bluuebunny/crossref_metadata_2025 huggingface dataset:
Diamond-like carbon films deposited on optical glass substrate by using ECR microwave acetone plasma CVD method
Authors: Yang Wu-Bao  , Wang Jiu-Li  , Zhang Gu-Ling  , Fan Song-Hua  , Liu Chi-Zi  , Yang Si-Ze  ,   (1)中国科学院物理研究所，北京 100080; (2)中国科学院物理研究所，北京 100080;石油大学（北京）材料科学与工程系，北京 102249
Published: December 2020

Smoothing, dense and uniform nano-crystalline diamondlike carbon films are pr epared by using electron cyclotron resonance (ECR) microwave acetone plasma chemical vapor deposition (CVD) method. Atomic force microscope shows that, the surface roughness of this film is less than 10nm, the average grain size is abou t 100nm, and there are no distinct Raman shift peaks. Middle infrared spectra sh ow the existence of sp1, sp2, and sp3 mixed C—C bond, sp3 mixed CH3,CO, COOH and other oxygenic hydrocarbons in the film. The micr ohardness is about 4GPa, bulk elastic modulus is about 11 GPa tested by nano-indentation. Without absorption in closed infrared area, the refractive index is 1.576 and the calculated deposition rate is 460 nm/h for the film.
A study of U-shaped micromachined cantilever array
Authors: Yu Xiao-Mei  , Zhang Da-Cheng  , Wang Cong-Shun  , Li Ting  , Ruan Yong  ,   北京大学微电子学研究所，北京 100871
Published: December 2020

In order to increase the resolution and realize the versatility of cantilever, U-shaped piezoresistive cantilever array has been designed and fabricated in this research. The optimized geometries of cantilever and piezoresistor were determined by analyzing the stress, noise and sensitivity of piezoresistive cantilever from theory. Based on silicon micromachining technology, the piezoresistive cantilevers were fabricated by using polysilicon as the piezoresistive materials. With the measurement results of noise and sensitivity, the Hooge factor was calculated to be 3×10-3, the gauge factor is 27, and the minimum detectable deflection of piezoresistive cantilever was calculated to be 0.5nm at a 6V bias voltage and a 1000Hz measurement bandwidth. The noise sources of polysilicon pizeoresistor are also discussed in this paper.
Emission spectral tomography algorithm based on multi-objective optimization and its application in plasma diagnosis
Authors: Wan Xiong  , Yu Sheng-Lin  , Wang Chang-Kun  , Le Shu-Ping  , Li Bing-Ying  , He Xing-Dao  ,   (1)南昌航空工业学院测控系,南昌 330034; (2)南昌航空工业学院测控系,南昌 330034;南京航空航天大学自动化学院,南京 210016; (3)南京航空航天大学自动化学院,南京 210016
Published: December 2020

A multiobjectiveoptimizationbased emission spectral tomography alg or ithm(EST) is proposed. Its reconstruction results for asymmetrical emission coefficient field are studied by numerical simulation with compute r. The results show that this algorithm has faster convergences and higher recon struction precision than that of traditional algorithms and is suitable for real time reconstruction of emission coefficient field with incomplete data. In the experiment of argonarc plasma diagnosis, the threedimensional reconstructio ns of temperature and atomic (ionic) density fields are accomplished with this a lgorithm and the spectrum relativeintensity method.
Structural and optical studies of MgxZn1-xO films grown on sapphire
Authors: Chen Nai-Bo  , Wu Hui-Zhen  , Qiu Dong-Jiang  ,   (1)浙江大学物理系,杭州 310028; (2)浙江大学物理系,杭州 310028;信息功能材料国家重点实验室，中国科学院上海微系统与信息技术研究所,上海 200050
Published: December 2020

Low-temperature epitaxy of MgxZn1-xO thin films is achieved on sapphire substrates by the reactive electron beam evaporation. X-ray diffraction (XRD) and energy dispersive x-ray (EDX) analyses of the films demonstrate that the structure of MgxZn1-xO depends upon the concentration of Mg in the films. With the increase of Mg concentration, the structure of MgxZn1-xO changes from the wurtzite crystal structure of ZnO to the cubic one with lattice constant similar to that of MgO. By the measurements of UV-visible transmission and ultraviolet photoluminescence spectra of the MgxZn1-xO films, it is found that the absorption band edge of MgxZn1-xO is blue shifted obviously with the increase of Mg concentration, indicating the absorption band edge of MgxZn1-xO becomes wider. However, the lattice mismatch between cubic MgxZn1-xO film and MgO is small (0.16%).
Analysis of the characteristics of low-frequency modes in a corrugated waveguide filled with plasma
Authors: Xie Hong-Quan  , Liu Pu-Kun  , Li Cheng-Yue  , Yan Yang  , Liu Sheng-Gang  ,   (1)电子科技大学高能电子学研究所，成都 610054; (2)西南科技大学理学院，绵阳 621002; (3)中国科学院电子学研究所，北京 100080
Published: December 2020

A corrugated waveguide filled with an infinitely thin annular plasma is immersed in a strong longitudinal magnetic field. By means of fluid model and linear field theory，the dispersion relation of the electromagnetic wave propagation along the system is derived. The dispersion characteristics and beamwave interactions of lowfrequency plasma modes are analyzed in two cases of various densities of plasma by numerical computation. It is found that the dispersion relation with out electron beam satisfies exactly the Floquet theorem and the frequency of electromagnetic wave could not be confined by plasma oscillation frequency. The low-frequency plasma modes can even be coupled with TM modes as the plasma density i s increased.
Preparation and thermal transport properties of CoSb3 nano-compounds
Authors: Yu Bai-Lin  , Tang Xin-Feng  , Qi Qiong  , Zhang Qing-Jie  ,   武汉理工大学材料复合新材料国家重点实验室，武汉 430070
Published: December 2020

CoSb3 micrometer powder was synthesized by solidstate reaction using high pu rity powder of Co,Sb as the starting materials.CoSb3 nano-powder was prepared by highenergy ballmilling.CoSb3 block material with the average grain size of 150nm was prepared by Spard Plasma Sintering(SPS).The influence of nanostru cture on thermal transport properties of CoSb3 was investigated systematicall y .When the grain size of CoSb3 decreases from micrometer to namometer,the lattice thermal conductivityκL of compounds falls remarkably,while the carries thermal conductivity κc decreased less drastically than did the lattice thermal conductivity κL.The decrease in thermal conductivity of CoSb3 compounds with decreasing grain size was mainly due to the reduction in lattice thermal conductivity.
First principle study on optical properties of KTa0.5Nb0.5O3
Authors: Wang Yuan-Xu  , Wang Chun-Lei  , Yuan Min  , Zhao Ming-Lei  , Zhong Wei-Lie  ,   山东大学物理与微电子学院，济南 250100
Published: December 2020

We have calculated the optical properties(the imaginary part of the dielectric f unction ε2(ω),the optical absorption coefficient I(ω),the reflectiv ity R(ω)) of tetragonal and cubic crystals of KTa0.5Nb0.5O3 by the full potential linearized augmented plane wave method (FLAPW).Our calcul ated tetragonal optical spectra show three big peaks around 3,7 and 23 eV along a and b separately.Along c,there are three mainly peaks at 4,8,23 eV respectively,among which the one at 4 eV is sharp and high.Comparing optical pr operties in the tetragonal and cubic phass,we concluded that the tetragonal phas e has more anisotropic optical responses.
Influence of constant-current corona charging on electret state of porous PTFE film electret
Authors: Wu Yue-Hua  , Xia Zhong-Fu  , An Zhen-Lian  , Wang Fei-Peng  , Qiu Xun-Lin  ,   同济大学波尔固体物理研究所，上海 200092
Published: December 2020

The influence of constantcurrent and constantvoltage corona charging technique on the electret state of porous polytetrafluoroethylene(PTFE) film electret has been studied by constant current and constantvoltage corona charging at room temperature, is othermal surface potential decay, thermally stimulated discharge(TSD) and SEM(sc anning electron microscope), etc. Compared to the constantvoltage corona charging, the current through films is constant during constantcurrent charging, the r efore, the trapping possibility along the thickness direction of porous structur e increases and the charge density goes up, which improves the charge storage ab ilit y of the electret. However, the charges trapped in the dielectric surfaces of the interfaces with different depths along the thickness of the sample are externally stimulated during storage or application, their transport paths to the back electrode from the trapping positions are relatively shorter according to the hopping model of the charges, therefore the charge decay is accelerated and the charge sta bility is decreased.
The chemisorption of CO on a disordered binary alloy (NixCu1－x) and the mutual influence of chemisorption and surface segregation
Authors: Zhang Hui  , Zhang Guo-Ying  , Li Xing  , Liu Shi-Yang  ,   沈阳师范大学物理科学与技术学院，沈阳 110034
Published: December 2020

The atomic structural model of the NixCu1-x disordered binary alloy was set up for the cases with or without consideration of surface segrega tion by computer program ming.Then the model of the chemisorption of CO on the surface of the material wa s set up with a coverageθ=05. The electronic structure of CO chemisorpti on on the top and hollo w sites of the NixCu1-xdisordered binary alloy was calculated (considering and not considering the segregation).The calculated results show that (1) the CO ad sorbd at top site on the surface is stable and, (2) the chemisorp tion makes the surface density of states of the disordered binary alloy lowered, the ener gy ba nd widened and the localization of d orbital weakened and, (3) the chemisorpti on of CO on the surface restricts the surface segregation of Cu, then the mutual influence of chemisorption and multiplayer surface segregation is discussed at an electronic level.
Vertically aligned films for liquid crystals fabricated by monomer photo-crosslinking
Authors: Yu Tao  , Peng Zeng-Hui  , Ruan Sheng-Ping  , Xuan Li  ,   中国科学院激发态开放研究实验室，中国科学院长春光学精密机械与物理研究所,长春 130022
Published: December 2020

A new method to fabricate vertically aligned films for liquid crystals was proposed and studied experimentally. Photosensitive monomers of hexafluorobiphenol A dicinnamic esters were crosslinked by exposure under ultraviolet light. The obtained films could induce vertical alignment of liquid crystals. The process of the film making was very simple and did not need annealing at high temperatures. UV-visible spectra and polarized FT-IR spectra revealed that the photo-crosslinking reaction happened and reaction degree was rather high after the exposure under ultraviolet light. The stability of the aligned film could be kept to 120℃.
Exchange-coupling interaction and effective anisotropy of NdFeB nanocomposite permanent magnetic materials
Authors: Feng Wei-Cun  , Gao Ru-Wei  , Han Guang-Bing  , Zhu Ming-Gang  , Li Wei  ,   (1)钢铁研究总院功能材料研究所，北京 100081; (2)山东大学物理与微电子学院，济南 250100; (3)山东大学物理与微电子学院，济南 250100;钢铁研究总院功能材料研究所，北京 100081
Published: December 2020

Taking Nd2Fe14B/αFe as a typical sample and adopting the cubic grain model，we investigated the exchange-coupling interaction between different magnetic grains and the effective anisotropy of nanocomposite permanent materials in this paper . The effective anisotropy of nanocomposite permanent materials, Keff, is equal to statistical mean values of the effective anisotropy of magnetically soft and hard grains. Every grain's anisotropy is determined by the anisotropy constants of the coupled part at grain boundaries and the internal uncoupled part. The ca lculated results reveal that the distributions of soft and hard grain sizes influence th e effective anisotropy. When the sizes of magnetically soft and hard grains are identical, the effective anisotropy decreases with the reduction of grain size a nd hard phase component, and decreases rapidly while the grain size is less than 20nm. When the soft-grain sizes are of some definite values, Keff shows a maximum value with the variation of the hard-grain size. The hard-grain s izes corre spo nding to the maximum of Keffdecrease with the increase of soft phase components and the reduction of softgrain sizes. The grain size dependence ofKeffis bas ically similar to that of coercivity. The decrement of coercivity for nanoco m posite permanent materials is mainly due to the reduction of effective anisotrop y.
Study on the coercivity and step effect of mixed magnetic films by micromagnetism and Monte Carlo simulation
Authors: Weng Zhen-Zhen  , Feng Qian  , Huang Zhi-Gao  , Du You-Wei  ,   (1)福建师范大学物理与光电信息科技学院，福州 350007; (2)福建师范大学物理与光电信息科技学院，福州 350007;南京大学固体微结构国家重点实验室，南京 210093; (3)南京大学固体微结构国家重点实验室，南京 210093
Published: December 2020

The magnetic properties of ferromagnetically and antiferromagnetically mixed fi lms are simulated by micromagnetism method based on the principle of energy mini mum and Monte Carlo technology. The hysteresis loops, spin configurations, and the influences of exchange constant JAA, uniaxial anisotropy constant K, dipolar interaction constant Dand diluted ratio of ferromagnetic ato m X on the coercivity Hc at the ground states are studied systematical ly for the systems studied. A t the same time, the temperature dependence of the coercivity is calculated. The simulated results indicate that: (1) a steplike hysteresis is evidently observed in the mixed magnetic films, and the result calculated by a simple Ising model reveals that the steplike effect can be attributed to the different response of the clusters with different size and different diluted ratio of antiferromagn etic atom on the external field; (2) at the ground states, as 0.5≤X≤1.0,the value of Hc increases with increasing values ofK, JAA, but decreases with increasing value of D; (3) a peak exists in the HcX curves. These simulated resu lts explain the experimental facts about the granular films with antiferromagnetic coupling. The T dependence of the value ofHc for the films with diffe rent magnitude of X can be well described by the law of Tα. But the value of α has a complex variation with the change of X.
Structure phase transition and magnetic properties of nanocrystalline Zn0.6CoxFe2.4－xO4
Authors: Wang Jin-Zhi  , Fang Qing-Qing  ,   安徽大学物理系，合肥 230039
Published: December 2020

A series of nanocrystalline powders Zn06CoxFe24-xO4 ( x=0—030) was synthesized by the solgel technique. The structure and mag netic properties was investiga ted and analyzed through the xray diffraction (XRD) patterns and the vibrating sample magnetometer (VSM). The experimental results show that αFe2O3 tra nsitio nal phase appears in the temperature range from 550℃ to 800℃. Single-phase zinc-cobalt ferrites with a spinel structure are obtained when the temperature is beyond 800℃. With relatively higher values of the cobalt content x=0075 — 015, the specific saturation magnetization climbs up at first and then falls d o wn with the increase of the cobalt content. The coercive force strength Hc of Zn06CoxFe24-xO4 reaches its highest value 47520A/m when x=0075 at 1300℃. Hc increas es slowly with temperature near 1200℃ when x≥015 and remains in a flat s tate at 1200—1300℃ and moderate increase is obtained by increasing the x value. High specific saturation magnetization and coercive force can be obtained simultaneo usly when the cobalt content is near 010
Femtosecond spectral studies of electron spin injection and relaxation in AlGaAs / GaAs MQW
Authors: Sun Feng-Wei  , Deng Li  , Shou Qian  , Liu Lu-Ning  , Wen Jin-Hui  , Lai Tian-Shu  , Lin Wei-Zhu  ,   中山大学光电材料与技术国家重点实验室，物理系，广州 510275
Published: December 2020

The electron spin injection and relaxation in AlGaAs/GaAs multi quantum well(MQW) are studied with f emtosecond saturation absorption measurements. A electron spin relaxation time of 80±10ps is deduced. The relaxation mechanism is attributed to the randomizat ion of the local magnetic field arising from the spinorbit coupling.
Real-time measurement of the aerodynamic size of individual aerosol particles
Authors: Xia Zhu-Hong  , Fang Li  , Zheng Hai-Yang  , Hu Rui  , Zhang Yu-Ying  , Kong Xiang-He  , Gu Xue-Jun  , Zhu Yuan  , Zhang Wei-Jun  , Bao Jian  , Xiong Lu-Yuan  ,   (1)合肥科瑞电子有限责任公司,合肥 230031; (2)中国科学院安徽光学精密机械研究所环境光谱学实验室,合肥 230031; (3)中国科学院安徽光学精密机械研究所环境光谱学实验室,合肥 230031;东南大学物理系,南京 210096
Published: December 2020

This paper describes the recent development of an instrument designed to allow real-time measurement of the size and chemical composition of individual aerosol particles. We focused on the principle and features of aerodynamic sizing, then combine it with laser desorption ionization time-of-flight mass spectrometry, and the real-time measurement of wood smoke particles was performed.
Photonic band in quasi-fractal photonic crystal structure including idealized metal
Authors: Li Yan  , Zheng Rui-Sheng  , Feng Yu-Chun  , Niu Han-Ben  ,   (1)深圳大学光电子学研究所,广东省光电子器件与系统重点实验室，深圳 51 8060; (2)中国科学院西安光学精密机械研究所，西安 710068;深圳大学光电子学研究所，广东省光电子器件与系统重点实验室，深圳 518060; (3)中国科学院西安光学精密机械研究所，西安 710068;中国科学院研究生院，北京 100864
Published: December 2020

The photonic band of a set of quasi_fractal photonic crystals, which have similar structure and include idealized metal, is computed by finite-differ ence time_domain method. The result shows that there are photonic band gaps in t his kinds of quasi-fractal photonic crystals. It is found that, with increasing fractal series, the width of the photonic band gap is enlarged, the frequency of the photonic band totally trends to high frequency quickly, at the same time, the photonic band is quickly hauled to line and become a energy level.
Exciton tunnelling in ZnCdSe quantum well/CdSe quantum dots
Authors: Jin Hua  , Zhang Li-Gong  , Zheng Zhu-Hong  , Kong Xiang-Gui  , An Li-Nan  , Shen De-Zhen  ,   中国科学院长春光学精密机械与物理研究所 激发态物理重点实验室，长春 130033
Published: December 2020

Exciton tunneling through ZnSe barrier layer of various thicknesses is invest igated in a novel Zn072Cd028Se/CdSe coupled quantum well/quantum dots (QW/QDs) structure using photoluminescence spectra and nearresonant pumpprobe mea surements. Fast exciton tunneling from quantum well to quantum dots is observed by transient differential transmission. The tunneling time is 18ps, 44ps, 39 ps for barrier thickness of 10nm, 15nm, 20nm, respectively.
XPS study of fluorinated diamond-like carbon films prepared by reactive magnetron sputtering
Authors: Jiang Mei-Fu  , Ning Zhao-Yuan  ,   苏州大学物理科学与技术学院，苏州 215006
Published: December 2020

Fluorinated diamond_like carbon(F_DLC) films were prepared by radio frequency(RF) reactive magnetron sputtering with trifluoromethane (CHF3) and argon as source gases, and pure graphite as a targ et. The influence of source gas flow rate ratio on the film bonding configuration, sp2/sp3 hybrid ratios and optical band gap were investigated by Raman, Infrared transmission spectra, UV_visible spectra and XPS spectra. The results show that F-DLC films with high fluorine content, wide optical band gap and ultra-low diel ectric constant can be prepared by RF reactive magnetron sputtering technique in low input RF power (60W), high pressure (2.0Pa) and proper sour ce gas flow ratio (Ar/CHF3=2∶1).
3UCVD deposition SiO2 on SiC wafer and its C-V measurement
Authors: Tang Xiao-Yan  , Zhang Yi-Men  , Zhang He-Ming  , Zhang Yu-Ming  , Dai Xian-Ying  , Hu Hui-Yong  ,   西安电子科技大学 微电子研究所，西安 710071
Published: December 2020

The SiO2layer as a gate dielectric is grown on p_type 4H-SiC wafer by means of 3UCVD. Positive oxide charge density only has 1.6×1011cm-2, its result is superior to conventional thermally oxidized process. A new front tofront device with advantages over conventional test structure is used for high_frequ ency C-V measurement.
The structural optical and electrical properties of films prepared by screen print
Authors: Xu Jin-Bao  , Zheng Yu-Feng  , Li Jin  , Sun Yan-Fei  , Wu Rong  ,   新疆大学物理系，乌鲁木齐 830046
Published: December 2020

Thin films of iron pyrite(FeS2)have been prepared by screen print. X-ray diff raction (XRD) patterns were used to identify the nature of t he films. Special attention has been devoted to the structural parameters(cell and sulfur positional parameter), bond distances and angles, lattice constants. The procedure used in this study was the full profile refinement of x-ray powde r diffraction patterns using the Rietveld method. Here we report on the influnce of film thickness for resitivity, Hall mobility and optical energygap etc.
The synthesis and thermoelectric properties of double-atom-filled BamCenFeCo3Sb12 compounds
Authors: Luo Pai-Feng  , Tang Xin-Feng  , Li Han  , Liu Tao-Xiang  ,   武汉理工大学材料复合新技术国家重点实验室，武汉 430070
Published: December 2020

The single_phase double_atom_filled p_type BamCenFeCo3Sb12 c ompounds were synthesized using the solid_state reaction method and also the melt reac tion method. Thermoelectric properties of the p_type BamCenFeCo3Sb 12 compound were investigated, and the results indicated that the electri cal conductivity of the p_type BamCenFeCo3 Sb12 is intervenient between the electrical conductivities of single_atom _filled compounds BamFeCo3Sb12 and CenFeCo3Sb12.It d ecreased with increasing Ba and Ce fill ing fraction. With the same filling fraction, the lattice thermal conductivity o f BamCenFeCo3Sb12 is found to be smaller than that of Ba mFeCo3Sb12 and CenFeCo3Sb12.
Junction capacitance models of SiGe HBT
Authors: Lü Yi  , Zhang He-Ming  , Dai Xian-Ying  , Hu Hui-Yong  , Shu Bin  ,   西安电子科技大学微电子所，西安 710071
Published: December 2020

When SiGe HBT is in the case of normal operation, depleted approximation is not suited, and the influence of movable charge should be taken into account when c onsideri ng of their junction capacitance. Based on the analysis and study of the carr ier tr ansport of SiGe HBT, emitter junction capacitance model is developed by consider ing the carrier distribution, and the collector junction capacitance model is al so established for different current densities including base extending eff ect. The junction capacitance models are used to simulate frequency characteristics. The results of simulation show good agreements with the experimental data.
Quadratic stability and quadratic stabilization for singular system families
Authors: Wu Jian-Rong  ,   苏州科技学院应用数学系，苏州 215011
Published: December 2020

In this paper, the uncertainty of an uncertain singular system is described in the viewpoint of a system family. The concept of `generalized quadratic stable cone' is proposed. In terms of matrix inequalities, the necessary and sufficient conditions are derived, under which the considered uncertain system is generalized quadratic stable/stabilizable one.
Form invariance of mechanical systems with unilateral holonomic constraints
Authors: Zhang Yi  ,   苏州科技学院土木工程系，苏州 215011
Published: December 2020

In this paper, we study the form invariance of a mechanical system with unilateral holonomic constraints. According to the invariance of the form of the differential equation of motion under the infinitesimal transformations, we give the definition and criterion for the form invariance of mechanical systems with unilateral holonomic constraints, and establish the relation between the form invariance and Noether symmetry and Lie symmetry. In the end of the paper, an example is given to illustrate the application of the results.
An integral solution for the relative-rotation dynamic equation of a cylinder
Authors: Dong Quan-Lin  , Wang Kun  , Zhang Chun-Xi  , Liu Bin  ,   (1)北京航空航天大学光电技术研究所，北京 100083; (2)北京航空航天大学光电技术研究所，北京 100083;燕山大学仪器科学与工程系，秦皇岛 066004; (3)燕山大学仪器科学与工程系，秦皇岛 066004
Published: December 2020

For the relative rotation dynamic equation of the cylinder between random twain cross sections, we gain an analytic solution for the equation by using the coupling method. Due to the particularity of the equation, we gain an invertible matrix by utilizing the Jordan canonical. Thereby, we obtain an integral solution for the relative rotation dynamic equation of the cylinder. According to the reguirements in engineering applications, we give some analytic solutions of two types of load action, i.e.the impact and periodic types.
Multiple travelling wave solutions of two newly generalized Ito systems
Authors: Li Hua-Mie  , Lin Ji  , Xu You-Sheng  ,   浙江师范大学非线性物理研究所，金华 321004
Published: December 2020

By use of the extended mapping deformation method,many explicit and exact travelling wave solutions of the two newly generalized Ito systems are obtained which contain solitary wave solutions,trigonometric function solutions,Jacobian elliptic function solutions and rational solutions.
The entropy of Sen black hole and the Nernst theorem
Authors: Zhang Li-Chun  , Zhao Ren  ,   雁北师范学院物理系，大同 037000
Published: December 2020

By using the method of quantum statistics,we directly derive the partition functions of the bosonic field and fermionic field in the Sen black hole with an axial symmetry.Then via the improved brick-wall method and the membrane model,we calculate the entropies for the bosonic field and fermionic feld.We derive the entropy of the black hole which is not only related to the area of the outer horizon but also the function of the area of the inner horizon.In our results, there are no logarithmic divergent terms and left terms.There does not exist the question why the entropy of the scalar field or Dirac field outside the horizon is the entropy of the black hole.The influence of the spinning degeneracy of particles on the entropy of a black hole is studied.When the radiation temperature of the black hole approaches absolute zero,the entropy determined by the area of the inner and outer horizons also approaches zero.This satisfies the Nernst theorem.It can be taken as the Planck absolute entropy of a black hole.
Curvature vacuum correlations in quantum gravity
Authors: Shao Dan  , Shao Liang  , Shao Chang-Gui  , Chen Yi-Han  ,   (1)Department of Mathematical Sciences,Ibarati University,Mito 310-8512,Japan; (2)Department of Mathematical Sciences,Ibarati University,Mito 310-8512,Japan;湖北大学理论物理研究所，武汉 430062; (3)湖北大学理论物理研究所，武汉 430062
Published: December 2020

Under the flat Minkowski space-time background,in the harmonic and the arbitrary coordinate systems,we obtained the graviton free propagators in the n-dimensional general relativity (GR) and the high derivative gravity respectively,calculated the expressions of the leading terms of several two-point curvature vacuum correlation functions,and proved that they are zero in the GR,but in the high derivative gravity they are not zero.
The effects of charge on the potential energy function and energy levels for Cu2n±(n=0,1,2)
Authors: Mao Hua-Ping  , Wang Hong-Yan  , Tang Yong-Jian  , Zhu Zheng-He  , Zheng Sao-Tao  ,   (1)四川大学原子与分子物理所，成都 610065; (2)四川大学原子与分子物理所，成都 610065;重庆三峡学院化学系，万州 404000; (3)中国工程物理研究院，绵阳 621900
Published: December 2020

A theoretical study on Cu2n±(n=0,1,2) using density functional method (B3LYP/LANL2DZ) shows that Cu2, Cu+2,Cu-2,Cu2-2 are stable . Electronic ground states are 1Σg＋（Cu2），2Σg（Cu＋2），2Σu（Cu-2）and 1Σg（Cu22-）and their force constants and spectroscopic data have been worked out .The potential energy curves of Cu-2 and Cu2-2 have both minimum and maximum, which are the so-called“energy trapped”molecules，while Cu2+2 is unstable. At the same time, the effect of charge on the potential energy function and energy levels for Cu2n±(n=0,1,2) are discussed.
Long-range correlation in computer network
Authors: Liu Feng  , Shan Xiu-Ming  , Ren Yong  , Zhang Jun  , Ma Zheng-Xin  ,   (1)北京航天航空大学电子信息工程学院，北京 100083; (2)清华大学电子工程系，北京 100084
Published: December 2020

The long-range correlation of nodes in a computer network model is studied with the mean square fluctuation function of cumulative variable of queue lengths. It is shown that the queue lengths of the data packets of nodes change their temporal independence on or short-range correlation in the free flow state to long-range correlation in the critical and congested state with increasing system loading. The range of correlation enlarges and the collective long-range correlation emerges. In a free flow, the nodes are independent of each other or short-range correlative, and there exists a typical characteristic power exponent of 0.5. At the critical state, the nodes are long-range correlative, and there exists a typical characteristic power exponent bigger than 0.5. Moreover, the collective interaction becomes obvious and the power exponent decreases with enlarging network scale.
Chaos synchronization by using random parametric adaptive control method
Authors: Li Guo-Hui  , Xu De-Ming  , Zhou Shi-Ping  ,   (1)上海大学理学院，上海 200436; (2)上海大学通信与信息工程学院，上海 200072
Published: December 2020

Synchronization of two chaotic systems with different parameters using the random parametric adaptive control algorithm is proposed. Under the appropriate control law and feedback coefficient, the synchronization is achieved. To make this method realizable, Henon map is taken as a typical numerical example. The characteristic of random control period and flexible feedback coefficient shows its practicality.
Study on the physical meaning for generalized Mandelbrot-Julia sets based on the Langevin problem
Authors: Wang Xing-Yuan  , Meng Qing-Ye  ,   大连理工大学电子与信息工程学院，大连 116024
Published: December 2020

Based on a dynamics research of the typical Langevin problem, i.e., a moving charged particle under the continuous influence of a constant impulse in a double-well potential and a time-dependent magnetic field, using the stroboscopic sampling, we propose complex difference equations which can describe the change rule of particle's velocity. By selecting appropriate magnetic intensity and time intervals (sampling period), we reduce the difference equations to complex mapping which is used to construct the generalized M-J sets. Based on the particle's dynamics characteristic, we discussed the physical meaning of the generalized M-J sets. The authors found that: (1) The fractal structure of the generalized M-J sets may visually reflect the change rule of particle's velocity. (2) Whether the selected time intervals is significative determines whether the fractal structure of the generalized M-J sets has the continuity. (3) The evolution of the generalized M-J sets, i.e., the change rule of particle's velocity, depends on the different choices of the principal range of the phase angle. (4) If we change the choices of the magnetic intensity and time intervals, for example, choose a random fluctuant magnetic field, the generalized J sets may present the interior-filling structure feature, i.e., “explosion" phenomena appear in the closure of the particle's instable periodic orbits in the velocity space.
Numerical analysis of the signal modulation effect in bistable stochastic dynamical systems
Authors: Xiao Fang-Hong  , Yan Gui-Rong  , Han Yu-Hang  ,   (1)西安交通大学建筑工程与力学学院，西安 710049; (2)中国工程物理研究院，绵阳 610003
Published: December 2020

We study numerically the effect of signal modulating noise in bistable stochastic dynamical systems. By making a numerical analysis of the bistable stochastic dynamical systems, we find that the effect of an input sinusoidal signal is also a sinusoidal signal in the output, and the effect of the white noise is a Wiener process. When the system parameters are small enough, the coupling effect between the sinusoidal signal and the white noise can be largely weakened. Under this condition the noise can be largely reduced in the system output, and the effect of signal modulating noise can occur in the bistable stochastic dynamical systems.
Measurement and analysis of thermal properties of SiNx thin films
Authors: Yu Lei  , Yu Jian-Zu  , Wang Yong-Kun  ,   北京航空航天大学航空科学与工程学院,北京 100083
Published: December 2020

The thermal conductivity, emissivity, specific heat capacity and thermal diffusivity of SiNx thin films which are widely used in semiconductor and microelectronics MEMS are measured using a novel experimental method which combines the heater and the bolometer in one unit. The obtained reliable thermal properties are very useful for microelectronic circuits design and mask processing. The experimental data show that the thermal conductivity, emissivity and thermal diffusivity of SiNx thin films are much lower than those of the bulk and depend on the temperature and thickness of the thin films, and the size effect of SiNx thin films is notable. However, the specific heat capacity of SiNx thin films is almost the same as that of the bulk.
Preliminary research results for generation and application of high power ion beams on FLASH II accelerator
Authors: Yang Hai-Liang  , Qiu Ai-Ci  , Zhang Jia-Sheng  , He Xiao-Ping  , Sun Jian-Feng  , Peng Jian-Chang  , Tang Jun-Ping  , Ren Shu-Qing  , Ouyang Xiao-Ping  , Zhang Guo-Guang  , Huang Jian-Jun  , Yang Li  , Wang Hai-Yang  , Li Hong-Yu  , Li Jing-Ya  ,   (1)西安交通大学电气工程学院,西安 710049; (2)西北核技术研究所,西安69信箱10分箱 710024
Published: December 2020

Preliminary results for the generation and application of the high power ion beam(HPIB) on the FLASH Ⅱ accelerator are reported. The structure and principle of the pinch reflex ion beam diode are introduced. The equation of parapotential flow is corrected for the reduction of diode A-K gap due to the motion of cathode and anode plasma. The HPIB peak current of ～160kA is obtained with a peak energy of ～500keV. Experimental investigations of generating 6—7MeV quasi-monoenergetic pulsed γ-rays with high power ion(proton) beams striking 19F target are presented. In addition, the results of the thermal-mechanical effects on the material irradiated with HPIB, which are applied to the simulation of 1keV black body radiation x-rays, are also discussed.
Rotation of particles by using the beamwith orbital angular momentum
Authors: Gao Ming-Wei  , Gao Chun-Qing  , He Xiao-Yan  , Li Jia-Ze  , Wei Guang-Hui  ,   北京理工大学光电工程系,北京 100081
Published: December 2020

The twisted stigmatic beam with an orbital angular momentum was generated by transforming the Hermitian-Gaussian beam of a laser-diode-pumped solid-state laser through a rotated cylindrical lens system. By utilizing the orbital angular momentum of the generated beam, an “optical spanner” was designed and developed. By using the optical spanner micro-sized particles were trapped and rotated.
Dependence of the molecular ionic spectral intensity on the pressure of mother molecules
Authors: Gong Tian-Lin  , Yang Xiao-Hua  , Li Hong-Bing  , Han Liang-Kai  , Chen Yang-Qin  ,   (1)光谱学与波谱学教育部重点实验室,华东师范大学物理系,上海 200062; (2)光谱学与波谱学教育部重点实验室,华东师范大学物理系,上海 200062;南通师范学院物理系,南通 226007; (3)南通师范学院物理系,南通 226007
Published: December 2020

The dependence of molecular ionic spectral intensity on the pressure of mother molecules in velocity modulation spectroscopy was experimentally and theoretically studied. A new diagnosis of some plasma parameters, e.g. electric field, electron temperature and ionized coefficient, was proposed and carried out.
Theoretical calculation of ionization potential and term energy of the ground states 1s22s of lithium-like systems from Z=21 to 30
Authors: Ge Zi-Ming  , Wang Zhi-Wen  , Zhou Ya-Jun  ,   (1)华东理工大学理学院物理系，上海 200237; (2)吉林大学原子与分子物理研究所,长春 130023; (3)吉林大学原子与分子物理研究所,长春 130023;辽宁师范大学物理系，大连 110629
Published: December 2020

In the paper, the full-core plus correlation (FCPC) and the minimizing the expectation value of the Hamiltonian method is extended to calculate the non-relativistic energies and the wave functions of 1s22s states for the lithium-like systems from Z=21 to 30. The mass-polarization and the relativistic correction included the kinetic-energy correction, the Darwin term, the electron-electron contact term, and the orbit-orbit interaction are calculated perturbatively as first-order correction. The contribution from quantum electrodynamic (QED) is also included by using the effective nuclear charge formula. The ionization potential and term energies of the ground states 1s22s are given and compared with other's theoretical calculation and experimental results. It is shown that the FCPC methods are also effective to theoretical calculation of the ionic structure for high nuclear ion of lithium-like systems.
Constructing potential energy surface of tetratomic molecules using Lie algebra
Authors: Wang Xiao-Yan  , Ding Shi-Liang  ,   山东大学物理与微电子学院,济南 250100
Published: December 2020

Algebraic Hamiltonian of tetratomic molecules is classified using the coherent state.The potential energy surface is derived from the classical Hamiltonian. We proposed a new transformation for introducing the bond angles to the potential energy surface. We have calculated the dissociation energy and the force constants. These results are in good agreement with previous results.
Green's function method of light scattering from random surfaces compares with Kirchhoff's approximation
Authors: Liu Chun-Xiang  , Cheng Chuan-Fu  , Ren Xiao-Rong  , Liu Man  , Teng Shu-Yun  , Xu Zhi-Zhan  ,   (1)山东师范大学物理系,济南 250014; (2)中国科学院上海光学与精密机械研究所,上海 201800; (3)中国科学院上海光学与精密机械研究所,上海 201800;山东师范大学物理系,济南 250014; (4)中国科学院物理研究所和凝聚态物理中心光物理实验室,北京 100080;山东师范大学物理系,济南 250014
Published: December 2020

Starting from the Helmholtz Equation, we obtain the integral equations of the light field at the medium interfaces by use of Green's theorem. Then the integral equations are discretized into a linear equation set, from which the values of the light field and its derivatives at the interface can be numerically solved. We also obtain the expression for the transmissive light waves from the Green's-function integral in the case of Kirchhoff's approximation. By an analogy to the derivation process of the autocorrelation functions of speckles in Frauhofer plane, we propose the method for the generation of random self-affine fractal surfaces and Fourier transformation method for the numerical derivative of random surfaces. Then we study the accuracy of Kirchhoff's approximation in the scattering of light field from the random self-affine fractal surface. We find that the accuracy of Kirchhoff's approximation is relatively high when the root-mean-square roughness w is small. for random surfaces with the same value of w but smaller values of roughness exponent α, the Kirchhoff's approximation gives higher accuracy in the calculation of scattered light fields. We believe that the results of this paper would be of significance in understanding the validity range of the Kirchhoff's approximation when it is applied to light scattering from self-affine random surfaces.
Study of three-dimensional storage by parallel writing in PMMA with femtosecond laser pulses
Authors: Cheng Guang-Hua  , Wang Yi-Shan  , Liu Qin  , Zhao Wei  , Chen Guo-Fu  ,   中国科学院西安光学精密机械研究所瞬态光学技术国家重点实验室,西安  710068
Published: December 2020

Using a microlens array to focus an amplified femtosecond laser pulse inside a bulk PMMA(polymethyl methacrylate), optical breakdown occurs at each focus of the microlenses. By changing the positions of the foci,we realize the three-dimensional optical recording of high contrast bits at a speed of 20Mbit/s (with a 1kHz fs pulse laser ) in PMMA. Accordingly, modulation and readout of binary data have been presented. The diameter, focus length,and lens aberration in the microlenses are key factors which affect the recording speed and optical capacity based on this mechanism. Two kinds of effective ways to increase the capacity are discussed in this paper.
Teleporting superpositions of even and odd coherent states of a cavity field via the entangled state of a degenerate Λ-type atom interacting with the cavity field
Authors: Dai Hong-Yi  , Chen Ping-Xing  , Liang Lin-Mei  , Li Cheng-Zu  ,   国防科技大学理学院,长沙 410073
Published: December 2020

Based on the modified effective Hamiltonian for the system which is made up of a degenerate Λ-type three-level atom and a single-mode coherent state cavity field,the wave function of the system for the arbitrary initial states is derived by means of matrix forms. Through changing the interaction time,the entangled state of an atom-field is prepared. A feasible scheme is proposed to probabilistically teleport superpositions of even and odd coherent states of the cavity field by using the entangled state of a degenerate Λ-type three-level atom interacting with a coherent state cavity field of large amplitude under a far-off resonant condition. By performing Bell state measurement, the superpositions of even and odd coherent states of the cavity field can be successfully achieved with a total probability of 0.25.
Thermal background suppression in Rayleigh-type nondegenerate four-wave mixing based on field-correlation effects
Authors: Sun Jiang  , Jiang Qian  , Mi Xin  , Yu Zu-He  , Fu Pan-Ming  ,   中国科学院物理研究所光物理实验室,北京 100080
Published: December 2020

We apply the principle of field-correlation to the thermal background suppression of the Rayleigh-type nondegenerate four-wave mixing spectra,which have been employed for the measurement of ultrafast longitudinal time in the frequency-domain recently. Conditions,under which contributions from the thermal grating can be neglected,are given and numerical results that illustrate the validity of this method are presented.
Experimental research on gain characteristics and nonlinear effect of dispersion compensation Raman amplifiers
Authors: Chi Rong-Hua  , Lü Ke-Cheng  , Yun Peng  , Li Yi-Gang  , Dong Xiao-Yi  , Chen Wen-Zhao  , Yang Guang-Ming  , Liu Zhao-Bing  ,   (1)南开大学物理学院,天津 300071; (2)深圳市飞通光电股份有限公司,深圳  518057
Published: December 2020

Discrete dispersion compensation Raman amplifiers (DCRA) are recently used in dense wavelength division multiplexing (DWDM) systems for compensating for both dispersion and fiber loss simultaneously. In this paper,the gain spectrum,gain saturation and the effect of stimulated Brillouin scattering (SBS) of DCRA have been experimentally investigated.
Experimental study of a faster responsive effect of light induced refractive index change
Authors: Yang Li-Sen  , Liu Si-Min  , Zhang Guang-Yin  , Xu Jin-Jun  , Guo Ru  , Gao Yuan-Mei  , Huang Chun-Fu  , Lu Yi  , Wang Da-Yun  ,   (1)内蒙古师范大学物理系,呼和浩特 010022; (2)南开大学物理学院,天津 300071; (3)天津理工学院自动化系,天津 300191
Published: December 2020

We have observed an effect of light-induced refractive index change in LiNbO3∶Fe crystal sheet,which is different from the photorefractive effect. It has the characters of faster response (<0.1s),isotropy and function of information storage. We have also discussed the physical mechanism of the effect.
The influences of seed on stimulated Brillouin scattering pulse shape fidelity in seeded single-cell
Authors: He Wei-Ming  , Yang Jun  , Lü Yue-Lan  , Lü Zhi-Wei  ,   哈尔滨工业大学光电子技术研究所，哈尔滨 150001
Published: December 2020

To seed a Stokes pulse into the stimulated Brillouin seattering(SBS) generator, the induced SBS by this seeded Stokes pulse can make the SBS threshold reduced, and the best shape fidelity can be obtained. The influences of seed power on SBS pulse-shape fidelity in a seeded single-cell are investigated in theory and experiment.
Evolvement of filamentation of femtosecond laser pulses of a kHz repetition rate propagating in Air
Authors: Duan Zuo-Liang  , Chen Jian-Ping  , Fang Zong-Bao  , Wang Xing-Tao  , Li Ru-Xin  , Lin Li-Huang  , Xu Zhi-Zhan  ,   中国科学院上海光学精密机械研究所强光光学开放研究实验室，上海 201800
Published: December 2020

In this paper the evolvement of the filamentation of femtosecond laser pulses propagating in air is studied experimentally.We observed the variation of light intensity in the beam profile and the interaction of the filament with the distribution of light intensity in the forming of the plasma filament by using imaging.The experimental results show that the laser pulse propagating in air first forms two filaments and then merges into a single filament.The numerical simulation using the nonlinear Schrdinger equation coupled to a multiphoton ionization law appears to describe several experimental results quite well.
Supercontinuum generation in holey microstructure fibers by femtosecond laser pulses
Authors: Li Shu-Guang  , Ji Yu-Ling  , Zhou Gui-Yao  , Hou Lan-Tian  , Wang Qing-Yue  , Hu Ming-Lie  , Li Yan-Feng  , Wei Zhi-Yi  , Zhang Jun  , Liu Xiao-Dong  ,   (1)天津大学精密仪器与光电子工程学院教育部光电信息技术科学重点实验室，天津 300072; (2)燕山大学红外光纤与传感研究所，秦皇岛 066004; (3)中国科学院物理研究所光物理开放实验室，北京 100080
Published: December 2020

It Is reported that the supercontinuum spectrum can be generated in holey microstructure fibers by femtosecond laser pulses with a 800nm center wavelength. Broadband continua extending from 440 to 890nm are generated in holey microstructure fibers. Based on the theory of scalar approximation, the effective refractive index of the cladding and effective area for the fundamental space-filling mode and chromatic dispersion of fibers are calculated. It is found that the holey microstructure fibers have specifically the ability of controlling dispersion and waveguide property.The mechanism of supercontinuum generation in holey microstructure fibers is explicated preliminarily. The theoretic analysis is in good accodance with the experimental result.It is considered that supercontinuum broadband spectrum can be generated in holey microstructure fibers even if their cladding constitutes of random gas-line.
Relativistic energies of the singly excited and doubly excited Rydberg series in helium
Authors: Wu Xiao-Li  , Gou Bing-Cong  , Liu Yi-Dong  ,   北京理工大学理学院物理系，北京 100081
Published: December 2020

The Rayleigh-Ritz variational method is used with a multiconfiguration-interaction function to study the energies of singly excited and doubly excited Rydberg series in helium atom, including the mass polarization and relativistic corrections. The oscillator strengths, the transition rates, and the wavelengths are also calculated. The results are compared with other theoretical and experimental data in the literatures.
Studies on the amplified picosecond optical pulse by semiconductor light amplifiers using an improved model
Authors: Xia Guang-Qiong  , Wu Zheng-Mao  , Lin Gong-Ru  ,   (1)台湾交通大学光电工程研究所，新竹 300; (2)西南师范大学物理系，重庆 400715
Published: December 2020

After presenting an improved theoretical model that describes the dynamic process of optical pulses amplification by the semiconductor light amplifiers (SLAs), both the rising and falling time of amplified picosecond optical pulses by the SLAs have been investigated numerically. The results show that with the increase of the bias current of SLAs, the rising time will decrease and the falling time increase; the input pulse with a large peak power will accelerate the rising time shortening and the falling time lengthening; the gain compression has an obvious influence on the rising and falling time for several picosecond-width input pulses and gives approximately no effect on the input pulses in the tens of picosecond range; the gain asymmetry and shift strongly affect the rising and falling times.
Theory and experiment about in-fiber Bragg grating temperature sensing
Authors: Qiao Xue-Guang  , Jia Zhen-An  , Fu Hai-Wei  , Li Ming  , Zhou Hong  ,   (1)西安石油大学理学院，西安 710065; (2)西安石油大学理学院，西安 710065;西安交通大学电信学院，西安 710049
Published: December 2020

A theoretical method of in-fiber Bragg grating temperature sensing has been proposed. Based on a temperature sensing model of in-fiber Bragg gratings, it was deduced that the analytical formulae of first-order and second-order and effective linear sensitivity coefficients of in-fiber Bragg grating temperature sensing. The theoretical values of each sensitivity coefficient was calculated. Conic multinomial has been obtained by experiment. The results of theory and experiment were compared and analyzed. Furthermore, the influence of quartzose mechanical parameters on temperature sensing characters of in-fiber Bragg gratings and the application range of linear and nonlinear relations of reflected wavelength versus temperature were also discussed.
Mei symmetry,Noether symmetry and Lie symmetry of Hamiltonian canonical equations in a singular system
Authors: Luo Shao-Kai  ,   长沙大学数学力学与数学物理研究所，长沙 410003
Published: December 2020

The Mei symmetry,i.e.the form invariance,of the Hamiltonian canonical equations in a singular system is studied.The definition,the determining equations,the restriction equations and the additional restriction equations of Mei symmetry of the system are given.The relations among the Mei symmetry,the Noether symmetry and the Lie symmetry are studied,and the conserved quantities of the singular system are obtained.An example is given to illustrate the application of the result.