상아질에 적용된 재 습윤제가 미세인장 결합강도에 미치는 영향

강희영,조영곤,김종욱,박병철,유상훈,진철희,최희영,기영재 大韓齒科保存學會 2004 Restorative Dentistry & Endodontics Vol.29 No.2

This study investigated that the effect of rewetting agent on dentinal microtensile bond strength (μTBS). Human molars were sectioned to expose the superficial dentin surfaces. Samples were divided into two groups according to type of adhesives-Single Bond (S) and One-Step (0)], and again subdivided into five groups by different dentin surface treatment-dry for 15s (D) , blot dry (BD) or dry for 15s, and rewet with different rewetting agents[distil1ed water (DW), Gluma Desensitizer (GD) and Aqua-Prep (AP)]for 30s. After application of adhesive, composite resin was built up on the bonding surface. Each tooth was sectioned to obtain stick with 1mm^(2) cross sectional area and the μTBS was determined by EZ test. In the S group, the mean μTBS of GD, AP and BD group was significantly higher than that of DW and D group (p < 0.05). In the 0 group, the mean μTBS of AP, GD, BD and DW group was significantly higher than that of D group (p < 0.05). The data suggested that Gluma Desensitizer and Aqua-Prep could be successfully used as rewetting agents, and Distilled water could be acceptable in aceton based adhesive system only.

자가 산부식 프라이머의 적용시간이 상아질의 미세인장 결합강도에 미치는 영향

조영곤,이영곤,김종욱,박병철,김종진,최희영,진철희,유상훈 大韓齒科保存學會 2004 Restorative Dentistry & Endodontics Vol.29 No.5

This study evaluated the influence of application time of self-etching primers on microtensile bond strength (μTBS) to dentin using three self-etching primer adhesive systems. Dentin surfaces were exposed from forty-eight human molars. They were conditioned with three self-etching primers (Clearfil SE Bond [SE], Unifil Bond [UF], Tyrian SPE + One Step Plus [TY]) and different primining times (10s, 20s, 30s and 40s). Composite resins were bonded to dentin surfaces and specimens were made. μTBS was tested and statistically compared using by one-way ANOVA and Tukey's Test. The results of this study presented that priming time for 10s in SE and UF groups and for 30s and 40s in TY group was highly decreased μTBS to dentin.

법랑질 접착에 대한 습윤 효과

고근호,조영곤,진철희,유상훈,김종욱,박병철,기영재,최희영,김종진 大韓齒科保存學會 2004 Restorative Dentistry & Endodontics Vol.29 No.3

This study evaluated the microleakage and interfacial gap between enamel and composite resin under the dry and wet condition of the enamel surface, V shaped class 5 cavities were prepared on the occlusal portion of extracted human molars. Samples were divided into three groups: D group (air dry for 10-15s), BD group (blot dry with moist cotton pellet), and DR group (air dry for 10-15s and rewet with Aqua-Prep F for 20s). Cavities were filled using Aelitefil composite resin after applied One-Step. Microleakage was tested by 2% methylene blue dye solution and the data were statistically analysed by Kruskal-Wallis test and Mann-Whitney test. Also Enamel-resin interface was observed under SEM. Group BD showed statistically lower microleakage than group D (p〈0.05). but there was no statistically significant difference between group BD and DR (p)0.05). At the enamel-resin interface, group D showed the gap of 2 ㎛ thickness, but group BD and DR showed close adaptation. In conclusion, the use of blot dry and rewetting agent (Aqua-Prep F) resulted in decreased microleakage and improved adhesion between enamel and resin when using One-Step.

복합레진의 지연충전이 미세인장 결합강도에 미치는 영향

박현식,조영곤,박병철,김종욱,최희영,김종진,진철희,유상훈,기영재 大韓齒科保存學會 2004 Restorative Dentistry & Endodontics Vol.29 No.3

The purpose of this study was to evaluate the effect of immediate or delayed composite resin filling on dentinal microtensile bond strength (μTBS) after applied the adhesive. The coronal dentin of human third molars was exposed. Single-Bond or One-Step was applied on the dentin surfaces, and composite resin were constructed immediately (group 1) or 5 min., 10 min., 15 min., 20 min. and 30 min. (groups 2-6) after an adhesive was applied. The specimens were sectioned and made bar-shaped. Each surface area of them was about l ㎟. The RBS test was performed by EZ test. The results were analysed by One-way ANOVA and Tukey's test at 95 % significance level. The results suggested that the μTBS of Single-Bond to dentin was decreased when the composite resin was constructed 20 min. and 30 min. after Single-Bond was applied. But the μTBS of One-Step was not affected by delayed composite resin filling.

고층건물 수직구조요소의 축소량 산출에 관한 연구

김희철,정은호 慶熙大學校 1997 論文集 Vol.26 No.-

An estimation of shortening in vertical members for the steel structure is not difficult to predict because of its characteristics of deformation. However. it is not easy to estimate the quantity of shortening for the concrete and composite structural systems. Total shortening of both concrete and composite vertical members should be obtained by separating the instantaneous elastic shortening and inelastic shortening caused of inelastic behavior of creep and shrinkage. The main purpose of estimating the total shortening of vertical structural members is to compensate the differential shortening between adjacent members. Differential shortening has to be estimated so that it can be ascertained whether the differential shortening effects are significant or not. If they are significant to effect other structural members, in the design of joints, and in architectural features so as to produce smaller differential effects. Column Shortening Calculation Program(CSCP) was developed to predict the shortening amount of vertical structural members. The developed program can estimate both elastic and inelastic shortening of reinforced concrete members. The verification CSCP was accomplished by comparing the results to the other program developed by Portland Cement Association(PCA).

무한고장 소프트웨어 신뢰성장 모형에 대한 최소자승법 모수추정에 관한 연구

김희철 남서울대학교 2007 남서울대학교 논문집 Vol.13 No.4

Finite failure NHPP models presented in the literature exhibit either constant, monotonic increasing or monotonic decreasing failure occurrence rates per fault. In this paper, Weibull distribution reliability model was reviewed. Parameter Estimation by least squares study for Infinite failure software reliability growth Model was employed. The numerical example by Minitab software random data was illustrated. Key words : Least squares, Finite failure NHPP model, reliability growth

상호 작용적 환경이 학교생활에 미치는 영향요인 분석 -산업경영공학 전공자 중심으로

김희철 남서울대학교 2008 남서울대학교 논문집 Vol.14 No.2

The purpose of the study is to investigate that the influence Factor of satisfaction of school life on psychological circumstances about the Industrial & Management Engineering Majors by physical environment, vision of job. These results by grade through the class's expectations, because of the different class's expectations, from these results , requires that the need of attention like to discussion survey, amount of learning and service activities etc. with the fitness. Events related to job satisfaction of school to help achieve a high correlation. As well as field work in the areas of Information and parallel to not majors field. In particular, girls need a map, is also a special job. The school factors that affect satisfaction with the general environment of Psychological circumstances predicted, but the job is a bigger vision and factors affecting the physical environment in the department was currently on the status of job education and school to work for a reason to be here. Key Words : satisfaction of school life, psychological circumstances

공정능력지수를 이용한 제조공정관리 실증분석

김희철 남서울대학교 2008 남서울대학교 논문집 Vol.14 No.-

From the subdivision of this analysis, basic plan needs the side of the quality control. In this paper, we discuss process capability analysis using process capability indexs. This paper‘s method is a system design and related industries to process their workers the ability to utilize the quality analyzes information in advance to help improve the quality of life, and the distribution of choice, there are one measure of using models can be used. The used software failure time data for capability analysis of process is Manufacturing Process Management data, the result of analysis listed on this chapter 3. The practical use is presented. Key Words : Process capability index elease Policies, Manufacturing Process Management data, Target Value, U. L

아파트 전세가격지수의 통계분석 및 예측에 관한 연구

김희철 남서울대학교 2011 남서울대학교 논문집 Vol.17 No.2

In this study, changes in apartment rental price index to analyze the February 2005 to September 2011 monthly rental price index, using the results of apartment rental price index is an average over a large apartment in a small apartment with high but variation range compared to the big show a higher number of small differences in the more than a large fluctuation appears, this highly compact and charter price index formation was higher in the past in recent years an increasingly large and small apartment appear highly similar or smaller than the increasingly large trends have shown that appear significantly higher. And large and small apartment rental prices are not the same exponent was found to average together. Apartment rental prices eventually predict the future, rather than a large apartment in a small apartment rental prices than a large mini's showing more and more drastically than in a small charter price formation is predicted to rise by more. This paper into the apartment, the seller, and marketing professionals with the information prior to their advantage this predict the future pattern of apartment rental prices might help identify environmental think you are feeding. The charter price index future with the environment approach to pattern and estimate repairs and repairs to the black part is expected to approach. Key Words :Monthly Rental Price Index, Explanatory Power, Levene Test for Equal Variances

여행사 고객 서비스 품질 특성 요인분석에 관한 연구

김희철 남서울대학교 2007 남서울대학교 논문집 Vol.13 No.3

The survey study on the influence factor Analysis of quality service elements for 285 customer service of a tourist agency carry out. In this survey, element of quality customer service(such as reliability, responsiveness, assurance, empathy etc.,) is considered. The purpose of this study is to examine element of quality customer service and to investigate the important factors affected by that. The results have processed through the analysis are summarized as follows. First, the determinative variables, such as reliability, assurance have had a positive influence, but elements of responsiveness and empathy have had a negative effected on that. Second, in factor analysis, power of explaining with 1 factor( unique duty of tourist agency) have had 19.8 %, power of explaining with 2 factor( members duty of the staff of tourist agency ) have had 12.6 %, the 3 factor( elements of customer service ) is 11.7 %. the 4 factor( elements of interest ) is 11 %, the 3 factor( elements of request and profit ) is 10 %. This results suggest that main element customer service of a tourist agency is factors such the unique duty of tourist agency, members duty of the staff of tourist agency, elements of customer service Keyword : Influence factor , Quality service, Determinative variable, Service of a tourist agency.