Determining the chronological sequence of inks deposited with different writing and printing tools using ion beam analysis

Determining the sequence of inks in a questioned document is important in forensic science. Conventional and micro beam-based ion beam analysis using Rutherford backscattering spectrometry (RBS) and particle-induced X-ray emission were employed to study the depth distribution of chemical elements in plain paper and inks/toner deposited by different pens as well as inkjet and laser printers. Composition depth profiling with high lateral resolution was performed with focus on areas where two different coloring agents overlapped. We identify under which conditions the sequence of inks deposited can be reconstructed, analyzing the continuity of characteristic contributions to the obtained signals, with a focus on the depth-resolved RBS data. The order of deposition was correctly determined for combinations of two different laser printers and in certain cases for pens. Results indicate a potential for analysis, depending on the composition of staining agent, that is, in particular if heavy species are present in sufficiently high concentration. In such cases, also characters obscured or modified by an agent of different composition can be revealed. Changing the probing depth by modifying the beam energy could yield additional information

Structural and optical properties of InAs nanoclusters synthesised by low energy ion implantation in Si followed by RTA

International audienc

On the Z(1)-dependence of electronic stopping in TiN

We present a thorough experimental study of electronic stopping of H, He, B, N, Ne and Al ions in TiN with the aim to learn about the energy loss mechanisms of slow ions. The energy loss was measured by means of time-of-flight medium-energy ion scattering. Thin films of TiN on silicon with a delta-layer of W at the TiN/Si interface were used as targets. We compare our results to non-linear density functional theory calculations, examining electron-hole pair excitations by screened ions in a free electron gas in the static limit, with a density equivalent to the expected value for TiN. These calculations predict oscillations in the electronic stopping power for increasing atomic number Z(1) of the projectile. An increasing discrepancy between our experimental results and predictions by theory for increasing Z(1) was observed. This observation can be attributed to contributions from energy loss channels different from electron-hole pair excitation in binary Coulomb collisions

High-power impulse magnetron sputter deposition of TiBx thin films : Effects of pulse length and peak current density

We report on a systematic study of the effect of pulse length (ton=25−200μs), and peak target current density (JT,peak=0.25−2.0A/cm2) during HiPIMS deposition of AlB2-phase TiBx thin films from a TiB2 target at a pressure of pAr=1.33Pa(10mTorr) and substrate temperature Ts=500°C. All films are under-stoichiometric with B/Ti = 1.36–1.89, with the higher values corresponding to longer pulses and higher JT,peak values. While the deposition flux, including both ions and neutrals, in general increases with increasing ton and JT,peak, the Ti+ ion flux saturates, resulting in the higher B/Ti values under these conditions. Thus, the relative amount of Ti ionization, and the degree to which these ions are guided toward the substrate by magnetic fields, are main modulators determining the composition of TiBx thin films

Biased quartz crystal microbalance method for studies of chemical vapor deposition surface chemistry induced by plasma electrons

A recently presented chemical vapor deposition (CVD) method involves using plasma electrons as reducing agents for deposition of metals. The plasma electrons are attracted to the substrate surface by a positive substrate bias. Here, we present how a standard quartz crystal microbalance (QCM) system can be modified to allow applying a DC bias to the QCM sensor to attract plasma electrons to it and thereby also enable in situ growth monitoring during the electron-assisted CVD method. We show initial results from mass gain evolution over time during deposition of iron films using the biased QCM and how the biased QCM can be used for process development and provide insight into the surface chemistry by time-resolving the CVD method. Post-deposition analyses of the QCM crystals by cross-section electron microscopy and high-resolution x-ray photoelectron spectroscopy show that the QCM crystals are coated by an iron-containing film and thus function as substrates in the CVD process. A comparison of the areal mass density given by the QCM crystal and the areal mass density from elastic recoil detection analysis and Rutherford backscattering spectrometry was done to verify the function of the QCM setup. Time-resolved CVD experiments show that this biased QCM method holds great promise as one of the tools for understanding the surface chemistry of the newly developed CVD method.Funding Agencies|Swedish Research Council (VR) [2015-03803, 2019-05055]; Swedish Foundation for Strategic Research [15-0018]; Lam Research Corporation</p

Leitura: um guia sobre teoria(s) e prática(s)

Livro didático para uso em atividades de aula presencial e em modalidades EAD de cursos de Letras/Tradução. Temática voltada para a formação em Leitura para tradutores e revisores.PDF: Estes arquivos não podem ser editados, pois é um formato fechado.Este formato permite que sejam feitas edições - como marcação de texto e comentários, além de preenchimento de formulários - caso o autor permita. Estes arquivos podem ser visualizados no Adobe Acrobat reader ou no navegador da web. Versão do PDF: 1.5 (Acrobat 6.x). Epub: Estes arquivos podem ser editados em qualquer editor de texto, como o Notepad++, desde que o conteúdo do epub seja extraído.EbookNosso E-BOOK pode ser usado em atividades EAD e também em atividades presenciais em cursos de Letras que tratem do tema da Leitura. A parte sobre complexidade textual é bastante produtiva para execícios com vários tipos de textos de temática científica