3,512 research outputs found

    Accretion process of the moon

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    Recent geochemical and geophysical data suggest that the initial temperature of the moon was strongly peaked toward the lunar surface. To explain such an initial temperature distribution, a simple model of accretion process of the moon is presented. The model assumes that the moon was formed from the accumulation of the solid particles or gases in the isolated, closed cloud. Two equations are derived to calculate the accretion rate and surface temperature of the accreting moon. Numerical calculations are made for a wide range of the parameters particle concentration and particle velocity in the cloud. A limited set of the parameters gives the initial temperature profiles as required by geochemical and geophysical data. These models of the proto-moon cloud indicate that the lunar outermost shell, about 400 km thick, was partially or completely molten just after the accretion of the moon and that the moon should have been formed in a period shorter than 1000 years. If the moon formed at a position nearer to the earth than its present one, the moon might have been formed in a period of less than one year

    Elastic wave velocities of Apollo 12 rocks at high pressures

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    New results of P- and S-wave velocity measurements on two Apollo 12 rocks, 12052 and 12065, under pressures up to 10 kbars are presented. These rocks are basalt-like crystalline rocks with a bulk density of about 3.26 g/cm^3 and a mean atomic weight of 24.5. Like the Apollo 11 rocks, the velocities and the wave transmission efficiency are surprisingly low at low pressures despite their relatively tight texture; at pressures below 200 bars, Q is estimated to be less than 100. The velocities increase very rapidly with pressure and approach 7.0 km/sec (P wave) and 3.9 km/sec (S wave) towards 10 kbars. No evidence is found for an increase of Q at 1 MHz with a reduction of the ambient pressure to 3 x 10^(-3) torr

    Oral ingestion of cow's milk immunoglobulin G stimulates some cellular immune systems and suppresses humoral immune responses in mouse

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    ArticleINTERNATIONAL IMMUNOPHARMACOLOGY. 6(8): 1315-1322 (2006)journal articl

    Metal-nonmetal transition in LixCoO2 thin film and thermopower enhancement at high Li concentration

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    We investigate the transport properties of LixCoO2 thin films whose resistivities are nearly an order of magnitude lower than those of the bulk polycrystals. A metal-nonmetal transition occurs at ~0.8 in a biphasic domain, and the Seebeck coefficient (S) is drastically increased at ~140 K (= T*) with increasing the Li concentration to show a peak of magnitude ~120 \muV/K in the S-T curve of x = 0.87. We show that T* corresponds to a crossover temperature in the conduction, most likely reflecting the correlation-induced temperature dependence in the low-energy excitations

    Two dimensionality in quasi one-dimensional cobalt oxides

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    By means of muon spin rotation and relaxation (μ+\mu^+SR) techniques, we have investigated the magnetism of quasi one-dimensional (1D) cobalt oxides AEn+2AE_{n+2}Con+1_{n+1}O3n+3_{3n+3} (AEAE=Ca, Sr and Ba, nn=1, 2, 3, 5 and ∞\infty), in which the 1D CoO3_3 chain is surrounded by six equally spaced chains forming a triangular lattice in the abab-plane, using polycrystalline samples, from room temperature down to 1.8 K. For the compounds with nn=1 - 5, transverse field μ+\mu^+SR experiments showed the existence of a magnetic transition below ∼\sim100 K. The onset temperature of the transition (TconT_{\rm c}^{\rm on}) was found to decrease with nn; from 100 K for nn=1 to 60 K for nn=5. A damped muon spin oscillation was observed only in the sample with nn=1 (Ca3_3Co2_2O6_6), whereas only a fast relaxation obtained even at 1.8 K in the other three samples. In combination with the results of susceptibility measurements, this indicates that a two-dimensional short-range antiferromagnetic (AF) order appears below TconT_{\rm c}^{\rm on} for all compounds with nn=1 - 5; but quasi-static long-range AF order formed only in Ca3_3Co2_2O6_6, below 25 K. For BaCoO3_3 (nn=∞\infty), as TT decreased from 300 K, 1D ferromagnetic (F) order appeared below 53 K, and a sharp 2D AF transition occurred at 15 K.Comment: 12 pages, 14 figures, and 2 table

    Does it make sense to talk about NΔ phase shifts?

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    The question of whether one can consistently define and extract nucleon-delta scattering parameters, phase shifts, and inelasticities from the partial-wave NN→NΔ amplitudes is discussed. We have studied the unitarity relation and identified the conditions under which the extraction of such quantities is meaningful. Then these conditions were tested in several coupled-channel models of the NN-NΔ system

    Magnetostrictive behaviour of thin superconducting disks

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    Flux-pinning-induced stress and strain distributions in a thin disk superconductor in a perpendicular magnetic field is analyzed. We calculate the body forces, solve the magneto-elastic problem and derive formulas for all stress and strain components, including the magnetostriction ΔR/R\Delta R/R. The flux and current density profiles in the disk are assumed to follow the Bean model. During a cycle of the applied field the maximum tensile stress is found to occur approximately midway between the maximum field and the remanent state. An effective relationship between this overall maximum stress and the peak field is found.Comment: 8 pages, 6 figures, submitted to Supercond. Sci. Technol., Proceed. of MEM03 in Kyot

    High energy gamma-rays and hadrons at Mount Fuji

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    The energy spectra of high energy gamma-rays and hadrons were obtained by the emulsion chamber with 40 c.u. thickness at Mt. Fuji (3750 m). These results are compared with the Monte Carlo calculation based on the same model which is used in a family analysis. Our data are compatible with the model of heavy-enriched primary and scaling in the fragmentation region
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