치주조직 재생을 위한 칼슘 포스페이트 글라스가 MC3T3-E1 세포의 증식, 분화 및 석회화에 미치는 영향

이용근,송진,이상배,김경남,최성호 大韓齒科器材學會 2003 대한치과재료학회지 Vol.30 No.2

The purpose of this work was to exploring the influence of the prepared calcium phosphate glass on the proliferation, differentiation, and mineralization of the culture system of the pre-osteoblastic MC3T3-E1 cells. Polystytene was employed as a control in this experiment. Cells were cultured in a differentiated medium onto the calcium phosphate glass as well as polystyrene, and the number of cells and the protein contents were determined. To examine osteoblast differentiation, the alkaline phosphatase activity was measured. Mineralization was evaluated by staining the calcium deposit with Alizarin red. Culture onto the calcium phosphate glass exhibited no significant difference in cell proliferation compared with control group. The alkaline phosphatase activity in the experimental group, however. was enhanced In the calcium phosphate glass significantly at 10-18 days than that of the control group (p<0.05). Enhancement of bone-like tissue formation by the addition of the calcium phosphate glass was observed since 7 days. The results of the present study indicate that the prepared calcium phosphate glass promotes osteogenesis by increasing collagen synthesis and calcification of the extracellular matrix. It maybe due to greater calcium concentration in the culture medium released from the calcium phosphate glass.

세라믹스의 치과응용

이용근,김경남 대한치과기재학회 1999 대한치과재료학회지 Vol.26 No.4

풍동실험을 위한 LabVIEW 응용 온라인 계측시스템의 개발

김봉근,장성태,이경용,박운진 한국기술교육대학교 2004 論文集 Vol.10 No.2

On-line measurement systems were newly developed for the performing effective wind tunnel experiments by utilizing the LabVIEW(Laboratory Virtual Instruments Engineering Workbench) system. As a result, instead of post-data-processing procedures based on Fortran programming which was commonly adopted in conventional measurement systems, wind tunnel experiments can be carried out on window-based PC operating systems and thus much time and effort required in analyzing fluid flow field can be successfully reduced. Furthermore, by utilizing the web publishing tool which is provided by the LabVIEW, it is possible to monitor and to control each measurement step via internet web pages from the remote area other than the laboratory in which experiments are carried out.

치과용 도재분말의 제조 및 물리적 성질

염근창,고대진,장감용,이서영,김경남 大韓齒科器材學會 1994 대한치과재료학회지 Vol.21 No.1

In this study, the prepared glasses were heat-treated to precipitate the leucite crystal in order to control the thermal expansion coefficient which is an important property of dental porcelain powder. The effect of addition of Li₂O and Na₂O on the amount of the precipitated leucite crystal were also examined. The mixing ratio of the leucite-containing glass must be controlled to match the thermal expansion coefficient of dental porcelain to that of metal. The physical properties of the dental porcelain powder prepared in this study were characterized. The results of this study were obtained as follows : 1. Conditions for the preparation of the maximum amount of leuctie crystal were compostion L-2(2.0 wt% Li₂O added) heat-treated at 950℃. 2. The phase of the precipitated crystals was turned out to be the tetragonal leucite crystal. 3. Maximum relative crystallinity was 64.2% for composition L-2, heat-treated at 950℃. Its linear thermal expansion coefficient was 16.1×10-6/℃ in the range of room temperature to 500℃. 4. The optimum mixing ratio of the leucite-containing glass was 45% in order to match the thermal expansion coefficient of dental porcelain to that of metal. In this case, the thermal expansion coefficient of the prepared dental porcelain was 10.6×10-6/℃ (∼500℃). 5. The physical and chemical properties of the prepared dental porcelain were suitable for the requirements of ISO 6872 and 9693.

전방 또는 전측방 흉수 종양 수술에서 후측방도달법

조경석,박춘근,성재훈,허필우,박춘근,백민우,김달수,강준기 대한신경외과학회 1997 Journal of Korean neurosurgical society Vol.26 No.5

치과 급속 교정용 초내식성 스테인리스강 가공재의 특성

오근택,김영식,김경남 대한금속재료학회 2004 대한금속·재료학회지 Vol.42 No.1

When stainless steels are used in the human body, the nickel ion released from the alloys over a short or long term can cause such adverse effects as allergies, dermatitis, asthma. Although the higher the corrosion resistance of stainless steels and the lower the nickel content, the better it is for the human body, since nickel has an essential role in the stabilization of the austenitic phase and the corrosion resistance of stainless steels, it is difficult to remove nickel completely. In this regard, the purpose of this study was to investigate corrosion resistance, cytotoxicity and mechanical properties of super stainless steels, and upon this basis, to evaluate their potential for orthodontic applications. Super austenitic stainless steels had higher content of nickel(17~20 wt%) than super duplex stainless steels (7~10 wt%) or super ferritic stainless steels (lower than 3 wt%). Super austenitic and duplex stainless steels had nitrogen content of above 0.2 w%. These steels had high Mo or W contents of which synergistic effect together with N increases localized corrosion resistance. In terms of hardness, super stainless steels exhibited higher value than 316L S. S. and two times higher than cp Ti(grade II). Austenitic and duplex stainless steels exhibited better mechanical properties. Super stainless steels exhibited low passive current density (3~4 μA/㎠) and similar potentiodynamic polarization behaviors among themselves. Thus, these steels are considered to have high corrosion resistance in the human body-simulated solution. Pitting corrosion occurred in 316L S. S.. A3 containing the highest nickel content, as well as SAF2507 exhibited none cytotoxicity, and the others, slightly. This indicates that the cytotoxicity has no direct relation with nickel content itself in these alloys. Super stainless steels with both high corrosion resistance and good biocompatibility are expected to be used for orthodontic applications by virtue of the passive film attribute enhanced by synergistic effect of Mo+N or by high addition effect of Cr+W.

신경망을 이용한 공정 오차 보정

전경아,유지용,오혜근 한양대학교 이학기술연구소 2002 이학기술연구지 Vol.5 No.-

패턴의 미세화에 따른 정확하고 신속한 결과 예측은 Iithography simulation tool 의 높은 공정 변수 의존을 요구한다. 이로 인해 simulation tool 은 공정 변수 사이의 보정이 더욱 복잡해져 광 근접 효과 등으로 나타나는 다양한 패턴들의 크기 결과를 예측하는데 많은 어려움을 겪게된다. 이에 본 논문에서는 simulation 결과 값과 실측값의 차이를 신경망 알고리즘에 적용하여 공정 변수를 최적함으로서 simulation tool의 예측 정확성을 향상시키는 방법을 제시하였다. It is required to make an accurate and quick prediction of critical dimension (CD)for higher integrated devices. Because simulation tools consist of many process parameters and models, it is difficult that process parameters are calibrated to match the CD results for various patterns. This paper presents a method of improving the accuracy of predicting CD results by applying △ (the difference between simulation and experimental data) value to neural network algorithm (NNA) in order to reduce the CD difference caused by optical proximity effects.

교정용 스테인리스강 선재의 내식성에 미치는 응력 제거 열처리 조건의 영향

오근택,전용석,황충주,김경남 대한치과기재학회 2001 대한치과재료학회지 Vol.28 No.2

Heat treatment is applied to orthodontic wires in order to relieve the stress that results from cold working and the orthodontists manipulations. In this study, 4 types of wires were heat-treated in an air, argon or vacuum environment, and were either cooled in a furnace or a water bath. Corrosion properties of the heat-treated wires were investigated by potentiodynamic method. The difference of corrosion resistance between the wires heat-treated in an ambient according to cooling methods was not significant. After heat-treated in an ambient, both water-cooled and furnace-cooled wires had a similar and low corrosion resistance. The difference of corrosion resistance between the wires heat-treated n a vacuum environment with cooling methods was significant. After heat-treated in a vacuum, the furnace-cooled wires had high corrosion resistance, but the water-cooled wires low. After heat-treated in a vacuum, argon, or air environments, the water-cooled wires had low corrosion resistance. It was considered because the irregular and unstable film was formed on the surface of the wires when cooled in a water bath. The control wires showed a low current density and high pitting potential, but most of the heat-treated wires did high current density and low pitting potential except for the wire heat-treated in vacuum and then cooled in a furnace. Conclusively, orthodontic wires are considered to have to be heat treated in vacuum condition or inert gas environment and then to be cooled in a furnace in order to inhibit surface oxidation, minimize the decrease of corrosion resistance and improve the mechanical properties.

폐탄광 배수에 의한 주변 화천 오염 실태 조사

조경숙,장용근,류희욱 崇實大學校 生産技術硏究所 1996 論文集 Vol.26 No.1

The survey was carried out to investigated the contamination of streams by the acid mine drainage originates from abandoned coal mines and coal refuse piles. The physico-chemical characteristics such as pH, sulfate and elements concentrations of waters and sediments in streams were analyzed, and the microbial activities in the sediments were evaluated by measuring dehydrogenase activities. In sites contaminated by the acid mine dranage, the pH of waters adn sediments declined to acid from neutral due to the accumulation of sulfate. Dehyfrogenase activities ranged from 12 to 170 ㎍-TPF·g-dry soil-¹·24h-¹in the contaminated sites, whereas teh uncontaminated sites had activities of 1,176-4,259 ㎍-TPF·g-dry soil-¹·24h-¹. Dehydrogenase activities were significantly affected by low pH of sediments, indicating that high strength of sulfate inhibited microbial activities. The concentrations of heavy matals such as Pb and Fe in contaminated sediment (37-46 ppm Pb; 46,000 ppm Fe) were much higher than those in the uncontamnated sediments. concentration of Al in the contaminated water acidfied by the abandoned coal drainage was in range of 11 to 42 ppm. compared with those in the uncontaminated sediments, the concentrations of Mn, Mg and Ca in contaminated sediments were low because of the leaching of them from soil to water by acidfied stream water.

신고리 지역 기상관측을 통한 계절별 대기안정도 특성분석

송상근,김유근,오인보,정주희,조윤미,우경은,강태훈 부산대학교 환경문제연구소 2003 環境硏究報 Vol.21 No.-

In this study, we analyzed the characteristics of atmospheric stability to investigate local environment change at an atomic power plant in Gori region. The used data was obtained from field observation of major meteorological variables such as wind direction and speed, air temperature, relative humidity, and solar radiation using AWS (Automatic Weather System) in Gori region from February to September in 2003. As a result, when strong northerly winds (more than 4~6 m/s) and weak northwesterly winds (2~3m/s) blow, atmospheric stability was neutral and stable from winter to spring, respectively. Atmospheric stability (neutral) in summer was similar to that in two other seasons (winter and spring), but it was stable for weak southwesterly winds (2~3 m/s). Finally, atmospheric stability was neutral for strong winds (over 4~6 m/s) in fall without respect to wind direction, while that was stable for very weak winds (less than 2 m/s).