USE OF RETRODIRECTIVE ARRAY PHASE CONJUGATION CIRCUITRY FOR NEAR- AND FAR-FIELD POSITION ANGLE OF ARRIVAL DETECTION

In this article, we present position indication functionality as obtained by using a retrodirective array, thereby allowing location information extraction of the position of the remote transmitter with which the retrodirective array is cooperating. This is carried out using straightforward circuitry with no requirement for complex angle of arrival algorithms, thereby giving a result in real time enabling tracking of fast moving transmitters. We show using a 10 x element retrodirective array, operating at 2.4 GHz that accuracies of far-field angle of arrival of within +/- 1 degrees over the arrays +/- 30 degrees azimuth field of view are possible. While in the near-field for angles of arrival of +/- 10 degrees it is possible to extract the position of a dipole source down to a resolution of 032 lambda. (C) 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1031-1034, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25097

Probing the decay characteristics of the Pygmy Dipole Resonance in the semi-magic nucleus 140 Ce with gamma-gamma coincidence measurements

Im Rahmen dieser Arbeit wurde ein neuartiger Experimentaufbau -- das γ3 Experiment -- zur Messung von photoneninduzierten Kern-Dipolanregungen in stabilen Isotopen konzipiert und an der High Intensity γ-Ray Source (HIγS) an der Duke University installiert.rnDie hohe Energieauflösung und die hohe Nachweiseffizienz des Detektoraufbaus, welcher aus einer Kombination von LaBr Szintillatoren und hochreinen Germanium-Detektoren besteht, erlaubt erstmals die effiziente Messung von γ-γ-Koinzidenzen in Verbindung mit der Methode der Kernresonanzfluoreszenz.rnDiese Methode eröffnet den Zugang zum Zerfallsverhalten der angeregten Dipolzustände als zusätzlicher Observablen, die ein detaillierteres Verständnis der zugrunde liegenden Struktur dieser Anregungen ermöglicht.rnDer Detektoraufbau wurde bereits erfolgreich im Rahmen von zwei Experimentkampagnen in 2012 und 2013 für die Untersuchung von 13 verschiedenen Isotopen verwendet. Im Fokus dieser Arbeit stand die Analyse der Pygmy-Dipolresonanz (PDR) im Kern 140Ce im Energiebereich von 5,2 MeV bis 8,3 MeV basierend auf den mit dem γ3 Experimentaufbau gemessenen Daten. Insbesondere das Zerfallsverhalten der Zustände, die an der PDR beteiligt sind, wurde untersucht. Der Experimentaufbau, die Details der Analyse sowie die Resultate werden in der vorliegenden Arbeit präsentiert. Desweiteren erlaubt ein Vergleich der Ergebnisse mit theoretischen Rechnungen im quasi-particle phonon model (QPM) eine Interpretation des beobachteten Zerfallsverhaltens.

New modal feed network for a compact monopole array with isolated ports

An element spacing of less than half a wavelength introduces strong mutual coupling between the ports of compact antenna arrays. The strong coupling causes significant system performance degradation. A decoupling network may compensate for the mutual coupling. Alternatively, port decoupling can be achieved using a modal feed network. In response to an input signal at one of the input ports, this feed network excites the antenna elements in accordance with one of the eigenvectors of the array scattering parameter matrix. In this paper, a novel 4-element monopole array is described. The feed network of the array is implemented as a planar ring-type circuit in stripline with four coupled line sections. The new configuration offers a significant reduction in size, resulting in a very compact array.

Microphone array shape calibration in diffuse noise fields

This correspondence presents a microphone array shape calibration procedure for diffuse noise environments. The procedure estimates intermicrophone distances by fitting the measured noise coherence with its theoretical model and then estimates the array geometry using classical multidimensional scaling. The technique is validated on noise recordings from two office environments.

Air vehicle simulator : An application for a cable array robot

The development of autonomous air vehicles can be an expensive research pursuit. To alleviate some of the financial burden of this process, we have constructed a system consisting of four winches each attached to a central pod (the simulated air vehicle) via cables - a cable-array robot. The system is capable of precisely controlling the three dimensional position of the pod allowing effective testing of sensing and control strategies before experimentation on a free-flying vehicle. In this paper, we present a brief overview of the system and provide a practical control strategy for such a system. ©2005 IEEE.

A cable-array robot for air vehicle simulation

The development of autonomous air vehicles can be an expensive research pursuit. To alleviate some of the financial burden of this process, we have constructed a system consisting of four winches each attached to a central pod (the simulated air vehicle) via cables - a cable-array robot. The system is capable of precisely controlling the three dimensional position of the pod allowing effective testing of sensing and control strategies before experimentation on a free-flying vehicle. In this paper, we present a brief overview of the system and provide a practical control strategy for such a system.

Candidate metastasis suppressor genes uncovered by array comparative genomic hybridization in a mouse allograft model of prostate cancer.

Background The purpose of this study was to identify candidate metastasis suppressor genes from a mouse allograft model of prostate cancer (NE-10). This allograft model originally developed metastases by twelve weeks after implantation in male athymic nude mice, but lost the ability to metastasize after a number of in vivo passages. We performed high resolution array comparative genomic hybridization on the metastasizing and non-metastasizing allografts to identify chromosome imbalances that differed between the two groups of tumors. Results This analysis uncovered a deletion on chromosome 2 that differed between the metastasizing and non-metastasizing tumors. Bioinformatics filters were employed to mine this region of the genome for candidate metastasis suppressor genes. Of the 146 known genes that reside within the region of interest on mouse chromosome 2, four candidate metastasis suppressor genes (Slc27a2, Mall, Snrpb, and Rassf2) were identified. Quantitative expression analysis confirmed decreased expression of these genes in the metastasizing compared to non-metastasizing tumors. Conclusion This study presents combined genomics and bioinformatics approaches for identifying potential metastasis suppressor genes. The genes identified here are candidates for further studies to determine their functional role in inhibiting metastases in the NE-10 allograft model and human prostate cancer.