Study of Polyphenyl Ether Fluid (5P4E) in Operating Elastohydrodynamic Contacts by Infrared Emission Spectroscopy

1979 ◽  
Vol 101 (1) ◽  
pp. 67-73 ◽  
Author(s):  
J. L. Lauer
Keyword(s):  
Emission Spectroscopy ◽  
Emission Spectra ◽  
Elastic Solid ◽  
Infrared Emission ◽  
Operating Conditions ◽  
Sliding Contact ◽  
Critical Shear Rate ◽  
Shear Rates ◽  
Polyphenyl Ether ◽  
High Shear Rates

Infrared emission spectra of 5P4E polyphenyl ether were obtained from an operating elastohydrodynamic sliding contact at different speeds and loads by Fourier emission microspectrophotometry. The spectra were found to be polarized with respect to the direction of the conjunction line, especially at high shear rates. Film and metal surface temperatures were calculated from the spectra, and film thicknesses were determined under various operating conditions. Changes of polarized band structure above a critical shear rate, at which the slope of the film temperature versus shear curve changes abruptly and at which the film thickness assumes a minimum value, are consistent with a transition of the lubricant from a viscous liquid to a visco-elastic liquid or to an elastic solid.

Infrared Emission Spectroscopy as a Reliability Tool

1999 ◽  
Author(s):  
Q. Kim ◽  
S. Kayali
Keyword(s):  
Spatial Resolution ◽  
Emission Spectroscopy ◽  
Hot Spot ◽  
Cost Effective ◽  
Infrared Emission ◽  
Test System ◽  
Operating Conditions ◽  
Yield Enhancement ◽  
Infrared Emission Spectroscopy ◽  
Channel Temperature

Abstract In this paper, we report on a non-destructive technique, based on IR emission spectroscopy, for measuring the temperature of a hot spot in the gate channel of a GaAs metal/semiconductor field effect transistor (MESFET). A submicron-size He-Ne laser provides the local excitation of the gate channel and the emitted photons are collected by a spectrophotometer. Given the state of our experimental test system, we estimate a spectral resolution of approximately 0.1 Angstroms and a spatial resolution of approximately 0.9 μm, which is up to 100 times finer spatial resolution than can be obtained using the best available passive IR systems. The temperature resolution (<0.02 K/μm in our case) is dependent upon the spectrometer used and can be further improved. This novel technique can be used to estimate device lifetimes for critical applications and measure the channel temperature of devices under actual operating conditions. Another potential use is cost-effective prescreening for determining the 'hot spot' channel temperature of devices under normal operating conditions, which can further improve device design, yield enhancement, and reliable operation. Results are shown for both a powered and unpowered MESFET, demonstrating the strength of our infrared emission spectroscopy technique as a reliability tool.

Temperature Gradients Through EHD Films and Molecular Alignment Evidenced By Infrared Spectroscopy

1981 ◽  
Vol 103 (1) ◽  
pp. 65-73 ◽  
Author(s):  
V. W. King ◽  
J. L. Lauer
Keyword(s):  
Absorption Spectrum ◽  
Emission Spectra ◽  
Infrared Emission ◽  
Molecular Alignment ◽  
Temperature Gradients ◽  
Spectral Change ◽  
Continuum Source ◽  
Polyphenyl Ether ◽  
Elementary Analysis ◽  
Gap Width

Partial and complete emission band reversals have been observed in the infrared emission spectra from portions of operating sliding contacts. An elementary analysis has been carried out to show that partial reversals are due to temperature gradients in the fluid film—the film acts both as a radiation-emitter and absorber, and that total reversals—an emission spectrum appears as an absorption spectrum—are likely to be due to a continuum source, such as hot solid asperities. The total energy radiated under the latter conditions exceeds that under the others. A decrease in gap width with increased load was accompanied by a dramatic spectral change in the case of 5P4E polyphenyl ether, which is indicative of molecular alignment.

Continuous-Wave CO2 Laser-Excited Infrared Emission Spectroscopy

1987 ◽  
Vol 41 (6) ◽  
pp. 1009-1019 ◽  
Author(s):  
H. H. Belz ◽  
H. Gutberlet ◽  
B. Schallert ◽  
B. Schrader
Keyword(s):  
Raman Spectroscopy ◽  
Thermal Equilibrium ◽  
Emission Spectroscopy ◽  
Continuous Wave ◽  
Emission Spectra ◽  
Infrared Emission ◽  
Temperature Profiles ◽  
Molecular Gases ◽  
Cw Laser ◽  
Potential Applications

Radiation of a cw CO2 laser can be used to excite infrared emission spectra of nearly all molecular gases by adding small amounts of SF6 as a sensitizer. These emission spectra show a thermal equilibrium between vibrational, rotational, and translational states with temperatures up to 1200 K. Temperature profiles of these gases about a focused cw CO2 laser beam are analyzed by Raman spectroscopy. The detection of small amounts of sample and investigations of cw laser-induced chemical reactions are interesting potential applications.

Remote Monitoring of a Multi-Component Liquid-Phase Organic Synthesis by Infrared Emission Spectroscopy: The Recovery of Pure Component Emissivities by Band-Target Entropy Minimization

2007 ◽  
Vol 61 (10) ◽  
pp. 1057-1062 ◽  
Author(s):  
Shuying Cheng ◽  
Martin Tjahjono ◽  
D. Rajarathnam ◽  
Li Chuanzhao ◽  
Ilya Lyapkalo ◽  
...  
Keyword(s):  
Liquid Phase ◽  
Emission Spectroscopy ◽  
Cycloaddition Reaction ◽  
Emission Spectra ◽  
Infrared Emission ◽  
Pure Component ◽  
Reconstruction Technique ◽  
Infrared Emission Spectroscopy ◽  
Entropy Minimization ◽  
Ft Ir

A liquid-phase cycloaddition reaction near ambient temperature involving dimethyl acetylenedicarboxylate (DMAD) and cyclopentadiene (CP) as reactants was measured using a conventional Fourier transform infrared (FT-IR) spectrometer with an emission accessory. Two semi-batch experiments were performed and a total of 55 spectra were collected using a DTGS detector. Band-target entropy minimization (BTEM), a pure component spectral reconstruction technique, was applied to analyze the data set to retrieve the pure component emission spectrum from the reaction system. The estimated emission spectra of the solvent chloroform, DMAD, CP, and product, namely dimethyl bicyclo[2.2.1]-2,5-heptadiene-2,3-dicarboxylate, were all reconstructed with rather good quality. The estimated emission spectra are similar to independent FT-IR spectra of the same cycloaddition reaction. Using a least squares fit, the relative concentration profiles of the species are obtained. Because this appears to be the first time that a liquid-phase reaction has been monitored by infrared emission spectroscopy, further improvements and opportunities for general multi-phase liquid reaction monitoring are discussed.

Surface Analysis with FT-IR Emission Spectroscopy

1992 ◽  
Vol 46 (5) ◽  
pp. 811-818 ◽  
Author(s):  
David H. Sullivan ◽  
W. Curtis Conner ◽  
Michael P. Harold
Keyword(s):  
Solid State ◽  
Sample Preparation ◽  
Surface Analysis ◽  
Emission Spectroscopy ◽  
Diffuse Reflectance Spectroscopy ◽  
Emission Spectra ◽  
Infrared Emission ◽  
Copper Plate ◽  
Analysis Tool ◽  
Emission Analysis

The technique of infrared emission spectroscopy (IRES) is reviewed and further examined in this study as a surface analysis tool. A system has been designed which allows simultaneous kinetic and in situ infrared emission analysis of catalyst surfaces. IRES spectra of several gas mixture/solid systems are obtained in order to examine sample preparation and spectra processing issues; these systems include Pt/Al2O3 exposed to CO and CO-NO mixtures, an oxidized copper plate, and a zeolite exposed to inert atmospheres. For the temperature range of importance to catalysis (300–600 K), IRES is limited to frequencies less than 2500 cm−1. However, IRES is especially well suited for studying solid-state vibrational modes (<1000 cm−1). Moreover, IRES allows catalyst samples to be studied without dilution or extensive sample preparation. The thin samples required for IRES make it possible to study both surface adsorbate and the solid-state lattice vibrations simultaneously. This information can provide useful insight into the interpretation of kinetic data of reactions on metal oxide catalysts. However, samples which are too thick or are supported on a high-emissivity surface will not yield satisfactory spectra. Two correction techniques are examined which reduce background and sample-reflectance effects in the emission spectra. Some of the IRES data are compared to the corresponding spectra obtained by transmission and diffuse-reflectance spectroscopy. IRES is shown to be competitive with these more popular techniques for IR surface analysis.

Infrared Emission Spectra of Elastohydrodynamic Contacts

1976 ◽  
Vol 98 (2) ◽  
pp. 230-235 ◽  
Author(s):  
J. L. Lauer ◽  
M. E. Peterkin
Keyword(s):  
Contact Region ◽  
Radiant Energy ◽  
Emission Spectra ◽  
Infrared Emission ◽  
Operating Conditions ◽  
Test Fluid ◽  
Two Fluids ◽  
Spectral Bands ◽  
Ball Surface ◽  
Lower Fluid

A small diamond disk mounted as a window in a steel plate was covered with test fluid, and a weighted steel ball was rotated over the window so as to form a sliding elastohydrodynamic (EHD) contact region. Some of the radiant energy generated in this region, both in the fluid and at the boundaries, passed through the window into an infrared interferometer, giving rise to an emission spectrum. This spectrum could be separated into contributions from the fluid and from the ball surface, making it possible, by appropriate calibrations, to estimate their temperatures separately under operating conditions. Moreover, the shape of the discrete spectral bands of the fluid permitted some inferences on its state. Two fluids were studied under identical mechanical conditions, a polyester and a naphthenic oil, each containing an equal amount of polymethylstyrene as a spectral indicator. Differences of band intensity, band width, and frequency could, therefore, be attributed to differences in the behavior of the base fluid. The principal results were much lower fluid temperatures and lower metal surface temperatures when the polyester was used than when the naphthenic oil was similarly used. Polyester films were also thicker and of higher density than naphthenic oil films under the same conditions. This work is only the beginning of a comprehensive study of EHD contacts by infrared spectroscopy, but the results already achieved lead to interesting speculations on the mechanisms of EHD processes, which further study is expected to elucidate.

Infrared Emission Spectroscopy Applied to the Oxidation of Molybdenum

1978 ◽  
Vol 32 (3) ◽  
pp. 310-316 ◽  
Author(s):  
L. M. Gratton ◽  
S. Paglia ◽  
F. Scattaglia ◽  
M. Cavallini
Keyword(s):  
Sample Preparation ◽  
Absorption Spectra ◽  
Emission Spectroscopy ◽  
Emission Spectra ◽  
Infrared Emission ◽  
Molybdenum Oxides ◽  
Spectroscopy Technique ◽  
Infrared Emission Spectroscopy ◽  
Emission And Absorption Spectra ◽  
Absorption Technique

The present work points out the utility of infrared emission spectroscopy as applied to the study of the oxidation of metal surfaces. It is shown that good results can be achieved even with standard dispersion spectrophotometers. The work shows emission spectra obtained at a temperature of only 133°C from samples of about 380 A thickness and 2 cm2 area. The molybdenum oxides are particularly useful to test the capability of the infrared emission spectroscopy technique. The study of the behavior of the emission bands and the differences between the emission and absorption spectra show that this technique cannot only be an alternative to absorption spectroscopy, but also can give different data from those which can be achieved by the absorption technique. Spectra are recorded directly on the oxidizing sample. The increase in intensity and the change in the shape of the bands are monitored while the oxidation is performed. It is noted that with infrared emission spectroscopy, sample preparation is greatly simplified.

FT-IR Emission Spectroscopy and its Applications

1993 ◽  
Vol 47 (9) ◽  
pp. 1446-1451 ◽  
Author(s):  
János Mink ◽  
Gábor Keresztury
Keyword(s):  
Emission Spectroscopy ◽  
Emission Spectra ◽  
Infrared Emission ◽  
Metal Powders ◽  
Adsorbed Species ◽  
Infrared Emission Spectroscopy ◽  
Recent Developments ◽  
Ft Ir ◽  
Ir Emission

The practical aspects of infrared emission spectroscopy are reviewed briefly, with emphasis on recent developments and on special problems encountered in measurements of adsorbed species on opaque substrates. A few examples are given for cases when the species of interest give rise to inverted emission bands on the background of substrate emission. The feasibility of recording IR emission spectra of adsorbates on metal powders is demonstrated.

Quantitative Infrared Emission Spectroscopy of Phosphosilicate Glass on Silicon Wafers Using Multivariate Calibration

1992 ◽  
Vol 46 (2) ◽  
pp. 340-344 ◽  
Author(s):  
B. Wangmaneerat ◽  
J. A. McGuire ◽  
T. M. Niemczyk ◽  
D. M. Haaland ◽  
J. H. Linn
Keyword(s):  
Emission Spectroscopy ◽  
Multivariate Calibration ◽  
Emission Spectra ◽  
Infrared Emission ◽  
Silicon Wafers ◽  
Dielectric Thin Film ◽  
Infrared Emission Spectroscopy ◽  
Single Beam ◽  
Calibration Methods ◽  
Phosphosilicate Glass

Phosphosilicate glass (PSG) is widely used in the microelectronics industry as a dielectric thin film. Determination of phosphorus concentration in these films is important for quality control. Data are presented here indicating that infrared emission spectroscopy combined with multivariate calibration can produce concentration determinations with a precision comparable to that of the electron microprobe reference method. Partial least-squares multivariate calibration methods applied to infrared emission spectra of twelve calibration standards of PSG films on silicon wafers at 225°C yielded a cross-validated standard error of prediction of 0.11 wt % P. It was found that the precisions of the phosphorus determinations were comparable for the use of absorbance spectra, single-beam emission spectra, or single-beam emission spectra ratioed to a blackbody at the same temperature.

Asialo von Willebrand Factor Enhances Platelet Adhesion to Vessel Subendothelium

1988 ◽  
Vol 60 (01) ◽  
pp. 030-034 ◽  
Author(s):  
Eva Bastida ◽  
Juan Monteagudo ◽  
Antonio Ordinas ◽  
Luigi De Marco ◽  
Ricardo Castillo
Keyword(s):  
Von Willebrand Factor ◽  
Platelet Adhesion ◽  
Human Albumin ◽  
Membrane Receptors ◽  
Shear Rates ◽  
High Shear Rates ◽  
Platelet Deposition ◽  
Platelet Spreading ◽  
Von Willebrand ◽  
Willebrand Factor

SummaryNative von Willebrand factor (N-vWF) binds to platelets activated by thrombin, ADP or ristocetin. Asialo vWF (As-vWF) induces platelet aggregation in absence of platelet activators. N-vWF mediates platelet adhesion to vessel subendothelium at high shear rates. We have investigated the role of As-vWF in supporting platelet deposition to rabbit vessel subendothelium at a shear rate of 2,000 sec-1, using the Baumgartner perfusion system. We have studied the effects of the addition of As-vWF (from 2 to 12 μg/ml) to perfusates consisting of washed red blood cells, 4% human albumin and washed platelets. Our results show a significant increase in platelet deposition on subendothelium (p <0.01) in perfusions to which As-vWF had been added. Blockage of the platelet glycoproteins Ib and IIb/IIIa (GPIb and GPIIb/IIIa) by specific monoclonal antibodies (LJIb1 and LJCP8, respectively) resulted in a decrease of platelet deposition in both types of perfusates prepared with N-vWF and As-vWF. Our results indicate that As-vWF enhances platelet deposition to vessel subendothelium under flow conditions. Furthermore, they suggest that this effect is mediated by the binding of As-vWF to platelet membrane receptors, which in turn, promote platelet spreading and adhesion to the subendothelium.

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