999 resultados para D-eigenvalues


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An optical communication scheme of 2-D pattern transfer based on imaging optics for submarine laser uplink communication (SLUC) is suggested. Unlike the methods aiming at avoiding neighboring crosstalk used in traditional multi-channel optical beam transferring, we make full use of the overlapping of each spreading beam other than controlling divergence effect of each beam to avoid interference noise. The apparent parameters have been introduced to simplify theoretical analysis of optical pattern transfer problem involving underwater condition, with the help of which the complex beam propagation inside two kinds of mediums can be easily reduced to brief beam transfer only inside air medium. In this paper, optical transmission path and receiver terminal optics geometry have been described in detail. The link range equation and system uplink performance analysis have also been given. At last, results of a proof-of-concept experiment indicate good feasibility of the proposed SLUC model. © 2007 Elsevier GmbH. All rights reserved.

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The matrices studied here are positive stable (or briefly stable). These are matrices, real or complex, whose eigenvalues have positive real parts. A theorem of Lyapunov states that A is stable if and only if there exists H ˃ 0 such that AH + HA* = I. Let A be a stable matrix. Three aspects of the Lyapunov transformation LA :H → AH + HA* are discussed.

1. Let C1 (A) = {AH + HA* :H ≥ 0} and C2 (A) = {H: AH+HA* ≥ 0}. The problems of determining the cones C1(A) and C2(A) are still unsolved. Using solvability theory for linear equations over cones it is proved that C1(A) is the polar of C2(A*), and it is also shown that C1 (A) = C1(A-1). The inertia assumed by matrices in C1(A) is characterized.

2. The index of dissipation of A was defined to be the maximum number of equal eigenvalues of H, where H runs through all matrices in the interior of C2(A). Upper and lower bounds, as well as some properties of this index, are given.

3. We consider the minimal eigenvalue of the Lyapunov transform AH+HA*, where H varies over the set of all positive semi-definite matrices whose largest eigenvalue is less than or equal to one. Denote it by ψ(A). It is proved that if A is Hermitian and has eigenvalues μ1 ≥ μ2…≥ μn ˃ 0, then ψ(A) = -(μ1n)2/(4(μ1 + μn)). The value of ψ(A) is also determined in case A is a normal, stable matrix. Then ψ(A) can be expressed in terms of at most three of the eigenvalues of A. If A is an arbitrary stable matrix, then upper and lower bounds for ψ(A) are obtained.

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IDOKI SCF Technologies S.L. is a technology-based company, set up on September 2006 in Derio (Biscay) with the main scope of developing extraction and purification processes based on the use of supercritical fluid extraction technology (SFE) in food processing, extraction of natural products and the production of personal care products. IDOKI¿s researchers have been working on many different R&D projects so far, most of them using this technology. However, the optimization of a SFE method for the different matrices cannot be performed unless we have an analytical method for the characterisation of the extracts obtained in each experiment. The analytical methods are also essential for the quality control of the raw materials that are going to be used and also for the final product. This PhD thesis was born to tackle this problem and therefore, it is based on the development of different analytical methods for the characterisation of the extracts and products. The projects that we could include in this thesis were the following: the extraction propolis, the recovery of agroindustrial residues (soy and wine) and the dealcoholisation of wine.On the one hand, for the extraction of propolis, several UV-Vis spectroscopic methods were used in order to measure the antioxidant capacity and the total polyphenol and flavonoid content of the extracts. A SFC method was also developed in order to measure more specific phenolic compounds. On the other hand, for the recovery of agroindustrial residues UV-Vis spectroscopy was used to determine the total polyphenol content and two SFC methods were developed to analyse different phenolic compounds. Extraction methods such as MAE, FUSE and rotary agitation were also evaluated for the characterisation of the raw materials.Finally, for the dealcoholisation of wine, the development of a SBSE-TD-GC-MS and DHS-TD-GC-MS methods for the analysis of aromas and a NIR spectroscopic method for the determination of ethanol content with the help of chemometrics was necessary. Most of these methods are typically used in IDOKI¿s lab as routine analyses apart from others not included in this PhD thesis.

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Duración (en horas): De 21 a 30 horas Destinatario: Estudiante y Docente

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Jakina da informatika oso gai zabala dela. Horregatik, oro har, sistema informatikoen garatzaileak sistemaren osagai bakan batzuetaz soilik arduratzen dira. Proiektu honek hardwarearen eta softwarearen munduak uztartzea du helburu; hardware- eta softwareosagaiak dituen sistema bat sortu, behar diren osagai guztiak garatuz. Horretaz gain, garatutakoa erabilgarria izatea bilatu da, hau da, funtzio praktiko eta erreal bat edukitzea. Horretarako, Android eta Arduino plataformak aztertu dira: Android erabiltzaileari interfaze grafikoa eskaini eta elkarrekintza burutzeko erabili da; Arduino, berriz, hardwarearen kontrolatzailea izateko. Horrekin, eragingailuak kontrolatuz, time-lapseak egiteko sistema automatizatua garatu da; D-Lappse Android aplikazioarekin sistema kontrolatu daiteke eta dollyari aginduak bidali, argazki-sekuentziak era automatizatu batean egiteko.

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利用5m长的D型双包层掺Yb^3+光纤,采用声光调制锁模信号系统,实验上成功研制出输出320MHz的高重复频率脉冲列的光纤放大器,得到了20dB的增益输出,输出激光波长1064nm,输出平均功率1.02W,该光纤放大器可作为空间激光通信系统发射源。整个实验系统装置由作为信号源的特高重频脉冲列激光器、作为放大环节的光纤放大器和绿光倍频三个部分组成,另外对光纤放大器自激振荡谱线的各影响因素做了一些相关的实验研究,并对结果进行了分析讨论,提出了改进措施。

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Apresentamos um estudo preliminar da produção difrativa de mésons utilizando dados obtidos da colisão próton-próton, a energias de centro de massa de 7 TeV, com o experimento CMS-LHC. O trabalho inclui o desenvolvimento do algoritmo de reconstrução dos mésons D* através do canal de decaimento D*->D0 + pion (lento) ->K+pion, a medida da eficiência de detecção e reconstrução, e uma análise do comportamento de variáveis cinemáticas na produção difrativa dessas partículas, particularmente, das lacunas de rapidez. Para isso, foi utilizada uma luminosidade integrada de 3,171pb^(-1) de dados coletados no ano de 2010. As análises com os dados experimentais foram comparadas com os resultados obtidos com geradores de Monte Carlo PYTHIA6, PYTHIA8 e POMPYT.

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Tellurite glass is proposed as a host for broadband erbium-doped fiber amplifiers because of their excellent optical and chemical properties. A single-mode Er3+-doped tellurite glass fiber with D-shape cladding was fabricated in this work. The characterization of amplified spontaneous emission (ASE) from this newly fabricated Er3+-doped tellurite fibers are exhibited. When pumped at 980 nm, a very broad erbium ASE nearly 150 nm around 1.53 mum is observed. The changes in ASE with regard to fiber lengths and pumping power were measured and discussed. The output of 2 mW from Er3+-doped tellurite fiber ASE source was obtained under the pump power of 660 mW. The broad 1.53 mum emission of Er3+ in tellurite glass fiber can be used as host material for potential broadband optical amplifier and tunable fiber lasers. (C) 2004 Elsevier B.V. All rights reserved.