Interstellar Silicon−Nitrogen Chemistry. 2. Spectral Signatures of the SiNH2+Molecular Ion

AbstractDipole emission pattern imaging experiments on single chains of common conjugated polymers (solubilized poly phenylene vinylenes) isolated by ink-jet printing techniques have revealed surprising uniformity in transition moment orientation perpendicular to the support substrate. In addition to uniform orientation, these species show a number of striking differences in photochemical stability, polarization anisotropy,[1] and spectral signatures[2] with respect to similar (well-studied) molecules dispersed in dilute thin-films. Combined with molecular mechanics simulation, these results point to a structural picture of a folded macromolecule as a highly ordered cylindrical nanostructure whose long-axis (approximately collinear with the conjugation axis) is oriented, by an electrostatic interaction, perpendicular to the coverglass substrate. These results suggest a number of important applications in nanoscale photonics and molecular-scale optoelectronics.

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Photon Emission Spectral Signatures of AlGaN/GaN HEMT for Functional and Reliability Analysis

ISTFA 2008: Conference Proceedings from the 34th International Symposium for Testing and Failure Analysis ◽

10.31399/asm.cp.istfa2008p0220 ◽

2008 ◽

Author(s):

Arkadiusz Glowacki ◽

Christian Boit ◽

Richard Lossy ◽

Joachim Würfl

Keyword(s):

Reliability Analysis ◽

Gate Voltage ◽

Near Infrared ◽

Photon Emission ◽

Electrical Characterization ◽

Spectral Signatures ◽

Operating Modes ◽

Gan Hemt ◽

Spectrally Resolved ◽

Performance Variations

Abstract Non-degraded and degraded AlGaN/GaN HEMT devices have been characterized electrically and investigated in various operating modes using integral and spectrally resolved photon emission (PE). In degraded devices the PE dependence on the gate voltage differs from the non-degraded devices. Various types of dependencies on the gate voltage have been identified when investigating local degradation sites. PE spectroscopy was performed at various bias conditions. For both devices broad spectra have been obtained in a wavelength regime from visible to near-infrared, including local performance variations. Signatures of the degradation have been determined in the electrical characterization, in integral PE distribution and in the PE spectrum.

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Science of Land Target Spectral Signatures

10.21236/ada575755 ◽

2013 ◽

Author(s):

J. M. Cathcart

Keyword(s):

Spectral Signatures

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Optical and Radar Data Analysis for Land Use Land Cover Mapping in Peru

10.21523/gcj1.19030102 ◽

2019 ◽

Vol 3 (1) ◽

pp. 14-27

Author(s):

Barry Haack ◽

Ron Mahabir

Keyword(s):

Land Use ◽

Land Cover ◽

Window Size ◽

Radar Data ◽

Optical Data ◽

Land Cover Mapping ◽

Land Use Land Cover ◽

Texture Image ◽

Site Class ◽

Spectral Signatures

This analysis determined the best individual band and combinations of various numbers of bands for land use land cover mapping for three sites in Peru. The data included Landsat Thematic Mapper (TM) optical data, PALSAR L-band dual-polarized radar, and derived radar texture images. Spectral signatures were first obtained for each site class and separability between classes determined using divergence measures. Results show that the best single band for analysis was a TM band, which was different for each site. For two of the three sites, the second best band was a radar texture image from a large window size. For all sites the best three bands included two TM bands and a radar texture image. The original PALSAR bands were of limited value. Finally upon further analysis it was determined that no more than six bands were needed for viable classification at each study site.

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Imaging and SERS Study of the Au Nanoparticles Interaction with HPV and Carcinogenic Cervical Tissues

Molecules ◽

10.3390/molecules26123758 ◽

2021 ◽

Vol 26 (12) ◽

pp. 3758

Author(s):

Andrea Ceja-Fdez ◽

Ramon Carriles ◽

Ana Lilia González-Yebra ◽

Juan Vivero-Escoto ◽

Elder de la Rosa ◽

...

Keyword(s):

Multiphoton Microscopy ◽

Surface Enhanced Raman Spectroscopy ◽

Rapid Screening ◽

Emission Region ◽

Sem Images ◽

Spectral Signatures ◽

Two Photon ◽

Surface Enhanced ◽

Surface Enhanced Raman ◽

Gold Nps

In this work, gold NPs were prepared by the Turkevich method, and their interaction with HPV and cancerous cervical tissues were studied by scanning electron microscopy, energy-dispersive x-ray spectroscopy, confocal and multiphoton microscopy and SERS. The SEM images confirmed the presence and localization of the gold NPs inside of the two kinds of tissues. The light absorption of the gold NPs was at 520 nm. However, it was possible to obtain two-photon imaging (red emission region) of the gold NPs inside of the tissue, exciting the samples at 900 nm, observing the morphology of the tissues. The infrared absorption was probably due to the aggregation of gold NPs inside the tissues. Therefore, through the interaction of gold nanoparticles with the HPV and cancerous cervical tissues, a surface enhanced Raman spectroscopy (SERS) was obtained. As preliminary studies, having an average of 1000 Raman spectra per tissue, SERS signals showed changes between the HPV-infected and the carcinogenic tissues; these spectral signatures occurred mainly in the DNA bands, potentially offering a tool for the rapid screening of cancer.

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