the ab initio LMTO band structure method. The average bond energy of molecular layers in the two SLS are determined with the frozen-potential approach. The results show that the average bond energies are well aligned across the interfaces and this alignment is not almost affected by the condition of strain. Thus, the average bond energy can be considered as a very reasonable reference energy level for determined the valence band offset in SLS. The strain effects on the band structures of molecular layers in SLS and on the △Ev values are investigated. Results given by frozen potential approach and using Em as a reference level in this paper are in good agreement with the available experimental datum from XPS measurement.
MATRIX OF OPTICAL ARRAY AND ITS OPTICAL PROPERTIES
Authors: SHEN KANG-MIN  , DING YUE-MING  ,   (1)杭州大学物理系,杭州310028; (2)杭州大学物理系,杭州310028;浙江省安吉县第一中学(梅溪镇),313306
Published: November 2020

The matrix of optical array with aperture in the element is presented by the Fresnel diffraction intergral. The synthetical imaging aberration of the array is dicussed, the condition of eliminating such aberration is satified with α,β, γ,δ conditions. The reference plane should be shifted with the moving of the aperture in the element.
EFFECTS OF NEXT-NEIGHBOR HOPPING INTERACTIONS ON THE ELECTRONIC BOUND STATES AND LOCALIZED MODES AROUND A SOLITON IN TRANS-(CH)x
Authors: AN ZHONG  , LI ZHAN-JIE  , YAO KAI-LUN  ,   华中理工大学物理系,武汉430074
Published: November 2020

We have studied electronic bound states and the localized modes around the soliton after turning on the next-neighbor hopping interaction, based on SSH model. The results show that (1) the electronhole symmetry of the energy band structure implied by SSH model is broken ; (2) the number and location of the bound states trapped by the soliton have changed; (3) a new localized mode have been found; (4)the frequencies of modes have shifted and their localization are strengthened.
RENORMALISED STRESS-ENERGY TENSOR OF CONFORMAL SCALAR FIELD IN BOULWARE STATE IN REISSNER-NORDSTR?M SPACE-TIME
Authors: HUANG CHAO-GUANG  ,   中国科学院高能物理研究所,北京100039
Published: November 2020

The renormalised stress-energy tensor of a conformal invariant scalar field in the Boul-ware stale in Reissner-Nordstr?m sapace-time is calculated by using the Page-Zannias method and with the help of a personal computer and REDUCE language. The tensor vanishes inthe asymptotically flat region and is not regular at the event horizon.
BREAKING OF SUPERSYMMETRY AND WITTEN INDEX IN TWO-DIMENSIONAL SUPERSYMMETRIC MODELS
Authors: YU YANG-ZHENG  , CHEN XIONG-XIONG  ,   (1)厦门大学物理系,厦门361005; (2)中国科学院理论物理研究所客座,北京100080
Published: November 2020

We construct a wider class of O(N) supersymmetric (SUSY) models with so-perpotential W = (l/n)gφn in two-dimensions. The witten index △ of the models is evaluated in detail. It is shown that SUSY breaking does not occur when n is even, and can occur when n is odd. By using large-N expansion, a mechanism for spontaneous SUSY breaking is investigated. Finally, we present the particle spectra.
IMPROVED KELDYSH-FAISAL-REISS THEORY
Authors: CHEN BAO-ZHEN  ,   北京师范大学低能核物理研究所,北京100875
Published: November 2020

In the framework of Keldysh-Faisal-Reiss (KFR) theory, with taking the coupling bet-ween the atomic potential and the applied light fields into account, the original KFR theory is improved and a new expression of photoionization probability of atoms is obtained.From this new expression, photoelectron spectra of H-atom ATI by strong linear-polarized laser in the short-pulse regime are got. This calulated photoelectron spectra are rather similar to the experimental ones. A new explanation of the experimental spectra is given.
DETERMINATION OF ORDERED STRUCTURES IN FACE-CENTRED CUBE INTERSTITIAL SOLUTIONS
Authors: NI JUN  , WANG SHI-FAN  ,   清华大学现代应用物理系,北京100084
Published: November 2020

The probability wave theory of atomic configuration is employed to study the most stable superlattices formed in fcc interstitial solutions. Eight basic ordered structures are deduced for octahedral interstices and seven basic ordered structures are deduced for tetragonal interstices.
A STUDY ON STRUCTURAL STABILITY OF BUFFER LAYER BETWEEN SILICON SUBSTRATE AND DIAMOND FILM
Authors: ZHANG XIAO-PING  , GAO ZHI-QIANG  , SUN BI-WU  , XIE KAN  , LIN ZHANG-DA  ,   中国科学院表面物理国家重点实验室,北京100080
Published: November 2020

High-quality diamond films are grown on Si substrate by hot filament chemcial vapor de-position (HFCVD). With increase of growth time, pure carbon species and mixtures of them are also identified by X-ray photoelectroscopy (XPS) and auger electron spectroscopy (AES). To describe the buffer layers, a gradient model is proposed as Silicon/Si1-xCx/SiC/SiyC1-y/ Diamond. Within the range of 0.10<x, y<0.25, the structural stability is studied by Keating potential.
STUDY ON STRUCTURAL AND VIBRATIONAL PROPERTIES OF AMORPHOUS SILICON FILMS USING A SIMULATING ANNEALING MODEL
Authors: YU GONG  , HAO MAO-SHENG  , ZHANG FANG-QING  , CHEN GUANG-HUA  ,   兰州大学物理系,兰州730001
Published: November 2020

We have performed simulating annealing in computer by using Monte Carlo technique to produce a random-network model of amorphous silicon. The structural characteristics of this model is in good agretment with that of real sample. Its vibrationol densities of states have been calculated with molecular-dynamics method. The relationships between its locaiized vibrational modes and the structural defects have also been discussed.
CALCULATION ON THE HARMONIC DIFFRACTION OF SYNCHROTRON RADIATION X-RAYS
Authors: YANG PING  , ZHAO JI-YONG  , JIANG JIAN-HUA  ,   (1)南京大学固体微结构物理国家实验室,南京210008; (2)中国科学院高能物理研究所同步辐射实验室,北京100039
Published: November 2020

The formula of harmonic diffraction from a perfect crystal is worked out based on the concept of dynamical diffraction and the spectrum of synchrotron radiation. As an applica-tion, the harmonic diffraction from several commonly used planes of Si crystal is calculated, which reveals that there are more harmonics in the chosen (333) diffraction than the other planes. The data are merely true for the Topography Station at Beijing Synchrotron Radia-tion Lab. (BSRL), Beijing Electron-Positron Collider (BEPC).
THEORY OF THREE-DIMENSIONAL QUANTUM SPIN GLASS (I)——STATIC REPTICA SYMMETRY APPROACH
Authors: YI LIN  , YAO KAI-LUN  ,   (1)华中理工大学物理系,武汉430074; (2)中国高等科学技术中心(世界实验室),北京100080
Published: November 2020

By employing the imaginary time functional technique and the so-called replica method, a quantum vector spin glass model with random Dzyaloshinskii-Moriya anisotropy and ferro-magnetic interaction is investigated for any spin quantum numbers. In the static replica sym-metry limit, the spin self-interaction order parameters, the spin glass order parameters and the magnetization are all determined self-consistently. The relation between susceptibility tensors and order parameters is set up. Compared with other methods, our theory works at all tempe-ratures.
STRUCTURE OF THE ENERGY SPECTRUM FOR THE BOUND STATES OF A CHARGED FERM1ON AND A DIRAC DYON WITH ZZd?137
Authors: QI YONG-CHANG  ,   山西大学物理系,太原030006
Published: November 2020

It is found that the energy spectrum of the bound states of a charged fermion and a Dirac dyon is divided into many series of spectral lines according to the different K=n + [μ]integer as ZZd?137. The features of the structure are discu-ssed. The Zeeman effect for the system is also discussed.
KUSTANNHEIMO-STIEFEL TRANSFORMATION FOR MESON STRUCTURE MODEL WITH A FOUR-DIMENSIONAL HARMONIC OSCILLATOR
Authors: LONG JUN-YAN  , LI GUANG-HUA  , KUANG LE-MAN  ,   长沙水利电力师范学院物理系,长沙410077
Published: November 2020

By use of the Kustannheimo-Stiefel transformation, the problem of a four-dimensional covariant harmonic oscillator can be transformed to that of a three-dimensional hydrogen atom with constraint. On this basis, the difficulty of the excitation of the time degree of freedom can be avoided naturally and the mass-squared formula for mesons can be obtained.
A SIMPLIFIED COMPUTATIONAL SIMULATION APPROACH OF FREE ELECTRON LASERS
Authors: ZHANG SHI-CHANG  , WANG WEN-YAO  , XU YONG  ,   (1)西南交通大学应用物理系,成都610031; (2)中国高等科学技术中心(世界实验室)理论物理分中心
Published: November 2020

A simplified computational approach of free-electron lasers is proposed,which is suitable to the operation on micro-computers. The saturation output laser powers from the simulation on a micro-computer (AST386/33L)by means of this simplified approach are in agreement with the data measured in the MIT's experiment.
FORMATION PROCESS OF PHASES IN BINARY PLANAR DIFFUSION COUPLE
Authors: ZHAO YUE-CHAO  , XIAN DING-CHANG  , WU ZI-QIN  ,   (1)中国科学技术大学基础物理中心,合肥230026; (2)中国科学院高能物理研究所,北京100039
Published: November 2020

In this paper a description for the phase formation in a binary planar diffusion couple is presented in the form of a system of differential equations. Not only diffusivity of constituents but also interfacial reaction at phase boundary are introduced in this system of equations. The formation process of phases including the sequence, the growth or shrinkage of the phases can be described clearly with this system of equations. The analysis on the basis of these equations indicates that the formation process of phases depends on interfacial reaction as well as of diffusion. Finally, two typical experimental results are expounded.
ORDERED STRUCTURES AND ELECTRONIC PROPERTIES OF (GaAs)1-xGe2x SYSTEM
Authors: DUAN WEN-HUI  , WANG SHI-FAN  , NI JUN  , GU BING-LIN  , ZHU JIA-LIN  ,   (1)清华大学现代应用物理系,北京100084; (2)清华大学现代应用物理系,北京100084;山东矿业学院物理教研室,泰安271019
Published: November 2020

The stable ordered structures of (GaAs)1-xGe2x system have been studied, using the probability wave theory of the atomic configuration (PWAC). Based on the determination of the ordered structures, the electronic structures of five typical stable ordered structures for x = 0.5 are investigated by the use of first principle self-consistent LMTO method. The calculated results show that the electronic properties of different ordered structures can be quite different. The more Ga-Ge and Ge-As atomic bonds in unit cell of ordered structures are, the more possible the ordered structures are expected to exhibit a metallic character.
PHOTOLUMINESCENCE OF Be-DOPED-GaAs QUANTUM WELLS
Authors: CHENG WEN-QIN  , MEI XIAO-BING  , ZHOU JUN-MING  , LIU YU-LONG  , ZHU KE  ,   中国科学院物理研究所,北京100080
Published: November 2020

The photoluminescence of Be-doped GaAs quantum wells with width of 10 nm was measured at 4.2 K. The doping concentration is about 1×1017 and 5×1018cm-3. The results showed that the product of the density of states of acceptors and the probability of transition from conduction subband n=l to neutral acceptors at the well center is larger than that near the interface of GaAs and AlGaAs. In addition, the ionization energy of acceptors is decreased as doping concentration is increased. It is due to band-gap narrowing with the doping concentration of p-type GaAs.
CALCULATIONS OF POSITRON SCATTERING BY ATOMIC HYDROGEN BASED ON A MULTIPLE-SCATTERING EXPANSION METHOD
Authors: LI SHAO-PU  , LIU QIANG  , XU XIANG-DONG  , QIAN QING  , CHEN XUE-JUN  ,   (1)清华大学现代应用物理系,北京100084; (2)中国高等科学技术中心(世界实验室)理论物理分中心
Published: November 2020

Calculations are conducted for the differential cross sections of elastic scattering of atomic hydrogen by positron in the energy range of 50-300 eV based on a multiple-scattering expansion method. Discussion of the present results is given and comparison is made with other current theoretical calculations.
A STUDY ON "WATER WINDOW" RANGE 2p-3d POPULATION INVERSION OF He-LIKE AI IONS X-RAY LASER
Authors: XU ZHI-ZHAN  , HAN SHEN-SHENG  , SHEN BAI-FEI  , JIANG ZHI-MING  , SUN LAN  , FAN PIN-ZHONG  , WANG XIAO-FANG  , QIAN AI-DI  ,   中国科学院上海光学精密机械研究所,上海201800
Published: November 2020

The results of experimental and theoretical study on population inversion in the He-like Al ions are presented for the pumping laser intensity range of ～2×1014W|cm2. The effects of different target structure (foil, plane and half-cylinder) on the 2p-3d population inversion of the He-like Al ions (45nm) in a spot focused laser plasma have been studied experimentally. The plasma parameters such as electron temperature, electron density and the ratio of H-like ion density to He-like ion density, are diagnosed by spectroscopic methods. Results are compared with C-R model calculations.
ENERG LEVELS OF HYDROGEN ATOM IN MAGNETIC FIELD OBTAINED BY USING B SPLINE BASIS SETS
Authors: RAO JIAN-GUO  , XI JIN-HUA  , LIU HONG  , LIU WEN-YU  , LI BAI-WEN  ,   中国科学院武汉物理研究所波谱与原子分子物理开放研究实验室
Published: November 2020

In this article, the B spline technique is employed to calculate the energy values of a number of low-lying states of hydrogen atom in the presence of a homogeneous magnetic field of arbitrary strength (０＜Ｂ≤４．７×１０8T) our results fill the gaps in the results of the works by Rosner et al. and Ivanov, and agree well with those obtained by other theoretical calculations. B spline functions are proved to be powerful in treating the excited, as well as ground states of hydrogen in magnetic field.
THE THEORETIC CALCULATION OF ENERGY DIFFERENTIAL AND INTEGRAL CROSS SECTIONS FOR ELECTRON-HYDROGEN COLLISION
Authors: HU WEI  , WANG YAN-SEN  , FANG DU-FEI  , LU FU-QUAN  , YANG FU-JIA  ,   复旦大学李政道物理学综合实验室和物理二系
Published: November 2020

A distorted wave born exchange (DWBE) approximation is used to calculate the cross section of electron impact ionization for atomic hydrogen. Both the energy differential cross sections and the integral cross sections from calculation are compared with the latest experimental data. The comparison shows good agreement between theoretical and experimental results. The small difference between these results is also discussed.
STUDY ON THE STRUCTURAL AND MAGNETIC PROPERTIES OF RFe10.5V1.5Nx
Authors: YANG YING-CHANG  , DONG SHENG-ZHI  , YANG JUN  ,   北京大学物理系
Published: November 2020

A systematic study on the structural and magnetic properties of the Rfe10.5V1.5Nx series, where R=Y, Ce, Nd, Sm, Gd, Tb, Dy, Ho, Er, has been carried out by X-ray diffraction and magnetic measurements. Rfe10.5V1.5Nx compounds show a higher Curie temperature and a larger saturation magnetization due to the lower content of V compared with Rfe10V2Nx In NdRfe10.5V1.5Nx the c-axis is the easy axis from 0 K to Tc, the anisotropy field is up to 185 kOe at 1.5 k and 102 kOe at room temperature with a combination of a high Curie temperature of 784 K and a large room temperature saturation magnetization of 139.1 emu/g, the intrinsic magnetic properties are favourable for permanent magnet applications.
THE PHOTOLUMINESCENCE SPECTRA SHIFT OF POROUS SILICON BY SPONTANEOUS OXIDATION
Authors: WU XIAO-WEI  , BAO XI-MAO  , ZHENG XIANG-QIN  , YAN FENG  ,   南京大学物理系和固体微结构物理国家重点实验室
Published: November 2020

The light-emission of the porous silicon is an indirect recombination process of the excited electron through the surface states. During spontaneous oxidation new surface states are formed which make the photoluminescence spectra shift.
RENORMALIZATION AND CRITICAL BEHAVIOR OF SINE-GORDON MODEL
Authors: DING GUO-HUI  , XU BO-WEI  , ZHANG YU-MEI  ,   (1)上海交通大学物理系; (2)同济大学物理系
Published: November 2020

Using the Gaussian wave functional method, the ground state and the critical behavior of the continuum and discrte Sine-Gordon model are investigated, the results of the two different renormalization approach are compared.
OPACITY FUNCTION FOR ROTATIONALLY INELASTIC SCATTERING OF Ar+N2 SYSTEM IN IT'S LONG-RANGE POTENTIALS
Authors: REN TING-QI  , LIU SHENG-DIAN  , ZHANG QING-GANG  , ZHANG YI-CI  ,   (1)山东师范大学物理系; (2)烟台师范学院物理系
Published: November 2020

A new method is proposed to deal with the rotationally inelastic scattering of A+BC collision system. The matrix element 0,l/?)t|R′> is obtained analytically, the centrifugal potential takes the CS approximation, the rotationally term in the total Hamiltonian is treated by the Fourier transform and the time-dependent Schrodinger equation is approximated by the SOD method. Using this method the opacity function for Ar+N2 scattering system is calculated. The results show that the method introduced in the present paper is more suitable than the CCWP method in calculating the transition for long-range Ar+N2 potentials. And the calculational efficiency of our method is higher than the latter.
A THEORY OF MW-LATITUDE IONOSPHERIC IRREGULARITIES PRODUCED BY ATMO-SPHERIC GRAVITY WAVES
Authors: HUANG CHAO-SONG  , LI JUN  , M .C. KELLEY  ,   (1)School of Electrical Engineering,Cornell University,Ithaca,New York 14853,USA; (2)中国科学院武汉物理研究所
Published: November 2020

Basic properties of large scale irregularities in the rnid-latitude ionospheric F region and their relationship with atmospheric gravity waves are studied. The temporal evolution of the plasma Perkins instability is analyzed. It is found that the instability saturates at a small amplitude. The coupling between the Perkins instability and gravity waves is discussed and it is shown that gravity waves can initiate the plasma instability in the mid-latitude F region. The plasma instability initiated by gravity waves can evolve into steady-state perturbations, large amplitude wave-like structures, and spatially and temporally modulated irregularities. The theory indicates the production mechanism of the large scale irregularities in the mid-latitude ionosphere.
NEW SYMMETRY THEORY OF THE HIGH-Tc SUPERCO-NDUCTIVITY FOR ELECTRON-PHONON SYSTEMS
Authors: YI LIN  ,   华中理工大学物理系
Published: November 2020

By means of a new Cooper pair mean field approximation, an effective phonon-Cooper pair interaction is derived for electron-phonon systems. It is demonstrated that through exchange of virtual Cooper pairs, phonons with opposite wave vectors can feel an effective attractive force and bound into phonon pairs, which leads to a new superconducting phonon state. It is found that the electron Cooper state and the superconducting phonon state consist of the stable and symmetric superconducting ground state with high critical temperature. In the weak coupling limit of phonon-Cooper pair interactions, the ground state symmetry breaks down and becomes the traditional BCS state.
A PRINCIPLE FOR MICRO-REGION SUPERPOSITING OF ION SPUTTERING
Authors: WANG ZHEN-XIA  ,   中国科学院上海原子核研究所
Published: November 2020

Solid surfaces subjected to energetic ion bombardment generally develop chara-cteristic structures, which may significantly change total and differential sputtering yields. The change is due to several competing effects, for instance, change of the effective projectile incidence angle, recapture of obliquely ejected particles (shadow effect), and element local-enrichment in different micro-region on the alloy surface. From these, we have now developed an efficient new theoretical method for covering all of the above effects exactly. This method and its application to the analysis of experimental results of element (Cd) and alloy system (ＡｌxSn１００－x)targets are de-scribed in detail.
ENTROPY-LIKE QUANTITY OF THE EQUILIBRIUM ELECTRONS IN A FREE-ELECTRON LASER WITH REVERSED GUIDE FIELD
Authors: ZHANG SHI-CHANG  , LIU QING-XIANG  , XU YONG  ,   (1)西南交通大学应用物理系; (2)中国高等科学技术中心(世界实验室)理论物理分中心; (3)中国工程物理研究院电子工程研究所
Published: November 2020

Nonlinear simulation of the entropy-like quantity is given to the equilibrium electrons in a free-electron laser with reversed guide field. Results indicate that the quality of the electron beam may be better than the oae in the case of positive guide field. However, the quality of the beam is spoiled at the antiresonance. The concl-usions from the entropy-like quantity principally coincide with the experiment made by the MIT researchers.
A MIXED IMPURITIES MODEL OF THE ONE-DIMENSIONAL LATTICE
Authors: FAN HONG-YI  , XU ZHI-HUA  ,   中国科学技术大学材料科学系
Published: November 2020

We study a tight binding model Hamiltonian of the one-dimensional Bravais lat-tice. This Hamiltonian contains one impurity energy site and two hopping constants between this site and its two nearest neighbours. The formation and properties of the localized states of this model is analysed by virtue of the Green function method.
MEASUREMENT OF THE BAND OFFSET IN GexSi1-x/Si SINGLE QUANTUM WELL BY USING SINGLE FREQUENCY ADMITTANCE SPECTROSCOPY
Authors: LU FANG  , JIANG JIA-YU  , GONG DA-WEI  , SUN HENG-HUI  ,   (1)复旦大学物理系; (2)复旦大学应用表面物理国家重点实验室
Published: November 2020

A single frequency admittance spectroscopy technique is introduced for determining the band discontinuity on Si/GexSi1-x/Si single quantum well (SQW). By using this method, the more accurate experimental results can be obtaind from a single frequency admittance spectrum. For an alloy with composition x=0.33，we get the activation energy Ea＝0.20eV. In order to obtain the value of the band offset，it is necessary to determine the position of Fermi level which depends on the dopam concentration inside and outside the well, the band offset of hetero-interface and temperature. By solving Poisson equation, we get the energy band diagram and Fermi level of the test sample. It is shown that the Fermi level lies about 40 meV above the top of valance band in the well. And due iv the carrier transfer at the hetero-interface, the carrier concentration (about ２×１０17ｃｍ－３) in the well is one order large than dopant concentration(1×１０16ｃｍ－３). The energy bands at two sides of the interfaces are bent by about 0.006 eV in the well and O.11eV in the barrier, hence the valance band offset can be calculated as 0.16eV. The accuracy of this technique can also be verified from reconstruction of C-T and G-T curves by cumputer simulation.
BARIUM-DOPING EFFECTS ON THE SUPERCONDUCTIVITY OF Bi2Sr2CaCu2Oy
Authors: YANG BEI-FANG  , M. J. G. LEE  , J. M. PERZ  , XU CUN-YI  , ZUO JIAN  , WANG LIANG-BIN  , RUAN YAO-ZHONG  , ZHANG YU-HENG  ,   (1)多伦多大学物理系和Scarborough学院; (2)中国科学技术大学材料科学与工程系; (3)中国科学技术大学结构分析开放研究实验室
Published: November 2020

Ba-doping effects on the superconducting properties in the Bi2Sr2-xBaxCaCu2Oy single crystals (0≤x≤0.15) and polycrystalline samples (0≤x≤0.3) have been studied. The results show that Ba２＋ enters the superconducting phase with a solubi-lity limit. For 2212 phase single crystals, the length of c-axis and the supercondu-cting transition temperature Tc both increase with increasing Ba content. For slowly cooled sintered samples, Tc is significantly increased by Ba doping, whereas for quenched samples Tc is little affected. Changes in Tc with Ba doping have been explained by changes in the hole concentration.
ANALYSIS OF POSITRON ANNIHILATION LIFETIME SPECTRUM BY FAST FOURIER TRANSFORM
Authors: MA JIAN-GUO  , GUO YING-HUAN  , WANG YUN-YU  ,   中国科学院高能物理研究所,北京100039
Published: November 2020

This work is the first attempt to decompose the positron annihilation lifetime spectrum into the form of a frequency spectrum by Fast Fourier Transform (FFT) technique. Each real peak in the frequency spectrum indicates a lifetime component. The peak position corresponds to the annihilation constants, the peak area is proportional to the intensity of the component. The principle of this method is described in this paper. We thoughtfully consider the effects of the instrumental resolution function and the statistical error. A program is compiled with Turbo C and successfully operated on PC ALR-286. The analysis results for some simulated spectrum are satisfactory. The work indicates that the advantages of this method are its simplicity, rapidity, less effect of the instrument resolution function and no guessing what the components are before analysis.
NONLINEAR BEHAVIOR OF STIMULATED RAMAN SCATTERING IN INHOMOGENEOUS PLASMA
Authors: WANG WEI-XING  , CHANG TIE-QIANG  , SU XIU-MIN  ,   北京应用物理及计算数学研究所
Published: November 2020

Nonlinear behavior of stimulated Raman scattering (SRS) in inhomogeneous plasma is investigated numerically with aperiodic boundary conditions. The effects that modify SRS behavior with stimulated Brillouin scattering (SBS) and Langmuir driven ion fluctuation are 1) nonlinear coupling of Langmuir/ion acoustic wave and 2) energy competition between SRS and SBS. The various processes of the nonlinear coupling which may inhibit SRS are discussed and the SRS evolution features are illustrated in inhomogeneous 1D plasma. Langmuir wave conversion to more strongly damped waves appear to be important to suppress SRS. The γeff,R/γeff,B, the ratio of growth rates of SRS and SBS, and lR/lB, the ratio of growth lengths are presented as two important parameters to define the different paths of simutaneous SRS/SBS evolution. When γeff,Reff,B or lR/lB, SBS is potent to saturate even terminate SRS.
THE DEEP LEVEL STUDIES OF n-Si/n+-Si INTERFACE IN SILICON DIRECT BONDING
Authors: LU LI-WU  , ZHOU JIE  , FENG SONG-LIN  , QIAN ZHAO-MING  , PENG QING  ,   (1)北京半导体超晶格国家重点实验室,中国科学院半导体研究所; (2)浙江大学电力电子技术研究所
Published: November 2020

The deep levels of n-Si/n+一Si interface and near the interface in the n-Si have been studies using spread resistance probe (SRP) and deep level transient spectroscopy (DLTS) techniques in silicon direct bonding. The experimental results show that a dominant electron trap, having energy level position of Eｃ－0.39eV and concentration in the range of l013－１０14ｃｍ-3, was observed. This trap is strongly related to vacancies of n-Si/n+-Si interface and near the interface in the n-Si induced by high temperature(1000一11000C) treatment in SDB processing.
THE ELECTRONIC STRUCTURE OF MoSi2(001)SURFACE
Authors: ZHANG HAI-FENG  , HUANG XIN-TANG  , LI YONG-PING  ,   (1)中国科学技术大学结构分析开放研究实验室,华中师范大学物理系; (2)中国科学技术大学结构分析开放研究实验室,中国科学技术大学材料科学与工程系; (3)中国科学技术大学结构分析开放研究实验室,中国科学技术大学物理系
Published: November 2020

The electronic stucture of three kinds of MoSi2(001)surface with C11b crystal structure were studied by using LMTO一ASA method, their surface total electronic densities of states and local densities of states of surface layer as well as partial densities of states, were provided and compared with the correlated atomic bulk densities of states. As to the stability of the surfaces, the densities of states on Fermi level's were discussed, the Si monolayer surface is the most stable one among them, which support the experimental results obtained by Kemoda et al.
MICROWAVE JOINING OF Y-123 SUPERCONDUCTORS AND ITS EFFECT ON THE MICROSTRUCTURE
Authors: ZHANG LIU-WAN  , XIE XIAO-MING  , CHEN TING-GUO  , CAI JIE  , LI XIANG-TING  , TIAN YONG-LAI  , GUO JING-KUN  ,   (1)中国科学院上海硅酸盐研究所; (2)中国科学院上海冶金研究所
Published: November 2020

The microwave joining of Y-123 superconductors was studied. It was discovered that after joining the joined region became denser and some impurities such as Ｙ2ＢａＣｕＯx,Ｂａ2-yＣｕyＯx and CuO were easyly detected. After post-annealing in air at 960℃ for 15h and cooled to room temperature, Ｙ2ＢａＣｕＯx was obviously diminished, Ｂａ2-yＣｕyＯx almost disappeared completely. And Tc of the joined specimen was 89.7, 1.6K lower than that of the original sample. But during the post-treatment, the superconductor in the joined region was recrystallized, the joined region was widened and the holes were enlarged.
HAWKING RADIATION OF CHARGED DIRAC PARTICLES IN GENERAL SPHERICALLY SYMMETRIC AND NON-STATIC SPACE-TIME
Authors: YANG BO  , ZHAO ZHENG  ,   (1)北京师范大学物理系; (2)北京师范大学物理系,四川万县师范专科学校物理系
Published: November 2020

Hawking radiation of charged Dirac particles near the event horizons of the general spherically symmetric and non-static black holes is studied. We obtain the equation determining the location of event horizon, the radiation temperature function and the Hawking thermal spectrum formula.
DIFFRACTION PROPERTIES OF PHOTORE-FRACTIVE GRATINGS
Authors: GUO RU  , LING ZHEN-FANG  ,   南开大学物理系
Published: November 2020

Based on the forward four-wave mixing model, we abtain analytic expressions for the diffraction efficiency of the photorefractive gratings with weak reading beam and strong reading beam intensity respectively for various values of the spatial phase shift between index change and fringe pattern.
INFLUENCE OF UNTRAPPED ELECTRONS ON THE SIDE-BAND INSTABILITY OF ELECTROMAGNETIC WIGGLER FREE ELECTRON LASER
Authors: MENG LIN  , LIU SHENG-GANG  ,   电子科技大学高能电子学研究所
Published: November 2020

Influence of untrapped electrons on the sideband instability of electromagnetic Wiggler free electron laser (EM一FEL) is analyzed in detail with single-particle theory. The dispersion equation is derrived by applying the methode in Ref.[1]，and detailed discussions are carried out, some conclusions are drawn.
GROUND-STATE ENERGY OF THE POLARON IN A QUANTUM WELL WITHIN CONS I ANT ELECTRIC AND MAGNETIC FIELDS
Authors: HUANG ZHUO-HE  , CHEN CHUAN-YU  , CHEN ZHI-DE  , ZHANG SHU-QUN  ,   (1)广州师范学院物理系; (2)中国高等科学技术中心(世界实验室)理论物理分中心
Published: November 2020

In this paper, the system of the electron-bulk LO-phonon interaction in a quantum well within constant electric and magnetic fields along the growth axis, is analysed by the method of variational wave-function and harmonic oscillator operator algebra. The representation of the ground state energy which includes the correction of the second-order perturbation is obtained as a funtion of the electron-LO-phonon coupling constant, the width of the quantum well, the strength of the electric and magnetic field. The results have shown that, the polaronic correction to electron ground state energy reduces with increasing well width and electric field, but enhances with increasing magnetic field.
NON-PROPAGATING SOLITARY SURFACE WAVE IN A CHANNEL WITH UNIFORMLY AND SLOWLY VARYING WIDTH
Authors: YAN JIA-REN  , ZHU SONG-HUI  , LI HONG  ,   (1)湖南大学继续教育学院; (2)湘潭大学物理系
Published: November 2020

The nonlinear equation governing the non-propagating solitary wave and its analytical solution in a channel with uniformly and slowly varying width has been derived using the perturbation theory of multiple scales. The result obtained predicts that the solitary wave always moves towards the narrow end of the channel with an approximately uniform acceleration which is proportional to the variation rate of the width. The method in the present paper can be extended in principle to the theoretical investigation of other linear and nonlinear waves in a uniformly and slowly varying wave guide.
PARAMETRICLLY EXCITED SOLITARY WAVES IN A TROUGH RESONATOR
Authors: CHEN LU-JUN  , LIANG CHANG-HONG  , WU HONG-SHI  ,   西安电子科技大学
Published: November 2020

Based on equations of fluids nachanics, introducing new scale hypotheses, and by means of pertubative multiple-scale method, the governing equation and solution of non-propagating soliton wah counting of excition and damping are given. By damping analysis, the curves of the lower cut-off excited amplitude△ｃ versus the excited frenquency Ω and the soliton equalamplitude curves in △－Ω picture in a good agreemant with experiment to a certain extent are obtained.
SMALL-ANGLE X-RAY DIFFRACTION IN ANALYSES OF THE STRUCTURE OF COATINGS
Authors: SHAO JIAN-DA  , FAN ZHENG-XIU  , YIN GONG-JIE  , YUAN LI-XIANG  ,   中国科学院上海光学精密机械研究所
Published: November 2020

The period thickness mean refraction corrected factor and the ratio between two difference materials in a period can be deduced from the Bragg equation with refraction correction. Based on this Bragg's law and theory of optical thin film, the formula introduced in this paper have been verified in theory and experiment with short-period Mo/Si multilayers.
NUCLEATION MECHANISM OF THE SOLID PHASE CRY STALLIZATION OF a-Si:H FILMS CONTROLLED BY LIGHTLY DOPING IN LOW-TEMPE-RATURE ANNEALING
Authors: DU KAI-YING  , RAO HAI-BO  ,   四川大学物理系
Published: November 2020

By lightly doping in a-Si: H films in the process of low-temperature annealing, the density of the nualeation centers was controlled, and the films of larger grain polysilicon with good quality were obtained. The results show that the crystallization was almost uniformly proceed in(， and direction (slightly faster in direction), the average grain size is about 1μm, the mobility is about 92 cm２/V·s, and the dark conductivity at room-temperature is between 10-２s/cm and 10-4s/cm. The optical gaps of the crystallized films were determined between 1.16-1.22eV from the absorption spectrum. The coefficient of optical absorption within the wave length range of 800-1000nm is on the order of 104cm-1, and the absorption efficiency is around 60%.The results of heavily doped annealing samples of a-Si:H, as a contrast, are also discussed.
On algorithms for computing the sums of powers of arithmetic progressions
Authors:   Department of Mathematical Sciences, University of Nevada, Las Vegas,, Shiue Peter J. , Huang Shen C. ,   Department of Mathematical Sciences, University of Nevada, Las Vegas,, Jameson Eric ,   Department of Mathematical Sciences, University of Nevada, Las Vegas,
Published: November 2020

This paper is concerned with sums of powers of arithmetic progressions of the form a^p+(a+d)^p+(a+2d)^p+\cdots+(a+(n-1)d)^p, where n\geq 1, p is a non-negative integer, and a and d are complex numbers with d\neq 0. This paper gives an elementary proof to a theorem presented by Laissaoui and Rahmani [9] as well as an algorithm based on their formula. Additionally, this paper presents a simplification to Laissaoui and Rahmani’s formula that is better suited to computation, and a second algorithm based on this simplification. Both formulas use Stirling numbers of the second kind, which are the number of ways to partition p labelled objects into k nonempty unlabelled subsets [4]. An analysis of both algorithms is presented to show the theoretical time complexities. Finally, this paper conducts experiments with varying values of p. The experimental results show the proposed algorithm remains around 10% faster as p increases.
Research Development on Wiper Mechanism in Automotive Application: A Critical Review
Authors: Sharveswaran A. , Nirmal Umar
Published: November 2020

In this generation, usage of transportation vehicles is drastically increased. It is very important to improve the safety facility in an automobile vehicles. Due to this, many researchers have contributed to research and development on smart wind shield wiper mechanism in automotive. Considering that, the current work compiles a compilation of articles reviewed on smart wind shield wiper mechanism from year 1903 to 2015. Further than that, this work also provides information relating to the varying designs and specifications of smart windshield wiper mechanism. At the same time, the writers also propose potential future research that could be undertaken in relation to the development in wiper mechanism in automotive application, which in turn may allow for new research pathways in this area of interest. Finally, taking into consideration the design and safety factors of the current market trend wiper mechanism, the writes also propose possible windshield washing system for various application.