• 상하수도학회지
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• 제37권4호
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• pp.187-202
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• 2023

This study focuses on the application of a new measurement method that quantifies the residual color of filtered water using a spectrocolorimeter after filtering the discolored substances. It was confirmed through the color and turbidity cross-test that the discolored substances cannot be measured effectively with the current legal color and turbidity test method. Therefore, the National Institute of Environmental Research's filter testing method, which involves filtering the sample through 0.45 ㎛ filter and visually inspecting the color, was improved. A membrane filter colorimetry (MFC) method was established by measuring the color difference (ΔE*ab(65)) of the filtered filter using a spectrophotometer and expressing it as filter color unit (FCU). Using the MFC method, the FCU for reference materials such as iron and manganese, as well as field samples, was measured. The results showed a high correlation with turbidity, and the color difference patterns varied depending on the type of reference materials and field samples. This indicates that the MFC method is an effective new measurement method of discolored tap water.

• 대한환경공학회지
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• 제38권2호
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• pp.87-95
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• 2016

탁도는 송 배수 관로의 부식 등에 의해 발생되는 것으로 알려진 'Discolored Water'현상을 수용가의 물 사용자가 인지할 수 있는 주요 지표로서 활용되고 있다. 즉, 'Discolored Water'는 수돗물 사용자가 육안으로 인지할 수 있는 정도의 탁도를 가진 상태로 정의할 수 있으며, 사용자는 수돗물에 존재하는 불특정의 용존 물질보다는 미세한 입자들에 대한 시각적인 인지인 탁도를 통해서 'Discolored Water'를 인식하게 된다. 이에 본 연구에서는 실제 국내 상수도 시스템 내에서 관측된 다항목의 수질데이터(탁도, pH 및 잔류염소)를 대상으로 하여 탁도 이외의 수질데이터들을 예측모형의 설명변수로 설정한 후 데이터 마이닝 기법(data mining)을 통해 기계학습(machine learning)을 수행하여, 상수도 시스템 내에서의 탁도 변화를 예측하는 모형을 수립하고자 하였다. 수집된 수질 데이터를 대상으로 데이터 마이닝 기법인 Decision Tree를 이용해 탁도 예측모형을 구축한 결과 pH 및 잔류염소를 설명변수로 적용한 모형이 가장 높은 예측결과를 나타내었다. 하지만 예측모형들은 peak 관측치에 대해서는 예측오차가 다소 증가하였는데 이를 보완하기 위해 고주파통과필터를 이용한 전처리 과정을 적용하였다. 그 결과 탁도 데이터의 시계열변화 및 peak 관측치에 대한 예측오차가 감소하는 것으로 나타났다.

• 대한치과보존학회:학술대회논문집
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• 대한치과보존학회 2001년도 추계학술대회(제116회) 및 13회 Workshop 제3회 한ㆍ일 치과보존학회 공동학술대회 초록집
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• pp.591.1-591
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• 2001

This study was performed to evaluate internal bleaching effect of various bleaching agent on discolored nonvital teeth. 40 Human teeth were intentionally discolored with erythrocytes of human blood and randomly divided into 4 groups: 10% carbamide peroxide gel (Opalescence, Ultradent, U.S.A.); 15% carbamide peroxide gel; sodium perborate (Duksan pure chemical Co., Korea) with distilled water; sodium perborate with 30% hydrogen peroxide (Duksan pure chemical Co., Korea).(omitted)

• 펄프종이기술
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• 제38권3호
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• pp.61-65
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• 2006

The objective of this study was to find in what color Korean handmade paper(Hanji) is dyed when it is dyed with a pigment extracted from mugworts using different kinds of mordant, and how the paper is discolored and variety of strength under the condition of accelerated aging test. The results of this experiment are as follows. Among mugwort mordants, only ferrous sulfate mordant produced unique khaki color with a slightly lower degree of discoloration, so it is considered to be applicable in dyeing Korean paper. Bright yellow and light green colors were obtained using mugwort but their chroma was too low for actual use. With regard to water used, colors obtained using underground water had high chroma, but when distilled water was used paper was colored in useless light green. Mordant was found to lower the strength of Korean handmade paper, and the lowering of strength was even more serious under the condition of forced deterioration.

• Restorative Dentistry and Endodontics
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• 제27권4호
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• pp.441-447
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• 2002

The bleaching of discolored nonvital teeth is conservative treatment that satisfy the cosmetic desire. The most common method for this treatment, walking bleaching, is using 30% hydrogen peroxide and sodium perborate. Many alternatives are suggested for preventing the external cervical root resorption that is the common complication of the nonvital teeth bleaching with 30% hydrogen peroxide The same extent of oxidation reactions as that resulted by the bleaching with the application of 30% hydrogen peroxide and sodium perborate can also be acquired more safely by materials that contain 10% carbamide peroxide, used primarily for the bleaching of vital teeth. Therefore, this study was performed to evaluate the efficacy of 10% and 15% carbamide peroxide bleaching gel in nonvatal teeth bleaching. The internal bleaching of intentionally discolored teeth was performed in vitro with 10% carbamide peroxide (Group 1), 15% carbamide peroxide (Group 2), mixture of distilled water and sodium perborate (Group 3), and mixture of 30% hydrogen peroxide and sodium perborate (Group 4). The bleaching materials were refreshed following 3, 6, 9 and 12 days. To evaluate the bleaching effect, the color change of the crowns was measured at 1, 2, 3, 4, 7 and 15 days of bleaching using the colorimeter. The results were as follows：1. L$^*$ and $\Delta$E$^*$ values were increased with time in all bleaching agents (p<0.01). 2. There was no significant difference in L$^*$ and $\Delta$E$^*$ value among bleaching agents. 3. $\Delta$E$^*$ value higher than 3 was shown after 3 days of bleaching with 10% carbamide peroxide gel, 1 day with 15% carbamide poroxide gel, 4 days with mixture sodium perborate and distilled water and 4 days with mixture sodium perborate and 30% hydrogen peroride, respectively. These results revealed that the use of 10% and 15% carbamide peroxide bleaching gel in non-vital teeth bleaching is as effective as mixture of distilled water and sodium perborate and mixture of 30% hydrogen peroxide and sodium perborate. Accordingly, carbamide peroxide could be used clinically to bleach discolored non-vital teeth.

• 한국식품과학회지
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• 제34권6호
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• pp.977-983
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• 2002

식용색소 및 공업용 염료의 인공적 착색여부를 조사한 결과, 심황색소, 식용희석황색소, 마리골드색소, 식용황색 4호, 안나토색소, 카로틴색소는 유사한 색으로 착색되었으며 다른 색소는 착색되지 않았다. 물에 의한 추출시험에서는 참조기 색소와 식용색소황색 제4호는 물에서 용출되지 않았다. 착색 후 색소의 물성실험을 한 결과 물 젖은 가제수건이나 휴지로 색소부위 표피를 문지를 경우 참조기 색소는 표면에 전혀 묻어 나오지 않으나 인공적으로 착색된 색소의 경우에는 물에 의해 색이 뚜렷하게 묻어 나왔으며 참조기의 착색 부위 표피를 아세톤으로 추출할 경우 참조기 색소는 아세톤에 옅은 황색용액으로 추출되었다. 또한, 참조기의 색소처럼 물에 용출되지 않도록 염착이 가능한 공업적 합성염료인 반응성 염료와 분산염료의 착색거동에 대해 실험한 결과, 반응성 염료는 조기에 착색되지만 물 젖은 휴지로 착색부위를 문지를 경우 색소가 용출되었고, 아세톤에는 추출되지 않아 참조기 색소와는 쉽게 판별되었으며 분산염료는 염료가 고르게 착색되지 않고 염료가 입자를 형성하며, 물 적신 휴지로 색소부위를 문지를 경우 색소가 용출됨을 알 수 있었다. 카로틴색소(참조기 색소와 구조가 유사한 색소)와 azo염료의 산화 환원 반응에 따른 소색 반응에서는 산화반응에서 azo염료는 sodium percarbonate와 peracetic acid에서는 소색이 되지 않았으나, fenton시약에서는 1시간 후 소색되었고, sodium hypochlorite에서는 바로 소색되었다. 이에 비하여 카로틴색소는 sodium percarbonate 및 fenton시약에서는 소색되지 않았으나, sodium hypochlorite에서는 2시간 후 소색되었고, peracetic acid에서는 바로 소색되었다. 또한, sodium hydrosulfite, sodium carbonate를 사용한 환원반응시험에서는 azo염료는 소색되었으나, 카로틴색소는 소색되지 않았다. 이러한 결과를 통해 두 색소의 특징적 group을 제거할 때 나타나는 소색 결과를 토대로 진품참조기와 모조참조기의 판별에 이용할 수 있을 것으로 사료된다.

• 한국가구학회지
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• 제21권4호
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• pp.284-292
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• 2010

This research was carried out to examine the properties of fancy cherry veneer overlaid on the PF resin bonded Meranti plywood floor, which 2.5% green tea leaf powder was applied in the UV varnishes and the adhesives for scavenging the volatile organic compounds. The results were as follows: 1. The various properties of the treated samples, such as density, moisture content, thickness swelling, bending strength(MOR), adhesion shear strength, surface abrasion, curling, cyclic delamination test with boiling water, boiling property, cold-resistance and heat resistance, acid resistance and alkali resistance, and anti-contamination property showed no significant difference between the properties of the control samples. 2.5% green tea leaf powder treated floor gave a little better results than the control for surface scratch test. 2. In case of QUV and weathering test, no difference between the treated sample and control was found. 3. The floor was discolored by adding 10% green tea leaf powder to UV coating, and the floor was also discolored to light green during by the soaking test. The color of floor was not changed up to 5% addition level.

• 식물병과 농업
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• 제5권1호
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• pp.64-66
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• 1999

Black leg occurred in potato (Solanum tuberosum L.) grown in Pyungchang, Kangwon-Do, Korea. The symptoms began as small water-soaked lesions on stem, and the affected stems discolored black to brown. It became yellow under dry condition. When lower parts of potato were affected in the field, wilting of leaves and desiccation of the stem were developed. The causal organism was isolated from lesions and identified as Erwinia carotovora subsp. atroseptica based on the morphological, physiological and biochemical characteristics. E. carotovora subsp. atroseptica is the first described bacterium which causes black leg in potato in Korea.

• 한국식물병리학회지
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• 제10권4호
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• pp.333-335
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• 1994

In 1991, the leaves and roots brown rot disease of scarlet kafir lily were found in Taejon and Seoul. The symptoms were appeared as dark-brown and water soaked on leaves. The discolored area of the leaves become halo. The roots revealed blight gray and water soaked. The pathogenic bacteria were isolated from the diseased leaves of the scarlet kafir lily were identified as Erwinia cypripedii on the bais of bacterial characteristics. E. cypripedii is first described bacteria which cause the disease on scarlet kafir lily in Korea. Therefore, we would like to propose to the name of scarlet kafir lily disease caused by E. cypripedii as“bacterial brown-rot of scarlet kafir lily”hereafter.

• 한국산학기술학회논문지
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• 제13권1호
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• pp.451-455
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• 2012

2011년 하절기에 안면도 꽃지해수욕장 수질 및 식물플랑크톤을 조사하였다. COD는 때때로 5.0mg/l를 초과하였고 SS는 대체로 40.0mg/l를 초과하였다. DO, pH, 염분 등은 대체로 안정적인 수준이었고 폭우의 영향으로 염분값이 다소 변동하였다. 엽록소 농도와 식물플랑크톤 현존량은 8월에 상대적으로 높은 값을 보였으나 우려되는 녹,적조 현상은 발생하지 않았다. 식물플랑크톤 우점종은 6월과 7월에 다량의 와편모조류가 출현했으나 8월에는 보편적인 규조류 종들이 우점하였다. 대장균군수는 7월보다 8월에 다소 높은 값(>400CFU/100ml)을 보였으나 위생학적으로 문제될 수준은 아니었다.