• Applied Chemistry for Engineering
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• v.23 no.4
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• pp.421-427
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• 2012

To improve the lubricity of ultra low sulfur diesel, vegetable oil-based alkanol amide derivatives were prepared and their lubricity properties were studied. To synthesize the alkanol amides, we conducted the amidation reaction of diethaolamine High Frequency Reciprocating Rig (HFRR) and the fatty acid methyl esters, obtained by the continuous transesterification of methanol and several vegetable oil, such as soybean oil, palm oil and coconut oil. The synthesized amides were soluble in ultra low sulfur diesel in the concentration range of ca. 1 wt%; the lubricating properties of ultra low sulfur diesel containing 120 ppm of amides were measured using an HFRR method. It was found that the wear scar diameter in the pure ultra low sulfur diesel decreased significantly from 581 ${\mu}m$ to 305~323 ${\mu}m$ upon the addition of the amides, indicating that lubricating properties of the diesel were improved. On the other hand, the types of vegetable oils did not affect the wear scar diameters, implying that lubricating properties of the diesel did not depend strongly on the structures of alkyl groups of alkanol amide derivatives. When we measured the lubricating properties of the one type of diesels containing various amounts of alkanol amide, we observed that the wear scar diameter decreased drastically with increasing the amide concentration, meaning that the lubricity improved with the amide concentration.

• Korean Journal of Food Science and Technology
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• v.26 no.2
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• pp.117-122
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• 1994

The characteristics of amylose-lipid complex(AL-complex) and cyclodextirn-lipid complex(CL-complex) were investigated by using Differential Scanning Calorimetry(DSC). The enzymatic hydrolysis of amylose which was liberated from AL-complex by the addtion of ${\beta}-cyclodextrin({\beta}-CD)$was also studied. The melting temperatures of AL-complex in corn, wheat, and rice starch were above $100^{\circ}C$ and there were no differences among them. In the presence of lysolecithin, the melting enthalpy and temperature of AL-complex were increased and lysolecithin was very effective in the formation of AL-complex. When ${\beta}-CD$ was added to AL-complex, the endothermic peak of AL-complex at $100^{\circ}C$ decreased and that of CL-complex at $70^{\circ}C$ appeared. These results indicated that the amylose was released from AL-complex by substituting ${\beta}-CD$ for amylose, then by forming CL-complex. As the added amount of ${\beta}-CD$ increased, the peak of AL-complex decreased whereas that of CL-complex increased. Enzymatic hydrolysis rate of AL-complex increased in the presence of ${\beta}-CD$, suggesting that amylose was dissociated from AL-complex and hydrolyzed by amylase.

• Journal of Adhesion and Interface
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• v.9 no.1
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• pp.28-34
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• 2008

This study was used particleboard with urea-formaldehyde resin and cross linking vinyl resin. Manufactured particleboard had high cross linking vinyl resin content that internal bonding strength was low value but flexural strength was increased. For emission test of particleboard using VOC Analyzer, it was confirmed that more cross linking vinyl resin had reduced 4 volatile organic compounds (Toluene, Ethylbenzen, Xylene, Styrene) but also TVOC (Total VOC), 5 VOCs (Benzene, Toluene, Ethylbenzen, Xylene, Styrene) and formaldehyde emissions from manufactured particleboard were also lower emission factor than particleboard with only urea formaldehyde resin.

• Journal of Adhesion and Interface
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• v.19 no.2
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• pp.74-82
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• 2018

Many methods for cross-linking acrylic PSAs have been discussed previously. For high cross-linking density, epoxy functionalized monomer and methyl aziridines as cross-linking agents were used in this study. Additionally, photopolymerization using different UV doses was investigated to synthesize a binder because of its rapid productivity. FT-IR analysis, curing behaviours and adhesion performance were examined for the relationship between UV doses and temperature as curing conditions. According to the results, the gel fraction was over 50% even at $120^{\circ}C$ after UV curing at a dose of $800mJ/cm^2$. On the other hand, while gel fractions of all samples reached approximately 80% only at $180^{\circ}C$ in thermal curing for 1 hour, gel fractions of the samples after thermal curing for 3 hours increased rapidly above $120^{\circ}C$ regardless of UV doses and reached approximately 100% at $180^{\circ}C$. This means that the second cross-linking reaction, esterification, is mainly dependent on the curing temperature.

• Journal of the Korean Wood Science and Technology
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• v.49 no.2
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• pp.107-121
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• 2021

The purpose of this study is to optimize the bonding method of the plywood suitable for cross-laminated timber (CLT) with plywood as a core by analyzing the flexural performance and failure mode according to the lamina species, the method of bonding plywood in the longitudinal direction, and whether or not adhesive is applied to the joint. In the case of the Douglas fir lamina layer, the modulus of elasticity decreased by about 11.5% due to longitudinal bonding, and the modulus of rupture increased or decreased according to the adhesive application and bonding method. The optimal conditions were derived as the butt joint without adhesive, half lap joint with adhesive, and butt joint. In the case of the larch lamina layer, the modulus of rupture and the modulus of elasticity decreased by about 15% and 40%, respectively. When using the half lab joint and tongue & groove joint, it is believed that it reduces the load transmitted to the middle layer by primarily preventing the failure on flexure at the joint of the plywood layer. From the results of this study, the larch lamina layer used in the manufacturing process of Ply-lam CLT did not show any difference based on the bonding method. Butt joint and half lap joint bonding method are determined to be suitable when using Douglas fir lamina layer.

• Tribology and Lubricants
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• v.13 no.1
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• pp.82-87
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• 1997

The modern orthopaedics frequently uses the total hip replacement in the artificial hip joint. The wear in this joint requires a re-replacement of hip joints because it is under the severe load and friction conditions. To solve these problems the previous studies have been mainly focussed on the development of new materials. The research of new materials, however, needs much time and effort since it should be experimented for its bio-compatibility, friction, and wear characteristics. To reduce the work, in this study, the finite element analysis is applied to find new combinations of bio-materials in the total hip replacement which has the excellent contact characteristics. A non-linear FEM program MARC with 5-node axisymmetric element was used for analyzing the contact stresses between the hip joints. The computed results show that in case of acetabulum UHMWP has good characteristics, in femoral head, $Al_2O_3$, and in stem, Ti6Al4V.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.42 no.3
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• pp.14-21
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• 2010

Three different species of cattails (Typha orientalis, Typha angustata, Typha latifolia) cultivated in South Korea were examined as raw materials for the production of pulp and paper. Soda pulping with anthraquinone was used for the stems and the leaves of cattail, separately. Addition of anthraquinone in soda pulping improved the yield greatly. Chemical components between three cattail species and within each species (leaves and stem) gave little differences. Average fiber length of the bleached cattail fibers was a little shorter than that of the HwBKP of Eucalyptus. Average fiber width of the cattail fibers was a half of that of the HwBKP. Compared to the HwBKP, cattail pulp gave higher breaking length, higher opacity, and better smoothness at equivalent freeness.

• Elastomers and Composites
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• v.50 no.1
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• pp.62-67
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• 2015

The surface modification of microfibriled cellulose (MFC) was carried out through the hydrolysis-condensation reaction using (3-aminopropyl)triethoxysilane (APS) and 3-glycidyloxypropyltriethoxysilane (GPS) and then the modified cellulose was compounded with bio-degradable poly(lactic acid) (PLA). Also, pristine MFC was compounded with PLA as a control groups. The confirmation of surface modification for the pristine MFC was characterized by FT-IR and SEM/EDX. The thermal and mechanical properties of the PLA/MFC composites depended on the content of MFC and the type of silane coupling agents. From the thermal, morphological and mechanical behaviors of the PLA/MFC composites, it was found that GPS-MFC was more successful to improve the interface adhesion between PLA matrix and the surface of MFC than that of APS-MFC.

• Journal of Powder Materials
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• v.13 no.6 s.59
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• pp.432-438
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• 2006

Aluminum nitride (AlN) nanopowders with low degree of agglomeration and uniform particle size were synthesized by carbothermal reduction of alumina and subsequent direct nitridization. Boehmite powder was homogeneously admixed with carbon black nanopowders by ball milling. The powder mixture was treated under ammonia atmosphere to synthesize AlN powder at lour temperature. The effect of process variables such as boehmite/carbon black powder ratio, reaction temperature and reaction time on the synthesis of AlN nanopowder was investigated.

• International Journal of Industrial Entomology and Biomaterials
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• v.28 no.1
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• pp.19-24
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• 2014

Silk has always been one of the most favored textile materials. Fully degummed silk fiber (i.e., silk fibers without sericin) shows better luster than raw silk fiber (with sericin); it is also softer. On the other hand, raw silk fiber feels cooler because of the presence of sericin, making it useful as a textile for the summer season. Recently, partially degummed silk has attracted researchers' attention because it provides better luster, feel, and dyeing properties. However, the partial degumming of silk is very difficult because it results in inhomogeneously degummed fiber. In the present study, silk yarns were degummed with surfactant aqueous solutions and the effects of each surfactant on the degumming ratio, crystallinity, and homogeneity of the degummed silk yarn were examined. The degumming ratio and crystallinity index of silk yarn varied depending on the type of surfactant. On the whole, anionic surfactants resulted in higher degumming ratios and better homogeneity than nonionic surfactants.