48 resultados para 7809
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"March 1975."
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We study absorption spectra and two photon absorption coefficient of expanded porphyrins (EPs) by the density matrix renormalization group (DMRG) technique. We employ the Pariser-Parr-Pople (PPP) Hamiltonian which includes long-range electron-electron interactions. We find that, in the 4n+2 EPs, there are two prominent low-lying one-photon excitations, while in 4n EPs, there is only one such excitation. We also find that 4n+2 EPs have large two-photon absorption cross sections compared to 4n EPs. The charge density rearrangement in the one-photon excited state is mostly at the pyrrole nitrogen site and at the meso carbon sites. In the two-photon states, the charge density rearrangement occurs mostly at the aza-ring sites. In the one-photon state, the C-C bond length in aza rings shows a tendency to become uniform. In the two-photon state, the bond distortions are on C-N bonds of the pyrrole ring and the adjoining C-C bonds which connect the pyrrole ring to the aza or meso carbon sites.
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A presente dissertação tem como objetivo investigar a relação entre a disseminação de uma cultura carnavalesca de rua e sua articulação com conceitos relativos à memória em um contexto descrito por diversos autores como sendo de crise. Para tanto, buscou-se uma historicidade acerca das manifestações carnavalescas, sua relação com órgãos de poder e Estado e os dinamismos que representam, frente a outras expressões do carnaval. Sabendo que a realização do carnaval está diretamente relacionada a um dado contexto, buscamos, a partir do conceito de globalização, compreender como esta impacta em uma festividade compreendida como uma cultura local e se firma como uma tradição da cidade do Rio de Janeiro. Para tanto, analisamos as diversas representações desta festividade de rua a partir de uma análise do jornal O Globo durante três anos, isto é, 1993, 2003 e 2013, tendo como hipótese que, o carnaval de rua, em suma, é apresentado como uma expressão cultural oposta ao Desfile das Escola de Samba da Sapucaí, legitimado historicamente como o maior carnaval do Brasil.
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<正>高超声速的英文名称hypersonic,是钱学森先生1946年命名的。由于洲际导弹、卫星、飞船、航天飞机以及当前国际上十分关心的各种高超声速飞行器的研制需要,过去的半个多世纪,世界大国纷纷投入力量开展高超声速流动研究,使其成为最为活跃的力学研究领域之一。
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200 GeV corresponding to baryon chemical potentials (mu(B)) between 200 and 20 MeV. Our measurements of the products kappa sigma(2) and S sigma, which can be related to theoretical calculations sensitive to baryon number susceptibilities and long-range correlations, are constant as functions of collision centrality. We compare these products with results from lattice QCD and various models without a critical point and study the root s(NN) dependence of kappa sigma(2). From the measurements at the three beam energies, we find no evidence for a critical point in the QCD phase diagram for mu(B) below 200 MeV.
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Facilitated alkali metal ion (M+= Li+, Na+, K+, Rb+, and Cs+) transfers across the micro- and nano-water/1,2-dichloroethane (W/DCE) interfaces supported at the tips of micro- and nanopipets by dibenzo-18-crown-6 (DB18C6) have been investigated systematically using cyclic voltammetry. The theory developed by Matsuda et al. was applied to estimate the association constants of DB18C6 and M+ in the DCE phase based on the experimental voltammetric results. The kinetic measurements for alkali metal ion transfer across the W/DCE interface facilitated by DB18C6 were conducted using nanopipets or-submicropipets, and the standard rate constants (k(0)) were evaluated by analysis of the experimental voltammetric data. They increase in the following order: k(Cs+)(0) < k(Li+)(0) < k(Rb+)(0) < k(Na+)(0) < k(K+)(0), which is in accordance with their association constants except Cs+ and Li+.
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Este texto es una reflexión sobre la forma en la que se pide a los estudiantes que aprendan y memoricen que ángulos son iguales cuando dos rectas paralelas son cortadas por una transversal.
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abstract : Taking as a starting point the association between embroidery and language conveyed by the Greek myth of Filomela and Procne, this article examines the relationship between social status and ornaments like embroidery and lace. In order to illustrate this relationship an example is selected form the letters exchanged between the Marquise of Alorna and her Father where a connection is established between the production of these 'feminine' crafts, women's culture and womens writing, in the XVIIIth Century
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1905/10/26 (Numéro 7809).
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Colbertinus