RUS법에 의한 Micro-Crack을 가진 Ferrule의 주파수 특성 평가

백경윤,이길성,양순호,김성훈,조영재,민한기,양인영 朝鮮大學校 機械技術硏究所 2003 機械技術硏究 Vol.6 No.2

광섬유 정렬부품으로 사용되는 페롤은 극히 높은 정밀도를 요하는 제품으로서, 높은 치수 정밀도와 결함이 포함되지 않는 등 높은 신뢰성이 요구되는 제품이다. 이러한 페롤의 형상결함평가에 종래의 광학현미경 평가법과는 달리. 본 논문에서는 공명초음파법(ResonantUltrasound Spectroscopy)을 이용하고자 한다. 공명초음파법이란 결함이 없는 시험편을 기계적으로 진동시켰을 때의 공진 주파수와 시험편 내에 결함을 가지고 있을 때의 공명 주파수 양상을 비교 분석하여 결함유무를 검출해내는 방법이다. 본 연구에서는 양품과 크랙을 가진 시험편을 현장에서 직접 사용되고 있는 광학현미경에 의해 분류를 한 다음, 더욱 정확한 측정을 위해 SEM에 의해 다시 분류하였다. 각각에 대해 공진 주파수를 측정하였고, 이 데이터의 검증을 위해 FEM해석을 수행하였다. 실험으로부터 얻는 양품의 공진 주파수와 FEM해석을 통해 얻었던 양품의 공진 주파수의 오차는 1∼2%정도의 범위를 벗어나지 않음을 알 수 있었다. 또한 크랙에 대한 공진 주파수를 측정하여서, 양품의 공진 주파수와 비교를 행하였고, 이 데이터를 가지고 모드별로 히스토그램을 그려서, 그것으로부터 현장에서 실제로 이용 가능한 모드를 존재함을 확인하였다. The Ferrule which is used as the product optical fiber very precisely, is required high to set the optical axes of an dimensional precision, lack of defect and high expectation. Up to now the optical instrument has been used for the defect and shape inspection of the Ferrule, but in this paper we examined the detectable defect and expectation by using the Resonant Ultrasound Spectroscopy (RUS). The RUS is the measurement' which is to excite specimen and to inspect the difference of natural frequency pattern between acceptable specimen and specimen has some defects. In this paper, we classified specimens into three groups by using She optical instrument; acceptable specimen A-type, 3-type and specimen A-type which has crack. And we reclassified by Scanning Microscope to carry out the more exact measurement. We surveyed the resonant frequency of every specimen, and carried out the simulation from the explicit finite elements code, NasEran t o verify the experiment data. The average error between the resonant frequency of acceptable specimens which is obtained from experiment and that from FEM analysis is in the range of 1-2 percentage. Also, we measured the resonant frequency of specimen which has crack, and compared that of acceptable specimen. We drew histogram by using these data, and confirmed the available mode in the plant.

文化財 保護區域 周邊 現狀變更 實態에 關한 硏究 : 京畿道를 中心으로

백승석,김용기 한국정원학회 2002 한국전통조경학회지 Vol.20 No.1

Most nations have enacted a law and designated a protective zone of cultural assets in order to preserve them. However, todays protective zone of the cultural assets is for only the cultural assets, and is limited to preserve a wide range, for example, protecting the environment around them. In other to cope with the limit, each city has operated a committee of the cultural assets. this study has an object to show the status of the circumstance change around the cultural assets, and propose the deliberating problem, and the improvement on this matter, reviewing the related legislations, the conference reports, and deliberation reports on the subject of 8 areas applying the state change in Kyunggi province from 1998 to 2000. First, the application of the circumstance change is for a building, a graveyard, and a site of a castle, types applied from a middle-civic district, a middle-agricultural district, and a greenbelt zone. Second, in the condition of approval and disapproval, approval conditions are the height amendment of a building and security of the distance between things. Third, regarding the deliberation problem and the improvement proposal of the circumstance change, the step of pro-deliberation and deliberation is separated each in order to solve the problem of scenery destruction.

냉기치료후 슬관절강내의 온도변화

백승석,최기섭,박시복,이상건,김영호,양길태,장윤희 大韓再活醫學會 1998 Annals of Rehabilitation Medicine Vol.22 No.2

집쥐에 의한 슴새 번식성공률 감소

남기백,유승화,김동원,유정칠 경희대학교 한국조류연구소 2002 연구보고 Vol.8 No.1

본 조사는 2001년 6월 25일부터 30일, 8월 12일부터 17일, 10월 20~25일까지 제주도 북제주군 추자면에 위치한 사수도에서 집단 번식하는 슴새의 번식성공률을 조사하였다. 현재 사수도에는 약 4000쌍 정도의 슴새가 번식을 하는 것으로 조사되었다. 총 110개의 둥지를 관찰한 결과, 부화률은 약 15%로 나타났으며, 전체 번식성공률은 약 3%로 나타났다. 전체 번식실패률은 96.4%로 나타났으며, 번식실패 요인으로 집쥐에 의한 포식이 92.5%로 가장 높게 나타났다. 또한 포란기와 부화기에 포식률이 각각 42%, 36%로 육추기의 포식률(11%)보다 높게 나타났다. The rate of breeding success of Streaked Shearwaters (Calonectris leucomelas) was studied at Sasu-islet, in chuja-do, cheju island during 25-30 June, 12-17 August, 20-25 October 2001. The breeding population of Streaked Shearwaters at Sasu-islet is estimated to be about 4,000 pairs. This study was based on detailed observations of 110 nests dispersed over a wide range of nest habitats within colony. Hatching success was 15% (n=17), breeding success was 3% (n=3) and breeding failure was 96% (n=106). Norway Rat(Rattus norvegicus) were responsible for failure of at least 89% of all the breeding failure. The predation rates of both incubation and hatiching periods was higher than that of rearing period.

Indoor 채널 환경에서 FH/MFSK 시스템의 성능 분석

이승대,백주기 남서울대학교 공학연구센터 1999 공학연구 Vol.1 No.-

This paper evaluates an analytical derivation of the probability of FH/MFSK signals transmitted through a indoor radio communication channel. In addition, an analytical expression for error probability of a FH/MFSK system due to number of users is numerically derived. The channel model used in the analysis includes the combined effects of the line-of-sight component and lognormal component as a attenuation due to the man-made structure and multipath component. The results show that it is difficult to communicate in an average, heavy shadowing and fading environment, and that the average SNR margin is required about 25 dB in light shadowing and fading. Also, it is found that SNR degrades about 1.3 dB when users increase.

급성 포름알데히드 가스 흡입에 의한 흰쥐 후각상피의 형태학적 변화

백선용,전재기,문용석,황승영,노환중,고의경,왕수건 대한해부학회 1998 Anatomy & Cell Biology Vol.31 No.3

임상교정 교육용 멀티미디어 데이터베이스 웹서버 구축에 관한 연구

박재우,이종기,장영일,남동석,김명기,양원식,김태우,백승학 대한치과교정학회 2000 대한치과교정학회지 Vol.30 No.2

본 연구는 인터넷상의 가상공간에 다양한 자료로 구성된 환자 증례를 통해, 교정을 배우고자 하는 임상의나 학생들의 교육에 필요한 멀티미디어 데이터베이스를 구축하기 위한 것이다. 이러한 시스템을 구현하기 위해서는 이미지 자료의 처리, computer network를 통한 빠른 정보처리 기능, 진단 분석법의 개발, 데이터베이스의 구축 기술, 데이터베이스와 인터넷과의 연계, 증례를 통한 교육방법론과 같은 기술적 문제점들이 있다. 진단과 치료계획을 위한 분석은 모델 분석과 두부방사선 사진분석으로 나누어 제공하였다. 모델분석법은 arch length discrepancy와 Bolton tooth ratio를 환자 정보란에 제공하였다. 두부방사선 사진분석은 초진란에 제공하였다. Cephalometric analysis ver 2.0과 Power Ceph pro 3.3.5를 이용하여 Tweed, Steiner, Jarabak분석법 등을 제공하였으나, 본문에서는 주로 Kim's analysis와 몇 가지 계측치를 추가하여 설명하였고, 나머지는 tracing란에서 제시하였다. 또한 치료 종료 후나 보정란에서 치료 전, 후의 두부방사선 사진을 중첩해서 보여줌으로써 치료에 의한 효과를 직접 볼 수 있도록 하였다. The Objective of this research was to construct the multimedia database system that was necessary for the education of the practitioners and the students. To establish this system, there were technical problems as follows : 1) The processing of the images, 2) The rapid processing of the information with the computer network, 3) The development of diagnosis tools, 4) The technique to establish the database system, 5) The link between the database system and the internet, and 6) The method to educate through many cases. The analysis for diagnosis and treatment planning were provided as two parts : model analysis and cephalometric analysis. As a model analysis, arch length discrepancy and Bolton tooth ratio were provided for the part of patient information. Cephalometric analyses were provided in the part of initial diagnosis. The Cephalometric analysis ver 2.0 and the PowerCeph pro 3.3.5 were used to show Tweed, Steiner and Jarabak analysis. In the main part, Kim's analysis and some measurements were added. In the post-treatment or retention part, we show the superimposition of the cephalometrics with which you can find the effectiveness of the various orthodontic treatment. The address of this home page is "http://damis.snu.ac.kr/orthodontics"

Inconel 718 상향 엔드밀링시 절삭력에 미치는 공구형상오차의 영향

이영문,양승한,장승일,백승기,김선일,이동식 한국공작기계학회 2002 한국생산제조학회지 Vol.11 No.5

In an end milling process, the undeformed chip section and cutting forces vary periodically with the phase change of the tool. However, the real undeformed chip section area deviates from the geometrically ideal one owing to the cutter runout and tool shape error. In the current study, a method of estimating the real undeformed chip section area which reflects the cutter runout and tool shape error is presented during up-end milling processes of Inconel 718. The specific cutting forces, K_r and K_t are defined as the radial and tangential cutting forces divided by the modified chip section area, respectively. Both of the K_r and K_t values become smaller as the helix angle increases from 30˚ to 40˚. Whereas they become larger as the helix angle increases from 40˚ to 50˚. The K_r and K_t values show a tendency to decrease with increase of the modified chip section area.

신생검증례에 의한 사구체신질환의 분석

최두환,구시선,배승훈,박병현,안선호,송주흥 圓光大學校 醫科學硏究所 1996 圓光醫科學 Vol.12 No.2

To elucidate the incidences and the clinical characteristics of glomerular diseases in our hospital, we reviewed the clinical records and histological findings of the 117 cases, which were diagnosed as one of the glomerular disease in renal biospy for about 6 years since 1991. In these 117 cases, 74 cases (63.2 %) fell into primary glomerulonephritis(GN), 18 cases (15.4%) into secondary GN, 2 cases (1.7 %) into end stage kidney, 4 cases (3.4%) into tubulointerstitial disease and the biopsy samples were inadequate for diagnosis in 19 cases. In primary glomerular diseases, most common pathologic diagnosis was IgA nephropathy (36.5 %}, followed by minimal change nephrotic syndrome (29.7%). The incidence of IgA nephropathy would be increased if we had biopsied every asymptomatic urinary abnormality (AUA) patients. Systemic lupus erythematosus (SLE) . hepatitis B accounted for most of secondary GN in our cases. One case of progressive scleroderma was included in this secondary GN. Minimal change nephrotic syndrome (22 cases) was the most common cause of nephrotic syndrome, followed by membranous GN (9 cases) and IgA nephropathy (8 cases). 2 cases of primary amyloidosis were presented with nephrotic syndrome. Nephrotic syndrome as presenting symptom in our IgA nephropathy patients was higher than in other studies, which may be due to indication bias for renal biopsy. We suggest that renal biopsy should be done in adult nephrotic syndrome and in SLE, because various kind of glomerular diseases can develop nephrotic syndrome in adult, renal biopsy can affect the treatment and prognosis in each patients and renal biopsy also determines the extent of renal involvement in SLE on which the treatment depends. In AUA urinary patients, renal biopsy could be reserved for the patients who show declining of GFR or rising of proteinuria. Because IgA nephropathy account for most of AUA. and there is no specific treatment for IgA nephropathy, and renal biopsy in those cases is helpful in ruling out the patients who need no treatment.

한국산 독말풀에 대한연구(Ⅰ) : HPLC에 의한 Hyoscyamine 과 Scopolamine의 정량

도경삼,신민교,송호준,선중기,손인경,백승화 원광대학교기초자연과학연구소 1992 基礎科學硏究誌 Vol.11 No.3

A new method for quantitative determination of Hyoscyamine and Scopolamine in Datura stramonium L. by High Performance Liquid Chromatography(HPLC) was established. A reversed-phase system with a μ Bondapak C18 column using methanol in 0.2% aqueous phosphoric acid(40:60) with PIC A as a mobile phase was developed. Hyoscyamine and Scopolamine were detected at 254nm and the analysis was successfully carried out within 20min.