Investigation of superfast deposition of metal oxide and Diamond-Like Carbon thin films by nanosecond Ytterbium (Yb+) fiber laser

Metal oxide (MOx, M: titanium, magnesium) and Diamond-Like Carbon (DLC) thin films were synthesized by Pulsed Laser Deposition (PLD) at room temperature and low vacuum of 2 Pa for MOx and vacuum of 4 x 10(-3) Pa for DLC films. A fiber based Ytterbium (Yb+) laser operating in the nanosecond regime at a repetition rate of 20 kHz was used as an ablation source. Dense and smooth thin films with a thickness from 120 to 360 nm and an area of up to 10 cm(2) were deposited on glass and stainless steel substrates at high growth rates up to 2 nm/s for a laser intensity of 10-12 J/cm(2). The thin films synthesis was compared for two fiber laser modes of operation, at a repetition rate of 20 kHz and with an additional modulation at 1 kHz. The morphology, chemical composition and structure of the obtained thin films were evaluated using optical microscopy, Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDX) and Raman spectroscopy. The morphology of the MOx thin films and the deposition rate strongly depend on the fiber laser mode of operation. Very smooth surfaces were obtained for the metal oxide thin films deposited at lower deposition rates in the modulation mode at 1 kHz. The effect of the substrate on the DLC film structure was studied. The films deposited on dielectric substrates were identified as typical tetrahedral (ta-C) DLC with high sp(3) content. DLC films on metal substrates were found typical a-C amorphous carbon films with mixing sp(2)/sp(3) bonds

Global governance approaches to addressing illegal logging: Uptake and lessons learned

One of the most challenging tasks facing development agencies, trade ministries, environmental groups, social activists and forest-focused business interests seeking to ameliorate illegal logging and related timber trade is to identify and nurture promising global governance interventions capable of helping improve compliance to governmental policies and laws at national, subnational and local levels. This question is especially acute for developing countries constrained by capacity challenges and “weak states” (Risse, 2011). This chapter seeks to shed light on this task by asking four related questions: How do we understand the emergence of illegal logging as a matter of global interest? What are the types of global interventions designed to improve domestic legal compliance? How have individual states responded to these global efforts? What are the prospects for future impacts and evolution? We proceed in the following steps. Following this introduction, step two reviews how the problem of “illegal logging” emerged on the international agenda. Step three reviews leading policy interventions that resulted from this policy framing. Step four reviews developments in selected countries/regions around the world according to their place on the global forest products supply chain: consumers (United States, Europe and Australia); middle of supply chain manufacturers (China and South Korea) and producers (Russia; Indonesia; Brazil and Peru; Ghana, Cameroon and the Republic of Congo). We conclude by reflecting on key trends that emerge from this review relevant for understanding the conditions through which legality might make a difference in addressing critical challenges

NLO properties of new stryquinolinium dye thin films deposited by pulsed laser deposition

International audienc

Large nonlinear optical properties of new styrylquinolinium dye thin films deposited by pulsed laser deposition

Date du colloque&nbsp;: 09/2011</p

Novel Styrylquinolinium Dye Thin Films Deposited by Pulsed Laser Deposition for Nonlinear Optical Applications

The nonlinear optical (NLO) properties of novel styrylquinolinium dye thin films for photonic applications have been studied by the Z-scan, second harmonic generation (SHG), and third harmonic generation (THG) techniques, providing both the second- and third-order nonlinear optical parameters. The styrylquinolinium dye (E)-1-ethyl-4-(2-(4-hydroxynaphthalen-1-yl)vinyl)quinolinium bromide was synthesized by the Knoevenagel condensation, and its structure and physicochemical properties were determined by H-1 NMR, C-13 NMR, FTIR, UV-vis spectroscopy, and elemental analysis. Functional thin films were deposited by pulsed laser deposition (PLD) using UV TEA N-2 laser onto glass substrates and KCl, NaCl monocrystals at room temperature and vacuum at 10(-3) mbar/0.1 Pa. Further characterization of the films and target from native material by FTIR spectroscopy revealed that there was no difference between the deposited films and the initial material. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) measurements have been also performed in order to provide information about the morphology and topology of the thin films

Use of technology virtual reality for the study of human - Operator in extreme conditions

Astronaut's training includes self-forming a mental model of the upcoming flight. In fact, this model consists of images of the

Empirical Models to Characterize the Structural and Physiochemical Properties of Vacuum Gas Oils with Different Saturate Contents

Inter-criteria analysis was employed in VGO samples having a saturate content between 0.8 and 93.1 wt.% to define the statistically significant relations between physicochemical properties, empirical structural models and vacuum gas oil compositional information. The use of a logistic function and employment of a non-linear least squares method along with the aromatic ring index allowed for our newly developed correlation to accurately predict the saturate content of VGOs. The empirical models developed in this study can be used not only for obtaining the valuable structural information necessary to predict the behavior of VGOs in the conversion processes but can also be utilized to detect incorrectly performed SARA analyses. This work confirms the possibility of predicting the contents of VGO compounds from physicochemical properties and empirical models