전기도금을 이용한 교정용 선재의 직경 증가에 관한 실험적 연구

조진형,김경근,황현식 전남대학교 치과대학 2001 구강과학 Vol.13 No.2

The purpose of this study was to evaluate the possibile clinical application of electroplating to increase diameter of an orthodontic wire, through examining the change of physical properties. The diameter of stainless steel orthodontic wire was increased from 0.016 inch to 0.018 inch by electroplating in a bath of nickel sulfate 100g/L, nickel chloride 60g/L, boric acid 30g/L, and sodium chloride 50g/L, under the conditions of 1.7V, 25∼29℃, and 3.1∼3.3pH. During the electroplating, the rate of diameter increase was measured every minute. To investigate uniformity, the diameter was measured at three different locations of each wire specimen after electroplating. An X-ray diffraction test was performed to analyze the nature of the electroplated metal. Following heat treatment to improve adhesion between the wire and electroplated metal, a three­point bending test was conducted to compare stiffness, yield strength, and ultimate strength among four wire groups; 0.016 inch, electroplated 016, electroplated and heat ­ treated 016, and 0.018 inch wires. Through the comparison of each wire group, following results were obtained. 1. In the lad ­ deflection graph, the curve of the eletoplated group was placed between that of the 0.016 inch group and the 0.018 inch group, and the curve closer to the 0.018 inch group by heat treatment. 2. In the electroplated and heat ­ treated 016 wire group, the values of stiffness, yield strength and ultimate strength showed higher tendency than in the original 0.016 inch group. Stiffness and ultimate strength showed statistically significant differences between two groups. 3. Stiffness, yield strength, and ultimate strength of electroplated wire presented lower values than those of 0.018 inch wire group. 4. stiffness, yield strength, and ultimate strength of electroplated and heat ­ treated wire showed higher tendency than those of electroplated wire group, and ultimate strength showed statistically significant difference between two groups. 5. After electroplating, the difference in diameter between the three locations was withing 0.1´0.3% variation, and showed no statistical significance.

黃菊과 黑薔薇를 이용한 기능성 花茶 개발 Ⅱ.花茶의 품질특성

조경숙,서정근,정형석 韓國植物ㆍ人間ㆍ環境學會 1999 인간식물환경학회지 Vol.2 No.2

본 연구는 화차의 비율별 제조공정에 따른 화차의 관능적 품질을 평가하기 위해서 수행되었다. 녹차와 꽃의 시료에 대한 색도중 L, a, b값은 녹차가 29.93, -8.24, 9.27로 녹색을, 황국은 47.20, -1.69, 29.12로 밝은 황색을, 흑장미는 37.18, 4.47, 4.12로 흑적색을 띠웠다. 색상과 채도는 황국이 -17.23과 29.17로 가장 높아 색상이 가장 밝고 선명하였으며, 흑장미는 0.92와 6.08로 색상이 어둡고 둔탁한 적색을 띠워 녹차에 꽃을 혼합할 경우 시각적으로 황국은 쉽게 구별이 되었으며 흑장미는 쉽게 구별되지 않았다. 황국 화차는 꽃의 비율이 증가할수록 국화향, 상쾌하고 개운한 단맛의 증가와 더불어 떫은 맛이 감소하였으나, 혼합비율이 9:2 이상일 경우에는 쑥냄새와 같은 강한 국화향이 증가하여 녹차 고유의 향은 거의 상쇄되는 경향이었다. 장미 화차는 장미꽃이 증가할수록 시큼한 장미향이 강하게 증가하였고, 탄닌성분이 많아 떫고 텁텁한 맛과 시큼한 맛이 강한 것으로 평가되었다. 녹차에 알맞은 꽃의 혼합율은 9:1이하의 비율로 혼합했을 때 황국과 흑장미의 꽃잎색이 녹차와 어울려 전체적인 조화성과 풍미, 시각적 아름다움을 증가시켰다. 녹차에 꽃을 혼합한 화차는 녹차 단일의 차보다는 시각적 즐거움과 독특한 방향성이 부가되어 맛과 향이 풍부한 기능성 꽃차 개발에 좋은 재료로 평가되었다. This experiment was carried out to investigate the effect of mixed ratio on the sensory evaluation in manufacture of functional flower tea. Among the chromaticity about green-tea and material flower, the amount of L, a, b of green tea was 29.93, -8.24, 9.27 with green, the amount of a yellow chrysanthemum(C.indicum) was 47.20, -1.69, 29.12 with bright yellow, the amount of a black rose(Rosa hybrida)is 37.18, 4.47, 4.12 with dark red. The yellow chrysanthemum has brightest and most distinct color with -17.23 hue and 29.17 chrome value, but the black rose has dark dead red color with 0.29 hue 6.08 chrome value. When the yellow chrysanthemum mixed with green tea, it was easily distinguished with naked eye. But the black rose was not distinguishable easily. As the retio increase, the yellow chrysanthemum tea has more chrysanthemum scent, increase of refreshing and relieved sweetness, and less astringent taste. If the mixed rate was over 9:2, original scent of green tea was almost offset with strong chrysanthemum scent like mugwort's. As the ratio increase, the rose tea has strongly increased sourish, and because of the tannin it was appraised strong astringent, unpleasant, sourish taste. The best-mixed ratio of green tea and flower is 9:1. When it mixed at this ratio, the yellow chrysanthemum and petal color of black rose was well matched with green tea, and the tea has general harmony and flavor and it is visually beautiful. Flower tea, green tea from flower, has added visually joy and unique fragrance, it was valued as fine material for rich taste and scent technical tea development.

남북정상회담 분석

조경근 경성대학교 2000 論文集 Vol.21 No.2

안면비대칭 정도에 따른 정모 두부방사선사진관 3차원영상의 비교 연구

조홍규,김경근,황현식 전남대학교 치과대학 2001 구강과학 Vol.13 No.2

The purpose of this study was to find out the problems of P ­ A cephalometric measurements used in the facial asymmetry analysis and to show the necessity of using three ­ dimensional morphometry. Steel ball (1.2㎜ in diameter) were attached in twenty seven landmarks of symmetrical artificial human skull, and eighty seven different asymmetrical artificial human skulls were formed by enlarging gradually remus height, mandibular body length, and gonial angle of the hemiface. From the P ­ A cephalometry and three ­ dimensional morphometry of each skull types, three linear measurements (representing ramus height, mandibular body length, mandibular length) and two angle measurements (representing gonial angle, menton deviation) and two area measurements (representing mandibular area, lower facial area) were acquired and made into asymmetry index. Menton deviation itself was used as asymmetry index while left ­ right differences were used in the other measurements. These asymmetry index were compared with each other to show the different aspect of the seven asymmetry index according to the degree of actual facial asymmetry. Through the statistical analysis, following results were obtained. 1. When actual ramus height difference becomes large, menton deviation and lower facial area asymmetry index of P ­ A cephalometry were reduced significantly more than those of three ­ dimensional morphometry (p<0.001). 2. When actual mandibular body length difference becomes large, ramus height, lower facial area asymmetry index of P ­ A cephalometry were reduced significantly (p<0.001) while mandibular body length, mandibular length, gonial angle, and mandibular area asymmetry index of P ­ A cephalomentry were magnified significantly more than those of three ­ dimensional morphometry (p<0.01). 3. When actual gonial angle difference becomes large, gonial angle asymmetry index of P ­ A cephalometry was reduced significantly (p<0.001) while lower facial area, mandibular body length, and mandibular area asymmetry index were magnified significantly more than those of three ­ dimensional morphometry (p<0.01). 4. When the correlation between actual ramus height difference and seven asymmetry index of P ­ A cephalometry and three ­ dimensional morphometry was analysed, no difference between P ­ A cephalometry and three ­ dimensional morphometry was found (p<0.01). 5. When the correlation between actual mandibular body length difference and seven asymmetry index of P ­ A cephalometry and three ­ dimensional morphometry was analysed, significance was found in mandibular body length, mandibular length, menton deviation, mandibular area, and lower facial area (p<0.001) while significance was found only in gonial angle of three ­ dimensional morphometry (p<0.01). 6. When the correlation between actual gonial angle difference and seven asymmetry index of P ­ A cephalometry and three ­ dimensional morphometry was analysed, significance was found in gonial angle (p<0.001) while significance was found only in lower facial area of three ­ dimensional morphometry (p<0.01). The above results suggest that three ­ dimensional morphometry show to be necessary for the accurate facial asymmetry analysis.

최적배치를 위한 워드모델 및 비트연산자 개발

김영근,조경호 제주대학교 공과대학 첨단기술연구소 2006 尖端技術硏究所論文集 Vol.17 No.1

In this paper, a new nesting method based upon the 'word representation' of parts and raw sheets is proposed to improve the performance of pixel-based nesting. In this new representation, the pixel patterns of parts and sheets are converted to proper word-sets. And all the usual nesting processes such as part allocations, de-allocations, overlap testings and etc. can be performed through the 'bit operations' between words of the parts and sheets. The proposed method shows some possibilities to overcome the shortcomings of the traditional pixel-based nesting. In addition, a new efficient gap searching method based upon the quad-tree is presented to locate proper allocation positions of the parts.

간경변 환자에서 Oro-cecal Transit Time의 측정

원경준,이준,변유미,조민근,조주연,서정균,김영대,박찬국,김만우 朝鮮大學校 附設 醫學硏究所 2008 The Medical Journal of Chosun University Vol.33 No.2

Background: Neurotransmitter like substances in the gut have been proposed to contribute to the overall portal systemic encephalopathy (PSE). The source of the ammonia in patients with PSE is mainly the small bowel, as a result of the conversion of glutamine in the diet to glutamate and ammonia. PSE is highly responsive to changes in diet, to antibiotic therapy and to ingestion of nondigestible disaccharides such as lactulose. This study was performed to evaluate the relationship between PSE and oro-cecal transit time. In addition, performed to evaluate the effect of severity, cause, complications of liver cirrhosis on oro-cecal transit time. Methods: Between August 2006 and February 2007, 48 cirrhotic patients consecutively was enrolled in study their oro-cecal transit time after informed consent was obtained. A non-invasive hydrogen breath test was used to study oro-cecal transit time (OCTT). Result: The OCTT were delayed in cirrhotic patients with PSE compared without PSE (123.3 ± 42.7 min vs 170.0 ± 58.3 min, p<0.05). OCTT tended to prolongate further as the damage in the liver got worse, nevertheless the result was statistically meaningless (p<0.111). Neither presence of ascites or cause of PSE had any influence on gastrointestinal transit. Conclusions: Cirrhotic patients with PSE have more delayed OCTT than without PSE. Further research is needed to find out the relationship between OCTT and severity of liver cirrhosis.

제 1형 신경섬유종증 환자에서 발생한 위장관 간질종양 1예

원경준,이준,변유미,조민근,한경택,김원,홍란,임성철,김경종,김영대,박찬국,김만우 朝鮮大學校 附設 醫學硏究所 2007 The Medical Journal of Chosun University Vol.32 No.2

Gastrointestinal stromal tumor (GIST) is the most common non-epithelial neoplasm arising in the gastrointestinal tract, but this tumor is rarely seen in association with type l neurofibromatosis (NFl) Generally, the majority of GISTs are isolated neoplasm and they are sporadically found in the stomach, but the GISTs in NFl patients are usually multiple and usually found in the small intestine. We report a case of multiple GISTs in the jejunum of a 63-year-old woman diagnosed as NFl accompanied by complication of gastrointestinal bleeding, In this case, Patient had multiple cafe-au lait spots and neurofibroma on skin and had freckling on axilla and groin, and then, we made a diagnosis of NFl. Gastrointestinal bleeding is controlled by resection of multiple GISTs. Generally, only 3-5% of all gastrointestinal bleeding comes from the small bowel. Causes of small intestinal bleeding are angiodysplasia, neoplasm, NSAIDs induced ulcer etc. but, If patients have NFl accompanied by complication of gastrointestinal bleeding, GISTs on small bowel must be considered.

黃菊과 黑薔薇를 이용한 기능성 花茶 개발 Ⅰ.花茶의 製茶 前後의 理化學的 特性

서정근,조경숙,방극필 韓國植物ㆍ人間ㆍ環境學會 1999 인간식물환경학회지 Vol.2 No.2

본 연구는 화차의 비율별 제조공정에 따른 이화학적 특성을 조사하기 위하여 수행되었다. 건조전 수분함량은 흑장미나 황국에 비해 녹차가 85.3%로 가장 높았으나 건조 후 수분량은 녹차가 4.55%인데 비해 황국화와 흑장미가 7.42와 7.45%로서 꽃이 수분함량이 높게 나타났다. 조지방은 황국화 5.17%, 흑장미 3.70%, 녹차 2.12%순으로 향이 강한 황국이 가장 높았으며, 총엽록소는 녹차가 499.8(㎎/100g)로 가장 높은데 비해 황국화는 29.8%, 흑장미는 엽록소가 없는 것으로 나타나 엽을 이용하는 부위와 꽃잎을 이용하는 부위의 엽록소 함량 차이가 큰 것으로 나타났다. 조섬유와 조회분은 녹차가 7.59%, 4.82%로 식용꽃에 비해 함량이 높았다. Tannin은 흑장미가 18.99%로 가장 높았으며, 녹차가 14.21%, 황국화가 4.18%순으로 시료간의 성분함량 차이가 컸었다. caffeine은 녹차에서만 3.17%를 함유하고 있었으나 꽃에서는 카페인 성분이 없었다. 칼로리는 전체적으로 비슷한 경향치를 보였으나 흑장미가 가장 낮은 열량을 보였으며, 무기성분함량은 황국이 칼륨 2.57%, 칼슘 0.55%, 마그네슘 0.35%로 전체적으로 녹차와 흑장미보다 높았다. 녹차와 꽃을 혼합한 비율시험에서 처리별 탄닌, 유리아미노산, 전질소, 조지방 및 카페인 변화량은 녹차가 꽃시료보다 함량이 높을 경우 녹차의 혼합비율이 높을수록 비율별 일정하게 증가하는 경향을 보였으나 낮은 경우에는 그 반대 경향을 보였다. This experiment was carried out to investigate the effect of mixed ration on the quality characteristics in manufacture of functional flower tea before dried was 85% and the level of moisture content was higher than the yellow chrysanthemum(C.indicum) and black rose(Rosa hybrida). Yet green tea has 4.55% moisture content after dried, moisture content of flower after dried was higher as the yellow chrysanthemum and black rose have 7.42% and 7.35% moisture content. The yellow chrysanthemum with strong scent has the highest fat among green tea 2.12%, black rose 3.70%, and yellow chrysanthemum 5.17%. Green tea highest chlorophyll as 499.8%(㎎/100g), but yellow chrysanthemum has 29.8% and black rose has none. There was a big difference in chlorophyll between a leaf and a petal. Green tea has higher fiber and lime (7.25%, 4.82%) than esculent flower. There was a large ingredient content difference. Black rose has the highest tannin 18.99%, green tea has 14.21%, and yellow chrysanthemum has 2.12%. Only green tea has caffeine 3.17%, and not in flower. Generally they have similar amount of calorie, but block rose has least. The inorganic ingredient content of yellow chrysanthemum is potassium 2.57%, calcium 0.55%, magnesium 0.35% and green tea mixed-rate was higher and higher, tannin, free amino acid, nitrogen, fat, and caffeine are increased regularly in the ratio test of green tea with flower. But if green tea has less content than material flower, they are opposite.

악교정 환자의 악교정 수술전후 발음양상에 대한 비교연구

권경환,김수남,이동근,조용민,이숙향 대한악안면성형재건외과학회 2000 Maxillofacial Plastic Reconstructive Surgery Vol.22 No.2

The purpose of this study was undertaken to determine the effects of orthognathic surgery on speech. The hyposis stated herein is that functional behaviors of the dentofacial complex, such as speech production, may be adversely affected by deviations of a structural nature(especially, Class III malocclusion) . Twenty adults with Class III malocclusion(13 female and 7 male) were studied preoperative, immediate postoperative and either 6 or 12 months postoperative lateral cephalograms. They had mandibular prognathism and had undergone mandible setback operation. The position of tongue, soft palate(Uvula), hyoid bone, respiratory track width, and pharyngeal depth were assessed on lateral cephalograms with 23 cephalometric variables, ANOVA, Paired t-tests and Pearson's product-moment correlation coefficient tests were used to evalute the operative changes in all cephalometric parameters. A experienced speech and language pathologists performed narrow phonetic transcriptions of tape-recorded words and sentences produced by each of the ninth patients and the recording tapes were analyzed by phonetic computer program(Computerized Speech Lab(CSL) Model 4300BI(U.S.A.)) These judges also recorded their ratings of each patient's overall consonants, hypernasality, hyponasality, and articulation proficiency. The results obtained are as follows ; 1.There were significant changes in distance of posterior pharyngeal wall to tongue (TI-TW2, TS-TW3) after the surgery at 6 months postoperatively(each p<0.01 p<0.05) 2.The posterior tongue point(TI, TS, PPT) moved posteriorly after surgery and remained to its changed position at 6 months postoperatively(p<0.05) . The displacement of tongue was correlated with the movement of mandibular setback amount(p<0.05). The hyoid bone moved posteriorly superiorly after immediate postoperative period. There was significant changes in hyoid bone movement after immediated post-operative period(p<0.05), but returned to its original position during the follow-up period(p>0.05) 3.The soft palate was displaced posteriorly superiorly after immediated operative period and remained to its changed position at 6 months postoperatively(p<0.05) ANS-PNS-SPT angle increasing, PPU-PPPo distance narrowing was showed after surgery, and remained its appearance 6 months postoperactively (p<0.05) 4.There were significant changes in formant value and squre diagram of vowel sound after the orthognathic surgery and the follow-up period. There were significant changes in /ㅅ/sound and posterior tongue sound. 5.The posterior movement of tongue and the posteriosuperior movement of soft palate was correlated with mandibular setback amount after orthognathic surgery. On the vowel squre diagram, the author found that the place of articulation after operation moved downward, backward, upward. 6.In assessing speech abnormalities, dental occlusion should be considered as a contributing factor. The vast majority of subjects with preoperactive misarticulations eliminated or reduced their errors following orthognathic surgery. There was significant difference in speech impovement between pre- and post-operation.

Air-coupled 트랜스듀서를 이용한 발전설비 배관에서의 유도초음파 모드 규명

박익근,김현묵,김용권,송원준,조용상,장경영,조윤호 한국비파괴검사학회 2004 한국비파괴검사학회지 Vol.24 No.4

발전설비의 중요한 요소인 배관의 효율적인 비파괴검사를 위해, 배관내에 유도초음파를 comb 트랜스듀서를 이용하여 발생시켰으며, 유도초음파를 비접촉 방식으로 수신하기 위해 ACT(air-coupled transducer)를 적용하였다. comb 트랜스듀서의 요소간격과 이론적인 분산선도로부터 발생가능 한 유도초음파 모드가 예측되었다. 또한 예측된 모드를 수신하기 위해 각 모드의 이론적인 위상속도를 이용하여 ACT의 수신 각도를 결정하였다. 수신모드의 특성을 규명하기 위해 웨이블릿 변환과 2D-FFT를 이용한 시간-주파수해석을 수행하여 이론적인 분산선도와 비교한 결과, 수신된 모드는 이론적으로 예측된 모드와 일치하는 것으로 나타났다. In order to inspect the piping effectively, one of the important components in the facility of power plants, the ultrasonic guided wave was generated by a comb transducer and was received in a non-contact fashion by using an air-coupled transducer. The guided wave modes that can be generated by the comb transducer in piping are predicted from the theoretical dispersion curves and the element spacing of a comb transducer. Moreover, to receive the specific modes, the receiving angle of the air-coupled transducer is calculated from Snell's law between the phase velocities of guided waves and the sound velocity of air. The guided wave modes obtained in experiments are identified from the result of time-frequency analysis such as wavelet transform and two-dimensional fast Fourier transform.