Al(III) 응집제의 염기도에 따른 총인 제거효율의 변화

한승우,이철희,이재관,강임석,Han, Seung-Woo,Lee, Chul-Hee,Lee, Jae-Kwan,Kang, Lim-Seok 대한상하수도학회 2012 상하수도학회지 Vol.26 No.2

염기도를 달리하여 제조된 PACl에 대한 Al(III)종 분포는 염기도가 높을수록 monomeric Al(III)종은 적어지고, precipitate Al(III)종은 증가하는 것으로 나타났다. 염기도 13.6%의 경우에서는 monomeric Al(III)종이 81%, polymeric Al(III)종이 19%, precipitate Al(III)종은 0%로 monomeric Al(III)종이 주종을 이루고 있었다. 염기도 13.6%의 경우에서 재안정화 없이 80% 정도의 탁도제거 효율을 유지하고 있었으며, $UV_{254}$ 제거효율이 향상되는 것은 낮은 응집 pH 범위에서 유기물 응집효과가 우수하게 나타나기 때문으로 판단된다. 그리고 13.6% 염기도를 가진 PACl이 T-P 제거효율 및 $PO_{4}-P$의 제거효율이 가장 우수한 것으로 나타났으며 이는 높은 monomeric Al 성분에 기인하리라 판단된다. The analysis of Al (III) hydrolysis species with PACls prepared by different basicity showed that mononmeric Al species were reduced while precipitate Al species were increased with an increase in basicity for PACls. In the case of the PACl with 13.6% basicity, monomeric Al species were 81%, polymeric Al (III) species 19%, precipitate Al (III) species was 0%, as showing the dominant monomeric Al species. The PACl with 13.6% basicity showed above 80% of turbidity removal efficiency without any restabilization. In addition, the PACl with 13.6% basicity showed higher organic removal expressed by $UV_{254}$ which was caused by lower coagulation pH. The PACl containing the higher amount of monomeric Al species was the most beneficial for T-P and $PO_{4}-P$ removal.

가토 악하선 도관 결찰과 절단 후 악하선 세포의 증식에 관한 전자 현미경 및 면역조직화학적 연구

한승우,김경욱,이재훈,Han, Seung-Woo,Kim, Kyung-Wook,Lee, Jae-Hoon 대한악안면성형재건외과학회 1998 Maxillofacial Plastic Reconstructive Surgery Vol.20 No.4

Obstructive sialadenitis of major salivary glands is a common entity that occurs either in sialolithiasis or in foreign-body obstruction of the excretory ducts. This is characterized histologically by the presence of duct-like structural groups in a highly fibrotic stroma. Although the pathologic features are well recognized, the various cell types involved in the atrophy and subsequent regeneration of the obstructed salivary gland have been controversial. For this reason, an animal model of obstructive sialadenitis that induced atrophy in the salivary gland was used. Experimental study was performed to observe changes of submandibular gland in rabbit and apply the results to clinical activity. Forty-five rabbits each weighing about 3Kg were used and divided into control and experimental group. In the experimental group, ducts of submandibular gland was ligated and cutted divided into each twenty rabbits. Rabbits were serially sacrificed on the 3rd, 5th, 14th, 30th day of experiment. The submandibular glands were dissected out at sacrifice and stained with H&E, MT, immunohistochemical stain and the histological examinations were carried out under the light and transmission electron microscope. After examination and comparison of all specimens, the results of this study were as follows: 1. In the features of H&E stain, moderate infiltration of inflammatory cell were present at 3rd day of experiment. The features of ductal metaplasia was observed after 7th day in the ligation group and destructive changes was continued. In the cutting group, atrophic changes were less severe than ligation group but the small ductule were separated from stroma after 7th day. 2. In the feature of MT stain, apposition of connective tissue was increased in all group, more active in ligation group. 3. In the features of immunohistochemical stain, ligation group showed increased PCNA positive response at 7th day and the higher activity of duct cells was observed. Severance group showed more PCNA positive response than ligation group at 30th day. 4. In TEM features, ductal metaplasia was started at 7th day and degenerative change with margination of nucleus had been severe. Although ductal metaplasia was seen in the severance group, more numerous granule in different size was founded than ligation group. From above results, degenerative change was identified with ductal metaplasia, apically apposition of granule, r-ER destruction in ligation group. Severance of duct elicit degenerative change of grandular cells but the change was less severe than ligation group and more PCNA positive cell was founded at acinar cell.

하수처리수의 인 제거에 미치는 Al(III) 응집제 염기도의 영향

한승우(Seung Woo Han),이철희(Chul Hee Lee),이재관(Jae Hwan Lee),강임석(Lim Seok Kang) 大韓環境工學會 2012 대한환경공학회지 Vol.34 No.3

다양한 염기도를 가진 PAC 응집제를 이용한 응집실험에서, 염기도를 낮게 함유하고 있는 PACB (Polymeric Aluminum Chloride Basicity)의 경우 염기도가 높은 PAC 보다 유기물과 인에 응집효율이 높게 나타났다. 저 염기도의 PACB는 고 염기도의 PAC보다 monomeric Al(III) 가수분해 종을 많이 함유하였다. 하수처리수의 응집에 있어서 전하중화와 sweep floc 형성에 따른 응집효율은 저 염기도의 PACB가 고 염기도의 PAC에 비하여 다소 효과적인 것으로 나타났다. 이에 따라 PACB와 PAC를 이용한 응집실험 결과 Al₂O₃ 농도가 유사한 경우 고 염기도의 PAC에 비하여 저 염기도 PACB가 탁도, CODMn 그리고 TP 및 PO₄-P에 대하여 보다 우수한 응집효과를 나타내었다. According to the coagulation tests for PACs with various basicities, the PACB with lower basicity showed higher coagulation efficiencies of organics and phosphorus than the PAC with higher basicity. The PACB contained higher amount of monomeric Al (III) hydrolytic species comparing with PAC. In case of the coagulation for the sewage treated water, the coagulation efficiency by the charge neutralization and sweep floc formation was higher with PACB than with PAC. Accordingly, when Al₂O₃ concentration was similar in the coagulant, PACB showed higher removal efficiencies of turbidity, CODMn, TP, and PO₄-P comparing with PAC, especially in the lower range of coagulant dose.

코로나19 이후 대학 온라인 교육에 관한 학습자들의 반응 조사 연구

한승우(Han, Seung-Woo),김보영(Kim, Bo-young) 한국문화융합학회 2020 문화와 융합 Vol.42 No.10

본 연구는 ‘자발적’ 온라인 수업과 ‘비자발적’ 온라인 수업에 대한 학습자들의 만족도를 비교하고, 유형별 온라인 수업(동영상 및 ZOOM)에 관한 만족도를 함께 조사하여 제시하고 있다. ‘자발적’으로 온라인 수업에 참여한 학생들이 ‘비자발적’으로 온라인 수업에 참여한 학생들에 비해 자기주도학습, 학습몰입, 만족도, 학습지속의향 모두에서 더 높은 평균값을 보였다. 즉 자발적으로 참여한 학생들이 비자발적으로 참여한 학생들보다 만족도와 학습효과가 더 높게 나타난 것이다. 또한, 셀프 스튜디오와 ZOOM 수업 모두에서 ‘학습지속의향’이 전반적으로 높게 나타났으며, 그 중에서도 ZOOM 수업이 더욱 높은 수치를 보였다. 학습자들이 온라인 수업에 대해 비교적 높은 호응과 만족도를 가지고 있는 것으로 보이는 대목이다. 동영상 강의는 반복해서 듣는 데 효과적인 것으로 나타났으며, ZOOM은 온라인 수업에서 소통을 가능하게 하는 장점을 증명하였다. 온라인 수업과 대면 수업이 결합할 경우, 이러한 결과를 반영하여 효과적인 수업 방안을 모색할 수 있을 것으로 본다. 팬데믹 이후의 대학 교육에는 많은 변화가 올 것으로 예상된다. 그러나 절차 없는 변화에는 많은 혼란과 시행착오의 위험이 도사리고 있다. 학습자들의 의사를 수렴하고, 그것을 충분히 반영하여 혼합형 수업 방안을 모색해야 한다. 대면 수업이 긴 세월을 통해 노하우를 축적해 왔듯이, 이제 새롭게 도입되는 온라인 수업 역시 많은 시간을 두고 단계별 변화를 이루어가야 할 것이다. This study conducted a survey on the satisfaction level of learners regarding “non-voluntary” and “voluntary” online classes, and their satisfaction level regarding online class (video and zoom) among the many current methods of online class. Students who participated in online classes voluntarily showed higher average values in all of the self-directed learning, learning commitment, satisfaction, and willingness to continue learning than students who participated in non-voluntary online classes. This means that students who participated voluntarily showed higher satisfaction and learning effect than students who participated involuntarily. In addition, in both self-studio and ZOOM classes, the “will to continue learning” was generally high and, among them, the ZOOM class showed a higher number. This is the point on which the learners seemed to have relatively high response and satisfaction toward online classes. Video lectures were found to be effective in listening repeatedly, and ZOOM stood out in terms of enabling communication in the online classes. If online classes are applied in face-to-face classes, it is expected that effective class plans can be developed based on these results. It is expected that much change will enter university education after the pandemic. However, there is much confusion and risk of trial and error in change without procedure. It is necessary to collect the various opinions of learners and fully reflect them to seek a hybrid class plan. Just as face-to-face classes have accumulated know-how over the years, the newly introduced online classes will also take time to make gradual changes.

ISDG를 이용한 박막의 인장시험 장치 개발 및 물성 평가

한승우(Seung Woo Han),이상주(Sang Joo Lee),오충석(Chung Seog Oh),안현균(Hyun Gyun Ahn),좌성훈(Sung-Hoon Choa),이학주(Hak Joo Lee) Korean Society for Precision Engineering 2005 한국정밀공학회지 Vol.22 No.12

수처리용 Fe(III)계 응집제의 특성 및 응집특성 비교

한승우(Seung Woo Han),강임석(Lim Seok Kang) 大韓環境工學會 2016 대한환경공학회지 Vol.38 No.4

수처리용 응집제로서 미리 가수분해시켜 고분자성 Fe(III)의 이용과 제조에 대한 연구에서, Ferron 분석법을 통해 Fe(III) 응집제내에 함유된 가수분해종을 정량화하고 그 차이를 살펴보았다. 제조된 PICl (polymeric iron chloride) 중에서 r=1.5의 경우에서 가장 많은 20%의 고분자성 Fe(III)종을 함유하고 있는 것으로 나타났다. 응집 실험은 r 값에 따라 제조된 응집제를 이용하여 응집제 주입량과 응집 pH의 조건을 달리하여 수행하였다. FeCl₃ (r=0.0)와 PICl (r=0.5, 1.0, 1.5)를 이용한 응집 특성 비교에서, PICl (r=0.5, 1.0, 1.5)에서 FeCl₃ (r=0.0) 보다 유기물 제거에 효과적인 것으로 나타났다. 응집 pH에 따른 응집 실험에서도 PICl의 경우에서 pH에 대한 영향이 적게 나타났으며, 폭 넓은 응집 pH(pH 4-9)에서 탁도와 유기물 제거효율이 높은 것으로 나타났다. This research explored the feasibility of preparing and utilizing preformed polymeric solution of Fe(III) as coagulants for water treatment. The differentiation and quantification of hydrolytic Fe(III) species in coagulant was done by utilizing spectro-photometric method based on the interaction of Fe(III) with Ferron as a complexing agent. The properties of the synthesized polymeric iron chloride (PICl) showed that the quantity of polymeric Fe(III) produced at r=1.5 was 20% of the total iron in solution, as showing maximum contents. Coagulation experiments were conducted under the condition of various coagulant doses and pH for each coagulant prepared. From the comparison of the characterization of coagulation for FeCl₃ (r=0.0) and PICl (r=0.5, 1.0, 1.5) coagulants, PICl (r=0.5, 1.0, 1.5) coagulants was found to be more effective than other coagulant for the removal of organic matters. The experimental results for the coagulation tests at various pH ranges showed that the PICl was least affected by the coagulation pH and PICl was very effective for the removal of turbidity and organic materials over wide pH range (pH 4-9) tested.

PACl 응집제의 특성 및 기타 Al ( 3 ) 계 응집제와의 응집특성 비교

한승우(Seung Woo Han),강임석(Lim Seok Kang) 한국물환경학회 1999 한국물환경학회지 Vol.15 No.3

Various Al(Ⅲ) solutions having different r (OH_(added)/Al) values and chemical species compositions were prepared and physical arid chemical characteristics of PACls solutions were examined. Then, the prepared PACls were compared with other Al(Ⅲ) coagulants for coagulation characteristics in water treatment process. The addition of NaOH to the supersaturated AlCl₃ solutions made it possible to synthesize the different types of PACls useful for water treatment. The result of the analysis by timed spectrophotometer with a color developing reagent (ferron) showed that r (OH_(added)/Al), initial aluminum concentration, and base concentration significantly influenced the hydrolytic compositions of aluminum in PACls, but revealed that Al species distribution of PACls was little affected by the base injection rate ranging from 21.5 ㎖/hr to 60 ㎖/hr. Coagulation test of synthetic water showed that the effect of coagulation pH on turbidity removal was severer for low r ratio PACls, alum, and AlCl₃. Also, the effect of pH for coagulation of Nakdong river water showed that each Al(Ⅲ) coagulant had different effects on turbidity and TOC removal. Especially, PACls were least affected among other Al(Ⅲ) coagulants used.

FPGA 기반 AES 암호화 알고리즘 검증 시스템 설계 및 구현

한승우(Seung Woo Han),최훈환(Hun Hwan Choi),강재현(Chae Hyun Kang),공병용(Byeong Yong Ko) 대한전자공학회 2023 대한전자공학회 학술대회 Vol.2023 No.6

SCL Polar Decoder를 위한 간략화된 Bitonic 정렬기의 설계 및 분석

한승우(Seung Woo Han),최훈환(Hun Hwan Choi),강채현(Chae Hyun Kang),공병용(Byeong Yong Kong) 대한전자공학회 2022 대한전자공학회 학술대회 Vol.2022 No.11

In this paper, a simplified bitonic sorter is designed and analyzed for successive cancellation list (SCL) polar decoders. First of all, unnecessary compare-and-swap units (CASUs) are identified and removed based on the relationships between the metrics in the list of SCL decoding. In addition, the CASU depth and the number of CASUs in the proposed sorter are formulated for arbitrary list sizes, and the metrics calculated by the derived formulae are compared with those of the original counterpart. Only 45% of the CASUs in the original bitonic sorter are required to build the proposed sorter.

응집공정을 이용한 하수처리수 중의 인 제거 Mechanism

한승우(Seung Woo Han),강임석(Lim Seok Kang) 大韓環境工學會 2010 대한환경공학회지 Vol.32 No.8

염기도에 따라 제조된 PACl 응집제에 함유된 Al 가수분해종의 분석결과, 염기도 증가에 따라 단분자성 Al종이 감소하고 고분자성 Al종은 증가하였으며, 염기도 2.2에서 가장 많은 고분자성 Al종을 함유하고 있었다. 단분자성 또는 저분자성 Al 가수분해종을 주로 함유하고 있는 alum과 r=0인 PACl에서 인의 제거효율이 가장 높은 것으로 나타나, 효율적인 인의 제거를 위해서는 단분자성이나 저분자성 Al 종을 많이 함유한 응집제가 더 효과적이라고 판단된다. The experimental results for the analysis of aluminum hydrolysis species with PACls (polyaluminum chloride) prepared by different basicity (r value) showed that monomeric Al species were reduced while polymeric Al species were increased with an increase in basicity for PACls. The PACl with 2.2 of r value contained the highest amount of polymeric Al species. According to the experimental results for the phosphorus removal, the alum and PACl (r=0), which consisted of mainly monomeric Al species, were the most effective for phosphorus removal. Therefore, it was concluded that the Al coagulant containing higher amount of monomeric or lower molecular Al species would be more beneficial for phosphorus removal.