TDL-based spectroscopy for simultaneous measurement of multiple gas properties using a single absorption line

Hanseul Shim,Gyeongrok Kim,정시온,박기수 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.4

This study presents a single-line absorption spectroscopy method for the simultaneous measurement of gas pressure and temperature through diode laser absorption spectroscopy using a single absorption line. In the proposed method, the absorbance loss of an absorption line that may occur during baseline subtraction is predicted, and the gas properties are determined by matching a calculated absorbance to a recovered absorbance using the predicted loss. To verify the proposed method, gas property measurements are conducted for air conditions with a pressure range of 10-100 kPa and a temperature range of 300-500 K. An absorption line in the oxygen A band is selected to measure the gas properties of air. Using the proposed method, it is confirmed that the gas pressure and temperature could be measured within errors of 25 % and 18 %, respectively. When the gas pressure is predetermined using a pressure gauge, the gas temperature can be measured within an error of 14 %.

실내장식용 섬유소재의 흡음성에 관한 연구

최인려 ( In Ryu Choi ),방혜경 ( Hey Kyong Bang ) 복식문화학회 2012 服飾文化硏究 Vol.20 No.4

The purpose of this study is to help to prevent daily noises by measuring the noise absorption coefficient of the non-woven fabrics and wallpapers which are commonly used in lining and noise absorption coefficient of lining curtain, Seven types of fiber materials for the interior decoration, one non-woven fabric for the wallpaper linings, and two types of textiles for curtain linings are used as the experimental materials in this study. The noise absorption coefficient of the noise absorbents were measured by using impedance tube, And the thermal transmittance were measured by using thermal transmittance Lester. The results of this study are as follows; Observing the noise absorption efficiency of each experimental materials, the combination of fiber materials and linings, the noise absorption efficiency of cotton, polyester and silk were similar and for the experimental materials of flax, rayon, acrylic and nylon were resulted the similar noise absorption efficiency. The result of combination of fiber material and black fabric was highest among the combined linings. For the combination of fiber material and non-woven fabric, double layers of non-woven fabric resulted slightly higher noise absorption coefficient result than single layer of non-woven fabric. The thermal transmittance and the sound absorbents of experimental materials were affected by the thickness, density and layer of air of the experimental materials.

RF Power Absorption Enhancement by Optimization of the Conductive Grid in a Magnetic Composite

Baekil Nam,Jinu Kim,Joonsik Lee,Ki Hyeon Kim IEEE 2014 IEEE transactions on magnetics Vol.50 No.11

<P>Electromagnetic noise suppression was studied by near-field power absorption of a magnetic composite film composed of magnetic fillers and metallic mesh grid in nonmagnetic matrix, which were simulated using a commercial finite-element electromagnetic solver. The geometrical characteristics of the grid on the power absorption were evaluated using the transmission line method with a microstrip line. For conductive grid spacing and the period of lines composing a grid, maximum power absorption was obtained when the width of microstrip signal line was comparable with the grid spacing. The vertical position of the grid in magnetic composite was suggested to be at the center or top position of the composite for higher power absorption. The power absorptions and bandwidth of frequency were enhanced using thin metallic grid on magnetic composite in comparison with that of thick metallic grid.</P>

Yield line mechanism analysis of cold-formed channel sections with edge stiffeners under bending

S. Maduliat,M.R. Bambach,X.L. Zhao 국제구조공학회 2012 Structural Engineering and Mechanics, An Int'l Jou Vol.42 No.6

Cold-formed channel sections are used in a variety of applications in which they are required to absorb deformation energy. This paper investigates the collapse behaviour and energy absorption capability of cold-formed steel channels with flange edge stiffeners under large deformation major-axis bending. The Yield Line Mechanism technique is applied using the energy method, and based upon measured spatial plastic collapse mechanisms from experiments. Analytical solutions for the collapse curve and in-plane rotation capacity are developed, and used to model the large deformation behaviour and energy absorption. The analytical results are shown to compare well with experimental values. Due to the complexities of the yield line model of the collapse mechanism, a simplified procedure to calculate the energy absorbed by channel sections under large bending deformation is developed and also shown to compare well with the experiments.

전송선 이론에 의한 적외선 흡수 구조체의 흡수율 모의시험

박승만(Seung-man Park) 대한전기학회 2013 전기학회논문지 Vol.62 No.12

In this paper, the modeling and simulation of infrared absorption in an infrared absorbing structure with the cascaded transmission line model were carried out. Each layer in the infrared absorbing structure can be modeled as a characteristic impedance of the cascaded transmission line model. The simulation results show that the cavity thickness to get a maximum absorption should be less than a quarter wavelength, which is somewhat different from prevalent thickness. It can be assured that the sheet resistance of an absorbing layer to get a maximum absorption is 377Ω/□, that the thickness of the absorbing layer dose not affect the spectral characteristics of absorption. It is also shown that the thickness of the active layer is not critical to the IR absorption. It can also be assured that the validation of this modeling is proved in comparison with the previous results from similar absorbing structures.

Yield line mechanism analysis of cold-formed channel sections with edge stiffeners under bending

Maduliat, S.,Bambach, M.R.,Zhao, X.L. Techno-Press 2012 Structural Engineering and Mechanics, An Int'l Jou Vol.42 No.6

Cold-formed channel sections are used in a variety of applications in which they are required to absorb deformation energy. This paper investigates the collapse behaviour and energy absorption capability of cold-formed steel channels with flange edge stiffeners under large deformation major-axis bending. The Yield Line Mechanism technique is applied using the energy method, and based upon measured spatial plastic collapse mechanisms from experiments. Analytical solutions for the collapse curve and in-plane rotation capacity are developed, and used to model the large deformation behaviour and energy absorption. The analytical results are shown to compare well with experimental values. Due to the complexities of the yield line model of the collapse mechanism, a simplified procedure to calculate the energy absorbed by channel sections under large bending deformation is developed and also shown to compare well with the experiments.

지구 대기 흡수선 스펙트럼 계산

정광희,한인우,이병철,Jeong, Gwanghui,Han, Inwoo,Lee, Byeong-Cheol 한국천문학회 2014 天文學論叢 Vol.29 No.3

In ground-based astronomical spectroscopic observations, there are many telluric absorption lines that are laid on the spectra of celestial objects. To study the physical properties of the celestial objects with these contaminated spectra, the telluric lines should be removed. A conventional method for removing the telluric lines is using the standard stellar spectrum as telluric line. In this paper, we introduce a technique to calculate synthetic telluric spectra and use them to remove telluric lines from a spectrum of a celestial object. We used Line-by-Line Radiative Transfer Model (LBLRTM) for calculating a synthetic spectrum and selected Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) model as atmospheric model. We apply our method to some spectra obtained by Bohyunsan Observatory Echelle Spectrograph (BOES) to show that the telluric lines are well removed from the observed spectra by our model within an accuracy of 2% which is close to the 1-sigma rms of the original spectra.

A Finite-element Method Analysis of Electromagnetic Noise Absorption in a Coplanar Transmission Line Integrated with a Magnetic Film

Jae Cheon Sohn,Suk Hee Han,Sang Ho Lim 한국자기학회 2006 Journal of Magnetics Vol.11 No.2

A finite-element method is used to analyze loss generation and electromagnetic noise absorption characteristics of a coplanar waveguide transmission line integrated with a magnetic thin film. Parameters used in the analysis are the electrical resistivity of the magnetic layer and the thickness of both magnetic and insulating layers. The results indicate that L-C resonance is the main loss mechanism of the electromagnetic noise absorption.

지구 대기 중 H2O, O2 등가폭의 일중 변화

강동일 한국지구과학회 2010 한국지구과학회지 Vol.31 No.4

The scattered light of solar radiance near the infrared ray area was observed to measure H2O and O2 absorption lines. The changes of H2O and O2 equivalent width were calculated on the basis of the measurement. O2 equivalent width showed negative correlation with the amount of solar radiance; O2 equivalent width had a tendency to diminish as the amount of the solar radiance increased and to increase as the amount of the solar radiance decreased. On the other hand,H2O equivalent width showed the positive correlation with the amount of solar radiance. Especially it was noted that the sum of equivalent width of absorption lines created by H2O and O2 in a day was fairly constant. It is implied that the constant equivalent width is caused by the complementary development of photodissociation and recombination in O2 and H2O. 태양 복사의 지구 대기 산란광을 근 적외선 영역에서 분광 관측하여 H2O와 O2 흡수선을 측정하고 이것으로 태양 복사량에 따른 두 기체의 등가폭 변화를 계산하였다. O2는 태양 복사량이 증가할수록 등가폭이 줄어들고 복사량이감소할수록 커지는 경향을 보였고, H2O는 그 반대의 경향을 보였다. 특히 두 기체가 만드는 흡수선 등가폭의 합은 하루 중에 대체로 일정한 경향을 보였다. 본 연구에서는 이것이 태양광에 의한 광해리와 재결합이 O2와 H2O에 있어서상호 보완적으로 일어나기 때문으로 추측한다.

0.412 MeV 감마선에 대한 원주형 NaI(Tl) 섬광체의 총 절대검출효율 계산

홍권표,신희성,이상윤,노성기 대한방사선 방어학회 2002 방사선방어학회지 Vol.27 No.4

Total absolute detection efficiencies of a 7.62 cm(dia.) and 7.62 cm(height) cylindrical NaI(Tl) crystal have been calculated for 0.412 MeV r -rays from a source(point, circular disk, square and line type). In this calculation the linear energy-absorption coefficients based on Hubbell's data have been considered and then calculated total absolute detection efficiencies compared with those from Grosjean and Bossaert. Besides, the source axis-to-detector axis shift distance which, could give rise to about 0.05% deviation in the total absolute detection efficiencies has been calculated for a line-type source of 0.5 cm in its length when a source-to-detector distance is 5 cm. It is revealed that the total absolute detection efficiencies obtained in this study are considerably different from those of Grosjean and Bossaert. In addition it is found that the deviation induced due to an imperfect center of a line type source may be within 0.05% if the shifted discrepancy is no larger than 1.74mm.