bluuebunny/crossref_metadata_2025 huggingface dataset:
LOCALIZED RESISTIVE STATE IN SUPERCONDUCTING METALLIC GLASS Zr78Co22
Authors: ZHOU XIAN-YI  , ZHANG QI-RUI  , GUAN WEI-YAN  ,   中国科学技术大学物理系
Published: November 2020

In this paper, we have studied systematically the l-V characteristic of the superconducting metallic glass Zr78Co22 without applied magnetic fields. It is observed that the transition from superconducting states to normal states is completed in steps as the current increasing. The properties of steps are localized and depend on current scanning rate. It is shown that the occurence of resistive steps is because of the inhomogenity of materials which leads to the ap-pearence of hot-spots. The equation of one-dimensional thermal flow may be used to described the localized resistive state of superconducting metallic glass Zr78Co22, in case of considering the effecs of interaction between hot-spots, selfabsorbing-heat of the sample itself, and so on.
FERROMAGNETIC RESONANCE OF CYLINDRICAL DOMAIN LATTICE
Authors: BI SI-YUN  ,   山东大学物理系
Published: November 2020

The recent experimental work on the ferromagnetic resonance of cylindrcal domain lattice at action of arbitrary magnetic field is reported. The device used in the experiments is a microwave microstrip transmission line placed between the poles of a electromagnet. Based on the experimental results, the present theories on the bubble mode resonance is analysed and some significant results are achieved.
ENERGY LEVEL SHIFTS AND NEPHELAUXETIC EFFECT OF RARE EARTHS IN SOLID
Authors: BI XIAN-ZHANG  , ZHANG SI-YUAN  ,   (1)吉林省教育学院; (2)中国科学院长春应用化学研究所
Published: November 2020

In this paper, the shifts of 5DJ and 7FJ energy levels of Eu3+ ion caused by crystal field effect, are calculated in 25 hosts containing Eu3+ ions. The relation between the calculated shifts and experimental values are analysed. The correct order on nephelauxetic effect shifts in these hosts is given.
TUNABLE IR STIMULATED RADIATION GENERATED BY TWO-STEP HYB1RD EXCITING IN Na2-Na SYSTEM
Authors: TANG XIAO-LING  , WANG ZU-GENG  , QIN LI-JUAN  , ZHENG YI-SHAN  ,   (1)华东师范大学物理系; (2)陕西师范大学物理系
Published: November 2020

We report the generation of turnable IR stimulated emission covering 3.39-3.46 μm, by using a new exciting mechanism called "two-step hybird exciting" in sodium molecular-atomic system. We analyse and discuss carefully this IR emission. The computed relative intensity of the IR emission varies with the pumping deturning. The computational results matched well with experimental data.
EXCITED STATES IN COLLISION OF SINGLE AND DOUBLE CHARGED IONS WITH ATOMS AND COMPARISONS OF EMISSION CROSS SECTIONS
Authors: LIU JIA-RUI  , LEI ZI-MING  , YANG FENG  , PAN GUANG-YAN  , YU DE-HONG  , SUN XIANG  ,   中国科学院物理研究所
Published: November 2020

Recent experimental results on generating of excited states in collisions of single, double charged ions with He, Ne, Ar are presented. Laboratory energy range of the beams of Heq+, Arq+ (q=1,2) ions are (70-170)×q keV. The optical measurement was performed by Optical Multichannel Analysis System, the wavelength range covered was 200-800 nm. Different processes of excitation have been observed in single and double charged ions collisions with atoms. The dependence of emission cross sections on the charge number of incident ions and potential energy defect is discussed.
ON THE STABILITY OF DRIFT WAVES WITH STRONG COLLISION
Authors: KE FU-JIU  , CAI SHI-DONG  , CHEN LIU  , ZHANG CHENG-FU  , QI XIANG-LIN  ,   (1)北京大学物理系; (2)北京航空学院应用数理系; (3)美国普林斯顿大学等离子体物理实验室; (4)中国科学院物理研究所
Published: November 2020

An integral eigenequation is derived for the strongly collisional plasma by applying the gyrokinetic technique. An analytical proof of the absolute stability for the drift wave in a slab geometry with finite magnetic shear is presented. The macroscopic motion of electrons parallel to the ambient magnetic field is taken into consideration and Lee-Chen-Nevins method is adopted in the proof.
THE DEFECTS AND THE NONRADIATIVE RECOMBINATION OF PHOTOGENERATED CARRIERS IN a-Si:H AND a-SiNx:H
Authors: WANG ZHI-CHAO  , TENG MIN-KANG  , ZHANG SHU-YI  , GE WANG-DA  , QIU SHU-YE  ,   (1)南京大学物理系声学研究所; (2)南京无线电元件十七厂; (3)汕头大学物理系
Published: November 2020

The defects and the nonradiative recombination of photogenerated carriers in a-Si:H and a-SiNx:H films are studied by using infrared spectrometer, spectrophotometer, photoacoustic Spectrometer and positron annihilation life-time spectrometer from various respects.
THEORY OF HYDROGEN CHEMISORPTION ON METAL SURFACES
Authors: FENG WEI-GUO  , SUN XIN  , CHIA-WEI WOO  ,   (1)复旦大学物理系; (2)美国加利福尼亚州立大学旧金山分校
Published: November 2020

Based on the theory of correlated-basis-functions, and with the "big molecular" model, we have presented a new theory of hydrogen chemisorption on metal surfaces. Through the variational numerical calculation with respect to the parameter of position of adatom, we obtained chemisoption energies, electron densities, and equilibrium distances for the hydropen chemisorption on metals Al (rs = 2.07), Mg (rs = 2.66), Li (rs =3.28) and Na (rs =3.99) We also made a comparison with some other representative theories.
ANALYSING THE LEVEL STRUCTURE OF 1P10 SERIES OF IONIZED ALUMINUM(Al Ⅱ) BY MULTICHANNEL QUANTUM DEFECT THEORY
Authors: YANG LI  , ZHAO YI-JUN  , ZHANG ZHI-JIE  ,   长沙工学院应用物理系
Published: November 2020

We have analysed the level structrue of perturbed Rydberg series 1P10 of Al Ⅱ using the multichannel quantum defect theory (MQDT). The analysis shows that the main series 3snp1P10 is perturbed so strongly by the doubly excited state 3p4s1P10 such that the latter has entirely distributed into the main series and does not correspond to a single spectrum line any more. The experimental energy levels are well reproduced and the energy levels for n≤50 are calculated.
MECHANICAL AND ELECTRICAL PROPERTIES OF DEFORMED AMORPHOUS ALLOYS
Authors: HE HUA-CHUN  ,   昆明贵金属研究所
Published: November 2020

The resistance changes,△R/R, of fifteen different kinds of Pd-, Cu-. Ni-, and Fe-based amorphous alloys in the presence of elastic and plastic deformations have been measured. The resistivity ρ, density d and proportional limit σp for several amorphous alloys as functions of shrinkage ψ have also been determined. The results on the curve of p-ε and △R/R-ε indicate the existence of elastic, anelastic, and the plastic regions. Stress p and △R/R increase linearly with strain e in the first two regions. Density, resistivity and proportional limit vary with ψ obviously, however, their changes are very small after ψ>30%. Mechanism of the plastic deformation occurring in amophous alloys is also discussed.
GROUP THEORETICAL DETERMINATION OF TWIN BOUNDARIES IN R-PHASE AND MARTENSITE OF Ni-Ti SHAPE MEMORY ALLOY
Authors: YI HU-CHUN  , ZHU MIN  , YANG DA-ZHI  ,   大连工学院材料工程系
Published: November 2020

Twin boundaries were determined in both R-phase and martensite of NiTi shape memory alloy using group decomposition theory. It was found that there are four variants existing in the R-phase with {110}p and {100}p twin planes between the variants. The four variants may form three types of self-accommodation groups. While in the martensite phase, there may be three variants with {110}p twin planes between the variants. The three variants have four possibilities to form a self-accommodation group. These results are in good agreement with the experiment.
BOUNDARY AND JUNCTION CONDITIONS FOR PLATEAU STRUCTURE OF DENSITY PROFILE IN A LASER PLASMA
Authors: ZHU SHI-TONG  , XU ZHI-ZHAN  , SHEN WEN-DA  ,   (1)上海科学技术大学物理系; (2)中国高等科学技术中心(世界实验室)理论物理中心; (3)中国科学院上海光学精密机械研究所
Published: November 2020

The shortcomings in previous treatments of boundary and junction conditions for the self-consistent density profile are analysed carefully. In order to reflect precisely the factual boundaries, the vacuum boundary and the plasma rest upstream are connected to the upper and lower density profile shelves by the self-similar solutions respectively, and the perfect matching at the sonic point is realized. Our analytic results agree well with computer simulation
AMANY-BODY UNIVERSAL APPROACH TO THERMALLY ACTIVATED MAGNETOELASTIC RELAXATION IN FERROMAGNETIC ALLOYS
Authors: WANG YANG-PU  , JIN QI-SMU  ,   苏州大学物理系
Published: November 2020

The rmally activated magnetoelastic relaxation in disordered ferromagnetic alloys is studied by using a new relaxation mechanism based on the concept of many-body interaction leading to an infrared divergence response. It nas been found that except the thermally assisted transitions of directional ordered atoms, the directional ordering, which causes a relaxation behavior of magnetic domain walls, includes two different classes of configurational tunnelling caused by many-body interactions. Based on this mechanism, a new relaxation law of magnetization and a new formula of magnetic disaccommodation were derived. Using Boltzmann superposition principle, an universal formula of internal friction was also derived, which was verified by experimental date.
GREEN'S FUNCTION THEORY OF PHASE TRANSITION IN ORDER-DISORDER TYPE FERROELECTRICS AND ANTIFERROELECTRICS
Authors: LI TING  , QIN ZI-KAI  ,   山东大学物理系
Published: November 2020

In this paper, we use the Green's function method with the symmetry decoupling scheme to study the phase transition in H-bond ferroelectric system. Some interesting results are obtained. Also, we find that the temperature and the order parameter at transition point, Tc and Sc, can be determined directly from the T-S relation, and the order of phase transition can be obtained naturally. The results are discussed in detail and compared with experiments.
A STUDY ON THE RELATIONSHIP BETWEEN THE SPONTANEOUS RADIATION AND THE STIMULATED RADIATION IN TRANSITION RADIATION FREE ELECTRON LASERS
Authors: LIU SHENG-GANG  , SUN YAN  ,   (1)成都电讯工程学院; (2)中国科学技术大学
Published: November 2020

As a fundamental theorem in free electron lasers, Madey Theorem reveals the relationship between the spontaneous radiation and the stimulated radiation. In this paper, this problem is studied for transition radiation free electron lasers. The results show that there is a formula corresponding to the first part of Madey Theorem, but the former is more complicated; while the second part remains the same. Then the results obtained are used to simplify the small signal gain calculation.
THE HYDROGENATION OF THE AMORPHOUS ALLOY Fe87V3Zr10
Authors: XU ZU-XIONG  , MA RU-ZHANG  , DUO LIANG  , DING WEI-QING  ,   (1)北京钢铁学院金属物理教研室; (2)北京师范大学
Published: November 2020

The hydrogenation of the amorphous alloy Fe87V3Zr10 is studied using secondary ion mass spectroscopy (SIMS) and Mossbauer spectroscopy (MS). It is shown that the atoms of hydrogen in charged samples combine preferentially with atoms of zirconium and produce clusters of ZrH, and a proportion of hydrogen combine with atoms of vanadium and iron and produce clusters of VH and FeH. the mechanism that hydrogen influences the magnetism of this alloy is discussed.
STUDY OF LASER IMPLOSION DYNAMICS BY FOUR-FRAME X-RAY SHADOWGRAPHY AND THEORETICAL SIMULATION
Authors: LIN ZUN-QI  , ZHANG YAN-ZHAN  , BI WU-JI  , LU HAI-HE  , HE XING-FA  , ZHAO ZHI-WEN  , WEI XIAO-CHUN  , SHI A-YING  , WANG XIAO-QIN  , LIN KANG-CHUN  , LI JIA-MING  , DONG QI  ,   (1)中国科学院上海光学精密机械研究所; (2)中国科学院物理研究所
Published: November 2020

We present here studies of laser imploded glass microballoons by the newly developed time-resolved four-frame X-ray shadowgraphy. The simulation results of our one-dimensional Lagrangian hydrodynamical computation code (WL code) are in good agreement with the diagnostic experiments. The joint effort of the diagnostic experiments and theoretical simulations is crucial to understand laser implosion dynamics.
MAGNETIC STRUCTURE OF Pr2(Fe0.8Co0.2)14B USING NEUTRON DIFFRACTIONS
Authors: JIN LONG-HUAN  , YAN QA-WEI  , LIU YING-LIE  ,   中国科学院物理研究所
Published: November 2020

In this paper, the crystallographic and magnetic structures of intermetallic compound Pr2(Fe0.8Co0.2)14B studied by neutron powder diffraction are reported. This compound crystallize in Nd2Fe14B type tetragonal structure, a = 8.8110?, c = 12.2307?. Assumming ferromagnetic spin configuration and easy magnetization along c axis and equal magnetic moment for Fe and Co atom on the same site, profile refinement of the measured neutron diffraction data gives the magnetic moments on two non-equivalent Pr sites Pr4f and Pr4g as 1.2 and 1.4 μB, and moments on six non-equivalent transition metal ion sites T16k1 T16k2, T8j1, T8j2, T4e, and T4c as 2.2, 2.1, 1.9, 3.1, 1.6 and 1.0 μB. Substituted Co atoms are distributed randomly among six non-equivalent sites, no preferred site occupation was observed.
A NEW MODE-LOCKED EQUATION FOR SYNCHRONOUSLY PUMPED DYE LASERS AND ITS SOLUTION
Authors: GUAN XIN-AN  , ZHAO ZHI-HONG  ,   南开大学现代光学研究所
Published: November 2020

A new mode-locked equation suitable for synchronously pumped dye lasers is presented, after the drawbacks in the conventional equation are pointed out. The analytical expressions for pulsewidth τ and pulse-intensity l0 are obtained by expanding the gain G(t) to second order of t only. The theoretical analyses are well consistent with experiments and can interpret some experimental phenomena which can not be explained by the second order solution of the original equation.
RATE EQUATION THEORY OF DEGENERATE FOUR WAVE MIXING
Authors: DING HONG-YU  , WU BAI-SHI  , YIN DA-JUN  , LI JIN-QUAN  ,   (1)西安交通大学物理系; (2)中国科学院安徽光学精密机械研究所
Published: November 2020

Degenerate four wave mixing is treated using the quantum theory of fradiation. Starting from the energy conservation and momentum conservation laws and using the transition rate-formula for quantum states, the equation of motion for photon number densities of four beams is derived and exact solutions are obtained. With these solutions, change of nonlinear reflectivity with the pump waves and the probe wave, and saturation, and parameter oscillation arc-described. Besides, comparisons are made between our theory and classical theory as well as Bloom's large signal experiment. It is shown that our theory is more accurate and reasonable.
A METHOD FOR CALCULATING DC CONDUCTIVITIES OF THE POROUS MEDIUM AND COMPOSITE (Ⅰ)——AN APPROACH TO THE POROUS MEDIUM WITH PERIODIC STRUTURE
Authors: GU GUO-QING  , TAO RUI-BAO  ,   复旦大学物理系
Published: November 2020

A first-principle approach to the calculation of dc conductivities of the porous medium and composite is developed. In this paper, the case of the porous medium with periodic structure is discussed in detail. The effective conductivities for many two dimensional porous systems are calculated by polynomial approximation, Fourier expansion using elimination procedure and iterative approach of Fourier expansion Critical exponents for the dc conductivity of Sierpinski carpets are also calculated by an improved iterative approach. All the theoretical results agree fairly with recent experimental measurements.
THE EXPERIMENT OF GENERATION AND MAINTAINANCE OF A FRC BY MEANS OF A ROTATING MAGNETIC FIELD
Authors: WU CHENG  , A. KNIGHT  , I. R. JONES  ,   (1)School of Physics Sciences,Finders University of Sounth Australia,Bedford Park,S. A. 5042; (2)中国科学院物理研究所
Published: November 2020

An experiment in which a rotating magnetic field was used to generate and maintain a FRC is described. The FRC life time appeared to be limited by the duration of the rotating field pulse (40 ms), there was no evidence of gross instabities.
INVESTIGATION OF THIN FILM Si3N4 FORMED BY LOW ENERGY ION IMPLANTATION
Authors: CHEN GUO-MING  , CHEN GUO-LIANG  , YANG JIE  , ZOU SHI-CHANG  ,   中国科学院上海冶金研究所
Published: November 2020

It was well known that the interaction of solid surface with low energy ion beam results in the phenomena of sputtering and implantation. The characteristics of thin film Si3N6 formed by implanting ions N2+ at energy 1350 eV into single crystal Si are studied in this paper.We consider that it is necessary to introduce the concept of effective dose for ion beam which depends on the thickness of damage layer and the etching rate of as-implanted silicon nitrides.
THE BETA-FUNCTION AND MASS GAP IN SU(2) LATTICE GAUGE THEORY FOR COUPLING LESS THAN ONE
Authors: YING HE-PING  , DONG SHAO-JING  ,   浙江大学物理系
Published: November 2020

Through changing lattice action, the Monte Carlo "observation window" is shifted into g24 lattice. The scaling behaviour and M= (3.9±1.0)σ1/2 are found in this region.
A METHOD FOR CALCULATING D. C. CONDUCTIVITIES OF THE POROUS MEDIUM AND COMPOSITE (Ⅱ)——AN APPROACH TO THE ISOTROPIC AND ANISOTROPIC COMPOSITE
Authors: GU GUO QING  , TAO RUI-BAO  ,   复旦大学物理系
Published: November 2020

The first-principle approach for calculating the D. C. conductivities of the composites is discussed systematically. The integral equation for determining the effective conductivities of the composites with local anisotropic componentes is derived, and a convenient method for calculating effective conductivity tensor is proposed. We have dealt with effective conductivity tensor of the composites with local anisotropic components. A theoretical method which can treat the more common composites with no periodicity is developed. A new approximate method for solving integral equation by means of expansion with two bases is also proposed, by which we can calculate composites with large porosity and complicate structure with high precision, and it could have the advantage of saving lot of computing time.
CONCENTRATED SUSPENSION THEORY OF SOUND ATTENUATION IN GRANULAR MEDIA AND THE APPLICATIONS
Authors: QIAN ZU-WEN  ,   中国科学院声学研究所
Published: November 2020

The concentrated suspension theory in granular media set up by the author is presented concisely in this paper. By comparing its numerical results with the relevant data published, a satisfactory consistency can be obtained. As far as the relationship of the attenuation coefficients in marine sediments to the frequency is concerned, there has been a controversy among some authors for a long time, i.e. it appears to be a linear dependence upon frequency in the high-frequency range (higher than several kilohertz) and to be some deviation from first power dependence in the low-frequency range (lower than 1 kilohertz). However, according to our theory, reasonable unity can be acheived for them. Through an investigation on the measurement of the granular media by means of the acoustic method, the author believe that besides the mean diameter, the second granular parameter (such as the sorting coefficient) is necessary for a full characterization of granular media.This theory may give a theoretical basis to design new equipment for measuring granular parameters.
CHARACTERISTICS OF ELECTRONIC WAVE FUNCTIONS IN SUPERLATTICES WITH RANDOM LAYER THICKNESS
Authors: PANG GEN-DI  , CAI JIAN-HUA  ,   (1)南京大学固体物理研究所; (2)上海交通大学凝聚态物理研究所
Published: November 2020

The wave functions of electrons in superlattices with random layer thicknesses are studied. They are localized in the direction perpendicular to the layers characteristic of one-dimensional systems and extended in the plane of the leyers. Numerical results of computation of localization lengths are given.
VARIATION OF HOLE CONCENTRATION INDUCED BY ELEMENT SUBSTITUTION AT Y AND Cu(I) SITES IN YBa2Cu3Oy SYSTEM
Authors: ZHAO YONG  , HE YE-YE  , ZHANG HAN  , ZHUGE XIANG-BIN  , XU ZHU-AN  , LI TAO-YU  , ZHANG QI-RUI  , TANG XIAO-MING  , ZHAO PENG-CHENG  ,   (1)北京大学物理系,北京,100871; (2)浙江大学分析测试中心,杭州,310027; (3)浙江大学化工系,杭州,310027; (4)浙江大学物理系,杭州,310027; (5)中国科学院低温技术实验中心,北京,100080
Published: November 2020

The origin and the regularity of the variation of hole concentration as well as the crystal structure and superconducting critical temperature versus the doping contents of Co for Cu (I) and Ca for Y in YBa2Cu3Oy are studied in this paper. The results reveal that the pattern in which the hole concentration in Cu-O sheets, Psh, is influenced greatly by the substitution depends upon the different substituting elements as well as the different atomic sites, e.g. the decrease of Psh in system substituted by Co for Cu (I) is from filling and localizing of holes, but the increase of Psh in system of Ca replacing for Y is due to the delocalization effect of the holes. When Y and Cu (1) are substituted simutaneously with Ca and Co respectively, the generation instead of the localization effect cf the holes is important for the change of Psh. In addition, the relationship between Psh and Tc is discussed.
THEORY OF THE BAND NONPARABOLICITY EFFECTS ON FR?HLICH POLARONS
Authors: LI FU-BIN  ,   淮北煤炭师范学院物理系,淮北,230035;中国矿业大学数力系.江苏省徐州市,221000;中国高等科学技术中心(世界实验室)
Published: November 2020

The influence of the nonparabolicity of band structure on Fr?hlich polarons is studied theoretically. The model used applies a simplified two-band approximation. Nonparabolicity is found to affect both the polaronic binding energy and the effective-mass renormalization. Comparing with the earlier theories, in addition to band nonparabolicity, we have considered the polaron effects. The theory presented in this paper agrees well with experimental results.
EFFECTIVE CONDUCTIVITY OF THE COMPOSITE MEDIUM WITH LAYERED INCLUSIONS
Authors: Gu Guo-qing  , Yu K. W.  ,   (1)上海机械学院系统工程系,上海,200093;中国高等科学技术中心(世界实验室); (2)香港理工学院应用物理系,香港九龙
Published: November 2020

Using Rayleigh model, we study dc conductivity of the composite medium with layered inclusions. A generalized identity suitable to this kind of composite medium is proved and a definition of effective conductivity of the systems is given. For the systems with cubic symmetry, an analytic formula for effective conductivity is derived.
MAGNETIC MOMENTS AND COERCIVE FORCE OF Tb1-xGdxFe2
Authors: ZHONG WEN-DING  , LIU ZUN-XIAO  ,   北京大学物理系,北京100871
Published: November 2020

The magnetization curves, the Curie temperature and the thermal dependence of the coercive force in the pseudobinary cubic Laves phase compounds Tb1-xGdxFe2(0≤x≤l) has been measured. The saturation magnetization decreases almost linearly from TbFe2 to GdFe2. The magnetic moment of the iron atoms is a constant(μFe -1.60±0.04μB) for the whole concentration range, while the moment of terbium atoms is smaller slightly than its free ion value of gJ = 9.0μB due to crystal-field effects. The coercive field has got two contributions: one cames from the intrinsic pinning of domain walls in the Peierls crystal pontential wells and the fluctuation of magnetocrystalline anisotropy at rare-earth site; this contribution is preponderant at low temperatures, decaying exponentially with increasing temperature. The other comes from the pinning of domain walls by the internal stresses, causing the appearance of free magnetic poles.
STATISTICAL CRITERION FACTOR OF THE STABILITY OF THE SIMULTANEOUS EQUATIONS FOR X-RAY QUANTI-TATIVE PHASE ANALYSIS WITHOUT STANDARDS
Authors: GUO CHANG-LIN  , HUANG YUE-HONG  ,   中国科学院上海硅酸盐研究所,上海200050
Published: November 2020

In this paper, a detailed analysis of the relationship between various criterion factors and result errors of a lot of simultaneous equations for X-ray quantitative phase analysis is carried out and the factor g for quantitative criticizing the stability of the equations is found. According to the g factor of the different equations composed by the different samples combination, one can select the normal equation to get the precise results. Practical quantitative analysis, have proved that the new method is quite explicit and applicable.
MOSSBAUER EFFECT STUDY OF Bi TYPE HIGH-TEMPERA TURE SUPERCONDUCTOR 119Sn
Authors: ZHANG DAO-YUAN  , YAN PEI-FANG  , BAI LIN-SEN  , WU YONG-HUA  , WANG XIAO-YANG  , RUAN YAO-ZHONG  ,   (1)中国科学技术大学材料科学与工程系; (2)中国科学技术大学基础物理中心; (3)中国科学技术大学物理系,合肥230026
Published: November 2020

In this work, 119Sn is used as probe-atom, nd room temperature Mossbauer measurement of Bi1.68Pb0.32Sr1.75Ca1.75Cu2.65-xSnxOy(x=0.2-0.8) sample is performed. Combined with the results of X-ray diffraction and electric characteristic measurement, the relation between the occupancy of Sn in the sample and its electric characteristics is analysed, and an conclusion that squarecoordinated Cu performs a chief influence on the electric characteristic of high-transition-temperature (Tc) phase superconductor is reached.
PROPAGATING CHARACTERISTICS OF ULTRASONIC WAVE IN THE MAGNETIC LIQID
Authors: DU YOU-WEI  , TONG XING-WU  , ZHONG WEI  , WANG TING-XIANG  , GAN CHANG-MING  , ZHANG XIAO-RONG  ,   (1)南京大学固体微结构物理国家实验室,南京,210008; (2)南京大学声学研究所,南京,210008
Published: November 2020

Here we report experimental results of propagating characteristics of ultrasonic wave and explain it in light of existing theories. First, we study the relaxation process after magnetic field built up. It is known that the particles form chain-like clusters when the magnetic field is applied. The process of the cluster for mation is a relaxation process. The ultrasonic velocity v as a function of magnetic field at field angle　θ= 0 and π/2 at 4MHz were measured. We have studied the dependence of velocity on. Concentrations of the magnetic particles and frequency. The experimental results can be explain by Tarapov's theory rather than th approach used by Parsons.
ANOMALOUS INFRARED VIBRATIONS OF NANOMETER- SIZED Fe2O3 PARTICLES
Authors: WU XIAO-CHUN  , ZOU BING-SUO  , YU BAO-LONG  , TANG GUO-QING  , ZHANG GUI-LAN  , CHEN WEN-JU  ,   南开大学现代光学研究所,天津300071
Published: November 2020

This paper reports the anomalous infrared spectra of nanometer-sized Fe2O3 particles under certain conditions: some IR absorption peaks obviously shift, theirrelative intensities are changed; all peaks are remarkably broadened; and a broadbackground-absorption band appears. It is suggested that these anomalous IR chac-teristics indicate thata structural phase transition occurs, which results from the polaronic effect due to the increasing of electron-phonon coupling. This effect not only contains the contribution of LO phonons, but also the contribution of softmodes produced by interfacial atoms or molecules.
A NEW PRESCRIPTION OF THE STOCHASTIC QUANTIZATION OF GAUGE THEORIES
Authors: CHEN REN  ,   上海师范大学物理系
Published: November 2020

By using the kernels consisting of the projectors and function δ(t), both the co-nvergence to equilibrium and to get the propagators in covariant gauge are solved to-gether under the vanishing initial condition. Thus, the SQ prescriptions of gauge and non-gauge fields are united in using only these same kernels. The Maxwell, Chern-Si-mon and the linear gravitational theories are considered respectively. Again, it is shown that the use of this kernel does not yield the influence on the equilibrium distri-bution.
Frontal eye field and caudate neurons make different contributions to reward-biased perceptual decisions
Authors: Fan Yunshu , Gold Joshua I , Ding Long
Published: November 2020

Many decisions require trade-offs between sensory evidence and internal preferences. Potential neural substrates include the frontal eye field (FEF) and caudate nucleus, but their distinct roles are not understood. Previously we showed that monkeys’ decisions on a direction-discrimination task with asymmetric rewards reflected a biased accumulate-to-bound decision process (Fan et al., 2018) that was affected by caudate microstimulation (Doi et al., 2020). Here we compared single-neuron activity in FEF and caudate to each other and to accumulate-to-bound model predictions derived from behavior. Task-dependent neural modulations were similar in both regions. However, choice-selective neurons in FEF, but not caudate, encoded behaviorally derived biases in the accumulation process. Baseline activity in both regions was sensitive to reward context, but this sensitivity was not reliably associated with behavioral biases. These results imply distinct contributions of FEF and caudate neurons to reward-biased decision-making and put experimental constraints on the neural implementation of accumulation-to-bound-like computations.
Circ_0008039 supports breast cancer cell proliferation, migration, invasion, and glycolysis by regulating the miR‐140‐3p/SKA2 axis
Authors: Dou Dongwei , Ren Xiaoyang , Han Mingli , Xu Xiaodong , Ge Xin , Gu Yuanting , Wang Xinxing , Zhao Song
Published: November 2020

Circular RNAs (circRNAs) have been shown to modulate gene expression and participate in the development of multiple malignancies. The purpose of this study was to investigate the role of circ_0008039 in breast cancer (BC). The expression of circ_0008039, miR‐140‐3p, and spindle and kinetochore‐associated protein 2 (SKA2) was detected by qRT‐PCR. Cell viability, colony formation, migration, and invasion were evaluated using methylthiazolyldiphenyl‐tetrazolium bromide (MTT) assay, colony formation assay, and transwell assay, respectively. Glucose consumption and lactate production were measured using commercial kits. Protein levels of hexokinase II (HK2) and SKA2 were determined by western blot. The interaction between miR‐140‐3p and circ_0008039 or SKA2 was verified by dual‐luciferase reporter assay. Finally, a mouse xenograft model was established to investigate the roles of circ_0008039 in BC in vivo. We found that circ_0008039 and SKA2 were upregulated in BC tissues and cells, while miR‐140‐3p was downregulated. Knockdown of circ_0008039 suppressed BC cell proliferation, migration, invasion, and glycolysis. Moreover, miR‐140‐3p could bind to circ_0008039 and its inhibition reversed the inhibitory effect of circ_0008039 interference on proliferation, migration, invasion, and glycolysis in BC cells. SKA2 was verified as a direct target of miR‐140‐3p and its overexpression partially inhibited the suppressive effect of miR‐140‐3p restoration in BC cells. Additionally, circ_0008039 positively regulated SKA2 expression by sponging miR‐140‐3p. Consistently, silencing circ_0008039 restrained tumor growth via increasing miR‐140‐3p and decreasing SKA2. In conclusion, circ_0008039 downregulation suppressed BC cell proliferation, migration, invasion, and glycolysis partially through regulating the miR‐140‐3p/SKA2 axis, providing an important theoretical basis for treatment of BC.
How relative deprivation increases aggressive behavior: Exploring the moderating roles of resource scarcity, deprivation intensity, and sanctions in a game task
Authors: Kassab Yara , Isemann Simon D. , Halbeisen Georg , Walther Eva
Published: November 2020

The present work investigated the influence of experimentally manipulated relative deprivation (RD) on aggressive behavior in a game context. Participants experienced personal RD as the difference between own rewards and the rewards of a fictitious other player. Going beyond previous research, three yet‐unexplored moderators of the RD–aggression link were experimentally tested: In Experiment 1 (N = 157), we tested the effect of the scarcity of resources one is deprived of, and the intensity of the RD experience in terms of the magnitude of the disadvantaged comparison. In Experiment 2 (N = 195), we investigated whether aggressive behavior is influenced by imposing possible or actual sanctions (i.e., costs) for aggression. The results show effects on aggressive behavior toward the other player that were mediated by the personal perception of RD and that only actual but not possible costs eliminated this indirect effect. Implications for the aggression‐related behavioral consequences of RD are discussed.
Observers use facial masculinity to make physical dominance assessments following 100‐ms exposure
Authors: Albert Graham , Wells Erika , Arnocky Steven , Liu Chang Hong , Hodges‐Simeon Carolyn R.
Published: November 2020

Research has consistently demonstrated that faces manipulated to appear more masculine are perceived as more dominant. These studies, however, have used forced‐choice paradigms, in which a pair of masculinized and feminized faces was presented side by side. These studies are susceptible to demand characteristics, because participants may be able to draw the conclusion that faces which appear more masculine should be rated as more dominant. To prevent this, we tested if dominance could be perceived when masculinized or feminized faces were presented individually for only 100 ms. We predicted higher dominance ratings to masculinized faces and better memory of them in a surprise recognition memory test. In the experiment, 96 men rated the physical dominance of 40 facial photographs (masculinized = 20, feminized = 20), which were randomly drawn from a larger set of faces. This was followed by a surprise recognition memory test. Half of the participants were assigned to a condition in which the contours of the facial photographs were set to an oval to control for sexual dimorphism in face shape. Overall, men assigned higher dominance ratings to masculinized faces, suggesting that they can appraise differences in facial sexual dimorphism following very brief exposure. This effect occurred regardless of whether the outline of the face was set to an oval, suggesting that masculinized internal facial features were sufficient to affect dominance ratings. However, participants' recognition memory did not differ for masculinized and feminized faces, which could be due to a floor effect.
Observation of Standing Spin Waves in a van der Waals Magnetic Material
Authors: Kapoor Lucky N. , Mandal Supriya , Adak Pratap Chandra , Patankar Meghan , Manni Soham , Thamizhavel Arumugam , Deshmukh Mandar M.
Published: November 2020

Spin waves are studied for data storage, communication, and logic circuits in the field of spintronics based on their potential to substitute electrons. The recent discovery of magnetism in 2D systems such as monolayer CrI3 and Cr2Ge2Te6 has led to a renewed interest in such applications of magnetism in the 2D limit. Here, direct evidence of standing spin waves is presented along with the uniform precessional resonance modes in the van der Waals magnetic material, CrCl3. This is the first direct observation of standing spin‐wave modes, set up along a thickness of 20 mm, in a van der Waals material. Standing spin waves are detected in the vicinity of both branches, optical and acoustic, of the antiferromagnetic resonance. Magnon–magnon coupling and softening of resonance modes with temperature enable extraction of interlayer exchange field as a function of temperature.
Electrochemical Delamination of Ultralarge Few‐Layer Black Phosphorus with a Hydrogen‐Free Intercalation Mechanism
Authors: Wang Ning , Mao Nannan , Wang Zhien , Yang Xue , Zhou Xi , Liu Haining , Qiao Shanlin , Lei Xingfeng , Wang Junru , Xu Hua , Ling Xi , Zhang Qiuyu , Feng Qingliang , Kong Jing
Published: November 2020

Due to strong interlayer interaction and ease of oxidation issues of black phosphorus (BP), the domain size of artificial synthesized few‐layer black phosphorus (FL‐BP) crystals is often below 10 µm, which extremely limits its further applications in large‐area thin‐film devices and integrated circuits. Herein, a hydrogen‐free electrochemical delamination strategy through weak Lewis acid intercalation enabled exfoliation is developed to produce ultralarge FL‐BP single‐crystalline domains with high quality. The interaction between the weak Lewis acid tetra‐n‐butylammonium acetate (CH3COOTBA) and P atoms promotes the average domain size of FL‐BP crystal up to 77.6 ± 15.0 µm and the largest domain size is found to be as large as 119 µm. The presence of H+ and H2O is found to sharply decrease the size of as‐exfoliated FL‐BP flakes. The electronic transport measurements show that the delaminated FL‐BP crystals exhibit a high hole mobility of 76 cm2 V–1 s–1 and an on/off ratio of 103 at 298 K. A broadband photoresponse from 532 to 1850 nm with ultrahigh responsivity is achieved. This work provides a scalable, simple, and low‐cost approach for large‐area BP films that meet industrial requirements for nanodevices applications.
The Importance of Schottky Barrier Height in Plasmonically Enhanced Hot‐Electron Devices
Authors: Zhao Shenyou , Yin Yanting , Peng Jun , Wu Yiliang , Andersson Gunther G. , Beck Fiona J.
Published: November 2020

Plasmonically enhanced hot‐electron (PEH) photodiodes are a new class of optoelectronic device with the potential to be selective to spectral position, polarization, and bandwidth. Reported solid‐state PEH devices based on metal nanoparticles generally have low performance, in part, due to low collection efficiency of photogenerated hot electrons. A correlation is found between the measured external quantum efficiency (EQE) and the temperature at which the ALD‐TiO2 is deposited by atomic layer deposition (ALD) in Au–TiO2‐based PEH photodiodes. By investigating the material properties of the TiO2, it is demonstrated that the change in EQE is driven by a change in the energy levels in the semiconductor. The results show that lowering the implied Schottky barrier height increases the collection efficiency of hot electrons over the junction, in agreement with existing analytical models. This work demonstrates the crucial role that barrier height plays in hot electron devices in general, and indicates that this is an important design consideration for the improvement of PEH photodetectors.
Layer‐Dependent Exciton Modulation Characteristics of 2D MoS2 Driven by Acoustic Waves
Authors: Sheng Lihang , Tai Guoan , Yin Yonghe , Hou Chuang , Wu Zitong
Published: November 2020

Acoustic waves were recently utilized to modulate and control the electronic, optical, and magnetic properties of 2D materials. Among 2D materials, the mechanically exfoliated MoS2 with a perfect crystal structure provides an ideal platform to study its exciton characteristics. However, layer‐dependent exciton modulation characteristics of the 2D materials are still not systematically investigated under acoustic waves. Here, the in situ confocal fluorescence spectroscopy is used to probe the behavior of the excitons in 2D MoS2 under acoustic excitation. The high‐frequency acoustic field with a radial vibration frequency of 200 kHz is used as the excitation source which is produced by the piezoelectric ceramic chip. The results show that the exciton characteristics strongly depend on the layer numbers of the MoS2: under acoustic excitation, the fluorescence quenching degree in the odd layers of the sheets with intrinsic piezoelectricity is remarkably larger than that in the even layers without piezoelectricity; moreover, the PL peak position of the MoS2 with the odd layers is blue‐shifted with increase of the applied power while that with the even layers remains unchanged. Thus, this work paves the way to develop high‐performance optical and optoelectronic devices driven by acoustic waves.
Optimizing Surface Chemistry of PbS Colloidal Quantum Dot for Highly Efficient and Stable Solar Cells via Chemical Binding
Authors: Hu Long , Lei Qi , Guan Xinwei , Patterson Robert , Yuan Jianyu , Lin Chun‐Ho , Kim Jiyun , Geng Xun , Younis Adnan , Wu Xianxin , Liu Xinfeng , Wan Tao , Chu Dewei , Wu Tom , Huang Shujuan
Published: November 2020

The surface chemistry of colloidal quantum dots (CQD) play a crucial role in fabricating highly efficient and stable solar cells. However, as‐synthesized PbS CQDs are significantly off‐stoichiometric and contain inhomogeneously distributed S and Pb atoms at the surface, which results in undercharged Pb atoms, dangling bonds of S atoms and uncapped sites, thus causing surface trap states. Moreover, conventional ligand exchange processes cannot efficiently eliminate these undesired atom configurations and defect sites. Here, potassium triiodide (KI3) additives are combined with conventional PbX2 matrix ligands to simultaneously eliminate the undercharged Pb species and dangling S sites via reacting with molecular I2 generated from the reversible reaction KI3 ⇌ I2 + KI. Meanwhile, high surface coverage shells on PbS CQDs are built via PbX2 and KI ligands. The implementation of KI3 additives remarkably suppresses the surface trap states and enhances the device stability due to the surface chemistry optimization. The resultant solar cells achieve the best power convention efficiency of 12.1% and retain 94% of its initial efficiency under 20 h continuous operation in air, while the control devices with KI additive deliver an efficiency of 11.0% and retains 87% of their initial efficiency under the same conditions.
Online food prices during the COVID‐19 pandemic
Authors: Hillen Judith
Published: November 2020

During the coronavirus disease‐2019 pandemic, online grocery shopping experienced a never seen popularity in many countries. To study how the globally active online grocer Amazon Fresh reacted to this extraordinary demand increase, we analyzed a large dataset of daily price quotes for over 19,000 products for the customer location, Los Angeles. We found that contrary to the US consumer food price index, the overall price level at Amazon Fresh did not increase during the pandemic, but even slightly decreased for several product groups. Amazon seems to follow its low‐price strategy also in the grocery sector, even in times of high demand. However, during the lockdown phase, there were more price increases for certain highly demanded product groups such as frozen and prepared foods. Moreover, fewer prices were communicated as promotional prices. Because this change did not influence the general price level, we conclude that such promotional prices are used more as a marketing tool than as a price‐setting instrument.
A descriptive analysis of the COVID‐19 impacts on U.S. pork, turkey, and egg markets
Authors: Hayes Dermot J. , Schulz Lee L. , Hart Chad E. , Jacobs Keri L.
Published: November 2020

The novel coronavirus SARS‐CoV2 (COVID‐19) severely disrupted the U.S. food supply chain. In its initial aftermath, and as we contemplate a potential reignition, the food supply chain industries, researchers, and policy makers search for evidence, causes, and consequences. This article uses publicly available data on the pork and egg industries and a survey of the turkey industry as a first step to document the impact of COVID‐19. Researchers can learn from the experiences in industries where disruptions evolve differently in the face of simultaneous supply‐ and demand‐side shocks and that stem from differences in structures of the supply chains. This early evidence is used to motivate future research needs and highlight opportunities for industry investments in resiliency strategies.
Risk perception and determinants in small‐ and medium‐sized agri‐food enterprises amidst the COVID‐19 pandemic: Evidence from Egypt
Authors: Abu Hatab Assem , Lagerkvist Carl‐Johan , Esmat Abourehab
Published: November 2020

The coronavirus disease‐2019 (COVID‐19) pandemic has disrupted many activities along agri‐food supply chains in developing countries and posed unprecedented challenges in particular to small and medium agri‐food enterprises (SMEs). Drawing on a survey of 166 Egyptian agri‐food SMEs, this study investigates differences in‐ and determinants of COVID‐19 business risk perception among these enterprises. The empirical results showed that risk perception was highly asymmetric across geographical regions. Enterprises with longer cash flow coverage periods and higher values of total assets perceived significantly lower risk levels, as cash and assets functioned as a buffer against the impact of COVID‐19. The findings of the study imply that the “just‐in‐time” approach and the absence of a proactive and preventative stance to risk management reduced the resilience of agri‐food SMEs to the risks presented by the pandemic. Generally, enterprises that operate both in domestic and export markets perceived lower COVID‐19 risks. Finally, the main export destination to which the surveyed enterprises export was a significant determinant of their risk perception. These findings could be useful to managers of agri‐food businesses in terms of better understanding of risks and promotion of risk management practices. More so, they can help design effective policy interventions to mitigate the impacts of the pandemic on Egyptian agri‐food SMEs and build up their resilience to future pandemics and shocks.
Secondary rail car markets for grain transportation and basis values
Authors: Wilson William , Lakkakula Prithviraj
Published: November 2020

Commodity marketing firms’ logistical strategies have escalated in importance in recent years and are a significant factor that affects interfirm competition. Railroads have formulated pricing and allocation mechanisms for rail‐cars, resulting in a relationship between basis values in commodity markets and logistical performance, including rail‐car velocity (trips per month). This study estimates the determinants of and relationship between the Pacific Northwest export basis for soybean and rail‐car values in the secondary market, as well as to evaluate the simultaneity between these variables. The results indicate that the export basis and rail‐car values in the secondary market are determined simultaneously, which has important implications for commodity trading firms and for analysts (both private and public) of the commodity marketing system.
Food consumption behavior during the COVID‐19 pandemic
Authors: Chenarides Lauren , Grebitus Carola , Lusk Jayson L. , Printezis Iryna
Published: November 2020

We conducted an online consumer survey in May 2020 in two major metropolitan areas in the United States to investigate food shopping behaviors and consumption during the pandemic lockdown caused by COVID‐19. The results of this study parallel many of the headlines in the popular press at the time. We found that about three‐quarters of respondents were simply buying the food they could get due to out of stock situations and about half the participants bought more food than usual. As a result of foodservice closures, consumers indicated purchasing more groceries than normal. Consumers attempted to avoid shopping in stores, relying heavily on grocery delivery and pick‐up services during the beginning of the pandemic when no clear rules were in place. Results show a 255% increase in the number of households that use grocery pickup as a shopping method and a 158% increase in households that utilize grocery delivery services. The spike in pickup and delivery program participation can be explained by consumers fearing COVID‐19 and feeling unsafe. Food consumption patterns for major food groups seemed to stay the same for the majority of participants, but a large share indicated that they had been snacking more since the beginning of the pandemic which was offset by a sharp decline in fast food consumption.
Genetic overlap and causality between substance use disorder and attention‐deficit and hyperactivity disorder
Authors: Vilar‐Ribó Laura , Sánchez‐Mora Cristina , Rovira Paula , Richarte Vanesa , Corrales Montserrat , Fadeuilhe Christian , Arribas Lorena , Casas Miquel , Ramos‐Quiroga Josep Antoni , Ribasés Marta , Soler Artigas María
Published: November 2020

Substance use disorder (SUD) often co‐occur at high prevalence with other psychiatric conditions. Among them, attention‐deficit and hyperactivity disorder (ADHD) is present in almost one out of every four subjects with SUD and is associated with higher severity, more frequent polysubstance dependence and increased risk for other mental health problems in SUD patients. Despite studies suggesting a genetic basis in the co‐occurrence of these two conditions, the genetic factors involved in the joint development of both disorders and the mechanisms mediating these causal relationships are still unknown. In this study, we tested whether the genetic liability to five SUD‐related phenotypes share a common background in the general population and clinically diagnosed ADHD individuals from an in‐house sample of 989 subjects and further explored the genetic overlap and the causal relationship between ADHD and SUD using pre‐existing GWAS datasets. Our results confirm a common genetic background between ADHD and SUD and support the current literature on the causal effect of the liability to ADHD on the risk for SUD. We added novel findings on the effect of the liability of lifetime cannabis use on ADHD and found evidence of shared genetic background underlying SUD in general population and in ADHD, at least for lifetime cannabis use, alcohol dependence and smoking initiation. These findings are in agreement with the high comorbidity observed between ADHD and SUD and highlight the need to control for substance use in ADHD and to screen for ADHD comorbidity in all SUD patients to provide optimal clinical interventions.