134,078 research outputs found
Large zenith angle observations of Mkn 421 with H.E.S.S
No full textMkn 421 was observed during 2004 with the fully operational High Energy Stereoscopic System (H.E.S.S.) in Namibia. The observations were carried out at zenith angles of 60°-67°, which result in an average energy threshold of 1.5 TeV and a collection area reaching 2 km² at 10 TeV. The light-curve of integrated fluxes above 2 TeV shows changes of the diurnal ux up to a factor of 4.3. For nights of high flux, intra-night variability is detected with a decay time of less than 1 hour. The time averaged energy spectrum is curved and is well described by a power-law with a photon index 2.1±0.1 and an exponential cutoff at 3.1 (+0.5 - 0.4)TeV and an average integral flux above 2 TeV of 3 Crab ux units. Significant variations of the spectral shape are detected with a spectral hardening as the ux increases. Contemporaneous multi-wavelength observations at lower energies (X-rays and gamma-rays above ± 300 GeV) indicate smaller relative variability amplitudes than seen above 2 TeV during the high flux state
Fine Horns for Sale by L. D. Bertillion, Mineola, Tex.
No full textPortrait of a man holding a mounted set of horns.Verso: [handwritten] Fine Horns for Sale by L D Bertillion Mineola Te
Microwave Horns and Feeds
No full textThe following topics are dealt with: reflector antennas; radiation from apertures; numerical analysis using cylindrical and spherical waves in horns; numerical analysis of small axisymmetric feeds; pure-mode horns; prime-focus waveguide feeds; multimode horns; corrugated horns; dielectric-loaded horns; lens-corrected horns; dielectric feeds; dipole feeds; microstrip and resonator type feeds; and array feed
3-d printing of high-performance feed horns from Ku-to V-bands
No full textIn this letter, the design and the three-dimensional (3-D) printing of high-performance feed horns operating within Ku- A nd V-bands are presented. A smooth-wall architecture has been preferred in order to ease the manufacturing and to enhance the 3-D printing quality. A suitable design procedure has been developed for the synthesis of dual-band smooth-wall feeds. Single-band and dual-band all-metal prototypes have been manufactured through the selective laser melting technology. A remarkable agreement between the predicted and measured performances has been achieved also for the higher frequency Q/V-band feed horn with measured return-loss higher than 33 dB, cross-polarization lower than-28 dB, and peak gain of 25 dBi
horn; horns
No full texthornNow - I'm tellin' a lie, I never saw the squid, but you know the - those suckers be on the horns, you know. (part of squid)(part of squid)YesDNE-cit J. D. A. WIDDOWSONUsed I and SupUsed I and Sup1Used
The New Unidentified TeV Source in Cygnus (TeV J2032+4130): HEGRA IACT-System Results
No full text© 2003 by Universal Academy Press, Inc.Gavin Rowell, Dieter Horns, for the HEGRA Collaboratio
Directivity of underwater horns
No full textThe literature on acoustical horns is surveyed. An experimental study of the directivity gain of underwater transducers with the attachment of horns is described. Factors influencing such directionality are established for exponential, tractrix and conical horns. The influence of steel and aluminum for construction materials, and the effects of polyurethane foam or air backings are determined. The directivity index is found to show sudden drops at discrete frequencies. It is shown that this behavior is related to transverse modes of propagation inside the horn through the probing of the mouth of the horn for acoustic pressure and phase variations. The effect on directivity of various cell arrangements in a conical horn are studied but with Inconclusive results.Mechanical Engineering, Department o
horn; horns
No full texthornThe landing was made of three skids goin' down to the edge of the riverbank, and there was...there was horns comin' down at the front o' the river, you know, an' now there was...there was... 'twas all axe-work ...YesDNE-cit J. D. A. WIDDOWSONUsed I and SupUsed I and Sup4Used
A New TeV Source in the Vicinity of Cygnus OB2
No full textGavin Rowell and Dieter Horns (for the HEGRA Collaboration)http://icrhp9.icrr.u-tokyo.ac.jp/abstract/Symp2002
draw in his horns
No full textdrawI soon made him draw in his horns. - made him 'take back-water', 'give in'.JH 1/74 JH 1/74Used I and SupNot usedWithdraw
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