법정 내화슬래브의 내화성능에 관한 실험 연구

여인환,Yeo. In Hwan 한국방재학회 2012 한국방재학회논문집 Vol.12 No.6

본 연구는 현재 법정내화구조로 규정되어 있는 철근콘크리트조, 철골철근콘크리트조 및 철골철망모르타르조 슬래브에 대하여 재하조건에서의 내화성능을 검토함으로써 관련 규정의 분류체계 개선을 위한 자료 구축을 목적으로 하였다. 실험결과를 요약하면 다음과 같다. (1) 피복두께 40 mm의 경우 철근콘크리트조, 철골철근콘크리트조, 철골철망모르타르조의 변형량은 허용기준 대비 40~44%, 피복두께 50 mm의 경우는 34~37%로 유사한 수준의 내화성능을 보이는 것으로 나타나, 동일 피복의 경우 구조형식에 따른 내화성능 차이는 크지 않은 것을 확인하였다. 다만 근소한 차이로 철근콘크리트조, 철골철근콘크리트조, 철골철망모르타르조의 순으로 내화성능이 우수한 것으로 나타났다. (2) 슬래브 피복두께가 10 mm 증가하면 철골철근콘크리트조의 경우 8%, 철골철망모르타르조의 경우는 7%의 내화성능이 향상되는 것으로 나타났다. 이로써 슬래브의 내화성능은 피복두께와 전체 두께에 비례하여 증가하며, 구조형식의 영향은 거의 없는 것을 확인하였다. (3) 슬래브의 차열성능은 구조형식이나 피복두께의 영향보다는 전체 두께가 증가할수록 향상되었다. 하지만 슬래브 두께 200 mm이상에서는 두께가 증가하여도 차열성능에 미치는 영향이 없는 것으로 나타났다. This study aimed to secure the test data for improving the classification scheme of related regulations about fire resistant slabs by testing the structural member of RC, SRC and SWM slabs which legally prescriptived. Test result may be summerised as follows. (1) In the equal thickness condiion of covering, the deflection of specimen of RC, SRC and SWM showed to have equivalent performance at the rate of 40~44% in the case of 40 mm, 34~37% of 50 mm to the proportion of allowed criteria. It can be placed in order, however, RC, SRC and SWM as a view of fire resisting rate. (2) An increase of 10mm cover thickness of slab lead to the fire resisting rate up to 8% and 7% in SRC and SWM, respectively. This showed that the fire resisting rate increases in proportion to the cover and whole thickness, with few influenced by structural type. (3) The insulation performance of slabs improved by increasing whole thickness, with few influenced by structural type or covering thickness, but in the case of over the 200 mm of thickness of slab it was not further improved.

Collateral effect of the COVID-19 pandemic on emergency department visits in Korea

여인환,김종근,( Byunghyuk Yu ),( Kang-suk Seo ),( Jung-bae Park ),( Yeonjoo Cho ),( Jae Young Choe ),( Changho Kim ),( Yun Jeong Kim ),( Dong Eun Lee ),( In Hwan Yeo ),( Won-kee Lee ) 대한응급의학회 2022 대한응급의학회 학술대회초록집 Vol.2022 No.2

스핀 도핑을 이용한 단결정 실리콘 태양전지 확산 공정 최적화

여인환,박주억,김준희,조해성,임동건,Yeo, In Hwan,Park, Ju Eok,Kim, Jun Hee,Cho, Hae Sung,Lim, Donggun 한국전기전자재료학회 2013 전기전자재료학회논문지 Vol.26 No.5

Rapid thermal processing (RTP) abruptly decreases the time required to perform solar cell processes. RTP were used to form emitter of crystalline silicon solar cells. The emitter sheet resistance is studied as a function of time and temperature. The objective of this study is reduction of doping process time with same performance. Emitter difRapid thermal dfusion was carried out by using a spin on doping and a RTP. iffusion was performed in the temperature range of $700{\sim}750^{\circ}C$ for 1m 30s~15 m. Thermal budgets yielded a $50{\Omega}/sq$ emitter using a P509 source. To reduce process time and get high efficiency, rapid thermal diffusion by IR lamp was employed in air atmosphere at $700^{\circ}C$ for 15 m.

팬텀투과계수와 유효조사면 개념을 이용한 종양선량 확인에 관한 연구

김유현,여인환,권수일,Kim, You-Hyun,Yeo, In-Hwan,Kwon, Soo-Il 대한방사선기술학회 2002 방사선기술과학 Vol.25 No.1

The aim of this study Is to develop a simple and fast method which computes in-vivo doses from transmission doses measured doting patient treatment using an ionization chamber. Energy fluence and the dose that reach the chamber positioned behind the patient is modified by three factors: patient attenuation, inverse square attenuation. and scattering. We adopted a straightforward empirical approach using a phantom transmission factor (PTF) which accounts for the contribution from all three factors. It was done as follows. First of all, the phantom transmission factor was measured as a simple ratio of the chamber reading measured with and without a homogeneous phantom in the radiation beam according to various field sizes($r_p$), phantom to chamber distance($d_g$) and phantom thickness($T_p$). Secondly, we used the concept of effective field to the cases with inhomogeneous phantom (patients) and irregular fields. The effective field size is calculated by finding the field size that produces the same value of PTF to that for the irregular field and/or inhomogeneous phantom. The hypothesis is that the presence of inhomogeneity and irregular field can be accommodated to a certain extent by altering the field size. Thirdly, the center dose at the prescription depth can be computed using the new TMR($r_{p,eff}$) and Sp($r_{p,eff}$) from the effective field size. After that, when TMR(d, $r_{p,eff}$) and SP($r_{p,eff}$) are acquired. the tumor dose is as follows. $$D_{center}=D_t/PTF(d_g,\;T_p){\times}(\frac{SCD}{SAD})^2{\times}BSF(r_o){\times}S_p(r_{p,eff}){\times}TMR(d,\;r_{p,eff})$$ To make certain the accuracy of this method, we checked the accuracy for the following four cases; in cases of regular or irregular field size, inhomogeneous material included, any errors made and clinical situation. The errors were within 2.3% for regular field size, 3.0% irregular field size, 2.4% when inhomogeneous material was included in the phantom, 3.8% for 6 MV when the error was made purposely, 4.7% for 10 MV and 1.8% for the measurement of a patient in clinic. It is considered that this methode can make the quality control for dose at the time of radiation therapy because it is non-invasive that makes possible to measure the doses whenever a patient is given a therapy as well as eliminates the problem for entrance or exit dose measurement.

알카리 식각과 반응성 이온 식각을 이용한 결정질 실리콘 2단계 표면 조직화 공정

여인환,박주억,김준희,조해성,임동건,Yeo, In Hwan,Park, Ju Eok,Kim, Jun Hee,Cho, Hae Sung,Lim, Donggun 한국전기전자재료학회 2013 전기전자재료학회논문지 Vol.26 No.2

Lowering surface reflectance of silicon wafer by texturization is one of the most important processes to improve the efficiency of silicon solar cells. Generally, the texturing of crystalline silicon was carried out using alkaline solution. The average reflectance of this method was 11% at the wavelength between 400 and 1,000 nm. In this study, the wafers were first texturing by NaOH solution at $80^{\circ}C$ for 35 min. Then the wafers were texturing by $SF_6$ and $O_2$ plasma in RIE (Reactive Ion Etching). The average reflectance of two step texturing was reduced to below 5% at the wavelength between 400 and 1,000 nm.

재난(위기) 극복형 과학기술 - 국민이 안전한 건축 화재안전 정책

여인환,Yeo, In-Hwan 한국과학기술단체총연합회 2014 과학과 기술 Vol.541 No.-

에어로젤 복합 무기질 블랭킷과 석고보드를 피복한 고강도콘크리트 기둥의 내화성능

여인환,Yeo,In Hwan 한국방재학회 2012 한국방재학회논문집 Vol.12 No.6

본 연구는 에어로젤 복합 무기질 블랭킷과 석고보드를 이용한 고강도콘크리트 기둥 피복시스템 개발 및 그 성능 평가를 목적으로 하였다. ACB(에어로젤 복합 무기질 블랭킷)-FGB(방화석고보드)피복시스템은 기둥 네 모서리 부분의 변형이나 탈락이 없도록 보강되면 구조체의 내화성능을 충분히 확보할 수 있음이 확인됐다. ACB(5 mm)+FGB(15 mm)구성의 20 mm 피복으로 3시간 내화성능이 확보될 수 있음을 확인하였는데, 이 피복시스템은 동등 성능의 기존 석고보드 내화피복의 50-70% 두께 수준이다. This study aimed to develop and evaluate of fire resistant covering systems for HSC(high-strength concrete) column which has mainly constructed with ACB(Aerogel Composite inorganic Blanket) and FGB(Fire protective Gypsum Board). The ACB-FGB fire resistant covering system showed that it clearly secure the fire resistance performance for HSC column when the reinforcing measures had achieved for four cross-sectional edge sides of member and the system is well continued during test period with no significant deformation or seperation. It was checked out the 20 mm thinkness covering system consist of ACB(5 mm)+FGB(15 mm) can have a rating of 3 hour-fire resistance performance adequately; 20 mm thinkness is only 50-70% level of exsisting gypsum board covering systems that can show an equivalent capacity.

해외연구소 소개-IBM왓슨연구소

여인환,Yeo, In-Hwan 한국과학기술단체총연합회 1994 과학과 기술 Vol.27 No.5

화재피해를 입은 철근콘크리트 기둥의 잔존강도 추정 및 내화성능 요인 분석

여인환,Yeo. In Hwan 한국방재학회 2013 한국방재학회논문집 Vol.13 No.6

본 연구에서는 화재피해를 입은 철근콘크리트 기둥을 대상으로 실험 및 해석적 방법에 의해 잔존강도를 추정하고 내화성능에 영향을 미치는 요인을 분석하였다. 철근콘크리트 기둥의 강도저감율과 내화성능 예측을 위해 간편 계산모델인 EN 1992-1-2의 <TEX>$500^{\circ}C$</TEX> 등온선법을 이용하였다. 철근콘크리트 기둥은 순수 축압축력을 받는 것으로 가정하고 표준 내화실험으로부터 얻은 기둥 내부 온도자료를 활용하여 표준화재에 180분간 노출된 철근콘크리트 기둥의 잔존강도율을 산출하였다. 아울러 콘크리트 강도, 피복두께, 단면크기, 잔존 유효단면적 등 철근콘크리트 부재 내화성능 영향요인의 상관관계를 분석하였다. 본 연구를 통해 추정한 철근 콘크리트 기둥의 잔존강도율은 내화성능설계를 위한 계수하중 설정 및 하중비 설정에 중요하게 활용될 수 있을 것으로 사료된다. This study aims to estimate the residual strength by experimental and analytic method and analyze the elements affecting fire resistant performance of reinfored concrete column. For predicting strength reduction rate and fire resistant rate of reinforced concrete column <TEX>$500^{\circ}C$</TEX> isotherm method of EN 1992-1-2, a simplified calculation method, was used. The residual strength rate of reinforced concrete column, which is exposed to standard fire for 180 minute and assumed to bear the pure axial compressive force, was calculated with inner temperature data achieved from fire resistance test results. Further, the analysis of relations of fire resistance rate affecting elements for reinforced concrete member were performed. The residual strength rate of reinforced concrete column estimated in this study may be used as a significant information for establishing fire load factor and load ratio on performance based fire resistant design.

조사문 선량 분포와 Monte Carlo 계산을 이용한 삼차원 선량 재구성에 관한 연구

박달,여인환,김대용,안용찬,허승재,Park, Dal,Yeo, In-Hwan,Kim, Dae-Yong,An, Yong-Chan,Heo, Seung-Jae 한국의학물리학회 2000 의학물리 Vol.11 No.2

본 연구는 선형 가속기에서 나오는 고 에너지 광자빔 조사를 받은 환자 내부의 선량 분포를 조사문 선량 분포로부터 재구성하는 방법을 개발하기 위한 기초 연구로서 삼차원 선량 분포를 재구성하는 방법을 제시하고 이 방법을 전산모사를 통해 평가하였다. 본 연구에서 제안하는 방법은 환자나 팬톰 내부의 임의의 지점에서 흡수된 선량과 그 지점에 대응되는 조사문 선량의 측정 지점에서 흡수된 선량의 차이를 계산하여 측정된 조사문 선량 분포로부터 환자나 팬톰 내부의 선량분포를 얻는 것이다. 선량의 차이는 역제곱법칙과 선형감쇄계수, 그리고 Monte Carlo 프로그램을 이용하여 환자나 팬톰의 CT 정보로부터 계산한 산란선량과 주선량의 비(scatter to primary dose ratio)를 이용하여 계산한다. 이 방법을 시험하기 위해 여러 종류의 균질 혹은 비균질 팬톰의 조사문 선량 분포를 Monte Carlo 전산모사로 계산한 뒤 팬톰 내부의 선량 분포를 재구성하였다. 광자빔은 1.5 MeV의 단일에너지를 사용하였고 Monte Carlo 프로그램은 EGS4를사용하였다. 본 연구의 방법을 사용하여 재구성된 팬톰 내부의 선량 분포와 Monte Carlo로 계산한 팬텀 내부의 선량 분포와 비교하였다. 비교 결과 오차 -4%∼+2% 이내로 일치하였다. 이 방법은 다른 in vivo dosimetry 방법을 대신하여 환자내의 선량분포를 예측하는데 쓰여질 수 있을 것이다. This is a preliminary study for developing the method of the dose reconstruction in the patients, irradiated by mega-voltage photon beams from the linear accelerator, using the transit dose distributions. In this study we present the method of three-dimensional dose reconstruction and evaluate the method by computer simulation. To acquire the dose distributions in the patients (or phantoms) we first calculate the differences between the doses at the arbitrary points in the patients and the doses at the corresponding points where the transit doses are measured. Then, we can get the dose in the patients from the measured transit dose and the calculated value of the difference. The dose differences are calculated by applying the inverse square law and using the linear attenuation coefficient. The scatter to primary dose ratios, which are calculated by the Monte Carlo program using the CT data of the patient (or phantoms), are also used in the calculations. For the evaluation of this method we used various kinds of homogeneous and inhomogeneous phantoms and calculated the transit dose distributions with the Monte Carlo program. From the distributions we reconstructed the dose distributions in the phantom. We used mono-energy Photon beam of 1.5MeV and Monte Carlo program EGS4. The comparison between the dose distributions reconstructed using the method and the distributions calculated by the Monte Carlo program was done. They agreed within errors of -4%∼+2%. This method can be used to predict the dose distributions in the patient