CO2 transverse excitation laser induced photochemical enrichment of carbon isotopes

1976 ◽  
pp. 811 ◽  
Author(s):  
Joseph J. Ritter ◽  
Samuel M. Freund
Keyword(s):  
Carbon Isotopes ◽  
Transverse Excitation ◽  
Excitation Laser

Carbon isotopes in Sphagnum from Kyushu, Japan, and their relationship with local climate

2015 ◽  
Vol 49 (5) ◽  
pp. 495-502 ◽  
Author(s):  
Saki Yasuda ◽  
Seigo Ooki ◽  
Hiroshi Naraoka ◽  
Tasuku Akagi
Keyword(s):  
Carbon Isotopes ◽  
Local Climate

THERMAL ALTERATION OF PRECAMBRIAN MICROFOSSILS: APPLICATIONS TO THE STUDY OF STABLE CARBON ISOTOPES ON THE EARLY EARTH

2020 ◽  
Author(s):  
Jeffrey Osterhout ◽  
◽  
J. William Schopf ◽  
Anatoliy B. Kudryavtsev ◽  
K.D. McKeegan
Keyword(s):  
Carbon Isotopes ◽  
Stable Carbon Isotopes ◽  
Early Earth ◽  
Stable Carbon ◽  
Thermal Alteration

scholarly journals Unusual Polarization Relation between Single-Mode Lasing Emission and Excitation Laser from an Evanescent-Wave Pumped Micro-Cavity Laser

Photonics ◽  
2021 ◽  
Vol 8 (3) ◽  
pp. 66
Author(s):  
Yuchen Wang ◽  
Hongsheng Li ◽  
Shu Hu ◽  
Heng Li ◽  
Chuanxiang Sheng
Keyword(s):  
Evanescent Wave ◽  
Single Mode ◽  
Transverse Magnetic ◽  
Ethanol Solution ◽  
Pump Laser ◽  
Fiber Axis ◽  
Lasing Threshold ◽  
Polarization Direction ◽  
Excitation Laser ◽  
Output Laser

Using a fiber of that is 125 μm in diameter in rhodamine 6G ethanol solution, controllable multi- and single-whispering-gallery-mode (WGM) optofluidic lasers based on evanescent-wave-coupled gain are both available. With multi-mode WGM emission, lasing emission with almost pure TM (transverse magnetic) or almost TE (transverse electric) modes can be obtained when the pump laser has an electric field parallel (perpendicular) to the fiber axis, i.e., the polarization direction of output laser is the same as that of the pump laser. On the other hand, when the laser emission is single-mode, the TE output laser always emerges firstly above lasing threshold, then keeps TE mode while the pump laser’s intensity increases with polarization direction perpendicular to the fiber axis; on the contrary, TE emission will dwindle relatively, while the TM emission emerges and dominates the spectra, when the pump laser’s intensity increases with polarization parallel to the fiber axis. Our work proves that controlling the leakage of the evanescent wave from high-Q microcavities is crucial for both modes of lasing emission and its polarization.

scholarly journals A Study of Overripe Seed Byproducts from Sun-Dried Grapes by Dispersive Raman Spectroscopy

Foods ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 483
Author(s):  
Francisco J. Rivero ◽  
Leonardo Ciaccheri ◽  
M. Lourdes González-Miret ◽  
Francisco J. Rodríguez-Pulido ◽  
Andrea A. Mencaglia ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Spectroscopic Data ◽  
Principal Component ◽  
Industrial Applications ◽  
Phenolic Composition ◽  
Grape Seeds ◽  
Detection Scheme ◽  
Sun Drying ◽  
Dried Grapes ◽  
Excitation Laser

Overripe seeds from sun-dried grapes submitted to postharvest dehydration constitute a scarcely investigated class of vinification byproduct with limited reports on their phenolic composition and industrial applications. In this study, Raman spectroscopy was applied to characterize a selection of overripe seed byproducts from different white grapes (cv. Moscatel, cv. Pedro Ximénez and cv. Zalema) submitted to postharvest sun drying. The Raman measurements were taken using a 1064 nm excitation laser in order to mitigate the fluorescent effect and the dispersive detection scheme allowed a compactness of the optical system. Spectroscopic data were processed by a principal component analysis to reduce the dimensionality and partner recognition. The evolution of the Raman spectrum during the overripening process was compared with the phenolic composition of grape seeds, which was determined by rapid resolution liquid chromatography/mass spectrometry (RRLC/MS). A multivariate processing of the spectroscopic data allowed the classification of overripe seeds according to the grape variety and the monitoring of stages of the postharvest sun drying process.

Reconstructing Terrestrial Environments Using Stable Isotopes in Fossil Teeth and Paleosol Carbonates

2012 ◽  
Vol 18 ◽  
pp. 167-194 ◽  
Author(s):  
Benjamin H. Passey
Keyword(s):  
Isotopic Composition ◽  
Soil Temperature ◽  
Carbon Isotopes ◽  
Oxygen Isotopes ◽  
Precipitation Amount ◽  
Radiative Heating ◽  
Mammal Species ◽  
Isotopic Compositions ◽  
Heat Effects ◽  
Oxygen Isotopic

Carbon isotopes in Neogene-age fossil teeth and paleosol carbonates are commonly interpreted in the context of past distributions of C3 and C4 vegetation. These two plant types have very different distributions in relation to climate and ecology, and provide a robust basis for reconstructing terrestrial paleoclimates and paleoenvironments during the Neogene. Carbon isotopes in pre-Neogene fossil teeth are usually interpreted in the context of changes in the δ13C value of atmospheric CO2, and variable climate-dependent carbon-isotope discrimination in C3 plants. Carbon isotopes in pre-Neogene soil carbonates can be used to estimate past levels of atmospheric CO2. Oxygen isotopes in fossil teeth and paleosol carbonates primarily are influenced by the oxygen isotopic compositions of ancient rainfall and surface waters. The oxygen isotopic composition of rainfall is has a complex, but tractable, relationship with climate, and variably relates to temperature, elevation, precipitation amount, and other factors. Mammal species that rely on moisture in dietary plant tissues to satisfy their water requirements (rather than surface drinking water) may have oxygen isotopic compositions that track aridity. Thus, oxygen isotopes of fossil mammals can place broad constraints on paleoaridity. Carbonate clumped isotope thermometry allows for reconstruction of soil temperatures at the time of pedogenic carbonate mineralization. The method is unique because it is the only thermodynamically based isotopic paleothermometer that does not require assumptions about the isotopic composition of the fluid in which the archive mineral formed. Soil temperature reflects a complex interplay of air temperature, solar radiative heating, latent heat effects, soil thermal diffusivity, and seasonal variations of these parameters. Because plants and most animals live in and/or near the soil, soil temperature is an important aspect of terrestrial (paleo)climate.

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