비틀림을 받는 正四角斷面 棒의 應力擴大係數에 關한 硏究

權在度,黃在錫 嶺南大學校工業技術硏究所 1979 연구보고 Vol.7 No.1

Many papers for stress intensity factor analysis of crack tip have been read recently. And then, the authors suggested the experimental analysis method of mode Ⅲ stress intensity factors by the displacement freezing method utilized membrane analogy and moire out-of-plane method. In this paper, stress intensity factor of square bar with the external boundary crack is measured by using (수식-입력불가)

Film중감지와 Film의 활용에 따른 화질특성의 고찰

권용재,이상모,김순희,김도형,최태균 한국건강관리협회 2000 건협 Report Vol.3 No.-

원공 주위에 생긴 두 비대칭 crack의 응력확대계수에 관한 연구

權在度,蔡泳晳 嶺南大學校府設 基礎科學硏究所 1983 基礎科學硏究 Vol.3 No.-

The stress field in the vicinity of the crack-tip is mainly affected by the stress intensity factor. In the analysis of stress intensity factor, there are many theoretical, numerical and experimental methods that have been proposed by many analysts. In this study, a numerical method using finite element method and photoelastic experimental method are described. Using above mentioned methods, the stress intensity factor for two unsymmetric cracks around a circular hole is evaluated. The results show that New-man's solution for the symmetric cracks using boundary collocation method is applicable to the longer crack for an unsymmetric case.

長期使用 Cr-Mo 綱 劣化材의 疲勞 Crack 進展 Model

權在度 嶺南大學校 工業技術硏究所 1988 연구보고 Vol.16 No.2

The auther have been attempting to establish a proper method for predicting fatigue livess of structures which have been subjected to meterial degradation. In the present paper, the effect of the material degradation on the fatigue crack growth rate in a 2 1/4 Cr-1 Mo steel was inverstigated. The relation between intergranular fracture surface ratio and stress intensity factor range for the degraded steel and recovered one, which was observed on the electron microscope. As the result, the grain size of the fracture surface followed log-normal distriution, and the fatigue crack growth model of the degraded steel was proposed.

有限板의 圓孔에서 發生한 두 Crack의 應力擴大係數에 關한 硏究

權在度 嶺南大學校 工業技術硏究所 1983 연구보고 Vol.11 No.1

A finite plate is subjected to a uniform tensile stress σon the both ends. The plate contains a central hole of radius R, with two cracks, one is perpendicular to the direction of σand the other is inclined to the direction of σ. In this paper, stress intensity factors for the above two cracks were obtained by using photoelastic experimental stress analysis method. As the results. several figures are represented the relation between stress intensity factors and length ratio of crack and inclination angle of crack.

강인한 퍼지 디지털 PI+D 제어 시스템의 설계 및 구현

권태익,이재홍,김승철,설재훈,임영도 동아대학교 정보기술연구소 2001 情報通信硏究所論文誌 Vol.9 No.1

In this paper, Fuzzy Digital PI+D Controller plans for load, noise, plant change, Fuzzy Controller makes use of simple four rule and membership function, and plant used three phase Induction Motor. Characteristic of system compared from experimentation respectively the proposed Control System, Digital PID Control and Digital PI+D Control System.

비틀림을 받는 棒에 生긴 분기 CRACK의 應力擴大係數

權在度 嶺南大學校 工業技術硏究所 1982 연구보고 Vol.10 No.2

It is well known fact that there is an analogous relationship in terms of differential equation between the torsional stress function and membrane displacement. In this paper, this relationship has been applied to the experimental determination of S.I.F. for external branched crack in a circular shaft under pure torsion by membrane analogous method and moire method. As a result, the experimental value of K?? S.I.F. for shaft with external branched crack coincided with theoretical K?? of shaft with external linear crack which is equal to the projective half length of the branched crack.

Pedunculagin(Purified tannin)의 BRM Response

이도익,장재권,이민원,홍순각 중앙대학교 약학연구소 1998 약학 논총 Vol.12 No.-

Pedunculagin, an ellagitannin from Alrus hirsuta var. microphylla, Betulaceae was evaluated on the antitumor activity. To investigate cytotoxicity of pedunculagin on tumor cells, the effect of the substance on three cell lines(P815, Yac-1, B16-F20) was examined. And the result was somewhat different among three cell lines. The growth-rate of P815 was not cut down significantly, but in contrast, the inhibitory activities on Yac-1 and B16-F10 were effective. ED_50s of pedunculagin against P815, Yac-1 and B16-F10 were 12.16, 1.89, 3.30㎍/㎖ respectively.

레이저 용융 적층공정을 이용한 정밀 형상 제작

김재도,전병철,권택열,이영곤,신동훈 한국레이저가공학회 2000 한국레이저가공학회지 Vol.3 No.3

For the direct metal shape processing the powder feed device which is different from the widely used in rapid prototyping. Is developed, The three dimensional object is shaped with the melting metal powder. The developed research has applied to rapid prototyping in ultraprecision for MEMS and medical science fields required of rapid manufacture of complex shape. The goal of this study make 3D model which has precision accuracy. Powder spreading apparatus has been more improved because that the control of powder spread is very important in layer manufacturing. It consists of the vibration motor, nozzle and tube which supplies various metal powder. This apparatus could control the spreading velocity that could control powder spreading thickness. Laser on/off switch was adapted because laser scanning velocity must be preserved constantly to prevent heat transformation of laser overheating. The error between sintered thickness and experimental one occurred by shrinkage in sintering melting process. The problem of heat transformation was solved by On/Off switching system.

평택시 미군기지 주변 주민의 비행기 소음과 청각학적 평가결과의 관련성

정종도,김현주,정재윤,노상철,권호장 大韓産業醫學會 2009 대한직업환경의학회지 Vol.21 No.2

목적: 비행기소음이 청각에 대한 포괄적인 영향을 파악하기 위하여 이명 및 난청과의 관련성을 규명하고자 한다. 또한 변조이음향방사 검사를 통해 비행기소음의 난청에 대한 영향을 객관적으로 파악하고자 하였다. 방법: 연구 대상지역은 평택시에 위치한 두 개의 미군기지(K-55, K-6) 주면 8개 마을로 선정하였고 대조지역은 비행장에서 10 km 이상 떨어진 5개 마을이었다. 연구대상은 전도성 난청자와 순음청력검사에 협조가 불가능한 경우를 제외하고 노출군 492명 , 대조군 200명이었다. 환경소음은 2005년 12월 9일, 노출지역 8개, 대조지역 2개 마을을 동시에 주간 8시간 측정하였다. 구조화된 설문지를 통해 이명 여부와 그 불편감을 조사하였고, 이명 불편감은 구조화된 '이명 불편감 설문지'를 통해 파악한 뒤감정적, 기능적, 재앙화적 측면에서의 점수를 합산하여 산출하였다. 청력평가를 위해 0.5, 1, 2, 3, 4, 6, 8 kHz에 대하여 순음청력검사와 1582, 2003, 3175,4007 Hz에 대하여 번조이음향방사 검사를 시행하였다. 비행기소음의 노출특성 및 혼란변수의 성차를 고려하여 성별층화분석을 했고, 연속변수는 일반선형모델(general linear model)을 사용하여, 범주형 변수는 로지스택 회귀분석을 사용하여 분석하였으며, 보정한 혼란변수는 연령, 교육정도, 스트레스 반응척도, 군대소음, 농업소음, 직업소음이었다. 결과: 이명 증상 호소율은 남성에서 노출군 47.3%, 대조군 27.6%이었고, 여성에서 노출군 50.8%, 대조군 28.5%이었으며, 그 대응비는 남성에서 2.06(95% CI:1.09~3.88), 여성에서 1.97(95% CI: 1.17~3.30)이었다. 이명 불편감 영역별 점수는 남녀 모두에서 감정적, 기능적, 재앙화적 측면에서 노출군이 비노출군보다 유의하게 높았다(p<0.001). 순음청력검사결과 남성에서는 우측 귀 0.5, 1 kHz에서, 여성에서는 좌측 귀 0.5, 1 kHz와 우측 귀 0.5, 1, 2, 3, 4, 6 kHz 주파수 영역에서 노출군의 청력역치가 대조군보다 유의하게 높았다(p<0.05). 변조이음향방사 검사결과, 남성에서는 두 군간에 비정상률의 차이가 없었으나, 여성의 비정상률은 좌측 귀 3175, 4007 kHz 영역에서 각각 1.92(95% CI:1.10~3.36), 2.71 (95% CI: 1.49~4.91), 우측 귀 각각 1.73(95% CI: 1.01~2.99), 1.78(95% CI:1.01~3.15)의 대응비를 보였다. 결론: 연구결과 수십 년간 군 기지의 비행기소음에 노출된 집단에서 이명과 이명 불편감이 대조군보다 유의하게 높았다. 순음청력검사는 노출군이 대조군보다 통계적으로 유의한 청력저하를 보였다. 변조이음향방사 검사는 여성 노출군에서만 대조군보다 통계적으로 유의한 비정상률을 보였다. 이로부터 비행기소음이 이명과 난청 등 삶의 질에 영향을 미치는 건강문제를 유발할 가능성을 확인할 수 있었다. Objective: To investigate the relationship between aircraft noise and the results of audiological evaluation on tinnitus and hearing loss among residents near United States military air-bases in Pyeongtaek city. Methods: Residents (n=492) exposed to aircraft noise were selected from eight villages near U.S. military air-bases (K-55 and K-6) in Pyeongtaek city. Residents (n=200) from five villages located at least 10km away from the air-base were selected for the control group. All participants completed a questionnaire on tinnitus and audiological evaluations included pure tone audiometry (PTA) and distortion Product otoacoustic emissions (DPOAE). Statistical analyses involved a general linear model and multiple logistic regression stratified by gender and data was a쏜usted by age, educational level, stress response index and noise type (i.e. military, agricultural and occupational). Results: The equivalent noise levels (Leq) in the vicinity of the air-field were 73.4~81.5 dB (A). Tinnitus prevalence was 47.3% and odds ratio (OR) was 2.06 (95% confidence interval (CI): 1.09-3.88) among noise-exposed males. Tinnitus prevalence was 50.8% and OR was 1.97(95% CI: 1.17~3.30) among noise-exposed females. Tinnitus handicap scores among exposed group were significantly higher in functional, emotional, and catastrophic subclasses (P<0.001). PTA revealed hearing thresholds among the exposed group of 0.5 and 1 kHz (male right ear), 0.5 and 1 kHz (female left ear) and 0.5, 1, 2, 3, 4 and 6 kHz on female right ear that were significantly higher than those of the unexposed group. No Significant difference in DPOAE was observed among noise-exposed mes. However, significant differences were evident for noise-exposed females at 3175 and 4007 Hz. ORs of right female ears 3175 and 4007 Hz were 1.73(95% CI: 1.01-2.99) and 1.78(95% CI: 1.01-3.15). ORs of left female ears at 3175 Hz and 4007 Hz were 1.92(95% CI: 1.10-3.36) and 2.71(95% CI: 1.49-4.91) Conclusions: Aircraft noise may adversely affect hearing function and tinnitus.