scholarly journals Microstructures and properties of materials under repeated laser irradiation

2007 ◽  
Author(s):  
Robert Averback ◽  
Pascal Bellon
Keyword(s):  
Laser Irradiation ◽  
Properties Of Materials

Metallurgical Effects of Grain Boundary Ledges

1977 ◽  
Vol 35 ◽  
pp. 126-129
Author(s):  
L.E. Murr
Keyword(s):  
Grain Boundary ◽  
Quantitative Data ◽  
Mechanical Treatment ◽  
Unit Length ◽  
Physical And Mechanical Properties ◽  
Direct Observations ◽  
Transmission Electron ◽  
Properties Of Materials ◽  
Thermo Mechanical Treatment ◽  
Ledge Density

Ledges in grain boundaries can be identified by their characteristic contrast features (straight, black-white lines) distinct from those of lattice dislocations, for example1,2 [see Fig. 1(a) and (b)]. Simple contrast rules as pointed out by Murr and Venkatesh2, can be established so that ledges may be recognized with come confidence, and the number of ledges per unit length of grain boundary (referred to as the ledge density, m) measured by direct observations in the transmission electron microscope. Such measurements can then give rise to quantitative data which can be used to provide evidence for the influence of ledges on the physical and mechanical properties of materials.It has been shown that ledge density can be systematically altered in some metals by thermo-mechanical treatment3,4.

A Stable Field Emission Electron Source

1977 ◽  
Vol 35 ◽  
pp. 58-59
Author(s):  
W.R. Bottoms ◽  
G.B. Haydon
Keyword(s):  
Field Emission ◽  
Signal To Noise Ratio ◽  
High Brightness ◽  
Electron Sources ◽  
Brightness Field ◽  
Current Densities ◽  
Properties Of Materials ◽  
Stable Field ◽  
Stable Current ◽  
Careful Design

There is great interest in improving the brightness of electron sources and therefore the ability of electron optical instrumentation to probe the properties of materials. Extensive work by Dr. Crew and others has provided extremely high brightness sources for certain kinds of analytical problems but which pose serious difficulties in other problems. These sources cannot survive in conventional system vacuums. If one wishes to gather information from the other signal channels activated by electron beam bombardment it is necessary to provide sufficient current to allow an acceptable signal-to-noise ratio. It is possible through careful design to provide a high brightness field emission source which has the capability of providing high currents as well as high current densities to a specimen. In this paper we describe an electrode to provide long-lived stable current in field emission sources.The source geometry was based upon the results of extensive computer modeling. The design attempted to maximize the total current available at a specimen.

Chronic Laser Exposure Effects on Rabbit Retina

1972 ◽  
Vol 30 ◽  
pp. 54-55
Author(s):  
Burton B. Silver ◽  
Theodore Lawwill
Keyword(s):  
Laser Irradiation ◽  
Laser Light ◽  
Broad Band ◽  
Argon Laser ◽  
Atropine Sulfate ◽  
Ultrastructural Changes ◽  
Laser Exposure ◽  
Rabbit Retina ◽  
Histological Changes ◽  
Threshold Doses

Dutch-belted 1 to 2.5 kg anesthetized rabbits were exposed to either xenon or argon laser light administered in a broad band, designed to cover large areas of the retina. For laser exposure, the pupil was dilated with atropine sulfate 1% and pheny lephrine 10%. All of the laser generated power was within a band centered at 5145.0 Anstroms. Established threshold for 4 hour exposures to laser irradiation are in the order of 25-35 microwatts/cm2. Animals examined for ultrastructural changes received 4 hour threshold doses. These animals exhibited ERG, opthalmascopic, and histological changes consistent with threshold damage.One month following exposure the rabbits were killed with pentobarbitol. The eyes were immediately enucleated and dissected while bathed in 3% phosphate buffered gluteraldehyde.

Microstructural changes of Aluminum Nitride after laser irradiation and electroless copper deposition

1994 ◽  
Vol 52 ◽  
pp. 636-637
Author(s):  
S. Cao ◽  
A. J. Pedraza ◽  
L. F. Allard
Keyword(s):  
Aluminum Nitride ◽  
Laser Irradiation ◽  
Electroless Deposition ◽  
Thermal Evaporation ◽  
Surface Region ◽  
Near Surface ◽  
Laser Patterning ◽  
Electroless Copper ◽  
Excimer Laser Irradiation ◽  
Laser Effect

Excimer-laser irradiation strongly modifies the near-surface region of aluminum nitride (AIN) substrates. The surface acquires a distinctive metallic appearance and the electrical resistivity of the near-surface region drastically decreases after laser irradiation. These results indicate that Al forms at the surface as a result of the decomposition of the Al (which has been confirmed by XPS). A computer model that incorporates two opposing phenomena, decomposition of the AIN that leaves a metallic Al film on the surface, and thermal evaporation of the Al, demonstrated that saturation of film thickness and, hence, of electrical resistance is reached when the rate of Al evaporation equals the rate of AIN decomposition. In an electroless copper bath, Cu is only deposited in laser-irradiated areas. This laser effect has been designated laser activation for electroless deposition. Laser activation eliminates the need of seeding for nucleating the initial layer of electroless Cu. Thus, AIN metallization can be achieved by laser patterning followed by electroless deposition.

Studies on the mechanism of printing film-coated tablets containing titanium dioxide in the film by using UV laser irradiation

2009 ◽  
Vol 00 (00) ◽  
pp. 090915102728058-8
Author(s):  
Yoshiteru Kato ◽  
Yasuhiko Nakashima ◽  
Naoki Shino ◽  
Koichi Sasaki ◽  
Akihiro Hosokawa ◽  
...  
Keyword(s):  
Titanium Dioxide ◽  
Laser Irradiation ◽  
Uv Laser

Modification of structural and transport properties in epitaxial YBa2CU3Ox films by pulsed laser irradiation

1993 ◽  
Vol 3 (12) ◽  
pp. 2173-2188
Author(s):  
N. G. Chechenin ◽  
A. V. Chernysh ◽  
V. V. Korneev ◽  
E. V. Monakhov ◽  
B. V. Seleznev
Keyword(s):  
Transport Properties ◽  
Laser Irradiation ◽  
Pulsed Laser ◽  
Pulsed Laser Irradiation

PULSED LASER IRRADIATION OF NICKEL THIN FILMS ON SILICON

1983 ◽  
Vol 44 (C5) ◽  
pp. C5-449-C5-454 ◽  
Author(s):  
P. Baeri ◽  
M. G. Grimaldi ◽  
E. Rimini ◽  
G. Celotti
Keyword(s):  
Thin Films ◽  
Laser Irradiation ◽  
Pulsed Laser ◽  
Nickel Thin Films ◽  
Pulsed Laser Irradiation

FUNDAMENTALS OF PULSED LASER IRRADIATION OF SILICON

1983 ◽  
Vol 44 (C5) ◽  
pp. C5-23-C5-36 ◽  
Author(s):  
H. Kurz ◽  
L. A. Lompré ◽  
J. M. Liu
Keyword(s):  
Laser Irradiation ◽  
Pulsed Laser ◽  
Pulsed Laser Irradiation
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