Two-Dimensional Measurements of Lubricant Spreading on Diamond-Like-Carbon Surface Using Image Processing on Fringe Patterns Formed by Michelson Interferometry

2000 ◽  
Vol 123 (1) ◽  
pp. 188-195 ◽  
Author(s):  
Yasunaga Mitsuya ◽  
Hedong Zhang ◽  
Sakiko Ishida
Keyword(s):  
Image Processing ◽  
Front Surface ◽  
Stratified Medium ◽  
Back Surface ◽  
Diamond Like Carbon ◽  
Back Side ◽  
Fringe Shift ◽  
Scanning Method ◽  
Glass Disk ◽  
Fringe Patterns

A Michelson interferometer based on the Linnik microscope configuration has been constituted and applied to the measurement of lubricant spreading on diamond-like-carbon (DLC) surface. Performing image processing on the fringe patterns formed by the interferometer, the lubricant thickness, as well as the spreading behavior can be investigated. This method provides complete line profiles in two dimensions and permits direct observation of the spreading phenomena, in contrast to the conventional point-by-point scanning method. To improve the measurement accuracy, a fringe following technique and a noise suppression technique were introduced. The fringe following technique successfully prevented a fringe shift over the visual field and thus suppressed the pseudo phase shift caused by a fringe shift. The spatially fixed noise due to non-uniform laser beams and flaws in optical components was also efficiently suppressed by the noise compensation method. From the calculation of multiple beam interference in a stratified medium, it is found that reduction in sensitivity due to additional reflections from underlayers is effectively prevented if the lubricant is observed through a glass disk using reflections on the back surfaces of the glass and lubricant, instead of being observed on a disk using the front surface reflections. Utilizing this advantage, a novel scheme was employed to give maximum sensitivity in which lubricant was coated on the back side of a glass disk whose front surface was coated with non-reflecting film and whose back surface was sputtered with the proper thickness of DLC. The enhanced resolution attained by the new scheme was experimentally confirmed by observing lubricant on the back surface of the glass disk and the front surface of a magnetic disk.

Analysis of transition metal induced surface defects in silicon following apid thermal processing

1989 ◽  
Vol 47 ◽  
pp. 458-459
Author(s):  
R. Kola
Keyword(s):  
Thermal Processing ◽  
Defect Structure ◽  
Surface Defects ◽  
Defect Formation ◽  
Front Surface ◽  
Back Surface ◽  
Back Side ◽  
Plan View ◽  
Vlsi Technology ◽  
Sputter Deposited

Rapid Thermal Processing(RTP) is extensively used in VLSI technology for implant activation, licidation, oxidation, and passivation glass reflow. The diffusion of back-side depositions of transition metals during rapid thermal annealing and the resulting front-side defect formation in silicon has recently been investigated by several authors but a detailed analysis of the defect structure, morphology, and chemistry is lacking. The defect structure and chemistry on both the front and back sides of the wafers ter RTA were investigated by TEM on plan-view and cross-section foils. A Philips EM430 microscope ierating at 300 KeV and a Hitachi H-800 microscope operating at 200 KeV were used. Ni and Cu sputter deposited on the back-side of 4 inch diameter (100) Si wafers were diffused for 10 sec at 1150°C in trogen ambient. The thickness of the metal film was 50 nm. A Heatpulse 2101 RTA system was used.Fig. 1 is a CDF micrograph showing a group of precipitates on the front surface of a sample nickel diffused from the back surface.

Three-Dimensional Measurement of Head Flying Height and Attitude Using Image Processing of Fringe Patterns Formed by Michelson Laser Interferometry

1996 ◽  
Vol 118 (3) ◽  
pp. 564-570 ◽  
Author(s):  
Yasunaga Mitsuya ◽  
Akihito Mitsui ◽  
Yasuyuki Kawabe ◽  
Lars Lunde
Keyword(s):  
Image Processing ◽  
High Speed ◽  
Contact Region ◽  
Three Dimensional ◽  
Ccd Camera ◽  
Laser Interferometry ◽  
Disk Surface ◽  
Flying Height ◽  
Back Surface ◽  
Fringe Patterns

In-situ measurement of head flying height and attitude using image processing of fringe patterns formed by Michelson interferometry is studied. A wide laser beam is applied to illuminate the slider back surface and disk surface simultaneously to create interferometric fringe patterns. Employing the relationships arising between the two fringe patterns, the calculation procedure is formulated to yield the slider’s parallel, pitch and roll displacements. Experimental fringe patterns are captured in a single visual field by a high-speed CCD camera. Image processing for a higher signal-to-noise ratio, such as smoothing, filtering, amplification and ridge line extraction is then applied to the image data. Additionally, average processing with respect to multiple fringe lines to produce higher accuracy is successfully applied. Measured values of flying height and pitch and roll displacements are confirmed to be in good accordance with the calculation results, demonstrating excellent applicability of the present method down to the near-contact region.

Image Processing Techniques Applied to Enhancement of Holographic Fringe Patterns

1996 ◽  
Vol 25 (1) ◽  
pp. 61-68
Author(s):  
A. G. Khadakkar ◽  
R. Madhana Sundari ◽  
R. Narayanan
Keyword(s):  
Image Processing ◽  
Image Processing Techniques ◽  
Fringe Patterns ◽  
Processing Techniques

scholarly journals Effect of Surface Roughness on Ultrasonic Testing of Back-Surface Micro-Cracks

2018 ◽  
Vol 8 (8) ◽  
pp. 1233 ◽  
Author(s):  
Zhe Wang ◽  
Ximing Cui ◽  
Hongbao Ma ◽  
Yihua Kang ◽  
Zhiyang Deng
Keyword(s):  
Surface Roughness ◽  
Ultrasonic Testing ◽  
Amplitude Ratio ◽  
Ultrasonic Inspection ◽  
Front Surface ◽  
Signal Amplitude ◽  
Back Surface ◽  
Element Analysis ◽  
Arithmetic Average ◽  
Micro Cracks

Surface roughness is one of the main factors that affect the ultrasonic testing of micro-cracks. This article theoretically analyzes the relationship between the changes in the energy intensity of crack echo waves and roughness-modified transmission coefficients. A series of simulations are carried out using two-dimensional sinusoidal curves as rough surface. Then, parallel experiments are performed on sample surfaces with different arithmetic average heights (Ra). The signal amplitude ratio factor (SARF) is defined to assess the ultrasonic detection capacity for micro-cracks. Both finite element analysis and experimental results show that signal amplitude decreases with an increase in Ra, resulting in signal-to-noise ratio loss. Amplitude attenuation caused by the rough back surface is less than that caused by the rough front surface. It is difficult to identify the signal of micro-cracks with a depth less than 400 μm when the Ra of the front surface is larger than 15 μm. Cracks with depths of more than 200 μm can be distinguished when the back-surface roughness is less than 24 μm. Furthermore, the amplitude of the micro-crack signal increases slightly with variation in the horizontal parameter (Rsm). This study provides a valuable reference for the precision evaluation of micro-cracks using ultrasonic inspection.

Average Residual Stresses in Hard Physical Vapor Deposited (PVD) Coatings

2019 ◽  
Vol 799 ◽  
pp. 20-25
Author(s):  
Harri Lille ◽  
Alexander Ryabchikov ◽  
Jakub Kõo ◽  
Valdek Mikli ◽  
Eron Adoberg ◽  
...  
Keyword(s):  
Residual Stresses ◽  
Front Surface ◽  
Back Surface ◽  
Length Variation ◽  
Pvd Coatings ◽  
Cross Sectional ◽  
Average Residual ◽  
Thin Walled ◽  
Compressive Residual Stresses ◽  
Very High

In this study we determined average residual stresses in hard nitride PVD AlCrN, TiAlN and TiCN coatings through simultaneous measurement of length variation in thin-walled tubular substrates and of the curvature of plate substrates. A device for measurement of the length of the tube was developed. Inside the depositing chamber the tube and the plate were fixed parallel in the relation to the axis of the rotating cathode. One batch of plate samples was produced by deposition on front surface (facing the cathode) and the other batch, by deposition on back surface (with back to the cathode). The cross-sectional microstructure and thickness of the coatings were investigated by means of scanning electron microscopy (SEM). The thicknesses of the coatings deposited on front and back surfaces of the plates and on the tube were significantly different. The values of average compressive residual stresses, determined by both methods, were very high irrespective of coating thickness. It was found that the values of compressive residual stresses in the coating were dependent on the shape of the substrate and on its position in the relation to the axis of the rotating cathode.

Anisotropic Thermal Diffusivity of Aligned Multiwalled Carbon Nanotube Arrays

2002 ◽  
Author(s):  
Theodorian Borca-Tasciuc ◽  
Claudiu L. Hapenciuc ◽  
Bingqing Wei ◽  
Robert Vajtai ◽  
Pulickel M. Ajayan
Keyword(s):  
Carbon Nanotube ◽  
Thermal Diffusivity ◽  
Front Surface ◽  
Multiwalled Carbon Nanotube ◽  
Back Surface ◽  
Multiwalled Carbon ◽  
Conduction Model ◽  
Beam Incident ◽  
Order Of Magnitude ◽  
Photothermoelectric Technique

This work employs a photothermoelectric technique to measure the anisotropic thermal diffusivity of an aligned multiwalled carbon nanotube array. A modulated laser beam incident to the front surface of the sample creates a thermal wave which is detected by a fast responding thermocouple formed between the back surface of the sample and the tip of a sharp metallic probe. The anisotropic thermal diffusivity values are obtained by fitting the radial and frequency dependent thermal signals with an anisotropic heat conduction model. The room temperature thermal diffusivity measured perpendicular to the alignment direction is 0.246×10−5m2/s, an order of magnitude smaller than thermal diffusivity along the CNTs alignment direction 4.4×10−5m2/s. However, the thermal diffusivity of the aligned multiwalled CNT is two orders of magnitude smaller than expected for an individual multiwalled CNT.

Efficiency Enhancement of Photovoltaic/Thermal Module Using Front Surface Cooling Technique in Winter and Summer Seasons: An Experimental Investigation

2019 ◽  
Vol 141 (9) ◽  
Author(s):  
Himanshu Sainthiya ◽  
Narendra S. Beniwal
Keyword(s):  
Solar Cell ◽  
Surface Water ◽  
Surface Temperature ◽  
Front Surface ◽  
Climatic Conditions ◽  
Back Surface ◽  
Water Cooling ◽  
Performance Parameters ◽  
Surface Cooling ◽  
Overall Efficiency

This paper presents the effect of the front surface water cooling on performance parameters (solar cell temperature, back surface temperature, outlet water temperature, electrical efficiency, overall efficiency, etc.) of photovoltaic/thermal (PV/T) module in both winter and summer seasons in Indian climatic conditions. A mathematical model of PV/T module considering energy balance equations has also been presented. A comparative analysis of performance parameters obtained analytically and experimentally has also been presented. A fair agreement has also been found between analytical and experimental results which is supported by correlation coefficient of approximately unity and root mean square error of 10–14%. By front surface water cooling, solar cell and back surface temperature of PV/T module have been found to decrease considerably which in turn resulted in enhanced electrical and overall efficiency of module in winter and summer seasons.

Experimental Measurements of Surface Residual Stress Caused by Nano-scale Contact of Rough Surfaces

2003 ◽  
Vol 795 ◽  
Author(s):  
J. Wang ◽  
P. Shrotriya ◽  
H. H. Yu ◽  
K.-S. Kim
Keyword(s):  
Residual Stress ◽  
High Sensitivity ◽  
Front Surface ◽  
Model Analysis ◽  
Aluminum Surface ◽  
Back Surface ◽  
Dislocation Model ◽  
Surface Residual Stress ◽  
Polycrystalline Aluminum ◽  
Nano Scale

ABSTRACTA previous dislocation model analysis predicts that nano-scale contacts of surface steps induce nucleation of dislocations leading to pro-load and anti-load dislocation segregation near the contact surface. Such dislocation segregation generates a sub-layer of tensile residual stress in a much thicker layer of compressive residual stress near the surface. The sub-layer thickness is expected to be about 50 to 100 times the step height. In order to verify the predictions of the model analysis, experiments are carried out on polycrystalline aluminum surface to determine the existence of the tensile sub-layer. The variation of the residual stress along the thickness direction is measured using a newly developed high sensitivity curvature-measurement interferometer. The interferometer measures the curvature change of the back surface of a plate specimen of about 1.9 mm thickness while the contact-loaded front surface is chemically etched. The residual stress distribution measured with sub-nanometer spatial resolution is compared with analytical predictions.

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