Parallel plate interferometer with a reflecting mirror for measuring angular displacement

A parallel plate interferometer with a reflecting mirror for measuring angular displacement is proposed. A deflection angle of a beam caused by an angular displacement is amplified by use of a reflecting mirror to increase the optical path difference (OPD) in the plane-parallel plate, which provides high sensitivity of the phase measurement. Detection of light transmitted through the plane-parallel plate with a position sensitive detector (PSD) enables high accurate measurement of the initial angle of incidence to the plane-parallel plate with insensitivity to stray light. The improved parallel plate interferometer achieves a measurement repeatability of 10(-8) rad. (C) 2007 The Optical Society of Japan.

Accuracy analysis of parallel plate interferometer for angular displacement measurement

The measurement accuracy of a parallel-plate interferometer for angular displacement measurement is analyzed. The measurement accuracy of angular displacement is not only related to the accuracy of phase extraction, but also related to initial incident angle, refraction index and thickness of plane-parallel plate as well as wavelength's stability of laser diode, etc. Theoretical analysis and computer simulation show that the measurement error of the angular displacement bears a minimum value when choosing an optimal initial incident angle in a large range. These analytical results serve as a guide in practical measurement. In this interferometer, reducing the refraction index or increasing the thickness of the parallel plate can improve the measurement accuracy; and the relative error of the phase measurement is 3.0 x 10(-4) corresponding to 1 degrees C temperature variation. Based on these theoretical and experimental results, the measurement accuracy of the parallel-plate interferometer is up to an order of 10(-8) rad. (c) 2007 Elsevier Ltd. All rights reserved.

One-shot parallel complex Fourier-domain optical coherence tomography using a spatial carrier frequency

We propose a novel method of one-shot parallel complex Fourier-domain optical coherence tomography using a spatial carrier frequency for full range imaging. The spatial carrier frequency is introduced into the 2-D spectral interferogram in the lateral direction by using a tilted reference wavefront. This spatial-carrier- contained 2-D spectral interferogram is recorded with one shot of a 2-D CCD camera, and is Fourier-transformed in the lateral direction to obtain a 2-D complex spectral interferogram by a spatial-carrier technique. A full-range tomogram is reconstructed from the 2-D complex spectral interferogram. The principle of this method is confirmed by cross-sectional imaging of a glass slip object. (c) 2008 Society of Photo-Optical Instrumentation Engineers.

Some engineering issues of an FBG sensor with the dual gratings parallel matched interrogation method

The key issues of engineering application of the dual gratings parallel matched interrogation method are expanding the measurable range, improving the usability, and lowering the cost by adopting a compact and simple setup based on existing conditions and improving the precision of the data-processing scheme. A credible and effective data-processing scheme based on a novel divisional look-up table is proposed based on the advantages of other schemes. Any undetermined data is belonged to a certain section, which can be confirmed at first, then it can be looked up in the table to correspond to microstrain by the scheme. It not only solves inherent problems of the traditional one (double value and small measurable range) but also enhances the precision, which improves the performance of the system. From the experimental results, the measurable range of the system is 525 mu epsilon, and the precision is +/- 1 mu epsilon based on normal matched gratings. The system works in real time, which is competent for most engineering measurement requirements. (C) 2007 Elsevier GmbH. All rights reserved.

On statistical treatment of the results of parallel trails with special reference to fishery research

Parallel trials form a most important part of the technique of scientific experimentation. Such trials may be divided into two; categories. In the first the results are comparable measurements of one kind or another. In the second the data consist of records of the number of times a certain 'event' has occurred in the two sets of trials compared. Only trials of the second category are dealt with here. In this paper all the reliable methods of testing for significance the results of parallel trials of a certain type with special reference to fishery research are described fully. Some sections relate to exact, others to approximate tests. The only advantage in the use of the latter lies in the fact that they are often the more expeditious. Apart from this it is always preferable to use exact methods.

As metáforas conceptuais da palavra paz nos relatórios do Conselho de Segurança das Nações Unidas: uma análise baseada em corpus digital

A presente pesquisa tem por objetivo investigar como a palavra paz é entendida, em termos de conceito, pelo Conselho de Segurança da Organização das Nações Unidas. Para tanto, são analisados trinta e sete relatórios oficiais produzidos pelo Conselho de Segurança, no período de agosto de 1994 a junho de 2009, acerca das missões de paz realizadas em trinta e uma regiões/países que apresentavam ameaça à paz e à segurança internacionais durante aquele período. De acordo com a Conselheira Gilda Santos Neves, chefe da Divisão das Nações Unidas do Ministério das Relações Exteriores, em seu texto O Brasil e a Criação da Comissão para a Consolidação da Paz (2008), a paz é algo que se consolida e não se constrói. Tal posição norteia a presente pesquisa, uma vez que o objetivo aqui é mapear as expressões linguísticas realizadas através da palavra paz. As bases teóricas desta pesquisa encontram-se fundamentadas na teoria da metáfora cognitiva, de Lakoff e Johnson (1980), bem como no estudo de Deignan (2005) em seu livro intitulado Metaphor and Corpus Linguistics, que visa a fornecer os benefícios que a abordagem cognitiva de metáforas pode obter através da análise de corpora digitalizados. Após compilar os relatórios do Conselho de Segurança e prepará-los para serem lidos pelo programa computacional WordSmith Tools 3.0, foram extraídas todas as ocorrências da palavra paz dos referidos relatórios. Das 686 ocorrências geradas, foram deixadas para análise somente aquelas com sentido metafórico e, no total, nove esquemas conceptuais foram construídos. A pesquisa feita sugere que, para o Conselho de Segurança, a paz é algo profundamente desejado tanto pela população das zonas de conflito quanto pela comunidade internacional. No entanto, a paz não é facilmente construída ou estabelecida. Alcançar a paz implica seguir um processo com diferentes etapas, ou seja, com início, meio e fim, bem como superar obstáculos e retrocessos que surgem no meio do caminho. Para tanto, diversos investimentos têm de ser feitos por todos aqueles envolvidos e realmente interessados na paz mundial. Por fim, vê-se que a visão da Conselheira Gilda Santos Neves, de acordo com as metáforas aqui analisadas, está correta, já que, conforme apontam os resultados do presente estudo, o conceito de paz, para o Conselho de Segurança, não é o de algo a ser construído do zero

Optimisation of the first principle code Octopus for massive parallel architectures: application to light harvesting complexes

150 p.