Search results for "Barrier"

A theoretical and experimental study of the racemization process of hexaaza[5]helicenes

2014

A dynamic 1H NMR study, together with DFT calculations, of bis-([1,2,3]triazolo)[1,5-a:5′,1′-k][1,10]phenanthroline 2 has allowed to identify the ring and open forms of a new example of ring/chain tautomerism, as well as their interconversion barriers (ring/ring and ring/open). The barrier of the exchange process between the chain forms and the ring form was found higher than the 'racemization' process in the closed form, so the ring opening does not contribute to the 'racemization'. The di-1,10-methyl and di-1,10-iodo derivatives have been prepared and their properties calculated.

Atmospheric pressure plasma polymerisation of metalloporphyrins containing mesoporous membranes for gas sensing applications

2013

Abstract Metalloporphyrins are embedded in an organosilicon matrix by an easily up-scalable atmospheric pressure dielectric barrier discharge method. The integrity of the metalloporphyrins, followed by UV–visible spectroscopy, is successfully preserved and their aggregation prevented. The single molecule properties, rather than the bulk ones, are thus enhanced. Exposure to triethylamine, which reaches the metalloporphyrins through the pores of the organosilicon membrane, led to a shift in the absorption spectrum and confirms the gas sensing potential of such coatings.

Investment and growth in Europe during the Golden Age

2009

During the ‘Golden Age’, the high investment rates reached by the European countries have been considered crucial in explaining growth. The literature about the Golden Age has emphasized supply-side explanations based on structural change, the reconstruction effort and the catch-up hypothesis, but also demand-side explanations focused on the effects of demand stability for promoting high rates of investment. In this article we have focused our attention on the evolution of the user cost of capital for explaining the high rates of investment. Our hypothesis is that the increase in investment rates was propelled by the decline in the user cost of capital, the consequence largely of the drop i…

In-situ annealing characterization of atomic-layer-deposited Al2O3 in N2, H2 and vacuum atmospheres

2019

Tarkista embargo, kun artikkeli julkaistu. Atomic-layer-deposited Al 2 O 3 films can be used for passivation, protective, and functional purposes in electronic devices. However, as-deposited, amorphous alumina is susceptible to chemical attack and corrosion during manufacturing and field-use. On the contrary, crystalline Al 2 O 3 is resistant against aggressive chemical treatments and corrosion. Here, high-temperature treatments in N 2 , H 2 , and vacuum were used to crystallize alumina which exhibited different crystalline phases. The annealing process was monitored continuously in situ by measuring the film temperature and surface reflectance to understand the crystallization kinetics. Ex…

Production and investigation of neutron-rich Osmium isotopes with and around N=126 using gas flow transport method

2014

Neutron-rich isotopes of heavy nuclei are until now poorly studied. In this work we investigate neutron-rich osmium isotopes produced in multi-nucleon transfer reactions. The reaction 136Xe+208Pb at energy near Coulomb barrier is used for production of osmium isotopes. The CORSAR-V setup is used to record the characteristics of osmium isotopes. The separation of the reaction products is based on their respective volatility. Experimental results are presented and discussed. © Published under licence by IOP Publishing Ltd.

Multinucleon transfer reactions: an overview of recent results

2012

Large acceptance magnetic spectrometers, such as PRISMA installed at Laboratori Nazionali di Legnaro, gave a further boost to the renewed interest for multinucleon transfer reactions in the last decade. The large solid angles of these devices and the high resolving powers of their detection systems allowed to investigate the transfer process around and well below the Coulomb barrier and to perform nuclear structure studies in several mass regions of the nuclide chart when coupled with large γ-ray arrays such as CLARA. Selected results obtained with the PRISMA-CLARA set-up in odd argon isotopes populated by using the multinucleon transfer process and in sub- barrier transfer measurements are…

I RODITORI DI CAVA MONTICINO (BRISIGHELLA, RA)

2021

Rodents are the most abundant group of small mammals occurring in Brisighella deposits. They are represented by 12 species in total, among which 2 hamsters (Apocricetus cf. barrierei and Ruscinomys cf. lasallei), 2 dormice (Muscardinus sp. and Myomimus sp.), 1 porcupine (Hystrix (Hystrix) depereti), 2 sciurids (Atlantoxerus cf. rhodius and Hylopetes sp.) and 5 species of muridae (Apodemus cf. gudrunae, Centralomys benericettii, Occitanomys sp, Paraethomys meini and Stephanomys debruijni). This association suggests a relatively dry open environment, interrupted by forest environment with more or less dense underground.

Current injection from metal to MoS2 probed at nanoscale by conductive atomic force microscopy

2016

Contacts with MoS2 are currently the object of many investigations, since current injection through metal/MoS2 interfaces represents one of the limiting factors to the performance of MoS2 thin film transistors. In this paper, we employed conductive atomic force microscopy (CAFM) to investigate the current injection mechanisms from a nanometric contact (a Pt coated tip) to the surface of MoS2 thin films exfoliated on SiO2. The analysis of local current-voltage (I-V) characteristics on a large array of tip positions provided high spatial resolution information on the lateral homogeneity of the tip/MoS2 Schottky barrier Phi(B) and of the ideality factor n. From the histograms of the measured P…

Polymer/metal hybrid multilayers modified Schottky devices

2013

Insulating, polymethylmethacrylate (PMMA), and semiconducting, poly(3-hexylthiophene) (P3HT), nanometer thick polymers/Au nanoparticles based hybrid multilayers (HyMLs) were fabricated on p-Si single-crystal substrate. An iterative method, which involves, respectively, spin-coating (PMMA and P3HT deposition) and sputtering (Au nanoparticles deposition) techniques to prepare Au/HyMLs/p-Si Schottky device, was used. The barrier height and the ideality factor of the Au/HyMLs/p-Si Schottky devices were investigated by current-voltage measurements in the thickness range of 1-5 bilayers. It was observed that the barrier height of such hybrid layered systems can be tuned as a function of bilayers …

EFFETTI IDRO-MORFODINAMICI DI UNA BARRIERA SOFFOLTA IN GEOTESSUTO

Nel periodo di dottorato si è valutato se queste barriere possono rappresentare delle valide alternative in termini idromorfodinamici alle barriere tradizionali per la protezione delle spiagge interessate da fenomeni di erosione costiera. La barriera è costituita da sacchi di geotessuto riempiti con sabbia prelevata in zone limitrofe all’area di intervento, preferibilmente cave marine presenti a largo. Le indagini sperimentali sono state condotte in scala in una canaletta marittima di laboratorio con fondo mobile sabbioso, considerando una disposizione dei sacchi ordinata (cioè disposti tutti longitudinalmente al canale e accuratamente assestati) ed una alla rinfusa; per la disposizione ord…