Search results for "Gall"
showing 10 items of 903 documents
Internal photoemission in solar blind AlGaN Schottky barrier photodiodes
2005
We have analyzed the photoresponse of solar blind AlGaN Schottky barrier photodiodes below the alloy band gap energy, in the 3.5-4.5 eV range, and we show that it is dominated by internal photoemission. The n-type Schottky barrier height is shown to increase linearly with the band gap energy of the AlGaN alloy. The amplitude of the internal photoemission signal is about 20 times smaller than the value given by the Fowler theory based on a free electron model. We explain this result by taking into account the interband transitions and the ballistic transport of photoexcited electrons in the metal. This low value of internal photoemission allows us to achieve a spectral rejection ratio betwee…
Between Paris and Geneva: Some Remarks on the Approval of the Gallican Confession (May 1559)
2018
Questo articolo analizza l'approvazione della Confessione gallicana durante il cosiddetto primo sinodo nazionale delle Chiese riformate francesi, tenutosi a Parigi nel maggio 1559. Il consenso stabilito è che Calvino abbia avuto un ruolo da protagonista nell'adozione della Confessione da parte dei pastori riuniti a Parigi. Si ritiene che questi ultimi abbiano modificato e promulgato la Confessione gallicana sulla base di una bozza che il primo aveva scritto e inviato al sinodo. Questo documento metterà alla prova l'ipotesi che Calvino non abbia mai inviato alcuna bozza a Parigi per l'approvazione nel maggio 1559 e che un documento parigino del 1557, la lettera-confessione Au Roy, sia stato …
Frequency comb generation in whispering gallery mode silica microsphere resonators
2021
Optical frequency combs (OFC) using different kinds of whispering-gallery-mode (WGM) microresonators have already shown different applications and especially their applications in fiber optical communication systems as replacements of laser-arrays. For this application the free spectral range (FSR) of 200 GHz or less is desirable. Besides the fabrication material for microspheres, the resonator radius can be modified to change the FSR. In this paper use of silica microspheres for OFC represents an inexpensive alternative over the other microcombs: microring, microdisk, and microtoroid. We experimentally present a microsphere fabrication process from a different kind of silica (SiO2) fibers …
L'INDIRIZZO PAIDEUTICO DI UN MAESTRO DELL'ANTICO MONACHESIMO: AD QUARTUM ... PERVENIRE (CASSIAN., CONL., 3,10)
2008
Nella paideia monastica di Giovanni Cassiano, cui si è richiamato nel tardo impero romano tutto il monachesimo occidentale e in particolare quello gallico e provenzale (S. Pricoco, V. Messana), si rintracciano e si focalizzano quattro gradi o momenti, fasi o tappe di progresso nel cammino di perfezione, tutti e quattro rispettivamente e parallelamente fondati sui quattro sensi della Scrittura (historia, tropologia, allegoria, anagogia), e ancorati ai quattro tipi dell''eucologia paolina di 1Tim. 2,1 (obsecratio, oratio, postulatio, gratiarum actio).
Synthesis of Silver Gallium Selenide (AgGaSe2) Nanotubes and Nanowires by Template-Based Electrodeposition
2020
In this work, a systematic investigation of the different parameters that control the electrodeposition processes was carried out at the aim to synthetizing AgGaSe₂ nanostructures. We found that pH is a key parameter to control both the morphology and composition of the nanostructures. Low pH favours mainly the formation of Ag2Se nanotubes with a scarce mechanical stability, while multi-phase nanowires well anchored to the substrate were obtained at higher pH. We also found that it was necessary to increase dramatically the concentration of the gallium precursor into the deposition bath in order to obtain AgGaSe₂ owing to lower redox potential of the Ga3+/Ga couple than Ag2+/Ag and Se4+/Se.…
Multiexciton complex from extrinsic centers in AlGaAs epilayers on Ge and Si substrates
2013
The multiexciton properties of extrinsic centers from AlGaAs layers on Ge and Si substrates are addressed. The two photon cascade is found both in steady state and in time resolved experiments. Polarization analysis of the photoluminescence provides clearcut attribution to neutral biexciton complexes. Our findings demonstrate the prospect of exploiting extrinsic centers for generating entangled photon pairs on a Si based device. © 2013 AIP Publishing LLC.
Indium surfactant effect on AlN/GaN heterostructures grown by metal-organic vapor-phase epitaxy: Applications to intersubband transitions
2006
We report on a dramatic improvement of the optical and structural properties of AlN/GaN multiple quantum wells (MQWs) grown by metal-organic vapor-phase epitaxy using indium as a surfactant. This improvement is observed using photoluminescence as well as x-ray diffraction. Atomic force microscopy shows different surface morphologies between samples grown with and without In. This is ascribed to a modified relaxation mechanism induced by different surface kinetics. These improved MQWs exhibit intersubband absorption at short wavelength (2 mu m). The absorption linewidth is as low as 65 meV and the absorption coefficient is increased by 85%.
Mid-infrared intersubband absorption in lattice-matched AlInN/GaN multiple-quantum wells
2005
We report the observation of midinfrared intersubband (ISB) absorption in nearly lattice-matched AlInNGaN multiple-quantum-wells. A clear absorption peak is observed around 3 μm involving transitions from the conduction band ground state to the first excited state. In addition to ISB absorption, photoluminescence experiments were carried out on lattice- matched AlInNGaN single quantum wells in order to determine the spontaneous polarization discontinuity between GaN and Al0.82 In0.18 N compounds. The experimental value is in good agreement with theoretical predictions. Our results demonstrate that the AlInNGaN system is very promising to achieve crack-free and low dislocation density struct…
New records of gall-inducer and inquiline insects in a few mediterranean countries, with biological notes
2014
An annotated list of some gall-inducing and inquiline insects found on herbaceous plants and trees in Italy and in other few Mediterranean countries is reported. Among the gall-inducer species, Phanacis phoenixopodos (Mayr, 1882) is new for the Italian peninsula, Callirhytis rufescens (Mayr, 1882), Andricus quercusramuli (L., 1761) and Plagiotrochus amenti Kieffer, 1901 (Cynipidae: Hymenoptera) are new for Sicily; the latter was previously cited from Italy without collecting data. Oecocecis guyonella Guenée, 1870 was found in Libya and Amblypalpis olivierella Ragonot, 1886 (Gelechiidae: Lepidoptera) in Jordan, Libya, Northern Yemen, and the United Arab Emirates. In addition, Saphonecrus gal…
Conflitti religiosi al tempo di Galla Placidia e Costanzo. A proposito di Olimpiodoro fr. 15 M
2010
L’articolo analizza alcuni frammenti olimpiodorei relativi alla lotta contro il paganesimo nell’età di Galla Placidia e Costanzo III. Il fr. 15 Müller delle Storie di Olimpiodoro narra la distruzione di un antico idolo pagano, che proteggeva la Sicilia dalle eruzioni dell’Etna e dalle incursioni, ad opera dell’amministratore dei beni siciliani della coppia imperiale. Stando allo storico tebano, l’abbattimento della statua, che aveva evitato lo sbarco dei Goti di Alarico nel 410, avrebbe comportato gravi conseguenze per l’isola, soggetta a partire da quel momento alle invasioni barbariche ed alla violenta attività del vulcano. Negli anni di Galla Placidia e Costanzo si dovette aprire una nuo…