Multifragmentation in Collisions of 4.4gev-Deuterons with Gold Target

The relative velocity correlation function of pairs of intermediate mass fragments has been studied for d+Au collitions at 4.4 GeV. Experimental correlation functions are compared to that obtained by multibody Coulomb trajectory calculations under the assumption of various decay timees of the fragmenting system. The combined approach with the empirically modified intranuclear cascade code followed by the statistical multifragmentation model was used to generate the starting conditions for these calculations. The fragment emossion time is found to be less than 40 fm/c.Comment: Accepted for publication in Bulletin of the Russian Academy of Sciences. Physic

In situ X-ray diffraction investigation of nitride coatings at high-temperature oxidation

Structural and phase researches of the multicomponent nanocrystalline coatings synthesized by plasma-assisted vacuum arc method at high-temperature influence by method of X-ray diffraction with the use of synchrotron radiation in situ have been carried out. The main features of these coatings are the superhardness (39 - 45 GPa) and nanocrystalline structure (5 - 20 nm). The analysis of results of structural and phase researches, physical and mechanical characteristics after oxidation of multicomponent nitride coatings at high-temperature heating in open air is presented

Морфология спор Parahemionitis arifolia (Cheilanthoideae, Pteridaceae)

A study of spores of the single species of the genus Parahemionitis Panigrahi was performed using the method of scanning electronic microscopy (SEM). Spores of Parahemionitis arifolia (Burm. f.) Panigrahi are tetrahedral trilete, roundish-triangular in polar position, with micro-wrinkled exospore and sculptured perispore. Sculpture of perispore is cristate-reticulate, cristae are quite regularly distributed and form reticulum with small mostly closed polygonal luminae of different shape. Laesura arms are often obscured by numerous cristae. Size of spores is 53–63 × 40–42 μm. Spores of P. arifolia are similar in perispore sculpture with those of species of some cheilanthoid ferns

Investigation of Anti-Relaxation Coatings for Alkali-Metal Vapor Cells Using Surface Science Techniques

Many technologies based on cells containing alkali-metal atomic vapor benefit from the use of anti-relaxation surface coatings in order to preserve atomic spin polarization. In particular, paraffin has been used for this purpose for several decades and has been demonstrated to allow an atom to experience up to 10,000 collisions with the walls of its container without depolarizing, but the details of its operation remain poorly understood. We apply modern surface and bulk techniques to the study of paraffin coatings, in order to characterize the properties that enable the effective preservation of alkali spin polarization. These methods include Fourier transform infrared spectroscopy, differential scanning calorimetry, atomic force microscopy, near-edge X-ray absorption fine structure spectroscopy, and X-ray photoelectron spectroscopy. We also compare the light-induced atomic desorption yields of several different paraffin materials. Experimental results include the determination that crystallinity of the coating material is unnecessary, and the detection of C=C double bonds present within a particular class of effective paraffin coatings. Further study should lead to the development of more robust paraffin anti-relaxation coatings, as well as the design and synthesis of new classes of coating materials.Comment: 12 pages, 12 figures. Copyright 2010 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in the Journal of Chemical Physics and may be found at http://link.aip.org/link/?JCP/133/14470

Condensation of a tetrahedra rigid-body libration mode in HoBaCo4O7 : the origin of phase transition at 355 K

Rietveld profiles, Moessbauer spectra and x-ray absorption fine structure (XAFS) were analyzed through the structural phase transition at Ts = 355 K in HoBaCo4O7. Excess of the oxygen content over O7 was avoided via annealing the samples in argon flow at 600 degree C. Space groups (S.G.) Pbn21c and P63mc were used to refine the structure parameters in the low- and high-temperature phases, respectively. Additionally, the Cmc21 symmetry was considered as a concurrent model of structure of the low-temperature phase. In the high-temperature phase, severe anisotropy of thermal motion of the major part of the oxygen atoms was observed. This anisotropic motion turns to be quenched as the sample is cooled below Ts. The variation of quadrupole splitting near Ts is not similar to a steplike anomaly frequently seen at the charge-ordering transition. We observe instead a dip-like anomaly of the average quadrupole splitting near Ts. Narrow distribution of the electric field gradient (EFG) over different cobalt sites is observed and explained on the basis of point-charge model. XAFS spectra show no evidence of significant difference between YBaCo4O7 (T > Ts) and HoBaCo4O7 (T < Ts). The origin of the transition at Ts is ascribed to the condensation of the libration phonon mode associated with the rigid-body rotational movements of the starlike tetrahedral units, the building blocks of kagome network. It is shown that the condensation of the libration mode is not compatible with translation symmetry for the hexagonal S.G., but compatible for the orthorhombic S.G. The orthorhombic lattice parameters and EFG components (Vxx, Vyy, Vzz) vary smoothly with temperature at approaching Ts and closely follow each other.Comment: 13 figure

The Monte Carlo Event Generator DPMJET-III

A new version of the Monte Carlo event generator DPMJET is presented. It is a code system based on the Dual Parton Model and unifies all features of the DTUNUC-2, DPMJET-II and PHOJET 1.12 event generators. DPMJET-III allows the simulation of hadron-hadron, hadron-nucleus, nucleus-nucleus, photon-hadron, photon-photon and photon-nucleus interactions from a few GeV up to the highest cosmic ray energies.Comment: 6 pages, Talk given at the Conference ``Monte Carlo 2000'', Lisbon, Portugal, 23-26 Oct. 200

On the taxonomical status of Aquilegia kansuensis (Ranunculaceae)

Для рода Aquilegia L. (Ranunculaceae) предложена новая номенклатурная комбинация – A. kansuensis (Brühl) Erst.DOI: 10.14258/turczaninowia.17.4.4 A new combination in the genus Aquilegia L. (Ranunculaceae) – A. kansuensis (Brühl) Erst have been proposed.DOI: 10.14258/turczaninowia.17.4.

Data on spore morphology of Cerosora microphylla (Anogramma microphylla) (Pteridaceae)

We used the method of scanning electron microscopy (SEM) to study the representatives of the genus Anogramma from South-West Asia and the Himalayas. To confirm the presence of Cerosora microphylla (Hook.) R.M. Tryon in China (hence, the absence of Anogramma microphylla (Hook.) Diels), we revealed the features of external morphology of spores that are not inherent in representatives of the genus Anogramma: absence of an equatorial ridge, roundish-triangular shape of the spores in the proximal-polar and distal-polar positions; absence of roller-like bulges extending upward in the form of ridges along the contour of the distal side of the spore; roller-like folds extending upward in the form of ridges both on the proximal and distal sides of the spore. In addition, one feature revealed for C. microphylla – spherical tubercles between the proximal and distal roller-like folds located along the spore equator – indicates its high species-specificity. We used the method of scanning electron microscopy (SEM) to study the representatives of the genus Anogramma from South-West Asia and the Himalayas. To confirm the presence of Cerosora microphylla (Hook.) R.M. Tryon in China (hence, the absence of Anogramma microphylla (Hook.) Diels), we revealed the features of external morphology of spores that are not inherent in representatives of the genus Anogramma: absence of an equatorial ridge, roundish-triangular shape of the spores in the proximal-polar and distal-polar positions; absence of roller-like bulges extending upward in the form of ridges along the contour of the distal side of the spore; roller-like folds extending upward in the form of ridges both on the proximal and distal sides of the spore. In addition, one feature revealed for C. microphylla – spherical tubercles between the proximal and distal roller-like folds located along the spore equator – indicates its high species-specificity.