象牙質 表面處理가 글라스 아이오노머 시멘트의 邊緣漏出에 미치는 影響에 關한 硏究

趙正熙,洪燦義 단국대학교 치의학연구소 1992 논문집 Vol.4 No.-

The purpose of this study was to evaluate the effect of the dentin pretreatment on the marginal leakage of a glass ionomer cement. In this study, 60 molars with sound and healthy crown portion were used. The dentin surface of these teeth were exposd and polished with 600 grit silicon carbide paper. Square-shaped cavities were prepared on the flattened dentin surfaces and these were divided in to 4 groups according to the dentin pretreatment procedures. Group Ⅰ : Dentin pretreatment with distilled water as a control group. Group Ⅱ : Dentin pretreatment with 5% sodium hypochlorite solution. Group Ⅲ : Dentin pretreatment with Ketac conditioner. Group Ⅳ : Dentin pretreatment with 40% polyacrylic acid. The degrees of dye penetration in the cavity walls were assessed using a stereoscope at x40 magnification according to the maximum dye penetration. The results were analyzed by using Mann-Whitney U test. The results were as follows : 1. All goups showed varying depth of dye penetration. 2. Distilled water group showed the most severe marginal leakage when compared with the other groups(P<0.05). 3. 40% polyacrylic acid group showed the least amount of marginal leakage compared with the other groups(P<0.05). 4. There were significant differences between Group Ⅰ(distilled water) and Group Ⅳ (40% polyacrylic acid)(P<0.05), but there were no significant differences among Group Ⅰ (distilled water), Group Ⅱ (5% sodium hypochlorite), Group Ⅲ (Ketac conditioner)(P>0.05)

예혼합 난류유동장내 점화핵의 난류화염두께 및 난류화염속도의 예측

조성찬,문희장 한국항공대학교 항공우주산업기술연구소 2003 航空宇宙産業技術硏究所 硏究誌 Vol.13 No.-

The propagation of a flame front subjected in a given intensity of turbulent flow is numerically investigated using the presumed PDF methods. The main characteristics of a turbulent flame thickness is also calculated in order to capture the basic behavior of a turbulent flame. It was found that the proposed models can achieve the prediction of these fundamental properties of turbulent flame, and demonstrate the capacity of probability density function based statistical model. A spherical coordinate is used to simulate the on growing kernel characteristics at the early stage of spark event. The result shown for the turbulent flame thickness allowed us that this method have the potential and can be extended to low Damko¨hler number regime. A more concrete analysis is expected in the future with a more elaborated chemical reaction model.

光彈性 實驗에 依한 2次元 應力 解析의 考察

趙熙燦 忠州大學校 1986 한국교통대학교 논문집 Vol.20 No.1

When we design members of machine and structures, We must think the importance of stress analysis. The are theoritical method and experimental method in stress analysis There are photoelastic method, strain gage method, brittle-Coating method and etc. in experimental stress analysis . In this paper, I considered stress distribution and stress concentration in epoxy specimen that had v-notches by photoelasic experimental method, and the purpose of this paper is extension and Complement of conclusion that was gained by other methods, and complehension of photoelastic experimental method.

와전류검사에 의해 검출된 증기발생기 전열관의 균열 특성

조찬희,남민우,김영호,양승한,이희종 한국비파괴검사학회 2004 학술대회 논문집 Vol.- No.-

The flaws detected at the steam generator tube of the Nuclear Power Plant are the wear indications by anti-vibration bars and circumferential cracks at the top of the tubesheet. It is easy to detect and size wear indications. Also the wear indications are commonly found at the steam generator tubes. However, the steam generator tube which includes crack indication is plugged because it is very difficult to predict the growth rate and the sizing error is high. The motorized rotating pancake coil has been used for the detection of circumferential crack since it is not possible to detect using the conventional bobbin probe. This paper describes the characteristics for the circumferential crack at the steam generator tubes of the Korean Standard Nuclear Power Plants.

퍼지 추론을 이용한 피로균열성장단계의 특성화

趙熙燦 충주대 2001 한국교통대학교 논문집 Vol.36 No.1

The estimation of fatigue crack growth and fatigue life prediction of machinery and structures is important in design.There are three stages of fatigue crack growth.Characterization of each stage cannot be performed manually because of the massive amount and fuzziness of data.This paper proposes a new algorithm for characterization of the stage of fatigue crack growth using fuzzy inference.This method enables us to mechanically characterization without manual computation.

스트레인 게이지법을 이용한 박판의 응력확대계수 측정

조희찬 충주대학교 2006 한국교통대학교 논문집 Vol.41 No.-

The measurement of the K_I stress intensity factor by using a strain gauge is studied experimentally. The specimen of double edge cracked tension plate is used. Attached position and orientation of strain gauge should be seriously considered the size of plastic zone in crack tip in the single gauge method. The value of measurement is compared with the proposed equation and the result has turned out to be fairly satisfactory.

산발성 장형 위선암 환자의 Microsatellite Instability와 병리학적 양상

조창희,홍유찬,안지현,최경현,이상호,신영명,윤기영,정민정,장희경 고신대학교의과대학 2007 고신대학교 의과대학 학술지 Vol.22 No.2

Background : Through many researches, microsatellite is expected to be a good diagnositic and prognostic factor in colorectal cancer, endometrial cancer, gastric cancer, and the others. The prevalence of microsatellite instability (MSI) in gastric carcinoma has reported variously, 13~44%. Purpose : We aimed to determine the prevalence of MSI-high and the relationship between MSI and pathological characteristics of sporadic intestinal type adenocarcinoma of stomach. Material and Methods : We analyzed 106 sporadic intestinal type adenocarcinoma specimens excised from patients who were over thirty-five years old to determine the statue of microsatellite by DNA sequencing. The tissues were formalin-fixed and paraffin embedded. DNA were extracted and amplified by polymerase chain reaction (PCR). MSI was determined using five markers recommended by National Cancer Institute (NCI). Specimens were also studied with five patholical factors-differenciation of tumor cells, depth of invasion, lymph node metastasis, vessel invasion, and perineural invasion- to determine pathological state. Result : The microsatellite statue was determined as MSI-High in 5 cases (4.7%), no MSI-low, and MSS (microsatellite stable) in 101 cases (95.3%). Within the frequency, there was no large gap in the distinction of gender in MSI cases, but in MSS cases, there was three-times more cases in male. MSI cases had moderate-to-poor differenciation and trend to invade toward serosa. All MSI cases showed no perineural invasion. But we could not find any statistical significance between MSI and pathological characteristics of sporadic intestinal type adenocarcinoma. Conclusion : Results suggest that MSI can not make any certain pathological significance in sporadic intestinal type adenocarcinoma. Even though less than 5% of sporadic intestinal type adenocarcinoma patients showed MSI, it can be used as a influential prediagnostic factor of gastric cancer. Further study with large scale of cases will be followed to verify these results.

경계요소법을 이용한 방음벽의 형상에 따른 음향방사특성해석

趙熙燦 忠州大學校 1997 한국교통대학교 논문집 Vol.32 No.1

The boundary element method is widely used for acoustic problems. This paper also is concerned with an application of the B.E.M. for the analysis of sound radiation characteristics of different shapes of soundproofing wall. The relations between various shapes of soundproofing wall and sound fields have been studied. And soundproof effect at geometrical viewpoint on the assumption of no diffraction have been considered. Generally, this study presents that the soundproof area of end-slanted walls becomes wide in the case of near field and that soundproof area of end-straight walls becomes wide in the case of far field. Based on these results, I suggest a more decisive design data of shape of soundproofing wall for effective soundproofing due to various sound fields.

최적해석을 위한 2차원 자동경계요소 생성법

趙熙燦 忠州大學校 1996 한국교통대학교 논문집 Vol.31 No.1

This paper deals with the self-adaptive mesh refinement technique for structural analysis using the boundary element method for two dimensional problems with linear elements. The algorithm in this paper is simple for error estimations and mesh refinement. I used the h-refinement. The numerical results for some problems show the validity and usefulness of the adaptive procidyre in this paper.

리스페달 정(리스페리돈 2㎎)에 대한 리스펜 정의 생물학적 동등성

조혜영,박은자,강현아,백승희,이석,박찬호,문재동,이용복 한국약제학회 2004 Journal of Pharmaceutical Investigation Vol.34 No.2

The purpose of the present study was to evaluate the bioequivalence of two risperidone tablets, Risperdal (Janssen Korea Co., Ltd) and Rispen (Myung In Pharm. Co., Ltd), according to the guidelines of Korea Food and Drug Administration (KFDA). The risperione release from the two risperidone formulations in vitro was tested using KP Ⅷ Apparatus Ⅱ method with various of dissolution media (pH 1.2, 4.0, 6.8 butter solution and water). Twenty four healthy male subjects, 23.33±2.10 years in age and 69.24±8.05 kg in body weight, were divided into two groups and a randomized 2×2 crossover study was employed. After one tablet containing 2 ㎎ as risperidone was orally administered, blood was taken at predetermined time intervals and the concentration of risperidone in serum were determined using HPLC method with UV detector. The dissolution profiles of two formulations were similar at all dissolution media. Besides, the pharmacokinetic parameters such as AUC_(t), C_(max) were calculated and ANOVA test was utilized for the statistical analysis of the parameters using logarithmically transformed AUC_(t), C_(max) and untransformed T_(max). The results showed that the differences between two formulations based on the Risperdal were 0.20, -1.29 and -11.09% for AUC_(t), C_(max) and T_(max), respectively. There were no sequence effects between two formulations in these parameters. The 90% confidence intervals using logarithmically transformed data were within the acceptance range of log(0.8) to log(1.25) (e.g., log(0.90)∼log(1.03) and log(0.84)∼log(1.09) for AUC_(t) and C_(max), respectively). Thus, the criteria of the KFDA guideline for the bioequivalence were satisfied, indicating Rispen tablet and Risperdal tablet were bioequivalent.