Zobrazeno 1 - 10
of 10
pro vyhledávání: '"Barend Visser"'
Autor:
Barend Visser, Paulus Kruger
Publikováno v:
2017 European Radar Conference (EURAD).
A novel way to calculate the sensitivity and beam-former coefficients of a receiver consisting of coupled antennas and an optimum beamformer is presented. The low-noise amplifier (LNA) connected to each antenna is replaced with a load, which has an i
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::a2271e55a136aa59c283d208d2bf9b67
https://doi.org/10.23919/eurad.2017.8249188
https://doi.org/10.23919/eurad.2017.8249188
Publikováno v:
2017 47th European Microwave Conference (EuMC).
A simple, inexpensive, fully integrated low-noise amplifier and antenna for the Square Kilometer Array (SKA) Mid-Frequency Aperture Array (MFAA) is presented which achieves a receiver noise figure of about 0.4 dB over more than an octave bandwidth. A
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::d384af6ae674aa9291fe7ca51295d610
https://doi.org/10.23919/eumc.2017.8230798
https://doi.org/10.23919/eumc.2017.8230798
Autor:
Paulus Kruger, Barend Visser
Publikováno v:
Ignition Systems for Gasoline Engines ISBN: 9783319455037
Due to stringent emission and fuel consumption requirements, several innovative ignition systems have been proposed to address the shortcomings of current spark ignition systems. Two of the most promising candidates are high-energy spark ignition sys
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::5c60c5c54ee9bb3b6d32fb4292c24388
https://doi.org/10.1007/978-3-319-45504-4_16
https://doi.org/10.1007/978-3-319-45504-4_16
Publikováno v:
IEEE Transactions on Microwave Theory and Techniques. 59:414-424
The theoretical minimum noise measure of a multipath amplifier (an amplifier that has multiple parallel amplifiers) is achieved by using the optimum source impedance and optimum gain for each amplification path. This optimum source impedance and gain
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::6ae7b088c41ed3edcf1a1b86ac93553c
https://doi.org/10.1109/tmtt.2010.2095878
https://doi.org/10.1109/tmtt.2010.2095878
Publikováno v:
AIP Conference Proceedings.
Observations and theoretical studies have demonstrated that the pulsed spectra of all gamma-ray pulsars terminate at energies below a few hundred GeV. In most cases we expect this cutoff energy E_o to be around 10 GeV. Only with next generation groun
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::f1e291c6fe9d0595b135c7ad3203a7a5
https://doi.org/10.1063/1.1370835
https://doi.org/10.1063/1.1370835
Autor:
H. I. Nel, Barend Visser, B. C. Raubenheimer, G. van Urk, A. R. North, C. Brink, L. J. Haasbroek, P. J. Meintjes, O. C. de Jager
Publikováno v:
AIP Conference Proceedings.
We present the first results of TeV γ‐ray observations of PSR1706−44, indicating a sharp spectral break between ∼10 GeV and 1000 GeV. Our and other results confirm similar breaks from other γ‐ray pulsars such as Vela, PSR1509−58 and Gemin
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::c3f4be7133582fee02fd5b1e7792454f
https://doi.org/10.1063/1.44129
https://doi.org/10.1063/1.44129
Autor:
C. Brink, G. van Urk, H. I. Nel, O. C. de Jager, P. J. Meintjes, A. R. North, Barend Visser, B. C. Raubenheimer, David A. H. Buckley
Publikováno v:
Lecture Notes in Physics ISBN: 9783540547891
We present results of near simultaneous optical and TeV observations made on Sept. 14, 1990 of the novalike cataclysmic variable AE Aquarii. The optical was in a flaring state resulting in a bolometric luminosity which may have been high enough to gi
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::5a4d5a09c38527eb06cf9baa4b64e5ce
https://doi.org/10.1007/3-540-54789-4_69
https://doi.org/10.1007/3-540-54789-4_69
Autor:
B. C. Raubenheimer, D. O'Donoghue, P. J. Meintjes, A. R. North, O. C. de Jager, H. I. Nel, C. Brink, G. van Urk, Barend Visser
Publikováno v:
AIP Conference Proceedings.
Evidence is presented that Vela X‐1 emits steady pulsed emission at the X‐ray period. Another X‐ray binary, Cen X‐3, also show evidence for steady, pulsed emission at the expected X‐ray period, but this emission only occurs in the orbital p
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::2b9f7966db86e8dcea87bb5dbf62e4fb
https://doi.org/10.1063/1.40325
https://doi.org/10.1063/1.40325
Autor:
A. R. North, P. J. Meintjes, C. Brink, B. C. Raubenheimer, H. I. Nel, O. C. de Jager, G. van Urk, Barend Visser
Publikováno v:
The Astrophysical Journal. 401:325
During optical flares, strong coherent pulsed emission is detected in the frequency interval ∼29.9-30.0 mHz and at F 0 =30.23 mHz (rotation frequency). Evidence is presented of pulsed VHE emission at these frequencies in all our VHE data at the 99.
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::3108e904931b11b5f72fd2686adae001
https://doi.org/10.1086/172063
https://doi.org/10.1086/172063
Autor:
C. Brink, L. Scarsi, Volker Schoenfelder, D. J. van der Walt, R. Buccheri, B. C. Raubenheimer, O. C. de Jager, P. von Ballmoos, C. M. Carollo, H. I. Nel, M. Varendorf, Barend Visser, A. R. North, G. van Urk
Publikováno v:
The Astrophysical Journal. 364:L37
Les donnees du telescope Cerenov de Potchefstroom, du satellite COS B et du telescope Compton MPE sont analysees pour detecter la presence d'un signal de rayonnement gamma en direction du pulsar binaire a eclipse PSR 1957+20. Une emission Rγ possibl
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::edaa788a0dde552bac84c3cbe765ebb0
https://doi.org/10.1086/185869
https://doi.org/10.1086/185869