강건 설계를 이용한 전자제품 신뢰성 향상방법

김경모,이지수,신호균 金烏工科大學校 1997 論文集 Vol.18 No.-

Reliability is one of the important quality factor in electronic products. As it is time-consuming to estimate mean time to failure, it has not been integrated in the process of product design. In this study, we propose a method which can optimize the product with respect to robustness design and can estimate mean time to failure of electronic products by only one experimentation. This proposed method can quarantee quality improvement by making the life time of the designed products robust to customer's environment. We explaine the detailed steps of this proposed method through a case study.

의원성 사고로 발생한 타액선염 : 증례보고

김현우,허경회,이원진,허민석,이삼선,최순철 대한구강악안면방사선학회 2004 Imaging Science in Dentistry Vol.34 No.2

A case of sialadenitis is presented in a patient with painful swelling of the right mouth floor. The condition was caused by trauma on the right mouth floor during dental treatment, which had happened 15 days before admission. On aspiration, mucous secretion was found and ultrasonography showed obstruction of duct. Histopathological studies and surgical investigation established a definite diagnosis of obstructive sialadenitis caused by ductal laceration. As surgical treatment sialodochoplasty was selected. The case and relevant considerations are discussed.

키토산-옥타노테이트 필름의 표면성질 평가

김병운,김경희 한국공업화학회 2003 응용화학 Vol.7 No.2

Derivative of chitosan was synthesized by reacting chitosan with octanoic acids. The contact angles on chitosan-octanotate film were measured using dispersion(D), polar(P) and hydrogen(H) liquids. All nonpolar liquids of alkane homologues easily spread on the surface of chitosan octanotate film. On the other hand, polar or hydrogen-bonding liquids form a certain angle on the surface of chitosan-octanotate film. The critical surface tensions Y_(c) of chitosan-octanotate film were evaluated by the Zisman plot(cosθ versus Y_(L)) and the other plots, New functional film for MA packaging was developed to understand the relationship between surface chemistry and wettability of chitosan-octanotate film.

Chitosan-laurate 필름의 표면성질

김병운,김경희 한국공업화학회 2004 응용화학 Vol.8 No.1

Derivative of chitosan was synthesized by reacting chitosan with acetic acids. The contact angles on chitosan-laurate film were measured using dispersion(D), polar(P) and hydrogen(H) liquids. All nonpolar liquids of alkane homologues easily spread on the surface of chitosan-laurate film. On the other hand, polar or hydrogen-bonding liquids form a certain angle on the surface of chitosan-laurate film. The critical surface tensions V_(s) of chitosan-laurate film were evaluated by the Zisman plot(cos Versus V_(L)) and the other plots. New functional film for MA packaging was developed to understand the relationship between surface chemistry and wettability of chitosan-laurate film.

MA Packaging용 Chitosan-Palmitate 필름의 표면특성화

김용권,김병운,김경회 한국공업화학회 2002 응용화학 Vol.6 No.2

Derivative of chitosan was synthesized by reacting with palmitic acid. The contactangles on chitosan-palmitate film were measured using dispersion(D), polar(P) andhydrogen(H) liquids. All nonpolar liquids of alkane homologues esily spread on thesurface of chitosan-palmitate film. On the other hand. polar or hvdrogen-bondingliquids from a certain angle on the surface of chitosan-palmitate film. The criticalsurface tensions vo of chitosan-palmitate film were estimated by the Zisman plot(cosθ versus νL) and other plots. New functional film for MA packaging have beendeveloped to understand the relationship between surface chemistry and wettability ofchitosan-palmitate film.

BPDA-MDA Polyimide 표면특성 평가

김경회,김혜숙 한국공업화학회 2005 응용화학 Vol.9 No.1

The behavior of dielectric material and manufacturing process of polyimide can be optimized by understanding relationship between surface chemistry and the wettability of polyimide. A general and useful method to predict the wettability of polyimide is to measure contact angle, which provides the information on surface tension, morphology and heterogeneity of the surface of polyimide. This research improves the existed repetitive and inexact method of measuring contact angle, and the improved measurement of contact angle can be reproducible and exact by capturing the image of the sessile drop on BPDA-MDA polyimide film and analyzing the image quantitatively. All nonpolar liquids of alkane homologues easily spread on the the surface of BDPA-MDA polyimide. On the other hand, polar or hydrogen-bonding liquids form a certain angle on the surface of BPDA-MDA polyimide. Critical surface tension of BPDA-MDA polyimide estimated from Zisman plot is smaller than that calculated from the plot of 1+cosθ vs. 1/γ_(L)^(0.5) plot or the plot of log (1+cosθ ) vs. logγ_(L) plot.

신·재생에너지 자원으로 유기성 폐기물 재활용

김경회 대구대학교 산업기술연구소 2014 産業技術硏究 Vol.25 No.1

In view of new·renewable energy and the recycling of waste resources, this SIG study suggests that fry-drying technique using boiling heat transfer can convert yearly increasing organic wastes to solidified fuel source. Solidified fuel from organic wastes can be produced from lab-scale batch reactor and pilot-scale continuous process, its calorific value shows good quality ranging from 5,000 to 5,500 ㎉/㎏ and the advantage of low cost fuel can also be made through mass production.

방사선사진에서의 골질과 임상적으로 평가한 골질 분류의 상관관계

김현우,허경회,박관수,김정화,이원진,허민석,이삼선,최순철 대한구강악안면방사선학회 2006 Imaging Science in Dentistry Vol.37 No.1

Purpose : To investigate the validity of digital image processing on panoramic radiographs in estimating bone quality before endosseous dental implant installation by correlating bone quality in radiographic images with clinical bone quality classification. Materials and Methods : An experienced surgeon assessed and classified bone quality for implant sites with tactile sensation at the time of implant placement. Including fractal dimension eighteen morphologic features of trabecular pattern were examined in each anatomical sites on panoramic radiographs. Finally bone quality of 67 implant sites were evaluated in 42 patients. Results : Pearson correlation analysis showed that three morphologic parameters had weak linear negative correlation with clinical bone quality classification showing correlation coefficients of -0.276, -0.280, and -0.289, respectively (p<0.05). And other three morphologic parameters had obvious linear negative correlation with clinical bone quality classification showing correlation coefficients of -0.346, -0.488, and -0.343 respectively (p<0.05). Fractal dimension also had a linear correlation with clinical bone quality classification with correlation coefficients -0.506 significantly (p<0.05). Conclusion : This study suggests that fractal and morphometric analysis using digital panoramic radiographs can be used to evaluate bone quality for implant recipient sites. (Korean J Oral Maxillofac Radiol 2006; 36 : 25-32)

디지털 및 일반 측방두부규격방사선사진에서 측정 방법에 따른 계측치의 비교

김미자,허경회,이원진,허민석,이삼선,이진구,안병근,최순철 대한구강악안면방사선학회 2005 Imaging Science in Dentistry Vol.35 No.1

Purpose : To compare cephalometric measurement between measuring methods in digital and conventional lateral cephalometric radiograph. Materials and Methods : Twenty digital and conventional lateral cephalometric radiographs were selected. In digital group, cephalometric measurements were performed manually using hardcopies and automatically using VCeph^(TM) program on the monitor. In conventional group, the same measurements were performed manually on conventional films, and for automatic measurement conventional films were digitized by scanner. All measurements were performed twice by 4 observers, and 24 cephalometric variables were calculated and the time spent for each measurement was recorded. The differences in measurements data and the time spent for each measurement were compared within each group. Intra-observer and inter-observer comparisons were performed. Results : In both groups, no statistically significant difference between manual and automatic measurements was observed and most of the variables didn’t show statistically significant differences between methods. The observer with less experience tended to show statistically significant differences of measurements between methods, and differences from other observers. The differences of measurements between methods in digital group were lesser than those of conventional group with statistical significance in 8 variables out of 24. With automatic method and in digital group, the spent time was shorter. Conclusion : With direct digital radiograph, automatic method using manually idenitified landmarks can be preferable in cephalometric analysis.

정량적 영상법을 이용한 BPDA/BAPP 폴리이미드 계면현상 평가

김경회 한국공업화학회 2004 응용화학 Vol.8 No.2

The behavior of dielectric material and manufacturing process of polyimide can be optimized by understanding relationship between surface chemistry and the wettability of polyimide. A general and useful method to predict the wettability of polyimide is to measure contact angle, which provides the information on surface tension, morphology and heterogeneity of the surface of polyimide. This research improves the existed repetitive and inexact method of measuring contact angle, and the improved measurement of contact angle can be reproducible and exact by capturing the image of the sessile drop on BPDA/ EDA polyimide film and analyzing the image quantitatively. All nonpolar liquids of alkane homologues easily spread on the the surface of BDPA/EDA polyimide. On the other hand, polar or hydrogen-bonding liquids form a certain angle on the surface of BPDA/EDA polyimide. Critical surface tension of BPDA/EDA polyimide estimated from Zisman plot is smaller than that calculated from the plot of 1+cosθ vs. 1/Υ 1^(o.5) plot or the plot of log (1 +cosθ) vs. logγ_(L) plot.