Using a stabilized diode-laser spectrometer, we have studied the line profiles of water vapor near 7185.59 cm(-1). With low pressures of pure gas (=1,Torr) in a White-type cell, we have deduced the line intensities using the Voigt profile. This study shows clear differences between experimental and calculated lines described by a Voigt profile when the pressure increases. For water vapor in mixtures with N(2), O(2), Ar, or He, we have determined the collisional broadening coefficients, taking into account the collisional narrowing (Dicke effect). The narrowing parameters have been determined using soft (Galatry) or hard (Rautian and Sobel'man) collision models and compared to the dynamic friction coefficient. Copyright 2001 Academic Press.
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http://dx.doi.org/10.1006/jmsp.2001.8372 | DOI Listing |
Appl Spectrosc
January 2025
School of Mathematics Physics and Finance, Anhui Polytechnic University, Wuhu, China.
A compact dual-gas sensor based on the two near-infrared distributed feedback diode lasers and a multipass cell has been established for the simultaneous measurement of methane (CH) and acetylene (CH). The time division multiplexing calibration-free direct absorption spectroscopy is used to eliminate the cross interference in the application of multicomponent gas sensors. A wavelength stabilization technique based on the proportion integration differentiation feedback control is developed to suppress laser wavelength drift and an H-infinity (H) filter algorithm to reduce the system noise.
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December 2024
Department of Mechanical Engineering, Stanford University, Stanford, CA 93405, USA.
Distributed feedback lasers, which feature rapid wavelength tunability, are not presently available in the yellow and orange spectral regions, impeding spectroscopic studies of short-lived species that absorb light in this range. To meet this need, a rapidly tunable laser system was constructed, characterized, and demonstrated for measurements of the NH radical at 597.4 nm.
View Article and Find Full Text PDFPLoS One
December 2024
Department of Biomechanical Engineering, Faculty of Mechanical Engineering, Delft University of Technology, Delft, The Netherlands.
The demographic shift has increased the demand for surgical interventions to address age-related degenerative diseases, such as spinal fusion. Accurate placement of pedicle screws, crucial for successful spinal fusion, varies widely with physician experience. Integrating tissue sensing into spine surgical instruments allows intraoperative examination of tissue properties, providing surgeons with additional information to prevent screw misplacement.
View Article and Find Full Text PDFNanomaterials (Basel)
November 2024
School of Material Science and Engineering, Pusan National University, Busan 46241, Republic of Korea.
The rapid evolution of microelectronics and display technologies has driven the demand for advanced manufacturing techniques capable of precise, high-speed microchip transfer. As devices shrink in size and increase in complexity, scalable and contactless methods for microscale placement are essential. Laser-induced forward transfer (LIFT) has emerged as a transformative solution, offering the precision and adaptability required for next-generation applications such as micro-light-emitting diodes (μ-LEDs).
View Article and Find Full Text PDFSpectrochim Acta A Mol Biomol Spectrosc
December 2024
College of Physics and Electronic Engineering, Jiangsu Normal University, Xuzhou 221116, PR China. Electronic address:
Accurate determination of spectral parameters for carbon monoxide (CO) transitions is crucial for the development of laser absorption spectroscopy-based CO sensors. This study reports the measurement of line strengths, self-broadening coefficients, and their temperature-dependent exponents for three transitions in the first overtone band near 2.3 μm.
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