• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.1009-1011
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• 2012

In this paper, a wavelength tunable light source based on mutually injected locking with two F-P LDs, has been constructed and then analyzed for wavelength shift and RIN (Relative Intensity noise) according to temperature. We have measured maximum about 2 nm for the wavelength shift and minimum -110dB/hz for the RIN. Also, the RIN and beating noise in eye patterns are increased by changing temperature high.

• Journal of the Korean Wood Science and Technology
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• v.42 no.3
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• pp.251-257
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• 2014

For new use development of miscanthus sinensis var. purpurascens, which investigated properties of ceramics made from different carbonization temperature ($600{\sim}1,200^{\circ}C$) and percentage of resin impregnation(30~60%) using a mincanthus board. As the carbonization temperature increased, the density, thickness shrinkage, linear shrinkage, weight loss were increased. As the percentage of resin impregnation increased, the density, linear shrinkage and weight loss were increased. On the other hand, thickness shrinkage decreased.

• Journal of the Korean Wood Science and Technology
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• v.49 no.4
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• pp.360-370
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• 2021

For the purpose of finding new uses for Miscanthus sinensis var. purpurascens, this study first constructed boards with the particles of the plant and impregnated them with phenolic resin at resin impregnation rates of 30 ± 2%, 40 ± 2%, 50 ± 2%, and 60 ± 2%. The impregnated boards were then carbonized at the carbonization temperature of 800℃, after which their density and mechanical properties were examined according to the different resin impregnation rates. The results showed that density, flexural strength performance, Brinell hardness, and compressive strength increased as the resin impregnation rate increased, thus affecting the physical and mechanical properties of the ceramics made of M. sinensis var. purpurascens particles.

• Journal of the Korean Wood Science and Technology
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• v.30 no.2
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• pp.158-164
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• 2002

The properties of new porous carbon materials "Woodceramics" are affected by the characteristics of raw boards. To investigate of density profile and resin contents in impregnated boards, control board and 3 types of steam-injected boards were made by steam injection time, The wood species used for manufacturing boards was Sugi(Cryptomeria japonica). The results are as follows: 1) The density gradient of board after 10 minutes steam injection was the smallest and non-steamed board was largest. 2) The resin content and dimensional rise decreased with increase of board density, and were the largest in board after 10minutes steam injection but there was little difference between boards after 5 and 10 minutes steam injection.

• Journal of the Korean Society of Propulsion Engineers
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• v.26 no.5
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• pp.1-10
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• 2022

For Cu-Cr alloy developed for rocket engines, estimated fatigue lives were calculated using various fatigue life prediction methods and compared with fatigue life acquired from low-cycle fatigue tests. The utilized methods for fatigue life prediction are as follows: Coffin-Manson relation, plastic/total strain energy density relations, Smith-Watson-Topper relation, Tomkins relation, and Jahed-Varvani relation. As results of estimation of fatigue lives, it satisfied within scatter band two compared to the test fatigue lives in all methods. The quantitative calculation of the deviation of predicted fatigue lives gives that the total strain energy density relation presents the best result.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2003.05a
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• pp.382-383
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• 2003

해만가리비(Argopecten irradians)는 미국의 대서양 연안과 걸프만이 원산지로 중국에서는 1982년 미국에서 이식한 이래 많은 양식생산이 이루어지고 있으며, 우리나라에서는 1996년 국립수산과학원 남해수산연구소에서 새로운 양식품종으로 개발하고자 최초로 이식하여 실내에서 인공종묘생산으로 치패를 생산한 바 있다. 국내에서는 연구로는 동절기 성장(Oh and Jung, 1999), 밀도별 성장(Oh et al. 2000), 양식 생물학적연구(Oh, 2000), 수심별 성장(Oh et al., 2002) 생식주기(Oh et al., 2002), 선발효과(Oh et al., 2002)등에 관한 연구를 수행한 바 있으며, 외국에서는 산란 및 생식상태(Loosanoff and Davis, 1963; Taylor and Capuzzo, 1983; Hampson and Capuzzo. (중략)

• Journal of the Korean Wood Science and Technology
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• v.41 no.4
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• pp.293-301
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• 2013

This study discusses the feasibility of coffee bean residue as a raw material of medium-density fiberboard (MDF). In this relation, the effect of coffee bean residue known as an absorbent material on the physical and mechanical properties of MDF manufactured at its different addition level. Coffee bean residue which is a by-product of coffee mill and large amount of waste left over after processing for instant coffee was added at the level of 3, 6, and 9% on dry basis and urea formaldehyde resin was used as the adhesive. The MDF made with mixture of wood fiber and coffee bean residue was tested for physical and mechanical properties as well as formaldehyde emission. The bending strength and internal bonding strength of the MDF made with mixture of wood fiber-coffee bean residue were higher than that of the KS standard in randomized mat structure type, but not in layered mat structure type. Also, the physical properties of MDF made with mixture of wood fiber-coffee bean residue showed a considerable improvement in thickness swelling over the commercial MDF. More importantly, the formaldehyde emission rate of MDF made with mixture of wood fiber-coffee bean residue met the KS standard and was close to that of commercial MDF. These results showed the feasibility of coffee bean residue as a raw material for the production of environmentally-friendly MDF. Additional works on adhesive-coffee bean compatibility, improvement of moisture absorption effect and reduction the formaldehyde emission rate by carbonization of coffee bean residue may be required.

• Korean Journal of Plant Resources
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• v.35 no.5
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• pp.686-695
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• 2022

The grain yield and flour quality of winter wheat (Triticum aestivum L. 'Jokyung') were investigated in the paddy fields in which the double-cropping of wheat linked to rice (Oryza sativa L.) and its alternative crops [black soybean (Glycine max (L.) Merr.), sesame (Sesamum indicum L.), and perilla (Perilla frutescens (L.) Britton)] was applied. In the soils in which black soybean, sesame, and perilla as pre-crops were cultivated, the soil pH was higher and the electrical conductivity was lower than in the rice pre-cropped soil. In addition, the available phosphate (Av. P₂O₅), and contents of Ca²⁺ and Mg²⁺ were higher than in the rice pre-cropped soil. Winter wheat growth characteristics such as culm length, spike length, number of spikes and grains were generally favorable in the black soybean pre-cropped soil. However, the grain yield of winter wheat increased in the black soybean, sesame, and perilla pre-cropped soils by 100 kg/10a or more than in the rice pre-cropped soil. Furthermore, protein content and SDS-sedimentation value of the flour were higher, while amylose content was slightly lower, in the black soybean, sesame, and perilla pre-cropped soils than in rice pre-cropped soil. These results suggest that cultivation of rice alternative crops such as sesame, black soybean, and perilla as pre-crops in paddy soil could improve the physical and chemical properties of the soil and contribute to producing high-quality wheat flour more advantageous for the baking process.

• Journal of Korean Tunnelling and Underground Space Association
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• v.16 no.2
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• pp.225-236
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• 2014

Shear wave velocity was used to estimate the geotechnical characteristics (void ratio and shear strength) of ground near an underground rainfall storage facility. An oedometer cell was utilized to measure the shear wave velocity and the displacement of specimens. Shear strengths were obtained by direct shear tests. The relationships along the shear wave velocity, void ratio, and shear strength were verified and used to infer the shear strength profile with the depth. In addition, changes in shear strength due to the construction of the underground rainfall storage system were estimated using the suggested method. The results show that the in-situ shear strength deduced from the shear wave velocity-void ratio-shear strength relationship is in good agreement with that obtained from an in-situ investigation (SPT).

• Journal of the Korean Wood Science and Technology
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• v.42 no.3
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• pp.223-230
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• 2014

This study examined emission characteristics of far-infrared ray, formaldehyde, volatile organic compounds and deodorization rate of particleboard prepared at different target board densities and resin content levels, using the xylem part of Broussonetia Kazinoki Sieb. The deodorization rate increased, as the target density of board and resin content increased. Emission rates of the far-infrared ray and total volatile organic compounds (TVOCs) were 0.892~0.899, and $0.074mg/m^2{\cdot}h$ for particleboard prepared with the resin content of 13% and target density of $0.6g/cm^3$ while the deodorization rate was 80~90% for the same particleboard. The formaldehyde emission factor ranged from $0.004mg/m^2{\cdot}h$ to $0.006mg/m^2{\cdot}h$ for all particleboard fabricated at different resin content and target densities. These results indicate that particleboard prepared from the xylem part of Broussonetia Kazinoki Sieb have a potential as a building construction material.