Ionization and dissociative ionization of CO2 by electron impact

1977 ◽  
Vol 55 (21) ◽  
pp. 1889-1897 ◽  
Author(s):  
N. Bussières ◽  
P. Marmet
Keyword(s):  
Kinetic Energy ◽  
Electron Impact ◽  
Signal To Noise Ratio ◽  
Ion Pair ◽  
Pair Formation ◽  
Negative Ion ◽  
High Signal ◽  
Signal To Noise ◽  
Fragment Ions ◽  
Zero Kinetic Energy

Using a very sensitive apparatus with a high signal-to-noise ratio, new structures are observed in the ionization curve of CO2 by electron impact in the first 10 V above the ionization threshold. Neutral and negative ion levels are observed and related to npσu and npπu series converging to Ā, [Formula: see text], and [Formula: see text] levels of CO2+. Data for the fragment ions CO+, O+, and C+ are also presented; it is shown that they can be formed with zero kinetic energy. No ion pair formation can be detected at threshold.

scholarly journals Electroionization study of ethane: structures in the ionization and appearance curves

1987 ◽  
Vol 65 (9) ◽  
pp. 2004-2008 ◽  
Author(s):  
Pierre Plessis ◽  
Paul Marmet
Keyword(s):  
Carbon Atom ◽  
Signal To Noise Ratio ◽  
Negative Ion ◽  
High Signal ◽  
Feshbach Resonances ◽  
Signal To Noise ◽  
Monoenergetic Electron ◽  
Fragment Ions ◽  
Novel Structures ◽  
Very High

Ionization efficiency curves of very high signal-to-noise ratio are presented for ethane and most fragment ions containing at least one carbon atom. These curves, which are produced by monoenergetic electron impact, extend up to 10 eV above the initial onsets. Novel structures are observed in most curves. Certain features appear at the same energy in several of the curves indicating that they belong to a common progenitor, either [Formula: see text] or [Formula: see text], and not directly to the detected ions. These sets of structure are attributed to negative ion states (Feshbach resonances) and/or to Rydberg autoionizing states.

Metastable yield of argon between 23 and 37 eV by electron impact

1979 ◽  
Vol 57 (10) ◽  
pp. 1624-1633 ◽  
Author(s):  
P. Marchand ◽  
J. Cardinal
Keyword(s):  
Electron Impact ◽  
Excited States ◽  
Signal To Noise Ratio ◽  
Negative Ion ◽  
Photon Yield ◽  
Large Signal ◽  
Signal To Noise ◽  
Monoenergetic Electron ◽  
Yield Curves ◽  
Noise Ratio

The metastable yield of argon excited by monoenergetic electron impact has been measured between 23 and 37 eV. Thanks to a large signal-to-noise ratio, many very small structures have been detected superimposed on the metastable continuum and are attributed to Ar− negative-ion states and to highly excited states of Ar. The results are compared with broadband photon yield curves and electroionization curves.

Die Bildung negativer Ionen aus SiCl4 und organischen Siliciumchloriden durch Elektronenstoß

1968 ◽  
Vol 23 (8) ◽  
pp. 1122-1127 ◽  
Author(s):  
K. Jäger ◽  
A. Henglein
Keyword(s):  
Kinetic Energy ◽  
Electron Impact ◽  
Electron Affinity ◽  
Free Electron ◽  
Negative Ions ◽  
Molecular Ions ◽  
Ion Source ◽  
Silicon Compounds ◽  
Fragment Ions ◽  
Zero Kinetic Energy

Appearance potentials and ionization efficiency curves of negative ions formed in SiCl4, CH3SiCl3, (CH3)2SiCl2, (CH3)3) 3SiCl, C2H3SiCl3, and C6H5SiCl3 by electron impact have been measured by using a Fox ion source. Negative molecular ions were observed in SiCl4, C2H3SiCl3 and C6H5SiCl3 besides several fragment ions. The electron affinity of the SiCl3 radical was found to be about equal to the electron affinity of the chlorine atom. The electron affinity of SiCl2 is shown to be higher than 2.5 eV.Dissociative electron capture processes from SF6– have been found in mixtures of SFe and silicon compounds (such as SF6–+SiCl4 ➝ Cl–+SiCl3+SF6). It is concluded that in these processes the electron in SF6– behaves like a free electron of zero kinetic energy. Various reactions of the O–-ion with the silicon compounds have also been observed.

A compact guided-wave EMAT with pulsed electromagnet for ferromagnetic tube inspection

2020 ◽  
Vol 64 (1-4) ◽  
pp. 951-958
Author(s):  
Tianhao Liu ◽  
Yu Jin ◽  
Cuixiang Pei ◽  
Jie Han ◽  
Zhenmao Chen
Keyword(s):  
Power Plants ◽  
Signal To Noise Ratio ◽  
Small Diameter ◽  
Performance Testing ◽  
Guided Wave ◽  
High Signal ◽  
Receiver Coil ◽  
Signal To Noise ◽  
Corrosion Defects

Small-diameter tubes that are widely used in petroleum industries and power plants experience corrosion during long-term services. In this paper, a compact inserted guided-wave EMAT with a pulsed electromagnet is proposed for small-diameter tube inspection. The proposed transducer is noncontact, compact with high signal-to-noise ratio and unattractive to ferromagnetic tubes. The proposed EMAT is designed with coils-only configuration, which consists of a pulsed electromagnet and a meander pulser/receiver coil. Both the numerical simulation and experimental results validate its feasibility on generating and receiving L(0,2) mode guided wave. The parameters for driving the proposed EMAT are optimized by performance testing. Finally, feasibility on quantification evaluation for corrosion defects was verified by experiments.

Narrow-frequency sharp-angular filters using all-dielectric cascaded meta-gratings

Nanophotonics ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 3443-3450 ◽  
Author(s):  
Wei-Nan Liu ◽  
Rui Chen ◽  
Wei-Yi Shi ◽  
Ke-Bo Zeng ◽  
Fu-Li Zhao ◽  
...  
Keyword(s):  
Thin Film ◽  
Signal To Noise Ratio ◽  
Incident Angle ◽  
Design Strategy ◽  
Transmission Peak ◽  
High Signal ◽  
Waveguide Array ◽  
Signal To Noise ◽  
Center Wavelength ◽  
Noise Ratio

AbstractSelective transmission or filtering always responds to either frequency or incident angle, so as hardly to maximize signal-to-noise ratio in communication, detection and sensing. Here, we propose compact meta-filters of narrow-frequency sharp-angular transmission peak along with broad omnidirectional reflection sidebands, in all-dielectric cascaded subwavelength meta-gratings. The inherent collective resonance of waveguide-array modes and thin film approximation of meta-grating are employed as the design strategy. A unity transmission peak, locating at the incident angle of 44.4° and the center wavelength of 1550 nm, is demonstrated in a silicon meta-filter consisting of two-layer silicon rectangular meta-grating. These findings provide possibilities in cascaded meta-gratings spectroscopic design and alternative utilities for high signal-to-noise ratio applications in focus-free spatial filtering and anti-noise systems in telecommunications.

scholarly journals Low-dose, phase-contrast mammography with high signal-to-noise ratio

2016 ◽  
Vol 7 (2) ◽  
pp. 381 ◽  
Author(s):  
Lukas B. Gromann ◽  
Dirk Bequé ◽  
Kai Scherer ◽  
Konstantin Willer ◽  
Lorenz Birnbacher ◽  
...  
Keyword(s):  
Phase Contrast ◽  
Low Dose ◽  
Signal To Noise Ratio ◽  
High Signal ◽  
Signal To Noise ◽  
Noise Ratio

Research on LIFT Technology for 3D Seismic Denoising in Coalfield

2014 ◽  
Vol 556-562 ◽  
pp. 6328-6331
Author(s):  
Su Zhen Shi ◽  
Yi Chen Zhao ◽  
Li Biao Yang ◽  
Yao Tang ◽  
Juan Li
Keyword(s):  
Signal To Noise Ratio ◽  
High Signal ◽  
3D Seismic ◽  
Signal To Noise ◽  
Denoising Method ◽  
Seismic Processing ◽  
Work Area ◽  
Noise Data ◽  
Noise Ratio ◽  
Effective Signal

The LIFT technology has applied in process of denoising to ensure the imaging precision of minor faults and structure in 3D coalfield seismic processing. The paper focused on the denoising process in two study areas where the LIFT technology is used. The separation of signal and noise is done firstly. Then denoising would be done in the noise data. The Data of weak effective signal that is from the noise data could be blended with the original effective signal to reconstruct the denoising data, so the result which has high signal-to-noise ratio and preserved amplitude is acquired. Thus the fact shows that LIFT is an effective denoising method for 3D seismic in coalfield and could be used widely in other work area.

Sign in / Sign up

Export Citation Format

Share Document