Učinak druge faze topologije čestica pri početnoj temperaturi abnormalnog rasta zrna kod Fe – 3% Si čelika

The relations between regimes of dynamic annealing, state of secondary particles system and the onset temperature of abnormal grain growth are investigated. Two distinguish types of Fe-3%Si grain-oriented steels, after one and two stage cold rolling, were studied. The second phase particles remain unaffected in first type of steel during the heat treatment. Vice versa, the increased density of second phases was observed after annealing in the second type of the investigated materials. It is shown that start/onset of abnormal grain growth strongly depends on both volume fraction of second phase particles and annealing temperature. Texture and magnetic properties of the investigated samples are investigated within the current study.Istraživani su odnosi između režima dinamičkog žarenja, stanja sustava sekundarnih čestica i početne temperature abnormalnog rasta zrna. Analizirane su dvije različite vrste Fe-3%Si zrnato usmjerenih čelika, nakon prve i druge faze hladnog valjanja. Čestice druge faze ostaju nepromijenjene kod prve vrste čelika tijekom toplinske obrade. Obrnuto, uočena je povećana gustoća u drugoj fazi nakon žarenja kod druge vrste ispitanih materijala. Prikazano je da početak abnormalnog rasta zrna uvelike ovisi i o opsegu čestica druge faze i o temperaturi žarenja. Ova analiza istražuje teksturu i magnetska svojstva ispitanih uzoraka

Excitons in coupled InAs/InP self-assembled quantum wires

Optical transitions in coupled InAs/InP self-assembled quantum wires are studied within the single-band effective mass approximation including effects due to strain. Both vertically and horizontally coupled quantum wires are investigated and the ground state, excited states and the photoluminescence peak energies are calculated. Where possible we compare with available photo-luminescence data from which it was possible to determine the height of the quantum wires. An anti-crossing of the energy of excited states is found for vertically coupled wires signaling a change of symmetry of the exciton wavefunction. This crossing is the signature of two different coupling regimes.Comment: 8 pages, 8 figures. To appear in Physical Review

Kvantifikacija mikrostrukture i vrednovanje mehaničkih svojstava u neorijentiranim elektro čelicima

This paper presents an original method of the estimation of average grain size in microstructure of broad grain size distribution and the parameter, describing the homogeneity of microstructure. The coefficient of microstructure homogeneity is defined. The mechanical properties of non-oriented electrical steels are predicted using new equation of grain size estimation.Ovaj rad predstavlja originalnu metodu utvrđivanja prosječne veličine zrna u mikrostrukturi prosječne veličine zrna i parametra te strukture opisivanjem njene homogenosti. Definiran je koeficijent homogenosti takve mikro-strukture. Mehanička svojstva neorijentiranih elektro čelika su predviđena novom jednadžbom za utvrđivanje veličine zrna

Sekundarna rekristalizacija u ne orijentiranim elektročelicima

Modelling of kinetics of grain growth process after primary recrystallisation in different types of non-oriented electrical steels is discussed. The ferrite grain growth behaviour during secondary recrystallization was analysed by applying the general equation for grain growth. The activation energy for grain boundary motion in both semi-processed and fully processed steels was calculated. An idea of anisotropic mobilities is applied to the columnar grain growth description. It is shown that the value of activation energy for columnar grain development along progress normal direction is higher than the one for rolling direction.Raspravljeno je modeliranje kinetike procesa rasta zrna nakon primarne rekristalizacije za različite vrste neorijetiranih elektročelika. Rast feritnog zrna tijekom sekundarne rekristalizacije analiziran je uporabom opće jednadžbe rasta zrna. Izračunata je energija aktivacije za gibanje granice zrna za poluobrađene i potpuno obrađene čelike. Za opis rasta stubičastih zrna korištena je ideja anizotropne pokretljivosti. Pokazana je da je vrijednost energije aktivacije za nastajanje stubičastog zrna veća u smjeru okomitom na smjer valjanja nego u smjeru valjanja

High-field magnetoexcitons in unstrained GaAs/AlxGa1-xAs quantum dots

The magnetic field dependence of the excitonic states in unstrained GaAs/AlxGa1-xAs quantum dots is investigated theoretically and experimentally. The diamagnetic shift for the ground and the excited states are studied in magnetic fields of varying orientation. In the theoretical study, calculations are performed within the single band effective mass approximation, including band nonparabolicity, the full experimental three-dimensional dot shape and the electron-hole Coulomb interaction. These calculations are compared with the experimental results for both the ground and the excited states in fields up to 50 Tesla. Good agreement is found between theory and experiment

Disease modifying and antiangiogenic activity of 2-Methoxyestradiol in a murine model of rheumatoid arthritis

<p>Abstract</p> <p>Background</p> <p>A critical component of disease progression in rheumatoid arthritis (RA) involves neovascularization associated with pannus formation. 2-methoxyestradiol (2ME2) is a naturally occurring molecule with no known physiologic function, although at pharmacologic concentrations it has antiproliferative and antiangiogenic activities. We investigated the impact of orally administered 2ME2 on the initiation and development of proliferative synovitis using the anti-collagen monoclonal antibodies (CAIA) model.</p> <p>Methods</p> <p>Severe polyarticular arthritis was induced in Balb/c female mice by administration of 2 mg of a monoclonal antibody cocktail intravenously into the tail vein of mice. Twenty-four hours following monoclonal antibody administration, mice were injected with 25 μg of LPS (<it>E. coli </it>strain 0111:B4) via the intraperitoneal route. Treatment with 2ME2 (100, 75, 50, 25, 10, 1 mg/kg, p.o., daily), or vehicle control began 24 hrs following LPS challenge and continued to day 21. Hind limbs were harvested, sectioned and evaluated for DMARD activity and general histopathology by histomorphometric analysis and immunohistochemistry (vWF staining). In a separate study, different dosing regimens of 2ME2 (100 mg/kg; q.d. <it>vs </it>q.w. <it>vs </it>q.w. × 2) were evaluated. The effect of treatment with 2ME2 on gene expression of inflammatory cytokines and angiogenic growth factors in the joint space was evaluated 5 and 14 days after the induction of arthritis.</p> <p>Results</p> <p>Mice treated with 2ME2 beginning 24 hours post anti-collagen monoclonal antibody injection, showed a dose-dependent inhibition in mean arthritic scores. At study termination (day 21), blinded histomorphometric assessments of sectioned hind limbs demonstrated decreases in synovial inflammation, articular cartilage degradation, pannus formation, osteoclast activity and bone resorption. At the maximal efficacious dosing regimen (100 mg/kg/day), administration of 2ME2 resulted in total inhibition of the study parameters and prevented neovascularization into the joint. Examination of gene expression on dissected hind limbs from mice treated for 5 or 14 days with 2ME2 showed inhibition of inflammatory cytokine message for IL-1β, TNF-α, IL-6 and IL-17, as well as the angiogenic cytokines, VEGF and FGF-2.</p> <p>Conclusion</p> <p>These data demonstrate that in the CAIA mouse model of RA, 2ME2 has disease modifying activity that is at least partially attributable to the inhibition of neovascular development. Further, the data suggests new mechanistic points of intervention for 2ME2 in RA, specifically inhibition of inflammatory mediators and osteoclast activity.</p