41,168 research outputs found

    Wet-oxidation waste management system for CELSS

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    A wet oxidation system will be useful in the Closed Ecological Life Support System (CELSS) as a facility to treat organic wastes and to redistribute inorganic compounds and elements. However at rather higher temperatures needed in this reaction, for instance, at 260 deg C, only 80% of organic in a raw material can be oxidized, and 20% of it will remain in the liquid mainly as acetic acid, which is virtually noncombustible. Furthermore, nitrogen is transformed to ammonium ions which normally cannot be absorbed by plants. To resolve these problems, it becomes necessary to use catalysts. Noble metals such as Ru, Rh and so on have proved to be partially effective as these catalysts. That is, oxidation does not occur completely, and the unexpected denitrification, instead of the expected nitrification, occurs. So, it is essential to develop the catalysts which are able to realize the complete oxidation and the nitrification

    Behind the success of the quark model

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    The ground-state three-quark (3Q) potential V3Qg.s.V_{\rm 3Q}^{\rm g.s.} and the excited-state 3Q potential V3Qe.s.V_{\rm 3Q}^{\rm e.s.} are studied using SU(3) lattice QCD at the quenched level. For more than 300 patterns of the 3Q systems, the ground-state potential V3Qg.s.V_{\rm 3Q}^{\rm g.s.} is investigated in detail in lattice QCD with 123×2412^3\times 24 at β=5.7\beta=5.7 and with 163×3216^3\times 32 at β=5.8,6.0\beta=5.8, 6.0. As a result, the ground-state potential V3Qg.s.V_{\rm 3Q}^{\rm g.s.} is found to be well described with Y-ansatz within the 1%-level deviation. From the comparison with the Q-Qˉ\rm\bar Q potential, we find the universality of the string tension as σ3Q≃σQQˉ\sigma_{\rm 3Q}\simeq\sigma_{\rm Q\bar Q} and the one-gluon-exchange result as A3Q≃12AQQˉA_{\rm 3Q}\simeq\frac12 A_{\rm Q\bar Q}. The excited-state potential V3Qe.s.V_{\rm 3Q}^{\rm e.s.} is also studied in lattice QCD with 163×3216^3\times 32 at β=5.8\beta=5.8 for 24 patterns of the 3Q systems.The energy gap between V3Qg.s.V_{\rm 3Q}^{\rm g.s.} and V3Qe.s.V_{\rm 3Q}^{\rm e.s.}, which physically means the gluonic excitation energy, is found to be about 1GeV in the typical hadronic scale, which is relatively large compared with the excitation energy of the quark origin. This large gluonic excitation energy justifies the great success of the simple quark model.Comment: Talk given at 16th International Conference on Particles and Nuclei (PANIC 02), Osaka, Japan, 30 Sep - 4 Oct 200

    Low temperature metallic state induced by electrostatic carrier doping of SrTiO3_3

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    Transport properties of SrTiO3_3-channel field-effect transistors with parylene organic gate insulator have been investigated. By applying gate voltage, the sheet resistance falls below R□R_{\Box} ∼\sim 10 kΩ\Omega at low temperatures, with carrier mobility exceeding 1000 cm2^2/Vs. The temperature dependence of the sheet resistance taken under constant gate voltage exhibits metallic behavior (dRdR/dTdT >> 0). Our results demonstrate an insulator to metal transition in SrTiO3_3 driven by electrostatic carrier density control.Comment: 3 pages, 4 figure

    Checking the transverse Ward-Takahashi relation at one loop order in 4-dimensions

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    Some time ago Takahashi derived so called {\it transverse} relations relating Green's functions of different orders to complement the well-known Ward-Green-Takahashi identities of gauge theories by considering wedge rather than inner products. These transverse relations have the potential to determine the full fermion-boson vertex in terms of the renormalization functions of the fermion propagator. He & Yu have given an indicative proof at one-loop level in 4-dimensions. However, their construct involves the 4th rank Levi-Civita tensor defined only unambiguously in 4-dimensions exactly where the loop integrals diverge. Consequently, here we explicitly check the proposed transverse Ward-Takahashi relation holds at one loop order in dd-dimensions, with d=4+ϵd=4+\epsilon.Comment: 20 pages, 3 figures This version corrects and clarifies the previous result. This version has been submitted for publicatio
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