In this paper we report on the fabrication of regular arrays silica nanoneedles by deposition a thin layer patterned polymer nanowires (or nanohair). An array high-aspect-ratio nanoscale diameter holes depths greater than 10 µm was produced at surface fused wafer an amplified femtosecond laser system operated in single-pulse mode. Cellulose acetate (CA) film imprinted into nanoholes and peeled off to form standing CA nanowires, negative replica machined nanoholes. The cellulose then coated...

Microfluidic devices designed for chemotaxis assays were fabricated on fused silica substrates using femtosecond laser micromachining. These have built-in chemical concentration gradient forming structures and are ideally suited establishing passive diffusion gradients over extended periods of time. Multiple structures, with identical or distinct characteristics, can be integrated into a single device, migrating cells directly observed an inverted microscope. In this paper, the design,...

The uniquely low friction behavior of near-frictionless carbon (NFC) as compared to conventional diamondlike (DLC) is determined by the bonding within film. Inelastic neutron scattering (INS) and Fourier transform infrared (FTIR) spectroscopy were used probe environment hydrogen; both INS FTIR can whole sample. Previous work has focused on surface studies; present results show that in film a majority hydrogen adjacent sp3-bonded carbon. In addition this absence any molecular NFC.

The authors characterize femtosecond laser single-pulse machining of deep, micrometer-diameter holes and long, micrometer-width channels in fused silica by the use spherical, cylindrical, aspheric singlet lenses. Repositionable spherical lenses form an adjustable beam expander that also provides a means minimizing—or deliberately introducing—spherical aberration (SA) focal region controlling divergence at asphere. Inserting cylindrical creates line focus for channel patterns parallel to...

Tungsten-titanium-carbon base alloys are a promising candidate material for high performance propulsion systems, given their ability to form carbide-metal composites having fine microstructure consisting of dispersion hard titanium carbide particles within tough tungsten rich metal matrix. These temperature, non-eroding materials can be produced by laser melting mixtures and powders. The fabrication cast composite components via based solid freeform techniques is currently being explored at...

Purpose The purpose of this paper is to develop a simple, easy implement powder delivery strategy for solid freeform fabrication (SFF) processing. Design/methodology/approach A specially designed “tower nozzle” located at the center processing area dispenses feedstock powders continuously and uniformly onto area, where accumulate progressively as flat bed. During dispensing, are selectively consolidated by melting solidification using laser beam which was scanned in predefined pattern...

We report on the feasibility of preparing nickel and niobium nitride coated cellulose acetate (CA) topographical features through a combination template-synthesis sputter deposition. Using femtosecond laser micromachining, template was produced by patterning fused silica substrate with square array holes estimated depth <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$&gt; 10\ \mu \mathbf{m}$</tex> . The subjected to CA polymer thin-film...

Exceptionally deep submicron-diameter holes and long microchannels are machined in fused silica by single femtosecond pulses using spherical, cylindrical, aspheric lenses. These features result from a combination of longitudinal spherical aberration filamentation.

Graphite is a high temperature structural material due to its low specific gravity and strength along with exceptional chemical physicomechanical properties. However, graphite other carbon materials suffer oxidation are easily eroded by particle gas streams. One of the ways improve these properties making adherent protective coatings on materials. The adherence depends their wettability difference in values coefficient thermal expansion that material. transition metals have outstanding...

Femtosecond laser machining of fused silica (SiO2) was used to fabricate biomolecule concentration gradient forming microfluidic devices specifically designed for cellular imaging purposes during chemotaxis. These novel cell can replace standard Gundersen and Barrett based micropipette systems, are re-usable, have superior optical properties, may include both micro nanofluidic channels. The dimensional surface characteristics these channels be precisely tailored as a function the...

Abstract This paper reports the deposition of transition metal coatings on graphite by laser melting a pre-placed layer powder particles using continuous wave (CW) laser. Titanium, zirconium, and niobium were successfully deposited semiconductor grade plates induced surface improvement (LISI) approach. The produced characterized scanning electron microscope, energy dispersive spectrometry, X-ray diffraction, microhardness testing, secondary ion mass spectrometry. Results show formation...