• 한국산림과학회지
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• 제97권2호
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• pp.181-186
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• 2008

Even small changes in phosphorus concentrations in stream water could cause eutrophication because of very low level of phosphorus concentrations in natural waters. I investigated the impact of strip cut and clear cut on phosphorus concentrations in stream water at the Hubbard Brook Experimental Forest and investigated stream water phosphorus concentrations as a function of flow rate and season (as well as cutting history). Mean phosphate concentrations in the control (undisturbed forest) increased $1.9{\mu}g\;L^{-1}\;to\;2.6{\mu}g\;L^{-1}$, while strip cut treatment increased phosphate concentrations in stream water $2.2{\mu}g\;L^{-1}\;to\;3.7{\mu}g\;L^{-1}$ during the same period. There was no significant effect of clear cut treatment on phosphate concentrations in stream water. No relationships were found between discharge rate and phosphate concentrations, but the magnitude of fluctuation were increased during two decades in undisturbed forest: $1-5{\mu}g\;L^{-1}$ from 1963 to 1975 and $1-12{\mu}g\;L^{-1}$ from 1983 to 1995. Based on this study, forest harvests with buffer zone will not make a problem by imported phosphate to cause eutrophication in natural water.

• KIEAE Journal
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• 제14권4호
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• pp.35-45
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• 2014

The main objective of this study is to provide an effective algorithm of the transmitted solar radiation calculation through window glazing on a clear day. This algorithm would be used in developing a computer program for fenestration system analysis and shading device design. Various simulation methods have been evaluated to figure out the most accurate and effective procedure in estimation of transmitted solar radiation on a tilted surface on a clear day. Characteristics of simulated results of each step have been scrutinized by comparing them with measured results of the site as well as results from other simulation programs. Generally, the Duffie & Beckman's solar calculation method introducing the HDKR anisotropic model provided the most reliable simulation results. The DOE-2 program usually provided over-estimated simulation results. The estimation of extraterrestrial solar radiation and beam normal radiation were conducted pretty accurately. However, the solar radiation either on horizontal surface or on tilted surface involves complicated factors in estimation. Even though the estimation results were close to the real measured data during summer when solar intensity is getting higher, the estimation provided more error when solar intensities were getting weaker. The convex polygon clipping algorithm with homogeneous coordinates was fastest model in calculation of sunlight to shaded area ratio. It could not be applied because of its shape limitation.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2011년도 춘계학술발표대회 논문집
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• pp.63-67
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• 2011

KnowledgThe Korea Institute of Energy Research(KIER) has begun collecting horizontal global insolation data since May, 1982 at different locations. Because of a poor reliability of existing data, KIER's new data will be extensively used by the solar system users as well as by research institutes. But the quality of solar insolation data is not always good. This reports on an attempt to identify systematic error in such data using clear-day analysis for data rehabilitation. Clear-day analysis is successful in uncovering solar insolation data of questionable quality. It is not proven that rehabilitation process can improve the quality of data for daily or monthly means, but it is suggested that the method can be used to improve the quality of data for monthly means of several years for use in many applications of solar energy plarming. Earlier studies finding a maximum ETR of about 0.80 are confirmed.

• Macromolecular Research
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• 제16권2호
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• pp.108-112
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• 2008

Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) analysis of nonpolar polymeric materials is affected by the sample preparation as well as the matrix and cationizing agent. This study examined the influence of silver salt types on the MALDI analysis of polybutadiene (PB). Silver trifluoroacetate (AgTFA), silver benzoate (AgBz), silver nitrate ($AgNO_3$), and silver p-toluenesulfonate (AgTS) were used as the silver salts to compare the MALDI mass spectra of PB. The mixture solution of PB and 2,5-dihydroxybenzoic acid (DHB), as a matrix dissolved in THF, was spotted on the sample plate and dried. A droplet of the aqueous silver salt solution was placed onto the mixture. The mass spectrum with AgBz showed the clear $[M+Ag]^+$ ion distribution of PB while the mass spectrum with AgTFA did not show $[M+Ag]^+$ ions but only silver cluster ions. The mass spectra with $AgNO_3$ and AgTS did not show a clear $[M+Ag]^+$ ion distribution. The difference in the formation of $[M+Ag]^+$ ions of PB depending on the silver salts was attributed to the silver cation transfer reaction between the silver salt and the matrix (DHB). The mass spectrum showed a clear $[M+Ag]^+$ ion distribution of PB when the conjugate acid of the silver salt was less acidic than the matrix.

• 한국안광학회지
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• 제21권1호
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• pp.11-21
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• 2016

목적: 본 연구에서는 동일재질의 투명 및 써클소프트콘택트렌즈(써클렌즈)를 정상안과 건성안에 착용시켰을 때 착용시간 경과에 따른 눈물막 안정성의 차이를 분석하고자 하였다. 방법: 연구대상자를 눈물량에 따라 정상안과 건성안으로 분류한 후 hilafilcon B 재질과 nelfilcon A 재질의 투명 및 써클렌즈를 각각 착용시키고, 렌즈 착용 30분 후, 6시간 후에 비침입성 눈물막 파괴시간, 렌즈중심안정위치, 눈물막깨짐 시작부위를 측정하여 눈물막 안정성의 변화를 알아보였다. 결과: 정상안과 건성안 모두 투명 및 써클콘택트렌즈 착용 시 착용시간경과에 따라 눈물막파괴시간은 통계적으로 유의한 감소를 보였다. 눈물막깨짐 시작 비율은 두 렌즈 모두 투명렌즈보다 써클렌즈의 주변부에서 높았고, 정상안보다는 건성안의 주변부에서 높게 나타났다. Hilafilcon B 재질보다는 nelfilcon A 재질 렌즈의 주변부에서 눈물막깨짐 시작 비율이 높았으나 착용시간경과에 따른 변화는 서로 다른 양상으로 나타났다. 한편, hilafilcon B 재질의 써클렌즈 착용 시 단위면적 당 눈물막깨짐 개수는 모두 주변부에서 많게 나타났던 반면, nelfilcon A 재질 써클렌즈의 경우는 착용시간 경과에 따라 중심부에서의 수가 증가하였다. 또한, 렌즈중심안정위치는 착용시간 경과에 따라 두 재질 모두 써클렌즈에 비해 투명렌즈가 동공중심 가까이에 존재하였으나 정상안에 비해 건성안의 중심이탈이 크게 나타났다. 결론: 본 연구결과 렌즈착용시간이 경과함에 따라 착색공정을 거친 써클렌즈 뿐만 아니라 투명렌즈도 눈물막에 미치는 영향이 달라질 수 있으며, 렌즈재질에 따라 눈물막 안정성에 영향을 주는 요인 또한 달라짐을 알 수 있었다. 따라서 투명 및 써클렌즈를 착용하고자 할 때에는 착용자의 일일착용시간이나 착용기간 등과 같은 사용습관에 따라 렌즈의 착색공법/염료 뿐만 아니라 렌즈 재질 또한 고려하여 적절한 렌즈를 선택하여야 할 것이다.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2003년도 The Fifth Asian Computational Fluid Dynamics Conference
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• pp.141-142
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• 2003

When the under-expanded supersonic jet impinges on the perpendicular plate, it is well known that the self-induced flow oscillation occurs at the specific conditions. This phenomenon is related with the noise problems of aeronautical and other industrial engineering. But, the very complicated flow field is formed and it is difficult to clear the flow structure and the mechanism of oscillation. This paper aims to clear the characteristics of flow field and the wave pattern during the under-expanded supersonic jet impinges on the plate. The numerical calculation was carried out using the TVD numerical method. In this paper, the flow visualization, the pressure fluctuation on the surface of plate and the mechanism of oscillation are discussed.

• Asian Pacific Journal of Cancer Prevention
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• 제16권1호
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• pp.31-34
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• 2015

While mammography has been used for diagnosis of breast cancer in Kazakhstan for a long period, published data are very limited. Recently stress has been placed on increasing the accuracy by double reading of mammograms. Here we provide an overview of breast cancer screening in the different regions of Kazakhstan with data on the stages of cancers detected. A total 459,816 women aged 50, 52, 54, 56, 58 and 60 years were screened in 2012 and 379,903 in the first 9 months of 2013. Clear differences in levels of detection were noted between urban and rural residents, the latter demonstrating lower rates for both screening and cancer detection. Women aged 50 were more likely to undergo screening than their counterparts aged 60. While there were no clear relationships evident between screening rates and stage or numbers of breast cancers observed, this might be due to a number of complicating factors like geographical variation in risk factors as well as ethnicity. Future analyses should focus on the efficacy of mammography in Kazakhstan to reduce mortality.

• Journal of Korean Society for Atmospheric Environment
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• 제17권E4호
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• pp.145-155
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• 2001

Simple mass balance method was developed to estimate the contribution of two major fugitive dust sources in the Port of Incheon to a nearby residential area in this study. Using the relatively small number of TSP data as well as the data on mass fraction of Fe and organic materials in the sampled dust, our simplified method demonstrated its ability to estimate the contribution of each fugitive source to a specific location including the residential area with relatively reasonable accuracy. It is clear from this simple method can be applied to the situation where two major fugitive dust sources are responsible for the high TSP concentration around the source area and there are clear marker chemicals representing the characteristics of the fugitive dust sources.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 춘계학술대회논문집
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• pp.1161-1168
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• 2002

Vibration and sound characteristics of King Song-Dok Bell are measured and the modal property is investigated. The effect of striking position and modal property on the beat characteristics is examined. It is first found that the beat characteristics are quite different according to the position on the bell surface and clear beat is periodically generated on the circumference. It turns out that in King Song-Dok Bell, striking Dangjwa(the present striking position) makes a beat in the first vibration mode, as well as it produces very clear beat in the second vibration mode.

• 태양에너지
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• 제8권1호
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• pp.107-121
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• 1988

The Korea Institute of Energy and Resources (KIER) has begun collecting horizental insolation data since May, 1982 at different locations. Because of a poor reliability of existing data, KIER's new data will be extensively used by the solar system users as well as by research institutes. But, the quality of the solar radiation data is not always good. This reports on an attempt to identify systematic error in such data using clear-day analysis for data rehabilitation. Clear-day analysis is successful in uncovering solar radiation data of questionable quality. It is not proven that rehabilitation process can improve the quality of data for daily or monthly means but it is suggested that the method can be used to improve the quality of data for monthly means of several years for use in many applications of solar energy planning. Earlier studies finding a maximum ETR of about 0.80 are confirmed.