• Korean Journal of Soil Science and Fertilizer
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• v.21 no.2
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• pp.169-175
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• 1988

A laboratory experiment was conducted to investigate the effects of pH, organic matters and anion on the adsorption and degradation of surfactant by different soils; Anmi series (limestone region), Gangseo series (alluvial soil). For this study, Alkyl Benzene Sulfonate (ABS ; Sodium Dodecylbenzenesulfonate) was used as a surfactant. The results were as follows: 1. Adsorption of ABS by soils was correlated positively with the equilibrium concentration of ABS in a soil suspension. (Anmi seris : r=0.9855, Gangseo series : r=0.9931). 2. Adsorption rate of ABS by soils was about 70% of the treated concentration ($600{\mu}g$ ABS/g soil) in a range of pH 4 to pH 5, and about 20% for pH 8. 3. Addition of electrolytes increased ABS adsorption by soils in a soil suspension; the higher concentration, the higher adsorption. But the influence among electrolytes was not significant. 4. Adsorption of ABS by soils was not affected by soil organic matter content in this experiment. 5. Degradation rate of ABS in a soil suspension was about 85% at $30^{\circ}C$, and about 10 to 15% at $10^{\circ}C$. Addition of sewage accelerated the degradation rate regardless of temperature and reached about 85% in a week.

• Journal of the Korean Magnetics Society
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• v.10 no.1
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• pp.30-36
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• 2000

SmCo films were deposited on Si(100) substrate by a Nd-YAG pulsed laser ablation of the targets of Sm$\_$100-x/Co$\_$x/ (73$\leq$x$\leq$93) at the substrate temperature of 600∼700$\^{C}$ and the laser beam energy density of Q switching mode or fixed Q mode. The magnetic properties of the films obtained from the Q switching mode exhibited a 4 $\pi$ Ms of 5200∼7700 Gauss, iHc of 190-250 Oe, and 4$\pi$M$\_$r//4$\pi$M$\_$s/ of 0.4∼0.74, respectively, while the fixed Q mode gave the magnetic properties of corresponding films of a 4$\pi$M$\_$r//4$\pi$M$\_$s/ = 0.32∼0.91 and iHc of 430-6290 Oe, respectively. The fixed Q mode gave the better magnetic properties of the SmCo films which seems to be due to a formation of magnetically hard minor phases in droplet of Sm-rich intermetallics. However, the resultant rough surface of the SmCo films is a problem to be solved by a continued study.

• Journal of the Korean Vacuum Society
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• v.10 no.1
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• pp.51-56
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• 2001

$CeO_2$ thin films as insulator for MFISFET (Metal-ferroelectric-insulator- semiconductor-field effect transistor) were deposited by r.f. magnetron sputtering. Ar and $O_2$ gas as the deposition gas were used and the effects of oxygen partial pressure during sputtering on texture and electrical properties of $CeO_2$ thin films were evaluated. All $CeO_2$ thin films deposited on p-type Si(100) substrate at $600^{\circ}C$ exhibited (200) preferred orientation. The films deposited with only Ar gas among various condition had highest preferred orientation but show large hysteresis characteristics in capacitance-voltage measurement due to relatively many charged paricles and roughness. Films show smooth surface state and good C-V characteristics with increasing oxygen partial pressure. It was thought that this trend in C-V characteristics was due to the amount of mobile ionic charge within $CeO_2$ films. The composition of films show oxygen excess, that is, O/$Ce_2$ ratio of films was 2.22~2.42 range and leakage current of films show $10^{-7}~10^{-8}A$order at 100 kV/cm.

• Journal of the Korean Institute of Gas
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• v.22 no.4
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• pp.63-73
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• 2018

Innovative technical process for Energy Storage System (ESS), Liquid Air Energy Storage system (LAES) is mature technologies based on the gas liquefaction process. In spite of many advantages such as high energy density, no geographical constraints, low investment costs and long useful life, the system has not yet widely commercialized due to low round trip efficiency. To improve RTE and acquire high yield of liquid air, various configurations of LAES process have been considered. In this research, dual refrigerants cycle (R-600a and methanol) for air liquefaction and thermal oil circulation for power generation via liquid air gasification have been applied to improve cycle performance significantly using Aspen HYSYS simulator.

• Microbiology and Biotechnology Letters
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• v.39 no.2
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• pp.182-187
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• 2011

In this study, A bacterium with an ability to resist toxic heavy metals was isolated from reeds in wetland. The isolated strain was identified to Alcaligenes sp. KC-1 by 16S rDNA sequencing. Heavy metals such as Pb, $Cr^{6+}$, Cd, Zn and Cu were supplied to media. The ecotoxic treat of the heavy metals on the growth of strain KC-1 was performed when the isolated strain Alcaligenes sp. KC-1 cultured with Cu ranging from 0 mM to 20 mM. It showed the resistance of $EC_{50}$(7.34 mM) and cell growth ($OD_{600\;nm}$ : 0.83 after 42 hours) when it was cultured in Cu.

• Journal of Sensor Science and Technology
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• v.9 no.5
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• pp.357-364
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• 2000

The structural, electrical and gas sensing characteristics of $LaFeO_3$ thin films fabricated by r.f. magnetron sputtering method on $Al_2O_3$ substrates were investigated. (121) domonant crystalline plane was observed for the films heat-treated at above $600^{\circ}C$ and gas sensing properties showed p-type semiconductor behaviors. Gas sensing characteristics of the $LaFeO_3$ thin films was studied as a function of film thicknesses and heat treatment temperatures. While the variation of the film thickness showed a little effect on the sensitivity, the heat treatment temperature was critical to the sensitivity. The thin films with thickness of 400 nm heat-treated at $800^{\circ}C$ showed the sensitivity of 400% for 5000ppm CO and 60% for 350ppm $NH_3$ at the working temperature of $300^{\circ}C$.

• Microbiology and Biotechnology Letters
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• v.39 no.3
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• pp.218-223
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• 2011

To obtain eicosapentaenoic acid (EPA)-producing bacteria, some 600 strains of bacteria were isolated from Antarctic sediment and marine organisms during the summer expedition of 1999-2000 and 7 EPA-producing bacteria were obtained through screening with TLC and GC. A strain designated as L93 showed the highest EPA production, which was gram-negative, rod-shaped bacterium. L93 strain was identified as Shewanella sp., from the sequence analysis of 16S rDNA. Optimal conditions temperature and pH for the growth and EPA production were about $4^{\circ}C$ and pH 7. In addition, its production was optimized by 50%(w/v) sea salt. We establish the optimal production system to produce about 320 mg per liter by using this optimal EPA production conditions. EPA-methyl ester was purified from cultured L93 strain to a purity of higher than 97% and typical purification yield is greater than 72% of the input amount via urea complexation and HPLC.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.10
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• pp.672-678
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• 2014

In this study, variations of fermentative hydrogen production and microbial community were investigated with different nitrogen concentration of food waste. Optimum hydrogen production rate was acquired at 200 mg/L nitrogen concentration of the food waste. Which was eqivalent to 83.43 mL/g dry biomass/hr. However, bio-hydrogen production was inhibitedly reduced at over 600 mg/L of nitrogen concentration whereas proportional relation between hydrogen production and B/A ratio were not observed. Most dominant specie of the microbial community analyzed was Clostridium sp. throughout PCR-DGGE analysis of 16S rDNA. It revealed that most contributing microorganism producing hydrogen were Enterococcus faecium partial, Klebsiella pneumoniae strain ND6, Enterobacter sp. NCCP-231, and Clostridium algidicarnis strain E107 in this experiment.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.25 no.1
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• pp.32-34
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• 2015

AlN Single Crystal were grown by PVT (Physical vapor transport) method on bulk seed. It was performed by high-frequency induction-heating coil. AlN source powder was loaded at bottom side of the carbon crucible and the crystal seed was loaded at the upper side of the crucible. The temperature conditions of the growth was varied $2000{\sim}2100^{\circ}C$ and the surrounding pressure was $1{\times}10^{-1}{\sim}200$ Torr. And the hot-zone of the heating position was controlled elaborately according to growth. The 17 mm-diameter, 7 mm-thickness AlN single crystal is obtained for about 600 hours growing. It was recognized that the growth direction of as grown crystal was R[011] by the Laue X-Ray camera measurement.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2006.05a
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• pp.81-90
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• 2006

The GNUnet proposed a file encoding method by 1KB block size to support anonimity of files, decentralizes encoded block to peers through unstructed mode and original data decoding method a block searching or encoded blocks. but, the encoding and block decentralizing method with $600\sim700MB$ large multimedia file appered two problems. First problem, it need addition R block and I block, which make about 4% of storage resource. Second problem, unstructured model added network load by broadcasting decentralizing method. Third problem, The critical point of keyword search function. This paper suggest variable encoding block size and structured model by block decentralizing solution. Suggested encoding method reduced block request supplementary block generation from 4% to 1%, network load by proposal structured model sending answer through dedicated peer to decentralize block and we defined content-based keyword and identifier of sharing file.