157 nm fluorine laser ablation of wooden surfaces as an improved preparation technique for microscopy

2005 ◽  
Vol 2 (1) ◽  
pp. 16-20 ◽  
Author(s):  
M Kopp ◽  
E Roddewig ◽  
H Günther ◽  
G Ohms ◽  
M Leck ◽  
...  
Keyword(s):  
Laser Ablation ◽  
Preparation Technique

Congruent Evaporation and Epitaxy in Thin Film Laser Ablation Deposition (Lad) of Rare Earth Transition Metal Elements and Compounds

1990 ◽  
Vol 191 ◽  
Author(s):  
J. P. Gavigan ◽  
D. Givord ◽  
A. Lienard ◽  
O. F. K. Mcgrath ◽  
J. P. Rebouillat ◽  
...  
Keyword(s):  
Thin Film ◽  
Rare Earth ◽  
Laser Ablation ◽  
Transition Metal ◽  
High Energy ◽  
Preparation Technique ◽  
Picosecond Pulses ◽  
Preparation Conditions ◽  
Thin Film Preparation ◽  
Diffraction Patterns

ABSTRACTLaser ablation deposition (LAD) is a versatile thin film preparation technique which has been slowly developing for a number of years, and is currently receiving a lot of attention as demand increasingly exploits its advantages over other established techniques. Apart from its simplicity, one of its main advantages is the possibility of congruently evaporating any solid compound target, be it metal or insulator, due to the extremely high energy and instantaneous power densities attainable with pulsed lasers (up to 50 Jcm−2 and 1012 Wcm−2 for picosecond pulses). In this paper, we report on tests for both congruent evaporation in LAD of a number of rare earth - transition metal intermetallic compounds including Nd2 Fe1 3 B, Yzn0.7, Yni3, Y2 Fe15 and Yni5 for different preparation conditions (using a Nd:YAG laser λ = 1064, 532, 355 nm, τ = 35 ps and 20 ns) and on the epitaxial growth of Yni5 and W on monocrystalline sapphire substrates. Optical and electron microscopy were used to examine film morphology while congruent evaporation was confirmed using x-ray microprobe analysis. In-situ RHEED revealed good epitaxy of the films deposited on sapphire, with the hexagonal diffraction patterns obtained for YNis being identical to those of an YNi 5 reference single crystal.

Laser ablation in liquids: an efficient sample preparation technique in ICP elemental analysis of art materials

2007 ◽  
Author(s):  
E. V. Klyachkovskaya ◽  
N. M. Kozhukh ◽  
E. V. Muravitskaya ◽  
V. A. Rosantsev ◽  
M. V. Belkov ◽  
...  
Keyword(s):  
Laser Ablation ◽  
Sample Preparation ◽  
Elemental Analysis ◽  
Preparation Technique ◽  
Sample Preparation Technique ◽  
Laser Ablation In Liquids

Direct Determination of Copper in Solids by Direct Current Argon Plasma Emission Spectrometry with Sample Introduction Using Laser Ablation

1987 ◽  
Vol 41 (1) ◽  
pp. 141-148 ◽  
Author(s):  
Peter G. Mitchell ◽  
Joseph Sneddon ◽  
Leon J. Radziemski
Keyword(s):  
Laser Ablation ◽  
Direct Current ◽  
Argon Plasma ◽  
Sample Introduction ◽  
Emission Spectrometry ◽  
Single Shot ◽  
Plasma Emission ◽  
Preparation Technique ◽  
Determination Of Copper

A direct-current argon plasma emission spectrometric system with sample introduction using laser ablation has been developed and evaluated for the determination of copper in pelletized powder and solid samples. The use of a low-energy and high-repetition-rate Nd: YAG laser gave a nearly steady-state signal that could be integrated over a relatively long time period of 30 s. This allowed a larger portion of the sample to be probed, and high % RSD—often obtained with single shot laser ablation because of sample inhomogeneities—reduced to 2–6%. The emission intensity was dependent on sample preparation technique, particle size, laser pulse rate, and copper anion. The system was used to directly determine copper in pelletized ore samples with 2–6% RSD, a detection limit of 20 μg g−1, and acceptable accuracy, once the factors described above were controlled.

Contrast from epitaxially sandwiched macromolecules

1978 ◽  
Vol 36 (2) ◽  
pp. 226-227
Author(s):  
M. Talianker ◽  
D.G. Brandon
Keyword(s):  
Gold Film ◽  
Lattice Defect ◽  
Gold Foil ◽  
Specimen Preparation ◽  
Preparation Technique ◽  
Resolution Limit ◽  
Transmission Electron ◽  
Crystal Lattice Defect ◽  
Void Effect ◽  
Lattice Resolution

A new specimen preparation technique for visualizing macromolecules by conventional transmission electron microscopy has been developed. In this technique the biopolymer-molecule is embedded in a thin monocrystalline gold foil. Such embedding can be performed in the following way: the biopolymer is deposited on an epitaxially-grown thin single-crystal gold film. The molecule is then occluded by further epitaxial growth. In such an epitaxial sandwich an occluded molecule is expected to behave as a crystal-lattice defect and give rise to contrast in the electron microscope.The resolution of the method should be limited only by the precision with which the epitaxially grown gold reflects the details of the molecular structure and, in favorable cases, can approach the lattice resolution limit.In order to estimate the strength of the contrast due to the void-effect arising from occlusion of the DNA-molecule in a gold crystal some calculations were performed.

The ionic strength dependence of chromatin folding

1978 ◽  
Vol 36 (2) ◽  
pp. 220-221
Author(s):  
F. Thoma ◽  
TH. Koller
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Ionic Strength ◽  
Specimen Preparation ◽  
Preparation Technique ◽  
Carbon Supports ◽  
Ionic Strength Dependence ◽  
Chromatin Folding ◽  
Strength Dependence ◽  
Preparation Techniques

Under a variety of electron microscope specimen preparation techniques different forms of chromatin appearance can be distinguished: beads-on-a-string, a 100 Å nucleofilament, a 250 Å fiber and a compact 300 to 500 Å fiber.Using a standardized specimen preparation technique we wanted to find out whether there is any relation between these different forms of chromatin or not. We show that with increasing ionic strength a chromatin fiber consisting of a row of nucleo- somes progressively folds up into a solenoid-like structure with a diameter of about 300 Å.For the preparation of chromatin for electron microscopy the avoidance of stretching artifacts during adsorption to the carbon supports is of utmost importance. The samples are fixed with 0.1% glutaraldehyde at 4°C for at least 12 hrs. The material was usually examined between 24 and 48 hrs after the onset of fixation.

SEM evaluation of the TEM cold-stage double-film specimen

1984 ◽  
Vol 42 ◽  
pp. 272-273
Author(s):  
Jayesh Bellare
Keyword(s):  
Spatial Distribution ◽  
Sample Preparation ◽  
Sample Thickness ◽  
Specimen Preparation ◽  
Preparation Technique ◽  
Liquid Sample ◽  
Thin Specimen ◽  
Sample Preparation Technique ◽  
Cold Stage ◽  
Film Specimen

Seeing is believing, but only after the sample preparation technique has received a systematic study and a full record is made of the treatment the sample gets.For microstructured liquids and suspensions, fast-freeze thermal fixation and cold-stage microscopy is perhaps the least artifact-laden technique. In the double-film specimen preparation technique, a layer of liquid sample is trapped between 100- and 400-mesh polymer (polyimide, PI) coated grids. Blotting against filter paper drains excess liquid and provides a thin specimen, which is fast-frozen by plunging into liquid nitrogen. This frozen sandwich (Fig. 1) is mounted in a cooling holder and viewed in TEM.Though extremely promising for visualization of liquid microstructures, this double-film technique suffers from a) ireproducibility and nonuniformity of sample thickness, b) low yield of imageable grid squares and c) nonuniform spatial distribution of particulates, which results in fewer being imaged.

Observations on the growth of YBa2Cu3O7-δ thin films on MgO by pulsed-laser ablation

1991 ◽  
Vol 49 ◽  
pp. 1068-1069
Author(s):  
M. Grant Norton ◽  
C. Barry Carter
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Laser Ablation ◽  
Substrate Surface ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
Thin Film Deposition ◽  
Film Deposition ◽  
Laser Ablation Process ◽  
Deposition Parameters

Pulsed-laser ablation has been widely used to produce high-quality thin films of YBa2Cu3O7-δ on a range of substrate materials. The nonequilibrium nature of the process allows congruent deposition of oxides with complex stoichiometrics. In the high power density regime produced by the UV excimer lasers the ablated species includes a mixture of neutral atoms, molecules and ions. All these species play an important role in thin-film deposition. However, changes in the deposition parameters have been shown to affect the microstructure of thin YBa2Cu3O7-δ films. The formation of metastable configurations is possible because at the low substrate temperatures used, only shortrange rearrangement on the substrate surface can occur. The parameters associated directly with the laser ablation process, those determining the nature of the process, e g. thermal or nonthermal volatilization, have been classified as ‘primary parameters'. Other parameters may also affect the microstructure of the thin film. In this paper, the effects of these ‘secondary parameters' on the microstructure of YBa2Cu3O7-δ films will be discussed. Examples of 'secondary parameters' include the substrate temperature and the oxygen partial pressure during deposition.

Ultramicrotomy as a Technique for Materials Specimen Preparation

1990 ◽  
Vol 48 (2) ◽  
pp. 428-429
Author(s):  
S.R. Glanvill
Keyword(s):  
Materials Science ◽  
Structural Information ◽  
Specimen Preparation ◽  
Preparation Technique ◽  
Cross Sectional ◽  
Surfaces And Interfaces ◽  
Beam Analysis ◽  
Flat Embedding ◽  
20 Nm ◽  
Sectional Analysis

This paper summarizes the application of ultramicrotomy as a specimen preparation technique for some of the Materials Science applications encountered over the past two years. Specimens 20 nm thick by hundreds of μm lateral dimension are readily prepared for electron beam analysis. Materials examined include metals, plastics, ceramics, superconductors, glassy carbons and semiconductors. We have obtain chemical and structural information from these materials using HRTEM, CBED, EDX and EELS analysis. This technique has enabled cross-sectional analysis of surfaces and interfaces of engineering materials and solid state electronic devices, as well as interdiffusion studies across adjacent layers.Samples are embedded in flat embedding moulds with Epon 812 epoxy resin / Methyl Nadic Anhydride mixture, using DY064 accelerator to promote the reaction. The embedded material is vacuum processed to remove trapped air bubbles, thereby improving the strength and sectioning qualities of the cured block. The resin mixture is cured at 60 °C for a period of 80 hr and left to equilibrate at room temperature.

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