• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.41 no.3
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• pp.60-64
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• 2009

Paper is easily damaged by physical and chemical deterioration under several factors. Damaged paper cultural heritage is usually restored by Lining. A traditional method of Lining is attaching the lining paper behind the original paper cultural heritage using starch and water. It supports the weakened quality of paper. In Japan, paper cultural heritage is restored with "Washi" which is made from mixture of Paper mulberry and Japanese cedar. In the west, the lining paper made from Paper mulberry, which has extraordinary excellent conservativeness, is usually used as a restoration material for paper. But Japanese Washi has dominated the demand for restoration materials as the most preferred restoration paper, and most kinds of paper made from Paper mullbery have been called as 'Japanese paper'. Result showed that the strength of the Korean lining papers was generally higher than that of the Japanese ones. As a result from measuring the rate of dimensional change after water-immersion and drying, sample B of the Korean lining papers and sample E of the Japanese lining papers showed the highest stability.

• Journal of the Korean Ceramic Society
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• v.36 no.2
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• pp.159-166
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• 1999

The physical properties and microstructural changes with heat-treatment of opacified silica aerogels doped by TiO2 were investigated. Monolithic SiO2-TiO2 aerogels were prepared by supercritical drying (25$0^{\circ}C$, 1250 psig) of wet gel obtained by adding titanium isopropoxide to prehydrolyzed TEOS-isopropanol solutions. The density and the porosity of SiO2-10 mol% TiO2 aerogels were 0.23 g/㎤ and 90%, respectively. During supercritical drying, the linear shrinkage of aerogels increased with increase in the titanium content an TiO2 was transformed to the anatase phase as well as particls agglomerates led to TiO2 clusters of 100~800 nm dispersed homogeneoulsy in the silica matrix. The IR transmittance of opacified silica aerogels was very low in the region of wavelengths below 8 ${\mu}{\textrm}{m}$ compared with pure silica aerogels and SiO2-TiO2 aerogels showed the high thermal stability of microstructures up to $600^{\circ}C$.

• Food Science and Preservation
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• v.12 no.1
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• pp.54-61
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• 2005

The absorption characteristics and their physical properties of hot air, vacuum and freeze dried soybean curd powder were investigated. Absorption conditions were at 5, 15, and 25 t with $0.11\~0.93$ water activities. Equilibrium moisture content and the monolayer moisture content determined by prediction models showed highest value in the freeze dried soybean curd powder due to porous structure. Absorption energy decreased with increasing water activity was not affected by drying method. In the comparisons of the isothermal absorption models, Oswin model generally was the best fit model for isothermal adsorption of soybean curd powder.

• Journal of the Korean Wood Science and Technology
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• v.22 no.1
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• pp.54-65
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• 1994

This research carried out to investigate the effects of inorganic materials in paper sludge on the thermal degradation and of paper sludge addition on physical and mechanical properties of paper sludge-wood particle mixed boards in comparison with unmodified particleboards. Also these unmodified particleboards and paper sludge-wood particle mixed boards were soaked in aqueous solutions of fire-retardant chemicals(diammonium phosphate and zinc chloride), and their fire retardancy were tested by oxygen index method and ISO ignition test to determine the feasibility of paper sludge, industrial waste, as a recyclable resource in fabrication of fire-resisting panels for building material. Since the redrying of fire-retardant treated particleboards and paper sludge-wood particle mixed boards were made by press drying method, this process was a simple and effective method. On the other hand, flexural bending strength and internal bonding strength were also analysed to evaluate mechanical properties through standard method.

• Journal of the Korean Applied Science and Technology
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• v.32 no.3
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• pp.405-411
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• 2015

Carbon composites for flexible fiber heating element were examined to improve the electrical conductivity in this study. Carbon composites using carbon black, denka black, super-c, super-p with/without CNF or dispersant such as BCS03 and Sikament-nn were prepared. Carbon composite slurry was coated on plane film and yarns(cotton, polyester) and the performances of prepared heating materials were investigated by checking electrical surface resistance, adhesion strength. The plane heating element using carbon black under natural drying condition($25^{\circ}C$) had better physical properties such as surface resistance(185.3 Ohm/sq) and adhesion strength(above 90%) than those of other carbon composite heating elements. From these results, polyester heating element coated by carbon black showed better electrical line resistance(33.2 kOhm/cm) than cotton heating element. Then, it was found that polyester heating element coated by carbon black with CNF(3 wt%) and BCS03(1 wt%) appeared best properties(0.604 kOhm/cm).

• Science of Emotion and Sensibility
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• v.17 no.4
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• pp.71-78
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• 2014

Composite draw textured yarns(DTY) and air jet textured yarns(ATY) with hollow PET filament have been used for making high emotional fabrics including light weight sports wear garments. This study investigated effect of hollow composite yarns and fabric structural parameters to the comfort properties related to the moisture and thermal transport phenomena for the composite fabrics made of DTY and ATY with hollow PET filament. Wicking property of hollow composite fabric was superior at the high pore size fabric and was not influenced by fabric cover factor. Wicking property of the fabric with ATY was better than that of the fabric with DTY. On the other hand, drying rate of fine pore sized fabric was shorter than that of large pore sized fabric and drying rate of high multi yarn fabric with low cover factor and small pore size was superior than that of hollow composite fabric. The pore size of the fabric was dominant factor in the air permeability and thermal conductivity of hollow composite fabric. High pore sized fabric showed high air permeability and thermal conductivity of hollow composite fabric was nonlinearly inversely proportional to pore size of the fabric.

• Polymer(Korea)
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• v.37 no.4
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• pp.526-532
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• 2013

The effect of CNT dispersion method on rheological and electrical properties of polystyrene/carbon nanotube (PS/CNT) nanocomposites via latex technology was compared. The nanocomposites were prepared through freeze-drying the dispersed suspension comprised of CNTs and PS particles. In this study, physical dispersion method, either sodium dodecylsulfate (SDS) addition or polyvinyl pyrrolidone (PVP) wrapping, was employed to prevent the deterioration of intrinsic properties of CNT caused by chemical modification. The physical method applied to latex technology was very effective in CNT dispersion. With SDS addition, the enhancement of rheological properties was low compared to PVP wrapping because the properties of matrix were deteriorated due to the incorporation of low molecular weight SDS. The electrical percolation threshold of PS/SDS-stabilized CNT and PS/PVP-wrapped CNT nanocomposites was 0.23 and 0.90 wt%, respectively. The enhancement of electrical conductivity was low in the case of PVP wrapping because the non-conducting PVPs wrapped around CNT restricted the electrical connection between CNTs.

• Journal of Korea Foundry Society
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• v.43 no.3
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• pp.107-136
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• 2023

Natural silica sand was commonly used for sand casting of cast steel products, and chromites sand was used to suppress seizure defects due to the lack of thermal properties of silica sand. However there are disadvantages such as deterioration by repeated use, system sand mixing problem, difficulty separating and removing, increased during mold according to high density and to being waste containing chrome. Recently, industrial waste reduction and atmospheric environment improvement have been highlighted as important tasks in the casting industry. In order to solve the problems that occur when using foundry Sand and to improve the environment of casting factories, various artificial sands that can be applied instead of natural silica sand have been developed and introduced. Artificial sands can be classified into artificial sand manufactured by the electric arc atomization or gas flame atomization, artificial sand manufactured by the spray drying & sintering process, artificial sand manufactured by the sintering & crushing process and exhibit different physical properties depending on the type of raw-minerals and manufacturing method. In this study, comparative evaluation tests were conducted on the physical properties of various foundry sands, mold strength, physical durability, thermal durability, and casting test pieces. When comprehensively considering the actual amount of molding sand used according to density, the mold strength according to the shape of sand, the physical and thermal durability of foundry sand, and the heat resistance characteristics of foundry sand, 'Molten artificial sand A1' or 'Molten artificial sand B' is judged to be the most suitable spherical artificial sand for casting of heavy steel castings.

• Food Science and Preservation
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• v.31 no.2
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• pp.218-226
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• 2024

The oriental melon poses challenges in terms of long-term storage and distribution. Addressing these issues requires an extension of the storage life through appropriate processing. In this study, pretreated hot-air dried oriental melon slices (steamed and freeze-thawed) were prepared, and their physicochemical and organoleptic properties were examined. The control group (CON) consisted of hot-air dried oriental melon slices without pretreatment, while the steamed group (STG) and freeze-thawed group (FTG) consisted of hot-air dried oriental melon slices pretreated using steaming and freeze-thawing methods, respectively. The moisture contents detected in the CON, STG, and FTG groups ranged from 15.96% to 27.30%, with variations of 7.53 to 8.40 °Brix for the soluble solid contents. The CON group showed the highest Hunter color value for lightness (L^*) and the lowest value for redness (a^*). The texture profile analysis revealed the highest hardness and chewiness in the order of STG > CON > FTG. Considerable differences were observed in springiness and adhesiveness in the FTG group compared to the other groups. The organoleptic evaluation showed that the CON group had the highest sensory scores for overall preference. These findings indicate that the properties of hot-air dried oriental melon slices were influenced by physical pretreatments and that manufacturing these slices without pretreatment is the most effective method in terms of processing simplicity and cost efficiency.

• Food Science of Animal Resources
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• v.34 no.1
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• pp.33-39
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• 2014

This study investigates the effects of the gelatin concentration (10-40%, w/v), freezing temperatures (from $-20^{\circ}C$ to $-50^{\circ}C$) and freezing methods on the structural and physical properties of gelatin matrices. To freeze gelatin, the pressure-shift freezing (PSF) is being applied at 0.1 (under atmospheric control), 50 and 100 MPa, respectively. The freezing point of gelatin solutions decrease with increasing gelatin concentrations, from $-0.2^{\circ}C$ (10% gelatin) to $-6.7^{\circ}C$ (40% gelatin), while the extent of supercooling did not show any specific trends. The rheological properties of the gelatin indicate that both the storage (G') and loss (G") moduli were steady in the strain amplitude range of 0.1-10%. To characterize gelatin matrices formed by the various freezing methods, the ice crystal sizes which were being determined by the scanning electron microscopy (SEM) are affected by the gelatin concentrations. The ice crystal sizes are affected by gelatin concentrations and freezing temperature, while the size distributions of ice crystals depend on the freezing methods. Smaller ice crystals are being formed with PSF rather than under the atmospheric control where the freezing temperature is above $-40^{\circ}C$. Thus, the results of this study indicate that the PSF processing at a very low freezing temperature ($-50^{\circ}C$) offers a potential advantage over commercial atmospheric freezing points for the formation of small ice crystals.