25,585 research outputs found

    X-Ray Evidence of an AGN in M82

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    An X-ray spectrum of the famous starburst galaxy M82 consists of three components: soft, medium, and hard components (Tsuru et al. 1997). The spectrum of the hard component, which is spatially unresolved, is well represented by an absorbed thermal bremsstrahlung, or an absorbed power-law model. However the origin of the hard component was unclear. Thus, we made a monitoring observation with ASCA in 1996. Although the X-ray flux of the soft and medium components remained constant, a significant time variability of the hard component was found between 3×10403\times10^{40} erg/s and 1×10411\times10^{41} erg/s at various time scales from 10 ks to a month. The temperature or photon index of the hard component also changed. We proved that the spatial position of the hard component is the center of M82. The spectrum of the variable source obtained by subtracting the spectrum of the lowest state from the highest state suggests the strong absorption of NH1022N_{\rm H} \sim 10^{22} cm2^2, which means the variable source is embedded in the center of M82. All these suggest that a low-luminosity AGN exists in M82.Comment: 15pages for text and tables. 13pages for figure

    Self-compensating solenoid valve

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    A solenoid valve is described in which both an inlet and an outlet of the valve are sealed when the valve is closed. This double seal compensates for leakage at either the inlet or the outlet by making the other seal more effective in response to the leakage and allows the reversal of the flow direction by simply switching the inlet and outlet connections. The solenoid valve has a valve chamber within the valve body. Inlet and outlet tubes extend through a plate into the chamber. A movable core in the chamber extends into the solenoid coil. The distal end of the core has a silicone rubber plug. Other than when the solenoid is energized, the compressed spring biases the core downward so that the surface of the plug is in sealing engagement with the ends of the tubes. A leak at either end increases the pressure in the chamber, resulting in increased sealing force of the plug

    Desingularization of complex multiple zeta-functions

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    Generalized β\beta-conformal change and special Finsler spaces

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    In this paper, we investigate the change of Finslr metrics L(x,y)Lˉ(x,y)=f(eσ(x)L(x,y),β(x,y)),L(x,y) \to\bar{L}(x,y) = f(e^{\sigma(x)}L(x,y),\beta(x,y)), which we refer to as a generalized β\beta-conformal change. Under this change, we study some special Finsler spaces, namely, quasi C-reducible, semi C-reducible, C-reducible, C2C_2-like, S3S_3-like and S4S_4-like Finsler spaces. We also obtain the transformation of the T-tensor under this change and study some interesting special cases. We then impose a certain condition on the generalized β\beta-conformal change, which we call the b-condition, and investigate the geometric consequences of such condition. Finally, we give the conditions under which a generalized β\beta-conformal change is projective and generalize some known results in the literature.Comment: References added, some modifications are performed, LateX file, 24 page

    Incommensurate magnetism in cuprate materials

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    In the low doping region an incommensurate magnetic phase is observed in LSCO. By means of the composite operator method we show that the single-band 2D Hubbard model describes the experimental situation. In the higher doping region, where experiments are not available, the incommensurability is depressed owing to the van Hove singularity near the Fermi level. A proportionality between the incommensurability amplitude and the critical temperature is predicted, suggesting a close relation between superconductivity and incommensurate magnetism.Comment: 4 pages, 5 figures in one Postscript file, RevTe

    Fundamentals of p-adic multiple L-functions and evaluation of their special values

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    Universal entanglement concentration

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    We propose a new protocol of \textit{universal} entanglement concentration, which converts many copies of an \textit{unknown} pure state to an \textit{% exact} maximally entangled state. The yield of the protocol, which is outputted as a classical information, is probabilistic, and achives the entropy rate with high probability, just as non-universal entanglement concentration protocols do. Our protocol is optimal among all similar protocols in terms of wide varieties of measures either up to higher orders or non-asymptotically, depending on the choice of the measure. The key of the proof of optimality is the following fact, which is a consequence of the symmetry-based construction of the protocol: For any invariant measures, optimal protocols are found out in modifications of the protocol only in its classical output, or the claim on the product. We also observe that the classical part of the output of the protocol gives a natural estimate of the entropy of entanglement, and prove that that estimate achieves the better asymptotic performance than any other (potentially global) measurements.Comment: Revised a lot, especially proofs, though no change in theorems, lemmas itself. Very long, but essential part is from Sec.I to Sec IV-C. Some of the appendces are almost independent of the main bod

    Sunlight supply and gas exchange systems in microalgal bioreactor

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    The bioreactor with sunlight supply system and gas exchange systems presented has proved feasible in ground tests and shows much promise for space use as a closed ecological life support system device. The chief conclusions concerning the specification of total system needed for a life support system for a man in a space station are the following: (1) Sunlight supply system - compactness and low electrical consumption; (2) Bioreactor system - high density and growth rate of chlorella; and (3) Gas exchange system - enough for O2 production and CO2 assimilation
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