• Journal of the Korean Wood Science and Technology
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• 제19권4호
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• pp.80-84
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• 1991

Lignocellulosic biomass including acetosolv ricestraw and spruce lignin were liquefied and converted into liquid hydrocarbons by catalytic hydroliquefaction reaction. These experimental works were carried out in 1-liter-capacity autoclave using 50% tetralin and m-cresol solution respectively as soluble solvent and Ni. Pd. Fe and red mud as catalyst. $H_2$ gas was supplied into the reactor for escaltion of deoxhydroenolysis reaction. Catalyst concentrations were 1 % of raw material based on weight. The ratio between raw materials and soluble solvent are 1g and 10cc. The reaction conditions are 400-$700^{\circ}C$ of reaction temperature, 10-50 atms of reaction pressure. The highest yield of hydrocarbon, so called "product oil" showed 32% and 5.5% of lowest char formation when red mud was used as catalyst. The product oil yields from those of other catalysts were in the range of 20-29%. The influence of different initial hydrogen pressures was examined in the range d 30-50 atms. A minimum pressure of 35 atms was necessary to obtain a complete recovery of souble solvent for recycling.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제40회 동계학술대회 초록집
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• pp.351-351
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• 2011

Graphene has drawn great interests because of its distinctive band structure and physical properties[1]. A few of the practical applications envisioned for graphene include semiconductor applications, optoelectronics (sola cell, touch screens, liquid crystal displays), and graphene based batteries/super-capacitors [2-3]. Recent work has shown that excellent electronic properties are exhibited by large-scale ultrathin graphite films, grown by chemical vapor deposition on a polycrystalline metal and transferred to a device-compatible surface[4]. In this paper, we focussed our scope for the understanding the graphene growth at different conditions, which enables to control the growth towards the application aimed. The graphene was grown using chemical vapor deposition (CVD) with methane and hydrogen gas in vacuum furnace system. The grown graphene was characterized using a scanning electron microscope(SEM) and Raman spectroscopy. We changed the growth temperature from 900 to $1050^{\circ}C$ with various gas flow rate and composition rate. The growth condition for larger domain will be discussed.

• 한국표면공학회지
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• 제42권3호
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• pp.139-144
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• 2009

A microwave plasma torch at the atmospheric pressure by making use of magnetrons operated at the 2.45 GHz and used in a home microwave oven has been developed. This electrodeless torch can be used to various areas, including industrial, environmental and military applications. Although the microwave plasma torch has many applications, we in the present work focused on the microwave plasma torch operated in pure steam and several applications, which may be used in future and right now. For example, a high-temperature steam microwave plasma torch may have a potential application of the hydrocarbon fuel reforming at one atmospheric pressure. Moreover, the radicals including hydrogen, oxygen and hydroxide molecules are abundantly available in the steam torch, dramatically enhancing the reaction speed. Also, the microwave plasma torch can be used as a high-temperature, large-volume plasma burner by injecting hydrocarbon fuels in gas, liquid, and solid into the plasma flame. Finally, we briefly report treatment of soils contaminated with oils, volatile organic compounds, heavy metals, etc., which is an underway research in our group.

• Nuclear Engineering and Technology
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• 제33권2호
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• pp.145-155
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• 2001

This simulation first allows us to define a transition zone from a bubble to jet mode of the argon out-flow and hereinafter to define a similar area for water-steam leak in the KALIMER SG (Korea Advanced Liquid Metal Reactor Steam Generator) using a water mock-up system, taking into account the KALIMER leak classification and tube bundle design, as a simulation of a real water-steam into sodium leak. in accordance with leak conditions in the KALIMER SG, the transition from bubbling to jetting is studied by means of turbulence regime simulation for argon out-flow through a very small orifice, which has the equivalent diameter of about 0.253 mm. finally the noise generation mechanism is explained from the existing experimental data. We also confirmed the possibility of micro-leak detection from the information of the bubbling mode through simulations and the experiment in this study.

• KSBB Journal
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• 제30권4호
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• pp.161-165
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• 2015

Lactic acid and its derivatives are widely used in the food, pharmaceutical, and cosmetic industries. It is also a major raw material for the production of poly-lactic acid (PLA), a biodegradable and environmentally friendly polymer and a possible alternative to synthetic plastics derived from petroleum. For PLA production by new strains of lactic acid bacteria (LAB), we screened LAB isolates from shellfish. A total of 51 LAB were isolated from 7 types of shellfishes. Lactic acid production of individual isolates was examined using high-performance liquid chromatography using a Chiralpak MA column and an ultraviolet detector. Lactobacillus plantarum T-3 was selected as the most stress-resistant strain, with minimal inhibition concentrations of 1.2 M NaCl, 15% ethanol, and 0.0020% hydrogen peroxide. In a 1 L fermentation experiment, $\small{D}$-lactic acid production of 19.91 g/L fermentation broth was achieved after 9 h cultivation, whereas the maximum production of total lactic acid was 41.37 g/L at 24 h.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2004년도 제22회 춘계학술대회논문집
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• pp.34-40
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• 2004

Two different type scramjet models with side-wall compression and top-wall compression inlets have been tested in HPTF (Hypersonic Propulsion Test Facility) under the experimental conditions of Mach number 5.8, total temperature 1700K, total pressure 4.5㎫ and mass flow rate 3.5kg/s. The liquid kerosene was used as main fuel for the scramjets. In order to get fast ignition in the combustor, a small amount of hydrogen was used as a pilot. A strut with alternative tail was employed for increasing the compression ratio and for mixing enhancement in the side-wall compression case. Recessed cavities were used as a flameholder for combustion stability. The combustion efficiency was estimated by one dimensional theory. The uniformity of the facility nozzle flow was verified by a scanning pitot rake. The experimental results showed that the kerosene fuel was successfully ignited and stable combustion was achieved for both scramjet models. However the thrusts were still less than the model drags due to the low combustion efficiencies.

• Food Science and Biotechnology
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• 제16권1호
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• pp.18-22
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• 2007

The objective of this study was to develop and assess the performance of an aseptic system for liquid milk contained in plastic bottles, from a small-scale production standpoint. Commercial sterility tests conducted on the bottled milk were utilized in our assessments of the system, via the identification and monitoring of the principal points of the process. Four 150 L batches of milk with pH values of approximately 6.7 were heat-processed at between 137 and $143^{\circ}C$ for 10 see in a plate heat exchanger, and then aseptically transferred to 500 mL high-density polyethylene (HOPE) bottles, in an ISO class 7 clean room. The aseptic condition of the bottles was achieved via 10 see of rinsing with a mixture containing 0.5% peracetic acid and 0.8% hydrogen peroxide at $30^{\circ}C$, followed by another rinse with sterile water. Of the 4 batches processed, 2 were determined to exhibit commercial sterility, on the basis of the physical-chemical and microbiological criteria adopted. It was concluded that some adjustment of the processing line was required in order to achieve full commercial sterility for all processes. The aseptic system developed and assessed in this study was demonstrated to have great potential for the processing and transferring of milk into plastic bottles, from a small-scale production standpoint.

• 한국균학회지
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• 제22권1호
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• pp.46-49
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• 1994

C. congregatus를 산성 액체배지(pH4.2)에 배앙할 경우 세포막연관 laccase가 배양 초기에 대량 합성분비되었으며 분비된 효소의 작용에 의하여 melanin색소가 중성배지에 비하여 빨리 생성되었고 배양 24시간 후에 배지의 산도는 pH5.2로 증가되었다. 이 효소의 합성은 transcription inhibitor인 5-fluorouracil에 의하여 크게 억제되었다.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.547-548
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• 2006

The main object of this research was to examine the effect of sintering conditions on the microstructure of tungsten heavy alloys and how the resulting modification of the microstructure can be used to optimize their mechanical properties. Alloys composed of 88%, 93% and 95% wt. of tungsten and the balance is Ni: Fe in the ratio of 7:3 were sintered at different temperatures for different sintering holding times in hydrogen atmosphere. It was shown that the mechanical properties of the alloys, and especially their ductility, are harmed when tungsten grains are contiguous.

• Bulletin of the Korean Chemical Society
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• 제19권10호
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• pp.1105-1109
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• 1998

A chiral stationary phase derived from (S)-N-(3,5-dinitrobenzoyl)leucine N-phenyl N-alkyl amide (CSP 2) was applied in separating the two enantiomers of various π-basic aromatic derivatives of leucine N-propyl amide in order to evaluate π-basic aromatic groups as an effective derivatizing group for the resolution of a-amino acids. Subsequently N-(3,5-dimethoxybenzoyl) group was found to be very effective as a π-basic aromatic derivatizing group. Based on these results, N-(3,5-dimethoxybenzoyl) derivatives of various a-amino N-propyl amides, N,N-diethyl amides and esters were resolved on the CSP derived from (S)-N-(3,5-dinitrobenzoyl) leucine N-phenyl N-alkyl amide (CSP 2) and the resolution results were compared with those on the CSP derived from (S)-N-(3,5-dinitrobenzoyl)leucine N-alkyl amide (CSP 1). The enantioselectivities exerted by CSP 2 were much greater than those exerted by CSP 1. In addition, racemic N-(3,5-dimethoxybenzoyl)-a-mino N,Ndiethyl amides were resolved much better than the corresponding N-(3,5-dimethoxybenzoyl)-a-mino N-propyl amides and esters on both CSPs. Based on these results, a chiral recognition mechanism utilizing the π-π donor-acceptor interaction and the two hydrogen bondings between the CSP and the analyte was proposed.