Spin-polarized nearly-free electron channels on the Ca2_{2}N electrenes

Two-dimensional (2D) materials combined with the presence of surface nearly-free electrons (NFE) have been considered quite interesting platforms to be exploited for the development of 2D electronic devices. Further incorporation of foreign elements adds a new degree of freedom to engineer the electronic as well as the magnetic properties of 2D materials. Here we have performed an ab-initio study of Ca$_{2}$N, electrenes fully (i.e., both sides) adsorbed by hydrogen (H/Ca$_{2}$N/H) and fluorine (F/Ca$_{2}$N/F) atoms. The NFE states are suppressed in these systems, followed by the appearance of a net magnetic moment localized in the nitrogen atoms intercalated by the hydrogenated or fluorinated calcium layers. In the sequence, we have proposed lateral heterostructures combining the H/Ca$_{2}$N/H or F/Ca$_{2}$N/F regions with pristine Ca$_{2}$N, electrenes [(Ca$_{2}$N)(X/Ca$_{2}$N/X), with X=H or F]. We found that the magnetic moment of the hydrogenated or fluorinated regions promotes the emergence of spin-polarized NFE states confined along the pristine (Ca$_{2}$N) stripes. Further electronic transport calculations reveal that the (X/Ca$_{2}$N/X) regions act as spin-dependent scattering centers, spin-filters. We believe that these findings make an important contribution to the development of spintronic devices based on 2D electrides.Comment: 6 pages, 5 figure

Bilayer graphene dual-gate nanodevice: An ab initio simulation

We study the electronic transport properties of a dual-gated bilayer graphene nanodevice via first principles calculations. We investigate the electric current as a function of gate length and temperature. Under the action of an external electrical field we show that even for gate lengths up 100 Ang., a non zero current is exhibited. The results can be explained by the presence of a tunneling regime due the remanescent states in the gap. We also discuss the conditions to reach the charge neutrality point in a system free of defects and extrinsic carrier doping

Comportamento da oviposição de Cleruchoides noackae (Hymenoptera: Mymaridae), parasitoide de ovos de Thaumastocoris peregrinus (Hemiptera: Thaumastocoridae).

Resumo

Physical-chemical characterization of integral grape juices elaborated with cv. Concord in the Sub-middle São Francisco Valley.

The objective of this study was to evaluate the physical-chemical characteristics of grape juices elaborated with cv. Concord, grafted onto IAC 572, cultivated on pergola, and irrigated by drip, planted a partner enterprise, in one season in the São Francisco Valley

Physical-chemical characterization of integral grape juices elaborated with cv. Concord in the Sub-middle São Francisco Valley.

The objective of this study was to evaluate the physical-chemical characteristics of grape juices elaborated with cv. Concord, grafted onto IAC 572, cultivated on pergola, and irrigated by drip, planted a partner enterprise, in one season in the São Francisco Valley

Controlled stacking of graphene monolayer saturable absorbers for ultrashort pulse generation in erbium-doped fiber lasers

FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPStacked chemical-vapour deposited (CVD) graphene monolayer samples were fabricated and applied as saturable absorbers in erbium-doped fiber laser (EDFL). Transient absorption experiments show that at the saturation absorption regime, and regardless the number of stacked layers (from 1 to 5 layers), samples present 1 ps recovery time. Pulses with duration from 0.60 to 1.17 ps were generated in an EDFL, depending on the number of graphene layers (i.e., the linear optical absorption) used. The results show that it is possible to increase the linear optical absorption of a graphene stacking without affecting its nonlinear optical behavior and ultrafast response time. Therefore, by stacking individual CVDmonolayer graphene samples it is possible to control the optical properties in graphene-based EDFLs and simultaneously tune their ultra-short pulse generation.7725282537FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP2010/19085-82012/07678-02012/50259-82013/16911-

Influência da carga pendente, do espaçamento e de fatores climáticos no desenvolvimento da ferrugem do cafeeiro.

A ferrugem é a principal doença da cultura do cafeeiro podendo causar significativas reduções na produtividade da lavoura. A ocorrência desta doença é influenciada por fatores climáticos, tais como chuvas contínuas e temperaturas médias. Fatores ligados à lavoura, como carga pendente e espaçamento também interferem na infecção do patógeno. Neste trabalho foi realizado o acompanhamento do índice de infecção de ferrugem em lavouras localizadas na Fazenda Experimental de Varginha, entre nos agrícolas de 1998/99 a 2006/2007. Para tanto, foram coletadas folhas de talhões sem controle de ferrugem, em lavouras com espaçamento adensado e largo, sendo que para os dois espaçamentos foram utilizadas lavouras com carga pendente alta e baixa. Observou-se que, independentemente do espaçamento, a infecção de ferrugem foi maior nas lavouras com carga pendente alta, na média de todos os anos avaliados. No atual ano agrícola 2006/07 o índice de infecção mostrou-se muito precoce e elevado em relação à média histórica apresentando valores médios de 60 a 70,0% já no mês de fevereiro