bluuebunny/crossref_metadata_2025 huggingface dataset:
INVESTIGATION OF AMPHOTERIC BEHAVIOR OF SILICON IMPLANTED INTO InP
Authors: SHEN HONG-LIE  , YANG GEN-QING  , ZHOU ZU-YAO  , ZOU SHI-CHANG  ,   中国科学院上海冶金研究所离子束开放研究实验室,上海,200050
Published: November 2020

The electrical properties and characteristics of photoluminescence (PL) at 11K for InP implanted with Si+ at 200℃ have been studied. It has been found that the sheet electron concentration in Si+ simply implanted sample tends to a saturation level with increasing the Si+ dose, while that in Si++P+ dually implanted sample increases greatly. The 11K PL spectra reveals that there exists Sip-Vp complex in Si+ implanted InP, which can be inhibited by co-implanting P+. The mechanism of improved electrical properties by Si++P+ dual implants is, also discussed.
ELECTRONIC STRUCTURE OF BORON-VACANCY COMPLEX IN SILICON
Authors: SHEN SAN-GUO  , FAN XI-QING  ,   郑州大学物理系,郑州,450052
Published: November 2020

A simplified "five vacant hybrid orbital" model is proposed for the boron-vacancy complex, and the defect wave function are calculated using an empirical tight binding Green function method under extended defect potential approximation. The calculated hyperfine interaction constants of the nearest neighbors of the vacancy and the probability distribution of defect wave function localized at atomic distants from the vacancy, are in good agreement with the electron-nuclear double-resonance experiment. The deep energy obtained is comparable with the value measured by deep-level transient-spectroscopy. The theoretical results provide a strong support to the conclusion that boron atom is located at the lattice position next to the vacancy and the defect is a B-V+ charge state.
A STUDY ON THE OPTICAL NONLINEARITY OF SOME NEW TYPES OF KERR MEDIA
Authors: LIU SI-MIN  , KANG MIN-JIAN  , ZHANG GUANG-YIN  , WU YUAN-QING  , XU JING-JUN  ,   南开大学物理系,天津,300071
Published: November 2020

We have restudied the optical nonlinearity of the solutions of Chinese tea in ethyl alcohol or water using z-scanning method. The study shows that the optical nonlinearity only depends on the laser-heating-induced negitive lens effect in the media.
INJECTED PARAMETRIC OSCILLATION IN LITHIUM VAPOR
Authors: ZHU BAO-QIANG  , XIA ZONG-JU  , ZOU YING-HUA  ,   (1)北京大学物理系,北京,100871; (2)北京大学物理系,北京,100871;北京大学物理系光学教研室
Published: November 2020

The injected 2s-3d two-photon resonant parametric oscillation in lithium vapor has been studied theoretically and experimentally. It's output, compared with general pamametric oscillation, has better monochromaticity and appears as a "sharper" conical radiation. Furthermore, the injected parametric oscillation is tunnable as we change the frequency of the seed beam on the red side of the 2s-2p transition of lithium atom.
TIME DEPENDENT CRITICAL CURRENT AT ZERO FIELD FOR SINTERED Tl2Ba2Ca2Cu3Oy SUPERCONDUCTOR
Authors: DING SHI-YING  , SHI KE-XIN  , ZENG CHAO-YANG  , YU ZHENG  , SHI ZHI-XIANG  , QIU LI  ,   南京大学物理系固体微结构实验室,南京,210008
Published: November 2020

A new method determining the distribution of flux pinning energy U0, is described. The method is mainly the measurement of time dependent zero field critical current for sintered high temperature superconductor magnetized in applied field. By means of this method, the U0 distribution of Tl2Ba2Ca2Cu3Oy at 78K is obtained. Based on the experimental result, the dispersion of reported U0 is discussed.
MAGNETIC AND M?SSBAUER SPECTRA STUDY OF YTi(Fe1-xCox)11
Authors: KONG LIN-SHU  , YANG YING-CHANG  ,   北京大学物理系,北京,100871
Published: November 2020

YTi(Fe1-xCox)11 crystallizes in the ThMn12-type tetragonal structure, with x ranging from 0.0 to 1.0, the Curie temperature increases with the increase of Co content. In order to understand the relation between magnetic properties and microst-ructure of these compounds, we studied their M?ssbauer spectra. The M?ssbauer effect measurements were carried out at room temperature on YTi(Fe1-xCox)11, with x equal to 0.0, 0.2 and 0.4. The best fits confirm that Co atoms preferentially occupy the j and f sites. The hyperfine fields of the measured samples reach a maximum at x = 0.2,which is in agreement with the results of magnetic measurements. By comparing the experimental results of M?ssbauer spectra of YTi(Fe1-xCox)11, Y2(Fe1-xCox)14B and YTi(Fe1-xNix)11, we analyze the difference of the 3d band structure between YTiFe11, and Y2Fe14B.
DEPENDENCE OF ISERS ON CONCENTRATION AND ADSORPTION ISOTHERM PROPERTY FOR SALICYLIC ACID IN SOLID-LIQUID SYSTEM
Authors: ZHENG HAI-CAI  , GOU ZENG-GUANG  , GUI MING  , LI XIU-YING  , MO YU-JUN  ,   (1)陕西师范大学物理系,西安710062; (2)中国科学院物理研究所,北京100080
Published: November 2020

The dependence of SERS intensity ISERS on the concentration c is studied experimentally for salicylic acid (SA) aqueous solution-Ag mirror system by measuring ISERS And the relation between ISERS and quantity of adsorbed molecules is also discussed. All the results suggest that the SERS technique indeed provides a efficient and high sensitive new method for studying adsorption isotherm property in solid-liquid system.
INVESTIGATION ON THE DEFECTS IN THE POST-DEFORM- ATION HYDROGEN-CHARGED POLYCRYSTALLINE PURE Co BY POSITRON ANNIHILATION
Authors: PENG DONG-LIANG  , WANG TIAN-MIN  , TONG ZHI-SHEN  ,   (1)兰州大学材料科学系,兰州730000; (2)兰州大学物理系,兰州730000; (3)中国纺织大学基础部,上海200051
Published: November 2020

Using positron lifetime and Doppler broadening lineshape parameter measurements, the recovery behaviors of defects in the deformed and post-deformation hydrogen-charged poly-crystalline pure Co have been studied. Experimental results indicate that the cathodic hydrogen-charging of deformed sample further introduce an additional amount of dislocations and vacancies as well as some vacancy clusters into it. However, it appears that mirrovoids and microcracks are not produced. The recovery temperature range of vacancies is 73-260℃; the annealing of dislocations and vacancy clusters occur in the range of 350-670℃. The migration activation energy of vacancy was measured to be 1.09±0.07eV.
A STUDY ON THE PROPERTIES OF VAPORIFIC SOURCE FOR ULTRAFINE PARTICLES
Authors: DENG ZHAO-JING  ,   西南师范大学物理系,重庆630715
Published: November 2020

Schaber and Martin have investigated exp rimentally the properties of the yield of (Na14Cl13)+ clusters in detail. They obtained the yield of (Na14Cl13)+ clusters as a function of oven-nozzle distance with the quadrupole mass spectrometer. In the present paper, by using the fractal theory, the distribution function is numericalls simulated and analyzed theoretically.
SURFACE RECONSTRUCTION OF GaSb(lOO)
Authors: HE ZHONG-QING  , HOU XIAO-YUAN  , DING XUN-MIN  ,   复旦大学应用表面物理国家重点实验室,上海200433
Published: November 2020

Various reconstructions (c(2×6), (1×3) and (2×3)) of the GaSb (100) surface have been studied by LEED, XPS and UPS. All the three reconstructed surfaces are terminated by Sb atoms with some rows missing. Annealing in an Sb environment of both MBE-prepared, Sbdimerized c(2×6) reconstruction and IBA-prepared, Gaislands-existing (2×3) reconstruction leads to the same (1×3) reconstruction.
CALCULATION OF ELECTRONIC POTENTIAL DISTRIBUTIONS AND PHOTOCONDUCTIVITY IN a-Si:H/a-SiNx:H SUPERLATTICES
Authors: WANG HONG  , ZHU MEI-FANG  , ZHENG DE-JUAN  ,   (1)中国科学技术大学研究生院物理学部,北京100039; (2)中国科学技术大学研究生院物理学部,北京100039;广东省汕头大学物理系,汕头515063
Published: November 2020

A reasonable model is proposed to calculatee the temperature dependence of photoconductivity (PC) in a-Si:H and a-Si:H/a-SiNx:H super lattices. Simmons-Taylor theory and the occupation statistics of correlated defects are used to describe band tail states and dangling bonds states. As in a-Si:H/a-SiNx:H superlattices, the electronic potential and charge distributions resulting from space-charge doping are calculated at various amounts of transferred charge and different asymmetry boundary conditions. The DC and PC are calculated with corresponding space potential and charge distributions. It is found that the enhancements of DC and PC in superlattices are mainly determined by the amouns of injected charge, and the influence of interface asymmetry is slight.
INTEGRABLE QUANTUM CHAIN AND THE REPRESENTATION OF QUANTUM GROUP SUq(2)
Authors: HOU BO-YU  , SHI KANG-JIE  , YANG ZHONG-XIA  , YUE RUI-HONG  ,   西北大学现代物理研究所,西安,710069
Published: November 2020

We discuss the XXZ spin chain with certain boundary term and the representation of quantum group SUq(2). It is shown that Bethe Ansatz states are highest weight states of SUq(2), with q arbitrary We construct the irreducible representation of the quantum group. For q a rational root of unity, we show that there are new solutions to the BA equations, We derived the state vectors | b′> by taking certain limit, from which we construct the type I and type Ⅱ representations of SUq(2).
PRIMARY STUDY ON THE IRRADIATION EFFECT OF HYDROGEN IONS ON DIAMOND-LIKE CARBON FILMS
Authors: WANG TIAN-MIN  , WANG WEI-JIE  , HAN PEI-GANG  , HUANG LIANG-FU  , LUO CHONG-TAI  ,   (1)兰州大学材料科学系,兰州,730010; (2)中国空间技术研究院兰州物理研究所,兰州,730000
Published: November 2020

Diamond-like carbon (DLC) films, prepared by dual-ion beam sputtering method on glass substrate, were irradiated by high energy hydrogen ions(H+) under different combinations of ion energy and irradiation dose. Raman spectroscopy, infra-red transmittance spectroscopy, electrical resistivity measurement and adhesive force determination were used to characterize the as-deposited and the irradiated films. The results showed that, comparing with that of as-deposited ones, the properties and structures of irradiated films were changed obviously: the infra-red transmittance in the range of 1450 to 6000 cm-1 was increased; the electrical resistivity had nearly no large change. The relative ratios of sp2 C-H bond to sp3 C-H bond and sp3 C-C bond to sp2 C-C bond were also increased, while the component of sp3 C-C bond and sp2 C-C bond was decreased because of H+ irradiation. On the basis of the above results., the relations between properties and structures for irradiation On the basis of the above results, the relations between properties and structures for irradiated films were discussed in detail between properties and structures for irradiated films were discussed in detail. It is concluded It is concluded that the H+ irradiation effect on DLC films is different from that of Cc or other heavier ions. The main role of H+ on the films is the teching effect on weaker bonds. We believe that it is possible to improve the properties of DLC films by means of high energy H+ irradiation.
INVESTIGATION ON FERROMAGNETIC PHASE IN THE 2-DIMENSION LARGE-U HUBBARD MODEL
Authors: LI DING-GUO  , ZHENG RUI-LIN  , HU LIAN  ,   (1)中国人民解放军海军工程学院物理研究室,武汉,430033; (2)中山大学微电子学研究所,广州,510275
Published: November 2020

From Zou and Anderson's spinon-bolon effective Hamiltonian, for very large Coulomb repulsion U, we consider the problem of ferromagnetism on the square lattice by studying the fluctuation effect of bosons (holons).
BEAM TEMPERATURE AND ENERGY BROADENING OF A HIGH-CURRENT HEAVY-ION BEAM IN AN AXIALLY SYMMETRIC ELECTRIC-FIELD
Authors: TIAN REN-HE  , ZHANG HUI-XING  ,   北京师范大学低能核物理研究所,北京,100875
Published: November 2020

In this paper, the beam temperature and energy broadening of a charged-particle beam in an axially symmetric electric-field (including the average field causel by the space charge) are presented. The result shows that in the drift region, this kind of energy broadening is directly proportional to the beam current and inversely proportional to the macro flow velocitp of the beam, so that for a heavy-ion beam with higher current, it will become an important part in the total energy broadening. As a numerical estimation, the energy broadening of a 1H ion beam with energy 20keV and current 20mA in the drift region is 26.5eV, while under the same conditions, the 121Sb ion beam has an energy broadening of 291.5eV which increases linearly with the increasing of beam current. The result about the beam temperature shows that in the drift region, the effect of space charge of the beam raises the beam temperature.
EFFECT OF ANHAMONICITY OF LAYERED TRANSVERSE-OPTICAL PHONONS ON HIGH-Tc SUPERCONDUCTIVITY
Authors: WANG HAN-TING  , XIONG SHI-JIE  ,   (1)南京大学物理系,南京,210008; (2)中国高等科学技术中心(世界实验室)理论物理分中心,北京,100080
Published: November 2020

The effect of anhamonicity of layered transverse-optical phonons on the interayer pairing is investigated by a canonical transformation from a two-level-system model. The results show that the critical temperature Tc is zero only when the difference Ω of the two levels is smaller than a critical value Ωc, and Tc increases with the decrease of Ω. It is consistent with the importance of the axial motion of the ions in the insulating sheets as has been revealed by the recent experiments.
HYDROGEN RECYCLING IN HL-1 TOKAMAK
Authors: PENG LI-LIN  , XU GUANG-BI  , YUAN CHENG-JIE  , CAO ZENG  , HUANG KE-QIANG  , ZHANG SHU-XUN  , YAN DONG-HAI  ,   核工业西南物理研究院,成都,610041
Published: November 2020

The recycling behaviours and their effects on the particle confinement under various operational conditions in HL-1 device are studied systematically. Using the particle balance equation and a hydrogen recycling model proposed by Howe, we estimated the global recycling coefficient R(t) from the data of Hα emission and others. The fueling ratio introduced by Ehrenberg is adopted to analyse the wall pumping and the wall fuelling as the wall/limiter condition or the kinds of inlet gas are altered. The phenomena of particle release after different plasma discharges are also observed and compared by using the quadrupole mass-spectrometer.
CALCULATION OF RELAXATION TIME DISTRIBUTION OF α-PEAK IN PVC WITH GAUSSIAN DISTRIBUTION
Authors: LI JIAN  , ZHANG LI-DE  , WANG JING  ,   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: November 2020

Dynamic mechanical loss spectra correspornding to different frequency were measured at ascending temperature for amorphous polymer PVC (a-PVC). It is found that measuring frequency dependance of the parameters of a-peak obviously exists. To determine the contribution of τ0 or ΔH distribution to τ distribution, on the basis of analysing relaxation time distribution (τ distribution) of α-peak in a-PVC, the parameters of τ0 and ΔH have been calculated in this paper.
DIRECTIONAL SOLIDIFICATION OF LAMELLAR EUTECTIC
Authors: LIU JUN-MING  ,   南京大学固体微结构国家重点实验室,南京210008
Published: November 2020

Directional solidification of lamellar eutectic has been studied both theoretically and experimentally. This process has been modeled through comparing it with directional solidification of an array of cells in binary alloys and developing of the Saffman-Taylor viscous fin-gerinig in a Hele-Shaw cell in an unitied framework. A coupling relation among the solute diffusion, the thermal transfer and the capillary effect of the growing interface has been derived. The well known scaling law λ2V = const can be derived from this relation. Directional solidification of regular Al-Al2Cu eutectic and irregular Al-Si eutectic has been investigated experimentally, the coupling relation has been verified. The solidifying interface profile and thermal transfer effect of solidification have also been discussed.
EVENT HORIZON AND TEMPERATURE OF SPHERICALLY CHARGED EVAPORATING BLACK HOLE
Authors: DAI XIAN-XIN  , ZHAO ZHENG  ,   北京师范大学物理系,北京100875
Published: November 2020

A new method is suggested to determine the event horizon and the Howking temperature of a spherically charged evaporating black hole. The Klein-Gordon equation near the event horizon is solved.
EFFECTS OF γ IRRADIATION ON LOSS CHARACTERISTICS OF SINGLE MODE OPTICAL FIBERS DOPED WITH RARE EARTH Er3+
Authors: HU KAI-SHENG  , LI ZONG-XIANG  , NING DING  , LI HAO  , ZHOU JIAN-PING  , LIU WEI-MIN  ,   (1)机械电子工业部电子材料研究所,天津300220; (2)天津技术物理研究所,天津300192
Published: November 2020

This papers presents the effects of Co-60 gamma irradiation on the absorption loss of single mode optical fibers doped with rare earth Er3+. The parameters of optical fibers are measured, prior to irradiation and after irradiation and UV bleaching. It has been found that absorption loss in the wavelength range of 0.80-1.60μm is greatly lager than those of unirra-diated fibers. Its increase law of absorption loss is similar to that of β ray irradiation. This similarity can be explained by Compton's effect. The induced loss can be partly bleached by UV, resulting in a better effect than heat annealing. In order to improve radiation resistivity, the elements with smaller atomic number should be selected as dopants in both core and cladding of the fiber.
TUNNEL BROADENING EFFECT ON INTERSUBBAND OPTICAL SATURATION IN SUPERLATTICES
Authors: PAN SHAO-HUA  , FENG SI-MIN  , CUI DA-FU  , YANG GUO-ZHEN  ,   (1)中国高等科学技术中心(世界实验室); (2)中国科学院物理研究所,北京,100080
Published: November 2020

By means of a new formalism of the Kronig-Penney model developed recently, the third order nonlinear optical effect of intersubband transitions in superlattices is studied. It is shown that there is a general relation between optical saturation intensity and tunnel bandwidth. The physical mechanism of this relation is analyzed.
THE EFFECT OF PHYSICAL PARAMETERS ON THE TEMPERATURE CHARACTERISTICS OF TWO-BEAM COUPLING IN PHOTOREFRACTIVE CRYSTAL
Authors: LIU JIN-SONG  ,   西安电子科技大学技术物理系,西安710071
Published: November 2020

The temperature characteristics of two-beam coupling in photorefractive crystal was discussed by using the one-carrier and one-level band-conduction model. The effect of physical parameters on the temperature characteristics was analyzed generally. In this paper, the concept of thermosenseless range has been put forward. If a crystal operates in this range, the optimum results of high efficiency, small thermonoise and small thermodrift of operation point can be obtained. The relationship between physical parameter and the location and extent of the range has been given, the method to amend experiment has been suggested.
ASSOCIATIVE IONIZATION OCCURRING IN COLLISIONS BETWEEN TWO Na(3P) ATOMS
Authors: SHEN YI-FAN  , LI WAN-XIN  ,   新疆大学物理系,乌鲁木齐830046
Published: November 2020

We have measured the cross section [σAl=4.2×10-17cm2±36％] for associative ioniza-tion occurring in collisions between two Na(3P) atoms, by measuring the current reselting from excitation of Na vapor with CW-laser radiation. The major experimental difficulty in measurements of this type is in the determination of the number density and spatial distribution of excited atoms. Here we have measured the excited-atom density by three independent methods, and we have studied the spatial distribution of excited atoms in detail. We have compared the cross section obtained by us at =523k with other experimental results.
A GAUGE INVARIANT VERSION OF SELF-DUAL THEORIES AND ITS QUANTIZATION
Authors: MIAO YAN-GANG  ,   兰州大学物理系,兰州730000
Published: November 2020

For a newly proposed Lagrangian of self-dual fields interacting with gauge fields, we cal-culate its one-cocycle condition, i.e. Wess-Zum ino term, and construct its gauge invariant ver-sion. Through canonical quantization we show that the gauge invariant theory in a proper gauge-fixing is equivalent to its gauge noninvarianr version. Moreover, by using the Baralin-Fradkin-Vilkovisky formalism, we point out that the equivalence is gauge independent.
EFFECT OF GRINDING ON Y-123 and Bi(Pb)-2223 PHASE SUPERCONDUCTORS
Authors: CHE GUAMG-CAN  , WU FEI  , DONG CHENG  , LI HUA  , YIN BO  , JIA SHUN-LIAN  , ZHOU YU-QING  , YANG YE  , XIONG JI-WU  , ZHAO ZHONG-XIAN  ,   中国科学院物理研究所国家超导实验室,北京100080
Published: November 2020

The effect of grinding on superconductors of Y-123 and Bi(Pb)-2223 phases and phase formation have been studied by means of X- ray diffraction, differential thermal analysis, scanning electron microscope and measurements of the superconductivity. The experimental results show that there is significant difference of grinding effect on Y-123 and Bi(Pb)-2223 phase superconductors. Grinding causes a change of crystalline state to amorphous one for Bi(Pb)-2223 phase superconductor. The effect of the mechanical strain from preparing process and accident on superconductivity of material should be taken into consideration.
DIFFERENTIAL CROSS SECTION CALCULATIONS OF THE e-H ELASTIC SCATTERING BASED ON A MULTIPLE-SCATTERING EXPANSION METHOD
Authors: LI TONG  , XU XIANG-DONG  , LIU QIANG  , QIAN QING  , CHEN XUE-JUN  ,   (1)清华大学现代应用物理系,北京100084; (2)中国高等科学技术中心(世界实验室)理论物理分中心
Published: November 2020

New calculations are conducted for the differential cross sections of e-H elastic scattering in the energy range of 100-200 eV based on a multiple-scattering expansion method. Discussion of the present results is given and comparison is made with experimental data.
STATISTICAL PHASE PROPERTIES OF LIGHT FIELDS
Authors: GUO HONG  , GUO GUANG-CAN  ,   (1)中国科学技术大学物理系,合肥230026; (2)中国科学院上海光学精密机械研究所,上海201800
Published: November 2020

Based on the definition of Pegg-Barnett phase state, the phase probability distribution functions of various light fields, such as Fock state, coherent state, squeezed state, pair coherent state, entangled state, and so forth and the time evolution of that of some single-mode light fields through the propagation in medium are analytically calculated, while the corresponding computational simulations are presented.
XUV SPECTRUM IN LASER-PRODUCED Ge PLASMA
Authors: HUANG WEN-ZHONG  , HE SHAO-TANG  , KONG LING-HUA  , HAN HONG-JUN  , FANG QUAN-YU  , CHEN GUO-XING  ,   (1)北京应用物理与计算数学研究所; (2)西南核物理与化学研究所
Published: November 2020

The XUV spectra emitted from line focused laser-produced Ge plasma were observed. A 1-m grazing-incidence spectrograph viewed the plasma in the axial direction. The spectra due to transitions in GeXX-GeXXVI were identified. The wavelengths and intensities were obtained. Calculations on spontaneous decay rates and oscillator strengths of the spectra were performed.
HETEROEPITAXY OF GaN BY USING AN IONIZED N SOURCE
Authors: HE ZHONG-QING  , DING XUN-MIN  , HOU XIAO-YUAN  , WANG XUN  , SHEN XIAO-LIANG  ,   (1)复旦大学分析测试中心; (2)复旦大学应用表面物理国家重点实验室和李政道物理学综合实验室
Published: November 2020

The ion beam producing ionization of N= has been successfully utilized as the N source for nitride growth. Cubic GaN thin films are thus grown on GaAs(100) substrates. The width of the (200) X-ray diffraction peak of the epilayer is 23′ only, and the high-resolution electron energy loss spectroscopy measurements show that the optical surface phonon of cubic GaN appears at the loss energy of 82 meV.
UNIDIRECTIONAL ANISOTROPY MAGNETORESISTANCE AND EXCHANGE COUPLING IN 81 NiFe/Cr MULTILAYER
Authors: CHEN HUI-YU  , LUO YOU-QUAN  , ZHU HONG  , WEN LIN-QING  ,   中国科学技术大学物理系
Published: November 2020

There are unidirectional anisotropy in 81 NiFe/Cr multilayers prepared by electronic beam evaporated, The samples exhibit asymmetrical hysteresis loop. which eguivalent to the existence of an exchange bias of the order of 1 Oe. Two branches of magnetoresistance loop measured with increasing and decreasing magnetic field respectively are different especially in transvers field condition. The maximum value of transvers magnetoresistance of some samples reaches 0.78% and with maximum anisotropy magnetoresistance （Ｒｍａｘ－Ｒｍｉｎ）／Ｒ of 4.72%.That value is more larger than the value 3%[１］ of 82 NiFe alloy with high quality. We consider that the ma-gnetoresistance effect of these multilayer not only caused by spin-orbit coupling ma-chanism but also under the influence of spin dependent scattering of conduction electron machanism.
KINETIC EQUATION AND TRANSPORTS OF PLASMA IN A CIRCULARLY-POLARIZED INTENSE LASER FIELD
Authors: SHENG ZHENG-MING  , XU ZHI-ZHAN  , MA JIN-XIU  , YU WEI  ,   中国科学院上海光学精密机械研究所
Published: November 2020

The kinetic equation for electron in an intense laser field is derived by transio-rming the Fokker-Planck equation into the local coordinate system of electron oscl-llation in the field. The electron-ion collision in circularly-polarized light is calcu-lated, and the electron-electron collision is discussed. The plasma thermo-electric transports are studied for different intensity regions of the circularly-polarized laser field. It is found that, when the electron quivervelocity in laser field is comparable with its thermal velocity, the thermo-electric transports can be largely decreased as compared to the case without laser field.
ENTROPY PROPERTIES OF THE FIELD IN THE TWO- PHOTON JAYNES-CUMMINGS MODEL WITH AN ADDITIONAL KERR MEDIUM
Authors: FANG MAO-FA  , ZHOU PENG  ,   (1)Institute de Eslructura de la Materia CSIC,Madrid 28006,Espana; (2)湖南师范大学物理系,长沙410081
Published: November 2020

In this paper, the entropy properties of the field in the two-photon Jaynes-Cu-mmings model with an additional Kerr medium are studied, the effect of nonlineari-ty interaction of the Kerr medium with the model field on the field entropy are discussed. With the help of quantum interference in phase space between two part of the bifurcation of the Q function of the field, the physical mechanism of properties of the field entropy are explained.
EXACT SOLUTION OF THE FOUR-WAVE MIXING IN PLASMA——THE TRANSMISSION GRATING CONFIGURATION
Authors: MENG YUE-DONG  , LI JIAN-GANG  , LUO JIA一RONG  ,   中国科学院等离子体物理研究所
Published: November 2020

In this paper, the universal set of degenerate and nearly degenerate four-wave mixing nonlinear coupling equations in plasma is presented in the transmission grating configuration and its exact solution appropriate for arbitrary nonlinear complex coupling parameters is given. This solution is not only suitable for photorafractive materials it can also be helpful for further theoretical study of FWM's phase conju-gation and development of new model nonlinear optical devices.
FORMATION AND MAGNETIC PROPERTIES OF Sm2Fe17-xMxC1.5(M=Ga,Si) COMPOUNDS
Authors: SHEN BAO-GEN  , KONG LIN-SHU  , WANG FANG-WEI  , CAO LEI  , ZHAN WEN-SHAN  ,   中国科学院物理研究所
Published: November 2020

Formation, structure and magnetic properties of Ｓｍ2Ｆｅ17-xＭxＣ1.5（Ｍ＝Ｇａ，Ｓｉ） compounds prepared by arc-melting were studied. The Ｓｍ2Ｆｅ17-xGaxＣ1.5(3≤x≤6) carbides crystallize in the rhombohedral Ｔｈ2Ｚｎ17-type structure and the single-phase compund of Ｓｍ2Ｆｅ17-xSixＣ1.5 can only be obtained as x is 2. It is found that the Curie temperature of Ｓｍ2Ｆｅ17-xGaxＣ1.5 compounds decreases monotonically with increasing Ga concentration x from 633K for x=2 to 351K for x=6，and the Tc of Ｓｍ2Ｆｅ15Si2Ｃ1.5 compound is 578K. All compounds studied in this work exhibit an easy c-axis anisotropy at room temperature. The anisotropy field of Ｓｍ2Ｆｅ14Ga3Ｃ1.5 and Ｓｍ2Ｆｅ15Si2Ｃ1.5 compounds is found td be 90 and 115 kOe, respectively. A room-temperature coercivity of 16 kOe is obtained in rapidly quenched Ｓｍ2Ｆｅ15Si2Ｃ1.5 alloy prepared at。speed of 25 m/s.
INVESTIGATION OF IMPURITIES IN THE STRESS APPLYING PARTS (SAPS) DOPED WITH B2O3 FOR POLARIZATION-MAINTAINING FIBERS
Authors: HU KAI-SHENG  , LIN YI-ZHEN  , LI GUANG-PING  , JIANG CHUN-XIANG  , LI YAN-SONG  , YAN PING  ,   电子工业部电子材料研究所
Published: November 2020

OH-radical concentration in the (SAPS) doped with B2O3 for PANDA fibers is measured by infrared absorption method. B, Si, 0 and N in SAPS are analysed X-ray photoelectron spectroscopy (XPS). The Ge distribution in the core and the cathod luminescence at core-cladding interface of SAPS are measured by scanning electron microscopy, The ratio of absorption coefficient between the fundamental stretching vibration and its first overtone of OH bond is explained theoretically by using a vibrator model.
Reinforcement regulates timing variability in thalamus
Authors: Wang Jing , Hosseini Eghbal , Meirhaeghe Nicolas , Akkad Adam , Jazayeri Mehrdad
Published: November 2020

Learning reduces variability but variability can facilitate learning. This paradoxical relationship has made it challenging to tease apart sources of variability that degrade performance from those that improve it. We tackled this question in a context-dependent timing task requiring humans and monkeys to flexibly produce different time intervals with different effectors. We identified two opposing factors contributing to timing variability: slow memory fluctuation that degrades performance and reward-dependent exploratory behavior that improves performance. Signatures of these opposing factors were evident across populations of neurons in the dorsomedial frontal cortex (DMFC), DMFC-projecting neurons in the ventrolateral thalamus, and putative target of DMFC in the caudate. However, only in the thalamus were the performance-optimizing regulation of variability aligned to the slow performance-degrading memory fluctuations. These findings reveal how variability caused by exploratory behavior might help to mitigate other undesirable sources of variability and highlight a potential role for thalamocortical projections in this process.
Increasing heart vascularisation after myocardial infarction using brain natriuretic peptide stimulation of endothelial and WT1+ epicardial cells
Authors: Li Na , Rignault-Clerc Stephanie , Bielmann Christelle , Bon-Mathier Anne-Charlotte , Déglise Tamara , Carboni Alexia , Ducrest Mégane , Rosenblatt-Velin Nathalie
Published: November 2020

Brain natriuretic peptide (BNP) treatment increases heart function and decreases heart dilation after myocardial infarction (MI). Here, we investigated whether part of the cardioprotective effect of BNP in infarcted hearts related to improved neovascularisation. Infarcted mice were treated with saline or BNP for 10 days. BNP treatment increased vascularisation and the number of endothelial cells in all areas of infarcted hearts. Endothelial cell lineage tracing showed that BNP directly stimulated the proliferation of resident endothelial cells via NPR-A binding and p38 MAP kinase activation. BNP also stimulated the proliferation of WT1+ epicardium-derived cells but only in the hypoxic area of infarcted hearts. Our results demonstrated that these immature cells have a natural capacity to differentiate into endothelial cells in infarcted hearts. BNP treatment increased their proliferation but not their differentiation capacity. We identified new roles for BNP that hold potential for new therapeutic strategies to improve recovery and clinical outcome after MI.
Data quantity is more important than its spatial bias for predictive species distribution modelling
Authors: Gaul Willson , Sadykova Dinara , White Hannah J. , Leon-Sanchez Lupe , Caplat Paul , Emmerson Mark C. , Yearsley Jon M.
Published: November 2020

Biological records are often the data of choice for training predictive species distribution models (SDMs), but spatial sampling bias is pervasive in biological records data at multiple spatial scales and is thought to impair the performance of SDMs. We simulated presences and absences of virtual species as well as the process of recording these species to evaluate the effect on species distribution model prediction performance of (1) spatial bias in training data, (2) sample size (the average number of observations per species), and (3) the choice of species distribution modelling method. Our approach is novel in quantifying and applying real-world spatial sampling biases to simulated data. Spatial bias in training data decreased species distribution model prediction performance, but sample size and the choice of modelling method were more important than spatial bias in determining the prediction performance of species distribution models.
Observability of ultraviolet Ni lines in the atmosphere of transiting Earth‐like planets
Authors: Young Mitchell E. , Fossati Luca , Johnstone Colin , Salz Michael , Lichtenegger Herbert , France Kevin , Lammer Helmut , Cubillos Patricio E.
Published: November 2020

Nitrogen is a biosignature gas that cannot be maintained in its Earth‐like ratio with CO2 under abiotic conditions. It has also been proven to be notoriously hard to detect at optical and infrared wavelengths. Fortunately, the ultraviolet region, which has only recently started being explored for terrestrial exoplanets, may provide new opportunities to characterize exoplanetary atmospheric nitrogen. In this work, the future prospects for detecting atomic nitrogen absorption lines in the transmission spectrum of an Earth‐like planet orbiting in the habitable zone of a Sun‐like star with LUVOIR are explored. Using the nonlocal thermodynamic equilibrium spectral synthesis code Cloudy, we produce a far‐ultraviolet atomic transmission spectrum for an Earth–Sun‐like system and identify several nitrogen features, including both Ni and Nii lines. We calculate the number of transits required for 1σ and 3σ detections of the planetary Ni λ1200 triplet signal with the G120M grating of the LUMOS spectrograph designed for LUVOIR as a function of distance to the system and stellar ultraviolet emission. The minimum number of transit observations necessary for 1σ and 3σ detections of atomic N are 188 and 1,685, respectively, for a system located at a distance of 1 pc with 100 times the solar ultraviolet flux. Given that the orbital period of an Earth–Sun system is 1 year, it is not feasible to detect atomic N in the transmission spectrum for these systems. Future studies in this direction should therefore focus on Earth‐like planets orbiting in the habitable zone of M dwarfs.
For the Benefit of All Men: Oceanography and Franco‐American Scientific Diplomacy in the Cold War, 1958–1970**
Authors: Martínez‐Rius Beatriz
Published: November 2020

In the 1960s, the growing strategic importance of ocean exploration led the French government to develop greater capacity in marine scientific research, aiming to promote cooperative and diplomatic relations with the leading states in ocean exploration. Devised during Charles de Gaulle's government (1958–1969), the restructuring of French oceanography culminated, in 1967, in the establishment of the state‐led Centre National pour l'Exploitation des Océans (CNEXO). Beyond being intended to control the orientation of marine research at a national level, the CNEXO's mission was to use scientific diplomacy to balance a desire for enhancing international cooperative relations in oceanography with French ambitions to equal the USA's leading capacity to explore the oceans. Its director, the naval officer Yves la Prairie, played a crucial role in articulating scientific, national, and diplomatic interests for France in the oceans.
Bicarbonate Recognition Features of a Naphthobipyrrole‐strapped Calix[4]pyrrole
Authors: Oh Ju Hyun , Yang Ju Ho , Choi Han‐Byeol , Kim Sung Kuk
Published: November 2020

A calix[4]pyrrole (1) strapped with a naphthobipyrrole was prepared and its ability to bind the bicarbonate anion (HCO3−) was investigated via 1H NMR and UV/Vis spectroscopic analyses. The resulting spectral data revealed that receptor 1 was capable of recognizing HCO3− with high affinity in solutions as well as in the solid state. In CD2Cl2, it was inferred from 1H NMR spectroscopic titration experiment that HCO3− interacts with receptor 1 via two different modes with the first involving HCO3− being hydrogen bonded to all six NH protons of the receptor. This interaction is followed by a deprotonation process of the bipyrrole NHs upon the subsequent addition of HCO3− while the anion remains hydrogen‐bonded to the calix[4]pyrrole NHs. In the presence of methanol, the bound bicarbonate anion was converted into an unstable monomethyl carbonate anion (CH3OCO2−) that was then stabilized by forming a complex with receptor 1.
PQQ‐dependent Dehydrogenase Enables One‐pot Bi‐enzymatic Enantio‐convergent Biocatalytic Amination of Racemic sec‐Allylic Alcohols
Authors: Gandomkar Somayyeh , Rocha Raquel , Sorgenfrei Frieda A. , Montero Lía Martínez , Fuchs Michael , Kroutil Wolfgang
Published: November 2020

The asymmetric amination of secondary racemic allylic alcohols bears several challenges like the reactivity of the bi‐functional substrate/product as well as of the α,β‐unsaturated ketone intermediate in an oxidation‐reductive amination sequence. Heading for a biocatalytic amination cascade with a minimal number of enzymes, an oxidation step was implemented relying on a single PQQ‐dependent dehydrogenase with low enantioselectivity. This enzyme allowed the oxidation of both enantiomers at the expense of iron(III) as oxidant. The stereoselective amination of the α,β‐unsaturated ketone intermediate was achieved with transaminases using 1‐phenylethylamine as formal reducing agent as well as nitrogen source. Choosing an appropriate transaminase, either the (R)‐ or (S)‐enantiomer was obtained in optically pure form (>98 % ee). The enantio‐convergent amination of the racemic allylic alcohols to one single allylic amine enantiomer was achieved in one pot in a sequential cascade.
Points to Consider for Implementation of the ICH E17 Guideline: Learning from Past Multiregional Clinical Trials in Japan
Authors: Asano Kunihito , Aoi Yoko , Kamada Shuji , Uyama Yoshiaki , Tohkin Masahiro
Published: November 2020

We identified the major points that are described in the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH) E17 guideline but have not been considered in the past multiregional clinical trials (MRCTs) used for drug approval in Japan to elucidate potential challenges in the implementation of the ICH E17 guideline in Japan. Based on the analysis of 167 MRCTs of 130 drugs, several points, such as the same dose setting and consistency between the overall and Japanese populations, in addition to good clinical practice compliance, have been well considered in ≥ 75% of MRCTs. In contrast, the use of relevant guidelines for disease and primary end point definitions, standardization of efficacy/safety information, sample size allocation, as well as training/validation on subject selection and primary end point, have been addressed less adequately and may need to be considered when planning future MRCTs. This study provides useful information for the implementation of the ICH E17 guideline in Japan.
Intersegment mismatch mitigation with multidimensional dynamic element matching digital to analog converters
Authors: Babaei Bardia , Hashemipour Omid
Published: November 2020

In this paper, a two‐dimensional dynamic element matching digital to analog converter (2D DEM DAC) is proposed having less design complexity compared to the conventional 2D DEM DAC. A novel unit element selection algorithm is presented in order to alleviate the need for consecutive elements selection that is mandatory in the conventional 2D DEM DAC. The flexibility of this algorithm leads to the introduction of a generalized multidimensional DEM DAC applicable to any resolutions. The multidimensional structure mitigates intersegment mismatch error and improves the spurious‐free dynamic range (SFDR) and intermodulation distortion (IMD). A 12‐bit 2D DEM DAC is simulated in 65‐nm CMOS process using the digital return‐to‐zero (DRZ) technique with 1.2 V of supply voltage and power dissipation of 26 mW. The simulation results show 63.4‐ and 60.71‐dB SFDR at near DC and Nyquist frequency, respectively, and <−61‐dB IMD with 1.25‐GHz sampling frequency.
Herd‐immunity across intangible borders: Public policy responses to COVID‐19 in Ireland and the UK
Authors: Colfer Barry
Published: November 2020

The responses to COVID‐19 in Ireland and the UK differed, and will have consequences for life in these islands that will extend far beyond the current crisis. Ireland went into lockdown relatively early on 12 March, while after a slow initial response, with plans for herd immunity, the UK started introducing restrictions around 20 March and quickly became a world leader in cases. While the UK has also presented similar responses seen elsewhere in Europe, one further area of note sees the devolved responses in different parts of the UK diverge considerably. These differences cannot be explained purely in terms of epidemiological conditions, as the trajectories of the virus in England, Scotland, Wales, and Northern Ireland are broadly similar. The reality is that the leaders of the devolved governments reached different political judgments from PM Johnson, which may bring further pressure to bear on the UK's constitutional makeup.
Intraday conditional value at risk: A periodic mixed‐frequency generalized autoregressive score approach
Authors: Eckernkemper Tobias , Gribisch Bastian
Published: November 2020

We propose a copula‐based periodic mixed frequency generalized autoregressive (GAS) framework in order to model and forecast the intraday exposure conditional value at risk (ECoVaR) for an intraday asset return and the corresponding market return. In particular, we analyze GAS models that account for long‐memory‐type of dependencies, periodicities, asymmetric nonlinear dependence structures, fat‐tailed conditional return distributions, and intraday jump processes for asset returns. We apply our framework in order to analyze the ECoVaR forecasting performance for a large data set of intraday asset returns of the S&P500 index.
Einteilung von Boden in Homogenbereiche bei maschinellen Tunnelvortrieben – Kennwerte, Vortriebsabschnitte, Beispiele
Authors: Budach Christoph
Published: November 2020

Die Einteilung des Baugrunds in Homogenbereiche spielt bereits seit 2015 eine wichtige Rolle bei der Kalkulation und Ausführung von Infrastrukturprojekten. Die Anzahl der Projekte, bei denen der Baugrund in Homogenbereiche unterteilt wird, wenn Tunnelbohrmaschinen im Lockergestein genutzt wurden, ist aktuell hingegen noch sehr gering, wird in den kommenden Jahren aber weiter steigen und somit die Einteilung des Baugrunds an Bedeutung gewinnen. Bei maschinellen Vortrieben im Lockergestein können u. U. mehrere Schichten an der Ortsbrust auftreten, die bei der Einteilung des Baugrunds in Homogenbereiche zu berücksichtigen sind. Der vorliegende Beitrag geht auf die wesentlichen Merkmale bei der Einteilung des Baugrunds in Homogenbereiche bei maschinellen Vortrieben im Lockergestein unter Berücksichtigung der DIN 18312:2019 und der aktuellen Empfehlung des Deutschen Ausschusses für unterirdisches Bauen e. V. (DAUB) zur Auswahl von Tunnelbohrmaschinen ein. Ferner werden Empfehlungen zusammengefasst, welche über die in DIN 18312:2019 aufgeführten geotechnischen Parameter hinaus bestimmt bzw. welche Versuche zusätzlich durchgeführt werden sollten, um den Baugrund für den Vortrieb zu beschreiben. Es werden Möglichkeiten aufgezeigt, wie bei unterschiedlichen Baugrundverhältnissen die Einteilung in Homogenbereiche erfolgen kann und wie eine Umsetzung im Leistungsverzeichnis möglich ist. Basierend auf diesen Möglichkeiten werden Empfehlungen aufgeführt, wie die Berücksichtigung von geo‐ und tunnelbautechnischen Besonderheiten eines maschinellen Vortriebs im Lockergestein zu einer transparenten Ausschreibung führt.
Thermochemistry and viscous heat dissipative effects on unsteady upper‐convected Maxwell fluid flow past a stretching vertical plate with thermophysical variables
Authors: Idowu Amos S. , Olabode John O.
Published: November 2020

In this paper, unsteady upper‐convected Maxwell fluid flow with variability in viscosity, thermal conductivity, and mass diffusivity is presented. The effects of chemical reaction, internal heat generation, and viscous dissipation with respect to variability properties were explored. The governing partial differential equations were transformed with the appropriate similarity transformation variables into nonlinear coupled ordinary differential equations. The spectral collocation method was used to solve the resulting ordinary differential equations. Hence, the effects of various parameters such as temperature‐dependent viscosity and thermal conductivity, mass diffusivity parameters among others on velocity, temperature, concentration, skin friction, local heat and mass transfers were presented in graphs and tables. It is seen that heat and molecules of the fluid disperse faster as a result of destructive chemical reaction, while, the temperature‐dependent viscosity and thermal conductivity gave increasing profiles of the momentum and thermal boundary layer. The viscous dissipative parameter generates heat and yields a buoyancy force in consequence.
Radiative CNT‐based hybrid magneto‐nanoliquid flow over an extending curved surface with slippage and convective heating
Authors: Ali Asgar , Jana R. N. , Das Sanatan
Published: November 2020

This study concentrates on the hydrothermal prominence of a mixed convective flow of a hybrid nanoliquid over a convectively heated extending curved surface under the influence of a uniform transverse magnetic field. Two types of carbon nanotubes (CNTs), namely single‐walled carbon nanotubes (SWCNTs) and multi‐walled carbon nanotubes (MWCNTs), and magnetite nanoparticles are dispersed in the host liquid (water) to simulate the hybrid nanoliquid flow model. First‐ and second‐order velocity slip conditions and nonlinear radiative heat flux are incorporated in this model. First, the system of governing partial differential equations is changed into nonlinear ordinary differential equations through the utilization of appropriate transformations and computed numerically via MATLAB built‐in function bvp4c based on the three‐stage Lobatto IIIA technique. The consequences of physical and geometrical parameters pertinent to this analysis on the dimensionless physical quantities of interest are deliberated using requisite graphs and tables. Our simulation communicates that the first‐order velocity slip parameter decreases the velocity profile, whereas the second‐order velocity slip parameter is found to be augmented. The suspension of CNTs in the magnetite nanoliquid improves the local surface drag force but diminishes the local heat flux. Moreover, it is examined that SWCNTs have greater impacts than MWCNTs.
Hemostasis in pregnant women with COVID‐19
Authors: Ciavarella Alessandro , Erra Roberta , Abbattista Maria , Iurlaro Enrico , Boscolo‐Anzoletti Massimo , Ossola Manuela Wally , Mosca Fabio , Ferrazzi Enrico , Peyvandi Flora , Martinelli Ida
Published: November 2020

Coagulation parameters investigated in this pilot study were similar in pregnant women with COVID‐19 who were asymptomatic or had mild symptoms, and in pregnant women without COVID‐19 infection.
Dosing Recommendations for Lamotrigine in Children: Evaluation Based on Previous and New Population Pharmacokinetic Models
Authors: Tauzin Manon , Tréluyer Jean‐Marc , Nabbout Rima , Billette de Villemeur Thierry , Desguerre Isabelle , Aboura Radia , Gana Ines , Zheng Yi , Benaboud Sihem , Bouazza Naim , Chenevier‐Gobeaux Camille , Freihuber Cécile , Hirt Déborah
Published: November 2020

Lamotrigine is a broad‐spectrum antiepileptic drug with high interindividual variability in serum concentrations in children. The aims of this study were to evaluate the predictive performance of pediatric population pharmacokinetic (PPK) models published on lamotrigine, to build a new model with our monitoring data and to evaluate the current recommended doses. A validation cohort included patients treated with lamotrigine who had a serum level assayed during therapeutic drug monitoring (TDM). PPK models published in the literature were first applied to the validation cohort. We assessed their predictive performance using mean prediction errors, root mean squared errors, and visual predictive checks. A new model was then built using the data. Dose simulations were performed to evaluate the doses recommended. We included 270 lamotrigine concentrations ranging from 0.5 to 17.9 mg/L from 175 patients. The median (range) age and weight were 11.8 years (0.8‐18 years) and 32.7 kg (8‐110 kg). We tested 6 PPK models; most had acceptable bias and precision but underestimated the variability of the cohort. We built a 1‐compartment model with first‐order absorption and elimination, allometric scaling, and effects of inhibitor and inducer comedications. In our cohort, 22.6% of trough concentrations were below 2.5 mg/L. In conclusion, we proposed a PPK model that can be used for TDM of lamotrigine in children. In our population, a high percentage of children had low trough concentrations of lamotrigine. As the intervals of recommended doses are large, we suggest aiming at the higher range of doses to reach the target concentration.