Search results for "Location"
showing 10 items of 1480 documents
Paternal effects on functional gender account for cryptic dioecy in a perennial plant.
2004
7 páginas, 3 figuras, 1 tabla.
Dislocations in AIIIBVI single crystals
1988
High densities of planar defects are evidenced in various AIIIBVI layer compounds by systematic electron microscopy observations with the dark-field weak-beam image technique. Several samples are analyzed, as obtained from different crystal ingots of InSe grown by the Bridgman-Stockbarger method, and some GaS and GaSe single crystals grown both, from the melt and from the vapour. The observed defects are identified mainly as screw and edge dislocations, the orientation of which is obtained in some cases by the analysis of the Moire fringes. Dislocation densities ranging between 108 and 1010 cm−2 are measured, not uniformly distributed in the various regions of each sample. Finally, the obse…
Hardening and formation of dislocation structures in LiF crystals irradiated with MeV–GeV ions
2002
Abstract Material modifications of LiF crystals irradiated with Au, Pb and Bi ions of MeV to GeV energy are studied by means of microindentation measurements and dislocation etching. Above a critical irradiation fluence of 10 9 ions/cm 2 , the microhardness can improve by a factor of 2 in the bulk and by more than 3 on the surface. Radiation-induced hardening follows the evolution of the energy loss along the ion path. Annealing experiments indicate that complex defect aggregates created in the tracks play a major role for the hardness change. Evidence for severe structural modifications is found when etching indentation impressions in highly irradiated crystals leading to similar pattern a…
The liquid-solid transition of hard discs: first-order transition or Kosterlitz-Thouless-Halperin-Nelson-Young scenario?
2002
We consider the question of whether a two-dimensional hard-disc fluid has a first-order transition from the liquid state to the solid state as in the three-dimensional melting-crystallization transition or whether one has two subsequent continuous transitions, from the liquid to the hexatic phase and then to the solid phase, as proposed by Kosterlitz, Thouless, Halperin, Nelson and Young (KTHNY). Monte Carlo (MC) simulations of the fluid that study the growth of the bond orientational correlation length, and of the crystal are discussed. The emphasis is on a recent consistency test of the KTHNY renormalization group (RG) scenario, where MC simulations are used to estimate the bare elastic c…
Atmosphere-Induced Effect in Microhardness, Dislocation Mobility and Plasticity of C60and Graphite Crystals
1997
Abstract Formation of hard, brittle and toluene-insoluble near-surface layer (∼0.3 μm) of C60 crystals under atmospheric exposure was observed. Similar atmosphere-induced effect was found for graphite crystals and might also be expected for other molecular solids. Data on ageing kinetics of C60 and graphite crystals are presented. Variation of hardness with indentation depth can be described by the microhardness model for bilayer medium with different mechanical properties. Specific feature of C60 and graphite crystals is that no size effect appears in the intrinsic microhardness and dislocation mobility characteristics in the indentation depth range of 0.6–4μm.
<title>Heavy-ion induced damage and reduction of dislocation mobility in LiF single crystals</title>
2006
Ion-induced reduction of dislocation mobility in LiF crystals irradiated with swift heavy (U) and light (Ni) ions of a specific energy of 11 MeV per nucleon at fluences between 106 and 1011 ions/cm2 was studied. The arm length of dislocation rosettes produced by indentation on (100) irradiated surface was measured. It has been found that in the case of heavy ions the threshold fluence (106 ions/cm2) for impeding of dislocation arms is about 3 orders of magnitude lower than that for light ions. The results indicate that ion-induced defect aggregates play the dominating role in the impeding of dislocations. Heavy ions, which produce defect aggregates in the track core, cause also a stronger e…
Size-dependent alignment of Fe nanoparticles upon deposition onto W(110)
2010
Using in situ electron diffraction we study the orientation of mass-selected iron nanoparticles upon deposition onto single crystalline W(110) at room temperature. It is found that particles with a diameter below about 4 nm and a kinetic energy $\ensuremath{\le}0.1$ electron volt per atom spontaneously align with respect to the substrate. Larger particles preferentially rest with their (001) and (110) facets parallel to the surface, but do not show further alignment. The data may hint at thermally activated dislocation motions upon the impact on the substrate which are responsible for the observed orientation below 4 nm. By this uniformly oriented monodisperse nanostructures can be prepared…
Multidimensional scaling and stock location assignment in a warehouse: an application
1999
By means of an application, in the present paper, the suitability of a multivariate statistical methodology, as multidimensional scaling (MDS), to solve an optimization problem is shown. In particular, considering the stock location assignment problem in the warehouse of a supermarket chain, the solution gained by applying MDS to a set of seven variables is compared with the one obtainable by considering the usual techniques applied in this context. A wide discussion of results is reported.
Nuclear Translocation of Mismatch Repair Proteins MSH2 and MSH6 as a Response of Cells to Alkylating Agents
2000
Mammalian mismatch repair has been implicated in mismatch correction, the prevention of mutagenesis and cancer, and the induction of genotoxicity and apoptosis. Here, we show that treatment of cells specifically with agents inducing O(6)-methylguanine in DNA, such as N-methyl-N'-nitro-N-nitrosoguanidine and N-methyl-N-nitrosourea, elevates the level of MSH2 and MSH6 and increases GT mismatch binding activity in the nucleus. This inducible response occurs immediately after alkylation, is long-lasting and dose-dependent, and results from translocation of the preformed MutSalpha complex (composed of MSH2 and MSH6) from the cytoplasm into the nucleus. It is not caused by an increase in MSH2 gen…
Cluster-Based Relocation of Stations for Efficient Forest Fire Management in the Province of Valencia (Spain)
2021
Forest fires are undesirable situations with tremendous impacts on wildlife and people&rsquo