ABSTRACT
The photosensitivity, responsivity, and signal-to-noise ratio of organic phototransistors depend on the timing characteristics of light pulses. However, in the literature, such figures of merit (FoM) are typically extracted in stationary conditions, very often from IV curves taken under constant light exposure. In this work, we studied the most relevant FoM of a DNTT-based organic phototransistor as a function of the timing parameters of light pulses, to assess the device suitability for real-time applications. The dynamic response to light pulse bursts at ~470 nm (close to the DNTT absorption peak) was characterized at different irradiances under various working conditions, such as pulse width and duty cycle. Several bias voltages were explored to allow for a trade-off to be made between operating points. Amplitude distortion in response to light pulse bursts was also addressed.
ABSTRACT
Understanding radiation damage in materials has been a topic of great interest for many years and in multiple scientific sectors [...].
ABSTRACT
This paper describes the scintillation features and the radiation damage in polyethylene naphthalate 100 µm-thick scintillators irradiated with an 11 MeV proton beam and with a 1 MeV electron beam at doses up to 15 and 85 Mrad, respectively. The scintillator emission spectrum, optical transmission, light yield loss, and scintillation pulse decay times were investigated before and after the irradiation. A deep blue emission spectrum peaked at 422 nm, and fast and slow scintillation decay time constants of the order of 1-2 ns and 25-30 nm, respectively, were measured. After irradiation, transmittance showed a loss of transparency for wavelengths between 380 and 420 nm, and a light yield reduction of ~40% was measured at the maximum dose of 85 Mrad.
ABSTRACT
Nanostructured films of carbon and TiO2 nanoparticles have been produced by means of a simple two-step procedure based on flame synthesis and thermophoretic deposition. At first, a granular carbon film is produced on silicon substrates by the self-assembling of thermophoretically sampled carbon nanoparticles (CNPs) with diameters of the order of 15 nm. Then, the composite film is obtained by the subsequent thermophoretic deposition of smaller TiO2 nanoparticles (diameters of the order of 2.5 nm), which deposit on the surface and intercalate between the carbon grains by diffusion within the pores. A bipolar resistive switching behavior is observed in the composite film of CNP-TiO2. A pinched hysteresis loop is measured with SET and RESET between low resistance and high resistance states occurring for the electric field of 1.35 × 104 V/cm and 1.5 × 104 V/cm, respectively. CNP-TiO2 film produced by flame synthesis is initially in the low resistive state and it does not require an electroforming step. The resistance switching phenomenon is attributed to the formation/rupture of conductive filaments through space charge mechanism in the TiO2 nanoparticles, which facilitate/hinder the electrical conduction between carbon grains. Our findings demonstrate that films made of flame-formed CNP-TiO2 nanoparticles are promising candidates for resistive switching components.
ABSTRACT
O presente trabalho foi realizado entre dezembro de 2003 e janeiro de 2004. Teve como objetivo avaliar a ocorrência de teníase nessa população. Participaram do estudo 628 pessoas, dessas, 16 (2,5%) eram portadores de teníase. Praticamente a metade dos casos de teníase ocorreram em indivíduos na faixa etária entre os 30 a 49 anos (49,9%). Ocorreu associação entre existência dehortas e adubação, com os casos de teníase (p < 0,001). O consumo de carne de porco mal passada, também apresentou significância estatística (p = 0,003). A presença de sintomas estava associada aos casos com teníase (p = 0,004). Constatou-se ainda, que as pessoasque apresentaram teníase tinham maior chance de possuir outras enteroparasitoses (p = 0,038). O maior problema do bairro é a falta de infra-estrutura sanitária, possibilitando a exposição das pessoas e dos animais, ao esgoto a céu aberto, favorecendo a manutenção do complexo teníase/cisticercose. Desta forma, para interromper essa cadeia de transmissão faz-se necessária à melhoria da infra-estrutura sanitária e intensificação das ações preventivas e educativas em saúde pública.
The present study was done from december, 2003 to january, 2004. The main objective of this research was to evaluate the occurrence of taeniasis among its population. 628 people took part in the study, being 16 (2,5%) of the participants carriers of taeniasis. Almost half of the cases of teniasis were found among individuals around the age of 30 to 49 years (49.9%). A correlation between the existence of vegetable gardens and adubation and the cases of taeniasis was found (p=0.001). The consumption of raw pork meat was found to be statistically significant (p=0.003).The symptons were associated with cases of taeniasis (p = 0.004). It was also found that those who had taeniasis had a higher chance of having other enteroparasites (p=0.038). The most important problem in the neighborhood is the lack of sanitary infrastructure, forcing people and animals to the open contact with landfills and sewage contamination, and therefore favouring the maintenance of the complex taeniasis/cysticercose. In order to end this transmission chain, it is necessary that a sanitary infra-structure is implemented and that preventive and educational actions in public health be intensified.
