1,755 research outputs found

    Evaluation of scanning earth sensor mechanism on engineering test satellite 4

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    The results of the analysis and the evaluation of flight data obtained from the horizon sensor test project are described. The rotary mechanism of the scanning earth sensor composed of direct drive motor and bearings using solid lubricant is operated satisfactorily. The transmitted flight data from Engineering Test Satellite IV was evaluated in comparison with the design value

    Partial and macroscopic phase coherences in underdoped Bi2{}_{2}Sr2{}_{2}CaCu2{}_{2}O8+δ{}_{8+{\delta}} thin film

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    A combined study with use of time-domain pump-probe spectroscopy and time-domain terahertz transmission spectroscopy have been carried out on an underdoped Bi2_2Sr2_2CaCu2_2O8+δ_{8+{\delta}} thin film. It was observed that the low energy multi-excitation states were decomposed into superconducting gap and pseudogap. The pseudogap locally opens below T210T^*{\simeq}210 K simultaneously with the appearance of the high-frequency partial pairs around 1.3 THz. With decreasing temperature, the number of the local domains with the partial phase coherence increased and saturated near 100 K, and the macroscopic superconductivity appeared below 76 K through the superconductivity fluctuation state below 100 K. These experimental results indicate that the pseudogap makes an important role for realization of the superconductivity as a precursor to switch from the partial to the macroscopic phase coherence.Comment: Revtex4, 4 pages, 4 figure

    Ferrimagnetic spin-1/2 chain of alternating Ising and Heisenberg spins in arbitrarily oriented magnetic field

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    The ferrimagnetic spin-1/2 chain composed of alternating Ising and Heisenberg spins in an arbitrarily oriented magnetic field is exactly solved using the spin-rotation transformation and the transfer-matrix method. It is shown that the low-temperature magnetization process depends basically on a spatial orientation of the magnetic field. A sharp stepwise magnetization curve with a marked intermediate plateau, which emerges for the magnetic field applied along the easy-axis direction of the Ising spins, becomes smoother and the intermediate plateau shrinks if the external field is tilted from the easy-axis direction. The magnetization curve of a polycrystalline system is also calculated by performing powder averaging of the derived magnetization formula. The proposed spin-chain model brings an insight into high-field magnetization data of 3d-4f bimetallic polymeric compound Dy(NO_3)(DMSO)_2Cu(opba)(DMSO)_2, which provides an interesting experimental realization of the ferrimagnetic chain composed of two different but regularly alternating spin-1/2 magnetic ions Dy^{3+} and Cu^{2+} that are reasonably approximated by the notion of Ising and Heisenberg spins, respectively.Comment: 11 pages, 6 figure
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