1000 resultados para rotational band


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The structural and electronic properties of perylene diimide liquid crystal PPEEB are studied using ab initio methods based on the density functional theory (I)FT). Using available experimental crystallographic data as a guide, we propose a detailed structural model for the packing of solid PPEEB. We find that due to the localized nature of the band edge wave function, theoretical approaches beyond the standard method, such as hybrid functional (PBE0), are required to correctly characterize the band structure of this material. Moreover, unlike previous assumptions, we observe the formation of hydrogen bonds between the side chains of different molecules, which leads to a dispersion of the energy levels. This result indicates that the side chains of the molecular crystal not only are responsible for its structural conformation but also can be used for tuning the electronic and optical properties of these materials.

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Denna uppsats handlar om förekomsten av Antisemitism i den svenska s.k. Vit makt-musiken. Uppsatsens syfte är att kartlägga förekomsten av antisemitism i tre vit makt- band: Pluton Svea, Storm och Dirlewanger. Analysen sker genom att texterna till två album av varje band studeras. Metoden är både kvalitativ som kvantitativ och bland annat så undersöks olika typer av antisemitiska uttalanden som därefter nivåsätts enligt en, av författaren, modifierad skala konstruerad av forskaren John C.G. Röhl. Resultatet av denna undersökning visar att antisemitism är ständigt närvarande i denna musikstil. Dock tar den sig olika uttryck beroende på vilket band det gäller. I de album som är producerade under 2000-talet tycks även en viss nedtoning av den våldsammaste formen av antisemitism kunna ses.

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I denna uppsats så ställs frågan om det går att effektivisera dagens PA-teknik. Detta på ett sätt som gynnar tekniker, musiker och mindre band. Undersökningen som genomfördes innefattade en litteraturundersökning och flertalet intervjuer med personer som på olika sätt arbetar med ljud och musik i livesammanhang.Resultaten visar att det går att effektivisera PA-tekniken mer än vad som görs idag. I och medden digitala teknikens introducerande så underlättas både teknikers och musikers jobb. Den traditionella multikabeln kan ersättas med varianter baserade på Ethernet. Olika varianter av teknik kan användas för att underlätta arbetet med monitorer, exempelvis In-ear monitoring. Uppsatsen presenterar olika knep för hur man kan förhindra feedback och genomföra en effektivare soundcheck. Slutligen diskuteras hur mindre band kan dra fördel av den digitala tekniken.

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The Sagnac effect is an important phase coherent effect in optical and atom interferometers where rotations of the interferometer with respect to an inertial reference frame result in a shift in the interference pattern proportional to the rotation rate. Here, we analyze the Sagnac effect in a mesoscopic semiconductor electron interferometer. We include in our analysis the Rashba spin-orbit interactions in the ring. Our results indicate that spin-orbit interactions increase the rotation-induced phase shift. We discuss the potential experimental observability of the Sagnac phase shift in such mesoscopic systems.

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Two experiments were conducted to clarify the roles of grain size, solute carbon and strain in determining the recrystallization textures of cold-rolled and annealed steels. In the first experiment, samples of coarse-grained low-carbon (LC) and interstitial-free (IF) steels were cold-rolled to a 75% reduction in thickness. One sample from each steel was polished and cold-rolled an additional 5%, while the remaining samples were annealed for various times at 650°C. In the second experiment, three samples from a commercial LC steel sheet were rolled 70% at 300°C. Two of the samples were given a further rolling reduction of 5% of the original thickness, with one of the samples being given this additional reduction at 300°C and the other at room temperature. Goss recrystallization textures are strengthened by coarse initial grain sizes, the presence of solute carbon and rolling at a temperature where dynamic strain ageing occurs, but are weakened by additional rolling beyond a reduction of 70%, especially when this extra rolling is conducted at a temperature where dynamic strain ageing does not occur. Characterization of key features of the deformed and recrystallized steels using optical microscopy, scanning electron microscopy (SEM) and electron back-scatter diffraction (EBSD) supports a rationale for these effects based on the repeated activation and deactivation of shear bands and the influence of solute carbon and dynamic strain ageing on the operating life of the bands and the accumulation of strain within them.

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The paper introduces four families of three-DOFs translational-rotational Parallel-Kinematics Mechanisms (PKMs) as well as the mobility analysis of such families using Lie group theory. Two of these families are mechanisms with one-rotational two-translational degrees of freedom (DOFs) and each of the other two has one-translational two-rotational DOFs. Four novel mechanisms are presented and discussed as representatives of these four families. Although these mechanisms are asymmetric, the components used to realise them are very similar and, hence, there is no great departure from the favourable modularity of parallel-kinematics mechanisms.


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The paper introduces a family of three-DOFs translational-rotational Parallel-Kinematics Mechanisms (PKMs) as well as the mobility analysis of such family using Lie-group theory. Each member of this family has two-rotational one-translational DOFs. A novel mechanism is presented and analyzed as a representative of that family. The use and the practical value of that modular mechanism are emphasized.


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The recent successful development of the equal channel angular pressing (ECAP) process in metals provides a feasible solution to produce ultra-fine or nano-grained bulk: materials with tailored material properties. However, ECAP is difficult to scale up commercially due to excessive load requirements. In this paper, a new Multi-ECAP process with die rotation is considered to obtain ultra-fine grain structured materials under a moderate deformation force. It is shown that an addition of torsion results in a reduction in the pressing force and an increase in severity of plastic deformation. An analysis using the upper bound method is found to be useful in predicting the pressing load and flow pattern of ECAP with and without rotational dies. Solutions are obtained for different inclined channel angles under different angular velocities of dies. Relative pressures are presented and some computed solutions are compared with those found by FEM simulation. The theoretical predictions of the pressing load are in good agreement with the simulation results. The amount of plastic deformation is determined by the inclined angle between the two intersecting channels, and the velocity ratio between the angular velocity of dies and the normal component of the punch velocity.

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The Osoyoos Indian Band case study signals the beginning of a PhD research project that will take approximately three years to complete. Taken in isolation, the objectives for the Osoyoos case study are modest. We want to refine our theoretical model and improve the case study protocol before embarking on a set of 5 case studies to explore Indigenous entrepreneurship; what it is, what communities do to succeed and a generalized definition of a successful venture from an Indigenous Canadian perspective.

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Zebra finches have previously been found to have preferences for particular colours of both natural and artificial traits among opposite sex conspecifics. For example, in some studies female zebra finches preferred males wearing red leg bands to orange-banded and unbanded birds and rejected light green-banded males. In other studies, females also preferred males with red beaks to orange-beaked males. However, several authors have failed to replicate these results. We show that females may fail to show a colour preference because of the absence or removal of ultraviolet light under experimental conditions. In mate-choice trials, females observing males through filters that transmitted ultraviolet preferred red-banded males but where females viewed males through ultraviolet-blocking filters, no such preference was observed. Further investigation revealed that the lack of a colour preference when ultraviolet was absent was probably due to the change in overall appearance of the bird, rather than the change in appearance of the rings themselves. This work highlights the importance of proper consideration of the sensory capabilities of animals in experimental design, particularly with regard to the role of ultraviolet light in avian colour perception. (C) 1997 The Association for the Study of Animal Behaviour.

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This dissertation reports on a study of music making in a band of the Australian Army Band Corps. The thesis of the dissertation is how the world views of the soldier-musicians of the Australian Army Band, Kapooka, are constructed in the context of their work in military music performance. In arguing this thesis, the author provides a brief history of military music in Australia, and - demonstrates how rank and military discipline intersect with music making in the lived experience of the soldier-musicians; - explores how the dichotomy between music making as a craft and music making as art is resolved in a setting where the employer regards music making as a trade, while the soldier-musicians strive to meet artistic goals; - demonstrates how successful music making and successful soldiering are both forms of work which depend upon effective collective action; - demonstrates that while military bands play the widest repertoire of musical styles of any Western music ensemble, the styles converge toward a homogenous, eclectic, military band performance style: and - explores how military music, which may have limited intrinsic interest, in certain ceremonial settings may link with other visual and auditory symbol systems to generate profound meaning both for the soldier-musicians themselves and for their audiences. The study examines the processes by which the world views of soldier-musicians are shaped by the institutional context in which they work, as they participate in a music tradition which has been a powerful agent in the shaping of Australian patriotic traditions. The study uses a naturalistic participant observation methodology. The author worked as an honorary guest civilian member of the band’s trombone section to collect data in the form of fieldnotes and interviews. Data analysis and interpretation was made according to the tenets of grounded theory. Evidence in the form of first hand accounts from the perspective of the researcher and from the soldier-musicians themselves is employed to generate both emic and etic understandings. An understanding of a music culture from the participant's point of view is a central concern of the study.

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This paper presents design of an electrostatic wide band shunt capacitive coupling RF MEMS switch with low actuation voltage. The key factors of the RF MEMS switch design are the proper scattering parameters, low actuation voltage, and the cost of the fabrication process. An overview of the recent low actuation voltage RFMEMS switches has been presented. These designs still suffer from the complexity of process, lack of reliability, limitation of frequency band, and process cost. RF characteristics of a shunt RF MEMS switches are specified mostly by coupling capacitor in upstate position of the membrane Cu. This capacitor is in trade-off with actuation voltage. In this work, the capacitor is eliminated by using two short high impedance transmission lines, at the input and output of the switch. The simulation results demonstrate an improvement in the RF characteristic of the switch.