석면함유 슬레이트 지붕 물받이 퇴적물 중 석면 섬유 함유율

임지현,한솔민,김현석,신유민,박시은,허정윤,김민영,장봉기 순천향대학교 기초과학연구소 2022 순천향자연과학연구 논문집 Vol.28 No.1,2

This study attempted to determine the degree of asbestos release from the aging slate roof by comparing the asbestos content in the slate roof rain gutter with a colored steel plate (tin plate) over the slate roof. Four slate roof houses located in Haengmok-ri, Asan-si, Chungcheongnam-do, and one house constructed with a colored steel plate on the slate roof were selected to collect the sediment of the roof rain gutter. The asbestos fiber content was calculated by a point counting method using a polarization microscope after pretreatment with conversion treatment and hydrochloric acid treatment. The average asbestos content of the four slate roof rain gutter were 1.89%. However, asbestos was not detected in the Slate covering roof rain gutter, which were constructed on the slate roof. Asbestos fiber content was the highest at 2.89% in the slate roof rain gutter installed in 1976, followed by 2.44% in 1953. From the above results, it is necessary to minimize secondary damage as asbestos fibers released from slate roof houses to the surrounding atmosphere or leaked from slate roofs as rainwater may cause soil pollution and seriously affect residents' health. Although covering with colored steel plates (tin plates) has been shown to prevent the leakage of asbestos fibers to some extent, it is believed that a policy alternative to remove the slate roof as soon as possible is needed to solve the fundamental problem.

보리순의 영양성분 조성

서혜지,최용민,김상천,이준수,이기택,정명근,천지연,황진봉,남진식,서우덕,황영,김행란,김세나 忠北大學校 農業科學硏究所 2015 農業科學硏究 Vol.31 No.2

분말충진방법과 가공정도에 따른 Ag/BSCCO 초전도선재의 특성

지봉기,김태우,김정호,김중석,주진호 成均館大學校 科學技術硏究所 1998 論文集 Vol.49 No.1

We evaluated the effects of processing variables on interface irregularity. microstructure. and resultant Jc of BSCCC superconductor tape. For the tapes made by PIT technique. the degree of interface irregularity was varied with powder packing methods and forming process variables. It was observed that the degree of interface irregularity of the tape by CIP method was more reduced. compared to that of the tape by ram method. In addition. the degree of interface irregularity was promoted with decreasing the dimension of tape during forming process. As the dimension of wire/tape were changed from diameter of 3.25mm to thickness of 200㎛ during forming process. Jc value was observed to be increased by 10 times. It was likely that the improvenment of Jc was mainly result from the enhanced texturing of 2223 grain. Microstructural investigation showed the degree of texturing was degraded by the existence of both second phases and interface irregularity. If the interface was flat, larger grain size and better texturing near interface were developed compared to those inside superconducting core, The improvements of microstructure near interface may be result of reaction between Ag and superconductor phase.

뇌수술 시 과호흡과 만니톨의 투여가 뇌혈류와 뇌산소대사에 미치는 영향

김지헌,김경식,문봉기,조경기,신용삼,이영주,김진수 대한마취과학회 2002 Korean Journal of Anesthesiology Vol.43 No.4

Background: There are therapies to lower intracranial pressure (ICP) including head elevation, hyperventilation, diuretics injection, intravenous mannitol, hypothermia, cerebrospinal fluid drainage, and cerebral resection in neurosurgical patients. However in recent reports, hyperventilation followed by mannitol administration may lead to cerebral ischemia. Therefore, we investigated the effect of 0.5-1.0 g/kg mannitol administration on jugular venous oxygen saturation (SjVO_2) and cerebral arterial-jugular venous oxygen content difference (AVDO_2) at PaCO_2 25-30 mmHg and 35-40 mmHg in patients undergoing neurosurgery. Methods: we studied 17 patients undergoing neurosurgery in the Ajou University Hospital. Anesthesia was induced with fentanyl, midazolam, thiopental, and vecuronium, and maintained with )_2-Air-Isoflorane, a continuous infusion of fentanyl, and vecuronium. Patients were divided into two groups. Group 1 (n = 10) which is PaCO_2 25-30 mmHg and Group 2 (n = 7) which is PaCO_2 35-40 mmHg by controlling ventilator. Measurements of SjVO_2 and AVDO_2 in following time intervals: Ⅰ = preinjection of mannitol, Ⅱ = postinjection 20 minutes of mannitol, Ⅲ = postinjection 40 minutes of mannitol were obtainde for each group. 0.5-1.0 g/kg mannitol was administered intravenously just at duramater opening. Results: Hemodynamics and hematologics were not significantly different among the two groups. SjVO_2 of each group are as follows; Group 1; Ⅰ (70.3 ± 8.1%), Ⅱ (66.3 ± 6.9%), Ⅲ (69.1 ± 7.9%) and Group 2; Ⅰ (78.6 ± 7.4%), Ⅱ (75.1 ± 8.1%), Ⅲ (76.0 ± 11.2%), Hyperventilation significantly decreased SjVO_2- AVDO_2 was not significantly different but SjVO_2 in Ⅱ was significantly decreased compared with Ⅰ and Ⅲ in Group 1 (20% patients). Conclusions: Mannitol produced a change of SjVO_2 during hyterventilation. Therefore, intravenous mannitol during hyperventilation should be given cautiously according to the patients status because it may cause cerebral ischemia in critical patients. (Korean J Anesthediol 2002; 43: 462~467)

건축물 고형시료 중 석면 분석을 위한 방해 물질 제거방법에 대한 연구

김윤재,임지현,장봉기 순천향대학교 기초과학연구소 2021 순천향자연과학연구 논문집 Vol.27 No.1.2

In this study the following pretreatment methods are proposed using solid samples of buildings : furnace ashing methods according to the existing waste process, acid treatment after furnace ashing, acid treatment using graphite block acid circulation, a new method of attempting. This study propose a method for pretreatment of solid samples in buildings containing asbestos with a comparison of the asbestos analysis obstruction removal rates according to the above mentioned methods. The materials used in this study are 48 slates of 3 types and 48 textures of 3 types, total 96 samples which are solid samples in buildings. Pretreatment and acid treatment methods were classified in four ways: Electric high temperature furnace ashing methods according to the existing waste process and acid treatment with HCl(1+3)(Group A), Electric high temperature furnace ashing methods and acid treatment with aqua regia(HCl 3 : HNO3 1)(Group B), acid treatment with aqua regia(Group C) using graphite block acid circulation, a new method of attempting and acid treatment with inverse aqua regia(Group D). The removal rate of furnace ashing from slate samples in A and B treatment groups was 13.91%, and the removal rate of furnace ashing from texture samples in A and B treatment groups was 9.21%, so the removal rate of furnace ashing from slate samples was significantly higher than texture samples(p<0.001). The removal rate of asbestos analysis interfering substances from slate samples and texture samples in C treatment group with acid treatment with aqua regia using graphite block acid circulation were 30.50% and 30.58%, respectively. So in both slates and texture samples, the removal rate of asbestos analysis interfering substances from the slates and texture samples of A, B, and D treatment groups was significantly higher(p<0.001). The newly proposed acid treatment with aqua regia using graphite block acid circulation method in this study significantly eliminated more acid solubility material and asbestos analysis interfering substances than electric high temperature furnace ashing methods according to the existing waste process and acid treatment with HCl(1+3), and this method does not go through the process with high temperature furnace ashing, it is believed that asbestos analysis can be made easier by preventing changes in the characteristics of asbestos and the use of graphite block acid collection devices when acid treatment of solid samples in buildings containing large amounts of asbestos analysis interfering substances can be more effective than conventional methods.

섬유강화형 포스트를 이용한 치관-치근 파절의 치료: 증례 보고

임화신,라지영,이광희,안소연,김윤희,금기석,이상봉 大韓小兒齒科學會 2012 大韓小兒齒科學會誌 Vol.39 No.1

The crown-root fracture is defined as a fracture of tooth that contains enamel, dentin and cementum with or without pulp exposure. Generally the fracture lines place obliquely from labial surface, between incisal edge of the crown and marginal gingiva, to palatal surface subgingivally. If the fracture line is located supragingivally, the removal of tooth fragment and supragingival restoration can be performed. In subgingival fracture line, the surgical exposure, orthodontic eruption or surgical eruption can be considered. If the fracture line is too deep to restorate, extraction or decoronation can be selected. In children and adolescents, the extraction should be the last option. Another option to select before extraction is the restoration using fiber-reinforced post and the reattachment of tooth fragment. The fiber-rainforced post enhances the retention and the durability of tooth fragment. The reattachment of crown fragment using resin adhesive system is considered minimal invasive treatment biologically. This case reports the treatment of crown-root fracture using the reattachment of crown fragment and the insertion of fiber-reinforced post. 치관-치근 파절은 법랑질, 상아질, 백악질이 모두 포함된 치아의 파절로, 파절선이 대부분 절단연이나 순측의 변연부 치은 에서 구개측 치은열구 하방으로 사선으로 진행된다. 파절선의 위치가 치은 연상이라면 파절편의 제거 및 치은연상 수복을 시 행하고, 치은 연하라면 파절면의 외과적 노출술, 교정적 정출술, 외과적 정출술을 이용한 치아의 수복이 이루어진다. 그 외에 섬유 강화형 포스트를 삽입하여 치관 수복물의 유지력을 높이고, 레진 접착 시스템을 사용하여 치관 파절편을 재부착함으로 써 생물학적으로 최소한으로 침습적인 치료를 하는 방법도 있다. 만약 파절의 정도가 치은 연하로 깊은 경우 발치나 치관절제 술을 이용한 치근의 유지 등을 고려할 수 있다. 본 증례는 치관-치근파절로 내원한 12세 환아로 섬유강화형 포스트를 사용하여 치관 파절편 재부착을 시행하였으며 양호 한 경과를 보여 이를 보고하는 바이다.

水産專門大學 漁業科 敎育課程 開發硏究

裵錫悌,宋之浩,李吉來,鄭興基,洪聖根,趙鳳坤,朴種洙 군산대학교 1983 群山水産專門大學 硏究報告 Vol.17 No.1

In order to develop the curriculum of the fishery department in the fisheries Jr. college, We have collected and analyzed the domistic and foreign data adquated to the fishey department under the international trend, also we gathered the opinion from the inquiring paper investigation and consultation to the industrial field, concerned college and graduate during the 6 month from September 1982. The fishery department curriculum in fisheries Jr. college will be industrialized with the concerned technics and knowledge in relation to speciality of maritime affairs. Accordingly, we have developed the adquate curriculum which is practical and can be cultivated the technician to adopt in the industrial society.

鮟鱇網 漁具 漁法의 改良에 관한 硏究(Ⅱ) : 展開帆을 이용한 改良漁具 試驗(豫報)

李吉來,宋之浩,朴鍾洙,徐萬錫,趙鳳坤,朴正鎬,洪聖根,鄭公炘,裵錫悌,鄭與基,金鎭乾 군산대학교 1980 群山水産專門大學 硏究報告 Vol.14 No.1

Ordinarily stow net fisheries was used by floater beam and sinker beam for the purpose of spreading the mouth of net. But it was not only iuconvenient and dangerous but much defective. In this thesis, we have studied fundermental experiment of the improved stow net fishing gear using head rope, ground rope and otter sail instead of floater beam and sinker beam. From the result of this experiment, it has been succeeded for fishing work to achieve basically without any difficulty. The results obtained in this study were as follows. 1) The resistance of fishing gear was estimated R≒7V2 as possible as it is taken greatly. (R: Resistance V: the rate of current) 2) The interval of otter sail was spreaded smoothly. Being in normal condition, it was maintamed the width 37-38m. It was heared comparison with net mouth of ordinary gear, and the shearing force was enough. 3) The height of mouth was lower than we have anticipated to and seemed to have the supplement of buoyancy. But according to increasing the rate of current, the lowness of mouth height was little affected. 4) The height of otter sail was decreased at the rate of 30% by the rate of current, on the contrary, the height of wing was not decreased owing to sufficient buoyancy, 5) The adjustment of extention length of hanging wire(connected with fishing boat) and raising wire(with otter sail) was great important problem and it must be dealed with the most moderatly because of a corelation between the spreading of fishing gear and catching ability. 6) On the depth of 30m, it was taken 25 minuits to cast anchor and lines, 20 min cast net, 24 min haul net, 45 min haul lines and heave anchor, respectively. 7) The improved stow net with otter sail was cleared up the defects and difficult problems in ordinary gear using floater beam and sinker beam, and it have more advantages of fishing work than ordinary one. But there were involved in lots of problems in details to solve in the future.

일차성 PTCA시 발생한 좌신 및 총장골 동맥으로의 코일형 스텐트 전이 경험 1예

유병수,윤정한,이봉기,고지연,이승환,황성오,최경훈 대한순환기학회 1999 Korean Circulation Journal Vol.29 No.11

쪽거리 차원을 통한 다공질규소의 미세구조 분석

김영유,홍사용,이춘우,류지욱,이기환,최봉수 대전산업대학교 반도체기술연구소 1999 半導體技術硏究所報 Vol.1 No.-

p형 단결정 규소 웨이퍼를 불화수소 용액속에서 전류밀도와 양극반응 시간을 변화시켜 다공질규소를 제작하고, 그 질량을 측정한 후 이 값으로부터 다공도와 쪽거리(fractal)차원을 계산하였다. 그 결과 양극반응 시간이 일정한 경우 다공도는 전류밀도에 비례하였다. 그리고 전류밀도가 일정한 경우 여러 양극반응 시간의 데이터로부터 얻은 쪽거리 차원은 일정하였다. 또한 쪽거리 차원은 불화수소의 농도 증가에 따라 감소하였다. 이같은 실험 결과를 퍼짐한계침전(diffusion limited deposition) 모형으로 계산된 2차원 컴퓨터 시늉내기(simulation) 결과와 비교 분석하였다. 시늉내기 결과 다공도는 퍼짐거리에 비례하였으며, 쪽거리 차원은 퍼짐거리와 반비례하였다. 이때 퍼짐거리는 전류밀도에 비례하고 불화수소의 농도에 반비례하는 물리량이므로 정성적으로 실험 결과와 일치하였다. 그러나 쪽거리 차원이 증가함에 따라 다공도가 감소되는 결과는 실험결과와 상반되었다. Porous silicon layers were fabricated with various conditions of HF concentration and current density. And their masses were measured. From these data, the porosity and fractal dimension were estimated and analyzed. We found that the porosity was proportional to the current density when the anodic reaction time was fixed and the constant values of fractal dimension could be estimated from a series of data with fixed HF concentration. The values of fractal dimension were decreased with increasing HF concentration. The obtained porosity and fractal dimension were compared with the 2-dimensional computer simulation based on diffusion limited deposition model. According to the simulation, the porosity was proportional to the diffusion length and the fractal dimension was inversely proportional to the diffusion length. Since, the diffusion length is proportional to current density and inversely proportional to base concentration, our experimental data qualitatively agreed with the results from the simulation. The porosity obtained by experiments, however, was not consistent with the results by simulation.