33 resultados para PRISM COUPLER
em Queensland University of Technology - ePrints Archive
Resumo:
Here, we demonstrate that efficient nano-optical couplers can be developed using closely spaced gap plasmon waveguides in the form of two parallel nano-sized rectangular slots in a thin metal film or membrane. Using the rigorous numerical finite-difference and finite element algorithms, we investigate the physical mechanisms of coupling between two neighboring gap plasmon waveguides and determine typical coupling lengths for different structural parameters of the coupler. Special attention is focused onto the analysis of the effect of such major coupler parameters, such as thickness of the metal film/membrane, slot width, and separation between the plasmonic waveguides. Detailed physical interpretation of the obtained unusual dependencies of the coupling length on slot width and film thickness is presented based upon the energy consideration. The obtained results will be important for the optimization and experimental development of plasmonic sub-wavelength compact directional couplers and other nano-optical devices for integrated nanophotonics.
Resumo:
The insolvency of natural persons raises questions not only for a nation’s economy but also for its concern for equity. The World Bank has recently released a Report on the Treatment of the Insolvency of Natural Persons to guide nations in addressing the issues raised by an individual debtor’s insolvency. A brief review of Australia’s personal insolvency laws shows that it addresses many of the issues raised by the Report. However two areas are identified as worthy of further investigation by policy-makers and scholars to better address a concern for equity.
Resumo:
This work investigates the feasibly in using a low noise “C” Band block down-converter as a Ultra High Frequency window coupler for the detection of partial discharge activity from free conducting practices and a protrusion on the high voltage conductor in Gas Insulated Switchgear. The investigated window coupler has a better sensitivity than the internal Ultra High Frequency couplers fitted to the system. The investigated window couplers however are sensitive to changes in the frequency content of the discharge signals and appear to be less sensitive to negative discharges signals produced by a protrusion than the positive discharge signals.
Resumo:
This article examines the relevance of James Grunig and Todd Hunt’s (1984) theories to public relations practitioners’ roles in south east Queensland schools. It focuses in particular on the two-way symmetric model in this context. The geographical boundaries of the research mean that this article is intended primarily as an exploratory, descriptive analysis of a specific area rather than an exhaustive treatise on the general topic of public relations in Australian schools. However, it is hoped that it will prove useful in identifying bases for further study and discussion.
Resumo:
This research investigated underlying issues that were critical to the success of the bifocal trial and comprised of three studies. The first study evaluated if Chinese-Canadian children were suitable subjects for the bifocal trial. The high prevalence of myopia in Chinese children suggests that genetic input plays a role in myopia development, but the rapid increase in prevalence over the last few decades indicates environmental factors are also important. Since this bifocal trial was conducted in Canada, this work aimed to determine whether Chinese children who had migrated to Canada would still have high myopia prevalence and a high rate of myopia progression. The second study determined the optimal bifocal lens power for myopia treatment and the effect of incorporating base-in prism into the bifocal. In the majority of published myopia control studies, the power of the prescribed near addition was usually predetermined in the belief that the near addition would always help to improve the near focus. In fact, the effect of near addition on the accommodative error might be quite different even for individuals in which the same magnitude of accommodation lag had been measured. Therefore, this work was necessary to guide the selection of bifocal and prism powers most suitable for the subsequent bifocal trial. The third study, the ultimate goal of this research, was to conduct a longitudinal clinical trial to determine if bifocals and prismatic bifocals could control myopia progression in children.
Resumo:
The aim of this exploratory study was to gain an insight into Asian and Western public relations practices by investigating them through job advertisements and thus reflecting on what organisations expect from the public relations professionals. Grunig's (1984) four models of public relations and the concept of relationships management were used as the foundation for this study. Australia was used to represent the Western region and India was used to represent the Asian region. Sample sets of public relations recruitment advertisements from both countries were examined against Grunig's one-way communication, two-way communication and relationship management attributes.
Resumo:
Objective: To determine whether bifocal and prismatic bifocal spectacles could control myopia in children with high rates of myopic progression. ---------- Methods: This was a randomized controlled clinical trial. One hundred thirty-five (73 girls and 62 boys) myopic Chinese Canadian children (myopia of 1.00 diopters [D]) with myopic progression of at least 0.50 D in the preceding year were randomly assigned to 1 of 3 treatments: (1) single-vision lenses (n = 41), (2) +1.50-D executive bifocals (n = 48), or (3) +1.50-D executive bifocals with a 3–prism diopters base-in prism in the near segment of each lens (n = 46). ---------- Main Outcome Measures: Myopic progression measured by an automated refractor under cycloplegia and increase in axial length (secondary) measured by ultrasonography at 6-month intervals for 24 months. Only the data of the right eye were used. ---------- Results: Of the 135 children (mean age, 10.29 years [SE, 0.15 years]; mean visual acuity, –3.08 D [SE, 0.10 D]), 131 (97%) completed the trial after 24 months. Myopic progression averaged –1.55 D (SE, 0.12 D) for those who wore single-vision lenses, –0.96 D (SE, 0.09 D) for those who wore bifocals, and –0.70 D (SE, 0.10 D) for those who wore prismatic bifocals. Axial length increased an average of 0.62 mm (SE, 0.04 mm), 0.41 mm (SE, 0.04 mm), and 0.41 mm (SE, 0.05 mm), respectively. The treatment effect of bifocals (0.59 D) and prismatic bifocals (0.85 D) was significant (P < .001) and both bifocal groups had less axial elongation (0.21 mm) than the single-vision lens group (P < .001). ---------- Conclusions: Bifocal lenses can moderately slow myopic progression in children with high rates of progression after 24 months.
Resumo:
Purpose: To investigate the influence of convergence on axial length and corneal topography in young adult subjects.---------- Methods: Fifteen emmetropic young adult subjects with normal binocular vision had axial length and corneal topography measured immediately before and after a 15-min period of base out (BO) prismatic spectacle lens wear. Two different magnitude prismatic spectacles were worn in turn (8 [DELTA] BO and 16 [DELTA] BO), and for both tasks, distance fixation was maintained for the duration of lens wear. Eight subjects returned on a separate day for further testing and had axial length measured before, during, and immediately after a 15-min convergence task.---------- Results: No significant change was found to occur in axial length either during or after the sustained convergence tasks (p > 0.6). Some small but significant changes in corneal topography were found to occur after sustained convergence. The most significant corneal change was observed after the 16 [DELTA] BO prism wear. The corneal refractive power spherocylinder power vector J0 was found to change by a small (mean change of 0.03 D after the 16 [DELTA] BO task) but statistically significant (p = 0.03) amount as a result of the convergence task (indicative of a reduction in with-the-rule corneal astigmatism after convergence). Corneal axial power was found to exhibit a significant flattening in superior regions. Conclusions: Axial length appears largely unchanged by a period of sustained convergence. However, small but significant changes occur in the topography of the cornea after convergence.
Resumo:
Entertainment is consumer-driven culture, and some consumers of entertainment products display uncommon levels of loyalty towards their favourite sports star, actor or musician. This essay examines fanaticism and loyalty through the prism of consumer rituals. Further, a Ritual-Loyalty model is proposed to help investigate the relationship between the constructs. Finally, the paper offers directions for future research regarding entertainment consumers.
Resumo:
We both love and hate our journalists. They are perceived as sexy and glamorous on the one hand, despicable and sleazy on the other. Opinion polls regularly indicate that we experience a kind of cultural schizophrenia in our relationship to journalists and the news media: sometimes they are viewed as heroes, at other times villains. From Watergate to the fabrication scandals of the 2000s, journalists have risen and fallen in public esteem. In this book, leading journalism studies scholar Brian McNair explores how journalists have been represented through the prism of one of our key cultural forms, cinema. Drawing on the history of cinema since the 1930s, and with a focus on the period 1997-2008, McNair explores how journalists have been portrayed in film, and what these images tell us about the role of the journalist in liberal democratic societies. Separate chapters are devoted to the subject of female journalists in film, foreign correspondents, investigative reporters and other categories of news maker who have featured regularly in cinema. The book also discusses the representation of public relations professionals in film. Illustrated throughout and written in an accessible and lively style suitable for academic and lay readers alike, Journalists in Film will be essential reading for students and teachers of journalism, and for all those concerned about the role of the journalist in contemporary society, not least journalists themselves. An appendix contains mini-essays on every film about journalism released in the cinema between 1997 and 2008.
Resumo:
The size of rat-race and branch-line couplers can be reduced by using periodic loading or artificial transmission lines. The objective of this work is to extend the idea of size reduction through periodic loading to coupled-line 90° hybrids. A procedure for the extraction of the characteristic parameters of a coupled-line 4-port from a single set of S-parameters is described. This method can be employed to design of coupled artificial transmission line couplers of arbitrary geometry. The procedure is illustrated through the design a broadside-coupled stripline hybrid, periodically loaded with stubs. Measured results for a prototype coupler confirm the validity of the theory.
Resumo:
In this paper, we investigate theoretically and numerically the efficiency of energy coupling from a plasmon generated by a grating coupler at one of the interfaces of a metal wedge into the plasmonic eigenmode (i.e., symmetric or quasisymmetric plasmon) experiencing nanofocusing in the wedge. Thus the energy efficiency of energy coupling into metallic nanofocusing structure is analyzed. Two different nanofocusing structures with the metal wedge surrounded by a uniform dielectric (symmetric structure) and with the metal wedge enclosed between a substrate and a cladding with different dielectricpermittivities (asymmetric structure) are considered by means of the geometrical optics (adiabatic) approximation. It is demonstrated that the efficiency of the energy coupling from the plasmon generated by the grating into the symmetric or quasisymmetric plasmon experiencing nanofocusing may vary between ∼50% to ∼100%. In particular, even a very small difference (of ∼1%–2%) between the permittivities of the substrate and the cladding may result in a significant increase in the efficiency of the energy coupling (from ∼50% up to ∼100%) into the plasmon experiencing nanofocusing. Distinct beat patterns produced by the interference of the symmetric (quasisymmetric) and antisymmetric (quasiantisymmetric) plasmons are predicted and analyzed with significant oscillations of the magnetic and electric field amplitudes at both the metal wedge interfaces. Physical interpretations of the predicted effects are based upon the behavior, dispersion, and dissipation of the symmetric (quasisymmetric) and antisymmetric (quasiantisymmetric) filmplasmons in the nanofocusing metal wedge. The obtained results will be important for optimizing metallic nanofocusing structures and minimizing coupling and dissipative losses.
Resumo:
An often overlooked aspect concerning the Glashaus is the significant influence exerted by the client in the design of the building. In an intentional endeavour to create an exhibition pavilion that best showcased their glazed products and construction technologies, the German Luxfer Prism Syndicate both commissioned and majority financed the Glashaus. It would therefore seem strange that the official histories of the Glashaus would rather record the utopian, romanticised and arguably imagined intentions of Bruno Taut as the architect, as opposed to the reality of the client’s intentions. This paper offers a reinterpretation of the Glashaus from the perspective of German Luxfer Prism Syndicate. This reinterpretation is achieved through an investigation that primarily concentrates on the glazed areas of the Glashaus where the German Luxfer Prism Syndicates products were most evident. Using the arguments initially presented by Dietrich Neumann as a foundation, this research is additionally interwoven with inquiry into diverse aspects such as patents filed by the Luxfer group of companies and a close examination of the original black and white photographs of the Glashaus. A dramatically different understanding emerges when the Glashaus is argued from the perspective of the client; an understanding that is cold, hard and commercial as opposed to utopian and romanticised. As a result, this research makes a contribution to the current debate concerning the Glashaus and the re-evaluation of the histories of the modern movement.
Resumo:
Purpose. The purpose of the study was to investigate the changes in axial length occurring with shifts in gaze direction. Methods. Axial length measurements were obtained from the left eye of 30 young adults (10 emmetropes, 10 low myopes, and 10 moderate myopes) through a rotating prism with 15° deviation, along the foveal axis, using a noncontact optical biometer in each of the nine different cardinal directions of gaze over 5 minutes. The subject's fellow eye fixated on an external distance (6 m) target to control accommodation, also with 15° deviation. Axial length measurements were also performed in 15° and 25° downward gaze with the biometer inclined on a tilting table, allowing gaze shifts to be achieved with either full head turn but no eye turn, or full eye turn with no head turn. Results. There was a significant influence of gaze angle and time on axial length (both P < 0.001), with the greatest axial elongation (+18 ± 8 μm) occurring with inferonasal gaze (P < 0.001) and a slight decrease in axial length in superior gaze (−12 ± 17 μm) compared with primary gaze (P < 0.001). In downward gaze, a significant axial elongation occurred when eye turn was used (P < 0.001), but not when head turn was used to shift gaze (P > 0.05). Conclusions. The angle of gaze has a small but significant short-term effect on axial length, with greatest elongation occurring in inferonasal gaze. The elongation of the eye appears to be due to the influence of the extraocular muscles, in particular the oblique muscles.
Resumo:
Objective: Substance use is common in first-episode psychosis, and complicates the accurate diagnosis and treatment of the disorder. The differentiation of substance-induced psychotic disorders (SIPD) from primary psychotic disorders (PPD) is particularly challenging. This cross-sectional study compares the clinical, substance use and functional characteristics of substance using first episode psychosis patients diagnosed with a SIPD and PPD. Method: Participants were 61 young people (15-24 years) admitted to a psychiatric inpatient service with first episode psychosis, reporting substance use in the past month. Diagnosis was determined using the Psychiatric Research Interview for DSM-IV Substance and Mental disorders (PRISM-IV). Measures of clinical (severity of psychotic symptoms, level of insight, history of trauma), substance use (frequency/quantity, severity) and social and occupational functioning were also administered. Results: The PRISM-IV differentially diagnosed 56% of first episode patients with a SIPD and 44% with a PPD. Those with a SIPD had higher rates of substance use and disorders, higher levels of insight, were more likely to have a forensic and trauma history and had more severe hostility and anxious symptoms than those with a PPD. Logistic regression analysis indicated a family history of psychosis, trauma history and current cannabis dependence were the strongest predictors of a SIPD. Almost 80% of diagnostic predictions of a SIPD were accurate using this model. Conclusions: This clinical profile of SIPD could help to facilitate the accurate diagnosis and treatment of SIPD versus PPD in young people with first episode psychosis admitted to an inpatient psychiatric service.