Measuring the Process Parameters of the IBAD Method

Chromium nitride films are known as good protective layers for against both corrosion and wear. These coatings have been studied in detail during recent years. Their protective capability strongly depends on the deposition conditions. A modern method for preparing chromium nitride is the IBAD (Ion Beam Assisted Deposition) method. The main parameter determining the composition and properties of the films prepared by the IBAD method is the arrival ratio of impinging nitrogen ions to chromium atoms. In order to calibrate the ion beam XY-mechanical scanner with a Faraday cup, a detector was designed and constructed. By mathematical processing of the data, the flux of the nitrogen atoms was found. To obtain the flux of the chromium atoms the RBS and Talystep methods were used. Now, on the basis of this data, we can perform CrNx, coatings with controlled composition and properties

DLC Films Deposited by the DC PACVD Method

DLC (Diamond-Like Carbon) coatings have been suggested as protective surface layers against wear. However hard DLC coatings, especially those of greater thickness, have poor adhesion to substrates. We have used several ways to increase the adhesion of DLC coatings prepared by the PACVD (Plasma Assisted Chemical Vapour Deposition) method on steel substrates. One of these is the DC PACVD method for preparing DLC films

Evidence of near-field laser ablation inductively coupled plasma mass spectrometry (NF-LA-ICP-MS) at nanometre scale for elemental and isotopic analysis on gels and biological samples

Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) has been established as a powerful surface analytical method for local elemental analysis on metallic.. ceramic, geological or biological sample surfaces. Here we show a new way of nanometre scale analysis of elements on sample surfaces by near-field LA-ICP-MS (NF-LA-ICP-MS). This technique uses the near-field enhancement effect on the tip of a thin silver needle in a laser beam (Nd:YAG laser, wavelength 532 nm) on the sample surface. The thin silver needle was etched electrolytically in an electrochemical cell using a droplet of citric acid as electrolyte. For nanolocal analysis by NF-LA-ICP-MS on soft matter (e.g., on 2-D gels and biological samples) a small volume transparent laser ablation chamber was constructed and coupled to a double-focusing sector field inductively coupled plasma mass spectrometer (ICP-MS). A small amount of soft sample material is ablated at atmospheric pressure by a single laser shot in the near-field of the silver tip in the defocused Nd:YAG laser beam. The ablated material is transported with argon as carrier gas into the inductively coupled plasma (ICP) ion source of the sensitive double-focusing sector field mass spectrometer with reverse Nier-Johnson geometry. By single-shot analysis on 2-D gels and biological surfaces doped with uranium in the mu g g(-1) range using NF-LA-ICP-MS all enhancement of ion intensities of transient signals in comparison with the background signal of up to factor 60 was observed. In gels doped with isotopically enriched Cu-65 and Zn-67 spikes by NF-LA-ICP-MS (single shot analysis) ion intensities up to the n x 10(5) cps range and isotope ratios (U-235/U-238, Cu-65/Cu-63 and Zn-67/Zn-64) were measured at a lateral resolution ill the nanometre scale. Using the near-field effect in LA-ICP-MS, it was demonstrated that nanolocal analysis is possible in single-shot measurements of elements oil biological samples and on a eel surface with spatial resolution at the hundreds of nanometres range. This first experiment on near-field LA-ICP-MS opens up a new, challenging path for future applications ill nanoimaging of elements in life science, biology and medicine, e.g., for analyses of single cells, cell organelles or biological structures at nanometre range in order to detect neurodegenerative diseases, but also in material science, nanotechnologies and nanoelectronics

Copper, zinc, phosphorus and sulfur distribution in thin section of rat brain tissues measured by laser ablation inductively coupled plasma mass spectrometry: possibility for small-size tumor analysis

A microanalytical method using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) was developed to measure element distribution in rat brain tissues for the detection of a small-size tumor. The stereotaxically guided tumor was implanted by injecting 5 mu l of 10(3) F98 cells into the right Caudatus putamen of a male F344 Fisher rat brain hemisphere. The second non-treated rat brain hemisphere is used as control tissue. Tumor investigation of adjacent slices is carried out by LA-ICP-MS and, in addition, autoradiographically with a tritiated ligand (H-3-PK11195) of the peripheral benzodiazepine-receptor, which is not expressed in the brain under normal, physiological conditions but during tumor development. Ion intensities of Cu-63(+), Zn-64(+), P-31(+) and S-32(+) in the rat brain section (thickness: 20 mm; analyzed area 12 mm by 6 mm) containing the local tumor and control area were measured by scanning with a focused laser beam at wavelength 213 nm, diameter of laser crater 50 mu m and laser power density 3.10(9) W cm(-2), in a cooled laser ablation chamber coupled to a double-focusing sector field ICP-MS. The quantitative determination of element distribution in a thin slice of the rat brain tissue was carried out using matrix-matched laboratory standards. The mass spectrometric analysis yielded an inhomogeneous distribution for Cu, Zn, S and P in the analyzed rat brain sections. For Cu and Zn a deficiency in and around the tumor region in comparison with the control brain tissue of the second hemisphere was found. The detection limits for distribution analysis of Zn and Cu measured by LA-ICP-MS are in the ng g(-1) range. The capability and the limits of LA-ICP-MS will be studied for the imaging of element distribution in thin cross sections of brain tissues in order to create a new diagnostic method for the borders of small-size tumors

Biomotoring of environmental pollution by thorium and uranium in selected regions of the Republic Kazakhstan

Two former uranium mines and a uranium reprocessing factory in the city of Aktau, Kazakhstan, may represent a risk of contaminating the surrounding areas by uranium and its daughter elements. One of the possible fingerprinting tools for studying the environmental contamination is using plant samples, collected in the surroundings of this city in 2007 and 2008. The distribution pattern of environmental pollution by uranium and thorium was evaluated by determining the thorium and uranium concentrations in plant samples (Artemisia austriaca) from the city of Aktau and comparing these results with those obtained for the same species of plants from an unpolluted area (town of Kurchatov). The determination of the uranium and thorium concentrations in different parts of A. austriaca plants collected from the analyzed areas demonstrated that the main contamination of the flora in areas surrounding the city of Aktau was due to dust transported by the wind from the uranium mines. The results obtained demonstrate that all the areas surrounding Aktau have a higher pollution level due to thorium and uranium than the control area (Kurchatov). A few "hot points" with high concentrations of uranium and thorium were found near the uranium reprocessing factory and the uranium mines

Determination of phosphorus and metals in human brain proteins after isolation by gel electrophoresis by laser ablation inductively coupled plasma source mass spectrometry

Phosphorus, sulfur, silicon and metal concentrations (Al, Cu and Zn) were determined in human brain, proteins by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) after separation of protein mixtures by two dimensional (2-D) gel electrophoresis. The analysis of phosphorus, silicon and metals in single protein spots in the gel was' performed with an optimized microanalytical method using a double-focusing sector field inductively coupled plasma mass spectrometer coupled to a commercial laser ablation system (LA-ICP-MS). Relative ion intensities for P, Si and metals with respect to sulfur in protein spots were determined by LA-ICP-MS. The detection limits for phosphorus and sulfur in protein spots with a silver staining procedure on the 2-D gels were compared with the Coomassie staining technique described previously