• 펄프종이기술
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• 제32권5호
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• pp.60-66
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• 2000

Coating immobilization is the process by which the wet coating applied to paper or paperboard reaches the final form. A coating immobilization point is defined as the solids content reached during drying where no further redistribution of coating materials occurs. Good control of coating immobilization is important in producing coated paper and paperboard with consistent high quality. This paper discusses the technical concepts of how coatings immobilize, and describes the importance of good immobilization control on coating holdout and coating structure. The use of soy protein polymers to modify the coating immobilization point is discussed. Soy proteins, because of their interaction with coating pigments, make a significant contribution to the immobilization characteristics of coastings. This technology gives the formulator options for changing the immobilization point to improve the performance of the coating. The importance of immobilization on casting uniformity, microporosity and sheet qualities is discussed, including binder migration, mottle, gluing, and print quality.

• 펄프종이기술
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• 제32권1호
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• pp.94-100
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• 2000

This study was carried out to understand the present status of the quality evaluation capability of domestic fine paper industry. Six light weight coated papers and one wood containing printing and writing paper with similar basis weights were produced by seven paper companies and their properties were evaluated at four different testing laboratories of domestic fine paper mills. Paper properties including basis weight , thickness , tensile, tear , brightness , opacity, etc were examined , and the repeat ability and reproducibility of the test results were analyzed. Results showed that repeatability of the measurements within the laboratory was satisfactory . Reproducibility of the measurements between laboratories, however, was not satisfactory. This showed that strict implementation of the standard testing methods and periodic calibration of testing equipments should be made to improve quality evaluation capability of domestic fine paper industry.

• 한국축산식품학회지
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• 제43권1호
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• pp.25-45
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• 2023

This study evaluated the antibacterial and antioxidant activities of ethanol extract of calamansi pulp (CPE) and its effect on quality and biogenic amine (BAs) formation in pork patties during storage. The CPE were prepared in various conditions (ethanol concentrations of 50%, 70%, and 90% with extraction periods of 3 and 6 days). The extract with potent antibacterial and antioxidant activities (90%, 6 days) was selected for addition to pork patties. Three groups were tested: Control (without extract addition), CPE addition at 0.2% w/w (0.2PCPE), and 0.4% w/w (0.4PCPE). The addition of CPE inhibited the formation of BAs, mainly cadaverine, histamine, and tyramine, in pork patties during storage. The pH and bacterial count of pork patties decreased significantly in a concentration-dependent manner following the addition of CPE. The instrumental color (CIE L^*, CIE a^*, and CIE b^*) tended to be higher in 0.4PCPE than in the control during storage. The thiobarbituric acid reactive substances and volatile basic nitrogen (VBN) values of pork patties were affected by CPE, showing a reduction toward lipid oxidation at any storage period, and maintaining the lowest VBN value in 0.4PCPE at the final storage day. Similarly, the reduction of total BAs in pork patties was observed ranged between 3.4%-38.1% under treatment with 0.2% CPE, whereas 18.4%-51.4% under 0.4% CPE addition, suggesting significant effect of CPE to improve meat quality. These novel findings demonstrate the efficacy of 0.4% CPE as a natural compound to preserve the quality and reduce BAs formation in pork patties during storage.

• 펄프종이기술
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• 제40권2호
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• pp.57-64
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• 2008

In general, the entire of paper mulberry bark, which is not cut into pieces with an appropriate length, have been used in the pulping. This kind of pulping method couldn't accomplish the improvement of beating and sheet forming efficiency. For this reason, we investigated the effects of the cutting length of paper mulberry bast fiber on pulping and Hanji (Korean traditional paper) properties, in order to develop high quality Hanji manufacturing process. The cutting length variation of paper mulberry white bast did not great effects on pulp yields. The pulp yields based on pulping methods were sulfomethylated pulping av. 57.4%, alkali-hydrogen peroxide pulping av. 55.4%, and alkaline pulping av. 53.5% respectively. The optical properties such as brightness, opacity, scattering coefficient, and absorption coefficient were slightly improved by the increase of paper mulberry white bast cutting length. The increase of paper mulberry white bast cutting length resulted in poor sheet formation. Physical properties such as breaking length, TEA, tear index, burst index, and folding endurance were slightly improved by the increase of cutting length. The modified pulping processes, which used sulfomethylated method and alkali-hydrogen peroxide method, showed better pulp and sheet properties than conventional alkaline pulping.

• 대한소아치과학회지
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• 제26권2호
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• pp.310-316
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• 1999

외상받은 치아에서 치수강폐쇄, 치수괴사, 치근흡수, 인접치조골소실, 치근단염증성변화 및 치아상실 등의 부작용이 나타날 수 있으며, 이는 치근형성정도, 탈구의 종류, 고정의 기간에 따라 예후가 달라진다. 외상후 부작용의 빈도를 줄이기 위해서는 조기에 치수생활력 유무를 판단하는 것이 중요하다. 그러나 미성숙치근을 가진 치아는 치수내 신경발달분포가 불완전하고, 환자의 연령이 어려 술식에 대한 이해력이 부족하고 치과에 대한 공포감 때문에 전기치수검사등의 전통적인 치수생활력 방법의 신뢰도가 떨어진다. 반면 laser Doppler flowmetry는 치수혈류량을 측정하여 치수생활력을 검사하는 방법으로서 보존적이며 객관적이고, 외상후 비교적 조기에 치수생활력을 측정할 수 있는 신뢰도가 높은 치수생활력 검사방법이다. 이에 저자는 외상받은 미성숙치아를 대상으로 냉검사, 전기치수검사, laser Doppler flowmetry를 이용하여 치수생활력을 검사하여 다음과 같은 결과를 얻었다. 1. 외상받은 치아의 치수생활력은 초기에는 음성으로 나타날 수 있으나 시간의 경과에 따라 양성으로 회복될 수 있어 장기간의 관찰이 필요하다. 2. 치수생활력은 냉검사, 전기치수검사 보다 laser Doppler flowmetry 에서 더 빨리 나타났다. 3. 냉검사와 전기치수검사의 두가지 치수생활력 검사방법중 전기치수검사 보다 냉검사가 신뢰도가 더 높았다.

• 펄프종이기술
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• 제38권2호
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• pp.52-60
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• 2006

Environment-friendly shock-absorbing materials were made of wastepaper such as Korean old corrugated containers(KOCC) and Korean old newsprint (KONP) with a vacuum forming method. The plate-like cushioning materials made of KOCC and KONP respectively by vacuum forming showed superior shock-absorbing properties with lower elastic moduli compared to expanded polystyrene (EPS) and pulp mold. Even though the plate-like materials had many free voids in their fiber structure, their apparent densities (${\approx}0.1g/cm^3$) were a little higher than that of EPS (${\approx}0.03g/cm^3$) and much lower than that of pulp mold(${\approx}0.3g/cm^3$). However, the elastic moduli of the cushioning materials made of wastepaper were much lower than that of EPS or pulp mold. This finding implies that the cushioning materials made of KOCC fibers containing more lignin than KONP show better shock-absorbing properties than KONP. Moreover, the cushioning materials made of KOCC and KONP respectively showed greater porosity than pulp mold. The addition of cationic starch to the cushioning materials contributed to the increase in the elastic modulus to the same level as that of EPS. Furthermore, the deterioration in fiber quality by repeated use of wastepaper played a positive role in improving shock-absorbing ability.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2006년도 PAN PACIFIC CONFERENCE vol.1
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• pp.31-36
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• 2006

Tritium has been used to directly measure the exchangeable hydrogen in bleached softwood kraft pulp. The hydrogen atoms associated with hydroxyl groups in pulp or with water contained in the pulp can dissociate and exchange with the hydrogen atoms in bulk water. Tritium is a radioactive isotope of hydrogen and behaves almost identically to it. The distribution of tritium between pulp and water ($k_{pw}$) can be easily measured and becomes an index of the protons available fur hydrogen bonding. Bleached kraft pulp was refined in a PFI mill to a range of freenesses. Tritiated water was added and the amount exchanged measured. There was a slight steady increase in $k_{pw}$ until approximately 300 CSF; $k_{pw}$ then rose sharply between 300 CSF and 100 CSF. This rise appears to correlate with FSP. It is likely that the action of refining on the fiber reaches a threshold at about 300 CSF causing the fiber surface to break open creating exponentially more surface area. This theory is visually confirmed through light microscopy. The slow increase in fibrillation of the fibers above 300 CSF correlates with the increase in $k_{pw}$. Beyond the threshold of 300 CSF a dramatic difference in fibrillation is shown, also corresponding with the large increase in $k_{pw}$. The freeness difference around 300 CSF is small, but the change in fiber properties is extreme within this region. This change in properties could lead to sheet breaks and other disruptions when producing products around the threshold. This study leads to a better understanding of how fiber changes during refining, resulting in a practical benefit of target freeness determination. Presently, freeness is selected based on product quality and on some measure of runnability. Yet, there are other considerations, demonstrated by the extreme change in fiber properties around 300 CSF.

• 펄프종이기술
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• 제33권3호
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• pp.75-83
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• 2001

The potential of oxygen delignification is a powerful tool to reduce detrimental environmental effects. This study was performed to investigate the effect of steam explosion treatment of chemically treated oak wood on oxygen-alkali pulping. Pulp yield during steam explosion treatment by ${Na_2}{O_3}$-NaOH impregnation was higher than the other impregnation chemicals. Also, NaOH extraction at room temperature after steam explosion treatment improved the kappa number from 140~116 to 90~64. Oxygen-alkali pulping of chemical steam explosion treated woods affected to pulp yields. ${Na_2}{O_3}$-NaOH impregnation was very effective to higher carbohydrate yields at same delignification level. Its carbohydrate yield seemed to be highly related to the effluent pH. Oxygen-alkali pulping after steam explosion treatment of ${Na_2}{O_3}$-NaOH impregnated wood was shown that carbohydrate yield was very high because its effluent pH was increase from natural to mild alkali. Even if oxygen bleaching limit the delignification to 50% in order to avoid unacceptable yield and viscosity losses, oxygen-alkali pulping after steam explosion by ${Na_2}{O_3}$-NaOH impregnation was possible to extend the delignification more than 80%. Considering high pulp yield with lower lignin content from steam explosion treated wood, it might be profitable to end the cook at a high kappa number instead of a low kappa number, and continuously apply the oxygen delignification, in order to better quality pulp.

• 펄프종이기술
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• 제38권2호
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• pp.9-15
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• 2006

Neutral sizing is required for linerboard to solve the troubles in strength and process caused by recycled raw materials. AKD sizing efficiency can be influenced by process condition like white water quality, fines retention and so on. Therefore, this study was aimed to evaluate sizing performance of general and fast cure type AKDs using process water obtained from linerboard mill. To evaluate effect of process water quality on AKD sizing, white water was diluted with tap water at the different dilution ratios and UKP slurry was sized using the prepared water. Also, effects of inorganic and organic ion material on sizing were examined. When white water was used for stock forming, UKP sheet showed very low sizing degree. Sizing degree of sheet was increased with increase of dilution ratio because water quality was improved. Especially anionic organic material had a greater influence on AKD sizing than inorganic material. When white water quality was deteriorated, fast cure type AKD showed superior sizing performance to general type AKD.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2001년도 추계학술발표논문집
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• pp.87-94
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• 2001

Scale is agglomerate or thin film compounded of soluble salts in papermaking process. It causes many problems such as closing up pipelines, contaminating wire and felt, decreasing efficiency of additives and paper quality. In this study, physical factors related to forming scale in white water are determinated and optimum conditions are proposed. To control scale, ACP(Acrylacid Copolymer) was synthesized and compared with conventional chemicals such as EDTA, DTPA and STPP.