수도권 일부 초등학교 고학년 학생의 구강보건에 관한 지식과 태도, 행동의 상관성 연구

김석환,김재홍,김지환,Kim, Seok-Hwan,Kim, Jae-Hong,Kim, Ji-Hwan 대한치과기공학회 2011 대한치과기공학회지 Vol.33 No.4

Purpose: The purpose of this study was to obtain data that can be utilized in the planning of oral health education plan, by surveying the correlation between oral health knowledge, attitude, and behavior among high grade students elementary school in some regions of the metropolitan. Methods: The subject of this study through the survey of the recognition of the oral health, a questionnaire survey was conducted for 548 male and female students who were in the 4th, 5th, 6th grade of elementary school in some regions of the metropolitan. Statistical analysis was conducted using the SPSS 12.0 with t-test, ANOVA, and correlation. Results: Knowledge of oral health was very high. Correct attitudes and positive behavior were indicated. There was a significant difference in oral health knowledge according to school year and parents' dental condition(P<.05). The student one recording oral health behavior degree where the oral health knowledge is high appears highly, considers statistically the difference which it was visible. Positive correlation was significantly observed among oral health knowledge, attitudes, and behavior. Especially, attitudes and toothbrush method were highly correlated(r=.853). Conclusion: Oral health program through the elementary school students and their parents for the development of proper oral health care education programs continue to be made should be considered.

Ti(C, N)계 써메트의 유심구조 형성거동

김석환,Kim, Suk-Hwan 한국분말야금학회 2006 한국분말재료학회지 (KPMI) Vol.13 No.1

Model experiment was introduced to obtain the formation of a core/rim structure by only liquid phase reaction in Ti(C, N)-based cermet alloys. Infiltrated Ti(C, N)-Ni, $MO_2C-Ni$, and TaC-Ni cermets were bonded to sandwiched specimen by heat treatment $1450^{\circ}C$ for 5hr. With nitrogen addition, both (Ti, Mo) (C, N) and (Ti, Ta) (C, N) rim structure was nucleated around comer of cuboidal Ti(C, N) core. However, equilibrium shapes of(Ti, Mo) (C, N) and (Ti, Ta) (C, N) rim were different possibly due to the effect of interface energy. The core/rim and rim! binder interfaces were parallel to each other with TaC addition, while rotated to each other with $MO_2C$ addition.

Effects of Constituents in CNT Pastes on the Field Emission Characteristics of Carbon Nanotubes

김석환,이동구,Kim, Suk-Hwan,Lee, Dong-Gu The Korean Institute of Electrical and Electronic 2011 전기전자재료학회논문지 Vol.24 No.3

Carbon nanotubes (CNTs) have been significantly used for the field emitters for display applications. However, the lifetime of CNT emitters which are formed by screen printing technique is not guaranteed yet, because the constituents in CNT paste affect the lifetime of CNTs. The CNT pastes for screen printing are normally composed of organic vehicles (nitro cellulose, ethyl cellulose, etc) and additives (glass frits, indium tin oxide (ITO), etc) with CNTs. In this study, the effects of constituents in CNT pastes on the lifetime and emission characteristics of CNTs were investigated by thermal and electrical analysis. Use of glass frits worsened the lifetime and electron emission of CNTs. However, an addition of ITO to CNT paste rather improved the lifetime of CNTs. Degradation of CNTs was small when nitro cellulose was used in CNT paste as an organic vehicle.

Selenium이 MPTP(1-methy-4-phenyl-1,2,3,6-tetrahydropyridine)에 의해 유도된 생쥐의 신경독성에 미치는 영향

김석환,이주연,김여정,강혜옥,이항우,최종원,Kim Seck-Hwan,Lee Joo-Yeon,Kim Yeo-Jeong,Kang Hye-Ok,Lee Hang-Woo,Choi Jong-Won 한국생명과학회 2006 생명과학회지 Vol.16 No.2

MPTP에 의해 유도된 Parkinsonism에 대한 selenium의 보호효과와 그 보호작용에 대한 항산화적 해독기전을 조사하기 위하여 MPTP 10mg/kg을 6일간 주사하고 selenium (25, 50, 100 ${\mu}g/kg$)을 10일간 경구 투여하였으며 처음 6일간은 selenium와 MPTP를 병용 투여하였다. 실험동물을 마지막으로 selenium을 투여하고 24시간 후에 치사시켜 일반적인 독성과 항산화 방어능과 관련된 지표성분과 monoamine oxidase와 같은 신경생화학적인 지표성분들을 뇌조직에서 측정하였으며 그 결과 다음과 같은 결론을 얻었다. 우선 MPTP를 투여함에 따라 운동능력이 저하되던 것이 selenium을 투여함에 따라 운동능력이 증가되었으며, 이러한 결과의 기전은 selelnium을 투여함으로써 MPTP를 $MPP^+$로 대사시키는 MAO-B의 활성을 억제하였으며 $MPP^+$에 의해 유도된 신경독성에 대한 selenium의 보호 효과는 selenium을 투여함으로써 활성산소 해독계인 SOD, catalase, glutathione peroxidase의 활성을 증가시키기 때문인 것으로 사료된다. This study is investigated the effect of selenium against neurotoxicity induced by MPTP(1-methy-4-phenyl-propion-oxypiperidine) in mice. In order to demonstrate neuroprotective activity of selenium, mice were administrated orally with selenium(25, 50, 100 ${\mu}g/kg$, once/day) for 10 days, and MPTP(10 mg/kg) was injected subcutaneously into the mice for 6 days from the beginning 1hr before selenium treatment. Test of rota road activity was inhibited by treatment with selenium in MPTP-induced neurotoxicity group when compared to MPTP treatment group in normal mice. Monoamine oxidase(MAO)-B activity and cerebral lipid peroxide content were significantly decreased in the treatment of selenium in MPTP-induced neurotoxicity group when compared to MPTP treatment group in normal mice and MAO-A was not affected. Activities of cerebral superoxide dismutase, catalase and glutathione peroxidase were significantly increased in the treatment of selenium in MPTP-induced neurotoxicity group when compared to MPTP treatment group in normal mice. These results suggest that selenium might be estimated the result from the cooperative action of its inhibitory effect on monoamine oxidase-B with that of the enhancement of antioxidant(SOD, catalase, GSH-Px) defence ability.

한국전통건축의 좋은 느낌(5) - 종묘

김석환,Kim, Seok-Hwan 대한건축사협회 2001 建築士 Vol.2001 No.7

GRAPH-EXPO 78을 돌아 보고

김석환,Kim, Seok-Hwan 한국과학기술단체총연합회 1979 과학과 기술 Vol.12 No.4

살모사 교상 후 발생한 범발성 혈관내 응고장애 2례

김석환,최세민,오영민,박규남,이원재,최경호,Kim, Suk-Hwan,Choi, Se-Min,Oh, Young-Min,Park, Kyu-Nam,Lee, Won-Jae,Choi, Kyung-Ho 대한임상독성학회 2006 대한임상독성학회지 Vol.4 No.2

Our records include two cases of DIC in snakebite patients. One patient, who was 48-years old, was bitten in his left ankle 3 days before admission to our hospital. Initial symptoms were painful swelling, extensive ecchymosis, and persistent bleeding at the bite site. He visited and was admitted to a local hospital, but his condition did not improve with supportive care that included a single dose of antivenin. He was transferred to our hospital. His condition was compatible with DIC. We tried multi-dose antivenin therapy and blood product transfusion. At the seventh hospital day, the patient's symptoms were completely resolved. The other patient, who was 75 years old, was bitten in his right thumb. Initial symptoms were painful swelling of the right arm and persistent bleeding at the bite site, and within minutes of hospital admission, the patient experienced massive hematochezia. We peformed laboratory tests, the results of which were compatible with DIC, and the next day a sigmoidscopic examination showed ischemic colitis. We administered multi-dose antivenin therapy and blood product tranfusion. At the third hospital day mild anemia still existed, but the patient's clinical condition was improved. No signs or symptoms of gastrointestinal bleeding were observed. In these two cases, multi-dose antivenin therapy and transfusion effectively resolved symptoms of DIC. Platelet concentrate transfusion was required only for acute thrombocytopenia. After resolution of DIC, platelet counts were returned to normal ranges within a few days. The authors propose that multidose antivenin therapy and coagulation factor transfusion might be useful for improving coagulopathy in snakebite patients.

통신시스템의 데이터 전송선로에 대한 연구

김석환,이규정,허창우,Kim Soke-Hwan,Lee Kyeu-jung,Hur Chang-wu 한국정보통신학회 2005 한국정보통신학회논문지 Vol.9 No.6

현재 통신시스템에서는 FPGA를 사용하여 여러 가지 로직을 구현하고 있다. 본 논문에서는 데이터 전달 특성을 분석하고 신호의 노이즈와 데이터 손실을 방지하기 위하여 10층의 PCB(Printed Circuit Board)를 만들었다. FPGA에 클럭과 64bit의 데이터를 동기 시켜 전송선로의 길이의 변화와 입력된 클럭의 주파수 변화에 따른 최대 안정된 데이터 전달속도와 전송선로의 길이를 알아보았다. 제작된 PCB보드에서 FPGA의 출력 핀에서 출력포트 사이의 전송선로 길이는 13cm이며 확장된 테스트용 전송선로 보드의 길이는 30cm, 60cm, 120cm이다. 그러므로 전송선로의 길이를 13cm, 43cm, 73cm, 133cm간격으로 측정하였으며, 데이터 전송특성에 대한 클럭 주파수는 100MHz, 50MHz, 100MHz, 125MHz, 150MHz로 나누어 측정하였다. 데이터 전달 특성에서 125Mbps까지는 불가능 하지만 전송선로의 길이가 30cm일 경우 최대 100Mbps까지 안정하게 데이터를 전달할 수 있었다. FPGA has been widely used in communication system. In this paper, we made 10 layers PCB on protection of signal noise and data lose with FPGA. We analyzed about change of the data transmission speed and length according to input frequency. The length of transmission line from FPGA's output-pin to output-port on PCB board is 13cm and extended lengths for test are 30cm, 60cm and 10cm. We knew that data can be stably transmitted to 100Mbps at transmission line length of 30cm.

건축기행 - 양동마을 답사를 마치고…

김석환,Kim, Seok-hwan 대한건축사협회 2014 建築士 Vol.2014 No.1

지난 11월 16일 서울건축사 건축답사 및 사진 동호회(회장 김선양) 행사로 영동마을을 다녀왔다. 2012년 12월 발족한 이 회에서는 두 달에 한 번씩 전국 각지의 전통건축 답사를 진행해오고 있는데 건축 전문가인 회원들이 함께 소중한 건축문화 유산을 돌아보며 그 가치를 살펴보는 유익한 시간을 가져왔다. 이번 답사지는 지난 10월 수원화성 답사 때 필자가 추천하였는데 금번 나의 졸저 "한국전통건축의 좋은느낌"의 개정판 출판을 계기로 현장 설명을 맡기로 하여 적절한 답사 경로를 알아보기 위해 사전답사도 다녀왔었다.

훈데르트 바서의 환경과 건축

김석환,Kim, Seok-Hwan 대한건축사협회 2006 建築士 Vol.2006 No.5