scholarly journals The Study of Complex (Ti, Zr, Cs) Nanopowder Influencing the Effective Ionization Potential of Arc Discharge When Mma Welding

2016 ◽  
Vol 142 ◽  
pp. 012018
Author(s):  
S B Sapozhkov ◽  
E M Burakova
Keyword(s):  
Ionization Potential ◽  
Arc Discharge ◽  
Mma Welding ◽  
Effective Ionization

scholarly journals Recent studies of the spectrum of V1016 Cygni

1982 ◽  
Vol 70 ◽  
pp. 161-164
Author(s):  
G. Muratorio ◽  
M. Friedjung
Keyword(s):  
Radial Velocity ◽  
Ionization Potential ◽  
Radial Velocities ◽  
Emission Lines ◽  
Computer Programme ◽  
Half Maximum ◽  
The Mean ◽  
Effective Ionization

Two coudé spectra of V1016 Cyg taken on June 24 and 27, 1979 were reduced, using a computer programme developed in Marseille. Radial velocities and full widths at half maximum were measured for the emission lines, and are summarized in the following table were VR is the mean radial velocity in km s-1, DV the velocity corresponding to the mean FWHM and Xi the effective ionization potential for the ion.

Teoretical Tools for Practical ALCHEMI

2001 ◽  
Vol 7 (S2) ◽  
pp. 348-349
Author(s):  
L. J. Allen ◽  
M. P. Oxley
Keyword(s):  
Ionization Potential ◽  
Cross Sections ◽  
First Principles Calculations ◽  
Ionization Cross ◽  
Precise Shape ◽  
Atomic Scattering ◽  
Computationally Intensive ◽  
Ionization Cross Sections ◽  
Shell Ionization ◽  
Effective Ionization

Precisely known atomic scattering factors are essential for accurate atom location by channelling enhanced microanalysis (ALCHEMI) based on inner-shell ionization.1 For ALCHEMI using energy dispersive x-ray analysis (EDX), first principles calculations of ionization cross sections, realistically modeling the “delocalization” of the ionization interaction, give excellent agreement with experiment.2 Such calculations are complex and computationally intensive. Hence, simple analytic forms are often assumed to describe the ionization potential. However such analytic forms require prior knowledge of the “delocalization” of the effective ionization interaction. Such an approach assumes that the precise shape of the ionization potential is not important but that at least the half width at half maximum (HWHM) should be accurately estimated, for example using estimates of the HWHM from root-mean-square impact parameters for ionization. However this is generally not a good approximation3 and we have provided more realistic estimates (Fig. 1).

The First Measured Stark Width and Shift of the 402.6186 nm He I Line

2005 ◽  
Vol 60 (4) ◽  
pp. 282-284 ◽  
Author(s):  
Stevan Djeniže ◽  
Aleksandar Srećković ◽  
Srdjan Bukvić
Keyword(s):  
Spectral Line ◽  
Electron Density ◽  
Arc Discharge ◽  
Energy Levels ◽  
Pulsed Arc Discharge ◽  
Experimental Values ◽  
Pulsed Arc ◽  
Theoretical Results ◽  
Stark Width ◽  
Effective Ionization

Abstract Stark width (W) and shift (d) of the neutral helium (He I) 402.6186 nm spectral line in the high lying 2p-5d transition have been measured in the optically thin helium plasma created in a linear, low-pressure, pulsed arc discharge at a 52,000 K electron temperature and 1.3 · 1023 m−3 electron density. Obtained data are the first experimental values of the Stark width and shift related to the mentioned He I spectral line. Direct comparison with theoretical results is not possible due to the fact that available data are calculated for considerably lower electron densities. We found that at 1023 m−3 electron density the lowering of the effective ionization energy has influence on the number and contribution of the perturbing energy levels, especially in the case of the high lying parent energy level of the particular transition. This effect generates lower Stark widths in the high lying He I transitions than the existing theoretical approximations provide. We have found negative Stark shift.

An Attack on the Contamination Problem in the Electron Microscope

1967 ◽  
Vol 25 ◽  
pp. 368-368
Author(s):  
J. J. Kelsch ◽  
A. Holtz
Keyword(s):  
Electron Microscope ◽  
Pressure Gradient ◽  
Ionization Potential ◽  
Simple Solution ◽  
Specimen Surface ◽  
Contamination Rate ◽  
Local Pressure ◽  
High Ionization ◽  
Hydrocarbon Molecules ◽  
Contamination Problem

A simple solution to the serious problem of specimen contamination in the electron microscope is presented. This is accomplished by the introduction of clean helium into the vacuum exactly at the specimen position. The local pressure gradient thus established inhibits the migration of hydrocarbon molecules to the specimen surface. The high ionization potential of He permits the use of relatively large volumes of the gas, without interfering with gun stability. The contamination rate is reduced on metal samples by a factor of 10.

Preparation and characterization of thin films of carbon nitride

1995 ◽  
Vol 53 ◽  
pp. 104-105
Author(s):  
L. Wan ◽  
R. F. Egerton
Keyword(s):  
Carbon Nitride ◽  
Arc Discharge ◽  
Ion Beam ◽  
Chemical Vapor ◽  
Reactive Sputtering ◽  
Vacuum Arc ◽  
Specimen Preparation ◽  
Bonding Structure ◽  
Electron Energy Loss

INTRODUCTION Recently, a new compound carbon nitride (CNx) has captured the attention of materials scientists, resulting from the prediction of a metastable crystal structure β-C3N4. Calculations showed that the mechanical properties of β-C3N4 are close to those of diamond. Various methods, including high pressure synthesis, ion beam deposition, chemical vapor deposition, plasma enhanced evaporation, and reactive sputtering, have been used in an attempt to make this compound. In this paper, we present the results of electron energy loss spectroscopy (EELS) analysis of composition and bonding structure of CNX films deposited by two different methods.SPECIMEN PREPARATION Specimens were prepared by arc-discharge evaporation and reactive sputtering. The apparatus for evaporation is similar to the traditional setup of vacuum arc-discharge evaporation, but working in a 0.05 torr ambient of nitrogen or ammonia. A bias was applied between the carbon source and the substrate in order to generate more ions and electrons and change their energy. During deposition, this bias causes a secondary discharge between the source and the substrate.

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