• Transactions of the Korean hydrogen and new energy society
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• v.7 no.2
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• pp.181-191
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• 1996

Samples with the compositions of Mg-10wt.%Ni and Mg-25wt.%Ni were prepared by mechanical alloying in a planetary mill. $Mg_2Ni$ phase was formed in the mixture with hydriding dehydriding cycling. The activation of Mg-10wt.%Ni and Mg-25wt.%Ni was completed after n=7 and n=6 around, respectively, at 583K, $0{\sim}8barH_2$. Mg-10wt.% Ni and Mg-25wt. %Ni are considered as excellent hydrogen-storage materials with very high hydriding rates, high dehydriding rates and relatively large hydrogen-storage capacity. The effets of mechanical alloying and hydriding dehydriding cycling are considered the augmentation in the density of active nucleation sites and the diminution in the particle size.

• Journal of the Korean Institute of Gas
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• v.18 no.5
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• pp.40-46
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• 2014

The hydrogen embrittlement degree of 5 type high strength DP steel charged with hydrogen by electrochemical method was evaluated by small punch test(SP test). After SP test, SP absorbed energy was remarkably decreased from 363 kgf-mm to 209 kgf-mm with increasing hydrogen charging time from 5hr to 50hr at DP5 specimen under the $200mA/cm^2$ current density condition. It was investigated that the decrease of hydrogen charging amount and SP absorbed energy according to the increase of current density and hydrogen charging time had a linear relationship. And it also investigated that the change of bulb height appeared by the SP test was decreased from 1.79mm to 1.59mm with the hydrogen charging conditions. It was supposed that it could be used as indicator of the evaluation of hydrogen embrittlement because of the similar trend of the formal results of SP absorbed energy. From the SEM observation of fracture area by crack in bulb, the morphology of fracture surface according to increasement of the hydrogen charging amount was varied with the cleavage mode.

• Transactions of the Korean hydrogen and new energy society
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• v.20 no.2
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• pp.168-178
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• 2009

To check feasibility of SEWGS(Sorption Enhanced Water Gas Shift) system, conceptual design and sensitivity analysis of operating variables have been investigated based on a design program of two-interconnected fluidized bed. Based on the conceptual design results, the optimum configuration for SEWGS was considered. Among three configurations, bubbling beds system was selected as the best configuration. Process design results indicate that the SEWGS system is compact and feasible. Based on the selected operating conditions, the effects of variables such as pressure, $CO_2$ capture capacity, solid inventory, CO conversion and $CO_2$ capture efficiency have been investigated as well.

• Transactions of the Korean hydrogen and new energy society
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• v.18 no.1
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• pp.1-11
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• 2007

To check feasibility of SMART(Steam Methane Advanced Reforming Technology) system, conceptual design and sensitivity analysis of operating variables have been performed based on the design program of two-interconnected fluidized beds. Among three configurations of two-interconnected fluidized beds systems, the bubbling-bubbling system was selected as the best configuration. Process design results indicate that the SMART system is compact and feasible. Based on the selected operating conditions, the effects of variables such as process capacity, pressure, and weight percent of $CO_2$ absorbable component have been investigated as well.

• Proceedings of the Materials Research Society of Korea Conference
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• 2005.05a
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• pp.150-150
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• 2005

• Korean Journal of Optics and Photonics
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• v.19 no.1
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• pp.54-59
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• 2008

We report on the measurements of absorption spectra from acetylene ($^{12}C_2H_2$) and hydrogen cyanide ($H^{13}C^{14}N$) for wavelength reference in the C-band (conventional band) region using a supercontinuum optical source generated from a mode-locked $Cr^{4+}$:YAG laser. The center wavelength of the mode-locked $Cr^{4+}$:YAG laser was 1510 nm and the pulse duration was 75 fs at 100 MHz repetition rate. The supercontinuum source achieved a flatness of ${\pm}5dB$ over a wavelength range of more than 400 nm, using a 20 m long photonic crystal fiber. The measured absorption spectra from acetylene ($^{12}C_2H_2$) and hydrogen cyanide ($H^{13}C^{14}N$) had more than 50 lines and were analyzed for wavelength standardization.

• The Bulletin of The Korean Astronomical Society
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• v.35 no.1
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• pp.88.2-88.2
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• 2010

2006년 2월 7일, Gemini North Observatory의 Near-Infrared Integral Field Spectrometer (NIFS)를 사용해 타이탄의 K-band 분광영상을 얻었다. NIFS의 파장분해능은 R~5,000이었고, 타이탄 disk의 적도부분은 약 16 pixel로 분해되었다. 2.0 - 2.1 micron 영역에서 미지의 분광선이 관측됐는데, 그 분광 구조는 전형적인 slightly asymmetric-top molecule의 rotational-vibrational 밴드 구조와 유사하게 나타났다. 또한 N2-N2 Collision-Induced Absorption (CIA)과 H2-N2 dimer에 의한 흡수와 메탄(CH4)가스 흡수를 포함한 분광모델을 만들어 비교한 결과 이 파장영역에는 이러한 흡수선들의 영향이 적은 것으로 확인됐다. 따라서 해당 영역의 저분산 (R~2,000 - 3,400) 스펙트럼을 토대로 액체 또는 고체 상태의 탄화수소가 타이탄에 존재한다고 보는 최근 발표된 주장들은 (e.g., Brown et al. 2008, Nature, v. 454, p. 607; Adamkovics et al. 2009, Planetary and Space Science, v. 57, p. 1586) 보다 신중히 고려돼야 한다.

• Transactions of the Korean hydrogen and new energy society
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• v.28 no.6
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• pp.729-737
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• 2017

The measurement accuracy of Tunable Diode Laser Absorption Spectroscopy based Tomography (TDLAST) for the temperature and concentration fields are dependant upon the arrangement method of the used laser beams. This paper reports on the optimization of laser beam arrangements using phantom data. It has been verified that the measurement error of the TDLAST decreased with increase of laser beam numbers. Further, it has been confirmed that perpendicular arrangements between the horizontal and the vertical laser beams without additional diagonal laser beams shows the minimum measurement errors.

• Transactions of the Korean hydrogen and new energy society
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• v.27 no.6
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• pp.773-782
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• 2016

The performance of the CT-TDLAS (computed tomography-tunable diode laser absorption spectroscopy) is strongly dependent upon the line broadening functions. The line of the laser beam used in the TDLAS is scattered by the natural broadening, the collisional broadening and the doppler broadening. The influence of the natural broadening to the experimental spectra obtained in the TDLAS is negligible. The influences of the collisional broadening and the doppler broadening to the experimental spectra are relatively large, in high pressure gas flows and in high temperature low pressure gas flows, respectively. In this study, optimal coefficients are proposed for the doppler broadening function by using the experimental data obtained in a flat burner test. The optimal coefficients were ${\gamma}_j=0.16$ and n=0.37. Using these coefficients, the temperature and concentration distributions at the engine exhaust gas pipe have been calculated showing their validities.

• Transactions of the Korean hydrogen and new energy society
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• v.27 no.5
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• pp.562-570
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• 2016

At the carbon dioxide capture process using the aqueous amine solution, degradation of absorbents is main factor to reducing the process performance. Also, degradation mechanism of absorbent is important for understanding the environmental risk, route of degradation products, health risk etc. In this study, the degradation products of MEA were studied to clarify mechanism in thermal degradation process. The degradation products were analyzed using a $^1H$ NMR (nuclear magnetic resonance) and $^{13}C$ NMR. The analysis methods used in this study provide guidelines that could be used to develop a degradation inhibitor of absorbent and a corrosion inhibitor.