이종마찰압접재의 변형 및 균열 성장 거동 : STS304 와 SM15C재를 중심으로 For STS304 and SM15C

오정국,오환섭,박준건 조선대학교 동력자원연구소 1997 動力資源硏究所誌 Vol.19 No.1

In this study, behavior of crack growth and fracture under static tensile load in friction welded dissimilar materials, and necking phenomenon occuring at tensile yeilding point is shown. Crack is observed in heat affected zone including fine ferrite region of SM15C and heat affected zone of STS304. Plastic flow was occured by friction welding process, so direction of crack is inclined with welded surface. Fracture behavior of similar material is subject to joint of void, but dissimilar material is liable to joint of micro crack. Fibrous zone with the view of macroscope and dimple pattern with the view of microscope is observed at fracture surface.

국내 말라리아 퇴치사업의 현황 분석과 개선 방안

박재원,홍지영,염준섭,조성래,오대규 대한감염학회 2009 감염과 화학요법 Vol.41 No.1

Background : Vivax malaria had spread rapidly in areas adjacent to the Demilitarized Zone to reach more than 4,000 cases in 2000 in the Republic of Korea (ROK). After year 2000, annual cases decreased rapidly to reach less than 1,000 cases in 2004. However, the number increased again since 2005. Epidemiological characteristics of vivax malaria in the ROK are different before and after 2000. This article was aimed to evaluate the current status of malaria elimination project in the ROK for providing suggestions for its improvement. Materials and Methods : We analyzed the total reported malaria cases during 2005 to 2007 and reviewed the record on the malaria eradication project performed by the authorizations including the Korea Center for Disease Control and Prevention. Results : During 2005 to 2007, 45% of all the vivax malaria occurred in patients living in the non-prevalent areas; the interval between first symptom onset and diagnosis was longer in the non-prevalent areas compared to that in the prevalent areas. Education and publicity on malaria has not been properly performed in the non-prevalent areas. The military didn't take part in the control of the malaria infected discharged soldiers, most of whom might have been infected with malaria during their military service. Conclusion : For the efficient control of malaria and thus improving the effectiveness of the elimination project education and publicity on malaria in the non-prevalent areas should be strengthened and cooperation between private and military sector regarding the ex-soldiers infected with malaria is essential, In addition, there should be bilateral communication among malaria-related teams within the Korea Centers for Disease Control and Prevention and also among all the malaria-related sectors. Furthermore a common database on malaria patients and vector mosquitoes should be formed to grant access to all the malaria-related sectors, Improvement on report and surveillance system is also necessary.

티타늄 표면에 대한 배양 골수세포와 치은 섬유아세포의 생체적합성

오충영,박준봉,권영혁,이만섭 慶熙大學校 齒科大學 1995 慶熙齒大論文集 Vol.17 No.2

The purpose of this study was to evaluate the response in aspect of attachment and growth rate of osteablasts and human gingival fibroblasts to the commercially pure titanium(CP titanium) and titanium alloy(Ti-6A1-4V) that are used widely as implant materials, and to obtain the basic information to ideal implant materials. In this study, commercially pure titanium in first test group, titanium alloy(Ti-6A1-4V) in second test group, cobalt-chromemolybdenum alloy(Co-Cr-Mo alloy) in positive control group, and tissue culture polystyrene plate in negative control group were used. The results of this study were as follows. 1. Bone marrow cells cultured on CP titanium and Ti-6A1-4V showed significantly greater attachment and growth rate(p<0.05) compared to Co-Cr-Mo alloy in each time. 2. There were no significant differences(p>0.05) in attachment and growth rate of bone marrow cells cultured on GP titanium and Ti-6A1-4V or tissue culture plate. 3."Most bone marrow cells cultured on CP titanium, Ti-6A1-4V and tissue culture plate were attached well to each substratum in first 2days, and then, grew at higher growth rate. On the other hand, some cells cultured on Co-Cr-Mo alloy failed to attach in first 2 days, and then, attached cells grew at lower growth rate than other groups. 4. Attachment and growth rates of gingival fibroblasts cultured on CP titanium and Ti-6A1-4V showed no significant differences(p>0.05) compared to Co-Cr-Mo alloy in 2 days, but significantly greater increase(p<0.05) in 5 and 9 days. 5. There were no significantly differences(p>0.05) between growth rates on gingival fibroblasts cultured on CP titanium, Ti-6A1-4V and tissue culture plate in 2 and 5 days, but a significant lower growth rate(p<0.05) on CP titanium and Ti-6A.1-4V versus tissue culture plate. 6. Some gingival fibroblasts cultured on all specimen groups failed to attach, but attached cells grew well especially on CP titanium, Ti-6A1-4V and tissue culture plate. 7. There were no significant differences(p>0.05) between growth rates of both bone marrow cells and gingival fibroblasts cultured on CP titanium and Ti-6A1-4V. As a result of this study, both commercially pure titanium and Ti-6AI-4V showed excellent biocompatibility and there was no significant difference in the cellular response to the both metals. Bone marrow cells cultured on each substratum showed significantly greater growth rate and responded sensitively to cytotoxic effects of metal surfaces compared to gingival fibroblasts. Considering cell response to the substrate, it was likely that the composition itself of titanium metals have no significant effects on the biocompatibility. Further study need to be done to evaluate the influence of surface characteristics on cellular responses.

스포츠 소비가치와 생활만족

오준석,박상주 龍仁大學校 體育科學硏究所 2003 體育科學硏究論叢 Vol.13 No.2

The purpose of this study was to investigate the effects of the value types for sport consumption on life satisfaction. To attain the purpose, the value types for sport consumption were divided into value in use, value in exchange and value in discrepancy based on needs of consumption. Life satisfaction was also divided affection, unification, attainment, the sense of self, optimistic attitude to past, present and future life. The subjects of this study were 450 men and women over twenties that do sports activities at sport center in Seoul city. The 393 collected questionnaires held validity. Among 450 questionnaires, 57 insincere questionnaires were ruled out. Also, trust degree of these collected questionnaires was verified by Cronbach's α, and trust degree of the value types for sport consumption were .7648, trust degree of life satisfaction was .7541. These numerical value meant satisfactory trust degree. Through SPSS Win 11.0 for analyzing these data, t-test, One-way ANOVA, LSD post-verification, Correlation and Multiple linear regression analysis were used as statistics techniques. All statistical data were tested with p<.05. The findings of this study were as follows: 1. There were statistically meaningful differences at 5% level in the value types for sport consumption. Especially the value types for sport Consumption with sex showed meaningful difference in value in discrepancy. Also the value types for sport consumption with age showed difference in value in exchange and sport participation term shows difference in value in use. 2. There were statistically meaningful differences at 5% level in life satisfaction. Especially life satisfaction with income showed difference in attainment and the sense of self, life-satisfaction with occupation showed difference in the sense of self and optimistic attitude. Also sport participation term showed difference in attainment. 3. There was a positive correlation of value in exchange, value in use and value in discrepancy in order between the value types for sport consumption and the affection to lie. 4. There was a negative correlation of value in exchange, value in discrepancy in order between the value types for sport consumption and the attainment. 5. There was a positive correlation of value in use between the value types for sport consumption and the attainment. 6. There was a positive correlation of value in use between the value types for sport consumption and the sense of self. 7. There was no correlation of value in use, value in exchange and value in discrepancy between the value types for sport consumption and the optimistic attitude.

이종접합재 접합 계면근방 균열의 응력 및 파괴특성

오정국,차용훈,오환섭,박준건,박경식 朝鮮大學校 機械技術硏究所 1998 機械技術硏究 Vol.1 No.1

현재까지 이종마찰압접재의 강도측정은 실험 (7)-(15)에 의해 구해져 왔다. 하지만 최근 이종마찰압접재의 효율성을 인정하여 여러 실용 부품에 응용하려는 연구가 한창 진행중이다. 이종마찰압접재에 대한 저자들(1)-(6)의 기초실험결과 일반적인 단종재와는 상이한 파괴거동(3)이 관찰되었고, 파괴역학적인 관점에서 정성적인 data 확보가 필요하게 되었다. 따라서 본 연구에서는 인장시험시 이종마찰압접재의 접합강도와 미소균열들에 의한 파괴거동을 파괴역학적 관점에서 해석적으로 고찰하여 보고자 경계요소법(BEM ; Boundary Element Method)을 이용하여 접합계면을 포함하는 접합부를 중심으로 계면상의 응력분포와 계면의 중앙에 결함이 균열로써 존재하는 경우의 응력분포와 인장시험시 열영향부에서 관찰된 균열의 모델링을 통한 균열선단에서의 응력해석을 행하였고, 그 결과 얻어진 중요한 내용을 요약하면 다음과 같다. 계면의 중앙에 균열이 존재하는 접합계면의 표면부에서 응력의 특이성이 발생하며 탄성계수의 비가 증가할수록 특이성이 증가함이 관찰되었다. 탄성계수의 비가 일정한 경우 균열의 크기가 변화하여도 계면의 표면부에서 발생하는 특이성은 거의 같은 값을 갖게 되며, 탄성계수의 비가 증가할수록 표면부의 응력 특이성의 크기는 증가한다. 이종마찰압접재의 인장시험시 관찰된 균열을 모델링 하여 해석한 결과 최대 응력 기준으로 살펴볼 때 인접한 균열선단에서의 응력분포는 균열을 합체시키는 방향으로 작용함을 알 수 있다. In this study stress distribution on the interface and stress near tip of the sub-interface crack in the dissimilar friction welded material is analyzed by using of BEM( Boundary Element Method). Stress singularity near surface of model to analyze is observed for various crack length and ratio of elastic modulus. Tensile and shear stress distribution near two neithbor sub-interface crack tips are analyzed. Existance of singularity near surface on the interface is particular situation so that we need to investigate for dissimilar friction welded materials by means of numerical analysis method.

외과계 감염증에 대한 Sulperazon(Sulbactam/cefoperazone) 및 Cefoperazone의 임상효과 비교연구

박규주,노동영,김상준,권오중,정중기,홍인규 대한화학요법학회 1990 대한화학요법학회지 Vol.8 No.2

Despite recent advances in development of antibiotics and antiseptic techniques, infection still remains to be one of the major problems in the surgical field. Due to development of bacterial resistance to commonly used antibiotics, there is always a need to develop a new antimicrobial agent which would overcome such resistance. Sulperazon (Sulbactam/Cefoperazone) is a combination drug of potent β-lactamase inhigitor, sulbactam, and cefoperazone which has broad antibacterial spectrum, which was developed to combat against β-lactamase producing microorganisms. In an effort to evaluate the efficacy and safety of sulperazone, we have randomly divided 40 patients (12 with perforated appendicitis, 10 with peritionitis, 6 with GB empyema, 6 with periproctal abscess, 3 with wound infection, 1 liver abscess, 1 pancreatic abscess, and 1 acute cholangitis) into 2 groups (20 patients in each group). One group received daily dose of 2 to 3 grams of sulperazon and the other group received daily dose of 2 to 3 grams of cefoperazone. Following results were obtained : 1. Clinical effect of sulperazon was cure in 16 patients (80%), improvement in 3 patients (15%), compaired to cure in 14 patients (70%), improvement in 4 patients (20%) for the cefoperazone group. 2. Using disc diffusion method, sulperazon was sensitive to all of the isolated microorganisms except β-hemolytic streptococci, which was moderately sensitive. Cefoperazone was sensitive to only E. coli, Pseudomonas aeruginosa and Serratia. 3. Microbiological effect of sulperazon was eradication of offending microorganisms in 16 patients (80%), compared to 14 patients (70%) in Cefoperazone group. 4. Overall clinical efficacy of sulperazon was 95%, compared to 80% for cefoperazone. 5. Adverse effects due to sulperazon was nausea and diarrhea which occurred in 1 patient respectively. 2 patients receiving cefoperazone experienced diarrhea. It can be concluded that sulperazon is a safe and effective antibiotic agent which can be used in surgical infection patients.

이종마찰압접재 계면의 기계·금속조직학적 거동 및 파면특성 : STS304와 SM15C재를 중심으로 For STS304 and SM15C

오환섭,박경식,박준건,오정국,백영남 慶熙大學校 材料科學技術硏究所 1998 材料科學技術硏究論集 Vol.11 No.-

In this study is behavior of crack propagation and fracture under static tensile load, shear load, rotary bending fatigue load in friction welded dissimilar materials. Crack was observed in fine ferrite zone of SM15C and heat affected zone of STS304. Plastic flow was occured by friction welding process, so direction of crack is inclined with welded surface. Fatigue fracture most occurred in SM15C heat affected zone around interface. Fibrous zone with the view of macroscope and dimple pattern with the view of microscope were observed at fracture surface. Result is more metal micrstructure dependence than stress dependence by mechanical and metallic mechanics.

병렬 처리 모델의 성능 분석에 관한 연구

박준호,오주환 경운대학교 산업기술연구소 2002 産業技術硏究論文誌 Vol.5 No.1(A)

In this paper, as a performance analysis of parallel processing, a static data flow model and a Von Neumann model is used. Simulations are performed and the results are analyzed. The CPI and MIPS are used to analyze the performance of two models at a real time speed. In general, Von Neumann models make well use of locality, but data-flow models have overheads that are due to producing token and no use of locality.

토끼에서 근육주사시 입자 크기에 따른 amoxicillin의 비교 약물동태학

박승춘,윤효인,오태광,장범수,배순이,조준형,정상희,이내경,김민규 충남대학교 수의과대학 동물의과학연구소 1998 動物醫科學硏究誌 Vol.6 No.-

To investigate the pharmacokinetic difference between the two amoxicillin (AMX) particles in rabbits after intramuscular injection (i.m.), both of AMX-S (particle size: 10 ㎍) and AMX-L (particle size: 100 ㎍) were injected into New Zealand White rabbits (1.2±0.3 ㎏) at a dose rate of 10 ㎎/㎏ of body weight. In this study, serum AMX concentrations were detected by microbiological assay with E. coli BE 1186 which shows high antibiotic sensitivity. After i.m. administration, AMX-S and AMX-L were best fitted as 1-compartment model with the absorption and elimination phase. The biological half-life (T_1/2, _k10) of AMX-S is 4.06±1.09 h and that of AMX-L 4.76±0.69 h. The serum maximal concentration time (T_max) of AMX-S and AMX-L were 0.88±0.17 h and 0.77±0.11 h, respectively. Maximal AMX concentration (C_max) (AMX-S: 5.71±0.62 ㎍/㎖, AMX-L: 5.04±0.25 ㎍/㎖) in serum showed a significant difference (p<0.05). In terms of bioequivalance, however, there was no difference between the two AMX's after i.m. injection in the basis of C_max and AUC.

랫드에서 신우황청심원의 급성 및 아급성독성시험

오승민,남혜윤,김준수,연제덕,신대희,이진영,박대규,조명행,정규혁 성균관대학교 약학연구소 1998 成均藥硏論文集 Vol.10 No.1

The acute and subacute toxicity of New Woohwangchungsimwon(NWCH) which was used l-muscone as substitutive material of musk were investigated in S.D. rats. In intraperitoneal acute toxicity test, rats(Sprague-Dawley, SPF) were injected intraperitoneally with dosages of 0, 540, 750, 1,070, 1,500 and 3,000 ㎎/㎏. Body weights were significantly decreased at 540 ㎎/㎏ dose group in both sexes and abnormal autopsy findings were founded in both sexes at all treated groups. Intraperitoneal LD_50 of NWCH was 812.3 ㎎/㎏ in male and 872.3 ㎎/㎏ in female rats. In the subacute toxicity study, NWCH was administrated orally to both sexes of rats for 4 weeks as several doses(0, 320, 800 and 2,000 ㎎/㎏). There were neither dead animals nor significant changes of body weights during the experimental period. In addition, no differences were found between control and treated groups in clinical signs, urinalysis, hematology, serum biochemical analysis, and other findings. Above data strongly suggest that no observed adverse effect level of NWCH might be over 2,000 ㎎/㎏/day in this study.