기판의 표면에너지가 반사경의 산란에 미치는 영향

이범식,유연석,이재철,허덕재,조현주,Lee, Beom-Sik,Yu, Yeon-Serk,Lee, Jae-Cheul,Hur, Deog-Jae,Cho, Hyun-Ju 한국광학회 2007 한국광학회지 Vol.18 No.6

ZERODUR와 용융 석영으로 저산란 반사경을 제작하고 산란 특성을 연구하였다. Bowl feed 법을 이용하여 초연마면인 표면거칠기 0.326 ${\AA}$인 용융 석영 기판과 표면거칠기 0.292 ${\AA}$의 ZERODUR 기판을 얻었다. 이온빔 스퍼터링 방법으로 초연마된 기판 위에 $SiO_2$와 $Ta_2O_5$를 교번으로 22층을 증착하여 다층박막 고반사 거울을 얻었다. 용융 석영 반사경과 ZERODUR 반사경의 산란이 각각 4.6 ppm과 30.9 ppm으로 측정되었으며, 이로부터 산란이 매우 작은 경우 기판의 표면거칠기가 산란을 결정하는 주요 파라미터가 아니라는 것을 알았다. 나아가 반사경의 표면거칠기를 AFM으로 측정한 결과. ZERODUR 반사경이 용융 석영 반사경 보다 박막의 표면거칠기가 2.3배 더 높게 측정 되었다. 이 결과는 기판-박막 경계면에서 박막 형성 초기에 기판의 화학조성 또는 결정방향과 증착물질의 상호관계로 인하여 박막 형성 초기에 표면거칠기가 급격히 나빠져서 발생하는 것으로 유추되었다. SEO 300A으로 접촉각 측정을 하여 Giriflaco-Good-Fowkees-Young 방법으로 표면에너지를 계산하였다. 표면거칠기 0.46 ${\AA}$을 갖는 용융 석영 기판이 표면거칠기 0.31 ${\AA}$을 갖는 ZERODUR 기판보다 접촉각이 더 작고 표면에너지는 크게 나타났다. 이러한 차이가 기판 종류에 따라 박막형성 초기에 표면거칠기를 다르게 하는 한 요인으로 판단되며, 기판의 표면에너지가 높을수록 미려한 박막표면을 얻는 것으로 확인되었다. ZERODUR의 표면에너지 차이를 설명하기 위해 XPS 분석으로 용융 석영은 Si, O로 구성되었고 ZERODUR는 Si, O, Al, Na 그리고 F로 구성되었다는 것을 알 수 있었다. Ultra-low loss ZERODUR and fused silica mirrors were manufactured and their light scattering characteristics were investigated. For this purpose, ZERODUR and fused silica substrates were super-polished by the bowl feed method. The surface roughness were 0.292 ${\AA}$ and 0.326 ${\AA}$ in rms for ZERODUR and fused silica, respectively. To obtain the high reflectivity, 22 thin film layers of $SiO_2$ and $Ta_2O_5$ were deposited by Ion Beam Sputtering. The measured light scattering of ZERODUR and fused silica mirror were 30.9 ppm and 4.6 ppm, respectively. This shows that the substrate surface roughness is not the only parameter which determines the light scattering of the mirror. In order to investigate the mechanism for additional light scattering of the ZERODUR mirror, the surface roughness of the mirror was measured by AFM and was found to be 2.3 times higher than that of the fused silica mirror. It is believed that there is some mismatch at the interface between the substrate and the first thin film layer which leads to the increased mirror surface roughness. To clarify this, the contact angle measurements were performed by SEO 300A, based on the Giriflaco-Good-Fowkes-Young method. The fused silica substrates with 0.46 ${\AA}$ in its physical surface roughness shows lower contact angle than that of the ZERODUR substrate with 0.31 ${\AA}$. This indicates that the thin film surface roughness is determined by not only its surface roughness but also the surface energy of the substrate, which depends on the chemical composition or crystalline orientation of the materials. The surface energy of each substrate was calculated from a contact angle measurement, and it shows that the higher the surface energy of the substrate, the better the surface roughness of the thin film.

내력벽 위치 변경에 따른 공동주택의 중량충격음 변화 특성

이성복(Seong-Bok Lee),천영수(Young-Soo Chun),이범식(Beom-Sik Lee),양홍석(Hong-Seok Yang) 한국소음진동공학회 2016 한국소음진동공학회 학술대회논문집 Vol.2016 No.4

In this study, floor impact vibration and acoustic analysis were performed according to changing the location of bearing wall in apartments constructed as wall-slab structure. Heavy weight floor impact sound as single-number ratings showed maximum difference in 3dB according to the span of living room or boundary condition by changing location of bearing wall. Increasing binding force by bearing wall or decreasing the span of living room has an effect on decreasing vibration acceleration of the concrete slab. Furthermore, decreasing of vibration make radiated floor impact sound reduce, this will be the reason why design of floor plan is important factors from an acoustical point. Based on the results of this study, floor plan that block well heavy weight floor impact sound can be proposed.

연취급 남성 근로자의 혈중 연농도와 혈액 검사치의 관련성

박민주,이동배,변정식,이범식,Park, Min-Ju,Lee, Dong-Bae,Byeon, Jeong-Sik,Lee, Beom-Sik 대한산업보건협회 2002 산업보건 Vol.167 No.-

The Relationship between Blood Examination Values and Blood Lead Levels of Male Lead Workers

섬유보강 콘크리트의 강도와 초기수축 특성

정지용(Jeong, Ji Yong),최지호(Choi, Ji Hoo),장승엽(Jang, Seung Yup),이범식(Lee, Beom Sik),김봉주(Kim, Bong Ju),김진만(Kim, Jin Man) 한국콘크리트학회 2013 한국콘크리트학회 학술대회 논문집 Vol.2013 No.5

분할 완충 바닥구조 바닥충격음 성능 실험연구

양홍석(Hong-Seok Yang),천영수(Young-Soo Chun),이범식(Beom-Sik Lee),이성복(Seong-Bok Lee),김혜란(Hye-Ran Kim) 한국소음진동공학회 2015 한국소음진동공학회 학술대회논문집 Vol.2015 No.10

모 주물공장 근로자의 작업공정별 분진폭로량, 자각증상 및 건강진단판정 비교

이범식,조영채,변정식,김동현,원선혜,김정윤 忠南大學校 環境問題硏究所 1995 環境硏究 Vol.13 No.-

The relationship among dust exposure dose, special health diagnosis results and subjective symptom questionaire survey for 109 casting foundry workers supervised by a local laber office has been studied from august to october 1993. Subjective symptom, dust exposure dose and health examination evaluation of respective working processes have been analized and concluded as follows; 1. Metal fume concentration in melting process measured 3.21±1.46㎎/㎥ is under threshould limit value(TLV;5.0㎎/㎥), casting sand dust measured in molding and desanding process is 5.8 ±3.41㎎/㎥ and 9.69 ±2.64㎎/㎥ which is 3-5 times higher than TLV(2.0㎎/㎥), metal fume, welding fume and metal dust in finishing process measured 9.34 ±1.32, 13.73 ±16.97 and 10.17 ±3.50㎎/㎥ respectively, which are also 2-3 times higher than TLV(5.0㎎/㎥). 2. The complain rate subjective symptoms appeal evaluated for finishing process are 35.9%, 46.2%, 27.2% and 42.2% for eye smptoms, respiractory, skin, general symptom respectively and the rates above express the highest values and the complain rates for melting process are 24.4%, 37.5% and 35.7% for eye smptoms, respiratory and mental system respectively and for molding and desanding it is 24.3%. 3. Perceived occupational disease rate is found 0.9% with are out of 109 worker surveyed who have been exposed in metal fume of finishing process. 4. 33.0% of workers surved are found to require close examination, the worker of hepatopathy suspected are 21.4% which is the highest and 3.7% for circulatory disturbance suspected. 5. The statistically significant variables in general chracteristics that affect health examination evaluation are smoking(P<0.001), respirator put-on (P<0.05) and working career(P<0.05). 6. Cough(P<0.001), "headache"(P<0.05) and "easily skin exchange by slight stimulation" (P<0.05) are statistically significant to the subjective symptom variables affect health examination evaluation.

랫트의 생체내 카드뮴 단독투여 및 카드뮴과 셀레늄 병용투여에 따른 필수원소의 변화

김동현,변정식,조영채,이범식,김광환,김정윤 忠南大學校 環境問題硏究所 1995 環境硏究 Vol.13 No.-

This study was performed to find out the changes of essential elements as Cu, Fe, Zn, and Ca in blood, liver, kidney and testis of rats. The experimental rats were divided into 4 groups that were consisted of control group(groupⅠ), 3.0㎎Cd/kg group(groupⅡ), 3.0㎎Cd +1.0㎎Se/kg group(groupⅢ) and 3.0mgCd+2.5mgSe/kg group(groupⅣ). Each group was intraperitoneal injection with difference dose of cadmium and selenium such as 3.0mgCd/kg, 3.0mgCd+1.0mgSe/kg and 3.0mgCd+2.5mgSe/kg. Rats were killed at the time of 3 day and 28 day, and Cd, Se, Cu, Zn and Ca concentration in several organs were determined by Atomic Absorption Spectrophotometry and inductively Coupled Plasma. Cadmium content in blood, liver, kidney and testis were significantly increased in the Cd alone injection group than Cd mixed with selenium injection groups. But, copper content were not significantly differences in control and each experimental group. Iron content were significantly increased in the Cd alone injection group than others groups. Zinc and calcium content were significantly decreased in the Cd alone injection group than other groups. On the other hand the essential element content in Cd mixed with selenium injection group were almost equaled with those of control group than Cd alone injection group.