• Analytical Science and Technology
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• v.5 no.4
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• pp.389-399
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• 1992

Liquid Chromatographic behavior of Pd(II) in Isonitrosoethylacetoacetate lmine, $Pd(IEAA-NR)_2$ (R=H, $CH_3$, $C_2H_5$, $n-C_3H_7$, $C_6H_5-CH_2$, $n-C_4H_9$) chelates were investigated by reversed-phase HPLC on Micropak MCH-5 column using methanol/water as mobile phase. The optimum conditions for the separation of $Pd(IEAA-NR)_2$ chelates were examined with respect to the effect of the flow rate, sample solvent, mobile phase strength and column temperature. It wass found that metal chelates were properly eluted in an acceptable range of capacity factor value($0{\leq}log\;k^{\prime}{\leq}1$). The dependence of the logarithm of capacity factor(k') on the volume fraction of water in the binary mobile phase was examined. Also, the dependence of k' on the liquid-liquid extration distribution ratio($D_c$) in methanol-water/n-alkane extration system was investigated. Both kinds of dependence are linear, which susggests that the retention of the electroneutral metal chelate is largely due to the solvophobic effect. Standard adsorption enthalpy changes (${\Delta}H^{\circ}$) and standard adsorption entropy changes (${\Delta}S^{\circ}$) of Pd(II) Isonitrosoethylacetoacetate imine chelates on Micropak MCH-5 column were calculated by measuring capacity factor with changing temperature of the column.

• Applied Chemistry for Engineering
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• v.32 no.3
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• pp.357-360
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• 2021

Emulsions were prepared using a mixture of bio-oil obtained from the pyrolysis of sawdust in an N₂ environment and Quercus mongolica in a CH₄ environment for both non-catalytic and catalytic cases. Both prepared emulsions were examined by measuring the physical stability and Fourier transform infrared spectroscopy. The emulsion with HLB 5.8 (Span 80 and Atlox 4916) for the ratio of bio-oil (B-oil and C-oil): surfactant: diesel = 10% : 3% : 87% showed stability for 15 days. Combining oils produced in N₂ and CH₄ environments could be a potential solution for generating high-quality emulsions with a high heating value.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.216.1-216.1
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• 2010

본 연구는 최근 하이드레이트와 유사한 형태인 semi-clathrate 형성을 통해 열역학적 촉진제로서 주목받고 있는 TBAF(Tetra-n-butyl ammonium fluoride)의 가스 하이드레이트 형성에 작용하는 영향을 알아보았다. TBAF를 10, 33.8, 45 wt%의 농도로 $CH_4+H_2O$, $CO_2+H_2O$, $N_2+H_2O$계에 첨가하여 가스 하이드레이트 3상 평형점(하이드레이트(H) - 물(Lw) - 기상(V)) 측정을 하였다. TBAF가 첨가된 경우 순수한 $CH_4$, $CO_2$, $N_2$ 가스 하이드레이트보다 평형조건이 더 높은 온도와 더 낮은 압력 영역에서 나타났으며 기체의 종류와 무관하게 TBAF의 농도가 33.8 wt%일 때 10, 45 wt%보다 뛰어난 촉진효과를 갖고 있음을 확인할 수 있었다. 이를 통해 양론비인 TBAF의 농도 33.8 wt% 이상에서는 반응을 하지 않고 남아있는 TBAF가 하이드레이트 생성반응에 방해요소로 작용하는 것을 알 수 있었다. 본 실험에서 얻어진 결과 TBAF를 촉진제로서 사용하는 가스 하이드레이트 공정이라면 33.8 wt% 농도의 사용이 가장 효과적일 것으로 사료된다.

• Bulletin of the Korean Chemical Society
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• v.23 no.2
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• pp.221-224
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• 2002

Nucleophilic addition reactions of benzylamines (BA; $XC_6H_4CH_2NH_2$) to ethyl-${\alpha}$-cyanocinnamates (ECC;$YC_6H_4CH$=C(CN)COOEt) have been investigated in acetonitrile at $30.0^{\circ}C$. The rate is first order with respect to BA and ECC. The rate is slower than that expected from the additive effect of ${\sigma}^-$ or $R^-$ for the activating groups (CN and COOEt). Natural. bond orbital ${\pi}^{\ast}_{c=c}$ calculations show that the contribution of COOEt group may not be fully effective despite the coplanar molecular structure. The selectivity parameters including the cross-interaction constant (${\rho}_{xy}$ = -0.22) indicate that the addition occurs in a single step. The kinetic isotope effects ($k_H/k_D$=2.5-2.8) involving deuterated BA ($XC_6H_4CH_2ND_2$) nucleophiles and activation parameters (${\Delta}H^{\neq}=4{\sim}6\;kcal\;mol^{-1};{\Delta}S^{\neq}=-45{\sim}-52\;e.u.$) suggest a cyclic transition state in which N-$C_{\alpha}$ and H-$C_{\beta}$ bonds are formed concurrently.

• Korean Journal of Soil Science and Fertilizer
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• v.38 no.3
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• pp.150-156
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• 2005

The increasing emission of greenhouse gases may change agricultural environment. The agronomic productivity will depend upon change of temperature, precipitation, solar radiation and fertilization. This study was conducted to investigate greenhouse gas emission with irrigation water depth in paddy field. Area of each experiment plot is $70m^2$, Three treatments with three replications were carried out in this experiment, which was laid out as randomized complete block design. The treatments of irrigation water were maximum field water capacity and 4 and 8 cm depth. The application rate of fresh rice straw was $8,000kg\;ha^{-1}$ in combination with chemical fertilizers ($110kg\;N\;ha^{-1}$, $45kg\;P_2O_5\;ha^{-1}$ and $57kg\;K_2O\;ha^{-1}$). The $CH_4$ emission was highest at 32 days after rice transplanting with rice straw treatment. The $CH_4$ emission in the plot of maximum field water capacity was lower compared with 4 and 8 cm of irrigation depth. $CH_4$ and $N_2O$ emission under different water depth in the paddy field were 30 and $1.52kg\;ha^{-1}$ at 8 cm depth, 281 and $1.71kg\;ha^{-1}$ at 4 cm depth, and 219 and $2.01kg\;ha^{-1}$ at water saturated condition. The total emission of greenhouse gases equivalent to $CO_2$ emission with rice straw application were $6,939kg\;CO_2\;ha^{-1}$ at 8 cm depth plot, $6,431kg\;CO_2\;ha^{-1}$ at 4 cm depth plot and $5,222kg\;CO_2\;ha^{-1}$ at water saturated condition. The GWPs without rice straw application were $4,449kg\;CO_2\;ha^{-1}$ at 8 cm depth plot, $3,702kg\;CO_2\;ha^{-1}$ at 4 cm depth plot and $4,579kg\;CO_2\;ha^{-1}$ at water saturated condition.

• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.2
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• pp.135-141
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• 2005

Nitric oxide(NO) reduction by methanol was investigated over $La_2O_3$ catalysts in the presence and absence of oxygen. In the absence of $O_2$, $CH_3OH$ reduced NO to both $N_2$ and $N_2O$, with selectivity to $N_2$ formation decreasing from 81-88% at 623K to 47-71% at 723 K. With 1.2% $O_2$ in the feed, the rates were 4-8 times higher, but the selectivity to $N_2$ dropped from 50% at 623 K to 9% at 723 K. The specific activities with $La_2O_3$ for this reaction were higher than those for other reductants; for example, at 773 K with hydrogen a specific activity of $34\;{\mu}mol\;NO/sec{\cdot}m^2$ was obtained whereas that for methanol was $638\;{\mu}mol\;NO/sec{\cdot}m^2$. The Arrhenius plots were linear under differential reaction conditions, and the apparant activation energy was consistantly near 15 kcal/mol with $CH_3OH$. Linear partial pressure dependencies based on a power rate law were obtained and showed a near-zero order in $CH_3OH$ and a near-first order in $H_2$.

• Korean Journal of Soil Science and Fertilizer
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• v.37 no.6
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• pp.388-395
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• 2004

This study was carried out to determine the application rate of pig slurry for red pepper. Field experiment was designed with non-fertilizer, chemical fertilizer recommended by soil testing (CFRST) and pig slurry treatments. In pig slurry (PS) plots, pig slurry was applied as basal fertilizer with different equivalents to nitrogen of chemical fertilizer plot (60%: PS60, 80%: PS80, 100%: PS100, 120%: PS120) and chemical fertilizer was top-dressed additionally. Soil organic matter contents after 50 day of planting and after experiment in the plots treated with PS were higher than that of CFRST plot, whereas content of $NO_3-N$ of CFRST plot was higher than that of PS plot. Growth of red pepper were lowest in the non-fertilizer plot. Plant lengths of red pepper at 50 day after planting were similar among the different treatments, plant lengths of red pepper of PS100, PS120 and CFRST at 100 day after planting were higher than those of the PS60 and PS80 plots. But Main stem and stem diameter of red pepper were not different among the treatments. Uptake rate of N, P and K by red pepper plant were 27-44, 9-16 and 41-68% for total N, $P_2O_5$ and $K_2O$, respectively. Utilization of applied fertilizer ingredient by red pepper plant were in the order of PS80> PS60> FRST> PS100> PS120. Yield of red pepper tends to increase by 3% in the PS100 compared with the CFRST, but there was not significant difference between PS120 and CFRST. Chemical component of run-off collected from the furrow of the red pepper field was not different among the treatments. Greenhouse gases ($CH_4$ and $N_2O$) emission of non-fertilizer, PS100 and CFRST during the whole red pepper growth period were 4.0, 4.8 and $5.9kg\;CH_4\;ha^{-1}$, and 0.74, 6.68 and $8.38kg\;N_2O\;ha^{-1}$. Emission of $CH_4$ and $N_2O$ in PS100 was higher than those of CFRST by 23% and 26%, respectively. In this connection, to be used the pig slurry for red pepper, it is required that pig slurry must be decomposed for six months or more. Consequently, pig slurry equivalent to nitrogen of basal fertilizer of CFRST with additional top dressing of chemical fertilizer is recommend as an optimum application rate of pig slurry for red pepper.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.10b
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• pp.143-144
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• 2002

A series of alcohols with perfluorinated segments $F(CF_2)_m(CH_2)_n-OH$, with m=8, 10 and n=4, 6, 10, were synthesized. First, the alcohols were reacted with fatty acid to produce several esters $(F(CF_2)_m(CH_2)-OOC-R$ with m=8, 10 and n=2, 4, 8,) containing perfluoro group by condensation reaction, and characterized by FT-IR, GC, and surface tension. The esters were soluble in ethyl ether, toluene, hexane, ethyl acetate, chloroform, and acetone, but insoluble in methyl alcohol, ethyl alcohol and isopropyl alcohol. Preliminary experiments on 1,2-dichloroethane solutions showed a remarkable decrease of surface tension upon addition of the esters. Also, the esters films ranged from 100 to $122^{\circ}$, depending on the structure of fatty acid esters. As the separate experiment, the water-repellency of coated paper and cotton was evaluated. As a result, the water droplet dropped in surface was not permeated for two weeks.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.51 no.4
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• pp.175-183
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• 2002

In this paper, the surface modification effect of self-assembled monolayer(SAM) of 1-dodecanethiol [$CH_3$($CH_2$)$_{11}$SH] used as an anti-adhesive film in micromolding process was studied. Monolayers of 1-dodecanethiol[$CH_3$(CH$_2$)$_{11}$SH] were obtained by immersing a metal place in pure 1-dodecanethiol. SAM film on the nickel plate has been examined by using X-ray photoelectron spectroscopy(XPS). The focus has been placed on S-Ni bonding. From the XPS analysis, sulfur atoms were detected from the SAM film as a chemical composition of S-Ni. In order to measure an adhesion force of the SAM-coated nickel surface, atomic force microscopy(AFM) was used in force-distance mode, which whows the micro-adhesive force on solid surface. It was shown that adhesion forces measured from the SAM-coated nickel surface and the Ni surface without SAM coating were 3.52nN and 5.32nN, respectively. In order to investigate the effect of SAM coating on the surface foughness the replica in demolding process, hot embossing experiments were performed using a SAM-coated nickel master and a nickel master without SAM coating. Surface roughness of replica from the SAM-coated master showed 25nm and that of replica from master without SAM coating was 35nm. The smoother surface roughness of the replica from the SAM-coated, master is believed to result from reduction in the adhesion forces.ces.

• Journal of The Korean Society of Agricultural Engineers
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• v.60 no.1
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• pp.79-87
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• 2018

Water management impacts both methane ($CH_4$) and nitrous oxide ($N_2O$) emissions from rice paddy fields. Although irrigation is one of the most important methods for reducing $CH_4$ emission in rice production systems it can also $N_2O$ emissions and reduce crop yields. A feasibility study on the system of rice intensification (SRI) methods with respect to irrigation requirements, greenhouse gas (GHG) emissions was conducted for either 2 or 3 years depending on the treatment in Korea. The SRI methods (i.e. SRI and midsummer drainage (MD) with conventional practice (CT)) reduced the irrigation requirement by 49.0 and 22.0 %, respectively. Global warming contribution of GHG to different depending on the type of GHG. Therefore, the emission of $CH_4$ and $N_2O$ shall be converted to Global Warming Potential (GWP). The GHG emission from the conventional practice with midsummer drainage (MD) and the SRI plots, in GWP were reduced by 49.1 and 77.1 %, respectively. Application of SRI water management method could help to improve Korea's water resources and could thus contribute to mitigation of the negative effects of global warming.