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931.
Marc Baguelin Jacques LeFèvre Jean-Pierre Richard 《Journal of Computational and Applied Mathematics》2007
In many problems coming from the “complexity sciences”, the presence of high-dimensional state spaces and non-linear equations renders traditional mathematical objects useless. To deal with these issues, several approaches have recently been studied, most of them presenting the particularity of splitting the dynamical events in two categories; an upper level in which the events describe how the structure of the system changes (the meta-dynamics) and a lower level with the events describing the evolution of the elements in the structure (the dynamics). The state space is then not defined in extenso but unfolds or contracts during the evolution of the system. In term of simulation, this view allows us to deal with only a small part of the state space at each step avoiding the time and memory limitations. 相似文献
932.
Jérôme Dedecker Florence Merlevède Dalibor Volný 《Journal of Theoretical Probability》2007,20(4):971-1004
In this paper we study the central limit theorem and its weak invariance principle for sums of non-adapted stationary sequences,
under different normalizations. Our conditions involve the conditional expectation of the variables with respect to a given
σ-algebra, as done in Gordin (Dokl. Akad. Nauk SSSR 188, 739–741, 1969) and Heyde (Z. Wahrsch. verw. Gebiete 30, 315–320, 1974). These conditions are well adapted to a large variety of examples, including linear processes with dependent innovations
or regular functions of linear processes. 相似文献
933.
P. L. Hanselaer W. H. Laflère R. L. Van Meirhaeghe F. Cardon 《Applied Physics A: Materials Science & Processing》1986,39(2):129-133
In this paper, the influence of two pre-evaporation surface treatments on the electrical characteristics of n- and p-Si/Au, Cr and Ti MIS diodes are studied. A strong dependence of the barrier height on the pre-evaporation treatment is observed and is found to be independent of the metal work function. In order to explain this, it is suggested that the interfacial charges are strongly affected by the pre-evaporation treatment used. 相似文献
934.
935.
Éric Dumas 《Journal of Differential Equations》2005,219(2):484-509
Maxwell-Bloch equations describe the propagation of an electromagnetic wave through a quantum medium. For any number of quantum levels, in space dimension 3, we show the global existence of weak (L2) solutions to the initial-value problem. In the case of smoother electromagnetic fields (with curl in L2), the solution is unique. For smooth data (Hs, s?2), the solutions remain smooth for all times. 相似文献
936.
Salima Saïdi Frdric Guittard Claude Guimon Serge Gribaldi 《Journal of polymer science. Part A, Polymer chemistry》2005,43(17):3737-3747
A series of polyacrylate monomers with F‐alkylalkyl [F(CF2)n(CH2)n′] side groups were prepared by free‐radical polymerization. The effect of the chemical structure on the surface properties of poly(ethylene terephthalate)s was evaluated by variations in the relative length of the fluorocarbon and hydrocarbon units in the side group. The resulting polymers were quite surface‐active in the solid state. The surface and bulk organization was investigated by X‐ray photoelectron spectroscopy analysis. A strong correlation between the bulk organization and surface properties of the polymers was established. The outmost layer, formed from trifluoromethyl groups and some ester functions, suggests that the side chain is arranged irregularly in the polymer–air interface. The length of the lateral chain governs this organization: long fluorinated chains and short hydrocarbon spacers are essential elements of the molecular design for such low‐surface‐energy materials. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 3737–3747, 2005 相似文献
937.
Spencer Bloch Hélène Esnault Dirk Kreimer 《Communications in Mathematical Physics》2006,267(1):181-225
The appearance of multiple zeta values in anomalous dimensions and β-functions of renormalizable quantum field theories has given evidence towards a motivic interpretation of these renormalization group functions. In this paper we start to hunt the motive, restricting our attention to a subclass of graphs in four dimensional scalar field theory which give scheme independent contributions to the above functions. 相似文献
938.
939.
Cécile Machut-Binkowski Frédéric Hapiot Roméo Cecchelli Patrick Martin Eric Monflier 《Journal of inclusion phenomena and macrocyclic chemistry》2007,57(1-4):567-572
For many commercial drugs, reaching the central nervous system in large amount without damaging the blood-brain-barrier (BBB)
remains a challenging task. We present here a supramolecular strategy aiming at using a well-defined cyclodextrin-coated liposomes
as drug carrier and adamantoyl saccharides as BBB-interacting ligands. In this study, the liposome is constituted of n-alkyldimethylammoniumcyclodextrins incorporated in the lipid bilayer of a 3/7 cholesterol/dipalmitoylphosphatidylcholine
mixture and the ligand is constituted of an adamantoylglucose molecule whose adamantoyl moiety can be included in the CD cavity.
The whole supramolecular assembly has been characterized by light-scattering and 31P NMR measurements. Toxicity and permeability studies on an in vitro model of the BBB clearly demonstrated a 5-fold improved
ability of the modified liposome to enter the BBB-endothelial cells compared to the non-coated liposome. Fluorescence labelling
of these liposomes is also displayed with DiI as a fluorescent probe. 相似文献
940.
Ilyes Jedidi Zohra Ferhat‐Hamida Geneviève Delmas 《Journal of Polymer Science.Polymer Physics》2007,45(15):1932-1949
A linear Union Carbide PE (UC) has been analyzed by nonstandard calorimetry with a common DSC calorimeter and a Setaram C80 calorimeter. Nonstandard calorimetry entails using a low rate of heating (0.5–1 K/min), a small mass (0.5–1.5 mg), and an open cell (O‐cell) instead of the standard C‐cell. Events in O‐cells overlap less and occur with a faster kinetics than in C‐cells. PE crystals are nascent, solution‐grown (S‐grown), press‐grown (P‐grown), and strained by extrusion. In Part A, the traces show that the phase‐changes in the melt, previously observed in a C80 calorimeter (slow T‐ramp) and characterized by ΔHnetwork, can be observed with a common DSC in nonstandard conditions. In Part B, the difference between the C‐ and O‐cells and the changes in the main peak enthalpy (ΔHortho) are of interest. The main result is that, in O‐cells, the value of ΔHortho around Tortho, exceeds unambiguously in certain conditions ΔHortho found for perfect orthorhombic crystals. The main endotherm contains then another contribution, namely ΔHnetwork. Crystal reorganization during the slow T‐ramp is followed in the C‐ and O‐cells on S‐grown crystals. In O‐cells, lamellar thickening observed in the slow‐ramp is more extensive. The ease of phase‐change depends on the sample history. It is as follows: strained‐part extruded > nascent > S‐grown > P‐grown. Co‐operative chain motions are more hindered in the standard C‐cells than in the O‐cells. In Part C, lower values of m succeed in bringing phase‐changes in P‐grown (O‐cells) samples. The origin of the events is discussed: three processes are thought to contribute to the phase‐changes namely, melting of strained short‐range order, activation of vibrations in the CH2 groups, and fast decay of chain orientation which occurs simultaneously with melting. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 1932–1949, 2007 相似文献