Microspectral Analysis Research Articles

Formation of Low-Temperature Seals and Coatings Based on Low-Melting Lead-Tellurite Glasses

The process of formation of seals and coatings based on low-melting lead-tellurite glasses is studied. The results of a microspectral analysis of the element distribution in glass - aluminum and glass - quartz seals are specified.

Optimisation of the cutting edge roundness and its manufacturing procedures of cemented carbide inserts, to improve their milling performance after a PVD coating deposition

The fatigue and wear behaviour of PVD coatings on cemented carbide inserts with various cutting edge radii are investigated experimentally and analytically in milling. The inserts with cutting edge radii from 8 up to 35 μm were manufactured by honing and micro-blasting. The tool wear progress was depicted through Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray (EDX) microspectral analysis. The Finite Elements Method (FEM) simulation of the contact between the tool and the workpiece highlights the effect of the cutting edge radius on the first coating fracture and the further wear development. The wear behaviour of the cutting edge radii manufactured by honing, in comparison to the corresponding ones by means of micro-blasting, is significantly enhanced, whereas the cutting edge radius increasing can lead to a higher tool life.

Effect of the Cutting Edge Radius and its Manufacturing Procedure, on the Milling Performance of PVD Coated Cemented Carbide Inserts

The fatigue and wear behaviour of PVD coatings on cemented carbide inserts with various cutting edge radii are investigated experimentally and analytically in milling. The inserts with cutting edge radii from 8 up to 35 μm were manufactured by honing and micro-blasting. The tool wear progress was depicted through Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray (EDX) microspectral analysis. The Finite Elements Method (FEM) simulation of the contact between the tool and the workpiece highlights the effect of the cutting edge radius on the first coating fracture and the further wear development. The wear behaviour of the cutting edge radii manufactured by honing, in comparison to the corresponding ones by means of micro-blasting, is significantly enhanced, whereas the cutting edge radius increasing can lead to a higher tool life.

A laser-erosion collector for microspectral analysis of solid inorganic materials

To carry out a microspectral analysis of solid inorganic materials with preliminary laser sampling, we suggest a collector consisting of two thin graphite semidisks, which in sampling are installed on the specimen surface with a certain gap for passage of laser radiation. The specific features and analytical application of the collector are considered.

Modelling the interaction between laser and target material in laser microspectral analysis

The interaction between laser radiation and target material plays an important role in understanding and controlling any material processing technique involving lasers. In this paper, a two-dimensional time-dependent model, based on heat transfer and energy conservation theory, has been developed to simulate the transient material behaviour in laser microspectral analysis (LMA). The spatial and temporal profile of the laser beam and the temperature dependent properties of the material, such as absorptivity, heat capacity and thermal conductivity, are considered. Finally, the experimental and computational results are compared and the interaction between the laser radiation and workpiece are discussed.

Development of a cell-free system to study the membrane assembly of photosynthetic proteins of Rhodobacter capsulatus.

A cell-free translation system from the facultatively photoheterotrophic bacterium Rhodobacter capsulatus is described. Synthesis of two proteins of the bacterium's photosynthetic apparatus (light-harvesting complex B870 alpha and beta) was performed by SP6 polymerase transcription of the subcloned genes, isolation of the mRNA and translation in vitro using a cell-free extract of R. capsulatus cells. The integration of these proteins in vitro into added intracytoplasmic membrane vesicles (ICM) is demonstrated. Without addition of ICM approximately 70% of the synthesized B870 proteins were soluble. If, however, ICM were present during synthesis, the majority of the soluble protein was found to associate with the membranes. The membrane-associated polypeptides could be solubilized only by detergent treatment but could not be extracted by treatment at alkaline pH (Na2CO3), suggesting that the proteins had been firmly inserted into the lipid bilayer. Moreover, the B870 alpha and beta proteins that integrated in vitro into ICM were also found to associate with pigment ligands and to assemble into a native reaction center/B870 complex. The native conformation of this complex isolated from ICM by Triton fractionation was demonstrated by microspectral analysis of the bound pigments.

Application of laser microspectral analysis for the determination of activating additives in alkali-halide single crystals

The authors applied microspectral analysis with the direct excitation of the spectra by laser radiation to the determination of the content of activators -- thallium and sodium -- in single crystals of sodium and cesium iodide. They focused radiation from a neodymium - activated yttrium aluminum garnet laser (LTIPCh-7 apparatus), operating in the pulsed Q-switch mode, on the surface of a single crystal in the form of a light spot with a diameter of 25-30 um. The plasma flame obtained from the evaporating substance was photographed with an ISP-30 spectrograph. The authors state that the procedures of laser spectral analysis developed here permit studying the distribution of the activator and selecting the working region of the crystal without destroying it; they are also rapid, and they economize on expensive materials.

Decreasing the laser radiation absorption in the plasma plume and improving the sensitivity in quantitative laser microspectral analysis

Results from investigations along two lines are presented: a study of the screening effect of the laser induced microplasma and the possibility of improving the limit of detection, the concentration sensitivity and reproducibility in laser microspectral analysis. Cross-sectional probing of the laser induced plasma plume is achieved with a deviated part of the laser beam, evaporating the substance. The absorbance of the plasma generated by different substances at different heights above the sample surface for a fixed laser energy has been studied as well. It has been established that laser energy absorption in the plasma plume decreases when the sample is inclined with respect to the laser radiation direction. This is due to the shorter path of the laser radiation in the plasma plume formed by the vertical take-off of the erosion products from the sample. A larger substance quantity is evaporated as a result of decreased absorption in the laser plume and the spectra obtained are more intense. The limits of detection for the elements are improved as well as the concentration sensitivity and reproducibility in laser microspectral analysis.

Preliminary laser sampling in the microspectral analysis of metals and alloys

A new form of collector for laser erosion products in the microspectral analysis of metals and alloys has been suggested and investigated. The collector is in the form of a thin graphite disc with an axial aperture for a laser beam to pass. This collector makes the best use of laser erosion products both in the stage of sampling and in that of excitation. To obtain low detection limits the collector is introduced into a d.c. are discharge using a carrier or into a hollow cathode discharge in the presence of a magnetic field.

Some criteria for standardization in laser microspectral analysis of minerals

Some criteria for standardization in laser microspectral analysis of minerals

Localization of a laser erosion crater in the microspectral analysis of refractories using an LMA-10 instrument

Localization of a laser erosion crater in the microspectral analysis of refractories using an LMA-10 instrument

Improvement of the Reproducibility and Sensitivity of Laser Microspectral Analysis

Abstract The possibility for the concentration sensitivity improvement and the limit of detection of the elements at a laser microspectral analysis is studied by means an absorbtion decrease of the laser emission in the plasma torch. From the investigations at an incline of 0°, 30°, 45°, 60° on the surface of the sample in the laser emission direction it is established, that the most intensive spectra are obtained at an incline of 45°. At an incline of 45° the intensity of certain spectral lines increases up 3 times in comparison with that of the horizontal surface of the sample. The limit of detection increases with one or two orders. The gradution curves for the determination of Si, Mn, Fe.

Laser microspectral analysis of steels

The use of laser microspectral analysis for the quantitative measurement of silicon and chromium, present in concentrations as low as 0.08% in mild steels, is investigated. A comparison is made between the use of Q-switched and normal ruby laser operation, both spark assisted. Time integrated electron temperature measurements of iron plasmas and time resolved spectra of A1 plasmas are presented and used to determine if the ‘local thermodynamic equilibrium’ model applies to these laser initiated plasmas.

LMA-1 apparatus for the microspectral analysis of certain minerals found in the kolsk peninsula

LMA-1 apparatus for the microspectral analysis of certain minerals found in the kolsk peninsula

Use of microspectral analysis to investigate sorption of xanthate on gold

Use of microspectral analysis to investigate sorption of xanthate on gold

Use of emission microspectral analysis to investigate distribution of elements in titanium alloys

Use of emission microspectral analysis to investigate distribution of elements in titanium alloys

Laser microspectral analysis of particles in single crystals of sodium iodide

Laser microspectral analysis of particles in single crystals of sodium iodide

A few examples of applying laser microspectral analysis in semiconductor engineering : Gerhard Mohaput and Gudrun Patzmann. JENA Review 4/1974 p. 252

A few examples of applying laser microspectral analysis in semiconductor engineering : Gerhard Mohaput and Gudrun Patzmann. JENA Review 4/1974 p. 252

Use of a unit for the microspectral analysis of alloys under industrial conditions

Use of a unit for the microspectral analysis of alloys under industrial conditions

MSL-1 equipment for microspectral emission analysis

MSL-1 equipment for microspectral emission analysis