中部地方 客地의 大氣汚染潛在力에 관한 硏究

李鍾範 江原大學校 附設 環境硏究所 1991 環境硏究 Vol.8 No.-

Air pollution potentials of the 7 cities in the central part of Korea were obtained with the mean wind speed within the mixed layer and the mixed layer height calculated by the Jump Model. Seasonal variation of the afternoon mixed layer height in Seoul area shows that low in winter and high in summer. Annual mean of the morning air pollution potential was lowest in Incheon and highest in Wonju. On the other hand annual mean of the afternoon air pollution potential was lowest in Incheon and highest in Chuncheon. Relatively low air pollution potential in Incheon can be explained as high mixed layer height and the effect of sea breeze.

Texas Climatological Model에 의한 短期 大氣汚染濃度 發生頻度의 推定

이종범 江原大學校 附設 環境硏究所 1989 環境硏究 Vol.6 No.-

To estimate the probability of short term concentration of air pollution using ling term arithmetic average concentration, the procedure was developed and added to Texas Climatological Model version 2. In the procedure, such statistical characteristics that frequency distribution of short term concentration may be approximated by a lognormal distribution, were applied. This procedure is capable of estimating not only highest concentration for a variety of averaging times but also concentrations for arbitrary occurrence frequency. Evaluation of the procedure with the results of short term concentrations calculated by Texas Episodic Model version 8 using the meteorological data and emission data in Seoul shows that the procedure estimates concentrations fairly well for wide rage of percentiles.

서울지역의 광화학 오염농도 추정을 위한 중희귀 모델 개발

이선기,이종범 江原大學校 附設 環境硏究所 1991 環境硏究 Vol.8 No.-

The purpose of the study is to develop a multiple regression model for photochemical pollutants in Seoul. Date on daily maximum ozone concentrations measured at 10 air quality monitoring stations in Seoul in case of easterly wind case and westerly wind case were analyzed using principal components analysis. Three orthogonal factors representing ozone area distribution characteristics of each group for wind case were derived using the statistical package, SPSS. These factors accounted for over two-thirds of the distributions at 10 stations. The analysis confirmed that ozone distributions are similar among stations within defined geographical area and depended on wind directions. A stepwise multiple regression procedure was employed to develop the best fit equation relating maximum afternoon ozone concentration to meteorological and pollutant factors. The resulting correlation coefficients for each group were 0.69, 0.58, 0.46 for all wind case, 0.81, 0.85. 0.76 for easterly wind case and 0.78, 0.67, 0.47 for westerly wind case. The multiple regression model could be a potentially useful tool for air pollution forecasters in predicting daily maximum ozone concentrations for each group in Seoul.

PEI계 복합 재료를 이용한 탄자 운반체의 사출 성형 기술 개발에 관한 연구

정태형,이범재,하영욱,이성계 한국공작기계학회 2001 한국공작기계학회 춘계학술대회논문집 Vol.2001 No.-

This research covers the development of new technique for composite injection molding of high stiffness Sabot. An analysis of polymer resin is performed by means of making test specimen mold and doing test with accordance of ASTM test guidelines. Structural analysis and simulation of injection molding process are carried out in order not only to estimate but also to predict the characteristics of molding stresses what both product and structure of mold may have. For structural analysis software, Mold flow and LS-dyna are used and universal test machine is utilized for evaluating performance of sabot. Cases of adopting this material to sabot are not announced yet in domestic academic world. In addition to that, materials for polymer-metal mixed injection molding are imported on the whole due to deficient level of domestic technology. Therefore, this new developed injection molding technique using PEI material can make it available to ensure the technology of making mold, injection and design. Finally, this technique may be applicable to another sabot having different radius of warheads from now on.

정규기상관측자료를 이용한 주간의 현열 플럭스 추정

이종범,김용국,박철용 한국환경과학회 2000 한국환경과학회지 Vol.9 No.2

The purpose of the present study is to develope the estimation scheme for sensible heat flux by semi-empirical approach using routine meteorological data such as solar radiation and air temperature. To compare observed sensible heat flux with estimated sensible heat flux, the sensible heat fluxes were measured by three dimensional sonic anemometer-thermometer. The field observation was performed during 1 year from December 1, 1995 to November 30, 1996 on a rice paddy field in Chunchon basin. The heat fluxes were measured at a heights of 5m and mean meteorological variables were obtained at two levels, 2.5m(or 1.5m) and 10m. Since condition of rice paddy field such as, wetness of the field, roughness length, vary widely, we devided annual data to 5 periods. Comparing with two sensible heat fluxes, the results showed that the correlation coefficients were more than 0.86. Thus, we can conclude that the estimation method of sensible heat fluxes using routine meteorological data is practical and reliable enough.

All-in-one 접착제에서 초음파진동이 법랑질과 상아질의 결합강도와 레진침투에 미치는 영향

이범의,장기택,이상훈,김종철,한세현 大韓小兒齒科學會 2004 大韓小兒齒科學會誌 Vol.31 No.1

초기의 접착 시스템은 여러 단계의 술식을 필요로 하였으며 술자의 기술과 재료의 성질에 크게 좌우되었으나 최근 산부식, priming, adhesive를 한번에 적용할 수 있는 a11-in-one adhesive system이 등장하였다. 치과에서의 vibration의 이용은 치석의 제거 및 접착제의 점도를 낮추는데 이용되어왔으며 vibration은 접착제의 흐름성을 향상시켜 film thickness를 낮추어 수복물 주위의 미세누출을 줄이는데 도움을 준다. 이에 저자들은 all-in-one adhesive system에서 vibration이 법랑질과 상아질의 접착강도와 레진침투에 미치는 효과를 알아보고자 하였다. 법랑질 시편은 발거 후 실온에서 0.1% thymol 용액에서 보관된 30개의 건전한 사람의 대구치를 무작위로 10개씩 세군으로 나누고 근원심 방향으로 두 부분으로 분리하여 각각은 같은 접착제를 사용하고 초음파진동여부를 다르게 하였고, 아크릴 레진을 이용하여 직경 1-inch의 PVC관에 매몰한 후 협설면이 아크릴봉과 동일한 높이가 되도록 220-, 600-grit 연마지로 순차적으로 연마하였고 군당 10개씩 여섯 군으로 분류하였다. 1군과 2군은 Prompt L-Pop(3M-ESPE, Seefeld, Germany), 3군과 4군은 One-Up Bond F(Tokuyama Corp., Tokyo, Japan). 5군과 6군은 AQ bond(Sun Medical Co., Kyoto, Japan)를 제조사의 지시에 따라 도포하였다. 2군, 4군, 6군은 초음파 치석제거기를 이용하여 치면에 대고 15초간 진동을 가한 후 광중합하였다. 상아질 시편은 치관부 법랑질을 제거한 후 상아질면을 아크릴 봉과 동일한 높이가 되도록 하고 법랑질 시편과 동일하게 처리하였다. 이후 직경 2mm, 높이 3mm의 Teflon mold(Ultradent, U.S.A.)를 이용하여 복합레진을 충전한 후 40초씩 두 번에 나누어 광중합한 후 24시간동안 실온에서 증류수에 보관하였다. 열순환 시행한 후, 만능측정 기(Instron4465)로 전단결합강도를 측정하였으며 Resin tag의 양상을 비교하기 위해 각 군의 시편의 치질을 완전히 용해 시킨 후 표면을 주사전자현미경사진으로 관찰하여 다음과 같은 결과를 얻었다. 1. 법랑질에서 초음파 진동을 가한 군(2,4,6군)은 가하지 않은 군(1,3,5군)에 비해 평균 전단결합강도가 높게 나타났다. 그 차이는 AQ bond 군을 제외하고 통계적으로 유의하였다(p<0.05). 2. 상아질에서 초음파 진동을 가한 군(2,4,6군)은 가하지 않은 군(1,3,5군)에 비해 평균 전단결합강도가 높게 나타났다. 그러나 그 차이는 One-Up Bond F군을 제외하고는 통계적으로 유의한 차이가 없었다. 3. 전자 현미경 관찰에서 초음파 진동을 가한 군에서 더 많은 법랑질의 소실과 상아질에서 resin tag의 길이가 길었고 lateral branch의 수도 많이 관찰되었다. The objective of this study was to apply the vibration technique to reduce the viscosity of bonding adhesives and thereby compare the bond strength and resin penetration in enamel and dentin achieved with those gained using the conventional technique and vibration technique. For enamel specimens, thirty teeth were sectioned mesio-distally. Sectioned two parts were assigned to same adhesive system but different treatment(vibration vs non-vibration) Each specimen was embedded in 1-inch inner diameter PVC pipe with a acrylic resin. The buccal and lingual surfaces were placed so that the tooth and the embedding medium were at the same level. The samples were subsequently polished silicon carbide abrasive papers. Each adhesive system was applied according to its manufacture's instruction. Vibration groups were additionally nitrated for 15 seconds before curing. For dentin specimen, except removing the coronal part and placing occlusal surface at the mold level, the remaining procedures were same as enamel specimen. Resin composite(Z250 3M. U.S.A.) was condensed on to the prepared surface in two increments using a mold kit(Ultradent Inc., U.S.A.) Each increments was light cured for 40 seconds. After 24 hours in tap water at room temperature, the specimens were thermocycled for 1000cycles.. Shear bond strengths were measured with a universal testing machine(Instron 4465, England). To investigate infiltration patterns of adhesive materials, the surface of specimens was examined with scanning electron microscope. The results were as follows : 1. In enamel, the mean values of shear bond strengths in vibration groups(group 2,4,6) were greater than those of non-vibration group(group 1,3,5). The differences were statistically significant except AQ bond group. 2. In dentin, the mean values of shear bond strengths in vibration groups(group 2 4, 6) were greater than those of non-vibration groups(group 1,3,5). But the differences were not statistically significant except One-up Bond F group. 3. The vibration group showed more mineral loss in enamel and longer resin tag and greater number of lateral branches in dentin under SEM examination.

한라산 경사면의 일사량 및 기온 추정 모형

이종범,이민영,최재천 江原大學校 附設 環境硏究所 1991 環境硏究 Vol.8 No.-

A prototype air temperature and solar irradiance simulation model was developed to predict the distribution pattern over the slope of Mt. Halla in Chejudo. The model is based on potential effects of major topo-geographical factors on hourly air temperature derived from principal component analysjs multiple regression analysis. Although the model outputs were not validated yet, the precision based on 1km by 1km grid and small RMS error show a feasibility for practical applications to diverse economic activities in Cheju Island.

우리나라 청정지역에서 측정한 PM_(2.5) 입자의 특성

이종훈,김용표,문길주,김희강,정용승,이종범 江原大學校 附設 環境硏究所 1998 環境硏究 Vol.15 No.-

Atmospheric fine particles (PM_(2.5)) were collected at the background sites, Kangwha, Taean, and Kosan and characterized to understand their behaviors at the sites. Daily samples of PM_(2.5) mass were measured and ionic species, carbonaceous species, and gaseous species were analyzed. Four-daγ backward trajectory analysis was also carried out. The mean concentrations of anthropogenic species were highest at Kangwha among three sites, while contributions from sea salts were highest at Taean during the measurement period due to higher wind speed at Taean. Major chemical components in fine particles were sulfates organic carbon, nitrate, and ammonium. Most of the non-sea-salt (nss) sulfates in PM_(2.5) might be present as ammonium sulfates at these sites. Most air parcels arriving at Kangwha and Taean were from northern China. Therefore, both sites were thought to be affected by the same air parcel. At Kosan, during the measurement period, air parcels were from either northern China or southern China. The nss sulfate concentration in the air parcels from southern China was higher, while the nss calcium nitrate, and ammonium concentrations were higher when the air parcels were from northern China.

Pasquill 安定度階級의 評價와 安定度 Parameter 推定方法의 開發

李鍾範,金龍國 江原大學校 附設 環境硏究所 1990 環境硏究 Vol.7 No.-

Pasquill stability class (PSC) was evaluated with Monin-Obukhov length (L) using the data observed at a height of 213m meteorological tower in Tsukuba, Japan. PSC was determined with wind speed and insolation (net radiation at night), and L was calculated with the heat flux and the friction velocity obtained at 25 m by the eddy correlation method. To evaluate PSC with L, for every class of Pasquill stability(from A to F class), percentiles and median of L were used. Results show that for every class of Pasquill stability, L varies so widely that PSC does not adequately represent the atmospheric stability conditions. The scheme which estimates L using air temperature at two levels and wind speed at single level was developed. Comparison between estimated L by the scheme and observed L reveals that the scheme is better than PSC. Furthermore, the scheme is more advantage than PSC because it uses air temperature at two levels instead of insolation shich is more difficult to observe in the ifeld than air temperature.

춘천지역 도시열섬의 특성과 대기질에 미치는 영향

이종범,김용국,김태우 江原大學校 附設 環境硏究所 1994 環境硏究 Vol.11 No.-

An observational study of urban heat is1and was carried out using field data obtained during 6 day in May and August 1992 in Chunchon(Population size 180,000). Air temperature was measured at 04 points along two sampling routes by thermisters attached to cars, Both routes cover urban and rural area and across the center of urban area, Continuous observation of air sonde was performed to clarify heights of nocturnal boundary layer(NBL) at the center of urban area. Surface meteorological observations were performed at both urban and rural site. This study showed that heat island Phenomena was obvious1y observed at the urbanized area during the night time With low wind Speed. The average NBL heights extended to about 100 meters, but varied with meteorological conditions. After sunset the air temperature decreased with time at both sites and cooling rate at the urban site was Heater than the rural site. The maximum heat island intensity was 7.5°C at 21 LST May 4. Using the two meteorological data gets obtained from urban and rural sites, the air Pollutant concentration was calculated by Gaussian plume model which can obtain not only horizontal distribution of concentration but also vertical distribution. The result indicated that the concentration resulted from urban meteorological data set was lower than that from rural meteorological data set. It was also calculated that the air pollutant extended to higher level in urban meteorological data set than that in rural meteorological data set.