bluuebunny/crossref_metadata_2025 huggingface dataset:
A study on the soil heat flux along the Qinghai-Tibet railway based on the mult i-timescale analysis
Authors: Zhang Li-Jie  , Li Lei  , Shen Yong-Ping  ,   (1)中国科学院大气物理研究所大气边界层物理与大气化学国家重点实验室,北京  100029;V; (2)中国科学院寒区旱区环境与工程研究所冻土工程国家重点实验室,兰州  730000; (3)中国科学院寒区旱区环境与工程研究所冻土工程国家重点实验室,兰州  730000;V
Published: December 2020

By using soil temperature data from ANDUO, TTH and NODA station along the Qinghai-Tibet railway, the soil heat fluxes at 3 different depths in these 3 stat ions from September 1997 to August 1998 are calculated by use of integral method. Based on the multi-time scale analysis method, the time series of the soil heat fluxes is analyzed, and some important characters on the variation of soil he at fluxes against time and depth on different time scales are concluded.
Quasi-static particle simulation of short pulse laser-plasma interaction
Authors: Zhuo Hong-Bin  , Hu Qing-Feng  , Liu Jie  , Chi Li-Hua  , Zhang Wen-Yong  ,   国防科技大学计算机学院，长沙  410073
Published: December 2020

We have successfully developed the two-dimensional quasi-static particle simulation code MLPIC2D, which is an effective numerical tool to be used to describe the long-time plasma behavior under the action of an ultra high intensity short pulse laser. Simple physical modeling, numerical realization and code framework are discussed in detail. Three nonlinear phenomena of laser-plasma interaction:1) production of laser wake-fields, 2)relativistic focusing for short laser pulses, 3)quasi-static magnetic fields, are correctly simulated and analysed.
Energy structures of the elliptic cylindrical quantum dots
Authors: Hou Chun-Feng  , Guo Ru-Hai  ,   哈尔滨工业大学物理系，哈尔滨  150001
Published: December 2020

We have investigated the elliptic cylindrical quantum dot by adopting elliptic cylindrical coordinates and infinite-potential model, and presented the expressio ns for calculating the energy structures and wave-functions of the single electr on in the elliptic cylindrical quantum dot.
Quantum entropy of the general non-stationary black hole with charges
Authors: Liu Cheng-Zhou  ,   北京师范大学物理系，北京  100875;滨州学院物理系，滨州  256600
Published: December 2020

The quantum state number and free energy of the scalar field at the horizon of g eneral non-stationary black hole with charges are calculated and the result show s that the entropy of black hole is proportional to the event horizon area. This implies that the black hole entropy is just identical to the entropy of the qua ntum field on the event horizon. Taking into account the effect of the generaliz ed uncertainty principle on the black hole entropy and adopting the 2-D membrane model, the divergence in the brick-wall model is removed, without any cut-off， and the little mass approximations appear in the brick-wall model and the thin f ilm model are removed. Calculating the scalar field on the 2-D membrane outside horizon by using progression method we obtained some interesting results.
Entanglement of a Λ-type three-level atom with a single-mode field initially in the number state
Authors: Zhou Qing-Chun  , Zhu Shi-Ning  ,   (1)南京大学物理系，固体微结构国家重点实验室，南京  210093; (2)南京大学物理系，固体微结构国家重点实验室，南京  210093;华东船舶工业学院数理系，镇江  212003
Published: December 2020

The time evolution of entanglement and disentanglement between a Λ-type three-l evel atom and a single-mode field initially in the number state in an ideal cavi ty are investigated by considering von Neumann entropy of the optical field. Res ults indicate that entanglement of the system displays periodicity; the maximal degree of entanglement depends on the initial atomic state, the initial photon n umber and the ratio of detuning to the coupling constant, while the number of ti mes for maximal entanglement and disentanglement in a period is independent of t he initial photon number. The initial relative phase between the two lower state s have effects on the time evolution of field entropy, while the initial relativ e phases between the excited state and the ground states of the atom does not.
The dispersive characteristics of impurity bands in coupled-resonator optical waveguides of photonic crystals
Authors: Feng Li-Juan  , Jiang Hai-Tao  , Li Hong-Qiang  , Zhang Ye-Wen  , Chen Hong  ,   同济大学波耳固体物理研究所，上海  200092
Published: December 2020

We found that the dispersive properties of impurity bands in a coupled-resonator optical waveguide based on photonic crystals depend on the properties of the fields localized at the two neighboring defects instead of the distance of the defects. In fact, the seemingly anomalous dispersion of the impurity band in the first Brillouin zone is a result from band folding. After calculating the effective refractive index of the structure, we have verified that the impurity band has a normal dispersion.
Study on spatial resolution of polarized-modes coupling distributed fiber optic sensor
Authors: Zhou Xiao-Jun  , Du Dong  , Gong Jun-Jie  ,   电子科技大学宽带光纤传输与通信系统技术重点实验室，成都  610054
Published: December 2020

Phenomena of self-coherence and mutual-coherence of the distributed fiber optic sensor based on the principle of polarized-mode coupling are analyzed. The inter ference characteristics measured by experiment validate the theoretical analysis . The spatial resolution of the distributed fiber optic sensor is determined by the polarized dispersion coefficients of polarization-maintaining fiber and the spectral width of the light source. The spatial resolution of the polarized-mode s coupling distributed fiber optic sensor measured by experiment is 6cm.
Precisely fitting Thomson scattering spectrum in laser-produced plasmas
Authors: Wang Zhe-Bin  , Zhao Bin  , Zheng Jian  , Hu Guang-Yue  , Liu Wan-Dong  , Yu Chang-Xuan  , Jiang Xiao-Hua  , Li Wen-Hong  , Liu Shen-Ye  , Ding Yong-Kun  , Zheng Zhi-Jian  ,   (1)中国工程物理研究院激光聚变研究中心，绵阳  621900; (2)中国科学技术大学近代物理系，合肥  230027
Published: December 2020

Based on the collisionless, Maxewellian Thomson theory, a program is developed for carefully analyzing the influence of experimental set-up and plasma gradients and electron drifts on Thomson scattering spectrum. Calculations show that spectra resolution, collection angle, drift velocity and plasma gradient only have minor effects on diagnostics, so we can conveniently ignore these in fitting the spectrum. An important result is that signal-to-noise ratio can be enhanced by increasing the collection angle of the experimental system. The uncertainty of the scattering parameter can strongly affect the inferred plasma parameters when it is less than 3 This problem could be solved by choosing a smaller scattering angle or by accurately measuring the plasmas density.
A unified model for 1/f noise in n-channel and p-channel MOSFETs
Authors: Bao Jun-Lin  , Zhuang Yi-Qi  , Du Lei  , Li Wei-Hua  , Wan Chang-Xing  , Zhang Ping  ,   宽禁带半导体材料与器件教育部重点实验室，西安电子科技大学微电子研究所，西安  710071
Published: December 2020

1/f noise in n-channel and p-channel metal_oxide_semiconductor field effect tran sistors(MOSFETs) with different channel areas, are studied in theory and experim ent. Experimental results demonstrate that the 1/f noise magnitude in n-channel MOSFETs is ten times than that in p_channel MOSFETs, but both magnitudes are al l in inverse proportion to the power of effective gate voltage and its active ar ea, while they are in direct proportion to the power of drain voltage. Based on these experimental results, the mechanisms are discussed that the 1/f noise in M OSFETs is attributed to the random trapping/detrapping processes between channel and oxide traps near the SiO2_Si interface about several nanometers, which ca use fluctuations in both the number and the mobility of channel carriers. Based on these mechanisms, a unified 1/f noise model for MOSFETs is developed, includi ng tunneling and thermal activation through which traps communicate carriers wit h channel. Experimental results agree well with the developed model.
Effects of nano-scale particles in chemical mechanical polishing process
Authors: Zhang Chao-Hui  , Luo Jian-Bin  , Wen Shi-Zhu  ,   (1)北京交通大学机电学院，100044; (2)清华大学摩擦学国家重点实验室，100084
Published: December 2020

Chemical mechanical polishing(CMP) is a manufacturing process used to achieve th e high levels of global and local planarity required. Currently, the slurries us ed in CMP usually contain particles at nano scale to accelerate the material rem ove ratio (MRR) and to optimize the planarity. Micro polar theory will provide a feasible candidate to describe the rheology of these fluids. It will provide so me insights into the mechanism to solve the flow equation of CMP with the micro- polar effect considered. The effects of micro polarity on load and moments are s imulated and computation results are given. The results show that micro-polarity will give rise to an increase in load capacity to a certain extent by increasin g the equivalent viscosity of the slurries, through which the material removal c an be accelerated. The size-dependent feature can be seen since it becomes more prominent with low pitch height and low pad velocity. The effects of micro-polar ity on material removal rate in CMP process were experimentally investigated by altering the polarity of the slurries, which support the theoretical analysis.
Single electron capture process of ion-atom collisions by means of close-coupling method
Authors: Yang Wei  , Cai Xiao-Hong  , Yu De-Yang  ,   (1)中国科学院近代物理研究所，兰州  730000; (2)中国科学院近代物理研究所，兰州  730000;中国科学院研究生院，北京  100039
Published: December 2020

The basic idea of two-centre atomic orbital close coupling method is introduced in ion-atom collision process. We have found a systematic procedure to obtain th e parameter in close coupling calculation. We calculate the single electron capt ure cross sections for the collision of the multiply charged O6+ ion s with hydrogen atoms. The present calculations are in good agreement with exper imental data.
Energy spectra of ion beams from gas-puff Z-pinch plasma
Authors: Zou Xiao-Bing  , Wang Xin-Xin  , Luo Cheng-Mu  , Han Min  ,   清华大学电机工程系，北京  100084
Published: December 2020

The energy spectra of ion beams emitted from gas-puff Z-pinch plasma was experim entally studied with a compact Thomson spectrometer, which is composed of an inp ut window, deflecting electromagnetic fields,a rear pinhole, and a CR-39 track d etector. Ion beams were collimated by a front pinhole and the input window of Th omson spectrometer and deflected in the electromagnetic fields, and then they pa ssed through the rear pinhole to hit the CR-39 detector. Based on the detected p ictures of parabolas, we have calculated the energy spectra of ion beams and fou nd that the energy spectra move toward the direction of lower energy for a bad Z -pinch shot. A “bad Z-pinch shot" here means a shallower dip on the di/dt signal, which is the time derivative of Z-pinch current.
Spatio temporal evolution of electron beam instability in collisionless plasmas
Authors: Zheng Chun-Yang  , Liu Zhan-Jun  , Li Ji-Wei  , Zhang Ai-Qing  , Pei Wen-Bing  ,   (1)北京应用物理与计算数学研究所，北京  100088; (2)中国工程物理研究院研究生部，北京  100088
Published: December 2020

The spatio temporal evolution of electromagnetic (Weibel-type) and electrostati c (two-stream) instabilities of electron beams propagating in collisionle ss plasmas were investigated by using electromagnetic relativistic particl e-in-cell simulations. The onset and nonlinear saturation of Weibel instability , the emergence of beams and magnetic field reconnection were discussed. T he excitation of longitudinal electric field plays an important role for the stable propagation of electron beams, which can be destructed by the transverse modulation due to two-stream instability. These results may be important for understanding the static magnetic field generation and fast electron propagati on in fast ignition physics.
Measurement of metastable state densities and electron temperatures in an electron cyclotron resonance argon plasma
Authors: Chen Zhuo  , He Wei  , Pu Yi-Kang  ,   (1)清华大学工程物理系，北京  100084; (2)清华大学工程物理系，北京  100084;北京理工大学物理系，北京  100081
Published: December 2020

The number of metastable state densities obtained ranges from 1×1015to 4×1015 m-3 in the electron cyclotron resonance (ECR) argon plasma by measuring the optical absorption of the 8115 nm spectral line under the conditions of 02—08 Pa and 500—800 W. Taking into account the c ontribution of both the ground state and the 1s5 metastable state to the emiss ions, the electron temperature Te is measured by the ratio of emissio n lines. Results show that there are obvious differences compared with only considering t he metastable state densities.
Analysis of reflection high-energy electron diffraction pattern during SrTiO3 homoepitaxy
Authors: Wei Xian-Hua  , Zhang Ying  , Li Jin-Long  , Deng Xin-Wu  , Liu Xing-Zhao  , Jiang Shu-Wen  , Zhu Jun  , Li Yan-Rong  ,   电子科技大学,微电子与固体电子学院,成都  610054
Published: December 2020

SrTiO3 surface was monitored in-situ by reflection high-energy electron diffraction(RHEED) during annealing and homoepitaxial growth in laser molecular beam epitaxy(LMBE). By analyzing RHEED pattern, we show the oscillation behavior of in-plane lattice constant and full-width at half maximum (FWHM) of diffraction streaks; the former is due to the interface between the annealed reconstruction surface and the growing film, and the origin of the latter is related to the relaxation of 2D islands by their edges. In addition, the phase shift of RHEED intensity oscillation was observed, due to plasma influence on the incident electron beam.
Electron transport properties of the finite double-walled carbon nanotubes
Authors: Chen Jiang-Wei  , Yang Lin-Feng  ,   (1)南京大学物理系，南京  210093;南京炮兵学院，南京  211132; (2)南京大学物理系，南京  210093;中原工学院，郑州  450007
Published: December 2020

Based upon the Landauer formula,we have studied electron transport properties of finite incommensurate and commensurate double_walled carbon nanotubes(DWNTs).The results obtained show that the geometrical structures of the tube may produce significant effects on their electron transport properties:Electron transport of the incommensurate DWNTs may be either ballistic or non_ballistic,depending on the energy region.The commensurate DWNTs formed by the armchair tubes may displa y quick and slow oscillation;however,those formed by the zigzag tubes have no re gular slow oscillation.
Simulation of transmitting sound wave in one-dimensional easy-expanding medium
Authors: Han Ru-Qu  , Shi Qing-Fan  , Sun Gang  ,   (1)北京理工大学物理系，北京  100081; (2)北京理工大学物理系，北京  100081;中国科学院物理研究所，北京  100080; (3)中国科学院物理研究所，北京  100080
Published: December 2020

A new model of medium is established,in which the elastic modulus is bigger when the sound wave is in the compressed area,while it is smaller in the expanding area.The strong nonlinear coupling effect occurs when the compressed wave and the expanding wave exist in the same area.The calculated results show that the coupling of compressed wave and expanding wave can result in the expanding of the system,which is related to the relative difference between the expanding elastic modulus and compressing elastic modulus.In addition,the results obtained from the elastic modulus of non_continuum are the same as the limit case of continuous elastic modulus.
Pressure and temperature dependence of shear modulus and yield strength for aluminum, copper and tungsten under shock compression
Authors: Peng Jian-Xiang  , Jing Fu-Qian  , Wang Li-Li  , Li Da-Hong  ,   (1)宁波大学力学与材料科学研究中心，宁波  315211; (2)中国工程物理研究院流体物理研究所冲击波物理与爆轰波物理实验室，绵阳  621900
Published: December 2020

Experimental data of shear modulus and yield strength of shocked aluminum, copper and tungsten were analyzed systematically. Comparison between these data and t he results calculated by using SCG(Steinberg-Cochran-Guinan) constitutive model (J.Appl.Phys.51(3):1498) shows that shear modulus and yield strength have simila r dependence on pressure and temperature under conditions for aluminum below 50 GPa, copper below 100 GPa and tungsten below 200 GPa shock pressures. So the as sumptions in the SCG model,Y′pY0=G′pG0,Y′TY0=G′TG0, are approximately correct in these pressure ranges, and the SCG model can be used to describe the shear modulus and yield strength of these metals at high shock pr essure and high temperature.
Effects of the oxygen vacancy on NO adsorption at the TiO2 surface
Authors: Wang Yang  , Meng Liang  ,   (1)兰州交通大学光电技术与智能控制教育部重点实验室，兰州  730070; (2)浙江大学金属材料研究所,杭州  310027
Published: December 2020

The desorption spectrum of NO adsorbed on the surface of TiO2 powder was determined by temperature programmed desorption. The molecular orbital theory was u tilized to investigate the crystal cluster model of NO adsorbed on TiO2 and th e change of band gap in the adsorption process. The results indicate that there exist two peak temperatures, 450 and 980K, as N2 desorption followed by the NO adsorption on TiO2 The intensity of N2 desorption decre ases if the TiO2 powder is pretreated in an O2 atmosphere. The nitrogen atoms of the adsorbed NO gas recombine into N2 for desorption while oxygen atoms occupy th e oxygen vacancies in the TiO2 surface. The calculation analysis from the mole cular orb ital theory supports the deduction that the existence of oxygen vacancy on TiO2(110) surface offers a suitable condition of crystal surface for NO ad sorption.
Capacitive humidity-sensing properties of Si-NPA and Fe3O4/Si-NPA
Authors: Wang Hai-Yan  , Li Xin-Jian  ,   郑州大学物理系，材料物理教育部重点实验室,郑州  450052
Published: December 2020

The preparation of silicon nanoporous pillar array (Si-NPA) and Fe3O 4 coated Si-NPA (Fe3O4/Si-NPA) is presented. The morphologies and microstructures of the two kinds of thin films were characterized and their corresponding capacit ive humidity sensing properties investigated. It was shown that both Si-NPA and Fe3O4/Si-NPA are typical micron/nanometer structural compo site systems. When the relative humidity increased from 11% to 95%, the capacitances reached 1500% and 5500% of their initial values measured with 100 Hz signal frequency, and 800% and 12000% measured with 1000 Hz signal frequency, for Si-NPA and Fe3O4/S i-NPA, respectively. At the same time, both of the two thin films exhibited quic k response speed, the response times in the humidity-increment and humidity-decr ement processes were determined to be 15 s and 5 s for Si-NPA, and 20 s and 15 s for Fe3O4/Si-NPA, respectively. These excellent humidity sensing properties of Si-NPA and Fe3O4/Si-NPA are explained based on thei r corresponding morph ological and structural properties. Our experiments strongly indicated that Si-N PA is an ideal thin film both for direct humidity sensing and as a substrate for growing composite humidity sensing materials.
Airy function and transfer matrix method in the study of quasi-bound levels of biased multi-barrier quantum structures
Authors: Wang Hong-Mei  , Zhang Ya-Fei  ,   上海交通大学薄膜和微细技术教育部重点实验室,微纳米科学技术研究院，上海  20003 0
Published: December 2020

The quasi-bound levels in biased/unbiased double/triple-barrier quantum structures have been exactly calculated based on the solution of the one_dimensional (1D) time-independent Schrdinger equation using Airy function and transfer matrix method, which is easily extended to multi-barrier quantum structures; furthermo re, the dependence of the quasi-bound levels on the effective masses and bias in biased/unbiased double/triple-barrier quantum structures has also been investig ated. In addition, errors of Airy function and transfer matrix method in the stu dy of quasi-bound levels of biased multi-barrier quantum structures in other let ters have been pointed out and verified.
Simulations of the structure characteristic of diamond-like carbon films formed by ion-beam-assisted deposition
Authors: Li Zhi-Jie  , Pan Zheng-Ying  , Zhu Jing  , Wei Qi  , Wang Yue-Xia  , Zang Liang-Kun  , Zhou Liang  , Liu Ti-Jiang  ,   (1)复旦大学现代物理研究所，上海  200433; (2)复旦大学现代物理研究所，上海  200433;内蒙古民族大学物理与机电学院，通辽  028043
Published: December 2020

Molecular dynamics (MD) simulation was used to study the growth process of dia mond_like carbon (DLC) films synthesized via ion_beam_assisted deposition (IBAD ). The C2 molecules and Ar ions were selected as deposition and assis tance pr ojectiles, respectively. The influence of the impact energy of Ar as well as the assistance/deposition atomic ratio (Ar/C), on the film structure was investiga ted. The transient mobility and the migration of C adatoms caused by Ar impact were studied. Our results indicate that the impact-induced high recoil energy a nd displacement of deposited C atoms play a leading role in the growth of DLC f ilms. This can be attributed to the incident energy and momentum of assistance Ar. Our results agree well with the experimental observation. Furthermore, it e xplains the growth mechanism partly.
Low frequency noise study on short wavelength HgCdTe photodiodes
Authors: Huang Yang-Cheng  , Liu Da-Fu  , Liang Jin-Sui  , Gong Hai-Mei  ,   (1)中国科学院上海技术物理研究所传感技术国家重点实验室，上海  2000832; (2)中国科学院上海技术物理研究所传感技术国家重点实验室，上海  2000832;中国科学院研究生院，北京  100039
Published: December 2020

The current-voltage characteristics and the low frequency noise measured at 255 —293K are reported. The figures of merit increase from 45×103 t o 7×104Ωcm2 as the temperatures decreases. At low fre quencies the noise mainly cons ists of flicker noise and generation recombination (g-r) noise, while at high fr equencies thermal noise is the dominant component. The flicker noise current is proportional to the detector current at reverse bias, and the Hooge parameter αH of the device is (3—7)×10-4. In addition, the fluc tuation time co nstant τ of the g-r noise is extracted by fitting the curve of the low_freq uency noise. Therefore, the trap thermal activation energy of the deep level is obtained from the relation between τ and temperature.
Analysis of the mechanism and characteristic for the transparent anode in a gate commutated thyristor
Authors: Wang Cai-Lin  , Gao Yong  , Ma Li  , Zhang Chang-Li  , Kim Eundong  , Kim Sangcheol  ,   (1)韩国电气研究院电力半导体研究室,韩国  641-600; (2)西安理工大学电子工程系，西安  710048
Published: December 2020

The mechanism of the transparent anode in gate commutated thyristors (GCT) was i nvestigated by analyzing its current transportation theoretically, and the expre ssion of the electron current density at the transparent anode is deduced. The s imulation result of the CCT's switching characteristic validates the correctnes s of the mechanism analysis for the transparent anode. In addition, the characte ristic of the transparent anode in GCT devices was analyzed by compared with gen eral anode in GTO devices. The results show that the transparent anode can impro ve effectively the switching characteristic and reduce the switching loss, and t he transparent anode with an additional n buffer layer used in GCT can make the trade off among the on-state characteristic,blocking characteristic and switchin g characteristics,and improve further the characteristics of GCT.The conclusions are validated by the experiment results.
AMPS modeling of light J-V characteristics of a-Si based solar cells
Authors: Hu Zhi-Hua  , Liao Xian-Bo  , Diao Hong-Wei  , Xia Chao-Feng  , Xu Ling  , Zeng Xiang-Bo  , Hao Hui-Ying  , Kong Guang-Lin  ,   (1)云南师范大学能源与环境科学学院，昆明  650092; (2)中国科学院半导体研究所，北京  100083; (3)中国科学院半导体研究所，北京  100083;云南师范大学能源与环境科学学院，昆明  650092
Published: December 2020

AMPS (Analysis of microelectronic and photonic structures) mode,which was developed by Pennsylvania State University,has been used to module the light J_V c haracteristics of a_Si solar cells with a structure of TCO/p_a_SiC:H/i_a_Si:H/n_ a_Si:H/metal.The effects of valence band offset and contact barriers at p/i and TOC/p,n/metal interfaces on the light J_V characteristics have been examined .The modeling has qualitatively categorized and explained the non_ideal J_V behaviors (rollover,crossover,Voc shift,and rollunder) observed in a_Si based so lar cells.
Flux jumps in textured (Nd0.33Eu0.33Gd0.33)Ba2Cu3O7－δ superconductor with high content Gd-211 phase
Authors: Chi Chang-Yun  , Zhang Jin-Cang  , Li Ling-Wei  , Liu Fen  , Li Wen-Feng  , Jing Chao  , Cao Shi-Xun  , Muralidhar Miryala  , Yao Xin  ,   (1)Superconductivity Research Laboratory (SRL),ISTEC,Japan; (2)上海大学物理系，上海  200436; (3)上海交通大学物理系，上海  200436
Published: December 2020

Flux jumps behavior in textured (Nd0.33Eu0.33Gd0.33)Ba2Cu3O7-δ （with high content of Gd-21 1 phase） have been studied. With the magnetic field parallel to the c axis, partial flux jumps have been obser ved in the temperature range 2—3K, and there were no jumps found above 5K. When ab plane is parallel to the field direction, no flux jumps have been observ ed in the whole temperature range (from 2K to Tc). The anisotropi c flux instability may be due to the anisotropic pinning force and geometrical demagnet ization factor. As the temperature increases,the number of flux jumps is decreas ed, and the third quadrant of M(H) curve is the most flux instability quadra nt. Finally we have studied the magnetic field sweep rate dependence of flux jum p, and discussed the influence of flux creep on flux jump.
Effect of the insulating layer on the differential conductance in the normal metal/insulator/s-wave superconductor tunnel junctions
Authors: Wei Jian-Wen  , Dong Zheng-Chao  ,   淮阴师范学院物理系,淮安  223001
Published: December 2020

Making use of the square-potential barrier to describe the influence of the insulating layer on the quasi-particle transport in normal metal/insulator/superconductor (NIS) tunnel junctions, we calculate the quasi-particle transport coeffic ients and the differential conductance using the Bogoliubov-de Gennes（BdG）equa tion and Blonder-Tinkham-Klapwijk(BTK) theory. It is found that the change of th e differential conductance with insulating layer thickness takes the form of the oscillation and attenuation, the period of oscillation and the speed of attenua tion depend strongly on the potential magnitude of the insulating layer and the bias value, the height of the conductance peaks and their positions are related to the insulating layer thickness intimately. It is shown that the tunneling spe ctra are different from those described by the δ-potential.
Microwave measurements of the MgB2 thin film
Authors: Wang Shu-Fang  , Jin B. B.  , Liu Zhen  , Zhou Yue-Liang  , Chen Zheng-Hao  , Lü Hui-Bin  , Cheng Bo-Lin  , Yang Guo-Zhen  ,   (1)Forchungszentrum Julich,Institute of Thin Films and Interfaces,D-52425 Julich,Germany; (2)河北大学物理科学与技术学院，保定  071002;中国科学院物理研究所北京凝聚态物理国家实验室,北京  100080; (3)中国科学院物理研究所北京凝聚态物理国家实验室,北京  100080
Published: December 2020

We have measured the microwave surface resistance Rs, the magnetic fi eld penetration depth λ(0) and the energy gap Δ(0) of MgB2 thin film s using the dielectric resonator technique. The c_axis textured sample, with superconducting transition temperature of 38K and transition width of 01K, w as prepared on MgO(111) substrates by the chemical vapor deposition method. The Rs value of the MgB2 thin film at 10K was found to be as low as 100 μΩ, which is comparable to that of a high_quality high_temperature thin film o f YBCO. BCS fits of the temperature dependence of Δλ of the MgB2 t hin film gave λ(0)=102nm and Δ(0)=113kTc.
Quantum transport of four-terminal nano-molecular bridge
Authors: Wang Li-Guang  , Li Yong  , Yu Ding-Wen  , Wang Jun  ,   (1)江南大学理学院,无锡  214064; (2)清华大学精密仪器与机械学系，北京  100084
Published: December 2020

The characteristics of quantum transmission through a four-terminal nano-molecular bridge are investigated theoretically by using tight-binding approach, based on the Green's function with only a π orbital per carbon atom at the site. The transmission probabilities of the electrons transported through the molecular bridge to every terminal are obtained. The electronic current distributions inside the molecular bridge are calculated and shown in graphical analogy by the current density method and Fisher-Lee formulism at the energy points E=±12 and E=±149 where transmission probabilities show peaks, the maximum bond currents are also presented. It is found that the loop currents in molecules are induced by the phase difference of the molecular orbitals.
Anisotropic magnetoresistance effect in spin valve multilayers
Authors: Jiang Hong-Wei  , Wang Ai-Ling  , Zheng Wu  ,   首都师范大学物理系，北京  100037
Published: December 2020

Planar Hall effect(PHE) in Ta(8nm)/NiFe(7nm)/Cu(2.4nm)/NiFe(4.4nm)/FeMn(14nm)/Ta(6nm) spin valve multilayer have been measured in magnetic fields rotating in the film plane. A “mixed” effect of the free and pinned layers on anisotropic magnetoresistance (AMR) has been obtserved. The result shows that the PHE can give more information about the magnetic configurations of the spin valve multilayers than the usual MR measurements.
Effects of atomic defects of α-Al2O3(0001) on ZnO adsorption
Authors: Yang Chun  , Li Yan-Rong  , Yan Qi-Li  , Liu Yong-Hua  ,   (1)电子科技大学微电子与固体电子学院，成都  610054; (2)四川师范大学固体物理研究所，成都  610068; (3)四川师范大学数学与软件科学学院，成都  610068; (4)中国物理工程研究院化工材料研究所，绵阳  621900
Published: December 2020

The Al and O atomic vacancies on α-Al2O3(0001) surface an d the adsorption o f ZnO are calculated theoretically by using a plane wave ultrasoft pseudo-potent ial method based on density functional theory. The electron localization functio n(ELF) shows the electronic density changes at the atomic vacancies. There is an obvious absence of electronic areas where the vacancies of Al have the dangling bonds of oxygen, which are favourable for the adsorption of Zn atoms. In contra st, at the vacancies of O, there are more electron distribution(ELF:005—03) , forming lone electron pairs which are profitably available to combine O atoms or O2- ions. Through the dynamics calculation, we find that surface d efect s can significantly strengthen particle adsorption, and the vacancies are filled by adatoms(Al or O), with the adsorption energy much higher than the case of th e adsorption on a perfect surface. The surface Al-vacancies where the ZnO adsorp tion clearly breaks the hexagonal symmetry of oxygen on the α-Al2O3(0001) s urface because of the formation of the O double bonds, which apparently weakens the reaction diffusivity of O, and has a further negative impact on the regular ZnO films formation. Accordingly, more defects and dislocations in films growth might be produced. Contrarily, the O-vacancies on the α-Al2O3(0001) surface , the chemisorption and dissociation of ZnO do not have an effect on the surface hexagonal symmetry.
Investigation of spectral properties and thermal stability of Er3+/Yb3+ co-doped tungsten-tellurite glasses
Authors: Shen Xiang  , Nie Qiu-Hua  , Xu Tie-Feng  , Gao Yuan  ,   宁波大学信息科学与工程学院，宁波  315211
Published: December 2020

Er3+/Yb3+ co-doped tungsten-tellurite glasses, 65TeO2 -25WO3-10RmOn(RmOn= PbO,BaO), (65+x) TeO2-(25-x)WO3- 10La2O3(x=0,5,10),(60+x)TeO2-(30-x)WO3-10Bi2O3(x=0,5,10) have been prepared. The thermal stability and spectral properties, such as absorption spec tra, emission spectra and lifetimes of the 4I13/2 level of Er3+ were investigated. Results obtained show that tungsten-telluri te glasses have good thermal stability. All the glass samples except the Bi2O3-containing g lasses show no onset temperature of crystallization (Tx), indicating that they are stable for fiber drawing. Three intensity parameters Ωt(t= 2,4, 6) were calculated by Judd-Ofelt theory. It is shown that Ω2 is domi nated b y the covalency between the Er3+ and O2-, the effect of as ymmetry in the local structures around the Er3+ ions on Ω2 can be neglected. The full width at half maximum (FWHM=71—77 nm) of the 4I 13/2→ 4I15/2 emission and lifetimes of 4I 13/2 level(τm= 3—3.4 ms) of Er3+ ions were measured. The emission cross-section ( σpeak=068—103×10-20 cm2) of the 4I13/2→4I15/2 transitio n of Er3+ ions were calculated according to the McCum ber the ory. The FWHM and emission cross-section of Er3+ ions at 1.5 μm ba nd in d ifferent glass hosts were compared. The results show that tungsten-tellurite gla ss will be the promising host material for 1.5 μm broadband amplification.
Optical properties of alloy states in GaNxAs1－x(x<0.01)
Authors: Luo Xiang-Dong  , Sun Bing-Hua  , Xu Zhong-Ying  ,   (1)南通大学理学院,南通  226007; (2)南通大学理学院,南通  226007;中国科学院半导体研究所超晶格国家重点实验室,北京  100083; (3)中国科学院半导体研究所超晶格国家重点实验室,北京  100083
Published: December 2020

A set of GaNxAs1-x samples with a small content of nit rogen (N)( xAs1-x, which was extremely different from the N_related i mpurity states. At the same time, PR spectra were also studied in this work.
The properties of the as-sputtered ZnO films under different deposition parameters after sulfidation
Authors: Zhang Ren-Gang  , Wang Bao-Yi  , Zhang Hui  , Ma Chuang-Xin  , Wei Long  ,   中国科学院高能物理研究所核分析技术重点实验室,北京  100049
Published: December 2020

ZnS films are produced on the glass and quartz substrates by sulfidation of the as-sputtered ZnO films in the H２S-H２-N2 mixtu re. The properties of the f ilms are characterized by using the XRD, SEM and transmission measurements. The results show that the ZnS films with a hexagonol structure have a (002) preferre d orientation. The crystallinity and optical transmission spectra of the ZnS fil ms are related to working pressure and Ar/O２ ratio during the deposi tion of t he ZnO films. At the pressure >1Pa, the thickness of the ZnS films is very sma ll, while at the pressure ２ ratio higher or lower than 4∶1 will leads to the poor crystalline ZnS films. Also it is found that the ZnS films formed from the unannealed ZnO films almost have the same grain size as those formed from th e in-air annealed ZnO films, due to the high (002) preferred orientation during the growth of the ZnS films.
Study on preparation and properties of ZnO nano-bulk materials
Authors: Qin Xiu-Juan  , Shao Guang-Jie  , Liu Ri-Ping  , Wang Wen-Kui  ,   (1)燕山大学亚稳材料科学与技术重点实验室,秦皇岛  066004; (2)燕山大学亚稳材料科学与技术重点实验室,秦皇岛  066004;中国科学院物理研究所,北京  100080
Published: December 2020

Nano_scale ZnO green disks are prepared by continuous compaction process. Relation between green density, sintering time, densification temperature and compaction method is examined. Microstructure of the samples is characterized by an XL30S_FEG field esmission scanning electron microscopy. Hardness of the ZnO nano_bulk is measured as a function of sintering temperature. The results show that gree n density is increased by 56%, sintering time is decreased by 3h and densifica tion temperature is decreased by 200℃ after the continuous compaction process. Distributions of density and grain size within the sintered body are homogeneous through examination of the XL30S_FEG field esmission scanning electron microsco py. Hardness values imply that the relation between micro_hardness and sintering temperature is not monotonic, but first increasing then decreasing with increas ing sintering temperature in the ZnO nano_bulk. The grain size at the inflexion point is about 50—60nm.
The life prediction for materials under the corrosion of seawater
Authors: Liu Jing-Jing  , Sun Jun-Jun  , Hu Hai-Yun  , Xing Xiu-San  ,   北京理工大学物理系,北京  100081
Published: December 2020

A formula of fatigue life for materials in seawater is derived based on the non-equilibrium statistical theory of fatigue. As an example, the results of soft steel under the ocean corrosive circumstance are compared with that when they ar e free of corrosion.
An approach to obtain the photofragment translational energy distribution from time-of-flight profile
Authors: Shi Yong  , Li Qi-Feng  , Wang Hua  , Dai Jing-Hua  , Liu Shi-Lin  , Ma Xing-Xiao  ,   中国科学院选键化学开放研究实验室,中国科学技术大学化学物理系,合肥  230026
Published: December 2020

At the magic angle, the time_of_flight mass_spectrometer (TOF-MS) profile depends only on the translational energy distribution of photofragment, and is indep endent of the angle distribution of recoil momentum, therefore, the translationa l energy distribution is usually determined by fitting the measured TOF-MS profi le. Different from the above procedure, we take another approach in the present work. According to this method, by measuring three widths at half maximum (t 1/2), one-fourth maximum (t1/4) and three-fourth m aximum (t 3/4) of the TOF-MS profile, the averaged translational energy, th e width of translational energy distribution, as well as the width of instrumental func tion can be determined from numeric tables or mathematical expressions. In this method, both the translational energy distribution and the instrumental function are described by Gaussian functions.
Large area deposition of homogeneous Ag nanoparticles on polymeric surface and their applications
Authors: Xie Jiang  , Wen Jian-Zhong  , Wang Guo-Ping  , Wang Jian-Bo  ,   (1)武汉大学物理科学与技术学院，武汉  430072; (2)武汉大学物理科学与技术学院，武汉  430072;武汉大学电镜中心，武汉  430072
Published: December 2020

Silver nanoparticles with homogeneous size and density were deposited on the surface of a cellulose triacetate film through chemical dipping and photoreduction. UV-VIS absorption spectra and high resolution transmission electron microscopy (HRTEM) show that spherical silver nanoparticles with 2—5nm diameter were formed effectively at room temperature by properly modulating the concentration. By contact copying technique, holographic gratings were constructed with metallic nanoparticles embedded in the polymer film.
A study on the realization of radio frequency energy AC/DC charge pump based on MOS FET
Authors: Yao Yuan  , Shi Yin  ,   中国科学院半导体研究所人工神经网络实验室,北京  100083
Published: December 2020

This paper presents a novel efficient charge pump composed of low Vth metal_oxide_semiconductor (MOS) field effect transistors (FET) in the course of realizing radio frequency (RF) energy AC/DC conversion. The novel structure eliminates tho se defects caused by typical Schottky_diode charge pumps, which are dependent on specific processes and inconsistent in quality between different product batche s. Our analyses indicate that an easy_fabricated, stable and efficient RF energy AC/DC charge pump can be conveniently implemented through reasonably configurin g the MOS transistor aspect ratio, and other design parameters such as capacit ance, multiplying stages to meet various demands on performance.
A method to estimate the temperature coefficient for shear modulus
Authors: Hua Jing-Song  , Jing Fu-Qian  , Tan Hua  , Zhuo Xian-Ming  ,   中国工程物理研究院流体物理研究所冲击波物理与爆轰物理重点实验室,绵阳  621900
Published: December 2020

This article put forward a method to calculate the temperature coefficient for shear modulus(G′T) by means of theoreticial calculation and dynamic experiments. Firstly,introduce a calculation data G(PS), then combine with dynamic experimental data G(PH) to obtain G′T. Taking tungsten alloy as an example, the results show that G′T varies with pressure and temperature at the beginning, but at high pressure and high temperature, it is almost a constant of -004Gpa/℃ for tungsten alloy. This also verifies the assumption in Steinberg constitutive model that G′ T should be a constant. When we applied this constant to calculate the corrected shear modulus under shock compression, the calculated results are in accordance with the experimental data.
Symmetries of Lagrange system subjected to gyroscopic forces
Authors: Wu Hui-Bin  , Mei Feng-Xiang  ,   北京理工大学理学院，北京  100081
Published: December 2020

The Noether symmetry and Lie symmetry of the Lagrange system subjected to gyroscopic forces are studied. The condition that the system, under gyroscopic forces , can keep its Noether symmetry and Noether conserved quantity is given. And the condition that the system subjected to gyroscopic forces can keep its Lie symme try and Hojman conserved quantity is also given. Finally, two examples are given to illustrate the application of the results.
The generalized Hojman’s theorem
Authors: Zhang Hong-Bin  , Chen Li-Qun  , Liu Rong-Wan  , Gu Shu-Long  ,   (1)安徽省巢湖学院物理系，巢湖  238000; (2)上海大学上海市应用数学和力学研究所，上海  200072; (3)上海大学上海市应用数学和力学研究所，上海  200072;安徽省巢湖学院物理系，巢湖  238000; (4)上海大学上海市应用数学和力学研究所，上海  200072;广东省韶关大学物理系，韶关  512005
Published: December 2020

A new conservation theorem is studied, the conserved quantity is only constructe d in terms of the infinitesimal generators τ(t,q,q·) and ξs( t,q,q· ) of Lie symmetry of the dynamical equations. Three special cases are discussed, where the Hojman conserved quantity can be deduced as a corollary of this gener al conservation theorem at τ(t,q,q·)=0, and the Lutzky conserved quantity can be derived by using this general conservation theorem at τ=τ(t,q) and ξs=ξs(t,q).Moreover, a condition is presented to exc lude trivial conse rved quantities. Finally, two examples to illustrate the application of the resu lts are given.
Influence of Al content on Zener relaxation in Fe-Al alloys
Authors: Zhou Zheng-Cun  , Han Fu-Sheng  ,   (1)苏州市职业大学,苏州  215011; (2)中国科学院固体物理研究所内耗与固体缺陷开放研究实验室,合肥  230031
Published: December 2020

The effect of Al content on the Zener relaxation peak in annealed Fe-Al alloys has been investigated using a computer-controlled automatic inverted torsion pendulum through free-decay and forced vibration method. It has been shown that alloys with medium Al contents show strong relaxation while lower or higher Al content leads to relatively weak Zener relaxation peak. The relaxation in Fe-Al alloys originates from the next-nearest-neighbor atom-pairs and their interaction instead of the nearest-neighbor atom-pairs. The latter may not produce the Zener relaxation because of the ordered-structure formed, which suppresses Zener relaxation.
The indirect matching solution for a class of shock problems
Authors: Wu Qin-Kuan  ,   南京工程学院基础部  南京  210013
Published: December 2020

The shock wave problems for a class of the nonlinear singularly perturbed equations is studied. Using indirect matching method, the shock solutions of shock wave in an interval are constructed.
Extended projective Riccati equations method and its application
Authors: Yong Xue-Lin  , Zhang Hong-Qing  ,   大连理工大学应用数学系，大连  116024
Published: December 2020

The projective Riccati equations method is extended and applied to find new exac t solutions to the Whitham-Broer-Kaup(WBK) equation with the aid of symbolic com putation system Maple.
Analytical solutions of the three-dimensional Schr?dinger equation with an exponentially changing effective mass
Authors: Cai Chang-Ying  , Ren Zhong-Zhou  , Ju Guo-Xing  ,   (1)南京大学物理系，南京  210008; (2)南京大学物理系，南京  210008;井冈山学院物理系，吉安  343009; (3)南京大学物理系，南京  210008;兰州重离子加速器国家实验室原子核理论中心，兰州  730000
Published: December 2020

For an effective mass distribution that is an exponential function of the radial coordinate, the analytical solutions of the three-dimensional Schrdinger equ ation are obtained by using the coordinate transformation method for the referen ce problems with Coulomb potential, Kratzer potential and spherically square pot ential well of infinite depth, respectively. The explicit analytical expressions for the energy eigenvalues and the corresponding eigenfunctions of the three sy stems are presented.
Nonlinear feedback synchronization control of Liu chaotic system
Authors: Chen Zhi-Sheng  , Sun Ke-Hui  , Zhang Tai-Shan  ,   中南大学信息科学与工程学院，长沙  410083
Published: December 2020

Synchronization of a new chaotic system called Liu chaotic system is studied.Based on Lyapunov stabilization theorem and nonlinear feedback control method,the sufficient conditions and range of the controller's parameter for self_synchronization of Liu chaotic systems are derived.By combining the parameter adaptive control method and the nonlinear feedback control method,the synchronization of Liu system at speed with unified chaotic systems is implemented.Simulation results validate the proposed synchronization methode.
Characteristics of the premartensitic transition in the Ni50.5Mn24.5G25 single crystals
Authors: Cui Yu-Ting  , Chen Jing-Lan  , Liu Guo-Dong  , Wu Guang-Heng  , Liao Ke-Jun  , Wang Wan-Lu  ,   (1)商丘师范学院物理系,河南  476000;中国科学院物理研究所磁学国家重点实验室,北京  100080;重庆大学理学院应用物理系,重庆  400044; (2)中国科学院物理研究所磁学国家重点实验室,北京  100080; (3)重庆大学理学院应用物理系,重庆  400044
Published: December 2020

The characteristics of premartensitic transition on nearly stoichiometric Ni 505Mn245Ga25 single crystals have been investigated systematic ally by various methods, such as the ac magnetic susceptibility, resistance, mag netostriction, premartensitic transition strain and magnetization measurement. T he premartensitic transition strain in free samples was reported, and the enhanc ed premartensitic transition strain with an external magnetic field applied alon g the different directions was investigated. A large magnetostriction up to 505ppm in the [001] direction of the parent phase is obtained in a pulse magnetic field of about 80kA/m applied along the [010] direction at the premartensitic t ransition point, which is over five times larger than that in the parent phase. Based on the soft mode condensation and characteristic of the crystal growth, th e mechanism of the premartensitic transition strain was analyzed. The effect of magnetic field intervened premartensitic transition strain is attributed to the competition between the crystal lattice deformation induced by the enhancing mag netoelastic coupling and the intrinsic deformation originated from the soft-mode condensation. We found that the premartensitic transition further generated the anisotropy between two crystallographic directions of [001] and [010], which is proved by the magnetization measurement. Furthermore, the resulting strain prop erties, such as the largest magnetostriction, the saturated premartensitic trans ition strain and saturated field, have been discussed in detail.
Attosecond pulses emitted by a single energetic electron traversing an intense laser beam
Authors: Zheng Jun  , Sheng Zheng-Ming  , Zhang Jie  ,   中国科学院物理研究所光物理开放实验室，北京  100080
Published: December 2020

The attosecond x_ray pulse trains emitted by a single electron intersecting with an intense Gaussian laser beam have been investigated theoretically and numeric ally by use of Thomson scattering of free electrons. The temporal and spatial ch aracteristics of the radiation are presented for different laser amplitude param eters a0 (1—10) and initial energies of the electron γ0(1 —100MeV). It is found that the durations of the pulse trains and individual pul se depend significantly upon the laser beam width and intensity, as well as the electron energy. Specifically, the individual pulse duration, the separation bet ween neighboring pulses, and the duration of the pulse profile are all proportio nal to 1/γ20. The emission power and energy are propo rtional to　γ 60 and γ40, respectively. Whe n changing the laser amplitude a 0，the radiation power is proportional to a20, the individu al pulse duration to 1/a0, and the separation between pulses to a0. When keeping the laser amplitude while changing the beam w idth w0，the number of pulses in the profile, the duration of t he pulse profile, an d the emission energy are proportional to w0. If the laser powe r is fi xed while changing the beam width and intensity, the emission energy and profile duration of the emission pulse train are almost fixed. For a given laser amplit ude a0=1, a beam width w0 equal to 2 laser w avelengths, an d the initial electron energy of 10MeV，for example, the radiation profile of th e pulse trains has a duration of 14×10-3τ0, whic h is only a few attoseconds if the laser oscillation period　τ0 is a few f emotoseconds.
A new method for directly measuring frequency and intensity temporal profiles of attosecond XUV pulse simultaneously and completely
Authors: Ge Yu-Cheng  ,   清华大学工程物理系粒子技术与辐射成像国家专业实验室，北京  100084
Published: December 2020

A new method of phase determination is presented to measure the frequency and intensity temporal profiles of attosecond XUV pulses directly, simultaneously and completely. Using a cross correlation between femtosecond laser and attosecond X UV, such profiles can be reconstructed from photoelectron energy spectra measure d with two different laser intensities at 0° and 180° with respect to the line ar laser polarization. The method has a temporal measurement range from a quarte r to about half of laser oscillation period. The temporal resolution depends on the jitter and control precision of the laser and XUV pulses. The method can be used for ultra_fast measurement on attosecond time scale.