Results 101 to 110 of about 109,932 (312)

Effects of high-latitude atmospheric gravity wave disturbances on artificial HF radar backscatter [PDF]

, 2006
International audienceObservations of HF radar backscatter from artificial field-aligned irregularities in an ionosphere perturbed by travelling disturbances due to atmospheric gravity waves are presented.
Tim K. Yeoman (7583066), A. Senior, M. J. Kosch (7595327), I. W. McCrea, M. T. Rietveld (7594184), Rietveld, M. T., Senior, A., T. K. Yeoman, I. W. McCrea (7594871), M. T. Rietveld, Kosch, M. J., M. J. Kosch, A. Senior (3255282), McCrea, I. W., Yeoman, T. K.   +14 more
core   +1 more source

Tropospheric Ducting: A Comprehensive Review and Machine Learning-Based Classification Advancements

IEEE Access
Tropospheric ducts, characterized by anomalous positive vertical refractive index gradients, significantly influence radio wave propagation by enhancing signal strength and extending communication ranges.
Mohammed Banafaa, Ali Hussein Muqaibel
doaj   +1 more source

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

Spacer‐Less Substrate‐Integrated Metasurface for Near‐Unity Terahertz Absorption

Advanced Optical Materials, EarlyView.
ABSTRACT Although conventional metal‐insulator‐metal (MIM) terahertz (THz) absorbers can provide near‐unity absorption, their multilayer stacks inevitably introduce additional thickness, mass, and residual stress, which limit their compatibility with THz thermal sensing platforms.
Zihao Zhao, Kazuho Harada, Qian Liu, Isao Morohashi, Xu Fang, Kazuhiko Hirakawa, Ya Zhang   +6 more
wiley   +1 more source

Digital radio and its application in the HF (2-30 MHz) band [PDF]

, 2004
The propagation environment at high frequencies (HF, 2-30 MHz) has a significant impact on the performance of radio systems (especially data communications).
Davies, Nigel Clement
core  

Correlation between cosmic noise absorption and VHF coherent echo intensity [PDF]

, 2005
International audienceWe present examples and statistical analysis of the events with statistically significant correlation between the cosmic noise absorption (CNA) and the signal-to-noise ratio (SNR) of the VHF coherent echo intensity in the area ...
Makarevitch, R.A., Makarevitch, R. A., F. Honary, Honary, F., R. A. Makarevitch   +4 more
core   +1 more source

Sub-Gigahertz Path Loss Measurement Campaign in Marine Environment: A Case Study

Sensors
This paper focuses on the characterization of radio propagation, and data communication in a marine environment. More specifically, we consider signal propagation when three different sub-gigahertz industrial, scientific, and medical (ISM) bands, i.e ...
Marco De Piante, Michele Midrio, Roberto Rinaldo, Ivan Scagnetto, Ruben Specogna, Francesco Trevisan   +5 more
doaj   +1 more source

Neodymium‐Doped Nanocrystals for Sensing Cellular Temperature at the Nanoscale

Advanced Optical Materials, EarlyView.
Neodymium‐doped NaYF4 nanocrystals are engineered as bright, biocompatible nanothermometers for intracellular temperature mapping. Their ratiometric near‐infrared emission enables highly sensitive, nanoscale thermal readouts in living cells. Combined with gold nanostars for photothermal therapy, they reveal pronounced subcellular heating heterogeneity ...
Maria Bravo, Sandra Krzyzowska, Shelly Yang, Dingchen Wen, Jana Zielinski, Farsai Taemaitree, Samantha Zaman, Alastair Stewart, Susana Rocha, Paul Mulvaney, Hiroshi Uji‐i, Beatrice Fortuni, Sam Brooke, James Hutchison   +13 more
wiley   +1 more source

Study of millimeter wave phase shift in 40 GHz hybrid mode locked lasers [PDF]

, 2009
An investigation into using hybrid mode-locked lasers to implement millimeter wave phase shift is presented. The phase shift is measured directly using a vector network analyzer enabling straightforward characterization of such systems.
Cryan, MJ, Khawaja, BAM
core   +1 more source

Color Center Formation in Silicon‐On‐Insulator for On‐Chip Photonic Integration

Advanced Optical Materials, EarlyView.
ABSTRACT Color centers in silicon have great potential as single photon sources for quantum technologies. Some of them – like the T center – also possess optically‐active spins that enable spin‐photon interfaces for generating entangled photons and multi‐spin registers. This paper explores the generation of several types of color centers in silicon for
Arnulf J. Snedker‐Nielsen, David R. Gongora, Magnus L. Madsen, Christian H. Christiansen, Eike L. Piehorsch, Mathias Ø. Augustesen, Elvedin Memisevic, Sangeeth Kallatt, Rodrigo A. Thomas, Mark K. Svendsen, James L. Webb, Peter K. Jeppesen, Marianne E. Bathen, Lasse Vines, Peter Granum, Stefano Paesani   +15 more
wiley   +1 more source