Effects of Passages on the Extracellular Matrix Synthesis by Cultured Ret Mesangial Calls

Park, Jung Sik,Kim, Soon Bae,Kang, Jae Young,Yong, Won Seok,Park, Su-Kil,Hong, Changgi D .,Kang, Sin Ae 대한신장학회 1994 Kidney Research and Clinical Practice Vol.13 No.3

바이오가스의 성분 변화가 엔진 성능에 주는 영향

박승현(Seunghyun Park),박철웅(Cheolwoong Park),김영민(Youngmin Kim),이선엽(Sunyoup Lee),김창기(Changgi Kim) 한국가스학회 2011 한국가스학회지 Vol.15 No.5

바이오가스는 Biomass, 유기성 폐기물 등의 혐기소화 공정을 통해 얻을 수 있는 대표적인 신재생연료로 저발 열량에도 불구하고 탄소중립적인 특성이 있기 때문에 이를 엔진에 적용하여 에너지를 생산하고자 하는 노력이 계속되어왔다. 바이오가스는 원료의 종류 및 혐기소화 공정 조건에 따라 그 연료 조성이 달라질 수 있는데, 이러한 조성 변화는 엔진 성능에 큰 영향을 미칠 수 있기 때문에 이에 대한 연구가 필요한 실정이다. 따라서 이번 연구에서는 다양한 발열량을 갖는 바이오가스를 연료 내 불활성가스 비율을 변화시켜 모사하고 이를 이용하여 바이오가스 내 불활성가스 비율의 변화, 즉 발열량의 변화가 엔진 성능 및 배기 특성에 주는 영향을 파악하였다. 실험결과로 각 불활성가스 함량에 따른 최적 점화시기를 결정하였으며, 발열량 변화가 엔진 출력, 효율, 배기 성능에 미치는 영향을 제시하였다. Biogas obtained from the biodegradable organic wastes in an anaerobic digester consists of CH<SUB>4</SUB> and inert gases such as CO<SUB>2</SUB> and N<SUB>2</SUB>. Since the composition of biogas varies by anaerobic digester conditions and the origin of wastes, it is necessary to respond to these variations so as to make stable combustion and accomplish high efficiency when it is used as a fuel for power generating SI engines. In this study, efforts have been made to investigate the effect of changes in the calorific values of biogas on the engine performance and exhaust characteristics. The biogas was simulated by supplying of CH<SUB>4</SUB> with N<SUB>2</SUB> dilution of various ratios, and ECM was developed to achieve accurate control of ignition and combustion. The results show that as the CH<SUB>4</SUB> concentration of the biogas decreases, the optimal spark timing is advanced due to the elevated thermal capacity and lowered O<SUB>2</SUB> concentration of the in-cylinder charge. Furthermore, since combustion temperature was reduced by increased inert gas, NO<SUB>x</SUB> emissions decreased, whereas THC emissions increased.

바이오가스 내의 불활성 가스 성분 변화에 따른 SI 엔진의 연소특성 비교

박승현(Seunghyun Park),박철웅(Cheolwoong Park),이선엽(Sunyoup Lee),김창기(Changgi Kim) 한국자동차공학회 2011 한국자동차공학회 부문종합 학술대회 Vol.2011 No.5

Biogas can be obtained from biogenic materials through an anaerobic digestion process. Since biogas has lower calorific value than conventional gas fuels because of its inert gas components, and the composition of biogas varies depending upon the origin of the anaerobic digestion process, appropriate combustion strategies need to be established to maintain stable combustion when it applies to engine applications. In this study, efforts have been made to investigate characteristics of engine performance and emissions depending on variation of inert gas composition in biogas. Experiment has been carried out with a simulated biogas to the SI engine. The fractions of CO₂ and N₂ in the simulated biogas were changed from 0 to 60% by volume respectively. Experimental results show that the MBT spark timing was advanced as the fraction of inert gases in the biogas increased. In addition, increasing inert gas compositions in the biogas can reduce the NO<SUB>x</SUB> emissions. Moreover, NO<SUB>x</SUB> emission drop in CO₂ case was more significant than that of N₂ because of higher heat capacity of CO₂, while THC emissions showed opposite tendency. Thermal efficiency was slightly increased in N₂ case with elevation of N₂ content in biogas due to the decreased heat loss and PMEP. However, there is no difference in CO₂ case because deteriorated flame propagation speed countervails the above mentioned thermal efficiency increasing factors.

수소 첨가 바이오가스 연료를 사용하는 SI엔진에 EGR과 희박연소 전략 적용에 관한 실험적 연구

박승현(Seunghyun Park),박철웅(Cheolwoong Park),이선엽(Sunyoup Lee),김창기(Changgi Kim) 한국가스학회 2011 한국가스학회 학술대회논문집 Vol.2011 No.11

Protein Intake and the Nutritional Status in Patients with Pre-dialysis Chronic Renal Failure on Unrestircted Diet

( Jung Sik Park ),( Hae Hyuk Jung ),( Won Seok Yang ),( Hyeong Ho Kim ),( Soon Bae Kim ),( Su Kil Park ),( Changgi D. Hong ) 대한내과학회 1997 The Korean Journal of Internal Medicine Vol.12 No.2

발전용 합성가스 엔진의 수소 혼합 비율에 따른 연소 특성 연구

박승현(Seung Hyun Park),박철웅(Cheolwoong Park),이선엽(Sunyoup Lee),김창기(Changgi Kim) 대한기계학회 2011 大韓機械學會論文集B Vol.35 No.7

바이오매스나 기타 유기성 폐기물로부터 가스화공정을 거쳐 얻을 수 있는 합성가스는 환경보호와 화석연료고갈 방지 측면에서 유망한 대체연료 중 하나로 여겨지고 있다. 그러나 가스화로부터 얻어지는 합성가스는 일반적인 천연가스와 같은 가스연료에 비해 발열량이 낮고 연료조성이 불균일하여 내연기관에 적용시 안정적이고 지속적인 운전이 어렵다는 단점이 있다. 따라서 본 연구에서는 이러한 저발열량과 불균일한 가스 조성의 특징을 가진 합성가스가 연소에 미치는 영향을 파악하여 고효율의 엔진을 개발하고자 연구를 수행하였다. 저발열량의 합성가스를 모사하기 위하여 천연가스에 질소를 희석한 연료를 사용하였다. 또한 체적당 발열량을 유지하면서 동일유량조건으로 합성가스에 수소 혼합비율을 10~30%로 변화시키면서 연소 특성 변화를 살펴보았다. Internal combustion engines running on syngas, which can be obtained from biomass or organic wastes, are expected to be one of the suitable alternatives for power generation, because they are environment-friendly and do not contribute to the depletion of fossil fuels. However, syngas has variable compositions and a lower heating value than pure natural gas, owing to which the combustion conditions need to be adjusted in order to achieve stable combustion. In this study, a gas that has the same characteristics as syngas, such as low heating value (LHV), was produced by mixing N₂ with compressed natural gas (CNG). In addition, this study investigates the combustion characteristics of syngas when it is mixed with hydrogen in a ratio ranging from 10% to 30% with a constant LHV of total gas.

성인 요로 감염 환자에서 99mTc - DMSA 삼중검출기 SPECT 영상의 유용성

박정식(Jung Sik Park),문대혁(Dae Hyuk Moon),김순배(Soon Bae Kim),이명혜(Myung Hae Lee),류진숙(Jin Sook Ryu),배원규(Won Gyu Bae),박수길(Su Kil Park),홍창기(Changgi D . Hong),조경식(Kyung Sik Cho) 대한핵의학회 1992 핵의학 분자영상 Vol.26 No.2

N/A Although early diagnosis of urinary tract infection is important, the radiologic evaluation is still controversial because of the low sensitivity and the lack of cost-effectiveness. This study was carried out to evaluate the clinical utility of high resolution triple head Tc-99m-DMSA SPECT imaging in urinary tract infection. We prospectively performed Tc-99m-DMSA planar and SPECT imaging, ultrasound of kidney (US), intravenous pyelography (IVP) and voiding cystourethrography (VCU) in all 60 adult patients with UTI [26 with first episode of acute pyelonephritis (APN), 22 with recurrent APN, and 12 persistent asymptomatic pyuria] and 25 normal persons. To assess reversibility of the renal cortical defect (RCD), Tc-99m-DMSA SPECT was repeated 1 to 8 months later in those patients with abnormal initial findings. Overall detection rate of Tc-99m-DMSA SPECT imaging was 83% (50/60), but planar, US, IVP and VCU showed abnormal findings in 68%, 28%, 32% and 13%, respectively. 25 out of 27 patients with nonnal or single RCD were all normal in other radioligic studies. Only two patients showed vesicoureteral reflux (VUR) on VCU (grade I) and mild hydronephrosis on IVP. But, high proportion of those with multiple RCD showed abnormal findings on US (17/33), IVP (18/33), and VCU (7/33): 67% in any of these 3 studies. Especially, 3 out 7 patients with VUR showed multiple RCD on Tc-99m- DMSA SPECT without any abnormality on IVP or US. 25 normal persons showed normal findings in all studies except one false positive finding on Tc-99m-DMSA SPECT imaging. Follow-up Tc-99m-DMSA SPECT was done in 28 patients (13 with single RCD, 15 with multiple RCD). All 13 patients with single RCD showed improvement. Those with multiple RCD presented improvement in 4, no change in 10, and aggravation in 1 on follow-up studies. With these results, we conclude: 1) Tc-99m-DMSA SPECT imaging is superior to planar imaging, US, IVP or VCU in detection of renal lesion in urinary tract infection. Tc-99m-DMSA SPECT is useful as a initial diagnostic tool in adult patients with urinary tract infection. 2) The multiple RCD on Tc-99m- DMSA SPECT represent the high probability of irreversible tissue change and need of extensive urological work-up.

A comparative study of lean burn and exhaust gas recirculation in an HCNG-fueled heavy-duty engine

Park, Cheolwoong,Lee, Sunyoup,Kim, Changgi,Choi, Young Elsevier 2017 International journal of hydrogen energy Vol.42 No.41

<P><B>Abstract</B></P> <P>Two dilution strategies, exhaust gas recirculation (EGR) with a stoichiometric mixture and excess air with a lean mixture, were investigated for an 11 L, 6-cylinder H<SUB>2</SUB>-blended compressed natural gas (HCNG) engine. The engine was operated at 1260 rpm and 50% of maximum engine load (575 Nm) at maximum brake torque for each strategy. To evaluate the EGR approach, the stoichiometric combustion mode was varied, and to evaluate the lean combustion mode, the excess air ratio was varied. The maximum EGR rate and lean flammability limit were constrained by the combustion stability. The dilution rate was employed to compare the dilution effect on engine performance and emission levels under identical levels of the dilution for both combustion modes. The thermal efficiencies under stoichiometric combustion with EGR were lower than those under lean combustion, owing to a higher pumping loss and a lower combustion speed. The total hydrocarbon emissions under the lean combustion mode were lower than those under the stoichiometric combustion mode only when the combustion speed was relatively slow, due to the higher mixing rate caused by the active combustion. As the dilution rate was increased in the lean combustion mode, the rate of decrease in NO<SUB>x</SUB> emissions slowed compared to the stoichiometric combustion mode. The lowest level of engine-out NO<SUB>x</SUB> emissions was observed under lean combustion.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The maximum dilution rates of an HCNG engine are 27.3% for EGR and 48.6% for lean-burn. </LI> <LI> The efficiency with EGR is lower owing to pumping loss and combustion temperature. </LI> <LI> THC emissions with lean-burn are lower under a low combustion speed because of mixing rate. </LI> <LI> The lowest level of engine-out NOx is observed with lean-burn. </LI> </UL> </P>

The influence of hydrogen-enriched gas on the performance of lean NO<i>_x</i> trap catalyst for a light-duty diesel engine

Park, Cheolwoong,Kim, Changgi,Kim, Kwantae,Lee, Daehoon,Song, Younghoon,Moriyoshi, Yasuo Elsevier 2010 International journal of hydrogen energy Vol.35 No.4

<P><B>Abstract</B></P><P>Modern diesel engines have improved engine fuel economy and significantly reduced nitrogen oxides (NO<I><SUB>x</SUB></I>) and particulate matter (PM) emissions achieved by advances in both combustion and exhaust aftertreatment technologies. Recently, it has been shown that the vehicle emissions can be further improved by several catalytic systems including fuel reformers and aftertreatment systems, such as the Lean NO<I><SUB>x</SUB></I> Trap (LNT). This NO<I><SUB>x</SUB></I> removal system, called LNT, absorbs NO<I><SUB>x</SUB></I> under lean exhaust gas conditions and releases NO<I><SUB>x</SUB></I> under rich conditions. This technology can provide high NO<I><SUB>x</SUB></I> conversion efficiency, but the right amount of reducing agent should be supplied into the catalytic converter under appropriate conditions.</P><P>In this work, plasma reformer was used to supply a hydrogen-enriched gas as a NO<I><SUB>x</SUB></I> reductant. The plasma reforming is one of the most promising on-board reforming technologies, which allows reformates containing H<SUB>2</SUB> and CO to feed for LNT catalyst efficiently. Partial oxidation is induced by plasma in the fuel reformer and diesel fuel is converted into a hydrogen-enriched gas.</P><P>The supplying strategy was focused on the maximization of NO<I><SUB>x</SUB></I> reduction efficiency varying both the total amount of hydrogen-enriched reformate and the ratio of oxygen molecules to in the reformer air-fuel mixture prior to processing at a fixed engine operating condition. The effect of exhaust gas temperature was also studied. The NO<I><SUB>x</SUB></I> reduction efficiency is closely connected to the amount of supplied fuel to the plasma reformer and the ratio of fuel/air feed rate. The LNT can reduce NO<I><SUB>x</SUB></I> efficiently with only a 2.6% fuel penalty.</P>

EFFECTS OF PASSAGES ON THE EXTRACELLULAR MATRIX SYNTHESIS BY CULTURED RAT MESANGIAL CELLS

Park, Jung Sik,Kim, Soon Bae,Choe, Mi Kyeong,Hong, Changgi D 대한신장학회 1994 Kidney Research and Clinical Practice Vol.13 No.2