944 resultados para dichroic mirror


Relevância:

10.00% 10.00%

Publicador:

Resumo:

The magnetic field line structure in a tokamak can be obtained by direct numerical integration of the field line equations. However, this is a lengthy procedure and the analysis of the solution may be very time-consuming. Otherwise we can use simple two-dimensional, area-preserving maps, obtained either by approximations of the magnetic field line equations, or from dynamical considerations. These maps can be quickly iterated, furnishing solutions that mirror the ones obtained from direct numerical integration, and which are useful when long-term studies of field line behavior are necessary (e.g. in diffusion calculations). In this work we focus on a set of simple tokamak maps for which these advantages are specially pronounced.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The absorption threshold in EuTe and EuSe was investigated as a function of applied magnetic field in the Faraday geometry. A well-resolved doublet of sharp dichroic lines was observed when the magnetic field induced ferromagnetic alignment of the spins in the crystal lattice. In contrast, at zero magnetic field only a broad and featureless absorption onset is seen. These results are fully explained in terms of a model of electronic transitions between localized states at the Eu lattice site and a tight-binding conduction band, which incorporates the formation of spin domains. Based on this model, predictions are made concerning the possibility of inducing magnetization of the spin lattices by illuminating the material with circularly polarized light.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

In this work we investigate the dynamical Casimir effect in a nonideal cavity by deriving an effective Hamiltonian. We first compute a general expression for the average number of particle creation, applicable for any law of motion of the cavity boundary, under the only restriction of small velocities. We also compute a general expression for the linear entropy of an arbitrary state prepared in a selected mode, also applicable for any law of motion of a slow moving boundary. As an application of our results we have analyzed both the average number of particle creation and linear entropy within a particular oscillatory motion of the cavity boundary. On the basis of these expressions we develop a comprehensive analysis of the resonances in the number of particle creation in the nonideal dynamical Casimir effect. We also demonstrate the occurrence of resonances in the loss of purity of the initial state and estimate the decoherence times associated with these resonances. Since our results were obtained in the framework of the perturbation theory, they are restricted, under resonant conditions, to a short-time approximation. (C) 2009 Elsevier Inc. All rights reserved.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

In this paper, we analyze the action of the gravitational field on the dynamical Casimir effect. We consider a massless scalar field confined in a cuboid cavity placed in a gravitational field described by a static and diagonal metric. With one of the plane mirrors of the cavity allowed to move, we compute the average number of particles created inside the cavity by means of the Bogoliubov coefficients computed through perturbative expansions. We apply our result to the case of an oscillatory motion of the mirror, assuming a weak gravitational field described by the Schwarzschild metric. The regime of parametric amplification is analyzed in detail, demonstrating that our computed result for the mean number of particles created agrees with specific associated cases in the literature. Our results, obtained in the framework of the perturbation theory, are restricted, under resonant conditions, to a short-time limit.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The fabrication of controlled molecular architectures is essential for organic devices, as is the case of emission of polarized light for the information industry. In this study, we show that optimized conditions can be established to allow layer-by-layer (LbL) films of poly(p-phenylene vinylene) (PPV)+dodecylbenzenesulfonate (DBS) to be obtained with anisotropic properties. Films with five layers and converted at 110 degrees C had a dichroic ratio delta = 2.3 and order parameter r = 34%, as indicated in optical spectroscopy and emission ellipsometry data. This anisotropy was decreased with the number of layers deposited, with delta = 1.0 for a 75-layer LbL PPV + DBS film. The analysis with atomic force microscopy showed the formation of polymer clusters in a random growth process with the normalized height distribution being represented by a Gaussian function. In spite of this randomness in film growth, the self-covariance function pointed to a correlation between clusters, especially for thick films. In summary, the LbL method may be exploited to obtain both anisotropic films with polarized emission and regular, nanostructured surfaces. (c) 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 49: 206-213, 2011

Relevância:

10.00% 10.00%

Publicador:

Resumo:

I denna uppsats har filmljudet i krigsfilmerna Apocalypse Now och Saving Private Ryan undersökts. Detta har gjorts för att försöka bidra med ökad förståelse för filmljudets användningsområde och funktioner, främst för filmerna i fråga, men även för krigsfilm rent generellt. Filmljud i denna kontext omfattar allt det ljud som finns i film, men utesluter dock all ickediegetisk musik. Båda filmerna har undersökts genom en audio-visuell analys. En sådan analys görs genom att detaljgranska båda filmernas ljud- och bildinnehåll var för sig, för att slutligen undersöka samma filmsekvens som helhet då ljudet och bilden satts ihop igen. Den audio-visuella analysmetod som nyttjats i uppsatsen är Michel Chions metod, Masking. De 30 minuter film som analyserades placerades sedan i olika filmljudzoner, där respektive filmljudzons ljudinnehåll bland annat visade vilka främsta huvudfunktioner somfilmljudet hade i dessa filmer. Dessa funktioner är till för att bibehålla åskådarens fokus och intresse, att skapa närhet till rollkaraktärerna, samt att tillföra en hög känsla av realism och närvaro. Intentionerna med filmljudet verkade vara att flytta åskådaren in i filmens verklighet, att låta åskådaren bli ett med filmen. Att återspegla denna känsla av realism, närvaro, fokus samt intresse, visade sig också vara de intentioner som funnits redan i de båda filmernas förproduktionsstadier. Detta bevisar att de lyckats åstadkomma det de eftersträvat. Men om filmljudet använts på samma sätt eller innehar samma funktioner i krigsfilm rent genrellt går inte att säga.I have for this bachelor’s thesis examined the movie sound of the classic warfare movies Apocalypse Now and Saving Private Ryan. This is an attempt to contribute to a more profound comprehension of the appliance and importance of movie sound. In this context movie sound implies all kinds of sounds within the movies, accept from non-diegetic music. These two movies have been examined by an audio-visual analysis. It's done by auditing the sound and picture content separately, and then combined to audit the same sequence as a whole. Michel Chion, which is the founder of this analysis, calls this method Masking. The sound in this 30 minute sequence was then divided into different zones, where every zone represented a certain main function. These functions are provided to create a stronger connection to the characters, sustain the viewers interest and bring a sense of realism and presence. It seems though the intention with the movies sound is to bring the viewers to the scene in hand, and let it become their reality. To mirror this sense of realism, presence, focus and interest, proves to be the intention from an early stage of the production. This bachelor’s thesis demonstrates a success in their endeavours. Although it can’t confirm whether the movie sound have been utilized in the same manner or if they posess the same functions to warefare movies in general.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Two different concentrating mirrors have been constructed that resemble parabolic dish reflectors. Both mirrors are made of slightly curved strips of flat, bendable material. The strips of the most simplified mirror have only large-radius circles and straight lines as boundaries. The necessary equations for making the mirrors have been derived. Also a simple way to make a stiff, lightweight frame and support for the mirror strips has been developed. Models of the mirrors have been built and successfully used for cooking and baking.This report is an extended version of a paper to be published in Solar Energy that contains complete derivations of all mirror design equations.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

This essay is an analysis of the character María Josefa in the play 'The House of Bernarda Alba' (1936) by Federico García Lorca. It is hypothesized that the character of María Josefa can be considered a distorting mirror of the femininity presented in the play, and that through María Josefa this femininity is both revealed and problematized. The analysis adopts theories from the field of the (female) grotesque, using terminology both from Mikhail Bakhtin and Mary Russo. Throughout the analysis it is demonstrated how the character of María Josefa challenges the boundaries and norms which are dictated by Bernarda to control the women of the house. These conventions are challenged by María Josefa with the use of her loud speech, her dressed up appearance, and in her physical resistance. In this manner María Josefa is creating and embodying an alternate feminine view that is uncovered through her consistent provocation and by making herself into "a spectacle", a transboundary behaviour that is well interpreted within the theories of carnival, the grotesque body, and the spectacle of the female grotesque.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The necessary nationalism This article deals with the role of fictional narratives, especially the modern novel, in the formation of national identities. Naguib Mafouz’s Cairo trilogy is referred to as an example of how literature may both serve as the mirror image of national identities and as an agency in their formation. The sense of community attachment to a modern state is ”thinner” than to a family or traditional village and/or tribe, though no less vital. Drawing on Norbert Elias’s concept of ”survival unit,” Benedict Anderson’s ”imagined communities” and recent studies in the field of comparative literature by Gregory Jusdanis and Azade Seyhan, this article argues for the necessity of the nation – in spite of its unfavourable chauvinistic reputation. This contention is discussed in relation to recent literary developments in Turkey and recent debates on nationhood in a Swedish context.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

This thesis explores aspects of teachers’ obligation to implement and discuss what are referred to in the Swedish national school curricula as “fundamental values” (“värdegrunden” in Swedish). The aim is to describe and analyze dilemmas in interpretations of and teachers’ work with these fundamental values. Four questions are related to this aim. The first addresses difficulties discussed in conversations between seven upper secondary teachers, during nine meetings over the course of one year. In these conversations the teachers reflected upon how to interpret the fundamental values in relation to their daily practice. The second question focuses on the considerable diversity of Swedish schools and examines the work of the teachers through a perspective of intersectionality. The third question concerns how Martha Nussbaum’s theory of emotions as judgments of value could be used for an understanding of the identified dilemmas. The fourth question focuses on ways in which the participating teachers’ discussions may contribute to a wider discussion about possible aims and circumstances of teachers’ work with the fundamental values. Chapter 2 introduces the theoretical framework of the study, Martha Nussbaum’s (2001) ethical thinking on emotions as judgments of value. She argues that emotions have four common cognitive components. They have (1) external objects, and are directed towards these objects. They are (2) intentional, reflecting a person’s particular point of view, his or her special way of beholding the object, and (3) consist of judgments, i.e. views of how things in the world are. According to Nussbaum’s Aristotelian ethics, emotions also (4) mirror the individual’s vision of what a good human life is like, and the vulnerability of it. The concept of eudaimonia, a fulfilled or flourishing life, is central. Chapter 3 focuses on ideas of ethnicity, and on the specific obligation mentioned in the curriculum of counteracting xenophobia and intolerance in a multicultural society. Chapter 4 discusses various aspects of the teachers’ thoughts on religiosity within Swedish society (often depicted as one of most secular in the world) and within the educational system that is non-denominational. Chapter 5 draws attention to different ways in which the teachers view and teach pupils about sexual orientation. Chapter 6 presents conclusions on potential advantages of and challenges involved in Nussbaum’s Aristotelian theory of emotions, when applied to teachers’ views of and practical work with the fundamental values described in the curriculum. One advantage is that emotions may be intellectually scrutinized and morally assessed, on grounds that are known beforehand and discussed in a democratic process. The non-productive division between emotions, on the one hand, and intellectual and moral capabilities, on the other, is transcended by Nussbaum’s theory. An important challenge is to reflect upon when to discuss the cognitive content of pupils’ emotions, and when it is appropriate to state what is right or wrong, and try to influence pupils accordingly. Keywords: Emotions, vulnerability, values education, religious education, teaching, Martha Nussbaum, ethnicity, religion, sexual orientation.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

This paper reports a single case of ipsilesional left neglect dyslexia and interprets it according to the three-level model of visual word recognition proposed by Caramazza and Hillis (1990). The three levels reflect a progression from the physical stimulus to an abstract representation of a word. RR was not impaired at the first, retinocentric, level, which represents the individual features of letters within a word according to the location of the word in the visual field: She made the same number of errors to words presented in her left visual field as in her right visual field. A deficit at this level should also mean the patient neglects all stimuli. This did not occur with RR: She did not neglect when naming the items in rows of objects and rows of geometric symbols. In addition, although she displayed significant neglect dyslexia when making visual matching judgements on pairs of words and nonwords, she did not do so to pairs of nonsense letter shapes, shapes which display the same level of visual complexity as letters in words. RR was not impaired at the third, graphemic, level, which represents the ordinal positions of letters within a word: She continued to neglect the leftmost (spatial) letter of words presented in mirror-reversed orientation and she did not neglect in oral spelling. By elimination, these results suggest RR's deficit affects a spatial reference frame where the representational space is bounded by the stimulus: A stimulus-centred level of representation. We define five characteristics of a stimulus-centred deficit, as manifest in RR. First, it is not the case that neglect dyslexia occurs because the remaining letters in a string attract or capture attention away from the leftmost letter(s). Second, the deficit is continuous across the letter string. Third, perceptually significant features, such as spaces, define potential words. Fourth, the whole, rather than part, of a letter is neglected. Fifth, category information is preserved. It is concluded that the Caramazza-Hillis model accounts well for RR's data, although we conclude that neglect dyslexia can be present when a more general visuospatial neglect is absent.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Eel culture is solely dependent on wild seed stock, caught in estuaries during the freshwater migratory phase as glass eels. The methods used for weaning glass eels are very variable, and range from the use of live zooplankton to fish roe to fines of commercial fish feeds. The present experiments were conducted on glass eels of the Australian shortfin eel, when the effectiveness of four types of readily available fish roe (European carp, mirror dory, orange roughy and warehou) were evaluated over a 42-day period, in the laboratory.

After 28 days the eels did not show an interest in orange roughy and mirror dory roe, and these two treatments were discontinued to avoid mortality. In all treatments there was a decrease in mean weight during this period, but the survival was over 99%. In the 28th to 42nd day period the mean weight and specific growth rate of glass eels reared on European carp and warehou roe increased, but the differences between these two treatments were not significant.

The physical features of the roe and the oocytes thereof, the proximate composition, amino acid and fatty acid composition indicated major differences amongst the roe types, particularly with regard to the amount of n−6 polyunsaturated fatty acids (PUFA) and the ratio of n−3 to n−6. European carp and warehou roe (and oocytes) had a significantly higher arachidonic acid (AA-20:4n−6; over 60% of PUFA) content and a considerably lower n−3 to n−6 ratio (n−3 to n−6 ratio being 1.32, 5.92, 3.77 and 2.67 for roe types, and 1.25, 4.83, 2.91 and 2.42 for oocytes, of European carp, mirror dory, orange roughy and warehou, respectively), than in the other two roe types. The fatty acid profiles of European carp and warehou roe were similar to that of metamorphosing glass eels.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

This article examines the application of different views of representation in the electoral systems at local government level: interest, corporate and mirror representation. The electoral framework underpins the process of representation, influencing both who are eligible to become voters and how their votes are collected and counted. The paper examines the  interrelationship between representation and the electoral framework in local government in Victoria. We use a historical analysis, and identify a long period of interest representation; a short, relatively recent period of corporate representation; and an attempt to introduce some elements of mirror representation. We conclude by arguing that local electoral reform needs to take into account the multiple meanings of representation.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Electronic contracts mirror the paper versions exchanged between businesses today, and offer the possibility of dynamic, automatic creation and enforcement of restrictions and compulsions on service behaviour that are designed to ensure business objectives are met. Where there are many contracts within a particular application, it can be difficult to determine whether the system can reliably fulfil them all, yet computer-parsable electronic contracts may allow such verification to be automated. In this chapter, we describe a conceptual framework and architecture specification in which normative business contracts can be electronically represented, verified, established, renewed, and so on. In particular, we aim to allow systems containing multiple contracts to be checked for conflicts and violations of business objectives. We illustrate the framework and architecture with an aerospace aftermarket example.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

It is rare for data's history to include computational processes alone. Even when software generates data, users ultimately decide to execute software procedures, choose their configuration and inputs, reconfigure, halt and restart processes, and so on. Understanding the provenance of data thus involves understanding the reasoning of users behind these decisions, but demanding that users explicitly document decisions could be intrusive if implemented naively, and impractical in some cases. In this paper, therefore, we explore an approach to transparently deriving the provenance of user decisions at query time. The user reasoning is simulated, and if the result of the simulation matches the documented decision, the simulation is taken to approximate the actual reasoning. The plausibility of this approach requires that the simulation mirror human decision -making, so we adopt an automated process explicitly modelled on human psychology. The provenance of the decision is modelled in OPM, allowing it to be queried as part of a larger provenance graph, and an OPM profile is provided to allow consistent querying of provenance across user decisions.