نتایج جستجو برای: brightness temperature

تعداد نتایج: 466684  

Journal: :Journal of physics 2022

Abstract In our time, plasma physics is a hot topic of research. During the movement hypersonic aircraft, main physical phenomenon, which radically affects conditions for propagation electromagnetic waves in its vicinity formation shell around apparatus due to ionization neutral particles. When measuring radio-brightness temperature and electrons, it necessary take into account measurement erro...

2011
K. Andrea Scott Mark Buehner Alain Caya Tom Carrieres

In this paper a method to directly assimilate brightness temperatures from the Advanced Microwave Scanning Radiometer (AMSR-E) to produce ice concentration analyses within a three-dimensional variational data assimilation system is investigated. To assimilate the brightness temperatures a simple radiative transfer model is used as the forward model which maps the state vector to the observation...

2009
ASHOK K. SINGAL

We show that an upper limit of ∼ 10 K on the peak brightness temperature for an incoherent synchrotron radio source, commonly referred to in the literature as an inverse Compton limit, may not really be due to inverse Compton effects. We show that a somewhat tighter limit Teq ∼ 10 11 is actually obtained for the condition of equipartition of energy between radiating particles and magnetic field...

2017
AV Steele A Schwarzkopf JJ McClelland B Knuffman

We present measurements of focal spot size and brightness in a focused ion beam system utilizing a laser-cooled atomic beam source of Cs ions. Spot sizes as small as (2.1 ± 0.2) nm (one standard deviation) and reduced brightness values as high as (2.4 ± 0.1) × 107 A m-2 Sr-1 eV-1 are observed with a 10 keV beam. This measured brightness is over 24 times higher than the highest brightness observ...

Journal: :Physical review letters 2005
Niels de Jonge Myriam Allioux Jim T Oostveen Kenneth B K Teo William I Milne

The figure of merit for the electron optical performance of carbon-nanotube (CNT) electron sources is presented. This figure is given by the relation between the reduced brightness and the energy spread in the region of stable emission. It is shown experimentally that a CNT electron source exhibits a highly stable emission process that follows the Fowler-Nordheim theory for field emission, fixi...

Journal: :Evolution; international journal of organic evolution 2009
Carita Lindstedt Leena Lindström Johanna Mappes

Evolution of conspicuous signals may be constrained if animal coloration has nonsignaling as well as signaling functions. In aposematic wood tiger moth (Parasemia plantaginis) larvae, the size of a warning signal (orange patch on black body) varies phenotypically and genetically. Although a large warning signal is favored as an antipredator defense, we hypothesized that thermoregulation may con...

2007
Steven R. Furlanetto Michael R. Furlanetto

The spin temperature of neutral hydrogen, which determines the optical depth and brightness of the 21 cm line, is determined by the competition between radiative and collisional processes. Here we examine the role of proton-hydrogen collisions in setting the spin temperature. We use recent fully quantum-mechanical calculations of the relevant cross sections, which allow us to present accurate r...

2016
Bryan Hally Luke Wallace Karin Reinke Simon Jones

Fire detection from satellite sensors relies on an accurate estimation of the unperturbed state of a target pixel, from which an anomaly can be isolated. Methods for estimating the radiation budget of a pixel without fire depend upon training data derived from the location’s recent history of brightness temperature variation over the diurnal cycle, which can be vulnerable to cloud contamination...

2009
A. Devasthale

A daytime climatological spatio-temporal distribution of high opaque ice cloud (HOIC) classes over the Indian subcontinent (0–40 N, 60 E–100 E) is presented using 25-year data from the Advanced Very High Resolution Radiometers (AVHRRs) for the summer monsoon months. The HOICs are important for regional radiative balance, precipitation and troposphere-stratosphere exchange. In this study, HOICs ...

Journal: :Nanoscale 2015
Aqiang Wang Huaibin Shen Shuaipu Zang Qingli Lin Hongzhe Wang Lei Qian Jinzhong Niu Lin Song Li

In this paper, highly stable violet-blue emitting ZnSe/ZnS core/shell QDs have been synthesized by a novel "low temperature injection and high temperature growth" method. The resulting nearly monodisperse ZnSe/ZnS core/shell QDs exhibit excellent characteristics such as a high color saturation (typical spectral full width at half-maximum between 12 and 20 nm), good emission tunability in the vi...

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