In-situ film thickness measurements using acoustic techniques

1991 ◽  
Author(s):  
Sanjay Bhardwaj ◽  
Butrus T. Khuri-Yakub
Keyword(s):  
Film Thickness ◽  
Acoustic Techniques ◽  
Thickness Measurements

Elastohydrodynamie Lubrication of Big-End Bearings Part 2: Ratification

1991 ◽  
Vol 205 (2) ◽  
pp. 107-119 ◽  
Author(s):  
M B Aitken ◽  
H McCallion
Keyword(s):  
Film Thickness ◽  
Close Correlation ◽  
Connecting Rod ◽  
Test Rig ◽  
Collapse Mechanisms ◽  
Minimum Film Thickness ◽  
Inertial Loading ◽  
Film Collapse ◽  
Thickness Measurements

The elastohydrodynamic analysis developed in Part 1 of this work is ratified against previous Ruston and Hornsby big-end studies. Sufficiently close correlation with published in situ film-thickness measurements allows big-end bearing performance to be determined with some confidence; significant new insight was obtained. Elasticity body forces from connecting-rod motion were found to be an integral component of the big-end representation; it is a prevalent misconception that these forces can be neglected from theoretical as well as experimental test-rig works. Film collapse mechanisms, likened to vapour cavitation, were observed in the dynamically loaded elastic bearing; these were not detected in equivalent rigid bearing simulations. Cyclic minimum film thickness was observed during inertial loading, irrespective of gas force loading. Two separate minimum-film conditions were identified: one in the connecting-rod's neck and a second, at higher load, in the rod's cap. The second condition is critical from a design standpoint; significantly thinner films are predicted than by rigid bearing theory.

Planarization Ability of Chemical Mechanical Planarization (Cmp) Processes

1994 ◽  
Vol 337 ◽  
Author(s):  
Matt Stell ◽  
Rahul Jairath ◽  
Mukesh Desai ◽  
Robert Tolles
Keyword(s):  
Film Thickness ◽  
Chemical Mechanical Planarization ◽  
Silica Particles ◽  
The Other ◽  
Ph Values ◽  
Enhanced Solubility ◽  
Experimental Approaches ◽  
Thickness Measurements

ABSTRACTMethods for determining planarization ability of CMP were explored. Options included film thickness measurements of the dielectric over metal and field, TIR measurements using profilometry, and a combination of the two. The attempt to observe the in situ change in the topography was addressed in two distinct experimental approaches. The first approach involved processing wafers for predetermined intervals. The other approach processed different wafers for different amounts of time. The effects of down force and platen rpm on planarization ability were studied using the first approach. Results indicate that planarization is more efficient at higher down forces and higher platen rpm. Slurry property effects were examined using the second method. The planarization ability appears to suffer at elevated pH values. This is attributed to both the enhanced solubility of the silica particles and the dielectric itself.

Capacitive Film Thickness Measurements in a Ventless Aero-Engine Bearing Chamber—Influence of Operating Conditions and Offtake Design

2013 ◽  
Vol 135 (11) ◽  
Author(s):  
Wolfram Kurz ◽  
Klaus Dullenkopf ◽  
Hans-Jörg Bauer
Keyword(s):  
Film Thickness ◽  
Thickness Distribution ◽  
Operating Conditions ◽  
Chamber Pressure ◽  
Shaft Speed ◽  
Suitable Parameter ◽  
Accuracy And Repeatability ◽  
Thickness Measurements ◽  
Engine Bearing

The paper presents results from film thickness measurements in a bearing chamber test rig. The measurements were performed at different operating conditions and with two offtake designs. A discussion of the measurement technique using in situ calibrated capacitive sensors shows good accuracy and repeatability. The film thickness results are first compared to measurements with the same chamber in a vented configuration. The analysis of the measurements at various operating conditions shows a strong influence of the shaft speed, the chamber pressure, and the offtake design. In contrast to that, flow rate and scavenge ratio have only minor influence. Furthermore, the momentum flux of the core air flow is proposed as a suitable parameter with which the influence of shaft speed and pressure can be correlated to the film thickness distribution.

Capacitive Film Thickness Measurements in a Ventless Aero-Engine Bearing Chamber: Influence of Operating Conditions and Offtake Design

2013 ◽  
Author(s):  
Wolfram Kurz ◽  
Klaus Dullenkopf ◽  
Hans-Jörg Bauer
Keyword(s):  
Film Thickness ◽  
Thickness Distribution ◽  
Operating Conditions ◽  
Chamber Pressure ◽  
Shaft Speed ◽  
Suitable Parameter ◽  
Accuracy And Repeatability ◽  
Thickness Measurements ◽  
Engine Bearing

The paper presents results from film thickness measurements in a bearing chamber test rig. The measurements were performed at different operating conditions and with two offtake designs. A discussion of the measurement technique using in-situ calibrated capacitive sensors shows good accuracy and repeatability. The film thickness results are first compared to measurements with the same chamber in a vented configuration. The analysis of the measurements at various operating conditions shows a strong influence of the shaft speed, the chamber pressure, and the offtake design. In contrast to that, flow rate and scavenge ratio have only minor influence. Furthermore, the momentum flux of the core air flow is proposed as a suitable parameter with which the influence of shaft speed and pressure can be correlated to the film thickness distribution.

Confined methane–water interfacial layers and thickness measurements using in situ Raman spectroscopy

Lab on a Chip ◽  
2017 ◽  
Vol 17 (22) ◽  
pp. 3883-3890
Author(s):  
Bruno Pinho ◽  
Yukun Liu ◽  
Benjamin Rizkin ◽  
Ryan L. Hartman
Keyword(s):  
Raman Spectroscopy ◽  
Reynolds Number ◽  
Film Thickness ◽  
In Situ Raman Spectroscopy ◽  
Interfacial Film ◽  
Interfacial Layers ◽  
In Situ Raman ◽  
Thickness Measurements

Layered methane–water interfaces confined in microfluidics and the influence of Reynolds number on interfacial film thickness.

scholarly journals Measuring and inferring the ice thickness distribution of four glaciers in the Tien Shan, Kyrgyzstan

2020 ◽  
pp. 1-18
Author(s):  
Lander Van Tricht ◽  
Philippe Huybrechts ◽  
Jonas Van Breedam ◽  
Johannes J. Fürst ◽  
Oleg Rybak ◽  
...  
Keyword(s):  
Cross Validation ◽  
Thickness Distribution ◽  
Tien Shan ◽  
Ice Thickness ◽  
Ice Volume ◽  
In Situ Data ◽  
Radio Echo Sounding ◽  
Thickness Measurements ◽  
Tien Shan Mountains

Abstract Glaciers in the Tien Shan mountains contribute considerably to the fresh water used for irrigation, households and energy supply in the dry lowland areas of Kyrgyzstan and its neighbouring countries. To date, reconstructions of the current ice volume and ice thickness distribution remain scarce, and accurate data are largely lacking at the local scale. Here, we present a detailed ice thickness distribution of Ashu-Tor, Bordu, Golubin and Kara-Batkak glaciers derived from radio-echo sounding measurements and modelling. All the ice thickness measurements are used to calibrate three individual models to estimate the ice thickness in inaccessible areas. A cross-validation between modelled and measured ice thickness for a subset of the data is performed to attribute a weight to every model and to assemble a final composite ice thickness distribution for every glacier. Results reveal the thickest ice on Ashu-Tor glacier with values up to 201 ± 12 m. The ice thickness measurements and distributions are also compared with estimates composed without the use of in situ data. These estimates approach the total ice volume well, but local ice thicknesses vary substantially.

In Situ Diagnostics of Vuv Laser Cvd of Semiconductor Interfaces by Ftir Spectroscopy and Spectroscopic Ellipsometry

1995 ◽  
Vol 397 ◽  
Author(s):  
M. Barth ◽  
J. Knobloch ◽  
P. Hess
Keyword(s):  
Film Thickness ◽  
Bulk Material ◽  
Substrate Surface ◽  
Cluster Formation ◽  
Interface Layer ◽  
Native Oxide ◽  
Initial Growth ◽  
Difference Spectra ◽  
Si Substrates

ABSTRACTThe growth of high quality amorphous hydrogenated semiconductor films was explored with different in situ spectroscopic methods. Nucleation of ArF laser-induced CVD of a-Ge:H on different substrates was investigated by real time ellipsometry, whereas the F2 laser (157nm) deposition of a-Si:H was monitored by FTIR transmission spectroscopy. The ellipsometric studies reveal a significant influence of the substrate surface on the nucleation stage, which in fact determines the electronic and mechanical properties of the bulk material. Coalescence of initial clusters occurs at a thickness of 16 Å for atomically smooth hydrogen-terminated c-Si substrates, whereas on native oxide covered c-Si substrates the bulk volume void fractions are not reached until 35 Å film thickness. For the first time we present a series of IR transmission spectra with monolayer resolution of the initial growth of a-Si:H. Hereby the film thickness was measured simultaneously using a quartz crystal microbalance with corresponding sensitivity. The results give evidence for cluster formation with a coalescence radius of about 20 Å. Difference spectra calculated for layers at different depths with definite thickness reveal that the hydrogen-rich interface layer stays at the substrate surface and does not move with the surface of the growing film. The decrease of the Urbach energy switching from native oxide to H-terminated substrates suggests a strong influence of the interface morphology on the bulk material quality.

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