Resumen El procesamiento de soluciones es un método de bajo costo para preparar una variedad de películas delgadas orgánicas o inorgánicas. Para compuestos de óxidos metálicos, un procesamiento de solución de un compuesto organometálico se usa con frecuencia como solución precursora para ser recubierta por rotación, seguida de un tratamiento térmico para formar el óxido metálico. En este trabajo se obtienen polvos de óxido de vanadio a partir de una simple reacción ácido-base, y luego se dispersan en alcohol isopropílico para formar una solución para spin-coating. También se agregan diferentes cantidades de sal de cobalto junto con VOx en alcohol isopropílico para formar soluciones de VOx:Co2+. Después del tratamiento térmico a 200 °C, se obtienen películas delgadas transparentes. Se analizan las propiedades ópticas, estructurales, morfológicas y químicas. Se encontró que el compuesto VO2:Co2+ es amorfo y se obtiene con una relación atómica V:Co variada de 6.6:1-1.6:1. El material presenta una absorción óptica alrededor de 2.3 eV. Se observa una interesante morfología porosa interconectada cuando la relación atómica de V:Co es ~4.9:1. Se concluye que se pueden obtener películas delgadas amorfas porosas de VO2:Co2+ a partir del spin-coating a una baja temperatura de tratamiento utilizando una solución simple sin agente complejante.

Abstract Solution-processing is a low-cost solution method to prepare a variety of organic or inorganic thin films. For metal oxide compounds, a solution-processing solution of an organometallic compound is frequently used as a precursor to be spin coated, followed by a thermal annealing to form metal oxide. In this work, vanadium oxide powders are obtained from a simple acid-base reaction, and then they are dispersed in isopropyl alcohol to form a solution for spin-coating. Different amount of cobalt salt are also added together with VOx into isopropyl alcohol to form VOx:Co2+ solutions. After thermal annealing at 200 °C, continuous transparent thin films are obtained. Optical, structural, morphological and chemical binding energies of those films are analyzed. It is found that amorphous VO2:Co2+ compound is formed in those films with V:Co atomic ratios between 6.6:1 and 1.6:1. Optical absorption onsets of those films are around 2.3 eV. An interesting interconnected porous morphology is observed when the atomic ratio of V:Co is around 4.9:1. It is concluded that porous amorphous cobalt doped vanadium oxide thin films can be obtained from a spin-coating process at low annealing temperature from a simple solution without any complex agent.

Abstract CdTe thin films solar cells are currently produced using a layer sequence of glass/FTO/CdS/CdTe/metal contact (Cu/Ag), these films are deposited by two different techniques, chemical bath deposition (CBD) and close space vapour transport (CSVT). In order to reach reasonable conversion efficiencies, the device has to be thermally treated in a hydrated-CdCl2 atmosphere. This study was carried out using X-ray diffraction (XRD), photoluminescence, SEM-EDS, four probe method and SIMS profiling of CdTe. These analyses confirm the presence of hydrated CdCl2 and CdTe phases on CdTe surface and shown a good recrystallization morphology helping to the carriers mobility along the structure. Using the thermal treatment was possible to reduce the resistivity of CdTe thin film; it is a result to the Cl migration along the CdTe solar cell structure, reducing the defects between CdS and CdTe thin films. A strong CdTe thin film recrystallization was observed by the implementation of a hydrated-CdCl2 treatment doing to this a good candidate to CdTe solar cells process.

Abstract The fabrication and characterization of MOS capacitors with Hafnium Oxide as dielectric obtained at 150 ∘ C is described. The Hafnium Oxide thin films were obtained by spin-coating. The MOS capacitors were characterized employing measurements of capacitance vs. voltage, capacitance vs. frequency and current vs. voltage. The results demonstrate the feasibility of Hafnium Oxide film as a dielectric in electronic devices.

Resumen En este trabajo, se describe la fabricación y caracterización de capacitores MOS con óxido de hafnio como dieléctrico obtenido a 150 ∘ C. La obtención de películas delgadas de óxido de hafnio se realizó mediante spin-coating con un tratamiento térmico a 150 ∘ C. Los capacitores MOS fueron caracterizados empleando mediciones de capacitancia vs. voltaje, capacitancia vs. frecuencia y corriente eléctrica vs. voltaje. Los resultados demuestran la viabilidad de la película de óxido de hafnio como dieléctrico en dispositivos electrónicos.

A doped material can be obtained by substitution of one of its atoms with an impurity. In this work we propose four structural models which simulate a ZnO system doped with Eu and study the influence of the electron correlation in the system with the density of states (DOS). In particular, we observe that the lanthanide impurities exhibit peculiar optical and electronic properties due to the 4f subshell, which produce a Kondo-like resonance at the Fermi level.

Un material dopado se puede obtener al sustiuir uno de sus átomos por una impureza. En este trabajo se proponen cuatro modelos estructurales que simulan el material ZnO dopado con Eu y se analiza la influencia de la correlación electrónica mediante la densidad de estados (DOS) del sistema. En particular, las impurezas de lantánidos presentan propiedades ópticas y electrónicas peculiares debidas a los electrones en la capa 4f, los cuales generan una resonancia tipo Kondo en el nivel de Fermi.

This paper presents the development of an experimental bench for performing time-domain tests on synchronous machines at standstill. The test bench allows the collection of experimental data which can then be used in the parameter estimation of mathematical models of synchronous motors and generators. The system development is based on the LabVIEW programming language. It effortlessly allows the calibration of voltage and current sensors, the d-q magnetic axis positioning of the synchronous generator, and the spectral analysis from the collected data. In addition, the testing environment includes non-sophisticated instrumentation elements and a power amplifier. This experimental bench has a friendly user interface which guides the user throughout a defined methodology to allow the achievement of the different time domain tests on synchronous machines. A 7kVA, 220V, 60Hz synchronous generator was used to show the functionality and usefulness of the test bench in research and teaching electrical machine theory.

Este artículo presenta el desarrollo una plataforma para implementar pruebas experimentales en el dominio del tiempo a generadores síncronos en estado de reposo. La plataforma de pruebas permite la obtención de datos experimentales que pueden ser utilizados posteriormente para la estimación de parámetros tanto de los modelos matemáticos de motores como de generadores síncronos. El desarrollo del sistema se basa en el lenguaje de programación LabVIEW, permitiendo de manera sencilla la calibración de los sensores de corriente y de voltaje, el posicionamiento de la máquina síncrona en sus ejes d-q, así como el análisis espectral de las señales adquiridas. Además, el sistema cuenta con elementos de instrumentación no sofisticados y un amplificador de potencia. La plataforma incluye una interfaz amigable que guía al usuario a través de una metodología definida del desarrollo de las diferentes pruebas en el dominio del tiempo en generadores síncronos. Para demostrar la funcionalidad y utilidad de la plataforma de pruebas en la enseñanza e investigación de máquinas eléctricas se empleó un generador síncrono de 7kVA, 220V y 60Hz.

In this work synthesis of LTA zeolite and its ionic exchange with inorganic chemical salts were studied. Likewise experimental results are reported about LTA zeolite external surface area by using the t-plot method. Physicochemical characterization of this zeolite was carried out by XRD, SEM, IR and nitrogen adsorption (76 K) techniques. LTA zeolite was synthesized hydrothermally starting from a hydrogel mixture composed by NaOH, Na[Al(OH)4] and Na2SiO4 in stoichiometric amounts determined by its crystallization field. An ion exchange was carried out in LTA zeolite with AgNO3, KCl, CaCl2, CdCl2, ZnCl2, CuCl2 and MnCl2 (0.1 N for all of them). The LTA zeolite exchanged with bivalent cations showed the best properties to nitrogen adsorption. X-Ray diffraction showed good crystallization. Scanning electronic microscopy showed very well defined crystals existence. Textural studies of exchanged zeolite with chemical salts mentioned before by nitrogen adsorption method indicated that it is possible to obtain LTA zeolite substrates which contain high porosity. A great number of micropores of these zeolites are supermicropores (0.7 - 2 nm, pore-diameter). Microporosity studies by α s-plots of Sing was carry out and revealed that in LTA zeolite exchanged with CaCl2 exist ultramicropores and supermicropores in which the primary and secondary filling is carried out respectively

En este trabajo se reporta la síntesis de zeolita LTA y sus posteriores intercambios iónicos con distintas sales inorgánicas. De manera adicional se reportan datos experimentales sobre la estimación del área externa en zeolita LTA intercambiada usando el método t. La caracterización físico-química de estas zeolitas es abordada a través de métodos de Difracción de Rayos X (DRX), Microscopía Electrónica de Barrido (SEM), Espectroscopía de Infrarrojo (IR) y Adsorción de N2 a 76 K. La zeolita LTA fue sintetizada hidrotérmicamente partiendo de una mezcla compuesta por hidróxido de sodio, aluminato de sodio y silicato de sodio en las relaciones estequiométricas requeridas. Posteriormente se le realizó un intercambió iónico con nitrato de plata y sales en forma de cloruros de K, Ca, Cd, Zn, Cu, y Mn. La zeolita intercambiada con cationes bivalentes, presentó mejores propiedades para la adsorción de nitrógeno. Los espectros de rayos X de la zeolita matriz y de aquella intercambiada mostraron buena cristalinidad. La microscopía electrónica de barrido mostró la presencia de un gran número de cristales definidos y biselados. El estudio de caracterización de textura de la zeolita intercambiada con las distintas sales mencionadas mediante la adsorción de nitrógeno a 76 K mostró que es posible obtener substratos de zeolita LTA que desarrollen altas porosidades. La mayoría de los microporos de estos materiales son supermicroporos (huecos entre 0.7 y 2 nm). El valor de la microporosidad determinada por el método α de Sing para la muestra intercambiada con Ca, revela que los microporos contenidos en la zeolita incluyen ultramicroporos y supermicroporos, en los cuales se lleva a cabo el llenado primario y secundario respectivamente.

Vasoplegia is a frequent complication in post-operative heart surgery and determines a significant increase in morbidity-mortality. When vasoplegia persists in spite of optimized fluid therapy with the use of Swan-Ganz catheter, we have a safe, effective and economical alternative, methylene blue. We present the case of a patient who developed vasoplegia refractory to treatment and shock in the scheduled post-operative period of myocardial revascularization. The use of a single dose of methylene blue resolved the hemodynamic instability and allowed for total discontinuation of vasoactive drugs. Thus, we present this new indication of methylene blue, still not approved by the corresponding bodies, for which no national publications have been found and its clinical management and the absence of adverse effects after its use.

La vasoplejía es una complicación frecuente en el postoperatorio de cirugía cardíaca y determina un importante aumento en la morbi-mortalidad. Cuando a pesar de una fluidoterapia optimizada con el uso del catéter Swan-Ganz y una perfusión de noradrenalina persiste la vasoplejía, disponemos de una alternativa segura, eficaz y económica, el azul de metileno. Presentamos el caso de un paciente que en el postoperatorio programado de revascularización miocárdica desarrolló una vasoplejía refractaria al tratamiento y shock. La utilización de una sola dosis de azul de metileno resolvió la inestabilidad hemodinámica y permitió la suspensión total de los fármacos vasoactivos. Por tanto, se expone esta novedosa indicación del azul de metileno, aún no aprobada por los organismos correspondientes, de la que no hemos encontrado publicaciones nacionales, así como su manejo clínico y la ausencia de efectos adversos tras su utilización.

Breeding for high and low hypothermic responses to systemic administration of a serotonin1A (5-HT1A) receptor agonist (8-hydroxy-2-(di-n-propylamino)tetralin, 8-OH-DPAT) has resulted in high DPAT-sensitive (HDS) and low DPAT-sensitive (LDS) lines of rats, respectively. These lines also differ in several behavioral measures associated with stress. In the present microdialysis study we observed that basal 5-HT concentrations in the prefrontal cortex and dorsal hippocampus did not differ significantly between HDS and LDS rats. Thus, behavioral differences between the HDS and LDS lines might not be attributed to differences in basal 5-HT release. However, both lines had lower basal levels of 5-HT release than their randomly bred control group (random DPAT-sensitive, RDS) in the prefrontal cortex (mean ± SEM, pg/20 µl, was 3.0 ± 0.4 for LDS, 3.8 ± 0.3 for HDS and 6.4 ± 0.6 for RDS; F(2,59) = 5.8, P<0.005). The administration of (±)-fenfluramine (10 mg/kg) induced a greater increase in hippocampal 5-HT levels in HDS rats (500%) as compared with LDS (248%) or RDS (243%) rats (P<0.0001). There were no significant differences in the prefrontal cortex among lines, with a fenfluramine-induced 5-HT increase of about 900% in the three groups. This differential response to fenfluramine may be due to functional alterations of hippocampal 5-HT reuptake sites in the HDS line.

Para avaliar aspectos qualitativos e nutricionais da figueira em relação a seis níveis de irrigação e de nitrogênio, desenvolveu-se um experimento em blocos ao acaso, com parcelas subdivididas e com quatro repetições, em Ilha Solteira,SP. Os resultados mostraram que em quatro datas de colheita, apenas a primeira análise (2 de janeiro de 91) mostrou influência da fertilização nitrogenada sobre os sólidos solúveis (brix) dos frutos. Não houve efeito significativo dos tratamentos sobre a relação polpa/casca, nas quatro colheitas. Com relação à concentração de macronutrientes nas folhas na época de florescimento, o suprimento de água influenciou as concentrações de N, P e Ca e a aplicação de nitrogênio influenciou apenas a concentração de Ca. Para uma produção média de 10 t.ha-1 de frutos maduros e de 1,3 t.ha-1 de frutos verdes, observou-se uma exportação de aproximadamente 65 kg.ha-1 de N; 10 kg.ha-1 de P2O5 ; 44 kg.ha-1 de K2O; 35 kg.ha-1 de Ca e 9 kg.ha-1 de Mg.

In order to evaluate qualitative and nutritional aspects of fig-trees with respect to six irrigation and six nitrogen levels, at Ilha Solteira, SP, Brazil, an experiment was carried out in randomized blocks, with subdivided plots, and four replications. Results showed that in four dates during harvest, only the first analysis (January 2, 1991) showed influence of nitrogen fertilization on fruit soluble solids (brix). There was no significant effect of treatments on pulp/peel relation for the four harvestings. In relation to leaf macronutrient concentration at flowering, water supply influenced N, P and Ca concentrations, and nitrogen influenced only Ca concentration. For an average of 10 t.ha-1 of mature fruit and 1.3 t.ha-1 of immature fruit production, there was a nutrient export of about 65 kg.ha-1 of N; 10 kg.ha-1 of P2O5; 44 kg.ha-1 of K2O; 35 kg.ha-1 of Ca and 9 kg.ha-1 of Mg.

Com o objetivo de avaliar a resposta da cultura da figueira (safra 91/92) à aplicação de lâminas de irrigação e adubação nitrogenada realizou-se um experimento com seis lâminas de irrigação (O, 25, 50, 75,100 e 125% da evaporação do Tanque Classe A) e seis níveis de nitrogênio (0,150,300,450,600 e 750 g/planta), instalado de acordo com um delineamento de blocos casualizados, em um esquema de parcelas sub-divididas, com quatro repetições. Com base na análise estatística realizada, verificou-se efeito significativo da irrigação sobre a produtividade de frutos maduros, produtividade total, comprimento de ramos e altura e diâmetro de frutos maduros. A adubação nitrogenada mostrou efeito significativo sobre a produtividade de frutos maduros e comprimento de ramos.

The study had the purpose of evaluating the effects of irrigation and nitrogen fertilization levels upon fig-tree orchards (harvest 1991/1992). A randomized split-plot block design was installed with six irrigation levels (0, 25, 50, 75,100 and 125% of Class A Pan Evaporation) and six nitrogen levels (0, 150, 300, 450, 600 and 750 g/plant), with four repetitions. According to the statistical analysis, significant effects of water supply were verified on ripe fruit harvest, total productivity, branch lenght and ripe fruit heigth and diameter. Nitrogen fertilization effects on ripe fruit harvest and branch lenght were also detected.

O presente trabalho foi conduzido com o objetivo de se estudar 3 doses de N e 3 doses de K2O, combinadas entre si e aplicadas em cobertura aos 15, 30 e 45 dias após a emergência das plântulas, na eficiência do uso da água e na qualidade de frutos de melão. Utilizou-se um Podzólico Vermelho Escuro, eutrófíco, textura média/argilosa, do município de Ilha Solteira(SP). O experimento foi implantado no ano de 1991 fazendo-se uso dos cultivares Valenciano Amarelo e Eldorado 300, em espaçamento de 2,0m entre linhas e 0,75m entre covas. A cultura foi conduzida sem capação e desbrota e os tratamentos fítossanitários procedidos de acordo com a necessidade. Pelos resultados obtidos verificou-se que o N ou o K2O influenciaram alguns parâmetros no cultivar Eldorado 300: peso da casca, peso de sementes com mucilagem e acidez titulável, além do rendimento de polpa no cultivar Valenciano Amarelo.

The present work was developed with the objective of studying 3 combined doses of N and K2O, applied as cover dressings within 15, 30 and 45 days after seedling emergence, in the water efficience use and fruit quality of muskmelons grown on a Dark Red Podzolic soil. The experiment was carried in Ilha Solteira, Sao Paulo State, Brazil. The experiment was carried out in 1991 with the Valenciano Amarelo and Eldorado 300 cultivars, in a 2.0 x 0.75m spacing. The results showed that N and K2O influenced some parameters of the Eldorado 300 cultivar: peel weight, seed weight and acidity; pulp yield in Valenciano Amarelo cultivar.