DC spin generation by junctions with AC driven spin-orbit interaction

An unbiased one-dimensional weak link between two terminals, subjected to the Rashba spin-orbit interaction caused by an AC electric field which rotates periodically in the plane perpendicular to the link, is shown to inject spin-polarized electrons into the terminals. The injected spin-polarization has a DC component along the link and a rotating transverse component in the perpendicular plane. In the adiabatic, low rotation-frequency regime, these polarization components are proportional to the frequency. The DC component of the polarization vanishes for a linearly-polarized electric field.Comment: published versio

Thermoelectrical manipulation of nanomagnets

We investigate the interplay between the thermodynamic properties and spin-dependent transport in a mesoscopic device based on a magnetic multilayer (F/f/F), in which two strongly ferromagnetic layers (F) are exchange-coupled through a weakly ferromagnetic spacer (f) with the Curie temperature in the vicinity of room temperature. We show theoretically that the Joule heating produced by the spin-dependent current allows a spin-thermo-electronic control of the ferromagnetic-to-paramagnetic (f/N) transition in the spacer and, thereby, of the relative orientation of the outer F-layers in the device (spin-thermo-electric manipulation of nanomagnets). Supporting experimental evidence of such thermally controlled switching from parallel to antiparallel magnetization orientations in F/f(N)/F sandwiches is presented. Furthermore, we show theoretically that local Joule heating due to a high concentration of current in a magnetic point contact or a nanopillar can be used to reversibly drive the weakly ferromagnetic spacer through its Curie point and thereby exchange couple and decouple the two strongly ferromagnetic F-layers. For the devices designed to have an antiparallel ground state above the Curie point of the spacer, the associated spin-thermionic parallel-to-antiparallel switching causes magneto-resistance oscillations whose frequency can be controlled by proper biasing from essentially DC to GHz. We discuss in detail an experimental realization of a device that can operate as a thermo-magneto-resistive switch or oscillator.Comment: This paper, published in J. Appl. Phys. 107, 123706 (2010), is an expanded version of arXiv:0710.5477 (8 pages, 12 figures, two additional authors and experimental section added

Nanomechanical manipulation of superconducting charge-qubit quantum networks

We suggest a nanoelectromechanical setup and corresponding time-protocol for controlling parameters in order to demonstrate nanomechanical manipulation of superconducting charge-qubit quantum network. We illustrate it on an example reflecting important task for quantum information processing - transmission of quantum information between two charge-qubits facilitated by nanomechanics. The setup is based on terminals utilizing the AC Josephson effect between bias voltage-controlled bulk superconductors and mechanically vibrating mesoscopic superconducting grain in the regime of the Cooper pair box, controlled by the gate voltage. The described manipulation of quantum network is achieved by transduction of quantum information between charge-qubits and intentionally built nanomechanical coherent states, which facilitate its transmission between qubits. This performance is achieved using quantum entanglement between electrical and mechanical states.Comment: 8 pages, 4 figure

Transduction of quantum information from charge qubit to nanomechanical cat-state

We suggest a nanoelectromechanical setup and corresponding time protocol of its manipulation by which we transduce quantum information from charge qubit to nanomechanical cat state. The setup is based on the AC Josephson effect between bulk superconductors and mechanically vibrating mesoscopic superconducting island in the regime of the Cooper pair box. Starting with a pure state with quantum information initially encoded into superposition of the Cooper pair box states, applying a specially tailored time protocol upon bias voltage and gate electrodes, we obtain a new pure state with information finally encoded into superposition of nanomechanical coherent states constituting the cat state. This performance is achieved using quantum entanglement between electrical and mechanical states. Nanomechanical cat states serve as a storage of quantum information, motivated by significantly longer decoherence time with respect to the charge qubit states, from which the information can be transdued back to the charge qubit applying the reverse time protocol.Comment: 6 pages, 4 picture

Spin-thermo-electronic oscillator based on inverse giant magnetoresistance

A spin-thermo-electronic valve with the free layer of exchange-spring type and inverse magnetoresistance is investigated. The structure has S-shaped current-voltage characteristics and can exhibit spontaneous oscillations when integrated with a conventional capacitor within a resonator circuit. The frequency of the oscillations can be controlled from essentially dc to the GHz range by the circuit capacitance.Comment: 7 pages, 9 figure

Primjena tehnologije rekombinantne DNA za pripravke kolinesteraza kao antidota i detektora organofosfata

To develop new avenues for synthesizing novel antidotes for organophosphate poisoning and for detection of the organophosphates, we have turned to recombinant DNA methods to synthesize cholinesterases with unusual properties. For antidotal therapy we describe mutations of the native mouse and human enzymes that allow for enhanced rates of oxime reactivation. Such enzymes, when localized in the circulation, would enable the circulating cholinesterase to become a catalytic rather than simply a stoichiometric scavenger. Hence, “oxime-assisted catalysis” provides a means for scavenging the organophosphates in the circulation thereby minimizing their tissue penetration and toxicity. Accordingly, the oxime antidote or prophylactic agent has a dual action within the circulation and at the tissue level. Second, through a novel chemistry, termed freeze-frame, click chemistry, we have used organophosphate conjugates of acetylcholinesterase as templates for the synthesis of novel nucleophilic reactivating agents. Finally, acetylcholinesterase can be modified through cysteine substitution mutagenesis and attachment of fluorophores at the substitution positions. When linked at certain locations in the molecule, the attached fluorophore is sensitive to organophosphate conjugation with acetylcholinesterase, and thus the very target of insecticide or nerve agent action becomes a detection molecule for organophosphate exposure.Razvijajući novi pristup sintezi antidota pri otrovanju organofosfatima kao i njihovu detekciju, primijenili smo metode rekombinantne DNA za pripremu kolinesteraza s neuobičajenim svojstvima. Za antidotsku terapiju istražili smo mutacije prirodnih enzima miša i čovjeka koje povećavaju brzine reaktivacije oksimom. Takvi enzimi bi po unosu u cirkulaciju postali katalitički, a ne samo stehiometrijski odstranjivači organofosfata. Na taj način “oksimom potpomognuta kataliza” omogućava čišćenje organofosfata iz cirkulacije umanjujući prodiranje organofosfata u tkiva i njihovu toksičnost. Prema tome, oksim kao antidot ima dvojaku ulogu: u cirkulaciji i na razini tkiva. S druge strane, uporabom novog sintetskog pristupa u oblikovanju biološki aktivnih spojeva poznatog kao “klik kemija” diskretnih proteinskih konformacija, organofosforilirani konjugati acetilkolinesteraze služe kao kalup u sintezi novih nukleofilnih reaktivatora. Naposljetku, acetilkolinesteraza se može mutagenezom modificirati uvo|enjem cisteina na koje se mogu vezati fluorofori. Fluorofori uvedeni na određena mjesta u molekuli acetilkolinesteraze mijenjaju svoja fluorescentna svojstva pri konjugaciji organofosfata s enzimom koji na taj način od objekta djelovanja insekticida i živčanih bojnih otrova postaje molekula za detekciju izloženosti organofosfatima

Petojezični rečnik termina metalurgije praha : (srpskohrvatsko-ruski, englesko-ruski, nemačko-ruski, francusko-ruski). Deo 2

Petojezični rečnik termina metalurgije praha : (srpskohrvatsko-ruski, englesko-ruski, nemačko-ruski, francusko-ruski). Deo 2 / I. I. Kovenski ... [i dr.] ; u redakciji M. M. Ristića i A. N. Piljankeviča. - Beograd : Srpska akademija nauka i umetnosti : Institut tehničkih nauka Srpske akademije nauka i umetnosti : Univerzitet u Beogradu, 1983 (Beograd : Zavod za grafičku tehniku Tehnološko-metalurškog fakulteta Univerziteta u Beogradu). - 442 p. ; 24 cm.- (Posebna izdanja / Srpska akademija nauka i umetnosti [i] Institut tehničkih nauka SANU ; t. 552.Odeljenje tehničkih nauka ; knj. 24