직접 광대전의 대전특성에 관한 실험적 연구

이창선,김용진,김상수,Lee, Chang-Sun,Kim, Yong-Jin,Kim, Sang-Sao 대한기계학회 2000 大韓機械學會論文集B Vol.24 No.6

Photoelectric charging is a very efficient way of charging small particles. This method can be applied to combustion measurement, electrostatic precipitator, metal separation and control of micro-contamination. To understand the photoelectric charging mechanism, particle charging of silver by exposure to ultraviolet is investigated in this study. Average charges and charge distributions are measured at various conditions, using two differential mobility analyzers, a condensation nucleus counter, and an aerosol electrometer. The silver particles are generated in a spark discharge aerosol generator. After that process, the generated particles are charged in the photoelectric charger using low-pressure mercury lamp that emits ultraviolet having wavelength 253.7 nm. The results show that ultra-fine particles are highly charged by the photoelectric charging. The average charges linearly increase with increasing particle size and the charge distribution change with particle size. These results are discussed by comparison with previous experiments and proposed equations. It is assumed that the coefficient of electron emission probability is affected by initial charge. The results also show that the charge distribution of a particle is dependent on initial charge. Single changed particle, uncharged particle and neutralized particle are compared. The differences of charge distribution in each case increase with increasing particle size.

후판압연의 온도분포 예측모델 개발

이창선,이병화,성언식 ( Chang Sun Lee,Byung Hwa Lee,Un Sik Sung ) 대한금속재료학회 1996 압연기술의 현재와 미래 Vol.- No.-

모바일 크러셔 시스템 기술 개발

이창선,이호연,강범준,Chang Sun Lee,Ho Yeon Lee,Beom Jun Kang 유공압건설기계학회 2024 드라이브·컨트롤 Vol.21 No.1

대전된 입자의 영상효과에 의한 필터효율 향상에 관한 실험적 연구

이창선,정해영,김상수,Lee, Chang-Sun,Jeong, Hae-Young,Kim, Sang-Soo 대한기계학회 2000 大韓機械學會論文集B Vol.24 No.6

Filter efficiency of electrically charged particle in uncharged fibrous filter was measured. In previous studies, the effect of charged particle on filter efficiency was investigated but there was difficulty in measuring of image effect that is appeared at the charged small particle. We could easily measure the image effect with charging small particles by photoelectric charging. The spark discharge aerosol generator and a differential mobility analyzer (DMA) were used to generate sub-micron monodisperse particles (${\leq}200$ nm). The generated particles were charged in photoelectric charging process using ultraviolet lamp and electric field. The filter efficiency of the charged particles, classified by another DMA, was measured in filter tester using a condensation nucleus counter (CNC) as function of particle diameter, particle charge and airflow velocity. It is shown that the filter efficiency increases with increasing charge number of the particle and is affected by particle size and flow velocity. Single fiber filter efficiency mainly depends on image force parameter and peclet number. The peclet number was not considered at previous other papers. We propose a modi fied experimental correlation as function of image force parameter and peclet number.

평균과 비율 검정에서 표본 크기와 검정력 계산의 구현

이창선,강희모,심송용,Lee, Chang-Sun,Kang, Hee-Mo,Sim, Song-Yong 한국데이터정보과학회 2012 한국데이터정보과학회지 Vol.23 No.1

많은 조사에서 표본 크기는 유의수준 또는 제1종 오류확률만을 고려하여 결정하였으나 최근에는 다양한 분야를 중심으로 제1종 오류확률뿐만 아니라 제2종 오류확률 또는 검정력을 함께 고려하여 표본 크기를 결정하는 경우가 늘어나고 있다. 이런 경향은 표본을 많이 얻을 수 없는 연구에서 더욱 뚜렸하다. 본 연구에서는 모평균과 모비율에 대한 검정에서 제1종 오류뿐만 아닌 제2종 오류를 고려한 경우 필요한 표본 크기를 결정하는 과정을 살펴보고 이를 웹사이트를 통해 공개하였다. 또한 주어진 표본 크기와 유의수준에 의한 검정력 계산도 함께 공개하였다. There are cases when the sample size is determined based not only on the significance level but also on on the power or type II error. In this paper, we implemented the sample size and the power calculation when both the significance level and power for testing means in normal distributions and proportions in binomial distributions. The implementation is available on a web site. Alternately, we also calculate the power for a given effect size, type I error probability and sample size.

하악 과두골절의 진단 및 치료 후 예후 측정을 위한 이하두정 X-선 계측사진에서의 정상 계측치

이창선(Chang Sun LEE) 대한구강악안면외과학회 1998 대한구강악안면외과학회지 Vol.24 No.1

저자는 하악과두골절의 진단과 예후측정을 위한 예비적인 연구로서 성인 40명을 대상으로 이하두정 X-선 계측사진을 촬영, 분석하여 아래와 같은 결론을 얻었다. 1. 비교적 식별이 용이하면서 과두의 크기와 위치변화를 측정할 수 있는 계측점은 foramen spinosum(FP), condyhlion lateralis(CL), condylion medialis(CM), lateral point(L), midpoint(M), 그리고 pogonion (Pog)등이다. 2. 과두골절의 진단이나 예후측정에 있어서 과두의 회전변위의 진단에는 각도계측 항목 angel between condylar axis and mandibular line을 계측하고 과두의 전, 후방 변위는 L-TSA, 혹은 L-TPA 계측항목을, 그리고 측방변위는 L-MSP 항목을 계측한다. 3. 하악두(condylar head)의 크기 변화를 측정하고자 할 때에는 CM-CL 계측항목을 이용한다. 과두의 수직변위와 과두경의 길이변화, 그리고 관절공간은 이하두정 X-선 계측사진에서는 계측이 불가능하므로 과두골절의 종합적인 예후측정을 위해서는 다른 X-선 사진을 함께 이용한다. 4. 과두의 형태 및 크기차이가 매우 크므로 개개의 증례에 평균치를 적용하여 정량적인 진단 및 예후측정을 하는 것은 신뢰도가 떨어지리라고 생각된다. 따라서 양측성 골절환자의 진단 및 예후측정에 대해서는 또 다른 방법이 강구되어야 할 것이다. 5. 이와 같은 사항을 종합해 볼 때 이하두정 X-선 사진은 편측성 골절환자의 진단 및 예후 측정이나 악교정 수술 전, 후의 과두의 각도 및 위치변화 연구에 비교측정의 방법으로 유용할 것으로 생각된다. This study was performed to apply the submentovertex cephalometric radiograph to mandibular condylar fratures. Because the left and right structures are not overlaped in the submentovertex radiograph, the dimension and position of mandibular condyle can be clearly identified in this view. The subjects consisted of 40 normal adult patients, twenty healthy males and females with no medical and dental histories. Specific angular and linear measurements were made form dach submentovertex radiograph and computerized statistic analysis was carried out. The results were as follows. 1. There was no sexual difference in the angular measurements such as intercondylar angle, angle between condylar axis and mandibular line, and angle between condylar axis and TPA. Though no sexual difference was seen in the linear measurements related to the position of the condyle such as L-TSA, L-TPA, and MSP-Pog, measurements related to the dimension of the condyle such as condylar thickness, condylar width, L-MSP, L-Cpp, MSP-Cpp, and L-Pog were lager in male than female. 2. Statistically, significant difference between right and left values was seen only in the value of condylar width and L-Cpp(p<0.05). But the correlation coefficient of the condylar width between right and left side was very high it could be thougth very useful to compare the left and right side value clinically. 3. In the correlation analysis between left and right side condylar width, L-Cpp, and L-Pog were showed high relation. On the other hand the value of L-TSA was showed low relation. The other measurements were showed relatively high relation. 4. The difference between the maximum and minimum value of each measurement was considerable that the individual variation of measurement was relatively high.

상세 FE해석을 통한 선박충돌 위험도 평가

이창선 ( Lee Chang-sun ),최현호 ( Choi Hyun-ho ),오홍섭 ( Oh Hong-sub ),조효남 ( Cho Hyo-nam ) 한국구조물진단유지관리공학회 2007 한국구조물진단유지관리공학회 학술발표대회 논문집 Vol.11 No.1

In this paper, Annual Frequency of collapse(AP) of bridge pier is estimated through the realistic material modeling and structural modeling based on the description of applied bridge. An analysis of AF is carried out as following the AASHTO Guide Specification(1991) then, barge and small ship collision analysis using detail finite element analysis is carried out with respect to longitudinal and lateral impact assessment in order to verify the safety of bridge pier. Also, reliability index according to estimated failure probability is calculated.

Smart Sampling 기법을 이용한 PSC Box Girder교의 확률적인 안전도 분석

이창선(Lee, Chang Sun),선종완(Sun, Jong Wan),윤만근(Yun, Man Keun),조효남(Cho, Hyo Nam) 한국콘크리트학회 2007 한국콘크리트학회 학술대회 논문집 Vol.2007 No.5

GIS와 통계분석기법을 활용한 제주지역 급경사지재해 예측 및 평가

이창선(Lee Chang Sun),이병걸(Lee Byung Gul),권혁춘(Quan He Chun),고정우(Ko Jung Woo) 대한공간정보학회 2010 한국공간정보학회 학술대회 Vol.2010 No.1

본 연구에서는 급경사지재해 발생구간에 따른 토질특성을 분석하고 통계적분석을 GIS 기법에 적용하여 급경사지재해를 예측해 보고자 하였다. 이를 위하여 사람의 발길이 많은 사라봉, 별도봉 지역과 송악산 지역의 지형 및 토질공학적 사면 붕괴 유발 인자들을 이용하여 로지스틱회귀분석기법을 GIS에 적용한 예측지도를 작성하고 급경사지재해지역을 예측 및 평가해 보고자 하였다.

하악과두골절의 임상적 방사선학적 분류

이창선(Chang Sun Lee),남일우(Il Woo Nam),허민석(Min Seok Heo),박태원(Tae Weon Park) 대한구강악안면외과학회 1994 대한구강악안면외과학회지 Vol.20 No.3

The condylar fractures were accounted for 18-35.5% of mandibular fractures. They were attempted to classify with various methods in the previous clinical study. This study was based on the clinical charts and X-ray films, were pertained to the 163 patients who had the condylar fractures. And condylar fractures were classified with respect to 1) the level of the fracture 2) dislocation at the fracture level 3) position of the condylar head against the articular fossa. Then, the results were verified in regard to the ages, causes and other mandibular fractures to find the correlating factors. The results were as follows 1. The most common trauma, associated with condylar fractures was fall injury and it is especially true in children. 2. While the head and neck fractures showed a tendency to associate with fall injury and to occur in children, the subcondylar fractures were associated with blow injury and occurred in adults. 3. The head and neck fractures exhibited a tendency that fractured head was dislocated and fracture edge was overrided at the medial side. In the subcondylar fractures many cases were preserved the normal condylar position and had a tendency to override laterally. 4. The displacement of condyle against the articular fossa was related to the state of override at the fracture level. The override at the fracture level was related to trauma and location of fracture. 5. Most of the concomitant fractures were occurred at the symphysis, occurred in adults and were related to the subcondylar fractures.