Femtosecond pulsed laser damage of Silicon (100) with thermal oxide thin films was studied in order to further understand the optical and electrical properties of thin films and to evaluate their influence on the dama...
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Anomalous growth of silicon (Si) nanocrystals (NCs) was observed during Raman scattering measurements of nanosilica SiOx (x=0.9) powder with an average diameter of 40 nm. It was found that Si NCs were formed by exposu...
Anomalous growth of silicon (Si) nanocrystals (NCs) was observed during Raman scattering measurements of nanosilica SiOx (x=0.9) powder with an average diameter of 40 nm. It was found that Si NCs were formed by exposure to the laser beam. This photo-assisted synthesis is similar to the thermal synthesis of Si NCs, which forms Si NCs by thermally decomposing SiOx into Si and SiO2. However, the photo-assisted synthesis is more effective in forming Si NCs than the thermal synthesis. Even one second after irradiation of the nanosilica SiOx powder with laser, Si NCs with an average size of 5 nm were formed. The Si NC size increases with increasing the laser power and exposure time. It is interesting to observe a self-limited size for higher laser power and prolonged exposure. The photo-assisted synthesis of Si NCs is proved to be a promising technique with a wide range of applications in nanotechnology.
Nanomorphing with ultrafast lasers may have a significant role in direct write stamp production. Surface conditions play a critical role in the ablative properties of materials. We have conducted femtosecond laser (pu...
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Ni/Al nanostructured multilayer foils were machined with femtosecond pulse-length laser irradiation at various fluences. Scanning electron microscopy, back-scattered electron detection, and atomic force microscopy wer...
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Ni/Al nanostructured multilayer foils were machined with femtosecond pulse-length laser irradiation at various fluences. Scanning electron microscopy, back-scattered electron detection, and atomic force microscopy were used to characterize the resulting laser modified regions. We show that material removal at the micron scale is possible with no ignition of a self-propagation reaction emanating from the irradiated areas, a danger minimized by the fact that the extremely short time duration of the pulse produces negligible heat dissipation into the multilayer system. Nevertheless, initial AFM and BSE results give indication that multilayers may be intermixing and reacting locally in areas smaller than the laser beam diameter, though the exact ignition mechanism is still to be determined.
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STERN, HMETZGER, RHoward K. Stern:is presently vice president of Robotic Vision Systems
Inc. He received a bachelor of electrical engineering degree from College of the City of New York in 1960. Mr. Stern joined Dynell Electronics Corporation in 1971 and became part of the Robotic Vision Systems
Inc. staff at the time of its spin-off from Dynell. He was program manager of the various three-dimensional sensing and replication systems constructed by Dynell and Robotic Vision Systems. As program manager his responsibilities encompassed technical administrative and operational areas. The first two portrait sculpture studio systems and the first three replication systems built by Robotic Vision Systems Inc. were designed manufactured and operated under his direction. Before joining Dynell
Mr. Stern was a senior engineer at Instrument Systems Corporation and chief engineer of the Special Products Division of General Instrument Corporation. Prior to these positions Mr. Stern was chief engineer of Edo Commercial Corporation. At General Instrument and Edo Commercial he was responsible for the design and manufacture of military and commercial avionics equipment. Mr. Stern is presently responsible for directing the systems design and development for all of the company's programs.Robert J. Metzger:is currently engineering group leader at Robotic Vision Systems
Inc. He graduated summa cum laude from the Cooper Union in 1972 with a bachelor of electrical engineering degree. Under sponsorship of a National Science Foundation graduate fellowship he graduated from the Massachusetts Institute of Technology in 1974 with the degrees of electrical engineer and master of science (electrical engineering). In 1979 Mr. Metzger graduated from Polytechnic Institute of New York with the degree of master of science (computer science). Since 1974
Mr. Metzger has been actively engaged in the design of systems and software for noncontact threedimensional optical measurement for both military and commercial applications. Of particular note are his c
Ship's propellers are currently measured by manual procedures using pitchometers, templates and gauges. This measurement process is extremely tedious, labor intensive and time consuming. In an effort to provide in...
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Ship's propellers are currently measured by manual procedures using pitchometers, templates and gauges. This measurement process is extremely tedious, labor intensive and time consuming. In an effort to provide increased accuracy, repeatability and cost effectiveness in propeller manufacture, an automated propeller optical measurement system (APOMS) has been built which rapidly and automatically scans an entire ship's propeller using a 3-D vision sensor. This equipment is integrated with a propeller robotic automated templating system (PRATS) and the propeller optical finishing system (PROFS) which robotically template and grind the propeller to its final shape, using the APOMS-derived data for control feedback. The optical scanning and the final shape are both controlled by CAD/CAM data files describing the desired propeller shape. An automated propeller balancing system is incorporated into the PROFS equipment. The APOMS/PRATS/PROFS equipment is expected to provide lower propeller manufacturing costs.
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