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Sample records for photons zweischleifenkorrekturen zur

  1. Photonics

    CERN Document Server

    Andrews, David L

    2015-01-01

    Discusses the basic physical principles underlying Biomedical Photonics, spectroscopy and microscopy This volume discusses biomedical photonics, spectroscopy and microscopy, the basic physical principles underlying the technology and its applications. The topics discussed in this volume are: Biophotonics; Fluorescence and Phosphorescence; Medical Photonics; Microscopy; Nonlinear Optics; Ophthalmic Technology; Optical Tomography; Optofluidics; Photodynamic Therapy; Image Processing; Imaging Systems; Sensors; Single Molecule Detection; Futurology in Photonics. Comprehensive and accessible cov

  2. Photonics

    CERN Document Server

    Andrews, David L

    2015-01-01

    Discusses the basic physical principles underlying the technology instrumentation of photonics This volume discusses photonics technology and instrumentation. The topics discussed in this volume are: Communication Networks; Data Buffers; Defense and Security Applications; Detectors; Fiber Optics and Amplifiers; Green Photonics; Instrumentation and Metrology; Interferometers; Light-Harvesting Materials; Logic Devices; Optical Communications; Remote Sensing; Solar Energy; Solid-State Lighting; Wavelength Conversion Comprehensive and accessible coverage of the whole of modern photonics Emphas

  3. Photonics

    CERN Document Server

    Andrews, David L

    2015-01-01

    Discusses the basic physical principles underlying thescience and technology of nanophotonics, its materials andstructures This volume presents nanophotonic structures and Materials.Nanophotonics is photonic science and technology that utilizeslight/matter interactions on the nanoscale where researchers arediscovering new phenomena and developing techniques that go wellbeyond what is possible with conventional photonics andelectronics.The topics discussed in this volume are: CavityPhotonics; Cold Atoms and Bose-Einstein Condensates; Displays;E-paper; Graphene; Integrated Photonics; Liquid Cry

  4. Photonics

    CERN Document Server

    Andrews, David L

    2015-01-01

    This book covers modern photonics accessibly and discusses the basic physical principles underlying all the applications and technology of photonicsThis volume covers the basic physical principles underlying the technology and all applications of photonics from statistical optics to quantum optics. The topics discussed in this volume are: Photons in perspective; Coherence and Statistical Optics; Complex Light and Singular Optics; Electrodynamics of Dielectric Media; Fast and slow Light; Holography; Multiphoton Processes; Optical Angular Momentum; Optical Forces, Trapping and Manipulation; Pol

  5. Two-photon contributions to the elastic electron-nucleon scattering in the Skyrme model; Zwei-Photon-Beitraege zur elastischen Elektron-Nukleon-Streuung im Skyrme-Modell

    Energy Technology Data Exchange (ETDEWEB)

    Kuhn, Markus

    2008-09-23

    The electromagnetic form factors are crucial for our understanding of the inner structure of the proton. Recently it has become feasible to measure them by the use of polarisation transfer techniques in addition to the traditional Rosenbluth separation method. Thereby emerged an incompatibility of the results obtained by these two different experimental methods. It is commonly assumed that the discrepance is induced by higher order corrections to the cross section, especially through two-photon exchange processes. Unfortunately these processes cannot be calculated in a model independent manner because off-shell photon nucleon vertices arise. Effective chiral lagrangians contain already local two-photon couplings and therefore seem exceptionally well suited to study the anomaly contribution to the two-photon exchange. These couplings give two-photon exchange contributions that can be understood as the coupling of the nucleon to pions, decaying into two virtual photons. A particular contribution emerges from the chiral anomaly of QCD, that describes the two-photon decay of the neutral pion. The most important goal of this work is the calculation of the contribution arising from the anomaly to the elastic electron-proton scattering. The results are expected to be widely model independent since the anomaly directly reflects a QCD property. Based on the Skyrme model the protons are realized as soliton solutions in effective chiral theories. The next to leading order contribution to the cross section is given by the interference between the one- and two-photon exchange. The latter contains an ultraviolet divergence, which is renormalized by a local effective counterterm. This counterterm contributes to the width of the neutral pion decay which determines the finite part of the counterterm coefficient. The affect of the anomaly to the Rosenbluth separation of the electromagnetic form factors as well as the discrepance regarding the polarization measurements is extensively

  6. Die Transition zur pflegenden Tochter

    Directory of Open Access Journals (Sweden)

    Dagmar Dräger

    2004-11-01

    Full Text Available Das Buch aus der Reihe „Studien zur Gesundheits- und Pflegewissenschaft“ beschreibt den theoretischen Hintergrund, das methodische Vorgehen und die Ergebnisse einer biografischen Untersuchung, die sich dem Übergang von der Tochter zur pflegenden Tochter widmete. Grundlage der Publikation ist die Dissertation (2002 der Autorin. Mit der Berücksichtigung biographischer und familiärer Hintergründe wird eine neue Perspektive in der Forschung zu pflegenden Angehörigen eingenommen.

  7. Kurzskala zur Erfassung der Unternehmenskultur

    OpenAIRE

    Jöns, Ingela; Hodapp, Markus; Weiss, Katharina

    2005-01-01

    Die Kulturskala zur Erfassung der Unternehmenskultur (KUK) fokussiert auf die Einstufung der Kultur des eigenen Unternehmens und eines anderen Unternehmens durch die Mitarbeiter, wie dies z.B. im Fall von Fusionen von Bedeutung ist. Ihre vier Dimensionen (Strategie, Struktur, Führung und Zusammenarbeit) werden anhand eines bündigen Inventars von 15 Merkmalen erfasst. In einer Untersuchung bei drei Unternehmen der Chemie- und Energiebranche mit einer Gesamtstichprobe von n = 724 konnte gezeigt...

  8. Neuer Beitrag zur Kenntnis aussereuropaeischer Trichopteren

    NARCIS (Netherlands)

    Ulmer, Georg

    1906-01-01

    In den folgenden Mitteilungen findet man alles veröffentlicht, was mir zur Zeit an neuem und wenig bekannten Materiale (mit Ausnahme amerikanischer Arten, für die mir keine Typen vorliegen) zur Verfügung steht. Herr Dr. H. W. van der Weele in Leiden war so freundlich, mir die aussereuropäischen

  9. Von der lernenden Region zur "Smart Region“

    OpenAIRE

    Poschwatta, Wolfgang

    2004-01-01

    Von der lernenden Region zur "Smart Region“ / M. Hilpert, W. Poschwatta. - In: Nabizadeh-Araghi, Nima : Auf dem Weg zur "Smart Region" : regionale Entwicklung am Beispiel der Pistazienproduktion im Iran. - Augsburg : Müllerdruck, 2004. - S. 5-9. - (Terra facta ; 2)

  10. Characterization of Zur-dependent genes and direct Zur targets in Yersinia pestis

    Directory of Open Access Journals (Sweden)

    Wang Xiaoyi

    2009-06-01

    Full Text Available Abstract Background The zinc uptake regulator Zur is a Zn2+-sensing metalloregulatory protein involved in the maintenance of bacterial zinc homeostasis. Up to now, regulation of zinc homeostasis by Zur is poorly understood in Y. pestis. Results We constructed a zur null mutant of Y. pestis biovar microtus strain 201. Microarray expression analysis disclosed a set of 154 Zur-dependent genes of Y. pestis upon exposure to zinc rich condition. Real-time reverse transcription (RT-PCR was subsequently used to validate the microarray data. Based on the 154 Zur-dependent genes, predicted regulatory Zur motifs were used to screen for potential direct Zur targets including three putative operons znuA, znuCB and ykgM-RpmJ2. The LacZ reporter fusion analysis verified that Zur greatly repressed the promoter activity of the above three operons. The subsequent electrophoretic mobility shift assay (EMSA demonstrated that a purified Zur protein was able to bind to the promoter regions of the above three operons. The DNase I footprinting was used to identify the Zur binding sites for the above three operons, verifying the Zur box sequence as predicted previously in γ-Proteobacteria. The primer extension assay was further used to determine the transcription start sites for the above three operons and to localize the -10 and -35 elements. Zur binding sites overlapped the -10 sequence of its target promoters, which was consistent with the previous observation that Zur binding would block the entry of the RNA polymerase to repress the transcription of its target genes. Conclusion Zur as a repressor directly controls the transcription of znuA, znuCB and ykgM-RpmJ2 in Y. pestis by employing a conserved mechanism of Zur-promoter DNA association as observed in γ-Proteobacteria. Zur contributes to zinc homeostasis in Y. pestis likely through transcriptional repression of the high-affinity zinc uptake system ZnuACB and two alternative ribosomal proteins YkgM and RpmJ2.

  11. Photon-photon interactions

    International Nuclear Information System (INIS)

    Gilman, F.J.

    1980-01-01

    A brief summary of the present status of photon-photon interactions is presented. Stress is placed on the use of two-photon collisions to test present ideas on the quark constituents of hadrons and on the theory of strong interactions

  12. Photon-photon collisions

    International Nuclear Information System (INIS)

    Burke, D.L.

    1982-10-01

    Studies of photon-photon collisions are reviewed with particular emphasis on new results reported to this conference. These include results on light meson spectroscopy and deep inelastic e#betta# scattering. Considerable work has now been accumulated on resonance production by #betta##betta# collisions. Preliminary high statistics studies of the photon structure function F 2 /sup #betta#/(x,Q 2 ) are given and comments are made on the problems that remain to be solved

  13. Photon-photon collisions

    International Nuclear Information System (INIS)

    Haissinski, J.

    1986-06-01

    The discussions presented in this paper deal with the following points: distinctive features of gamma-gamma collisions; related processes; photon-photon elastic scattering in the continuum and γγ →gg; total cross section; γγ → V 1 V 2 (V=vector meson); radiative width measurements and light meson spectroscopy; exclusive channels at large /t/; jets and inclusive particle distribution in γγ collisions; and, the photon structure function F γ 2

  14. Photon-photon colliders

    International Nuclear Information System (INIS)

    Sessler, A.M.

    1995-04-01

    Since the seminal work by Ginsburg, et at., the subject of giving the Next Linear Collider photon-photon capability, as well as electron-positron capability, has drawn much attention. A 1990 article by V.I. Teinov describes the situation at that time. In March 1994, the first workshop on this subject was held. This report briefly reviews the physics that can be achieved through the photon-photon channel and then focuses on the means of achieving such a collider. Also reviewed is the spectrum of backscattered Compton photons -- the best way of obtaining photons. We emphasize the spectrum actually obtained in a collider with both polarized electrons and photons (peaked at high energy and very different from a Compton spectrum). Luminosity is estimated for the presently considered colliders, and interaction and conversion-point geometries are described. Also specified are laser requirements (such as wavelength, peak power, and average power) and the lasers that might be employed. These include conventional and free-electron lasers. Finally, we describe the R ampersand D necessary to make either of these approaches viable and explore the use of the SLC as a test bed for a photon-photon collider of very high energy

  15. Der Weg von der Computerkompetenz zur Medienkompetenz

    Directory of Open Access Journals (Sweden)

    Barbara Zuliani

    2011-09-01

    Full Text Available Weiterführende Gedanken zur „Schlüsselkompetenz Nr.4“ des Europäischen Rates im Bereich des lebenslangen Lernens: Computerkompetenz bzw. Medienkompetenz, sowie Anwendungsbeispiele aus dem Bereich der Volksschule: Klassenblog und verschiedener Apps via iPad - 2 Praxisberichte

  16. Wege zur Entdeckung von Communities in Folksonomies

    OpenAIRE

    Jäschke, Robert; Hotho, Andreas; Schmitz, Christoph; Stumme, Gerd

    2006-01-01

    Ein wichtiger Baustein des neu entdeckten World Wide Web - des "Web 2.0" - stellen Folksonomies dar. In diesen Systemen können Benutzer gemeinsam Ressourcen verwalten und mit Schlagwörtern versehen. Die dadurch entstehenden begrifflichen Strukturen stellen ein interessantes Forschungsfeld dar. Dieser Artikel untersucht Ansätze und Wege zur Entdeckung und Strukturierung von Nutzergruppen ("Communities") in Folksonomies.

  17. Ein Beitrag zur Blutzellmorphologie ausgewählter karnivorer Zootierarten

    OpenAIRE

    Güth, Henrike

    2004-01-01

    Henrike Güth Ein Beitrag zur Blutzellmorphologie ausgewählter karnivorer Zootierarten Zoo Leipzig Januar 2003 156 Seiten, 222 Abbildungen, 67 Tabellen, 1 Graphik, 151 Literaturangaben, Anhang mit 25 Abbildungen und 6 Tabellen Zur Beurteilung des Blutbildes ist es nötig, neben der quantitativen Betrachtung der Blutzellen auch ihre Morphologie in die Untersuchungen einzubeziehen. In der Praxis werden dazu häufig nach May-Grünwald-Giemsa-gefärbte Ausstriche verwendet. Referenzwerte zur physiolog...

  18. Photon-photon collisions

    Energy Technology Data Exchange (ETDEWEB)

    Brodsky, S.J.

    1985-01-01

    The study of photon-photon collisions has progressed enormously, stimulated by new data and new calculational tools for QCD. In the future we can expect precise determinations of ..cap alpha../sub s/ and ..lambda../sup ms/ from the ..gamma..*..gamma.. ..-->.. ..pi../sup 0/ form factor and the photon structure function, as well as detailed checks of QCD, determination of the shape of the hadron distribution amplitudes from ..gamma gamma.. ..-->.. H anti H, reconstruction of sigma/sub ..gamma gamma../ from exclusive channels at low W/sub ..gamma gamma../, definitive studies of high p/sub T/ hadron and jet production, and studies of threshold production of charmed systems. Photon-photon collisions, along with radiative decays of the psi and UPSILON, are ideal for the study of multiquark and gluonic resonances. We have emphasized the potential for resonance formation near threshold in virtually every hadronic exclusive channel, including heavy quark states c anti c c anti c, c anti c u anti u, etc. At higher energies SLC, LEP, ...) parity-violating electroweak effects and Higgs production due to equivalent Z/sup 0/ and W/sup + -/ beams from e ..-->.. eZ/sup 0/ and e ..-->.. nu W will become important. 44 references.

  19. Photon-photon collisions

    International Nuclear Information System (INIS)

    Brodsky, S.J.

    1985-01-01

    The study of photon-photon collisions has progressed enormously, stimulated by new data and new calculational tools for QCD. In the future we can expect precise determinations of α/sub s/ and Λ/sup ms/ from the γ*γ → π 0 form factor and the photon structure function, as well as detailed checks of QCD, determination of the shape of the hadron distribution amplitudes from γγ → H anti H, reconstruction of sigma/sub γγ/ from exclusive channels at low W/sub γγ/, definitive studies of high p/sub T/ hadron and jet production, and studies of threshold production of charmed systems. Photon-photon collisions, along with radiative decays of the psi and UPSILON, are ideal for the study of multiquark and gluonic resonances. We have emphasized the potential for resonance formation near threshold in virtually every hadronic exclusive channel, including heavy quark states c anti c c anti c, c anti c u anti u, etc. At higher energies SLC, LEP, ...) parity-violating electroweak effects and Higgs production due to equivalent Z 0 and W +- beams from e → eZ 0 and e → nu W will become important. 44 references

  20. Photon-photon collisions

    International Nuclear Information System (INIS)

    Field, J.H.

    1984-01-01

    The current status, both theoretical and experimental, of two photon collision physics is reviewed with special emphasis on recent experimental results from e + e - storage rings. After a complete presentation of the helicity amplitude formalism for the general process e + e - → Xe + e - , various approximations (transverse photon, Weisaecker Williams) are discussed. Beam polarisation effects and radiative corrections are also briefly considered. A number of specific processes, for which experimental results are now available, are then described. In each case existing theoretical prediction are confronted with experimental results. The processes described include single resonance production, lepton and hadron pair production, the structure functions of the photon, the production of high Psub(T) jets and the total photon photon cross section. In the last part of the review the current status of the subject is summarised and some comments are made on future prospects. These include both extrapolations of current research to higher energy machines (LEP, HERA) as well as a brief mention of both the technical realisation and the physics interest of the real γγ and eγ collisions which may be possible using linear electron colliders in the 1 TeV energy range

  1. Untersuchung der Produktion charmhaltiger Mesonen in der Photon-Photon-Streuung mit dem OPAL-Experiment

    CERN Document Server

    Patt, Jochen

    2001-01-01

    Die Produktion von Charm-Quarks in der Photon-Photon-Streuung wird ueber den Nachweis charmhaltiger Mesonen untersucht. Die Arbeit basiert auf den Daten, die mit dem OPAL-Detektor am Elektron-Positron-Speicherring LEP am CERN in Genf in den Jahren von 1989 bis 1998 aufgenommen worden sind. Anhand des Charmonium-Zustandes Chi(c2) wird die Resonanzproduktion von Charm-Quarks untersucht und die Zwei-Photon-Breite des Chi(c2)-Mesons wird gemessen. Geladene D*-Mesonen werden zur Untersuchung der offenen Produktion von Charm-Quarks benutzt. Der Anteil des direkten und des einfach-aufgeloesten Produktionsmechanismus, differentielle D*-Wirkungsquerschnitte, der totale Charm-Wirkungsquerschnitt sowie die Charm-Strukturfunktion des Photons werden bestimmt.

  2. Sie lebt! Zur Verbraucherforschung im deutschsprachigen Raum

    DEFF Research Database (Denmark)

    Oehler, Andreas; Reisch, Lucia

    2012-01-01

    jeweils eine existierende Aktivität; eine deutliche Lücke, die es zu schließen gilt (Wachstumsfelder der Verbraucherforschung). Zur Finanzierung der Verbraucherforschung ergibt sich der deutliche Befund, dass mit weitem Abstand die „Bordmittel“ der jeweiligen Professur bzw. des jeweiligen Lehrstuhls als...... oder des BMELV darauf hindeuten, dass die Verbraucherforschung zunehmend als wichtiges Element oder gar als Voraussetzung für eine fundierte moderne Verbraucherpolitik gesehen wird....

  3. Wohnquartiersbeschreibung: ein Instrument zur Regionalisierung von Nachbarschaften

    OpenAIRE

    Hoffmeyer-Zlotnik, Jürgen H. P.

    2001-01-01

    'Ausgehend von der Annahme, daß soziale Differenzierung sich in räumlicher Differenzierung niederschlägt, bietet eine Beschreibung der Struktur des näheren Wohnumfeldes die Möglichkeit, das Wohnquartier als Handlungsraum und Sozialisationsinstanz zur Interpretation von Umfragedaten zu nutzen. Das vorliegende Instrumentarium erlaubt es, das Wohnquartier unabhängig von Zensusdaten über Merkmale, die in der eigenen Umfrage erhoben werden, zu charakterisieren.' (Autorenreferat) 'The general hy...

  4. Verfahren zur genbasierten Diagnose eines Legasthenierisikos

    OpenAIRE

    Wilcke, Arndt; Ahnert, Peter; Kirsten, Holger; Ligges, Carolin; Boltze, Johannes

    2016-01-01

    Die vorliegende Erfindung betrifft ein Verfahren zur Diagnose eines Legasthenierisikos, umfassend die Schritte: a) Bereitstellung einer Nukleinsäure beinhaltenden Probe von einem zu diagnostizierenden Menschen, b) Bestimmung des Genotyps der Nukleinsäure der Probe für mindestens eine chromosomale Region, ausgewählt aus der Gruppe bestehend aus der Region von Nukleotid 12091000 bis 12200000 des Chromosoms 1, der Region von Nukleotid 89066000 bis 89088000 des Chromosoms 15, der Region von Nukle...

  5. CONFERENCE: Photon-photon collisions

    International Nuclear Information System (INIS)

    Anon.

    1983-01-01

    Despite being difficult to observe, photon-photon collisions have opened up a range of physics difficult, or even impossible, to access by other methods. The progress which has been made in this field was evident at the fifth international workshop on photon-photon collisions, held in Aachen from 13-16 April and attended by some 120 physicists

  6. Photon technology. Hard photon technology; Photon technology. Hard photon gijutsu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-03-01

    Research results of hard photon technology have been summarized as a part of novel technology development highly utilizing the quantum nature of photon. Hard photon technology refers to photon beam technologies which use photon in the 0.1 to 200 nm wavelength region. Hard photon has not been used in industry due to the lack of suitable photon sources and optical devices. However, hard photon in this wavelength region is expected to bring about innovations in such areas as ultrafine processing and material synthesis due to its atom selective reaction, inner shell excitation reaction, and spatially high resolution. Then, technological themes and possibility have been surveyed. Although there are principle proposes and their verification of individual technologies for the technologies of hard photon generation, regulation and utilization, they are still far from the practical applications. For the photon source technology, the laser diode pumped driver laser technology, laser plasma photon source technology, synchrotron radiation photon source technology, and vacuum ultraviolet photon source technology are presented. For the optical device technology, the multi-layer film technology for beam mirrors and the non-spherical lens processing technology are introduced. Also are described the reduction lithography technology, hard photon excitation process, and methods of analysis and measurement. 430 refs., 165 figs., 23 tabs.

  7. Polychromatic photons

    DEFF Research Database (Denmark)

    Keller, Ole

    2002-01-01

    train quantum electrodynamics. A brief description of particle (photon) position operators is given, and it is shown that photons usually are only algebraically confined in an emission process. Finally, it is demonstrated that the profile of the birth domain of a radio-frequency photon emitted...

  8. Wässrige Nanosuspensionen zur pulmonalen Applikation

    OpenAIRE

    Scherließ, Holger

    2008-01-01

    Im Rahmen der vorliegenden Arbeit wurde die Entwicklung einer Nanosuspensionsformulierung zur inhalativen Anwendung mit dem schwerlöslichen Antimykotikum Itraconazol untersucht. Viele der neu entwickelten pharmazeutischen Wirkstoffe sind nach der Arzneibuchdefinition als schwerlöslich, sehr schwer löslich oder gar praktisch unlöslich einzuteilen. Das bedingt in der Praxis häufig Probleme in der Bioverfügbarkeit und stellt eine große Herausforderung für die Galenik dar. Die Herstellung der Nan...

  9. Untersuchungen zur Genauigkeit digitaler intraoraler Scans

    OpenAIRE

    Benedickt, Christopher Roland

    2017-01-01

    Ziel der hier vorliegenden In-vitro-Studie war es, zu untersuchen, ob es bei digitalen int-raoralen Scans zu Verzerrungen, Streckungen, Stauchungen, Verdrillungen oder Biegun-gen, kommt. Als Prüfmodell diente ein vollbezahntes Oberkiefermodell aus einer Chrom-Kobalt-Molybdän-Legierung. Auf diesem waren die Zähne 11, 15, 24 und 26 zur Auf-nahme eines Veneers, einer Vollkrone, eines Inlays präpariert, und auf inzisalen bezie-hungsweise okklusalen Mulden der Zähne 13, 23, 17 und 27 waren Metallk...

  10. Untersuchungen zur Rauchgasentstickung mittels Schwefelwasserstoff in Tri-n-butylphosphat

    OpenAIRE

    Homann, Jörg

    2000-01-01

    In der vorliegenden Arbeit wurde die Reaktion von Stickstoffmonoxid (NO) mit Schwefelwassersoff (H2S) in Tri-n-butylphosphat (TBP) im Hinblick auf ein alternatives Verfahren zur Entstickung von Rauchgasen untersucht. Mittels einer gasvolumetrischen Absorptionsapparatur wurden zuerst Daten zur physikalischen Löslichkeit in TBP ermittelt, die für den Erhalt kinetischer Daten der stofftransportüberlagerten Reaktionen in TBP relevant sind. Es sind dies die Henrykoeffizienten von NO, H2S und die d...

  11. Photonic Hypercrystals

    Directory of Open Access Journals (Sweden)

    Evgenii E. Narimanov

    2014-10-01

    Full Text Available We introduce a new “universality class” of artificial optical media—photonic hypercrystals. These hyperbolic metamaterials, with periodic spatial variation of dielectric permittivity on subwavelength scale, combine the features of optical metamaterials and photonic crystals. In particular, surface waves supported by a hypercrystal possess the properties of both the optical Tamm states in photonic crystals and surface-plasmon polaritons at the metal-dielectric interface.

  12. Microwave photonics

    CERN Document Server

    Lee, Chi H

    2006-01-01

    Wireless, optical, and electronic networks continue to converge, prompting heavy research into the interface between microwave electronics, ultrafast optics, and photonic technologies. New developments arrive nearly as fast as the photons under investigation, and their commercial impact depends on the ability to stay abreast of new findings, techniques, and technologies. Presenting a broad yet in-depth survey, Microwave Photonics examines the major advances that are affecting new applications in this rapidly expanding field.This book reviews important achievements made in microwave photonics o

  13. Zur interaktionistischen Theorie der mediatisierten Kommunikation

    Directory of Open Access Journals (Sweden)

    Ulrich Holefleisch

    2001-03-01

    Full Text Available Nicht nur Fachleute beklagen die mangelnde Qualität der deutschen Filme und Werbespots. Eine Ursache für die mangelnden Erfolge solcher mediatisierten Kommunikation liegt in einer systematischen Interaktionsstörung zwischen der Medienpraxis und Medienforschung. Die aktuelle deutschsprachige Medienwirkungsforschung entzieht sich weitgehend der gebotenen und von Macher/innen erwarteten gesellschafts- und praxisdienenden Aufgabe. Der Hauptgrund hierfür liegt darin, dass die zumeist zugrunde gelegten Forschungsrahmen (conceptual frameworks praxisrelevante Kategorien wie die der Zuschauerperspektive weitgehend ignorieren. Das hier vorgestellte interaktionistische Modell der mediatisierten Kommunikation will deshalb als Forschungsrahmen den Blick auf Übersehenes richten. Darüber hinaus soll dieses Modell auch für Praktiker als Prüfschema zur Mediaplanung dienen, mediatisierte Kommunikation - gemessen am eigenen Anspruch - kalkulierbarer und damit auch erfolgreicher zu machen.

  14. Photon technology. Hard photon technology; Photon technology. Hard photon gijutsu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-03-01

    For the application of photon to industrial technologies, in particular, a hard photon technology was surveyed which uses photon beams of 0.1-200nm in wavelength. Its features such as selective atom reaction, dense inner shell excitation and spacial high resolution by quantum energy are expected to provide innovative techniques for various field such as fine machining, material synthesis and advanced inspection technology. This wavelength region has been hardly utilized for industrial fields because of poor development of suitable photon sources and optical devices. The developmental meaning, usable time and issue of a hard photon reduction lithography were surveyed as lithography in ultra-fine region below 0.1{mu}m. On hard photon analysis/evaluation technology, the industrial use of analysis, measurement and evaluation technologies by micro-beam was viewed, and optimum photon sources and optical systems were surveyed. Prediction of surface and surface layer modification by inner shell excitation, the future trend of this process and development of a vacuum ultraviolet light source were also surveyed. 383 refs., 153 figs., 17 tabs.

  15. Inverse photon-photon processes

    International Nuclear Information System (INIS)

    Carimalo, C.; Crozon, M.; Kesler, P.; Parisi, J.

    1981-12-01

    We here consider inverse photon-photon processes, i.e. AB → γγX (where A, B are hadrons, in particular protons or antiprotons), at high energies. As regards the production of a γγ continuum, we show that, under specific conditions the study of such processes might provide some information on the subprocess gg γγ, involving a quark box. It is also suggested to use those processes in order to systematically look for heavy C = + structures (quarkonium states, gluonia, etc.) showing up in the γγ channel. Inverse photon-photon processes might thus become a new and fertile area of investigation in high-energy physics, provided the difficult problem of discriminating between direct photons and indirect ones can be handled in a satisfactory way

  16. Photon generator

    Science.gov (United States)

    Srinivasan-Rao, Triveni

    2002-01-01

    A photon generator includes an electron gun for emitting an electron beam, a laser for emitting a laser beam, and an interaction ring wherein the laser beam repetitively collides with the electron beam for emitting a high energy photon beam therefrom in the exemplary form of x-rays. The interaction ring is a closed loop, sized and configured for circulating the electron beam with a period substantially equal to the period of the laser beam pulses for effecting repetitive collisions.

  17. Vergleich verschiedener Methoden zur Haftkraftmessung von Dentinadhäsiven

    OpenAIRE

    Schwertner, Katharina

    2010-01-01

    Zur Bestimmung der Haftkraft von Adhäsiven stehen verschiedene Methoden zur Verfügung. Ziel dieser Studie war es, vier gebräuchliche in vitro Haftkraftmessmethoden (Tensile Bond Strength Test, Shear Bond Strength Test, Microtensile Bond Strength Test, Push-out Bond Strength Test) an drei unterschiedlichen Adhäsivsystemen (Syntac, Clearfil SE Bond, Adper Scotchbond Multi Purpose) zu testen und die Ergebnisse zu vergleichen. Die Haftkräfte sind abhängig von der verwendeten Messmethode. Viele Pa...

  18. Digitale Transformation, aber wie? - Von der Spielwiese zur Umsetzungsplanung

    Science.gov (United States)

    Kaiser, Thomas

    Es besteht wohl kaum Anlass zur Annahme, dass die seit Jahrzehnten etablierten Markt- und Technologiestrukturen der Energiewirtschaft sich nicht in einem radikalen Ablöseprozess mit Gewinnern und Verlierern befinden. Aber Vorsicht - vordergründig bereits verloren erscheinende Geschäftsmodelle erfahren im Zuge der Digitalisierung einerseits noch intensiveren Wettbewerbsdruck, können aber andererseits von diesem "technologischen Jungbrunnen" profitieren, um verlorenes Terrain zurückzugewinnen. Im folgenden Kapitel wird ein Managementzyklus aufgezeigt, der in Anlehnung an die bereits erfolgreiche Implementierung digitaler R/Evolutionen anderer Branchen aufzeigt, wie die Geschäftsleitung systematisch kostenbewusst und zielorientiert die Digitalisierung umsetzen kann.

  19. Quantum photonics

    CERN Document Server

    Pearsall, Thomas P

    2017-01-01

    This textbook employs a pedagogical approach that facilitates access to the fundamentals of Quantum Photonics. It contains an introductory description of the quantum properties of photons through the second quantization of the electromagnetic field, introducing stimulated and spontaneous emission of photons at the quantum level. Schrödinger’s equation is used to describe the behavior of electrons in a one-dimensional potential. Tunneling through a barrier is used to introduce the concept of non­locality of an electron at the quantum level, which is closely-related to quantum confinement tunneling, resonant tunneling, and the origin of energy bands in both periodic (crystalline) and aperiodic (non-crystalline) materials. Introducing the concepts of reciprocal space, Brillouin zones, and Bloch’s theorem, the determination of electronic band structure using the pseudopotential method is presented, allowing direct computation of the band structures of most group IV, group III-V, and group II-VI semiconducto...

  20. Green photonics

    International Nuclear Information System (INIS)

    Quan, Frederic

    2012-01-01

    Photonics, the broad merger of electronics with the optical sciences, encompasses such a wide swath of technology that its impact is almost universal in our everyday lives. This is a broad overview of some aspects of the industry and their contribution to the ‘green’ or environmental movement. The rationale for energy conservation is briefly discussed and the impact of photonics on our everyday lives and certain industries is described. Some opinions from industry are presented along with market estimates. References are provided to some of the most recent research in these areas. (review article)

  1. Von der Medienwirkungsbehauptung zur erziehungswissenschaftlichen Medienrezeptionsforschung. Vorschlag zur Analyse von Filmkommunikaten

    Directory of Open Access Journals (Sweden)

    Barbara Drinck

    2001-04-01

    Full Text Available Im Hinblick auf die Erforschung spezifischer Zusammenhänge von Medienkonsum und der Herausbildung von Einstellungen und Handlungen wird eine konstruktivistische Theorieorientierung plausibilisiert, indem zunächst auf den Stand der Medienwirkungsforschung eingegangen und vor dem Hintergrund einer begründeten Kritik des Wirkungsverständnisses auf die Notwendigkeit einer medienrezeptionswissenschaftlichen Forschungsalternative hingewiesen wird. Weiterhin wird der Stand der (erziehungswissenschaftlichen Medienrezeptionsforschung erörtert. Sodann werden Elemente einer konstruktivistischen Methodologie von Medienrezeptionsforschung beschrieben, die am Beispiel der Rezeption von Filmen konkretisiert werden. Dabei wird das Konzept des Kommunikates (S.J. Schmidt als Ausgangspunkt genommen, ein Vorschlag für eine Beschreibungssprache für (Film- Kommunikate entwickelt und eine Adaption des Ansatzes filmischer Narration zur Sprache gebracht.

  2. Photon Differentials

    DEFF Research Database (Denmark)

    Schjøth, Lars; Frisvad, Jeppe Revall; Erleben, Kenny

    2007-01-01

    illumination features. This is often not desirable as these may lose clarity or vanish altogether. We present an accurate method for reconstruction of indirect illumination with photon mapping. Instead of reconstructing illumination using classic density estimation on finite points, we use the correlation...

  3. Photon Rao

    Indian Academy of Sciences (India)

    Volume 2 Issue 5 May 1997 pp 69-72 Feature Article. Molecule of the Month Molecular–Chameleon: Solvatochromism at its Iridescent Best! Photon Rao · More Details Fulltext PDF. Volume 16 Issue 12 December 2011 pp 1303-1306. Molecule of the Month - Molecular-Chameleon: Solvatochromism at its Iridescent Best!

  4. Siebenjährige Follow-up-Studie zur Anwendung des spannungsfreien Vaginalbandes (TVT zur Behandlung der Stressharninkontinenz

    Directory of Open Access Journals (Sweden)

    Nilsson CG

    2005-01-01

    Full Text Available Studienzweck: Evaluierung der langfristigen Heilungs- und Spätkomplikationsraten bei Stressharninkontinenz der Frau bei Behandlung mit dem spannungsfreien Vaginalband (TVT, das anhand einer minimal-invasiven Operation eingesetzt wird. Methodik: In drei Studienzentren durchgeführte prospektive Beobachtungs- und Kohortenstudie mit ursprünglich 90 Frauen, deren primäre Stressharninkontinenz einen operativen Eingriff erforderlich machte. Zu den Bewertungsvariablen gehörten ein Vorlagentest (Pad-Test zur Messung des Uringewichts je 24 Stunden, ein Stresstest, eine visuelle Analogskala (VAS zur Beurteilung des Beschwerdegrads sowie ein Fragebogen zur Beurteilung der subjektiven Wahrnehmung des Kontinenzstatus durch die Frauen. Ergebnisse: Als Follow-up-Zeitraum wurde ein durchschnittlicher Zeitraum von 91 Monaten (78–100 Monate festgelegt. Sowohl die objektive als auch die subjektive Heilungsrate lag bei den an der Follow-up-Studie teilnehmenden 80 Frauen bei 81,3 %. Bei 7,8 % der Frauen wurde ein asymptomatischer Prolaps der Organe des kleinen Beckens, bei 6,3 % De-novo-Drangsymptome und bei 7,5 % eine rezidivierende Harnwegsinfektion festgestellt. Weitere unerwünschte Nebenwirkungen des Verfahrens wurden nicht festgestellt. Schlussfolgerung: Die Wirkung der TVT-Operation zur Behandlung der Stressharninkontinenz der Frau bleibt über einen Zeitraum von 7 Jahren erhalten.

  5. Photon Collider Physics with Real Photon Beams

    International Nuclear Information System (INIS)

    Gronberg, J; Asztalos, S

    2005-01-01

    Photon-photon interactions have been an important probe into fundamental particle physics. Until recently, the only way to produce photon-photon collisions was parasitically in the collision of charged particles. Recent advances in short-pulse laser technology have made it possible to consider producing high intensity, tightly focused beams of real photons through Compton scattering. A linear e + e - collider could thus be transformed into a photon-photon collider with the addition of high power lasers. In this paper they show that it is possible to make a competitive photon-photon collider experiment using the currently mothballed Stanford Linear Collider. This would produce photon-photon collisions in the GeV energy range which would allow the discovery and study of exotic heavy mesons with spin states of zero and two

  6. MRI methods for pulmonary ventilation and perfusion imaging; Methoden der MRT zur Ventilations- und Perfusionsbildgebung der Lunge

    Energy Technology Data Exchange (ETDEWEB)

    Sommer, G. [Universitaetsspital Basel, Klinik fuer Radiologie und Nuklearmedizin, Basel (Switzerland); Bauman, G. [Universitaetsspital Basel, Klinik fuer Radiologie und Nuklearmedizin - Radiologische Physik, Basel (Switzerland)

    2016-02-15

    Detektion frueher pathologischer Veraenderungen. Standardverfahren der bildgebenden Lungendiagnostik sind die Computertomographie (CT) zur morphologischen Darstellung und die Perfusions-/Ventilationsszintigraphie bzw. ''single photon emission computed tomography'' (SPECT) zur funktionellen Diagnostik. Zur Darstellung der Lungenventilation stehen die MRT mit hyperpolarisierten Gasen, die O{sub 2}-verstaerkte MRT, die MRT mit fluorierten Gasen und die Fourier-Dekompositions-MRT (FD-MRT) zur Verfuegung. Zur Perfusionsbestimmung koennen die dynamische kontrastmittelverstaerkte MRT (DCE-MRT), das ''arterial spin labeling'' (ASL) und die FD-MRT verwendet werden. Bildgebende Verfahren erlauben einen genaueren Einblick in die Pathophysiologie der Lungenfunktion auf regionaler Ebene. Vorteile der MRT sind die fehlende Strahlenbelastung, welche die schonende Akquisition dynamischer Daten ermoeglicht sowie die Vielfalt der verfuegbaren Kontraste und damit zugaenglichen Parameter der Lungenfunktion. Ausreichende klinische Daten existieren nur fuer bestimmte Anwendungen der DCE-MRT. Fuer die uebrigen Verfahren gibt es lediglich Machbarkeitsstudien und Fallserien mit unterschiedlichem Umfang. Hyperpolarisierte Gase sind technisch bedingt nur eingeschraenkt in der Klinik anwendbar. Ein klinischer Einsatz der genannten Verfahren sollte mit Ausnahme der DCE-MRT nur innerhalb von Studien erfolgen. (orig.)

  7. Photon absorptiometry

    International Nuclear Information System (INIS)

    Valkema, R.; Blokland, J.A.K.; Papapoulos, S.E.; Bijvoet, O.L.M.; Pauwels, E.K.J.

    1989-01-01

    Osteoporosis is a significant health problem in the western world, with important medical, social and economical consequences. Prevention and treatment require reliable methods for in vivo monitoring of the bone mineral content (BMC) and its change in time. This paper presents an overview of currently used radiological methods, based on photon absorptiometry, and their clinical applications. With recent methods based on dual energy X-ray absorptiometry accurate and precise measurements of axial BMC can be obtained. Whether this improvements allows reliable detection of small changes in BMC remains to be investigated. (Author). 95 refs.; 1 tab

  8. Entwicklung eines kontinuierlichen Verfahrens zur enzymkatalysierten Synthese eines strukturierten Triglycerides

    OpenAIRE

    Stadler, Hans-Gerhard

    2005-01-01

    Ausgangspunkt für die in der vorliegenden Arbeit durchgeführten Entwicklung eines kontinuierlichen Verfahrens zur Synthese des strukturierten Triglycerides 1,3-Oleyl-2-palmitoylglycerin war die von Schmid [Schmid 1999] entwickelte lipase-katalysierte Zwei-Schritt-Synthese für strukturierte Triglyceride vom Typ ABA [European Patent Application; EP 0 882 797 A2]. In der ersten Reaktionsstufe dieser zweistufigen Umesterung wird in einer Folgereaktion das Substrat Tripalmitin mit Hilfe ein...

  9. Offenheit: Poster zur Nacht des Wissens Hamburg 2015

    OpenAIRE

    Hapke, Thomas; Rajski, Beate; Bieler, Detlev

    2015-01-01

    Die Posterserie zum Thema Offenheit wurde von der Universitätsbibliothek der Technischen Universität Hamburg für die Nacht des Wissens am 7. November 2015 erstellt. Sie enthält die Poster Offenheit vonWissen Open Access Open Access Publizieren Offene Inhalte - Creative Commons Lizenzen TUBdok: Open Access Repository der TUHH Offene Bildung - Open Educational Resources Zur Geschichte der Offenheit des Wissens

  10. Strategien zur HLA-Typisierung mit PyrosequencingTM

    OpenAIRE

    Entz, Patricia

    2006-01-01

    Der Haupthistokompatibilitätskomplex ist durch seine biologische Funktion eine für die Diagnostik und Forschung äußerst wichtige Region im humanen Genom. Die Untersuchung von HLA-Genorten stellt ein wichtiges Instrument in der molekulargenetischen Praxis dar. Die Pyrosequencing-Technik ist gut geeignet, um kurze DNA-Abschnitte mit weitgehend bekannter Sequenz schnell und effizient zu untersuchen. Ziel dieser Arbeit war die Entwicklung von Pyrosequencing-basierten Methoden zur HLA-Typisierung....

  11. Zur Dialektik von Soft Skills und fachlicher Kompetenz

    OpenAIRE

    Jendrowiak, Hans-Werner

    2010-01-01

    [Der Autor stellt folgende Thesen zur Dialektik von Soft Skills und fachlicher Bildung auf:] 1. Soft Skills sind normale Bildungskategorien und Teil einer Allgemeinen Bildung. […] 2. Soft Skills sind als personalgebundene Kriterien auch immer schon Gegenstand bildungstheoretischer Debatten. […] 3. Soft Skills ist eine trendorientierte Bezeichnung für Bildung. […] 4. Soft Skills sind Ausdruck von Vorstellungen, Ideen und Theorien (Schulkultur, Unternehmenskultur, Unternehmensphilosophie). 5. S...

  12. Ein Beitrag zur Erweiterung von Beamforming-Methoden

    OpenAIRE

    Kern, Marcus

    2008-01-01

    Im automobilen Entwicklungsprozess haben sich akustische Messsysteme etabliert, die mit einer Anordnung von Mikrofonen, einer optischen Kamera und einer nachgeschalteten Signalverarbeitung die Schalleinfallsrichtung detektieren und dadurch die Schalldruckverteilung auf Quellorte im Fernfeld zurückrechnen und visualisieren können. Die Signalverarbeitung beruht i. A. auf dem Delay&Sum-Beamforming, deren Umsetzung im Zeit- oder Frequenzbereich erfolgt. Die Schwächen dieser Messtechnik bezüglich ...

  13. Alexandru Popa, Untersuchungen zu den römisch-barbarischen Kontakten Östlich der römischen Provinz Dacia Antiquitatis reihe 3 Abhnadlungen zur vor-und frühgeschichte, zur klassichen und provinzial-römischen archäologie und zur geschichte des altertum

    Directory of Open Access Journals (Sweden)

    Vasile Iarmulschi

    2016-06-01

    Full Text Available Review on book - Alexandru Popa, Untersuchungen zu den römisch-barbarischen Kontakten Östlich der römischen Provinz Dacia Antiquitatis reihe 3 Abhnadlungen zur vor-und frühgeschichte, zur klassichen und provinzial-römischen archäologie und zur geschichte des altertum

  14. Physics at high energy photon photon colliders

    International Nuclear Information System (INIS)

    Chanowitz, M.S.

    1994-06-01

    I review the physic prospects for high energy photon photon colliders, emphasizing results presented at the LBL Gamma Gamma Collider Workshop. Advantages and difficulties are reported for studies of QCD, the electroweak gauge sector, supersymmetry, and electroweak symmetry breaking

  15. Resonance formation in photon-photon collisions

    International Nuclear Information System (INIS)

    Gidal, G.

    1988-08-01

    Recent experimental progress on resonance formation in photon-photon collisions is reviewed with particular emphasis on the pseudoscalar and tensor nonents and on the γγ* production of spin-one resonances. 37 refs., 17 figs., 5 tabs

  16. Hadron production in photon-photon collisions

    International Nuclear Information System (INIS)

    Pandita, P.N.; Singh, Y.

    1976-01-01

    We analyze deep-inelastic photon-photon collisions via the two-photon mechanism in electron-positron (-electron) colliding beams in a form especially suitable for experimental analysis. It is shown that by a helicity analysis similar to that used in electroproduction experiments, we can separate five of the eight structure functions describing the process γ* + γ* → hadrons. The helicity cross sections for this process and for the process with one real photon (inelastic electron-photon scattering) are related to structure functions, and are evaluated using quark light-cone algebra. There are anomalous contributions to the structure functions for the inelastic electron-photon scattering which arise both in parton as well as generalized vector-meson-dominance models. This suggests a connection between these two types of models for photon-photon scattering. Further, we use vector-meson dominance to construct a sum rule for sigma/sub gamma//sub gamma/ /sub arrow-right/ from which it is estimated that roughly 20% of the cross section should be built up from higher-mass vector states. Using a spectral representation for the total transverse cross section, and the ''aligned-jet'' vector-dominance model we achieve a connection, via a ''correspondence principle,'' with the parton model for the hadron multiplicities in photon-photon collisions. We also comment on inclusive pion multiplicities and the approach to scaling for photon-photon processes in the light-cone algebra

  17. Photonic time crystals.

    Science.gov (United States)

    Zeng, Lunwu; Xu, Jin; Wang, Chengen; Zhang, Jianhua; Zhao, Yuting; Zeng, Jing; Song, Runxia

    2017-12-07

    When space (time) translation symmetry is spontaneously broken, the space crystal (time crystal) forms; when permittivity and permeability periodically vary with space (time), the photonic crystal (photonic time crystal) forms. We proposed the concept of photonic time crystal and rewritten the Maxwell's equations. Utilizing Finite Difference Time Domain (FDTD) method, we simulated electromagnetic wave propagation in photonic time crystal and photonic space-time crystal, the simulation results show that more intensive scatter fields can obtained in photonic time crystal and photonic space-time crystal.

  18. Odontologie im numismatischen Spiegel : Ein Beitrag zur Geschichte der Zahnheilkunde

    OpenAIRE

    Heckert, Gerold Rüdiger

    2006-01-01

    Obgleich Medaillen mit zahnheilkundlichen Motiven schon sehr lange vertreten sind, hat dies in der Literatur bisher wenig Beachtung gefunden. Eine eigenständige Veröffentlichung erschien 1988 herausgegeben von Ladendorf und Salaschek (Proskauer 1940), die sich aber nur mit der Reklame von Zahnärzten und für Zahnärzte auf Medaillen befasst. Dieser Publikation liegt die Zusammenstellung von Storer und der Katalog zur Sammlung Brettauer zu Grunde. In den USA führte der Gynäkologe Horatio...

  19. Technische Feuchtgebiete zur Nachreinigung von Abwasser:Stickstoff, Abwasserdesinfektion, Spurenstoffe

    OpenAIRE

    Rühmland, Sabine

    2015-01-01

    Stickstoff, Spurenstoffe und Krankheitserreger können auch in geringen Mengen Schäden in Gewässern bzw. beim Menschen verursachen. In dieser Arbeit soll geklärt werden, inwieweit das naturnahe Abwasserreinigungsverfahren der technischen Feuchtgebiete zur Nachreinigung von Abwasser geeignet ist. Dafür wurden in Berlin sieben bewachsene Bodenfilter und Abwasserteiche im techni-schen Maßstab einer Kläranlage mit Nährstoffelimination nachgeschaltet. Ein Sandfilter, ein Sandfilter mit Lehm und...

  20. Präanalytik zur HCMV-Diagnostik

    OpenAIRE

    Travers-Podmaniczky, Gabrielle

    2011-01-01

    Die kongenitale HCMV-Infektion ist der wichtigste Auslöser geistiger Retardierung viraler Genese und ist für die meisten neurosensorischen Hörstörungen nicht genetischen Ursprunges verantwortlich. Die Entwicklung neuer Strategien zur Prävention der HCMV-Infektion bei Neugeborenen ist also von höchster Dringlichkeit. Die Einführung von universellen Screeningprogrammen bei Neugeborenen könnte die frühzeitige Erkennung einer Infektion und somit einen frühen therapeutischen Einsatz ermöglichen. U...

  1. Migration und differenzierte Citizenship : Zur Post-Amerikanisierung Europas

    OpenAIRE

    Cattacin, Sandro

    2006-01-01

    Während sich Frankreich in Kopftuchdebatten in den Schulen auf seine Wurzeln rückbesinnen möchte, Deutschland an der Operationalisierung der Leitkultur herumbastelt und sich Forscherscharen an der politisch gestellten Frage abmühen, was „Integration“ bedeute, schreitet die Pluralisierung unserer Gesellschaft unbekümmert weiter. Diese Pluralisierung, die nur bedingt auf Migration zurückzuführen ist, fordert die europäischen nationalen Gesellschaften dreifach heraus. Erstens durch die ständige ...

  2. Photon-Photon Collisions -- Past and Future

    International Nuclear Information System (INIS)

    Brodsky, Stanley J.

    2005-01-01

    I give a brief review of the history of photon-photon physics and a survey of its potential at future electron-positron colliders. Exclusive hadron production processes in photon-photon and electron-photon collisions provide important tests of QCD at the amplitude level, particularly as measures of hadron distribution amplitudes. There are also important high energy γγ and eγ tests of quantum chromodynamics, including the production of jets in photon-photon collisions, deeply virtual Compton scattering on a photon target, and leading-twist single-spin asymmetries for a photon polarized normal to a production plane. Since photons couple directly to all fundamental fields carrying the electromagnetic current including leptons, quarks, W's and supersymmetric particles, high energy γγ collisions will provide a comprehensive laboratory for Higgs production and exploring virtually every aspect of the Standard Model and its extensions. High energy back-scattered laser beams will thus greatly extend the range of physics of the International Linear Collider

  3. Vom Referat bis zur Examensarbeit: Naturwissenschaftliche Texte perfekt verfassen und gestalten

    Science.gov (United States)

    Kremer, Bruno P.

    Welches Thema eignet sich für mein Referat oder meine Seminararbeit? Wie sammle ich Stoff? Wie gliedere ich den Text? Bruno P. Kremer beantwortet auf nur 200 Seiten alle wichtigen Fragen zur wissenschaftlichen Arbeit in den naturwissenschaftlichen Fächern. Dabei beschränkt er sich auf das für Studenten und Schüler wirklich notwendige Wissen und lässt jeglichen unnützen Ballast beiseite. Dieser praktische Ratgeber verhilft Ihnen zur erfolgreichen wissenschaftlichen Arbeit - vom Referat bis zur Examensarbeit.

  4. The components of the unique Zur regulon of Cupriavidus metallidurans mediate cytoplasmic zinc handling.

    Science.gov (United States)

    Bütof, Lucy; Schmidt-Vogler, Christopher; Herzberg, Martin; Große, Cornelia; Nies, Dietrich H

    2017-08-14

    Zinc is an essential trace element and at the same time it is toxic at high concentrations. In the beta-proteobacterium Cupriavidus metallidurans the highly efficient removal of surplus zinc from the periplasm is responsible for its outstanding metal resistance. Rather than having a typical Zur-dependent, high-affinity ATP-binding cassette transporter of the ABC protein superfamily for zinc uptake at low concentrations, C. metallidurans instead has the secondary zinc importer ZupT of the ZRT/IRT (ZIP) family. It is important to understand, therefore, how this zinc-resistant bacterium copes when it is exposed to low zinc concentrations. Members of the Zur regulon in C. metallidurans were identified by comparing the transcriptomes of a Δ zur mutant and its parent strain. The consensus sequence of the Zur-binding box was derived for the zupTp promoter-regulatory region using a truncation assay. The motif was used to predict possible Zur-boxes upstream of Zur regulon members. Binding of Zur to these boxes was confirmed. Two Zur-boxes upstream of the cobW 1 gene, encoding a putative zinc chaperone, proved to be required for complete repression of cobW 1 and its downstream genes in cells cultivated in mineral salts medium. A Zur box upstream of each of zur-cobW 2 , cobW 3 and zupT permitted low-expression level of these genes plus their up-regulation under zinc starvation conditions. This demonstrates a compartmentalization of zinc homeostasis in C. metallidurans with the periplasm being responsible for removal of surplus zinc and cytoplasmic components for management of zinc as an essential co-factor, with both compartments connected by ZupT. Importance Elucidating zinc homeostasis is necessary to understand both host-pathogen interactions and performance of free-living bacteria in their natural environment. Escherichia coli acquires zinc under low zinc concentrations by the Zur-controlled ZnuABC importer of the ABC superfamily, and this was also the paradigm for other

  5. Photon-photon collisions and photon structure functions at LEP

    CERN Document Server

    Patt, J

    2000-01-01

    The present knowledge of the structure of the photon based on measurements of photon structure functions is discussed. This review covers recent results on QED structure functions and on the hadronic structure function F/sub 2//sup gamma /. (13 refs).

  6. Photonic Crystals Towards Nanoscale Photonic Devices

    CERN Document Server

    Lourtioz, Jean-Michel; Berger, Vincent; Gérard, Jean-Michel; Maystre, Daniel; Tchelnokov, Alexei; Pagnoux, Dominique

    2008-01-01

    Just like the periodical crystalline potential in solid state crystals determines their properties for the conduction of electrons, the periodical structuring of photonic crystals leads to envisioning the possibility of achieving a control of the photon flux in dielectric and metallic materials. The use of photonic crystals as cages for storing, filtering or guiding light at the wavelength scale paves the way to the realization of optical and optoelectronic devices with ultimate properties and dimensions. This will contribute towards meeting the demands for greater miniaturization imposed by the processing of an ever increasing number of data. Photonic Crystals will provide students and researchers from different fields with the theoretical background required for modelling photonic crystals and their optical properties, while at the same time presenting the large variety of devices, ranging from optics to microwaves, where photonic crystals have found application. As such, it aims at building bridges between...

  7. Photonic Crystals Towards Nanoscale Photonic Devices

    CERN Document Server

    Lourtioz, Jean-Michel; Berger, Vincent; Gérard, Jean-Michel; Maystre, Daniel; Tchelnokov, Alexis

    2005-01-01

    Just like the periodical crystalline potential in solid-state crystals determines their properties for the conduction of electrons, the periodical structuring of photonic crystals leads to envisioning the possibility of achieving a control of the photon flux in dielectric and metallic materials. The use of photonic crystals as a cage for storing, filtering or guiding light at the wavelength scale thus paves the way to the realisation of optical and optoelectronic devices with ultimate properties and dimensions. This should contribute toward meeting the demands for a greater miniaturisation that the processing of an ever increasing number of data requires. Photonic Crystals intends at providing students and researchers from different fields with the theoretical background needed for modelling photonic crystals and their optical properties, while at the same time presenting the large variety of devices, from optics to microwaves, where photonic crystals have found applications. As such, it aims at building brid...

  8. Photon and photon reactions: elementary theoretical introduction

    International Nuclear Information System (INIS)

    Diu, B.

    The electromagnetic field and associated quanta, the photons, are simply and briefly studied. The conventional electromagnetism laws are recalled. Fundamental concepts such as gauge invariance, the electromagnetic current conservation, and photon behavior against the internal symmetries of strong interactions are simply introduced. Results and notations are applied to analysis of reactions where photons intervene in initial or final states (photoproduction) within the limits of amplitude properties in the conventional space-time. The helicity and invariant amplitude formalisms are compared [fr

  9. Active Photonic Crystal Waveguides

    DEFF Research Database (Denmark)

    Ek, Sara

    This thesis deals with the fabrication and characterization of active photonic crystal waveguides, realized in III-V semiconductor material with embedded active layers. The platform offering active photonic crystal waveguides has many potential applications. One of these is a compact photonic...... due to photonic crystal dispersion. The observations are explained by the enhancement of net gain by light slow down. Another application based on active photonic crystal waveguides is micro lasers. Measurements on quantum dot micro laser cavities with different mirror configurations and photonic...

  10. Semiokapitalismus und imperiale Kontrollgesellschaft Zur Digitalisierung der Produktion am Beginn des 21. Jahrhunderts

    Directory of Open Access Journals (Sweden)

    Wolfgang Neurath

    2014-12-01

    Full Text Available Wolfgang Neurath analysiert angesichts des kybernetischen Semiokapitalismus und des durch ihn entstandenen "Kognitariats" in welcher Art und Weise digitale Produktions- und Wertschöpfungsprozesse am Beginn des 21. Jahrhunderts zur Kontrolle eingesetzt werden ...

  11. Contributions to ecosystem research and environmental education III; Beitraege zur Oekosystemforschung und Umwelterziehung III

    Energy Technology Data Exchange (ETDEWEB)

    Erdmann, K H [ed.; Nauber, J [ed.

    1996-09-01

    The publication comprises the following chapters: Contributions to the implementation of findings in policy and administration; Contributions to biosphere reservations; Contributions to ecosystems research; Contributions to environmental education. The first chapter discusses environmental protection from the political point of view, while the second chapter describes biosphere reservations world-wide as well as their protection, conservation and development. (SR) [Deutsch] Die vorliegende Veroeffentlichung teilt sich in folgende Kapitel auf: Beitraege zur Umsetzung von Erkenntnissen in Politik und Verwaltung, Beitraege zu Biosphaerenreservaten, Beitraege zur Oekosystemforschung sowie Beitraege zur Umwelterziehung. Im ersten Kapitel wird der Umweltschutz von der politischen Seite aus beleuchtet. Das zweite Kapitel beschreibt verschiedene Biosphaerenreservate in der ganzen Welt und deren Schutz, Pflege und Entwicklung. Das dritte Kapitel beinhaltet Beitraege zur oekologischen Forschung. Abschliessend werden im letzten Kapitel psychologische Aspekte der Umwelterziehung dargestellt. (SR)

  12. Entwicklung und Anwendung neuer NMR-Methoden: Orientierungsmedien zur Strukturbestimmung mit anisotropen Parametern und Metabonomics

    OpenAIRE

    Büchler, Silke

    2014-01-01

    Das Ziel dieser Arbeit war die Entwicklung und Anwendung neuer Orientierungsmedien zur Strukturbestimmung mit anisotropen Parametern, sowie die Etablierung von Metabonomics-Studien an Flüssigzellkulturen und Reispflanzen.

  13. [Alfred Ritscher. Reval an der schwelle zur neuzeit. T. 2] / Paul Kaegbein

    Index Scriptorium Estoniae

    Kaegbein, Paul

    2006-01-01

    Arvustus: Ritscher, Alfred. Reval an der schwelle zur neuzeit. T. 2: Vom tode Wolters von Plettenberg bis zum Untergang des Deutschen Ordens in Livland (1535-1561). Bonn: Kulturstiftung der deutshen Vertriebenen 2001. (Historische Forschungen).

  14. Der gläserne Aschenbecher - oder - Zur Verallgemeinerung des Eulerschen Polyedersatzes

    OpenAIRE

    Gallin, P

    2009-01-01

    Eine Diskussion unter Mathematikern im Lehrerzimmer einer Kantonsschule führt zusammen mit Beiträgen der Schülerinnen und Schüler unversehens zu topologischen Einsichten, die normalerweise im Gymnasium nicht zur Sprache kommen.

  15. Altautoverwertung zwischen Staat und Markt: Bedingungen und Potentiale zur Modernisierung von Lagerhaltung und Marketing gebrauchter Autoteile

    OpenAIRE

    Lucas, Rainer

    2000-01-01

    Das Arbeitspapier diskutiert vor dem Hintergrund veränderter gesetzlicher Rahmen-und Wettbewerbsbedingungen in der Autoverwertung Ziele und Maßnahmen zurStärkung kleiner und mittelständischer Verwertungsbetriebe. Der Bereich GebrauchteAutoteile wird im Rahmen eines regionalen Fallbeispiels einer tiefergehenden Analyseunterzogen. Hieraus werden Vorschläge zur regionalen Netzwerkbildung innerhalb derBranche und neue Dienstleistungsperspektiven abgeleitet. Ein wesentliches Koope-rationsfeld ist ...

  16. Competitive Intelligence : Aufbau einer Informationsbasis und Entscheidungssystematik zur Definition strategischer Zielmärkte

    OpenAIRE

    Maffenbeier, Sina

    2010-01-01

    Im Rahmen der Globalisierung und des daraus resultierenden Wettbewerbs ist es für ein Unternehmen von zentraler Bedeutung, Wissen über die Wettbewerbssituation zu erhalten. Nicht nur zur Erschließung neuer Märkte, sondern auch zur Sicherung der Unternehmensexistenz ist eine Wettbewerbsanalyse unabdingbar. Konkurrenz- bzw. Wettbewerbsforschung wird überwiegend als „Competitive Intelligence“ bezeichnet. In diesem Sinne beschäftigt sich die vorliegende Bachelorarbeit mit einem Bereich von Compet...

  17. Photonic crystals: towards nanoscale photonic devices

    National Research Council Canada - National Science Library

    Lourtioz, J.-M

    2005-01-01

    .... From this point of view, the emergence of photonic bandgap materials and photonic crystals at the end of the 1980s can be seen as a revenge to the benefit this time of optics and electromagnetism. In the same way as the periodicity of solid state crystals determines the energy bands and the conduction properties of electrons, the periodical structur...

  18. Jet and hadron production in photon-photon collisions

    OpenAIRE

    Soldner-Rembold, Stefan

    1999-01-01

    Di-jet and inclusive charged hadron production cross-sections measured in photon-photon collisions by OPAL are compared to NLO pQCD calculations. Jet shapes measured in photon-photon scattering by OPAL, in deep-inelastic ep scattering by H1 and in photon-proton scattering by ZEUS are shown to be consistent in similar kinematic ranges. New results from TOPAZ on prompt photon production in photon-photon interactions are presented.

  19. Photonic crystal pioneer

    Science.gov (United States)

    Anscombe, Nadya

    2011-08-01

    Over the past ten years, Crystal Fiber, now part of NKT Photonics, has been busy commercializing photonic crystal fibre. Nadya Anscombe finds out about the evolution of the technology and its applications.

  20. Photonic Design for Photovoltaics

    Energy Technology Data Exchange (ETDEWEB)

    Kosten, E.; Callahan, D.; Horowitz, K.; Pala, R.; Atwater, H.

    2014-08-28

    We describe photonic design approaches for silicon photovoltaics including i) trapezoidal broadband light trapping structures ii) broadband light trapping with photonic crystal superlattices iii) III-V/Si nanowire arrays designed for broadband light trapping.

  1. Photonic crystal light source

    Science.gov (United States)

    Fleming, James G [Albuquerque, NM; Lin, Shawn-Yu [Albuquerque, NM; Bur, James A [Corrales, NM

    2004-07-27

    A light source is provided by a photonic crystal having an enhanced photonic density-of-states over a band of frequencies and wherein at least one of the dielectric materials of the photonic crystal has a complex dielectric constant, thereby producing enhanced light emission at the band of frequencies when the photonic crystal is heated. The dielectric material can be a metal, such as tungsten. The spectral properties of the light source can be easily tuned by modification of the photonic crystal structure and materials. The photonic crystal light source can be heated electrically or other heating means. The light source can further include additional photonic crystals that exhibit enhanced light emission at a different band of frequencies to provide for color mixing. The photonic crystal light source may have applications in optical telecommunications, information displays, energy conversion, sensors, and other optical applications.

  2. Photon structure function - theory

    International Nuclear Information System (INIS)

    Bardeen, W.A.

    1984-12-01

    The theoretical status of the photon structure function is reviewed. Particular attention is paid to the hadronic mixing problem and the ability of perturbative QCD to make definitive predictions for the photon structure function. 11 references

  3. Double-mode Two-photon Absorption and Enhanced Photon Antibunching Due to Interference

    Science.gov (United States)

    Bandilla, A.; Ritze, H.-H.

    Inspired by results of interfering signal and idler from a nondegenerate parametric amplifier we investigate the photon statistics of the resulting field after interference of two components subjected to double-mode two-photon absorption. This absorption process leads to a strong correlation of the participating modes, which can be used to generate fields with photon antibunching in interference experiments. In addition the photon number can be made small, which produces enhanced antibunching.Translated AbstractZwei-Photonen-Absorption aus zwei Moden und durch Interferenz verstärktes photon antibunchingDie quantenmechanische Betrachtung der Interferenz führt zu neuen Ergebnissen, wenn Felder ohne klassisches Analogon betrachtet werden. Insbesondere ergibt sich durch die Reduktion der Photonenzahl durch Interferenz eine effektive Verstärkung des Photon Antibunching, wie von den Verfassern in vorhergehenden Arbeiten gezeigt wurde. Die vorliegende Untersuchung betrachtet die Interferenz von zwei korrelierten Moden, wobei die Korrelation durch Zwei-Photonen-Absorption aus den beiden Moden zustande kommt. In jeder einzelnen Mode ergibt sich lediglich ein gewisses Bunching, wenn man mit kohärentem Licht in beiden Moden beginnt. Es wird die Interferenz der Feldstärke-Komponenten in bestimmten Polarisationsrichtungen untersucht. Zur Vereinfachung wird in den betrachteten Moden die gleiche Anfangsphotonenzahl vorausgesetzt und der Analysator auf minimale Transmittanz gebracht. Das eigentliche Signal entsteht dann durch Einführung einer endlichen Phasenverschiebung zwischen den beiden Moden. Dieses Signal zeigt Antibunching und kann in seiner Intensität beliebig variiert werden, was wegen des (1/n)-Charakters des Antibunching zu seiner Verstärkung führt. Ferner wird gezeigt, daß die zunächst für zwei linear polarisierte Moden durchgeführte Rechnung auf zwei zirkulare Moden sowie auf zwei gegenläufige Strahlen bei der dopplerfreien Zwei-Quanten-Absorption

  4. Photon wave function

    OpenAIRE

    Bialynicki-Birula, Iwo

    2005-01-01

    Photon wave function is a controversial concept. Controversies stem from the fact that photon wave functions can not have all the properties of the Schroedinger wave functions of nonrelativistic wave mechanics. Insistence on those properties that, owing to peculiarities of photon dynamics, cannot be rendered, led some physicists to the extreme opinion that the photon wave function does not exist. I reject such a fundamentalist point of view in favor of a more pragmatic approach. In my view, t...

  5. Diffusion Based Photon Mapping

    DEFF Research Database (Denmark)

    Schjøth, Lars; Fogh Olsen, Ole; Sporring, Jon

    2007-01-01

    . To address this problem we introduce a novel photon mapping algorithm based on nonlinear anisotropic diffusion. Our algorithm adapts according to the structure of the photon map such that smoothing occurs along edges and structures and not across. In this way we preserve the important illumination features......, while eliminating noise. We call our method diffusion based photon mapping....

  6. Diffusion Based Photon Mapping

    DEFF Research Database (Denmark)

    Schjøth, Lars; Olsen, Ole Fogh; Sporring, Jon

    2006-01-01

    . To address this problem we introduce a novel photon mapping algorithm based on nonlinear anisotropic diffusion. Our algorithm adapts according to the structure of the photon map such that smoothing occurs along edges and structures and not across. In this way we preserve the important illumination features......, while eliminating noise. We call our method diffusion based photon mapping....

  7. Photonic crystal fibers

    DEFF Research Database (Denmark)

    Lægsgaard, Jesper; Hansen, K P; Nielsen, M D

    2003-01-01

    Photonic crystal fibers having a complex microstructure in the transverse plane constitute a new and promising class of optical fibers. Such fibers can either guide light through total internal reflection or the photonic bandgap effect, In this paper, we review the different types and applications...... of photonic crystal fibers with particular emphasis on recent advances in the field....

  8. Recommended procedure for selection of detector systems for in vivo measurement of incorporated radioactivity; Empfehlungen zur Auswahl von Detektorsystemen zur Direktmessung der Koerperaktivitaet

    Energy Technology Data Exchange (ETDEWEB)

    Sahre, P. [Verein fuer Kernverfahrenstechnik und Analytik (VKTA) Rossendorf e.V., Dresden (Germany); Wahl, W. [GSF Forschungszentrum fuer Umwelt und Gesundheit, Neuherberg (Germany). Inst. fuer Strahlenschutz; Doerfel, H. [Forschungszentrum Karlsruhe GmbH (Germany)

    1997-12-01

    The paper presents and discusses a variety of aspects and objectives to be considered and explains the selection criteria to be applied with reference to the available detector systems. All available detector systems are shown and explained in a table. (orig./CB) [Deutsch] Zur Direktmessung der Koerperaktivitaet werden vorwiegend Halbleiter- und Szintillationsdetektoren verwendet. Bei Halbleiterdetektoren kommen der Regel HPGe-Detektoren und in Einzelfaellen auch Si(Li)-Detektoren zum Einsatz. Bei Szintillationsdetektoren werden hauptsaechlich NaI(TI)-Detektoren sowie NaI(TI)/CsI(TI)-Phoswich-Detektoren verwendet. Verschiedene Gesichtspunkte zur Auswahl von Detektorsystemen werden vorgestellt. (orig./SR)

  9. Silicon Microspheres Photonics

    International Nuclear Information System (INIS)

    Serpenguzel, A.

    2008-01-01

    Electrophotonic integrated circuits (EPICs), or alternatively, optoelectronic integrated circuit (OEICs) are the natural evolution of the microelectronic integrated circuit (IC) with the addition of photonic capabilities. Traditionally, the IC industry has been based on group IV silicon, whereas the photonics industry on group III-V semiconductors. However, silicon based photonic microdevices have been making strands in siliconizing photonics. Silicon microspheres with their high quality factor whispering gallery modes (WGMs), are ideal candidates for wavelength division multiplexing (WDM) applications in the standard near-infrared communication bands. In this work, we will discuss the possibility of using silicon microspheres for photonics applications in the near-infrared

  10. Photon correlation holography.

    Science.gov (United States)

    Naik, Dinesh N; Singh, Rakesh Kumar; Ezawa, Takahiro; Miyamoto, Yoko; Takeda, Mitsuo

    2011-01-17

    Unconventional holography called photon correlation holography is proposed and experimentally demonstrated. Using photon correlation, i.e. intensity correlation or fourth order correlation of optical field, a 3-D image of the object recorded in a hologram is reconstructed stochastically with illumination through a random phase screen. Two different schemes for realizing photon correlation holography are examined by numerical simulations, and the experiment was performed for one of the reconstruction schemes suitable for the experimental proof of the principle. The technique of photon correlation holography provides a new insight into how the information is embedded in the spatial as well as temporal correlation of photons in the stochastic pseudo thermal light.

  11. Electron and Photon ID

    CERN Document Server

    Hryn'ova, Tetiana; The ATLAS collaboration

    2017-01-01

    The identification of prompt photons and the rejection of background coming mostly from photons from hadron decays relies on the high granularity of the ATLAS calorimeter. The electron identification used in ATLAS for run 2 is based on a likelihood discrimination to separate isolated electron candidates from candidates originating from photon conversions, hadron misidentification and heavy flavor decays. In addition, isolation variables are used as further handles to separate signal and background. Several methods are used to measure with data the efficiency of the photon identification requirements, to cover a broad energy spectrum. At low energy, photons from radiative Z decays are used. In the medium energy range, similarities between electrons and photon showers are exploited using Z->ee decays. At high energy, inclusive photon samples are used. The measurement of the efficiencies of the electron identification and isolation cuts are performed with the data using tag and probe techniques with large statis...

  12. Inclusive hard processes in photon-photon and photon-proton interactions

    OpenAIRE

    Glasman, Claudia

    1999-01-01

    Measurements of jet, prompt photon, high-pT hadron and heavy quark production in photon-induced processes provide tests of QCD and are sensitive to the photon parton densities. A review of the latest experimental results in photon-photon and photon-proton interactions is presented. Next-to-leading-order QCD calculations for these measurements are discussed.

  13. Ilse von zur Mühlen. Glanz und Elend. Mythos und Wirklichkeit der Herrenhäuser im Baltikum. Begleitpublikation zur gleichnahmigen Ausstellung des Ostpreußischen Landesmuseums und der Carl-Schirren-Gesellschaft e.V. / Anja Wilhelmi

    Index Scriptorium Estoniae

    Wilhelmi, Anja, 1966-

    2014-01-01

    Arvustus: Mühlen, Ilse von zur. Glanz und Elend. Mythos und Wirklichkeit der Herrenhäuser im Baltikum. Begleitpublikation zur gleichnahmigen Ausstellung des Ostpreußischen Landesmuseums und der Carl-Schirren-Gesellschaft e.V. (1. Dezember 2012 bis 14. April 2013), Lindenberg i. Allgäu 2012

  14. Programmable Quantum Photonic Processor Using Silicon Photonics

    Science.gov (United States)

    2017-04-01

    8 Figure 6: (a) Proposed on-demand single photon source based on dynamic cavity storage . (b) Example of a gate implementation...electronic architectures tuned to implement artificial neural networks that improve upon both computational speed and energy efficiency. 3.6 All...states are in the dual- rail logic representation. Approved for Public Release; Distribution Unlimited. 6 Figure 3: Schematic of two-photon

  15. Nonlinear silicon photonics

    Science.gov (United States)

    Borghi, M.; Castellan, C.; Signorini, S.; Trenti, A.; Pavesi, L.

    2017-09-01

    Silicon photonics is a technology based on fabricating integrated optical circuits by using the same paradigms as the dominant electronics industry. After twenty years of fervid development, silicon photonics is entering the market with low cost, high performance and mass-manufacturable optical devices. Until now, most silicon photonic devices have been based on linear optical effects, despite the many phenomenologies associated with nonlinear optics in both bulk materials and integrated waveguides. Silicon and silicon-based materials have strong optical nonlinearities which are enhanced in integrated devices by the small cross-section of the high-index contrast silicon waveguides or photonic crystals. Here the photons are made to strongly interact with the medium where they propagate. This is the central argument of nonlinear silicon photonics. It is the aim of this review to describe the state-of-the-art in the field. Starting from the basic nonlinearities in a silicon waveguide or in optical resonator geometries, many phenomena and applications are described—including frequency generation, frequency conversion, frequency-comb generation, supercontinuum generation, soliton formation, temporal imaging and time lensing, Raman lasing, and comb spectroscopy. Emerging quantum photonics applications, such as entangled photon sources, heralded single-photon sources and integrated quantum photonic circuits are also addressed at the end of this review.

  16. Single-photon sources

    International Nuclear Information System (INIS)

    Lounis, Brahim; Orrit, Michel

    2005-01-01

    The concept of the photon, central to Einstein's explanation of the photoelectric effect, is exactly 100 years old. Yet, while photons have been detected individually for more than 50 years, devices producing individual photons on demand have only appeared in the last few years. New concepts for single-photon sources, or 'photon guns', have originated from recent progress in the optical detection, characterization and manipulation of single quantum objects. Single emitters usually deliver photons one at a time. This so-called antibunching of emitted photons can arise from various mechanisms, but ensures that the probability of obtaining two or more photons at the same time remains negligible. We briefly recall basic concepts in quantum optics and discuss potential applications of single-photon states to optical processing of quantum information: cryptography, computing and communication. A photon gun's properties are significantly improved by coupling it to a resonant cavity mode, either in the Purcell or strong-coupling regimes. We briefly recall early production of single photons with atomic beams, and the operation principles of macroscopic parametric sources, which are used in an overwhelming majority of quantum-optical experiments. We then review the photophysical and spectroscopic properties and compare the advantages and weaknesses of various single nanometre-scale objects used as single-photon sources: atoms or ions in the gas phase and, in condensed matter, organic molecules, defect centres, semiconductor nanocrystals and heterostructures. As new generations of sources are developed, coupling to cavities and nano-fabrication techniques lead to improved characteristics, delivery rates and spectral ranges. Judging from the brisk pace of recent progress, we expect single photons to soon proceed from demonstrations to applications and to bring with them the first practical uses of quantum information

  17. Criteria of validity in the measurement of shearing fracture toughness; Gueltigkeitskriterien zur Bestimmung von Scherbruchzaehigkeiten

    Energy Technology Data Exchange (ETDEWEB)

    Hiese, W

    2000-01-01

    The investigations aimed at the development of criteria for measuring valid shearing fracture toughness data K{sub IIc} in analogy to the measurement of mode-I fracture toughness K{sub Ie}. Details are presented, and practical recommendations are given. [German] Die Brucheigenschaften von Werkstoffen werden ueblicherweise unter Zugbeanspruchungsbedingungen (Mode-I) bestimmt. Im Anwendungsbereich der linear-elastischen Bruchmechanik bzw. des Kleinbereichsfliessens geschieht dieses in Form der Bruchzaehigkeit K{sub Ic}. Es existieren entsprechende Richtlinien zur Durchfuehrung des Tests sowie zur Registrierung und Auswertung der Daten. Diese Kriterien sind in Standards festgelegt. Empfehlungen zur Bestimmung der Bruchzaehigkeit K{sub IIc} unter ebener Scherbelastung (Mode-II) fuer Werkstoffe mit im wesentlichen linear-elastischem Verhalten existieren nicht. Im Rahmen dieser Arbeit werden durch den Vergleich der Groesse der plastischen Rissspitzenzonen im Verhaeltnis zu den Abmessungen von Probe bzw. Bauteil Kriterien zur Messung gueltiger Scherbruchzaehigkeiten K{sub IIc} analog zur Messung der Mode-I-Bruchzaehigkeit K{sub Ic} entwickelt. Der Groessenvergleich der plastischen Rissspitzenzonen fuer beide Beanspruchungsarten zeigt unter aequivalenten Beanspruchungen, d.h. K{sub II}=K{sub I}, dass bei Mode-II beanspruchten Rissen die plastischen Zonen groesser, aber die Differenzen in der Groesse der plastischen Zonen fuer die Zustaende ebener Spannung und ebener Dehnung kleiner sind als unter entsprechenden Mode-I-Beanspruchungen.

  18. Single-photon imaging

    CERN Document Server

    Seitz, Peter

    2011-01-01

    The acquisition and interpretation of images is a central capability in almost all scientific and technological domains. In particular, the acquisition of electromagnetic radiation, in the form of visible light, UV, infrared, X-ray, etc. is of enormous practical importance. The ultimate sensitivity in electronic imaging is the detection of individual photons. With this book, the first comprehensive review of all aspects of single-photon electronic imaging has been created. Topics include theoretical basics, semiconductor fabrication, single-photon detection principles, imager design and applications of different spectral domains. Today, the solid-state fabrication capabilities for several types of image sensors has advanced to a point, where uncoooled single-photon electronic imaging will soon become a consumer product. This book is giving a specialist´s view from different domains to the forthcoming “single-photon imaging” revolution. The various aspects of single-photon imaging are treated by internati...

  19. Heavy quark pair production in polarized photon-photon collisions

    International Nuclear Information System (INIS)

    Jikia, G.; Tkabladze, A.

    2000-04-01

    We present the cross sections of the heavy quark-antiquark pair production in polarized photon photon collision for the general case of photon polarizations. The numerical results for top-antitop production cross sections together with production asymmetries are obtained for linearly polarized photon-photon collisions, including QCD radiative corrections. (orig.)

  20. Photonics in South Africa

    CSIR Research Space (South Africa)

    Bollig, C

    2007-12-01

    Full Text Available : photonics, ultrafast and ultra- intense laser science (Heinrich Schwoerer, University of Stellenbosch); quantum information processing and communication (Francesco Petruccione, University of KwaZulu-Natal); medicinal chemistry and nanotechnology... of experience in diamond research, where scientists are now turning their attention to diamond for photonic devices. �ere is an active community in South Africa studying the potential of diamond as a single-photon source for applications in quantum...

  1. Integrated Microwave Photonics

    OpenAIRE

    Marpaung, David; Roeloffzen, Chris; Heideman, René; Leinse, Arne; Sales Maicas, Salvador; Capmany Francoy, José

    2013-01-01

    Microwave photonics (MWP) is an emerging field in which radio frequency (RF) signals are generated, distributed, processed and analyzed using the strength of photonic techniques. It is a technology that enables various functionalities which are not feasible to achieve only in the microwave domain. A particular aspect that recently gains significant interests is the use of photonic integrated circuit (PIC) technology in the MWP field for enhanced functionalities and robustness as well as the r...

  2. Two-photon physics

    International Nuclear Information System (INIS)

    Bardeen, W.A.

    1981-10-01

    A new experimental frontier has recently been opened to the study of two photon processes. The first results of many aspects of these reactions are being presented at this conference. In contrast, the theoretical development of research ito two photon processes has a much longer history. This talk reviews the many different theoretical ideas which provide a detailed framework for our understanding of two photon processes

  3. Review on Dark Photon

    Directory of Open Access Journals (Sweden)

    Curciarello Francesca

    2016-01-01

    Full Text Available e+e− collider experiments at the intensity frontier are naturally suited to probe the existence of a force beyond the Standard Model between WIMPs, the most viable dark matter candidates. The mediator of this new force, known as dark photon, should be a new vector gauge boson very weakly coupled to the Standard Model photon. No significant signal has been observed so far. I will report on current limits set on the coupling factor ε2 between the photon and the dark photon by e+e− collider experiments.

  4. Towards THz integrated photonics

    OpenAIRE

    Hübers, Heinz-Wilhelm

    2010-01-01

    The demonstration of an integrated terahertz transceiver featuring a quantum cascade laser and a Schottky diode mixer promises new applications for compact and convenient terahertz photonic instrumentation.

  5. Tale of two photons

    International Nuclear Information System (INIS)

    Anon.

    1994-01-01

    A very profitable spinoff from electron- positron collisions is two-photon physics. Rather than the electron and positron interacting directly via an exchanged photon, two virtual (transient) photons, one from each particle, get tangled up. With new electron-positron colliders appearing on the scene, a topical meeting on two-photon physics - 'From DAPHNE to LEP 200 and beyond' - held from 2-4 February in Paris, in the premises of the Ministry of Higher Education and Research, was particularly timely. Some 60 physicists, both experimentalists and theorists, participated, with some thirty speakers

  6. Advanced Photon Source (APS)

    Data.gov (United States)

    Federal Laboratory Consortium — The Advanced Photon Source (APS) at the U.S. Department of Energy's Argonne National Laboratoryprovides this nation's (in fact, this hemisphere's) brightest storage...

  7. Photonic Integrated Circuits

    Science.gov (United States)

    Krainak, Michael; Merritt, Scott

    2016-01-01

    Integrated photonics generally is the integration of multiple lithographically defined photonic and electronic components and devices (e.g. lasers, detectors, waveguides passive structures, modulators, electronic control and optical interconnects) on a single platform with nanometer-scale feature sizes. The development of photonic integrated circuits permits size, weight, power and cost reductions for spacecraft microprocessors, optical communication, processor buses, advanced data processing, and integrated optic science instrument optical systems, subsystems and components. This is particularly critical for small spacecraft platforms. We will give an overview of some NASA applications for integrated photonics.

  8. Single photon emission tomography

    International Nuclear Information System (INIS)

    Buvat, Irene

    2011-09-01

    The objective of this lecture is to present the single photon emission computed tomography (SPECT) imaging technique. Content: 1 - Introduction: anatomic, functional and molecular imaging; Principle and role of functional or molecular imaging; 2 - Radiotracers: chemical and physical constraints, main emitters, radioisotopes production, emitters type and imaging techniques; 3 - Single photon emission computed tomography: gamma cameras and their components, gamma camera specifications, planar single photon imaging characteristics, gamma camera and tomography; 4 - Quantification in single photon emission tomography: attenuation, scattering, un-stationary spatial resolution, partial volume effect, movements, others; 5 - Synthesis and conclusion

  9. Photon virtual bound state

    International Nuclear Information System (INIS)

    Inoue, J.; Ohtaka, K.

    2004-01-01

    We study virtual bound states in photonics, which are a vectorial extension of electron virtual bound states. The condition for these states is derived. It is found that the Mie resonant state which satisfies the condition that the size parameter is less than the angular momentum should be interpreted as a photon virtual bound state. In order to confirm the validity of the concept, we compare the photonic density of states, the width of which represents the lifetime of the photon virtual bound states, with numerical results

  10. Biomedical photonics handbook

    CERN Document Server

    Vo-Dinh, Tuan

    2003-01-01

    1.Biomedical Photonics: A Revolution at the Interface of Science and Technology, T. Vo-DinhPHOTONICS AND TISSUE OPTICS2.Optical Properties of Tissues, J. Mobley and T. Vo-Dinh3.Light-Tissue Interactions, V.V. Tuchin 4.Theoretical Models and Algorithms in Optical Diffusion Tomography, S.J. Norton and T. Vo-DinhPHOTONIC DEVICES5.Laser Light in Biomedicine and the Life Sciences: From the Present to the Future, V.S. Letokhov6.Basic Instrumentation in Photonics, T. Vo-Dinh7.Optical Fibers and Waveguides for Medical Applications, I. Gannot and

  11. Innovations for vehicle weight savings; Innovationen zur Gewichtseinsparung bei Kraftfahrzeugen

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, W.C. [Budd Technical Center, Auburn Hills, MI (United States)

    1999-04-01

    The American auto market provides an example of the conflict between government legislation calling for fuel economy and lower emissions, which can be achieved among other things by reducing vehicle weight, and other legislative initiatives on the safety front as well as the growing demands of consumers for comfort, which add weight to the vehicle. Automakers are responding by making increasing use of lightweight materials and weight-optimized vehicle concepts. Backed by years of experience with a variety of materials, The Budd Company - an American subsidiary of the Thyssen-Krupp Group - is in an excellent position to offer customized lightweight systems solutions. From conventional steel to high-strength steels, aluminum castings, sheet and extrusions through to high-quality plastics such as SMC and SRIM, lightweight solutions for auto bodies and chassis are developed and offered to the automotive industry. The lightweighting potential of these various materials is being further exploited through the use of advanced manufacturing processes, such as the hydroforming of steel and aluminum, tailored blanks made of steel, and bonding techniques for aluminum. (orig.) [German] Das Beispiel des amerikanischen Automobilmarktes zeigt die entgegengesetzten Forderungen des Gesetzgebers zur Kraftstoff- und Emissionsreduzierung, was u.a. durch eine Verringerung des Fahrzeuggewichtes zu erreichen ist, und Gesetzesinitiativen im Bereich der Fahrzeugsicherheit sowie wachsende Komfort-Ansprueche der Kunden, die zur Gewichtserhoehung fuehren, auf. Die Fahrzeughersteller reagieren hierauf mit zunehmendem Einsatz leichter Werkstoffe und gewichtsoptimierter Leichtbau-Konzepte. Im Verbund des ThyssenKrupp Konzerns ist das amerikanische Tochterunternehmen The Budd Company aufgrund ihrer jahrelangen Erfahrungen mit einer Vielzahl von Werkstoffen in der herausragenden Position, individuelle und den jeweiligen Anforderungen entsprechende Leichtbau-Systemloesungen anbieten zu koennen. Vom

  12. Photon-phonon interaction in photonic crystals

    International Nuclear Information System (INIS)

    Ueta, T

    2010-01-01

    Photon-phonon interaction on the analogy of electron-phonon interaction is considered in one-dimensional photonic crystal. When lattice vibration is artificially introduced to the photonic crystal, a governing equation of electromagnetic field is derived. A simple model is numerically analysed and the following novel phenomena are found out. The lattice vibration generates the light of frequency which added the integral multiple of the vibration frequency to that of the incident wave and also amplifies the incident wave resonantly. On a resonance, the amplification factor increases very rapidly with the number of layers increases. Resonance frequencies change with the phases of lattice vibration. The amplification phenomenon is analytically discussed for low frequency of the lattice vibration.

  13. ALICE Photon Multiplicity Detector

    CERN Multimedia

    Nayak, T

    2013-01-01

    Photon Multiplicity Detector (PMD) measures the multiplicity and spatial distribution of photons in the forward region of ALICE on a event-by-event basis. PMD is a pre-shower detector having fine granularity and full azimuthal coverage in the pseudo-rapidity region 2.3 < η < 3.9.

  14. Diffusion Based Photon Mapping

    DEFF Research Database (Denmark)

    Schjøth, Lars; Sporring, Jon; Fogh Olsen, Ole

    2008-01-01

    . To address this problem, we introduce a photon mapping algorithm based on nonlinear anisotropic diffusion. Our algorithm adapts according to the structure of the photon map such that smoothing occurs along edges and structures and not across. In this way, we preserve important illumination features, while...

  15. Integrated microwave photonics

    NARCIS (Netherlands)

    Marpaung, D.A.I.; Roeloffzen, C.G.H.; Heideman, Rene; Leinse, Arne; Sales, S.; Capmany, J.

    2013-01-01

    Microwave photonics (MWP) is an emerging field in which radio frequency (RF) signals are generated, distributed, processed and analyzed using the strength of photonic techniques. It is a technology that enables various functionalities which are not feasible to achieve only in the microwave domain. A

  16. Two Photon Distribution Amplitudes

    International Nuclear Information System (INIS)

    El Beiyad, M.; Pire, B.; Szymanowski, L.; Wallon, S.

    2008-01-01

    The factorization of the amplitude of the process γ*γ→γγ in the low energy and high photon virtuality region is demonstrated at the Born order and in the leading logarithmic approximation. The leading order two photon (generalized) distribution amplitudes exhibit a characteristic ln Q 2 behaviour and obey new inhomogeneous evolution equations

  17. Agile Photonic Crystals

    Science.gov (United States)

    2011-01-03

    75, pp. 3253-3256, Oct. 1995. [24] F. Benabid, J. C. Knight, and P. S. J. Russell, “Particle levitation and guidance in hollow-core photonic crystal...B. Mizaikoff, “Midinfrared sensors meet nanotechnology: Trace gas sensing with quantum cascade lasers inside photonic band-gap hollow waveguides

  18. Photon beam position monitor

    Science.gov (United States)

    Kuzay, Tuncer M.; Shu, Deming

    1995-01-01

    A photon beam position monitor for use in the front end of a beamline of a high heat flux and high energy photon source such as a synchrotron radiation storage ring detects and measures the position and, when a pair of such monitors are used in tandem, the slope of a photon beam emanating from an insertion device such as a wiggler or an undulator inserted in the straight sections of the ring. The photon beam position monitor includes a plurality of spaced blades for precisely locating the photon beam, with each blade comprised of chemical vapor deposition (CVD) diamond with an outer metal coating of a photon sensitive metal such as tungsten, molybdenum, etc., which combination emits electrons when a high energy photon beam is incident upon the blade. Two such monitors are contemplated for use in the front end of the beamline, with the two monitors having vertically and horizontally offset detector blades to avoid blade "shadowing". Provision is made for aligning the detector blades with the photon beam and limiting detector blade temperature during operation.

  19. Superconducting Single Photon Detectors

    NARCIS (Netherlands)

    Dorenbos, S.N.

    2011-01-01

    This thesis is about the development of a detector for single photons, particles of light. New techniques are being developed that require high performance single photon detection, such as quantum cryptography, single molecule detection, optical radar, ballistic imaging, circuit testing and

  20. Beiträge zur indogermanischen wortforschung IV

    Directory of Open Access Journals (Sweden)

    Bojan Čop

    1958-12-01

    Full Text Available »Hoffnung«, pahl. umēt bzw. ōmēt soll nach Horn, Grdr. d. npers. Etym. 26 aus ava (Präp. und dem Yerbum may- »einsenken« zusammengesetzt sein, was leider aus bedeutungsgeschichtlichen Gründen unannehmbar ist. Hübschmann, Pers. St. 17 f. erklärt das Wort für vollkommen dunkel. Die uriran. Form *ava-maiti- (Hübschmann kann nicht auf eine Zusammensetzung mit *mn-ti- »Denken, Gedanke« = ai. mati-š, aw. -maitiš zurückgehen, da eine i-Epenthese hier völlig unmöglich wäre. Man muß *-mai-ti- analysieren, es ergibt sich also eine Wurzel *mai-, idg. entweder mei dann Vollstufe in dem /i-Abstraktum wie in ai. man-ti- »Denken«, got. ana-minds »Verdacht« — oder eventuell *mēi-.

  1. Investigations on passive containment cooling; Untersuchungen zur passiven Containmentkuehlung

    Energy Technology Data Exchange (ETDEWEB)

    Knebel, J.U.; Cheng, X.; Neitzel, H.J.; Erbacher, F.J. [Forschungszentrum Karlsruhe GmbH Technik und Umwelt (Germany). Inst. fuer Angewandte Thermo- und Fluiddynamik; Hofmann, F. [Forschungszentrum Karlsruhe GmbH Technik und Umwelt (Germany). Projekt Nukleare Sicherheitsforschung

    1997-12-31

    The composite containment design for advanced LWRs that has been examined under the PASCO project is a promising design concept for purely passive decay heat removal after a severe accident. The passive cooling processes applied are natural convection and radiative heat transfer. Heat transfer through the latter process removes at an emission coefficient of 0.9 about 50% of the total heat removed via the steel containment, and thus is an essential factor. The heat transferring surfaces must have a high emission coefficient. The sump cooling concept examined under the SUCO project achieves a steady, natural convection-driven flow from the heat source to the heat sink. (orig./CB) [Deutsch] Das im PASCO Programm untersuchte Verbundcontainment fuer zukuenftige Leichtwasserreaktoren ist ein erfolgversprechendes rein passives System zur Nachwaermeabfuhr nach einem schweren Stoerfall. Die passiven Mechanismen der Waermeuebertragung sind Naturkonvektion und Waermestrahlung. Die durch Waermestrahlung uebertragene Waerme betraegt fuer einen Emissionskoeffizienten von 0.9 etwa 50% der insgesamt ueber das Stahl-Containment abgefuehrten Waerme und ist somit von entscheidender Bedeutung fuer die Nachwaermeabfuhr. Fuer die waermeuebertragenden Oberflaechen ist ein hoher Emissionkoeffizient erforderlich. Das im SUCO Programm untersuchte Sumpfkuehlkonzept realisiert eine stabile Naturkonvektionsstroemung zwischen Waermequelle und Waermesenke. (orig./DG)

  2. Optimum control strategy for phosphate elimination; Optimale Steuerstrategie zur Phosphatelimination

    Energy Technology Data Exchange (ETDEWEB)

    Heinrich, D.

    1997-12-31

    This study describes the most common phosphate elimination techniques. In the simplest cases, the chemicals are dosed according to previously established time curves. Nowadays, by contrast, dosage in proportion to quantity is largely preferred. Freight-proportional dosage will be more frequently employed in the future at plants for a population of more than 10000. Since investigations revealed that the results obtained using control systems are inferior to those obtained by means of automatic control systems, the latter are increasingly used. Even if PID control devices perform best, overshoot is not to be avoided with certainty because of the long dead time. According to the current state of knowledge, matched control and automatic control systems yield the best results. Further optimization can be achieved by driving them via a fuzzy-based system. (orig.) [Deutsch] In der vorliegenden Ausarbeitung wurden die gebraeuchlichsten Verfahren zur Phosphatelimination vorgestellt. In einfachsten Faellen wird die Dosierung nach festen Ganglinien vorgenommen. Sie wird heute weitgehend durch eine mengenproportionale Dosierung ersetzt. Frachtproportionale Dosierungen sind fuer Anlagen ueber 10.000 EW in Zukunft haeufiger zu finden. Nachdem die Untersuchungen gezeigt haben, dass Steuerungen nicht so gute Ergebnisse wie Reglungen ergaben, finden diese verstaerkt Anwendung. Auch wenn PID Regler das beste Ergebnis bringen, so kann mit Ihen wegen der langen Totzeiten ein Ueberschwingen nicht sicher vermieden werden. Nach heutiger Kenntnis erbringen aufeinander abgestimmte Steuer- und Reglungen die besten Ergebnisse. Werden sie ueber ein fuzzybasiertes System angesteuert, so ist eine weitere Optimierung gegeben. (orig.)

  3. Verbesserte Visualisierung der Koronararterien in MSCT-Daten mit direkter Vergleichbarkeit zur Angiographie

    Science.gov (United States)

    Lacalli, Christina; Jähne, Marion; Wesarg, Stefan

    In diesem Beitrag stellen wir neue, automatisierte Verfahren zur Visualisierung der Koronararterien einerseits und für eine direkte Vergleichbarkeit mit konventionellen Angiogrammen andererseits vor. Unser Ansatz umfasst Methoden für die automatische Extraktion des Herzens aus kontrastverstärkten CT-Daten, sowie für die Maskierung grosser kontrastmittelgefüllter Kavitäten des Herzens, um die Sichtbarkeit der Koronararterien bei der Darstellung mittels Volumenrendering zu verbessern. Zum direkten Vergleich mit konventionellen Angiographien wurde ein Verfahren zur automatischen Generierung von Projektionsansichten aus den CT-Daten entwickelt.

  4. Photonics in wireless transceivers

    International Nuclear Information System (INIS)

    Bogani, A.; Ghelfi, P.

    2013-01-01

    During the last few years, the cross-fertilization between photonics and radio systems has been helping to overcome some major limitations of the classical radio technologies, setting new paradigms, and promising improved performance and new applications with strong benefits for public communications and safety. In particular, photonics-based wireless systems, albeit still at research level, are moving toward a new generation of multifunctional systems able to manage the wireless communication with several different frequencies and protocols, even simultaneously while also realizing surveillance operations. Photonics matches the new requirements of flexibility for software-defined architectures, thanks to its ultra-wide bandwidths and ease of tunability, and guarantees low footprint and weight, thanks to integrated photonic technologies. Moreover, photonics also allows increased resolution and sensitivity by means of the inherent low phase noise of lasers. (author)

  5. Nonlinear Photonics 2014: introduction.

    Science.gov (United States)

    Akhmediev, N; Kartashov, Yaroslav

    2015-01-12

    International Conference "Nonlinear Photonics-2014" took place in Barcelona, Spain on July 27-31, 2014. It was a part of the "Advanced Photonics Congress" which is becoming a traditional notable event in the world of photonics. The current focus issue of Optics Express contains contributions from the participants of the Conference and the Congress. The articles in this focus issue by no means represent the total number of the congress contributions (around 400). However, it demonstrates wide range of topics covered at the event. The next conference of this series is to be held in 2016 in Australia, which is the home of many researchers working in the field of photonics in general and nonlinear photonics in particular.

  6. Almost real photons

    International Nuclear Information System (INIS)

    Fujii, H.

    1977-01-01

    High energy photon-proton scattering is expected to bring an important information on strong and electromagnetic interaction, and is discussed in this paper. When the ''mass'' of the photon is less than that of the lightest hadron, it is said ''the photon is almost real''. The photon energy is sufficiently high to check the energy dependence of the gamma-proton total cross section, even in the first stage of TRISTAN. The tagging system consists of four multi-wire proportional chambers (MWPC) and a lead glass Cerenkov counter. The energy of scattered electrons is determined with the Cerenkov counter. The equivalent-photon approximation is a useful method to obtain the counting rates. The estimation of the counting rate was made under the expected value of the total cross section. The estimated counting rate is strong enough for the experiment of the gamma-proton total cross section measurement. (Kato, T.)

  7. Method for assessing modular concepts for reformate gas processing for PEM fuel cell systems for decentral power supply; Methodik zur Bewertung modularer Konzepte zur Reformatgasaufbereitung fuer PEM-Brennstoffzellenanlagen zur dezentralen Energieversorgung

    Energy Technology Data Exchange (ETDEWEB)

    Gerber, J.

    2007-02-08

    The dissertation presents the fundamentals of hydrogen gas processing and CO gas purification methods and, on this basis, develops a method for energetic modularisation of the gas treatment process. All process stages are modelled and analyzed on the basis of mass and energy balances. The theoretical discussion of solution methods for the balance equations of the various process stages is limited to the steam reforming and CO gas purification system. Parameters are defined for energetic assessment of the process variants. The method leads to the identification of energetically optimized process variants. Its main goal is the optimum utilisation of process-internal energy and mass flows. The graphic pinch method is a key component of the method presented; it is adapted to the exemplary process. [German] In der Dissertation wird, ausgehend von der Darstellung der Grundlagen der Wasserstoffgasaufbereitungs- und CO-Gasreinigungsverfahren, eine Methodik zur energetischen Modularisierung des Gasaufbereitungsprozesses entwickelt. Die Modellierung und Analyse der einzelnen Prozessstufen erfolgt auf der Basis von Masse- und Energiebilanzen. Die theoretische Darstellung der Loesungsmethoden fuer die Bilanzgleichungen der einzelnen Prozessstufen ist dabei auf das System Dampfreformierung und CO-Gasreinigung eingegrenzt. Parameter zur energetischen Bewertung der Prozessvarianten werden definiert. Die Methodik fuehrt zur Eingrenzung energetisch optimierter Prozessvarianten. Ihr Hauptziel liegt in der optimalen Nutzung prozessinterner Energie- und Stoffstroeme. Ein zentraler Bestandteil der Methodik ist die graphische Pinch-Methode. Sie wird dem vorliegenden Prozess angepasst.

  8. Progress in neuromorphic photonics

    Science.gov (United States)

    Ferreira de Lima, Thomas; Shastri, Bhavin J.; Tait, Alexander N.; Nahmias, Mitchell A.; Prucnal, Paul R.

    2017-03-01

    As society's appetite for information continues to grow, so does our need to process this information with increasing speed and versatility. Many believe that the one-size-fits-all solution of digital electronics is becoming a limiting factor in certain areas such as data links, cognitive radio, and ultrafast control. Analog photonic devices have found relatively simple signal processing niches where electronics can no longer provide sufficient speed and reconfigurability. Recently, the landscape for commercially manufacturable photonic chips has been changing rapidly and now promises to achieve economies of scale previously enjoyed solely by microelectronics. By bridging the mathematical prowess of artificial neural networks to the underlying physics of optoelectronic devices, neuromorphic photonics could breach new domains of information processing demanding significant complexity, low cost, and unmatched speed. In this article, we review the progress in neuromorphic photonics, focusing on photonic integrated devices. The challenges and design rules for optoelectronic instantiation of artificial neurons are presented. The proposed photonic architecture revolves around the processing network node composed of two parts: a nonlinear element and a network interface. We then survey excitable lasers in the recent literature as candidates for the nonlinear node and microring-resonator weight banks as the network interface. Finally, we compare metrics between neuromorphic electronics and neuromorphic photonics and discuss potential applications.

  9. Single photons on demand

    International Nuclear Information System (INIS)

    Grangier, P.; Abram, I.

    2004-01-01

    Quantum cryptography and information processing are set to benefit from developments in novel light sources that can emit photons one by one. Quantum mechanics has gained a reputation for making counter-intuitive predictions. But we rarely get the chance to witness these effects directly because, being humans, we are simply too big. Take light, for example. The light sources that are familiar to us, such as those used in lighting and imaging or in CD and DVD players, are so huge that they emit billions and billions of photons. But what if there was a light source that emitted just one photon at a time? Over the past few years, new types of light source that are able to emit photons one by one have been emerging from laboratories around the world. Pulses of light composed of a single photon correspond to power flows in the femtowatt range - a million billion times less than that of a table lamp. The driving force behind the development of these single-photon sources is a range of novel applications that take advantage of the quantum nature of light. Quantum states of superposed and entangled photons could lead the way to guaranteed-secure communication, to information processing with unprecedented speed and efficiency, and to new schemes for quantum teleportation. (U.K.)

  10. Total photon absorption

    International Nuclear Information System (INIS)

    Carlos, P.

    1985-06-01

    The present discussion is limited to a presentation of the most recent total photonuclear absorption experiments performed with real photons at intermediate energy, and more precisely in the region of nucleon resonances. The main sources of real photons are briefly reviewed and the experimental procedures used for total photonuclear absorption cross section measurements. The main results obtained below 140 MeV photon energy as well as above 2 GeV are recalled. The experimental study of total photonuclear absorption in the nuclear resonance region (140 MeV< E<2 GeV) is still at its beginning and some results are presented

  11. Photonics: Technology project summary

    Science.gov (United States)

    Depaula, Ramon P.

    1991-01-01

    Photonics involves the use of light (photons) in conjunction with electronics for applications in communications, computing, control, and sensing. Components used in photonic systems include lasers, optical detectors, optical wave guide devices, fiber optics, and traditional electronic devices. The goal of this program is to develop hybrid optoelectronic devices and systems for sensing, information processing, communications, and control. It is hoped that these new devices will yield at least an order of magnitude improvement in performance over existing technology. The objective of the program is to conduct research and development in the following areas: (1) materials and devices; (2) networking and computing; (3) optical processing/advanced pattern recognition; and (4) sensing.

  12. Physics of photonic devices

    CERN Document Server

    Chuang, Shun Lien

    2009-01-01

    The most up-to-date book available on the physics of photonic devices This new edition of Physics of Photonic Devices incorporates significant advancements in the field of photonics that have occurred since publication of the first edition (Physics of Optoelectronic Devices). New topics covered include a brief history of the invention of semiconductor lasers, the Lorentz dipole method and metal plasmas, matrix optics, surface plasma waveguides, optical ring resonators, integrated electroabsorption modulator-lasers, and solar cells. It also introduces exciting new fields of research such as:

  13. Single photon ECT

    International Nuclear Information System (INIS)

    Maeda, Toshio; Matsuda, Hiroshi; Tada, Akira; Bunko, Hisashi; Koizumi, Kiyoshi

    1982-01-01

    The detectability of lesions located deep in a body or overlapped with a physiologically increased activity improve with the help of single photon ECT. In some cases, the ECT is superior to the conventional gamma camera images and X-ray CT scans in the evaluation of the location and size of lesion. The single photon ECT of the brain compares favorably with the contrast enhansed X-ray CT scans. The most important adaptation of the single photon ECT are the detection of recurrent brain tumors after craniotomy and the evaluation of ischemic heart diseases. (author)

  14. Strained Silicon Photonics

    Directory of Open Access Journals (Sweden)

    Ralf B. Wehrspohn

    2012-05-01

    Full Text Available A review of recent progress in the field of strained silicon photonics is presented. The application of strain to waveguide and photonic crystal structures can be used to alter the linear and nonlinear optical properties of these devices. Here, methods for the fabrication of strained devices are summarized and recent examples of linear and nonlinear optical devices are discussed. Furthermore, the relation between strain and the enhancement of the second order nonlinear susceptibility is investigated, which may enable the construction of optically active photonic devices made of silicon.

  15. Photonic Crystal Fibres

    DEFF Research Database (Denmark)

    Bjarklev, Anders Overgaard; Broeng, Jes; Sanchez Bjarklev, Araceli

    Photonic crystal fibres represent one of the most active research areas today in the field of optics. The diversity of applications that may be addressed by these fibres and their fundamental appeal, by opening up the possibility of guiding light in a radically new way compared to conventional...... optical fibres, have spun an interest from almost all areas of optics and photonics. The aim of this book is to provide an understanding of the different types of photonic crystal fibres and to outline some of the many new and exciting applications that these fibres offer. The book is intended for both...

  16. Fundamentals of photonics

    CERN Document Server

    Saleh, Bahaa E A

    2007-01-01

    Now in a new full-color edition, Fundamentals of Photonics, Second Edition is a self-contained and up-to-date introductory-level textbook that thoroughly surveys this rapidly expanding area of engineering and applied physics. Featuring a logical blend of theory and applications, coverage includes detailed accounts of the primary theories of light, including ray optics, wave optics, electromagnetic optics, and photon optics, as well as the interaction of photons and atoms, and semiconductor optics. Presented at increasing levels of complexity, preliminary sections build toward more advan

  17. Pflicht zur Prüfung der Existenz des Internen Kontrollsystems: Bestandesaufnahme zur Steuerung und Kontrolle mittelgrosser Unternehmen in der Schweiz

    OpenAIRE

    Ruud, T F; Isufi, S; Friebe, P

    2008-01-01

    Die Pflicht zur Prüfung der Existenz des internen Kontrollsystems betrifft auch etliche mittelgrosse Unternehmen. Im Rahmen einer Umfrage haben das Institut für Rechnungswesen und Controlling der Universität Zürich und PricewaterhouseCoopers bei diesen Unternehmen eine Bestandesaufnahme zu Kontroll- und Prüfungsaktivitäten durchgeführt. Nachstehend werden die Ergebnisse der Umfrage zum internen Kontrollsystem präsentiert.

  18. Tomography of photon-added and photon-subtracted states

    NARCIS (Netherlands)

    Bazrafkan, MR; Man'ko, [No Value

    The purpose of this paper is to introduce symplectic and optical tomograms of photon-added and photon-subtracted quantum states. Explicit relations for the tomograms of photon-added and photon-subtracted squeezed coherent states and squeezed number states are obtained. Generating functions for the

  19. Hadronic photon-photon interactions at high energies

    International Nuclear Information System (INIS)

    Engel, R.; Siegen Univ.; Ranft, J.

    1996-01-01

    Photon-photon collisions are investigated in the framework of the two-component Dual Parton Model. The model contains contributions from direct, resolved soft and resolved hard interactions. All free parameters of the model are determined in fits to hadron-hadron and photon-hadron cross section data. The model is shown to agree well to hadron production data from hadron-hadron and photon-hadron collisions. The multiparticle production in hadron-hadron, photon-hadron and photon-photon collisions as predicted by the model is compared. Strong differences are only found as function of the transverse momentum variable. (author)

  20. Microwave background constraints on mixing of photons with hidden photons

    International Nuclear Information System (INIS)

    Mirizzi, Alessandro; Redondo, Javier; Sigl, Guenter

    2008-12-01

    Various extensions of the Standard Model predict the existence of hidden photons kinetically mixing with the ordinary photon. This mixing leads to oscillations between photons and hidden photons, analogous to the observed oscillations between different neutrino flavors. In this context, we derive new bounds on the photon-hidden photon mixing parameters using the high precision cosmic microwave background spectral data collected by the Far Infrared Absolute Spectrophotometer instrument on board of the Cosmic Background Explorer. Requiring the distortions of the CMB induced by the photon-hidden photon mixing to be smaller than experimental upper limits, this leads to a bound on the mixing angle χ 0 -7 - 10 -5 for hidden photon masses between 10 -14 eV and 10 -7 eV. This low-mass and low-mixing region of the hidden photon parameter space was previously unconstrained. (orig.)

  1. Microwave background constraints on mixing of photons with hidden photons

    Energy Technology Data Exchange (ETDEWEB)

    Mirizzi, Alessandro [Max-Planck-Institut fuer Physik, Muenchen (Germany); Redondo, Javier [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Sigl, Guenter [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik

    2008-12-15

    Various extensions of the Standard Model predict the existence of hidden photons kinetically mixing with the ordinary photon. This mixing leads to oscillations between photons and hidden photons, analogous to the observed oscillations between different neutrino flavors. In this context, we derive new bounds on the photon-hidden photon mixing parameters using the high precision cosmic microwave background spectral data collected by the Far Infrared Absolute Spectrophotometer instrument on board of the Cosmic Background Explorer. Requiring the distortions of the CMB induced by the photon-hidden photon mixing to be smaller than experimental upper limits, this leads to a bound on the mixing angle {chi}{sub 0}

  2. Einfalt der Vielfalt. Zur Heterogenität als neuer Norm der (Sexual-)Pädagogik

    OpenAIRE

    Dammer, Karl-Heinz

    2015-01-01

    Der Autor befasst sich mit der aktuellen Diskussion zur Schulentwicklung in Baden-Württemberg. Diese dreht sich um den Versuch, in den schulischen Lehrplan die sexuelle Vielfalt zum Thema zu machen. Dem Autor geht es dabei um die sexualpädagogischen Konsequenzen des Diversitätsdiskurses im Hinblick auf Heterogenität und ideologischen Implikationen von Normierung. (DIPF/JS)

  3. [Heinz von zur Mühlen. Auf den Spuren einiger revlaer Firmen und Familien] / Paul Kaegbein

    Index Scriptorium Estoniae

    Kaegbein, Paul

    2007-01-01

    Arvustus: Heinz von zur Mühlen. Auf den Spuren einiger revlaer Firmen und Familien. In : Buch und Bildung im Baltikum. Münster : LIT, 2005, lk. 527-541. Pika tänava majade omanikest alates 17. sajandist - perekonnad Koch, Meyer, Kluge, Ströhm, Wassermann, Glehn, Eggers, Koppelson, Weiss. Nii loob autor pildi Tallinna "firmade ajaloost"

  4. Folgebewertung im vorratsvermögen - Fallstudie zur Vorgehensweise nach IFSR und HGB

    DEFF Research Database (Denmark)

    Quick, Reiner; Warming-Rasmussen, Bent

    2013-01-01

    über die wichstigsten Normen zur Folgebeweriung nach IFSR und HGB sowie zu deren Auslegung. Es schliessen sich ein Fallbeispiel und ein Vorschlag zu dessen Lösung an, in dessen Mittelpunkt sinkende Zeitwerte, die Frage des für die Folgebewerunng relevanten Markts und das Zuschreibungsgebot stehen....

  5. Eine selbstkonsistente Carleman Linearisierung zur Analyse von Oszillatoren

    Directory of Open Access Journals (Sweden)

    H. Weber

    2017-09-01

    Full Text Available Die Analyse nichtlinearer dynamischer Schaltungen ist bis heute eine herausfordernde Aufgabe, da nur selten analytische Lösungen angegeben werden können. Daher wurden eine Vielzahl von Methoden entwickelt, um eine qualitative oder quantitative Näherung für die Lösungen der Netzwerkgleichung zu erhalten. Oftmals wird beispielsweise eine Kleinsignalanalyse mit Hilfe einer Taylorreihe in einem Arbeitspunkt durchgeführt, die nach den Gliedern erster Ordnung abgebrochen wird. Allerdings ist diese Linearisierung nur in der Nähe des stabilen Arbeitspunktes für hyperbolische Systeme gültig. Besonders für die Analyse des dynamischen Verhaltens von Oszillatoren treten jedoch nicht-hyperbolische Systeme auf, sodass diese Methode nicht angewendet werden kann Mathis(2000. Carleman hat gezeigt, dass nichtlineare Differentialgleichungen mit polynomiellen Nichtlinearitäten in ein unendliches System von linearen Differentialgleichungen transformiert werden können Carleman(1932. Wird das unendlichdimensionale Gleichungssystem für numerische Zwecke abgebrochen, kann bei Oszillatoren der Übergang in eine stationäre Schwingung (Grenzzyklus nicht wiedergegeben werden.In diesem Beitrag wird eine selbstkonsistente Carleman Linearisierung zur Untersuchung von Oszillatoren vorgestellt, die auch dann anwendbar ist, wenn die Nichtlinearitäten keinen Polynomen entsprechen. Anstelle einer linearen Näherung um einen Arbeitspunkt, erfolgt mit Hilfe der Carleman Linearisierung eine Approximation auf einem vorgegebenen Gebiet. Da es jedoch mit der selbstkonsistenten Technik nicht möglich ist, das stationäre Verhalten von Oszillatoren zu beschreiben, wird die Berechnung einer Poincaré-Abbildung durchgeführt. Mit dieser ist eine anschließende Analyse des Oszillators möglich.

  6. Eine selbstkonsistente Carleman Linearisierung zur Analyse von Oszillatoren

    Science.gov (United States)

    Weber, Harry; Mathis, Wolfgang

    2017-09-01

    Die Analyse nichtlinearer dynamischer Schaltungen ist bis heute eine herausfordernde Aufgabe, da nur selten analytische Lösungen angegeben werden können. Daher wurden eine Vielzahl von Methoden entwickelt, um eine qualitative oder quantitative Näherung für die Lösungen der Netzwerkgleichung zu erhalten. Oftmals wird beispielsweise eine Kleinsignalanalyse mit Hilfe einer Taylorreihe in einem Arbeitspunkt durchgeführt, die nach den Gliedern erster Ordnung abgebrochen wird. Allerdings ist diese Linearisierung nur in der Nähe des stabilen Arbeitspunktes für hyperbolische Systeme gültig. Besonders für die Analyse des dynamischen Verhaltens von Oszillatoren treten jedoch nicht-hyperbolische Systeme auf, sodass diese Methode nicht angewendet werden kann Mathis (2000). Carleman hat gezeigt, dass nichtlineare Differentialgleichungen mit polynomiellen Nichtlinearitäten in ein unendliches System von linearen Differentialgleichungen transformiert werden können Carleman (1932). Wird das unendlichdimensionale Gleichungssystem für numerische Zwecke abgebrochen, kann bei Oszillatoren der Übergang in eine stationäre Schwingung (Grenzzyklus) nicht wiedergegeben werden. In diesem Beitrag wird eine selbstkonsistente Carleman Linearisierung zur Untersuchung von Oszillatoren vorgestellt, die auch dann anwendbar ist, wenn die Nichtlinearitäten keinen Polynomen entsprechen. Anstelle einer linearen Näherung um einen Arbeitspunkt, erfolgt mit Hilfe der Carleman Linearisierung eine Approximation auf einem vorgegebenen Gebiet. Da es jedoch mit der selbstkonsistenten Technik nicht möglich ist, das stationäre Verhalten von Oszillatoren zu beschreiben, wird die Berechnung einer Poincaré-Abbildung durchgeführt. Mit dieser ist eine anschließende Analyse des Oszillators möglich.

  7. Barrierefreiheit zur Routine machen – Praxisfall: Digitale Bibliothek

    Directory of Open Access Journals (Sweden)

    Susanne Baudisch

    2015-04-01

    Full Text Available Sechs Jahre sind vergangen seit Deutschland am 24. Februar 2009 die Behindertenrechtskonvention der Vereinten Nationen (BRK, die die volle Teilhabe aller Menschen an der Gesellschaft als Menschenrecht festschreibt, ratifizierte. Bereits seit 2002 gibt es in Deutschland ein Behindertengleichstellungsgesetz (BGG, den barrierefreien Zugang zu Informations- und Kommunikationstechnologien regelt die Barrierefreie Informationstechnik-Verordnung (BITV. Aus Sicht des Gesetzgebers sind die Rahmenbedingungen gegeben, Barrierefreiheit gehört inzwischen zum gängigen Vokabular im öffentlichen und teils auch privatwirtschaftlichen Bereich. Längst möchte man meinen, es sei ein alter Hut, Barrierefreiheit als Kernanliegen zu thematisieren oder gar einzufordern. Dies betrifft auch den rasant wachsenden Bereich digitaler Medien, der Wissen und Bildung für jedermann verfügbar macht - oder machen sollte. Vor diesem Hintergrund stellen sich die Autoren der Frage, inwieweit Barrierefreiheit in den digitalen Angeboten wissenschaftlicher und öffentlicher Bibliotheken in Deutschland angekommen ist; ob diese Angebote tatsächlich von allen genutzt werden können. Ausgehend von rechtlichen Grundlagen und Normen werden Formate und Standards für barrierefreie Netzpublikationen an Beispielen diskutiert. Im Fokus stehen einerseits Werkzeuge zum Suchen und Finden digitaler Information (Kataloge und Rechercheoberflächen, andererseits Ausgabeformate digitaler Dokumente (wie XML, PDF, EPUB oder TEI. Den Abschluss bilden Empfehlungen für (Digitale Bibliotheken und deren Verbände, um Barrierefreiheit künftig zur Routine zu machen. Das Fazit: Barrierefreiheit muss gewollt, geplant und sinnvoll umgesetzt werden. Technische Komponenten sind ein wichtiger, doch meist erst der zweite Schritt.

  8. Microwave photonics shines

    Science.gov (United States)

    Won, Rachel

    2011-12-01

    The combination of microwave photonics and optics has advanced many applications in defence, wireless communications, imaging and network infrastructure. Rachel Won talks to Jianping Yao from the University of Ottawa in Canada about the importance of this growing field.

  9. Photon induced reactions

    International Nuclear Information System (INIS)

    Mecking, B.A.

    1982-04-01

    Various aspects of medium energy nuclear reactions induced by real photons are reviewed. Special emphasis is put on high accuracy experiments that will become possible with the next generation of electron accelerators. (orig.)

  10. Photons and magnetization

    Czech Academy of Sciences Publication Activity Database

    Pile, P.; Němec, P.; Jungwirth, Tomáš

    2013-01-01

    Roč. 7, č. 6 (2013), s. 500 ISSN 1749-4885 Institutional support: RVO:68378271 Keywords : spintronics * photonics * magneto-optics Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 29.958, year: 2013

  11. Photonic Crystal Nanocavity Arrays

    National Research Council Canada - National Science Library

    Altug, Hatice; Vuckovic, Jelena

    2006-01-01

    We recently proposed two-dimensional coupled photonic crystal nanocavity arrays as a route to achieve a slow-group velocity of light in all crystal directions, thereby enabling numerous applications...

  12. Photonic Crystal Fibers

    National Research Council Canada - National Science Library

    Kristiansen, Rene E

    2005-01-01

    This report results from a contract tasking Crystal Fibre A/S as follows: Crystal Fibre will conduct research and development of large mode area, dual clad multi-core Yb-doped photonic crystal fiber...

  13. Principles of photonics

    CERN Document Server

    Liu, Jia-Ming

    2016-01-01

    With this self-contained and comprehensive text, students will gain a detailed understanding of the fundamental concepts and major principles of photonics. Assuming only a basic background in optics, readers are guided through key topics such as the nature of optical fields, the properties of optical materials, and the principles of major photonic functions regarding the generation, propagation, coupling, interference, amplification, modulation, and detection of optical waves or signals. Numerous examples and problems are provided throughout to enhance understanding, and a solutions manual containing detailed solutions and explanations is available online for instructors. This is the ideal resource for electrical engineering and physics undergraduates taking introductory, single-semester or single-quarter courses in photonics, providing them with the knowledge and skills needed to progress to more advanced courses on photonic devices, systems and applications.

  14. Photonic Quantum Information Processing

    International Nuclear Information System (INIS)

    Walther, P.

    2012-01-01

    The advantage of the photon's mobility makes optical quantum system ideally suited for delegated quantum computation. I will present results for the realization for a measurement-based quantum network in a client-server environment, where quantum information is securely communicated and computed. Related to measurement-based quantum computing I will discuss a recent experiment showing that quantum discord can be used as resource for the remote state preparation, which might shine new light on the requirements for quantum-enhanced information processing. Finally, I will briefly review recent photonic quantum simulation experiments of four frustrated Heisenberg-interactions spins and present an outlook of feasible simulation experiments with more complex interactions or random walk structures. As outlook I will discuss the current status of new quantum technology for improving the scalability of photonic quantum systems by using superconducting single-photon detectors and tailored light-matter interactions. (author)

  15. Possible nonvanishing mass of photon

    International Nuclear Information System (INIS)

    Nakazato, Hiromichi; Namiki, Mikio; Yamanaka, Yoshiya; Yokoyama, Kan-ichi.

    1985-05-01

    From phenomenological and field-theoretical considerations on photon mass, we first show that photon is not limitted to being massless at the present stage. Next we illustrate a possibility of formulating a local field theory for massive photons coupled with nonconserved currents, while we cannot do for massless photons. (author)

  16. The photon collider at TESLA

    Czech Academy of Sciences Publication Activity Database

    Badelek, B.; Bloechinger, C.; Blümlein, J.; Boos, E.; Brinkman, R.; Burkhardt, H.; Bussey, P.; Carimalo, C.; Chýla, Jiří; Ciftci, A.K.

    2004-01-01

    Roč. 19, č. 30 (2004), s. 5097-5186 ISSN 0217-751X Institutional research plan: CEZ:AV0Z1010920 Keywords : photon collider * linear collider * gamma-gamma * photon-photon * photon electron * Compton scattering Subject RIV: BF - Elementary Particles and High Energy Physics Impact factor: 1.054, year: 2004

  17. ALICE photon spectrometer crystals

    CERN Multimedia

    Maximilien Brice

    2006-01-01

    Members of the mechanical assembly team insert the last few crystals into the first module of ALICE's photon spectrometer. These crystals are made from lead-tungstate, a crystal as clear as glass but with nearly four times the density. When a high-energy particle passes through one of these crystals it will scintillate, emitting a flash of light allowing the energy of photons, electrons and positrons to be measured.

  18. Photon structure function

    International Nuclear Information System (INIS)

    Bardeen, W.A.

    1980-11-01

    Theoretical understanding of the photon structure function is reviewed. As an illustration of the pointlike component, the parton model is briefly discussed. However, the systematic study of the photon structure function is presented through the framework of the operator product expansion. Perturbative QCD is used as the theoretical basis for the calculation of leading contributions to the operator product expansion. The influence of higher order QCD effects on these results is discussed. Recent results for the polarized structure functions are discussed

  19. Hard processes in photon-photon interactions

    International Nuclear Information System (INIS)

    Duchovni, E.

    1985-03-01

    In this thesis, the existence of hard component in two-photon collisions is investigated. Due to the relative simplicity of the photon, such processes can be exactly calculated in QCD. Untagged (low Q 2 ) two-photon events are used. This leads to relatively high statistics, but to severe background problem due mainly to e + e - annihilation. The background contamination is reduced to a tolerable level using a special set of cuts. Moreover, the remaining contamination is shown to be calculable with a small systematic error. A large number of events of the hard ''γγ'' type is found. An attempt to explain these events using the simplest QCD diagram (the Born term) is done. This process is found to be capable of explaining only a 1/4 of the data. Other options like the constituent intercharge model, integer charged quarks, and higher order diagrams are therefore also discussed. The large cross-section for the production of ρ 0 ρ 0 pairs in ''γγ'' collisions has not been understood yet. Inorder to look at closely related processes, a search for φρ 0 and φφ was initiated. The cross-section for θπ + π - was found to be sizeable. Only upper limits for the production of φρ 0 and φφ are obtained

  20. Single-photon imaging

    International Nuclear Information System (INIS)

    Seitz, Peter; Theuwissen, Albert J.P.

    2011-01-01

    The acquisition and interpretation of images is a central capability in almost all scientific and technological domains. In particular, the acquisition of electromagnetic radiation, in the form of visible light, UV, infrared, X-ray, etc. is of enormous practical importance. The ultimate sensitivity in electronic imaging is the detection of individual photons. With this book, the first comprehensive review of all aspects of single-photon electronic imaging has been created. Topics include theoretical basics, semiconductor fabrication, single-photon detection principles, imager design and applications of different spectral domains. Today, the solid-state fabrication capabilities for several types of image sensors has advanced to a point, where uncooled single-photon electronic imaging will soon become a consumer product. This book is giving a specialist's view from different domains to the forthcoming ''single-photon imaging'' revolution. The various aspects of single-photon imaging are treated by internationally renowned, leading scientists and technologists who have all pioneered their respective fields. (orig.)

  1. Review: Holger Stoecker: Afrikawissenschaften in Berlin von 1919 bis 1945. Zur Geschichte und Topographie eines wissenschaftlichen Netzwerkes (2008 Buchbesprechung: Holger Stoecker: Afrikawissenschaften in Berlin von 1919 bis 1945. Zur Geschichte und Topographie eines wissenschaftlichen Netzwerkes

    Directory of Open Access Journals (Sweden)

    Katrin Bromber

    2009-05-01

    Full Text Available Review of the monograph: Holger Stoecker: Afrikawissenschaften in Berlin von 1919 bis 1945. Zur Geschichte und Topographie eines wissenschaftlichen Netzwerkes, Stuttgart: Franz Steiner Verlag 2008, ISBN 978-3-515-09161-9, 359 pages. Besprechung der Monographie: Holger Stoecker: Afrikawissenschaften in Berlin von 1919 bis 1945. Zur Geschichte und Topographie eines wissenschaftlichen Netzwerkes, Stuttgart: Franz Steiner Verlag 2008, ISBN 978-3-515-09161-9, 359 Seiten.

  2. Wildnisbildung als Möglichkeit zur Professionalisierung zukünftiger Geographielehrer/innen – ein neuer Ansatz zur Bildung für nachhaltige Entwicklung?. GW-Unterricht|GW-Unterricht 142/143|

    OpenAIRE

    Lindau, Anne-Kathrin; Hottenroth, Daniela; Lindner, Martin

    2016-01-01

    Der in den deutschen Nationalparken seit mehreren Jahren thematisierte und praktizierte Ansatz der Wildnisbildung stellt möglicherweise einen neuen Zugang zur Bildung für nachhaltige Entwicklung (BNE) in der universitären Lehrer/innenbildung im Fach Geographie dar. Am Beispiel des DBU-geförderten Projektes „Wildnis macht stark“ wird eine Konzeption für die Umsetzung von Wildnisbildung im Rahmen des Geographie-Lehramtsstudiums vorgestellt und mit ersten Forschungsergebnissen zur Wirksamkeit in...

  3. Verfahren zur Hydroformylierung, Liganden mit von Bisphenol A abgeleiteter Struktur und Katalysator umfassend einen Komplex dieser Liganden

    NARCIS (Netherlands)

    2002-01-01

    Die vorliegende Erfindung betrifft ein Verfahren zur Hydroformylierung ethylenisch ungesättigter Verbindungen, wobei man als Hydroformylierungskatalysator wenigstens einen Komplex eines Metalss der VIII. Nebengruppe mit wenigstens einer phosphorhaltigen Verbindung als Liganden einsetzt, wobei diese

  4. Zur linguistischen Beschreibung kommunikativer Einheiten in gesprochener Sprache (On the Linguistic Description of Communicative Units in Oral Language)

    Science.gov (United States)

    Rath, Rainer

    1973-01-01

    Slightly revised version of a lecture ( Zur grammatischen Beschreibung kommunikativer Elemente in Sprechakten'' Y On Grammatical Description of Communicative Elements in Speech''I) presented in Saarbrucken, West Germany, November 10, 1972. (DD)

  5. Robuste Verzweigungserkennung von Gefäßen in CTA-Datensätzen zur modellbasierten Extraktion der Centerline

    Science.gov (United States)

    Beck, Thomas; Fritz, Dominik; Biermann, Christina; Dillmann, Rüdiger

    Bei der Befundung und Visualisierung von Blutgefäßen ist deren Centerline von zentraler Bedeutung. Die Unterscheidung zwischen unverzweigten Abschnitten des Gefäßes und Verzweigungsbereichen ermöglicht den Einsatz spezialisierter und sehr effizienter Algorithmen zur modellbasierten Extraktion der Centerline. In diesem Artikel wird ein robustes Verfahren zur Verzweigungserkennung vorgestellt. Das Verfahren beruht auf einem Front-Propagation-Ansatz mit dynamisch angepassten Schwellwerten und einer anschließenden Clusteranalyse. Die vorgestellte Methode zur Verzweigungserkennung wurde als Komponente einer Architektur zur Extraktion der Centerline auf handannotierten Datensätzen getestet. Erste Ergebnisse sind sehr vielversprechend und ermöglichen auch bei pathologischen Gefäßen eine robuste Detektion von Gefäßverzweigungen.

  6. Auswahl und Verarbeitung von Früchten zur Steigerung der Gehalte an phenolischen Antioxidantien in Fruchtsäften

    OpenAIRE

    Thielen, Christine

    2005-01-01

    Da Polyphenole als gesund angesehen werden, ist es Ziel dieser Arbeit, ihre Gehalte in Fruchtsäften zu erhöhen. Dies beinhaltet zum einen das Auffinden polyphenolreicher Apfel- und Beerenobstsorten als geeignete Rohware. Gleichzeitig entsteht dabei ein Datensatz über sortenreine Apfel- und Beerenobstsäfte, der die RSK-Werte ergänzt. Zum anderen sind Wege zur Minimierung von Verarbeitungsverlusten durch gezielte Studien zur Qualitätssteigerung des Endproduktes Fruchtsaft wichtig. Die im Screen...

  7. Multi-photon absorption limits to heralded single photon sources

    Science.gov (United States)

    Husko, Chad A.; Clark, Alex S.; Collins, Matthew J.; De Rossi, Alfredo; Combrié, Sylvain; Lehoucq, Gaëlle; Rey, Isabella H.; Krauss, Thomas F.; Xiong, Chunle; Eggleton, Benjamin J.

    2013-01-01

    Single photons are of paramount importance to future quantum technologies, including quantum communication and computation. Nonlinear photonic devices using parametric processes offer a straightforward route to generating photons, however additional nonlinear processes may come into play and interfere with these sources. Here we analyse spontaneous four-wave mixing (SFWM) sources in the presence of multi-photon processes. We conduct experiments in silicon and gallium indium phosphide photonic crystal waveguides which display inherently different nonlinear absorption processes, namely two-photon (TPA) and three-photon absorption (ThPA), respectively. We develop a novel model capturing these diverse effects which is in excellent quantitative agreement with measurements of brightness, coincidence-to-accidental ratio (CAR) and second-order correlation function g(2)(0), showing that TPA imposes an intrinsic limit on heralded single photon sources. We build on these observations to devise a new metric, the quantum utility (QMU), enabling further optimisation of single photon sources. PMID:24186400

  8. Non-Poissonian photon statistics from macroscopic photon cutting materials.

    Science.gov (United States)

    de Jong, Mathijs; Meijerink, Andries; Rabouw, Freddy T

    2017-05-24

    In optical materials energy is usually extracted only from the lowest excited state, resulting in fundamental energy-efficiency limits such as the Shockley-Queisser limit for single-junction solar cells. Photon-cutting materials provide a way around such limits by absorbing high-energy photons and 'cutting' them into multiple low-energy excitations that can subsequently be extracted. The occurrence of photon cutting or quantum cutting has been demonstrated in a variety of materials, including semiconductor quantum dots, lanthanides and organic dyes. Here we show that photon cutting results in bunched photon emission on the timescale of the excited-state lifetime, even when observing a macroscopic number of optical centres. Our theoretical derivation matches well with experimental data on NaLaF 4 :Pr 3+ , a material that can cut deep-ultraviolet photons into two visible photons. This signature of photon cutting can be used to identify and characterize new photon-cutting materials unambiguously.

  9. Bacillus licheniformis Contains Two More PerR-Like Proteins in Addition to PerR, Fur, and Zur Orthologues.

    Directory of Open Access Journals (Sweden)

    Jung-Hoon Kim

    Full Text Available The ferric uptake regulator (Fur family proteins include sensors of Fe (Fur, Zn (Zur, and peroxide (PerR. Among Fur family proteins, Fur and Zur are ubiquitous in most prokaryotic organisms, whereas PerR exists mainly in Gram positive bacteria as a functional homologue of OxyR. Gram positive bacteria such as Bacillus subtilis, Listeria monocytogenes and Staphylococcus aureus encode three Fur family proteins: Fur, Zur, and PerR. In this study, we identified five Fur family proteins from B. licheniformis: two novel PerR-like proteins (BL00690 and BL00950 in addition to Fur (BL05249, Zur (BL03703, and PerR (BL00075 homologues. Our data indicate that all of the five B. licheniformis Fur homologues contain a structural Zn2+ site composed of four cysteine residues like many other Fur family proteins. Furthermore, we provide evidence that the PerR-like proteins (BL00690 and BL00950 as well as PerRBL (BL00075, but not FurBL (BL05249 and ZurBL (BL03703, can sense H2O2 by histidine oxidation with different sensitivity. We also show that PerR2 (BL00690 has a PerR-like repressor activity for PerR-regulated genes in vivo. Taken together, our results suggest that B. licheniformis contains three PerR subfamily proteins which can sense H2O2 by histidine oxidation not by cysteine oxidation, in addition to Fur and Zur.

  10. Bacillus licheniformis Contains Two More PerR-Like Proteins in Addition to PerR, Fur, and Zur Orthologues

    Science.gov (United States)

    Ju, Shin-Yeong; Yang, Yoon-Mo; Ryu, Su-Hyun; Kwon, Yumi; Won, Young-Bin; Lee, Yeh-Eun; Youn, Hwan; Lee, Jin-Won

    2016-01-01

    The ferric uptake regulator (Fur) family proteins include sensors of Fe (Fur), Zn (Zur), and peroxide (PerR). Among Fur family proteins, Fur and Zur are ubiquitous in most prokaryotic organisms, whereas PerR exists mainly in Gram positive bacteria as a functional homologue of OxyR. Gram positive bacteria such as Bacillus subtilis, Listeria monocytogenes and Staphylococcus aureus encode three Fur family proteins: Fur, Zur, and PerR. In this study, we identified five Fur family proteins from B. licheniformis: two novel PerR-like proteins (BL00690 and BL00950) in addition to Fur (BL05249), Zur (BL03703), and PerR (BL00075) homologues. Our data indicate that all of the five B. licheniformis Fur homologues contain a structural Zn2+ site composed of four cysteine residues like many other Fur family proteins. Furthermore, we provide evidence that the PerR-like proteins (BL00690 and BL00950) as well as PerRBL (BL00075), but not FurBL (BL05249) and ZurBL (BL03703), can sense H2O2 by histidine oxidation with different sensitivity. We also show that PerR2 (BL00690) has a PerR-like repressor activity for PerR-regulated genes in vivo. Taken together, our results suggest that B. licheniformis contains three PerR subfamily proteins which can sense H2O2 by histidine oxidation not by cysteine oxidation, in addition to Fur and Zur. PMID:27176811

  11. [Philipp Herzog: Sozialistische Völkerfreundschaft nationaler Widerstand oder harmloser Zeitvertieb? Zur politischen Funktion der Volkskunst im sowjetischen Estland] / Karsten Brüggemann

    Index Scriptorium Estoniae

    Brüggemann, Karsten, 1965-

    2014-01-01

    Arvustus: Herzog, Philipp. Sozialistische Völkerfreundschaft, nationaler Widerstand oder harmloser Zeitvertreib? : zur politischen Funktion der Volkskunst im sowjetischen Estland. Stuttgart : Ibidem-Verlag, 2012

  12. CMOS-compatible photonic devices for single-photon generation

    Directory of Open Access Journals (Sweden)

    Xiong Chunle

    2016-09-01

    Full Text Available Sources of single photons are one of the key building blocks for quantum photonic technologies such as quantum secure communication and powerful quantum computing. To bring the proof-of-principle demonstration of these technologies from the laboratory to the real world, complementary metal–oxide–semiconductor (CMOS-compatible photonic chips are highly desirable for photon generation, manipulation, processing and even detection because of their compactness, scalability, robustness, and the potential for integration with electronics. In this paper, we review the development of photonic devices made from materials (e.g., silicon and processes that are compatible with CMOS fabrication facilities for the generation of single photons.

  13. Axion mediated photon to dark photon mixing

    Energy Technology Data Exchange (ETDEWEB)

    Ejlli, Damian [Novosibirsk State University, Department of Physics, Novosibirsk (Russian Federation); Laboratori Nazionali del Gran Sasso, Theory Group, Assergi, L' Aquila (Italy)

    2018-01-15

    The interaction between the dark/mirror sector and the ordinary sector is considered, where the two sectors interact with each other by sharing the same QCD axion field. This feature makes the mixing between ordinary and dark/mirror photons in ordinary and dark electromagnetic fields possible. Perturbative solutions of the equations of motion describing the evolution of fields in ordinary and dark external magnetic fields are found. User-friendly quantities such as transition probability rates and Stokes parameters are derived. Possible astrophysical and cosmological applications of this model are suggested. (orig.)

  14. The irreducible photon

    Science.gov (United States)

    Andrews, David L.

    2009-08-01

    In recent years it has become evident that the primary concept of the photon has multiple interpretations, with widely differing secondary connotations. Despite the all-pervasive nature of this concept in science, some of the ancillary properties with which the photon is attributed in certain areas of application sit uneasily alongside those invoked in other areas. Certainly the range of applications extends far beyond what was envisaged in the original conception, now entering subjects extending from elementary particle physics and cosmology through to spectroscopy, statistical mechanics and photochemistry. Addressing this diverse context invites the question: What is there, that it is possible to assert as incontrovertibly true about the photon? Which properties are non-controversial, if others are the subject of debate? This paper describes an attempt to answer these questions, establishing as far as possible an irreducible core of what can rightly be asserted about the photon, and setting aside some of what often is, but should never be so asserted. Some of the more bewildering difficulties and differences of interpretation owe their origin to careless descriptions, highlighting a need to guard semantic precision; although simplifications are frequently and naturally expedient for didactic purposes, they carry the risk of becoming indelible. Focusing on such issues, the aim is to identify how much or how little about the photon can be regarded as truly non-controversial.

  15. Nonlinear silicon photonics

    Science.gov (United States)

    Tsia, Kevin K.; Jalali, Bahram

    2010-05-01

    An intriguing optical property of silicon is that it exhibits a large third-order optical nonlinearity, with orders-ofmagnitude larger than that of silica glass in the telecommunication band. This allows efficient nonlinear optical interaction at relatively low power levels in a small footprint. Indeed, we have witnessed a stunning progress in harnessing the Raman and Kerr effects in silicon as the mechanisms for enabling chip-scale optical amplification, lasing, and wavelength conversion - functions that until recently were perceived to be beyond the reach of silicon. With all the continuous efforts developing novel techniques, nonlinear silicon photonics is expected to be able to reach even beyond the prior achievements. Instead of providing a comprehensive overview of this field, this manuscript highlights a number of new branches of nonlinear silicon photonics, which have not been fully recognized in the past. In particular, they are two-photon photovoltaic effect, mid-wave infrared (MWIR) silicon photonics, broadband Raman effects, inverse Raman scattering, and periodically-poled silicon (PePSi). These novel effects and techniques could create a new paradigm for silicon photonics and extend its utility beyond the traditionally anticipated applications.

  16. Fuel Effective Photonic Propulsion

    Science.gov (United States)

    Rajalakshmi, N.; Srivarshini, S.

    2017-09-01

    With the entry of miniaturization in electronics and ultra-small light-weight materials, energy efficient propulsion techniques for space travel can soon be possible. We need to go for such high speeds so that the generation’s time long interstellar missions can be done in incredibly short time. Also renewable energy like sunlight, nuclear energy can be used for propulsion instead of fuel. These propulsion techniques are being worked on currently. The recently proposed photon propulsion concepts are reviewed, that utilize momentum of photons generated by sunlight or onboard photon generators, such as blackbody radiation or lasers, powered by nuclear or solar power. With the understanding of nuclear photonic propulsion, in this paper, a rough estimate of nuclear fuel required to achieve the escape velocity of Earth is done. An overview of the IKAROS space mission for interplanetary travel by JAXA, that was successful in demonstrating that photonic propulsion works and also generated additional solar power on board, is provided; which can be used as a case study. An extension of this idea for interstellar travel, termed as ‘Star Shot’, aims to send a nanocraft to an exoplanet in the nearest star system, which could be potentially habitable. A brief overview of the idea is presented.

  17. Photonics for life.

    Science.gov (United States)

    Cubeddu, Rinaldo; Bassi, Andrea; Comelli, Daniela; Cova, Sergio; Farina, Andrea; Ghioni, Massimo; Rech, Ivan; Pifferi, Antonio; Spinelli, Lorenzo; Taroni, Paola; Torricelli, Alessandro; Tosi, Alberto; Valentini, Gianluca; Zappa, Franco

    2011-01-01

    Light is strictly connected with life, and its presence is fundamental for any living environment. Thus, many biological mechanisms are related to light interaction or can be evaluated through processes involving energy exchange with photons. Optics has always been a precious tool to evaluate molecular and cellular mechanisms, but the discovery of lasers opened new pathways of interactions of light with biological matter, pushing an impressive development for both therapeutic and diagnostic applications in biomedicine. The use of light in different fields has become so widespread that the word photonics has been utilized to identify all the applications related to processes where the light is involved. The photonics area covers a wide range of wavelengths spanning from soft X-rays to mid-infrared and includes all devices related to photons as light sources, optical fibers and light guides, detectors, and all the related electronic equipment. The recent use of photons in the field of telecommunications has pushed the technology toward low-cost, compact, and efficient devices, making them available for many other applications, including those related to biology and medicine where these requirements are of particular relevance. Moreover, basic sciences such as physics, chemistry, mathematics, and electronics have recognized the interdisciplinary need of biomedical science and are translating the most advanced researches into these fields. The Politecnico school has pioneered many of them,and this article reviews the state of the art of biomedical research at the Politecnico in the field internationally known as biophotonics.

  18. Antigravity Acts on Photons

    Science.gov (United States)

    Brynjolfsson, Ari

    2002-04-01

    Einstein's general theory of relativity assumes that photons don't change frequency as they move from Sun to Earth. This assumption is correct in classical physics. All experiments proving the general relativity are in the domain of classical physics. This include the tests by Pound et al. of the gravitational redshift of 14.4 keV photons; the rocket experiments by Vessot et al.; the Galileo solar redshift experiments by Krisher et al.; the gravitational deflection of light experiments by Riveros and Vucetich; and delay of echoes of radar signals passing close to Sun as observed by Shapiro et al. Bohr's correspondence principle assures that quantum mechanical theory of general relativity agrees with Einstein's classical theory when frequency and gravitational field gradient approach zero, or when photons cannot interact with the gravitational field. When we treat photons as quantum mechanical particles; we find that gravitational force on photons is reversed (antigravity). This modified theory contradicts the equivalence principle, but is consistent with all experiments. Solar lines and distant stars are redshifted in accordance with author's plasma redshift theory. These changes result in a beautiful consistent cosmology.

  19. Multiple photon resonances

    International Nuclear Information System (INIS)

    Elliott, C.J.; Feldman, B.J.

    1979-02-01

    A detailed theoretical analysis is presented of the interaction of intense near-resonant monochromatic radiation with an N-level anharmonic oscillator. In particular, the phenomenon of multiple photon resonance, the process by which an N-level system resonantly absorbs two or more photons simultaneously, is investigated. Starting from the Schroedinger equation, diagrammatic techniques are developed that allow the resonant process to be analyzed quantitatively, in analogy with well-known two-level coherent phenomena. In addition, multiple photon Stark shifts of the resonances, shifts absent in two-level theory, are obtained from the diagrams. Insights into the nature of multiple photon resonances are gained by comparing the quantum mechanical system with classical coupled pendulums whose equations of motion possess identical eigenvalues and eigenvectors. In certain limiting cases, including that of the resonantly excited N-level harmonic oscillator and that of the equally spaced N-level system with equal matrix elements, analytic results are derived. The influence of population relaxation and phase-disrupting collisions on the multiple photon process are also analyzed, the latter by extension of the diagrammatic technique to the density matrix equations of motion. 11 figures

  20. Subwavelength silicon photonics

    International Nuclear Information System (INIS)

    Cheben, P.; Bock, P.J.; Schmid, J.H.; Lapointe, J.; Janz, S.; Xu, D.-X.; Densmore, A.; Delage, A.; Lamontagne, B.; Florjanczyk, M.; Ma, R.

    2011-01-01

    With the goal of developing photonic components that are compatible with silicon microelectronic integrated circuits, silicon photonics has been the subject of intense research activity. Silicon is an excellent material for confining and manipulating light at the submicrometer scale. Silicon optoelectronic integrated devices have the potential to be miniaturized and mass-produced at affordable cost for many applications, including telecommunications, optical interconnects, medical screening, and biological and chemical sensing. We review recent advances in silicon photonics research at the National Research Council Canada. A new type of optical waveguide is presented, exploiting subwavelength grating (SWG) effect. We demonstrate subwavelength grating waveguides made of silicon, including practical components operating at telecom wavelengths: input couplers, waveguide crossings and spectrometer chips. SWG technique avoids loss and wavelength resonances due to diffraction effects and allows for single-mode operation with direct control of the mode confinement by changing the refractive index of a waveguide core over a range as broad as 1.6 - 3.5 simply by lithographic patterning. The light can be launched to these waveguides with a coupling loss as small as 0.5 dB and with minimal wavelength dependence, using coupling structures similar to that shown in Fig. 1. The subwavelength grating waveguides can cross each other with minimal loss and negligible crosstalk which allows massive photonic circuit connectivity to overcome the limits of electrical interconnects. These results suggest that the SWG waveguides could become key elements for future integrated photonic circuits. (authors)

  1. Reconfigurable topological photonic crystal

    Science.gov (United States)

    Shalaev, Mikhail I.; Desnavi, Sameerah; Walasik, Wiktor; Litchinitser, Natalia M.

    2018-02-01

    Topological insulators are materials that conduct on the surface and insulate in their interior due to non-trivial topology of the band structure. The edge states on the interface between topological (non-trivial) and conventional (trivial) insulators are topologically protected from scattering due to structural defects and disorders. Recently, it was shown that photonic crystals (PCs) can serve as a platform for realizing a scatter-free propagation of light waves. In conventional PCs, imperfections, structural disorders, and surface roughness lead to significant losses. The breakthrough in overcoming these problems is likely to come from the synergy of the topological PCs and silicon-based photonics technology that enables high integration density, lossless propagation, and immunity to fabrication imperfections. For many applications, reconfigurability and capability to control the propagation of these non-trivial photonic edge states is essential. One way to facilitate such dynamic control is to use liquid crystals (LCs), which allow to modify the refractive index with external electric field. Here, we demonstrate dynamic control of topological edge states by modifying the refractive index of a LC background medium. Background index is changed depending on the orientation of a LC, while preserving the topology of the system. This results in a change of the spectral position of the photonic bandgap and the topological edge states. The proposed concept might be implemented using conventional semiconductor technology, and can be used for robust energy transport in integrated photonic devices, all-optical circuity, and optical communication systems.

  2. Models for settlement prediction of structures in opencast dumps; Modelle zur Setzungsprognose von Bauwerken auf Tagebaukippen

    Energy Technology Data Exchange (ETDEWEB)

    Birle, E.; Vogt, S. [Technische Univ. Muenchen (Germany). Zentrum Geotechnik

    2016-05-01

    For construction projects at opencast dumps e.g. for planning of traffic routes or individual buildings a prognosis of dump subsicence after the establishment of the structures is required. It should be noted that on dump surfaces time-dependent subsidence are observed which can change by construction activities at the dump surface. As tools for describing the dump subsidence phenomenological models that have been developed based on the evaluation of dump characteristic subsidence and allow a one-dimensional analysis of creep deformation and visco-elastoplastic material models within the finite element method for analyzing complex geometric boundary conditions. [German] Fuer Baumassnahmen auf Tagebaukippen beispielsweise zur Planung von Verkehrswegen oder einzelnen Bauwerken ist eine Prognose der Kippensetzungen nach Errichtung der Bauwerke erforderlich. Dabei ist zu beachten, dass auf Kippenoberflaechen ausgepraegte zeitabhaengige Setzungen beobachtet werden, die sich durch Baumassnahmen an der Kippenoberflaeche aendern koennen. Als Werkzeuge zur Beschreibung der Kippensetzungen stehen prinzipiell phaenomenologische Modelle, die auf Basis der Auswertung von Kippeneigensetzungen entwickelt wurden und die eine ein-dimensionale Analyse der Kriechverformungen zulassen sowie visko-elastoplastische Stoffmodelle im Rahmen der FiniteElemente- Methode zur Analyse komplexer geometrischer Randbedingungen zur Verfuegung. In Abhaengigkeit vom Randwertproblem ist zu entscheiden, welches der Modelle zur Beschreibung der Kippensetzungen heranzuziehen ist. Mit phaenomenologischen Kriechmodellen und einer ein-dimensionalen Analyse der Verformungen koennen die sich nach Ende der Verkippung einstellenden Kippensetzungen in der Regel genuegend genau beschrieben werden, sofern an der Kippenoberflaeche keine signifikanten Spannungsaenderungen infolge von Baumassnahmen eingetragen werden. Kommt es dagegen zu Spannungsaenderungen, beispielsweise durch die Errichtung eines hohen

  3. Mesoscopic photon heat transistor

    DEFF Research Database (Denmark)

    Ojanen, T.; Jauho, Antti-Pekka

    2008-01-01

    We show that the heat transport between two bodies, mediated by electromagnetic fluctuations, can be controlled with an intermediate quantum circuit-leading to the device concept of a mesoscopic photon heat transistor (MPHT). Our theoretical analysis is based on a novel Meir-Wingreen-Landauer-typ......We show that the heat transport between two bodies, mediated by electromagnetic fluctuations, can be controlled with an intermediate quantum circuit-leading to the device concept of a mesoscopic photon heat transistor (MPHT). Our theoretical analysis is based on a novel Meir......-Wingreen-Landauer-type of conductance formula, which gives the photonic heat current through an arbitrary circuit element coupled to two dissipative reservoirs at finite temperatures. As an illustration we present an exact solution for the case when the intermediate circuit can be described as an electromagnetic resonator. We discuss...

  4. Generation of photon number states

    International Nuclear Information System (INIS)

    Waks, Edo; Diamanti, Eleni; Yamamoto, Yoshihisa

    2006-01-01

    The visible light photon counter (VLPC) has the capability to discriminate photon number states, in contrast to conventional photon counters which can only detect the presence or absence of photons. We use this capability, along with the process of parametric down-conversion, to generate photon number states. We experimentally demonstrate generation of states containing 1, 2, 3 and 4 photons with high fidelity. We then explore the effect the detection efficiency of the VLPC has on the generation rate and fidelity of the created states

  5. Graphene-based photonic crystal

    International Nuclear Information System (INIS)

    Berman, Oleg L.; Boyko, Vladimir S.; Kezerashvili, Roman Ya.; Kolesnikov, Anton A.; Lozovik, Yurii E.

    2010-01-01

    A novel type of photonic crystal formed by embedding a periodic array of constituent stacks of alternating graphene and dielectric discs into a background dielectric medium is proposed. The photonic band structure and transmittance of such photonic crystal are calculated. The graphene-based photonic crystals can be used effectively as the frequency filters and waveguides for the far infrared region of electromagnetic spectrum. Due to substantial suppression of absorption of low-frequency radiation in doped graphene the damping and skin effect in the photonic crystal are also suppressed. The advantages of the graphene-based photonic crystal are discussed.

  6. Update on photon-photon collisions

    International Nuclear Information System (INIS)

    Arteaga-Romero, N.; Cochard, G.; Ong, S.; Amiens Univ., 80; Carimalo, C.; Kessler, P.; Nicolaidis, A.; Parisi, J.; Courau, A.

    1980-03-01

    This report is the continuation of the 'Update' of last year (L.P.C. 79-03, March 1979, in French). In Part I, the structure functions of the photon in QCD are examined. It is shown that, while large psub(T) hadron production is similar to some extent in γγ collisions and in hadron-hadron collisions, the point-like nature of the photon introduces new terms which are entirely calculable, providing new means to test the dynamics of strong interactions. In Part II, problems of analysis in γγ experiments are discussed. The pros and cons of various options with regard to the measurement of outgoing electrons (non-tagging, finite-angle tagging, tagging at 0 0 ) are compared. It is shown that (a) non-tagging may be applied to the study of a limited number of processes only; (b) finite-angle tagging counters allow for various possibilities (double-tagging, single-tagging, double anti-tagging), but none of them is entirely satisfactory; (c) the ideal measurement is double tagging at 0 0 , provided the problem of bremsstrahlung saturation of the tagging counters can be solved

  7. Photon detector for MEGA

    International Nuclear Information System (INIS)

    Gagliardi, C.A.; Tribble, R.E.

    1991-01-01

    During the past year, we have continued work on the photon detector for the MEGA experiment at Los Alamos, a search for the rare decay μ → eγ to a sensitivity of a few parts in 10 13 . The MEGA photon detector is designed to observe the 52.38 MeV photon produced in a μ → eγ decay with an energy resolution of 1.25 MeV, a position resolution of 2 x 5 mm 2 , a directional resolution of 10 degrees, a time resolution of 500 ps, and an efficiency of 7%. It will consists of four independent concentric cylindrical pair spectrometers mounted within a 1.5 T magnetic field produced by a superconducting solenoid magnet. Each pair spectrometer includes two thin Pb foils to convert photons into e + e - pairs, and thereby, determine both their locations and their vector momenta. The inner drift chamber layer includes a delay line cathode to determine the z coordinates needed for track reconstruction. An MWPC located between two Pb layers identifies the conversion layer so that energy loss corrections may be applied, while plastic scintillators provide timing information. Our, group together with a group from the University of Houston, is responsible for the design and construction of the photon detector, as well as developing the computer codes necessary for Monte Carlo simulations and data analysis. During the past year, our efforts have focused primarily on two tasks, delay line cathode read-out and software development. This report describes our recent work on delay lines and data analysis along with a discussion of the new plans for multiplexing in the photon arm

  8. Models for Photon-photon Total Cross-sections

    OpenAIRE

    Godbole, RM; Grau, A; Pancheri, G

    1999-01-01

    We present here a brief overview of recent models describing the photon-photon cross-section into hadrons. We shall show in detail results from the eikonal minijet model, with and without soft gluon summation.

  9. Photonic band gap engineering in 2D photonic crystals

    Indian Academy of Sciences (India)

    Department of Applied Physics, Delhi College of Engineering, Faculty of Technology. (University of ... Photonic crystal; photonic band gap; plane-wave expansion method. PACS Nos 71.20 .... Numerical analysis and results. To obtain the ...

  10. Workplace photon radiation fields

    International Nuclear Information System (INIS)

    Burgess, P.H.; Bartlett, D.T.; Ambrosi, P.

    1999-01-01

    The knowledge of workplace radiation fields is essential for measures in radiation protection. Information about the energy and directional distribution of the incident photon radiation was obtained by several devices developed by the National Radiation Protection Board, United Kingdom, by the Statens Stralskyddsinstitut, Sweden, together with EURADOS and by the Physikalisch-Technische Bundesanstalt, Germany. The devices are described and some results obtained at workplaces in nuclear industry, medicine and science in the photon energy range from 20 keV to 7 MeV are given. (author)

  11. Photon mass experiment

    International Nuclear Information System (INIS)

    Crandall, R.E.

    1983-01-01

    A Coulomb null experiment is described that enables physics students to obtain rigorous upper bounds on photon mass. The experimenter searches for subnanovolt signals that would escape a closed shell were photon mass to be positive. The approach can be adapted for several college levels. At the simplest level, a ''miniature'' low-cost experiment allows a student to verify the exponent ''-2'' in Coulomb's law to eight or more decimal places. An advanced student given a full-size apparatus (at greater cost) can obtain mass bounds very close to the established laboratory limit

  12. Recent developments in the theory of photon-photon collisions

    International Nuclear Information System (INIS)

    Brodsky, S.J.

    1984-09-01

    Over the past few years the field of photon-photon collisions has emerged as one of the best testing grounds for QCD, particularly in the area of exclusive and inclusive hard scattering processes, exotic resonance production, and detailed tests of the coupling of real and virtual photons to the quark current. In this summary of contributed papers, I will briefly review recent theoretical progress in the analysis of two-photon reactions and possible directions for future work. 29 references

  13. QCD measurements in photon-photon collisions at LEP

    OpenAIRE

    Csilling, Akos

    2001-01-01

    An overview of the latest results of the LEP collaborations on QCD measurements in photon-photon collisions is presented, including measurements of the total hadronic cross-section, the production of heavy quarks and dijets and the structure functions of real and virtual photons.

  14. High brightness single photon sources based on photonic wires

    DEFF Research Database (Denmark)

    Claudon, J.; Bleuse, J.; Bazin, M.

    2009-01-01

    We present a novel single-photon-source based on the emission of a semiconductor quantum dot embedded in a single-mode photonic wire. This geometry ensures a very large coupling (> 95%) of the spontaneous emission to the guided mode. Numerical simulations show that a photon collection efficiency...

  15. Tests of perturbative quantum chromodynamics in photon-photon collisions

    International Nuclear Information System (INIS)

    Brodsky, S.J.

    1979-01-01

    The production of hadrons in the collision of two photons via the process e + e - → e + e - X can provide an ideal laboratory for testing many of the features of the photon's hadronic interactions, especially its short-distance aspects. That part of two-photon physics which is particularly relevant to tests of perturbative QCD is reviewed here. 6 figures

  16. Photon sources for absorptiometric measurements

    International Nuclear Information System (INIS)

    Witt, R.M.; Sandrik, J.M.; Cameron, J.R.

    1976-01-01

    Photon absorptiometry is defined and the requirements of photon sources for these measurements are described. Both x-ray tubes and radionuclide sources are discussed, including the advantages of each in absorptiometric systems

  17. The federations' agreement II on network utilisation; Die Verbaendevereinbarung II zur Netznutzung

    Energy Technology Data Exchange (ETDEWEB)

    Birkner, P. [Lech-Elektrizitaetswerke AG, Augsburg (Germany)

    2001-06-18

    Against the background of the experience of the regional supplier Lech Elektrizitaetswerke AG (LEW AG) and in the view of the operator of a regional distribution network the author deals with three complexes of themes: 1. Federations' Agreement II on network utilisation - Flexible instrument for competition or unsuited attempt? 2. What progress and obstacles are identifiable on route towards the implementation of the Federations' Agreement II on network utilisation? 3. What adjustment of existing sets of rules towards the requirements of competition is necessary? (orig.) [German] Vor dem Erfahrungshintergrund des Erfahrungsbereiches des Regionalversorgers Lech-Elektrizitaetswerke AG (LEW AG) und aus der Sicht des Betreibers eines regionalen Verteilungsnetzes behandelt der Verfasser die drei Themenkomplexe: 1. Verbaendevereinbarung II zur Netznutzung - Flexibles Instrument fuer den Wettbewerb oder ungeeigneter Versuch? 2. Welche Fortschritte und Hindernisse sind auf dem Wege der Umsetzung der Verbaendevereinbarung II zur Netznutzung erkennbar? 3. Welche Anpassung vorhandener Regelwerke an die Erfordernisse des Wettbewerbs sind notwendig? (orig.)

  18. Anleitung zur Gründung und Pflege von Online-Netzwerken

    Directory of Open Access Journals (Sweden)

    Nicola Döring

    2006-11-01

    Full Text Available Internet-Nutzung ist in der weiblichen Bevölkerung geringer verbreitet als in der männlichen (Internet Gender Gap. Hinzu kommen geschlechtsspezifische Unterschiede in Umfang und Art der Internet-Aneignung (Gendered Digital Inequalities. Eine Reihe von Initiativen bemüht sich darum, Mädchen und Frauen den Internet-Zugang zu erleichtern und ihre Internet-Kompetenz zu steigern (z. B. www.frauen-ans-netz.de. Der vorliegende Praxisleitfaden geht einen Schritt weiter und möchte nicht nur zur Internet-Nutzung, sondern zur aktiven Internet-Gestaltung anregen im Sinne der Gründung neuer virtueller Mädchen- und Frauennetzwerke. Technologische, ökonomische, soziale, psychologische und geschlechterpolitische Aspekte dieser Netzwerke werden behandelt und an Beispielen illustriert.

  19. ALICE Photon Spectrometer

    CERN Multimedia

    Kharlov, Y

    2013-01-01

    PHOS provides unique coverage of the following physics topics: - Study initial phase of the collision of heavy nuclei via direct photons, - Jet-quenching as a probe of deconfinement, studied via high Pτ ϒ and π0, - Signals of chiral-symmetry restoration, - QCD studies in pp collisions via identified neutral spectra.

  20. Photon strength functions

    International Nuclear Information System (INIS)

    Bergqvist, I.

    1976-01-01

    Methods for extracting photon strength functions are briefly discussed. We follow the Brink-Axel approach to relate the strength functions to the giant resonances observed in photonuclear work and summarize the available data on the E1, E2 and M1 resonances. Some experimental and theoretical problems are outlined. (author)

  1. Direct photon experiments

    International Nuclear Information System (INIS)

    Boeggild, H.

    1986-11-01

    The author reviews the experiments on direct photon production in hadronic collisions. After a description of the experimental methods for the study of such processes he presents some results on differential cross sections and the γ/π 0 ratio in π - p, π + p, pp, and anti pp processes as well as in reactions of π - , π + , and p on carbon. (HSI)

  2. Total photon absorption

    International Nuclear Information System (INIS)

    Carlos, P.

    1985-01-01

    Experimental methods using real photon beams for measurements of total photonuclear absorption cross section σ(Tot : E/sub γ/) are recalled. Most recent σ(Tot : E/sub γ/)results for complex nuclei and in the nucleon resonance region are presented

  3. Magnetic photon scattering

    International Nuclear Information System (INIS)

    Lovesey, S.W.

    1987-05-01

    The report reviews, at an introductory level, the theory of photon scattering from condensed matter. Magnetic scattering, which arises from first-order relativistic corrections to the Thomson scattering amplitude, is treated in detail and related to the corresponding interaction in the magnetic neutron diffraction amplitude. (author)

  4. Photon collider at TESLA

    International Nuclear Information System (INIS)

    Telnov, Valery

    2001-01-01

    High energy photon colliders (γγ, γe) based on backward Compton scattering of laser light is a very natural addition to e + e - linear colliders. In this report, we consider this option for the TESLA project. Recent study has shown that the horizontal emittance in the TESLA damping ring can be further decreased by a factor of four. In this case, the γγ luminosity in the high energy part of spectrum can reach about (1/3)L e + e - . Typical cross-sections of interesting processes in γγ collisions are higher than those in e + e - collisions by about one order of magnitude, so the number of events in γγ collisions will be more than that in e + e - collisions. Photon colliders can, certainly, give additional information and they are the best for the study of many phenomena. The main question is now the technical feasibility. The key new element in photon colliders is a very powerful laser system. An external optical cavity is a promising approach for the TESLA project. A free electron laser is another option. However, a more straightforward solution is ''an optical storage ring (optical trap)'' with a diode pumped solid state laser injector which is today technically feasible. This paper briefly reviews the status of a photon collider based on the linear collider TESLA, its possible parameters and existing problems

  5. What is a Photon?

    Indian Academy of Sciences (India)

    IAS Admin

    we say we `see' something, what we are talking about is that some photons ... Nobel Prize for his work in QED, and called it the strange theory of light and matter. Strange .... its form was assumed by him in order to get the correct expression for ...

  6. Jet production in photon-photon interactions

    International Nuclear Information System (INIS)

    Berger, C.; Genzel, H.; Lackas, W.; Pielorz, J.; Raupach, F.; Wagner, W.; Buerger, J.; Criegee, L.; Deuter, A.; Franke, G.; Gerke, C.; Knies, G.; Lewendel, B.; Meyer, J.; Michelsen, U.; Pape, K.H.; Timm, U.; Winter, G.G.; Zimmermann, W.; Zachara, M.; Ferrarotto, F.; Gaspero, M.; Stella, B.; Bussey, P.J.; Cartwright, S.L.; Dainton, J.B.; Hendry, D.; King, B.T.; Raine, C.; Scarr, J.M.; Skillicorn, I.O.; Smith, K.M.; Thomson, J.C.; Achterberg, O.; Blobel, V.; Burkart, D.; Diehlmann, K.; Feindt, M.; Kapitza, H.; Koppitz, B.; Krueger, M.; Poppe, M.; Spitzer, H.; Staa, R. van; Almeida, F.; Baecker, A.; Barreiro, F.; Brandt, S.; Derikum, K.; Grupen, C.; Meyer, H.J.; Mueller, H.; Neumann, B.; Rost, M.; Stupperich, K.; Zech, G.; Alexander, G.; Bella, G.; Gnat, Y.; Grunhaus, J.; Junge, H.; Kraski, K.; Maxeiner, C.; Maxeiner, H.; Meyer, H.; Schmidt, D.

    1987-01-01

    We present results on jet production in γγ interactions where both photons are quasi-real. The invariant masses of the hadronic system are limited to the range 4≤W vis 12 GeV/c 2 . The data approach the Quark-Parton-Model (QPM) expectation at the highest p T jet values (≥4 GeV/c). Jet production at low p T (≤1 GeV/c) can be described by a Vector Dominance derived model. The data also have a component with no apparent jet structure in the range, 1.0≤p T jet ≤4.0 GeV/c which can be described by phase space or by models of the QCD hard scattering processes γγ→qanti qg and γγ→qanti qqanti q. (orig.)

  7. Limits on the photon mass

    International Nuclear Information System (INIS)

    Vasseur, G.

    1996-03-01

    Is the photon mass strictly null as it is told in quantum electrodynamics. In fact, a coherent theory can be build with a massive photon. Experiences have been regularly led to try to make obvious an eventual non null photon mass. Superior limits more and more strict have been found. Here is given a general survey of the consequences of a non null photon mass, different methods to measure it and the achieved limits. (author). 30 refs., 1 fig

  8. Biomedical photonics handbook biomedical diagnostics

    CERN Document Server

    Vo-Dinh, Tuan

    2014-01-01

    Shaped by Quantum Theory, Technology, and the Genomics RevolutionThe integration of photonics, electronics, biomaterials, and nanotechnology holds great promise for the future of medicine. This topic has recently experienced an explosive growth due to the noninvasive or minimally invasive nature and the cost-effectiveness of photonic modalities in medical diagnostics and therapy. The second edition of the Biomedical Photonics Handbook presents fundamental developments as well as important applications of biomedical photonics of interest to scientists, engineers, manufacturers, teachers, studen

  9. Photons, photon jets, and dark photons at 750 GeV and beyond.

    Science.gov (United States)

    Dasgupta, Basudeb; Kopp, Joachim; Schwaller, Pedro

    2016-01-01

    In new physics searches involving photons at the LHC, one challenge is to distinguish scenarios with isolated photons from models leading to "photon jets". For instance, in the context of the 750 GeV diphoton excess, it was pointed out that a true diphoton resonance [Formula: see text] can be mimicked by a process of the form [Formula: see text], where S is a new scalar with a mass of 750 GeV and a is a light pseudoscalar decaying to two collinear photons. Photon jets can be distinguished from isolated photons by exploiting the fact that a large fraction of photons convert to an [Formula: see text] pair inside the inner detector. In this note, we quantify this discrimination power, and we study how the sensitivity of future searches differs for photon jets compared to isolated photons. We also investigate how our results depend on the lifetime of the particle(s) decaying to the photon jet. Finally, we discuss the extension to [Formula: see text], where there are no photons at all but the dark photon [Formula: see text] decays to [Formula: see text] pairs. Our results will be useful in future studies of the putative 750 GeV signal, but also more generally in any new physics search involving hard photons.

  10. Photons, photon jets and dark photons at 750 GeV and beyond

    International Nuclear Information System (INIS)

    Dasgupta, Basudeb; Kopp, Joachim

    2016-03-01

    In new physics searches involving photons at the LHC, one challenge is to distinguish scenarios with isolated photons from models leading to ''photon jets''. For instance, in the context of the 750 GeV diphoton excess, it was pointed out that a true diphoton resonance S → γγ can be mimicked by a process of the form pp → S → aa → 4γ, where S is a new scalar with a mass of 750 GeV and a is a light pseudoscalar decaying to two collinear photons. Photon jets can be distinguished from isolated photons by exploiting the fact that a large fraction of photons convert to an e + e - pair inside the inner detector. In this note, we quantify this discrimination power, and we study how the sensitivity of future searches differs for photon jets compared to isolated photons. We also investigate how our results depend on the lifetime of the particle(s) decaying to the photon jet. Finally, we discuss the extension to S → A'A' → e + e - e + e - , where there are no photons at all but the dark photon A' decays to e + e - pairs. Our results will be useful in future studies of the putative 750 GeV signal, but also more generally in any new physics search involving hard photons.

  11. Vom Fachwissen zur Handlungskompetenz - die Berufsschule vor den Herausforderungen des sozioökonomischen Strukturwandels

    OpenAIRE

    Kouli, Ekaterina

    2006-01-01

    Der sozioökonomische Wandel und die damit einhergehenden Veränderungen der Wirtschafts- und Beschäftigungsstrukturen stellen das Bildungssystem in Deutschland vor neuartige Herausforderungen. Wesentliche Momente dieses Wandels sind die technologische Entwicklung, die Globalisierung der Wirtschaft, der Übergang von der Industrie- zur Wissensgesellschaft sowie Veränderungen in den gesellschaftlichen Wertvorstellungen. Diese Entwicklungen verändern die Arbeitsprozesse in den Unternehmen und dami...

  12. Ausbau der ganztägigen Kindertagesbetreuung kann zur Zufriedenheit von Müttern beitragen

    OpenAIRE

    Stahl, Juliane F.; Schober, Pia S.

    2016-01-01

    Eltern mit Kindern, die noch nicht zur Schule gehen, stehen bei der Vereinbarkeit von Familie und Beruf vor besonderen Herausforderungen. Um diese Eltern besser zu unterstützen, hat die Politik sowohl den Ausbau von Plätzen in der öffentlichen Kindertagesbetreuung (Kita) forciert als auch ein bedarfsorientiertes Angebot an Ganztagsplätzen gesetzlich verankert. Der vorliegende Beitrag untersucht auf Basis von Daten des Sozio-oekonomischen Panels (SOEP) und der Stichprobe 'Familien in Deutschla...

  13. Beiträge zur Beugungstheorie elektromagnetischer Wellen an Kanten vollkommen leitender Flächen

    OpenAIRE

    Zinal, Sherko

    2011-01-01

    Den Kern der vorliegenden Arbeit bilden die Untersuchung sowie die Formulierung von Lösungsansätzen für ein elementares, elektromagnetisches Beugungsproblem; einer undendlich langen Schlitzleitung mit einseitig begrenzter etallisierungsplatte (Abschnitt 1.2). Motiviert wird dieses Beugungsproblem im Hinblick auf die Beugungsproblematik planarer Strahler (Antennen) mit endlich ausgedehnter Grundmetallisierung (Abschnitt 1.1). In Kapitel 2 wird ein Stromlinien-Modell zur Formulierung des Beugun...

  14. Ein praxisorientierter empirischer Ansatz zur Bestimmung des Ausfallverhaltens konventioneller Bremssysteme in Personenkraftwagen

    OpenAIRE

    Althaus, Dirk

    2009-01-01

    Der Funktionsumfang im Kraftfahrzeug nimmt bekanntlich stetig zu. Neben vollständig neu entwickelten Systemen werden aber auch bestehende durch zusätzliche Funktionen erweitert. Besonders für Sicherheitssysteme kann dies weitreichende Folgen haben, da solche Mehrbelastungen nicht nur zur Minderung der Zuverlässigkeit beitragen können, sondern evtl. auch die Sicherheit herabsetzen. Durch die steigende Vernetzung der Systeme und Komponenten untereinander ist es darüber hinaus nicht mehr aus...

  15. Aufbau humaner 3D-in-vitro-Testsysteme zur Risikobewertung von Nanomaterialien

    OpenAIRE

    Hampel, Martina

    2009-01-01

    Die Nanotechnologie stellt eine der Schlüsseltechnologien dieses Jahrhunderts dar Parallel zur Erschließung neuer Möglichkeiten, die die Nanotechnologie bietet, müssen jedoch auch mögliche Risiken untersucht werden. Die dabei zurzeit noch am häufigsten eingesetzte Untersuchungsmethode von Nanopartikeln ist die Verwendung zweidimensionaler in vitro Zellkulturen. Zum Einsatz kommen hier jedoch meist Zelllinien. Die Versuchsansätze entsprechen damit nicht den Bedingungen im menschlichen Körper. ...

  16. Ergebnisse einer empirischen Untersuchung zur Klangfarbenwahmehmung von Vorschulkindern mit einem Klangmemory

    OpenAIRE

    Schellberg, Gabriele

    1998-01-01

    Im Unterschied zu anderen Bereichen der musikalischen Wahrnehmung gibt es zur Klangfarbenwahmehmung nur wenige Untersuchungen. Ein Grund dafür dürfte in den methodischen Schwierigkeiten liegen, die insbesondere bei der Untersuchung kleiner Kinder auftreten. Ein Klangfarbentest für Vorschulkinder existiert bislang nicht. Daher wurde nach mehreren Voruntersuchungen ein „Klangfarben-Memory“ als Methode entwickelt und bei Vorschulkindern eingesetzt. Die Ergebnisse dieser empirischen Studie werden...

  17. Implementierung, Evaluation und vergleichende Untersuchungen des Powerplex 16 Systems zur quantitativen Chimärismusanalyse

    OpenAIRE

    Joachim, Stefanie

    2010-01-01

    Die allogene Stammzelltransplantation ist ein Verfahren zur Therapie verschiedener maligner und nicht-maligner hämatologischer Erkrankungen. Da es sich um eine sehr aufwendige Therapie handelt, sind Methoden, die den Behandlungsverlauf dokumentieren, wie minimale Resterkrankung und Chimärismusanalyse, essentiell. Eine nach Stammzelltransplantation vollständig vom Spender abgeleitete Hämatopoese ist Voraussetzung für das Engraftment und die Prophylaxe eines Rezidivs der zugrundeliegenden Er...

  18. Isolation und Charakterisierung retroviraler Partikel und Proteine zur Untersuchung immunsuppressiver Effekte

    OpenAIRE

    Pietsch, Heiko

    2016-01-01

    Obgleich auf dem Gebiet der Transplantationsmedizin in jüngster Zeit beachtliche Fortschritte erzielt worden sind, ist der Mangel an Organspendern ein fortbestehendes Problem. Im Rahmen der Xenotransplantation können Schweine als Spender zur Transplantation von Zellen oder Organen beim Menschen dienen. Um die Sicherheit der Xenotransplantation zu gewährleisten, ist sowohl die Entwicklung sensitiver Nachweismethoden als auch die Einschätzung des Gefahrenpotentials durch eine Infektion für den ...

  19. Sprache als Schlüssel zur Welt: Bibliotheken und Sprach-Kitas in guter Partnerschaft

    OpenAIRE

    Susanne Brandt

    2017-01-01

    Von 2016 bis voraussichtlich 2020 wird durch das Bundesministerium für Familie, Senioren, Frauen und Jugend das Bundesprogramm „Sprach-Kitas. Weil Sprache der Schlüssel zur Welt ist“ gefördert. Es richtet sich an Kindertageseinrichtungen, die von einem überdurchschnittlich hohen Anteil von Kindern mit besonderem Bedarf an sprachlicher Bildung und Förderung besucht werden. Dabei stehen besonders die folgenden drei Zielbereiche im Fokus: alltagsintegrierte sprachliche Bildung, inklusive Bildung...

  20. Erstellung einer Checkliste zur Beurteilung des Arbeitsplatzes eines Physiotherapeuten nach ergonomischen Gesichtspunkten

    OpenAIRE

    Gauermann, Christoph

    2013-01-01

    Einleitung: Arbeitsbedingte Erkrankungen des Muskel-Skelett-Systems sind unter Physiotherapeuten sehr häufig. Die präventive Forschung hat diese Berufsgruppe bisher kaum untersucht. In diesem Zusammenhang stellt die Veränderung des Arbeitsumfeldes einen vielversprechenden Ansatz für die Verhinderung arbeitsbedingter Erkrankungen dar. Das Ziel dieser Arbeit ist die Erstellung einer Checkliste zur Bewertung des Arbeitsplatzes eines Physiotherapeuten zu erstellen. Material und Methoden: ...

  1. Entwicklung und Anwendung von Methoden zur Bestimmung von Selen-Spezies in human-biologischem Material

    OpenAIRE

    Jäger, Thomas

    2014-01-01

    Selen ist essentieller Bestandteil von mehr als 25 physiologisch wichtigen menschlichen Enzymen. Der tägliche Bedarf wird überwiegend in Form von organischen Selenverbindungen wie Selenmethionin oder Selenocystein aus der Nahrung aufgenommen. Weitere Expositionswege sind die Einnahme von Nahrungsergänzungsmitteln zur Selensupplementation sowie die inhalative oder dermale Aufnahme von in erster Linie anorganischen Selenverbindungen oder elementarem Selen an Arbeitsplätzen der Selen-verarbeiten...

  2. Bildgebendes Multispektralsystem zur Serienfarbmessung an goniochromatischen Oberflächenbeschichtungen in der Automobil- und Zulieferindustrie

    OpenAIRE

    Jäger, Stefan

    2006-01-01

    In dieser Arbeit wird ein multispektrales bildgebendes System zur Farbmessung von Metall- und Perleffektlacken in einem industriellen Umfeld vorgestellt. Der Zweck des vorgeschlagenen Systems ist die Serienüberwachung und daraus folgend, die Steuerung von Lackierprozessen in der Automobil- und Zulieferindustrie, um das Qualitätsniveau anzuheben und Kosten zu reduzieren. Ausgehend von der Analyse der messtechnischen Anforderungen und den durch die Prozesstechnik gegebenen Randbedingungen wurde...

  3. New facade concepts ranging from statics to dynamics; Neue Fassadenkonzepte. Von der Statik zur Dynamik

    Energy Technology Data Exchange (ETDEWEB)

    Kranz, H.R. [Siemens AG, Karlsruhe (Germany)

    1995-12-31

    In chapter 9 of the anthology about building control new facade concepts are presented, including new facade technologies, conductivity of new facade concepts and combination of new technologies. The whole complex ranging from statics to dynamics is explained. (BWI) [Deutsch] Kapitel 9 des Sammelbandes ueber Building Control stellt neue Fassadenkonzepte vor: Neue Fassadentechnologien, Leitfunktionen neuer Fassadenkonzepte, Kombination neuer Technologien. In diesem Zusammenhang wird der gesamte Komplex von der Statik bis zur Dynamik behandelt. (BWI)

  4. Entwicklung von Cysteinproteaseinhibitoren - ein klassischer und ein kombinatorischer Ansatz zur Inhibitoroptimierung

    OpenAIRE

    Machon, Uwe Rainer

    2009-01-01

    Ziel der Dissertation „Entwicklung von Cysteinproteaseinhibitoren – ein klassischer und ein kombinatorischer Ansatz zur Inhibitoroptimierung“ war die Optimierung von neuen Inhibitoren von Falcipain-2 und Rhodesain als neue potentielle Wirkstoffe gegen Malaria bzw. die Schlafkrankheit über zwei verschiedene Methoden. Es handelt sich hierbei um einen klassischen und einen kombinatorischen Ansatz. Der klassische Ansatz basiert auf einer Struktur, deren Aktivität per Zufall entdeckt wurde. In Scr...

  5. Multi-photon entanglements

    International Nuclear Information System (INIS)

    Daniell, M.L.

    2000-09-01

    The motivation of this thesis was to create higher-order entanglements. The first experimental observation of a four-photon entanglement was presented in the experiment of this thesis. And the visibility of this entanglement was 0.79+-0.06, which is sufficient to make claims of the nonlocality of quantum mechanics. This therefore lays a foundation for experiments showing the nonlocality of teleportation, and the purification of entanglement. The work of this thesis brings together a lot of earlier work done by the Zeilinger Group, and lays a foundation for future experiments. Earlier experiments such as teleportation together with entanglement swapping, which are 'complete teleportation' in as much as the state teleported is entirely undefined, can be combined and re-done with this four-photon entanglement. This result would be the first demonstration of complete, nonlocal teleportation. Also this experiment can be slightly modified and used to perform the first experimental quantum purification of entanglement, which is of vital importance to the fields of quantum information, and also is interesting for fundamental experiments on entanglement. Another direct application of this experiment is to perform the first 'event-ready' testing of Bell's Inequality. Here the four-photon entanglement can be used as a source of entangled photons, whereby the photons have no common source. This would enable an even more stringent testing of Bells theorem. Finally this experiment can be used for the demonstration and investigation of many practical, directly applicable quantum information schemes. For instance quantum cryptography, error correction, and computing. (author)

  6. Nonlinear photonic quasicrystals

    International Nuclear Information System (INIS)

    Freedman, B.; Bartal, G.; Segev, M.; Lifshitz, R.; Christodoulides, D.; Fleischer, J.

    2005-01-01

    Full Text:Quasicrystals are structures with long-range order and no periodicity, whose unique structural and physical properties have intrigued scientists ever since their discovery and initial theoretical analysis more than two decades ago. The lack of periodicity excludes the use of well-established theoretical and experimental tools for the analysis of quasicrystals, including such notions as the Brillouin zone and Bloch theorem. Instead, the quasiperiodic atomic arrangement gives rise to unique properties such as a hierarchy of effective Brillouin (or Jones) zones, yielding a fractal-like band structure, and the existence of unique phason degrees of freedom. Generally, in atomic quasicrystals it is very difficult to directly observe the evolution of electronic wave-packets propagating through the structure, or the dynamics of the structure itself. Photonic quasicrystals, on the other hand, are macroscopic objects and hence their internal wave dynamics can be locally excited and directly imaged. Here, we employ optical induction to create 2D photonic quasicrystals, and explore wave transport phenomena in quasicrystals in ways that were impossible until now. We demonstrate linear tunneling-transport of light initiated at different crystal sites, and observe the formation of lattice solitons when the light is made sufficiently intense. We experiment with dynamical photonic quasicrystals, in which crystal sites interact with one another, and directly observe dislocation dynamics: creation, healing, and local structural rearrangement due to phason flips. Our experiments show that photonic quasicrystals are an excellent model system through which one can study the universal features of wave dynamics in quasiperiodic structures, that should apply not only to photonics, but also to other systems such as matter waves in quasiperiodic traps, generic pattern-forming systems as in parametrically-excited surface waves, liquid quasicrystals, as well as the more familiar

  7. The three-photon vertex

    International Nuclear Information System (INIS)

    Delbourgo, R.

    1976-01-01

    Owing to weak interactions, the three-photon vertex is non-zero. From gauge invariance and symmetry requirements, it is proved that the C = -1P = - 1 vertex amplitudes are at least of order q 7 in the limit of soft photon momentum q and that if any two photons are placed on mass shell the form factors vanish identically. (author)

  8. Optimization of photonic crystal cavities

    DEFF Research Database (Denmark)

    Wang, Fengwen; Sigmund, Ole

    2017-01-01

    We present optimization of photonic crystal cavities. The optimization problem is formulated to maximize the Purcell factor of a photonic crystal cavity. Both topology optimization and air-hole-based shape optimization are utilized for the design process. Numerical results demonstrate...... that the Purcell factor of the photonic crystal cavity can be significantly improved through optimization....

  9. Konkurrenz oder Kooperation? Zur Entwicklung des Verhältnisses von Medienbildung und informatischer Bildung

    Directory of Open Access Journals (Sweden)

    Gerhard Tulodziecki

    2016-10-01

    Full Text Available Mit der gegenwärtigen Diskussion um Mediatisierung und Digitalisierung ist die Forderung verbunden, der Medienbildung und/oder der informatischen Bildung ein größeres Gewicht in der schulischen Bildung zu verschaffen. Dies legt die Frage nahe, wie ein produktives Verhältnis zwischen beiden gestaltet werden sollte und wie beide am besten zu einer zeitgemäßen Bildung beitragen können. Bei entsprechenden Überlegungen spielen unter anderem Entwicklungen eine Rolle, die sich seit frühen Forderungen nach einer Computerbildung im Verhältnis zur damaligen Medienerziehung herausgebildet haben. In dem vorliegenden Beitrag werden solche Entwicklungen skizziert und Schlussfolgerungen für die gegenwärtige Diskussion formuliert. Dabei kommen unterschiedliche Auffassungen zur bildungsbezogenen Auseinandersetzung mit Medien sowie mit Informations- und Kommunikationstechnologien in den Blick. Für das Verhältnis von Medienbildung und informatischer Bildung ergibt sich als zentrale Schlussfolgerung, dass sowohl eine Integration der informatischen Bildung in die Medienbildung als auch eine umgekehrte Lösung unangemessen erscheint, wiewohl beide Bereiche auf Anteile aus dem jeweils anderen Bereich angewiesen sind. Danach werden für eine Medienbildung mit informatischen Anteilen ein geeigneter Medienbegriff und eine tragfähige Bildungsauffassung sowie ein Ansatz zu einem inhaltlich-thematischen Kompetenzrahmen beschrieben. Überlegungen zur schulischen Umsetzung schließen den Beitrag ab.

  10. Neuere Untersuchungen zur Prädiktion von EEG-Signalen bei Epilepsie

    Directory of Open Access Journals (Sweden)

    C. Niederhöfer

    2007-06-01

    Full Text Available Seit einigen Jahren ist die Analyse von EEG-Signalen bei Epilepsie Gegenstand zahlreicher wissenschaftlicher Arbeiten; Zielvorstellung ist dabei die Entwicklung von Verfahren zur Erkennung eines möglichen Voranfallszustandes. Im Vordergrund steht beispielsweise die Approximation einer so genannten effektiven Korrelationsdimension, die Bestimmung der maximalen Lyapunov-Exponenten, Detektionsverfahren für Muster bei Zellularen Nichtlinearen Netzwerken, die Bestimmung der mittleren Phasenkohärenz und Verfahren zur nichtlinearen Prädiktion von EEG-Signalen. Trotz umfangreicher Bemühungen kann bis heute eine Erkennung von Anfallsvorboten mit einer Sensitivität und Spezifität, die eine automatisierte Anfallsvorhersage ermöglichen würde, noch nicht durchgeführt werden. In diesem Beitrag werden neue Ergebnisse zur Prädiktion von EEG-Signalen bei Epilepsie vorgestellt. Dabei werden Signale, welche mittels intrakranieller electrocorticographischer (ECoG und stereoelectroencephalographischer (SEEG Ableitungen registriert wurden, segmentweise analysiert. Unter der Annahme, dass sich Änderungen des Systems ,,Gehirn" als Änderungen im Prädiktor, d.h. in seinen Systemparametern widerspiegeln, könnte eine nähere Betrachtung der Prädiktoreigenschaften zu einer Erkennung von Anfallsvorboten führen.

  11. The Density Matrix for Single-mode Light after k-Photon Absorption

    Science.gov (United States)

    Voigt, H.; Bandilla, A.

    In order to continue and generalize the studies of the density matrix of a light field undergoing k-photon absorption, in this paper we put the emphasis on the off-diagonal elements. The solution obtained earlier for the diagonal elements describing the photon statistics can be found as a special case but will not be discussed again. The general solution calculated by recursion shows an asymptotic behaviour if the initial photon number is sufficiently high. Only the initial phase information survives. Illustrating the solution we start with coherent light and a generalized coherent state.Translated AbstractDie Dichtematrix eines Lichtstrahls nach k-Photonen-Absorption aus einer ModeWir führen die Betrachtungen über das Verhalten der Dichtematrix eines Lichtfeldes nach k-Photonen-Absorption aus einer Mode verallgemeinernd weiter und konzentrieren uns auf die Nichtdiagonalelemente. Die im folgenden angegebene allgemeine Lösung, die durch Rekursion gefunden wurde, enthält die schon früher erhaltene, jedoch hier nicht weiter diskutierte Lösung für die Diagonalelemente als Spezialfall. Sie zeigt ferner, daß es einen asymptotischen Zustand gibt, der eine von der Ausgangsintensität unabhängige Information über die Ausgangsphase enthält. Zur Diskussion der Lösung werden verschiedene Anfangsbedingungen betrachtet, so z. B. kohärentes Licht und kohärentes Licht, das ein Medium mit nichtlinearem Brechungsindex durchlaufen hat (Kerr-Effekt).

  12. Neuromorphic photonic networks using silicon photonic weight banks.

    Science.gov (United States)

    Tait, Alexander N; de Lima, Thomas Ferreira; Zhou, Ellen; Wu, Allie X; Nahmias, Mitchell A; Shastri, Bhavin J; Prucnal, Paul R

    2017-08-07

    Photonic systems for high-performance information processing have attracted renewed interest. Neuromorphic silicon photonics has the potential to integrate processing functions that vastly exceed the capabilities of electronics. We report first observations of a recurrent silicon photonic neural network, in which connections are configured by microring weight banks. A mathematical isomorphism between the silicon photonic circuit and a continuous neural network model is demonstrated through dynamical bifurcation analysis. Exploiting this isomorphism, a simulated 24-node silicon photonic neural network is programmed using "neural compiler" to solve a differential system emulation task. A 294-fold acceleration against a conventional benchmark is predicted. We also propose and derive power consumption analysis for modulator-class neurons that, as opposed to laser-class neurons, are compatible with silicon photonic platforms. At increased scale, Neuromorphic silicon photonics could access new regimes of ultrafast information processing for radio, control, and scientific computing.

  13. Photorefractive Photonics 2017

    International Nuclear Information System (INIS)

    2017-01-01

    Preface This volume of Journal of Physics: Conference Series represents a selection of the contributions presented in the Photorefractive Photonics 2017 (PR17) conference which was held in Qingdao, Shandong, China from July 17 through July 20, 2017. The conference is the successor of the traditional Photorefractive (PR) Conference Series: the International Conference on Photorefractive Effects, Materials and Devices. The first PR Conference was held in Los Angeles, California, USA in 1987. After that, the PR Conference was held every two years around the world: Aussois, France (1989), Beverly, Massachusetts, USA (1991), Kiev, Ukraine (1993), Aspen Lodge, Colorado, USA (1995), Chiba, Japan (1997), Elsinore, Denmark (1999), Delevan, Wisconsin, USA (2001), Nice, France (2003), Sanya, Hainan, China (2005), Olympic Valley, California, USA (2007), Bad Honnef, Germany (2009), Ensenada, Mexico (2011), Winchester, UK (2013) and Villars, Switzerland (2015). The Conference was renamed to be Photorefractive Photonics Conference in 2015. The PR17 conference was organized by Nankai University, Qingdao University and Qingdao Society of Physics. The scientific topics of the PR17 conference include, but not limited to, wave mixing and its applications (T1), nonlinear light-matter interaction and its applications (T2), material engineering and photonic micro-structures (T3), photorefractive lattice photonics (T4), digital photorefractive photonics (T5), and novel photorefractive effects, materials and applications (T6). Note that both traditional topics such as photorefractive wave mixing and new topics such as energy photonics and nano/micro-structures based on photorefractive effects and materials are included, especially, basic issues such as the influence of pyroelectric effect on the photorefractive wave-mixing are considered, and much attention was paid to the development of new applications of photorefractive effects and materials, which reflect the current state of the art

  14. Physics with Photons in ATLAS

    CERN Multimedia

    CERN. Geneva

    2011-01-01

    The fine granularity ATLAS electromagnetic calorimeter provides a precise measurement of the photon energy and direction, as well as efficient rejection of background from fake photons, while the high precision inner detector allows also the reconstruction of photons that convert into electron-positron pairs.Isolated photons are measured using well-defined infrared-safe isolation criteria corrected for underlying event and the effects of additional proton-proton collisions. Differential cross sections for inclusive photons and diphotons are presented, and the spectrum of diphoton production is used to search for the Higgs boson in this decay channel.

  15. Few-photon optical diode

    OpenAIRE

    Roy, Dibyendu

    2010-01-01

    We propose a novel scheme of realizing an optical diode at the few-photon level. The system consists of a one-dimensional waveguide coupled asymmetrically to a two-level system. The two or multi-photon transport in this system is strongly correlated. We derive exactly the single and two-photon current and show that the two-photon current is asymmetric for the asymmetric coupling. Thus the system serves as an optical diode which allows transmission of photons in one direction much more efficie...

  16. Photon + jets at D0

    Energy Technology Data Exchange (ETDEWEB)

    Sonnenschein, Lars; /RWTH Aachen U.

    2009-06-01

    Photon plus jet production has been studied by the D0 experiment in Run II of the Fermilab Tevatron Collider at a centre of mass energy of {radical}s = 1.96 TeV. Measurements of the inclusive photon, inclusive photon plus jet, photon plus heavy flavour jet cross sections and double parton interactions in photon plus three jet events are presented. They are based on integrated luminosities between 0.4 fb{sup -1} and 1.0 fb{sup -1}. The results are compared to perturbative QCD calculations in various approximations.

  17. Photonic-powered cable assembly

    Science.gov (United States)

    Sanderson, Stephen N.; Appel, Titus James; Wrye, IV, Walter C.

    2013-01-22

    A photonic-cable assembly includes a power source cable connector ("PSCC") coupled to a power receive cable connector ("PRCC") via a fiber cable. The PSCC electrically connects to a first electronic device and houses a photonic power source and an optical data transmitter. The fiber cable includes an optical transmit data path coupled to the optical data transmitter, an optical power path coupled to the photonic power source, and an optical feedback path coupled to provide feedback control to the photonic power source. The PRCC electrically connects to a second electronic device and houses an optical data receiver coupled to the optical transmit data path, a feedback controller coupled to the optical feedback path to control the photonic power source, and a photonic power converter coupled to the optical power path to convert photonic energy received over the optical power path to electrical energy to power components of the PRCC.

  18. Essentials of photonics

    CERN Document Server

    Rogers, Alan; Baets, Roel

    2008-01-01

    Photons and ElectronsHistorical SketchThe Wave Nature of LightPolarizationThe Electromagnetic SpectrumEmission and Absorption ProcessesPhoton Statistics The Behaviour of Electrons LasersSummaryWave Properties of LightThe Electromagnetic SpectrumWave RepresentationElectromagnetic WavesReflection and RefractionTotal Internal ReflectionInterference of LightLight WaveguidingInterferometersDiffractionGaussian Beams and Stable Optical ResonatorsPolarization OpticsThe Polarization EllipseCrystal OpticsRetarding WaveplatesA Variable Waveplate: The Soleil-Babinet Compensator Polarizing PrismsLinear BirefringenceCircular BirefringenceElliptical BirefringencePractical Polarization EffectsPolarization AnalysisThe Form of the Jones MatricesLight and Matter Emission, Propagation, and Absorption ProcessesClassical Theory of Light Propagation in Uniform Dielectric Media Optical Dispersion Emission and Absorption of LightOptical Coherence and CorrelationIntroductionMeasure of Coherence Wiener-Khinchin TheoremDual-Beam Interfe...

  19. Nonlocal structures: bilocal photon

    International Nuclear Information System (INIS)

    Clapp, R.E.

    1980-01-01

    It is postulated that all particles and fields are built from a single primitive field, a massless fermion with a σ spin of one-half. Two helicities are embodied in a tau spin of one-half. The vacuum is an open Fermi sea whose height is a wave number kappa. Elementary particles are structures having the form of standing-wave systems floating on the vacuum sea. A bilocal photon starts with a function describing two primitive quanta with parallel σ spin and opposite tau spin. A centroid-time wave equation then couples-in and infinite set of orthogonal functions. The introduction of an operator Qlambda permits the reduction of the infinite secular determinant to finite six-by-six determinant. Solutions are obtained describing photons with right-handed and left-handed polarizations. Electric and magnetic field vectors satisfying the vacuum Maxwell equations, are obtained from a bilocal Hertz vector. (author)

  20. Quantum communication with photons

    International Nuclear Information System (INIS)

    Tittel, W.

    2005-01-01

    Full text: The discovery that transmission of information encoded into single quantum systems enables new forms of communication let to the emergence of the domain of quantum communication. During the last ten years, various key experiments based on photons as carrier of the quantum information have been realized. Today, quantum cryptography systems based on faint laser pulses can be purchased commercially, bi-partite entanglement has been distributed over long distances and has been used for quantum key distribution, and quantum purification, teleportation and entanglement swapping have been demonstrated. I will give a general introduction into this fascinating field and will review experimental achievements in the domain of quantum communication with discrete two-level quantum systems (qubits) encoded into photons. (author)

  1. Photonics an introduction

    CERN Document Server

    Reider, Georg A

    2016-01-01

    This book provides a comprehensive introduction into photonics, from the electrodynamic and quantum mechanic fundamentals to the level of photonic components and building blocks such as lasers, amplifiers, modulators, waveguides, and detectors. The book will serve both as textbook and as a reference work for the advanced student or scientist. Theoretical results are derived from basic principles with convenient, yet state-of-the-art mathematical tools, providing not only deeper understanding but also familiarization with formalisms used in the relevant technical literature and research articles. Among the subject matters treated are polarization optics, pulse and beam propagation, waveguides, light–matter interaction, stationary and transient behavior of lasers, semiconductor optics and lasers (including low-dimensional systems such as quantum wells), detector technology, photometry, and colorimetry. Nonlinear optics are elaborated comprehensively. The book is intended for both students of physics and elect...

  2. MCNP: Photon benchmark problems

    International Nuclear Information System (INIS)

    Whalen, D.J.; Hollowell, D.E.; Hendricks, J.S.

    1991-09-01

    The recent widespread, markedly increased use of radiation transport codes has produced greater user and institutional demand for assurance that such codes give correct results. Responding to these pressing requirements for code validation, the general purpose Monte Carlo transport code MCNP has been tested on six different photon problem families. MCNP was used to simulate these six sets numerically. Results for each were compared to the set's analytical or experimental data. MCNP successfully predicted the analytical or experimental results of all six families within the statistical uncertainty inherent in the Monte Carlo method. From this we conclude that MCNP can accurately model a broad spectrum of photon transport problems. 8 refs., 30 figs., 5 tabs

  3. Nonlinear Photonic Crystal Fibers

    DEFF Research Database (Denmark)

    Hansen, Kim Per

    2004-01-01

    Despite the general recession in the global economy and the collapse of the optical telecommunication market, research within specialty fibers is thriving. This is, more than anything else, due to the technology transition from standard all-glass fibers to photonic crystal fibers, which, instead....... The freedom to design the dispersion profile of the fibers is much larger and it is possible to create fibers, which support only a single spatial mode, regardless of wavelength. In comparison, the standard dispersion-shifted fibers are limited by a much lower index-contrast between the core and the cladding...... in 1996, and are today on their way to become the dominating technology within the specialty fiber field. Whether they will replace the standard fiber in the more traditional areas like telecommunication transmission, is not yet clear, but the nonlinear photonic crystal fibers are here to stay....

  4. Natural photonic crystals

    Energy Technology Data Exchange (ETDEWEB)

    Vigneron, Jean Pol, E-mail: jean-pol.vigneron@fundp.ac.be [Research Center in Physics of Matter and Radiation (PMR), University of Namur (FUNDP), rue de Bruxelles, 61, B-5000 Namur (Belgium); Simonis, Priscilla [Research Center in Physics of Matter and Radiation (PMR), University of Namur (FUNDP), rue de Bruxelles, 61, B-5000 Namur (Belgium)

    2012-10-15

    Photonic structures appeared in nature several hundred millions years ago. In the living world, color is used for communication and this important function strongly impacts the individual chances of survival as well as the chances to reproduce. This has a statistical influence on species populations. Therefore, because they are involved in evolution, natural color-generating structures are - from some point of view - highly optimized. In this short review, a survey is presented of the development of natural photonic crystal-type structures occurring in insects, spiders, birds, fishes and other marine animals, in plants and more, from the standpoint of light-waves propagation. One-, two-, and three-dimensional structures will be reviewed with selected examples.

  5. PHOTON: A user's manual

    International Nuclear Information System (INIS)

    Chapman, D.

    1988-01-01

    PHOTON has proven very useful in the development of the X17 superconducting wiggler beamline. Its use has determined the shielding required from the wiggler device to the very end of the beamline in the hutches and angiography section. Doses calculated by this program have been compared with experimental results from conventional bending magnet beamline with great success. In each case the program consistently overestimated the dose by factors ranging from 2 to 10. The reason for this overestimation is understood and was not refined further in the program in order to maintain some level of safety in the shielding calculations. PHOTON should prove useful in the design of any beamline. Its ability to calculate power deposited and spectra transmitted through nearly arbitrary beamline configurations as well as the scattered radiation doses through shielding walls make it a very powerful tool

  6. Natural photonic crystals

    International Nuclear Information System (INIS)

    Vigneron, Jean Pol; Simonis, Priscilla

    2012-01-01

    Photonic structures appeared in nature several hundred millions years ago. In the living world, color is used for communication and this important function strongly impacts the individual chances of survival as well as the chances to reproduce. This has a statistical influence on species populations. Therefore, because they are involved in evolution, natural color-generating structures are - from some point of view - highly optimized. In this short review, a survey is presented of the development of natural photonic crystal-type structures occurring in insects, spiders, birds, fishes and other marine animals, in plants and more, from the standpoint of light-waves propagation. One-, two-, and three-dimensional structures will be reviewed with selected examples.

  7. Illuminating WISPs with photons

    International Nuclear Information System (INIS)

    Arias, Paola

    2011-10-01

    Physics beyond the Standard Model naturally gives rise to very light and weakly interacting particles, dubbed WISPs (Weakly Interacting Slim Particles). A prime example is the axion, that has eluded experimental detection for more than thirty years. In this talk we review some of the strongly motivated candidates for such particles, the observational hints for them and the present status of searches with photon regeneration experiments, as well as possible future improvements. (orig.)

  8. Manipulating atoms with photons

    International Nuclear Information System (INIS)

    Cohen-Tannoudji, C.N.

    1998-01-01

    The article is a translation of the lecture delivered on the occasion of the 1997 Nobel Prize awarding ceremony. The physical mechanisms which allow manipulating of neutral atoms with laser photons are described. A remark is also made concerning several possible applications of ultra-cool atoms and streams of future research. The article is completed by Prof. Cohen-Tannoudji's autobiography. (Z.J.)

  9. Three-photon micromasers

    International Nuclear Information System (INIS)

    Obada, A.S.F.; Abu Sitta, A.M.M.; Yasin, O.M.

    1993-01-01

    A non-degenerate 3-photon micromaser is analyzed. A 4-level atom is taken and 3 models of the field are considered. The model is solved for the case of resonance and the master equation for the density matrix is obtained. Semi-analytical solutions are obtained under specified approximations. Three modes can exist depending on the time of interaction. (author). 10 refs, 2 figs

  10. Mass of the photon

    International Nuclear Information System (INIS)

    Goldhaber, A.S.; Nieto, M.M.

    1976-01-01

    Several experiments are discussed for which results are equivalent to the catching and weighing of a photon. It is noted that none of the experiments has proved the rest mass to be zero and that such a proof may be impossible. It is shown by such experiments that the rest mass is less than the limit of accuracy of the experiment. These limits have approached ever closer to zero, and the most recent values are exceedingly small

  11. Photonic Molecule Lasers Revisited

    Science.gov (United States)

    Gagnon, Denis; Dumont, Joey; Déziel, Jean-Luc; Dubé, Louis J.

    2014-05-01

    Photonic molecules (PMs) formed by coupling two or more optical resonators are ideal candidates for the fabrication of integrated microlasers, photonic molecule lasers. Whereas most calculations on PM lasers have been based on cold-cavity (passive) modes, i.e. quasi-bound states, a recently formulated steady-state ab initio laser theory (SALT) offers the possibility to take into account the spectral properties of the underlying gain transition, its position and linewidth, as well as incorporating an arbitrary pump profile. We will combine two theoretical approaches to characterize the lasing properties of PM lasers: for two-dimensional systems, the generalized Lorenz-Mie theory will obtain the resonant modes of the coupled molecules in an active medium described by SALT. Not only is then the theoretical description more complete, the use of an active medium provides additional parameters to control, engineer and harness the lasing properties of PM lasers for ultra-low threshold and directional single-mode emission. We will extend our recent study and present new results for a number of promising geometries. The authors acknowledge financial support from NSERC (Canada) and the CERC in Photonic Innovations of Y. Messaddeq.

  12. The photon structure function

    International Nuclear Information System (INIS)

    Berger, C.

    1984-01-01

    In principle we have to distinguish between three cases: In no-tag experiments, none of the outgoing leptons e + e - is detected. The photon flux is completely dominated by transversely polarized photons, which are practically on-mass-shell. In single-tag experiments, either the outgoing e - or e + is detected in a forward spectrometer. Sometimes the tagging information is only used for separating a multihadronic twophoton final state from e + e - annihilation states. On the other hand, the information from the forward detectors can be used to investigate the Q 2 behaviour of the cross-section. A combination of tagging on one side with antitagging on the other allows an easy interpretation of the results in terms of electron scattering off a real photon target. In double-tag experiments, both outgoing leptons are measured. In principle, the full kinematical structure of the process can be studied, but we are still a long way from starting to tackle this difficult task

  13. Slotted Photonic Crystal Sensors

    Science.gov (United States)

    Scullion, Mark G.; Krauss, Thomas F.; Di Falco, Andrea

    2013-01-01

    Optical biosensors are increasingly being considered for lab-on-a-chip applications due to their benefits such as small size, biocompatibility, passive behaviour and lack of the need for fluorescent labels. The light guiding mechanisms used by many of them results in poor overlap of the optical field with the target molecules, reducing the maximum sensitivity achievable. This review article presents a new platform for optical biosensors, namely slotted photonic crystals, which provide higher sensitivities due to their ability to confine, spatially and temporally, the optical mode peak within the analyte itself. Loss measurements showed values comparable to standard photonic crystals, confirming their ability to be used in real devices. A novel resonant coupler was designed, simulated, and experimentally tested, and was found to perform better than other solutions within the literature. Combining with cavities, microfluidics and biological functionalization allowed proof-of-principle demonstrations of protein binding to be carried out. Higher sensitivities were observed in smaller structures than possible with most competing devices reported in the literature. This body of work presents slotted photonic crystals as a realistic platform for complete on-chip biosensing; addressing key design, performance and application issues, whilst also opening up exciting new ideas for future study. PMID:23503295

  14. Nonlinear photonic metasurfaces

    Science.gov (United States)

    Li, Guixin; Zhang, Shuang; Zentgraf, Thomas

    2017-03-01

    Compared with conventional optical elements, 2D photonic metasurfaces, consisting of arrays of antennas with subwavelength thickness (the 'meta-atoms'), enable the manipulation of light-matter interactions on more compact platforms. The use of metasurfaces with spatially varying arrangements of meta-atoms that have subwavelength lateral resolution allows control of the polarization, phase and amplitude of light. Many exotic phenomena have been successfully demonstrated in linear optics; however, to meet the growing demand for the integration of more functionalities into a single optoelectronic circuit, the tailorable nonlinear optical properties of metasurfaces will also need to be exploited. In this Review, we discuss the design of nonlinear photonic metasurfaces — in particular, the criteria for choosing the materials and symmetries of the meta-atoms — for the realization of nonlinear optical chirality, nonlinear geometric Berry phase and nonlinear wavefront engineering. Finally, we survey the application of nonlinear photonic metasurfaces in optical switching and modulation, and we conclude with an outlook on their use for terahertz nonlinear optics and quantum information processing.

  15. Slotted Photonic Crystal Sensors

    Directory of Open Access Journals (Sweden)

    Andrea Di Falco

    2013-03-01

    Full Text Available Optical biosensors are increasingly being considered for lab-on-a-chip applications due to their benefits such as small size, biocompatibility, passive behaviour and lack of the need for fluorescent labels. The light guiding mechanisms used by many of them results in poor overlap of the optical field with the target molecules, reducing the maximum sensitivity achievable. This review article presents a new platform for optical biosensors, namely slotted photonic crystals, which provide higher sensitivities due to their ability to confine, spatially and temporally, the optical mode peak within the analyte itself. Loss measurements showed values comparable to standard photonic crystals, confirming their ability to be used in real devices. A novel resonant coupler was designed, simulated, and experimentally tested, and was found to perform better than other solutions within the literature. Combining with cavities, microfluidics and biological functionalization allowed proof-of-principle demonstrations of protein binding to be carried out. Higher sensitivities were observed in smaller structures than possible with most competing devices reported in the literature. This body of work presents slotted photonic crystals as a realistic platform for complete on-chip biosensing; addressing key design, performance and application issues, whilst also opening up exciting new ideas for future study.

  16. Photon-activation therapy

    International Nuclear Information System (INIS)

    Fairchild, R.G.; Bond, V.P.

    1982-01-01

    Photon Activation Therapy (PAT) is a technique in which radiation dose to tumor is enhanced via introduction of stable 127 I in the form of iodinated deoxyuridine (IdUrd). Stimulation of cytotoxic effects from IdUrd is accomplished by activation with external (or implanted) radiation sources. Thus, accumulations of this nucleoside in actively competing cellpools do not preclude therapy in so far as such tissues can be excluded from the radiation field. Calculations show that 5% replacement of thymidine (Tyd) in tumor DNA should enhance the biological effectiveness of a given photon radiotherapy dose by a factor of approx. 3. Proportionally higher gains would result from higher replacements of Tyd and IdUrd. In addition, biological response is enhanced by chemical sensitization with IdUrd. The data indicate that damage from photon activation as well as chemical sensitization does not repair. Thus, at low dose rates, a further increase in therapeutic gain should accrue as normal tissues are allowed to repair and regenerate. A samarium-145 source has been developed for PAT, with activating x-ray energies of from 38 to 45 keV. Favorable clinical results can be expected through the use of IdUrd and protracted irradiations with low energy x-rays. In particular, PAT may provide unique advantages at selected sites such as brain, or head and neck tumors

  17. Beitraege zur Astronomiegeschichte, Band 5 (Acta Historica Astronomiae Vol. 18)

    Science.gov (United States)

    Duerbeck, H. W.; Dick, W. R.; Hamel, J.

    2003-01-01

    The 18th volume of the Acta Historica Astronomiae is at the same time the sixth collection of essays on the history of astronomy ("Beitræge zur Astronomiegeschichte, Band 6"), edited by the historians of astronomy W.R. Dick (Potsdam) and J. Hamel (Berlin). Besides a few short notices and book reviews, the book contains eight major articles, which deal with astronomical topics covering the time from the 16th to the 19th centuries. The first article by Michael Weichenhan (Berlin) deals with "the invention of the disk-shaped earth: a chapter of Copernican apologetics". The author shows that the concept of a "disc-shaped Earth" was by no means widespread in the middle ages, but restricted to the father of the church Lactantius and some adherents. Nevertheless, it was used by adherents of Copernicus to show the absurd consequences of a strictly literal biblical interpretation -- here concerning the Earth's shape, disc versus sphere, there the geocentric versus the heliocentric system. This thorough philosophical study is followed by two very short articles. "The measuring accuracy of Tycho's large sextant" by Johann Wünsch investigates O-C values of planet-star distances, as based on Tycho's observations as published in the Historia Coelestis (a compilation, which is also based on Tycho's manuscripts, and published in Regensburg in 1672). The result is that standard deviations are 80 arcseconds for Saturn and 89 arcseconds for Jupiter and Mars, an unexpectedly poor result in view of the general opinion that Tycho was famous for his precision work. "The astronomer Christoph Grienberger and the Galilei trial" by Franz Daxecker deals with a Jesuit astronomer who was both the disciple and successor of the mathematician-astronomer Christopher Clavius at the Collegium Romanum. While he was inclined to Galilei early on, he was forced to propagate Aristotelian doctrine. The brief article is very concise, but extremely tiresome to read (3 pages of pure text are embellished by

  18. INDIA: Photon multiplicity detector

    International Nuclear Information System (INIS)

    Anon.

    1995-01-01

    Full text: The team of Indian scientists from Calcutta's Variable Energy Cyclotron Centre, Bhubaneswar Institute of Physics, Panjab (Chandigarh), Rajasthan (Jaipur) and Jammu in collaboration with GSI Darmstadt have contributed a large and highly granular preshower photon multiplicity detector (PMD) for the WA98 experiment at the CERN SPS proton synchrotron. This experiment studies high energy collisions of lead ions and will measure both charged particle and photon multiplicity in a large overlap region. The motivation for measuring photon multiplicity in ultra-relativistic heavy ion collisions stems from theoretical predictions of changes in the relative production of photons and charged particles in the phase transition of hadronic matter to quarkgluon plasma and its subsequent hadronization. The photon multiplicity detector consists of a matrix of scintillator pads placed in light-tight boxes and mounted behind the lead converter plates. The light from the scintillator pads is transported to the readout system using wavelength shifting (WLS) fibres. Developing on the team's earlier experience with a smaller version for the WA93 experiment (September 1991, page 16), several modifications were incorporated to improve light collection and transport. Use of improved WLS fibres, short WLS pieces to minimize self-absorption, and thermal splicing with long clear fibres were some of the important changes incorporated. Tests showed signficantly improved light collection. The scintillator pads were fabricated at all the five collaborating centres in India and the complicated assembly in the detector box modules carried out at the Variable Energy Cyclotron Centre, Calcutta. More than 400 lead converter plates were machined in Calcutta to rigorous tolerances of 0.2 mm. The assembled detector box modules and lead plates were shipped to CERN in spring 1994 for tests and installation. The WA98 PMD consists of over 50,000 scintillator pads of sizes varying from 15 to

  19. INDIA: Photon multiplicity detector

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1995-01-15

    Full text: The team of Indian scientists from Calcutta's Variable Energy Cyclotron Centre, Bhubaneswar Institute of Physics, Panjab (Chandigarh), Rajasthan (Jaipur) and Jammu in collaboration with GSI Darmstadt have contributed a large and highly granular preshower photon multiplicity detector (PMD) for the WA98 experiment at the CERN SPS proton synchrotron. This experiment studies high energy collisions of lead ions and will measure both charged particle and photon multiplicity in a large overlap region. The motivation for measuring photon multiplicity in ultra-relativistic heavy ion collisions stems from theoretical predictions of changes in the relative production of photons and charged particles in the phase transition of hadronic matter to quarkgluon plasma and its subsequent hadronization. The photon multiplicity detector consists of a matrix of scintillator pads placed in light-tight boxes and mounted behind the lead converter plates. The light from the scintillator pads is transported to the readout system using wavelength shifting (WLS) fibres. Developing on the team's earlier experience with a smaller version for the WA93 experiment (September 1991, page 16), several modifications were incorporated to improve light collection and transport. Use of improved WLS fibres, short WLS pieces to minimize self-absorption, and thermal splicing with long clear fibres were some of the important changes incorporated. Tests showed signficantly improved light collection. The scintillator pads were fabricated at all the five collaborating centres in India and the complicated assembly in the detector box modules carried out at the Variable Energy Cyclotron Centre, Calcutta. More than 400 lead converter plates were machined in Calcutta to rigorous tolerances of 0.2 mm. The assembled detector box modules and lead plates were shipped to CERN in spring 1994 for tests and installation. The WA98 PMD consists of over 50,000 scintillator pads of sizes varying from 15 to 25 mm

  20. Photon-photon inclusive scattering and perturbative QCD

    International Nuclear Information System (INIS)

    Maor, U.

    1988-01-01

    Perturbative QCD expectations and problems associated with the study of the photon structure function data are reviewed. An assessment is given for the viability and sensitivity of photon-photon scattering as a decisive tool for the determination of the QCD scale. Particular attention is given to the theoretical problems of singularity cancellations at x = 0 and threshold-associated difficulties at x = 1 and their implications on the actual data analysis. It is concluded that the experimental results, while not providing a decisive verification of QCD at small distances, do add to other independent experiments which are all consistent with the theory and suggest a reasonably well defined QCD scale parameter. The importance of the small Q 2 limit to photon-photon analysis is discussed and the data are examined in an attempt to identify and isolate the contributions of the hadronic and point-like sectors of the target photon. 21 refs., 7 figs. (author)

  1. Medienkompetenz und E-Portfolios für die Sekundarstufe I – ein Weg zur Medienbildung

    Directory of Open Access Journals (Sweden)

    Bernhard Ertl

    2015-06-01

    Full Text Available Medienkompetenz und digital literacy gehören inzwischen zu den Schlüsselkompetenzen und sind ein Teil der Medienbildung von Kindern und Jugendlichen. Medienbildung und/oder die dazu gehörigen Kompetenzen werden jedoch in Lehrplänen oft unterschiedlich verortet und definiert. Hierbei stellt sich die Frage, inwieweit kompetenzorientiertes Lernen den Ansprüchen an Medienbildung gerecht wird bzw. zur Medienbildung beitragen kann. Das Projekt EUfolio implementiert E-Portfolios in verschiedenen europäischen Klassen der Sekundarstufe I und realisiert dabei einen integrativen, fächerübergreifenden Ansatz. Dieser zielt primär auf den Erwerb von Schlüsselqualifikationen, kann jedoch implizit, etwa im Rahmen des reflektierenden Lernens mit E-Portfolios, zur Medienbildung beitragen. Der Artikel charakterisiert die Konzepte der Medienkompetenz und Medienbildung und diskutiert auf Basis des Projekts Eufolio, wie kompetenzorientiertes Lernen mit E-Portfolios einen Beitrag zur Medienbildung leisten kann.

  2. S2k-Leitlinie zum Gebrauch von Präparationen zur lokalen Anwendung auf der Haut (Topika).

    Science.gov (United States)

    Wohlrab, Johannes; Staubach, Petra; Augustin, Matthias; Eisert, Lisa; Hünerbein, Andreas; Nast, Alexander; Reimann, Holger; Strömer, Klaus; Mahler, Vera

    2018-03-01

    Diese Leitlinie richtet sich an Assistenz- und Fachärzte der Dermatologie sowie an Kostenträger und politische Entscheidungsgremien. Die Leitlinie wurde im formellen Konsensusverfahren (S2k) von Dermatologen unter Einbindung von Apothekern erstellt. Die Leitlinie stellt allgemeine Aspekte der Pharmakokinetik sowie der regulatorischen Begrifflichkeiten dar. Es werden Empfehlungen zur Indikation von Magistralrezepturen sowie deren Qualitätssicherung gegeben. Die Bedeutung der galenischen Grundlagen und die Problematik bei einer Substitution gegeneinander verschiedener Grundlagen werden dargestellt. Die Leitlinie umfasst Kriterien zur Auswahl einer adäquaten Grundlage sowie spezifische Aspekte zur Therapieplanung. Die Leitlinie gibt Empfehlungen zum Management bei Unverträglichkeiten gegenüber Bestandteilen der Grundlagen oder Hilfsstoffe. © 2018 The Authors | Journal compilation © Blackwell Verlag GmbH, Berlin.

  3. Renewable energies in Germany. Data on the development in 2016; Erneuerbare Energien in Deutschland. Daten zur Entwicklung im Jahr 2016

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2017-03-15

    The Working Group on Renewable Energy Statistics (AGEE-Stat), which regularly evaluates the use of renewable energies on behalf of the German Federal Ministry of Economics and Energy, has made an initial assessment of the development of renewable energies in Germany on the basis of available, mostly provisional data of 2016. The present background paper describes the previous findings for the areas of electricity, heat and transport, supplemented by figures on economic significance as well as on emission reductions through renewable energies. [German] Die Arbeitsgruppe Erneuerbare Energien-Statistik (AGEE-Stat), die im Auftrag des Bundesministeriums fuer Wirtschaft und Energie regelmaessig die Nutzung der erneuerbaren Energien bilanziert, hat auf der Grundlage verfuegbarer, zumeist vorlaeufiger Daten eine erste Abschaetzung zur Entwicklung der erneuerbaren Energien in Deutschland im Jahr 2016 erstellt. Das vorliegende Hintergrundpapier beschreibt die bisherigen Erkenntnisse fuer die Bereiche Strom, Waerme und Verkehr, ergaenzt um Zahlen zur wirtschaftlichen Bedeutung sowie zur Emissionsvermeidung durch erneuerbare Energien.

  4. First Swiss bachelor in Photonics

    Science.gov (United States)

    Leutenegger, Tobias; Studer, Bruno

    2015-10-01

    Swissmem, the Swiss association of mechanical and electrical engineering industries, founded a new photonics group in 2013. This reflects the importance of this key technology for Switzerland. Swissmem requested from the Swiss Universities of Applied Sciences to introduce a new bachelor program to fulfill the increasing demand of the Swiss industry of young academics in the field of photonics. Optech Consulting is investigating the Swiss photonics market since many years on behalf of Swissphotonics, the Swiss national thematic network for photonics. The study concluded that the total production volume of the Swiss photonics industry in the year 2013 was 3 billion Swiss francs and a slight growth is expected for 2014. The University of Applied Science HTW Chur is located in the Eastern part of Switzerland. This area of the Rhine valley is a technology cluster of innovative companies in the field of optics and electronics. The industry is growing and the R&D departments of the worldwide active companies are lacking well-educated photonics engineers. The HTW Chur is dedicated to establish the first Swiss bachelor in Photonics. Supported by strong industrial players and an excellent network, the HTW Chur developed different job descriptions and a complete curriculum, which reflect the needs of the Swiss photonics industry. Almost 60% of the ECTS of this national degree program are assigned to photonics specific courses and the practical projects are organized in close collaboration with the photonics industry. Curriculum, job descriptions and the industrial needs will be discussed in detail in this paper.

  5. Optics of globular photonic crystals

    International Nuclear Information System (INIS)

    Gorelik, V S

    2007-01-01

    The results of experimental and theoretical studies of the optical properties of globular photonic crystals - new physical objects having a crystal structure with the lattice period exceeding considerably the atomic size, are presented. As globular photonic crystals, artificial opal matrices consisting of close-packed silica globules of diameter ∼200 nm were used. The reflection spectra of these objects characterising the parameters of photonic bands existing in these crystals in the visible spectral region are presented. The idealised models of the energy band structure of photonic crystals investigated in the review give analytic dispersion dependences for the group velocity and the effective photon mass in a globular photonic crystal. The characteristics of secondary emission excited in globular photonic crystals by monochromatic and broadband radiation are presented. The results of investigations of single-photon-excited delayed scattering of light observed in globular photonic crystals exposed to cw UV radiation and radiation from a repetitively pulsed copper vapour laser are presented. The possibilities of using globular photonic crystals as active media for lasing in different spectral regions are considered. It is proposed to use globular photonic crystals as sensitive sensors in optoelectronic devices for molecular analysis of organic and inorganic materials by the modern methods of laser spectroscopy. The results of experimental studies of spontaneous and stimulated globular scattering of light are discussed. The conditions for observing resonance and two-photon-excited delayed scattering of light are found. The possibility of accumulation and localisation of the laser radiation energy inside a globular photonic crystal is reported. (review)

  6. On the clinical impact of cerebral dopamine D{sub 2} receptor scintigraphy; Zur klinischen Wertigkeit der zerebralen Dopamin-D{sub 2}-Rezeptorszintigraphie

    Energy Technology Data Exchange (ETDEWEB)

    Larisch, R. [Duesseldorf Univ. (Germany). Klinik fuer Nuklearmedizin; Klimke, A. [Duesseldorf Univ. (Germany). Psychiatrische Klinik

    1998-12-31

    The present review describes findings and clinical indications for the dopamine D{sub 2} receptor scintigraphy. Methods for the examination of D{sub 2} receptors are positron emission tomography (PET) using {sup 11}C- or {sup 18}F-labelled butyrophenones or benzamides or single photon emission tomography (SPECT) using {sup 123}I-iodobenzamide (IBZM) respectively. The most important indication in neurology is the differential diagnosis of Parkinsonism: Patients with early Parkinson`s disease show an increased D{sub 2} receptor binding (D{sub 2}-RB) compared to control subjects. However, patients suffering from Steele-Richardson-Olszewski-Syndrome or Multiple System Atrophy show a decreased D{sub 2}-RB and are generally non-responsive to treatment. Postsynaptic blockade of D{sub 2} receptors results in a drug induced Parkinsonian syndrome, which can be diagnosed by D{sub 2} scintigraphy. Further possible indications occur in psychiatry: The assessment of receptor occupancy is useful in schizophrenic patients treated with neuroleptics. Additionally, D{sub 2} receptor scintigraphy might help to clarify the differential diagnosis between neuroleptic malignant syndrome and lethal catatonia. The method might be useful for supervising neurobiochemical changes in drug dependency and during withdrawal. Assessment of dopamine D{sub 2} receptor binding can simplify the choice of therapy in depressive disorder: Patients showing a low D{sub 2} binding are likely to improve following an antidepressive drug treatment whereas sleep deprivation is promising in patients with high D{sub 2} binding. (orig.) [Deutsch] Die vorliegende Arbeit gibt eine Uebersicht ueber Befunde und klinische Indikationen zur Dopamin-D{sub 2}-Rezeptorszintigraphie. Methoden zur Untersuchung der D{sub 2}-Rezeptoren sind die Positronen-Emissions-Tomographie (PET) mit {sup 11}C- oder {sup 18}F-markierten Butyrophenonen oder Benzamiden oder die Einzelphotonen-Emissions-Tomographie (SPECT) mit {sup 123}I

  7. Photon correlation in single-photon frequency upconversion.

    Science.gov (United States)

    Gu, Xiaorong; Huang, Kun; Pan, Haifeng; Wu, E; Zeng, Heping

    2012-01-30

    We experimentally investigated the intensity cross-correlation between the upconverted photons and the unconverted photons in the single-photon frequency upconversion process with multi-longitudinal mode pump and signal sources. In theoretical analysis, with this multi-longitudinal mode of both signal and pump sources system, the properties of the signal photons could also be maintained as in the single-mode frequency upconversion system. Experimentally, based on the conversion efficiency of 80.5%, the joint probability of simultaneously detecting at upconverted and unconverted photons showed an anti-correlation as a function of conversion efficiency which indicated the upconverted photons were one-to-one from the signal photons. While due to the coherent state of the signal photons, the intensity cross-correlation function g(2)(0) was shown to be equal to unity at any conversion efficiency, agreeing with the theoretical prediction. This study will benefit the high-speed wavelength-tunable quantum state translation or photonic quantum interface together with the mature frequency tuning or longitudinal mode selection techniques.

  8. Photon technology. Laser process technology; Photon technology. Laser process gijutsu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-03-01

    For developing laser process technology by interaction between substance and photon, the present state, system, R and D issues and proposal of such technology were summarized. Development of the photon technology aims at the modification of bonding conditions of substances by quantum energy of photon, and the new process technology for generating ultra- high temperature and pressure fields by concentrating photon on a minute region. Photon technology contributes to not only the conventional mechanical and thermal forming and removal machining but also function added machining (photon machining) in quantum level and new machining technology ranging from macro- to micro-machining, creating a new industrial field. This technology extends various fields from the basis of physics and chemistry to new bonding technology. Development of a compact high-quality high-power high-efficiency photon source, and advanced photon transmission technology are necessary. The basic explication of an unsolved physicochemical phenomenon related to photon and substance, and development of related application technologies are essential. 328 refs., 147 figs., 13 tabs.

  9. Resonant Photonic States in Coupled Heterostructure Photonic Crystal Waveguides

    Directory of Open Access Journals (Sweden)

    Sabarinathan J

    2010-01-01

    Full Text Available Abstract In this paper, we study the photonic resonance states and transmission spectra of coupled waveguides made from heterostructure photonic crystals. We consider photonic crystal waveguides made from three photonic crystals A, B and C, where the waveguide heterostructure is denoted as B/A/C/A/B. Due to the band structure engineering, light is confined within crystal A, which thus act as waveguides. Here, photonic crystal C is taken as a nonlinear photonic crystal, which has a band gap that may be modified by applying a pump laser. We have found that the number of bound states within the waveguides depends on the width and well depth of photonic crystal A. It has also been found that when both waveguides are far away from each other, the energies of bound photons in each of the waveguides are degenerate. However, when they are brought close to each other, the degeneracy of the bound states is removed due to the coupling between them, which causes these states to split into pairs. We have also investigated the effect of the pump field on photonic crystal C. We have shown that by applying a pump field, the system may be switched between a double waveguide to a single waveguide, which effectively turns on or off the coupling between degenerate states. This reveals interesting results that can be applied to develop new types of nanophotonic devices such as nano-switches and nano-transistors.

  10. Klinische Studie zur Messung der Dimensionsstabilität von digitalen Ganzkieferabformungen und die Entwicklung einer neuen Messmethode

    OpenAIRE

    Kuhr, Fabian

    2016-01-01

    Digitale Abformungen mit intraoralen Scannern haben klinisch bereits bewiesen, dass sie einzelne Zähne detail- und dimensionsgenau aufnehmen und in dieser Hinsicht eine Alternative zur konventionellen zahnärztlichen Abformung bieten können. Ob dies klinisch auch mit dem Scannen gesamter Zahnreihen möglich ist, wurde bislang nicht untersucht. Sowohl für konventionelle wie auch für digitale Abformungen gibt es keine In-vivo-Studie, die eine Methode zur Überprüfung der dimensionsgetreuen Übertra...

  11. Photon-splitting cross sections

    International Nuclear Information System (INIS)

    Johannessen, A.M.; Mork, K.J.; Overbo, I.

    1980-01-01

    The differential cross section for photon splitting (scattering of one photon into two photons) in a Coulomb field, obtained earlier by Shima, has been integrated numerically to yield various differential cross sections. Energy spectra differential with respect to the energy of one of the outgoing photons are presented for several values of the primary photon energy. Selected examples of recoil momentum distributions and some interesting doubly or multiply differential cross sections are also given. Values for the total cross section are obtained essentially for all energies. The screening effect caused by atomic electrons is also taken into account, and is found to be important for high energies, as in e + e - pair production. Comparisons with various approximate results obtained by previous authors mostly show fair agreement. We also discuss the possibilities for experimental detection and find the most promising candidate to be a measurement of both photons, and their energies, at a moderately high energy

  12. Very energetic photons at HERA

    International Nuclear Information System (INIS)

    Bawa, A.C.; Krawczyk, M.

    1991-01-01

    We show that every energetic photons in the backward direction can be produced in deep inelastic Compton scattering at HERA. Assuming a fixed energy of 9 GeV for the initial photons and 820 GeV for the protons a high rate is found for the production of final photons with a transverse momentum equal to 5 GeV/c and energy between 40 GeV and 300 GeV. These energetic photons arise mainly from the scattering of the soft gluonic constituents of the initial photon with quarks from the proton. They are produced in the backward direction in coincidence with a photon beam jet of energy ∝ 9 GeV in the forward direction. (orig.)

  13. All-photonic quantum repeaters

    Science.gov (United States)

    Azuma, Koji; Tamaki, Kiyoshi; Lo, Hoi-Kwong

    2015-01-01

    Quantum communication holds promise for unconditionally secure transmission of secret messages and faithful transfer of unknown quantum states. Photons appear to be the medium of choice for quantum communication. Owing to photon losses, robust quantum communication over long lossy channels requires quantum repeaters. It is widely believed that a necessary and highly demanding requirement for quantum repeaters is the existence of matter quantum memories. Here we show that such a requirement is, in fact, unnecessary by introducing the concept of all-photonic quantum repeaters based on flying qubits. In particular, we present a protocol based on photonic cluster-state machine guns and a loss-tolerant measurement equipped with local high-speed active feedforwards. We show that, with such all-photonic quantum repeaters, the communication efficiency scales polynomially with the channel distance. Our result paves a new route towards quantum repeaters with efficient single-photon sources rather than matter quantum memories. PMID:25873153

  14. Higgs-photon resonances

    Energy Technology Data Exchange (ETDEWEB)

    Dobrescu, Bogdan A.; Fox, Patrick J.; Kearney, John [Fermilab, Theoretical Physics Department, Batavia, IL (United States)

    2017-10-15

    We study models that produce a Higgs boson plus photon (h{sup 0}γ) resonance at the LHC. When the resonance is a Z{sup '} boson, decays to h{sup 0}γ occur at one loop. If the Z{sup '} boson couples at tree level to quarks, then the h{sup 0}γ branching fraction is typically of order 10{sup -5} or smaller. Nevertheless, there are models that would allow the observation of Z{sup '} → h{sup 0}γ at √(s) = 13 TeV with a cross section times branching fraction larger than 1 fb for a Z{sup '} mass in the 200-450 GeV range, and larger than 0.1 fb for a mass up to 800 GeV. The one-loop decay of the Z{sup '} into lepton pairs competes with h{sup 0}γ, even if the Z{sup '} couplings to leptons vanish at tree level. We also present a model in which a Z{sup '} boson decays into a Higgs boson and a pair of collimated photons, mimicking an h{sup 0}γ resonance. In this model, the h{sup 0}γ resonance search would be the discovery mode for a Z{sup '} as heavy as 2 TeV. When the resonance is a scalar, although decay to h{sup 0}γ is forbidden by angular momentum conservation, the h{sup 0} plus collimated photons channel is allowed. We comment on prospects of observing an h{sup 0}γ resonance through different Higgs decays, on constraints from related searches, and on models where h{sup 0} is replaced by a nonstandard Higgs boson. (orig.)

  15. Quantum Dot Photonics

    Science.gov (United States)

    Kinnischtzke, Laura A.

    We report on several experiments using single excitons confined to single semiconductor quantum dots (QDs). Electric and magnetic fields have previously been used as experimental knobs to understand and control individual excitons in single quantum dots. We realize new ways of electric field control by changing materials and device geometry in the first two experiments with strain-based InAs QDs. A standard Schottky diode heterostructure is demonstrated with graphene as the Schottky gate material, and its performance is bench-marked against a diode with a standard gate material, semi-transparent nickel-chromium (NiCr). This change of materials increases the photon collection rate by eliminating absorption in the metallic NiCr layer. A second set of experiments investigates the electric field response of QDs as a possible metrology source. A linear voltage potential drop in a plane near the QDs is used to describe how the spatially varying voltage profile is also imparted on the QDs. We demonstrate a procedure to map this voltage profile as a preliminary route towards a full quantum sensor array. Lastly, InAs QDs are explored as potential spin-photon interfaces. We describe how a magnetic field is used to realize a reversible exchange of information between light and matter, including a discussion of the polarization-dependence of the photoluminesence, and how that can be linked to the spin of a resident electron or hole. We present evidence of this in two wavelength regimes for InAs quantum dots, and discuss how an external magnetic field informs the spin physics of these 2-level systems. This thesis concludes with the discovery of a new class of quantum dots. As-yet unidentified defect states in single layer tungsten diselenide (WSe 2 ) are shown to host quantum light emission. We explore the spatial extent of electron confinement and tentatively identify a radiative lifetime of 1 ns for these single photon emitters.

  16. Nuclear studies with tagged photons

    International Nuclear Information System (INIS)

    Axel, P.

    1979-01-01

    First, the photon tagging technique will be described schematically, and a brief history of photon tagging will be given, including the 20 year development of this technique at Illinois. In the second part some typical operating conditions will be indicated for our tagged photon facility. The final section of this paper will illustrate some types of experiments by showing data obtained recently. (KBE) 891 KBE/KBE 892 ARA

  17. Direct photons in WA98

    CERN Document Server

    Aggarwal, M M; Ahammed, Z; Angelis, Aris L S; Antonenko, V G; Arefev, V; Astakhov, V A; Avdeichikov, V; Awes, T C; Baba, P V K S; Badyal, S K; Barlag, C; Bathe, S; Batyunya, B; Bernier, T; Bhalla, K B; Bhatia, V S; Blume, C; Bock, R; Bohne, E M; Böröcz, Z K; Bucher, D; Buijs, A; Büsching, H; Carlén, L; Chalyshev, V; Chattopadhyay, S; Cherbachev, R; Chujo, T; Claussen, A; Das, A C; Decowski, M P; Delagrange, H; Dzhordzhadze, V; Dönni, P; Dubovik, I; Dutt, S; Dutta-Majumdar, M R; El-Chenawi, K F; Eliseev, S; Enosawa, K; Foka, P Y; Fokin, S L; Ganti, M S; Garpman, S; Gavrishchuk, O P; Geurts, F J M; Ghosh, T K; Glasow, R; Gupta, S K; Guskov, B; Gustafsson, Hans Åke; Gutbrod, H H; Higuchi, R; Hrivnacova, I; Ippolitov, M S; Kalechofsky, H; Kamermans, R; Kampert, K H; Karadzhev, K; Karpio, K; Kato, S; Kees, S; Klein-Bösing, C; Knoche, S; Kolb, B W; Kosarev, I G; Kucheryaev, I; Krümpel, T; Kugler, A; Kulinich, P A; Kurata, M; Kurita, K; Kuzmin, N A; Langbein, I; Lee, Y Y; Löhner, H; Luquin, Lionel; Mahapatra, D P; Man'ko, V I; Martin, M; Martínez, G; Maksimov, A; Mgebrishvili, G; Miake, Y; Mir, M F; Mishra, G C; Miyamoto, Y; Mohanty, B; Morrison, D; Mukhopadhyay, D S; Naef, H; Nandi, B K; Nayak, S K; Nayak, T K; Neumaier, S; Nyanin, A; Nikitin, V A; Nikolaev, S; Nilsson, P O; Nishimura, S; Nomokonov, V P; Nystrand, J; Obenshain, F E; Oskarsson, A; Otterlund, I; Pachr, M; Pavlyuk, S; Peitzmann, Thomas; Petracek, V; Pinganaud, W; Plasil, F; Von Poblotzki, U; Purschke, M L; Rak, J; Raniwala, R; Raniwala, S; Ramamurthy, V S; Rao, N K; Retière, F; Reygers, K; Roland, G; Rosselet, L; Rufanov, I A; Roy, C; Rubio, J M; Sako, H; Sambyal, S S; Santo, R; Sato, S; Schlagheck, H; Schmidt, H R; Schutz, Y; Shabratova, G; Shah, T H; Sibiryak, Yu; Siemiarczuk, T; Silvermyr, D; Sinha, B C; Slavin, N V; Söderström, K; Solomey, Nickolas; Sood, G; Sørensen, S P; Stankus, P; Stefanek, G; Steinberg, P; Stenlund, E; Stüken, D; Sumbera, M; Svensson, S; Trivedi, M D; Tsvetkov, A A; Tykarski, L; Urbahn, J; Van den Pijll, E C; van Eijndhoven, N; van Nieuwenhuizen, G J; Vinogradov, A; Viyogi, Y P; Vodopyanov, A S; Vörös, S; Wyslouch, B; Yagi, K; Yokota, Y; Young, G R

    2002-01-01

    A measurement of direct photon production in /sup 208/Pb+/sup 208/Pb collisions at 158 A GeV has been carried out in the CERN WA98 experiment. The invariant yield of direct photons was extracted as a function of transverse momentum in the interval 0.51.5 GeV/c. the result constitutes the first observation of direct photons in ultrarelativistic heavy-ion collisions. (19 refs).

  18. Silicon photonic integration in telecommunications

    Directory of Open Access Journals (Sweden)

    Christopher Richard Doerr

    2015-08-01

    Full Text Available Silicon photonics is the guiding of light in a planar arrangement of silicon-based materials to perform various functions. We focus here on the use of silicon photonics to create transmitters and receivers for fiber-optic telecommunications. As the need to squeeze more transmission into a given bandwidth, a given footprint, and a given cost increases, silicon photonics makes more and more economic sense.

  19. CERN manufactured hybrid photon detectors

    CERN Multimedia

    Maximilien Brice

    2004-01-01

    These hybrid photon detectors (HPDs) produce an electric signal from a single photon. An electron is liberated from a photocathode and accelerated to a silicon pixel array allowing the location of the photon on the cathode to be recorded. The electronics and optics for these devices have been developed in close collaboration with industry. HPDs have potential for further use in astrophysics and medical imaging.

  20. Nanodiamond Emitters of Single Photons

    Directory of Open Access Journals (Sweden)

    Vlasov I.I.

    2015-01-01

    Full Text Available Luminescence properties of single color centers were studied in nanodiamonds of different origin. It was found that single photon emitters could be realized even in molecularsized diamond (less than 2 nm capable of housing stable luminescent center “silicon-vacancy.” First results on incorporation of single-photon emitters based on luminescent nanodiamonds in plasmonic nanoantennas to enhance the photon count rate and directionality, diminish the fluorescence decay time, and provide polarization selectivity are presented.

  1. Spaceborne Photonics Institute

    Science.gov (United States)

    Venable, D. D.; Farrukh, U. O.; Han, K. S.; Hwang, I. H.; Jalufka, N. W.; Lowe, C. W.; Tabibi, B. M.; Lee, C. J.; Lyons, D.; Maclin, A.

    1994-01-01

    This report describes in chronological detail the development of the Spaceborne Photonics Institute as a sustained research effort at Hampton University in the area of optical physics. This provided the research expertise to initiate a PhD program in Physics. Research was carried out in the areas of: (1) modelling of spaceborne solid state laser systems; (2) amplified spontaneous emission in solar pumped iodine lasers; (3) closely simulated AM0 CW solar pumped iodine laser and repeatedly short pulsed iodine laser oscillator; (4) a materials spectroscopy and growth program; and (5) laser induced fluorescence and atomic and molecular spectroscopy.

  2. Complex photonic structures

    International Nuclear Information System (INIS)

    Wiersma, D.S.

    2013-01-01

    We discuss in detail the optical properties of complex photonic structures, in particular those with a dominating disorder component. We will focus on their general transport properties, as well as on their use as light sources (random lasers). The basis for the theory of multiple light scattering in random systems will be explained as a tutorial introduction to the topic, including the explicit calculation of the effect of coherent backscattering. We will discuss various structures that go beyond regular disordered ones, in particular Levy glasses, liquid crystals, and quasicrystals, and show examples of their optical properties both from a conceptual and practical point of view.

  3. Photon mass and electrogenesis

    International Nuclear Information System (INIS)

    Dolgov, Alexander; Pelliccia, Diego N.

    2007-01-01

    We show that if the photon possesses a tiny but non-vanishing mass, the universe cannot be electrically neutral. A cosmological electric asymmetry could be generated either at an early stage by the different evaporation rates of the primordial black holes with respect to positively and negatively charged particles or by a predominant capture of protons in comparison to electrons by the heavy galactic black holes in the contemporary universe. An impact of this phenomenon on the generation of large scale magnetic fields and on the acceleration of the universe is considered

  4. Fluctuations and Photons

    International Nuclear Information System (INIS)

    Gupta, Sourendu

    2007-01-01

    In this talk I discuss measures of fluctuations, especially those leading to the proof that the quark gluon plasma indeed contains quarks. I discuss the quark mass dependence of the critical end point of QCD. Then I discuss probes of the QCD critical point. Non-gaussian behaviour of event-to-event fluctuations of conserved quantum numbers is one such probe. Another is due to the coupling of fluctuations in baryon number and electrical charge, giving rise to long range random fluctuations of local charge density which relax slowly. These fluctuations can scatter photons, giving rise to critical opalescence

  5. Fluctuations and Photons

    Science.gov (United States)

    Gupta, Sourendu

    2007-02-01

    In this talk I discuss measures of fluctuations, especially those leading to the proof that the quark gluon plasma indeed contains quarks. I discuss the quark mass dependence of the critical end point of QCD. Then I discuss probes of the QCD critical point. Non-gaussian behaviour of event-to-event fluctuations of conserved quantum numbers is one such probe. Another is due to the coupling of fluctuations in baryon number and electrical charge, giving rise to long range random fluctuations of local charge density which relax slowly. These fluctuations can scatter photons, giving rise to critical opalescence.

  6. Fluctuations and Photons

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, Sourendu [Department of Theoretical Physics, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005 (India)

    2007-02-15

    In this talk I discuss measures of fluctuations, especially those leading to the proof that the quark gluon plasma indeed contains quarks. I discuss the quark mass dependence of the critical end point of QCD. Then I discuss probes of the QCD critical point. Non-gaussian behaviour of event-to-event fluctuations of conserved quantum numbers is one such probe. Another is due to the coupling of fluctuations in baryon number and electrical charge, giving rise to long range random fluctuations of local charge density which relax slowly. These fluctuations can scatter photons, giving rise to critical opalescence.

  7. Dirac tensor with heavy photon

    Energy Technology Data Exchange (ETDEWEB)

    Bytev, V.V.; Kuraev, E.A. [Joint Institute of Nuclear Research, Moscow (Russian Federation). Bogoliubov Lab. of Theoretical Physics; Scherbakova, E.S. [Hamburg Univ. (Germany). 1. Inst. fuer Theoretische Physik

    2012-01-15

    For the large-angles hard photon emission by initial leptons in process of high energy annihilation of e{sup +}e{sup -} {yields} to hadrons the Dirac tensor is obtained, taking into account the lowest order radiative corrections. The case of large-angles emission of two hard photons by initial leptons is considered. This result is being completed by the kinematics case of collinear hard photons emission as well as soft virtual and real photons and can be used for construction of Monte-Carlo generators. (orig.)

  8. Recent photon results from ATLAS

    CERN Document Server

    Glasman, Claudia; The ATLAS collaboration

    2017-01-01

    The production of prompt isolated photons at hadron colliders provides a stringent test of perturbative QCD and can be used to probe the gluon density function of the proton. The ATLAS collaboration has performed precise measurements of the inclusive production o f isolated prompt photons at a center-of-mass energy of 13 TeV, differential in both rap idity and the photon transverse momentum. In addition, the integrated and differential c ross sections for isolated photon pair production 8 TeV have been measured. The results are compared with state-of-the-art theory predictions at NLO in QCD and with predictions of several MC generators.

  9. Physics with Photons at the ATLAS experiment

    International Nuclear Information System (INIS)

    Perez-Reale, V.

    2008-01-01

    The identification of photons in the ATLAS experiment is crucial for the study of a number of physics channels, including the search for a Higgs boson decaying to photon pairs, and measurements of direct production of single photons and photon pairs. The photon-photon and photon-jet channels are interesting in their own right, allowing the study of QCD at the new energy range of the LHC. The photon-identification strategy in ATLAS will be presented along with photon-jet cross section measurements and the potential ATLAS constrains on the gluon structure function

  10. Indications for surgical resection of benign pancreatic tumors; Indikationen zur chirurgischen Therapie benigner Pankreastumoren

    Energy Technology Data Exchange (ETDEWEB)

    Isenmann, R.; Henne-Bruns, D. [Chirurgische Universitaetsklinik, Klinik fuer Allgemein-, Viszeral- und Transplantationschirurgie, Ulm (Germany)

    2008-08-15

    Benign pancreatic tumors should undergo surgical resection when they are symptomatic or - in the case of incidental discovery - bear malignant potential. This is the case for the majority of benign pancreatic tumors, especially for intraductal papillary mucinous neoplasms or mucinous cystic adenomas. In addition, resection is indicated for all tumors where preoperative diagnostic fails to provide an exact classification. Several different operative techniques are available. The treatment of choice depends on the localization of the tumor, its size and on whether there is evidence of malignant transformation. Partial duodenopancreatectomy is the oncological treatment of choice for tumors of the pancreatic head whereas for tumors of the pancreatic tail a left-sided pancreatectomy is appropriate. Middle pancreatectomy or duodenum-preserving resection of the pancreatic head is not a radical oncologic procedure. They should only be performed in cases of tumors without malignant potential. (orig.) [German] Die Indikationsstellung zur Resektion benigner Pankreastumoren ist gegeben, wenn es sich um einen symptomatischen Tumor handelt oder - bei einem Zufallsbefund - um einen Tumor mit Potenzial zur malignen Entartung. Dies besteht bei der Mehrzahl der benignen Pankreastumoren, insbesondere bei der intraduktalen papillaeren muzinoesen Neoplasie (IPMN) oder muzinoesen Zystadenomen. Operativer Abklaerung beduerfen auch Tumoren, die unter Ausschoepfung aller diagnostischer Moeglichkeiten nicht eindeutig klassifizierbar sind. An chirurgischen Therapieverfahren stehen verschiedene Techniken zur Verfuegung. Die Wahl des Verfahren haengt von der Groesse und Lokalisation des Tumors ab und von der Frage, ob eine maligne Entartung bereits stattgefunden hat. Das onkologisch korrekte Standardresektionsverfahren bei Tumoren des Pankreaskopfes ist die partielle Duodenopankreatektomie, bei Tumoren des Pankreasschwanzes die Pankreaslinksresektion. Eine segmentale Resektion des

  11. Prüfungen zur Beurteilung der Brandgefahr; Anleitung für die Aufstellung von Anforderungen und Prüfbestimmungen zur Beurteilung der Brandgefahr von elektrotechnischen Erzeugnissen; 1-2: Anleitung für Bauelemente der Elektronik; Identisch mit IEC 60695-1-2, Ausgabe 1982

    CERN Document Server

    Deutsches Institut für Normung. Berlin

    1986-01-01

    Prüfungen zur Beurteilung der Brandgefahr; Anleitung für die Aufstellung von Anforderungen und Prüfbestimmungen zur Beurteilung der Brandgefahr von elektrotechnischen Erzeugnissen; 1-2: Anleitung für Bauelemente der Elektronik; Identisch mit IEC 60695-1-2, Ausgabe 1982

  12. Prüfungen zur Beurteilung der Brandgefahr; Beispiele für Verfahren zur Beurteilung einer Brandgefahr und für die Auslegung von Ergebnissen; 3.1: Kennwerte der Verbrennung und Übersicht über Prüfverfahren zu ihrer Ermittlung; Identisch mit IEC 60695-3-1, Ausgabe 1982

    CERN Document Server

    Deutsches Institut für Normung. Berlin

    1986-01-01

    Prüfungen zur Beurteilung der Brandgefahr; Beispiele für Verfahren zur Beurteilung einer Brandgefahr und für die Auslegung von Ergebnissen; 3.1: Kennwerte der Verbrennung und Übersicht über Prüfverfahren zu ihrer Ermittlung; Identisch mit IEC 60695-3-1, Ausgabe 1982

  13. Photon Differentials in Space and Time

    DEFF Research Database (Denmark)

    Schjøth, Lars; Frisvad, Jeppe Revall; Erleben, Kenny

    2011-01-01

    We present a novel photon mapping algorithm for animations. We extend our previous work on photon differentials [12] with time differentials. The result is a first order model of photon cones in space an time that effectively reduces the number of required photons per frame as well as efficiently...... reduces temporal aliasing without any need for in-between-frame photon maps....

  14. Two-dimensional 'photon fluid': effective photon-photon interaction and physical realizations

    International Nuclear Information System (INIS)

    Chiao, R Y; Hansson, T H; Leinaas, J M; Viefers, S

    2004-01-01

    We describe a recently developed effective theory for atom-mediated photon-photon interactions in a two-dimensional 'photon fluid' confined to a Fabry-Perot resonator. The photons in the lowest longitudinal cavity mode will appear as massive bosons interacting via a renormalized delta-function potential with a strength determined by physical parameters such as the density of atoms and the detuning of the photons relative to the resonance frequency of the atoms. We discuss novel quantum phenomena for photons, such as Bose-Einstein condensation and bound state formation, as well as possible experimental scenarios based on Rydberg atoms in a microwave cavity, or alkali atoms in an optical cavity

  15. Deterministically swapping frequency-bin entanglement from photon-photon to atom-photon hybrid systems

    Science.gov (United States)

    Ou, Bao-Quan; Liu, Chang; Sun, Yuan; Chen, Ping-Xing

    2018-02-01

    Inspired by the recent developments of the research on the atom-photon quantum interface and energy-time entanglement between single-photon pulses, we are motivated to study the deterministic protocol for the frequency-bin entanglement of the atom-photon hybrid system, which is analogous to the frequency-bin entanglement between single-photon pulses. We show that such entanglement arises naturally in considering the interaction between a frequency-bin entangled single-photon pulse pair and a single atom coupled to an optical cavity, via straightforward atom-photon phase gate operations. Its anticipated properties and preliminary examples of its potential application in quantum networking are also demonstrated. Moreover, we construct a specific quantum entanglement witness tool to detect such extended frequency-bin entanglement from a reasonably general set of separable states, and prove its capability theoretically. We focus on the energy-time considerations throughout the analysis.

  16. Egypt`s potential for geothermal energy use and underground storage of thermal energy; Moeglichkeiten zur Nutzung geothermischer Energie und zur unterirdischen thermischen Energiespeicherung in Aegypten

    Energy Technology Data Exchange (ETDEWEB)

    Abbas, A M; Sanner, B; Knoblich, K [Giessen Univ. (Germany). Inst. fuer Angewandte Geowissenschaften

    1997-12-01

    Egypt belongs to the arid to extremely arid zone. Hot springs or wells are chiefly distributed over the areas of the Golf of Suez shoreline, along the Red Sea coast and in the Bahariya, Dakhla and Kharga oasis in the Western Desert. The Red Sea with it`s branches into the Gulf of Suez and the Gulf of Aqaba/Jordan valley is the northern end of the East African Rift, which is tectonically active and yields further south known geothermal resources (e.g. in Kenya). Thus, a relatively high het flow zone exists on the eastern border of the Gulf of Suez, on Sinai peninsula. The hot springs of Ayun Musa, Hammam Faraon and El Sokhna are located there. Hammam Faroun is the hottest spring in Egypt with water temperature of approx. 70 C. This paper compiles previous studies from Egypt to elucidate the geothermal potential of Egypt and opportunities to make use of it. (orig.) [Deutsch] Aegypten gehoert zur ariden bis extrem ariden Zone. Heisse Quellen oder erbohrte heisse Waesser finden sich hauptsaechlich entlang der Kueste des Golfs von Suez und des Roten Meeres, sowie in den Oasen Bahariya, Dakhla und Kharga in der westlichen Wueste. Das Rote Meer mit seinen Verzweigungen in den Golf von Suez und in den Golf von Akaba/Jordangraben bildet den noerdlichen Abschluss des Ostafrikanischen Grabensystems, das tektonisch sehr aktiv ist und weiter suedlich (z.B. in Kenia) bekannte geothermische Ressourcen bietet. Eine Zone mit hohem geothermischen Waermefluss befindet sich dementsprechend auch am oestlichen Rand des Golfs von Suez, der zur Halbinsel Sinai gehoehrt. Hier werden die heissen Quellen von Ayun Musa, Hammam Faraon und El Sokhna angetroffen. Hammam Faraon ist die heisseste Quelle Aegyptens mit Wassertemperaturen von etwa 70 C. Die vorliegende Arbeit versucht, einige fruehere Studien aus Aegypten zusammenzufassen und das geothermische Potential Aegyptens mit den Moeglichkeiten seiner Nutzung aufzuzeigen. (orig.)

  17. Photonic band gap engineering in 2D photonic crystals

    Indian Academy of Sciences (India)

    -dimensional photonic crystals with square lattices composed of air holes in dielectric and vice versa i.e., dielectric rods in air, using the plane-wave expansion method are investigated. We then study, how the photonic band gap size is ...

  18. Waveguide superconducting single-photon autocorrelators for quantum photonic applications

    NARCIS (Netherlands)

    Sahin, D.; Gaggero, A.; Frucci, G.; Jahanmirinejad, S.; Sprengers, J.P.; Mattioli, F.; Leoni, R.; Beetz, J.; Lermer, M.; Kamp, M.; Höfling, S.; Fiore, A.; Hasan, Z.U.; Hemmer, P.R.; Lee, H.; Santori, C.M.

    2013-01-01

    We report a novel component for integrated quantum photonic applications, a waveguide single-photon autocorrelator. It is based on two superconducting nanowire detectors patterned onto the same GaAs ridge waveguide. Combining the electrical output of the two detectors in a correlation card enables

  19. Non-Poissonian photon statistics from macroscopic photon cutting materials

    NARCIS (Netherlands)

    De Jong, Mathijs; Meijerink, A; Rabouw, Freddy T.

    2017-01-01

    In optical materials energy is usually extracted only from the lowest excited state, resulting in fundamental energy-efficiency limits such as the Shockley-Queisser limit for single-junction solar cells. Photon-cutting materials provide a way around such limits by absorbing high-energy photons and

  20. Exclusive Channels in Photon-Photon Collisions at LEP

    OpenAIRE

    Braccini, Saverio

    2002-01-01

    The study of exclusive channels in photon-photon collisions at e+e- colliders allows to investigate the structure and the properties of hadrons in a very clean experimental environment. A concise review of the most recent results obtained at LEP is presented.

  1. Quantum photonics with quantum dots in photonic wires

    DEFF Research Database (Denmark)

    Munsch, Mathieu; Kuhlmann, Andreas; Cadeddu, Davide

    2016-01-01

    We present results from the spectroscopy of a single quantum dot in a photonic wire. The device presents a high photon extraction efficiency, and strong hybrid coupling to mechanical modes. We use resonance fluorescence to probe the emitter’s properties with the highest sensitivity. Weperform...

  2. Sidewall roughness measurement of photonic wires and photonic crystals

    DEFF Research Database (Denmark)

    Svalgaard, Mikael; Frandsen, Lars Hagedorn; Garnæs, Jørgen

    2007-01-01

    The performance of nanophotonic building blocks such as photonic wires and photonic crystals are rapidly improving, with very low propagation loss and very high cavity Q-factors being reported. In order to facilitate further improvements in performance the ability to quantitatively measure...

  3. Polarized tagged photons

    International Nuclear Information System (INIS)

    Maximon, L.C.; Ganz, Eric; Aniel, Thierry; Miniac, Arlette de.

    1982-03-01

    We consider in detail the differential cross section for polarized bremsstrahlung for angles and energies in the range of interest for a tagging system and derive a high energy, small angle approximation for this cross section. We use these approximations to determine the maxima and minima of the cross sections for these two polarization states, dσperpendicular and dσparallel, and to evaluate these cross sections at the extrema. It is shown that both dσperpendicular and dσparallel have a very sharp dip in the region of small momentum transfers. However, their behavior in the region of the dip, as a function of the azimuthal angle phi, is quite different over most of the photon spectrum. The cross section dσperpendicular behaves similarly to the cross section for unpolarized photons in that as phi increases, the sharp dip vanishes, the minimum fuses with the second maximum, and the cross section then has only a single maximum. In contrast, the sharp dip in the cross section dσparallel remains as phi increases. Coulomb corrections to the Born approximation are considered, and do not fill in these dips

  4. Photon compression in cylinders

    International Nuclear Information System (INIS)

    Ensley, D.L.

    1977-01-01

    It has been shown theoretically that intense microwave radiation is absorbed non-classically by a newly enunciated mechanism when interacting with hydrogen plasma. Fields > 1 Mg, lambda > 1 mm are within this regime. The predicted absorption, approximately P/sub rf/v/sub theta/sup e/, has not yet been experimentally confirmed. The applications of such a coupling are many. If microwave bursts approximately > 5 x 10 14 watts, 5 ns can be generated, the net generation of power from pellet fusion as well as various military applications becomes feasible. The purpose, then, for considering gas-gun photon compression is to obtain the above experimental capability by converting the gas kinetic energy directly into microwave form. Energies of >10 5 joules cm -2 and powers of >10 13 watts cm -2 are potentially available for photon interaction experiments using presently available technology. The following topics are discussed: microwave modes in a finite cylinder, injection, compression, switchout operation, and system performance parameter scaling

  5. Testgütekriterien des Fragebogens AnMS-Sport zur Erfassung des Anschlussmotivs im Sportkontext

    DEFF Research Database (Denmark)

    Elbe, Anne-Marie; Krippl, Martin; Melzer, Marcus

    2013-01-01

    , the questionnaire shows satisfactory Cronbach’s alpha. Construct validity is shown through correlations with two general questionnaires to measure the affiliation motive (Krippl, Itemanalytische Untersuchungen zur Selbstbeschreibung von Emotion und Motivation, 1999; Teubel, Eine deutsche Übersetzung der Mehrabian......In this paper the test control criteria of the sport-specific Affiliation Motives Scale-Sport are reported. Theoretical background for the development of the scale is the affiliation motive, which is composed of the two factors “hope for affiliation”and “fear of rejection” (Mehrabian and Ksionzkys...

  6. Heat recovery in sewage sludge gasification systems; Waermerueckgewinnung bei Anlagen zur Klaerschlammvergasung

    Energy Technology Data Exchange (ETDEWEB)

    Lamp, P.; Reichel, A.; Ziegler, F. [Bayerisches Zentrum fuer Angewandte Energieforschung e.V. (ZAE Bayern), Abt. Energieumwandlung und -speicherung, Garching (Germany)

    1996-12-31

    Using the example of a pilot plant for sewage sludge gasification by the Noell conversion process, the potential for energy optimisation is described. The goals of development are twofold: First, the process stages must be optimized so as to minimize energy consumption and secondly, all options for energy use and energy must be utilized. (orig) [Deutsch] Anhand einer Pilotanlage zur Klaerschlammvergasung nach dem NOELL-Konversionsverfahren sollen Moeglichkeiten der energetischen Optimierung beispielhaft aufgezeigt werden. Ziel muss es sein, zum einen die Verfahrensschritte auf einen moeglichst geringen Energiebedarf hin zu optimieren und zum anderen Moeglichkeiten der Waermeverschiebung und -rueckgewinnung soweit wie moeglich auszunutzen. (orig)

  7. Heat recovery in sewage sludge gasification systems; Waermerueckgewinnung bei Anlagen zur Klaerschlammvergasung

    Energy Technology Data Exchange (ETDEWEB)

    Lamp, P; Reichel, A; Ziegler, F [Bayerisches Zentrum fuer Angewandte Energieforschung e.V. (ZAE Bayern), Abt. Energieumwandlung und -speicherung, Garching (Germany)

    1997-12-31

    Using the example of a pilot plant for sewage sludge gasification by the Noell conversion process, the potential for energy optimisation is described. The goals of development are twofold: First, the process stages must be optimized so as to minimize energy consumption and secondly, all options for energy use and energy must be utilized. (orig) [Deutsch] Anhand einer Pilotanlage zur Klaerschlammvergasung nach dem NOELL-Konversionsverfahren sollen Moeglichkeiten der energetischen Optimierung beispielhaft aufgezeigt werden. Ziel muss es sein, zum einen die Verfahrensschritte auf einen moeglichst geringen Energiebedarf hin zu optimieren und zum anderen Moeglichkeiten der Waermeverschiebung und -rueckgewinnung soweit wie moeglich auszunutzen. (orig)

  8. Zur Interaktion von Genotyp und Ernährung bei Darmkrebs

    OpenAIRE

    Behrends, Thomas

    2013-01-01

    Ziel dieser Arbeit war es, sowohl die Auswirkungen einer veränderten Selenversorgung über die Nahrung als auch die Rolle des zentralen Transport- und Speicherproteins für Selen (Selenoprotein P, SepP) auf die intestinale Tumorigenese tierexperimentell zu untersuchen. Eine gestörte SepP-Expression, führte zur Ausbildung größerer Tumore. Durch eine Steigerung der Selenversorgung über die Nahrung eine signifikante Reduktion von Tumoranzahl und Gesamttumorfläche erzielt werden. Hierzu wurde den ...

  9. Anwendung stabiler Isotope zur Beschreibung des mikrobiellen Abbaus organischer Schadstoffe in kontaminierten Aquiferen

    OpenAIRE

    Vieth, Andrea

    2003-01-01

    Der mikrobielle in-situ Abbau organischer Schadstoffe ist mit einer Änderung der Isotopenverhältnisse (12C/13C; H/D) verbunden. Das Ausmaß der Isotopenfraktionierung ist abhängig von der initialen biochemischen Reaktion und variiert mit der Größe des Substratmoleküls bzw. der Anzahl der Kohlenstoff- bzw. Wasserstoffatome. Für die Anwendung dieses Isotopenkonzepts zur Beschreibung des mikrobiellen Abbaus von Schadstoffen im Grundwasser muss ausgeschlossen werden können, dass andere Prozesse ei...

  10. Digital announcements from data carrier exchange to telecommunication; Digitale Ausschreibungen; vom Datentraegeraustausch zur Telekommunikation

    Energy Technology Data Exchange (ETDEWEB)

    Markert, H. [MW Software GmbH, Koeln (Germany)

    1995-12-31

    In chapter 7 of the anthology about building control digital announcements are described ranging from data carrier exchange to telecommunication. The following aspects are discussed: Exchange of texts and prices as well of service lists and offers, telecommunication software, costs of communication, comparison of paper, disk and telecommunication. (BWI) [Deutsch] Kapitel 7 des Sammelbandes ueber Building Control ist dem Thema der digitalen Ausschreibung gewidmet, reichend vom Datentraegeraustausch zur Telekommunikation. In diesem Zusammenhang wird auf folgende Themen eingegangen: Austausch von Texten und Preisen sowie von Leistungsverzeichnissen und Angeboten; Telekommunikations-Software; Kosten der Kommunikation sowie Vergleich Papier - Diskette - Telekommunikation. (BWI)

  11. The step from the project control to long-distance control; Von der Projekt- zur Fernkontrolle

    Energy Technology Data Exchange (ETDEWEB)

    Kaelin, W. [Ingenieurbuero Werner Kaelin, Schwyz (Switzerland)

    1995-12-31

    In chapter 8 of the anthology about building control the extension from project control to long-distance control is described. The following aspects are discussed: guidelines (operating concept, task anthology), project (implementation, control, documentation), realisation (initiation, example), operation (regional co-operation, characteristic numbers). (BWI) [Deutsch] Kapitel 8 des Sammelbandes ueber Building Control ist dem Ausbau von der Projekt- zur Fernkontrolle gewidmet. In diesem Zusammenhang werden folgende Themen angesprochen: Vorgaben (Betriebskonzept, Pflichtenheft), Projekt (Umsetzung, Kontrolle, Dokumentation), Ausfuehrung (Inbetriebsetzung, Beispiel); Betrieb (regionaler Zusammenschluss, Kennzahlen). (BWI)

  12. Zusammenarbeit, Sichtbarkeit, Einbindung und Effizienz : Fallstudie zur Verwendung interaktiver Whiteboards an einem Gymnasium in Deutschland

    OpenAIRE

    Passey, Donald

    2017-01-01

    Dieser Bericht bietet einen Überblick über die Ergebnisse einer einjährigen Studie, die an einer deutschen Schule (Gymnasium) in einer Stadt in Nordrhein-Westfalen (NRW) durchgeführt wurde. Während ein Forschungsschwerpunkt auf dem Thema „Zusammenarbeit“ lag, erforderte auch die Planung und Durchführung der Studie gemeinsame Anstrengungen: Die Schule hatte ihren Anteil an der Implementation interaktiver Whiteboards; SMART Technologies stellte Ausrüstung und technische Unterstützung zur Verfüg...

  13. Die muslimische Gemeinschaft Rumäniens: der Weg einer Elite zur marginalisierten Minderheit

    OpenAIRE

    Kahl, Thede

    2005-01-01

    Die Siedlungsgeschichte der Muslime auf dem Territorium des heutigen Rumäniens geht in das 13. Jahrhundert zurück. Durch verstärkte Einwanderung von Turkmenen und Tataren konnten sich im Laufe der folgenden Jahrhunderte Regionen mit muslimischer kultureller Dominanz ausbilden. Aufgrund der Kolonisierungspolitik der osmanischen Sultane im Laufe des 14.-16. Jahrhunderts erhöhte sich Zahl der Muslime ständig, da sie sowohl aus dem Norden des Schwarzen Meeres als auch aus dem Süden (Kleinasien) Z...

  14. Sprechkompetenz im DaF-Unterricht an Slowenischen Gymnasien: von der Theorie zur Praxis

    Directory of Open Access Journals (Sweden)

    Andreja Retelj

    2016-12-01

    Full Text Available Es liegt auf der Hand, dass Fremdsprachenkenntnisse aufgrund der wachsenden Globalisierung stets an Bedeutung gewinnen. Über eine hochentwickelte Fremdsprachenkompetenz zu verfügen, ist in der heutigen Gesellschaft fast zur Selbstverständlichkeit geworden. Durch die wachsenden wirtschaftlichen Kontakte gewinnt vor allem die mündliche Kommunikation immer mehr an Bedeutung und die Erwartungen an Fremdsprachenlernende, in verschiedenen Sprachsituationen mündlich schnell und angemessen kommunizieren zu können, nehmen aus diesem Grund ständig zu.

  15. Robust Adaptive Photon Tracing using Photon Path Visibility

    DEFF Research Database (Denmark)

    Hachisuka, Toshiya; Jensen, Henrik Wann

    2011-01-01

    We present a new adaptive photon tracing algorithm which can handle illumination settings that are considered difficult for photon tracing approaches such as outdoor scenes, close-ups of a small part of an illuminated region, and illumination coming through a small gap. The key contribution in our...... algorithm is the use of visibility of photon path as the importance function which ensures that our sampling algorithm focuses on paths that are visible from the given viewpoint. Our sampling algorithm builds on two recent developments in Markov chain Monte Carlo methods: adaptive Markov chain sampling...... and replica exchange. Using these techniques, each photon path is adaptively mutated and it explores the sampling space efficiently without being stuck at a local peak of the importance function. We have implemented this sampling approach in the progressive photon mapping algorithm which provides visibility...

  16. Modification of equivalent photon approximation (EPA) for resolved photon processes

    International Nuclear Information System (INIS)

    Drees, M.; Godbole, R.M.

    1995-05-01

    The authors propose a modification of the equivalent photon approximation (EPA) for processes which involve the parton content of the photon, to take into account the suppression of the photonic parton fluxes due to the virtuality of the photon. They present simple, physically motivated ansaetze to model this suppression and show that even though the parton content of the electron no longer factorizes into an electron flux function and photon structure function, it is still possible to express it as a single integral. They also show that for the TRISTAN (transposable ring intersecting storage accelerators in Nippon) experiments its effects can be numerically of the same size as that of the NLO corrections. Further, it is discussed a possible measurements at HERA (hadron electron ring an large), which can be provide an experimental handle on the effect the authors model through their ansaetze

  17. Amplified Photon Upconversion by Photonic Shell of Cholesteric Liquid Crystals.

    Science.gov (United States)

    Kang, Ji-Hwan; Kim, Shin-Hyun; Fernandez-Nieves, Alberto; Reichmanis, Elsa

    2017-04-26

    As an effective platform to exploit triplet-triplet-annihilation-based photon upconversion (TTA-UC), microcapsules composed of a fluidic UC core and photonic shell are microfluidically prepared using a triple emulsion as the template. The photonic shell consists of cholesteric liquid crystals (CLCs) with a periodic helical structure, exhibiting a photonic band gap. Combined with planar anchoring at the boundaries, the shell serves as a resonance cavity for TTA-UC emission and enables spectral tuning of the UC under low-power-density excitation. The CLC shell can be stabilized by introducing a polymerizable mesogen in the LC host. Because of the microcapsule spherical symmetry, spontaneous emission of the delayed fluorescence is omnidirectionally amplified at the edge of the stop band. These results demonstrate the range of opportunities provided by TTA-UC systems for the future design of low-threshold photonic devices.

  18. Photonic integration and photonics-electronics convergence on silicon platform

    CERN Document Server

    Liu, Jifeng; Baba, Toshihiko; Vivien, Laurent; Xu, Dan-Xia

    2015-01-01

    Silicon photonics technology, which has the DNA of silicon electronics technology, promises to provide a compact photonic integration platform with high integration density, mass-producibility, and excellent cost performance. This technology has been used to develop and to integrate various photonic functions on silicon substrate. Moreover, photonics-electronics convergence based on silicon substrate is now being pursued. Thanks to these features, silicon photonics will have the potential to be a superior technology used in the construction of energy-efficient cost-effective apparatuses for various applications, such as communications, information processing, and sensing. Considering the material characteristics of silicon and difficulties in microfabrication technology, however, silicon by itself is not necessarily an ideal material. For example, silicon is not suitable for light emitting devices because it is an indirect transition material. The resolution and dynamic range of silicon-based interference de...

  19. Enantioselektivität und Isotopendiskriminierung - Zur Analytik von 1,2-Propandiol und 4-Hydroxy-2,5-dimethyl-3(2H)-furanon (Furaneol)

    OpenAIRE

    Hartlieb, Ariane

    2009-01-01

    Aussagekräftige Methoden zur Authentizitätsbewertung sind unerlässlich, um so-wohl einen fairen Handel als auch das Vertrauen der Verbraucher in die Qualität von Lebensmitteln zu gewährleisten. Das Ziel dieser Arbeit war es, anhand der Parameter 'Enantioselektivität' und 'Iso-topendiskriminierung' Methoden zur Authentizitätskontrolle von Schaumweinen und Erdbeeren, beides Produkte mit einem vergleichsweise hohen Handelswert, zur Verfügung zu stellen. Um unmittelbare Anwendbarkeit in der Praxi...

  20. Uses of continuous measuring techniques for optimizing the operation of municipal sewage treatment plants; Einsatzmoeglichkeiten kontinuierlicher Messtechnik zur Betriebsoptimierung kommunaler Klaeranlagen

    Energy Technology Data Exchange (ETDEWEB)

    Wedi, D [Vermicon AG, Muenchen/Braunschweig (Germany)

    1998-12-31

    Three different optimization measures are briefly discussed, each of which was carried out with the support of continuous measurements: efforts to enhance the sedimentation performance of a final sedimentation tank, investigations to establish the nitrification performance of an existing plant, and measurements permitting optimized parametrization of the complex control of a new sewage treatement plant. (orig./SR) [Deutsch] Es werden drei verschiedene Optimierungsmassnahmen kurz erlaeutert, die jeweils mit Unterstutzung kontinuierlicher Messungen erfolgten: Arbeiten zur Verbesserung der Sedimentationsleistung eines Nachklaerbeckens, Untersuchungen zur besseren Nachrechnung der Nitrifikationskapazitaet einer bestehenden Anlage und Messungen zur optimierten Parametrierung einer komplexeren Regelung einer neuen Klaeranlage. (orig./SR)

  1. Medien – Generationen – Wissen. Überlegungen zur medienpädagogischen Forschung – dargestellt am Beispiel der Frage nach dem Weltwissen globaler Mediengenerationen

    Directory of Open Access Journals (Sweden)

    Theo Hug

    2017-07-01

    Full Text Available Mit den aktuellen gesellschaftlichen, technologischen und politischen Entwicklungen haben sich neue Fragen und Aufgabenbereiche für die Medienpädagogik ergeben. Diese werden im vorliegenden Beitrag skizziert, wobei in Abgrenzung von traditionellen Auffassungen für ein weiteres Verständnis von Medienpädagogik argumentiert wird. Die Erweiterung des thematischen Horizonts wird anhand einer Pilotstudie zur Frage des Weltwissens von Mediengenerationen exemplarisch verdeutlicht. Abschließend werden einige Überlegungen zur Medienkompetenz, der Problematik diesbezüglicher Verkürzungen und deren Stellenwert im Lichte des „medial turn“ zur Diskussion gestellt.

  2. Uses of continuous measuring techniques for optimizing the operation of municipal sewage treatment plants; Einsatzmoeglichkeiten kontinuierlicher Messtechnik zur Betriebsoptimierung kommunaler Klaeranlagen

    Energy Technology Data Exchange (ETDEWEB)

    Wedi, D. [Vermicon AG, Muenchen/Braunschweig (Germany)

    1997-12-31

    Three different optimization measures are briefly discussed, each of which was carried out with the support of continuous measurements: efforts to enhance the sedimentation performance of a final sedimentation tank, investigations to establish the nitrification performance of an existing plant, and measurements permitting optimized parametrization of the complex control of a new sewage treatement plant. (orig./SR) [Deutsch] Es werden drei verschiedene Optimierungsmassnahmen kurz erlaeutert, die jeweils mit Unterstutzung kontinuierlicher Messungen erfolgten: Arbeiten zur Verbesserung der Sedimentationsleistung eines Nachklaerbeckens, Untersuchungen zur besseren Nachrechnung der Nitrifikationskapazitaet einer bestehenden Anlage und Messungen zur optimierten Parametrierung einer komplexeren Regelung einer neuen Klaeranlage. (orig./SR)

  3. Topological Order in Silicon Photonics

    Science.gov (United States)

    2017-02-07

    photonic edge states and quantum emitters [ S. Barik , H. Miyake, W. DeGottardi, E. Waks and M. Hafezi, New J. Phys., 18, 11301 (2016) ]. Entanglement... Barik , H. Miyake, W. DeGottardi, E. Waks, and M. Hafezi “Two-Dimensionally Confined Topological Edge States in Photonic Crystals”, New J. Phys., 18

  4. Photonic nanowires for quantum optics

    DEFF Research Database (Denmark)

    Munsch, M.; Claudon, J.; Bleuse, J.

    Photonic nanowires (PWs) are simple dielectric structures for which a very efficient and broadband spontaneous emission (SE) control has been predicted [1]. Recently, a single photon source featuring a record high efficiency was demonstrated using this geometry [2]. Using time-resolved micro-phot...

  5. XCOM: Photon Cross Sections Database

    Science.gov (United States)

    SRD 8 XCOM: Photon Cross Sections Database (Web, free access)   A web database is provided which can be used to calculate photon cross sections for scattering, photoelectric absorption and pair production, as well as total attenuation coefficients, for any element, compound or mixture (Z <= 100) at energies from 1 keV to 100 GeV.

  6. Photonic-crystal fibers gyroscope

    Directory of Open Access Journals (Sweden)

    Ali Muse Haider

    2015-01-01

    Full Text Available In this paper we proposed to use of a photonic crystal fiber with an inner hollow defect. The use of such fibers is not affected by a material medium on the propagation of optical radiation. Photonic crystal fibers present special properties and capabilities that lead to an outstanding potential for sensing applications

  7. Experimental test of magnetic photons

    International Nuclear Information System (INIS)

    Lakes, R.S.

    2004-01-01

    A 'magnetic' photon hypothesis associated with magnetic monopoles is tested experimentally. These photons are predicted to easily penetrate metal. Experimentally the optical transmittance T of a metal foil was less than 2x10-17. The hypothesis is not supported since it predicts T=2x10-12

  8. Advances on integrated microwave photonics

    DEFF Research Database (Denmark)

    Dong, Jianji; Liao, Shasha; Yan, Siqi

    2017-01-01

    Integrated microwave photonics has attracted a lot of attentions and makes significant improvement in last 10 years. We have proposed and demonstrated several schemes about microwave photonics including waveform generation, signal processing and energy-efficient micro-heaters. Our schemes are all...

  9. The STAR Photon Multiplicity Detector

    Energy Technology Data Exchange (ETDEWEB)

    Aggarwal, M.M.; Badyal, S.K.; Bhaskar, P.; Bhatia, V.S.; Chattopadhyay, S. E-mail: sub@veccal.ernet.in; Das, S.; Datta, R.; Dubey, A.K.; Dutta Majumdar, M.R.; Ganti, M.S.; Ghosh, P.; Gupta, A.; Gupta, M.; Gupta, R.; Kaur, I.; Kumar, A.; Mahajan, S.; Mahapatra, D.P.; Mangotra, L.K.; Mishra, D.; Mohanty, B.; Nayak, S.K.; Nayak, T.K.; Pal, S.K.; Phatak, S.C.; Potukuchi, B.V.K.S.; Raniwala, R.; Raniwala, S.; Sahoo, R.; Sharma, A.; Singaraju, R.N.; Sood, G.; Trivedi, M.D.; Varma, R.; Viyogi, Y.P

    2003-03-01

    Details concerning the design, fabrication and performance of STAR Photon Multiplicity Detector (PMD) are presented. The PMD will cover the forward region, within the pseudorapidity range 2.3-3.5, behind the forward time projection chamber. It will measure the spatial distribution of photons in order to study collective flow, fluctuation and chiral symmetry restoration.

  10. Photonic Free-Electron Lasers

    NARCIS (Netherlands)

    van der Slot, Petrus J.M.; Denis, T.; Lee, J.H.H.; van Dijk, M.W.; Boller, Klaus J.

    2012-01-01

    A photonic free-electron laser (pFEL) produces coherent Cerenkov radiation from a set of parallel electron beams streaming through a photonic crystal. The function of the crystal is to slow down the phase velocity of a copropagating electromagnetic wave, such that also mildly relativistic electrons

  11. Nanodiamond particles forming photonic structures

    International Nuclear Information System (INIS)

    Grichko, Varvara; Tyler, Talmage; Grishko, Victor I; Shenderova, Olga

    2008-01-01

    Colloid suspensions of irregularly shaped, highly charged detonation nanodiamond particles are found to have unexpected optical properties, similar to those of photonic crystals. This finding is all the more surprising since the particles used in this work are far more polydisperse than those typically forming photonic crystals. Intensely iridescent structures have been fabricated using the centrifugation of aqueous suspensions of nanodiamonds

  12. Nanodiamond particles forming photonic structures

    Energy Technology Data Exchange (ETDEWEB)

    Grichko, Varvara; Tyler, Talmage; Grishko, Victor I; Shenderova, Olga [International Technology Center, 8100 Brownleigh Drive, Suite 120, Raleigh, NC 27617 (United States)], E-mail: oshenderova@itc-inc.org

    2008-06-04

    Colloid suspensions of irregularly shaped, highly charged detonation nanodiamond particles are found to have unexpected optical properties, similar to those of photonic crystals. This finding is all the more surprising since the particles used in this work are far more polydisperse than those typically forming photonic crystals. Intensely iridescent structures have been fabricated using the centrifugation of aqueous suspensions of nanodiamonds.

  13. Silicon photonics fundamentals and devices

    CERN Document Server

    Deen, M Jamal

    2012-01-01

    The creation of affordable high speed optical communications using standard semiconductor manufacturing technology is a principal aim of silicon photonics research. This would involve replacing copper connections with optical fibres or waveguides, and electrons with photons. With applications such as telecommunications and information processing, light detection, spectroscopy, holography and robotics, silicon photonics has the potential to revolutionise electronic-only systems. Providing an overview of the physics, technology and device operation of photonic devices using exclusively silicon and related alloys, the book includes: * Basic Properties of Silicon * Quantum Wells, Wires, Dots and Superlattices * Absorption Processes in Semiconductors * Light Emitters in Silicon * Photodetectors , Photodiodes and Phototransistors * Raman Lasers including Raman Scattering * Guided Lightwaves * Planar Waveguide Devices * Fabrication Techniques and Material Systems Silicon Photonics: Fundamentals and Devices outlines ...

  14. Two-dimensional topological photonics

    Science.gov (United States)

    Khanikaev, Alexander B.; Shvets, Gennady

    2017-12-01

    Originating from the studies of two-dimensional condensed-matter states, the concept of topological order has recently been expanded to other fields of physics and engineering, particularly optics and photonics. Topological photonic structures have already overturned some of the traditional views on wave propagation and manipulation. The application of topological concepts to guided wave propagation has enabled novel photonic devices, such as reflection-free sharply bent waveguides, robust delay lines, spin-polarized switches and non-reciprocal devices. Discrete degrees of freedom, widely used in condensed-matter physics, such as spin and valley, are now entering the realm of photonics. In this Review, we summarize the latest advances in this highly dynamic field, with special emphasis on the experimental work on two-dimensional photonic topological structures.

  15. Photon Entanglement Through Brain Tissue.

    Science.gov (United States)

    Shi, Lingyan; Galvez, Enrique J; Alfano, Robert R

    2016-12-20

    Photon entanglement, the cornerstone of quantum correlations, provides a level of coherence that is not present in classical correlations. Harnessing it by study of its passage through organic matter may offer new possibilities for medical diagnosis technique. In this work, we study the preservation of photon entanglement in polarization, created by spontaneous parametric down-conversion, after one entangled photon propagates through multiphoton-scattering brain tissue slices with different thickness. The Tangle-Entropy (TS) plots show the strong preservation of entanglement of photons propagating in brain tissue. By spatially filtering the ballistic scattering of an entangled photon, we find that its polarization entanglement is preserved and non-locally correlated with its twin in the TS plots. The degree of entanglement correlates better with structure and water content than with sample thickness.

  16. Von neuen Geschäftsideen zur gelebten Digitalisierung in Utility 4.0 - das Integrierte Geschäftsmodell

    Science.gov (United States)

    Doleski, Oliver D.

    Die Energiewirtschaft benötigt neue, digitale Geschäftsmodelle. Gegenwärtig folgt auf Liberalisierung und Energiewende die nächste Stufe einer weitreichenden Bereinigung des Versorgungsmarktes. Digitalisierung und Dezentralisierung sind heute in aller Munde und verlangen nach neuen Produkten und Dienstleistungen. Dabei wirken die immensen Herausforderungen einer digitalen Energiewelt wie Beschleuniger für die Transformation im Versorgungssektor und tragen damit zur breiten Etablierung von Utilities 4.0 bei. Dieser Entwicklungsprozess vollzieht sich mithilfe unterschiedlicher Methoden zur Realisierung neuer Geschäftsideen. Allerdings greifen die gängigen Konzepte zur Entwicklung von Geschäftsmodellen gerade im Hinblick auf die Berücksichtigung komplexer, unbeständiger Rahmenbedingungen und spezifischer Anforderungen der digitalen Energiewelt mitunter zu kurz. Vor diesem Hintergrund wird das auf dem ganzheitlichen St. Galler Management-Konzept beruhende Integrierte Geschäftsmodell iOcTen als geeignetes Instrumentarium zur Geschäftsmodellentwicklung vorgestellt. Neben der Modellbeschreibung unterstützt ein intuitiv verständlicher Leitfaden den Praktiker bei der Transformation vom klassischen Versorgungsunternehmen zum digitalen Energiedienstleistungsunternehmen.

  17. [Heinz von zur Mühlen. Das Bürgertum Fordert Blut. Ein Bolschewistiches Flugblatt von 1918] / Paul Kaegbein

    Index Scriptorium Estoniae

    Kaegbein, Paul

    2007-01-01

    Arvustus: Heinz von zur Mühlen. Das Bürgertum Fordert Blut. Ein Bolschewistiches Flugblatt von 1918. In : Ostseeprovinzen, baltische Staaten und das Nationale. Münster : LIT, 2005, lk. 403-414. 1918. aastast pärit lendlehest, mille käekirja järgi otsustades on kirjutanud Viktor Kingissepp

  18. [Heinz von zur Mühlen. Paul Johansen und die Sogenannten Undeutschen in Reval/Tallinn] / Paul Kaegbein

    Index Scriptorium Estoniae

    Kaegbein, Paul

    2008-01-01

    Arvustus: Heinz von zur Mühlen. Paul Johansen und die Sogenannten Undeutschen in Reval/Tallinn. - Nordosteuropa als Geschichtsregion. Helsinki : Aue-Stiftung :; Lübeck : Schmidt-Römhild, 2006. lk. 103-111. Paul Johanseni lähim töökaaslane kirjeldab teose "Deutsch und Undeutsch im mittelalterlichen und frühneuzeitlichen Reval" valmimist

  19. Photonics principles and practices

    CERN Document Server

    Al-Azzawi, Abdul

    2006-01-01

    Light The Nature of Light Light and Shadows Thermal Radiation Light Production Light Intensity Light and Colour Laws of Light Optics Plane Mirrors Spherical Mirrors Lenses Prisms Beamsplitters Light Passing through Optical Components Optical Instruments for Viewing Applications Polarization of Light Optical Materials Waves and Diffraction Waves Interference and Diffraction The Diffraction Grating Interferometers Spectrometers and Spectroscopes Optical Fibres Fibre Optic Cables Advanced Fibre Optic Cables Light Attenuation in Optical Components Fibre-Optic Cable Types and Installations Fibre-Optic Connectors Passive Fibre Optic Devices Wavelength Division Multiplexer Optical Amplifiers Optical Receivers Lasers Optical Switches Optical Fibre Communications Fibre Optic Lighting Testing Fibre Optic Testing Safety Photonics Laboratory Safety Miscellaneous Appendix A: Details of the Devices, Components, Tools, and Parts Appendix B: Alignment Procedure of a Conventional Ar...

  20. Photonics a short course

    CERN Document Server

    Degiorgio, Vittorio

    2016-01-01

    This extended and revised edition will serve as a concise, self-contained, up-to-date introduction to Photonics for undergraduate students. It can also be used as a primer by researchers and professionals who start working in the field. Blending theory with technical descriptions, the book covers a wide range of topics, including the general mechanism of laser action, continuous and pulsed laser operation, optical propagation in isotropic and anisotropic media, operating principles and structure of passive optical components, electro-optic and acousto-optic modulation, solid-state lasers, semiconductor lasers and LEDs, nonlinear optical phenomena, and optical fiber components and devices. The book concludes with an overview of applications, including optical communications, telemetry and sensing, industrial and biomedical applications, solid-state lighting, displays, and photovoltaics. This second edition includes a set of problems at the end of all but the last chapter. These problems deal with numerical c...

  1. Photon enhanced thermionic emission

    Science.gov (United States)

    Schwede, Jared; Melosh, Nicholas; Shen, Zhixun

    2014-10-07

    Photon Enhanced Thermionic Emission (PETE) is exploited to provide improved efficiency for radiant energy conversion. A hot (greater than 200.degree. C.) semiconductor cathode is illuminated such that it emits electrons. Because the cathode is hot, significantly more electrons are emitted than would be emitted from a room temperature (or colder) cathode under the same illumination conditions. As a result of this increased electron emission, the energy conversion efficiency can be significantly increased relative to a conventional photovoltaic device. In PETE, the cathode electrons can be (and typically are) thermalized with respect to the cathode. As a result, PETE does not rely on emission of non-thermalized electrons, and is significantly easier to implement than hot-carrier emission approaches.

  2. Progress on photonic crystals

    CERN Document Server

    Lecoq, P; Gundacker, S; Hillemanns, H; Jarron, P; Knapitsch, A; Leclercq, J L; Letartre, X; Meyer, T; Pauwels, K; Powolny, F; Seassal, C

    2010-01-01

    The renewal of interest for Time of Flight Positron Emission Tomography (TOF PET) has highlighted the need for increasing the light output of scintillating crystals and in particular for improving the light extraction from materials with a high index of refraction. One possible solution to overcome the problem of total internal reflection and light losses resulting from multiple bouncing within the crystal is to improve the light extraction efficiency at the crystal/photodetector interface by means of photonic crystals, i.e. media with a periodic modulation of the dielectric constant at the wavelength scale. After a short reminder of the underlying principles this contribution proposes to present the very encouraging results we have recently obtained on LYSO pixels and the perspectives on other crystals such as BGO, LuYAP and LuAG. These results confirm the impressive predictions from our previously published Monte Carlo simulations. A detailed description of the sample preparation procedure is given as well ...

  3. Photonics a short course

    CERN Document Server

    Degiorgio, Vittorio

    2014-01-01

    This book will serve as a concise, self-contained, up-to-date introduction to Photonics, to be used as a textbook for undergraduate students or as a reference book for researchers and professionals. Blending theory with technical descriptions, the book covers a wide range of topics, including the general mechanism of laser action, continuous and pulsed laser operation, optical propagation in isotropic and anisotropic media, operating principles and structure of passive optical components, electro-optical and acousto-optical modulation, solid-state lasers, semiconductor lasers and LEDs, nonlinear optics, and optical fiber components and devices.. The book concludes with an overview of applications, including optical communications, telemetry and sensing, industrial and biomedical applications, solid-state lighting, displays, and photovoltaics.

  4. Ordered photonic microstructures

    Science.gov (United States)

    Chen, Kevin Ming

    2001-09-01

    This thesis examines novel photonic materials systems possessing order in the atomic, microscopic, and macroscopic dimensional regimes. In the atomic order regime, a structure-property investigation is done for Er2O3 in which the first report of room temperature photoluminescence (PL) is provided. Thin films of the rare earth oxide were deposited via reactive sputtering of Er metal in an Ar/O2 ambient, and subsequently annealed to promote grain growth. Heat treatment consisting of a 650°C followed by 1000°C anneal produces maximum crystallinity as measured by glancing angle x-ray diffraction. These films show characteristic PL at λ = 1.54 μm. In the microscopic order regime, omnidirectional reflectors and thin film microcavities are demonstrated using sol-gel and solid-state materials. A first demonstration of omnidirectional reflectivity in sol-gel structures was accomplished using a dielectric stack consisting of 12 spin-on SiO 2/TiO2 quarterwave sol-gel films. Similarly, solid-state dielectric stacks consisting of 6 Si/SiO2 sputtered films were used to demonstrate the same principle. Microcavities were formed using solgel structures, producing a low quality factor Q = 35 due to limitations in film thickness control and lossy interfaces from stress-induced cracks. The high index contrast Si/SiO2 microcavities enabled Q ~ 1000 using 17 total layers following hydrogenation of dangling bonds within the amorphous Si films. Combining fabrication processes for the solid-state microcavity and Er2O3 films, a device was fabricated to demonstrate photoluminescence enhancement of an Er2O3 film embedded in a microcavity. The structure consisted of 3-bilayer mirrors on either side of an SiO2/Er2O3/SiO2 cavity. The Q ~ 300 was near the theoretical value for such a structure. At room temperature, PL of Er2O3 was enhanced by a factor of 1000 in the microcavity compared to a single thin film. In the macroscopic order regime, self-assembly of micron- sized SiO 2 and

  5. The advanced photon source

    International Nuclear Information System (INIS)

    Galayda, J.N.

    1995-01-01

    The Advanced Photon Source (APS) is a 7-GeV third-generation synchrotron radiation storage ring and full-energy positron injector. Construction project funding began in 1989, and ground breaking took place on 5 May 1990. Construction of all accelerator facilities was completed in January 1995 and storage ring commissioning is underway. First observation of x-rays from a bending magnet source took place on 26 March 1995. Nearly all performance specifications of the injector have been reached, and first observations indicate that the reliability, dynamic aperture, emittance, and orbit stability in the storage ring are satisfactory. Observation of radiation from the first of 20 insertion device beamlines is scheduled for October 1995. Start of regular operations is expected to take place well before the APS Project target date of December 1996

  6. Photonic quantum information: science and technology.

    Science.gov (United States)

    Takeuchi, Shigeki

    2016-01-01

    Recent technological progress in the generation, manipulation and detection of individual single photons has opened a new scientific field of photonic quantum information. This progress includes the realization of single photon switches, photonic quantum circuits with specific functions, and the application of novel photonic states to novel optical metrology beyond the limits of standard optics. In this review article, the recent developments and current status of photonic quantum information technology are overviewed based on the author's past and recent works.

  7. Spatial photon correlations in multiple scattering media

    DEFF Research Database (Denmark)

    Smolka, Stephan; Muskens, O.; Lagendijk, A.

    2010-01-01

    We present the first angle-resolved measurements of spatial photon correlations that are induced by multiple scattering of light. The correlation relates multiple scattered photons at different spatial positions and depends on incident photon fluctuations.......We present the first angle-resolved measurements of spatial photon correlations that are induced by multiple scattering of light. The correlation relates multiple scattered photons at different spatial positions and depends on incident photon fluctuations....

  8. Nonlocal hyperconcentration on entangled photons using photonic module system

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Cong; Wang, Tie-Jun; Mi, Si-Chen [School of Science, Beijing University of Posts and Telecommunications, Beijing 100876 (China); State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications, Beijing 100876 (China); Zhang, Ru [School of Science, Beijing University of Posts and Telecommunications, Beijing 100876 (China); State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications, Beijing 100876 (China); School of Ethnic Minority Education, Beijing University of Posts and Telecommunications, Beijing 100876 (China); Wang, Chuan, E-mail: wangchuan@bupt.edu.cn [School of Science, Beijing University of Posts and Telecommunications, Beijing 100876 (China); State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications, Beijing 100876 (China)

    2016-06-15

    Entanglement distribution will inevitably be affected by the channel and environment noise. Thus distillation of maximal entanglement nonlocally becomes a crucial goal in quantum information. Here we illustrate that maximal hyperentanglement on nonlocal photons could be distilled using the photonic module and cavity quantum electrodynamics, where the photons are simultaneously entangled in polarization and spatial-mode degrees of freedom. The construction of the photonic module in a photonic band-gap structure is presented, and the operation of the module is utilized to implement the photonic nondestructive parity checks on the two degrees of freedom. We first propose a hyperconcentration protocol using two identical partially hyperentangled initial states with unknown coefficients to distill a maximally hyperentangled state probabilistically, and further propose a protocol by the assistance of an ancillary single photon prepared according to the known coefficients of the initial state. In the two protocols, the total success probability can be improved greatly by introducing the iteration mechanism, and only one of the remote parties is required to perform the parity checks in each round of iteration. Estimates on the system requirements and recent experimental results indicate that our proposal is realizable with existing or near-further technologies.

  9. Photon technology. Laser processing technology; Photon technology. Laser process gijutsu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-03-01

    Survey has been conducted to develop laser processing technology utilizing the interaction between substance and photon. This is a part of the leading research on photon technology development. The photon technology development is aimed at novel technology development highly utilizing the quantum nature of photons. In the field of laser processing, high quality photons are used as tools, special functions of atoms and molecules will be discovered, and processing for functional fabrication (photon machining) will be established. A role of laser processing in industries has become significant, which is currently spreading not only into cutting and welding of materials and scalpels but also into such a special field as ultrafine processing of materials. The spreading is sometimes obstructed due to the difficulty of procurement of suitable machines and materials, and the increase of cost. The purpose of this study is to develop the optimal laser technology, to elucidate the interaction between substance and photon, and to develop the laser system and the transmission and regulation systems which realize the optimal conditions. 387 refs., 115 figs., 25 tabs.

  10. Nonlocal hyperconcentration on entangled photons using photonic module system

    International Nuclear Information System (INIS)

    Cao, Cong; Wang, Tie-Jun; Mi, Si-Chen; Zhang, Ru; Wang, Chuan

    2016-01-01

    Entanglement distribution will inevitably be affected by the channel and environment noise. Thus distillation of maximal entanglement nonlocally becomes a crucial goal in quantum information. Here we illustrate that maximal hyperentanglement on nonlocal photons could be distilled using the photonic module and cavity quantum electrodynamics, where the photons are simultaneously entangled in polarization and spatial-mode degrees of freedom. The construction of the photonic module in a photonic band-gap structure is presented, and the operation of the module is utilized to implement the photonic nondestructive parity checks on the two degrees of freedom. We first propose a hyperconcentration protocol using two identical partially hyperentangled initial states with unknown coefficients to distill a maximally hyperentangled state probabilistically, and further propose a protocol by the assistance of an ancillary single photon prepared according to the known coefficients of the initial state. In the two protocols, the total success probability can be improved greatly by introducing the iteration mechanism, and only one of the remote parties is required to perform the parity checks in each round of iteration. Estimates on the system requirements and recent experimental results indicate that our proposal is realizable with existing or near-further technologies.

  11. Identifikationsverfahren zur Analyse von EEG-Signalen bei Epilepsie mit Reaktions-Diffusions Netzwerken

    Science.gov (United States)

    Gollas, F.; Tetzlaff, R.

    2007-06-01

    Partielle Differentialgleichungen des Reaktions-Diffusions-Typs beschreiben Phänomene wie Musterbildung, nichtlineare Wellenausbreitung und deterministisches Chaos und werden oft zur Untersuchung komplexer Vorgänge auf den Gebieten der Biologie, Chemie und Physik herangezogen. Zellulare Nichtlineare Netzwerke (CNN) sind eine räumliche Anordnung vergleichsweise einfacher dynamischer Systeme, die eine lokale Kopplung untereinander aufweisen. Durch eine Diskretisierung der Ortsvariablen können Reaktions-Diffusions-Gleichungen häufig auf CNN mit nichtlinearen Gewichtsfunktionen abgebildet werden. Die resultierenden Reaktions-Diffusions-CNN (RD-CNN) weisen dann in ihrer Dynamik näherungsweise gleiches Verhalten wie die zugrunde gelegten Reaktions-Diffusions-Systeme auf. Werden RD-CNN zur Identifikation neuronaler Strukturen anhand von EEG-Signalen herangezogen, so besteht die Möglichkeit festzustellen, ob das gefundene Netzwerk lokale Aktivität aufweist. Die von Chua eingeführte Theorie der lokalen Aktivität Chua (1998); Dogaru und Chua (1998) liefert eine notwendige Bedingung für das Auftreten von emergentem Verhalten in zellularen Netzwerken. Änderungen in den Parametern bestimmter RD-CNN könnten auf bevorstehende epileptische Anfälle hinweisen. In diesem Beitrag steht die Identifikation neuronaler Strukturen anhand von EEG-Signalen durch Reaktions-Diffusions-Netzwerke im Vordergrund der dargestellten Untersuchungen. In der Ergebnisdiskussion wird insbesondere auch die Frage nach einer geeigneten Netzwerkstruktur mit minimaler Komplexität behandelt.

  12. Multi-Photon Entanglement and Quantum Teleportation

    National Research Council Canada - National Science Library

    Shih, Yanhua

    1999-01-01

    The project 'Multi-Photon Entanglement and Quantum Teleportation' concerns a series of experimental and theoretical investigations on multi-photon entangled states and the applications, for example...

  13. Holographic Two-Photon Induced Photopolymerization

    Data.gov (United States)

    Federal Laboratory Consortium — Holographic two-photon-induced photopolymerization (HTPIP) offers distinct advantages over conventional one-photon-induced photopolymerization and current techniques...

  14. Photonic crystals, amorphous materials, and quasicrystals.

    Science.gov (United States)

    Edagawa, Keiichi

    2014-06-01

    Photonic crystals consist of artificial periodic structures of dielectrics, which have attracted much attention because of their wide range of potential applications in the field of optics. We may also fabricate artificial amorphous or quasicrystalline structures of dielectrics, i.e. photonic amorphous materials or photonic quasicrystals. So far, both theoretical and experimental studies have been conducted to reveal the characteristic features of their optical properties, as compared with those of conventional photonic crystals. In this article, we review these studies and discuss various aspects of photonic amorphous materials and photonic quasicrystals, including photonic band gap formation, light propagation properties, and characteristic photonic states.

  15. Analysis of photonic band gap in novel piezoelectric photonic crystal

    Science.gov (United States)

    Malar Kodi, A.; Doni Pon, V.; Joseph Wilson, K. S.

    2018-03-01

    The transmission properties of one-dimensional novel photonic crystal having silver-doped novel piezoelectric superlattice and air as the two constituent layers have been investigated by means of transfer matrix method. By changing the appropriate thickness of the layers and filling factor of nanocomposite system, the variation in the photonic band gap can be studied. It is found that the photonic band gap increases with the filling factor of the metal nanocomposite and with the thickness of the layer. These structures possess unique characteristics enabling one to operate as optical waveguides, selective filters, optical switches, integrated piezoelectric microactuators, etc.

  16. Photonic Paint Developed with Metallic Three-Dimensional Photonic Crystals

    Science.gov (United States)

    Sun, Po; Williams, John D.

    2012-01-01

    This work details the design and simulation of an inconspicuous photonic paint that can be applied onto an object for anticounterfeit and tag, track, and locate (TTL) applications. The paint consists of three-dimensional metallic tilted woodpile photonic crystals embedded into a visible and infrared transparent polymer film, which can be applied to almost any surface. The tilted woodpile photonic crystals are designed with a specific pass band detectable at nearly all incident angles of light. When painted onto a surface, these crystals provide a unique reflective infra-red optical signature that can be easily observed and recorded to verify the location or contents of a package.

  17. Vertebroplasty in the treatment of back pain; Vertebroplastie zur Therapie des Rueckenschmerzes

    Energy Technology Data Exchange (ETDEWEB)

    Trumm, C.G.; Jakobs, T.F.; Zech, C.J.; Weber, C.; Reiser, M.F.; Hoffmann, R.T. [Klinikum Grosshadern der Ludwig-Maximilians-Universitaet, Institut fuer Klinische Radiologie, Muenchen (Germany)

    2006-06-15

    Beitrag sollen Indikationsstellung, periinterventionelle Bildgebung, Technik und klinische Ergebnisse der PVP dargestellt werden. Gemaess dem ''Interdisziplinaeren Konsensuspapier zur Vertebro- und Kyphoplastie'' der deutschen Fachgesellschaften sowie den Leitlinien der CIRSE aus dem Jahr 2005 werden die aktuellen Richtlinien zur Durchfuehrung der PVP erlaeutert. Die Ergebnisse einer eigenen Studie werden Komplikationsraten und klinischen Ergebnissen in der Literatur gegenuebergestellt. Die Indikation zur PVP besteht bei schmerzhaften osteoporotischen WKF und Wirbelkoerperosteolysen durch Metastasen und das multiple Myelom. Absolute Kontraindikationen sind v. a. asymptomatische WKF, eine Beschwerdelinderung unter medikamentoeser Therapie, therapierefraktaere Koagulopathien, Allergien gegen Zementbestandteile und aktive Infektionen. Zur Abschaetzung des Frakturalters, Ausschluss anderer Schmerzursachen und Beurteilung der Wirbelkoerperhinterkante sind vor der PVP eine MRT bzw. CT indiziert. Eine qualitativ hochwertige mono- oder biplanare Fluoroskopie - moeglichst in Kombination mit der CT(-Fluoroskopie) - sind bei der PVP erforderlich, um das Risiko von Zementleckagen zu minimieren. Bei 86-92% der Patienten wird durch die PVP eine deutliche Schmerzreduktion (mittlere Abnahme von 6,1 Punkten [VAS]) erreicht. Eine eigene Studie mit 58 behandelten Patienten (mittlerer Beobachtungszeitraum 323+/-99 Tage) zeigte in 77% der Faelle eine deutliche Beschwerdelinderung (-5,7 Punkte [VAS]). Die PVP ermoeglicht bei akutem und chronischem Rueckenschmerz durch osteoporotische WKF und tumorbedingte Osteolysen eine sichere und effektive minimalinvasive Therapie zur Stabilisierung und Schmerzreduktion. (orig.)

  18. Studies on agglomeration of colloidal suspensions in an alternating electric field; Untersuchungen zur Agglomeration kolloidaler Suspensionen im elektrischen Wechselfeld

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, M. [Inst. fuer Mechanische Verfahrenstechnik und Mechanik, Univ. Karlsruhe (Germany); Loeffler, F. [Inst. fuer Mechanische Verfahrenstechnik und Mechanik, Univ. Karlsruhe (Germany)

    1996-07-01

    Colloidal solutions contain particles in the {mu}m range whose agglomeration and coagulation is of interest for certain applications. `Electrocoagulation` means that in an electric field droplets or particles in a disperse phase have higher kinetic energy so that the probability of overcoming repulsive forces and of forming bigger aggregates will increase. The electrocoagulation technique is applied for emulsion cracking of water-in-oil systems (desalination and dewatering of petroleum, petroleum cracking) and, in some cases, also for cracking oil-in-water systems. Removal of colloidal solids from aqueous solution during electrochemical waste water treatment is often carried out with the aid of dissolving aluminium or iron electrodes. The authors describe experiments in which the flow of an electric current, which would cause the electrodes to dissolve, was to be prevented. An alternating field was to induce oscillation of the particles, i.e. relative motion of the particles with respect to each other. (orig./SR) [Deutsch] Kolloidale Loesungen enthalten Partikel im {mu}m-Bereich. In manchen Bereichen ist deren Agglomeration bzw. Koagulation von Interesse. Unter dem Begriff der Elektrokoagulation versteht man im allgemeinen das Phaenomen, dass in einem elektrischen Feld Tropfen oder Partikel in einer dispersen Phase eine hoehere kinetische Energie besitzen, und dadurch die Wahrscheinlichkeit zur Ueberwindung von Abstossungskraeften und zur Bildung groesserer Aggregate steigt. Das Verfahren der Elektrokoagulation wird bisher zur Emulsionsspaltung von Wasser/Oel-Systemen (Entsaltzung und Entwaesserung von Erdoel/Erdoelspaltung) und z.T. auch zur Spaltung von Oel/Wasser-Systemen eingesetzt. Zur Entfernung kolloidaler Feststoffe aus waessrigen Loesungen bei der elektrochemischen Aufarbeitung von Abwasser wird haeufig mit sich aufloesenden Aluminium- oder Eisenelektroden gearbeitet. In den im folgenden dargestellten Untersuchungen sollte ein Stromfluss durch die

  19. Photon-photon and photon-hadron processes in relativistic heavy ion collisions

    International Nuclear Information System (INIS)

    Baron, N.C.

    1993-11-01

    Photon-photon and photon-hadron interactions in relativistic heavy ion collisions are studied in the framework of the impact parameter dependent equivalent photon approximation. Improvements of this method, like formfactor inclusion and geometrical modifications are developed. In disruptive relativistic heavy ion collisions where the heavy ions overlapp during the collision, electromagnetic processes are an important background to other mechanisms. In peripheral (non-disruptive) relativistic heavy ion collisions where the ions pass each other without strong interactions, the electromagnetic processes can be studied in their pure form. The lepton pair production is an important diagnostic tool in relativistic heavy ion collisions. The coherent γγ lepton pair production is therefore extensively studied in disruptive but also in non-disruptive collisions. The effects of strong interactions on the coherent γγ lepton pair production in disruptive collisions are discussed in terms of a simple stopping model. Coherent γγ dielectron production contributes to the dilepton production in high energy hadron-hadron collisions. As an example, the coherent dielectron production in π - p collisions is studied in terms of the equivalent photon approximation. Peripheral ultrarelativistic heavy ion collisions open up new possibilities for γγ physics. Taking into account γA background reactions, typical γγ processes in the relevant invariant mass ranges are discussed. The extreme high energy part of the equivalent photon spectrum leads to hard photon-parton reactions. As a potential tool to investigate the gluon distribution function of nucleons, thee q anti q production via the γg fusion in ultrarelativistic heavy ion collisions is studied. It is the purpose of this work to investigate how photon-photon and photon-hadron reactions in relativistic heavy ion collisions may contribute to the understanding of QCD and the standard model. (orig.) [de

  20. ITMO Photonics: center of excellence

    Science.gov (United States)

    Voznesenskaya, Anna; Bougrov, Vladislav; Kozlov, Sergey; Vasilev, Vladimir

    2016-09-01

    ITMO University, the leading Russian center in photonics research and education, has the mission to train highlyqualified competitive professionals able to act in conditions of fast-changing world. This paradigm is implemented through creation of a strategic academic unit ITMO Photonics, the center of excellence concentrating organizational, scientific, educational, financial, laboratory and human resources. This Center has the following features: dissemination of breakthrough scientific results in photonics such as advanced photonic materials, ultrafast optical and quantum information, laser physics, engineering and technologies, into undergraduate and graduate educational programs through including special modules into the curricula and considerable student's research and internships; transformation of the educational process in accordance with the best international educational practices, presence in the global education market in the form of joint educational programs with leading universities, i.e. those being included in the network programs of international scientific cooperation, and international accreditation of educational programs; development of mechanisms for the commercialization of innovative products - results of scientific research; securing financial sustainability of research in the field of photonics of informationcommunication systems via funding increase and the diversification of funding sources. Along with focusing on the research promotion, the Center is involved in science popularization through such projects as career guidance for high school students; interaction between student's chapters of international optical societies; invited lectures of World-famous experts in photonics; short educational programs in optics, photonics and light engineering for international students; contests, Olympics and grants for talented young researchers; social events; interactive demonstrations.

  1. Quantum mechanics of a photon

    Science.gov (United States)

    Babaei, Hassan; Mostafazadeh, Ali

    2017-08-01

    A first-quantized free photon is a complex massless vector field A =(Aμ ) whose field strength satisfies Maxwell's equations in vacuum. We construct the Hilbert space H of the photon by endowing the vector space of the fields A in the temporal-Coulomb gauge with a positive-definite and relativistically invariant inner product. We give an explicit expression for this inner product, identify the Hamiltonian for the photon with the generator of time translations in H , determine the operators representing the momentum and the helicity of the photon, and introduce a chirality operator whose eigenfunctions correspond to fields having a definite sign of energy. We also construct a position operator for the photon whose components commute with each other and with the chirality and helicity operators. This allows for the construction of the localized states of the photon with a definite sign of energy and helicity. We derive an explicit formula for the latter and compute the corresponding electric and magnetic fields. These turn out to diverge not just at the point where the photon is localized but on a plane containing this point. We identify the axis normal to this plane with an associated symmetry axis and show that each choice of this axis specifies a particular position operator, a corresponding position basis, and a position representation of the quantum mechanics of a photon. In particular, we examine the position wave functions determined by such a position basis, elucidate their relationship with the Riemann-Silberstein and Landau-Peierls wave functions, and give an explicit formula for the probability density of the spatial localization of the photon.

  2. Quantum imaging with undetected photons.

    Science.gov (United States)

    Lemos, Gabriela Barreto; Borish, Victoria; Cole, Garrett D; Ramelow, Sven; Lapkiewicz, Radek; Zeilinger, Anton

    2014-08-28

    Information is central to quantum mechanics. In particular, quantum interference occurs only if there exists no information to distinguish between the superposed states. The mere possibility of obtaining information that could distinguish between overlapping states inhibits quantum interference. Here we introduce and experimentally demonstrate a quantum imaging concept based on induced coherence without induced emission. Our experiment uses two separate down-conversion nonlinear crystals (numbered NL1 and NL2), each illuminated by the same pump laser, creating one pair of photons (denoted idler and signal). If the photon pair is created in NL1, one photon (the idler) passes through the object to be imaged and is overlapped with the idler amplitude created in NL2, its source thus being undefined. Interference of the signal amplitudes coming from the two crystals then reveals the image of the object. The photons that pass through the imaged object (idler photons from NL1) are never detected, while we obtain images exclusively with the signal photons (from NL1 and NL2), which do not interact with the object. Our experiment is fundamentally different from previous quantum imaging techniques, such as interaction-free imaging or ghost imaging, because now the photons used to illuminate the object do not have to be detected at all and no coincidence detection is necessary. This enables the probe wavelength to be chosen in a range for which suitable detectors are not available. To illustrate this, we show images of objects that are either opaque or invisible to the detected photons. Our experiment is a prototype in quantum information--knowledge can be extracted by, and about, a photon that is never detected.

  3. Photon energy tunability of advanced photon source undulators

    International Nuclear Information System (INIS)

    Viccaro, P.J.; Shenoy, G.K.

    1987-08-01

    At a fixed storage ring energy, the energy of the harmonics of an undulator can be shifted or ''tuned'' by changing the magnet gap of the device. The possible photon energy interval spanned in this way depends on the undulator period, minimum closed gap, minimum acceptable photon intensity and storage ring energy. The minimum magnet gap depends directly on the stay clear particle beam aperture required for storage ring operation. The tunability of undulators planned for the Advanced Photon Source with first harmonic photon energies in the range of 5 to 20 keV are discussed. The results of an analysis used to optimize the APS ring energy is presented and tunability contours and intensity parameters are presented for two typical classes of devices

  4. Photon-counting image sensors

    CERN Document Server

    Teranishi, Nobukazu; Theuwissen, Albert; Stoppa, David; Charbon, Edoardo

    2017-01-01

    The field of photon-counting image sensors is advancing rapidly with the development of various solid-state image sensor technologies including single photon avalanche detectors (SPADs) and deep-sub-electron read noise CMOS image sensor pixels. This foundational platform technology will enable opportunities for new imaging modalities and instrumentation for science and industry, as well as new consumer applications. Papers discussing various photon-counting image sensor technologies and selected new applications are presented in this all-invited Special Issue.

  5. Photonics activities at DTU Fotonik

    DEFF Research Database (Denmark)

    Jeppesen, Palle; Jepsen, Peter Uhd; Lodahl, Peter

    2010-01-01

    DTU Fotonik, Department of Photonics Engineering at the Technical University of Denmark has about 200 employees including 60 PhD students. The ambition is to be among the world’s leading University departments within photonics research, education and innovation. To fulfil this ambition, DTU Fotonik...... tries to attract excellent researchers and students from all over the world and to collaborate with world leading research institutes and companies. The activities span from quantum photonics, nanotechnology and metamaterials over nonlinear fiber optics, optical sensors and diode lasers & LED systems...

  6. Ultrafast Graphene Photonics and Optoelectronics

    Science.gov (United States)

    2017-04-14

    AFRL-AFOSR-JP-TR-2017-0032 Ultrafast Graphene Photonics and Optoelectronics Kuang-Hsiung Wu National Chiao Tung University Final Report 04/14/2017...DATES COVERED (From - To) 18 Apr 2013 to 17 Apr 2016 4. TITLE AND SUBTITLE Ultrafast Graphene Photonics and Optoelectronics 5a.  CONTRACT NUMBER 5b...Prescribed by ANSI Std. Z39.18 Final Report for AOARD Grant FA2386-13-1-4022 “Ultrafast Graphene Photonics and Optoelectronics” Date May 23th, 2016

  7. Slow Images and Entangled Photons

    International Nuclear Information System (INIS)

    Swordy, Simon

    2007-01-01

    I will discuss some recent experiments using slow light and entangled photons. We recently showed that it was possible to map a two dimensional image onto very low light level signals, slow them down in a hot atomic vapor while preserving the amplitude and phase of the images. If time remains, I will discuss some of our recent work with time-energy entangled photons for quantum cryptography. We were able to show that we could have a measurable state space of over 1000 states for a single pair of entangled photons in fiber.

  8. Photonic Microresonator Research and Applications

    CERN Document Server

    Chremmos, Ioannis; Uzunoglu, Nikolaos

    2010-01-01

    Photonic Microresonator Research and Applications explores advances in the fabrication process that enable nanometer waveguide separations. The technology surrounding the design and fabrication of optical microresonators has matured to a point where there is a need for commercialization. Consequently, there is a need for device research involving more advanced architectures and more esoteric operating princples. This volume discusses these issues, while also: Showing a reader how to design and fabricate microresonators Discussing microresonators in photonic crystals, microsphere circuits, and sensors, and provides application oriented examples Covering the latest in microresonator research with contributions from the leading researchers Photonic Microresonator Research and Applications would appeal to researchers and academics working in the optical sciences.

  9. Summary of Lepton Photon 2011

    Energy Technology Data Exchange (ETDEWEB)

    Peskin, Michael E.; /SLAC

    2012-03-14

    In this lecture, I summarize developments presented at the Lepton Photon 2011 conference and give my perspective on the current situation in high-energy physics. I am grateful to the organizers of Lepton Photon 2011 for providing us a very pleasant and simulating week in Mumbai. This year's Lepton Photon conference has covered the full range of subjects that fall within the scope of high-energy physics, including connections to cosmology, nuclear physics, and atomic physics. The experiments that were discussed detect particles ranging in energy from radio frequencies to EeV.

  10. Random photonic crystal optical memory

    International Nuclear Information System (INIS)

    Wirth Lima Jr, A; Sombra, A S B

    2012-01-01

    Currently, optical cross-connects working on wavelength division multiplexing systems are based on optical fiber delay lines buffering. We designed and analyzed a novel photonic crystal optical memory, which replaces the fiber delay lines of the current optical cross-connect buffer. Optical buffering systems based on random photonic crystal optical memory have similar behavior to the electronic buffering systems based on electronic RAM memory. In this paper, we show that OXCs working with optical buffering based on random photonic crystal optical memories provides better performance than the current optical cross-connects. (paper)

  11. Untersuchungen zur Expansion, funktionellen Charakterisierung und kontinuierlichen Bereitstellung von Hepatocyten für die Anwendung in bioartifiziellen Leberunterstützungssystemen

    OpenAIRE

    Iding, Kai

    2001-01-01

    Der vollständige Funktionsverlust der Leber kann in der modernen Medizin bisher nur durch den Austausch des funktionsuntüchtigen gegen ein gesundes Organ, d.h. durch eine Lebertransplantation behandelt werden. Da es jedoch weit mehr transplantationsbedürftige Patienten gibt als geeignete Spenderorgane zur Verfügung stehen, gibt es weltweite Anstrengungen zur Entwicklung alternativer Behandlungsmethoden. Nach bisherigem wissenschaftlichen Erkenntnisstand ist die bioartifizielle Leberunterst...

  12. Photon-Photon Luminosities in Relativistic Heavy Ion Collisions at LHC Energies

    OpenAIRE

    Hencken, Kai; Trautmann, Dirk; Baur, Gerhard

    1994-01-01

    Effective photon-photon luminosities are calculated for various realistic hadron collider scenarios. The main characteristics of photon-photon processes at relativistic heavy-ion colliders are established and compared to the corresponding photon-photon luminosities at electron-positron and future Photon Linear Colliders (PLC). Higher order corrections as well as inelastic processes are discussed. It is concluded that feasible high luminosity Ca-Ca collisions at the Large Hadron Collider (LHC)...

  13. Tailoring single-photon and multiphoton probabilities of a single-photon on-demand source

    International Nuclear Information System (INIS)

    Migdall, A.L.; Branning, D.; Castelletto, S.

    2002-01-01

    As typically implemented, single-photon sources cannot be made to produce single photons with high probability, while simultaneously suppressing the probability of yielding two or more photons. Because of this, single-photon sources cannot really produce single photons on demand. We describe a multiplexed system that allows the probabilities of producing one and more photons to be adjusted independently, enabling a much better approximation of a source of single photons on demand

  14. Energy report for Bavaria, 1996/97. Data on the development of the Bavarian energy industry, with an energy balance; Energiebericht Bayern 1996/97. Daten zur Entwicklung der bayerischen Energiewirtschaft mit Energiebilanz

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-04-01

    The report presents the energy balance for Bavaria and provides information on: Bavarian energy industry; structure and development of primary and end-use energy consumption; situation and development of energy sources (electricity, gas, mineral oil, coal, district heating). (orig.) [Deutsch] Der Bericht enthaelt die Energiebilanz Bayern fuer das Berichtsjahr und bietet Informationen zur Energiewirtschaft in Bayern, zur Struktur und Entwicklung des Primaer- und Endenergieverbrauchs und zur Situation und Entwicklung bei den einzelnen Energietraegern (Elektrizitaet, Gas, Mineraloel, Kohle, Fernwaerme). (orig.)

  15. gPhoton: THE GALEX PHOTON DATA ARCHIVE

    Energy Technology Data Exchange (ETDEWEB)

    Million, Chase [Million Concepts LLC, P.O. Box 119, 141 Mary Street, Lemont, PA 16851 (United States); Fleming, Scott W.; Shiao, Bernie; Smith, Myron; Thompson, Randy; White, Richard L. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Seibert, Mark [The Observatories of the Carnegie Institution of Washington, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Loyd, Parke [Laboratory for Atmospheric and Space Physics, Boulder, Colorado, 80309 (United States); Tucker, Michael [Dept. of Physics and Astronomy, Appalachian State University, Boone, NC 28608 (United States)

    2016-12-20

    gPhoton is a new database product and software package that enables analysis of GALEX ultraviolet data at the photon level. The project’s stand-alone, pure-Python calibration pipeline reproduces the functionality of the original mission pipeline to reduce raw spacecraft data to lists of time-tagged, sky-projected photons, which are then hosted in a publicly available database by the Mikulski Archive at Space Telescope. This database contains approximately 130 terabytes of data describing approximately 1.1 trillion sky-projected events with a timestamp resolution of five milliseconds. A handful of Python and command-line modules serve as a front end to interact with the database and to generate calibrated light curves and images from the photon-level data at user-defined temporal and spatial scales. The gPhoton software and source code are in active development and publicly available under a permissive license. We describe the motivation, design, and implementation of the calibration pipeline, database, and tools, with emphasis on divergence from prior work, as well as challenges created by the large data volume. We summarize the astrometric and photometric performance of gPhoton relative to the original mission pipeline. For a brief example of short time-domain science capabilities enabled by gPhoton, we show new flares from the known M-dwarf flare star CR Draconis. The gPhoton software has permanent object identifiers with the ASCL (ascl:1603.004) and DOI (doi:10.17909/T9CC7G). This paper describes the software as of version v1.27.2.

  16. Vector-vector production in photon-photon interactions

    International Nuclear Information System (INIS)

    Ronan, M.T.

    1988-01-01

    Measurements of exclusive untagged /rho/ 0 /rho/ 0 , /rho//phi/, K/sup *//bar K//sup */, and /rho/ω production and tagged /rho/ 0 /rho/ 0 production in photon-photon interactions by the TPC/Two-Gamma experiment are reviewed. Comparisons to the results of other experiments and to models of vector-vector production are made. Fits to the data following a four quark model prescription for vector meson pair production are also presented. 10 refs., 9 figs

  17. The photonic nanowire: A highly efficient single-photon source

    DEFF Research Database (Denmark)

    Gregersen, Niels

    2014-01-01

    The photonic nanowire represents an attractive platform for a quantum light emitter. However, careful optical engineering using the modal method, which elegantly allows access to all relevant physical parameters, is crucial to ensure high efficiency.......The photonic nanowire represents an attractive platform for a quantum light emitter. However, careful optical engineering using the modal method, which elegantly allows access to all relevant physical parameters, is crucial to ensure high efficiency....

  18. Engineering Photon-Photon Interactions within Rubidium-Filled Waveguides

    Science.gov (United States)

    Perrella, C.; Light, P. S.; Vahid, S. Afshar; Benabid, F.; Luiten, A. N.

    2018-04-01

    Strong photon-photon interactions are a required ingredient for deterministic two-photon optical quantum logic gates. Multiphoton transitions in dense atomic vapors have been shown to be a promising avenue for producing such interactions. The strength of a multiphoton interaction can be enhanced by conducting the interaction in highly confined geometries such as small-cross-section optical waveguides. We demonstrate, both experimentally and theoretically, that the strength of such interactions scale only with the optical mode diameter, d , not d2 as might be initially expected. This weakening of the interaction arises from atomic motion inside the waveguides. We create an interaction between two optical signals, at 780 and 776 nm, using the 5 S1 /2→5 D5 /2 two-photon transition in rubidium vapor within a range of hollow-core fibers with different core sizes. The interaction strength is characterized by observing the absorption and phase shift induced on the 780-nm beam, which is in close agreement with theoretical modeling that accounts for the atomic motion inside the fibers. These observations demonstrate that transit-time effects upon multiphoton transitions are of key importance when engineering photon-photon interactions within small-cross-section waveguides that might otherwise be thought to lead to enhanced optical nonlinearity through increased intensities.

  19. EDITORIAL: Photonic terahertz technology

    Science.gov (United States)

    Lisauskas, Alvydas; Löffler, Torsten; Roskos, Hartmut G.

    2005-07-01

    In recent years, when reading newspapers and journals or watching TV, one has been able to find feature presentations dealing with the prospects of terahertz (THz) technology and its potential impact on market applications. THz technology aims to fill the THz gap in the electro-magnetic spectrum in order to make the THz frequency regime, which spans the two orders of magnitude from 100 GHz to 10 THz, accessible for applications. From the lower-frequency side, electronics keeps pushing upwards, while photonic approaches gradually improve our technological options at higher frequencies. The popular interest reflects the considerable advances in research in the THz field, and it is mainly advances in the photonic branch, with the highlight being the development of the THz quantum cascade laser, which in recent years have caught the imagination of the public, and of potential users and investors. This special issue of Semiconductor Science and Technology provides an overview of key scientific developments which currently represent the cutting edge of THz photonic technology. In order to be clear about the implications, we should define exactly what we mean by 'THz photonic technology', or synonymously 'THz photonics'. It is characterized by the way in which THz radiation (or a guided THz wave) is generated, namely by the use of lasers. This may be done in one of two fundamentally different schemes: (i) by laser action in the terahertz frequency range itself (THz lasers), or (ii) by down-conversion processes (photomixing) involving the radiation of lasers which operate in the visible, near-infrared or infrared spectral ranges, either in pulsed or continuous-wave mode. The field of THz photonics has grown so considerably that it is out of the question to cover all its aspects in a single special issue of a journal. We have elected, instead, to focus our attention on two types of development with a potentially strong impact on the THz field: first, on significant advances

  20. Photonics for aerospace sensors

    Science.gov (United States)

    Pellegrino, John; Adler, Eric D.; Filipov, Andree N.; Harrison, Lorna J.; van der Gracht, Joseph; Smith, Dale J.; Tayag, Tristan J.; Viveiros, Edward A.

    1992-11-01

    The maturation in the state-of-the-art of optical components is enabling increased applications for the technology. Most notable is the ever-expanding market for fiber optic data and communications links, familiar in both commercial and military markets. The inherent properties of optics and photonics, however, have suggested that components and processors may be designed that offer advantages over more commonly considered digital approaches for a variety of airborne sensor and signal processing applications. Various academic, industrial, and governmental research groups have been actively investigating and exploiting these properties of high bandwidth, large degree of parallelism in computation (e.g., processing in parallel over a two-dimensional field), and interconnectivity, and have succeeded in advancing the technology to the stage of systems demonstration. Such advantages as computational throughput and low operating power consumption are highly attractive for many computationally intensive problems. This review covers the key devices necessary for optical signal and image processors, some of the system application demonstration programs currently in progress, and active research directions for the implementation of next-generation architectures.

  1. Patterned Colloidal Photonic Crystals.

    Science.gov (United States)

    Hou, Jue; Li, Mingzhu; Song, Yanlin

    2018-03-01

    Colloidal photonic crystals (PCs) have been well developed because they are easy to prepare, cost-effective, and versatile with regards to modification and functionalization. Patterned colloidal PCs contribute a novel approach to constructing high-performance PC devices with unique structures and specific functions. In this review, an overview of the strategies for fabricating patterned colloidal PCs, including patterned substrate-induced assembly, inkjet printing, and selective immobilization and modification, is presented. The advantages of patterned PC devices are also discussed in detail, for example, improved detection sensitivity and response speed of the sensors, control over the flow direction and wicking rate of microfluidic channels, recognition of cross-reactive molecules through an array-patterned microchip, fabrication of display devices with tunable patterns, well-arranged RGB units, and wide viewing-angles, and the ability to construct anti-counterfeiting devices with different security strategies. Finally, the perspective of future developments and challenges is presented. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. THE PHOTON UNDERPRODUCTION CRISIS

    International Nuclear Information System (INIS)

    Kollmeier, Juna A.; Weinberg, David H.; McEwen, Joseph; Oppenheimer, Benjamin D.; Danforth, Charles; Haardt, Francesco; Katz, Neal; Fardal, Mark; Davé, Romeel; Madau, Piero; Ford, Amanda B.; Peeples, Molly S.

    2014-01-01

    We examine the statistics of the low-redshift Lyα forest from smoothed particle hydrodynamic simulations in light of recent improvements in the estimated evolution of the cosmic ultraviolet background (UVB) and recent observations from the Cosmic Origins Spectrograph (COS). We find that the value of the metagalactic photoionization rate (Γ HI ) required by our simulations to match the observed properties of the low-redshift Lyα forest is a factor of five larger than the value predicted by state-of-the art models for the evolution of this quantity. This mismatch in Γ HI results in the mean flux decrement of the Lyα forest being overpredicted by at least a factor of two (a 10σ discrepancy with observations) and a column density distribution of Lyα forest absorbers systematically and significantly elevated compared to observations over nearly two decades in column density. We examine potential resolutions to this mismatch and find that either conventional sources of ionizing photons (galaxies and quasars) must contribute considerably more than current observational estimates or our theoretical understanding of the low-redshift universe is in need of substantial revision

  3. Photon interactions with nuclei

    International Nuclear Information System (INIS)

    Thornton, S.T.; Sealock, R.M.

    1989-01-01

    This document is a progress report for DOE Grant No. FG05-89ER40501, A000. The grant began March, 1989. Our primary research effort has been expended at the LEGS project at Brookhaven National Laboratory. This report will summarize our present research effort at LEGS as well as data analysis and publications from previous experiments performed at SLAC. In addition the principal investigators are heavily involved in the CLAS collaboration in Hall B at CEBAF. We have submitted several letters of intent and proposals and have made commitments to construct experimental equipment for CEBAF. We expect our primary experimental effort to continue at LEGS until CEBAF becomes operational. This report will be divided into separate sections describing our progress at LEGS, SLAC, and CEBAF. We will also discuss our significant efforts in the education and training of both undergraduate and graduate students. Photon detectors are described as well as experiments on delta deformation in nuclei of quasielastic scattering and excitation of the delta by 4 He(e,e')

  4. Thermoelectric single-photon detector

    International Nuclear Information System (INIS)

    Kuzanyan, A A; Petrosyan, V A; Kuzanyan, A S

    2012-01-01

    The ability to detect a single photon is the ultimate level of sensitivity in the measurement of optical radiation. Sensors capable of detecting single photons and determining their energy have many scientific and technological applications. Kondo-enhanced Seebeck effect cryogenic detectors are based on thermoelectric heat-to-voltage conversion and voltage readout. We evaluate the prospects of CeB 6 and (La,Ce)B 6 hexaboride crystals for their application as a sensitive element in this type of detectors. We conclude that such detectors can register a single UV photon, have a fast count rate (up to 45 MHz) and a high spectral resolution of 0.1 eV. We calculate the electric potential generated along the thermoelectric sensor upon registering a UV single photon.

  5. Manipulating continuous variable photonic entanglement

    International Nuclear Information System (INIS)

    Plenio, M.B.

    2005-01-01

    I will review our work on photonic entanglement in the continuous variable regime including both Gaussian and non-Gaussian states. The feasibility and efficiency of various entanglement purification protocols are discussed this context. (author)

  6. Femtosecond Photon-Counting Receiver

    Science.gov (United States)

    Krainak, Michael A.; Rambo, Timothy M.; Yang, Guangning; Lu, Wei; Numata, Kenji

    2016-01-01

    An optical correlation receiver is described that provides ultra-precise distance and/or time/pulse-width measurements even for weak (single photons) and short (femtosecond) optical signals. A new type of optical correlation receiver uses a fourth-order (intensity) interferometer to provide micron distance measurements even for weak (single photons) and short (femtosecond) optical signals. The optical correlator uses a low-noise-integrating detector that can resolve photon number. The correlation (range as a function of path delay) is calculated from the variance of the photon number of the difference of the optical signals on the two detectors. Our preliminary proof-of principle data (using a short-pulse diode laser transmitter) demonstrates tens of microns precision.

  7. Photon management in solar cells

    CERN Document Server

    Rau, Uwe; Gombert, Andreas

    2015-01-01

    Written by renowned experts in the field of photon management in solar cells, this one-stop reference gives an introduction to the physics of light management in solar cells, and discusses the different concepts and methods of applying photon management. The authors cover the physics, principles, concepts, technologies, and methods used, explaining how to increase the efficiency of solar cells by splitting or modifying the solar spectrum before they absorb the sunlight. In so doing, they present novel concepts and materials allowing for the cheaper, more flexible manufacture of solar cells and systems. For educational purposes, the authors have split the reasons for photon management into spatial and spectral light management. Bridging the gap between the photonics and the photovoltaics communities, this is an invaluable reference for materials scientists, physicists in industry, experimental physicists, lecturers in physics, Ph.D. students in physics and material sciences, engineers in power technology, appl...

  8. Nano lasers in photonic VLSI

    NARCIS (Netherlands)

    Hill, M.T.; Oei, Y.S.; Smit, M.K.

    2007-01-01

    We examine the use of micro and nano lasers to form digital photonic VLSI building blocks. Problems such as isolation and cascading of building blocks are addressed, and the potential of future nano lasers explored.

  9. Modelling of photonic crystal fibres

    DEFF Research Database (Denmark)

    Knudsen, Erik

    2003-01-01

    , as well as a honeycomb bandgap fibre and the first analysis of semi-periodic layered air-hole fibres. Using the modelling framework established as a basis, we provide an analysis of microbend loss, by regarding displacement of a fibre core as a stationary stochastic process, inducing mismatch between......In the presenta ph.d. work a theoretical study of aspects of modelling photonic crystal fibres was carried out. Photonic crystal fibres form a class of optical waveguides where guidance is no longer provided by a difference in refractive index between core and cladding. Instead, guidance...... is provided by an arrangement of air-holes running along the length of the fibre. Depending on the geometry of the fibre, the guiding mechanism may be either arising from the formation of a photonic bandgap in the cladding structure (photonic bandgap fibre), or by an effect resembling total internal...

  10. Quantum photonic networks in diamond

    KAUST Repository

    Lončar, Marko; Faraon, Andrei

    2013-01-01

    Advances in nanotechnology have enabled the opportunity to fabricate nanoscale optical devices and chip-scale systems in diamond that can generate, manipulate, and store optical signals at the single-photon level. In particular, nanophotonics has

  11. Parity-Time Symmetric Photonics

    KAUST Repository

    Zhao, Han

    2018-01-17

    The establishment of non-Hermitian quantum mechanics (such as parity-time (PT) symmetry) stimulates a paradigmatic shift for studying symmetries of complex potentials. Owing to the convenient manipulation of optical gain and loss in analogy to the complex quantum potentials, photonics provides an ideal platform for visualization of many conceptually striking predictions from the non-Hermitian quantum theory. A rapidly developing field has emerged, namely, PT symmetric photonics, demonstrating intriguing optical phenomena including eigenstate coalescence and spontaneous PT symmetry breaking. The advance of quantum physics, as the feedback, provides photonics with brand-new paradigms to explore the entire complex permittivity plane for novel optical functionalities. Here, we review recent exciting breakthroughs in PT symmetric photonics while systematically presenting their underlying principles guided by non-Hermitian symmetries. The potential device applications for optical communication and computing, bio-chemical sensing, and healthcare are also discussed.

  12. Coupling the photon kinetics of soft photons with high energy photons

    Science.gov (United States)

    Silva, L. O.; Bingham, R.

    2017-10-01

    The description of electromagnetic fields based on the generalized photon kinetic theory, which takes advantage of the Wigner-Moyal description for the corresponding classical field theory, is capable of capturing collective plasma dynamics in the relativistic regime driven by broadband incoherent or partially coherent sources. We explore the possibility to extend this description to include the dynamics of hard photons in the plasma, whose interaction is dominated by single scattering processes. Examples of the modification of classical plasma instabilities due to the presence of hard photons is discussed. Work supported by the European Research Council (ERC-AdG-2015 InPairs Grant No. 695088).

  13. National Photonics Skills Standard for Technicians.

    Science.gov (United States)

    Center for Occupational Research and Development, Inc., Waco, TX.

    This document defines "photonics" as the generation, manipulation, transport, detection, and use of light information and energy whose quantum unit is the photon. The range of applications of photonics extends from energy generation to detection to communication and information processing. Photonics is at the heart of today's…

  14. Photon final states at the Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Campanelli, Mario; /University Coll. London

    2008-04-01

    The authors present here several recent measurements involving associate production of photons and jets at the Tevatron. In particular, inclusive photon + met from D0, and photon + b-jets and photon + b-jet + leptons + MET from CDF are described in some detail. These measurements offer a good test of QCD predictions in rather complex final states.

  15. Experimental search for muonic photons

    CERN Document Server

    Vilain, P; Beyer, R; Flegel, Wilfried; Mouthuy, T; Øverås, H; Panman, J; Rozanov, A N; Winter, Klaus; Zacek, G; Zacek, V; Büsser, F W; Foos, C; Gerland, L; Layda, T; Niebergall, F; Rädel, G; Stähelin, P; Voss, T; Favart, D; Grégoire, G; Knoops, E; Lemaître, V; Gorbunov, P; Grigoriev, E A; Ilyin, V A; Khovanskii, V D; Maslennikov, A M; Okun, Lev Borisovich; Lippich, W; Nathaniel, A; Staude, A; Vogt, J; Cocco, A G; Ereditato, A; Fiorillo, G; Marchetti-Stasi, F; Palladino, Vittorio; Strolin, P; Capone, A; De Pedis, D; Dore, U; Frenkel-Rambaldi, A; Loverre, P F; Macina, Daniela; Piredda, G; Santacesaria, R; Di Capua, E; Ricciardi, S; Saitta, B; Akkus, B; Arik, E; Serin-Zeyrek, M; Sever, R; Tolun, P; Hiller, K; Nahnhauer, R; Roloff, H

    1998-01-01

    We report new limits on the production of muonic photons in the CERN neutrino beam. The results are based on the analysis of neutrino production of dimuons in the CHARM II detector. A $90\\%$ CL limit on the coupling constant of muonic photons, $\\alpha_{\\mu} / \\alpha < (1.5 \\div 3.2) \\times10^{-6}$ is derived for a muon neutrino mass in the range $m_{\

  16. Photon factory activity report, 1992

    International Nuclear Information System (INIS)

    1993-01-01

    This issue is the annual report of the Photon Factory, National laboratory of High Energy Physics. First, the outline of the Photon Factory is presented. Injector linac, light source, beamlines and instrumentation, the Tristan synchrotron radiation facility at the accumulation ring, and the Tristan super light facility are described in detail. The facility is open to researchers. The user's reports are collected as well. (J.P.N.) (435 refs.)

  17. Modeling of photonic Crystal Fibres

    DEFF Research Database (Denmark)

    Bjarklev, Anders Overgaard; Broeng, Jes; Barkou, Stig Eigil

    1999-01-01

    Diferent theoretical models for analysis of photonic crystal fibres are reviewed and compaired. The methods span from simple scalar approaches to full-vectorial models using different mode-field decompositions. The specific advantages of the methods are evaluated.......Diferent theoretical models for analysis of photonic crystal fibres are reviewed and compaired. The methods span from simple scalar approaches to full-vectorial models using different mode-field decompositions. The specific advantages of the methods are evaluated....

  18. Topology Optimized Photonic Wire Splitters

    DEFF Research Database (Denmark)

    Frandsen, Lars Hagedorn; Borel, Peter Ingo; Jensen, Jakob Søndergaard

    2006-01-01

    Photonic wire splitters have been designed using topology optimization. The splitters have been fabricated in silicon-on-insulator material and display broadband low-loss 3dB splitting in a bandwidth larger than 100 nm.......Photonic wire splitters have been designed using topology optimization. The splitters have been fabricated in silicon-on-insulator material and display broadband low-loss 3dB splitting in a bandwidth larger than 100 nm....

  19. Photon factory activity report, 1993

    International Nuclear Information System (INIS)

    1994-01-01

    This issue is the annual report of the Photon Factory, National Laboratory of High Energy Physics. First the outline of the Photon Factory is presented. Injector linac, light source, beamlines and instrumentation, synchrotron radiation facility at the Tristan accumulation ring, and the Tristan super light facility are described in detail. The facility is open to researchers. The user's reports are collected as well. (J.P.N.)

  20. Approaches to single photon detection

    International Nuclear Information System (INIS)

    Thew, R.T.; Curtz, N.; Eraerds, P.; Walenta, N.; Gautier, J.-D.; Koller, E.; Zhang, J.; Gisin, N.; Zbinden, H.

    2009-01-01

    We present recent results on our development of single photon detectors, including: gated and free-running InGaAs/InP avalanche photodiodes (APDs); hybrid detection systems based on sum-frequency generation (SFG) and Si APDs-SFG-Si APDs; and SSPDs (superconducting single photon detectors), for telecom wavelengths; as well as SiPM (Silicon photomultiplier) detectors operating in the visible regime.

  1. Spin dependent photon structure functions

    International Nuclear Information System (INIS)

    Manohar, A.V.; Massachusetts Inst. of Tech., Cambridge

    1989-01-01

    Spin dependent structure functions of the photon are studied using the operator product expansion. There are new twist-two photon and gluon operators which contribute. The structure functions g 1 and F 3 are calculable in QCD, but differ from their free quark values. The corrections to F 3 are suppressed by 1/log Q 2 . The calculation is an extension of the analysis of Witten for the spin averaged structure functions F 1 and F 2 . (orig.)

  2. Quasimetallic silicon micromachined photonic crystals

    International Nuclear Information System (INIS)

    Temelkuran, B.; Bayindir, Mehmet; Ozbay, E.; Kavanaugh, J. P.; Sigalas, M. M.; Tuttle, G.

    2001-01-01

    We report on fabrication of a layer-by-layer photonic crystal using highly doped silicon wafers processed by semiconductor micromachining techniques. The crystals, built using (100) silicon wafers, resulted in an upper stop band edge at 100 GHz. The transmission and defect characteristics of these structures were found to be analogous to metallic photonic crystals. We also investigated the effect of doping concentration on the defect characteristics. The experimental results agree well with predictions of the transfer matrix method simulations

  3. Topological Photonics for Continuous Media

    Science.gov (United States)

    Silveirinha, Mario

    Photonic crystals have revolutionized light-based technologies during the last three decades. Notably, it was recently discovered that the light propagation in photonic crystals may depend on some topological characteristics determined by the manner how the light states are mutually entangled. The usual topological classification of photonic crystals explores the fact that these structures are periodic. The periodicity is essential to ensure that the underlying wave vector space is a closed surface with no boundary. In this talk, we prove that it is possible calculate Chern invariants for a wide class of continuous bianisotropic electromagnetic media with no intrinsic periodicity. The nontrivial topology of the relevant continuous materials is linked with the emergence of edge states. Moreover, we will demonstrate that continuous photonic media with the time-reversal symmetry can be topologically characterized by a Z2 integer. This novel classification extends for the first time the theory of electronic topological insulators to a wide range of photonic platforms, and is expected to have an impact in the design of novel photonic systems that enable a topologically protected transport of optical energy. This work is supported in part by Fundacao para a Ciencia e a Tecnologia Grant Number PTDC/EEI-TEL/4543/2014.

  4. Spatial filtering with photonic crystals

    Energy Technology Data Exchange (ETDEWEB)

    Maigyte, Lina [Departament de Física i Enginyeria Nuclear, Universitat Politècnica de Catalunya, Rambla Sant Nebridi 22, Terrassa 08222 (Spain); Staliunas, Kestutis [Departament de Física i Enginyeria Nuclear, Universitat Politècnica de Catalunya, Rambla Sant Nebridi 22, Terrassa 08222 (Spain); Institució Catalana de Recerca i Estudis Avançats (ICREA), Pg. Lluís Companys 23, Barcelona 08010 (Spain)

    2015-03-15

    Photonic crystals are well known for their celebrated photonic band-gaps—the forbidden frequency ranges, for which the light waves cannot propagate through the structure. The frequency (or chromatic) band-gaps of photonic crystals can be utilized for frequency filtering. In analogy to the chromatic band-gaps and the frequency filtering, the angular band-gaps and the angular (spatial) filtering are also possible in photonic crystals. In this article, we review the recent advances of the spatial filtering using the photonic crystals in different propagation regimes and for different geometries. We review the most evident configuration of filtering in Bragg regime (with the back-reflection—i.e., in the configuration with band-gaps) as well as in Laue regime (with forward deflection—i.e., in the configuration without band-gaps). We explore the spatial filtering in crystals with different symmetries, including axisymmetric crystals; we discuss the role of chirping, i.e., the dependence of the longitudinal period along the structure. We also review the experimental techniques to fabricate the photonic crystals and numerical techniques to explore the spatial filtering. Finally, we discuss several implementations of such filters for intracavity spatial filtering.

  5. Ultra-broadband photonic internet

    Science.gov (United States)

    Romaniuk, Ryszard S.

    2011-06-01

    In this paper, there is presented a review of our today's understanding of the ultimately broadband photonic Internet. A simple calculation is presented showing the estimate of the throughput of the core photonic network branches. Optoelectronic components, circuits, systems and signals, together with analogous electronic entities and common software layers, are building blocks of the contemporary Internet. Participation of photonics in development of the physical layer in the future Internet will probably increase. The photonics leads now to a better usage of the available bandwidth (increase of the spectral efficiency measured in Bit/s/Hz), increase in the transmission rate (from Gbps, via Tbps up to probably Pbps), increase in the transmission distance without signal regeneration (in distortion compensated active optical cables), increase in energy/power efficiency measured in W/Gbps, etc. Photonics may lead, in the future, to fully transparent optical networks and, thus, to essential increase in bandwidth and network reliability. It is expected that photonics (with biochemistry, electronics and mechatronics) may build psychological and physiological interface for humans to the future global network. The following optical signal multiplexing methods were considered, which are possible without O/E/O conversion: TDM-OTDM, FDM-CO-OFDM, OCDM-OCDMA, WDM-DWDM.

  6. Tunable Multiband Microwave Photonic Filters

    Directory of Open Access Journals (Sweden)

    Mable P. Fok

    2017-11-01

    Full Text Available The increasing demand for multifunctional devices, the use of cognitive wireless technology to solve the frequency resource shortage problem, as well as the capabilities and operational flexibility necessary to meet ever-changing environment result in an urgent need of multiband wireless communications. Spectral filter is an essential part of any communication systems, and in the case of multiband wireless communications, tunable multiband RF filters are required for channel selection, noise/interference removal, and RF signal processing. Unfortunately, it is difficult for RF electronics to achieve both tunable and multiband spectral filtering. Recent advancements of microwave photonics have proven itself to be a promising candidate to solve various challenges in RF electronics including spectral filtering, however, the development of multiband microwave photonic filtering still faces lots of difficulties, due to the limited scalability and tunability of existing microwave photonic schemes. In this review paper, we first discuss the challenges that were facing by multiband microwave photonic filter, then we review recent techniques that have been developed to tackle the challenge and lead to promising developments of tunable microwave photonic multiband filters. The successful design and implementation of tunable microwave photonic multiband filter facilitate the vision of dynamic multiband wireless communications and radio frequency signal processing for commercial, defense, and civilian applications.

  7. Computational Modeling of Photonic Crystal Microcavity Single-Photon Emitters

    Science.gov (United States)

    Saulnier, Nicole A.

    Conventional cryptography is based on algorithms that are mathematically complex and difficult to solve, such as factoring large numbers. The advent of a quantum computer would render these schemes useless. As scientists work to develop a quantum computer, cryptographers are developing new schemes for unconditionally secure cryptography. Quantum key distribution has emerged as one of the potential replacements of classical cryptography. It relics on the fact that measurement of a quantum bit changes the state of the bit and undetected eavesdropping is impossible. Single polarized photons can be used as the quantum bits, such that a quantum system would in some ways mirror the classical communication scheme. The quantum key distribution system would include components that create, transmit and detect single polarized photons. The focus of this work is on the development of an efficient single-photon source. This source is comprised of a single quantum dot inside of a photonic crystal microcavity. To better understand the physics behind the device, a computational model is developed. The model uses Finite-Difference Time-Domain methods to analyze the electromagnetic field distribution in photonic crystal microcavities. It uses an 8-band k · p perturbation theory to compute the energy band structure of the epitaxially grown quantum dots. We discuss a method that combines the results of these two calculations for determining the spontaneous emission lifetime of a quantum dot in bulk material or in a microcavity. The computational models developed in this thesis are used to identify and characterize microcavities for potential use in a single-photon source. The computational tools developed are also used to investigate novel photonic crystal microcavities that incorporate 1D distributed Bragg reflectors for vertical confinement. It is found that the spontaneous emission enhancement in the quasi-3D cavities can be significantly greater than in traditional suspended slab

  8. Neutron-induced photon production in MCNP

    International Nuclear Information System (INIS)

    Little, R.C.; Seamon, R.E.

    1983-01-01

    An improved method of neutron-induced photon production has been incorporated into the Monte Carlo transport code MCNP. The new method makes use of all partial photon-production reaction data provided by ENDF/B evaluators including photon-production cross sections as well as energy and angular distributions of secondary photons. This faithful utilization of sophisticated ENDF/B evaluations allows more precise MCNP calculations for several classes of coupled neutron-photon problems

  9. New catalysts for photocatalytic cleaning of waste water; Neue Katalysatoren zur photokatalytischen Abwasserreinigung

    Energy Technology Data Exchange (ETDEWEB)

    Lindner, M [Inst. for Solarenergieforschung GmbH, Hannover (Germany); Bahnemann, D [Inst. for Solarenergieforschung GmbH, Hannover (Germany); Hirthe, B [Sachtleben Chemie, Duisburg (Germany); Griebler, W D [Sachtleben Chemie, Duisburg (Germany)

    1994-11-01

    Cleaning of polluted ground and waste water meets with particular problems where the group of halogenated hydrocarbons is concerned, which are not, or not readily, to be biologically degraded by conventional techniques. As an alternative technique to waste water cleaning, a method known as photocatalysis was proposed some years ago, which removes the organic pollutants by oxidation at semiconductor particles exposed to a light source. The article reports on a newly developed photocatalyst with distinctly enhanced pollutant degradation efficiency. (orig./EF) [Deutsch] Besondere Schwierigkeiten bei der Reinigung verschmutzter Grund- und Abwaesser bereitet die Gruppe der halogenierten Kohlenwasserstoffe, die sich nicht oder nur schwer auf herkoemmliche Weise biologisch abbauen lassen. Als alternative Technik zur Abwasserreinigung wurde vor einigen Jahren die sogenannte Photokatalyse vorgeschlagen, bei der die organischen Schadstoffe durch Oxidation an belichteten Halbleiterteilchen entfernt werden. Nachfolgend wird ueber einen neu entwickelten Photokatalysator berichtet, mit dessen Hilfe eine deutliche Steigerung der Effektivitaet des photokatalytischen Schadstoffabbaus gelingt. (orig./EF)

  10. Total balance of biogenic fuels for thermal uses; Ganzheitliche Bilanzierung verschiedener biogener Festbrennstoffe zur thermischen Nutzung

    Energy Technology Data Exchange (ETDEWEB)

    Becher, S.; Kaltschmitt, M. [Stuttgart Univ. (Germany). Inst. fuer Energiewirtschaft und Rationelle Energieanwendung (IER)

    1996-12-31

    In this situation of unfavourable energy price levels, the use of biogenic fuels for power supply can be recommended only if it serves to reduce environmental pollution. Against this background and on the basis of a primary energy balance, the authors attempted a total balance of selected enfironmental effects (global heating and acidification potential) of biomass use as compared to fossil fuel combustion. (orig) [Deutsch] ie Nutzung biogener Festbrennstoffe zur Energienachfragedeckung ist bei dem gegenwaertigen unguenstigen Energiepreisniveau nur dann zu rechtfertigen, wenn es durch die Biomassenutzung zu einer Reduzierung der energiebedingten Umwelteffekte kommt. Vor disem Hintergrund werden ausgehend von der Primaerenergiebilanz ausgewaehlte Umwelteffekte (d.h. das Treibhaus- und das Versauerungspotential) einer Biomassenutzung im Vergleich zu einer Nutzung fossiler Energietraeger ganzheitlich bilanziert. Die wesentlichen Ergebnisse werden zusammengefasst und interpretiert. (orig)

  11. Investigations of pollutant migration using lysimeters; Untersuchungen zur Schadstoff-Migration in Lysimetern

    Energy Technology Data Exchange (ETDEWEB)

    Klotz, D. (ed.)

    2002-07-01

    The third GSF Lysimeter Workshop focused on pollutant migration in underground strata, i.e. the dispersion of water constituents as referred to water transport on the basis of ideal tracer investigations. [German] Der am 29./30.04.2002 stattgefundene Workshop 'Untersuchungen zur Schadstoffmigration in Lysimetern' war der dritte GSF-Lysimeterworkshop nach denen in den Jahren 1998 und 2000 veranstalteten. Nachdem in den Jahren 1998 und 2000 der Wassertransport und die Bestimmung der Sickerwassergeschwindigkeit in Lysimetern im Mittelpunkt standen, war 2002 die Schadstoffmigration im Untergrund der Schwerpunkt der Vortraege und Poster. Unter Migration wird das Ausbreitungsverhalten von Wasserinhalts-(Fremd-, Schad-)Stoffen bezogen auf den Wassertransport, bestimmt mit idealen Tracern, verstanden. (orig.)

  12. Total balance of biogenic fuels for thermal uses; Ganzheitliche Bilanzierung verschiedener biogener Festbrennstoffe zur thermischen Nutzung

    Energy Technology Data Exchange (ETDEWEB)

    Becher, S; Kaltschmitt, M [Stuttgart Univ. (Germany). Inst. fuer Energiewirtschaft und Rationelle Energieanwendung (IER)

    1997-12-31

    In this situation of unfavourable energy price levels, the use of biogenic fuels for power supply can be recommended only if it serves to reduce environmental pollution. Against this background and on the basis of a primary energy balance, the authors attempted a total balance of selected enfironmental effects (global heating and acidification potential) of biomass use as compared to fossil fuel combustion. (orig) [Deutsch] ie Nutzung biogener Festbrennstoffe zur Energienachfragedeckung ist bei dem gegenwaertigen unguenstigen Energiepreisniveau nur dann zu rechtfertigen, wenn es durch die Biomassenutzung zu einer Reduzierung der energiebedingten Umwelteffekte kommt. Vor disem Hintergrund werden ausgehend von der Primaerenergiebilanz ausgewaehlte Umwelteffekte (d.h. das Treibhaus- und das Versauerungspotential) einer Biomassenutzung im Vergleich zu einer Nutzung fossiler Energietraeger ganzheitlich bilanziert. Die wesentlichen Ergebnisse werden zusammengefasst und interpretiert. (orig)

  13. Zur Rekonstruktion einer Typologie jugendlichen Medienhandelns gemäß dem Leitbild der Triangulation

    Directory of Open Access Journals (Sweden)

    Klaus Peter Treumann

    2017-09-01

    Full Text Available Die im Folgenden dargestellten Ergebnisse sind im Rahmen des von der DFG geförderten Forschungsprojekts „Eine Untersuchung zum Mediennutzungsverhalten 12- bis 20-Jähriger und zur Entwicklung von Medienkompetenz im Jugendalter“ entstanden, das gemeinsam von Klaus Peter Treumann, Uwe Sander und Dorothee Meister geleitet wird. Das Forschungsprojekt untersucht das Medienhandeln Jugendlicher sowohl hinsichtlich Neuer als auch alter Medien. Zum einen fragen wir dabei nach den Ausprägungen von Medienkompetenz in verschiedenen Dimensionen und zum anderen konzentrieren wir uns auf die Entwicklung einer empirisch fundierten Typologie jugendlichen Medienhandelns. Methodologisch ist die Untersuchung an dem Leitbild der Triangulation orientiert und kombiniert qualitative und quantitative Zugänge zum Forschungsfeld in Form von Gruppendiskussionen, leitfadengestützten Einzelinterviews und einer Repräsentativerhebung.

  14. Simulator to evaluate and optimise driver assistance systems; Ein Simulator zur Bewertung und Optimierung von Fahrerassistenzsystemen

    Energy Technology Data Exchange (ETDEWEB)

    Locher, J. [Hella KG Hueck and Co., Paderborn (Germany); Kleinkes, M. [Hella KG Hueck and Co., Lippstadt (Germany)

    2003-07-01

    For a short time now, the L-LAB (Light-LABoratory), a joint research facility of Hella KG and the University of Paderborn, has had a simulator available which allows the evaluation of driver assistance systems and the optimisation of man-machine interfaces. It is an interactive night driver simulator, which can be used to visualise any type of headlamp beam pattern true to the original. A Smart is used as the input medium; image projection is via a 3-channel high-performance beamer projection system onto large screens. Alongside synthetic roads, there is also a digitalised course available, approx. 10 km long, the original of which is actually used by Hella as a proving ground. Road safety indicators can be recorded directly and indirectly. For example, obstacles which suddenly appear force drivers to apply the brakes. The stopping distance required can be interpreted as a direct indicator for safety. In addition, an eye tracking system is used to record the eye movements of the test subjects, which allows additional road safety indicators to be derived. Comparative investigations between the digitalised proving ground and reality allow validation of the simulator. This year, a comprehensive study will be made to optimise the man-machine interface in connection with infrared vision systems in vehicles. The advantages of simulation are not only in the economical implementation possibilities and control of the variables, but also the fact that properties of driver assistance systems can be evaluated which are not even technically possible yet in reality. The use of the simulator developed here is not limited to tests connected with the visibility of obstacles, however. Rather, it allows the investigation and evaluation of a large range of potential driver assistance systems. (orig.) [German] Dem L-LAB (Light-LABoratory), einer gemeinsamen Forschungseinrichtung der Universitaet Paderborn und der Firma Hella KG in Lippstadt, steht seit kurzer Zeit ein Simulator zur

  15. Konsensus zur Anwendung der "Tension-free Vaginal Tape" (TVT Operation bei der weiblichen Belastungsinkontinenz

    Directory of Open Access Journals (Sweden)

    Hanzal E

    2003-01-01

    Full Text Available Unter der Patronanz der Medizinischen Gesellschaft für Inkontinenzhilfe Österreich wurde im Juni 2002 in Wien die 2. Auflage eines Österreichischen Tension-free Vaginal Tape (TVT Konsensus-Meetings abgehalten. TVT ist eine neue Operationstechnik zur Behandlung der weiblichen Stressharninkontinenz, die seit 1998 in Österreich eingesetzt wird. Im Rahmen des Treffens, an dem Experten aus den Fachbereichen Urologie und Gynäkologie teilnahmen, wurde die vorhandene Fachliteratur analysiert und ein Konsensus für die präoperative Abklärung, Durchführung und postoperative Verlaufskontrolle als Basis für eine laufende Qualitätsverbesserung des Verfahrens erarbeitet, dessen Ergebnis in dem vorliegenden Papier als Leitlinie zusammengefaßt ist.

  16. ENZIAN-Klassifikation zur Diskussion gestellt: Eine neue differenzierte Klassifikation der tief infiltrierenden Endometriose

    Directory of Open Access Journals (Sweden)

    Tuttlies F

    2008-01-01

    Full Text Available Mit Einführung des ENZIAN-Scores wurde eine neue Klassifikation für die Erkrankung der Endometriose vorgestellt, die insbesondere die tief infiltrierende Endometriose mit der typischen retroperitonealen Manifestation berücksichtigt. In Anlehnung an onkologische Stadieneinteilungen wurde eine Einteilung in vier Schweregrade gewählt, die mit drei Raumachsen zur Lokalisation der Erkrankung erweitert wurden. Der ENZIAN-Score versteht sich als eine Ergänzung zu dem bekannten rAFS-System (revised American Fertility and Sterility Score, das sich lediglich auf die intraperitoneale Manifestation der Endometriose anwenden lässt. In vielen Fällen ist die rAFS-Klassifikation nur bedingt oder gar nicht geeignet, die Ausdehnung und den Schweregrad der Erkrankung darzustellen. Am Kollektiv von Patientinnen mit Darmendometriose wurde der ENZIAN- Score retrospektiv auf die klinische Wertigkeit hin untersucht und bewährte sich in der klinischen Anwendung.

  17. Die „Leipziger schule”. Zur geschichte der kirchenmusik Im 20. jahrhundert

    Directory of Open Access Journals (Sweden)

    Loos Helmut

    2013-01-01

    Full Text Available Auf die Initiative Karls Straubes ging die Gründung des Instituts für Kirchenmusik am Leipziger Konservatorium im Jahre 1921 zurück. Zusammen mit seinem Meisterschüler Günther Ramin gestaltete er über lange Jahre hinweg die Kirchenmusik in St. Thomas. Nach dem Ende des Ersten Weltkriegs gewann die Bach-Bewegung für den Protestantismus eine zentrale Bedeutung, zumal sich Leipzig als richtungsweisendes Zentrum profilierte und mit der „Ära Straube-Ramin” eine „Leipziger Schule” ausbildete. Obwohl Straube und Ramin nicht selbst komponierten, war insbesondere ihr Wirken am Konservatorium der Musik zu Leipzig wesentlich für die Bildung der „Leipziger Schule” als Erneuerungsbewegung evangelischer Kirchenmusik. In dem Artikel wird das Schicksal dieser Bestrebungen und ihrer Protagonisten während der katastrophalen ökonomischen Umstände und des anwachsenden Nationalisozialismus analysiert.

  18. Formation of η' mesons in photon-photon collisions

    International Nuclear Information System (INIS)

    Uitert, B.K. van.

    1986-01-01

    This thesis describes an experiment performed at the positron electron storage ring PEP at the Stanford Linear Accelerator Center on the formation of the η' resonance which is observed in its decay mode ρ 0 γ, where the ρ decays into a π + π - pair. Some general features of the relatively new subject of photon-photon physics are introduced. The η' and the coupling of photons to the η' are discussed in the context of the quark model. It is shown how the mixing angle in the nonet of pseudoscalar mesons can be derived from ratios of γγ widths. The kinematics of the two-photon exchange process, the formation of the η' resonance by the two virtual photons and its subsequent electromagnetic decay into ρ 0 γ are discussed. The selected sample of events is used to determine the γγ width of the η' under the conventional assignment J P = 0 - for the η' and J P = 1 - for the ρ. The result is combined with measurements by other experiments to a world average, which is used to determine the mixing angle for the pseudoscalar nonet under various assumptions. The decay angular and energy distributions are investigated in detail. (Auth.)

  19. On the validity of the equivalent-photon approximation for virtual photon-photon collisions

    International Nuclear Information System (INIS)

    Carimalo, C.; Kessler, P.; Parisi, J.

    1979-05-01

    For virtual photon-photon collisions in electron storage rings, one derive the equivalent-photon approximation from a helicity treatment, and present it in two forms, involving respectively (i) polarized transverse photons ('transverse-photon approximation') and (ii) unpolarized ones ('Williams-Weizsaecker approximation'). One first postulates the conditions of validity of the approximation on the basis of analytic considerations, and then check them numerically in the case of the process e e → e e μ + μ - . For this check, we consider the completely differentiated cross section as far as approximation (i) is concerned; and in the case of approximation (ii), the cross section differentiated with respect to all variables except the azimuthal angles. The results are given in the form of Tables showing the lower and higher limit of the error involved in the approximation for a large variety of kinematic configurations (i. e., energy losses and scattering angles of both electrons). Those Tables are discussed in detail, and conclusions are drawn as to the applicability of the equivalent-photon approximation to future experiments to be performed with high-energy electron storage rings

  20. Invasive procedure for clarification of pulmonary nodules; Invasive Verfahren zur Abklaerung pulmonaler Rundherde

    Energy Technology Data Exchange (ETDEWEB)

    Mahnken, A.H. [Universitaetsklinikum, Philipps-Universitaet Marburg, Klinik fuer Diagnostische und Interventionelle Radiologie, Marburg (Germany)

    2014-05-15

    The management of solitary lung nodules poses a common clinical problem and biopsy is often required. Several guidelines provide slightly different recommendations and there are no uniform recommendations regarding the ideal technique of puncture guidance (e.g. percutaneous versus bronchoscopic or thoracoscopic). Fine needle aspiration biopsy (FNA) and core biopsy are well established techniques. Both can be performed under CT and to some extent ultrasound guidance. Diagnostic accuracies of FNA and core biopsy for malignant lesions are around 95 %. Core biopsy is superior to FNA for establishing a specific diagnosis with a diagnostic yield of 81-88 % versus 17-21 %. In clinical routine practice core biopsy is the superior tool when compared to FNA. Central lesions in close proximity to bronchi may be biopsied with endobronchial ultrasound (EBUS)-guided bronchoscopy. In all other lesions percutaneous, ideally CT-guided biopsy should be the method of first choice. (orig.) [German] Solitaere Lungenrundherde stellen ein haeufiges differenzialdiagnostisches Problem dar, das oftmals mit der Bildgebung alleine nicht endgueltig zu loesen ist und eine Biopsie erfordert. Die Indikation zur Biopsie variiert zwischen den Leitlinien, und die beste Technik der Biopsie (perkutan vs. bronchoskopisch vs. thorakoskopisch) ist oftmals nicht eindeutig. Feinnadelaspirations- (FNA) und Stanzbiopsie stehen als lange etablierte Standardtechniken zur Verfuegung. Beide koennen CT- und bedingt ultraschallgesteuert durchgefuehrt werden. Die diagnostische Aussagekraft fuer die Diagnose maligner Tumoren liegt fuer beide Techniken bei 95 %. Die Stanzbiopsie ist jedoch der FNA fuer die spezifische Diagnose benigner Prozesse mit einer Genauigkeit von 82-88 vs. 17-21 % ueberlegen. Die Stanzbiopsie ist gegenueber der FNA das in der klinischen Routine ueberlegene Werkzeug. Bei sehr zentralen Herden in Nachbarschaft zu einem Bronchus kann primaer eine bronchoskopische EBUS-gesteuerte (endobronchialer

  1. Vorschrift oder Thunfisch? – Zur Langzeitverfügbarkeit von Forschungsdaten

    Directory of Open Access Journals (Sweden)

    Tim Hasler

    2013-10-01

    Full Text Available Ich mache ihm ein Angebot, das er nicht ablehnen kann.” Diese Aussage aus einem gänzlich anderen Kontext lässt sich recht treffend übertragen als Wunsch von Dienstleistern und Zweck von Dienstleistungen für Datenproduzenten im Forschungsdatenmanagement. Zwar wirkt Druck zur Datenübergabe nicht förderlich, die Eröffnung einer Option aber sehr wohl. Im vorliegenden Artikel geht es um das Verständnis der Nachhaltigkeit von Forschung und ihren Daten anhand der Erkenntnisse und Erfahrungen aus der ersten Phase des DFG-Projekts EWIG. [Fn 01] Eine Auswahl von Fallstricken beim Forschungsdatenmanagement wird anhand der Erkenntnisse aus Expertengesprächen und eigenen Erfahrungen beim Aufbau von LZA-Workflows vorgestellt. Erste Konzepte in EWIG zur Datenübertragung aus unterschiedlich strukturierten Datenquellen in die „Langfristige Domäne” werden beschrieben. "I'm gonna make him an offer he can't refuse". This quote from a completely different context can be aptly rendered as a statement of service providers as well as the purpose of services for data producers in the field of research data management. Although pressure is not the leverage of choice if you want researchers to deposit their research data in some kind of repository, offering an option does the trick quite well. In this article we present some of the concepts for sustainability of research and its data from the first phase the of the project EWIG, funded by the Deutsche Forschungsgemeinschaft. A selection of pitfalls in research data management is presented based on the findings from expert interviews and our own experiences in the construction of LTP workflows. First concepts in EWIG to transfer data from differently structured data sources into the "Permanent Domain" are described.

  2. Lehrerkooperation: theoretische reflexion über voraussetzungen zur erweiterung von kooperativität bei lehrern

    Directory of Open Access Journals (Sweden)

    Rainer Lengert

    2012-01-01

    Full Text Available Viele Bildungseinrichtungen verfolgen den Ausbau der Zusammenarbeit zwischen Lehrern, mit der Absicht, das Arbeitsklima zu pflegen und vor allem zur Verbesserung der Qualität ihres Bildungsangebotes. Allerdings bereiten die kooperativen Initiativen oft Unannehmlichkeiten, es sei denn, die Beteiligten kennen die umfangreichen Hintergründe, die höhere oder mindere Ebenen von Kooperation erleichtern oder behindern können. Diese Lücke wird im vorliegenden Artikel abgehandelt, indem neun Prämissen als Voraussetzung zur Erweiterung der Kooperation zwischen Lehrern dargestellt werden. Im Bewusstsein dieser Prämissen, ist es möglich, empirische Erforschungen künftig zu instrumentalisieren, wie auch Wege zu schaffen, Anforderungen an Lehrer und Schulen gewisser zu verwalten.Abstract Muitas instituições escolares têm aderido à busca de ampliar a cooperação entre seus professores, com a intenção de cuidar do ambiente de trabalho, mas, principalmente, de melhorar a qualidade de ensino oferecida. Porém, as iniciativas cooperativas costumam enfrentar dificuldades, sem que os envolvidos tenham conhecimento das causas amplas que impedem ou facilitam maiores ou menores níveis de cooperação. É dessa lacuna que trata o presente artigo, discutindo nove premissas que subjazem à possibilidade de ampliar a cooperação entre professores. Tendo consciência das premissas, é possível instrumentalizar futuras pesquisas empíricas, como também criar meios de gerir os requisitos que são de responsabilidade dos professores e das instituições escolares.

  3. Ein kombinierter Operationsansatz zur Therapie der rektovaginalen Endometriose auf der Basis histologischer Befunde

    Directory of Open Access Journals (Sweden)

    Köhler C

    2008-01-01

    Full Text Available Einleitung: Eine Endometriose des Septum rectovaginale kann oberflächlich dem Darm aufliegen oder die Darmwand infiltrieren. Durch bildgebende Verfahren kann jedoch präoperativ eine Infiltration des Darms weder hinreichend bestätigt noch ausgeschlossen werden, was zu einem therapeutischen Dilemma führt, da nur die Darmwand eindeutig infiltrierende Endometrioseprozesse durch eine Darmresektion behandelt werden sollten. Wir möchten ein neues Operationsverfahren vorstellen, das eine intraoperative Differenzierung zwischen einer oberflächlichen und einer infiltrativen Darmendometriose erlaubt. Patienten und Methodik: 70 Patientinnen mit rektovaginaler Endometriose wurden nach einem neu entwickelten kombinierten vaginal-laparoskopisch-abdominalen Verfahren operiert. Diese Operationsmethode wird Schritt für Schritt vorgestellt. Die Entscheidung zur Darmresektion wurde dabei allein aufgrund der intraoperativen Befunde und nicht aufgrund der präoperativen bildgebenden Diagnostik getroffen. Alle Resektate wurden standardisiert histologisch aufgearbeitet. Ergebnisse: Ob eine Darmresektion notwendig war, ließ sich intraoperativ anhand der Präparation des rektovaginalen Septums entscheiden. Daher wurden nur bei Patientinnen mit gesichertem infiltrativem Darmbefall Darmresektionen unter Erhalt des Mesointestinums durchgeführt. Weder intraoperative noch postoperative Komplikationen wie Anastomoseninsuffizienzen oder Restharnmengen traten auf. Diskussion: Die vorgestellte Operationsmethode zur Therapie der rektovaginalen Endometriose erlaubt eine exakte Diagnosestellung und präzise Therapieentscheidung bei minimaler Morbidität. Die Resektion des Darmschlauches ohne Mesoresektion ist ausreichend, da sich die Endometrioseknoten – wie histologisch bewiesen wurde – nur im ventralen Darmbereich befinden. Durch die Mesoerhaltung werden die vegetativen Funktionen des kleinen Beckens nicht beeinträchtigt.

  4. PHOTON09. Proceedings of the international conference on the structure and interactions of the photon including the 18th international workshop on photon-photon collisions and the international workshop on high energy photon linear colliders

    Energy Technology Data Exchange (ETDEWEB)

    Behnke, Olaf; Diehl, Markus; Schoerner-Sadenius, Thomas; Steinbrueck, Georg [eds.

    2010-01-15

    The following topics were dealt with: Electroweak and new physics, photon-collider technology, low-energy photon experiments, prompt photons, photon structure, jets and heavy flavours, vacuum polarization and light-by-light scattering, small-x processes, diffraction, total cross sections, exclusive channels and resonances, photons in astroparticle physics. (HSI)

  5. PHOTON09. Proceedings of the international conference on the structure and interactions of the photon including the 18th international workshop on photon-photon collisions and the international workshop on high energy photon linear colliders

    International Nuclear Information System (INIS)

    Behnke, Olaf; Diehl, Markus; Schoerner-Sadenius, Thomas; Steinbrueck, Georg

    2010-01-01

    The following topics were dealt with: Electroweak and new physics, photon-collider technology, low-energy photon experiments, prompt photons, photon structure, jets and heavy flavours, vacuum polarization and light-by-light scattering, small-x processes, diffraction, total cross sections, exclusive channels and resonances, photons in astroparticle physics. (HSI)

  6. Silicon photonics: some remaining challenges

    Science.gov (United States)

    Reed, G. T.; Topley, R.; Khokhar, A. Z.; Thompson, D. J.; Stanković, S.; Reynolds, S.; Chen, X.; Soper, N.; Mitchell, C. J.; Hu, Y.; Shen, L.; Martinez-Jimenez, G.; Healy, N.; Mailis, S.; Peacock, A. C.; Nedeljkovic, M.; Gardes, F. Y.; Soler Penades, J.; Alonso-Ramos, C.; Ortega-Monux, A.; Wanguemert-Perez, G.; Molina-Fernandez, I.; Cheben, P.; Mashanovich, G. Z.

    2016-03-01

    This paper discusses some of the remaining challenges for silicon photonics, and how we at Southampton University have approached some of them. Despite phenomenal advances in the field of Silicon Photonics, there are a number of areas that still require development. For short to medium reach applications, there is a need to improve the power consumption of photonic circuits such that inter-chip, and perhaps intra-chip applications are viable. This means that yet smaller devices are required as well as thermally stable devices, and multiple wavelength channels. In turn this demands smaller, more efficient modulators, athermal circuits, and improved wavelength division multiplexers. The debate continues as to whether on-chip lasers are necessary for all applications, but an efficient low cost laser would benefit many applications. Multi-layer photonics offers the possibility of increasing the complexity and effectiveness of a given area of chip real estate, but it is a demanding challenge. Low cost packaging (in particular, passive alignment of fibre to waveguide), and effective wafer scale testing strategies, are also essential for mass market applications. Whilst solutions to these challenges would enhance most applications, a derivative technology is emerging, that of Mid Infra-Red (MIR) silicon photonics. This field will build on existing developments, but will require key enhancements to facilitate functionality at longer wavelengths. In common with mainstream silicon photonics, significant developments have been made, but there is still much left to do. Here we summarise some of our recent work towards wafer scale testing, passive alignment, multiplexing, and MIR silicon photonics technology.

  7. Photonics Research and Development

    Energy Technology Data Exchange (ETDEWEB)

    Dickson, Elizabeth [UNLV Research Foundation, Las Vegas, NV (United States)

    2010-01-15

    During the period August 2005 through October 2009, the UNLV Research Foundation (UNLVRF), a non-profit affiliate of the University of Nevada, Las Vegas (UNLV), in collaboration with UNLV's Colleges of Science and Engineering; Boston University (BU); Oak Ridge National Laboratory (ORNL); and Sunlight Direct, LLC, has managed and conducted a diverse and comprehensive research and development program focused on light-emitting diode (LED) technologies that provide significantly improved characteristics for lighting and display applications. This final technical report provides detailed information on the nature of the tasks, the results of the research, and the deliverables. It is estimated that about five percent of the energy used in the nation is for lighting homes, buildings and streets, accounting for some 25 percent of the average home's electric bill. However, the figure is significantly higher for the commercial sector. About 60 percent of the electricity for businesses is for lighting. Thus replacement of current lighting with solid-state lighting technology has the potential to significantly reduce this nation's energy consumption by some estimates, possibly as high as 20%. The primary objective of this multi-year R&D project has been to develop and advance lighting technologies to improve national energy conversion efficiencies; reduce heat load; and significantly lower the cost of conventional lighting technologies. The UNLVRF and its partners have specifically focused these talents on (1) improving LED technologies; (2) optimizing hybrid solar lighting, a technology which potentially offers the benefits of blending natural with artificial lighting systems, thus improving energy efficiency; and (3) building a comprehensive academic infrastructure within UNLV which concentrates on photonics R&D. Task researchers have reported impressive progress in (1) the development of quantum dot laser emitting diodes (QDLEDs) which will ultimately improve

  8. Plan de empresa para la creación de un restaurante de comida casual argentina Punta Zur

    OpenAIRE

    Arango B., Gustavo Adolfo; Isaacs, Laura

    2011-01-01

    RESUMEN: Punta Zur, será un restaurante de comida casual dentro de la categoría de comida rápida, ubicado en Granada, Cali, que iniciará operaciones en Mayo de 2012. Los productos ofrecidos serán platos típicos del sur del continente americano, entre ellos el choripán y las brochetas (res, cerdo y pollo). También se ofrecerán acompañantes tales como papas, yucas fritas, chips de plátano y bebidas como jugos naturales, gaseosas y cervezas. En Punta Zur los clientes encontrarán un sitio en el q...

  9. Enhanced axion-photon coupling in GUT with hidden photon

    Science.gov (United States)

    Daido, Ryuji; Takahashi, Fuminobu; Yokozaki, Norimi

    2018-05-01

    We show that the axion coupling to photons can be enhanced in simple models with a single Peccei-Quinn field, if the gauge coupling unification is realized by a large kinetic mixing χ = O (0.1) between hypercharge and unbroken hidden U(1)H. The key observation is that the U(1)H gauge coupling should be rather strong to induce such large kinetic mixing, leading to enhanced contributions of hidden matter fields to the electromagnetic anomaly. We find that the axion-photon coupling is enhanced by about a factor of 10-100 with respect to the GUT-axion models with E / N = 8 / 3.

  10. Photon statistics characterization of a single-photon source

    International Nuclear Information System (INIS)

    Alleaume, R; Treussart, F; Courty, J-M; Roch, J-F

    2004-01-01

    In a recent experiment, we reported the time-domain intensity noise measurement of a single-photon source relying on single-molecule fluorescence control. In this paper, we present data processing starting from photocount timestamps. The theoretical analytical expression of the time-dependent Mandel parameter Q(T) of an intermittent single-photon source is derived from ON↔OFF dynamics. Finally, source intensity noise analysis, using the Mandel parameter, is quantitatively compared with the usual approach relying on the time autocorrelation function, both methods yielding the same molecular dynamical parameters

  11. Untersuchungen zur Involution der Vagina and Zervix beim Rind post partum unter Berücksichtigung der Zervix als Geburtshindernis

    OpenAIRE

    Wehrend, Axel

    2002-01-01

    Ziel der vorliegenden Arbeit war es die physiologische Involution der Zervix im Vergleich zur Vagina beim Rind während der ersten zehn Tage post partum zu charakterisieren. Weiterhin sollte durch klinische Untersuchungen an Kühen nach Dystokie und einer retrospektiven Datenauswertung von Schwergeburten unterschiedlicher Tierarten der Anteil zervikal bedingter Geburtsstockungen im Interspeziesvergleich analysiert und Einflussfaktoren auf das Auftreten dieser Dystokieform sowie Störungen in der...

  12. Neue numerische Methoden zur Bearbeitung und 3D-Interpretation von Geodaten und -modellen in interdisziplinärer Forschung

    OpenAIRE

    Menzel, Peter

    2016-01-01

    In dieser Arbeit wird gezeigt, wie Ansätze und Verfahren aus der Geoinformatik die Prozessierung und Interpretation von Daten in der Geophysik, speziell der Potentialverfahren unterstützen. Im Rahmen des BMBF-Verbundprojekts AIDA wurde für ein Untersuchungsgebiet in Norddeutschland ein 3D Untergrundmodell entwickelt. Hier wird gezeigt, wie die Modellgeometrie für die Schweremodellierung aufbereitet wurde. Anschließend wird ein hier entwickeltes Verfahren zur statistischen Abschätzung un...

  13. Zur Ätiologie und Bekämpfung der Lumpy Jaw Disease bei Kängurus

    OpenAIRE

    Asperger, Michael

    2004-01-01

    In der vorliegenden Arbeit sollten die in der veterinärmedizinischen Literatur bisher diskutierten Ursachen für LJD bei Makropoden hinsichtlich ihrer tatsächlichen Bedeutung abgeklärt und die Eignung einer formalininaktivierten, bestandsspezifischen Adsorbatvakzine zur Prophylaxe von LJD getestet werden. Da LJD eine parodontale Erkrankung darstellt, wurden auch die für Entstehung einer humanen Parodontitis prädisponierenden Faktoren mit in die Untersuchung einbezogen. Es wurden Tupferproben z...

  14. Furane, Furanone und Pyranone – ihr Beitrag zur Farbe und den antioxidativen Eigenschaften in der Maillard-Reaktion der Maltose

    OpenAIRE

    Kanzler, Clemens

    2017-01-01

    Die Maillard-Reaktion ist dafür bekannt, bei der thermischen Behandlung von Lebensmitteln neben deren organoleptischen Eigenschaften, wie Geschmack, Geruch, Textur und Farbe, auch die oxidative Stabilität zu beeinflussen. Letzteres ist auf die Bildung von komplexierenden und reduzierenden Verbindungen zurückzuführen, die antioxidativ und prooxidativ wirken können. Im Rahmen der vorliegenden Arbeit werden die antioxidativen Kapazitäten von dreizehn Maillard-Reaktionsintermediaten mit Furan-...

  15. Practical guide to more efficient use of energy in industry; Praxisleitfaden zur Foerderung der rationellen Energieverwendung in der Industrie

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-09-04

    Starting with an easily digestible explanation of fundamental concepts and terms in the field of energy and its applications, as well as the related thermodynamic principles and processes, the second chapter explains the system of energy and exergy. Chapters 3 and 4 give a comprehensive picture of current technologies and processes in energy generation and engineering, from energy applications for process heat generation through to power plants and combined and heat and power systems, fuel cells and energy generation from renewable primary sources, discussing related aspects of interest such as energy and pollutant emissions, and economic aspects. Chapter 5 is devoted to counselling and guidance for corporate energy engineering analysis and enhancement. Chapters 6 and 7 round up the comprehensive information addressing the legal aspects of procedures for licensing of energy generation and conversion systems, and the various financing instruments and schemes available for projects intended to promote more efficient use of energy. (orig./CB) [Deutsch] Ausgehend von einer anschaulichen Beschreibung grundlegender Energiebegriffe und thermodynamischer Zusammenhaenge wird im zweiten Kapitel in klarer Weise das Zusammenspiel zwischen Energie und Exergie dargestellt. Aufbauend auf diesen grundlegenden Hinweisen bieten die Kapitel 3 und 4 eine weitreichende Uebersicht der gegenwaertig zur Verfuegung stehenden Prozess- und Energietechniken. Ausgehend von Techniken zur Prozesswaermebereitstellung spannt sich der Bogen ueber Kraftanlagen und Kraft-Waerme-Kopplungssysteme bis hin zu Brennstoffzellen und regenerativen Energietechniken, wobei der Schwerpunkt der Betrachtungen auf Energie- und Emissionsaspekte sowie wirtschaftliche Randbedingungen gelegt wurde. Kapitel 5 gibt Hinweise zur Vorbereitung und Durchfuehrung energietechnischer Beratungen und Analysen auf betrieblicher Ebene. Im Anschluss an den technischen Teil dieses Leitfadens folgt in Kapitel 6 eine Erlaeuterung der

  16. Freilanduntersuchungen zur Ökologie und zum Verhalten von Trachypithecus auratus kohlbruggei (Haubenlanguren) im West-Bali-Nationalpark, Indonesien

    OpenAIRE

    Vogt, Martina

    2003-01-01

    Languren gehören zu den asiatischen Schlankaffen, die zusammen mit den afrikanischen Stummelaffen die Unterfamilie Colobinae, neben den Cercopithecinae die zweite rezente Gruppe der Cercopithecoidea, bilden. Während heute über viele Vertreter der Cercopithecinae zahlreiche Langzeitstudien zu verschiedenen Jahreszeiten und in unterschiedlichen Habitaten vorliegen, ist über die Biologie der Colobinae noch vergleichsweise wenig bekannt. Die Kenntnisse zur Lebensweise vieler Schlank- und Stummela...

  17. Zur Aktualität der identitären Ideologie : die Vordenker einer neuen rechten Internationale

    OpenAIRE

    Brumlik, Micha

    2017-01-01

    Rechtspopulistische Bewegungen machen sich zur Zeit in vielen westlichen Staaten zum Sprachrohr angeblich bisher unterdrückter Bevölkerungsgruppen und Meinungen. Die identitäre Bewegung entwickelt diesen Ansatz weiter zu einem Projekt der autoritären Staatlichkeit gegen Multikulturalismus, Islam und Einwanderung. Dabei verbindet sie ihre Kampagne für einen ethnisch geschlossen Nationalstaat mit der Kritik an der kapitalistischen Globalisierung. Mit einem Sprachduktus, der Politik emotionalisi...

  18. Paediatric Virology as a new educational initiative: An interview with Nobelist Professor of Virology Harald zur Hausen.

    Science.gov (United States)

    Mammas, Ioannis N; Spandidos, Demetrios A

    2017-10-01

    Born in Gelsenkirchen-Buer in Germany on March 11th, 1936, Professor Harald zur Hausen, Emeritus Professor of Virology at the University of Freiburg and 2008 Nobel Prize Laureate in Physiology or Medicine for his discovery of human papillomavirus (HPV), which causes cervical cancer, believes that good knowledge of virological methods and diagnostic possibilities are an asset for all young paediatricians. Professor zur Hausen considers that the creation of an educational platform on Paediatric Virology is definitely very beneficial for young paediatricians, as this will greatly enhance their knowledge in the field of Virology. He very actively advocates the vaccination of boys for the eradication of HPV infection and emphasises that male HPV vaccination should be included into the current vaccination programmes. He would have certainly considered Dr George N. Papanicolaou (Kyme, Island of Euboea, Greece, 1883 - Miami, Florida, USA, 1962) as an excellent candidate for the Nobel Prize, stating that the contribution of Dr Papanicolaou did not find sufficient recognition in the past. In the context of the 3rd Workshop on Paediatric Virology, which will be held in Athens, Greece, on October 7th, 2017, Professor zur Hausen will give his plenary lecture on 'Paediatric Virology and Oncology: Virus persistence and the important first years of life'.

  19. The potentials of spiral CT for detection of focal liver lesions; Moeglichkeiten der Spiral-CT zur Diagnostik fokaler Leberlaesionen

    Energy Technology Data Exchange (ETDEWEB)

    Helmberger, H. [Technische Univ. Muenchen, Klinikum rechts der Iser, Inst. fuer Roentgendiagnostik (Germany); Kersting-Sommerhoff, B. [Technische Univ. Muenchen, Klinikum rechts der Iser, Inst. fuer Roentgendiagnostik (Germany); Lenz, M. [Technische Univ. Muenchen, Klinikum rechts der Iser, Inst. fuer Roentgendiagnostik (Germany); Kirsten, R. [Technische Univ. Muenchen, Klinikum rechts der Iser, Inst. fuer Roentgendiagnostik (Germany); Bautz, W. [Technische Univ. Muenchen, Klinikum rechts der Iser, Inst. fuer Roentgendiagnostik (Germany)

    1996-03-01

    Spiral CT currently is the modality of choice for all aspects of diagnostic evaluation of the liver. Optimal selection of treatment should be based inter alia on the findings obtained by spiral CT with arterial application of contrast medium, as for example S-CTA (primary liver tumors), or S-CTAP (secondary liver tumors). Ultrasonography is the major supplementing modality. In the near future, MR imaging applying liver-specific contrast-enhancing agents is expected to become an important competing technique, and further developments of interest in diagnostic imaging of the liver are in the offing: it is not yet known which technique will be the modality of choice at the onset of the 21st century. (orig.) [Deutsch] Die Spiral-CT ist zur Zeit das empfehlenswerte Verfahren fuer alle Fragen der Leberdiagnostik. Zur optimalen praetherapeutischen Beurteilung der Leber sollte die Spiral-CT mit arterieller Kontrastmittelapplikation als S-CTA (primaere Lebertumoren) bzw. S-CTAP (sekundaere Lebertumoren) durchgefuehrt werden. Der US kommt ein Stellenwert als ergaenzende Methode zu. In Zukunft wird die MRT mit leberspezifischen Kontrastmitteln ein konkurrierendes Verfahren zur Spiral-CT darstellen, wobei eine weitere interessante Entwicklung auf dem Gebiet der hepatischen Bildgebung zu erwarten ist: Das diagnostische Verfahren der Wahl fuer die Leber zu Beginn des 21. Jahrhunderts ist noch nicht definiert. (orig.)

  20. An algorithm for calculating unsteady flow with free surface; Ein Verfahren zur Berechnung instationaerer Stroemungen mit freier Oberflaeche

    Energy Technology Data Exchange (ETDEWEB)

    Janetzky, B.

    2001-07-01

    A numerical model for the transient, free surface flow is implemented in a Finite-Element program for the unsteady calculation of incompressible flow with free surface. The program is used to calculate the flow in different components of a hydraulic turbine, the Pelton turbine. The movement of the fluid with free surface is described mathematically by introducing a partial differential equation for the volume fraction. This equation is simply a transport equation for f, i.e. the volume fraction is advected with the flow in time. The equations is solved numerically. (orig.) [German] Es wird ein Verfahren zur Modellierung von veraenderlichen, freien Oberflaechen vorgestellt und in einem Finite-Elemente-Programm zur numerischen Berechnung von instationaeren, inkompressiblen Stroemungen implementiert. Die veraenderliche, freie Oberflaeche wird mit einem Volume-Of-Fluid Ansatz erfasst. Zur Approximierung der freien Oberflaeche werden stueckweise konstante oder gestufte Verlaeufe im Element angesetzt. Es werden die Eigenschaften des Verfahrens an ausgewaehlten Beispielen mit freier Oberflaeche untersucht. Das erweiterte Programm wird auf instationaere Stroemungen mit freier Oberflaeche in einer hydraulischen Maschine, der Peltonturbine, angewandt. (orig.)

  1. Entangled photons and quantum communication

    Energy Technology Data Exchange (ETDEWEB)

    Yuan Zhensheng, E-mail: yuanzs@ustc.edu.c [Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China); Physikalisches Institut, Universitaet Heidelberg, Philosophenweg 12, 69120 Heidelberg (Germany); Bao Xiaohui [Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China); Physikalisches Institut, Universitaet Heidelberg, Philosophenweg 12, 69120 Heidelberg (Germany); Lu Chaoyang; Zhang Jun; Peng Chengzhi [Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China); Pan Jianwei, E-mail: pan@ustc.edu.c [Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China); Physikalisches Institut, Universitaet Heidelberg, Philosophenweg 12, 69120 Heidelberg (Germany)

    2010-12-15

    This article reviews the progress of quantum communication that utilizes photonic entanglement. We start with a survey of various methods for generating entangled photons, followed by an introduction of the theoretical principles and the experimental implementations of quantum key distribution. We then move on to a discussion of more involved quantum communication protocols including quantum dense coding, teleportation and quantum communication complexity. After that, we review the progress in free-space quantum communication, decoherence-free subspace, and quantum repeater protocols which are essential ingredients for long-distance quantum communication. Practical realizations of quantum repeaters, which require an interface between photons and quantum memories, are discussed briefly. Finally, we draw concluding remarks considering the technical challenges, and put forward an outlook on further developments of this field.

  2. Photonic quantum technologies (Presentation Recording)

    Science.gov (United States)

    O'Brien, Jeremy L.

    2015-09-01

    The impact of quantum technology will be profound and far-reaching: secure communication networks for consumers, corporations and government; precision sensors for biomedical technology and environmental monitoring; quantum simulators for the design of new materials, pharmaceuticals and clean energy devices; and ultra-powerful quantum computers for addressing otherwise impossibly large datasets for machine learning and artificial intelligence applications. However, engineering quantum systems and controlling them is an immense technological challenge: they are inherently fragile; and information extracted from a quantum system necessarily disturbs the system itself. Of the various approaches to quantum technologies, photons are particularly appealing for their low-noise properties and ease of manipulation at the single qubit level. We have developed an integrated waveguide approach to photonic quantum circuits for high performance, miniaturization and scalability. We will described our latest progress in generating, manipulating and interacting single photons in waveguide circuits on silicon chips.

  3. Photon Factory activity report, 1991

    International Nuclear Information System (INIS)

    1992-01-01

    The Photon Factory is a national synchrotron radiation research facility affiliated with the National Laboratory for High Energy Physics located in Tsukuba Science City. The Photon Factory consists of a 2.5 GeV electron/positron linear accelerator, a 2.5 GeV electron/positron storage ring, beam lines and experimental stations. All the facilities for synchrotron radiation research are open to scientists. A part of the accumulation ring of the TRISTAN main ring has been used as a synchrotron radiation source in the energy range from 5.8 to 6.5 GeV. The Photon Factory is composed of three divisions of Injector Linac, Light Source and Instrumentation. The researches of each divisions are reviewed, and the users' short reports are collected. The list of published papers with author index is also included in the publication. (K.I.) 233 refs

  4. Quenching effects in photon production

    International Nuclear Information System (INIS)

    Durand, M.

    1989-01-01

    Contraints on the photon production calculated by kinetic approaches are studied by means of sum-rules a finite temperature for simple quantum system. For the square-well potential the exact production rate is compared with its semi-classical limit in order to introduce the principle problem. For the scattering of hard spheres the photon production cross section is derived exactly by partial wave expansion. This serves to study the more realistic example of a gas of hard spheres. The corresponding kinetic photon production rates are found to violate the sum-rules, due to a singular behaviour at small gamma energies. Thus the hypothesis of incoherent free scattering is not valid in that range because of destructive interferences which quench the production rates significantly. For the application to nuclear collisions at intermediate energies these quenching effects are found to be important for gamma energies even up to a few hundred MeV. (orig.)

  5. Quantum photonics hybrid integration platform

    Energy Technology Data Exchange (ETDEWEB)

    Murray, E.; Floether, F. F. [Cambridge Research Laboratory, Toshiba Research Europe Limited, 208 Science Park, Milton Road, Cambridge CB4 0GZ (United Kingdom); Cavendish Laboratory, University of Cambridge, J.J. Thomson Avenue, Cambridge CB3 0HE (United Kingdom); Ellis, D. J. P.; Meany, T.; Bennett, A. J., E-mail: anthony.bennet@crl.toshiba.co.uk; Shields, A. J. [Cambridge Research Laboratory, Toshiba Research Europe Limited, 208 Science Park, Milton Road, Cambridge CB4 0GZ (United Kingdom); Lee, J. P. [Cambridge Research Laboratory, Toshiba Research Europe Limited, 208 Science Park, Milton Road, Cambridge CB4 0GZ (United Kingdom); Engineering Department, University of Cambridge, 9 J. J. Thomson Avenue, Cambridge CB3 0FA (United Kingdom); Griffiths, J. P.; Jones, G. A. C.; Farrer, I.; Ritchie, D. A. [Cavendish Laboratory, University of Cambridge, J.J. Thomson Avenue, Cambridge CB3 0HE (United Kingdom)

    2015-10-26

    Fundamental to integrated photonic quantum computing is an on-chip method for routing and modulating quantum light emission. We demonstrate a hybrid integration platform consisting of arbitrarily designed waveguide circuits and single-photon sources. InAs quantum dots (QD) embedded in GaAs are bonded to a SiON waveguide chip such that the QD emission is coupled to the waveguide mode. The waveguides are SiON core embedded in a SiO{sub 2} cladding. A tuneable Mach Zehnder interferometer (MZI) modulates the emission between two output ports and can act as a path-encoded qubit preparation device. The single-photon nature of the emission was verified using the on-chip MZI as a beamsplitter in a Hanbury Brown and Twiss measurement.

  6. Integrated Ultrasonic-Photonic Devices

    DEFF Research Database (Denmark)

    Barretto, Elaine Cristina Saraiva

    in channel waveguides and Mach-Zehnder interferometers. Numerical models are developed based on the finite element method, and applied to several scenarios, such as optimization of the geometrical parameters of waveguides, use of slow light in photonic crystal waveguides and use of Lamb waves in membranized......This thesis deals with the modeling, design, fabrication and characterization of integrated ultrasonic-photonic devices, with particular focus on the use of standard semiconductor materials such as GaAs and silicon. The devices are based on the use of guided acoustic waves to modulate the light...... investigated. Comparisons are made with the numerical and experimental results, and they validate the obtained response of the acoustic and photonic components of the device. Finally, a new design for an optical frequency shifter is proposed, posing several advantages over existing devices in terms of size...

  7. Single-photon decision maker

    Science.gov (United States)

    Naruse, Makoto; Berthel, Martin; Drezet, Aurélien; Huant, Serge; Aono, Masashi; Hori, Hirokazu; Kim, Song-Ju

    2015-08-01

    Decision making is critical in our daily lives and for society in general and is finding evermore practical applications in information and communication technologies. Herein, we demonstrate experimentally that single photons can be used to make decisions in uncertain, dynamically changing environments. Using a nitrogen-vacancy in a nanodiamond as a single-photon source, we demonstrate the decision-making capability by solving the multi-armed bandit problem. This capability is directly and immediately associated with single-photon detection in the proposed architecture, leading to adequate and adaptive autonomous decision making. This study makes it possible to create systems that benefit from the quantum nature of light to perform practical and vital intelligent functions.

  8. Photon attenuation by intensifying screens

    International Nuclear Information System (INIS)

    Holje, G.

    1983-01-01

    The photon attenuation by intensifying screens of different chemical composition has been determined. The attenuation of photons between 20 keV and 120 keV was measured by use of a multi-channel analyzer and a broad bremsstrahlung distribution. The attenuation by the intensifying screens was hereby determined simultaneously at many different monoenergetic photon energies. Experimentally determined attenuations were found to agree well with attenuation calculated from mass attenuation coefficients. The attenuation by the screens was also determined at various bremsstrahlung distributions, simulating those occurring behind the patient in various diagnostic X-ray examinations. The high attenuation in some of the intensifying screens form the basis for an analysis of the construction of asymmetric screen pairs. Single screen systems are suggested as a favourable alternative to thick screen pair systems. (Author)

  9. Optical properties of photonic crystals

    CERN Document Server

    Sakoda, Kazuaki

    2001-01-01

    The interaction between the radiation field and matter is the most fundamen­ tal source of dynamics in nature. It brings about the absorption and emission of photons, elastic and inelastic light scattering, the radiative lifetime of elec­ tronic excited states, and so on. The huge amount of energy carried from the sun by photons is the source of all activities of creatures on the earth. The absorption of photons by chlorophylls and the successive electronic excita­ tion initiate a series of chemical reactions that are known as photosynthesis, which support all life on the earth. Radiative energy is also the main source of all meteorological phenomena. The fundamentals of the radiation field and its interaction with matter were clarified by classical electromagnetism and quantum electrodynamics. These theories, we believe, explain all electromagnetic phenomena. They not only provide a firm basis for contemporary physics but also generate a vast range of technological applications. These include television, ...

  10. Review of dark photon searches

    International Nuclear Information System (INIS)

    Denig, Achim

    2016-01-01

    Dark Photons are hypothetical extra-U(1) gauge bosons, which are motivated by a number of astrophysical anomalies as well as the presently seen deviation between the Standard Model prediction and the direct measurement of the anomalous magnetic moment of the muon, (g − 2)μ. The Dark Photon does not serve as the Dark Matter particle itself, but acts as a messenger particle of a hypothetical Dark Sector with residual interaction to the Standard Model. We review recent Dark Photon searches, which were carried out in a global effort at various hadron and particle physics facilities. We also comment on the perspectives for future invisble searches, which directly probe the existence of Light Dark Matter particles.

  11. Entangled photons and quantum communication

    International Nuclear Information System (INIS)

    Yuan Zhensheng; Bao Xiaohui; Lu Chaoyang; Zhang Jun; Peng Chengzhi; Pan Jianwei

    2010-01-01

    This article reviews the progress of quantum communication that utilizes photonic entanglement. We start with a survey of various methods for generating entangled photons, followed by an introduction of the theoretical principles and the experimental implementations of quantum key distribution. We then move on to a discussion of more involved quantum communication protocols including quantum dense coding, teleportation and quantum communication complexity. After that, we review the progress in free-space quantum communication, decoherence-free subspace, and quantum repeater protocols which are essential ingredients for long-distance quantum communication. Practical realizations of quantum repeaters, which require an interface between photons and quantum memories, are discussed briefly. Finally, we draw concluding remarks considering the technical challenges, and put forward an outlook on further developments of this field.

  12. Research summer camp in photonics

    Science.gov (United States)

    Buyanovskaya, Elizaveta; Melnik, Maksim; Egorov, Vladimir; Gleim, Artur; Lukishova, Svetlana; Kozlov, Sergei; Zhang, Xi-Cheng

    2017-08-01

    ITMO University and the University of Rochester became close partners several years ago. One of the first outcomes of this mutually beneficial partnership was the creation of International Institute of Photonics and Optical Information Technologies led by Prof. Sergei Kozlov and Prof. Xi-Cheng Zhang. Universities have created a double Masters-degree program in optics in 2014, and several ITMO students have been awarded degrees from Rochester. At the same time ITMO University organizes Summer Research camp in Photonics for University of Rochester students. Students spent two weeks in the Northern Capital of Russia learning about the emerging practical applications of femtosecond optics, terahertz biomedicine and quantum information technologies.

  13. Photon propagators at finite temperature

    International Nuclear Information System (INIS)

    Yee, J.H.

    1982-07-01

    We have used the real time formalism to compute the one-loop finite temperature corrections to the photon self energies in spinor and scalar QED. We show that, for a real photon, only the transverse components develop the temperature-dependent masses, while, for an external static electromagnetic field applied to the finite temperature system, only the static electric field is screened by thermal fluctuations. After showing how to compute systematically the imaginary parts of the finite temperature Green functions, we have attempted to give a microscopic interpretation of the imaginary parts of the self energies. (author)

  14. Polymers for electronic & photonic application

    CERN Document Server

    Wong, C P

    2013-01-01

    The most recent advances in the use of polymeric materials by the electronic industry can be found in Polymers for Electronic and Photonic Applications. This bookprovides in-depth coverage of photoresis for micro-lithography, microelectronic encapsulants and packaging, insulators, dielectrics for multichip packaging,electronic and photonic applications of polymeric materials, among many other topics. Intended for engineers and scientists who design, process, and manufacturemicroelectronic components, this book will also prove useful for hybrid and systems packaging managers who want to be info

  15. Photonic wires and trumpets for ultrabright single photon sources

    DEFF Research Database (Denmark)

    Gérard, Jean-Michel; Claudon, Julien; Bleuse, Joël

    2013-01-01

    as to tailor their radiation diagram in the far-field. We highlight the novel “photonic trumpet” geometry, which provides a clean Gaussian beam, and is much less sensitive to fabrication imperfections than the more common needle-like taper geometry. S4Ps based on a single QD in a PW with integrated bottom...

  16. Fast pulse discriminator for photon counting at high photon densities

    International Nuclear Information System (INIS)

    Benoit, R.; Pedrini, A.

    1977-03-01

    A fast tunnel diode discriminator for photon counting up to 200MHz count frequency is described. The tunnel diode is operated on its apparent I.V. characteristics displayed when the diode is driven into its oscillating region. The pulse shaper-discriminator is completely D.C. coupled in order to avoid base-line shift at high pulse rates

  17. REVIEW: Optics of globular photonic crystals

    Science.gov (United States)

    Gorelik, V. S.

    2007-05-01

    The results of experimental and theoretical studies of the optical properties of globular photonic crystals - new physical objects having a crystal structure with the lattice period exceeding considerably the atomic size, are presented. As globular photonic crystals, artificial opal matrices consisting of close-packed silica globules of diameter ~200 nm were used. The reflection spectra of these objects characterising the parameters of photonic bands existing in these crystals in the visible spectral region are presented. The idealised models of the energy band structure of photonic crystals investigated in the review give analytic dispersion dependences for the group velocity and the effective photon mass in a globular photonic crystal. The characteristics of secondary emission excited in globular photonic crystals by monochromatic and broadband radiation are presented. The results of investigations of single-photon-excited delayed scattering of light observed in globular photonic crystals exposed to cw UV radiation and radiation from a repetitively pulsed copper vapour laser are presented. The possibilities of using globular photonic crystals as active media for lasing in different spectral regions are considered. It is proposed to use globular photonic crystals as sensitive sensors in optoelectronic devices for molecular analysis of organic and inorganic materials by the modern methods of laser spectroscopy. The results of experimental studies of spontaneous and stimulated globular scattering of light are discussed. The conditions for observing resonance and two-photon-excited delayed scattering of light are found. The possibility of accumulation and localisation of the laser radiation energy inside a globular photonic crystal is reported.

  18. Status reports on the development and application of acoustic emission analysis. Proceedings; Statusberichte zur Entwicklung und Anwendung der Schallemissionsanalyse. Beitraege

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2009-07-01

    This proceedings-CD comprises 20 papers presented at the 17. Kolloquium Schallemission (Acoustic Emission Colloquium) at Bad Schandau. The following subjects were discussed: 1. Acoustic emission analysis of tensile tests on standard test specimens of different wood materials; 2. Application of pattern recognition methods for damage analyses of fibre-reinforced plastics; 3. Acoustic emission analysis for measuring crack growth in finned armor steel under dynamic load; 4. Acoustic emission analysis with zonal sound location: Test objects, test results and evaluation of acoustic emission signals; 5. Acoustic emission analysis in overall fatigue testing of a wind rotor blade; 6. Laboratory methods for assessing the sensitivity of acoustic emission sensors; 7. Acoustic emission analysis in burst tests of cast aluminium casings; 8. Visualization of acoustic emission localizations; 9. Threshold-independent and complete recording of characteristics and wave forms of transient and continuous acoustic emission; 10. Characterization of wide-band acoustic emission sensors; 11. Handling of large data volumes in acoustic emission analysis, a contribution to the development of algorithms; 12. Acoustic emission analysis and ultrasonic analysis for the characterization of crack networks in saline rock. One of the papers is available as a separate record in this database. [German] Diese Tagungs-CD enthaelt 20 Vortraege, die auf dem 17. Kolloquium Schallemission in Bad Schandau gehalten wurden. Die Themen waren: 1. Schallemissionsanalyse von Zugversuchen an Standardpruefkoerpern aus unterschiedlichen Holzwerkstoffen; 2. Anwendung von Mustererkennungsverfahren zur Schadensanalyse in faserverstaerkten Kunststoffen; 3. Anwendung der Schallemissionsanalyse zur Ermittlung des Risswachstums bei schwingender Beanspruchung von geripptem Bewehrungsstahl; 4. Schallemissionspruefung mit zonaler Ortung Pruefobjekte, Pruefergebnisse und Nachbewertung von Schallemissionssignalen; 5

  19. Geometrical scaling of jet fragmentation photons

    Energy Technology Data Exchange (ETDEWEB)

    Hattori, Koichi, E-mail: koichi.hattori@riken.jp [RIKEN BNL Research Center, Brookhaven National Laboratory, Upton NY 11973 (United States); Theoretical Research Division, Nishina Center, RIKEN, Wako, Saitama 351-0198 (Japan); McLerran, Larry, E-mail: mclerran@bnl.gov [RIKEN BNL Research Center, Brookhaven National Laboratory, Upton NY 11973 (United States); Physics Dept., Bdg. 510A, Brookhaven National Laboratory, Upton, NY-11973 (United States); Physics Dept., China Central Normal University, Wuhan (China); Schenke, Björn, E-mail: bschenke@bnl.gov [Physics Dept., Bdg. 510A, Brookhaven National Laboratory, Upton, NY-11973 (United States)

    2016-12-15

    We discuss jet fragmentation photons in ultrarelativistic heavy-ion collisions. We argue that, if the jet distribution satisfies geometrical scaling and an anisotropic spectrum, these properties are transferred to photons during the jet fragmentation.

  20. Photon collisions as a glueball source

    International Nuclear Information System (INIS)

    Liu, H.C.

    1984-01-01

    Photon-photon and photon-nucleon collisions are suggested as a glueball source at small x in the collision center-of-mass frame. The glueball-production cross section is estimated through the two-gluon-fusion mechanism in perturbative quantum chromodynamics. The pointlike component of the photon structure function has a distinctive feature in that it consists almost purely of gluons at small x, which turns out to be very effective in producing glueballs. A much larger signal-to-noise ratio is expected in the glueball search in high-energy photon-photon and photon-nucleon collisions compared with hadron-hadron collisions. It is argued that the background due to soft collisions of the photons can be effectively reduced

  1. Photon Differential Splatting for Rendering Caustics

    DEFF Research Database (Denmark)

    Frisvad, Jeppe Revall; Schjøth, Lars; Erleben, Kenny

    2014-01-01

    We present a photon splatting technique which reduces noise and blur in the rendering of caustics. Blurring of illumination edges is an inherent problem in photon splatting, as each photon is unaware of its neighbours when being splatted. This means that the splat size is usually based...... on heuristics rather than knowledge of the local flux density. We use photon differentials to determine the size and shape of the splats such that we achieve adaptive anisotropic flux density estimation in photon splatting. As compared to previous work that uses photon differentials, we present the first method...... where no photons or beams or differentials need to be stored in a map. We also present improvements in the theory of photon differentials, which give more accurate results and a faster implementation. Our technique has good potential for GPU acceleration, and we limit the number of parameters requiring...

  2. Micro and nano lasers for digital photonics

    NARCIS (Netherlands)

    Hill, M.T.; Oei, Y.S.; Zhu, Y.C.; Smit, M.K.

    2007-01-01

    The small size, low-power and high-speed of nano-lasers make them an attractive nonlinear element for digital photonics. Further miniaturization of lasers below the diffraction limit is required before digital photonics can compete with electronics.

  3. Photonic analogies of gravitational attractors

    KAUST Repository

    San-Romá n-Alerigi, Damiá n P.; Alsunaidi, Mohammad A.; Ng, Tien Khee; Ooi, Boon S.; Ben Slimane, Ahmed; Zhang, Yaping

    2013-01-01

    In our work we demonstrate a Gaussian-like refractive index mapping to realize light trapping. Our study shows that this centro-symmetrical photonic structure is able to mime the light geodesics described by celestial mechanics. Possible applications are discussed. © 2013 IEEE.

  4. Applications of Graphene to Photonics

    Science.gov (United States)

    2014-07-01

    Engineering 52 (2013). [32] W. S. Koh , C. H. Gan, W. K. Phua, Y. A. Akimov, and P. Bai, “The potential of graphene as an ITO replacement in organic solar...1996). [70] S. Kivist, T. Hakulinen, M. Guina, and O. G. Okhotnikov, “Tunable raman soliton source using mode- locked tm-ho fiber laser,” IEEE Photonics

  5. Hadron induced leptons and photons

    International Nuclear Information System (INIS)

    Cronin, J.W.

    1977-01-01

    A review of direct production of leptons and photons in hadron-hadron collisions is presented. Production of lepton pairs with large mass is well accounted for by the Drell-Yan process. The origin of direct single leptons is principally due to the production of lepton pairs. A dominant source of lepton pairs is at low effective mass, m [de

  6. Photonic-crystal waveguide biosensor

    DEFF Research Database (Denmark)

    Skivesen, Nina; Têtu, Amélie; Kristensen, Martin

    2007-01-01

    A photonic-crystal waveguide sensor is presented for biosensing. The sensor is applied for refractive index measurements and detection of protein-concentrations. Concentrations around 10 μg/ml (0.15μMolar) are measured with excellent signal to noise ratio, and a broad, dynamic refractive index se...

  7. Photonic Crystals on the Wing

    Science.gov (United States)

    2011-11-01

    studying animal photonics; notably for the study of the optical properties of 3D structures [38]. Fig. 3. The Diamond Weevil, Entimus imperialis...Groningen/Exeter 3 August 2011 D.G. Stavenga Computational Physics Zernike Institute for Advanced Materials University of Groningen The

  8. Quartz substrate infrared photonic crystal

    Science.gov (United States)

    Ghadiri, Khosrow; Rejeb, Jalel; Vitchev, Vladimir N.

    2003-01-01

    This paper presents the fabrication of a planar photonic crystal (p2c) made of a square array of dielectric rods embedded in air, operating in the infrared spectrum. A quartz substrate is employed instead of the commonly used silicon or column III-V substrate. Our square structure has a normalized cylinder radius-to-pitch ratio of r/a = 0.248 and dielectric material contrast ɛr of 4.5. We choose a Z-cut synthetic quartz for its cut (geometry), and etching properties. Then a particular Z-axis etching process is employed in order to ensure the sharp-edged verticality of the rods and fast etching speed. We also present the computer simulations that allowed the establishment of the photonic band gaps (PBG) of our photonic crystal, as well as the actual measurements. An experimental measurement have been carried out and compared with different simulations. It was found that experimental results are in good agreement with different simulation results. Finally, a frequency selective device for optical communication based on the introduction of impurity sites in the photonic crystal is presented. With our proposed structure Optical System on a Chip (OsoC) with micro-cavity based active devices such as lasers, diodes, modulators, couplers, frequency selective emitters, add-drop filters, detectors, mux/demuxes and polarizers connected by passive waveguide links can be realized.

  9. Spin-photon entangling diode

    DEFF Research Database (Denmark)

    Flindt, Christian; Sørensen, A. S.; Lukin, M. D.

    2007-01-01

    We propose a semiconductor device that can electrically generate entangled electron spin-photon states, providing a building block for entanglement of distant spins. The device consists of a p-i-n diode structure that incorporates a coupled double quantum dot. We show that electronic control of t...

  10. Distinguishing Isolated Photons from Jets

    CERN Document Server

    Pieri, Marco; Branson, James G

    2006-01-01

    We have developed isolation and shower-shape variables that are optimized for reducing the jet background for a high transverse-energy photon signal. To help understand the relative importance of each variable, we have computed the background rejection power as a function of signal efficiency for these variables as well as for some simple combinations of variables. We find that a combination of tracker plus ECAL information can give very significant background rejection power. By adding information from the HCAL, the rejection power can be improved. In addition we find that a very significant reduction in background can be achieved by adding photon shower shape information from the ECAL to the Neural Net inputs. About 1 in 200 jets contains a high E_T electromagnetic shower that is reconstructed by the CMS software and is therefore a potential background for photon detection. An additional jet rejection factor of 100 with 80% photon efficiency (or 400 with 50% efficiency) can be achieved by using the isolatio...

  11. Luneburg lens in silicon photonics.

    Science.gov (United States)

    Di Falco, Andrea; Kehr, Susanne C; Leonhardt, Ulf

    2011-03-14

    The Luneburg lens is an aberration-free lens that focuses light from all directions equally well. We fabricated and tested a Luneburg lens in silicon photonics. Such fully-integrated lenses may become the building blocks of compact Fourier optics on chips. Furthermore, our fabrication technique is sufficiently versatile for making perfect imaging devices on silicon platforms.

  12. Single photon searches at PEP

    Energy Technology Data Exchange (ETDEWEB)

    Hollebeek, R.

    1985-12-01

    The MAC and ASP searches for events with a single photon and no other observed particles are reviewed. New results on the number of neutrino generations and limits on selection, photino, squark and gluino masses from the ASP experiment are presented.

  13. Single photon searches at PEP

    International Nuclear Information System (INIS)

    Hollebeek, R.

    1985-12-01

    The MAC and ASP searches for events with a single photon and no other observed particles are reviewed. New results on the number of neutrino generations and limits on selection, photino, squark and gluino masses from the ASP experiment are presented

  14. Sprache als Schlüssel zur Welt: Bibliotheken und Sprach-Kitas in guter Partnerschaft

    Directory of Open Access Journals (Sweden)

    Susanne Brandt

    2017-12-01

    Full Text Available Von 2016 bis voraussichtlich 2020 wird durch das Bundesministerium für Familie, Senioren, Frauen und Jugend das Bundesprogramm „Sprach-Kitas. Weil Sprache der Schlüssel zur Welt ist“ gefördert. Es richtet sich an Kindertageseinrichtungen, die von einem überdurchschnittlich hohen Anteil von Kindern mit besonderem Bedarf an sprachlicher Bildung und Förderung besucht werden. Dabei stehen besonders die folgenden drei Zielbereiche im Fokus: alltagsintegrierte sprachliche Bildung, inklusive Bildung und Zusammenarbeit mit den Familien. An den Standorten dieser mehr als 3000 Sprach-Kitas in Deutschland gibt es nahezu überall öffentliche Bibliotheken, die als nachbarschaftliche Partnerinnen den Sprach-Kitas bei der Sprachförderung mit vielfältigen Medien und Kooperationsangeboten zur Seite stehen. Auch als Schnittstelle zwischen Kita und Familie können die Büchereien wichtige Aufgaben im Rahmen des Programms übernehmen. Die Büchereizentrale Schleswig-Holstein hat daher mit Fördermitteln des Landes und in guter Abstimmung mit den Sprachkoordinatorinnen der Kitas das Projekt „Mit Worten wachsen“ entwickelt. Der Beitrag beschreibt, welche Chancen und Herausforderungen sich durch eine solche Zusammenarbeit mit Sprach-Kitas für Bibliotheken ergeben und wie sich daraus eine lebendige interdisziplinäre Partnerschaft im Sinne der genannten Zielbereiche entwickeln lässt. Since 2016, the Federal Ministry for Family Affairs, Senior Citizens, Women and Youth has sponsored the programme “Language day-care centres. Because language is the key to the world” (Sprach-Kitas. Weil Sprache der Schlüssel zur Welt ist; this is expected to last until 2020. The programme addresses day-care facilities which are attended by an above-average number of children with special needs in their language development. The following three aims are at the centre of the programme: language education which is integrated in everyday life; education based on

  15. Photons and diphotons from the Tevatron

    International Nuclear Information System (INIS)

    Blair, R.

    1997-08-01

    Photon measurements from the CDF and D0 collaboration are described. The subjects touched on are loosely organized around the fact that they all have some bearing on the structure functions and pQCD. The methodology of collider measurements is briefly reviewed, and the results for single photons, photons plus jets, photons plus charm and diphotons are discussed. Finally there is a very brief indication of what is expected from the Tevatron based experiments in the future

  16. Silicon Photonics Cloud (SiCloud)

    DEFF Research Database (Denmark)

    DeVore, P. T. S.; Jiang, Y.; Lynch, M.

    2015-01-01

    Silicon Photonics Cloud (SiCloud.org) is the first silicon photonics interactive web tool. Here we report new features of this tool including mode propagation parameters and mode distribution galleries for user specified waveguide dimensions and wavelengths.......Silicon Photonics Cloud (SiCloud.org) is the first silicon photonics interactive web tool. Here we report new features of this tool including mode propagation parameters and mode distribution galleries for user specified waveguide dimensions and wavelengths....

  17. Resonant interaction of photons with gravitational waves

    International Nuclear Information System (INIS)

    Mendonca, J.T.; Drury, L. O'C.

    2002-01-01

    The interaction of photons with a low-amplitude gravitational wave propagating in a flat space-time is studied by using an exact model of photon dynamics. The existence of nearly resonant interactions between the photons and the gravitational waves, which can take place over large distances, can lead to a strong photon acceleration. Such a resonant mechanism can eventually be useful to build consistent new models of gamma-ray emitters

  18. Time correlation in two-photon decay

    International Nuclear Information System (INIS)

    Hrasko, P.

    1979-11-01

    The relative time distribution of the photons emitted in a second order non-cascade process b→a+2γ is investigated under the assumption that only those photon pairs are detected which were emitted a sufficiently long time after the preparation of the decaying state. An anticorrelation between the photons is found and attributed to the propagation of one of the photons backward in time. (author)

  19. Biomedical photonics handbook therapeutics and advanced biophotonics

    CERN Document Server

    Vo-Dinh, Tuan

    2014-01-01

    Shaped by Quantum Theory, Technology, and the Genomics RevolutionThe integration of photonics, electronics, biomaterials, and nanotechnology holds great promise for the future of medicine. This topic has recently experienced an explosive growth due to the noninvasive or minimally invasive nature and the cost-effectiveness of photonic modalities in medical diagnostics and therapy. The second edition of the Biomedical Photonics Handbook presents recent fundamental developments as well as important applications of biomedical photonics of interest to scientists, engineers, manufacturers, teachers,

  20. Photon structure as seen at HERA

    International Nuclear Information System (INIS)

    Butterworth, J.M.

    1995-03-01

    At HERA, the electron-proton collider at DESY, Hamburg, the large flux of almost on-shell photons accompanying the lepton beam is being used to shed new light on the structure of the photon. Recent results are reviewed and discussed, with emphasis on those aspects of the photon's nature which should be understandable using perturbative QCD. (orig.)

  1. Moore’s law in photonics

    NARCIS (Netherlands)

    Smit, M.K.; Tol, van der J.J.G.M.; Hill, M.T.

    2012-01-01

    A review of the complexity development of InP-based Photonic ICs is given. Similarities and differences between photonic and microelectronic integration technology are discussed and a vision of the development of photonic integration in the coming decade is given.

  2. Photon structure as seen at HERA

    International Nuclear Information System (INIS)

    Butterworth, J.M.

    1995-01-01

    At HERA, the lepton-proton collider at DESY, Hamburg, the large flux of almost on-shell photons accompanying the lepton beam is being used to shed new light on the structure of the photon. Recent results are reviewed and discussed, with emphasis on those aspects of the photon's nature which should be understandable using perturbative QCD. (author)

  3. Photonic hybrid assembly through flexible waveguides

    NARCIS (Netherlands)

    Wörhoff, K.; Prak, A.; Postma, F.; Leinse, A.; Wu, K.; Peters, T. J.; Tichem, M.; Amaning-Appiah, B.; Renukappa, V.; Vollrath, G.; Balcells-Ventura, J.; Uhlig, P.; Seyfried, M.; Rose, D.; Santos, R.; Leijtens, X.J.M.; Flintham, B.; Wale, M.; Robbins, D.

    2016-01-01

    Fully automated, high precision, cost-effective assembly technology for photonic packages remains one of the main challenges in photonic component manufacturing. Next to the cost aspect the most demanding assembly task for multiport photonic integrated circuits (PICs) is the high-precision (±0.1 μm)

  4. Photonic hybrid assembly through flexible waveguides

    NARCIS (Netherlands)

    Wörhoff, Kerstin; Prak, Albert; postma, F; Leinse, A; Wu, K.; Peters, T.J.; Tichem, M.; Amaning-Appiah, B.; Renukappa, V.; Vollrath, G.; Balcells-Ventura, J.; Uhlig, P.; Seyfried, M.; Rose, D.; Santos, Raquel; Leijtens, XJM; Flintham, B.; Wale, M.; Robbins, D.; Vivien, Laurent; Pavesi, Lorenzo; Pelli, Stefano

    2016-01-01

    Fully automated, high precision, cost-effective assembly technology for photonic packages remains one of the main challenges in photonic component manufacturing. Next to the cost aspect the most demanding assembly task for multiport photonic integrated circuits (PICs) is the high-precision (±0.1

  5. ePIXfab - The silicon photonics platform

    NARCIS (Netherlands)

    Khanna, A.; Drissi, Y.; Dumon, P.; Baets, R.; Absil, P.; Pozo Torres, J.M.; Lo Cascio, D.M.R.; Fournier, M.; Fedeli, J.M.; Fulbert, L.; Zimmermann, L.; Tillack, B.; Aalto, T.; O'Brien, P.; Deptuck, D.; Xu, J.; Gale, D.

    2013-01-01

    ePIXfab-The European Silicon Photonics Support Center continues to provide state-of-the-art silicon photonics solutions to academia and industry for prototyping and research. ePIXfab is a consortium of EU research centers providing diverse expertise in the silicon photonics food chain, from training

  6. Aussagen zur deutschen Sprache in den zwischen 2003 und 2013 erschienenen Werken der Chamisso-Preistragenden

    Directory of Open Access Journals (Sweden)

    Johannes Gröbl

    2017-04-01

    Full Text Available Da sich aus Aussagen von Chamisso-Literatur-Verfassenden über die deutsche Sprache interessante Schlüsse ziehen lassen, wird im Folgenden eine Sammlung von entsprechenden Zitaten aus Werken der Chamisso-Preistragenden aus den Jahren 2003 bis 2013 nach linguistischen Themen sortiert präsentiert. Die beispielhafte Dekade ist nicht völlig willkürlich gewählt, denn sie zeigt sich als ein Zeitraum, in dem viele der bisherigen Chamisso-Preistragenden tatsächlich Werke veröffentlichten. Sie bietet sich daher dafür an, exemplarisch zu zeigen, welche Aussagen über die deutsche Sprache aus Chamisso-Literatur gewonnen werden können. Der folgende Artikel zeigt, dass schon ein überschaubarer zeitlicher Ausschnitt aus der Chamisso-Literatur eine große Menge an Aussagen zur deutschen Sprache liefert. Ein größeres oder sogar vollständiges Bild wäre daher höchstens in einer umfangreicheren Arbeit zu zeichnen möglich. Zunächst soll nun dargestellt werden, weshalb es sich lohnen könnte, sich mit Aussagen von Chamisso-Literatur-Verfassenden bzw. -Preistragenden zur deutschen Sprache zu beschäftigen (Kap. 1, bevor die Zitate geordnet nach linguistischen (Kap. 2 und anthropologischen (Kap. 3 Beschreibungskategorien dargestellt werden und schließlich nach einer kurzen Zusammenfassung (Kap. 4.1 ein Ausblick gewagt wird (Kap. 4.2. As it is possible to draw interesting conclusions from remarks of Chamisso-authors about the German language, the following article presents a collection of corresponding citations from works published between 2003 and 2013 of authors, who have been awarded with the Chamisso-Award. Citations are sorted by linguistic and anthropological topics. The chosen decade can be considered representative, because it shows a time period, when many of the Chamisso-Awardees did actually publish their works. It is therefore very suitable to show, which kinds of remarks about the German language can be found in Chamisso-literature. The

  7. Final-photon polarization in the scattering of photons by high-energy electrons

    International Nuclear Information System (INIS)

    Choi, J.; Choi, S.Y.; Ie, S.H.; Song, H.S.; Good, R.H. Jr.

    1987-01-01

    A general method for calculating the polarization of the outgoing photon beam in any reaction is presented. As an example the method is applied to the high-energy photon beam produced in Compton scattering of a laser beam by a high-energy electron beam. The Stokes parameters of the outgoing photon beam, relative to a unit vector normal to the photon momentum and including their dependence on the polarization of incident photon and electron beams, are obtained explicitly. It is expected that this method will be useful, both in photon production reactions and in the subsequent high-energy photon reactions

  8. Logfile-Analysen zur Evaluation der didaktischen Einbettung von CSCL-Systemen - am Beispiel der CommSy-Nutzung in offenen Seminaren

    Directory of Open Access Journals (Sweden)

    Martin Klein

    2005-02-01

    Full Text Available In unserem Beitrag evaluieren wir die didaktische Einbettung einer CSCL-Anwendung anhand von Logfile-Analysen. Dazu betrachten wir exemplarisch die Nutzung des webbasierten Systems CommSy in einer projektorientierten Lehrveranstaltung, die wir als offenes Seminar charakterisieren. Wir erzielen zwei Ergebnisse: (1 Wir geben Hinweise zur Gestaltung des Nutzungskontexts eines CSCL-Systems sowie zur Unterstützung seiner anfänglichen und kontinuierlichen Nutzung. (2 Wir beschreiben die Analyse von Nutzungsanlässen und -mustern sowie von NutzerInnentypen anhand von Logfiles. Dabei können Logfile-Analysen zur Validierung weiterer Evaluationsergebnisse dienen, sind selbst jedoch nur in Kombination mit zusätzlichen Informationen zum Nutzungskontext interpretierbar.

  9. Hints on cost- and energy saving during lime-sand brick production; Hinweise zur Kosten- und Energieeinsparung bei der Kalksandstein-Produktion

    Energy Technology Data Exchange (ETDEWEB)

    Eden, W.

    2001-05-01

    The publication contains hints for reduction of energy consumption and cost in lime-sand brick production. The information was compiled by Bundesverband Kalksandsteinindustrie e.V. and was derived from technical discussions of the master seminars on production technology of the years 1995 - 2000, consultations form member organizations, or from other sources. [German] Diese Arbeit ist eine Zusammenstellung von Hinweisen zur Reduzierung des Energieverbrauchs und der Kostensenkung bei der KS-Produktion und soll eine Hilfestellung bei entsprechenden Rationalisierungsmassnahmen in den Mitgliedsunternehmen sein. Die hier aufgefuehrten Hinweise und Anregungen entstammen den Fachdiskussionen der Meisterseminare zur Produktionstechnik aus den Jahren 1995 bis 2000, Beratungsgespraechen fuer Mitgliedsunternehmen oder wurden dem Bundesverband Kalksandsteinindustrie eV freundlicherweise fuer die Gemeinschaftsarbeit zur Verfuegung gestellt. (orig.)

  10. Studien zur Messung von Rekonstruktionseffizienz und Untergrund der $\\tau$-Lepton-Identifikation im Zerfall $Z\\to \\tau \\tau$ beim ATLAS-Experiment aus Daten

    CERN Document Server

    Johnert, Sebastian

    2008-01-01

    In dieser Diplomarbeit werden zwei Methoden vorgestellt, mit denen τ -Leptonen in den zuk ̈nf- u tigen Daten des ATLAS-Experiments untersucht werden sollen. Den ersten Teil bildet die Be- stimmung von Missidentifikationsraten von Jets aus QCD-2-Jet-Ereignissen als τ -Leptonen. Der zweite Teil ist die Entwicklung einer Methode zur Bestimmung der τ -Rekonstruktions- und -Identifikationseffizienz relativ zur μ-Effizienz. In diesem Zusammenhang werden invariante Massen aus Z → ll-Ereignissen bestimmt, die Massen aus Z → τ τ -Ereignissen mit denen aus Z → ee und Z → μμ verglichen, τ -Effizienzen gemittelt uber alle Bereiche und in verschiedenen ̈ o η-Bereichen berechnet sowie eine M ̈glichkeit zur Bestimmung von τ -Effizienzen in unterschied- lichen Transversalimpulsbereichen vorgestellt. Des Weiteren wird eine verbesserte Absch ̈tzung a des QCD-Untergrunds vorgenommen und das Verhalten der τ -Effizienz unter Ber ̈cksichtigung u des Triggers untersucht.

  11. Balancing and dynamic behaviour of a biofilter plant for complete cleaning of municipal sewage; Bilanzierung und dynamisches Verhalten einer Biofilteranlage zur Vollreinigung von kommunalem Abwasser

    Energy Technology Data Exchange (ETDEWEB)

    Dickgreber, M.; Luebbecke, S. [Preussag Wassertechnik GmbH, Bremen (Germany)

    1999-07-01

    Where municipal sewage treatment plants need to be extended or enlarged, biofilter systems represent an economical alternative. They can be used both for supplementary residual elimination purposes and to treat complete sewage streams. For a biofilter system for complete cleaning of sewage employing the DENIPOR trademark -NCS process which has been in operation since 1996 (2*500 population value), studies in process dynamics are carried out and a complete balance is set up. (orig.) [German] Biofilter stellen bei notwendigen Erweiterungen und Ausbaumassnahmen von kommunalen Klaeranlagen eine wirtschaftliche Alternative dar. Sie koennen fuer weitergehende Restreinigungsaufgaben und zur Vollstrombehandlung eingesetzt werden. An einer seit 1996 in Betrieb befindlichen Biofilteranlage zur Vollreinigung von kommunalem Abwasser nach dem DENIPOR {sup trademark} -NCS Verfahren (2*500EW) werden Untersuchungen zur Prozessdynamik sowie eine vollstaendige Bilanzierung durchgefuehrt. (orig.)

  12. The method of the photoelectron spectroscopy for the observation of ultrafst processes in metals; Die Methode der Photoelektronenspektroskopie zur Beobachtung ultraschneller Prozesse in Metallen

    Energy Technology Data Exchange (ETDEWEB)

    Heinz, Oliver

    2007-12-15

    An essential thematic main topic of this experimental-physical thesis is the observation of the thermalization of hot electrons of a metal film, which were excited and heated by an ultrashort laser pulse. Applied for this was a modification of the method of the photoelectron spectroscopy, at which it is by an optical-pump examination technique possible, to study the dynamics of the electron energy distribution in the metal with high time resolution. The laser pulses required for the surpassing of the metal escape work in the ultraviolet spectral range are by that produced, that pulses of a Ti:sapphire laser system in the infrared spectral region and a pulse duration of 40 femtoseconds are frequency-multiplied. For the success of this measurement method with high time resolution high requirements both on the quality of the exciting laser pulses and the ultrahigh-vacuum apparature of the photoelectron spectrometer are indispensable. The essential details of these special requirements are extensively discussed in this thesis. The excitation of the metal sample by intense and ultrashort laser pulses of different wavelength led after evaluation of the photoemission spectra and after analysis of the structural character of the metal surface to an extension of already existing knowledge concerning the photoemission at simultaneous absorption of two or several photons. [German] Ein wesentlicher thematischer Schwerpunkt dieser experimentalphysikalischen Arbeit ist die Beobachtung der Thermalisierung heisser Elektronen eines Metallfilms, welche mit einem ultrakurzen Laserimpuls angeregt und aufgeheizt wurden. Verwendet wurde dazu eine Abwandlung der Methode der Photoelektronenspektroskopie, bei der es durch eine optische Pump-Abfrage-Technik moeglich ist, die Dynamik der Elektronenenergieverteilung im Metall mit hoher Zeitaufloesung zu untersuchen. Die zur Ueberwindung der metallischen Austrittsarbeit erforderlichen Laserimpulse im ultravioletten Spektralbereich werden

  13. Opal-based photonic crystal with double photonic bandgap structure

    Science.gov (United States)

    Romanov, S. G.; Yates, H. M.; Pemble, M. E.; DeLa Rue, R. M.

    2000-09-01

    The interior surfaces of one part of a piece of artificial opal have been coated with GaP so that the remaining part of the opal crystal remains empty, thus forming a photonic heterostructure. Two Bragg resonances have been observed in the optical transmission and reflectance spectra. These two resonances were found to behave differently with changes in the polarization of the incident light and the angle of propagation of the light with respect to the (111) planes of opal. Depolarization of the light was observed to occur most effectively at frequencies within the stop-bands, apparently due to the re-coupling of the propagating electromagnetic wave to a different system of eigenmodes when it crosses the interface separating two parts of the double photonic crystal.

  14. Photon management assisted by surface waves on photonic crystals

    CERN Document Server

    Angelini, Angelo

    2017-01-01

    This book illustrates original pathways to manipulate light at the nanoscale by means of surface electromagnetic waves (here, Bloch surface waves, BSWs) on planar dielectric multilayers, also known as one-dimensional photonic crystals. This approach is particularly valuable as it represents an effective alternative to the widely exploited surface plasmon paradigm. After a brief overview on the fundamentals of BSWs, several significant applications of BSW-sustaining structures are described. Particular consideration is given to the propagation, guiding, and diffraction of BSW-coupled radiation. Further, the interaction of organic emitters with BSWs on planar and corrugated multilayers is investigated, including fluorescence beaming in free space. To provide greater insight into sensing applications, an illustrative example of fluorescent microarray-based detection is presented. The book is intended for scientists and researchers working on photon management opportunities in fields such as biosensing, optical c...

  15. Chargino production and decay in photon-photon collisions

    International Nuclear Information System (INIS)

    Mayer, T.; Bloechinger, C.; Franke, F.; Fraas, H.

    2003-01-01

    We discuss the pair production of charginos in collisions of polarized photons, γγ→χ i + χ i - (i=1,2), and the subsequent leptonic decay of the lighter chargino χ 1 + →χ 1 0 e + ν e including the complete spin correlations. Analytical formulae are given for the polarization and the spin-spin correlations of the charginos. Since the production is a pure QED process the decay dynamics can be studied separately. For high energy photons from Compton backscattering of polarized laser pulses off polarized electron beams numerical results are presented for the cross section, the angular distribution and the forward-backward asymmetry of the decay positron. Finally we study the dependence on the gaugino mass parameter M 1 and on the sneutrino mass for a gaugino-like MSSM scenario. (orig.)

  16. Nuclear photon science with inverse compton photon beam

    International Nuclear Information System (INIS)

    Fujiwara, Mamoru

    2007-01-01

    Recent developments of the synchrotron radiation facilities and intense lasers are now guiding us to a new research frontier with probes of a high energy GeV photon beam and an intense and short pulse MeV γ-ray beam. New directions of the science developments with photo-nuclear reactions are discussed. The inverse Compton γ-ray has two good advantages for searching for a microscopic quantum world; they are 1) good emittance and 2) high linear and circular polarizations. With these advantages, photon beams in the energy range from MeV to GeV are used for studying hadron structure, nuclear structure, astrophysics, materials science, as well as for applying medical science. (author)

  17. Photonics4All - Conduct photonics for investment in France and Slovakia

    OpenAIRE

    Gerente, Fiona; Chorvat, Dusan

    2017-01-01

    This project deliverable describes the organisation of different Photonics for Investment Events. “Photonics for investments” focuses on the support and investment in innovative ideas and photonics applications. The objective of this project task is to provide the opportunity for Photonics SMEs to present their products or services during pitch presentations to new customers and investors. The Photonics for Investment events have three main objectives. The first objective is to connect en...

  18. High-Energy QCD Asymptotics of Photon--Photon Collisions

    Energy Technology Data Exchange (ETDEWEB)

    Brodsky, Stanley J.

    2002-07-26

    The high-energy behavior of the total cross section for highly virtual photons, as predicted by the BFKL equation at next-to-leading order (NLO) in QCD, is discussed. The NLO BFKL predictions, improved by the BLM optimal scale setting, are in good agreement with recent OPAL and L3 data at CERN LEP2. NLO BFKL predictions for future linear colliders are presented.

  19. High-Energy QCD Asymptotics of Photon-Photon Collisions

    CERN Document Server

    Brodsky, S J; Kim, V T; Lipatov, L N; Pivovarov, G B

    2002-01-01

    The high-energy behaviour of the total cross section for highly virtual photons, as predicted by the BFKL equation at next-to-leading order (NLO) in QCD, is discussed. The NLO BFKL predictions, improved by the BLM optimal scale setting, are in good agreement with recent OPAL and L3 data at CERN LEP2. NLO BFKL predictions for future linear colliders are presented.

  20. Pion pair production in photon-photon interactions

    International Nuclear Information System (INIS)

    Berger, C.; Deuter, A.; Genzel, H.; Lackas, W.; Pielorz, J.; Raupach, F.; Wagner, W.; Bussey, P.J.; Cartwright, S.L.; Dainton, J.B.; King, B.T.; Raine, C.; Scarr, J.M.; Skillikorn, I.O.; Smith, K.M.; Thomson, J.C.; Achterberg, O.; Blobel, V.; Burkart, D.; Diehlmann, K.; Feindt, M.; Kapitza, H.; Koppitz, B.; Krueger, M.; Poppe, M.; Spitzer, H.; Staa, R. van; Almeida, F.; Baecker, A.; Barreiro, F.; Brandt, S.; Derikum, K.; Grupen, C.; Meyer, H.J.; Mueller, H.; Neumann, B.; Rost, M.; Stupperich, K.; Zech, G.; Alexander, G.; Bella, G.; Gnat, Y.; Grunhaus, J.; Junge, H.; Kraski, K.; Maxeiner, C.; Maxeiner, H.; Meyer, H.; Schmidt, D.; Buerger, J.; Criegee, L.; Ferrarotto, F.; Franke, G.; Gaspero, M.; Gerke, C.; Knies, G.; Lewendel, B.; Meyer, J.; Michelsen, U.; Pape, K.H.; Stella, B.; Timm, U.; Winter, G.G.; Zachara, M.; Zimmermann, W.

    1984-08-01

    The process γγ -> π + π - has been measured with complete particle identification. Cross-sections are presented from near threshold up to the region of the f(1270). In the mass range 0.5-0.7 GeV, cross-sections are lower than the Born term predictions and show no evidence for an epsilon(600). The two-photon width of the f(1270) is found to be in agreement with previous results. (orig.)