Results 51 to 60 of about 35,279 (308)

Exciton Radiative Lifetimes in Hexagonal Diamond Ge and SixGe1–x Alloys

Advanced Optical Materials, EarlyView.
Strong room‐temperature photoluminescence reported in hexagonal Ge conflicts with theory predicting a nearly dark band edge. First‐principles calculations of excitonic radiative lifetimes fill a key gap in this debate, showing that pristine hexagonal Ge remains intrinsically weakly emissive, while Si alloying only modestly shortens the lifetime and ...
Michele Re Fiorentin, Michele Amato, Maurizia Palummo   +2 more
wiley   +1 more source

A Study on Satellite Diagnostic Expert Systems Using Case-Based Approach [PDF]

Journal of Astronomy and Space Sciences, 1997
Many research works are on going to monitor and diagnose diverse malfunctions of satellite systems as the complexity and number of satellites increase. Currently, many works on monitoring and diagnosis are carried out by human experts but there are needs
Young-Tack Park, Jaehoon Kim, Hyunsoo Park   +2 more
doaj  

Luminescence and Photochromism in Lanthanide‐Doped Hackmanites

Advanced Optical Materials, EarlyView.
Lanthanide‐doped lithium hackmanite derivatives are prepared utilizing a doped LiAlSiO4 precursor to modify luminescent and photochromic properties. Upon UV excitation, europium doping results in green Eu2+ persistent luminescence from shallow traps. Contrarily, samarium doping induces unusual near‐infrared photochromism.
Joshua Baggott, Minnea Tuomisto, J. A. Gareth Williams, Sari Granroth, Ermei Mäkilä, Ari Väisänen, Jani O. Moilanen, Mika Lastusaari   +7 more
wiley   +1 more source

DVB-RCS return link radio resource management for broadband satellite systems using fade mitigation techniques at ka band [PDF]

, 2008
Current Broadband Satellite systems supporting DVB-RCS at Ku band have static physical layer in order not to complicate their implementation. However at Ka band frequencies and above an adaptive physical layer wherein the physical layer parameters are ...
Laurent Castanet, Bousquet, Michel, Jose Radzik, Michel Bousquet, Aroumont, Anbazhagan, Radzik, José, Anbazhagan Aroumont, Castanet, Laurent   +7 more
core   +1 more source

Exploring the Synergy of Combining BINAP and tCzBN Motifs Within Multi‐Resonant TADF Emitters to Enhance OLED Performance

Advanced Optical Materials, EarlyView.
This work presents two MR‐TADF emitters, BINAP‐BN1 and BINAP‐BN2, based on a BINAP core and differing numbers of tCzBN units. Both emitters show similar solution photophysics, but distinct behavior in doped films, where BINAP‐BN1 exhibits higher photoluminescence quantum yield and suppressed aggregation‐induced emission broadening compared to BINAP‐BN2.
John Marques dos Santos, Debasish Barman, Rangani Wathsala Weerasinghe, Tomas Matulaitis, David B. Cordes, Aidan P. McKay, Youichi Tsuchiya, Chihaya Adachi, Eli Zysman‐Colman   +8 more
wiley   +1 more source

On the Achievable Rates for the Return-Link of Multi-Beam Satellite Systems Using Successive Interference Cancellation

, 2011
This paper investigates the theoretically reachable rates in the return-link of multi-user multi-beam satellite systems. The return-link can actually be analyzed by means of multiple-input multiple-output signal processing techniques. While MIMO inspired
Michael Joham, Matteo Berioli, Rossetto, Francesco, Francesco Rossetto, Boussemart, Vincent, Berioli, Matteo, Joham, Michael, Vincent Boussemart   +7 more
core   +1 more source

Group size estimation for hybrid satellite/terrestrial reliable multicast [PDF]

, 2004
This paper addresses the problem of group size estimation for hybrid satellite/terrestrial multipoint communications. Estimators based on the maximum likelihood principle are investigated.
L. Dairaine, Fraboul, Christian, Dairaine, Laurent, Tourneret, Jean-Yves, F. de Belleville, J.Y. Tourneret, De Belleville, Florestan, C. Fraboul   +7 more
core   +1 more source

Mitigating Efficiency Roll‐Off in Phosphor‐Sensitized Fluorescence OLEDs via Molecular Polarity‐Based Benzofuropyridine Host Engineering

Advanced Optical Materials, EarlyView.
Positional isomerism in dibenzofuran‐based n‐type hosts modulates molecular polarity, charge‐transport balance, and emissive‐layer packing. The higher‐polarity BFPDB‐2 host facilitates efficient energy funneling, reduced aggregation, and preferential dipole orientation, leading to phosphor‐sensitized fluorescence OLEDs with enhanced external quantum ...
Nargis Ali, Xuyao Song, Yun‐Hi Kim, Min Chul Suh   +3 more
wiley   +1 more source

NORAD TLE Conversion from Osculating Orbital Element [PDF]

Journal of Astronomy and Space Sciences, 2002
The NORAD type Two Line Element (TLE) was obtained from the osculating orbital elements by an iterative approximation procedure. The mathematical model was presented and computer program was developed for the conversion.
Byoung-Sun Lee
doaj   +1 more source

A delay model for satellite constellation networks with inter-satellite links

, 2009
Within this paper we examine a non-geostationary satellite constellation network with inter-satellite links (ISLs) for global air traffic control (ATC) and air passenger communication (APC).
Romain Hermenier, Anton Donner, Kißling, Christian, Donner, Anton, Hermenier, Romain, Christian Kissling   +5 more
core   +1 more source