• Journal of Power System Engineering
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• v.21 no.1
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• pp.50-56
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• 2017

To increase the enthalpy exchange efficiency of ERV elements, the moisture exchange character must be improved. The moisture exchange efficiency depends on material characteristics. The material used for ERV is Hwang-to paper based on Han-ji which is Korean traditional paper. The paper has excellent performance in moisture exchange and heat transfer compared with polymer and other papers. To have an anti bacteria performance and to improve moisture exchange performance of Han-ji, Hwang-to is added to the Han-ji. The enthalpy exchange efficiency of the Hwang-to paper shows 5% greater than that of the conventional paper. In case of Escherichia Coli, the reduction rate of bacteria is 96.6% and in case of Pseudomonas, the reduction rate of bacteria is 97.5%. The ERV element made of Hwang-to paper has a great possibility as an ERV element.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.36 no.5 s.108
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• pp.44-52
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• 2004

It is well known that Korean traditional Hanji have lots of predominant physical and optical properties such as high density, high air permeability, long lasting quality and lightness. The paper-making raw materials of traditional Korean Hanji are the bast fibre cooked from the Korean paper mulberry as a fibrous materials and sticky aqueous material from the root of Hibiscus anihot L. as additives for good dispersion of stock. Additionally, the mechanical properties of Hanji varies according to the cooking methods of bast tissues of Korean paper mulberry, the treatment methods of fibrous raw materials such as bleaching and refining, the wet formation types of sheet-making such as 'Oebal-chiji' and 'Ssangbal-choji', and the finishing treatment like stamping. This study was carried out to investigate and evaluate the quality properties of Korean traditional hand-made Hanji, and compared with commercial machine-made paper and modified prepared sheets. The physical quality comparisons of different kinds of Hanji were focused on the methods of hand-sheet making, the types of raw materials, the treatment of stamping, and the properties of ink reception and spreading.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.42 no.3
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• pp.7-13
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• 2010

KOptimization and control of wet-end process provide a key solution to improve paper quality and production efficiency at the same time. Wet-end of paper machine is to determine three important influencing factors of papermaking i.e., retention, drainage and formation. Good formation of paper could be made at the cost of deteriorated retention or drainage. In the same manner increase of retention aid could cause the bad formation of paper. It is very important to find a proper retention chemical which may satisfy one of three factors without the sacrifice of other two. Laboratory scale analyzing or screening chemical additives of wet-end was reported in this study based on RDA sheet molding. Different from the conventional test method, simultaneous consideration of three important wet-end properties could be made by RDA and consequently more reliable prediction of actual paper machine wet-end could be expected.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.40 no.2
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• pp.29-36
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• 2008

In order to give pulp surfaces anti-bacterial functionality and photo-catalytic deodorant ability, functional pulps was made using a surface modification method with Ag nano-colloidal solution and $TiO_2$ filler. Hygiene paper was made with the specially modified pulp, and anti-bacterial and deodorant tests were carried out. The Ag nano-colloidal solution was coated on the surface of the pulp using the high pressurized gas phase squirt through the spray nozzle mounted on the hybridization system. The surface modified functional pulp was hybridized with the optimum ratio of $TiO_2$(fine particle) to pulp(core particle) under the condition of $6,000{\sim}10,000$ rpm for $3{\sim}7$ minutes in the system. The anti-bacterial functionality of the hygiene paper was confirmed by the halo test in which the formation of the clear zone around the hygiene paper sample was observed. The inhibition growth test using MIC bioscreen C showed the inhibition growth effect of the bacteria as the reaction time was increased. The photo-catalytic effect measurement of the $TiO_2$ for 4 hours of the reaction showed $50{\sim}60%$ of decomposition rate, reaching over 60% for 5 hours of the reaction.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.35 no.2
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• pp.26-32
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• 2003

For the purpose of manufacturing water-resistant corrugated board boxes for agricultural products in the cold chain system, the effects of fiber types, wet strength agents and a moisture-proof chemical on the properties of the base papers were investigated first. PAE(polyamide amine epichlorohydrin) showed better performance than MF(melamine formalde-hyde) over broad stock pH ranges, which was prefered as wet strength agent for the paper grade. When short fibers(AOCC, KOCC) were mixed with long fiber(UKP) in certain ratios, some physical properties of the paper made with mixed fibers were similar to those of the paper made with UKP only. Paper containing AOCC showed the biggest increase in water resistance when PAE was added to the stock. Synergistic effects in moisture-proof and some mechanical properties of paper were appeared when PAR was added internally, together with the coating of a moisture proof chemical on the sheets.

• Journal of Sericultural and Entomological Science
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• v.41 no.3
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• pp.201-204
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• 1999

The silk/paper mulberry paper was prepared by recycling of the hard twisted silk waste and its mechanical properties was investigated. The silk waste was pretreated with sodium hydroxide(0.5%) and sodium carbonate(4%) to make it easy for beating and fibrillation. The silk/paper mulberry hand sheet paper has better mechanical properties of tearing strength and air permeability compared with the traditional and modified traditional paper. Treating with alkaline solution, the hard twisted silk waste could be used for an novel composite material.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 1999.11a
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• pp.17-22
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• 1999

In this paper a new discharge type ozonizer comprising the superpose operation of silent and surface discharge is presented. The ozonizer consists of two concentric glass tubes with three type of discharge electrodes : the external electrode(EE), the internal electrode(IE) and the central electrode(CE). By varying the structure of IE and materials of CE, we analyzed the characteristics of ozone related different parameters including $O_{3con}$, $O_{3g}$, and $O_{3Y}$. Using Cu made CE it was found the O3con is higher with Cu tape than that with Cu coil wound IE. At Q = 1[l/ min] the values of O3con were found as 3000[ppm] with Cu tape wound IE and 1898[ppm] with Cu coil wound IE. Then using SUS wire made CE with Cu tape wound IE at Q = 1[ι/ min] the maximum value of O3con was found as 5632[ppm]. It was observed that both $O_{3con}$ and $O_{3y}$ are higher with SUS made CE than that with Cu made CE. The maximum values of $O_{3Y}$ were found as 79[g/kWh] with Cu made CE and 170[g/kWh] with SUS wire made CE.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.5
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• pp.532-538
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• 2004

MEMS technology applying to the sensors and micro-electro devices is complete system. These microsystems are made by variable processes. Especially, the mentallization process has very important functions to transfer the power operating the sensor and signal induced from sensor part. But in the structures of MEMS the local stress concentration and deformation are often yielded by an irregular geometrical shape and different constraint. Therefore, this paper studies the effect of supporting type and thickness ratio about thin film of the substrate on the residual stress variation when the thermal loads is applied to the multi-layer thin film fabricated by metallization process. Specimens were made from several materials such as Al, Au and Cu. Then, uniform thermal load was applied, repeatedly. The residual stress was measured by FE Analysis and nano-indentation method using AFM. Generally, the specimen made of Al induced the larger residual stress than that of made of other materials. Specimen made of Cu and Au having the low thermal expansion coefficient induces the minimum residual stress. Similarly, the lowest indentation length was measured by nano-indentation method in the Si/Au/Cu specimen. Particularly, clusters are created in the specimen made of Cu by thermal load and the indentation length became increasingly large by cluster formation.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.33 no.4
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• pp.15-20
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• 2001

The function of the moisture-proof paper is to prevent moisture from adsorbing into the packed goods. Water-vapor transmission rate of the moisture-proof paper should be less than 100g/$m^2$.24hr and the optimum rate would be less than 50g/$m^2$.24hr. In general the moisture-proof paper has been made by laminating polyethylene or polypropylene on top of the base paper. However this kind of moisture-proof paper has a problem in recycling so that it brings about environmental pollution. In general the moisture-proof paper has been made by laminating polyethylene or polypropylene on top of the base paper. However this kind of moisture-proof paper has a problem in recycling so that it brings about environmental pollution. The purpose of this paper was to make moisture-proof paper using the mixture of SB latex and wax emulsion which was recyclable and environmentally friendly. Water vapor transmission rate showed less than 50g/$m^2$.24hr in mixture ratio of 85:15, 87:13, 90:10. Especially the mixture ratio of 87:13 showed the most favorable water-vapor transmission rate. However, the moisture-proof layer was destroyed slightly by folding in packing. It has been observed that there was no close relationship between water-vapor transmission rate of the moisture-proof paper and grammage of the base paper, but the density of base paper had influenced on water vapor transmission rate. It was also observed that the moisture-proof paper could be recycled. The moisture-proof paper was similar to base paper in degree of the pulping, and there was no significant difference in dispersion between moisture-proof paper and base paper. Most of wax particles which caused the spots during drying process could be removed by flotation process. Tensile strength and tear strength of both moisture-proof paper and base paper after pulping were measured to examine the fiber bonding, and no significant difference in physical properties was observed.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.36 no.1
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• pp.75-80
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• 2004

This research was peformed to manufacture a shroud using hanji and to investigate the characteristics of the hanji shroud manufactured. A hanji shroud were manufactured by considering the designs of the traditional costumes of shroud. The vast fibers were used for the manufacture of hanji. The shroud manufactured could keep the natural feeling of hanji. The shroud showed the feasibility in sewing compared to textiles. However, fine needlework was required due to the poor appearance of small holes made by changing of sewing line. Since the hanji shroud has excellent ability in preservation for a long-term period and economical advantages compared to the shroud currently made by hemp and cotton cloth, the demand of the hanji shroud may be increased in the near future.