Lexical availability is an area of knowledge which aims at discovering those words which come imm... more Lexical availability is an area of knowledge which aims at discovering those words which come immediately and naturally to our mind when the conversation turns on a series of stimuli. Our research focuses on the available vocabulary of 280 students from Romanian-Spanish bilingual primary schools and high-schools. The participants in the lexical availability test were studying Spanish as a foreign language in primary schools Federico García Lorca and Uruguay, which offered intensive courses of 4 hours per week, and in bilingual high-schools Miguel de Cervantes, Resumen: La disponibilidad léxica es un campo que persigue conocer aquellas palabras que vienen de forma inmediata y natural a la mente cuando la conversación gira en torno a una serie de estímulos verbales. Nuestra investigación se centra en el vocabulario disponible de doscientos ochenta estudiantes de colegios e institutos bilingües rumano-españoles de Bucarest. El objetivo principal de este estudio es averiguar si los factores 'sexo' y 'haber visitado un país hispanohablante' inciden en el léxico disponible de español como lengua extranjera. El análisis cuantitativo y cualitativo de cada una de estas variables, junto con su correlación con el 'nivel de estudios', saca a la luz resultados destacados cuya explicación solo puede encontrarse en otras disciplinas, como son la sociolingüística o las ciencias cognitivas.
Abstracts, Resuscitation 2011 -Implementation / Resuscitation 82S1 (2011) S1-S34 S17 their wavefo... more Abstracts, Resuscitation 2011 -Implementation / Resuscitation 82S1 (2011) S1-S34 S17 their waveform, which in its turn can influence defibrillation thresholds (DT). The aim of the study was to compare DT in two different biphasic waveforms on high impedance porcine model.
We investigated the behaviour of YBa2Cu2O7-δ ceramics by multiharmonic ac-susceptibility. We have... more We investigated the behaviour of YBa2Cu2O7-δ ceramics by multiharmonic ac-susceptibility. We have found an unexpected improvement of the intragranular response at the highest fluence 9.98 1017 neutrons/cm2. However, this fact is accompanied with a continuous suppression of the intergranular properties. We assume that this behavior is the result of the change of the nature of defect distribution at high fluence, when the uniform distribution of defects starts to develop space instabilities as a result of the subtle interplay of the in-cascade rate of interstitial loops production, cascade collapse of the vacancy loops, and the excess network bias.
We report the fabrication of composites made of La2/3Sr1/3MnO3 and two comb-type polysiloxane-bas... more We report the fabrication of composites made of La2/3Sr1/3MnO3 and two comb-type polysiloxane-based copolymers, polysiloxane-g-styrene and polysiloxane-g-(styrene-co-butyl-acrylate), in an attempt to improve the elastic properties of the polymer-based composites. The composites were obtained by the co-precipitation of a polymer solution mixed with the lanthanum manganite followed by sintering at appropriate temperatures. The rheological properties of the composites before as well as the magnetic and transport properties after sintering process are presented.
We investigated the effect of neutron irradiation on the electric and magnetic properties, includ... more We investigated the effect of neutron irradiation on the electric and magnetic properties, including the enhancement of the critical current density, of ceramic YBa2Cu3O7(LiF)x samples. The superconducting properties of the virgin samples reach the optimal values for x = 0.04. Up to the same x value, the neutron irradiation up to 5x10^17 neutrons/cm^2 enhances the superconducting response (critical temperature, transition width, etc) and double up the magnetic irreversibility. For x >= 0.08, all the superconducting properties are depressed whereas the increase of the irreversible magnetization is still present but less spectacular. The analysis of this behavior suggests a self-organization of the defects at low LiF content while for x >= 0.08 they are uniformly distributed within sample.
We investigated the transport properties of a series of composites made of La2/3Sr1/3MnO3 and dif... more We investigated the transport properties of a series of composites made of La2/3Sr1/3MnO3 and different copolymers. The temperature dependence of the electrical resistance of the samples is strongly dependent on the nature of the polymers. We found four types of temperature dependences of the electrical resistance: i) simple current dependence of resistivity for poly(methyl-methacrylate-co-styrene) copolymers, ii) single peaked characteristics for poly(acryl amide-co-vinyl acetate), iii) multipeaked dependence found in poly(methyl-methacrylate-co-butadiene) and star type polysiloxane-gstyrene, and iv) current independent characteristics visible in the samples made with linear polysiloxane-based composites.
ABSTRACT We present the fabrication and transport properties of a series of composites made of an... more ABSTRACT We present the fabrication and transport properties of a series of composites made of and acrylamide-based copolymers. The most important result is the very narrow transition, of only 27 K, displayed by the peak that appears around the metal-insulator transition of the composites made with poly(acrylamide-vinylacetate). Although the amount of polymer is rather low, different copolymers change drastically the electric transport characteristics.
IEEE Transactions on Applied Superconductivity, 2011
We present the fabrication and the superconducting properties of MgB2 ceramic samples doped with ... more We present the fabrication and the superconducting properties of MgB2 ceramic samples doped with carbon via preceramic polymers: linear and cyclic polysiloxane-co-styrene and linear polysiloxane-co-vinyl-ferrocene. The samples were produced using the spark plasma sintering technique. The use of polysiloxane copolymers was suggested by the appropriate content of carbon, silicon, and oxygen which are necessary to increase the upper critical field and to create pinning centers. The short processing time limits the diffusion length of the chemical elements from the polymer into the superconducting grains. Therefore, in addition to doping with carbon, the rest of the components create pinning centers along the polymeric chain, able to better pin the flux lines. The copolymerization allowed us to obtain both linear and cyclic copolymers as well as to control the content of chemical elements, including the presence of small amounts of iron oxides. The latter are responsible for magnetic pinning.
Lexical availability is an area of knowledge which aims at discovering those words which come imm... more Lexical availability is an area of knowledge which aims at discovering those words which come immediately and naturally to our mind when the conversation turns on a series of stimuli. Our research focuses on the available vocabulary of 280 students from Romanian-Spanish bilingual primary schools and high-schools. The participants in the lexical availability test were studying Spanish as a foreign language in primary schools Federico García Lorca and Uruguay, which offered intensive courses of 4 hours per week, and in bilingual high-schools Miguel de Cervantes, Resumen: La disponibilidad léxica es un campo que persigue conocer aquellas palabras que vienen de forma inmediata y natural a la mente cuando la conversación gira en torno a una serie de estímulos verbales. Nuestra investigación se centra en el vocabulario disponible de doscientos ochenta estudiantes de colegios e institutos bilingües rumano-españoles de Bucarest. El objetivo principal de este estudio es averiguar si los factores 'sexo' y 'haber visitado un país hispanohablante' inciden en el léxico disponible de español como lengua extranjera. El análisis cuantitativo y cualitativo de cada una de estas variables, junto con su correlación con el 'nivel de estudios', saca a la luz resultados destacados cuya explicación solo puede encontrarse en otras disciplinas, como son la sociolingüística o las ciencias cognitivas.
Abstracts, Resuscitation 2011 -Implementation / Resuscitation 82S1 (2011) S1-S34 S17 their wavefo... more Abstracts, Resuscitation 2011 -Implementation / Resuscitation 82S1 (2011) S1-S34 S17 their waveform, which in its turn can influence defibrillation thresholds (DT). The aim of the study was to compare DT in two different biphasic waveforms on high impedance porcine model.
We investigated the behaviour of YBa2Cu2O7-δ ceramics by multiharmonic ac-susceptibility. We have... more We investigated the behaviour of YBa2Cu2O7-δ ceramics by multiharmonic ac-susceptibility. We have found an unexpected improvement of the intragranular response at the highest fluence 9.98 1017 neutrons/cm2. However, this fact is accompanied with a continuous suppression of the intergranular properties. We assume that this behavior is the result of the change of the nature of defect distribution at high fluence, when the uniform distribution of defects starts to develop space instabilities as a result of the subtle interplay of the in-cascade rate of interstitial loops production, cascade collapse of the vacancy loops, and the excess network bias.
We report the fabrication of composites made of La2/3Sr1/3MnO3 and two comb-type polysiloxane-bas... more We report the fabrication of composites made of La2/3Sr1/3MnO3 and two comb-type polysiloxane-based copolymers, polysiloxane-g-styrene and polysiloxane-g-(styrene-co-butyl-acrylate), in an attempt to improve the elastic properties of the polymer-based composites. The composites were obtained by the co-precipitation of a polymer solution mixed with the lanthanum manganite followed by sintering at appropriate temperatures. The rheological properties of the composites before as well as the magnetic and transport properties after sintering process are presented.
We investigated the effect of neutron irradiation on the electric and magnetic properties, includ... more We investigated the effect of neutron irradiation on the electric and magnetic properties, including the enhancement of the critical current density, of ceramic YBa2Cu3O7(LiF)x samples. The superconducting properties of the virgin samples reach the optimal values for x = 0.04. Up to the same x value, the neutron irradiation up to 5x10^17 neutrons/cm^2 enhances the superconducting response (critical temperature, transition width, etc) and double up the magnetic irreversibility. For x >= 0.08, all the superconducting properties are depressed whereas the increase of the irreversible magnetization is still present but less spectacular. The analysis of this behavior suggests a self-organization of the defects at low LiF content while for x >= 0.08 they are uniformly distributed within sample.
We investigated the transport properties of a series of composites made of La2/3Sr1/3MnO3 and dif... more We investigated the transport properties of a series of composites made of La2/3Sr1/3MnO3 and different copolymers. The temperature dependence of the electrical resistance of the samples is strongly dependent on the nature of the polymers. We found four types of temperature dependences of the electrical resistance: i) simple current dependence of resistivity for poly(methyl-methacrylate-co-styrene) copolymers, ii) single peaked characteristics for poly(acryl amide-co-vinyl acetate), iii) multipeaked dependence found in poly(methyl-methacrylate-co-butadiene) and star type polysiloxane-gstyrene, and iv) current independent characteristics visible in the samples made with linear polysiloxane-based composites.
ABSTRACT We present the fabrication and transport properties of a series of composites made of an... more ABSTRACT We present the fabrication and transport properties of a series of composites made of and acrylamide-based copolymers. The most important result is the very narrow transition, of only 27 K, displayed by the peak that appears around the metal-insulator transition of the composites made with poly(acrylamide-vinylacetate). Although the amount of polymer is rather low, different copolymers change drastically the electric transport characteristics.
IEEE Transactions on Applied Superconductivity, 2011
We present the fabrication and the superconducting properties of MgB2 ceramic samples doped with ... more We present the fabrication and the superconducting properties of MgB2 ceramic samples doped with carbon via preceramic polymers: linear and cyclic polysiloxane-co-styrene and linear polysiloxane-co-vinyl-ferrocene. The samples were produced using the spark plasma sintering technique. The use of polysiloxane copolymers was suggested by the appropriate content of carbon, silicon, and oxygen which are necessary to increase the upper critical field and to create pinning centers. The short processing time limits the diffusion length of the chemical elements from the polymer into the superconducting grains. Therefore, in addition to doping with carbon, the rest of the components create pinning centers along the polymeric chain, able to better pin the flux lines. The copolymerization allowed us to obtain both linear and cyclic copolymers as well as to control the content of chemical elements, including the presence of small amounts of iron oxides. The latter are responsible for magnetic pinning.
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Papers by Elena Sandu