• Journal of the Korean Chemical Society
• /
• v.22 no.1
• /
• pp.37-44
• /
• 1978

The effect of lithium chloride on the borane reduction of organic compounds was studied for three ketones, seven acid derivatives, three epoxides and cyclohexene in tetrahydrofuran at $0^{\circ}$. When compared with borane itself, borane-lithium chloride system enhanced the rates of reductions markedly of 2-heptanone, acetophenone, benzoyl chloride, phthalic anhydride, and three epoxides, whereas the reductions of benzophenone, four esters and cyclohexene showed little or no effect. $BH_3$-LiCl (1 : 0.1) reduced styrene oxide in 2 hr at $0^{\circ}$ to give 94.2 % yield of alcohols, 1-to 2-phenylethanol ratio being 60.8 to 39.2. And in the reduction of cyclohexene oxide, $BH_3$-LiCl (1 : 0.1) gave a quantitative yield of cyclohexanol in 2 hr at $0{\circ}$, however $BH_3$-LiCl (1 : 1) gave 58 % cyclohexanol and 42 % 2-chlorocyclohexanol. In the reduction of cyclohexene oxide, lithium nitrate showed no rate enhancement even when the salt was added in large excess. A formation of lithium chloroborohydride in the$BH_3$-LiCl system is suggested.

• Korean Journal of Materials Research
• /
• v.9 no.10
• /
• pp.1037-1040
• /
• 1999

Magnetic characteristics of some anisotropic mischmetal- FeB- (Co,Ti,Al) permanent magnets have been investigated. The magnets were fabricated by using hot-pressed and die-upsetting. Hot-pressed $\textrm{(MM)}_{12.5}\textrm{Fe}_{71.9}\textrm{Co}_{5.0}\textrm{Al}_{2.0}\textrm{B}_{8.6}$ permanent magnet showed $\textrm{H}_{c}$=4.27 kOe, $\textrm{B}_{r}$=4.75 kG, $\textrm{(BH)}_{max}$=3.82 MGOe, and die- upset magnet showed $\textrm{H}_{c}$=3.10 kOe, $\textrm{B}_{r}$=5.58 kG, $\textrm{(BH)}_{max}$=5.34 MGOe, respectively. Hot-pressed $\textrm{(MM)}_{12.5}\textrm{Fe}_{77.9}\textrm{Ti}_{1.0}\textrm{B}_{8.6}$ permanent magnet showed $\textrm{H}_{c}$=3.75 kOe, $\textrm{B}_{r}$=4.64 kG, $\textrm{(BH)}_{max}$=2.78 MGOe, and die- upset magnet showed $\textrm{H}_{c}$=3.29 kOe, $\textrm{B}_{r}$=5.01 kG, $\textrm{(BH)}_{max}$=3.54 MGOe, respectively. X-ray diffraction and transmission electron microscopy revealed that the higher energy products in the die-upset magnets results from alignment of the c-axis along the die-upsetting direction. The magnetic anisotropy in hot-pressed MM-FeB- Al magnet is increased by the substitution of Co for Fe.

• Asian-Australasian Journal of Animal Sciences
• /
• v.11 no.3
• /
• pp.255-259
• /
• 1998

Sixteen Friesian Cows were allocated equally into 4 groups in a $4{\times}4$ Latin square design to evaluate the effects of utilizing bean by-products on the feed intake and milk production. Cows were fed on 4.5% of their body weight fresh alfalfa; the remainder of their requirements were covered by one of 4 experimental concentrate treatments: 1) commercial concentrate (CC), 2) 70% CC + 30% bean hulls (BH), 3) 70% CC + 30% Polished bean (PB) and 4) 70% CC+ 15% BH + 15% PB. Results showed that the inclusion of bean hulls at 30% improved (p<0.05) milk yield, 4% fat corrected milk yield, feed conversion ratio and fat percent of the milk over the other treatments. Feeding cows on a commercial concentrate plus 30% BH or 30% PB or 15% from each of BH and PB decreased the cost of feed per kg milk by 13.6, 2.5 and 1.3 %, respectively, lower than those fed on the commercial concentrate.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.23 no.6
• /
• pp.780-788
• /
• 1986

1.3\ulcorner GaInAsP BH(Buried Heterostructure) lasers were fabricated on the p-InP substrate. Two step chemical etching processes and melt-back etching technique during 2nd epitaxy were used for BH active layer. BH laser had the threshold current, Ith, of 72mA(23\ulcorner), peak wavelength of 1.2937\ulcorner, nd of 10-20%, and To of 85K. They operated in single mode under pulse condition up to 1.4 Ith. CW(DC) operation was successfully performed at room temperature.

• Journal of Chest Surgery
• /
• v.44 no.2
• /
• pp.99-107
• /
• 2011

Background: Calcification is the most frequent cause of clinical failure of bioprosthetic tissues fabricated from GA-fixed porcine valves or bovine pericardium. A multi-factorial approach using different mechanisms was recently developed to reduce the calcification of bioprosthetic tissues. The purpose of the present study was to evaluate the synchronized synergism of using L-arginine and $NaBH_4$, compared with ethanol and L-lysine, in glutaraldehyde treated porcine pericardium from the standpoint of calcification and tissue elasticity. Materials and Methods: Porcine pericardium was fixed at 0.625% GA (7 days at room temperature after 2 days at $4^{\circ}C$). An interim step of ethanol (80%; 1 day at room temperature) or L-lysine (0.1 M; 2 days at $37^{\circ}C$) or L-arginine (0.1 M; 2 days at $37^{\circ}C$) was followed by completion of the GA fixation. A final step of NaBH4 (0.1 M; 2 days at room temperature) was followed. Their tensile strength, thickness, and thermal stability were measured. Treated pericardia were implanted subcutaneously into three-week-old Sprague-Dawley rats for 8 weeks. Calcium content was assessed by atomic absorption spectroscopy and histology. Results: L-arginine and $NaBH_4$ pretreatment ($1.81{\pm}0.39$ kgf/5 mm p=0.001, $0.30{\pm}0.08$ mm p<0.001) significantly increased tensile strength and thickness compared with the control ($0.53{\pm}0.34$ kgf/5 mm, $0.10{\pm}0.02$ mm). In a thermal stability test, L-arginine and $NaBH_4$ pretreatment ($84.25{\pm}1.12^{\circ}C$, p=0.023) caused a significant difference from the control ($86.25{\pm}0.00^{\circ}C$). L-lysine and $NaBH_4$ pretreatment ($183.8{\pm}42.6$ ug/mg, p=0.804), and L-arginine and $NaBH_4$ pretreatment ($163.3{\pm}27.5$ ug/mg, p=0.621) did not significantly inhibit calcification compared to the control ($175.5{\pm}45.3$ ug/mg), but ethanol and $NaBH_4$ pretreatment did ($38.5{\pm}37.3$ ug/mg, p=0.003). Conclusion: The combined pretreatment using L-arginine and $NaBH_4$ after GA fixation seemed to increase the tensile strength and thickness of porcine pericardium, fixed with GA. Additionally, it seemed to keep thermal stability. However it could not decrease the calcification of porcine pericardium fixed with GA. $NaBH_4$ pretreatment seemed to decrease the calcification of porcine pericardium fixed with GA, but only with ethanol.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2001.09a
• /
• pp.172-175
• /
• 2001

이 연구에서는 5개의 시추공에 대한 양수시험을 실시하여 대수층의 수리학적 이방성과 지하수의 주 유동방향을 규명하고자 하였다. 코아검층 및 초음파주사검층을 통해 각각의 공에 대한 균열방향을 결정하고 이를 토대로 통합해본 결과 크게 세 방향의 균열군이 집중성을 보였다. 가장 빈도가 높은 균열의 방향은 N0$^{\circ}$~40$^{\circ}$E/30$^{\circ}$~50$^{\circ}$SE 그리고 N30$^{\circ}$~ 80 $^{\circ}$W/20$^{\circ}$~50$^{\circ}$ NE이 방향이 함께 나타났으며 두 번째 균열의 방향은 N0$^{\circ}$ ~50$^{\circ}$E/60$^{\circ}$ ~80$^{\circ}$NW로 나타났다. 세 번째 방향은 N30$^{\circ}$~50 $^{\circ}$W/70$^{\circ}$~80$^{\circ}$SW방향의 균열로 구성된다. 이처럼 지표하에서는 크게 세 방향의 균열이 다른 방향을 보이는 균열에 비해 상대적으로 큰 빈도를 가지며 발달하고 있음을 알 수 있다. 대수층이 이방성이고 균질하다는 가정하에 양수시험을 실시하여 각각의 공에 대한 최대 투수량계수 ( $T_{{\varepsilon}{\varepsilon}}$)와 최소 투수량계수 ( $T_{ηη}$)값을 산출하고 주 텐서방향 ($\theta$)을 결정하였다. 그 결과 BH-1, BH-4, BH=5공을 제외한 BH-2, BH-3호공에서의 이방성 투수량계수텐서값은 이 논문의 가정인 대수층이 이방성이고 균질하다는 가정에 일치하지 않았다. 따라서 원형좌표계에 도시하였을 때 다른 공에 비해서 비균질성이 심한 결과로 인해 이방성타원체 에서 많이 벗어남을 보였다. 이로인해 3개의 공 BH-1, BH-4, BH-5호공을 사용하여 대수층의 이방성을 분석하여 보았다. BH-1호공에서의 $T_{{\varepsilon}{\varepsilon}}$는 171.90 $m^2$/day, $T_{ηη}$는 71.0l $m^2$/day이고 주 텐서방향은 Nl5.39$^{\circ}$ E로 나타났다. BH-4호공의 $T_{{\varepsilon}{\varepsilon}}$는 268.20 $m^2$/day, $T_{ηη}$는 28.75 $m^2$/day이고 주 텐서방향은 N7.55$^{\circ}$E이며 BH-5호공에서의 $T_{{\varepsilon}{\varepsilon}}$는 168.40 $m^2$/day, $T_{ηη}$는 66.80 $m^2$/day이고 주 텐서방향은 N76.59$^{\circ}$E로 나타났다. 이처럼 연구지역에서의 각각의 공에 대한 투수량계수텐서는 서로 다르게 나타났으며 이에 따른 주 텐서방향도 서로 다름을 알 수 있다.

• Transactions of the Korean hydrogen and new energy society
• /
• v.25 no.5
• /
• pp.475-481
• /
• 2014

Ammonia borane ($NH_3BH_3$), as a source material for energy generation and hydrogen storage, has attracted growing interest due to its high hydrogen content. We have investigated the synthesis of ammonia borane from sodium borohydride ($NaBH_4$) and ammonium chloride ($NH_4Cl$) utilizing a low-temperature process. From our results, we obtained a maximum synthetic yield of 98.2% of ammonia borane complex. The diammoniate diborane (DADB) was detected in about 5~10mol% with in the solid ammonia borane by solid-state $^{11}B$-NMR analysis. The synthesized solid ammonia borane products were studied to characterize hydrogen release upon thermal dehydrogenation.

• The Bulletin of The Korean Astronomical Society
• /
• v.37 no.1
• /
• pp.46.2-46.2
• /
• 2012

The black hole mass-stellar velocity dispersion ($M_{BH}-{\sigma}_*$) relation observed in the present-day universe has motivated numerous studies on the black hole-galaxy co-evolution. It is crucial to define the$M_{BH}-{\sigma}_*$ local active galaxies since cosmic evolution of the correlations is calibrated based on the local relation. However, stellar velocity dispersion is difficult to measure in active galaxies due to much higher AGN continuum than stellar pseudo-continuum, resulting in a small sample with reliable velocity dispersion measurements for studying the AGN $M_{BH}-{\sigma}_*$ relation. To increase the sample size and improve the measurements, we obtained high S/N near-IR spectra for 3 local AGNs, i.e., NGC 3227, Akn 120, 3C 390.3, for which reverberation black hole masses are measured, using the TripleSpec at the Palomar 5-m Telescope. By investigating aperture effect and correcting for rotation component, we determine the luminosity-weighted ${\sigma}_*$, based on the spatially resolved kinematics and compare them with optical measurements from literature. Combining our new measurements with literature data, we present an improved $M_{BH}-{\sigma}_*$ relation for the enlarged sample of reverberation-mapped AGNs.

• Bulletin of the Korean Chemical Society
• /
• v.30 no.4
• /
• pp.863-868
• /
• 2009

New spiro[fluorene-7,9′-benzofluorene]-based blue host material, 5-phenyl-spiro[fluorene-7,9′-benzofluorene] (BH-1P), was successfully prepared by reacting 5-bromo-spiro[fluorene-7,9′-benzofluorene] (1) with phenyl boronic acid through the Suzuki reaction. 5-(N,N-Diphenyl)amino-spiro[fluorene-7,9′-benzofluorene] (BH-1DPA) and diphenyl-[4-(2-[1,1;4,1]terphenyl-4-yl-vinyl)-phenyl]amine (BD-1) were used as dopant materials. 2,5-Bis-(2',2"- bipyridin-6-yl)-1,1-diphenyl-3,4-diphenylsilacyclopentadiene (ET4) and Alq3 were used as electron transfer materials. Their UV absorption, photoluminescence and thermal properties were examined. The blue OLEDs with the configuration of ITO/DNTPD/$\alpha$-NPD/BH-1P:5% dopant/$Alq_3$ or ET4/LiF-Al prepared from the BH-1P host and BH-1DPA and BD-1 dopants showed a blue EL spectrum at 452 nm at 10 V and a luminance of 923.9 cd/$m^2$ with an efficiency of 1.27 lm/W at a current density of 72.57 mA/$cm^2$.

• Transactions of the Korean hydrogen and new energy society
• /
• v.33 no.4
• /
• pp.343-352
• /
• 2022

Co/Al₂O₃ nanopowder was used as a catalyst to investigate the effect of catalyst support, reduction temperature, sodium borohydride (NaBH₄) concentration, sodium hydroxide (NaOH) concentration, and reaction temperature on the characteristics of NaBH₄ hydrolysis. The Co/Al₂O₃ nanopowder showed a high catalytic activity among various catalysts. Catalyst reduction at 250℃ exhibited a relatively good activity. The activity decreased with an increase in the NaBH₄ concentration. Conversely, the activity increased and then decreased with an increase in the NaOH concentration. Additionally, the activity increased with an increase in the reaction temperature. The value of apparent activation energy was 40.81 kJ/mol, which was lower than the other Co-based catalysts. Thus, Co/Al₂O₃ nanopowder catalyst can be widely used for NaBH₄ hydrolysis owing to its superior catalytic activity.