• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.4
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• pp.68-75
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• 2018

The introduction of advanced water treatment facilities has increased as the conventional purification method cannot remove the substance clearly. However, the internal waterproofing and Anticorrosion materials of the advanced water treatment facility using ozone deteriorate due to the oxidation power of ozone and affects the concrete, which causes a decrease in durability. This study is to evaluate the ozone resistance according to the type of spray metal and the surface treatment method of the coating, and the bond strength after ozone treatment in order to develope a finishing method to prevent deterioration of concrete structure of water treatment facility using metal spraying method as a way to construct metal panel with excellent ozone resistance and chemical resistance by an easier way than the previous. The Experimental results show that spray metal Ti has superior ozone resistance even after spraying. It is considered to be the most suitable method for ozone resistance and bond performance by finishing using Teflon sealing as surface treatment method.

• Journal of the Korean Chemical Society
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• v.35 no.3
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• pp.275-279
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• 1991

Ultra-fine alumina, ${\alpha}-Al_2O_3$, with ${\phi}$ = 0.1∼0.5 ${\mu}$m was obtained from pure ammonium aluminum sulfate(alum) as the thermal decomposition product. Pure alum(> 99.7%) could be prepared by the precepitation and the successive recrystallization in an acidic aqueous solution at pH = 1.5∼2.5, which was theoretically predicted by only considering the concentrations of hydroxide and carbonate for aluminum and sodium in the solution, and also experimentally confirmed as the optimum precepitation condition for alum without forming any impurities like aluminum hydroxide or sodium one.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.403-404
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• 2013

최근 scaling down의 한계에 부딪힌 DRAM과 Flash Memory를 대체하기 위한 차세대 메모리(Next Generation Memory)에 대한 연구가 활발히 진행되고 있다. ITRS (international technology roadmap for semiconductors)에 따르면 PRAM (phase change RAM), RRAM (resistive RAM), STT-MRAM (spin transfer torque magnetic RAM) 등이 차세대 메모리로써 부상하고 있다. 그 중 RRAM은 간단한 구조로 인한 고집적화, 빠른 program/erase 속도 (100~10 ns), 낮은 동작 전압 등의 장점을 갖고 있어 다른 차세대 메모리 중에서도 높은 평가를 받고 있다 [1]. 현재 RRAM은 주로 금속-산화물계(Metal-Oxide) 저항 변화 물질을 기반으로 연구가 활발하게 진행되고 있다. 하지만 근본적으로 공정 과정에서 산소에 의한 오염으로 인해 수율이 낮은 문제를 갖고 있으며, Endurance 및 Retention 등의 신뢰성이 떨어지는 단점이 있다. 따라서, 본 연구진은 산소 오염에 의한 신뢰성 문제를 근본적으로 해결할 수 있는 다양한 금속-질화물(Metal-Nitride) 기반의 저항 변화 물질을 제안해 연구를 진행하고 있으며, 우수한 열적 안정성($>450^{\circ}C$, 높은 종횡비, Cu 확산 방지 역할, 높은 공정 호환성 [2] 등의 장점을 가진 WN 박막을 저항 변화 물질로 사용하여 저항 변화 메모리를 구현하기 위한 연구를 진행하였다. WN 박막은 RF magnetron sputtering 방법을 사용하여 Ar/$N_2$ 가스를 20/30 sccm, 동작 압력 20 mTorr 조건에서 120 nm 의 두께로 증착하였고, E-beam Evaporation 방법을 통하여 Ti 상부 전극을 100 nm 증착하였다. I-V 실험결과, WN 기반의 RRAM은 양전압에서 SET 동작이 일어나며, 음전압에서 RESET 동작을 하는 bipolar 스위칭 특성을 보였으며, 읽기 전압 0.1 V에서 ~1 order의 저항비를 확보하였다. 신뢰성 분석 결과, $10^3$번의 Endurance 특성 및 $10^5$초의 긴 Retention time을 확보할 수 있었다. 또한, 고저항 상태에서는 Space-charge-limited Conduction, 저저항 상태에서는 Ohmic Conduction의 전도 특성을 보임에 따라 저항 변화 메카니즘이 filamentary conduction model로 확인되었다 [3]. 본 연구에서 개발한 WN 기반의 RRAM은 우수한 저항 변화 특성과 함께 높은 재료적 안정성, 그리고 기존 반도체 공정 호환성이 매우 높은 강점을 갖고 있어 핵심적인 차세대 메모리가 될 것으로 기대된다.

• Applied Biological Chemistry
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• v.17 no.4
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• pp.235-239
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• 1974

Rice root activiators (phthalamic acid (PA) and p-chlorophenyl PA (PCPPA) were tested in pot culture for their effects on yield of IR667-Suwon 214 weak in root activity. The results were as follows: 1) Maximum percentage yield increase was 36.7% with organic matter applied and 13.3% without organic matter in 100 ppm (90ml/0.05$m^2$) of PCPPA treatment. 2) Root activators increased oxidizing power of root (root activity), consequently gave a balanced nutrient uptake, stimulated root growth and subsequent shoot growth. 3) Root activators increased number of panicle per hill, grain weight, filled grain ratio and effective tiller ratio.

• Journal of the Korean Society for Railway
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• v.13 no.6
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• pp.565-569
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• 2010

Sleepers perform bearing rails and are underneath rails. Therefore, the current and voltage of rails are related to the resistance of sleepers. In case that the resistance of sleepers are low, operation problems of relays in tr ack circuits are occur because of flowing leakage current through sleepers. So the condition that the track circuit is always occupied by a train is kept. Currently, the creosote has been used in wood sleepers due to prevention against putrefaction. After a long time, the material is changeable to the chemistry material bases on carbon dioxide or carbon. So, the insulation resistance of wood sleepers is lower than the initial insulation resistance. In case of effecting wood sleepers as conductors, amplitude of the current and voltage on rails is decreased. This phenomenon causes that a train does not receive signals. In this paper, four-network model on the track circuit including the insulation resistance of sleepers is suggested. Also, the standard value of the resistance in straight section is proposed in the wood sleeper.

• Journal of the Korean Chemical Society
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• v.18 no.5
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• pp.373-380
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• 1974

Direct electrochemical preparation of periodate from iodide $(I^-{\to}{IO_4}^-)$ was investigated using a none-diaphragm cell and lead dioxide anode. The direct electrolytic conditions were combinations of the respectively results on the processes of iodate from iodide$(I^-{\to}{IO_3}^-)$, and periodate from iodate$({IO_3}^-{\to}{IO_4}^-)$ which were reported by the author, previously. The optimum condition was achieved when 1.0 M potassium iodide solution containing 0.5 g/l potassium dichromate as an anti-reducing agent was electrolyzed at anodic current density of $15{\AA}/dm^2$ and electrolytic temperature of $60^{\circ}C$. Under such a condition, the current efficiency was found to be 84 % at 98 % conversion of iodide to periodate. The explanation of electrode reaction was also given a consideration based on the polarization curves at lead dioxide anode in various electrolyte solutions.

• Journal of the Korean Home Economics Association
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• v.24 no.4
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• pp.87-92
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• 1986

In Order to study antioxidative action of water soluble fractions which had been steamed according to time as 15, 30, 60 and 120 minutes, they were compared through the inhibitory effect of lipoperoxide formation by TBA, peroxide value and induction time for the first period of lipoperoxide formation. Results are obtained as follows: 1. In vivo experiment with TBA value, water soluble fractions showed aninhibitory effect of lipoperoxide formation. 2. Comparing with the inhibitory effect of lipoperoxide formation with TBA value in vivo, water soluble fractions which had been steamed for 30 and 60 minutes and those from fresh garlic proved effective in the blood by intraperitoneal administration. But in the liver all of water soluble fractions showed distinctive effect as in the case of fresh garlic. 3. Effect of water soluble fractions which had been steamed for 15, 30 and 60 minutes showed a distinctive effect, water soluble fraction which had been steamed for 120 minutes and that from fresh garlic also showed effective in the blood as compared with control. 4. In oral administration, water soluble fraction of fresh garlic was the most effective in the liver. 5. In vitro experiment with peroxide value, water soluble fractions which had been steamed for 60 and 120 minutes were effective, all of water soluble fractions from steamed garlic were more effective than fresh garlic. 6. In Examining the induction time for the first period of lipoperoxide formation in vitro, water soluble fractions steamed for 30, 60 and 120 minutes were effective. Other fractions were also more effective than control.

• Journal of the Korean GEO-environmental Society
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• v.11 no.5
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• pp.15-23
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• 2010

Dry sieving, wet sieving and photoscattering analyzer were tested as particle size analyzing methods for sediments from rivers and lakes of Han river, Nakdong river, Youngsan river, and Kumgang river area. Dry sieving showed a big error due to coagulating effect over drying process and this phenomena was severe for lake sediment. Wet sieving and PSA showed an accurate results though wet sieving needs more labor and complicate processes. Freeze-dry or freeze-dry after oxidation of organics with hydrogen peroxide showed improved results but gave lower portion of fine particles in comparing with wet sieving. Heavy metal contents and extractable metal contents were investigated for the sediments and high heavy metal content and extractable amount were obtained from fine particles as expected. Using of proper particle size analyzing method is important and the sediment management should be focused on the fine particles.

• Korean Chemical Engineering Research
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• v.53 no.3
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• pp.401-406
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• 2015

Getter is a class of materials used in absorbing gases such as hydrogen and moisture in microelectronics or semiconductor devices to operate properly. In this study, we developed a new device structure consisting of porous anodized alumina films on textured silicon wafer, which have cost efficiency in materials and processing aspects. Anodic aluminum oxide (AAO) with controlled pore sizes can be applied to a high-efficiency moisture absorber due to the high surface area and OH- saturated surface property. The moisture sorption capacity was 2.02% (RH=35%), obtained by analyzing isothermal adsorption/desorption curve.

• Korean Journal of Materials Research
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• v.10 no.11
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• pp.749-764
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• 2000

Amorphous TaSiN thin films of about 90 nm thick were deposited onto poly-Si and $SiO_2/Si$ substrates by rf magnetron sputtering method. TaSiN films exhibited amorphous phase with no crystllization up to $900^{\circ}C$ in oxygen ambient. The penetration depth of oxygen diffusion increased with increasing annealing temperature in oxygen ambient and reached 20 nm deep in a $Ta_{23}Si_{29}N_{48}$ layer at $600^{\circ}C$ for 30min. The resistivity of as-deposited $Ta_{23}Si_{29}N_{48}$ thin films was about $1,300{\mu}{\Omega}-cm$, however those of annealed films markedly increased above $700^{\circ}C$ in oxygen ambient as the annealing temperature increased.