• Journal of Digital Convergence
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• v.13 no.8
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• pp.9-20
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• 2015

To derive a check list of a borrowed city phenomenon, this discussion, through two cities subway OOH advertising in door, compared for convergence by segment analysis. First, discussions considered to be close to the topic of this discussion were arranged and summarized. Seoul and London were selected, and both sides of subway train doors in two cities selected, their states pictured and the images analyzed. As a result of comparison, in case of Seoul subway, the boundary between public information and commercial information(outdoor advertising) was very vague, so the borrowed city phenomenon was very generally analyzed. However, In case of London subway, its result was very contrary to that of Seoul. Eventually, Subway train doors of Seoul city as a borrowed city extracted check points of height, size, color, interval, space and permanency. Therefore in order to study serious discussion this contribution is necessity to limit thoughtless OOH advertising by these checklists in Korean cities.

• Resources Recycling
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• v.13 no.6
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• pp.9-15
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• 2004

The optimum conditions were studied for the preparation of transparent iron oxide with the air oxidation of FeOOH. The FeOOH obtained by mixing NaOH and FeSO$_4$ solution in various conditions such as R(=2NaOH/FeSO$_4$), FeSO$_4$ concentration. reaction temperature and air flow rate. When the FeSO$_4$ increased gradually, the concentration of iron ion in the solution became high. So, particle size increased precipitating Fe$_3O_4$. Goethite dehydrate at about 200$^{\circ}C$ and ended the reaction at about 320$^{\circ}C$ forming hematite. The lower the reaction temperature was, the shorter the particle length of goethite and particle size decreased. When the flow rate of air as an oxidant increased, the amount of dissolved oxygen in the solution increased, which made oxidation rate increased. And then particle size of goethite decreased.

• Corrosion Science and Technology
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• v.6 no.3
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• pp.128-132
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• 2007

For a quantitative inspection on the performance of weathering steel bridges, we have investigated the relationship between the corrosion rate and the composition of the rust layers formed on weathering steel bridges located in various environments in Japan and applied a protective ability index (PAI) to the bridges. The corrosion rates were clearly classified by the PAI, ${\alpha}/{\gamma}*$ and sub index of $({\beta}+s)/{\gamma}*$, where $\alpha$, \gamma*, $\beta$ and s are the mass ratio of crystalline $\alpha-FeOOH$, the total of $\gamma$-FeOOH+ $\beta$-FeOOH + the spinel-type iron oxide (mainly $Fe_3O_4$), $\beta-FeOOH$ and spinel-type iron oxide, analyzed by powder X-ray diffraction, respectively. In the case of ${\alpha}/{\gamma}$*>1, the rust layer works protective enough to reduce the corrosion rate less than 0.01 mm/y. The sub index $({\beta}+s)/{\gamma}*$<0.5 or >0.5 classifies the corrosion rate of the non-protective rust layers, therefore the former state of the rust layer terms inactive and the latter terms active. The quantitative inspection of a weathering steel bridge requires a performance-inspection (PI) and periodical deteriorationinspections (DI). The PI can be completed by checking of the PAI, ${\alpha}/{\gamma}*$. The DI on the weathering steel bridges where deicing salt is sprinkled can be performed by checking the PAI, $({\beta}+s)/{\gamma}*$.

• Journal of the Korean Ceramic Society
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• v.42 no.11 s.282
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• pp.722-728
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• 2005

A wet-chemical route was utilized to obtain nanosized crystalline goethite ($\alpha$-FeOOH) particle, which was known as an oxidation catalyst in reducing carbon monoxide (CO) and dioxine during incineration. A cost-effective $FeSO_4{\cdot}7H_2O$ was used as starting raw material and a successive process of hydrolysis-oxidation was utilized as synthetic method. The effects of the initial $Fe^{2+}$ concentration, hydrolysis time and oxidation period on the crystalline phase and particle characteristics were systematically investigated by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and BET analyses. It was found that the spindle-shaped crystalline $\alpha$-FeOOH particle with the width of 70 nm and the length of 200 nm could be obtained successfully when the initial concentration of 1.5 M, hydrolysis time of 4h, and oxidation period of 10 h, respectively. In addition, it was observed that the spindle-shaped $\alpha$-FeOOH particle consisted of nano-sized primary crystallites of $30\~50\;nm$, which were de-agglomerated into individual particle and successively re­agglomerated into spherical or irregular-shaped agglomerates beyond certain periods in the hydrolysis and oxidation process.

• Korean Journal of Materials Research
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• v.23 no.2
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• pp.104-111
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• 2013

In this study, GaN powders were synthesized from gallium oxide-hydroxide (GaOOH) through an ammonification process in an $NH_3$ flow with the variation of $B_2O_3$ additives within a temperature range of $300-1050^{\circ}C$. The additive effect of $B_2O_3$ on the hexagonal phase GaN powder synthesis route was examined by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Fourier transformation infrared transmission (FTIR) spectroscopy. With increasing the mol% of $B_2O_3$ additive in the GaOOH precursor powder, the transition temperature and the activation energy for GaN powder formation increased while the GaN synthesis limit-time ($t_c$) shortened. The XPS results showed that Boron compounds of $B_2O_3$ and BN coexisted in the synthesized GaN powders. From the FTIR spectra, we were able to confirm that the GaN powder consisted of an amorphous or cubic phase $B_2O_3$ due to bond formation between B and O and the amorphous phase BN due to B-N bonds. The GaN powder synthesized from GaOOH and $B_2O_3$ mixed powder by an ammonification route through ${\beta}-Ga_2O_3$ intermediate state. During the ammonification process, boron compounds of $B_2O_3$ and BN coated ${\beta}-Ga_2O_3$ and GaN particles limited further nitridation processes.

• Transactions of the Korean hydrogen and new energy society
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• v.8 no.2
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• pp.67-78
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• 1997

현재 가장 널리 사용되고 있는 2차 전지는 Ni/cd 전지이며 카드뮴 전극의 사용으로 인해 공해 유발 문제를 가지고 있다. 그에 따라 공해 유발문제가 작은 전지를 제작하고자 하는 연구가 전세계적으로 진행되었고, 결과적으로 NiMH 전지가 개발되었다. 그러나 NiMH 전지에 사용되는 MH 전극은 희토류 토금속을 사용하기 때문에 전극 제작 비용이 비싼 단점을 가지고 있다. 본 실험에서는 자연 중 존재량이 많은 철 화합물을 음극 물질로 이용하여 공해 유발 문제와 제작비용 문제에 대한 대안을 제시하고자 하였다. 전지의 양극 물질은 Kamath에 의해 개발된 ${\alpha}-Ni(OH)_2$의 합성법을 응용, 제작하였다. 제작된 ${\alpha}-Ni(OH)_2/{\gamma}-FeOOH(an)$ 전지의 충 방전 및 전기화학적 특성을 조사하여 보고하였다.

• International Journal of Oral Biology
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• v.32 no.4
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• pp.153-160
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• 2007

The superficial dorsal horn, particularly substantia gelatinosa (SG) in the spinal cord, receives inputs from small-diameter primary afferents that predominantly convey noxious sensation. Reactive oxygen species (ROS) are toxic agents that may be involved in various neurodegenerative diseases. Recent studies indicate that ROS are also involved in persistent pain through a spinal mechanism. In the present study, whole cell patch clamp recordings were carried out on SG neurons in spinal cord slice of young rats to investigate the effects of hydrogen peroxide on neuronal excitability and excitatory synaptic transmission. In current clamp condition, tert-buthyl hydroperoxide (t-BuOOH), an ROS donor, depolarized membrane potential of SG neurons and increased the neuronal firing frequencies evoked by depolarizing current pulses. When slices were pretreated with phenyl-N-tert-buthylnitrone (PBN) or ascorbate, ROS scavengers, t-BuOOH did not induce hyperexcitability. In voltage clamp condition, t-BuOOH increased the frequency and amplitude of spontaneous excitatory postsynaptic currents (sEPSCs), and monosynaptically evoked excitatory postsynaptic currents (eEPSCs) by electrical stimulation of the ipsilateral dorsal root. These data suggest that ROS generated by peripheral nerve injury can modulate the excitability of the SG neurons via pre- and postsynaptic actions.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.05a
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• pp.390-393
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• 2010

The thermal decomposition rate of ammonium perchlorate with 3% of yellow iron oxide, FeOOH was found to be much faster than with red iron oxide, $Fe_2O_3$. By applying yellow and red iron oxide as a burning rate modifier to HTPB/AP propellant, burning rate of the HTPB/AP propellant with yellow iron oxide was shown to be 10 ~ 25% faster than with red iron oxide. There was no special difference in viscosity and hardness buildup of yellow and red oxide added HTPB/AP formulations.

• Journal of Powder Materials
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• v.15 no.2
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• pp.148-155
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• 2008

Nano magnetite particles have been prepared by two step reaction consisting of urea hydrolysis and ammonia addition at certain ranges of pH. Three different concentrations of aqueous solution of ferric ($Fe^{3+}$) and ferrous ($Fe^{2+}$) chloride (0.3 M-0.6 M, and 0.9 M) were mixed with 4 M urea solution and heated to induce the urea hydrolysis. Upon reaching at a certain pre-determined pH (around 4.7), 1 M ammonia solution were poured into the heated reaction vessels. In order to understand the relationship between the concentration of the starting solution and the final size of magnetite, in-situ pH measurements and quenching experiments were simultaneous conducted. The changes in the concentration of starting solution resulted in the difference of the threshold time for pH uprise, from I hour to 3 hours, during which the akaganeite (${\beta}$-FeOOH) particles nucleated and grew. Through the quenching experiment, it was confirmed that controlling the size of ${\beta}$-FeOOH and the attaining a proper driving force for the reaction of ${\beta}$-FeOOH and $Fe^{2+}$ ion to give $Fe_3O_4$ are important process variables for the synthesis of uniform magnetite nanoparticles.

• Food Science and Preservation
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• v.19 no.1
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• pp.116-122
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• 2012

The antioxidant activities of $makgeolli$ and other alcoholic beverages were compared. Based on the same volume (70 ${\mu}L$ eq.) of the alcoholic beverages, the 2,2'-azinobis (3-ethylbenzothiazoline-6-sulfonic acid ammonium salt) (ABTS+) radical-scavenging activities were as follows: whisky > $makgeolli$ crude extract (MCE) > rice wine (RW) > clarified $makgeolli$ (CM) > soju. Based on the same alcohol concentration (6%) of the alcoholic beverages, however, $makgeolli$ showed the highest activity. In addition, based on the same volume (70 ${\mu}L$ eq.), the inhibition effects against the formation of cholesteryl ester hydroperoxide (CE-OOH) were as follows: soju > whisky > RW > MCE > CM. Based on the same alcohol concentration (6%), however, the inhibition effects against the formation of CE-OOH were as follows: RW > MCE > soju > whisky > CM. Therefore, it was suggested that $makgeolli$ may contain radical-scavenging- and metal-ion-chelate-type antioxidants and may increase the antioxidant activity in the blood.