Fluid transport model을 이용한 치근단 역충전 재료의 혈액오염시 미세누출평가

안효순,장인호,이세준,이광원 大韓齒科保存學會 2002 Restorative Dentistry & Endodontics Vol.27 No.1

Leakage studies have been performed frequently, since a fluid-tight seal provided by various dental filling materials has been considered clinically important. The leakage of the various root-end filling materials has been widely investigated mostly dye penetration method. These dye studies cannot offer any information about the quality of the seal of a test material over a long period of time The purpose of this study was to evaluate the microleakage of root end cavities in blood contamination filled amalgam, intermediate restorative material(IRM), light cured glass ionomer cement(GI) and mineral trioxide aggregate(MTA) by means of a modified fluid transport model. Fifty standard human root sections, each 5mm high and with a central pulp lumen of 3mm in diameter, were and filled with our commonly used or potential root end filling materials after they were contaminated with blood. At 24h, 72h, 1, 2, 4, 8, and 12 weeks after filling, leakage along these filling materials was determined under a low pressure of 10KPa(0.1atm) using a fluid transport model. The results were as follows: 1. MTA group showed a tendency of decreasing percent of gross leakage(20ml/day) in process of time, whereas the other materials showed a tendency of increasing in the process time. 2. At the all time interval. GI group leaked significantly less than amalgam group and IRM group (p<0.05). 3. At the 4 weeks, the percentage of gross leakage in MTA group decreased to 0% thereafter, the low percentage of gross leakage was maintained in MTA group until the end of the experiment, whereas the percentage in IRM group increased to 100%. 4. At the 12 weeks, percentage of gross leakage was significantly low in MTA group(0%), comparison with GI group(40%), amalgam group(90%) and IRM group(100%), but there was no significant difference between latter two materials.

隔壁의 傾斜에 따른 箱子桁의 硏究

鄭熺孝,安光列,李承烈,朴泳珏 경상대학교 생산기술연구소 2002 工學硏究院論文集 Vol.2 No.-

The box girder has became a popular bridge type for long span or curved bridges because of its structural advantage of torsional stiffness. Generally box girder have inner diaphragms. The purpose of diaphragms is to prevent the deformation of cross section shape. Most diaphragms are parallel to cross section but it is necessary at present to adapt the design of bridge structures to transport requirement and the restrictive conditions of environment. City bridges, bridges spanning railway lines and stations, skew crossing of streets and highways, etc., require an irregular arrangement of internal supports. If diaphragms are applied, they are usually skew. It is advantageous to use a box girder as the basic component for a bridge of this kind because the box girder provides a high torsional stiffness, a favorable stresses, and due to the small shear stresses arising due to torsion. This paper deal with the analysis of the function of irregularly situated support and skew diaphragms and with their influence on the resulting state of stress of the box girder and compare with vertical deflections, horizontal deflections, longitudinal stresses, distortional stresses according to the angle of diaphragms.

편심하중을 받는 상자형의 단면변형에 관한 연구

鄭熺孝,安光列,金鎬洙,黃俊碩 경상대학교 생산기술연구소 2001 工學硏究院論文集 Vol.1 No.-

Eccentric load acts on box girder is divided into bending and torsional load and deforms cross section. Distortion that is resulted from torsional load is largely different according to tickness of each plate or stiffener. According to with and without regard of distorsion effect, it is possible to divide analysis of box gilder into two. First, analysis of box gilder can be able to calcurate with rigid box girder in assumption that there is no distorsion when the girder is well stiffened with diaphragms or cross bracing and plate thickness of box section is thick. Second is the analysis that must be considered effect of distorsion when the girder has not sufficient stiffener or plate thickness of box section is not well thick. In numerical example of this study, normal stress of rigid cross section analysis is compared with that of deformable cross section analysis without interior diaphragms. Then, it was studied that stresses of the deformable cross section analysis can be near rigid analysis when box girder was stiffened with interior diaphragms.

중간스프링을 가진 개선된 탄성지반상(彈性地盤上) 보의 휨해석

鄭熺孝,李承烈,安光列 慶尙大學校 經營行政大學院 2004 工學硏究院論文集 Vol.20 No.-

While the BEF(Beam on Elastic Foundation, Wright et al, 1968) analogy has been widely used in straight and simple supported box girder analysis, the EBEF(Equivalent Beam on Elastic Foundation, Yao. T. Hsu et al, 1995) analogy has been made possible in curved and continuous box girder. Instead of using the traditional trigonometric foundation to solve a BEF problem, EBEF analogy used stiffness matrix considering bending, shear, elastic foundation and defined middle diaphragms in box girder as middle supports of continuous beam. In this study, for the comparison with BEF analogy, the element length of beam is determined first and infinity support stiffness corresponding to dimensionless middle diaphragm stiffness is determined in EBEF analogy. Two approaches, BEF and EBEF analogy are compared in the beam on elastic foundation.

거더의 單純化 解析에 관한 硏究

鄭熺孝,安光列 慶尙大學校生産技術硏究所 1999 生産技術硏究所論文集 Vol.15 No.-

A simplified method to analyze pin-ended girders under uniform load is presented. This method is shown to estimate the maximum moment, shear and deflection of the girder without calculating any of the beam reactions it supports. If exact solutions for the maximum moment, shear and deflection are needed, they can be easily found by multiplying the approximate results by a tabulated constant. Results are valid for any type of pin-ended girder, provided structures are made by uniformly spaced beams or trusses. This method can easily be programmed into a spreadsheet, calculated by hand or incorporated into an existing software package.

경사격벽을 가진 상자형의 해석

鄭熺孝,安光列,李承烈,朴泳珏 경상대학교 생산기술연구소 2001 工學硏究院論文集 Vol.1 No.-

It is necessary at present to adapt the design of bridge structures to transport requirement and the restrictive conditions of environment. City bridges, bridges spanning railway lines and stations, skew crossing of streets and highways, etc., require an irregular arrangement of internal supports. If diaphragms are applied, they are usually skew. It is advantageous to use a box girder as the basic component for a bridge of this kind because the box girder provides a high torsional stiffness, a favorable stresses, and due to the small shear stresses arising due to torsion. This paper deal with the analysis of the function of irregularly situated support and skew diaphragms and with their influence on the resulting state of stress of the box girder. The solution is shown for a box girder under eccentric load and according to the length of skew diaphragms.

개선된 탄성지반상 보의 휨해석

鄭熺孝,安光列,李承烈,朴泳珏 경상대학교 생산기술연구소 2002 工學硏究院論文集 Vol.2 No.-

The BEF(Beam on Elastic Foundation) analogy was first noted by Vlasov and then utilized for the distortional analysis of box girders by Wright et al., but it was limited only to prismatic straight box girders. With the development of this study, a more generalized element in a stiffness matrix form was presented. With this element, which is "equivalent" to the BEF(Beam on Elastic Foundation) analogy, more complicated configurations can be resulted. In this study, it compares analysis results using the traditional trigonometric function to solve a BEF(Beam on Elastic Foundation) problem with analysis results using stiffness matrix form to solve a EBEF(Equivalent Beam on Elastic Foundation).

Analysis of motor neural pathway using the expression of WGA in the spinal cord

Hyo Kwang Ahn,Junyang Jung,Youngbuhm Huh 대한체질인류학회 2016 대한체질인류학회 학술대회 연제 초록 Vol.59 No.-

Development of Colored Index of Teeth Due to the Korean Favorite Food Intake

Hyo-Kwang Ahn,Jung-Eun Park,Ji-Eun Kim,Ha-Jeong Kwon,Byung-Ryeul Lee,Chan-Ho Kim,Dae-Kyeong Kim,Wang-Gi Kim,Yong-Duk Park,Kyung-Sook Hwang 대한예방치과학회 2014 International Journal of Clinical Preventive Denti Vol.10 No.4

Objective: After selecting the food Korean favorite ingested repeatedly given time, evaluate the degree of coloration of the teeth, it is aimed to develop indices have scored the ranking by in vitro test. Methods: Hydroxyapatite discs (10×2.0 mm) were dipped each in ten food (all 19 species) and the food cause coloring of the teeth, the colored discs were measured by dental chroma meter (Shadeeyenccⓡ) at the control, 30, 60 120, 240, and 420 every minute, color was the basis of the vita shade guide procedure. The colored causative agent was replaced every 30 minutes. The degree of coloring (digitized into 0-100) was compared relatively. Change in the darkest color gave .100 points, and no change gave 0 points. Results: In this study, group colored relatively high were analyzed in the order of A (black tea), B (chocolate, [americano coffee]+chocolate, kimchistew, instant noodles), C (soy sauce, americano coffee), D (red ginseng, americano coffee+curry, caffe latte), E (red wine, black-bean-sauce, noodles, tomato sauce) and Z (curry, red pepper paste, tomato sauce+red wine, orange juice, kimchi, cola). Conclusion: Black tea commonly used in studies of whitening teeth greatly changes among the coloring changes. And in the group included green tea or coffee the most part, changes in the coloration of the teeth were greater. But, cola or juice were not related to the coloring. In order black tea, chocolate, kimchi, the color change was fast in a short period of time. But the americano changed quickly the color, after being colored cumulatively.

일식 레스토랑의 고객만족과 충성도에 대한 서비스 품질에 관한 연구

안효주(Hyo-ju Ahn),안광열(Kwang-yeol Ahn),신충섭(Chung-sub Shin) 한국컴퓨터정보학회 2004 韓國컴퓨터情報學會論文誌 Vol.9 No.2

The purpose of this research is to study the effect of service quality improvement strategy and its practices on firms' competitive advantage, and identify their influence on customer satisfaction and loyalty.<br/> According to this purpose, this paper hypothesized that high service quality will satisfy customers' needs and result in improved customers' loyalty. Thus, empirical study was conducted to identify the relationships among factors which were identified through literature review. Data were collected from the customers of 3 luxurious japanese restaurants in Seoul.<br/> The result of data analyses shows: (1) Serve quality factors such as customer service, quality of meal, location and facility, and types of restaurants make significant difference among three restaurants in terms of customers' perception about service quality: (2) There is statistically significant difference among three restaurants in terms of customers' satisfaction, but there is no significant difference among them in terms of customers' loyalty: and (3) Not only the result from analysis on japanese restaurants inside hotels but also that on the independent japanese restaurant in Kangnam area, shows that service quality factors have significant effect on both customers' satisfaction and loyalty.