Diodo planar orgânico Schottky: construção e caracterização

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

A visão do usuário sobre o serviço público odontológico e a autopercepção em saúde bucal

Pós-graduação em Odontologia Preventiva e Social - FOA

Fundamentos psicológicos da pedagogia histórico-crítica e fundamentos pedagógicos da psicologia histórico cultural

This article presents the theoretical and methodological unity between the historical-critical pedagogy and cultural-historical psychology. It highlights, in addition to the membership of both theories to historical-dialectical materialism, the basic premises that point toward the affirmation of school education as a condition of humanization of individuals, as well as the transmission of historically systematized knowledge as one of the requirements for the achieving this purpose. In this direction, we aim to demonstrate that the historical-critical pedagogy contains, in its innerness, a solid psychological foundation, consistently built by a cultural-historical conception of man, society and educative nature that guides the relationship between them through the human vital activity, that is, through the work. It is in the core of those fundamentals that the alliance between this pedagogical theory and cultural-historical psychology is evident.

O regimento do corpo em Portugal no século XV

Pós-graduação em História - FCHS

Codificação de canais em sistemas de comunicação sem fio baseado em reticulados

Pós-graduação em Engenharia Elétrica - FEIS

Educação escolar e constituição do afetivo: algumas considerações a partir da psicologia histórico-cultural

Cultural-Historical Psychology alleges the thesis of social experience as the basis of human formation and points the affective-cognitive unity as the intermediate in subject relations with the knowledge on the development of psychological functions. This article presents some elements that indicate the constitution of affective processes from the relations the subject maintains with human objectifications. Part of the critics to the organismic and subjectivist thought that, both in Psychology and in Education, separates emotions from other functions of human consciousness – treating them as deterrents in the teaching and school learning processes – and signs the importance of (re) thinking the relations the subject establishes with reality, the role of knowledge and of the concrete conditions of life and education that produce the affective processes. It defends that thinking and feeling are psychological processes developed from history of appropriation and objectification of signs and instruments that each subject realizes and affirms in scholar education, and the intentional character of teaching – in the organizational and pedagogical practice – as determinant elements in the transformation of the ways of thinking and feeling.

Laços de família e segredos (sexuais) compartilhados: narrativa de história de vida de uma jovem dissidente em uma família homofóbica

This paper presents a non-heterosexual young lady s Narrative Life History. By presenting it, we aim to understanding how desire, (in)visibility and the processes of exclusion are articulated in relation to the experience of homoeroticism, especially within the family. By this, we are able to point out some homophobic aspects, modes of how the device of closet operates and how some expectations and demands exert pressures over a non-heterosexual member in the family. In this case study, the way her family lived her sexuality depended on a strong family ties, such as: the secret about sexuality. Such secret, according to our hypothesis, was produced and preserved by homophobia which served as the major aspect on the construction of gender and (dis)unity of the family. This work is part of a in progress doctoral thesis, sponsored by FAPESP Fundação para o Amparo à Pesquisa no Estado de São Paulo.

Narrativa e representação: uma leitura de Cidade de Deus

Pós-graduação em Estudos Literários - FCLAR

Votán-Zapata contra a Besta-fera: escritos do EZLN contra o capitalismo no México

Pós-graduação em Ciências Sociais - FFC

A note on the integral trace form in cyclotomic fields

Let m >= 3 be an integer, zeta(m) is an element of C a primitive mth root of unity, and K-m the cyclotomic field Q(zeta(m)). An explicit description of the integral trace form Tr-Km/Q(x (x) over bar)vertical bar Z[zeta(m)] where (x) over bar is the complex conjugate of x is presented. In the case where m is prime, a procedure for finding the minimum of the form subject to x being a nonzero element of a certain Z- module in Z[zeta(m)] is presented.

Fabricação e caracterização de diodo Schottky orgânico com arquitetura planar

Usually organic polymeric diodes are made with a semiconductor layer placed between two electrodes in a sandwich-like architecture, where the electrodes are deposited on the surfaces of a polymeric semiconductor film. This methodology leads to two main problems: i) the polymeric film top surface is rough and irregular, resulting in non-uniform electric field into the device; ii) during the deposition of metallic electrode in the top surface polymeric film, by thermal evaporation, occurs the diffusion of metal atoms into the polymeric film, changing the material electronic structure. Thus, the metal-semiconductor junction is not well defined, which is essential for the production of good quality Schottky diode, which exhibits ideality factor close to the unity and low turn-on voltage. In order to avoid these two problems, in the present research was proposed to manufacture an organic diode with the semiconductor polymeric layer deposited over bimetallic (gold and aluminum) interdigitated electrodes. The doping of the active layer was performed by immersing the device in hydrochloric acid solution with pH 2 during different times in order to promote different doping levels of the semiconductor polymer. Was verified that the proposed diode, which exhibits well-defined metal-semiconductor junction, operates as a Schottky diode, with good ideality factor, 10 ± 3, and low turn-on voltage, 1,2 ± 0,2 V, in comparison with conventional organic polymeric diodes. Contrasting with the ideality factor and turn-on voltage, the diode rectification ratio was obtained as 7, a value lower than the expected for a good organic diode. Was also showed that the diode characteristics were dependent on the semiconductor polymer doping level, and that the diode characteristics were optimized with doping promoted by immersion in the acid solution for times longer than 50 s. Furthermore, as was showed that the diodes properties are dependent on the semiconductor...

Propriedades ópticas e elétricas de materiais híbridos de sílica/orgânico à base de GPTS:TEOS preparados pelo método sol-gel

Fabrication of optoelectronic devices requires the employment of at least one transparent electrode. Usually, commercially transparent electrodes have been made by deposition of indium tin oxide (ITO) films by RF-Sputtering technique. These commercial electrodes have sheet resistance of about 100 Ω/sq and optical transmittance of 77% at the wavelength of 550 nm. The poly(3,4-ethylenedioxythiophene):polystyrene-sulfonate (PEDOT:PSS) is an alternative material to fabricate transparent electrodes due to its high conductivity (about 600 S/cm) and solubility in water. Soluble conductive materials exhibits advantages for processing of electrode layers, however there is a disadvantage during devices fabrication once materials with the same solvent of the electrode material cannot be coated one over the other. Alternatively, organic/Silica hybrid materials prepared by sol-gel process allow producing bulks and films with high chemical durability. In order to obtain transparent electrodes with high chemical durability, we introduced a blended material comprising the high UV-VIS transparency of organic/Silica sol-gel material and a high conductivity polymer PEDOT:PSS. The organic/Silica sol was obtained using two different molar concentrations (1:1 and 4:1), of tetraethylorthosilicate (TEOS) and 3-glycidoxypropyltrimethoxysilane (GPTS). Amounts of PEDOT:PSS solutions were added to the sol material, resulting in different weight fractions of sol and polymer. G:T/P:P were deposit onto glass substrates by spray-coating. In order to perform electrical characterization of the blended material, gold electrodes were thermally evaporated onto the films. The electrical characterization was performed using a Keithley 2410 source/meter unity and the optical characterization, using a Cary50 UV-Vis spectrophotometer. The absorption coefficient and electric conductivity of the different compositions blends, as function of the PEDOT:PSS concentration, were...

A new family of zero-current-switching PWM converters and a novel HPF-ZCS-PWM boost rectifier

A new family of direct current (DC) to DC converters based on a zero current switching pulse width modulated (ZCS-PWM) soft commutation cell is presented. This ZCS-PWM cell is consists of two transistors, two diodes, two inductors and one capacitor; and provides zero voltage turn-on to the diodes, a zero-current turn-on and a zero-current zero-voltage turn-off to the transistors. In addition, a new commutation cell in a new ZCS-PWM boost rectifier is developed, obtaining a structure with power factor near the unity, high efficiency at wide load range and low total harmonic distortion in the input current.