• Transactions on Electrical and Electronic Materials
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• 제18권6호
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• pp.338-340
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• 2017

Breakdown of solid insulating materials in power equipment could result in undesired outages and replacements, and may be due to an increase in electric stress on the material. Therefore, it is necessary to conduct a proper diagnosis of materials before their practical use. In this work, a few inherent properties of different non-cellulosic insulating materials, such as Nomex, Teflon, laminated Nomex, glass bonded mica, epoxy resin bonded mica paper, and epoxy resin bonded fiberglass, have been evaluated by performing non-destructive dielectric diagnostic measurements, and an attempt has been made to correlate these basic parameters to evaluate the breakdown strength (BDS). An equation has been proposed using a basic theory which defines the correlation between the BDS, dielectric constant, dissipation factor, sample thickness, and volume resistivity. The results obtained from the equation are also compared with the experimental values. The suggested equation will be helpful to predict the BDS of any non-cellulosic material without experimentation in the laboratory.

• 펄프종이기술
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• 제42권5호
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• pp.62-66
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• 2010

Cellulosic materials were dissolved by NMMO(N-methylmorpholine-N-oxide) and CED (Cupriethylene diamine), respectively, to measure their DPs (degrees of polymerization) by using viscometer. We changed cellulose DPs by applying various amounts of low intensity electron-beam radiation to the cellulosic materials. NMMO is environmental-friendly, non-toxic, and biodegradable organic cellulose solvent and used industrially because of its high cellulose dissolving power and high solvent recovery ratio. The cellulose DP measurement results using these two different chemicals were correlated highly ($R^2$ >0.95). It was also found that cellulose with high DP was dissolved more easily in NMMO than CED. In addition, NMMO method gave more higher resolution in the measurement.

• 한국식품저장유통학회지
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• 제5권4호
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• pp.350-354
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• 1998

대추의 연화현상을 연구하고자 건조중에 세포벽 구성성분의 변화를 조사하였다. 알코올 불용성 물질, 세포벽 및 수용성 물질의 함량은 건조 6일까지는 변화가 없었으나 건조 9일째에는 알코올 불용성 물질과 세포벽은 감소하였으나 수용성 물질은 증가하였다. 펙틴질과 헤미셀룰로오스는 건조 6일까지는 거의 변화가 없었으나 건조 P일째에는 펙틴질과 알칼리 가용성 헤미셀룰로오스가 감소한 반면 산가용성 헤미셀룰로오스는 증가하였다. 셀룰로오스는 건조 중에 증가하였다. 수용성 펙틴질은 건조 6일째까지는 뚜렷한 변화가 없었으나 건조 9일째에 현저히 증가하였다. EDTA-soluble 펙틴, 불용성 펙틴, 총 펙틴의 함량은 건조 6일째 이후에 감소하였다. 세포벽의 비섬유성 중성당은 건조 6일째까지는 뚜렷한 변화가 없었으나 arabinose와 galactose의 함량은 건조 9일에 감소하였다. 총 비섬유성 중성당도 건조 6일까지는 변화가 없었으나 9일째에는 뚜렷이 감소하였다.

• 한국태양에너지학회 논문집
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• 제28권4호
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• pp.10-16
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• 2008

The fire resistance of thermal insulation and interior finishing materials is recently much emphasized after the fire accident at the Icheon Cold Store in January 2008. Three kinds of thermal insulation are used in buildings. They are Organic, Non-organic and cellulosic insulation. Organic insulation such as polystyrene foam board and urethane foam has high thermal resistance but it has no fire resistance. While non-organic insulation such as rockwool and glassfiber has high fire resistance, it has lower thermal resistance than organic insulation. Cellulose insulation is primarily manufactured from recycled newsprint or cardboard using shredders and fiberizers. Despite of its environmental friendliness and high thermal resistivity, its domestic use has not much increased because of the prejudice that paper can easily burn. However, the cellulose insulation as a product is about 80 wt.% cellulosic fiber and 20 wt.% chemicals, most of which are fire retardants such as boric acid and ammonium sulfate. It is required to secure its fire safety for more consumption as a building insulation in Korea. Therefore, this study investigates the fire resistance of Korean cellulose insulation according to the rate of fire retardant and finally presents the optimum rate of fire retardant in cellulose as building insulation. The fire safety test was conducted according to the ASTM C 1485-00. The test results indicate that above 18 wt% of fire retardant is necessary to secure the fire safety of cellulose insulation.

• 한국의류학회지
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• 제30권7호
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• pp.1025-1033
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• 2006

Kenaf bast can be obtained by decortication of Kenaf stem. Kenaf fibers are much more rough than cotton fiber because they include impurities as pectin, lignin and hemicellulose besides cellulose. The purpose of this research is to investigate the distribution of kenaf fiber length and diameter during the processes of removing impurities. To remove pectin, kenaf bast was retted chemically. A half of the retted kenaf fiber bundle were scoured and bleached. The other half one were treated with $NaClO_2$ solution to remove lignin, and were treated with sodium hydroxide solution to remove hemicellulose. Four kinds of specimens that were obtained for investigating physical characteristics. Length and diameter of 100 fibers on each specimen was measured. The tensile strength of 100 fiber bundles were measured. And also the color values of them were measured with spectrocolorimeter. The length of retted kenaf fiber was 16.97cm. Then it decreased to 11.43cm after bleaching. Kenaf fiber bundles could be finer by chemical processes that remove non-cellulosic materials. The thickness of retted fiber was $132{\mu}m$. And after undergoing the chemical processes to remove non-cellulosic materials, the thickness of kenaf fiber became finer as $73{\mu}m$. Tensile strength of the retted kenaf fiber bundles was 11.37Mpa. The retted kenaf fiber lost their strength as 22.6% by bleaching and as 18.3% by treatment for removing lignin. The retted kenaf fiber showed low whiteness as 56.48 of L*value. After bleaching, the kenaf fibers have creamy white color and their whiteness got 90.02 of L*value. After the treatment for removing hemicellulose, the kenaf fibers also have creamy white color and their whiteness got L* value of 79.02.

• 한국식품저장유통학회지
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• 제8권1호
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• pp.66-73
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• 2001

본 연구에서는 복숭아 '미백도', '대구보' 및 '유명' 과실의 발육단계별로 과실의 경도, 세포벽성분 및 g1ycisidase 활성의 변화를 조사함으로써 수확후의 저장중 과실에서와 같이 발육중인 과실의 연화에서 도 $\beta$-galactosidase가 중요한 역할을 하는지 알고자 하였다. 조사시기는 5월 13일, 6월 16일, 7월 16일, 8월 5일이었으며, 수확기가 늦은 '유명'은 8월 28일에 한번 더 조사하였다. Total sugar와 비섬유성 중성당의 함량은 각 품종의 세포벽물질을 증류수, 0.05M CDTA 0.05M $Na_2$CO$_3$, 4% KOH, 2.4% KOH로 차례로 분획하여 조사하였다. 과실의 발육에 따라 경도는 세 품종 모두에서 감소하였으며, '유명' 과실의 경도는 모든 발육단계에서 '미백도'와 '대구보'보다 높았다. 발육단계에 따른 각 분획별 total sugar의 함량 변화는 품종간에 뚜렷한 차이가 없었다. 세 품종의 세포벽 물질과 각 분획중의 주요 중성당은 arabinose와 galactose였다. '미백도'와 '대구보'의 수확일인 8월 5일의 증류수 가용성 분획의 rhamnose의 mol % 변화는 품종별 경도 변화와 상관관계가 있었다. 가용성 $\beta$-galactosidase의 활성은 세 품종 모두에서 파실 발육초기에는 높았으나 초기 이후에는 매우 낮은 수준이었다. 세포벽결합형 $\beta$-galactosidase는 세 품종 모두에서 발육초기에 높았던 활성이 수확기가지 계속적으로 감소하였다. 다른 glycosidase의 활성들도 품종간에 뚜렷한 차이를 보이지는 않았다.

• 생명과학회지
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• 제16권5호
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• pp.834-839
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• 2006

'쓰가루' 사과의 연화동안에 일어나는 세포벽 성분의 변화와 펙틴 및 중성당류의 가용화와 분해 정도를 조사하였다. 과실의 연화단계별로 펙틴다당류들을 증류수, 0.05 M CDTA, 0.05 M $Na_2CO_3$, 8 M KOH를 이용하여 분획하였다. Uronic acid (UA) 함량은 과실의 연화가 진행되면서 증류수 가용성 분획에서는 저장 4주후에 급격히 증가하였다. 각 분획별 비섬유성 중성당의 종류를 보면 증류수, 0.05 M CDTA 및 0.05 M $Na_2CO_3$ 가용성분획에서의 주요 구성당은 galactose와 arabinose였으며, 8 M KOH 가용성분획에서는 glucose, galactose 및 xylose였다. 특히 증류수 가용성 분획에서 과실의 연화가 진행되면서 galactose의 함량이 증가되었다. 그리고 증류수 가용성인 물질을 Sepharose CL-2B를 이용하여 uronic acid polymers (UAP)와 carbohydrate polymers (CP)를 분획한 결과를 보면 고분자의 UAP 및 CP가 수확후 과실의 연화가 진행될수록 저분자화 되었다. 고분자 중합물의 양은 과실이 연화됨에 따라 감소하였다.

• 펄프종이기술
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• 제45권1호
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• pp.75-82
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• 2013

The traditional Hanji-making was confronted with lots of industrial disadvantages and economic problems, due to the original hand-made process. Recently, the studies on the automation of overall Hanji manufacturing process is carried out by applying the commercial chemical pulping method in order to expand industrial application or efficiency of non-wood fibrous materials. However, the application of commercial pulping methods to the bast tissues of paper mulberry leads to the chemical and mechanical deterioration of cellulosic fibers. In this study, the optimal cooking method using the bast parts of paper mulberry produced by an auto-scraping device was applied to minimize the damage of fiber strength for the paper yarn manufacture. The pre-steaming treatment and alkaline pulping systems were evaluated in removal efficiency of lignin and pectin materials within the bast tissue of paper mulberry. With the application of pre-steaming treatment and 2 stage pulping system using potassium carbonate and then sodium hydroxide, kappa values were decreased two times more in lignin removal than the single stage of pulping method. It was also identified from SEM images and ATR-FTIR spectra that the pectin components within cellular structure of bast tissue were easily removed and the debarked bast parts by a auto-scraping device were easily defiberized by 2-stage pulping sequence using potassium carbonate/sodium hydroxide pulping system.

• 한국식품과학회지
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• 제41권3호
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• pp.345-349
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• 2009

더덕의 육질과 껍질의 부위별 세포벽 물질(CWM)로부터 uronic acid, 총 당, 비섬유성 중성당, 페놀성 화합물 함량 및 항산화 활성을 측정하였다. 더덕의 육질과 껍질의 uronic acid와 중성당의 비는 4, 6이었다. 총 당 함량은 육질과 껍질에서 각각 788.6, 824.9 ${mu}g/g$ CWM이었다. 주요 비섬유성 중성당은 galactose와 arabinose였다. 더덕 CWM으로부터 분석된 주요 페놀성 화합물은 vanillic acid, p-OH-benzaldehyde, vanillin, ferulic acid 및 8-O-4' diferulic acid 였다. 이들 중 p-OH-benzaldehyde, vanillin, 8-O-4' diferulic acid는 더덕에서 처음으로 동정된 것으로 인삼의 세포벽 페놀성 화합물 조성과 유사하였다. 더덕의 껍질 AIR에 함유된 8-O-4' diferulic acid의 함량은 56.1 ${mu}g/g$ CWM이었다. 더덕의 CWM로부터 얻은 ethanol 분획, ethanol 분획의 ethanol-NaOH 분획, ethanol 분획 후 잔사로부터 얻은 AIR 분획의 항산화 활성의 크기는 ethanol-NaOH 분획이 가장 높았으며, 다음으로 AIR 분획, ethanol 분획의 순으로 나타났다.