1,084 research outputs found
Limits on the use of cobalt sulfide as anode of p-type dye-sensitized solar cells
Thin films of cobalt sulfide (CoS) of thickness l < 10m have been employed as anodes of p-type dye-sensitized solar cells (p-DSCs) when P1-sensitized nickel oxide (NiO) was the photoactive cathode and /I - constituted the redox mediator. In the role of counter electrode for p-DSCs, CoS was preferred over traditional platinized fluorine-doped indium oxide (Pt-FTO) due to the lower cost of the starting materials (Co salts) and the easier procedure of deposition onto large area substrates. The latter process was carried out via direct precipitation of CoS from aqueous solutions. The photoconversion efficiency (η) of the corresponding device was 0.07%. This value is about 35% less than the efficiency that is obtained with the analogous p-DSC employing the Pt-FTO anode (η = 0.11). Unlike p-DSCs based on Pt-FTO anodes, the photoelectrochemical cells employing CoS electrodes showed that this anodic material was not able to sustain the photocurrent densities generated by P1-sensitized NiO at a given photopotential. Illumination of the p-DSCs with CoS anodes and P1-sensitized NiO cathodes actually induced the reverse bias of the photoelectrochemical cell with CoS behaving like a p-type semiconductor with no degeneracy. © 2017 IOP Publishing Ltd
Perceived barriers for treatment of chronic heart failure in general practice; are they affecting performance?
Rashba spin-orbit coupling and spin relaxation in silicon quantum wells
Silicon is a leading candidate material for spin-based devices, and
two-dimensional electron gases (2DEGs) formed in silicon heterostructures have
been proposed for both spin transport and quantum dot quantum computing
applications. The key parameter for these applications is the spin relaxation
time. Here we apply the theory of D'yakonov and Perel' (DP) to calculate the
electron spin resonance linewidth of a silicon 2DEG due to structural inversion
asymmetry for arbitrary static magnetic field direction at low temperatures. We
estimate the Rashba spin-orbit coupling coefficient in silicon quantum wells
and find the and times of the spins from this mechanism as a
function of momentum scattering time, magnetic field, and device-specific
parameters. We obtain agreement with existing data for the angular dependence
of the relaxation times and show that the magnitudes are consistent with the DP
mechanism. We suggest how to increase the relaxation times by appropriate
device design.Comment: Extended derivations and info, fixed typos and refs, updated figs and
data. Worth a re-downloa
The effect of temperature on mobility of Angiostrongylus costaricensis third stage larvae
Análise contrastiva de produções em português de estudantes hispanofalantes: questões de acentuação
Anais e artigos do 28º Fórum Acadêmico de Letras, realizado nos dias 23 a 25 de agosto de 2017 na Universidade Federal da Integração Latino-Americana (Unila) e Universidade Estadual do Oeste do Paraná (Unioeste) com tema: A pesquisa nos cursos de letras em contexto de línguas e culturas em contato.A insuficiência de estudos contrastivos que contemplem as dificuldades de uso da
acentuação em produções de universitários hispanofalantes aprendizes de português, impulsionou a
realização deste trabalho. Com base nas regras de acentuação gráfica presentes na “Moderna
Gramática Portuguesa” (Bechara, 2009) e na “Gramática Contrastiva del Español para Brasileños”
(Fernández e Moreno, 2007) foi realizada a análise e descrição de erros de acentuação nas produções
em português de estudantes hispanofalantes do nível básico. Em tal contexto, as dificuldades no
emprego da acentuação do português brasileiro ocorrem, principalmente, devido a uma interferência
das regras da língua materna bem como da distinção entre vogais orais e nasais, ocasionando uma
omissão ou acréscimo de acento equivocado. Visando minimizar a recorrência de tais erros por parte
dos estudantes hispanofalantes em suas produções em português, são sugeridas propostas de
abordagens para que o estudante por meio do contraste das regras de acentuação do português e do
espanhol consiga ter um melhor desempenh
Please Stand and be Recognized: Examining Individuals’ Attitudes and Behaviors Regarding Colleges and Universities that Honor Veterans
Reply: The classification of p53 immunohistochemical staining results and patient outcome in ovarian cancer
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