보로실리케이트 유리의 이온교환에 의한 고강도 투명방탄소재의 제조

김영환,심규인,임재민,최세영,Kim, Young-Hwan,Shim, Gyu-In,Lim, Jae-Min,Choi, Se-Young 한국군사과학기술학회 2010 한국군사과학기술학회지 Vol.13 No.6

Borosilicate glass (81% $SiO_2$-2% $Al_2O_3$-13% $B_2O_3$-4% $Na_2O_3$) was prepared, and the glass was ion exchanged in $KNO_3$ powder containing different temperature and time. The $K^+-Na^+$ ion exchange takes place at the glass surface and creates compressed stress, which raise the mechanical strength of the glass. The depth profile of $Na^+$ and $K^+$ was observed by electron probe micro analyzer. With the increasing heat-treatment time from 0min to 20min, the depth profile was increased from 17.1um to 29.4um, but mechanical properties were decreased. It was also found out that excessive heat treatment brings stress relaxation. The Vickers hardness, Fracture Toughness and bending strength of ion exchanged samples at $570^{\circ}C$ for 10min were $821.8H_v$, $1.3404MPa{\cdot}m^{1/2}$, and 953MPa, which is about 120%, 180%, and 450% higher than parent borosilicate glass, respectively. Transmittance was analyzed by UV-VIS-NIR spectrophotometer. Transmittance of ion exchanged borosilicate glass was decreased slightly at visible-range. It can be expected that transparent bulletproof materials in more light-weight and thinner by ion exchanged borosilicate glass.

고리원전의 온배수 방출이 주변 해조군집에 미치는 영향

김영환,안중관,윤희동,장민아,Kim, Young-Hwan,Ahn, Jung-Kwan,Yoon, Hee-Dong,Jang, Min-A 한국조류학회(藻類) 2007 ALGAE Vol.22 No.4

This study is intended to clarify the effects of heated effluents on intertidal benthic marine algal community in Korea. The species composition and biomass of marine algae at the discharge canal of Gori nuclear power plant on the southeastern coast of Korea were investigated seasonally from February 2001 to October 2006. As a result, 54 species (7 blue-green, 12 green, 9 brown and 26 red algae) of marine algae were found at the discharge canal during the past six years. In general, the number of species observed was abundant during winter to spring and less in autumn. Enteromorpha compressa, E. intestinalis, E. prolifera and Caulacanthus ustulatus were common species found more than 80% frequency during the study period. Seasonal fluctuations of mean biomass were 1-440 g dry wt m?2 and dominant species in biomass were Enteromorpha spp. (contribution to a total biomass proportion 28%), Sargassum horneri (14%) and Amphiroa beauvoisii (14%). It is evident from the floristic composition and biomass data that unique micro-environment of the discharge canal support different communities from those on the intake or control area. Results from the large numbers of surveys before and during plant operation showed that, in the regions influenced by thermal effluents such as the discharge canal of power plants, the process of ecological succession has been proceeded. It is assumed that the uni-directional water flow and the time of overhaul largely affect the development and succession of benthic marine algal communities of the discharge canal.

연구논문 - Properties of Composites - : 주조 A356 Al - SiCp 복합재료의 파괴거동에 대한 공정 Si 입자의 영향

김영환,이성학,김낙준,이두영 ( Young Hwan Kim,Sung Hak Lee,Nack J . Kim,Doo Young Lee ) 대한금속재료학회 ( 구 대한금속학회 ) 1990 재료강도 심포지엄 Vol.- No.-

UO$_{2}$ 펠릿 산화로의 분말 비산 방지를 위한 최종속도 측정

김영환,윤지섭,정재후,진재현,홍동희,Kim Young-Hwan,Yoon Ji-Sup,Jung Jae-Hoo,Jin Jae-Hyun,Hong Dong-Hee 한국방사성폐기물학회 2005 방사성폐기물학회지 Vol.3 No.2

A voloxidizer for a hot cell demonstration, that handles spent fuels of a high radiation level in a limited space should be small and spent fuel powders should not be dispersed out of the equipment involved. In this study a density rate equation as well as the Stokes'equation has been proposed in order to obtain the theoretical terminal velocity of powders. The terminal velocity of U$_{3}$O$_{8}$ has been predicted by using the terminal velocity of SiO$_{2}$, and then determination has been the optimum air flow rate which is able to prevent powders from scattering. An equation which has shown a relationship between theoretical terminal velocities of U$_{3}$O$_{8}$ and SiO$_{2}$ has been derived with the help of the Stokes'equation, and then an experimental verification made for the theoretical Stokes' equation of SiO$_{2}$ by means of an experimental device made of acryl. The theoretical terminal velocity based on the proposed density rate equation has been verified by detecting U$_{3}$O$_{8}$ powders in a filter installed in the mock-up voloxidizer. As the results, the optimum air flow rates seem to be 20 LPM by the Stokes'equation while they are 14.5 L/min by the density rate equation. At the experiments with the mock-up voloxidizer, a trace amount of U$_{3}$O$_{8}$ seems to be detectable at the air flow rate of 14.5 L/min by the density rate equation, but U$_{3}$O$_{8}$ powders of 7$\mu$m diameter seem detectable at the air flow rate of 20 L/min by the Stokes'equation. It is revealed that 14.5 L/min is the optimum air flowe rate which is capable of preventing U$_{3}$O$_{8}$ powders from scattering in the UO$_{2}$ voloxidizer and the proposed density rate equation is proper to calculate the terminal velocity of U$_{3}$O$_{8}$ powders.

동해안 울진원전의 온배수 방출이 주변 해조군집에 미치는 영향

김영환,안중관,이재일,엄희문,Kim, Young-Hwan,Ahn, Jung-Kwan,Lee, Jae-Il,Eum, Hee-Moon 한국조류학회(藻類) 2004 ALGAE Vol.19 No.3

In order to clarify the structure and seasonal dynamics of warm tolerant benthic marine algal community in Korea, the species composition and biomass of marine algae at the discharge canal of Uljin nuclear power plant on the East Coast of Korea were investigated seasonally from February 1992 to October 2000. 107 species of marine algae were found at the discharge canal during the past nine years. In general, the number of species observed was abundant in spring or summer and less in autumn or winter. 27 species (4 blue-green, 5 green, 6 brown and 12 red algae) of marine algae occurred more than 1/ 6 frequency and thus can be categorized as warm tolerant species. Among these, one brown (Dictyota dichotoma) and four red algae (Gelidium amansii, Anphiroa ephedraea, Hydrolithon sargassi, Marginisporum crassissimum) are recorded as warm tolerant marine algae for the first time in Korea. Padina arborescens, Anphiroa zonata and Corallina pilulifera were common species found more than 75% frequency. Seasonal fluctuations of mean biomass were 0-1,330 g dry wt m^(-2) and dominant species in biomass were Corallina pilulifera (contribution to a total biomass proportion 34%), Anphiroa zonata (23%), Padina arborescens (18%) and Sargassum micracanthum (11%). The red algae appeared as predominant algal group at the discharge canal of Uljin nuclear power plant in the qualitative and quantitative aspects. The green algae such as Enterornorpha compressa appeared rather frequently at the discharge canal, but the biomass proportion was very low, in contrast to Kori nuclear power plant where there was definite green algal dominance. Differences in algal communities developed at the discharge canals of Uljin and Kori nuclear power plant on the East Coast of Korea, particularly biomass proportions of green algae, can probably be related to local environmental factors such as water velocity through the canal and natural seawater temperatures.

이전장용여부(耳栓裝用與否)에 따른 난청도(難聽度)의 추이(推移)

김영환,이종영,김두희,Kim, Yeong-Hwan,Lee, Jong-Young,Kim, Doo-Hie 대한예방의학회 1984 예방의학회지 Vol.17 No.1

소음작업(騷音作業) 근로자(勤勞者)들의 이보호구장용(耳保護具裝用)의 여부(與否)에 따른 청력보존(聽力保存)의 효과(效果)를 관찰하기 위해 $16{\sim}24$세(歲)사이의 건강(健康)한 여성(女性) 기직공(機織工) 1,237명을 대상(對象)으로 이전(耳栓)을 장용(裝用)하고 있는 자(者)들을 실험군(實驗群), 하지 않고 있는 자(者)들을 대조군(對照群)으로 하고, 1982년(年) 4월에서 1983년(年) 1월(月)사이에 실시된 특수건강진단(特殊健康診斷) 결과지(結果紙)에서 그들의 근속년수(勤續年數), 4,000Hz에서 AA-30A, RION Japon청력계(聽力計)로 측정된 최소가청치(最小可聽値)를 조사 비교하였다. 최소가청치(最小可聽値) 40 dB초과의 경우는 대조군(對照群)의 좌이(左耳) 44.6% 우이(右耳) 40.9%, 실험군(實驗群)의 좌이(左耳) 8.0% 우이(右耳) 6.6%였고 근속년수(勤續年數)가 길수록 대조군(對照群)과 실험군(實驗群) 모두에서 증가(增加)하였다. 최소가청치(最小可聽値)의 분포(分布)는 좌우이(左右耳)사이에 유의한 차(差)를 실험군(實,驗群)과 대조군(對照群) 모두에서 볼 수 없었으나, 대조군(對照群)과 실험군(實驗群)간에는 좌우이(左右耳) 모두에서 통계적으로 유의한 차(差)를 나타내었다(p<0.005). 대조군(對照群)과 실험군(實驗群)사이에 최소가청치(最小可聽値) 40 dB초과에 속하는 경우의 차이(差異)는 근속년수(勤續年數) 1년이하, 3년, 5년, 5년 초과에 따라 각각 좌이(左耳) 26.8%, 38.0%, 43.3%, 45.4%, 우이(右耳) 29.5%, 31.6%, 38.9%, 36.5%로 증가(增加)하는 경향이었다. To assess the hearing conservation by the hearing protection devices in the field, 1,237 healthy female weavers of 16 to 24 year old were surveyed from April 1982 to January 1983. By reviewing the charts, their working durations, hearing threshold shift levels and whether wearing the ear plugs or not were checked. The hearing threshold levels were measured at 4,000Hz by audiometry AA-30A, RION Japan. They were divided into two groups: an experimental group with ear plug and the control group without it. The threshold shift level above 40dB in controls was 44.6% in left and 40.9% in right ear and that in experimental group 8.0% in left and 6.6% in right ear. The distribution of threshold shift levels between control and experimental group was significantly different in both ears, but that between left and right ear not significantly different in both groups. The longer the working durations were, the more the proportion of high threshold shift levels was and the larger the differences in the proportion of above 40dB between both groups were.

초음파 식품여과 장치의 개발

김영환,전재근 ( Young Hwan Kim,Jae Kun Chun ) 한국산업식품공학회 1997 산업 식품공학 Vol.1 No.1

복합재해 발생 예상 시 지방도로 중심의 재난 레질리언스 평가체계 구축

김영환,전계원,Kim, Young-Hwan,Jun, Kye-Won 한국방재안전학회 2020 한국방재안전학회 논문집 Vol.13 No.4

전 세계적으로 레질리언스의 중요성이 부각되고 있음에도 자연재해와 관련된 레질리언스의 단일정의는 명확하지 않은 실정이다. 그 이유는 레질리언스의 정의가 취약성, 복구, 적응력, 지속가능성과 같은 유사한 용어와 어떻게 관련되어 있는지에 대한 상관성에 대한 구체적인 정의가 없기 때문이다. 또한 국가와 지역마다 지형·지질학적 특성이 다르고 태풍과 가뭄, 지진의 재해종류가 다르듯 이에 대한 각각의 측정지표가 다르기 때문이다. 따라서 본 연구에서는 레질리언스의 정의를 본 연구의 공간적인 특성을 반영하여 '지방도로 또는 인명이나 시설물이 인접해 있는 지방도로에서 발생하는 복합재해(집중호우, 산사태, 토석류)에 대한 복원능력으로 정의하고 이를 도로중심 재난 레질리언스(DRR : Disaster Resilience focusing on the Road)로 구분하였다. 또한 도로중심 재난 레질리언스 인자의 도출을 위해 국내·외 문헌조사를 실시하였고, DRR평가체계 구축을 위한 계층구조 설정 및 AHP설문조사를 실시하였다. AHP설문 분석결과 지방도로 내부에 위치하고 있는 도로재난 직접영향인자(배수시설, 방호시설 등)의 가중치는 0.742로 나타났고, 지방도로 인근에 위치하고 있는 도로재난 간접영향인자(인구, 재산 등)의 가중치는 0.258로 나타나 도로재난 직접영향인자가 간접영향인자보다 상대적으로 높게 분석되었다. Although the importance of resilience is emerging around the world, the single definition of resilience related to natural disasters is not clear. The reason for this is that there is no specific definition of how the definition of resilience relates to similar terms such as vulnerability, recovery, adaptability, and sustainability. In addition, it is because each country and region have different geographic and geological characteristics, and each measurement index is different, just as typhoons, droughts, and earthquakes have different types of disasters. Therefore, in this study, the definition of resilience is reflected in the spatial characteristics of this study as the ability to recover from'complex disasters (concentrated heavy rain, landslides, earth and stone flows) occurring on local roads or on local roads adjacent to people or facilities. Defined. And it was divided into DRR: Disaster Resilience focusing on the Road. In addition, domestic and foreign literature surveys were conducted to derive road-centered disaster resilience factors, and a hierarchical structure was established and AHP survey was conducted to establish a DRR evaluation system. As a result of the analysis of the AHP survey, the weight of direct road disaster influencing factors (drainage facilities, protection facilities, etc.) located inside local roads was 0.742, and the weight of indirect road disaster influencing factors (population, property, etc.) located near local roads. Was found to be 0.258, indicating that the direct impact factor of road disaster was relatively higher than that of the indirect impact factor.

국립공원의 용도지구 설정을 위한 지표인자의 구명

김영환,유기준,신만용 ( Young Hwan Kim,Ki Joon Yoo,Man Yong Shin ) 한국산림과학회 1998 한국산림과학회지 Vol.87 No.3

The objective of this study was to present the proper criteria which could be efficiently used for dividing the land-use zones in Korean national parks. Delphi technique was employed to collect data for this study. The Delphi process was designed with 3 round questionaries for Korean panel experts. A list of 30 criteria was obtained to be considered in dividing land-use zones. From the results, the biological category, in which 10 criteria were involved, occupied the most part of them. This means that the panels consider the biological criteria to be the most important ones under the serious situation of environmental deterioration. Using the 30 criteria emerged from this study, it could be possible to analyze the fitness of the existing land-use zoning system. Prior to the application of these criteria to each park, however, the areal characteristics should be surveyed to select the proper criteria. The new zoning system based on the regional characteristics of each park could be efficiently utilized for management of Korean national parks.

Evaluation of Environmental Circumstance Within Swine and Chicken Houses in South Korea for the Production of Safe and Hygienic Animal Food Products

김영환,서형주,김진만,정연훈,문경환,Kim, Young-Hwan,Suh, Hyung-Joo,Kim, Jin-Man,Jung, Yeon-Hoon,Moon, Kyong-Whan Korean Society for Food Science of Animal Resource 2008 한국축산식품학회지 Vol.28 No.5

This study was undertaken to determine the concentrations of airborne bacteria, fungi, particles, and endotoxin in swine and chicken houses. Six swine buildings and seven chicken houses were randomly selected in southern Gyonggi Province, South Korea. The geometric mean concentrations of airborne bacteria in swine and chicken houses were $2.7{\times}10^5\;CFU/m^3$ and $5.6{\times}10^7\;CFU/m^3$, respectively. The airborne bacteria concentrations in chicken houses were significantly higher than those of swine houses (p<0.05). The geometric mean concentration of airborne fungi in swine houses was $4.9{\times}10^3\;CFU/m^3$, which was higher than the value of $2.1{\times}10^3\;CFU/m^3$ found in chicken houses. The mean concentrations of airborne particles and endotoxin in swine houses were $3.48\;mg/m^3$ and $943.1\;EU/m^3$, and they were $15.43\;mg/m^3$ and $1,430.5\;EU/m^3$ in chicken houses, respectively. A significant difference between swine and chicken houses was found for total dust (p<0.05), but not for endotoxin. In this study, the concentrations of endotoxin in both swine and chicken houses as well as particles in chicken houses were high, and in about 50% of the samples exceeded the worker health safety levels of $614\;EU/m^3$ suggested in previous studies. These results may indicate a considerable respiratory hazard for workers in these environments.