• 한국분말재료학회지
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• 제9권5호
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• pp.352-358
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• 2002

The effects of boron or manganese added as $B_4C$, Mn, $TiB_2$, B on TiC-30vo1.%$Ni_3Al$ cermet sintered at 1380 and $1400^{\circ}C$ for 1 hour, were examined in relation with shrinkage, relative density, microstructure, lattice parameter, hardness and fracture toughness ($K_{IC}$). The results are summarized as follows: 1) The highest shrink-age showed about 30.5% in the specimen added B$_4$C and the maximum relative density was about 99% in the specimen added $TiB_2$; 2) The grains of TiC were grown during sintering and made the surrounding structure by adding boron and manganese. The largest grain size showed about $2.8\mutextrm{m}$ in the specimen with boron sintered at $1400^{\circ}C$;3) The lattice parameter of TiC was about $4.325\AA$ and $Ni_3Al$ about $3.592\AA$ by adding other elements; 4) The highest hardness was about $1100kgf/\textrm{mm}^2$ in the specimen with B4C; 5) The fracture toughness ($K_{IC}$) showed about $15MNm^{-3/2}$ in the specimen added $TiB_2$.

• 한국세라믹학회지
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• 제46권1호
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• pp.53-57
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• 2009

The h-BN powder was synthesized by amorphous $B_2O_3$ and activated carbon at $1550^{\circ}C$ in nitrogen atmosphere, whose properties were examined according to $MgB_6$ addition. Amount of $MgB_6$ addition was varied in the range of $0{\sim}$10\;wt% of the initial mixture. It was observed that $MgB_6$ addition led to an increase in the amount and the grain size of h-BN and decrease in the amount of $B_4C$ forming. When $MgB_6$ added 5 wt%, the amount and crystallinity of h-BN increased as the holding time at the synthesis temperature was prolonged. It was also confirmed that the regularity of three-dimensional ordering of h-BN increases.

• 한국주조공학회지
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• 제7권4호
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• pp.358-365
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• 1987

To investigate the grain refining mechanism of Al by the addition of Ti-B, the unidirectional solidifications of 99.9%Al and 99.7%Al were performed under the condition of varing the pouring temperature. The solidification modes of Al were studied by the cooling curve analyses, metallographic and microprobe examinations. The results were as follows: 1) Grains were most refined with an addition of 0.15wt.%Ti-0.021wt.%B but the grain size with 0.2wt.%Ti-0.028wt.%B was increased. 2) The grain size of 99.7wt.%Al was even more refined than that of 99.9wt.%Al with the same amount of Ti-B. 3) As the pouring temperature increased, the grain size of pure Al and an alloy with 0.lwt.%Ti-0.014wt.%B was increased. However, an alloy with 0.2wt.%Ti-0.028wt.%B did not show any effects of temperature. 4) TiC(Al-Ti) and (Al-Ti-C) were identified as nucleants for Al.

• 한국초전도ㆍ저온공학회논문지
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• 제9권2호
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• pp.15-18
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• 2007

The sub micron sized spherical $MgB_2$ powders were synthesized by spray reaction method. $MgB_2$ tapes with Al addition were fabricated by Powder in Tube (PIT) method. The superconducting property and microstructure of Al doped $MgB_2$ tapes were characterized by X-ray diffraction, optical microscopy and transport measurement under magnetic field. The $J_c$ value of $MgB_2$ tapes was increased with 10 vol. % Al addition. The $J_c$ value of 5,500 A/$cm^2$ and 11,000 A/$cm^2$ at 4.2 K and 5 T were obtained for the $MgB_2$ tape and 10 vol. % of Al added $MgB_2$ tape without heat treatment, respectively. The $J_c$ value of 8,000 A/$cm^2$ and 33,000 A/$cm^2$ at 4.2 K and 5 T were obtained for the $MgB_2$ tape and 10 vol. % of Al added $MgB_2$ tape with heat treatment, respectively. The $J_c$-B curves show enhancement in $J_c$ (B), which suggests that the microstructure and transport properties of $MgB_2$ tapes have been improved with Al addition.

• Tribology and Lubricants
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• 제12권3호
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• pp.48-54
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• 1996

Examined in this paper, is the effect of B$_{4}$C addition on the frictional characteristics of Cu-Sn based sintered friction materials. For the specimens 1wt%, 2wt% and 4wt% of B$_{4}$C were added into the reference material. A pin-on-disk type friction tester was used to,measure the friction torque with respect to the surface temperature and sliding distance. Wear mechanism of each specimen is analyzed in the view point of the oxide film formation. The specimen containing 4wt% of B$_{4}$C showed stable friction and low wear since the oxide film was sustained up to higher surface temperature ranges.

• Journal of Magnetics
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• 제18권3호
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• pp.240-244
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• 2013

The influences of Gallium doping on the magnetic microstructures and corrosion behaviors of Nd-Fe-B-Ti-C alloys are investigated. The cooling rate for obtaining fully amorphous structure is raised, and the glassforming ability is improved by the Ga addition. The High Resolution Transmission Electron Microscopy image shows that the ${\alpha}$-Fe and $Fe_3B$ soft magnetic phases become granular surrounded by the $Nd_2Fe_{14}B$ hard magnetic phase. The rms and $({\Delta}{\varphi})_{rms}$ value of Nd-Fe-B-Ti-C nanocomposite alloy thick ribbons in the typical topographic and magnetic force images detected by Magnetic Force Microscopy(MFM) decreases with 0.5 at% Ga addition. The corrosion resistances of $Nd_9Fe_{73}B_{12.6}C_{1.4}Ti_{4-x}Ga_x$ (x = 0, 0.5, 1) alloys are enhanced by the Ga addition. It can be attributed to the formation of more amorphous phases in the Ga doped samples.

• 한국세라믹학회지
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• 제35권3호
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• pp.287-293
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• 1998

The effects of B2O3 addition on the sintering behavior and th microwave dielectric properties of $(Mg_{0.93}Ca_{0.07})TiO_3$ ceramics were investigated. By addition of $B_2O_3$, increases the density of the ceramics increases and grain growth enhances, It was densified to over 94% of $(Mg_{0.93}Ca_{0.07})TiO_3$ theoretical density by the addition of 0.15-1.0wt% B2O3 and stable microwave dielectric properties observed by the addition of 0.2-0.4wt% $B_2O_3.\;(Mg_{0.93}Ca_{0.07})TiO_3$ ceramics sintered at $1200^{\circ}C$ exhibits maximum dielectric constants of 24-25 quality factor($Q{\times}f$) of more than 70000 and temperature coefficient of resonant frequency of $0\;ppm/^{\circ}C$ by adding of 0.15-0.4wt% $B_2O_3$.

• 한국초전도저온공학회:학술대회논문집
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• 한국초전도저온공학회 2002년도 학술대회 논문집
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• pp.3-4
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• 2002

The stainless steel sheathed MgB$_2$ tapes with Cu addition were fabricated by PIT method without heat treatment. The $J_{c}$ value of 5,600 A/ $cm^{2}$and 16,000 A/$cm^{2}$ at 4.2 K and 5 T were obtained for the $MgB_{2}$ tape and 10 vol % of Cu added $MgB_{2}$ tape respectively. The $J_{c}$-B curve shows enhancement in J$_{c}$ under magnetic field, which suggests enhancement in flux pinning property with Cu addition.n.

• 한국식품저장유통학회지
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• 제6권4호
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• pp.463-468
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• 1999

충청도 지방에서 유래하는 인삼박을 첨가한 약주의 특성 및 개발 가능성을 검토한 결과, pH는 A, B, C 모두 2단 담금 직후 감소하였다가 서서히 증가하는 경향이었고, 산도는 발효중 증가하는 경향을 나타내었으며 누룩과 조효소제 및 분말효모를 사용한 A에서 발효 4일째 pH 7.05, 산도 0.84로 가장 높았다. 알콜함량은 발효 4일째에 배양효모를 이용한 B(21.0%) 와 C(20.4%)가 분말효모를 이용한 A(19.0%)보다 높았다. 또한 알콜발효중 인삼박 첨가에 따른 발효저해는 나타나지 않으며 아미노태질소 함량은 조효소제를 첨가한 A와 C에서 높았다. 유리당은 누룩과 조효소제를 함께 이용한 A에서 glucose 599.16, maltose 129.llmg%, 총당 함량 736.06mg%로 가장 높았다. 유리아미노산 함량도 A가 580.02mg%로, 누룩을 이용한 B의 527.48mg%, 조효소제를 이용한 C의 538.74mg% 보다 높았다. 관능검사 결과 누룩을 첨가한 A와 B의 경우 40대 연령층에서, 조효소제를 첨가한 C는 20대 연령층에서 색과 향에 대한 기호도가 높았다. 그러나 맛에 대한 평가와 전반적인 기호도에서는 누룩을 이용한 B구간이 가장 높은 점수를 나타내었다. 따라서 인삼박을 이용한 약주의 상품화를 위하여 체계적인 담금 방법에 관한 연구가 요구되었다.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1996년도 제23회 춘계학술대회
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• pp.99-107
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• 1996

Examined in this paper is the effect of B$_{4}$C addition on the frictional characteristics of Cu-Sn based sintered friction material. For the specimens 1%, 2% and 4% of B$_{4}$C were added into the reference material. A pin-on-disk type friction tester was used to measure the friction and wear with respect to the surface temperature and sliding distance. Wear mechanism of each specimen is analyzed in the view point of the oxide film formation. The specimen containing 4% of B$_{4}$C showed stable friction and low wear since the oxide film was sustained up to higher surface temperature ranges.