Search results for "placement"

Surface acceleration during dry laser cleaning of silicon

1999

We report on measurements of the surface acceleration for the application of dry laser cleaning. For that purpose, industrial silicon samples were irradiated by a frequency-doubled Q-switched Nd:YAG laser. The surface displacement was measured by a heterodyne interferometer and recorded by a digital storage oscilloscope. Several hundreds of shots were averaged to give smooth displacement curves which could be derived numerically. The experiments show that the highest accelerations, which are thought to be responsible for the cleaning, occur on the time scale of the laser pulse. Simple theoretical models are in good agreement with the experimental data. The maximal displacement depends only …

Some aspects of formation and tribological properties of silver nanodumbbells.

2013

In this paper, metal nanodumbbells (NDs) formed by laser-induced melting of Ag nanowires (NWs) on an oxidized silicon substrate and their tribological properties are investigated. The mechanism of ND formation is proposed and illustrated with finite element method simulations. Tribological measurements consist in controllable real-time manipulation of NDs inside a scanning electron microscope (SEM) with simultaneous force registration. The geometry of NDs enables to distinguish between different types of motion, i.e. rolling, sliding and rotation. Real contact areas are calculated from the traces left after the displacement of NDs and compared to the contact areas predicted by the contact m…

2017

Joint replacement surgery is associated with significant morbidity and mortality following infection with either methicillin-resistant Staphylococcus aureus (MRSA) or Staphylococcus epidermidis. These organisms have strong biofilm-forming capability in deep wounds and on prosthetic surfaces, with 103 -104 microbes resulting in clinically significant infections. To inhibit biofilm formation, we developed 3D titanium structures using selective laser melting and then coated them with a silver nanolayer using atomic layer deposition. On bare titanium scaffolds, S. epidermidis growth was slow but on silver-coated implants there were significant further reductions in both bacterial recovery (p < …

Light-induced ionic processes in optical oxide glasses

1991

Abstract The density of optical glasses is changed by the influence of light capable of generating color centers in these materials. Such defect generation is not only an electronic process, but an atomic displacement is also necessary. The strong localization of electronic and vibrational excitations in the glass network leads to the high efficiency of sub-threshold defect generation. Secondary ionic processes lead to the changes of basic glass properties (light refractive index, density, mechanical strength, etc.); thus, it is possible to use optical glasses as light detectors for appropriate wavelengths.

Experimental Study Regarding of Bending Behaviour of Stabilizator Link

2016

Abstract This paper presents an experimental study of the behavior of anti-roll power link subjected to bending, power link coming from an Opel Astra G. The power link is made of PA66 GF30 polyamide. For this study, there were used a universal testing machine (Instron 5587) and a real-time strain measurement optical system (Aramis). The results showed are those obtained in the case of a compression force of 1,000 [N] namely: major Strain ε1, minor strain ε2, equivalent von Mises strain, displacement on X axis, displacement on Y axis (compression force direction), displacement on Z axis.

Solid-fluid interaction in a pillar-based phononic crystal

2016

In this paper, we investigate the wave dispersion of two dimensional pillar-based phononic crystal surrounded in liquid medium. An unit cell structure with reduced pillar height (hp/a)=0.5 and reduced radius (rp/a)=0.3 is simulated using Finite Element Method. The geometrical parameter is chosen to demonstrate a local resonance mechanism that allow the confinement of elastic energy at the interface between the solid and the fluid. In order to identify the energy distribution, we represent the eigenmode at high symmetry (point X) in the first Brillouin zone. The decreasing trend of frequency is also boosted with the increase of pillar height. From the total displacement, the energy is mostly…

Analysis of Rectangular Orthotropic Membranes for Mechanical Properties Identification through Load-Displacement Data

2021

In this paper, an innovative procedure is introduced for the identification of the mechanical properties of orthotropic membranes based on load-displacement data. To this end, novel functional forms of the displacement components for rectangular membranes are appropriately introduced. Unknown coefficients of these displacement functions are determined, minimizing the total potential energy of the membrane. The energy method is then combined with an optimization procedure to estimate the elastic constants of the membranes in a straightforward manner. Specifically, a genetic algorithm is used to minimize a properly defined objective function directly related to the sought mechanical propertie…

Approximate Solution on Large Deflection of Glass Panels Subjected to Uniform Pressure

2015

The estimation of the deflection of glass panels under wind pressure is important in designing external facades of buildings. A direct method to compute the large deflections of glass panels under uniform loads such as wind pressure is presented. The model allows for derivation of the load-deflection response of square or rectangular multilayered glass panels subject to uniform loads. The boundary conditions examined are those of four-point discontinuous supports or continuous supports along the four sides. With some assumptions on bending and membrane action of flat glasses, simple analytical expressions were derived from the elastic theory. Viscoelastic effects for multilayered glass pane…

Focusing of surface-acoustic-wave fields on (100) GaAs surfaces

2003

Focused surface-acoustic waves (SAWs) provide a way to reach intense acoustic fields for electro- and optoacoustic applications on semiconductors. We have investigated the focusing of SAWs by interdigital transducers (IDTs) deposited on (100)-oriented GaAs substrates. The focusing IDTs have curved fingers designed to account for the acoustic anisotropy of the substrate. Different factors that affect focusing, such as the aperture angle and the configuration of the IDT fingers, were systematically addressed. We show that the focusing performance can be considerably improved by appropriate choice of the IDT metal pads, which, under appropriate conditions, create an acoustic waveguide within t…

Experiences with applications of macromolecular tools in supramolecular crystallography

2014

Supramolecular structures, with ever increasing size ranging from a few up to tens of nanometres, represent an intermediate stage between small molecules and biological macromolecules. Many crystal structures of these large supramolecular assemblies have been solved using dual space algorithms. However, supramolecular assemblies with a capsular shape present a particular challenge for crystallography, especially when they are chiral and composed of only light atoms. In this paper, we show that the application of “routine” macromolecular tools may be of great help in solving the crystal structures of supramolecular assemblies that are otherwise refractory to the routine methods of small mole…