• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2000.06a
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• pp.16-23
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• 2000

The increasing functional needs of top-quality printing papers and packaging paperboards, and especially the rapid developments in electronic printing processes and various computer printers during past few years, set new targets and requirements for modern paper quality. Most of these paper grades of today have relatively high filler content, are moderately or heavily calendered , and have many coating layers for the best appearance and performance. In practice, this means that many of the traditional quality assurance methods, mostly designed to measure papers made of pure. native pulp only, can not reliably (or at all) be used to analyze or rank the quality of modern papers. Hence, introduction of new measurement techniques is necessary to assure and further develop the paper quality today and in the future. Paper formation , i.e. small scale (millimeter scale) variation of basis weight, is the most important quality parameter of paper-making due to its influence on practically all the other quality properties of paper. The ideal paper would be completely uniform so that the basis weight of each small point (area) measured would be the same. In practice, of course, this is not possible because there always exists relatively large local variations in paper. However, these small scale basis weight variations are the major reason for many other quality problems, including calender blacking uneven coating result, uneven printing result, etc. The traditionally used visual inspection or optical measurement of the paper does not give us a reliable understanding of the material variations in the paper because in modern paper making process the optical behavior of paper is strongly affected by using e.g. fillers, dye or coating colors. Futhermore, the opacity (optical density) of the paper is changed at different process stages like wet pressing and calendering. The greatest advantage of using beta transmission method to measure paper formation is that it can be very reliably calibrated to measure true basis weight variation of all kinds of paper and board, independently on sample basis weight or paper grade. This gives us the possibility to measure, compare and judge papers made of different raw materials, different color, or even to measure heavily calendered, coated or printed papers. Scientific research of paper physics has shown that the orientation of the top layer (paper surface) fibers of the sheet paly the key role in paper curling and cockling , causing the typical practical problems (paper jam) with modern fax and copy machines, electronic printing , etc. On the other hand, the fiber orientation at the surface and middle layer of the sheet controls the bending stiffness of paperboard . Therefore, a reliable measurement of paper surface fiber orientation gives us a magnificent tool to investigate and predict paper curling and coclking tendency, and provides the necessary information to finetune, the manufacturing process for optimum quality. many papers, especially heavily calendered and coated grades, do resist liquid and gas penetration very much, bing beyond the measurement range of the traditional instruments or resulting invonveniently long measuring time per sample . The increased surface hardness and use of filler minerals and mechanical pulp make a reliable, nonleaking sample contact to the measurement head a challenge of its own. Paper surface coating causes, as expected, a layer which has completely different permeability characteristics compared to the other layer of the sheet. The latest developments in sensor technologies have made it possible to reliably measure gas flow in well controlled conditions, allowing us to investigate the gas penetration of open structures, such as cigarette paper, tissue or sack paper, and in the low permeability range analyze even fully greaseproof papers, silicon papers, heavily coated papers and boards or even detect defects in barrier coatings ! Even nitrogen or helium may be used as the gas, giving us completely new possibilities to rank the products or to find correlation to critical process or converting parameters. All the modern paper machines include many on-line measuring instruments which are used to give the necessary information for automatic process control systems. hence, the reliability of this information obtained from different sensors is vital for good optimizing and process stability. If any of these on-line sensors do not operate perfectly ass planned (having even small measurement error or malfunction ), the process control will set the machine to operate away from the optimum , resulting loss of profit or eventual problems in quality or runnability. To assure optimum operation of the paper machines, a novel quality assurance policy for the on-line measurements has been developed, including control procedures utilizing traceable, accredited standards for the best reliability and performance.

• The korean journal of orthodontics
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• v.34 no.6 s.107
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• pp.506-513
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• 2004

Osteoclast action is necessary for alveolar bone remodeling in orthodontic tooth movement. The nervous system has also been reported to be associated with bone remodeling. This study was aimed to investigate the changes of osteoclasts in the periodontal ligament (PDL) space after surgical resection of the inferior alveolar nerve (IAN). Experimental rats were divided into young and adult groups. A surgical resection procedure of the IAN was carried out in the left side of the mandible and a sham operation in the right side of the mandible. The number of osteoclasts on the bundle bone surface and the resorption activity of the osteoclasts were histomorphometrically measured. The changes in distribution of substance P (SP) immunoreactive (IR) nerve fiber were evaluated in the PDL and pulp. SP-IR nerve fiber was depleted in both the PDL and pulp of the IAN resection side in both groups, which confirmed the resection of IAN to be successfully conducted. The number of osteoclasts in the IAN resection side was significantly reduced in both the young and adult groups (p<0.01 and p<0.05), whereas the resorption activity of osteoclasts did not show any significant difference between the IAN resection side and the sham operation side in both groups (p>0.05 and p<0.05). The adult group showed that the number of osteoclasts reduced significantly (p<0.01) and the resorption activity didn't change in comparison with the young group (p>0.05). These results suggest that surgical resection of the IAN and aging reduce the population of the recruited osteoclasts within the PDL, but don't affect on the osteoclastic resorption activity.

• Journal of Periodontal and Implant Science
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• v.32 no.1
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• pp.89-112
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• 2002

The earliest reports of the use of electrical energy to directly stimulate bone healing seem to be in 1853 from England, the techniques involved the introduction of direct current into the non-united fracture site percutaneously via metallic needles, with subsequent healing of the defect. One endpoint of the periodontal therapy is to generate structure lost by periodontal diseases. Several procedural advances may support regeneration of attachment, however, regeneration of alveolar bone does not occur consistently. Therefore, factors which stimulate bone repair are areas for research in periodontal reconstructive therapy. Effects of cytokines or growth factors on bone repair are examples of such areas. Another one is electrical current which occurs in bone naturally, so that such bone may be particularly susceptible to electrical therapy. The purposes of this study were to observe the effects of electrical stimulation on the normal periodontium, to determine whether the electricity is the useful means for periodontal regeneration or not. Forty rats weighted about 100 gram were used and divided into 4 groups, the first group, there was no electrical stimulation with the connection of electrodes only. In the second group, there was stimulated by the 10 mA during 10 minutes per a day, in the third group was stimulated by the 25 mA , and the fourth by the 50 mA. At 3, 5, 10 and 15 days post-appliance , two rats in each group were serially sacrificed. and the maxillae and the mandible processed to paraffin, and the specimens were prepared with Hematoxylin-Eosin stain for the light microscopic evaluation. The results of this study were as follows : 1. There was the distinct reversal line on the lingual alveolar crest, whereas a little changes in the labial alveolarcrest to the duration and amount of currents. 2. In 50 mA group, the cells were highly concentrated at the apex of anterior teeth, and was observed the necrotic tissue. In posterior root apex, the hypercementosis was appeared, and newly formed cementum layer has been increased continuously with the time. 3. The periodontal ligament fiber and Sharpey's fiber were arranged in order, and the bone trabeculae were increased as the experiment proceeded by, relatively the bone marrows were decreased. 4. In the pulp tissue, the blood vessels were increased with blood congestion in the experimetal specimens remarkably, and the dentinal tubules were obstructed . 5. The osteoblasts in alveolar bone proper had been showed highly activity, and also observed the formation of bone trabeculea. In the conclusion, it was suggested that the electrical stimulation has influence on the periodontium and the pulp tissue. However, there might be the injurious effects.

• Journal of Conservation Science
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• v.37 no.6
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• pp.712-722
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• 2021

This study presents a method for conserving shamanistic spirits in Chiseonggwang Buddha. Scientific investigation has revealed that these spirits have been subject to degeneration as a result of severe exfoliation and pollution. The materials and preservation treatment techniques used in create these shamanistic spirits were identified through visual inspection and using appropriate scientific equipment. The different types of background paper, background material, and color pigments used in create the shamanistic spirits were analyzed using a colorimeter, stereoscopic microscope, and SEM-EDS techniques. The analysis revealed that the pulp paper was used as the background and synthetic fiber polyester as the background material. In addition, the study of the pigment revealed that the color components were all synthetic, except for red lead [Pb₃O₄] and oyster shell white [CaCO₃]. Moreover, it was confirmed that the green pigment, identified as emerald green [Cu(C₂H₃O₂)₂.3Cu(AsO₂)₂], was a major component of shamanistic spirits in the late 19^th century. The shamanistic spirits in Chiseonggwang Buddha were conserved by identifying raw materials and pigments through this detailed analysis.

• Journal of the korean academy of Pediatric Dentistry
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• v.39 no.1
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• pp.58-65
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• 2012

The crown-root fracture is defined as a fracture of tooth that contains enamel, dentin and cementum with or without pulp exposure. Generally the fracture lines place obliquely from labial surface, between incisal edge of the crown and marginal gingiva, to palatal surface subgingivally. If the fracture line is located supragingivally, the removal of tooth fragment and supragingival restoration can be performed. In subgingival fracture line, the surgical exposure, orthodontic eruption or surgical eruption can be considered. If the fracture line is too deep to restorate, extraction or decoronation can be selected. In children and adolescents, the extraction should be the last option. Another option to select before extraction is the restoration using fiber-reinforced post and the reattachment of tooth fragment. The fiber-rainforced post enhances the retention and the durability of tooth fragment. The reattachment of crown fragment using resin adhesive system is considered minimal invasive treatment biologically. This case reports the treatment of crown-root fracture using the reattachment of crown fragment and the insertion of fiber-reinforced post.

• Journal of the Korean Society of Clothing and Textiles
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• v.32 no.9
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• pp.1366-1375
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• 2008

This studies were carried out in order to develope environmentally-friendly fiber materials and substitute resources of Paper mulberry. Various plant fibers such as New Zealand flax, Indian mallow, Kuzu vine and Yucca were used as raw materials of hand-made papers. We rotted these 4 kinds of plant fibers and removed non-cellulose. After rotting, the pulping rate(%) and the length of fibers in pulps were measured. The physical characteristics of papers made of various plants fiber were investigated and the probabilities of practical use were considered. The results were as follow: The non-cellulose contents of plant fibers were $30{\sim}40%$ and those contents must be lower down to 8% to be able to manufacture the hand made papers. The lignin in pulps were removed almost and the hemicellulose were partially removed to reach up to appropriate level of the pulp rates and fiber lengths. The more hemicellulose removed, the finer fiber thickness were and rapidly the lower Hanji tensile strength were. But the tear strength of these plants of hand-made papers do not decreased so much as tensile strength. So the property of 4 types of plant fibers might be of great advantages to make hand-made papers. Both tensile and tear strengths of Hanji of New Zealand flax, Indian mallow, Kuzu vine and Yucca were higher than Paper mulberry hand-made paper. When 30% of mulberry paper were mixed, the mixing effect showed maximum. Because of the functions of all plant fiber hand-made papers showed better than those of Paper mulberry hand-made paper, 4 types of plant fibers could be substitute Paper mulberry.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2011.10a
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• pp.39-41
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• 2011

The recycling rate of recovered paper in Korea is the highest in the world, 92%, but remanufacturing yield is low due to the extremely poor quality of the paper. The poor quality, in turn, influences to the reject amount in deinking process. To increase the yield of old newspaper recycling process, hydrophobic degree of inorganic pigments of deinking stock must be reduced. To determine the hydrophobicity, Pitch Potential Deposit Tester (PDT) was newly designed and applied with respect to the SB latex property of various quality used in Korea; its hydrophobic degree according to Tg, gel content, charge and particle size of latex and optimum designing condition of SB latex. And below are the conclusions: 1. The reason of excessive reject from old newspaper deinking process for total amount of printed ink is loss of inorganic pigments. When lipase, a biochemical catalyst, was applied with the purpose of preventing inorganic pigments loss about more than 70% of total reject weight and promoting hydration of pulp for deinking, deinking process yield of pre flotation secondary stage increased remarkably without any changes of deinking efficiency. 2. Lipase improved deinking stock by cutting ester linkage on surface of hydrophobic materials to promote its hydration. From this, it reached the conclusion that hydration degree of stock exercises significant effect on flotation deinking process yield. 3. Inorganic alkali promotes hydration of deinking stock. But there have been needs for more fundamental measures other than inorganic alkali of promoting hydration for yield improvement. For this, this study intended to find out reasons of chemical properties change on surface of hydrophobic material by change of pH. 4. Pitch Deposit Test (PDT) was performed for understanding principle of why surface of coating flake from OMG is hydrophobic and why it becomes hydrophilic when pH of stock is alkaline. As a result of this test, it is determined that swelling property by change of pH of latex film, which were used as coating adhesive is the reason for hydrophobic change. 5. Hydrophilicity of coating flake increased with hydrophilic pigments. And as more of SB Latex adhesive was used and higher of calcium hardness of stock became, its hydrophilicity decreased. SB Latex adhesive film is reformed by mechanical friction. For having hydrophilicity under neutral pH, strong bruising action such as kneading is required. 6. Because swelling of adhesive film decreases as Tg of SB latex gets lower and mean diameter gets smaller, it shows hydrophobicity under neutral pH. This lowers hydrophilicity of coating flake, which leads to easy elimination with flotation reject on DIP process. Therefore, for improving future flotation yield, it is necessary to develop to use eco-friendly clean SB latex by raising Tg and increasing mean diameter for recycling, and as a result, to reduce excessive loss of coating flake as a reject from deinking process.

• Korean Journal of Human Ecology
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• v.17 no.6
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• pp.1205-1213
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• 2008

Material is a factor for maximizing formative aspect among fashion design factors. Therefore, central axis of modern fashion is performing various trials for escaping from existing cloth and searching for artistic value. Especially, Korean paper is a formative material, which is manufactured through traditional manual work in Korea. The material is used in various fields on the basis of its aesthetic feature. Especially, fashion field performs handcraft activity on the basis of mulberry pulp, which is a prime material of Korean paper. Because the activity can be reinterpreted by world designers, who want to find motive of fashion material in the third world, it is necessary to perform experimental study for developing expressive form on the basis of diversity of Korean paper material. Therefore, the purpose of this study is to perform experimental study by focusing on the development of Korean paper material in order to express formative feature. The study purposes are as follows. The first purpose is to reinterprete the theory through actual work of fiber formation using Korean paper in the current flow where art and design field are fused and compromised. The second purpose is to suggest vision of material development on the basis of formative feature to fashion world focusing its eyesight to Asia and the third countries. The study results are as follows. First, Korean paper has been evaluated as proper material for the fusion of design and art because of its handicraft feature, long-term preservation, heat insulation, absorption, diversity and eastern feature. Second, the study performed various trials for artistic dress material by developing 12 Korean paper works and suggested the development of new material on the basis of formative feature of modem fashion industry.

• Applied Chemistry for Engineering
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• v.10 no.2
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• pp.299-303
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• 1999

In this paper, to investigate the deinkability of domestic and Australian old newsprint according to aging time, two types of newsprint printed with commercial offset ink in domestic(K; Korean newsprint, C; Canadian newsprint), Japanase(J) and Australian(A) old newsprint were aged naturally for 10, 30, 90, 180 days, and then yield, brightness, fiber length, and physical properties (tensile index, tear index, burst index) were evaluated according to aging time. As the aging time increased, the yield and brightness of respective samples decreased. The brightness and yield were decreased in the order of A, K, J and C. The brightness and strength of newsprint varied according to the ink formulation and kinds of pulp and wood. The decreasing order of strength is subsequently J, K, C and A.

• Journal of Korean Society of Forest Science
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• v.14 no.1
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• pp.33-38
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• 1972

This study was carried out to investigate on the variation of wood fiber dimensions of some oakwoods. Every 2 annual ring was selected for specimens from pith toward bark up to 28th annual ring on 3 species of Oak SINGALNAMOO(Quercus mongorica Fisch.), JOLCHAMNAMOO(Quercus serrata Thunb.) and KULCHAMNAMOO(Quercus variabilis Blume) which grew in Mt. Jiri. The investgated results are as follows: 1. Values of wood fiber lengths increase rapidly up to 16th annual ring, however, considerably stable at the rear part. Range of wood fiber length variations: Species Range of length(mean) CV SINGALNAMOO, $640{\sim}1,544{\mu}$($1,142.3{\mu}$), 8~16% JOLCHAMNAMOO, $592{\sim}1,600{\mu}$($1,179.6{\mu}$), 6~21% KULCHAMNAMOO, $679{\sim}1,592{\mu}$($1,298.9{\mu}$), 2~15% 2. The increment of wood fiber width and thickness by annual rings shows quite inactive contrary to the length. Range of wood fiber width: $7.6{\sim}10.0{\mu}$(mean $9.3{\mu}$) Range of wood fiber thickness: $2.0{\sim}3.2{\mu}$(mean $2.6{\mu}$) 3. There was no significance between species through their wood fiber lengths. 4. And these wood fibers believed to be valuable for pulp-wood through their fiber bonding ratio, Runkel ratio and flexibility coefficient.