• Korean Chemical Engineering Research
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• v.50 no.6
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• pp.1015-1020
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• 2012

Lignite of low rank coal and petroleum coke of high sulfur content can be high potential energy sources for coal gasification process because of their plentiful supply. The steam gasification of lignite, anthracite, and pet coke has been carried out in both an atmospheric thermobalance reactor and a lab-scale fludized bed reactor (0.02 m i.d. ${\times}$ 0.6 m height). The effects of gasification temperature ($600{\sim}900^{\circ}C$) and partial pressure of steam (0.15~0.95 atm) on the gasification rate and on the heating value of product gas have been investigated. The modified volumetric reaction model was applied to the experimental data to describe the behavior of carbon conversion, and to evaluate kinetic parameters of char gasification. The results shows that higher temperature bring more hydrogen in the product syngas, and thus increased gas heating value. The feed rate of steam is needed to be optimized because an excess steam input would lower the gasification temperature which results in a degradation of fuel quality. The rank of calorific value of the product gas was anthracite > lignite > pet coke. Their obtained calorific value at $900^{\circ}C$ with 95% steam feed were 10.0 > 6.9 > 5.7 $MJ/m^3$. This study indicates that lignite and pet coke has a potential in fuel gas production.

• Transactions of the Korean hydrogen and new energy society
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• v.9 no.4
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• pp.169-176
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• 1998

An experimental study on effect of vapor-cooled heat stations in a 5.5 liter cryogenic vessel has been performed. The cryogenic vessel is made of stainless steel of thickness of 1mm and insulated by the combined insulation of vacuum, MLI(multi-layer insulation) and vapor-cooled radiation shield. Vapor-cooled heat stations are also constructed based on the 1-dimensional thermal analysis to reduce the heat inleak through a filling tube. Thermal analysis indicates that the vapor-cooled heat stations can substantially enhance the performance of vessel for cryogenic fluids with high $C_p/h_{fg}$ where $C_p$ the specific heat and $h_{fg}$ the heat of vaporization, such as $LH_2$ and LHe. The experimental results for $LN_2$ shows that the total heat inleak into inner vessel consists of 14% radiation and 86% conduction through the filling tube. Therefore, it is expected that the conduction heat in leak of the vessel for high $C_p/h_{fg}$ cryogenic fluids can be significantly reduced. powders. The amount of copper coating was 20wt%. In order to examine corrosion behavior of the electrodes, the corrosion current and the current density, in 6M KOH aqueous solution after removal of oxygen in the solution, were measured by potentiodynamic and cyclic voltamo methods. The results showed that Co in the alloy increased corrosion resistance of the electrode whereas Ni decreased the stability of the electrode during the charge-discharge cycles. The electrode used Si sealant as a binder showed a lower corrosion current density than the electrode used PTFE and the electrode used Cu-coated alloy powders showed the best corrosion resistance.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.46 no.1
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• pp.31-42
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• 2020

Horse fat is known to be an effective ingredient in Asia, and the horse fat itself, which is mixed with other ingredients at the additive level, is often sold as a finished product. In this case, physical properties of the horse fat raw material are important. Many horse fats produced in Korea (Jeju) have low temperature stability, so if not stored at low temperatures, segregation may occur. In the case of Japanese horse fat, it is partially hydrogenated or is used the solid phase as the horse fat by separating the liquid phase and the solid phase that is harder and more stable than the horse fat of Jeju. In this study, the physical properties were tested to improve the temperature stability even without the partial hydrogenation process of Jeju horse fat. Various oil gelling agents were used in the study. Results confirmed that the physical properties of the hydroxystearic acid added Jeju horse fat were improved. In addition, stability evaluations at temperatures of 25 ℃, 40 ℃, 45 ℃ and flow behavior evaluations at temperatures of 25 ℃, 30 ℃, 40 ℃ were performed for Jeju horse fat with hydroxystearic acid, 100% Jeju horse fat, and 100% Japanese horse fat. Results showed that the Jeju horse fat improved in flow behavior by adding hydroxystearic acid similar to that of Japanese horse fat. In addition, when the crystal state was observed under a microscope, the thermal stability was improved by decreasing the size of the needle-type crystals with the addition of hydroxystearic acid. Jeju horse fat containing hydroxystearic acid was found to have no physical problems even when stored at room temperature for a long time.

• Polymer(Korea)
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• v.39 no.1
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• pp.78-87
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• 2015

With aiming to prepare microcapsules having a particle size of $30-50{\mu}m$, thermally expandable capsules with relatively uniform particle sizes consisting of a n-octane/poly(acrylonitrile-co-methyl methacrylate) core/shell structure were synthesized using SPG membrane emulsification and suspension polymerization. Four steric stabilizers and five crosslinking agents were employed. When poly(vinyl alcohol) as a stabilizer was used, the prepared capsules showed a smooth and regular morphology and the liquid hydrocarbon (n-octane) was well encapsulated in the core. When 1,4-butnaediol methacrylate (BDDMA) was used as a crosslinker, the uniform capsules with the average diameter of $36.8{\mu}m$ were synthesized. The capsules prepared with 0.05 mol% BDDMA showed the best encapsulation efficiency.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.8
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• pp.1022-1027
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• 2011

A diesel engine works in high compression ratio due to injection of diesel fuel after compression of air. Therefore the engine has a high thermal efficiency, while nitrogen oxide is produced a lot in high flame temperature regions. In order to solve the problem this study HHO gas is added into the intake air of the industrial diesel engine. The test conditions are loads of 0%, 50% and 100% and engine speeds of 700 to 1900 rpm. The results show the maximum torque and pressure is increased, fuel consumption, smoke and CO emissions are decreased and NOx emission is remained at same level.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.10
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• pp.862-871
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• 2012

The numerical simulations on 500-N class rocket engine using 96% hydrogen peroxide and kerosene have been conducted, considering atomization, evaporation, mixing and combustion of its propellants. The grid containing 1/6 part of combustion chamber has been generated and it is assumed that 3 kinds of liquid-phase propellants (kerosene, hydrogen peroxide and water) were injected as hollow cone spray pattern, using Rosin-Rammler function for distribution of droplet diameter. For the calculation of combustion the eddy-dissipation model was applied. Owing to small size of combustion chamber and large specific heat / latent heat of hydrogen peroxide and water the propulsion characteristics were highly influenced by the size of droplet particles, and in this analysis the engine with droplet particles of 30 micron in average has shown the best propulsion performance.

• Clinical and Experimental Reproductive Medicine
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• v.9 no.1_2
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• pp.43-53
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• 1982

여성의 난소기능은 뇨중 Oestrone-3-glucuronide를 간편한 solid-phase 의 화학발광성 면역학적 측정법 (Chemiluminescence Imrnunoassay(CIA) 에 의하여 그 기능이 탐지될 수 있다. Oestrone-3-g1ucuronyl-6-bovine serum albumine에 대한 antiserum의 IgG fraction은 polystyrene 실험관벽에 흡착시켰으며, 항원으로서는 est r one-3- gl ucuronyI-6-aminoethyl-ethyl-isoluminol 을 항원 (antigen) 에 labeI 시킨 것이다. 시험 대상물인 뇨는 매일아침뇨(early morning urine) 을 희석 (1:1000 V/V)한 후 100mcl 를 취하여 이를 각기 이중분석액으로 택하였다. 시험관 내에서 결합반응 (1 hour at $4^{\circ}C)이 일어난 후에는 시험관내의 액체를 전부 흡입 폐기시켰으며, 항체반응이 일어난 후 ( antibody-bound fraction )에는 완충액 (400mcl)으로 한번 세척시켰다. 그후 염화수산화물(2N , 200mcl)을 가지고 $22^{\circ}C$에 60 분간 방치 혼합케 한 후 효소(microperoxidase) 와 과산화수소를 가하면서 산화작용에서 발생되는 발광양을 10초동안 측정하여 그 결과를 분석하였다. 위에 기술한 분석방법을 평가하면 다음과 같은 결론을 얻었다. Calibration curve sensitivity$3.12{\pm}0.75$ PG/tube ($mean{\pm}SD$)였고, lntra-assay precision(CV%) 9.52 (20 replicates;$38.4{\pm}3.66$nmol/1) 와 8.81 (15 replicates; $102.4{\pm}8.82$nmol/1)였다. Inter-assay precision(CV%) 은 11.9 (mean of 4 pools-7.03, 23.16, 52.11 과 117.53 nmol/1)로 2개월 동안에 걸쳐 시행되었고, 평균 비이어스(mean bias)는 -0.78 로 28에서 448 nmol 범위로서 매일아침 "뇨"의 차이분(different aliquots)은 좋은 결과를 얻었다. 건강한 여성으로부터 채취된 뇨중 Oestrone-3-glucuronide 의 농도(nmol/1)를 보면 월경주기의 여포기와 배난기 및 황체기에 있어서 각기 $40.2{\pm}9.9$ , $102.3{\pm}39.4$와 $84.3{\pm}13.3$nmol/1였다. 이와같은 결과는 동일한 검사뇨를 방사면역학적 방법(RIA)으로 측정 (6 menstrual cycle)한 결과와 유사한 측정치를 얻으므로서 간편하고 진보된 좋은 방법중의 하나라고 사료되는바이다.

• Journal of the Korean Society of Propulsion Engineers
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• v.16 no.1
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• pp.36-44
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• 2012

Multi-injector rocket engine using high-concentrated hydrogen peroxide and kerosene was designed and manufactured. Design requirements of a rocket engine were determined and main geometrical parameters of rocket engine were determined on the basis of fundament. Six coaxial swirl injectors were mounted on the multi-injector engine. Flow analysis in the hydrogen peroxide manifold was performed to minimize stagnation and recirculation zones. Finally, the optimized hydrogen peroxide manifold was manufactured and cold flow test was carried out to confirm mass flow rate per uni-element, spray pattern and atomization characteristics. The results of cold flow test showed that the mixing head design process was successful and enough to use as a essential database for the development of a full-scale engine.

• Journal of Korea Soil Environment Society
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• v.1 no.1
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• pp.19-27
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• 1996

Nonaqueous phase liquids(NAPL) not readily dissolved in water exist as a separate fluid phase. Groundwater contamination by NAPL such as organic solvents and petroleum hydrocarbons becomes major public concerns because of their long-term persistence in the subsurFace and their ability to contaminate large volumes of wate. Dense.-than-water NAPL(DNAPL) spilled into the subsurface penetrate through the saturated zone and ultimately form DNAPL pools on the bottom of the aquifer. The dissolution of DNAPL from these pools depends on the molecular diffusion coefficient, the vertical dispersivity, the groundwater velocity, the solubility, and the pool length. In this study, the vertical transverse dispersion coefficients for simulating the dissolution of DNAPL from such pools were obtained from the dissolution experiment. Under the experimental conditions used, the vertical transverse dispersion coefficients calculated were 1.86$cm^2$/day, 2.90$cm^2$/day and 4.51$cm^2$/4ay for seepage velocities of 59.2cm/day, 94.3cm/day and 158.0cm/day, respectively. And the vertical transverse dispersivity was 0.03024cm.

• Analytical Science and Technology
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• v.8 no.2
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• pp.139-159
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• 1995

Positive ion mass spectra of some corticosteroids were obtained by using liquid chromatography-mass spectrometry(LC-MS). The base peak of each compound showed the protonated molecular ion [$MH^+$], ammonium adduct ion [${MNH_4}^+$] or [$MH^+-60$] ion according to its chemical structure and other characteristic mass ions were [$MH^+-18$], [${MNH_4}^+-18$] and so on. Several rat urinary metabolites of methylprednisolone acetate after the oral administration were detected by the thermospray LC-MS. The identified major metabolites were 20-hydroxymethylprednisolone(20-HMP), methylprednisolone(MP) and methylprednisone(11-KMP), which were supposed to be formed by deacetylation at the position of C-21, reduction at C-20, oxidation at C-11, or due to the bond cleavage between C-17 and C-20.