Growth study of indium-catalyzed silicon nanowires by plasma enhanced chemical vapor deposition

Indium was used as a catalyst for the synthesis of silicon nanowires in a plasma enhanced chemical vapor deposition reactor. In order to foster the catalytic activity of indium, the indium droplets had to be exposed to a hydrogen plasma prior to nanowire growth in a silane plasma. The structure of the nanowires was investigated as a function of the growth conditions by electron microscopy and Raman spectroscopy. The nanowires were found to crystallize along the , or growth direction. When growing on the and directions, they revealed a similar crystal quality and the presence of a high density of twins along the {111} planes. The high density and periodicity of these twins lead to the formation of hexagonal domains inside the cubic structure. The corresponding Raman signature was found to be a peak at 495 cm−1, in agreement with previous studies. Finally, electron energy loss spectroscopy indicates an occasional migration of indium during growt

Optical study of the band structure of wurtzite GaP nanowires

We investigated the optical properties of wurtzite (WZ) GaP nanowires by performing photoluminescence (PL) and time-resolved PL measurements in the temperature range from 4 K to 300 K, together with atom probe tomography to identify residual impurities in the nanowires. At low temperature, the WZ GaP luminescence shows donor-acceptor pair emission at 2.115 eV and 2.088 eV, and Burstein-Moss band-filling continuum between 2.180 and 2.253 eV, resulting in a direct band gap above 2.170 eV. Sharp exciton α-β-γ lines are observed at 2.140-2.164-2.252 eV, respectively, showing clear differences in lifetime, presence of phonon replicas, and temperature- dependence. The excitonic nature of those peaks is critically discussed, leading to a direct band gap o

Postharvest quality of "Rama Forte" persimmon stored at passive modified atmosphere packaging.

"Rama Forte" persimmon presents a short shelf life after harvesting and during commercialization. The objective of this work was evaluate quality of "Rama Forte" persimmon conditioned under modified atmosphere and kept under refrigeration.Sessão de Pôste

The role of sub-national actors in coordinative Europeanisation: insights from the digitalisation of asylum services

Coordinative Europeanisation is a powerful frame to explain the rapid response of EU institutions in times of permanent emergency. So far, though, little is known about sub-national actors’ role in this process. Moving away from a state-centric approach, this article investigates the role of sub-national actors through the case study of the digital provision of services to asylum seekers. Given the field’s high salience and state-centric nature, this article elucidates the critical role of European sub-national actors, particularly at the municipality level, to accelerate the digital provision of services to refugees. Comparing 3 European cities (Paris, Palermo and Malaga), we argue that sub-national actors can play a role in coordinative Europeanisation and that 2 main mechanisms may enable it. In the cases observed, discursive coordination around humanitarian duty facilitated the emergence of similar digital solutions across countries. Subsequently, horizontal and vertical networking was used by sub-national actors to legitimise their actions and enhance their anchoring in processes of coordinative EuropeanisationHistory and International Studies 1900-presen

Ebf factors and MyoD cooperate to regulate muscle relaxation via Atp2a1

Jin, Saihong et al.Myogenic regulatory factors such as MyoD and Myf5 lie at the core of vertebrate muscle differentiation. However, E-boxes, the cognate binding sites for these transcription factors, are not restricted to the promoters/enhancers of muscle cell-specific genes. Thus, the specificity in myogenic transcription is poorly defined. Here we describe the transcription factor Ebf3 as a new determinant of muscle cell-specific transcription. In the absence of Ebf3 the lung does not unfold at birth, resulting in respiratory failure and perinatal death. This is due to a hypercontractile diaphragm with impaired Ca2+ efflux-related muscle functions. Expression of the Ca2+ pump Serca1 (Atp2a1) is downregulated in the absence of Ebf3, and its transgenic expression rescues this phenotype. Ebf3 binds directly to the promoter of Atp2a1 and synergises with MyoD in the induction of Atp2a1. In skeletal muscle, the homologous family member Ebf1 is strongly expressed and together with MyoD induces Atp2a1. Thus, Ebf3 is a new regulator of terminal muscle differentiation in the diaphragm, and Ebf factors cooperate with MyoD in the induction of muscle-specific genes. © 2014 Macmillan Publishers Limited.This work was supported by grants from the German Research Foundation (DFG, TRR54; FOR1586; FOR2033) and by a stipend of the Max Planck SocietyPeer Reviewe

Study of the temperature distribution in Si nanowires under microscopic laser beam excitation

The use of laser beams as excitation sources for the characterization of semiconductor nanowires (NWs) is largely extended. Raman spectroscopy and photoluminescence (PL) are currently applied to the study of NWs. However, NWs are systems with poor thermal conductivity and poor heat dissipation, which result in unintentional heating under the excitation with a focused laser beam with microscopic size, as those usually used in microRaman and microPL experiments. On the other hand, the NWs have subwavelength diameter, which changes the optical absorption with respect to the absorption in bulk materials. Furthermore, the NW diameter is smaller than the laser beam spot, which means that the optical power absorbed by the NW depends on its position inside the laser beam spot. A detailed analysis of the interaction between a microscopic focused laser beam and semiconductor NWs is necessary for the understanding of the experiments involving laser beam excitation of NWs. We present in this work a numerical analysis of the thermal transport in Si NWs, where the heat source is the laser energy locally absorbed by the NW. This analysis takes account of the optical absorption, the thermal conductivity, the dimensions, diameter and length of the NWs, and the immersion medium. Both free standing and heat-sunk NWs are considered. Also, the temperature distribution in ensembles of NWs is discussed. This analysis intends to constitute a tool for the understanding of the thermal phenomena induced by laser beams in semiconductor NWs

Avaliação pós-colheita de caquis "Rama Forte" acondicionados sob diferentes embalagens de atmosfera modificada passiva.

Caquis ?Rama Forte? apresentam curta vida útil após a colheita e durante a comercialização. Na bibliografia, encontram-se relatos de escurecimento na epiderme da variedade, quando acondicionados em refrigeração, impossibilitando sua comercialização. A atmosfera modificada, de embalagens passivas, ocorre por consequência da respiração dos frutos, vegetais ou atividade metabólica de microrganismos associados a alimentos

Avaliação de caquis "Rama Forte" destanizados após armazenamento sob atmosfera modificada passiva.

A cultivar Rama Forte tem sabor agradável, mas possui adstringência e necessita de destanização antes da sua comercialização. O armazenamento refrigerado é a principal forma de conservação empregada pelos pequenos produtores da fruta e, aliada a essa técnica, pode-se empregar a atmosfera modificada passiva (AMP)

Comportamento de caquis "Rama Forte" destanizados após armazenamento sob atmosfera modificada passiva.

A produção de caqui no Rio Grande do Sul destina-se quase que exclusivamente ao consumo in natura e a comercialização ocorre no período de safra, dado seu curto período de armazenamento