Halométallates de viologène, état de charge séparé photo-induit stable: quelques paramètres clés

Date du colloque : 06/2011</p

Alien Registration- Leblanc, Alexena N. (Ashland, Aroostook County)

https://digitalmaine.com/alien_docs/27387/thumbnail.jp

“When You Fail, You Feel Like a Failure” : One Student’s Experience of Academic Probation and an Academic Support Program

This in-depth, qualitative study explored the experience of academic probation. It recounts the story of Mark, an undergraduate student on academic probation who participated in an academic support program to attain good academic standing. His story is contrasted to the current literature on academic probation and is considered in light of Dewey’s (1958,1938/1997, 1934/2005) theory of experience. This paper offers an important contribution to the literature on higher education by revealing a rich, complex, and unique experience which illustrates that Mark does not correspond to the typical image of probationary students depicted in the literature. This article breaks away from an oversimplified portrayal of probationary students, offers a provisional conceptualization of academic probation, and calls for further definition of the notion of academic probation. Cette étude qualitative et détaillée a porté sur l’expérience de la probation académique. Elle évoque l’histoire de Mark, un étudiant du premier cycle en probation académique qui a participé à un programme d’appui académique en vue d’améliorer son rendement. Nous comparons son histoire à la littérature actuelle sur la probation académique et l’examinons à la lumière de la théorie de l’expérience de Dewey (1958; 1938/1997; 1934/2005). Cet article représente une contribution importante à la littérature sur l’enseignement supérieur en décrivant une expérience riche, complexe et unique qui démontre que Mark ne correspond pas à l’image type des étudiants en probation tel qu’illustrée dans la littérature. Cet article s’éloigne de la représentation exagérément simplifiée des étudiants en probation, offre une conceptualisation provisoire de la probation académique et évoque le besoin d’une nouvelle définition de la notion de la probation académique

Stable Photoinduced Separated Charge State in Viologen Halometallates: Some Key Parameters

With the aim to define key parameters causing the photochromic properties of (MV)[Bi2Cl8] and (MV)(4)[Bi6Cl26] (MV2+, methylviologen; 1,1-dimethyl-4,4-bipyridinium), the effects of substituting Bi by Sb, Cl by Br, or MV2+ by MOV2+ (1,1-dimethoxy-4,4-bipyridinium) or MeMOV2+ (1-methyl-1-methoxy-4,4-bipyridinium) on the photoinduced charge transfer properties of such viologen halometallates are explored. It appears that only salts containing chlorobismuthate anions undergo a color change upon UV irradiation and that the nature of viologen entities has a key role in the process. We also suggest that a key parameter for observing the stable photoinduced separated charge state in chlorobismuthate viologen hybrids is a high chloride/viologen ratio, rather than the size of the anionic oligomer, as observed in the previously reported unique series (MV)((2n+2)/2)[Bi2nCl8n+2]

Monolithic InP-Based Grating Spectrometer for Wavelength-Division Multiplexed Systems at 1.5 μm

A monolithic InP-based grating spectrometer for use in wavelength-division multiplexed systems at 1.5 μm is reported. The spectrometer uses a single etched reflective focusing diffraction grating and resolves >50 channels at 1 nm spacing with a ~0.3nm channel width and at least 19dB channel isolation. Operation is essentially of the state of the input polarisation

In vivo nuclear magnetic resonance imaging

A number of physiological changes have been demonstrated in bone, muscle and blood after exposure of humans and animals to microgravity. Determining mechanisms and the development of effective countermeasures for long duration space missions is an important NASA goal. The advent of tomographic nuclear magnetic resonance imaging (NMR or MRI) gives NASA a way to greatly extend early studies of this phenomena in ways not previously possible; NMR is also noninvasive and safe. NMR provides both superb anatomical images for volume assessments of individual organs and quantification of chemical/physical changes induced in the examined tissues. The feasibility of NMR as a tool for human physiological research as it is affected by microgravity is demonstrated. The animal studies employed the rear limb suspended rat as a model of mucle atrophy that results from microgravity. And bedrest of normal male subjects was used to simulate the effects of microgravity on bone and muscle

A/r/cography: art, research and communication

This article aims at establishing the foundations for a/r/cography as an “art and communication”-based research methodology, inspired by a/r/tography yet more encompassing, and particularly suitable for the digital art world. As part of the larger family of practice-based research methodologies, a/r/tography presents various ways through which it can be explored, but since it is aimed at the arts and education, its scope is forcibly hampered by the fact that not all researchers and art practitioners are necessarily teachers. However, since most of its underlying principles can be extended for non-teachers, thus arose the idea to propose a methodology that would retain ontological, epistemological and methodological assumptions, but would expand beyond the limitations imposed by the role of the teacher. This extension is called a/r/cography and is structured upon the interchangeable roles of artist, researcher and communicator, as being intrinsic to the underlying living inquiry processes. Furthermore, this proposal is supported by the author’s own experience from a/r/cographic processes in the creation, exhibition and communication of digital artworks.info:eu-repo/semantics/publishedVersio

Extended crossover from Fermi liquid to quasi-antiferromagnet in the half-filled 2D Hubbard model

The ground state of the Hubbard model with nearest-neighbor hopping on the square lattice at half filling is known to be that of an antiferromagnetic (AFM) band insulator for any on-site repulsion. At finite temperature, the absence of long-range order makes the question of how the interaction-driven insulator is realized nontrivial. We address this problem with controlled accuracy in the thermodynamic limit using self-energy diagrammatic determinant Monte Carlo and dynamical cluster approximation methods and show that development of long-range AFM correlations drives an extended crossover from Fermi liquid to insulating behavior in the parameter regime that precludes a metal-to-insulator transition. The intermediate crossover state is best described as a non-Fermi liquid with a partially gapped Fermi surface.Comment: 6 pages, 4 figures, with supplemental material: 2 pages, 3 figure

Fast high-efficiency integrated waveguide photodetectors using novel hybrid vertical/butt coupling geometry

We report a novel coupling geometry for integrated waveguide photodetectors−a hybrid vertical coupling/butt coupling scheme that allows the integration of fast, efficient, photodetectors with conventional double heterostructure waveguides. It can be employed to yield a planar, or pseudo-planar, surface that supports further levels of integration. The approach is demonstrated with a 25-µm-long p-i-n detector integrated with an InP/InGaAsP/InP waveguide, which displays a high (~90%) efficiency and large (~15 GHz) bandwidth. This is the fastest high-efficiency integrated waveguide photodetector reported to date