Porphyrins and flavins as endogenous acceptors of optical radiation of blue spectral region determining photoinactivation of microbial cells

Highly efficient Tb3+/Eu3+ energy transfer was observed in red emitting Tb2Mo3O12 powders and ceramics. It possesses an increased absorption in the UV-A/blue spectral region with an excellent QE of 94%. It is superior in efficacy to red emitters like Sr2Si5N8:Eu and CaAlSiN3:Eu. Transfer rates were calculated from rise times employing a newly developed method.

Download Full-text

Analysis of ACAM Data for Trace Gas Retrievals during the 2011 DISCOVER-AQ Campaign

Journal of Spectroscopy ◽

10.1155/2015/827160 ◽

2015 ◽

Vol 2015 ◽

pp. 1-7 ◽

Cited By ~ 2

Author(s):

C. Liu ◽

X. Liu ◽

M. G. Kowalewski ◽

S. J. Janz ◽

G. González Abad ◽

...

Keyword(s):

Spectral Resolution ◽

Spectral Region ◽

Total Ozone ◽

Signal To Noise Ratio ◽

Trace Gas ◽

System Throughput ◽

Signal To Noise ◽

Ozone Profile ◽

Blue Spectral Region ◽

Large Wavelength

To improve the trace gas retrieval from Airborne Compact Atmospheric Mapper (ACAM) during the DSICOVER-AQ campaigns, we characterize the signal to noise ratio (SNR) of the ACAM measurement. From the standard deviations of the fitting residuals, the SNRs of ACAM nadir measurements are estimated to vary from ~300 at 310 nm to ~1000 in the blue spectral region; the zenith data are noisier due to reduced levels of illumination and lower system throughput and also show many more pixels with abrupt anomalous values; therefore, a new method is developed to derive a solar irradiance reference at the top of the atmosphere (TOA) from average nadir measurements, at instrument spectral resolution and including instrument calibration characteristics. Using this reference can significantly reduce fitting residuals and improve the retrievals. This approach derives an absolute reference for direct fitting algorithms involving radiative transfer calculations and thus can be applied to both aircraft and ground-based measurements. The comparison of ACAM radiance with simulations using coincident ozonesonde and OMI data shows large wavelength-dependent biases in ACAM data, varying from ~−19% at 310 nm to 5% at 360 nm. Correcting ACAM radiance in direct-fitting based ozone profile algorithm significantly improves the consistency with OMI total ozone.

Download Full-text

High gain bipolar junction phototransistors with finger-shaped emitter for improved optical gas sensing in the blue spectral region

Sensors and Actuators A Physical ◽

10.1016/j.sna.2006.12.025 ◽

2007 ◽

Vol 136 (2) ◽

pp. 588-596 ◽

Cited By ~ 6

Author(s):

Arianna Tibuzzi ◽

Gian-Franco Dalla Betta ◽

Claudio Piemonte ◽

Corrado Di Natale ◽

Arnaldo D’Amico ◽

...

Keyword(s):

Spectral Region ◽

Gas Sensing ◽

High Gain ◽

Optical Gas Sensing ◽

Blue Spectral Region

Download Full-text

Frequency-tunable 500-mW continuous-wave all-solid-state single-frequency source in the blue spectral region

Optics Letters ◽

10.1364/ol.22.001220 ◽

1997 ◽

Vol 22 (16) ◽

pp. 1220 ◽

Cited By ~ 35

Author(s):

M. Bode ◽

I. Freitag ◽

A. Tünnermann ◽

H. Welling

Keyword(s):

Solid State ◽

Spectral Region ◽

Continuous Wave ◽

Single Frequency ◽

Frequency Source ◽

Frequency Tunable ◽

Blue Spectral Region

Download Full-text

Evolution of Ocean Color Atmospheric Correction: 1970–2005

Remote Sensing ◽

10.3390/rs13245051 ◽

2021 ◽

Vol 13 (24) ◽

pp. 5051

Author(s):

Howard R. Gordon

Keyword(s):

Coastal Waters ◽

Spectral Region ◽

Ocean Color ◽

Atmospheric Correction ◽

Visible Region ◽

Coastal Areas ◽

Open Ocean ◽

Water Properties ◽

Blue Spectral Region ◽

Global Data

Retrieval of water properties from satellite-borne imagers viewing oceans and coastal areas in the visible region of the spectrum requires removing the effect of the atmosphere, which contributes approximately 80–90% of the measured radiance over the open ocean in the blue spectral region. The Gordon and Wang algorithm originally developed for SeaWiFS (and used with other NASA sensors, e.g., MODIS) forms the basis for many atmospheric removal (correction) procedures. It was developed for application to imagery obtained over the open ocean (Case 1 waters), where the aerosol is usually non-absorbing, and is used operationally to process global data from SeaWiFS, MODIS and VIIRS. Here, I trace the evolution of this algorithm from early NASA aircraft experiments through the CZCS, OCTS, SeaWiFs, MERIS, and finally the MODIS sensors. Strategies to extend the algorithm to situations where the aerosol is strongly absorbing are examined. Its application to sensors with additional and unique capabilities is sketched. Problems associated with atmospheric correction in coastal waters are described.

Download Full-text