Science of Land Target Spectral Signatures

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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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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Spectral signatures of soil horizons and soil orders – An exploratory study of 270 soil profiles

Geoderma ◽

10.1016/j.geoderma.2021.114961 ◽

2021 ◽

Vol 389 ◽

pp. 114961

Author(s):

Yakun Zhang ◽

Alfred E. Hartemink ◽

Jingyi Huang

Keyword(s):

Exploratory Study ◽

Soil Profiles ◽

Soil Horizons ◽

Spectral Signatures

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Development of Calibration Models to Predict Mean Fibre Diameter in Llama (Lama glama) Fleeces with Near Infrared Spectroscopy

Animals ◽

10.3390/ani11071998 ◽

2021 ◽

Vol 11 (7) ◽

pp. 1998

Author(s):

José Ignacio Amorena ◽

Dolores María Eugenia Álvarez ◽

Elvira Fernández-Ahumada

Keyword(s):

Textile Industry ◽

Near Infrared ◽

Prediction Models ◽

External Validation ◽

Fibre Diameter ◽

Near Infrared Reflectance ◽

Screening Programs ◽

Spectral Signatures ◽

Calibration Models ◽

Cross Validation Error

Llama fibre has the potential to become the most valuable textile resource in the Puna region of Argentina. In this study near infrared reflectance spectroscopy was evaluated to predict the mean fibre diameter in llama fleeces. Analyses between sets of carded and non-carded samples in combination with spectral preprocessing techniques were carried out and a total of 169 spectral signatures of llama samples in Vis and NIR ranges (400–2500 nm) were obtained. Spectral preprocessing consisted in wavelength selection (Vis–NIR, NIR and discrete ranges) and multiplicative and derivative pretreatments; spectra without pretreatments were also included, while modified partial least squares (M-PLS) regression was used to develop prediction models. Predictability was evaluated through R2: standard cross validation error (SECV), external validation error (SEV) and residual predictive value (RPD). A total of 54 calibration models were developed in which the best model (R2 = 0.67; SECV = 1.965; SEV = 2.235 and RPD = 1.91) was obtained in the Vis–NIR range applying the first derivative pretreatment. ANOVA analysis showed differences between carded and non-carded sets and the models obtained could be used in screening programs and contribute to valorisation of llama fibre and sustainable development of textile industry in the Puna territory of Catamarca. The data presented in this paper are a contribution to enhance the scarce information on this subject.

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Nonnegative matrix factorization for hyperspectral unmixing using prior knowledge of spectral signatures

Optical Engineering ◽

10.1117/1.oe.51.8.087001 ◽

2012 ◽

Vol 51 (8) ◽

pp. 087001 ◽

Cited By ~ 16

Author(s):

Wei Tang

Keyword(s):

Prior Knowledge ◽

Matrix Factorization ◽

Nonnegative Matrix Factorization ◽

Nonnegative Matrix ◽

Spectral Signatures ◽

Hyperspectral Unmixing

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On the Spectral and Polarimetric Signatures of a Bright Scatterer before and after Hardware Replacement

Remote Sensing ◽

10.3390/rs13050919 ◽

2021 ◽

Vol 13 (5) ◽

pp. 919

Author(s):

Marco Gabella

Keyword(s):

Low Noise ◽

Low Noise Amplifiers ◽

Doppler Velocity ◽

Data Set ◽

Differential Phase Shift ◽

Spectral Signatures ◽

Average Value ◽

Before And After ◽

Radar Calibration ◽

Small Dispersion

A previous study has used the stable and peculiar echoes backscattered by a single “bright scatterer” (BS) during five winter days to characterize the hardware of C-band, the dual-polarization radar located at Monte Lema (1625 m altitude) in Southern Switzerland. The BS is the 90 m tall metallic tower on Cimetta (1633 m altitude, 18 km range). In this note, the statistics of the echoes from the BS were derived from other ten dry days with normal propagation conditions in winter 2015 and January 2019. The study confirms that spectral signatures, such as spectrum width, wideband noise and Doppler velocity, were persistently stable. Regarding the polarimetric signatures, the large values (with small dispersion) of the copolar correlation coefficient between horizontal and vertical polarization were also confirmed: the average value was 0.9961 (0.9982) in winter 2015 (January 2019); the daily standard deviations were very small, ranging from 0.0007 to 0.0030. The dispersion of the differential phase shift was also confirmed to be quite small: the daily standard deviation ranged from a minimum of 2.5° to a maximum of 5.3°. Radar reflectivities in both polarizations were typically around 80 dBz and were confirmed to be among the largest values observed in the surveillance volume of the Monte Lema radar. Finally, another recent 5-day data set from January 2020 was analyzed after the replacement of the radar calibration unit that includes low noise amplifiers: these five days show poorer characteristics of the polarimetric signatures and a few outliers affecting the spectral signatures. It was shown that the “historical” polarimetric and spectral signatures of a bright scatterer could represent a benchmark for an in-depth comparison after hardware replacements.

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