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61.
Antoine Gloria Stefan Neukamm 《Annales de l'Institut Henri Poincaré (C) Analyse Non Linéaire》2011,28(6):941
We prove under some general assumptions on elastic energy densities (namely, frame indifference, minimality at identity, non-degeneracy and existence of a quadratic expansion at identity) that homogenization and linearization commute at identity. This generalizes a recent result by S. Müller and the second author by dropping their assumption of periodicity. As a first application, we extend their Γ-convergence commutation diagram for linearization and homogenization to the stochastic setting under standard growth conditions. As a second application, we prove that the Γ-closure is local at identity for this class of energy densities. 相似文献
62.
Tan B Hernández-Torres G Barbas CF 《Journal of the American Chemical Society》2011,133(32):12354-12357
Carbazolespirooxindole derivatives were synthesized in a high-yielding, atypically rapid, stereocontrolled Diels-Alder reaction catalyzed by a C(2)-symmetric bisthiourea organocatalyst. Simple precursors and mild conditions were used to construct carbazolespirooxindole derivatives with high enantiopurity and structural diversity under H-bonding catalysis. The practical approach recycles the organocatalyst and solvent. This simple and efficient operational procedure will allow diversity-oriented syntheses of this intriguing class of compounds. 相似文献
63.
Maurelli S Vishnuvarthan M Chiesa M Berlier G Van Doorslaer S 《Journal of the American Chemical Society》2011,133(19):7340-7343
The incorporation of Ti ions within the framework of aluminophosphate zeotype AlPO-5 and their chemical reactivity is studied by means of CW-EPR, HYSCORE, and UV-vis spectroscopies. Upon reduction, Ti(3+) ions are formed, which exhibit large (31)P hyperfine couplings, providing direct evidence for framework substitution of reducible Ti ions at Al sites. 相似文献
64.
Structural and spectroscopic investigation of ZnS nanoparticles grown in quaternary reverse micelles 总被引:1,自引:0,他引:1
Manyar HG Iliade P Bertinetti L Coluccia S Berlier G 《Journal of colloid and interface science》2011,354(2):511-516
ZnS nanoparticles were synthesized in four component "water in oil" microemulsions formed by a cationic surfactant (cetyltrimethylammonium bromide, CTAB), a cosurfactant (pentanol or butanol), n-hexane and water. The effect of various parameters (nature of cosurfactant, water/surfactant W(0), and alcohol/surfactant P(0)) on the formation and stability of ZnS nanoparticles was investigated thoroughly. UV-Vis spectroscopy was employed to directly follow the formation of ZnS systems in the microemulsions. Thus, particle size was estimated from the position of the first excitonic transition by employing an approximate finite-depth equation and an empirical correlation, giving average diameters in the ranges 2.3-2.5 and 3.0-3.5nm, respectively. Stable ZnS nanoparticles were obtained by employing low water and high cosurfactant amounts. This suggests that at high concentration the cosurfactant molecules act as capping agents on the surface of the inverse micelles, while low water amounts are needful to obtain water droplets with a radius close to that of the interfacial film spontaneous curvature. HRTEM analysis showed that the samples are formed by a few crystalline ZnS nanoparticles of spherical shape, embedded in and amorphous organic matrix, with a coherent scattering domain between 2 and 4nm. 相似文献
65.
de los Santos JM Ignacio R Rubiales G Aparicio D Palacios F 《The Journal of organic chemistry》2011,76(16):6715-6725
Phosphorylated nitroso alkenes react with cyclic dienes such as cyclopentadiene or cyclohexadiene to afford hetero Diels-Alder-type cycloadducts where the nitroso alkene participates as dienophile component and the cyclic olefin acts as the 4π-electron (diene) system. Subsequent aza-Cope rearrangement affords highly functionalized 5,6-dihydro-4H-1,2-oxazines. Conversely, the reaction of TMS-substituted cyclopentadiene (dienophile) with nitroso alkenes as heterodienes leads directly to bicyclic 1,2-oxazines. Theoretical studies are in agreement with the experimental results and with the new aza-Cope rearrangement proposed. 相似文献
66.
Quality control is an important and integral part to any microfabrication process. While the widths of features often can be easily assessed by light microscopy, the heights of the fabricated structures are more difficult to determine. Here, we present a rapid, accurate, and low-cost method to measure the heights of microfabricated structures during and after the fabrication process. This technique is based on white-light interferometry, which offers accuracy on the submicrometre scale. 相似文献
67.
Roberto Alicandro Marco Cicalese Antoine Gloria 《Archive for Rational Mechanics and Analysis》2011,200(3):881-943
This article is devoted to the study of the asymptotic behavior of a class of energies defined on stochastic lattices. Under
polynomial growth assumptions, we prove that the energy functionals Fe{F_\varepsilon} stored in the deformation of an e{{\varepsilon}}-scaling of a stochastic lattice Γ-converge to a continuous energy functional when e{{\varepsilon}} goes to zero. In particular, the limiting energy functional is of integral type, and deterministic if the lattice is ergodic.
We also generalize, to systems and nonlinear settings, well-known results on stochastic homogenization of discrete elliptic
equations. As an application of the main result, we prove the convergence of a discrete model for rubber towards the nonlinear
theory of continuum mechanics. We finally address some mechanical properties of the limiting models, such as frame-invariance,
isotropy and natural states. 相似文献
68.
Georgiana Dascalu Gloria Pompilian Bertrand Chazallon Valentin Nica Ovidiu Florin Caltun Silviu Gurlui Cristian Focsa 《Applied Physics A: Materials Science & Processing》2013,110(4):915-922
CoFe2O4 thin films with preferential texture structure, small grain size, and perpendicular magnetic anisotropy can be obtained by the pulsed laser deposition (PLD) technique. In this work, we studied the influence of the Fe3+ ions substitution by three elements from lanthanide group (Dy, La, and Gd) on the structural properties of the thin films. The samples were deposited by Nd:YAG laser (λ=532 nm, 10 ns) ablation of CoFe1.8RE0.2O4, (RE=Dy, La, Gd) targets at various substrate temperatures ranging from room temperature to 600 °C. The microstructure and chemical composition of the thin films were investigated by Raman spectroscopy, XRD, SEM-EDS, and ToF-SIMS. The XRD patterns and Raman spectra of the thin films indicated the formation of a single spinel structure. Thus, the desired substitution of the iron ions in the spinel lattice with the RE elements was achieved in the thin films, although in the bulk material, their presence determined the formation of a residual phase with a perovskite-type structure. 相似文献
69.
Narjès Bellamine-Ben Saoud Gloria Mark 《Computational & Mathematical Organization Theory》2007,13(2):113-146
In this paper, we investigate how complexity theory can benefit collaboration by applying an agent-based computer simulation
approach to a new form of synchronous real-time collaborative engineering design. Fieldwork was conducted with a space mission
design team during their actual design sessions, to collect data on their group conversations, team interdependencies, and
error monitoring and recovery practices. Based on the fieldwork analysis, an agent-based simulator was constructed. The simulation
shows how error recovery and monitoring is affected by the number of small group, or sidebar, conversations, and consequent
noise in the room environment. This simulation shows that it is possible to create a virtual environment with cooperating
agents interacting in a dynamic environment. This simulation approach is useful for identifying the best scenarios and eliminating
potential catastrophic combinations of parameters and values, where error recovery and workload in collaborative engineering
design could be significantly impacted. This approach is also useful for defining strategies for integrating solutions into
organizations.
Narjès Bellamine-Ben Saoud is an Associate Professor at the University of Tunis and Researcher at RIADI-GDL Laboratory, Tunisia. After Computer Science
engineering diploma (1993) of the ENSEEIHT of Toulouse, France, she received her PhD (1996), on groupware design applied to
the study of cooperation within a space project, from the University of Toulouse I, France. Her main research interests concern
studying complex systems particularly by modeling and simulating collaborative and socio-technical systems; developing Computer
Supported Collaborative Learning in tunisian primary schools; and Software Engineering. Her current reserach projects include
modeling and simulation of emergency rescue activities for large-scale accidents, modeling of epidemics and study of malaria,
simulation of collabration artifacts.
Gloria Mark is an Associate Professor in the Department of Informatics, University of California, Irvine. Dr. Mark received her Ph.D.
in Psychology from Columbia University in 1991. Prior to UCI, she was a Research Scientist at the GMD, in Bonn, Germany, a
visiting research scientist at the Boeing Company, and a research scientist at the Electronic Data Systems Center for Advanced
Research. Dr. Mark’s research focuses on the design and evaluation of collaborative systems. Her current projects include
studying worklife in the network-centric organization, multi-tasking of information workers, nomad workers, and a work in
a large-scale medical collaboratory. Dr. Mark is widely published in the fields of CSCW and HCI, is currently the program
co-chair for the ACM CSCW’06 conference and is on the editorial board of Computer Supported Cooperative Work: The Journal
of Collaborative Computing, and e-Service Qu@rterly. 相似文献
70.
A homogeneous TiO2 gel was obtained by hydrolysing titanium(IV) isopropoxide that was previously modified by reaction with acetic acid. The so stabilized precursor was hydrolysed under strong acidic medium (pH=0 by HCl). Dried TiO2 powders were characterized by FT-IR, XRD, N2 adsorption analyses, coupled thermogravimetric (TG) gas chromatographic (GC) and `mass spectrometric (MS) analyses. A semiquantitative analysis of the main evolved chemical species allowed to depict both the chemical rearrangements occurring in the TiO2 matrix during pyrolysis and the chemical composition of the initial gel.This revised version was published online in November 2005 with corrections to the Cover Date. 相似文献