6,844 research outputs found
Effects of an extra gauge boson on the top quark decay
The effects of an extra gauge boson with family nonuniversal fermion
couplings on the rare top quark decay gamma10^{-8}m_{Z'}=500Z'B(t --> c
\gamma)\sim 10^{-6}m_{Z'}=1$ TeV.Comment: New paragraphs included to clarify our results, conclusion remains
unchange
Perspectivas da bubalinocultura no Baixo Madeira no estado de Rondonia.
Estudo preliminar visando suprir deficiencia de carne e leite dos moradores das margens do Rio Madeira. Envolve aspectos relativos a bubalinocultura, operacoes que formam o sistema, producao de leite, instalacoes, comercializacao e sugestoes para o fomento da bubalinocultura.bitstream/item/55121/1/Circ.tecn-03-0001.pd
Dependence of Ga-doped ZnO thin film properties on different sputtering process parameters: Substrate temperature, sputtering pressure and bias voltage
This paper reports on the effects of different sputtering deposition process parameters (substrate temperature,
sputtering pressure and bias voltage) on the electrical, optical, structural and morphological properties of
gallium-doped ZnO (ZnO:Ga) of ~1 μm thick. These highly transparent and conductive films were deposited
on glass surfaces by d.c. pulsed magnetron sputtering from a GZO (ZnO(95.5):Ga2O3(4.5)) ceramic target in an
argon atmosphere. X-ray diffraction experiments show that all films have a hexagonal wurtzite structure with
the [001] preferred crystallographic direction, and themorphology of the films (obtained fromscanning electron
microscope analysis) is sensitive to the process parameters. All ZnO:Ga films have an average transmittance
above 80% in the visible region, and the lowest electrical resistivity of 3.03 × 10−4 Ω·cm was achieved for the
sample submitted to the lowest bias voltage (−40 V), which corresponds to a carrier concentration and a carrier
mobility of 6.99 × 1020 cm−3 and 29.49 cm2 V−1 s−1, respectively. A high substrate temperature, high sputtering
pressure and lownegative bias voltage (within the range of studied parameters) proved to be very promising on
obtaining optimized ZnO:Ga films, ensuring suitable properties for application as transparent electrodes in photovoltaic
cells.The authors acknowledge the funding from the Portuguese Innovation Agency (AdI), project reference WinDSC-21539, co-funded by FEDER/POFC
Cardiac Arrest in the Pediatric Population
Apresenta-se o caso clÃnico de uma criança de 10 anos com paragem cardÃaca em repouso que foi reanimada, com sucesso. A investigação etiológica do acidente mostrou uma Cardiomiopatia Hipertrófica (CMH). Foi colocado um Cardiodesfibrilhador Implantável (CDI) para profilaxia secundária da Morte Súbita (MS). A Morte Súbita em idade pediátrica é uma situação rara, de muito mau prognóstico (sobrevida sem sequelas inferior a 5%) e com um impacto social significativo. A Cardiomiopatia Hipertrófica é uma causa conhecida de Morte Súbita, com possibilidade de prevenção. O caso apresentado serve para levantar questões sobre a necessidade e forma de estratégias para prevenir a MS de etiologica cardÃaca em idade pediátrica
Characterization of microstructured multiwalled carbon nanotube/polydimethylsiloxane composites for piezoresistive sensing applications
Technological advancements in the field of flexible and printed electronics are creating a need for large-area sensors that can be embedded over different types of surfaces. Such sensors can be used to monitor physical signals over flexible, curved, or soft devices. Hence, it is herein proposed, a formulation to produce piezoresistive multiwalled carbon nanotube/polydimethylsiloxane (MWCNT/PDMS) composites with tunable electric properties for pressure sensing purposes. The composite is obtained through few manufacturing steps, avoiding the use of hazardous solvents. Different weight percentages of MWCNT dispersed in PDMS are evaluated and the results evidence that using 3.0 wt% of infill is sufficient to obtain highly sensitive sensors. To enhance the dispersion of the MWCNT and add microstructure to the composite, a system composed of a surfactant and foaming agent is used. Finally, pressure sensing units and arrays are printed and tested. The sensors present fast response, low hysteresis, repeatability, and a sensing range of 0–160 kPa. The composite is more sensitive to lower pressure and a maximum sensitivity of 8.0% kPa−1 is achieved for porous composites at pressure <10 kPa. Thanks to these characteristics, the sensors are successfully used in the development of a pressure sensing array and heartbeat sensor for proof of concept.This work has been supported by NORTE-06-3559-FSE-000018, integrated in the invitation NORTE-59-2018-41, aiming the Hiring of Highly Qualified Human Resources, co-financed by the Regional Operational Programme of the North 2020, thematic area of Competitiveness and Employment, through the European Social Fund (ESF), and by the scope of projects with references UIDB/05256/2020 and UIDP/05256/2020, financed by FCT—Fundação para a Ciência e Tecnologia, Portugal
Photocatalytic thin films coupled with polymeric microcapsules for the controlled-release of volatile agents upon solar activation
This work reports on the application of solar-activated photocatalytic thin films that
allow the controlled-release of volatile agents (e.g., insecticides, repellents) from the interior of
adsorbed polymeric microcapsules. In order to standardize the tests,a quantification of the
inherent controlled-release of a particular volatile agent is determined by gas chromatography
coupled to mass spectroscopy, so that an application can be offered to a wide range of supports
from various industrial sectors, such as in textiles (clothing, curtains, mosquito nets). This
technology takes advantage of the established photocatalytic property of titanium dioxide
(TiO2) for the use as an active surface/site to promote the controlled-release of a specific vapor
(volatile agentfrom within the aforementioned microcapsules.Portuguese FCT COMPETE scientific
programs, with references NANO/NTec-CA/0046/2007 and PTDC/CTM-NAN/119979/201
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