• Tuberculosis and Respiratory Diseases
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• 제56권6호
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• pp.571-584
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• 2004

Magnetic Resonance Imaging (MRI) is one of the most advanced imaging techniques in clinical and research medicine. However, clinical application of MRI to the lung or thorax has been limited due to various drawbacks. Low signal intensity of the lung and cardiac and respiratory movements are the most serious problems with MRI in thorax. Nevertheless, MRI is superior to CT in some selected patients with thoracic diseases. The role of clinical MRI in thoracic disease has been widened with improvement of MR equipments and development of new pulse sequences. Otherwise, functional assessment of lung by MRI has been studied for the last decade. These include perfusion MRI with or without contrast enhancement and ventilation MRI with oxygen-enhancement or hyperpolarized noble gas, $^3He$ and $^{129}Xe$.

• 원예과학기술지
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• 제29권4호
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• pp.382-387
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• 2011

The chemical composition of essential oils obtained from aerial parts in spearmint, apple mint and chocolate mint, was investigated by gas chromatography/mass spectrometry analyses. (-)-Carvone (33.0%) was quantitatively major compound in spearmint, followed by R-(+)-limonene (11.7%) and ${\beta}$-phellandrene (9.7%); (-)-carvone (37.4%) and germacrene D (11.9%) in apple mint; and (-)-menthol (34.3%), p-menthone (18.4%) and menthofuran (9.8%) in chocolate mint. Hierarchical cluster analysis and principle components analysis showed the clear difference in chemical composition of the three mint oils.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 2004년도 춘계학술대회 학술발표 논문집 제14권 제1호
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• pp.438-441
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• 2004

In this study, we introduce a noble neurogenetic approach to the design of fuzzy controller. The design procedure dwells on the use of Computational Intelligence (CI), namely genetic algorithms and Fuzzy-Set based Neural Networks (FSNN). The crux of the design methodology is based on the selection and determination of optimal values of the scaling factors of the fuzzy controllers, which are essential to the entire optimization process. First, the tuning of the scaling factors of the fuzzy controller is carried out by using GAs, and then the development of a nonlinear mapping for the scaling factors is realized by using GA based FSNN. The developed approach is applied to a nonlinear system such as an inverted pendulum where we show the results of comprehensive numerical studies and carry out a detailed comparative analysis.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 C
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• pp.1700-1702
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• 1996

Solid oxide fuel cell(SOFC) is an electrochemical energy device which converts the free energy of fuel gas directly to electric energy. SOFC has several diratinct advantages over other types of fuel cells: no use of noble metals, no requirement of a reformer, no problem of liquid electrolyte management, and no problem of corrosion by liquid electrolyte. In this study, we have investigated the cell components and the single cell of the planar SOFC fabricated by composite plate process, in which green films of electrolyte, anode and cathode were co-fired. The planar SOFCs were tested and the cell performance characteristics wag evaluated by using electrochemical methods.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.371.2-371.2
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• 2014

가스 센서분야에서 특정 가스종에 대한 선택성과 감응도 향상을 위해 금속 촉매 등을 센서 물질 표면이나 내부 등에 형성시키는 방안이 많이 연구되고 있다. 1차원 구조 반도성 물질인 나노섬유 내에 금속 촉매를 형성시켜 특정 가스에 대한 선택성과 감응도를 향상시키는 연구가 보고된 바 있다. 선행연구에 의하면 Au와 Pt입자가 형성된 나노섬유의 경우, 각각 CO와 toluene가스에 대하여 선택적인 감응을 나타내는 것으로 확인되었다. 본 연구에서는 전기방사법과 광환원법을 동시에 이용하여 Au와 Pt 입자가 포함된 $SnO_2$ 나노섬유를 합성하고, 이들 나노섬유의 가스감응 특성을 연구하였다.

• 한국대기환경학회지
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• 제6권1호
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• pp.57-72
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• 1990

The oxidation of carbon monoxide on a catalyst, $LaSrNiCoO_3$ was investigatigated with a plug flow system. Kinetic quantities such as reaction-rate, reaction order and Arhenius-parameters at various reactor temperature from 200$^\circ$C to 300$^\circ$C were determined. Also, the optimum condition for the oxidation of carbon monoxide with this catalyst was determined and are as follows. Partial pressure of oxigen ; 428mmHg Partial pressure of carbon monoxide ; 332mmHg Mixed moral ratio of oxigen and Carbon monoxide ; 1.3 : 1 Total gas flow ; 224ml/min Reaction temperature ; 340$^\circ$C The reaction kinetic equation at the optimum condition, temperature range from 200$^\circ$C to 340$^\circ$C, are as follow. $$ $v = Ae^{6.5Kcal/RT} [CO]^{0.93 \sim 0.98} [O_2]^{0.42 \sim 0.50}$ $$ In addition to this, numerical calculation were performed to evaluate the mass and heat transfer effect on this system.

• Journal of Advanced Marine Engineering and Technology
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• 제20권4호
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• pp.43-49
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• 1996

With the recent interest in methanol as a SI engine fuel, aldehyde emissions have become a greater concern. A M-90 fueled passenger car was operated in a chassis dynamometer using FTP 75 driving cycle to examine formaldehyde emissions. Formation process of aldehyde and methods to reduce them are discussed in this paper for a SI-engine passenger car operating by M-90. Aldehyde emissions have been found to be 3 to 7 times higher from M-90 than from gasoline, while CO, NOx, THC are as low or lower than gasoline. Noble metal compositions appeared to play a role in formaldehyde and unburned methanol emission performance. For example, catalyst Pd showed better reduction of both formaldehyde and methanol than catalyst Pt. however, emission rates of formaldehyde and methanol for catalyst Pt were relatively similar to catalyst Pt/Rh.

• 한국광학회:학술대회논문집
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• 한국광학회 2008년도 하계학술발표회 논문집
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• pp.157-158
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• 2008

High-order harmonics from gaseous atoms driven by an intense femtosecond laser pulse can form an attosecond pulse train. By selecting suitable harmonic generation conditions, the harmonic spectrum can be broad enough to form sub-hundred attoseconds. One serious limitation, however, comes from the inherent attosecond chirp originating from the harmonic generation process. We have proposed to compensate for the positive attosecond chirp by making use of negative group delay dispersion of a metallic x-ray filter or a noble gas. We generated 241-as pulses from neon and compressed them to 106 as after propagating through argon, close to the transform-limited duration of 98 as.

• 수산해양기술연구
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• 제29권2호
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• pp.124-131
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• 1993

Recently. with the rapid development in large sea water systems. there occurs much interest in the study of erosion-corrosion. In this study. the mild steel(SB41) was tested by using of a erosion-corrosion test apparatus with fountain-jet and was investigated under the environments of liquid, air-liquid 2 phase flow and solid particle-liquid 2 phase flow. Main results obtained are as follows : 1. The weight loss by corrosion-erosion in air-liquid 2 phase flow are more increased than that in only liquid solution. 2. Effect of air-liquid 2 phase flow on corrosion-erosion sensitivity becomes more sensitive in natural seawater than that in distilled water. 3. The corrosion potential by corrosion-erosion in air-liquid and solid particle-liquid 2 phase flow becomes noble than that of only liquid solution.

• Journal of the Korean Physical Society
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• 제73권10호
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• pp.1458-1465
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• 2018

We present a constructed setup for polarizing $^{129}Xe$ noble gas. Hyperpolarized $^{129}Xe$ has been obtained via spin exchange with an optically pumped rubidium vapor. Optical pumping is based on polarizing the valence electron of rubidium by the resonant absorption of a circularly polarized laser light. The magnetic field of 30 G was used for obtaining $^{129}Xe$ polarization. The apparatus for detecting polarization is a nuclear magnetic resonance spectrometer. The highest $^{129}Xe$ polarization of 54% has been obtained using 60 W circularly polarized laser light with wavelength of 794.7 nm. The measured longitudinal relaxation time of the hyperpolarized $^{129}Xe$ was 72.3 minutes.