• 대한기계학회논문집A
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• 제27권3호
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• pp.450-454
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• 2003

It is important to control the processing conditions to maximize the replication quality of UV-molded microstructure. In the present study, the tip radius anil surface roughness of V-groove structure were measured to quantify the replication quality. UV-curing dose and the applied pressure were experimentally selected as the governing Processing conditions that affect the replication quality of the UV-molded part. Finally. an experimental optimization technique combining central composite design and desirability function approach was used to maximize the replication quality of UV-molded structure.

• 대한환경공학회지
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• 제22권3호
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• pp.505-510
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• 2000

본 연구는 부영양화시 다량 발생하고, 독소생성의 주원인 종으로 알려진 Microcystis aeruginosa의 정수처리 중 응집공정에서 전염소처리의 영향을 조사하였다. Microcystis aeruginosa를 실험실에서 배양하여, $10^5cell/mL$가 되도록 인공시료를 만들었다. 전염소처리의 염소주입량은 각각 0.2, 1.0, 10 mg-Cl/L으로 하였고, 반응시간은 1시간과 1분으로 하였다. 응집 후 모든 시료의 탁도는 응집제를 0.4 mg-Al/L 주입한 후 매우 낮게 나타났으므로 탁도 유발물질은 염소주입량에 의한 영향이 매우 낮은 것으로 나타났다. 염소량이 증가함에 따라 응집 후 잔류알루미늄은 감소하였고, $UV_{254}$는 증가하였다. 적당한 염소농도(1.0 mg-Cl/L)에서는 반응시간이 길어짐에 따라 $UV_{254}$가 증가하였다.

• 한국동물학회지
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• 제27권1호
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• pp.13-24
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• 1984

산개구리의 germ plasm 및 축결정 세포질에 미치는 자외선의 영향을 수량적, 시간적으로 조사하였다. 산개구리 난의 식물극을 수정 후 60분경에 1,600 $ergs/mm^2$이상의 자외선을 조사하였을때 40%이상의 시원생식세포의 수가 감소하였으나, 그 이하의 양에서는 전혀 영향이 없었다. 그러나 1,600 $ergs/mm^2$부터는 시원생식세포 수의 감소 정도는 자외선의 양에 비례하였다. 또 신경관 형성에 전혀 영향을 미치지 않으면서 시원생식세포의 형성을 완전히 억제시키는 자외선의 양은 4,800 $ergs/mm^2$이었다. 이에 4,800 $ergs/mm^2$의 자외선을 수정 후 일정한 시간간격으로 조사하여 germ plasm에 미치는 자외선의 영향을 조사하였다. 그 결과 자외선이 조사된 시기가 이를수록 시원생식세포수의 감소가 크며, 수정후 60분부터 차츰 감소율이 줄어 들다가 3분열 이후에는 자외선의 효과가 거의 없음을 관찰하였다. 또한 시원생식세포와 축형성에 미치는 자외선의 영향을 시기적으로 비교한 결과 산개구리난의 축결정이 다른 무미양서류에서와 같이 수정에서 제1분열 사이의 $0.7\\sim0.8$시기 이전에 이루어지므로 그 이후에는 자외선의 감응도가 급격히 저하되었다. 그러나 germ plasm의 자외선에 대한 감응도는 훨씬 늦게까지 지속되어 8구기에 이르기까지 그 영향이 나타났다.

• Journal of Photoscience
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• 제9권2호
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• pp.154-157
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• 2002

Direct, continuous, and accurate measurements of solar ultraviolet irradiance (290-400 nm: UVR) have been carried out since 1990, by using both band-spectral ultraviolet-B (290-320 nm: UV-B) and ultraviolet-A (320-400 nm: UV-A) radiometers at Tokai University in Hiratsuka, Japan (35$^{\circ}$N, 139$^{\circ}$E). From our observations, the following findings are provided: 1) an increasing trend in solar UV -B from Oct. 1990 to Sept. 2000; 2) a regional comparison of solar UVR in Japan; 3) the distinct characteristics of UV-B and UV-A irradiance, such as diffuse property, daily and seasonal variation; and 4) human body protection against solar UVR. An increasing 10-year trend in global solar UV - B in Hiratsuka corresponded to a decrease in the total ozone amount measured at Tsukuba (36$^{\circ}$N, 140$^{\circ}$E), giving supportive evidence for a direct link between these two parameters. Furthermore, a strong correlation was found between solar UV-B and total ozone amount from results of UVR measurements at four Tokai University monitoring stations dispersed throughout Japan. Additional results revealed different diffuse properties in global solar UV and in global solar total (300-3000 nm: Total) irradiances. For example, in the global UVR, the diffuse component was dominant: about 80 % independent of weather, with more than 60 % of global UV-B, and more than 50% of global UV-A with even a cloudless clear sky. On the other hand, the portion of the diffuse in the global total irradiance was very low, less than 10 % on a cloudless clear day. Daily and seasonal variations of UV -B and UV -A irradiances were found to be quite different, because of the marked dependence of UV -B irradiance on the atmospheric ozone amount. Moreover, UV -B irradiance showed large daily and seasonal variations: the ratio between maximum and minimum irradiances was more than 5. In contrast, the variation in UV-A was small: the ratio between maximum and minimum was less than 2. Three important facts are proposed concerning solar UVR protection of the human body: 1) the personal minimal erythema dose (MED); 2) gender based difference in MED values; and 3) proper colors for UVR protective clothing.

• 상하수도학회지
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• 제12권3호
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• pp.107-117
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• 1998

In order to removal turbidity at high turbidity, this study was carried to evaluate the coagulants(Alum, PACl, PACS) that was suited the characteristics of raw water in water treatment plants and to determinate the optimum method of lime feed. When the optimum coagulant was selected the organic matter removal was also investigated as $UV_{254}$. PACl, lime first feed had the highest turbidity removal efficiency rate as above 99.1% and then $UV_{254}$ removal rate was obtained over than 88.0%. If you had the necessary of the lime feed, among the method of lime feed time interval feed largely was improved than simultaneous feed. Also, lime feed dose had about 1/5 of coagulants dose in case of Alum and PACl, but always PACS should be considerated lime dose.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.1332-1336
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• 2003

An experimental method is presented to maximize the replication quality of UV-molded micro-optical components. It is important to maximize the replication quality, because one can obtain the replicated micro-optical components with desired properties by accurate control of the shape. In the present study, a simple technique to avoid micro-air bubbles was first suggested. The effects of the UV-curing dose and the compression pressure on the replication quality of UV-molded structure were examined experimentally. Finally, as a practical application of the process design method, microlens arrays with diameters between 8 ${\mu}m$ and 96 ${\mu}m$ were fabricated by the present method, and the replication quality and the optical properties of the replicated microlens were measured and analyzed.

• 소성∙가공
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• 제13권3호
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• pp.236-241
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• 2004

UV-molded microlens arrays with high replication quality were fabricated using a parametric design method. It is important to maximize the replication quality, because one can obtain the replicated micro-optical components with desired properties by accurate control of the shape. In the present study, nickel mold inserts for microlens arrays with lenses having diameters between $3\mu\textrm{m}$ and $230\mu\textrm{m}$ were fabricated by electroforming process. An UV-molding system was designed and constructed, a simple technique to avoid micro-air bubbles was first suggested, and the effects of the compression pressure and UV-curing dose on the replication quality of UV-molded microlens arrays with a diameter of $14\mu\textrm{m}$ were examined experimentally. Finally, geometrical and optical properties of the replicated microlens arrays were measured and analyzed.

• Journal of Photoscience
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• 제9권2호
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• pp.454-456
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• 2002

It is important to determine the action spectrum of UV-B radiation contained in the sunlight to estimate the risk of skin cancer. We have investigated action spectra for induction of apoptosis and reproductive cell death in L5178Y cells using the Okazaki Large Spectrograph at NIBB. L5178Y cells were exposed to light at different wavelengths in UV-B or UV-A region. Frequencies of apoptosis induction and reproductive cell death were determined by counting cells with chromatin condensation, and by the colony formation assay, respectively. The measured sensitivity spectra for the two end-points were in very good agreement. Sensitivity decreased steeply with increase of wavelength in UV-B region and remains nearly constant in UV-A region. The action spectra were also slightly steeper than that for the minimum erythematic dose (MED), but very similar to the light absorption spectrum of DNA in UV-B region. On the other hand, the spectra for both endpoints were similar to MED spectrum but not DNA spectrum in the UV-A region. Also different time-course and morphological difference of apoptosis were found between UV-B (long time, fragmentation) and UV-A (short time, shrinkage) region. These results suggest that DNA damage induced by UV-B light triggers apoptosis and reproductive cell death, but other damaged targets (membrane, protein and so on) trigger these effects in UV-A region.

• 대한토목학회논문집
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• 제41권5호
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• pp.505-512
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• 2021

침지형 자외선 살균조의 자외선 강도를 계산하기 위한 3차원 모델을 개발하였으며, 실제 하수처리장에 설치되어있는 개수로형 살균조와 관로형 살균조에 각각 적용하여 수치실험을 실시하였다. 모델링을 통해 계산한 살균조의 평균 자외선 강도는 각각 7.87 mW/cm²와 13.09 mW/cm²로 계산되었다. 자외선 조사 시간을 반영하고, 혼합 불균형, 램프 노화, 온도 및 파울링에 의한 감쇄효과를 고려한 자외선 조사량은 각각 21.1 mJ/cm², 24.8 mJ/cm²로 예측되었는데 이 값은 목표 자외선 조사량인 20 mJ/cm²보다 각각 5 %, 24 % 높은 것으로 예측되었다. 개발한 UV3D 모델을 사용하면 살균조의 조사 시간이나 램프의 출력을 높이지 않고도 수치실험을 통해 평균 자외선 강도가 가장 큰 최적의 램프 위치를 찾을 수 있다. 램프 위치 조정만으로 본 연구에서 적용한 개수로형 살균조와 관로형 살균조의 자외선 조사량은 각각 0.9 %, 0.5 % 향상시킬 수 있다. 개수로형 살균조의 경우 살균조의 체적은 그대로 유지하면서 가로와 세로의 비율을 조정하고, 램프의 위치를 바꾸면 평균 자외선 강도는 현재보다 7.4 % 더 증가한다.

• 한국물환경학회지
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• 제28권1호
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• pp.57-62
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• 2012

In this study, the inactivation efficiency of Mycobacterium marinum was evaluated in buffered water (pH 7) using a low pressure ultraviolet (LP-UV) lamp, ultrasonic (US), and UV/US sequential processes. In the UV alone process, 3 log inactivation of the M. marinum was achieved with a UV dose of $120mJ/cm^2$. However, a tailing phase was later observed because M. marinum has a high tendency for cell aggregation. Even though the M. marinum was not inactivated in the US alone process, the hydrophobicity decreased and turbidity increased due to the crumbling of the cell aggregation. Among the candidate processes which were UV alone, US-UV sequential process and UV-US-UV sequential process, the US-UV sequential process showed the highest synergistic effects for M. marinum inactivation. Consequently, US is a very useful process as a UV irradiation pre-treatment to inactivate M. marinum in water.