Search

Submitted by phemiran@stj.jus.br (phemiran@stj.jus.br) on 2022-06-13T17:48:52Z No. of bitstreams: 2 negocios_juridicos_processuais_gasparetti.pdf: 3758380 bytes, checksum: 131e1b912c2ea7d4f81ab69cdffd36f1 (MD5) license.txt: 1239 bytes, checksum: c9b4c351324448672315a00808efb725 (MD5) Approved for entry into archive by betanial@stj.jus.br (betanial@stj.jus.br) on 2022-06-19T14:35:26Z (GMT) No. of bitstreams: 2 negocios_juridicos_processuais_gasparetti.pdf: 3758380 bytes, checksum: 131e1b912c2ea7d4f81ab69cdffd36f1 (MD5) license.txt: 1239 bytes, checksum: c9b4c351324448672315a00808efb725 (MD5) Made available in DSpace on 2022-06-19T14:35:26Z (GMT). No. of bitstreams: 2 negocios_juridicos_processuais_gasparetti.pdf: 3758380 bytes, checksum: 131e1b912c2ea7d4f81ab69cdffd36f1 (MD5) license.txt: 1239 bytes, checksum: c9b4c351324448672315a00808efb725 (MD5) Previous issue date: 2022

We perform in-situ transmission electron microscopy (TEM) experiments of silver nanoparticles channeling on mono-, bi-, and few-layer graphene and discover that the interactions in the one-dimensional particle–graphene contact line are sufficiently strong so as to dictate the three-dimensional shape of the nanoparticles. We find a characteristic faceted shape in particles channeling along graphene ⟨100⟩ directions that is lost during turning and thus represents a dynamic equilibrium state of the graphene–particle system. We propose a model for the mechanism of zigzag edge formation and an explanation of the rate-limiting step for this process, supported by density functional theory (DFT) calculations, and obtain a good agreement between the DFT-predicted and experimentally obtained activation energies of 0.39 and 0.56 eV, respectively. Understanding the origin of the channels' orientation and the strong influence of the graphene lattice on the dynamic behavior of the particle morphology could be crucial f...

Porphyrin-like metal-functionalized graphene structures have been investigated as possible catalysts for CO2 and CO reduction to methane or methanol. The late transition metals (Cu, Ag, Au, Ni, Pd, Pt, Co, Rh, Ir, Fe, Ru, Os) and some p (B, Al, Ga) and s (Mg) metals comprised the center of the porphyrin ring. A clear difference in catalytic properties compared to extended metal surfaces was observed owing to a different electronic nature of the active site. The preference to bind hydrogen, however, becomes a major obstacle in the reaction path. A possible solution to this problem is to reduce CO instead of CO2. Volcano plots were constructed on the basis of scaling relations of reaction intermediates, and from these plots the reaction steps with the highest overpotentials were deduced. The Rh–porphyrin-like functionalized graphene was identified as the most active catalyst for producing methanol from CO, featuring an overpotential of 0.22 V. Additionally, we have also examined the hydrogen evolution and o...

Cruciform motifs with two orthogonally oriented π-extended tetrathiafulvalenes and with differently protected thiolate end-groups are synthesized by stepwise coupling reactions. The molecules are subjected to single-molecule conductivity studies in a break-junction and to conducting probe atomic force microscopy studies in a self-assembled monolayer on gold.

The triazatriangulene (TATA) ring system was investigated as a binding group for tunnel junctions of molecular wires on gold surfaces. Self-assembled monolayers (SAMs) of TATA platforms with three different lengths of phenylene wires were fabricated, and their electrical conductance was recorded by both conducting probe-atomic force microscopy (CP-AFM) and scanning tunneling microscopy (STM). Similar measurements were performed for phenylene SAMs with thiol anchoring groups as references. It was found that, despite the presence of a sp(3) hybridized carbon atom in the conduction path, the TATA platform displays a contact resistance only slightly larger than the thiols. This surprising finding has not been reported before and was analyzed by theoretical computations of the transmission functions of the TATA anchored molecular wires. The relatively low contact resistance of the TATA platform along with its high stability and directionality make this binding group very attractive for molecular electronic measurements and devices.

We present an implementation of localized atomic orbital basis sets in the projector augmented wave (PAW) formalism within the density functional theory (DFT). The implementation in the real-space GPAW code provides a complementary basis set to the accurate but computationally more demanding grid representation. The possibility to switch seamlessly between the two representations implies that simulations employing the local basis can be fine tuned at the end of the calculation by switching to the grid, thereby combining the strength of the two representations for optimal performance. The implementation is tested by calculating atomization energies and equilibrium bulk properties of a variety of molecules and solids, comparing to the grid results. Finally, it is demonstrated how a grid-quality structure optimization can be performed with significantly reduced computational effort by switching between the grid and basis representations., 10 pages, 5 figures. http://prb.aps.org.globalproxy.cvt.dk/abstract/PRB/v80/i19/e195112

We report a systematic theoretical investigation of the effects of metal substrates on the local magnetic moments of zigzag graphene nanoribbons (ZGNRs). Representative metal surfaces of Au, Pt, Ni, Cu, Al, Ag, and Pd have been analyzed from atomic first principles. Results show that the local magnetic moments vanish when the nanoribbons are on top of the surfaces of Al, Ag, Pt, and Pd, while they are preserved for Au, Ni, and Cu. For $s$-dominated metals, the magnetic moments of the edge states of ZGNRs can be tuned by a bias voltage. For $p$- or $d$-dominated metals there is significant hybridization between the metal states and the nonbonding $\ensuremath{\pi}$ orbital of the ZGNRs; thereby the tuning effect is reduced. We identify the microscopic physical reason behind the bias tuning of the magnetic properties of the ZGNRs.

Electronic structure calculations have become an indispensable tool in many areas of materials science and quantum chemistry. Even though the Kohn-Sham formulation of the density-functional theory (DFT) simplifies the many-body problem significantly, one is still confronted with several numerical challenges. In this article we present the projector augmented-wave (PAW) method as implemented in the GPAW program package (https://wiki.fysik.dtu.dk/gpaw) using a uniform real-space grid representation of the electronic wavefunctions. Compared to more traditional plane wave or localized basis set approaches, real-space grids offer several advantages, most notably good computational scalability and systematic convergence properties. However, as a unique feature GPAW also facilitates a localized atomic-orbital basis set in addition to the grid. The efficient atomic basis set is complementary to the more accurate grid, and the possibility to seamlessly switch between the two representations provides great flexibility. While DFT allows one to study ground state properties, time-dependent density-functional theory (TDDFT) provides access to the excited states. We have implemented the two common formulations of TDDFT, namely the linear-response and the time propagation schemes. Electron transport calculations under finite-bias conditions can be performed with GPAW using non-equilibrium Green functions and the localized basis set. In addition to the basic features of the real-space PAW method, we also describe the implementation of selected exchange-correlation functionals, parallelization schemes, Delta SCF-method, x-ray absorption spectra, and maximally localized Wannier orbitals.

Trata-se de jurisprudência comentada. Submitted by Raissa da Veiga de Menêses null (rmeneses@stj.jus.br) on 2011-09-29T17:59:32Z No. of bitstreams: 1 stj_consolida_entendimento_gasparetti.pdf: 67835 bytes, checksum: 6b86ce05b1c13f279ed0ef2a6969a7e8 (MD5) Approved for entry into archive by Thamara Nunes Reis de Alcantara null(thamara@stj.jus.br) on 2012-02-09T10:55:06Z (GMT) No. of bitstreams: 1 stj_consolida_entendimento_gasparetti.pdf: 67835 bytes, checksum: 6b86ce05b1c13f279ed0ef2a6969a7e8 (MD5) Made available in DSpace on 2012-02-09T10:55:07Z (GMT). No. of bitstreams: 1 stj_consolida_entendimento_gasparetti.pdf: 67835 bytes, checksum: 6b86ce05b1c13f279ed0ef2a6969a7e8 (MD5) Previous issue date: 2011-01 Trata-se de comentário a decisão proferida pelo STJ referente à necessidade de participação da ANATEL em demandas coletivas.

The stability of graphene nanoribbons in the presence of typical atmospheric molecules is systematically investigated by means of density-functional theory. We calculate the edge formation free energy of five different edge configurations passivated by H, ${\text{H}}_{2}$, O, ${\text{O}}_{2}$, ${\text{N}}_{2}$, CO, ${\text{CO}}_{2}$, and ${\text{H}}_{2}\text{O}$, respectively. In addition to the well known hydrogen passivated armchair and zigzag edges, we find the edges saturated by oxygen atoms to be particularly stable under atmospheric conditions. Saturation of the zigzag edge by oxygen leads to the formation of metallic states strictly localized on the oxygen atoms. Finally, the vibrational spectrum of the hydrogen- and oxygen-passivated ribbons are calculated and compared.

We use density functional theory (DFT) with a recently developed van der Waals density functional (vdW-DF) to study the adsorption of graphene on Al, Cu, Ag, Au, Pt, Pd, Co and Ni(111) surfaces. In constrast to the local density approximation (LDA) which predicts relatively strong binding for Ni,Co and Pd, the vdW-DF predicts weak binding for all metals and metal-graphene distances in the range 3.40-3.72 \AA. At these distances the graphene bandstructure as calculated with DFT and the many-body G$_0$W$_0$ method is basically unaffected by the substrate, in particular there is no opening of a band gap at the $K$-point., Comment: 4 pages, 3 figures