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In this paper the performance of a fiber-optic LAN with spread spectrum multiplexing is discussed from the viewpoint of transmission parameters. Two architectures are considered. The first concerns a structure with cascade-connected Y-type fiber-optic couplers. The second concerns an architecture with cascade-connected active optoelectronic repeater-coupler (ORCA) devices. 相似文献
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Jacques Bros 《Communications in Mathematical Physics》2003,237(1-2):289-308
It is proved that in any massive relativistic quantum field theory satisfying two-particle asymptotic completeness, all the
bounded energy components in the elastic two-particle range of all subsets of states which are excitations of the vacuum state
by uniformly bounded observables localized in a given finite region of spacetime are compact in the Hilbert space of states.
This result, which is in agreement with Haag-Swieca's conjecture, is also given a more precise form in terms of the rate of
decrease of the ``N–dimensional thickness' (or approximation number) of such sets of states when N tends to infinity. A similar computation, valid at arbitrarily high energies, is also given for the massive free-field case.
Received: 7 February 2003 / Accepted: 5 April 2003
Published online: 13 May 2003
Communicated by H. Araki, D. Buchholz and K. Fredenhagen 相似文献
24.
DEBACHE Abdelmadjid BOULCINA Raouf TAFER Radia BELFAITAH Ali RHOUATI Salah CARBONI Bertrand 《中国化学》2008,26(11):2112-2116
The synthesis of 1,2,3,4-dihydropyrimidinone/thione derivatives was achieved in good to excellent yields using calcium(II) nitrate as catalyst to promote the Biginelli three-component condensation reaction from a diversity of aromatic aldehydes, β-keto compounds and urea or thiourea. The reaction was carried out under solvent-free conditions. 相似文献
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The flat rank of a totally disconnected locally compact group G, denoted flat-rk(G), is an invariant of the topological group
structure of G. It is defined thanks to a natural distance on the space of compact open subgroups of G. For a topological
Kac-Moody group G with Weyl group W, we derive the inequalities alg-rk(W) ≤ flat-rk(G) ≤ rk(|W|0). Here, alg-rk(W) is the maximal Z-rank of abelian subgroups of W, and rk(|W|0) is the maximal dimension of isometrically embedded flats in the CAT0-realization |W|0. We can prove these inequalities under weaker assumptions. We also show that for any integer n ≥ 1 there is a simple, compactly
generated, locally compact, totally disconnected group G, with flat-rk(G) = n and which is not linear. 相似文献
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Dominique Margelin Anny Fourtanier Thierry Thevenin Chantal Medaisko Monique Breton Jacques Picard 《Photochemistry and photobiology》1993,58(2):211-218
Abstract— The effect of UVB exposure on the distribution and synthesis of dermal proteoglycans was measured in the skin of hairless mice. Two groups of mice were included: one was irradiated for 10 weeks; the other was kept as control. After intraperitoneal injection of sodium 35 S-sulfate, punch biopsies were taken for histology and proteoglycans were extracted from the remaining skin with 4 M guanidinium chloride, containing 3–[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate (0.5%, weight per volume). Following proteolytic digestion, the glycosaminoglycan constituents were isolated and analyzed by quantitative cellulose acetate electrophoresis and enzymatic digestibility.
Under the influence of UVB radiation, newly synthesized proteoglycans measured by35 SO4 uptake increased as much as 60%. In addition, the irradiated skin had a higher average content of proteoglycan than had control skin (4981 μg vs 4134 μg/g dry weight). This could be ascribed to an increase in heparin (1400 vs 533 μ g/g dry weight) and heparan sulfate (472 vs 367 μg/g dry weight), whereas no change in the concentration of hyaluronic acid (1243 vs 1372 μg/g dry weight) and dermatan sulfate (1866 vs 1863 μg/g dry weight) was observed. The irradiated animals also exhibited a marked increase in the synthesis of heparan sulfate and heparin (62% and 71%, respectively). These results demonstrate that chronic doses of UVB altered proteoglycan metabolism through both quantitative and qualitative changes. 相似文献
Under the influence of UVB radiation, newly synthesized proteoglycans measured by
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