Magnetoelectric CoFe2O4/polyvinylidene fluoride electrospun nanofibres

Magnetoelectric 0-1 composites comprising CoFe2O4 (CFO) nanoparticles in polyvinylidene fluoride (PVDF) polymerfibre matrix have been prepared by electrospinning. The average diameter of the electrospun composite fibres D is ~ 325 nm, independently of nanoparticle content, and the amount of crystalline polar β phase is strongly enhanced when compared to pure PVDF polymer fibres. The piezoelectric response of these electroactive nanofibres is modified by an applied magnetic field, thus evidencing the magnetoelectric character of the CFO/PVDF 0-1 composites.

Active magneto-optical control of spontaneous emission in graphene

We investigate the spontaneous emission rate of a two-level quantum emitter near a graphene-coated substrate under the influence of an external magnetic field or strain induced pseudo-magnetic field. We demonstrate that the application of the magnetic field can substantially increase or decrease the decay rate. We show that a suppression as large as 99$\%$ in the Purcell factor is achieved even for moderate magnetic fields. The emitter's lifetime is a discontinuous function of $|{\bf B}|$, which is a direct consequence of the occurrence of discrete Landau levels in graphene. We demonstrate that, in the near-field regime, the magnetic field enables an unprecedented control of the decay pathways into which the photon/polariton can be emitted. Our findings strongly suggest that a magnetic field could act as an efficient agent for on-demand, active control of light-matter interactions in graphene at the quantum level.

Desenvolvimento e teste de um sistema para caracterização de materiais magnetoelétricos

Dissertação de mestrado integrado em Engenharia Eletrónica Industrial e Computadores

Sistema de aquisição e comunicação para sensores magnetoelétricos

Dissertação de mestrado integrado em Engenharia Eletrónica Industrial e Computadores

Proving the suitability of magnetoelectric stimuli for tissue engineering applications

A novel approach for tissue engineering applications based on the use of magnetoelectric materials is presented. This work proves that magnetoelectric Terfenol-D/poly(vinylidene fluoride-co-trifluoroethylene) composites are able to provide mechanical and electrical stimuli to MC3T3-E1 pre-osteoblast cells and that those stimuli can be remotely triggered by an applied magnetic field. Cell proliferation is enhanced up to 25% when cells are cultured under mechanical (up to 110 ppm) and electrical stimulation (up to 0.115 mV), showing that magnetoelectric cell stimulation is a novel and suitable approach for tissue engineering allowing magnetic, mechanical and electrical stimuli.

Conformal symmetry of the critical 3D Ising model inside a sphere

We perform Monte-Carlo simulations of the three-dimensional Ising model at the critical temperature and zero magnetic field. We simulate the system in a ball with free boundary conditions on the two dimensional spherical boundary. Our results for one and two point functions in this geometry are consistent with the predictions from the conjectured conformal symmetry of the critical Ising model.

Pseudofermion dynamical theory for the spin dynamical correlation functions of the half-filled 1D Hubbard model

A modified version of the metallic-phase pseudofermion dynamical theory (PDT) of the 1D Hubbard model is introduced for the spin dynamical correlation functions of the half-filled 1D Hubbard model Mott– Hubbard phase. The Mott–Hubbard insulator phase PDT is applied to the study of the model longitudinal and transverse spin dynamical structure factors at finite magnetic field h, focusing in particular on the sin- gularities at excitation energies in the vicinity of the lower thresholds. The relation of our theoretical results to both condensed-matter and ultra-cold atom systems is discussed.

Optimization of magnetoelectric composites based on electroactive polymers for energy harvesting and sensor application

Tese de Doutoramento em Engenharia de Materiais.

Blow-up and finite time extinction for p(x, t)-curl systems arising in electromagnetism

"Available online 22 March 2016"

Development of a poly(L-Lactic acid) based drug release system

Dissertação de mestrado em Biofísica e Bionanossistemas

Об одной причине несовпадения наблюденных и пересчитанных магнитных полей на одну и туже высоту (на кавказе)

ნაშრომი ეხება ერთი და იგივე სიმაღლეზე გაზომილი და გადათვლილი მაგნიტური ველების არდამთხვევის მიზეზის გამოკვლევას. ავტორები თვლიან, რომ ერთი და იგივე სიმაღლეზე გაზომილი და გადათვლილი მაგნიტური ველების არდამთხვევის ერთ-ერთი მიზეზია, მაგმურ ქანებში, ვერტიკალური ზონალობა, ქანების ეფექტური დამაგნიტების მიმართულების მიხედვით.

Аномальные солнечно-суточные вариации космических лучей, связанные с пересечением Землей границ секторов межпланетного магнитного поля (ММП) и проблема землятрясеий

კოსმოსური სხივების ინტენსივობის მზე-დღეღამური ვარიაციების ანიზოტროპია დაკავშირებულია დედამიწის მიერ საპლანეტაშორისო მაგნიტური ველის (სმვ) ნეიტრალური ფენის გადაკვეთასთან.

Magnetische Beeinflussung von Pulsprozessen bei Vakuumbogenentladungen

Vacuum arc, magnetic field, pulsed process, spot movement, ion current, plasma properties, deposition rate

Data Processing at the Flaw Detector with Combined Multisector Eddy-Current Transducer

There is described data processing at the flaw detector with combined multisectional eddy-current transducer and heterofrequency magnetic field. The application of this method for detecting flaws in rods and pipes under the conditions of significant transverse displacements is described.

Dispositius nanoelectrònics a freqüències de THz : estudi de la propagació electromagnètica en les connexions

Per a altes freqüències, les connexions poden tenir un paper rellevant. Atès que la velocitat de propagació dels senyals electromagnètics, c, en el cable no és infinita, el voltatge i el corrent al llarg del cable varien amb el temps. Per tant, amb l’objectiu de reproduir el comportament elèctric de dispositius nanoelectrònics a freqüències de THz, en aquest treball hem estudiat la regió activa del dispositiu nanoelectrònic i les seves connexions, en un sistema global complex. Per a aquest estudi hem utilitzat un nou concepte de dispositiu anomenat Driven Tunneling Device (DTD). Per a les connexions, hem plantejat el problema a partir de tot el conjunt de les equacions de Maxwell, ja que per a les freqüències i longituds de cable considerats, la contribució del camp magnètic és també important. En particular, hem suposat que la propagació que és dóna en el cable és una propagació transversal electromagnètica (TEM). Un cop definit el problema hem desenvolupat un programa en llenguatge FORTRAN que amb l'algoritme de diferències finites soluciona el sistema global. La solució del sistema global s'ha aplicat a una configuració particular de DTD com a multiplicador de freqüència per tal de discutir quins paràmetres de les connexions permet maximitzar la potència real que pot donar el DTD.