Application of x-ray fluorescence analysis to investigation of the composition of gunshot residues

We have used x-ray fluorescence analysis to study the elemental composition of gunshot residues from smooth-bore and rifled-bore guns. We have established that it is possible to differentiate between types of projectiles (jacketed/lead), types of primers (corrosive/noncorrosive), and types of propellant powders (black/smokeless) by analysis of the elemental composition of the gunshot residues. We have shown that the mercury content in gunshot residues on the surface of the object carrying the residues steadily decreases as storage time increases. Despite this fact, mercury can be preserved as a component of gunshot residues on the object (cotton cloth) under room conditions for more than 45 days. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 3, pp. 320–325, May–June, 2006.     

Normalization of intensity curves in X-ray diffraction by disordered systems

The application of the method of graphic construction of the background line (widely used in electron diffraction analysis of amorphous films) to the normalization of X-ray intensity curves obtained by the “ reflection” method has been considered.     

Polynomial approximation of functions with given order of thekth generalized modulus of smoothness

The problem of approximation by algebraic polynomials is considered on function classes characterized by the value of thekth generalized modulus of smoothness defined by the Jacobi generalized shift operator. Translated fromMatematicheskie Zametki, Vol. 63, No. 3, pp. 425–436, March, 1998.     

Structure and physical properties of ternary NaF–LiF–LnF3 (Ln = La,Nd) systems of eutectic compositions

Ternary NaF–LiF–LnF₃ (Ln = La, Nd) systems of eutectic compositions were studied by means of X-ray diffraction method in the solid and liquid states. It was found that the crystalline phases LiF, NaF and NaLnF₄ coexist in the solid state up to the melting temperatures. Above the melting point, a decrease in the nearest interatomic distances with a pronounced minimum has been observed, which correlates with the extreme behaviour of the temperature-dependent structure-sensitive physical properties of the investigated alloys.     

Energy recovery LINAC: A next generation source for inelastic X-ray scattering

The Energy Recovery LINAC (ERL) being developed at Cornell should be an excellent source for Inelastic X-ray Scattering (IXS) because it will permit long undulators to operate at high efficiency generating unprecedented spectral flux (photons/second/meV) and brilliance. We discuss several advantages of the ERL for IXS experimentation.     

The relationship between thermodynamic properties and local atomic structure of Al-TM (TM = Mn,Fe, Co,Ni, Cu) melts

The relationship between structure and thermodynamic properties of Al- transition metal (TM) (TM = Mn, Fe, Co, Ni, Cu) melts had been studied by using the results of X-ray diffraction experiments, reverse Monte Carlo simulations and the model of ideal associated solution (MIAS). It was considered that local atomic structure of melts is determined by dense non-crystalline atomic packing and energy of interatomic interactions. This allowed to choose the types of associates for the MIAS. It is shown that the prominent role of the atomic packing factor in the Al-Mn, Al-Fe melts leads to correlation between the local atomic ordering of melts and the one of relevant polytetrahedral phases and defines a set of associates. Strengthening of heteroatomic interactions in the Al-Co, Al-Ni melts leads to an increase of the energy factor role in determining their structure and properties that reduces the number of associates from three for the Al-Mn melts to one for the Al-Ni.     

Reverse Monte Carlo and Voronoi-Delaunay simulation and structure analysis for liquid metals

This paper discusses the applicability of the integrated reverse Monte Carlo and Voronoi-Delaunay approach to local structure analysis and medium-scale structure determination of liquid metals. The advantages of this approach are shown: generation of 3D structural models using experimental diffraction data and subsequent structure determination by atomic coordinate analysis.Original Russian Text Copyright © 2004 by A. S. Roik, V. P. Kazimirov, and V. E. SokolskiiTranslated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 4, pp. 683–691, July–August, 2004.This revised version was published online in April 2005 with a corrected cover date.     

X-ray diffraction study of the structure of Al-Co melts

The structure of Al-Co melts with 0 at.%, 10 at.%, 18 at.%, 23.5 at.%, 26 at.%, 80.7 at.%, and 100 at.% Co has been studied by X-ray diffraction. Inverse Monte Carlo simulation using the experimental curves of the structural factor was employed to reconstruct the models of melts, analyzed by the Voronoi-Delaunay technique. The dependence of parameters that define short-and longer range ordering of atoms is nonmonotonous in the range 85–74 at.% Al and is extremal in the vicinity of a melt with 76.5 at.% Al. In the stated range of concentrations, the cobalt atoms basically lie at distances of ≈4.2 Å in the pentagonal rings of icosahedral type polytetrahedral clusters. Therefore one can speak about correlation in the character of atomic ordering in melts and corresponding periodic and quasiperiodic phases.