• Journal of Microbiology and Biotechnology
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• 제17권2호
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• pp.313-319
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• 2007

The nutritional medium requirement for biosurfactant production by Bacillus licheniformis K51 was optimized. The important medium components, identified by the initial screening method of Plackett-Burman, were $H_3PO_4,\;CaCl_2,H_3BO_3$, and Na-EDTA. Box-Behnken response surface methodology was applied to further optimize biosurfactant production. The optimal concentrations for higher production of biosurfactants were (g/l): glucose, $1.1;NaNO_3,\;4.4;MgSO_4{\cdot}7H_2O,\;0.8;KCl,\;0.4;CaCl_2,\;0.27;H_3PO_4,\;1.0ml/l;\;and\;trace elements\;(mg/l):H_3BO_3,\;0.25;CuSO_4,\;0.6;MnSO_4,\;2.2;Na_{2}MoO_4,\;0.5;ZnSO_4,\;6.0;FeSO_4,\;8.0;CoCL_2,\;1.0;$ and Na-EDTA, 30.0. Using this statistical optimization method, the relative biosurfactant yield as critical micelle dilution (CMD) was increased from $10{\times}\;to\;105{\times}$, which is ten times higher than the non-optimized rich medium.

• Bulletin of the Korean Chemical Society
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• 제22권12호
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• pp.1337-1340
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• 2001

The bulk photopolymerization of methyl methacrylate (MMA) with para-substituted phenylsilanes such as F-C6H4SiH3 (1), H3C-C6H4SiH3 (2), and H3CO-C6H4SiH3 (3) was performed to produce poly(MMA)s containing the respective silyl moiety as an end group. For all the hydrosilanes, the polymerization yields and the polymer molecular weights decreased, whereas the TGA residue yields and the relative intensities of Si-H IR stretching bands increased as the relative silane concentration over MMA increased. The polymerization yields and polymer molecular weights of MMA with 1-3 increased in the order of 3 < 1 < 2. These hydrosilanes influence significantly upon the photopolymerization of MMA as both chain-initiation and chain-transfer agents.

• 한국결정학회지
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• 제10권1호
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• pp.71-75
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• 1999

융액인상법에 의하여 Nd3+ 이온이 15 at% 주입된 LaSc3(BO3)4 단결정을 성장하였다. 최적의 결정성장 조건하에서 성장된 결정은 결정형이 잘 발달되고 보라색 투명하였다. 편광 현미경에 의한 결정결함 분석결과 성장된 결정 중심부에서 0.1 mm 크기의 기포가 검출되었고, B2O3가 증발하여 결정에 증착된 shoulder 부위에서는 균열이 발생되었으나 body에서는 결함이 검출되지 않았다. X선 회절에 의하여 cell parameter를 측정한 결과 a=7.73 , b=9.85 , c=12.05 , β=105.48o 및 공간군 C2/c의 monoclinic 구조로 분석되었다. 양질의 단결정을 성장하기 위한 결정성장 요소는 회전속도 10 rmp, 인상속도 1.5 mm/h이었다. 성장된 결정은 808 nm에서 강하고 넓은 흡수대와 1050∼1080 nm에 걸친 형광 방출대가 관찰되었다. 성장된 결정을 이용하여 직경 3 mm, 두께 1mm 크기의 micro-chip laser 소자의 제조기술을 확립하였다.

• 시멘트 심포지엄
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• 25호
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• pp.62-65
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• 1997

• Bulletin of the Korean Chemical Society
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• 제33권10호
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• pp.3279-3284
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• 2012

Poly(benzimidazole-co-benzoxazole)s (PBI-co-PBO) are synthesized by polycondensation reaction with 3,3'-diaminobenzidine, terephthalic acid and 3,3'-dihydroxybenzidine or 4,6-diaminoresorcinol in polyphosphoric acid (PPA). All polymer membranes are prepared by the direct casting method (in-situ fabrication). The introduction of benzoxazole units (BO units) into a polymer backbone lowers the basic property and $H_3PO_4$ doping level of the copolymer membranes, resulting in the improvement of mechanical strength. The proton conductivity of $H_3PO_4$ doped PBI-co-PBO membranes decrease as a result of adding amounts of BO units. The maximum tensile strength reaches 4.1 MPa with a 10% molar ratio of BO units in the copolymer. As a result, the $H_3PO_4$ doped PBI-co-PBO membranes could be utilized as alternative proton exchange membranes in high temperature polymer electrolyte fuel cells.

• 한국결정학회지
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• 제11권1호
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• pp.16-21
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• 2000

(Yb/sub x/Y/sub 1-x/)Ca₄O(BO₃)₃ single crystals where x=0.3,8,15,20% were grown by Czochralski Method. The crystals grown under the optimum conditions were transparent and colorless with good crystal form. Using polarizing microscope, crystal defects such as parasite crystals and bubbles were detected depending on the composition of melts and pulling rates. The optimum growth parameters for high quality of single crystals were 15∼20 rpm of rotation rate and 2mm/h of pulling rate at the flow rate of 2 l/min of Nitrogen gas. The relationship between crystal axes and optical axes was investigated by optical crystallographic method, polarization technique and single crystal X-ray method. From the spectroscopic measurements, it was confirmed that there were strong absorption bands at 900 and 976.4 nm and strong emission band at 976.4 nm in Yb/sup 3+/ ion doped YCa₄O(BO₃)₃ crystal. For the application of second harmonic generation of 1.064 ㎛ laser, non-linear optical devices with θ=32.32° and Ψ=0°, λ/10 of flatness and the size of 6x8x5.73 mm were fabricated from the grown YCa₄O(BO₃)₃ crystal.

• Asian-Australasian Journal of Animal Sciences
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• 제20권12호
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• pp.1791-1797
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• 2007

A study was conducted with 70 Hanwoo (Korean cattle) for genotyping bovine leukocyte antigen (BoLA)-DRB3.2 gene by using the polymerase chain reaction (PCR) and sequence based typing (SBT). Two-step PCR was carried out for amplifying a 284 bp fragment of the target gene and the PCR products were digested with three restriction enzymes namely RsaI, BstYI and HaeIII. Seventeen alleles were detected with frequencies ranging from 1.43 to 18.57% and one (x'aa) of these alleles was identified as a new allele that has not been reported before. The frequency of the new x'aa allele identified in this breed was 12.86%. In addition, the seven most frequently observed alleles (DRB3.2 *10, *15, *16, *26, *27, *54 and x'aa) accounted for 74.28% of the alleles in this population. The phylogenetic tree showed that the BoLA-DRB3.2 allele sequences of Hanwoo were shared with other Bos taurus breeds and no specific clade for Hanwoo was identified. It indicates high heterogeneity of the BoLA-DRB3 gene in this population and may give some ideas for breeding animals having better disease resistance.

• 생명과학회지
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• 제16권4호
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• pp.561-565
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• 2006

우리나라 과수 중 개화기가 빠른 복숭아는 저온에 의하여 화분발아 장해로 결실율이 저하되고 있다. 본 연구는 저온에서 화분 발아율을 증진시킬 수 있는 방법을 강구하기 위한 기초연구로서 화분 발아조건과 배지내에 sucrose, $CaCl_2$ 및 $H_3BO_3$ 첨가농도를 구명하고자 일련의 실험을 실시하였다. 복숭아 화분은 배지에 치상한 후 30분부터 발아가 시작되어 3시간 30분까지 지속되었으나, 그 이후는 더 이상 발아되지 않았다. 따라서 복숭아의 화분발아 판정을 위한 적정 시간은 치상 후 4시간이 좋았다. 복숭아 화분의 적정발아 온도는 $20^{\circ}C$였고, 이보다 저온이거나 고온에서는 화분발아율이 감소하였다. Sucrose는 화분발아를 촉진하였고 최적농도는 10%였다. 무기염류 중 $H_3BO_3$ 첨가는 '장택백봉'과 '수봉' 품종에서 화분 발아율을 무처리에 비해 $20{\sim}30%$ 증진시켰으며, 그 효과는 저온인 $10^{\circ}C$에서 현저하였다. 최적처리 농도는 $100\;mg\;{\cdot}\;L^{-1}$ 처리였다. 반면 $CaCl_2$ 첨가하면 화분발아율이 감소하였다. $10^{\circ}C$의 저온에서 화분발아율은 품종간에 뚜렷한 차이가 있었으며, '장택백봉', '백봉', '월미', '백도', '대구보', '유명', '수봉', '백미조생'의 순으로 화분발아율이 낮았다.

• 한국재료학회지
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• 제31권10호
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• pp.552-561
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• 2021

For the purpose of manufacturing a high efficiency TiO₂ photocatalyst, B-doped TiO₂ photocatalysts are synthesized using a plasma electrolytic oxidation method in 0.5 M H₂SO₄ electrolyte with different concentrations of H₃BO₃ as additive. For the B doped TiO₂ layer fabricated from sulfuric electrolyte having a higher concentration of H₃BO₃ additive, the main XRD peaks of (101) and (200) anatase phase shift gradually toward the lower angle direction, indicating volume expansion of the TiO₂ anatase lattice by incorporation of boron, when compared with TiO₂ layers formed in sulfuric acid with lower concentration of additive. Moreover, XPS results indicate that the center of the binding energy peak of B1s increases from 191.45 eV to 191.98 eV, which suggests that most of boron atoms are doped interstitially in the TiO₂ layer rather than substitutionally. The B doped TiO₂ catalyst fabricated in sulfuric electrolyte with 1.0 M H₃BO₃ exhibits enhanced photocurrent response, and high efficiency and rate constant for dye degradation, which is ascribed to the synergistic effect of the new impurity energy band induced by introducing boron to the interstitial site and the improvement of charge transfer reaction.

• 한국세라믹학회지
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• 제43권2호
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• pp.92-97
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• 2006

Dolomite type $BaSn(BO_3)_2$ ceramics with rhombohedral crystal structure has been synthesized via solid state reaction route. Dielectric properties were measured for the samples sintered at $1050\~1200^{\circ}C$ for 2 h in air. Dielectric constant, loss tangent, and temperature coefficient were increased with sintering temperature due to the evolution of $BaSnO_3$, secondary, phase. Optimum dielectric properties were obtained at the $BaSn(BO_3)_2$ ceramics sintered at $1100^{\circ}C.\;CuO/Bi_2O_3$ was added to $BaSn(BO_3)_2$ ceramics to lower the sintering temperature for LTCC application, then Co and Fe-based coloring agents were added for colorizing the LTCC tape. Typical dielectric properties of $BaSn(BO_3)_2$ ceramics with $5 wt\%\;CuO/Bi_2O_3\;and\;3wt\%$ Co-coloring agent that sintered at $900^{\circ}C$ were $\varepsilon_r=9.89,\;tan{\delta}=0.92\times10^{-3},\;and\;TCC=112ppm/^{\circ}C$. Thus obtained LTCC tape was co-fired with Ag paste for compatibility test and revealed no sign of Ag reaction with the ceramics.