어떤 수열의 합에 대한 두 가지 접근 방법

윤석주,한인기,Youn, Suk-Joo,Han, In-Ki 영남수학회 2008 East Asian mathematical journal Vol.24 No.5

Two proving methods are investigated. One method uses we mathematical induction and the other uses the progression of difference. Two methods are analysed and compared. As a result, we get a generalization of these series.

정맥류내 주사법에 의한 식도정맥류경화술의 임상적 경험

윤석주(Suk Joo Youn),정원재(Won Jae Jung),최상운(Sang Woon Choi),정현채(Hyun Chai Chung),김해련(Hae Ryun Kim),이효석(Hyo Suk Lee),윤용범(Yong Bum Youn),송인성(In Sung Song),김정룡(Chung Yong Kim) 대한내과학회 1987 대한내과학회지 Vol.33 No.5

N/A Between Nov. 1985 to Mar. 1987, we have administered endoscopic injection sclerotherapy to 54 patients who had bled from esophageal varices by intravariceal method and obtained following results: 1) In 27 patients who had reached complete sclerosis of esophageal varices, it took 4.7±1.9 (mean+SD) sessions (range 1-11 sessions) for complete sclerosing to occur. And taking the drop-out rate into consideration, complete sclerosis might be obtained in about 72% of patients with upto 7 sessions of treatment. 2) The failure rate of sclerotherapy representing death due to uncontrollable variceal hemorrhage and resort to operative management due to poor sclerosing response was below 10%. 3) Among those who have reached complete sclerosis, 11 patients were followed up for 1-11 months and in five of them (45%) further episodes of variceal bleeding were observed all of which were related to re-appearance of varices. 4) To prevent rebleeding from esophageal varices, it is important to maintain complete obliteration of varices and we recommend follow-up after complete sclerosis at 3 months` interval at least for the first one year. 5) Fatal complications have occurred at a rate of 1% on terms of treatment sessions in 5.5% of patients but with proper medical management no mortality has resulted. In conclusion, the endoscopic sclerotherapy using flexible endoscope and intravariceal injection method seems to be highly safe and may be an effective way of managing the patients with variceal hemorrhage both in acute control and long term prevention of variceal bleeding and therefore shou1d be considered as first line therapy prior to resort to operative measures.

초등학교 과학 교과서에서 자기학 교육과정에 대한 고찰

윤석주(Suk Joo Youn),이재일(Jae Il Lee) 한국자기학회 2009 韓國磁氣學會誌 Vol.19 No.2

We have investigated the magnetic education in elementary science of Korea. Text books and other related materials are analysed. Students learn playing with magnets in third grade and learn making electromagnets in sixth grade. Arrangement of topics are in accord with the historical development of electromagnetism in physics although the order is not well suited to other field of science. Teacher’s guide books need to be developed to consider various environments in school such as city and country, and rich and poor town. Several details in the science textbook are pointed out for better education. Overall course looks sound.

Cr₂Te₃에서 쿨롱 상관효과의 크기와 자기모멘트 크기의 계산

윤석주(Suk Joo Youn),권세균(Se Kyun Kwon) 한국자기학회 2006 韓國磁氣學會誌 Vol.16 No.2

Electronic and magnetic structure of Cr₂Te₃ have been studied, which is a material with complex magnetic structure. Density of states and magnetic moments show better agreement with experiments than LDA if they are obtained with the correlation effect of Crd electrons taken into account by the LDA+U method. In these calculations, the magnitude of the correlation effect is found to be 1.7 eV. It is shown that the magnitude of experimental magnetic moments of Cr atoms can be explained if the ferromagnetic states and the ferrimagnetic states have the same energy to be degenerate.

두 단단한 구의 충돌 문제의 풀이에 대한 연구

윤석주(Suk Joo Youn) 한국물리학회 2022 새물리 Vol.72 No.5

두 개의 단단한 구가 비탄성 충돌하는 문제에 대한 일반해를 구하여 반사 조건과 산란 조건에 적용하여 보았다. 반사 조건에서는 빛의 반사나 굴절에서 볼 수 있는 것과 비슷한 관계식이 얻어진다. 충돌조건에서 얻어진 매개 변수 γ의 값에 따라 충돌 문제를 세 가지로 분류할 수 있었다. 탄성 충돌에서 얻어진 결과는 기존의 것과 일치함을 확인하고 비탄성 충돌의 경우로 확장할 수 있었다. 산란각에 대한 식들은 간단하여 기억하기 편리하여 학습자가 충돌 문제를 학습하는데 도움을 줄 수 있다.<br/> A general solution to the collision problem of two inelastically colliding hard spheres is applied to the reflecting and scattering conditions. In the reflectig condition, simple equations that are similar to the reflection and refraction laws in optics were obtained. By contrast, in the scattering condition, the collision problem is classified according to the values of γ, which is a parameter in the result. Some results of the elastic collision can be confirmed and extended to inelastic cases. The obtained equations for scattering angle are simple to remember and expected to help students understand collision problems.

물리 교육용 가변형 회절 슬릿의 제작

오광택 ( Kwang-tek Oh ),윤석주 ( Suk Joo Youn ) 경상대학교 중등교육연구소 2019 현대교육연구 Vol.31 No.1

단일 실틈 및 다각형 구멍을 통과한 빛의 회절 특성을 쉽게 관찰할 수 있도록 슬릿 구멍의 형태와 크기를 조절할 수 있는 가변형 슬릿을 제작하였다. 이 장치는 면도날과 마이크로미터로 제작되었으며, 관찰하고자 하는 구멍의 형태에 따라 필요한 수의 면도날을 원형판에 장착하여 슬릿의 모양과 크기를 바꿀 수 있다. 마이크로미터는 면도날을 0.01 mm 단위로 움직일 수 있어 슬릿의 크기를 정교하게 변화시킬 수 있어서 연속적인 회절 무늬의 변화 과정을 관찰할 수 있다. 가변형 회절 슬릿 장치를 써서 단일 실틈, 삼각형, 사각형 슬릿에서 얻은 회절 무늬는 기존의 결과와 일치하고 있어 교육용 실험에 이용할 수 있는 가능성을 보여주었다. 따라서 본 가변형 슬릿은 학생들이 광학 회절과 간섭현상을 직관적으로 관찰하고 개념을 이해하는데 도움을 줄 것으로 기대된다. We have developed a variable slit of which the size and shape can be easily modified to get diffraction patterns for narrow single slits or polygonal slits. The instrument is made of a razor blade and a micrometer. The shape of the slits can be constructed by required number of variable slits on a circular plate according to the requirement of the experiments. The size of the slit can be adjusted in unit of 0.01 mm which is the resolution of the micrometers. So, it is possible to observe continuously changing diffraction patterns. Diffraction patterns from narrow single slits, triangle slits, and rectangular slits obtained in our experiments agree well with the well-known results from the literature, which shows that our variable diffraction slits works well. Therefore, the students can observe the variation of diffraction pattern as a continuous function of the slit size, which help student understand intuitively concepts in optical diffraction and interference.

초등학교 학생들의 자기장 개념 분석과 인지양식의 차이에 따른 대안실험의 효과

오광택(Kwang-Tek Oh),윤석주(Suk Joo Youn) 한국자기학회 2016 韓國磁氣學會誌 Vol.26 No.5

We have examined the perceptions of 6th grade elementary school students’ conceptions on the magnetic fields of a permanent magnet by cognitive style. Students’ conceptions on the magnetic fields of permanent magnet after the iron powder experiment are grouped into four models; Partial Distribution Model (PDM), Pole Separation Model (PSM), Homogeneous Distribution Model (HDM), and Field Model (FM). After the experiment to observe the magnetic field of the permanent magnet with compass, the students’ conceptions are grouped into three models; Pole Separation Model (PSM), Complex Homogeneous Distribution Model (CHDM), and Field Model (FM). And after the application of the alternative experimental method to observe the magnetic field with only one compass, students’ conceptions on magnetic field has been enhanced in both field-dependent and general-cognitive groups of students.

섬유아세포 증식에 대한 Phorbol myristate acetate의 효과

윤석주,박낭운,김인산,손건영,조준승 慶北大學校 醫科大學 1995 慶北醫大誌 Vol.36 No.1

목적 : 이 연구는 Phorbol myristate acetate (PMA)가 강력한 암촉진제로서 세포내 신호전달체인 protenin kinase C (PKC)의 활성화를 통하여 여러가지 작용을 나타낸다. 사람 두배수체인 섬유아세포와 불멸성 섬유아세포인 Swiss 3T3 세포의 증식 즉 DNA 합성에 대해 PMA의 미치는 효과와 이것의 PKC와의 관계를 조사하는데 있다. 재료 및 방법 : 사람 폐섬유아세포(HEL299) 및 Swiss 3T3세포를 밀생상태가 될때까지 배양한후 fetal vine serum이 없는 배지에서 48시간 두어 휴지기 상태로 만들어 필요한 시약과 [H^3]thymidine를 넣어 24시간 배양해서 세포내 DNA 합성에 이용된 [H^3]thymidine의 방사능을 측정하여 비교하였다. 결과 : 사람 및 Swiss 3T3 섬유아세포의 DNA 합성은 PMA단독투여 때는 약2배로 증가되었으나 colchicine 혹은 insulin을 함께 투여하면 그 양상은 달랐다. 즉 PMA는 Swiss 3T3 세포에서 insulin에 의한 DNA 합성 증가작용을 더욱 촉진시켰으나, 사람의 섬유아세포에서는 insulin이나 colchicine에 의한 DNA합성 증가를 오히려 억제하였다. 사람의 섬유아세포에 비활성 phorbol ester인 4α-phorbol-12, 13-didecanoate(4α-PDD) 단독 투여하니 PMA 무여군과는 달리 DNA 합성이 대조군과 별 차이가 없었으며, colchicine에 의한 DNA 합성증가에도 별로 영향을 미치지 않았다. Swiss 3T3 세포에 비교적 선택적으로 PKC 활성을 억제하는 staurosporine을 농도를 증가시키면서 투여하니 PMA에 의한 DNA합성 증가효과는 감소되었다. 결론 : PMA는 사람 섬유아세포나 Swiss 3T3 세포에 약간의 증식효과를 가지나 세포 자극제에 의한 DNA 합성 증가효과에 대해서는 세포의 종류 및 상태에 따라 다른 결과를 나타내었다. 또한 PMA의 효과는 PKC를 통하여 일어남을 시사하였다. Proliferation of fibroblasts around the damaged tissue plays a key role in the wound healing and the development of tissue fibrosis. Phorbol myristate acetate (PMA) is known to be a potent tumor promoter and its intracellular receptor, protein kinase (PKC) is known to play important roles in many signaling pathways, including those involved in cell proliferation. In cultured human diploid tang fibroblasts and Swiss 3T3 cells, the effects of PMA on the DNA synthesis and the involvement cf PKC in its effects were studied. PMA alone stimulated DNA syntheis by the both cells slightly. However, the treatment of the both cells with PMA resulted in an opposite effect on the DNA syntheis stimulated by colchicine and/or insulin. PMA inhibited DNA synthesis in human fibroblasts stimulated by insulin and colchicine, whereas PMA potentiated insulin-stimulated DNA synthesis in Swiss 3T3 cells. 4α-phorbol-12, 13-didecanoate(4α-PDD), known to be inactive for PKC, was without effect in DNA synthesis by human fibroblasts in the either absence or presence of colchicine. Staurosporine, a relatively specific inhibitor for PKC abolished the effect of PMA on DNA synthesis in Swiss 3T3 cells in the presence of insulin. These results suggest that PKC is involved in the regulation of DNA synthesis in fibroblasts but its outcome may be different according to the culture conditions and the cells used.