고정층과 순환유동층에서 CaSO_4의 환원반응에 대한 온도와 CO농도의 영향

배달희,류호정,박재현,이창근,선도원,이동규 한국화학공학회 2003 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.41 No.1

순환유동층 석탄연소로에서 석회석에 의한 찰황반응에 영향을 미치는 CaSO_4의 환원반응에 의한 SO-2 재배출을 실험적으로 확인하고 SO_2의 재배출에 미치는 온도와 CO 농도의 영향에대해 상용 순환유동층에 적용할 수 있는 기초자료를 확보하기 위해 고정층과 순환유동층에서 층물질로 석회석과 상용 순롼 유동층 하부회를 이용하여 환원실험을 수행하였으며 CaSO_4의 환원반응에 미치는 온도와 CO의 영향을 측정 및 해석하였다. 고온조건에서 CO가 환원제로 작용하여 C_aSO_4로부터 SO_2가 재배출되는 현상을 확인하였으며 CaSO_4로부터 SO_2의 재배출은 온도와 CO농도가 증가함에 따라 증가하였다. 본 실험의 결과에 의해 온도가 증가함에 따라 석회석에 의한 탈황율이 감소하는 현상을 환원이론으로 설명할 수 있다는 것이 확인되었다. For qualitative understanding of the sulphur capture process in a circulating fluidized bed fumace, the effects of temperature and CO concentration on the reactivity of partially sulfated CaO were experimentally examined. The tests were performed in a fixed bed reactor and lab-scale circulating fluidized bed reactor. The materials used were partially sulfated domestic limestone and bottom ash drained from commercial circulating fluidized bed furnaces. The re-emission of SO_2 from partially sulfated limestone and bottom ash increases with temperature as well as with concentration of the reducing agent CO. From the results of this study, the temperature dependence of sulfation could be explained by reduction theory.

경연대회를 통한 초·중고생의 창의력 현황에 관한 연구

육근철,이희복,류해일,김현섭,김희수,박달원,심규철,박종석,신영숙,박상태,변두원,김태균 공주대학교 과학교육연구소 2002 과학교육연구 Vol.33 No.-

21세기의 정보화 산업사회와 지식기반 사회에서 우리의 아이들이 자신의 목소리로 세계 속에서 살아가게 하기 위해서는 다른 사람과 다른 아이디어를 낼 수 있도록 교육의 틀을 바꾸지 않으면 안된다. 다라서 21세기의 미래 사회를 살아갈 학생들을 가르치는 교육의 현장 역시 창의적인 인간을 길러낼 수 있도록 변해야 한다. 즉, 미래 사회를 대비하기 위해서는 각 개인의 개성을 존중하는 분위기에서 창의적인 능력을 지닌 인간을 양성해야 한다는 것을 의미한다. 따라서, 학교 안에서의 교육뿐만이 아니라 학교 밖에서도 다양한 학습 경험을 통해서 교육 과정이 추구하는 인간상을 구현할 수 있도록 활동할 수 있는 기회가 학생들에게 제공되어야 한다. 창의력을 발휘하여 문제를 해결하는 능력을 기르기 위해서는 개별적이 아닌 여러 명의 동료가 주어진 과제를 해결할 수 있는 기회를 갖고 짧은 시간이 아닌 장시간 동안 고민하고 그 해결책을 찾는 활동을 가질 기회가 필요하다. In order to educate our students with their special talents for the informational and knowledge based age expected in the 21st century, we must improve our educational programs such that students are able to create their own fresh ideas. Hence the present educational environment should be changed such that they are willing to respect others' characters and personality with their own original ideas. Therefore, we must make them have the opportunity that they can acquire many experiences through the school education and the social education program, so that they may grow up to the person with the humanity and creativity. In this study we have suggested new educational program where students engage themselves in long term research projects with collaboration of the team and creativity of individuals.

전방 또는 전측방 흉수 종양 수술에서 후측방도달법

조경석,박춘근,성재훈,허필우,박춘근,백민우,김달수,강준기 대한신경외과학회 1997 Journal of Korean neurosurgical society Vol.26 No.5

경연 대회를 통한 초ㆍ중고생의 창의력 신장 효과에 관한 연구

이희복,육근철,류해일,김현섭,김희수,박달원,유병환,김선효,김여상,서광수,변두원,서명석,배성효,박종석,심규철,이성희 공주대학교 과학교육연구소 2001 과학교육연구 Vol.32 No.1

미래 사회를 대비하기 위한 개인의 개성을 존중과 창의적인 능력을 지닌 인간을 양성을 목적으로 충청남도 지역의 초 ㆍ 중고등학생들을 대상으로 한 창의력 경연대회가 공주대학교 과학교육연구소에서 개최되었다. 충청남도 초 ㆍ중 ㆍ 고등학생들을 대상으로 실시한 창의력 경연대회는 창조적 아이디어를 내어 스스로 문제를 해결해 나갈 수 있는 교육 프로그램을 제공하는 좋은 기회였음이 확인되었으나, 일부의 팀에서만 참신하고 재미있는 아이디어들이 제안되었다. 여학생의 참가자 수가 상당히 증가하였으며, 대체적으로 입상권의 학생들의 상당 부분이 여학생이라는 것이 특이할만하다. 학년이 올라감에 따라서 창의적인 아이디어를 내는 양이나 질에 있어서 뒤떨어지는 것으로 분석되었으며, 토론 학습의 적응력이 미흡하고 발표력 및 청취력에 있어서도 떨어지는 것으로 나타났다. 따라서 중 ㆍ고등학교의 학교교육에서도 학생들에게 프로젝트형 탐구학습 프로그램의 적용은 물론 토론식 수습을 통한 학생들의 사고의 전환의 기회를 제공해야 할 것으로 사료된다. The creativity competition was held to foster the creativity of elementary and secondary school students in the Institute of Science Education, Kongju national University. It was found that the creativity competition effected on the improvement of inventing creative ideas and problem solving activities. But, only some competitors participated in semifinal and final contests, presented original and interesting ideas. More female students participated in competition than last year. More female participants were awarded a prize than males. Totally, participants were defective in discussion and communication, and presentation and listening ideas. Increasing grades correlated inversely with creativity and originality. There is need of inquiry project teaming programs and presenting opportunities of conversion of thinking by discussing instructions in school

Fluidized Bed Combustion of High Ash Anthracite : Analysis of Combustion Efficiency and Particle Size Distribution

Park, Dal Keun,Jung, Yong Won 한국화학공학회 1988 NICE Vol.6 No.4

Fluidized bed combustion of high ash anthracite (HAA) was experimentally studied. The combustor consists of 0.25m ID bed, and auxiliary equipments for coal feeding, ash removal, temperature control, etc. Experimental results elucidate main cause of fuel loss to be elutriation of fines(i.e., flyash) containing unburned carbon. However, detailed balances of particle size distribution show majority of carbon in flyash comes from fines contained in the feed instead of attrition of coarse particles. The latter is the main source of flyash for conventional coal. The difference is due to much smaller attrition rate of HAA feed HAA panicles do not shrink much in size by combustion and attrition.

HYDROGEN PRODUCTION FROM FLUIDIZED BED STEAM REFORMING OF HYDROCARBONS

Park, Dal Keun,Lee, Joong Kee 한국화학공학회 1998 Korean Journal of Chemical Engineering Vol.15 No.6

Steam reforming of methane, kerosene and heavy oil over a nickel/alumina commercial catalyst and other materials such as limestone, dolomite and iron ore, was studied using a 5 cm i.d. fluidized bed reactor. The effects of operating parameters on conversion, hydrogen yield, product gas composition and elutriation of fine catalysts were investigated. It was found that a fluidized bed is flexible enough to handle various feedstocks, including hydrocarbons heavier than naphtha, because it permits the addition of catalyst to, or withdrawals of, coked catalyst from the bed. The yield of hydrogen obtained from fluidized bed steam reforming of heavy oil at 800℃ over limestone was similar to that obtained over commercial nickel-based catalyst. This indicates that limestone could be a promising catalyst for the production of hydrogen from heavy oil. However, hydrogen yield decreased with reaction time in the experiments using the limestone catalyst. The main cause of the decrease in hydrogen yield was elutriation of fine catalysts from the bed during the reaction.

FLUIDIZED BED COMBUSTION OF HIGH ASH ANTHRACITE : ANALYSIS OF COMBUSTION EFFICIENCY AND PARTICLE SIZE DISTRIBUTION

Park, Dal Keun,Jung, Yong Won 한국화학공학회 1988 Korean Journal of Chemical Engineering Vol.5 No.2

Kinetics of Steam Reforming over a Ni/Alumina Catalyst

Park, Dal Keun,Shin, See Hee,Lee, Joong Kee,Ko, Ki Dong 한국화학공학회 1995 NICE Vol.13 No.6

Steam reforming of methane over a commercially available, nickel/alumina catalyst was experimentally studied. the reactor employed for the study was made of 7mm i.d. quarta tube and catalyst particles were 0.84∼1 mm in size. The amount of catalyst charge in the reactor was, mound 0.3 gram. Experiments were carried out varying the steam to methane ratio in the from gas from 1 to 10 and reaction temperature from 823 to 1073 K. Nitrogen gas was used to control partial pressure of methane and steam. Using Mnrquardt method reaction ratty derived from the experiments was fitted to (수식) Thus reacts order was close to one Ior methane and close to minus one fur steam, respectively.

Surface Modification of Polyurethane Using Sulfonated PEG Grafted Polyrotaxane for Improved Biocompatibility

Park Hyung Dal,Bae Jin Woo,Park Ki Dong,Ooya Tooru,Yui Nobuhiko,Jang Jun-Hyeog,Han Dong Keun,Shin Jung-Woog The Polymer Society of Korea 2006 Macromolecular Research Vol.14 No.1

Sulfonated poly(ethylene glycol) (PEG-$SO_{3}$) grafted polyrotaxanes (PRx-PEG-$SO_{3}$) were prepared in order to utilize the unique properties of PEG-$SO_{3}$ and the supramolecular structure of PRx, in which PEG-$SO_{3}$ grafted $\alpha$-cyclodextrins ($\alpha$-CDs) were threaded onto PEG segments in a PEG-b-poly(propylene glycol) (PPG)-b-PEG triblock copolymer (Pluronic) chain capped with bulky end groups. Some of the PRx-PEG-$SO_{3}$ demonstrated a higher anticoagulant activity in case of PRx-PEG-$SO_{3}$ (P 105), and compared with the control they showed a lower fibrinogen adsorption in PRx-PEG-$SO_{3}$ (F68) and a higher binding affinity with fibroblast growth factor. The obtained results suggested that polyrotaxane incorporated with PEG-$SO_{3}$ may be applicable to the surface modification of clinically used polymers, especially for blood/cell compatible medical devices.

Effect of Hypothermia on the Expression of c-fos and c-jun Protooncogenes in a Transient Global Cerebral Ischemic Model of Gerbil

Kim, Dal-Soo,Park, Young-Sup,Chol, Chang-Rak,Park, Hae-Kwan,Park, Sung-Chan,Cho, Kyung-Keun,Kang, Joon-Ki CATHOLIC MEDICAL CENTER 1996 Bulletin of the Clinical Research Institute Vol.21 No.1

Increased release of excitatory neurotransmitters leading to activation of signal transduction has been noted after cerebral ischemia. One of the biochemical events in the signaling processes is an alteration of gene expression, that is, increased expression of immediate early genes(IEGs) such as the protooncogenes, c-fos and c-jun. Recent studies have shown that hypothermia has a beneficial protective effect on hippocampal neuronal loss during or after cerebral ischemia. In this study, we investigated the expressions of c-fos and c-jun by immunohistochemical stain at the hippocampal CA1, CA3 and parietal cortex(PC) along the changes of body temperature in a transient global cerebral ischemia model of gerbil in order to check the effect of hypothermia. The experimental groups were divided into control(36-36.5℃), normothermic(36-36.5℃), hypothermic(32-33℃) and hyperthermic groups(38-39℃) and a transient global cerebral ischemia was made by clipping of both common carotid arteries for 10 minutes, followed by reperfusion for 120 minutes. The results were as follows; 1. In all ischemic groups, the expressions of c-fos and c-jun were increased compared with the control group. The expression of c-fos was markedly enhanced and that of c-jun was also enhanced in a similar pattern, but lower in count than that of c-fos. 2. The expression of c-fos at the hippocampal CA1 was enhanced significantly in all three ischemic groups compared with the control group (P<0.01). At the hippocampal CA3 and parietal cortex(PC), the expression was enhanced significantly in the normothermic and hypothermic groups (P<0.01), but not in the hyperthermic group compared with the control group. 3. The expression of c-jun at the hippocampal CA3 was enhanced significantly in the hypothermic group compared with all other groups (P<0.01) but there was no significant change in hippocampal CA1 and PC. 4. In the aspect of location in each experimental group, the expressions of both protooncogenes were increased in CAKCA3<PC in that order in all ischemic groups except the control group (P<0.01). In conclusion, the expressions of protooncogenes would be increased as a stress response for cell survival from ischemic insult during the early post-ischemic stages and c-fos, not c-jun, may play a major role in upregulating other genes in response to exogenous stimuli. These results also suggest that the parietal cortex is more resistant to ischemic injury than the hippocampus and hypothermia may have a beneficial neuroprotective effect by enhancing the expression of these protooncogenes in the early stage of cerebral ischemia.