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radio frequency emission

Fang-Hsing Wang, Kun-Neng Chen, Chao-Ming Hsu, Min-Chu Liu, Cheng-Fu Yang
In this study, Ga₂O₃-doped ZnO (GZO) thin films were deposited on glass and flexible polyimide (PI) substrates at room temperature (300 K), 373 K, and 473 K by the radio frequency (RF) magnetron sputtering method. After finding the deposition rate, all the GZO thin films with a nano-scale thickness of about 150 ± 10 nm were controlled by the deposition time. X-ray diffraction patterns indicated that the GZO thin films were not amorphous and all exhibited the (002) peak, and field emission scanning electron microscopy showed that only nano-scale particles were observed...
May 10, 2016: Nanomaterials
W J Wan, H Li, T Zhou, J C Cao
Homogeneous broadband and electrically pumped semiconductor radiation sources emitting in the terahertz regime are highly desirable for various applications, including spectroscopy, chemical sensing, and gas identification. In the frequency range between 1 and 5 THz, unipolar quantum cascade lasers employing electron inter-subband transitions in multiple-quantum-well structures are the most powerful semiconductor light sources. However, these devices are normally characterized by either a narrow emission spectrum due to the narrow gain bandwidth of the inter-subband optical transitions or an inhomogeneous broad terahertz spectrum from lasers with heterogeneous stacks of active regions...
March 8, 2017: Scientific Reports
Raimondas Buckus, Birute Strukčinskienė, Juozas Raistenskis, Rimantas Stukas, Aurelija Šidlauskienė, Rimantė Čerkauskienė, Dorina Nicolina Isopescu, Jan Stabryla, Igor Cretescu
During the last two decades, the number of macrocell mobile telephony base station antennas emitting radiofrequency (RF) electromagnetic radiation (EMR) in residential areas has increased significantly, and therefore much more attention is being paid to RF EMR and its effects on human health. Scientific field measurements of public exposure to RF EMR (specifically to radio frequency radiation) from macrocell mobile telephony base station antennas and RF electromagnetic field (EMF) intensity parameters in the environment are discussed in this article...
March 1, 2017: International Journal of Environmental Research and Public Health
S J Doyle, K G Xu
This paper presents the use of thermocouples and line broadening of argon 2p-1s emission lines for the measurement of gas temperature of an atmospheric argon microplasma jet. The measured temperatures are compared with rotational spectra fitting of OH (A-X) and N2 (C-B) emission. An rf microplasma jet with two electrical configurations and different temperature ranges was used. The calculated gas temperatures with thermocouples, argon lines, and OH ranged from 290 to 423 K and 393-510 K for the two configurations, depending on the rf power...
February 2017: Review of Scientific Instruments
Andrew Mezentsev, Nikolai Østgaard, Thomas Gjesteland, Kjetil Albrechtsen, Nikolai Lehtinen, Martino Marisaldi, David Smith, Steven Cummer
A detailed analysis of Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) terrestrial gamma ray flashes (TGFs) is performed in association with World Wide Lightning Location Network (WWLLN) sources and very low frequency (VLF) sferics recorded at Duke University. RHESSI clock offset is evaluated and found to experience changes on the 5 August 2005 and 21 October 2013, based on the analysis of TGF-WWLLN matches. The clock offsets were found for all three periods of observations with standard deviations less than 100 μs...
July 16, 2016: Journal of Geophysical Research. Atmospheres: JGR
D L Campbell, I B Spielman
We theoretically explore a Rashba spin-orbit coupling scheme which operates entirely in the absolute ground state manifold of an alkali atom, thereby minimizing all inelastic processes. An energy gap between ground eigenstates of the proposed coupling can be continuously opened or closed by modifying laser polarizations. Our technique uses far-detuned 'Raman' laser coupling to create the Rashba potential, which has the benefit of low spontaneous emission rates. At these detunings, the Raman matrix elements that link m F magnetic sublevel quantum numbers separated by two are also suppressed...
March 2016: New Journal of Physics
M B Dreval, A M Shapoval, F I Ozherelyev, M M Makhov
An Hα camera has been designed and installed in the U-3M torsatron for spatially and temporally resolved measurements. This device provides fast measurements of the emission brightness profile in the noisy environment of the radio frequency (RF) heated plasma. Unusual topology of diagnostics and the data acquisition system are applied. All the system components, including digitizers, are assembled in a single unit. It allows the suppression of a low-frequency electromagnetic interference by eliminating the ground loops...
July 2016: Review of Scientific Instruments
T R Marsh, B T Gänsicke, S Hümmerich, F-J Hambsch, K Bernhard, C Lloyd, E Breedt, E R Stanway, D T Steeghs, S G Parsons, O Toloza, M R Schreiber, P G Jonker, J van Roestel, T Kupfer, A F Pala, V S Dhillon, L K Hardy, S P Littlefair, A Aungwerojwit, S Arjyotha, D Koester, J J Bochinski, C A Haswell, P Frank, P J Wheatley
White dwarfs are compact stars, similar in size to Earth but approximately 200,000 times more massive. Isolated white dwarfs emit most of their power from ultraviolet to near-infrared wavelengths, but when in close orbits with less dense stars, white dwarfs can strip material from their companions and the resulting mass transfer can generate atomic line and X-ray emission, as well as near- and mid-infrared radiation if the white dwarf is magnetic. However, even in binaries, white dwarfs are rarely detected at far-infrared or radio frequencies...
September 15, 2016: Nature
Davide Barreca, Giorgio Carraro, Alberto Gasparotto, Chiara Maccato, Cinzia Sada, Elza Bontempi, Mariangela Brisotto, Olena Pliekhova, Urška Lavrenčič Štangar
Supported Fe2O3/WO3 nanocomposites were fabricated by an original vapor phase approach, involving the chemical vapor deposition (CVD) of Fe2O3 on Ti sheets and the subsequent radio frequency (RF)-sputtering of WO3. Particular attention was dedicated to the control of the W/Fe ratio, in order to tailor the composition of the resulting materials. The target systems were analyzed by the joint use of complementary techniques, that is, X-ray diffraction (XRD), field emission-scanning electron microscopy (FE-SEM), atomic force microscopy (AFM), energy dispersive X-ray spectroscopy (EDXS), X-ray photoelectron spectroscopy (XPS), secondary ion mass spectrometry (SIMS), and optical absorption spectroscopy...
October 2016: Environmental Science and Pollution Research International
Yong-Xin Liu, Edmund Schüngel, Ihor Korolov, Zoltán Donkó, You-Nian Wang, Julian Schulze
Self-organized spatial structures in the light emission from the ion-ion capacitive rf plasma of a strongly electronegative gas (CF_{4}) are observed experimentally for the first time. Their formation is analyzed and understood based on particle-based kinetic simulations. These "striations" are found to be generated by the resonance between the driving radio frequency and the eigenfrequency of the ion-ion plasma (derived from an analytical model) that establishes a modulation of the electric field, the ion densities, as well as the energy gain and loss processes of electrons in the plasma...
June 24, 2016: Physical Review Letters
V P Veiko, V N Lednev, S M Pershin, A A Samokhvalov, E B Yakovlev, I Yu Zhitenev, A N Kliushin
Double pulse generation mode for nanosecond ytterbium fiber laser was developed. Two sequential 60-200 ns laser pulses with variable delay between them were generated by acousto-optic modulator opening with continuous diode pumping. A custom radio frequency generator was developed to produce two sequential "opening" radio pulses with a delay of 0.2-1 μs. It was demonstrated that double pulse generation did not decrease the average laser power while providing the control over the laser pulse power profile. Surprisingly, a greater peak power in the double pulse mode was observed for the second laser pulse...
June 2016: Review of Scientific Instruments
A Aab, P Abreu, M Aglietta, E J Ahn, I Al Samarai, I F M Albuquerque, I Allekotte, P Allison, A Almela, J Alvarez Castillo, J Alvarez-Muñiz, R Alves Batista, M Ambrosio, A Aminaei, G A Anastasi, L Anchordoqui, S Andringa, C Aramo, F Arqueros, N Arsene, H Asorey, P Assis, J Aublin, G Avila, N Awal, A M Badescu, C Baus, J J Beatty, K H Becker, J A Bellido, C Berat, M E Bertaina, X Bertou, P L Biermann, P Billoir, S G Blaess, A Blanco, M Blanco, J Blazek, C Bleve, H Blümer, M Boháčová, D Boncioli, C Bonifazi, N Borodai, J Brack, I Brancus, T Bretz, A Bridgeman, P Brogueira, P Buchholz, A Bueno, S Buitink, M Buscemi, K S Caballero-Mora, B Caccianiga, L Caccianiga, M Candusso, L Caramete, R Caruso, A Castellina, G Cataldi, L Cazon, R Cester, A G Chavez, A Chiavassa, J A Chinellato, J Chudoba, M Cilmo, R W Clay, G Cocciolo, R Colalillo, A Coleman, L Collica, M R Coluccia, R Conceição, F Contreras, M J Cooper, A Cordier, S Coutu, C E Covault, J Cronin, R Dallier, B Daniel, S Dasso, K Daumiller, B R Dawson, R M de Almeida, S J de Jong, G De Mauro, J R T de Mello Neto, I De Mitri, J de Oliveira, V de Souza, L Del Peral, O Deligny, N Dhital, C Di Giulio, A Di Matteo, J C Diaz, M L Díaz Castro, F Diogo, C Dobrigkeit, W Docters, J C D'Olivo, A Dorofeev, Q Dorosti Hasankiadeh, R C Dos Anjos, M T Dova, J Ebr, R Engel, M Erdmann, M Erfani, C O Escobar, J Espadanal, A Etchegoyen, H Falcke, K Fang, G Farrar, A C Fauth, N Fazzini, A P Ferguson, B Fick, J M Figueira, A Filevich, A Filipčič, O Fratu, M M Freire, T Fujii, B García, D Garcia-Gamez, D Garcia-Pinto, F Gate, H Gemmeke, A Gherghel-Lascu, P L Ghia, U Giaccari, M Giammarchi, M Giller, D Głas, C Glaser, H Glass, G Golup, M Gómez Berisso, P F Gómez Vitale, N González, B Gookin, J Gordon, A Gorgi, P Gorham, P Gouffon, N Griffith, A F Grillo, T D Grubb, F Guarino, G P Guedes, M R Hampel, P Hansen, D Harari, T A Harrison, S Hartmann, J L Harton, A Haungs, T Hebbeker, D Heck, P Heimann, A E Herve, G C Hill, C Hojvat, N Hollon, E Holt, P Homola, J R Hörandel, P Horvath, M Hrabovský, D Huber, T Huege, A Insolia, P G Isar, I Jandt, S Jansen, C Jarne, J A Johnsen, M Josebachuili, A Kääpä, O Kambeitz, K H Kampert, P Kasper, I Katkov, B Keilhauer, E Kemp, R M Kieckhafer, H O Klages, M Kleifges, J Kleinfeller, R Krause, N Krohm, D Kuempel, G Kukec Mezek, N Kunka, A W Kuotb Awad, D LaHurd, L Latronico, R Lauer, M Lauscher, P Lautridou, S Le Coz, D Lebrun, P Lebrun, M A Leigui de Oliveira, A Letessier-Selvon, I Lhenry-Yvon, K Link, L Lopes, R López, A López Casado, K Louedec, A Lucero, M Malacari, M Mallamaci, J Maller, D Mandat, P Mantsch, A G Mariazzi, V Marin, I C Mariş, G Marsella, D Martello, H Martinez, O Martínez Bravo, D Martraire, J J Masías Meza, H J Mathes, S Mathys, J Matthews, J A J Matthews, G Matthiae, D Maurizio, E Mayotte, P O Mazur, C Medina, G Medina-Tanco, R Meissner, V B B Mello, D Melo, A Menshikov, S Messina, M I Micheletti, L Middendorf, I A Minaya, L Miramonti, B Mitrica, L Molina-Bueno, S Mollerach, F Montanet, C Morello, M Mostafá, C A Moura, M A Muller, G Müller, S Müller, S Navas, P Necesal, L Nellen, A Nelles, J Neuser, P H Nguyen, M Niculescu-Oglinzanu, M Niechciol, L Niemietz, T Niggemann, D Nitz, D Nosek, V Novotny, L Nožka, L A Núñez, L Ochilo, F Oikonomou, A Olinto, N Pacheco, D Pakk Selmi-Dei, M Palatka, J Pallotta, P Papenbreer, G Parente, A Parra, T Paul, M Pech, J Pȩkala, R Pelayo, I M Pepe, L Perrone, E Petermann, C Peters, S Petrera, Y Petrov, J Phuntsok, R Piegaia, T Pierog, P Pieroni, M Pimenta, V Pirronello, M Platino, M Plum, A Porcelli, C Porowski, R R Prado, P Privitera, M Prouza, E J Quel, S Querchfeld, S Quinn, J Rautenberg, O Ravel, D Ravignani, D Reinert, B Revenu, J Ridky, M Risse, P Ristori, V Rizi, W Rodrigues de Carvalho, J Rodriguez Rojo, M D Rodríguez-Frías, D Rogozin, J Rosado, M Roth, E Roulet, A C Rovero, S J Saffi, A Saftoiu, H Salazar, A Saleh, F Salesa Greus, G Salina, J D Sanabria Gomez, F Sánchez, P Sanchez-Lucas, E Santos, E M Santos, F Sarazin, B Sarkar, R Sarmento, C Sarmiento-Cano, R Sato, C Scarso, M Schauer, V Scherini, H Schieler, D Schmidt, O Scholten, H Schoorlemmer, P Schovánek, F G Schröder, A Schulz, J Schulz, J Schumacher, S J Sciutto, A Segreto, M Settimo, A Shadkam, R C Shellard, G Sigl, O Sima, A Śmiałkowski, R Šmída, G R Snow, P Sommers, S Sonntag, J Sorokin, R Squartini, Y N Srivastava, D Stanca, S Stanič, J Stapleton, J Stasielak, M Stephan, A Stutz, F Suarez, M Suarez Durán, T Suomijärvi, A D Supanitsky, M S Sutherland, J Swain, Z Szadkowski, O A Taborda, A Tapia, A Tepe, V M Theodoro, C Timmermans, C J Todero Peixoto, G Toma, L Tomankova, B Tomé, A Tonachini, G Torralba Elipe, D Torres Machado, P Travnicek, M Trini, R Ulrich, M Unger, M Urban, J F Valdés Galicia, I Valiño, L Valore, G van Aar, P van Bodegom, A M van den Berg, S van Velzen, A van Vliet, E Varela, B Vargas Cárdenas, G Varner, R Vasquez, J R Vázquez, R A Vázquez, D Veberič, V Verzi, J Vicha, M Videla, L Villaseñor, B Vlcek, S Vorobiov, H Wahlberg, O Wainberg, D Walz, A A Watson, M Weber, K Weidenhaupt, A Weindl, C Welling, F Werner, A Widom, L Wiencke, H Wilczyński, T Winchen, D Wittkowski, B Wundheiler, S Wykes, L Yang, T Yapici, A Yushkov, E Zas, D Zavrtanik, M Zavrtanik, A Zepeda, B Zimmermann, M Ziolkowski, F Zuccarello
We measure the energy emitted by extensive air showers in the form of radio emission in the frequency range from 30 to 80 MHz. Exploiting the accurate energy scale of the Pierre Auger Observatory, we obtain a radiation energy of 15.8±0.7(stat)±6.7(syst)  MeV for cosmic rays with an energy of 1 EeV arriving perpendicularly to a geomagnetic field of 0.24 G, scaling quadratically with the cosmic-ray energy. A comparison with predictions from state-of-the-art first-principles calculations shows agreement with our measurement...
June 17, 2016: Physical Review Letters
Jeremy J Harwood, Judith H Croston, Huib T Intema, Adam J Stewart, Judith Ineson, Martin J Hardcastle, Leith Godfrey, Philip Best, Marisa Brienza, Volker Heesen, Elizabeth K Mahony, Raffaella Morganti, Matteo Murgia, Emanuela Orrú, Huub Röttgering, Aleksandar Shulevski, Michael W Wise
Due to their steep spectra, low-frequency observations of Fanaroff-Riley type II (FR II) radio galaxies potentially provide key insights in to the morphology, energetics and spectrum of these powerful radio sources. However, limitations imposed by the previous generation of radio interferometers at metre wavelengths have meant that this region of parameter space remains largely unexplored. In this paper, the first in a series examining FR IIs at low frequencies, we use LOFAR (LOw Frequency ARray) observations between 50 and 160 MHz, along with complementary archival radio and X-ray data, to explore the properties of two FR II sources, 3C 452 and 3C 223...
June 1, 2016: Monthly Notices of the Royal Astronomical Society
J W Broderick, R P Fender, R P Breton, A J Stewart, A Rowlinson, J D Swinbank, J W T Hessels, T D Staley, A J van der Horst, M E Bell, D Carbone, Y Cendes, S Corbel, J Eislöffel, H Falcke, J-M Grießmeier, T E Hassall, P Jonker, M Kramer, M Kuniyoshi, C J Law, S Markoff, G J Molenaar, M Pietka, L H A Scheers, M Serylak, B W Stappers, S Ter Veen, J van Leeuwen, R A M J Wijers, R Wijnands, M W Wise, P Zarka
The eclipses of certain types of binary millisecond pulsars (i.e. 'black widows' and 'redbacks') are often studied using high-time-resolution, 'beamformed' radio observations. However, they may also be detected in images generated from interferometric data. As part of a larger imaging project to characterize the variable and transient sky at radio frequencies <200 MHz, we have blindly detected the redback system PSR J2215+5135 as a variable source of interest with the Low-Frequency Array (LOFAR). Using observations with cadences of two weeks - six months, we find preliminary evidence that the eclipse duration is frequency dependent (∝ν(-0...
July 1, 2016: Monthly Notices of the Royal Astronomical Society
P Malara, C E Campanella, A Giorgini, S Avino, G Gagliardi
A fiber Bragg grating (FBG)-coupled ring laser sensor is demonstrated. In the proposed configuration the interrogating source, the sensing head and the readout instrument are integrated in a single fiber-optic device. An FBG inserted within a bidirectional fiber ring couples the two counterpropagating modes of the cavity, generating a splitting of the resonant wavelengths proportional to the FBG reflectivity. When the cavity gain is brought beyond threshold, the two peaks of the split resonances simultaneously lase, leading to a beat note in the emission spectrum whose frequency tracks any small shift of the FBG reflectivity spectrum...
April 1, 2016: Optics Letters
Kazuaki Wagatsuma, Kozue Satoh
This paper describes a plasma-diagnostic method using an enhancement factor on the Boltzmann distribution among emission lines of iron atom in an argon radio-frequency inductively-coupled plasma (ICP). It indicated that Boltzmann plots of the atomic lines having lower excitation energies (3.4 to 4.8 eV) were well fitted on a straight line while those having more than 5.5 eV deviated upwards from a linear relationship. This observation could be explained by the fact that ICP is not in a complete thermodynamic equilibrium between direct excitation to energy levels of iron atom, ionization of iron atom, and radiative decay processes to the ground state...
2016: Analytical Sciences: the International Journal of the Japan Society for Analytical Chemistry
R Vaish, R Venkatesh, D A Chaukar, A D Deshmukh, N C Purandare, A K D'cruz
BACKGROUND: Positron emission tomography (PET) forms an integral part in work-up and follow-up of various malignancies. With the increased use of PET in oncology, finding of an incidental focal thyroid uptake (incidentaloma) is not unusual and presents a diagnostic challenge. AIM: The aim of the following study is to evaluate the frequency and radio-pathologic correlation of focal 18-fluoro deoxyglucose uptake (FDG) on PET within the thyroid from a large series...
January 2016: Indian Journal of Cancer
Dirk Jan W Dikken, Jeroen P Korterik, Frans B Segerink, Jennifer L Herek, Jord C Prangsma
Surface plasmon polaritons are electromagnetic waves that propagate tightly bound to metal surfaces. The concentration of the electromagnetic field at the surface as well as the short wavelength of surface plasmons enable sensitive detection methods and miniaturization of optics. We present an optical frequency plasmonic analog to the phased antenna array as it is well known in radar technology and radio astronomy. Individual holes in a thick gold film act as dipolar emitters of surface plasmon polaritons whose phase is controlled individually using a digital spatial light modulator...
2016: Scientific Reports
K Belov, K Mulrey, A Romero-Wolf, S A Wissel, A Zilles, K Bechtol, K Borch, P Chen, J Clem, P W Gorham, C Hast, T Huege, R Hyneman, K Jobe, K Kuwatani, J Lam, T C Liu, J Nam, C Naudet, R J Nichol, B F Rauch, B Rotter, D Saltzberg, H Schoorlemmer, D Seckel, B Strutt, A G Vieregg, C Williams
For 50 years, cosmic-ray air showers have been detected by their radio emission. We present the first laboratory measurements that validate electrodynamics simulations used in air shower modeling. An experiment at SLAC provides a beam test of radio-frequency (rf) radiation from charged particle cascades in the presence of a magnetic field, a model system of a cosmic-ray air shower. This experiment provides a suite of controlled laboratory measurements to compare to particle-level simulations of rf emission, which are relied upon in ultrahigh-energy cosmic-ray air shower detection...
April 8, 2016: Physical Review Letters
P Gebhardt, J Wehner, B Weissler, R Botnar, P K Marsden, V Schulz
The combination of positron emission tomography (PET) and magnetic resonance imaging (MRI) as a multi-modal imaging technique is considered very promising and powerful with regard to in vivo disease progression examination, therapy response monitoring and drug development. However, PET-MRI system design enabling simultaneous operation with unaffected intrinsic performance of both modalities is challenging. As one of the major issues, both the PET detectors and the MRI radio-frequency (RF) subsystem are exposed to electromagnetic (EM) interference, which may lead to PET and MRI signal-to-noise ratio (SNR) deteriorations...
May 7, 2016: Physics in Medicine and Biology
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