Brain SPECT 영상의 Attenuation Correction 방법들에 대한 비교

조진우,김창호,나수경,이귀원,Jo, Jin U,Kim, Chang Ho,Na, Soo Kyung,Lee, Gui Won 대한핵의학기술학회 2012 핵의학 기술 Vol.16 No.2

이 연구의 목적은 Brain SPECT (Single Photon Emission Computed Tomography)의 Non-attenuation correction (AC-non) 영상에 대한 attenuation correction(AC) 방법 중 Chang's method와 CT based attenuation correction(AC-CT) 사이의 count를 비교하기 위함이다. phantom study는 증류수로 채워진 hoffman 3D phantom에 $^{99m}Tc$ 37Mbq을 투여하였고, patient study는 normal volunteer에 $^{99m}Tc$-HMPAO 750Mbq를 정맥주입하고 Siemens사의 Symbia T6로 Brain SPECT 영상을 획득하였고 뇌 정량 분석을 하였다. 각각의 방법들을 적용한 transverse image는 같은 위치에서 재구성 되었으며 각각 10, 20, 30번째 slice에서 6개의 region of interest(ROI)를 그려 AC-non 과 AC-CT 그리고 Chang's method의 count를 비교하였다. phantom study에서 AC-non, AC-CT, Chang's method의 각각 평균 count는 $4606.8{\pm}511.3$, $16794.6{\pm}2429.4$, $8752.6{\pm}896.5$이었으며 patient study에서 $5460.8{\pm}519.6$, $15320{\pm}1171.6$, $12795{\pm}1422.1$이었다. phantom study에서 AC-CT와 AC-non 사이의 비는 3.70이고 Chang's method와 AC-non 사이의 비는 1.92였으며 patient study에서는 각각 2.85, 2.38이었다. 우리는 이 연구를 통하여 AC-CT가 Chang's method보다 더 높은 AC을 해준다는 걸 알 수 있었다. 그리고 Chang's method는 patient study에서의 AC 값이 phantom study에서의 AC값보다 더 높다는 것을 알 수 있었다. brain SPECT/CT를 시행하는 경우 scatter correction을 같이 시행하고 bone에 의한 감쇠 정보를 반영할 수 있는 AC-CT가 chang's method보다 정확하다 할 수 있겠다. Purpose : The purpose of this study was to compare count between Chang's method and CT-based attenuation correction (AC-CT) among the attenuation correction (AC) methods for non-attenuation correction (AC-non) images of Brain SPECT (Single Photon Emission Computed Tomography). Materials and Methods : We injected $^{99m}Tc$ 37Mbq in a Hoffman 3D phantom filled with distilled water in the phantom study, and injected intravenously $^{99m}Tc$-HMPAO 740Mbq in a normal volunteer in the patient study, and then obtained Brain SPECT images with Symbia T6 of Siemens and conducted quantitative brain analysis. Transverse images to which each method was applied were rebuilt at the same position, and 6 regions of interest (ROI) were drawn on each of Slice No. 10, 20 and 30 and then the counts of AC-non, AC-CT and Chang's method were compared. Results : The mean counts of AC-non, AC-CT and Chang's method were $4606.8{\pm}511.3$, $16794.6{\pm}2429.4$, and $8752.6{\pm}896.5$, respectively, in the phantom study and $5460.8{\pm}519.6$, $15320{\pm}1171.6$ and $12795{\pm}1422.1$, respectively, in the patient study. In the phantom study, the ratio of AC-CT to AC-non was 3.70 and the ratio of Chang's method to AC-non was 1.92, and in the patient study, they were 2.85 and 2.38, respectively. Conclusion : From this study, we found that AC-CT makes higher AC than Chang's method. In addition, when Chang's method was used, AC in the patient study was higher than that in the phantom study. These results need to be considered also in other examinations.

액체로켓엔진의 성능 민감도 해석

조원국(Won Kook Cho),남창호(Chang Ho Nam),박순영(Soon Young Park),김철웅(Chul Woong Kim) 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.11

A sensitivity analysis of the liquid rocket engine has been made. A mode analysis program is used to predict the performance change due to the variation of rocket engine operating environment. The propellant supply pressure and density are the major variables of the operating condition. The material properties of the turbine driving gas is assumed as the function of mixture ratio. The discrepancies of performance change between constant turbine driving gas properties and variable properties are greater for the case of fuel pump inlet pressure change than the oxidizer pump inlet pressure change.

Anti-Inflammatory and Analgesic Effects of Pyeongwisan on LPS-Stimulated Murine Macrophages and Mouse Models of Acetic Acid-Induced Writhing Response and Xylene-Induced Ear Edema

Oh, You-Chang,Jeong, Yun Hee,Cho, Won-Kyung,Ha, Jeong-Ho,Gu, Min Jung,Ma, Jin Yeul MDPI 2015 INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES Vol.16 No.1

<P>Pyeongwisan (PW) is an herbal medication used in traditional East Asian medicine to treat anorexia, abdominal distension, borborygmus and diarrhea caused by gastric catarrh, atony and dilatation. However, its effects on inflammation-related diseases are unknown. In this study, we investigated the biological effects of PW on lipopolysaccharide (LPS)-mediated inflammation in macrophages and on local inflammation <I>in vivo</I>. We investigated the biological effects of PW on the production of inflammatory mediators, pro-inflammatory cytokines and related products as well as the activation of nuclear factor kappa B (NF-κB) and mitogen-activated protein kinases (MAPKs) in LPS-stimulated macrophages. Additionally, we evaluated the analgesic effect on the acetic acid-induced writhing response and the inhibitory activity on xylene-induced ear edema in mice. PW showed anti-inflammatory effects by inhibiting the production of nitric oxide (NO), tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) and interleukin-1β (IL-1β). In addition, PW strongly suppressed inducible nitric oxide synthase (iNOS), a NO synthesis enzyme, induced heme oxygenase-1 (HO-1) expression and inhibited NF-κB activation and MAPK phosphorylation. Also, PW suppressed TNF-α, IL-6 and IL-1β cytokine production in LPS-stimulated peritoneal macrophage cells. Furthermore, PW showed an analgesic effect on the writhing response and an inhibitory effect on mice ear edema. We demonstrated the anti-inflammatory effects and inhibitory mechanism in macrophages as well as inhibitory activity of PW <I>in vivo</I> for the first time. Our results suggest the potential value of PW as an inflammatory therapeutic agent developed from a natural substance.</P>

XP-SWMM 모형을 이용한 침수지역의 수치모의

이호진(Ho Jin Lee)(李昊振),장창덕(Chang Deok Jang)(張昌德),전계원(Kye Won Jun)(全桂元) 위기관리 이론과 실천 2011 Crisisonomy Vol.7 No.2

최근 세계 곳곳에서 기후변화에 따른 자연재해의 발생확률이 점점 높아지고 있다. 우리나라도 예외가 될 수 없으며 특히 강원도 지역의 경우 태풍과 홍수의 피해가 가장 빈번히 발생하는 지역 중의 하나이다. 지난 2002년 태풍 루사와 2003년 태풍 매미로 많은 인명과 재산피해가 발생하였으며 이로 인해 재해위험지구 또한 증가 하였다. 따라서 본 연구에서는 침수해석을 위해 XP-SWMM을 적용하여 강원도 삼척시 자원동 지역을 대상으로 강우 자료와 지형자료를 분석하고 하천범람과 내수침수 범위를 수치모의 하였다. 모의결과 삼척시에서 제작한 침수흔적도와 비교하여 모의된 침수범위가 조사된 침수범위 보다 넓게 분포하는 경향을 나타내었다. 이는 모형에 사용된 지형자료의 정밀도에 기인한 결과로 분석되었다. 추후 연구에서는 주요지점에 대해 보다 해상도 높은 지형자료를 이용한 침수범위를 산정이 수행되어야 한다고 판단된다. Recently the possibility of the natural disaster has been increased around the world due to the climate change. Especially, Gangwon-do is one of the areas that the damage by storm and flood is most frequent. In 2002 and 2003, the typhoon Rusa and Maemi had generated huge losses of both life and property, resulted in increased number of natural hazard area. In this study, we analyzed the rainfall and geographical data of the Jawon-dong area, Samcheok City of Gangwon-do during the hit of typhoon Rusa, and XP-SWMM(Numerical Model) was applied to calculate the natural hazard area’s river flooding and inundation range.

Ischemia-Related Changes in Galanin Expression in the Dentate Hilar Region after Transient Forebrain Ischemia in Gerbils

LEE, Hyeon Yong,HWANG, In Koo,KIM, Dae Ho,KIM, Jung Hwa,KIM, Chang Ho,LIM, Beong Ou,KANG, Tae-Cheon,BANG, Kyung Hwan,SEONG, Nak Sul,LEE, Hak Ju,KIM, Jong Dai,WON, Moo Ho Japanese Association for Laboratory Animal Science 2005 EXPERIMENTAL ANIMALS Vol.54 No.1

<P>Although galanin (GAL) protects hippocampal neurons from ischemic damage, no study has examined ischemia-related changes in endogenous GAL in the hippocampal dentate gyrus. We investigated the chronological changes of GAL, well-known as the potassium channel opener, expression in the dentate gyrus at various times after 5 min of transient forebrain ischemia in gerbils. A few GAL-immunoreactive (IR) neurons were found in the polymorphic layer of the sham-operated group. Three hours after ischemia-reperfusion, the pattern of GAL immunoreactivity was similar to that of the sham-operated group and the number of GAL-IR neurons and immunoreactivity were highest 12 h after ischemic insult. At this time, GAL-IR neurons in the polymorphic layer showed strong GAL immunoreactivity. Thereafter, GAL-IR neurons and immunoreactivity significantly decreased in the dentate hilar region. Four days after ischemic insult, GAL-IR neurons were not detectable. In addition, the results of a Western blot study showed a pattern of GAL expression similar to the immunohistochemical changes. GAL protein content also was highest 12 h after ischemia. In conclusion, the increased expression of endogenous GAL in the dentate gyrus after ischemia is related to response to the ischemic damage.</P>

Carburization of Iron Using CO-H₂ Gas Mixture

Hwang, Ho-Sun,Chung, Uoo-Chang,Chung, Won-Sub,Cho, Young-Rae,Jung, Byong-Ho,Martin G.P. 대한금속재료학회 2004 METALS AND MATERIALS International Vol.10 No.1

Iron carbides formed on the surface of iron and iron oxide samples at 640℃ in a gas mixture of CO-H₂ were characterized by scanning electron microscopy (SEM), MGssbauer spectroscopy, X-ray diffraction patterns (XRD), and by measuring mass change. The Fe₃C amount of the samples has been quantitatively evaluated by the weight change during carburization. While Fe₂O₃ powder was mostly completed to Fe₃C in the early stage, within 5 min after reduction reactions, the conversion of Fe powder sample to Fe₃C (iron carbide) was almost finished after 10 min. The carburization rate of a Fe sheet was very slow and intermediate products (Fe₂C, Fe₃C₂) were observed. This phenomenon is largely due to the difficulty of carbon diffusion into its dense surface. It was found that the carburization rate was affected by change of surface conditions and surface area by reduction, degradation, and cracks at high temperature. This study should help provide a fundamental understanding of carburization in the field of iron-making and suggest a direction for its further development.

위용종의 내시경적 생검과 내시경적 절제술 후 병리학적 진단의 불일치

윤원재 ( Won Jae Yoon ),이동호 ( Dong Ho Lee ),이국래 ( Kook Lae Lee ),장동경 ( Dong Kyung Chang ),김병관 ( Byeong Gwan Kim ),김지원 ( Ji Won Kim ),정지봉 ( Ji Bong Jeong ),김나영 ( Na Young Kim ),김진욱 ( Jin Wook Kim ),황진혁 ( 대한내과학회 2005 대한내과학회지 Vol.69 No.5

목적 : 위용종이란 위의 내강으로 돌출한 종괴를 의미한다. 거의 90%에서 조직학적으로 과형성 용종이며 이러한 경우 암으로의 진행은 매우 적은 것으로 알려져 있다. 그러나 위선종은 일부에서 국소적으로 암성 병변을 동반하거나, 동반하고 있지 않더라도 시간이 지남에 따라 암으로 진행하는 것으로 알려져 있다. 그러나 내시경적 겸자 생검과 전체 병변의 절제 후 조직 소견에서는 차이가 있는 것으로 알려져 있다. 저자들은 내시경검사에서 위용종이 발견된 후 내시경적 절제술을 시행받은 74명의 환자, 85예의 위용종을 대상으로 임상적 및 병리학적 특성을 알아보고 겸자 생검과 내시경적 절제술 후 병리학적 진단의 불일치를 알아보고자 하였다. 방법 : 1996년 4월부터 2003년 2월까지 내시경검사에서 위용종이 발견된 후 내시경적 생검과 내시경적 절제술 후 조직학적 진단이 모두 이루어진 74명의 환자를 대상으로 내시경 사진, 의무 기록 및 병리 기록을 분석하였다. 결과 : 74명의 환자에서 총 85개의 용종을 관찰할 수 있었다. 위용종은 전정부에서 가장 호발하였으며(58.8%) 그 다음으로는 체하부(18.8%)에 호발하였다. 내시경적 겸자 생검에서 관상 선종은 48.2%, 과형성 용종은 30.6%, 염증성 용종은 15.3%, 위저선 용종은 2.4%, 이형성증은 2.4%, 관상융모 선종은 1.1%였다. 내시경적 절제술 후 조직학적 검사상 관상 선종은 45.9%, 과형성 용종은 31.8%, 염증성 용종은 9.4%, 과오종은 3.5%, 위저선 용종은 2.4%, 관상융모 선종은 2.4%, 선암은 2.4%, 이형성증은 1.1%, 점막 위지방종증은 1.1%였다. 내시경적 겸자 생검 결과와 내시경적 절제술 후 조직학적 진단의 불일치율은 27.1%였다. 용종의 크기에 따른 진단 일치율의 차이는 없었다(p>0.05). 결론 : 위용종의 겸자 생검과 내시경적 절제술 후 조직검사 소견은 차이가 있을 수 있다. 용종의 크기는 진단 일치율에 영향을 미치지 못했다. 따라서 특히 선종이 의심되는 경우에는 크기에 상관없이 내시경적 절제술을 통한 전체 병변의 조직검사가 필요할 것으로 생각된다. Background : Gastric polyp is a descriptive term referring to mucosal prominence that protrudes beyond the flat lining of the stomach. Almost 90% of gastric polyps are hyperplastic polyps. Adenomatous polyps may contain focal carcinomatous foci or undergo carcinomatous changes. It is known that there is some degree of discordance between the results of endoscopic forceps biopsy and pathology of resected specimens. The aim of this study was to investigate the discordance in pathologic findings between endoscopic forceps biopsy and endoscopic resection specimen of gastric polyps. Methods : We reviewed endoscopic photographs and medical records of the patients who underwent endoscopic resection from April, 1996 through February, 2003. Results : A total of 85 cases of gastric polyps from 74 patients were reviewed. Male-to-female ratio was 1:1.96. Mean age was 59.9±10.8 years. Multiple polyps were observed in 10.8%. Gastric polyps occurred in the antrum most frequently (58.8%). Pathology results on resected specimens were as follows: tubular adenoma 45.9%, hyperplastic polyp 31.8%, inflammatory polyp 9.4%, hamartoma 3.5%, fundic gland polyp 2.4%, tubulovillous adenoma 2.4%, adenocarcinoma 2.4%, dysplasia 1.1%, and mucosal pseudolipomatosis 1.1%. Discordance rate between endoscopic biopsy and pathology of resected specimens was 27.1%. There was no relationship between the size of the polyp and concordance rate. Conclusions : There was considerable discordance in pathologic findings between endoscopic forceps biopsy and resected specimens. Approaches to review the histology of an entire polyp should be performed, especially when an adenoma is suspected.(Korean J Med 69:481-486, 2005)

정책홍보 수행과정 모델에 따른 정책홍보 수행 현황과 모델 충실도 연구

신호창(Shin Ho-Chang),이두원(Lee Du-Won),김정선(Kim Jung-Sun) 한국정치정보학회 2006 정치정보연구 Vol.9 No.2

국가정책에 대한 홍보는 국민의 의견을 수렴하여 정책을 결정하는 사전 홍보로부터 시작하여, 정책을 집행하기 전 문제관리 및 위기 예방차원의 홍보, 정책 집행을 효과적으로 수행하기 위한 홍보 프로그램 수행, 그리고 효과 평가에 이르기까지 단계적으로 수행되어야 한다. 국가의 정책홍보 프로세스는 크게 정책 구상 단계, 정책 결정 단계, 정책 발표 및 집행 단계, 정책 홍보 효과 평가 단계인 4가지 단계로 분류된다. 이를 기본으로 각 단계별 세부 내용에 따라 국가정책의 홍보 활동을 제시하고 분석할 수 있다. 본 연구에서는 이러한 정책홍보의 수행과정 모델에 따른 정책홍보 수행 현황과 모델 충실도를 파악해보고자 하였다. 따라서 과연 국가의 정책 수행 과정 속에서 실제 ‘정책홍보’는 어떻게 이루어 지고 있으며, 정책 홍보를 담당하는 부처 담당자들은 정책홍보의 수행 과정 절차를 충실하게 따라 이행하고 있는가에 연구의 초점을 맞추었다. 특히 정책홍보 담당자들이 단계별 정책홍보 수행 내용을 충실하게 이행하고 있는지, 만일 그렇지 않다면 어떤 이유가 주된 것인지, 그 문제를 파악하여 정책 홍보 담당자들에게 효율적인 업무 수행 방향을 제시하고자 하였다. 또한 정부의 정책홍보 수행 과정에서 홍보팀과 비홍보팀간의 수행정도의 차이가 있는가를 살펴보고자 하였다. Government policy PR activities range, longitudinally, from the conception step of a policy to the completion of the policy and include, latitudinally, such PR activities as media relations, community relations, issue and crisis management, MPR, advertising campaign, and public affairs. For the last several years Korean government has emphasized the Policy PR practices to acquire people's supports and agreements on her policies. However, regardless of Korean government's effort to promote the policy PR activities, many opinion leaders and the press have pointed out the lack of the government's rapport with people in policy PR communication. The purpose of this study is to examine "the fulfillment of the performative model for the government policy PR practices." In this study “the performative model for the government policy PR practices" indicates "the model for the proper policy PR practices at the four different stages of carrying out a policy, i.e., the stages of policy designing, decision-making, carrying out, and evaluation. Accordingly, four research questions are explored surveying 160 government officials and the results of each question are briefly as follows: Firstly, at the stage of 'a policy designing' how substantially the PR research and proactive PR activities are carried out and is there substantial difference between the policy PR team and other task teams in the fulfillment of those policy PR activities? The study result shows that some substantial PR activities like planning, proactive communication, building media relation, etc. are being carried out. Secondly, at the stage of decision-making on the policy, how substantially the PR activities needed at this stage are carried out and is there substantial difference between the policy PR team and other task teams in the fulfillment of those policy PR activities? The study result indicates that some substantial PR activities like public analysis, issue analysis, PR program planning, building cooperative relationships are being carried out; yet, the limitation of PR budgets, personal resources, sincerity in proactive policy PR still needs to be improved. Thirdly, at the stage of 'carrying out a policy,' how substantially the PR activities needed at this stage are carried out and is there substantial difference between the policy PR team and other task teams in the fulfillment of those policy PR activities? The study result shows that at this stage such PR activities as internal communication, crisis management, PR agency consulting, publicity are often being practiced. Fourthly, at the stage of a 'policy evaluation,' how substantially the policy PR activities are evaluated and is there substantial difference between the policy PR team and other task teams in the fulfillment of the policy PR evaluation? The study result shows that a policy PR evaluation is mostly being focused on publicity on media and the evaluation result is sometimes used as the feedback for the next project. However, there appeared the lack of evaluation on those target audiences' attitude changes. And, at the four stages of carrying out a policy, there appeared respectively some significant differences between the policy PR team and other task teams in the fulfillment of those policy PR activities required at each stage.

농촌지역 사회적기업의 성과 평가와 지원방안

오내원(Nae-Won Oh),김창호(Chang-Ho Kim),권인혜(In-Hey Kwon),오세익 한국농촌경제연구원 2010 한국농촌경제연구원 기본연구보고서 Vol.- No.-

최근 사회적기업에 대한 관심이 증대하는 가운데 기업으로서의 지속가능성에 우려가 제기되고 있다. 그러나 사회적기업의 지속가능성은 일반 기업과는 달리 평가되어야 한다. 사회적기업에 대한 경영 성과는 해당 기업들이 이룬 사회적 파급효과도 포함되어야 하기 때문이다. 설문조사 결과 농촌지역 사회적기업은 대체로 경영수지 균형을 이루고 있는 것으로 나타났다(90.3%가 흑자 또는 수지균형). 총수입액으로 본 농촌 사회적기업의 경영규모는 평균 4억 4,000만 원 정도로 작은 편이었다. 총 수입액 중 영업수익(매출액)의 비중으로 계산되는 재정자립도는 평균 70%대로 예상보다 높았고 외국과 비교해도 낮은 수준은 아닌 것으로 판단되었다. 그렇지만 30%를 차지하는 외부지원은 대부분 정부지원으로 충당되고 있으며 사회적 기부나 모기관의 지원 비중은 매우 낮았다. 정부지원에 대한 높은 의존도는 정책 변화에 따라 사회적기업의 지속가능성에 문제를 발생시킬 가능성이 큰 것으로 보인다. 농촌지역 사회적기업의 평균 고용규모는 22.5명이고 이 중 절반 정도가 취약계층인 것으로 나타나, 고용창출과 노동통합에도 상당히 기여하고 있다. 총수입 1억 원당 종사자 수가 5명으로 일반 기업에 비해 높은데, 이런 고용효과에도 불구하고 정부에서 지원하는 사회적일자리 창출사업의 지원기간이 1년마다 결정되는 등 사회적기업의 고용이 오히려 경영 불안정 요소로 작용하고 있기도 하다. 사회적기업의 경영 애로와 관련해서는 투자 확대의 어려움, 불리한 시장조건이 가장 큰 문제로 확인되었다. 대체로 사회적기업의 수익성이 취약해 자체 자금조달이 어렵고 외부적으로도 낮은 사업성 평가와 담보력 부족으로 금융기관에 대한 접근이 쉽지 않은 것으로 나타났다. 또 농촌 사회적기업은 자본과 기술의 부족, 저효율 노동력, 구매력이 부족한 고객, 농촌의 열악한 산업인프라 등 시장에서 경쟁력을 갖기에 불리한 조건이 많은 것으로 파악되었다. 이러한 점을 고려할 때 농촌지역 사회적기업에 대한 경제적 지원 방향은 다음과 같이 제시할 수 있다. 먼저 정부의 독점적인 인증제도를 본원적인 사회적기업의 의미와 실천을 훼손하지 않도록 개선해야 한다. 아울러 농촌지역에서 발견되는 다양한 자발적 노력들을 사회적 목적활동으로 인정할 필요가 있다. 둘째, 사회적기업에 대한 지원도 획일적인 인건비 지원보다는 구체적인 활동내용과 경영상의 애로점에 대응하여 차별적으로 주어져야 한다. 특히 관계 부처들의 사업들과 연계하여 사회적기업에 대한 투자를 지원할 수 있어야 하며, 사회적 투자기금을 조성해 금융조달에 대한 숨통을 틀 수 있도록 지원해야 한다. 농촌지역 사회적기업의 취약한 시장경쟁력을 보완해 줄 수 있는 보호시장의 제공, 바우처사업 등에 대한 참여 실적 등을 평가하여 경제적 보상으로 되돌려 주는 방안도 적극 모색되어야 한다. 셋째, 농촌지역 현실과 특성에 적합한 사업모델을 개발하고 보급해야 한다. 특히 농업 생산?유통?가공 사업에의 진출이 중요한데 시장경쟁이 심해짐에 따라 위험도가 높다. 따라서 지역 내의 인적?물적 연계를 활용한 사업모델 구축이 핵심과제이다. 문화예술활동은 당장은 수익구조를 맞추기 어렵지만 삶의 질 향상과 지역경쟁력의 원천이란 점에서 보호된 시장을 전제로 다양한 사업모델을 구상할 수 있을 것이다. Recently, while our concern about the social enterprise has grown, the anxiety of its sustainability has raised. However, the sustainability must be evaluated differently from general enterprises, because its social effects should be included in the social enterprise"s performance. The result of survey shows that business performances of social enterprises located in rural areas are generally balanced in terms of profit and cost. Their business volumes in terms of revenue are quite small by 440 million won. Their financial independency rate reached about 70 percent. This figure is over our expectation and is not low compared to foreign enterprises. Thirty percent of supports come from government supports and the weight of donation and mother body support is very low. The high level of government support can cause problems in the sustainability according to the change of government policies. The average number of employee of social enterprises is 22.5 persons. About the half of them comes from the vulnerable class. This fact shows that social enterprises contribute to the generation of employment and labor integration. Even though five persons of employee per 100 million won of revenue is higher than general business, the government policy for employment generation may have an effect on the unstability of business. We confirmed that the lower level of investment and the disadvantage of market conditions are difficulty in social enterprise business of rural areas. They cannot mobilize investments because of low profits and cannot easily approach to the financial institutes due to the lower level of security and profitability. Also, they have many disadvantages such as the lacks of capital and technology, inefficient labor, customers with low purchasing power, and the weak industrial infrastructures. Under these unfavorable conditions, we suggest several alternatives to support social enterprises in rural areas. First, government monopolistic certification system need to be modified in order not to damage the intrinsic meaning and practice of the social enterprise. Various voluntary efforts happening in the rural areas are needed to be admitted as a social goal directed activities. Second, government support should be provided differently according to substantial activities and business difficulties, not uniformed labor cost. Included are investment support connected with government departments" programs, the generation of funds, affirmative action of supplementing markets and etc. Third, business model should be developed and provided appropriate to the realistic characteristics of rural areas. The entry into agricultural production, distribution and processing is very important. However, it is very risky due to competitiveness. The core task is to build business model in connection with regional persennel and materials. The cultural arts activities would be a good business model in term of the quality of life and strong regional competitiveness.

Operating Conditions of Proton Exchange Membrane Fuel Cell Using Grafoil^{TM} as Bipolar Plates

박태현(Park, Taehyun),장익황(Chang, Ikwhang),이윤호(Lee, Yoon Ho),이주형(Lee, Juhyung),차석원(Cha, Suk-Won) 한국신재생에너지학회 2011 한국신재생에너지학회 학술대회논문집 Vol.2011 No.11

In this study, Grafoil^{TM} which has comparable electric resistance and chemical stability but is flexible, fragile, and cheap material was adopted as bipolar plates for proton exchange membrane fuel cell(PEMFC) having only one straight line flow channel. Because of its flexibility, pressurizations of cell with various pressures showed different operating characteristics compared to ordinary graphite-used PEMFC. While performances of both cells decreased as these were pressurized, investigation of ohmic and faradaic resistance by electrochemical impedance measurement indicated different tendency of change. Ohmic resistance of graphite-used cell increased with increasing pressure, which is reversed in Grafoil^{TM}-used cell. It is speculated that effective chemical reaction area is decreased with increasing pressure in case of graphite-used one, but because of flexible property of Grafoil^{TM}, gas diffusion layer in Grafoil^{TM}-used cell was well-activated. Different rate of change of faradaic resistances in both cells support this supposition. However, although optimum point of pressurization is found, it is required to investigate other operating conditions because of low performance compared to graphite-used cell.