Surface spin flip probability of mesoscopic Ag wires

Spin relaxation in mesoscopic Ag wires in the diffusive transport regime is studied via nonlocal spin valve and Hanle effect measurements performed on permalloy/Ag lateral spin valves. The ratio between momentum and spin relaxation times is not constant at low temperatures. This can be explained with the Elliott-Yafet spin relaxation mechanism by considering the momentum surface relaxation time as being temperature dependent. We present a model to separately determine spin flip probabilities for phonon, impurity and surface scattering and find that the spin flip probability is highest for surface scattering.Comment: 5 pages, 4 figure

Evidence of Vortex Jamming in Abrikosov Vortex Flux Flow Regime

We report on dynamics of non-local Abrikosov vortex flow in mesoscopic superconducting Nb channels. Magnetic field dependence of the non-local voltage induced by the flux flow shows that vortices form ordered vortex chains. Voltage asymmetry (rectification) with respect to the direction of vortex flow is evidence that vortex jamming strongly moderates vortex dynamics in mesoscopic geometries. The findings can be applied to superconducting devices exploiting vortex dynamics and vortex manipulation, including superconducting wires with engineered pinning centers.Comment: 5 pages, 3 figure

Theoretical and empirical evaluation of the new neoclassical synthesis

Apstrakt: Razvoj makroekonomije tokom XX veka obeležen je brojnim teorijskim kontroverzama, revolucijama i kontrarevolucijom. Ipak, pored razlika u polaznim pretpostavkama teorijskih pravaca u okviru dve struje glavnog toka ekonomske misli (kejnzijanske i neoklasične), postojala je tendencija približavanja njihovih stavova u pogledu ključnih ekonomskih pitanja. Ovi procesi doveli su do uspostavljanja neoklasične sinteze, koja je bila aktuelna do sedamdesetih godina prošlog veka. Neoklasična kontrarevolucija, koja je usledila, reafirmisala je neka od predkejnzijanskih shvatanja, ali i podstakla nastanak novog kejnzijanizma. Međutim, tokom devedesetih godina, razlike između suprotstavljenih strana su počele da se smanjuju, što je omogućilo postizanje konsenzusa, koji je, po analogiji sa „starom“ sintezom, nazvan novom neoklasičnom sintezom. U skladu sa tim, predmet istraživanja u doktorskoj disertaciji je evaluacija teorijskog okvira nove neoklasične sinteze, kroz detaljnu elaboraciju njenih konstitutivnih elemenata. Putem sučeljavanja stavova ekonomskih škola glavnog toka, kao i heterodoksnih teorija, ispitano je da li nova neoklasična sinteza predstavlja najviši stupanj u dosadašnjem razvoju makroekonomske teorije. Na bazi analize mikroekonomskih osnova i njihovih makroekonomskih implikacija, kao i pristupa monetarnoj i fiskalnoj politici, u radu se daje ocena validnosti makroekonomskog modela nove sinteze u kontekstu njegovog nastanka, ali i događaja koji su izazvali Veliku Recesiju 2008. godine. Osnovni zaključak je da se efikasnost ovog modela u predstavljanju savremenih privreda i davanju projekcija može održati uvođenjem elemenata vezanih za funkcionisanje finansijskog sektora. Pored teorijske, u radu je izvršena i empirijska analiza ključnih elemenata nove sinteze. Na primeru odabranih razvijenih i tranzicionih zemalja ispitana je održivost teze o odnosu stvarne nezaposlenosti i NAIRU stope, kao i determinantama ove stope. Istražena je i validnost novokejnzijanske Filipsove krive, koja ima značajno mesto u modelu nove neoklasične sinteze. Generalno, rezultati empirijskog istraživanja su potvrdili ispravnost pristupa nove neoklasične sinteze ovim problemima, kao i polaznu pretpostavku da postoje kvalitativne razlike između podobnosti modela nove sinteze za analizu privreda razvijenih i tranzicionih zemalja.Abstract: The development of macroeconomics during the twentieth century was marked by many theoretical controversies, revolutions, and a counter-revolution. Despite the differences in the starting assumptions of theoretical approaches within two currents of the mainstream of economic thought (Keynesian and neoclassical), there was a tendency to converge their views on key economic issues. These processes have led to the establishment of Neoclassical Synthesis, which was current until the seventies. Neoclassical counterrevolution that followed reaffirmed some of the pre-Keynesian views, but also induced the emergence of the New Keynesianism. However, during the nineties, the differences between the parties began to decrease, which allowed reaching a consensus, which is, by analogy with the "old" synthesis, called the New Neoclassical Synthesis. Accordingly, the subject of the doctoral dissertation research is to evaluate theoretical framework of the New Neoclassical Synthesis, through detailed elaboration of its constituent elements. By confronting the views of mainstream economic schools, as well as heterodox theories, it was investigated whether the New Neoclassical Synthesis represents the highest level of the current development in macroeconomic theory. Based on the analysis of microeconomic foundations and their macroeconomic implications, as well as approach to monetary and fiscal policy, the paper assesses the validity of macroeconomic model of the New Synthesis in the context of its creation, but also events that caused the Great Recession of 2008. The main conclusion is that the efficiency of this model in presenting modern economies and projecting can be maintained by introducing elements related to financial sector functioning. In addition to theoretical analysis, the key elements of the New Synthesis were also empirically analyzed. The subject of empirical investigation was viability of the thesis on the relationship between actual unemployment and the NAIRU rate, as well as determinants of the rate, in the case of selected developed and transition countries. The validity of the New-Keynesian Phillips Curve, which has a significant place in the model of the New Neoclassical Synthesis, was analyzed as well. Overall, the results of empirical research have confirmed the accuracy of the New Neoclassical Synthesis approach to these issues, as well as the initial assumption that there are qualitative differences between suitability of the New Synthesis Model for analyzing economies of developed and transition countries

Synthesis of crystaline silicon oxynitride composites

Silicon oxynitride / silicon nitride (Si2N2O/Si3N4) ceramics have been prepared from Si3N4 powder and amorphous silica (SiO2) by hot pressing at different temperature. It was found that material sintered at lower temperature exhibit fine composite structure composed of equiaxed α-Si3N4 grains and Si2N2O crystals. At higher temperature the growing of Si2N2O particles as well as phase transformation from α-Si3N4 to β-Si3N4 phase take place.Physical chemistry 2006 : 8th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 26-29 September 200

Radioactivity measurements in soils surrounding four coal-fired power plants in Serbia by gamma-ray spectrometry and estimated dose

The study of spatial distribution of activity concentration of U-238, Ra-226, (210)pb, Th-232, K-40 and Cs-237 radionuclides in the surface soil samples (n = 42) collected in the vicinity of four coal-fired power plants in Serbia is presented. Radioactivity measurements in soils performed by gamma-ray spectrometry showed values [Bqkg(-1)] in the range: 15-117 for U-238, 21-115 for Ra-226, 33-65 for (210)pb, 20-69 for Th-232, 324-736 for K-40, and 2-59 for Cs-137. Surface soil radioactivity that could have resulted from deposition of radionuclides from airborne discharges or resuspension of ash from disposal sites showed no enhanced levels. It was found that variation of soil textural properties, pH values, and carbonate content influenced activity levels of natural radionuclides while radiocesium activities were associated with soil organic matter content. Modification of some soil properties was observed in the immediate vicinity ( lt 1 km) of power plants where the soil was more alkaline with coarser particles (0.2-0.05 mm) and carbonates accumulated. Calculated average values of the absorbed gamma dose rate and annual external effective dose originating from the terrestrial radionudides were 69.4 nGy/h and 0.085 mSv, respectively

Photocatalytic activity of peg-modified catalysts

This work is focused on the influence of polyethylene glycol (PEG) on structural, textural and photocatalytic properties of titanium dioxide (TiO2) catalyst. Catalysts were synthesized by sol-gel method using PEG with different molecular weight (600 and 10000) as pore generating agent. The results showed that PEG enhances not only porous structure but also change anatase to rutile ratio. The photocatalytic activity of the synthesized catalyst was measured by decomposition of phenol. The order of catalyst photoactivity was: TiO2/P600>TiO2/P10000>TiO2.The difference in catalyst photoactivity is attributed to their surface area and anatase fraction, rather then pore size

Photocatalytic activity of peg-modified catalysts

This work is focused on the influence of polyethylene glycol (PEG) onstructural, textural and photocatalytic properties of titanium dioxide (TiO2)catalyst. Catalysts were synthesized by sol-gel method using PEG withdifferent molecular weight (600 and 10000) as pore generating agent. Theresults showed that PEG enhances not only porous structure but also changeanatase to rutile ratio. The photocatalytic activity of the synthesized catalystwas measured by decomposition of phenol. The order of catalystphotoactivity was: TiO2/P600>TiO2/P10000>TiO2.The difference in catalystphotoactivity is attributed to their surface area and anatase fraction, ratherthen pore size

Supplementary data for the article: Savić, B. G.; Stanković, D. M.; Živković, S. M.; Ognjanović, M. R.; Tasić, G. S.; Mihajlović, I. J.; Brdarić, T. P. Electrochemical Oxidation of a Complex Mixture of Phenolic Compounds in the Base Media Using PbO2-GNRs Anodes. Applied Surface Science 2020, 529, 147120. https://doi.org/10.1016/j.apsusc.2020.147120

Supplementary material for: [https://doi.org/10.1016/j.apsusc.2020.147120]Related to published version: [https://cherry.chem.bg.ac.rs/handle/123456789/4177