Evaporative scribing with a moving CW laser - Effects of multiple reflections and beam polarization

1991 ◽  
Author(s):  
Se Yoon Bang ◽  
Michael F. Modest
Keyword(s):  
Beam Polarization ◽  
Multiple Reflections ◽  
Cw Laser

CW laser machining of hard ceramics—II. Effects of multiple reflections

1993 ◽  
Vol 36 (14) ◽  
pp. 3529-3540 ◽  
Author(s):  
Se Yoon Bang ◽  
Subhransu Roy ◽  
Michael F. Modest
Keyword(s):  
Laser Machining ◽  
Multiple Reflections ◽  
Cw Laser

The Impact of Light Polarisation on Light Field of Scenes with Multiple Reflections

2020 ◽  
pp. 108-115 ◽  
Author(s):  
Vladimir P. Budak ◽  
Anton V. Grimaylo
Keyword(s):  
Mathematical Model ◽  
Light Field ◽  
Global Illumination ◽  
Multiple Reflections ◽  
Software Environment ◽  
The Monte Carlo Method ◽  
Mueller Matrices ◽  
Volume Integration ◽  
The Impact

The article describes the role of polarisation in calculation of multiple reflections. A mathematical model of multiple reflections based on the Stokes vector for beam description and Mueller matrices for description of surface properties is presented. On the basis of this model, the global illumination equation is generalised for the polarisation case and is resolved into volume integration. This allows us to obtain an expression for the Monte Carlo method local estimates and to use them for evaluation of light distribution in the scene with consideration of polarisation. The obtained mathematical model was implemented in the software environment using the example of a scene with its surfaces having both diffuse and regular components of reflection. The results presented in the article show that the calculation difference may reach 30 % when polarisation is taken into consideration as compared to standard modelling.

Structural and Electrical Characterization of Shaped Beam Laser Recrystallized Polysilicon on Amorphous Substrates

1981 ◽  
Vol 4 ◽  
Author(s):  
T. J. Stultz ◽  
J. F. Gibbons
Keyword(s):  
Grain Size ◽  
Electrical Characterization ◽  
Grain Structure ◽  
Electrical Characteristics ◽  
Shaped Beam ◽  
Beam Laser ◽  
Cw Laser ◽  
Amorphous Substrates ◽  
Circular Beam

ABSTRACTStructural and electrical characterization of laser recrystallized LPCVD silicon films on amorphous substrates using a shaped cw laser beam have been performed. In comparing the results to data obtained using a circular beam, it was found that a significant increase in grain size can be achieved and that the surface morphology of the shaped beam recrystallized material was much smoother. It was also found that whereas circular beam recrystallized material has a random grain structure, shaped beam material is highly oriented with a <100> texture. Finally the electrical characteristics of the recrystallized film were very good when measured in directions parallel to the grain boundaries.

Microwave Non-Destructive Testing of Coatings and Paints Using Free Space Microwave Measurement

2005 ◽  
Vol 2 (2) ◽  
pp. 17
Author(s):  
Norhayati Hamzah ◽  
Deepak Kumar Ghodgaonkar ◽  
Kamal Faizin Che Kasim ◽  
Zaiki Awang
Keyword(s):  
Free Space ◽  
Protective Coatings ◽  
Microwave Measurement ◽  
Multiple Reflections ◽  
Destructive Testing ◽  
Lens Antennas ◽  
Coatings And Paints ◽  
Microwave Nondestructive Testing ◽  
Mode Transitions ◽  
Diffraction Effects

Microwave nondestructive testing (MNDT) techniques are applied to evaluate quality of anti-corrosive protective coatings and paints on metal surfaces. A tree-space microwave measurement (FSMM) system is used for MNDT of protective coatings. The FSMM system consists of transmit and receive spot-focusing horn lens antennas, a vector network analyzer, mode transitions and a computer. Diffraction effects at the edges of the sample are minimized by using spot-focusing horn lens antennas. Errors due to multiple reflections between antennas are corrected by using free-space LRL (line, reflect, line) calibration technique. We have measured complex reflection coefficient of polyurethane based paint which is coated on brass plates.

Laser Timing Probe with Frequency Mapping for Locating Signal Maxima

2009 ◽  
Author(s):  
L.S. Koh ◽  
H. Marks ◽  
L.K. Ross ◽  
C.M. Chua ◽  
J.C.H. Phang
Keyword(s):  
Response Time ◽  
Continuous Wave ◽  
Single Point ◽  
Point Measurement ◽  
Cw Laser ◽  
Measurement Capabilities

Abstract A Laser Timing Probe (LTP) system which uses a noninvasive 1.3 µm continuous wave (CW) laser with frequency mapping and single point measurement capabilities is described. The frequency mapping modes facilitate the localization of signal maxima for subsequent single point measurements. Measurements of waveforms with long delays and 50 ps response time from NMOS and PMOS transistors are also shown.

Reflection on Learner-Led Study Abroad Events in a SAC from Three Perspectives: A Learner, an Administrative Staff Member, and an Advisor

Relay Journal ◽  
2020 ◽  
pp. 66-79
Author(s):  
Mizuki Shibata ◽  
Chihiro Hayashi ◽  
Yuri Imamura
Keyword(s):  
Study Abroad ◽  
Language Learning ◽  
Support System ◽  
Staff Member ◽  
Administrative Staff ◽  
Multiple Reflections ◽  
Learning Space ◽  
Japanese University ◽  
Staff Members

This paper reports on a case study of learner-led study-abroad events in the language learning space at a Japanese University. We present multiple reflections on the events from different perspectives: the event organizer (student), an administrative staff member, and a learning advisor working at the center. We also introduce the support system that a group of administrative staff members and learning advisors are in charge of helping learners to hold their events. Moreover, throughout our reflections, several factors that made the learner-led study-abroad events sustainable and successful are demonstrated.

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