Mass spectrometry of positive ions in capacitively coupled low pressure RF discharges in oxygen with water impurities

This paper presents an investigation of argon capacitively coupled plasma at low pressure. A two-dimensional, time-dependent fluid model is used to describe the production, transport, and destruction of electrons and positive ions. The model is solved for a GEC(gaseous electronics conference) Cell reactor type (with 4cm diameter and 2.5cm interelectrode distance) operating at frequency 13.56MHz, pressure 1Torr and applied voltage 1000V, in pure argon. Two-dimensional distributions are presented in the stationary state, including electron temperature and species density i.e. electron, ion and metastable atom. The electric field and electric potential at different phases in one RF cycle is also studied.

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Effect of Low-Pressure Plasma Treatment Parameters on Wrinkle Features

Materials ◽

10.3390/ma13173852 ◽

2020 ◽

Vol 13 (17) ◽

pp. 3852

Author(s):

Bongjun Gu ◽

Dongwook Ko ◽

Sungjin Jo ◽

Dong Choon Hyun ◽

Hyeon-Ju Oh ◽

...

Keyword(s):

Power Flow ◽

Treatment Time ◽

Argon Plasma ◽

Negative Ions ◽

Low Pressure ◽

Nitrogen Plasma ◽

Pressure Plasma ◽

Positive Ions ◽

Low Pressure Plasma ◽

Optical Adhesive

Wrinkles attract significant attention due to their ability to enhance the mechanical and optical characteristics of various optoelectronic devices. We report the effect of the plasma gas type, power, flow rate, and treatment time on the wrinkle features. When an optical adhesive was treated using a low-pressure plasma of oxygen, argon, and nitrogen, the oxygen and argon plasma generated wrinkles with the lowest and highest wavelengths, respectively. The increase in the power of the nitrogen and oxygen plasma increased the wavelengths and heights of the wrinkles; however, the increase in the power of the argon plasma increased the wavelengths and decreased the heights of the wrinkles. Argon molecules are heavier and smaller than nitrogen and oxygen molecules that have similar weights and sizes; moreover, the argon plasma comprises positive ions while the oxygen and nitrogen plasma comprise negative ions. This resulted in differences in the wrinkle features. It was concluded that a combination of different plasma gases could achieve exclusive control over either the wavelength or the height and allow a thorough analysis of the correlation between the wrinkle features and the characteristics of the electronic devices.

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Metabolomic and Genetic Analysis of Biomarkers for Peroxisome Proliferator-Activated Receptor α Expression and Activation

Molecular Endocrinology ◽

10.1210/me.2007-0150 ◽

2007 ◽

Vol 21 (9) ◽

pp. 2136-2151 ◽

Cited By ~ 55

Author(s):

Yueying Zhen ◽

Kristopher W. Krausz ◽

Chi Chen ◽

Jeffrey R. Idle ◽

Frank J. Gonzalez

Keyword(s):

Mass Spectrometry ◽

Ultra Performance Liquid Chromatography ◽

Urinary Biomarkers ◽

Xanthurenic Acid ◽

Peroxisome Proliferator ◽

Peroxisome Proliferator Activated Receptor ◽

Flight Mass Spectrometry ◽

Positive Ions ◽

Components Analysis ◽

Definition Of

Abstract Peroxisome proliferator-activated receptor α (PPARα) is a nuclear receptor with manifold effects on intermediary metabolism. To define a set of urinary biomarkers that could be used to determine the efficacy of PPARα agonists, a metabolomic investigation was undertaken in wild-type and Pparα-null mice fed for 2 wk either a regular diet or a diet containing the PPARα ligand Wy-14,643 ([4-chloro-6-(2,3-xylidino)-2-pyrimidinylthio] acetic acid), and their urine was analyzed by ultra-performance liquid chromatography coupled with time-of-flight mass spectrometry. Principal components analysis of 6393 accurate mass positive ions revealed clustering as a single phenotype of the treated and untreated Pparα (−/−) mice plus two additional discrete phenotypes for the treated and untreated Pparα (+/+) mice. Biomarkers of PPARα activation were identified from their accurate masses and confirmed by tandem mass spectrometry of authentic compounds. Biomarkers were quantitated from raw chromatographic data using appropriate calibration curves. PPARα urinary biomarkers highly statistically significantly elevated by Wy-14,643 treatment included 11β-hydroxy-3,20-dioxopregn-4-en-21-oic acid (>3700-fold), 11β,20-dihydroxy-3-oxopregn-4-en-21-oic acid (50-fold), nicotinamide (>2-fold), nicotinamide 1-oxide (5-fold), 1-methylnicotinamide (1.5-fold), hippuric acid (2-fold), and 2,8-dihydroxyquinoline-β-d-glucuronide (3-fold). PPARα urinary biomarkers highly statistically significantly attenuated by Wy-14,643 treatment included xanthurenic acid (1.3-fold), hexanoylglycine (20-fold), phenylpropionylglycine (4-fold), and cinnamoylglycine (9-fold). These biomarkers arise from PPARα effects on tryptophan, corticosterone, and fatty acid metabolism and on glucuronidation. This study underscores the power of mass spectrometry-based metabolomics combined with genetically modified mice in the definition of monogenic metabolic phenotypes.

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Photoionization mass spectrometry and modeling study of a low-pressure premixed flame of ethyl pentanoate (ethyl valerate)

Proceedings of the Combustion Institute ◽

10.1016/j.proci.2016.07.038 ◽

2017 ◽

Vol 36 (1) ◽

pp. 1185-1192 ◽

Cited By ~ 3

Author(s):

D.A. Knyazkov ◽

I.E. Gerasimov ◽

N. Hansen ◽

A.G. Shmakov ◽

O.P. Korobeinichev

Keyword(s):

Mass Spectrometry ◽

Low Pressure ◽

Premixed Flame ◽

Photoionization Mass Spectrometry ◽

Modeling Study

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Estimation of Ion Impact Energies and Electrode Self-Bias Voltage in Capacitive RF Discharges

MRS Proceedings ◽

10.1557/proc-98-35 ◽

1987 ◽

Vol 98 ◽

Cited By ~ 2

Author(s):

S. E. Savas

Keyword(s):

Bias Voltage ◽

Capacitively Coupled ◽

Ion Flow ◽

Rf Discharges ◽

Self Bias ◽

Ion Energies ◽

Bias Ratio ◽

Ionization Model ◽

Ion Impact ◽

Impact Energies

ABSTRACTThe dependences of the electrode self-bias voltage and the ratio of ion energies on electrode area ratio are calculated for a model of capacitively coupled rf discharges. It is assumed that concentric spherical elecrodes with fluid-like radial ion flow adequately models the ion motion, that sheath impedances are dominant, and that ionization processes in the glow are due to ohmically heated electrons. Results show that the ratio of ion energies impacting the smaller electrode to those on the larger depends on the ratio of electrode areas in a more complex manner than a power law.The reason for this is that sheath impedances are more resistive or capacitive at different times in the rf cycle. The self-bias ratio is found to depend relatively little on the ionization model or the pressure but differs substantially from the “power law” result. The agreement of measurements with the model is fairly good.

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