The Longitudinal Trend of Cardiac Surgery in Korea from 2003 to 2013

Lee, Kyeong Soo,Kim, Chang Suk,Park, Jong Heon,Hwang, Tae Yoon,Kim, Sang Won,Sim, Sung Bo,Lee, Kun Sei The Korean Society for Thoracic and Cardiovascular 2016 The Korean Journal of Thoracic and Cardiovascular Vol.49 No.sup

Background: The purpose of this study was to investigate longitudinal changes of the utilization of operational and surgical medical care inside and outside a metropolitan area over 10 years, analyzing the residential areas of patients and the locations of medical facilities for major cardiovascular surgery. Methods: Data analysis was conducted by classifying the addresses of patients and the locations of medical care facilities of metropolitan cities and provinces, using data from the National Health Insurance Corporation from January 2003 to December 2013. Results: There is serious concentration of major heart surgery to medical facilities in Seoul; this problem has not improved over time. There were differences in percentages of surgical procedures performed in the metropolitan areas according to major diseases. In the case of Busan and Daegu provinces, at least 50% of the patients underwent surgery in medical facilities in the city, but there are other regions where the percentage is less than 50%. In the case of provinces, the percentage of surgical procedures performed in medical facilities in Seoul or nearby metropolitan cities is very high. Conclusion: Policies to strengthen the regional capabilities of heart surgery and to secure human resources are required to mitigate the concentration of patients in the capital area. Many regional multi-centers must be designated to minimize unnecessary competition among regional university hospitals and activate a win-win partnership model for medical services.

원통 연삭에서 가공 능률 향상을 위한 연삭 저항의 측정에 관한 연구

김원일,이진,이윤경,왕덕현,이상복,이관철,문원길 경남대학교 공업기술연구소 2000 硏究論文集 Vol.18 No.-

본 연구에서는 원통 연삭 가공에서 가공 능률 향상을 위한 연삭 저항을 측정하고자 연삭 가공 중에 발생하는 연삭 저항의 추이를 확인하였고 다음과 같은 결과를 얻었다. 숫돌과 공작물간의 연삭 강성은 공작 속도의 증가에 따라 지지계의 강성이 높은 경우 증가하였고 절삭 깊이와 연삭 숫돌의 속도에는 연삭 강성이 감소하는 경향을 보였다. 또한 총합 강성은 공작 속도, 절삭 깊이 및 연삭 숫돌의 속도 증가에 따라 지지계의 강성이 높을 수록 증가하였다. 연삭기의 강성 변형과 가공 능률에 영향을 주는 값으로 연삭 강성비는 지지계의 강성이 높을 수록 감소하였다. In this study, the measurement of grinding resistance to improve grinding efficiency in cylindrical grinding was studied and the following conclusions could be obtained. Relation grinding wheel and workpiece, grinding stiffness increases according to increase of work speed for high machine stiffness and decreases depth of cut and grinding wheel speed. Also, resultant stiffness increases high machine stiffness according to increase work speed, depth of cut and grinding wheel speed. The values of the effect stiffness deflection in grinding machine, grinding stiffness ratio decrease according to high machine stiffness.

조선후기 천문학자 이덕성의 생애와 천문활동

안영숙,민병희,서윤경,이기원,AHN, YOUNG SOOK,MIHN, BYEONG-HEE,SEO, YOON KYEONG,LEE, KI-WON 한국천문학회 2017 天文學論叢 Vol.32 No.2

The life and astronomical activity of Lee Deok-Seong (李德星, 1720-1794) was studied using various historical sources, including the astronomical almanac, Seungjeongwon-Ilgi (Daily records of Royal Secretariat of Joseon dynasty), and the Gwansang-Gam's logbooks during Joseon dynasty (A.D. 1392-1910). We present the results of the study including the following main findings. First, from the investigation of Lee's family tree, we find that a number of his relatives were also astronomers, notably Samryeok-Gwan (三曆官, the post of calendrical calculation). Second, we find that he took part in the compilation of an annual astronomical almanac over a period of at least 16 years. His major achievements in the astronomy of the Joseon dynasty were to establish a new method of calendar-making calculation and to bring astronomical materials to the Joseon court through a visit to China. The Joseon dynasty enforced the Shixianli (時憲曆, a Chinese calendar made by Adam Shall) in 1654 without fully understanding the calendar. So an astronomer and an envoy were dispatched to China in order to master the intricacies of the calendar and to learn as much of Western science as was available in that time and place. Lee Deok-Seong worked at the Gwansang-Gam (觀象監, Royal Astronomical Bureau) during the reigns of King Yeongjo (英祖) and Jeongjo (正祖). As best as we can ascertain in relation with the calculations in the Shixian calendar, Lee visited China four times. During his trips and interactions, he learned a new method for calendar-making calculations, and introduced many Western-Chinese astronomical books to Joseon academia. Lee greatly improved the accuracy of calendrical calculations, even while simplifying the calculation process. With these achievements, he finally was promoted to the title of Sungrok-Daebu (崇祿大夫), the third highest grade of royal official. In conclusion, history demonstrates that Lee Deok-Seong was one of the most outstanding astronomers in the late-Joseon dynasty.

탄소 나노튜브의 전계방출 특성

이경원,김은미,권민철,김용,이재열,박홍준 동아대학교 기초과학연구소 2000 基礎科學硏究論文集 Vol.17 No.1

본 연구에서는 emitter와 collector 사이의 간격과 current density 대 electric field (J-K)특성을 초점으로 카본나노튜브의 전계방출 특성을 조사하였다. 카본 소스로 CH4, 촉매 및 희석가스로서 NH3를 사용하고 HFCVD를 이용하여 실리콘 위에 카본나노튜브를 성장하였다. 나노튜브의 지름이 20-40nm이고 길이는 15㎛이다. I-V곡선에서 onset voltage는 Vons=3.36V/㎛이고, 2.5V/㎛ 의 전기장에서 8mA/cm2이상의 높은 전류밀도 특성을 보였다. Fowler-Nordheim 그래프를 그려서 팁의 특성을 나타내는 β값을 계산하였다. We report the field emission properties of carbon nanotube, focusing on current density versus electric field (J-F) characteristics and the spacing between the emitter and collector. We grow carbon nanotubes on sillicon using hot-fillament chemical vapor deposition, using CH4 gas as the carbon source and NH3 gas as the catalyst and dilution gas. Nanotubes are distributed from 20 to 40nm in diameter and 15㎛ long. Onset field of the field emission is 3.36V/㎛ and the current density is 8mA/cm2 at an electric field of 2.5V/㎛. A Fowler-Nordheim plot was made. Field enhancement factor β is calculated.

외상후 발작의 위험인자에 대한 조사

이재학,배학근,윤석만,도재원,이경석,윤일규,최순관,변박장 순천향의학연구소 2001 Journal of Soonchunhyang Medical Science Vol.7 No.1

Risk Factors for Posttraumatic Seizure The authors evaluate the risk factors for posttraumatic seizures. this prospective study was performed in a series of 470 head injured patient from January 1996 to Decomber 1998. The patients who were dead within 1 week of injury or children from 3 years old and under were excluded. There were 358 male and 112 female with a mean age of 35.2±22.8 years (range, 4-88 years). The results were as follows : 1). Of the 470 patients, pasttraumatic seizure occurred in 48 patients(10.2%): early seizure in 28(6%) and late seizure in 20 patients(4.2%). 2). The clinical risk factors for posttraumatic seizure were poor consciousness at admission, presence of brainstem herniation signs, poor GCS score, and posttraumatic amnesia more than 24 hours after trauma(p<0.001). 3). The radiological risk factors for posttraumatic seizure were subdural hematoma(p<0.001), intracerebral hematoma (p<0.02), mutiple intracranial CT lesions(p<0.001), or delayed lesions on follow-up CT scans(p<0.001). the incidence of seizure increased according to the severity of diffuse brain lesion(p<0.001), and the seizure rate in mass lesion was higher than that in diffuse lesion(p<0.001). 5). Hypoxia and coagulopathy had a statistically significant influence on posttraumatic seizure(p<0.05). Hypoxia had a infuence on occurrence of late seizure(p<0.05). 6). The incidence of posttraumatic seizure signiticantly increased in surgical group compared with coservative group(p<0.001) and significantly increased in patient who underwent decompressive craniectomy compared with those who underwent craniotomy(p<0.001) 7). Preventive administration of antiepileptic drugs decreased the incidence of early seizure, but did not affect on the reduction of late seizure. 8). Multivariate logistic regression analysis showed the subdural hematoma, GCS score, delayed lesion, and intracerebral hematoma in order of importance for seizure risk. in conclusion, the risk factors affecting on the occurrence of seizure were clinical status at admission, CT lesions, and severity of diffuse brain inJury. Considering that hypoxia affected on the late seizure, it is necessary to detect and treat it immediately after trauma. In addition, the patients who underwent decompressive craniectomy should be carefully followed to evaluate the risk of late seizure. Even though preventive administration of antiepileptic drugs had a tendency to decrease the incidence of early seizure, it is unclear whether administration of antiepileptic drugs can reduce the incidence of posttraumatic seizures. Prospective study will be needed in the selected patients.

동진강의 식물상과 식생

이경보,김창환,이덕배,김종구,박찬원 한국환경농학회 2004 한국환경농학회지 Vol.23 No.1

동진강 일대의 인위적인 교란에 의한 하천식생의 복원 및 복구를 위한 기초적인 자료를 제공하고자 2001년 6월부터 2002년 3월까지 하천식생의 종 구성, 하천형태에 따른 군락의 구조, 현존식생의 분포 등을 종합적으로 분석한 결과는 다음과 같다.동진강 유역에서 조사된 하천식생은 73과 188속 238종 33변종 1품종으로 총 272종류가 조사되었다. 또한 관속식물의 생활형에 따라 분류하면 침수식물이 23종, 부엽식물이 7종, 부유식물이 2종, 정수식물이 18종, 습생식물이 53종, 수변식물이 168종이었으며, 수생식물과 습생식물은 각각 50종과 53종류로 전체 조사된 272종류 중 37.9%를 차지하였다. 식물생활형의 분포비율은 휴면형 1년생 식물이 97종 35.7%, 수생식물이 78종 28.7%, 반지중식물이 41종 15.1%, 지중식물이 22종 8.1%, 지표식물이 12종 4.4%가 관찰되었다.동진강 상류유역의 식물군락은 검정말군락, 검정말-실말군락, 붕어마름군락, 달뿌리풀군락, 고마리군락, 큰황새냉이군락, 여뀌군락 등 총 8개의 식물군락이 분포하였다. 동진강 중류유역은 수생식물인 줄과 갈대군락, 그리고 수변식물군락으로 고마리군락, 교란지식생인 환삼덩굴군락 등 총4개 군락이 분포하였고, 동진강 하류 유역은 자라풀군락, 붕어마름군락, 마름군락, 줄군락, 갈대군락의 5개 습생식물군락과 털물참새피군락, 고마리군락의 2개 습생식물군락, 새콩 등의 나대지 식물군락 등 총 8개 식물군락이 관찰되었다 This study was conducted to get some vegetation information and to find out a way to conserve the ecosystem in the Dongjin River. The riparian vegetation was investigted by Zurich-Montpellier school's method from June 2001 to March 2002. The number of riparian plants were 73 families, 188 genera, 238 species, 33 varietles or 272 Taxa in Dongjin River. The characteristics of life form spectra were 97 therophytes(35.7%), 78 hydrophytes (28.7%), 41 hemicryptophytes (15.1%) 22 geophytes (8.1%), and 12 chamaephytes (4.4%). The riparian vegetaton was identified 8 plant communities (Potamogeton brechtoldii, Hydrill verticillata, Ceratophyllum demersum, Potamogeton malaianus, Phragnites japonica, Persicaria thunbergii, Cardamine scutata, Persicaria hydropiper) in upstream, 4 plant communities(Zizania latifoliar, Phragmites communis, Persicaria thunbergii, Hunmulus japonicus) in midstream and 8 plant communities(Hydrocharis dubia, Ceratophyllum demersum, Trapa japonica, Zizania Iatifolia, Paspalum distichum, Phragmites communis, Persicaria thunbergii, Amphicarpaea edgeworthii) in downstream of the Dongjin River.

p-Anisaldehyde가 조골세포 분화에 미치는 영향

김경민 ․ 이도원 ․ 김현준 ․ 김아랑 ․ 장원구 대구대학교 산업기술연구소 2018 産業技術硏究 Vol.29 No.2

p-Anisaldehyde is a natural fragrance extracted from Pimpinella anisum L., and used as a preservative. This study examined the effect of p-anisaldehyde on osteoblast differentiation. First, cytotoxicity tests were carried out after examining the concentrations that did not show toxicity to the cells. The expression of osteoblast differentiation marker gene was confirmed by RT-PCR and was not effective in the treatment with p-anisaldehyde alone. However, p-anisaldehyde decreased the expression levels of inhibitor of differentiation-1 (Id1), distalless related homeobox (Dlx5), and runt-related transcription factor 2 (Runx2), which are osteogenic differentiation marker genes, which are increased in osteogenic condition. alkaline phosphatase (ALP) activity was also confirmed by ALP staining that p-anisaldehyde reduced ALP activity. These results show that p-anisaldehyde is effective in reducing osteoblast differentiation.

Tabu 탐색법을 이용한 PI 제어기 설계

원태현,황기현,문경준,이용길 동의공업대학 2000 論文集 Vol.26 No.1

We propose an adaptive Tabu search method changing neighbor solution's range to be searched each iteration according to an objective function and design a PI controller using the proposed Tabu search. We apply it to a time-delay system to evaluate the usefulness of the proposed method. overshoot, rising time, and settling time.

만경강 상류 수질 및 식생분포와 토양환경에 따른 하천식생의 종 다양성

이경보,김창환,이덕배,김종구,박찬원,나승용 한국환경농학회 2003 한국환경농학회지 Vol.22 No.2

만경강 상류유역 수질 및 하천식생 군락 변화를 조사 분석하여 수질에 따른 하천식생의 종 다양성 및 토양요인에 따른 종 다양성의 변화를 평가하기 위하여 2001년 6월부터 2002년 9월까지 만경강 상류유역 5개 조사지점을 선정한 후 조사를 실시하였다. 수질중 T-N의 농도는 전주천과 삼천에서 높았으며, 겨울철에 전주천에서 7.45 mg/L로 가장 높았다. 무기태 질소 성분벽 함량은 NH₄-N 경우 고산천과 소양천 유역은 0.01~0.06 mg/L 범위로 계절별 커다란 차이가 없는 낮은 농도를 나타냈으나, 생활하수가 유입되는 전주천과 삼천에서는 0.77~3.01 mg/L로 계절별로 큰 차이를 보였다. T-P의 농도는 계절별로 비슷하였으나 전주천에서 겨울천에 0.89 mg/L로 가장 높았다. 계절별 BOD의 농도는 고산천과 소양천 유역에서 0.92~2.14 mg/L를 나타내었으나 생활하수가 유입되는 유역에서는 2.01~7.65 mg/L범위를 보였다. SO₄²^(-)의 농도는 농업용수 수질기준인 50 mg/L를 초과하는 지역은 없었으며 소양천에서 다소 높았다. 만경강 지류인 고산천에서 조사된 식물은 59과 과 129속 165종 20변종으로 총 185종류가 조사되었으며, 소양천에서 조사된 식물은 53과 111속 141종 19변종으로 총 160종이었고, 전주천 하류에서 조사된 식물은 37과 68속 86종 15변종으로 총 103종이었다. 그리고 삼천에서 조사된 식물은 32과 92속 110종 18변종으로 총 128종류 조사되었으며, 만경강 본류인 하리유역에서 조사된 식물은 73과 134속 218종 33변종으로 총 251종류가 조사되었는데 식물의 생활형에 따라 분류하면 침수식물이 13종, 부엽식물이 5종, 부유식물이 2종, 추수식물이 26종, 수생식물이 46종, 습생식물이 47종으로 조사지점중 이 지역의 식생이 가장 다양하였다. 식물사회학적 방법에 따라 분류된 하천식생의 식물군락은 10개의 수생식물 군락과 2개의 습생 및 수변식물 군락으로 대별되어졌다. 이들 군락들에 대한 4종류(종수, 종의 풍부도지수, 종의 이질성지수, 종의 균등도지수)의 종 다양성과 토양요인(pH, EC, 유기물 함량, 전질소, 인삭)과의 관계를 분석한 결과 pH가 높을수록 4종류의 종 다양성 지수는 높아 졌으며, EC는 값이 높을수록 종수(SN), 종의 풍부도지수(SR), 종의 이질성지수(H'), 종의 균등도지수(J')가 낮아 졌다. 또한 유기물 함량(OM)과 전질소(T-N)의 경우도 4종류의 다양성지수와는 부의 상관관계를 나타내었다. 인산(P₂O_(5))은 4종류의 다양성 지수의 변화에 영향을 미치지 않았다. This study was conducted to evaluate influence of chemical properties in the riparian on the species diversity and to get plant information for enhancement of natural purification in Mankyeong River. The concentration of total nitrogen was high in Jeonju and Sam stream, while that of total nitrogen showed the highest peak in Winter. Concentrations of NH₄-N was 0.01-0.06 ㎎/L in Gosan and Soyang stream. The water quality of upstream along with Mankyeong River was suitable for the imgation source. The riparian vegetation was investigated by Zurich-Montpellier school's method from June, 2001 to September, 2002. The number of riparian plants were 59 families, 129 genera, 165 species, 20 varieties in Gosancheon, on the while 53 families, 111 genera, 141 species, 19 varieties in Soyangcheon The number of riparian plants in Hari basin was higher than that of other sites namely, 73 families, 134 genera, 218 species, 33 varieties. Riparian vegetation was consisted of 12 plant communities. The contents of organic matter, total nitrogen and electrical conductivity had negative relationship with species diversity (Species richness index, Heterogeneity index, Species evenness index, Species number). On the while, species diversity had positive relationship with soil pH. Species diversity of the plant communities were affected by topography and disturbance.

超硬 切斷工具 刃先의 應力分布 解析에 관한 硏究 (I)

李允景,金元鎰 慶南大學校 附設 工業技術硏究所 1987 硏究論文集 Vol.5 No.-

旋削에 의한 超硬 切斷工具의 傾斜面 應力 變形率 分布에 대한 靜剛性 解析을 한 結果 다음과 같은 結論을 얻었다. 切斷加工에서 切削깊이 方向의 切削速度 變化는 切削力에 큰 영향을 주지 않으며, 切削條件에 의한 應力, 變形率 變化는 移送이 클수록 크고 接觸길이 0.3㎜ 정도에서 應力 값이 크게 減少하므로 칩핑 가능성이 높다. 應力 및 變形率의 變化幅이 큰 것은 切削에 있어서 摩擦의 狀態가 칩 傾斜面 接觸길이 部分에서 一定하지 않는다는 것을 알았다. In the turning, Analyses of the static deformation relating to the destributions of stress and strain on a rake face of cemented carbide parting tool have obtained results which are as follows, 1. In the parting work, the change of cutting speed relating to cutting depth and direction has been greatly uneffected cutting force. 2. As feed grows larger, the change of stress and strain under cutting conditions grows larger, and the value of stress decreases greatly in the near contect length of 0.3㎜. therefore, It is highly possible thet chipping occurs. 3. In the cutting, the changed value of strain and stress which is large have been not uniformed the state of friction in the near contect length of Chip-rake face.