A transmission-type triple grating spectrograph for improved laser scattering diagnostics of low-density plasmas used in chemical analysis

2020 ◽  
Vol 35 (9) ◽  
pp. 1932-1946
Author(s):  
Kevin Finch ◽  
Aldo Hernandez ◽  
Yue She ◽  
Songyue Shi ◽  
Gerardo Gamez
Keyword(s):  
Detection Limit ◽  
Chemical Analysis ◽  
Electron Density ◽  
Measurement Time ◽  
Low Density ◽  
Laser Scattering ◽  
Plasma Species

An improved transmission-type triple grating spectrograph permits 2D mapping of plasma species via laser scattering closer to surfaces, at faster measurement time, and the lowest electron density detection limit reported.

scholarly journals Барьерный разряд в гелии при средних давлениях. Спектроскопия послесвечения

2019 ◽  
Vol 126 (3) ◽  
pp. 247 ◽  
Author(s):  
В.А. Иванов
Keyword(s):  
Dielectric Barrier Discharge ◽  
Electron Density ◽  
Barrier Discharge ◽  
Pulse Discharge ◽  
Cylindrical Tube ◽  
Plasma Electron ◽  
Low Density ◽  
Dielectric Barrier ◽  
Plasma Electron Density

AbstractThe decaying plasma that is produced by the dielectric barrier discharge (DBD) in helium across a cylindrical tube at a pressure of helium 1–40 Тorr has been spectroscopically investigated. The radical difference between the nature of the barrier discharge afterglow and longitudinal pulse discharge afterglow at the same plasma electron density has been demonstrated. It has been shown that this effect is due to the abnormally low density of metastable He(2^1 S _0, ^3 S _1) atoms in the plasma that is produced by DBD. In such an experiment, it is possible to observe a purely recombination afterglow that is free of processes involving metastable atoms, which is fundamentally important for solving the problem of helium afterglow.

Development of a Standard Method – Analysis of Compounds Causing Tastes and Odors in Drinking Water

1999 ◽  
Vol 40 (6) ◽  
pp. 279-285 ◽  
Author(s):  
Connie C. Young ◽  
I. H. (Mel) Suffet
Keyword(s):  
Drinking Water ◽  
Detection Limit ◽  
Chemical Analysis ◽  
Standard Method ◽  
Gc Analysis ◽  
Hexenyl Acetate ◽  
Off Flavors ◽  
Method Analysis

A standard method for analyzing 22 off-flavors in drinking water was developed. It includes chemical analysis - CLSA and SDE coupled with GC-MS, and sensory techniques - FPA and sensory GC analysis. Trans, trans-2,4-Heptadienal, a newly found fishy causing compound, was studied for its detection limit and OTC. Two grassy causing compounds, cis-3-hexen-1-ol and cis-3-hexenyl acetate, were also evaluated.

scholarly journals Using N-doped Carbon Dots Prepared Rapidly by Microwave Digestion as Nanoprobes and Nanocatalysts for Fluorescence Determination of Ultratrace Isocarbophos with Label-Free Aptamers

Nanomaterials ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 223 ◽  
Author(s):  
Xin Li ◽  
Xin Jiang ◽  
Qingye Liu ◽  
Aihui Liang ◽  
Zhiliang Jiang
Keyword(s):  
Catalytic Activity ◽  
Detection Limit ◽  
Fluorescent Probe ◽  
Carbon Dots ◽  
Rapid Determination ◽  
Microwave Digestion ◽  
Label Free ◽  
Laser Scattering ◽  
Doped Carbon Dots

The strongly fluorescent and highly catalytic N-doped carbon dots (CDN) were rapidly prepared by a microwave irradiation procedure and were characterized by electron microscopy (EM), laser scattering, infrared spectroscopy (IR), and by their fluorescence spectrum. It was found that the CDN had a strong catalytic effect on the fluorescence reaction of 3,3′,5,5′-tetramethylbenzidine hydroxide ((TMB)–H2O2) which produced the oxidation product of TMB (TMBOX) with strong fluorescence at 406 nm. The aptamer (Apt) was adsorbed on the CDN surfaces which weakened the fluorescence intensity due to the inhibition of catalytic activity. When the target molecule isocarbophos (IPS) was added, it reacted with the Apt to form a stable conjugate and free CDN which restored the catalytic activity to enhance the fluorescence. Using TMBOX as a fluorescent probe, a highly sensitive nanocatalytic method for determination of 0.025–1.5 μg/L IPS was established with a detection limit of 0.015 μg/L. Coupling the CDN fluorescent probe with the Apt–IPS reaction, a new CD fluorescence method was established for the simple and rapid determination of 0.25–1.5 μg/L IPS with a detection limit of 0.11 μg/L.

scholarly journals Symbiotic Stars and Planetary Nebulae in the λ5007/Hβ vs. λ4363/Hγ Diagnostic Diagram

2009 ◽  
Vol 5 (S262) ◽  
pp. 307-308
Author(s):  
N. O. Baella
Keyword(s):  
Electron Density ◽  
Planetary Nebulae ◽  
Low Density ◽  
Symbiotic Star ◽  
Symbiotic Stars ◽  
Diagnostic Diagram ◽  
Flux Measurements ◽  
Electron Density And Temperature

AbstractIn this work the location of a sample of 174 flux measurements (planetary nebulae, S, D, D'-type Symbiotic Star (SS) and six peculiar objects) on the λ5007/Hβ vs. λ4363/Hγ diagnostic diagram are compared, in order to investigate possible differences in electron density and temperature among them. Helium abundances, electron density and temperature were obtained for five D'-type SS and HD149427 (PC 11). In order to calculate them, expressions normally used for objects with low density were modified, in such a way that they can be used in objects with higher densities.

scholarly journals Estimate of pre-thermal quench non-thermal electron density profile during Ar pellet shutdowns of low-density target plasmas in DIII-D

2021 ◽  
Vol 28 (7) ◽  
pp. 072501
Author(s):  
E. M. Hollmann ◽  
M. Austin ◽  
I. Bykov ◽  
N. W. Eidietis ◽  
O. Embreus ◽  
...  
Keyword(s):  
Electron Density ◽  
Density Profile ◽  
Electron Density Profile ◽  
Low Density ◽  
Thermal Electron

Spectrochemical Analysis of Liquids Using the Laser Spark

1984 ◽  
Vol 38 (5) ◽  
pp. 721-729 ◽  
Author(s):  
David A. Cremers ◽  
Leon J. Radziemski ◽  
Thomas R. Loree
Keyword(s):  
Standard Deviation ◽  
Detection Limit ◽  
Laser Pulse ◽  
Aqueous Solutions ◽  
Electron Density ◽  
Relative Standard Deviation ◽  
Sample Analysis ◽  
Relative Standard ◽  
Laser Spark ◽  
Simple Molecules

A laser-generated spark was used to analyze liquids spectroscopically for elemental constituents The spark was produced directly in liquids by a focused laser pulse of 15 ns duration and an energy of about 45 mJ/pulse The size, temperature, and electron density of the spark are reported Emissions from once-ionized and neutral atoms and simple molecules were observed Limits of detection for Li, Na, K, Rb, Cs, Be, Mg, Ca, B, and Al in aqueous solutions were established with the use of a 10 Hz repetitive single spark (RSS) Most of these elements were only detectable at levels above 1 µg/mL, although the detection limit for Li was 0006 µg/mL The relative standard deviation for replicate sample analysis was 4–8% The detectability of some species was enhanced with the use of a 10 Hz repetitive spark pair (RSP): a pair of sparks separated in time by about 18 µs The detection limits for B/H2O with the RSP and the RSS were 80 and 1200 µg/mL, respectively Species were also detected in organic solvents and in flowing samples The laser spark method of liquid analysis would be useful in situations requiring noninvasive monitoring of species at high or moderate concentrations

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