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Search Results: 1 - 10 of 3987 matches for " Alain Fave "
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TEM and STEM Observations of a Flat Continuous Silicon-Germanium Thin Film Epitaxially Grown on Porous Silicon  [PDF]
Junji Yamanaka, Noritaka Usami, Sevak Amtablian, Alain Fave, Mustapha Lemiti, Chiaya Yamamoto, Kiyokazu Nakagawa
Journal of Materials Science and Chemical Engineering (MSCE) , 2017, DOI: 10.4236/msce.2017.51004
Strain-relaxed SiGe is an attractive material for use as a substrate of strained Si, in which carrier mobility is higher than that of bulk Si. The concept of this study is the use of porous Si as a sponge like substrate so that a SiGe lattice can relax without introducing dislocations. We produced porous Si specimens by electrochemical anodization and annealed them under a H2 atmosphere. Then, SiGe thin films were grown by gas-source molecular beam epitaxy. We observed the microstructure of the specimens using transmission electron microscopy. The result showed that we succeeded in producing a single-crys- tal continuous Si0.73Ge0.27 film with a 10% relaxation ratio and a low dislocation density on porous Si.
Absorption enhancement in amorphous silicon photonic crystals for thin film photovoltaic solar cells
Ounsi El Daif,Emmanuel Drouard,Yeonsang Park,Alain Fave,Anne Kaminski,Mustapha Lemiti,Xavier Letartre,Pierre Viktorovitch,Sungmo Ahn,Heonsu Jeon,Christian Seassal
Physics , 2009,
Abstract: We report on very high enhancement of thin layer's absorption through band-engineering of a photonic crystal structure. We realized amorphous silicon (aSi) photonic crystals, where slow light modes improve absorption efficiency. We show through simulation that an increase of the absorption by a factor of 1.5 is expected for a film of aSi. The proposal is then validated by an experimental demonstration, showing an important increase of the absorption of a layer of aSi over a spectral range of 0.32-0.76 microns.
Down Converter Device Combining Rare-Earth Doped Thin Layer and Photonic Crystal for c-Si Based Solar Cell
Thierry Deschamps,Emmanuel Drouard,Romain Peretti,Lo?c Lalouat,Erwann Fourmond,Alain Fave,Antoine Guille,António Pereira,Bernard Moine,Christian Seassal
Physics , 2013, DOI: 10.4229/28thEUPVSEC2013-1BO.11.2
Abstract: The aim of the study is to develop ultra-compact structures enabling an efficient conversion of single high energy photon (UV) to two lower energy photons (IR). The proposed structure combines rare-earths doped thin layer allowing the down-conversion process with a photonic crystal (PhC), in order to control and enhance the down-conversion using optical resonances. On the top of the rare-earths doped layer, a silicon nitride (SiN) 2D planar PhC is synthesized. For that, SiN is first deposited by PECVD. After holographic lithography and reactive ion etching, a periodic square lattice of holes is generated on the SiN layer. The PhC topographical parameters as well as the layers thickness are optimized using Finite-Difference-Time-Domain simulations. The design and realization of such PhC-assisted down-converter structures is presented. Optical simulations demonstrate that the PhC leads to the establishment of resonant modes located in the underneath doped layer, allowing a drastic enhancement of the absorption of the rare-earth ions without disturbing the transmission in the visible and near-IR parts of the spectrum, hence demonstrating the relevance of such an approach.
Deficiência, reabilita??o e desenvolvimento do indivíduo: quest?es psicológicas e trans-culturais
Fave, Antonella Delle;
Paidéia (Ribeir?o Preto) , 2001, DOI: 10.1590/S0103-863X2001000200005
Abstract: by means of a ceaseless information exchange with the environment, humans attain progressively higher levels of complexity in behavior. they play an active role in the interaction with their social context, selectively replicating in daily life some cultural information units, in terms of activities, interests, relationships, sources of knowledge. this process has been defined psychological selection and it is guided by the quality pf experience a subject perceives in dealing with environmental information and opportunities for action. optimal experience, or flow, fosters individual development, inducing the subject to look for more and more complex opportunities for action, to face with improving abilities. it contributes to the identification and building of an individual's life theme, which comprises the basic life goals and lifelong targets. this perspective has only recently been adopted in the study of organic and psychic pathology, and even more rarely in the cross-cultural comparison of pathological samples. as concerns disability, studies have emphasized the importance of optimal experience in fostering individual's physical as well as social functioning among blind and paraplegic adult people, as well as among disabled children.
Optimal Experience and Meaning: Which Relationship?
Antonella Delle Fave
Psychological Topics , 2009,
Abstract: A large number of studies conducted in the last twenty years show that optimal experience is a positive and complex condition in which cognitive, motivational and emotional components coexist in a coherent and articulated reciprocal integration. By virtue of its positive psychological features, optimal experience has been sometimes misunderstood as a state which automatically brings about well-being and development. Several studies have disconfirmed this assumption, showing that the outcomes of optimal experience are not automatically positive. Rather, they vary according to the features of the associated activities and to the value system of the cultural environment. Researchers in this domain have been primarily devoted their attention to the structure of the activities that promote optimal experience, and to the goal pursuit they facilitate. Goals are given a prominent role in development in that they provide individuals with practical orientation and purpose in life. But something is missing in this framework: meaning. What do we know about the relationship between optimal experience and meaning making? Based on findings coming from different contexts and cultures, this paper tries to give optimal experience a role within the long-term process of meaning-making.
Living at home or in institution: adolescents' optimal experience and life theme building
Fave, Antonella Delle;Massimini, Fausto;
Paidéia (Ribeir?o Preto) , 2000, DOI: 10.1590/S0103-863X2000000200008
Abstract: the influence of family relationships on adolescents' behavior and development has been widely investigated. this study examines the relationship between family structure and a) adolescents' quality of experience in daily activities and social contexts b) adolescents' perceived life influences, challenges and goals. to achieve this aim, flow questionnaire and life theme questionnaire were administered to 50 italian girls (15-21 years of age), 25 living in two-parent families, 25 entrusted to institutions for custody of minors. the findings suggest tha adolescents' perception of a positive and supportive family enviroment fosters the active search for challenges and enjoyment in daily activities, and the involvement in productive and social contexts. on the contrary , negative family perception is related to lack of engagement and motivation, and to the prevalence of low-challenge activities as sources of enjoyment and satisfaction. although the sample size does not allow us to draw conclusions about causality, the results confirm the crucial role of family in influencing adolescents' psychological and behavioral development.
A simplified picture for Pi electrons in conjugated polymers : from PPP Hamiltonian to an effective molecular crystal approach
S. Pleutin,J. L. Fave
Physics , 1998, DOI: 10.1088/0953-8984/10/18/005
Abstract: An excitonic method proper to study conjugated oligomers and polymers is described and its applicability tested on the ground state and first excited states of trans-polyacetylene, taken as a model. From the Pariser-Parr-Pople Hamiltonian, we derive an effective Hamiltonian based on a local description of the polymer in term of monomers; the relevant electronic configurations are build on a small number of pertinent local excitations. The intuitive and simple microscopic physical picture given by our model supplement recent results, such as the Rice and Garstein ones. Depending of the parameters, the linear absorption appears dominated by an intense excitonic peak.
Molecular crystal approach for pi-conjugated polymers: from PPP Hamiltonian to Holstein model for polaron states
S. Pleutin,J-L Fave
Physics , 1998, DOI: 10.1088/0953-8984/11/48/320
Abstract: Starting from the $\pi$-electron Pariser-Parr-Pople (PPP) Hamiltonian which includes both strong electron-phonon and electron-electron interactions, we propose some strongly correlated wave functions of increasing quality for the ground state of conjugated polymers. These wavefunctions are built by combining different finite sets of local configurations extended at most over two nearest-neighbour monomers. With this picture, the doped case with one additional particle is expressed in terms of quasi-particle. Thus, the polaron formation problem goes back to the study of a Holstein like model.
Carnot Factor of a Vapour Power Cycle with Regenerative Extraction  [PDF]
Duparquet Alain
Journal of Modern Physics (JMP) , 2017, DOI: 10.4236/jmp.2017.811107
Abstract: The present paper describes the energy analysis of a regenerative vapour power system. The regenerative steam turbines based on the Rankine cycle and comprised of vapour extractions have been used industrially since the beginning of the 20th century, particularly regarding the processes of electrical production. After having performed worked in the first stages of the turbine, part of the vapour is directed toward a regenerative exchanger and heats feedwater coming from the condenser. This process is known as regeneration, and the heat exchanger where the heat is transferred from steam is called a regenerator (or a feedwater heater). The profit in the output brought by regenerative rakings is primarily enabled by the lack of exchange of the tapped vapour reheating water with the low-temperature reservoir. The economic optimum is often fixed at seven extractions. One knows the Carnot relation, which is the best possible theoretical yield of a dual-temperature cycle; in a Carnot cycle, one makes the assumption that both compressions and expansions are isentropic. This article studies an ideal theoretical machine comprised of vapour extractions in which each cycle partial of tapped vapour obeys these same compressions and isentropic expansions.
Essay on Playfulness and Play in Children’s Art Class: A Reflection Based on Winnicott  [PDF]
Alain Savoie
Creative Education (CE) , 2019, DOI: 10.4236/ce.2019.102024
Abstract: From a survey of literature, this article presents some reflections about the value of play and playfulness as, respectively, an activity and a creative attitude of mind to be fostered in art education in children. Indeed, at the heart of any artistic creative impulse sits a playful attitude of the artist towards realitya feature that has been highlighted by the psychoanalyst Winnicott. Following his line of thought, we propose that the art teacher must place the learner in a position of being able to play with her/him, in order to overlap their two areas of playing and establish a learning space. Playfulness and play tend to be confused with impulsive and disruptive behaviours and generally more tolerated at home then school. We claim that artistic activities in school should always be play-based and take place in a playful environment because art and creation emerge from and grow in and as play.
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